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https://www.gradesaver.com/textbooks/math/algebra/algebra-1/chapter-11-rational-expressions-and-functions-11-1-simplifying-rational-expressions-practice-and-problem-solving-exercises-page-655/15 | ## Algebra 1
Published by Prentice Hall
# Chapter 11 - Rational Expressions and Functions - 11-1 Simplifying Rational Expressions - Practice and Problem-Solving Exercises - Page 655: 15
#### Answer
2/(b+4) ; b cannot equal 4 or -4
#### Work Step by Step
In order to simplify, we want something to be both in the numerator and the denominator of the fraction so it can be canceled out. Thus, we factor and obtain: $(2b-8)/b^{2}-16 \\\\ 2(b-4) / (b-4)(b+4) \\\\ 2/(b+4)$ b cannot equal 4 or -4, for if b equaled 4 or -4, the denominator of the fraction would cancel out to 0, which is not allowed.
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7815629839897156, "perplexity": 962.381634849401}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-04/segments/1547583657557.2/warc/CC-MAIN-20190116175238-20190116201238-00010.warc.gz"} |
https://brilliant.org/problems/graph-is-bell-curve-why/ | Graph is Bell Curve. Why?
What is the value of positive integer $n$ such that $\large { 1000 - n \choose n}$ is maximized?
× | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 2, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8209339380264282, "perplexity": 481.44380838551785}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046153223.30/warc/CC-MAIN-20210727072531-20210727102531-00116.warc.gz"} |
https://www.physicsforums.com/threads/yield-point.876654/ | # Yield point
1. Jun 24, 2016
### foo9008
1. The problem statement, all variables and given/known data
I was told that yield point is a point which the material which will have an appreciable elongation of yielding without any increase in load . my question is If there's no increase load , how can the material elongate ?
2. Relevant equations
3. The attempt at a solution
IMO , it's wrong.... can somone clarify ? if there's no force applied , how can the material elongate itself ?
2. Jun 24, 2016
### SteamKing
Staff Emeritus
You probably should start asking for references for all this stuff you are being told.
Here is a discussion of what yielding actually consists:
https://en.wikipedia.org/wiki/Yield_(engineering)
3. Jun 24, 2016
### PhanthomJay
There is a force applied, it is just that in the non elastic or idealized plastic region, it doesn't have to increase from the force required at yield (it doesn't follow Hooke's Law) and it sometimes decreases at the higher strains, but it doesn't go to the 0 or 'no force' condition.
4. Jun 24, 2016
### foo9008
what do you mean by it here ? i'm confused
5. Jun 24, 2016
### PhanthomJay
In the elastic region of stress and strain, you apply an increasing force to achieve and increasing deformation, per Hookes Law. Once you reach the idealized yield point, say at a force P_y, you then get into the plastic range, and Hookes law becomes invalid. At this point, you do not have to increase the load to get increasing strain. You now more or less can keep the force at a constant value P_y and the material will exhibit increasing strain. Your question asked why does it continue to stretch with no force applied. But there is a force applied, namely, P_y.
6. Jun 24, 2016
### foo9008
Do you mean the object will continue to stretch with the same force applied (constant) , but not increasing force?
7. Jun 24, 2016
### PhanthomJay
Yes
8. Aug 17, 2016
### foo9008
I have 2 graphs below, to show the yield point, in the first graph, the stress is constant from point B to C (C is yield point)(B and C are at the same level of stress), that means the force is constant,right?
For the second diagram, the yield point is slightly higher than the elastic limit point...Which of it is correct?
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• ###### 363.PNG
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9. Aug 19, 2016
### PhanthomJay
The first diagram is for materials like steel and the second is more like for materials such as aluminum. They are both more or less correct.
Have something to add?
Draft saved Draft deleted
Similar Discussions: Yield point | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8359136581420898, "perplexity": 1964.9650006715217}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-47/segments/1510934806066.5/warc/CC-MAIN-20171120130647-20171120150647-00675.warc.gz"} |
https://docs.lammps.org/timestep.html | $$\renewcommand{\AA}{\text{Å}}$$
# timestep command¶
## Syntax¶
timestep dt
• dt = timestep size (time units)
## Examples¶
timestep 2.0
timestep 0.003
## Description¶
Set the timestep size for subsequent molecular dynamics simulations. See the units command for the time units associated with each choice of units that LAMMPS supports.
The default value for the timestep size also depends on the choice of units for the simulation; see the default values below.
When the run style is respa, dt is the timestep for the outer loop (largest) timestep.
none
## Default¶
choice of units time units default timestep size lj $$\tau$$ 0.005 $$\tau$$ real fs 1.0 fs metal ps 0.001 ps si s 1.0e-8 s (10 ns) cgs s 1.0e-8 s (10 ns) electron fs 0.001 fs micro $$\mu$$s 2.0 $$\mu$$s nano ns 0.00045 ns | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5587388277053833, "perplexity": 11846.601238681566}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945287.43/warc/CC-MAIN-20230324144746-20230324174746-00354.warc.gz"} |
https://www.albert.io/learn/ap-calculus-ab-bc/question/3rd-non-zero-term-of-taylor-series-of-dollarsin-xdollar | Limited access
Which of the following is the $3^{rd}$ nonzero term in the Taylor series for $f(x) = \sin x$ centered at $x = π$?
A
$\cfrac{( x-\pi ) ^{ 5 }}{5!}$
B
$-\cfrac{( x-\pi ) ^{ 5 }}{5!}$
C
$\cfrac{(x-\pi)^3}{3!}$
D
$-\cfrac{(x-\pi)^3}{3!}$
Select an assignment template | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.38626232743263245, "perplexity": 511.10847991565817}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-17/segments/1492917120001.0/warc/CC-MAIN-20170423031200-00173-ip-10-145-167-34.ec2.internal.warc.gz"} |
http://philpapers.org/s/T.%20D.%20Rogers | ## Search results for 'T. D. Rogers' (try it on Scholar)
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6. James D. Sellmann (1999). David L. Hall, and Roger T. Ames, Thinking From the Hun: Self Truth, and Transcendence in Chinese and Western Culture. Journal of Chinese Philosophy 26 (4):513-520.score: 63.0
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7. Roger Gil (2011). Le comportement de Pilate au cours du procès de Jésus témoigne-t-il d'un dilemme moral ? Revue des Sciences Philosophiques Et Théologiques 4:719-742.score: 63.0
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Machine generated contents note: Part I. Introduction: 1. Personal epistemology in the classroom: a welcome and guide for the reader Florian C. Feucht and Lisa D. Bendixen; Part II. Frameworks and Conceptual Issues: 2. Manifestations of an epistemological belief system in pre-k to 12 classrooms Marlene Schommer-Aikins, Mary Bird, and Linda Bakken; 3. Epistemic climates in elementary classrooms Florian C. Feucht; 4. The integrative model of personal epistemology development: theoretical underpinnings and implications for education Deanna C. Rule and Lisa D. (...)
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In the second edition of this groundbreaking text in non-Western philosophy, sixteen experts introduce some of the great philosophical traditions in the world. The essays unveil exciting, sophisticated philosophical traditions that are too often neglected in the western world. The contributors include the leading scholars in their fields, but they write for students coming to these concepts for the first time. Building on revisions and updates to the original, this new edition also considers three philosophical traditions for the first time—Jewish, (...)
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Each contributor to this book has used personal experience as the basis from which to frame his individual sociological perspectives. Because they have personalized their work, their accounts are real, and recognizable as having come from 'real' persons, about 'real' experiences. There are no objectively-distanced disembodied third person entities in these accounts. These writers are actual people whose stories will make you laugh, cry, think, and want to know more.
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Featuring contributions from the world's most highly esteemed Asian philosophy scholars, this important encyclopedia covers the complex and increasingly influential field of Chinese thought, from earliest recorded times to the present day. Including coverage on the subject previously unavailable to English speakers, the Encyclopedia sheds light on the extensive range of concepts, movements, philosophical works, and thinkers that populate the field. It includes a thorough survey of the history of Chinese philosophy; entries on all major thinkers from Confucius to Mou (...)
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21. Roger D. Maddux (1992). Relation Algebras of Every Dimension. Journal of Symbolic Logic 57 (4):1213-1229.score: 15.0
Conjecture (1) of [Ma83] is confirmed here by the following result: if $3 \leq \alpha < \omega$, then there is a finite relation algebra of dimension α, which is not a relation algebra of dimension α + 1. A logical consequence of this theorem is that for every finite α ≥ 3 there is a formula of the form $S \subseteq T$ (asserting that one binary relation is included in another), which is provable with α + 1 variables, but not (...) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4841829538345337, "perplexity": 13535.747857359662}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246636104.0/warc/CC-MAIN-20150417045716-00112-ip-10-235-10-82.ec2.internal.warc.gz"} |
http://mathoverflow.net/users/15292/rafaelm | # rafaelm
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11 Limits in category theory and analysis 8 Interesting mathematical documentaries 1 Movies about mathematics/mathematicians
# 313 Reputation
+125 Limits in category theory and analysis +30 Sheaves of $\mathbb Z$-modules = sheaves of abelian groups +40 Interesting mathematical documentaries +5 Two definitions of Čech cohomology
# 2 Questions
6 Sheaves of $\mathbb Z$-modules = sheaves of abelian groups 3 Two definitions of Čech cohomology
# 8 Tags
11 ct.category-theory 0 cohomology 11 limits 0 ag.algebraic-geometry 0 sheaves × 2 0 big-list 0 soft-question × 2 0 sheaf-theory
# 3 Accounts
Mathematics 513 rep 312 MathOverflow 313 rep 39 TeX - LaTeX 165 rep 4 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9866397380828857, "perplexity": 8222.0930421377}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-42/segments/1414119650193.38/warc/CC-MAIN-20141024030050-00029-ip-10-16-133-185.ec2.internal.warc.gz"} |
https://gamedev.stackexchange.com/questions/150493/how-can-i-start-rotating-object-slowly-smooth-and-then-stop-the-rotation-also-sl | # How can i start rotating object slowly smooth and then stop the rotation also slowly smooth?
In the top of the script:
public FirstPersonController fpc;
public float speed;
In the Update
void Update()
{
fpc.transform.localRotation = Quaternion.Slerp(fpc.transform.rotation,
Quaternion.Euler(0, 0, 0), speed * Time.deltaTime);
}
The problem is that the rotation start immediately. And i want it to start slowly smooth then it will get some speed and then near the end to slowly smooth again until stop.
Update:
This is the complete script for now:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityStandardAssets.Characters.FirstPerson;
{
public UnityStandardAssets.ImageEffects.Blur blur;
public UnityStandardAssets.ImageEffects.BlurOptimized blurOptimized;
public FirstPersonController fpc;
public float startAcceleration = 0.6f;
public float endAcceleration = 0.6f;
public float maxSpeed = 1.0f;
private Material material;
private float targetAlpha = 0;
private float lerpParam;
private float startAlpha = 1;
private bool rotated = false;
private float rotationSpeed;
private Quaternion clampedTargetRotation;
private bool start;
void Start()
{
material = GetComponent<Renderer>().material;
SetMaterialAlpha(1);
fpc.enabled = false;
}
void Update()
{
lerpParam += Time.deltaTime;
float alpha = Mathf.Lerp(startAlpha, targetAlpha, lerpParam / fadeDuration);
SetMaterialAlpha(alpha);
if (alpha == 0)
{
fpc.enabled = true;
if (rotated == false)
{
fpc.GetComponent<FirstPersonController>().enabled = false;
rotationSpeed = Mathf.Clamp(rotationSpeed + startAcceleration * Time.deltaTime, 0, maxSpeed);
rotationSpeed = Mathf.Clamp(rotationSpeed - endAcceleration * Time.deltaTime, 0, maxSpeed);
clampedTargetRotation = Quaternion.RotateTowards(fpc.transform.localRotation, whateverRotationTokeepGoing, rotationSpeed * Time.deltaTime);
fpc.transform.localRotation = clampedTargetRotation;
}
if (fpc.transform.localRotation == Quaternion.Euler(0,0,0))
{
fpc.GetComponent<FirstPersonController>().enabled = true;
blur.enabled = false;
blurOptimized.enabled = false;
rotated = true;
}
}
}
public void FadeTo(float alpha, float duration)
{
startAlpha = material.color.a;
targetAlpha = alpha;
lerpParam = 0;
}
private void SetMaterialAlpha(float alpha)
{
Color color = material.color;
color.a = alpha;
material.color = color;
}
}
My problem is in the rotation part:
if (rotated == false)
{
fpc.GetComponent<FirstPersonController>().enabled = false;
rotationSpeed = Mathf.Clamp(rotationSpeed + startAcceleration * Time.deltaTime, 0, maxSpeed);
rotationSpeed = Mathf.Clamp(rotationSpeed - endAcceleration * Time.deltaTime, 0, maxSpeed);
clampedTargetRotation = Quaternion.RotateTowards(fpc.transform.localRotation, whateverRotationTokeepGoing, rotationSpeed * Time.deltaTime);
fpc.transform.localRotation = clampedTargetRotation;
}
The rotation should start from the current fpc rotation state and end at 0,0,0 This is where the rotation should be end when fpc is 0,0,0
if (fpc.transform.localRotation == Quaternion.Euler(0,0,0))
If fpc rotation is at 0,0,0 then stop. Between the start and stop make the whole rotation operation.
Just add an angular acceleration to your angular speed, the starting acceleration and the ending acceleration can be different:
void Update()
{
float speed;
Quaternion clampedTargetRotation;
if(start)
{
speed = Mathf.Clamp(speed + startAcceleration * Time.deltaTime, 0, maxSpeed);
}
else
{
speed = Mathf.Clamp(speed - endAcceleration* Time.deltaTime, 0, maxSpeed);
}
clampedTargetRotation = Quaternion.RotateTowards(fpc.transform.localRotation, whateverRotationTokeepGoing, speed * Time.deltaTime);
fpc.transform.localRotation = clampedTargetRotation;
}
N.B. this is just a "sketch" of solution
• I just edited now my question added the complete script i'm using for now and i'm trying to use your solution too. My problem is where to use the start bool i mean how to decide when it start and when ending ? I know when i want it to stop rotating when the fpc rotation is at 0,0,0 then i also enable other scripts so i want it to stop the rotation at this point and start from it's current rotation state. Nov 7 '17 at 11:21
• Also i'm not sure what should be the whateverRotationTokeepGoing Nov 7 '17 at 11:22
• Do you want to rotate toward a fixed rotation or do you want to just spin on an axis? Nov 7 '17 at 17:14 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.25268399715423584, "perplexity": 13065.171100748019}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320300573.3/warc/CC-MAIN-20220129062503-20220129092503-00398.warc.gz"} |
http://www.komal.hu/verseny/feladat.cgi?a=feladat&f=M342&l=en | Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
# Problem M. 342. (May 2014)
M. 342. Measure the instantaneous speed of a table-tennis ball, which was dropped in static air, and plot the speed both as a function of the distance covered and as a function of the elapsed time. What will the terminal speed of the ball be?
(6 pont)
Deadline expired on June 10, 2014.
### Statistics:
17 students sent a solution. 6 points: Asztalos Bogdán, Holczer András, Horicsányi Attila, Juhász Péter, Nagy Gergely, Sal Kristóf. 5 points: Antalicz Balázs, Berta Dénes, Fekete Panna, Frim Bálint, Olosz Balázs, Szépfalvi Bálint. 4 points: 2 students. 3 points: 1 student. 2 points: 2 students.
Problems in Physics of KöMaL, May 2014 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8607721924781799, "perplexity": 15393.513654174487}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257647519.62/warc/CC-MAIN-20180320170119-20180320190119-00562.warc.gz"} |
http://www.ck12.org/book/Basic-Algebra/r1/section/7.2/ | <img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />
# 7.2: Solving Systems by Substitution
Difficulty Level: At Grade Created by: CK-12
While the graphical approach to solving systems is helpful, it may not always provide exact answers. Therefore, we will learn a second method to solving systems. This method uses the Substitution Property of Equality.
Substitution Property of Equality: If \begin{align*}y=\end{align*} an algebraic expression, then the algebraic expression can be substituted for any \begin{align*}y\end{align*} in an equation or an inequality.
Consider the racing example from the previous lesson.
Peter and Nadia like to race each other. Peter can run at a speed of 5 feet per second and Nadia can run at a speed of 6 feet per second. To be a good sport, Nadia likes to give Peter a head start of 20 feet. How long does Nadia take to catch up with Peter? At what distance from the start does Nadia catch up with Peter?
The two racers' information was translated into two equations.
Peter: \begin{align*}d=5t+20\end{align*}
Nadia: \begin{align*}d=6t\end{align*}
We want to know when the two racers will be the same distance from the start. This means we can set the two equations equal to each other.
\begin{align*}5t+20=6t\end{align*}
Now solve for \begin{align*}t\end{align*}.
\begin{align*}5t-5t+20& =6t-5t\\ 20& = 1t\end{align*}
After 20 seconds, Nadia will catch Peter.
Now we need to determine how far from the distance the two runners are. You already know \begin{align*}20=t\end{align*}, so we will substitute to determine the distance. Using either equation, substitute the known value for \begin{align*}t\end{align*} and find \begin{align*}d\end{align*}.
\begin{align*}d=5(20)+20 \rightarrow 120\end{align*}
When Nadia catches Peter, the runners are 120 feet from the starting line.
The Substitution Method is useful when one equation of the system is of the form \begin{align*}y=\end{align*} algebraic expression or \begin{align*}x=\end{align*} algebraic expression.
Example 1: Solve the system \begin{align*}\begin{cases} x+y=2\\ \qquad y=3 \end{cases}\end{align*}
Solution: The second equation is solved for the variable \begin{align*}x\end{align*}. Therefore, we can substitute the value “3” for any \begin{align*}y\end{align*} in the system.
\begin{align*}x+y=2 \rightarrow x+3=2\end{align*}
Now solve the equation for \begin{align*}x:\end{align*} \begin{align*}x+3-3& =2-3\\ x & = -1\end{align*}
The \begin{align*}x-\end{align*}coordinate of the intersection of these two equations is –1. Now we must find the \begin{align*}y-\end{align*}coordinate using substitution.
\begin{align*}x+y & = 2 \rightarrow (-1)+y=2\\ -1+1+y& = 2+1\\ y & = 3\end{align*}
As seen in the previous lesson, the solution to the system is (–1, 3).
Example: Find the solution to the system \begin{align*}\begin{cases} y=3x-5\\ y=-2x+5 \end{cases}\end{align*} using substitution.
Solution: Each equation is equal to the variable \begin{align*}y\end{align*}, therefore the two algebraic expressions must equal each other.
\begin{align*}3x-5=-2x+5\end{align*}
Solve for \begin{align*}x\end{align*}.
\begin{align*}3x-5+5&=-2x+5+5\\ 3x+2x&=-2x+2x+10\\ 5x&=10\\ x&=2\end{align*}
The \begin{align*}x-\end{align*}coordinate of the intersection of the two lines is 2. Now you must find the \begin{align*}y-\end{align*}coordinate using either of the two equations.
\begin{align*}y=-2(2)+5=1\end{align*}
The solution to the system is \begin{align*}x=2, \ y=1\end{align*} or (2, 1).
## Solving Real-World Systems by Substitution
Example: Anne is trying to choose between two phone plans. Vendaphone’s plan costs $20 per month, with calls costing an additional 25 cents per minute. Sellnet’s plan charges$40 per month, but calls cost only 8 cents per minute. Which should she choose?
Solution: Anne’s choice will depend upon how many minutes of calls she expects to use each month. We start by writing two equations for the cost in dollars in terms of the minutes used. Since the number of minutes is the independent variable, it will be our \begin{align*}x\end{align*}. Cost is dependent on minutes. The cost per month is the dependent variable and will be assigned \begin{align*}y\end{align*}.
\begin{align*}& \text{For Vendafone} && y =0.25x+20\\ & \text{For Sellnet} && y = 0.08x+40\end{align*}
By graphing two equations, we can see that at some point the two plans will charge the same amount, represented by the intersection of the two lines. Before this point, Sellnet’s plan is more expensive. After the intersection, Sellnet’s plan is cheaper.
Use substitution to find the point that the two plans are the same. Each algebraic expression is equal to \begin{align*}y\end{align*}, so they must equal each other.
\begin{align*}0.25x+20 & =0.08x+40 && \text{Subtract 20 from both sides.}\\ 0.25x & = 0.08x+20 && \text{Subtract} \ 0.08x \ \text{from both sides.}\\ 0.17x & = 20 && \text{Divide both sides by 0.17.}\\ x & = 117.65 \ \text{minutes} && \text{Rounded to two decimal places.}\end{align*}
We can now use our sketch, plus this information, to provide an answer. If Anne will use 117 minutes or fewer every month, she should choose Vendafone. If she plans on using 118 or more minutes, she should choose Sellnet.
## Mixture Problems
Systems of equations arise in chemistry when mixing chemicals in solutions and can even be seen in things like mixing nuts and raisins or examining the change in your pocket!
By rearranging one sentence in an equation into \begin{align*}y=\end{align*} algebraic expression or \begin{align*}x=\end{align*} algebraic expression, you can use the Substitution Method to solve the system.
Example: Nadia empties her purse and finds that it contains only nickels and dimes. If she has a total of 7 coins and they have a combined value of 55 cents, how many of each coin does she have?
Solution: Begin by choosing appropriate variables for the unknown quantities. Let \begin{align*}n=\end{align*} the number of nickels and \begin{align*}d=\end{align*} the number of dimes.
There are seven coins in Nadia’s purse: \begin{align*}n+d=7\end{align*}.
The total is 55 cents: \begin{align*}0.05n+0.10d=0.55\end{align*}.
The system is: \begin{align*}\begin{cases} \qquad \quad \ \ n+d=7\\ 0.05n+0.10d=0.55 \end{cases}\end{align*}.
We can quickly rearrange the first equation to isolate \begin{align*}d\end{align*}, the number of dimes: \begin{align*}d=7-n\end{align*}.
Using the Substitution Property, every \begin{align*}d\end{align*} can be replaced with the expression \begin{align*}7-n\end{align*}.
\begin{align*}0.05n+0.10(7-n)&=0.55\\ \text{Now solve for} \ n: \qquad 0.05n+0.70-0.10n&=0.55 \qquad \text{Distributive Property}\\ -0.05n+0.70&=0.55 \qquad \text{Add like terms.}\\ -0.05n&=-0.15 \quad \ \text{Subtract} \ 0.70.\\ n& =3 \qquad \quad \ \text{Divide by} \ -0.05.\end{align*}
Nadia has 3 nickels. There are seven coins in the purse; three are nickels so four must be dimes.
Check to make sure this combination is 55 cents: \begin{align*}0.05(3)+ 0.10(4)= 0.15+0.40=0.55\end{align*}.
## Chemical Mixtures
Example: A chemist has two containers, Mixture \begin{align*}A\end{align*} and Mixture \begin{align*}B\end{align*}. Mixture \begin{align*}A\end{align*} has a 60% copper sulfate concentration. Mixture \begin{align*}B\end{align*} has a 5% copper sulfate concentration. The chemist needs to have a mixture equaling 500 mL with a 15% concentration. How much of each mixture does the chemist need?
Solution: Although not explicitly stated, there are two equations involved in this situation.
• Begin by stating the variables. Let \begin{align*}A = mixture \ A \ and \ B = mixture \ B\end{align*}.
• The total mixture needs to have 500 mL of liquid.
Equation 1 (how much total liquid): \begin{align*}A+B=500\end{align*}.
• The total amount of copper sulfate needs to be 15% of the total amount of solution (500 mL). \begin{align*}0.15 \cdot 500=75 \ ounces\end{align*}
Equation 2 (how much copper sulfate the chemist needs): \begin{align*}0.60A+0.05B=75\end{align*}
\begin{align*}\begin{cases} A+B=500\\ 0.60A+0.05B=75 \end{cases}\end{align*}
By rewriting equation 1, the Substitution Property can be used: \begin{align*}A=500-B\end{align*}.
Substitute the expression \begin{align*}500-B\end{align*} for the variable \begin{align*}A\end{align*} in the second equation.
\begin{align*}0.60(500-B)+0.05B=75\end{align*}
Solve for \begin{align*}B\end{align*}.
\begin{align*}300-0.60B+0.05B& =75 && \text{Distributive Property}\\ 300-0.55B&=75 && \text{Add like terms.}\\ -0.55B&=-225 && \text{Subtract} \ 300.\\ B & \approx 409 \ mL\end{align*}
The chemist needs approximately 409 mL of mixture \begin{align*}B\end{align*}. To find the amount of mixture \begin{align*}A\end{align*}, use the first equation: \begin{align*}A+409=500\end{align*}
\begin{align*}A=91 \ mL\end{align*}
The chemist needs 91 milliliters of mixture \begin{align*}A\end{align*} and 409 milliliters of mixture \begin{align*}B\end{align*} to get a 500 mL solution with a 15% copper sulfate concentration.
## Practice Set
Sample explanations for some of the practice exercises below are available by viewing the following video. Note that there is not always a match between the number of the practice exercise in the video and the number of the practice exercise listed in the following exercise set. However, the practice exercise is the same in both.
1. Explain the process of solving a system using the Substitution Property.
2. Which systems are easier to solve using substitution?
Solve the following systems. Remember to find the value for both variables!
1. \begin{align*}\begin{cases} y=-3\\ 6x-2y=0 \end{cases}\end{align*}
2. \begin{align*}\begin{cases} -3-3y=6\\ y=-3x+4 \end{cases}\end{align*}
3. \begin{align*}\begin{cases} y=3x+16\\ y=x+8 \end{cases}\end{align*}
4. \begin{align*}\begin{cases} y=-6x-3\\ y=3 \end{cases}\end{align*}
5. \begin{align*}\begin{cases} y=-2x+5\\ y=-1-8x \end{cases}\end{align*}
6. \begin{align*}\begin{cases} y=6+x\\ y=-2x-15 \end{cases}\end{align*}
7. \begin{align*}\begin{cases} y=-2\\ y=5x-17 \end{cases}\end{align*}
8. \begin{align*}\begin{cases} x+y=5\\ 3x+y=15 \end{cases}\end{align*}
9. \begin{align*}\begin{cases} 12y-3x=-1\\ x-4y=1 \end{cases}\end{align*}
10. \begin{align*}x+2y=9\!\\ 3x+5y=20 \end{align*}
11. \begin{align*}x-3y=10\!\\ 2x+y=13 \end{align*}
12. Solve the system \begin{align*}\begin{cases} y=\frac{1}{4} x-14\\ y=\frac{19}{8} x+7 \end{cases}\end{align*} by graphing and substitution. Which method do you prefer? Why?
13. Of the two non-right angles in a right angled triangle, one measures twice that of the other. What are the angles?
14. The sum of two numbers is 70. They differ by 11. What are the numbers?
15. A rectangular field is enclosed by a fence on three sides and a wall on the fourth side. The total length of the fence is 320 yards. If the field has a total perimeter of 400 yards, what are the dimensions of the field?
16. A ray cuts a line forming two angles. The difference between the two angles is \begin{align*}18^\circ\end{align*}. What does each angle measure?
17. I have $15.00 and wish to buy five pounds of mixed nuts for a party. Peanuts cost$2.20 per pound. Cashews cost $4.70 per pound. How many pounds of each should I buy? 18. A chemistry experiment calls for one liter of sulfuric acid at a 15% concentration, but the supply room only stocks sulfuric acid in concentrations of 10% and in 35%. How many liters of each should be mixed to give the acid needed for the experiment? 19. Bachelle wants to know the density of her bracelet, which is a mix of gold and silver. Density is total mass divided by total volume. The density of gold is 19.3 g/cc and the density of silver is 10.5 g/cc. The jeweler told her that the volume of silver used was 10 cc and the volume of gold used was 20 cc. Find the combined density of her bracelet. 20. Jeffrey wants to make jam. He needs a combination of raspberries and blackberries totaling six pounds. He can afford$11.60. How many pounds of each berry should he buy?
Mixed Review
1. The area of a square is \begin{align*}96 \ inches^2\end{align*}. Find the length of a square exactly.
2. The volume of a sphere is \begin{align*}V= \frac{4}{3} \pi r^3\end{align*}, where \begin{align*}r=radius\end{align*}. Find the volume of a sphere with a diameter of 11 centimeters.
3. Find:
1. the additive inverse and
2. the multiplicative inverse of 7.6.
4. Solve for \begin{align*}x: \frac{1.5}{x}=6\end{align*}.
5. The temperature in Fahrenheit can be approximated by crickets using the rule “Count the number of cricket chirps in 15 seconds and add 40.”
1. What is the domain of this function?
2. What is the range?
3. Would you expect to hear any crickets at \begin{align*}32^\circ F\end{align*}? Explain your answer.
4. How many chirps would you hear if the temperature were \begin{align*}57^\circ C\end{align*}?
6. Is 4.5 a solution to \begin{align*}45-6x \le 18\end{align*}?
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https://www.livescience.com/50777-calculus.html | Calculus is a branch of mathematics that explores variables and how they change by looking at them in infinitely small pieces called infinitesimals. Calculus, as it is practiced today, was invented in the 17th century by British scientist Isaac Newton (1642 to 1726) and German scientist Gottfried Leibnitz (1646 to 1716), who independently developed the principles of calculus in the traditions of geometry and symbolic mathematics, respectively.
While these two discoveries are most important to calculus as it is practiced today, they were not isolated incidents. At least two others are known: Archimedes (287 to 212 B.C.) in Ancient Greece and Bhāskara II (A.D. 1114 to 1185) in medieval India developed calculus ideas long before the 17th century. Tragically, the revolutionary nature of these discoveries either wasn't recognized or else was so buried in other new and difficult-to-understand ideas that they were nearly forgotten until modern times.
The word "calculus" has a modest origin, deriving from similar words such as "calculation" and "calculate," but all these words derive from a Latin (or perhaps even older) root meaning "pebble." In the ancient world, calculi were stone beads used to keep track of livestock and grain reserves (and today, calculi are small stones that form in the gallbladder, kidneys or other parts of the body).
To understand what is meant by infinitesimal, consider the formula for the area of a circle: A=πr². The following demonstration is adapted from one given by Professor Steve Strogatz of Cornell, who points out that despite this formula's simplicity, it is impossible to derive without the utility of infinitesimals.
To start, we recognize that the circumference of a circle divided by its diameter (or twice the radius) is approximately 3.14, a ratio denoted as pi (π). With this information, we can write the formula for a circle's circumference: C=2πr. To determine a circle's area, we can start by cutting the circle into eight pie wedges and rearranging them to look like this:
We see the short, straight edge is equal to the original circle's radius (r), and the long, wavy side is equal to half the circle's circumference (πr). If we repeat this with 16 pieces, it looks like this:
Again, we see the short, straight edge is equal to the original circle's radius (r), and the long, wavy side is equal to half the circle's circumference (πr), but the angle between the sides is closer to a right angle and the long side is less wavy. No matter how much we increase the number of pieces we cut the circle into, the short and long sides keep the same respective lengths, the angle between the sides gets progressively closer to a right angle, and the long side gets progressively less wavy.
Now, let's imagine we cut the pie into an infinite number of slices. In the language of mathematics, the slices are described as "infinitesimally thick," since the number of slices "is taken to the limit of infinity." At this limit, the sides still have lengths r and πr, but the angle between them is actually a right angle and the waviness of the long side has disappeared, meaning we now have a rectangle.
Calculating the area is now just the length × width: πr × r=πr². This case-in-point example illustrates the power of examining variables, such as the area of a circle, as a collection of infinitesimals.
The study of calculus has two halves. The first half, called differential calculus, focuses on examining individual infinitesimals and what happens within that infinitely small piece. The second half, called integral calculus, focuses on adding an infinite number of infinitesimals together (as in the example above). That integrals and derivatives are the opposites of each other, is roughly what is referred to as the Fundamental Theorem of Calculus. To explore how this is, let's draw on an everyday example:
A ball is thrown straight into the air from an initial height of 3 feet and with an initial velocity of 19.6 feet per second (ft/sec).
If we graph the ball's vertical position over time, we get a familiar shape known as a parabola.
At every point along this curve, the ball is changing velocity, so there's no timespan where the ball is traveling at a constant rate. We can, however, find the average velocity over any timespan. For example, to find the average velocity from 0.1 seconds to 0.4 seconds, we find the position of the ball at those two times and draw a line between them. This line will rise some amount compared with its width (how far it "runs"). This ratio, often referred to as slope, is quantified as rise ÷ run. On a position versus time graph, a slope represents a velocity. The line rises from 4.8 feet to 8.3 feet for a rise of 3.5 feet. Likewise, the line runs from 0.1 seconds to 0.4 seconds for a run of 0.3 seconds. The slope of this line is the ball's average velocity throughout this leg of the journey: rise ÷ run = 3.5 feet ÷ 0.3 seconds = 11.7 feet per second (ft/sec).
At 0.1 seconds, we see the curve is a bit steeper than the average we calculated, meaning the ball was moving a bit faster than 11.7 ft/sec. Likewise, at 0.4 seconds, the curve is a bit more level, meaning the ball was moving a bit slower than 11.7 ft/sec. That the velocity progressed from faster to slower means there had to be an instant at which the ball was actually traveling at 11.7 ft/sec. How might we determine the precise time of this instant?
Let's back up and observe that the span of 0.1 seconds to 0.4 seconds isn't the only timespan over which the ball had an average velocity of 11.7 ft/sec. So long as we maintain the line's slope, we can move it any place over this curve and the average velocity over the timespan between the two places the line intersects the curve will still be 11.7 ft/sec. If we move the line farther toward the edge of the parabola, the timespan decreases. When the timespan reaches zero, the points land on the same spot and the line is said to be tangent to (just barely resting against) the parabola. The timespan is described as having been "taken to the limit of zero."
Here's where the notion of infinitesimals enters into play. Until this point, we've talked about velocity over a finite span of time, but now we're talking about a velocity at an instant; a timespan of infinitesimal length. Notice how we can't take the slope between two points that are infinitesimally far apart; we'd have rise ÷ run = 0 feet ÷ 0 seconds, which doesn't make any sense. To find the slope at any point along the curve, we instead find the slope of the tangent line. The results of six points are plotted below:
This graph is what's known as the original graph's derivative. In the language of mathematics and physics, it's said that "the derivative of an object's position with respect to time is that object's velocity."
This process works in reverse, too. The opposite of a derivative is an integral. Thus, "the integral of an object's velocity with respect to time is that object's position." We found derivatives by calculating slopes; we find integrals by calculating areas. On a velocity versus time graph, an area represents a length. The matter of finding areas under a graph is relatively simple when dealing with triangles and trapezoids, but when graphs are curves instead of straight lines, it is necessary to divide an area into an infinite number of rectangles with infinitesimal thickness (similar to how we added an infinite number of infinitesimal pie wedges to get a circle's area).
You might have noticed that this integral graph doesn't quite give us the same vertical-position graph that we started with. This is because it is just one of many vertical-position graphs that all have the same derivative. A few similar curves are shown below:
To determine which of these curves will give us the original graph of position, we must also use some knowledge about the position of the ball at a certain time. Examples of this include the height from which it was thrown (the vertical position of the ball at time zero), or the time at which it hit the ground (the time where the vertical position was zero). This is referred to as an initial condition because we're usually concerned with predicting what happens after, though it's a bit of a misnomer, since an initial condition can also come from the middle or end of a graph. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.877331554889679, "perplexity": 461.2090273398826}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267161350.69/warc/CC-MAIN-20180925083639-20180925104039-00051.warc.gz"} |
https://www.zbmath.org/?q=an%3A1055.62512 | ×
# zbMATH — the first resource for mathematics
Information-theoretic approaches to inference in moment condition models. (English) Zbl 1055.62512
Summary: This paper develops a variant of one-step efficient GMM based on the KLIC rather than empirical likelihood. As in other one-step methods, the authors introduce $$M$$ (the number of moments) auxiliary ‘tilting’ parameters which are used to construct a reweighting of the data so that the reweighted sample obeys all the moment conditions at the parameter estimates. Parameter and overidentification tests can be recast in terms of these tilting parameters; such tests are often startlingly more effective than their conventional counterparts. These performance differences cannot be completely explained by the leading terms of the statistics’ asymptotic expansions.
##### MSC:
62F10 Point estimation 62B10 Statistical aspects of information-theoretic topics
KLIC
Full Text: | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.489914208650589, "perplexity": 2032.1999868939752}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243991685.16/warc/CC-MAIN-20210512070028-20210512100028-00008.warc.gz"} |
https://doc.xuehai.net/b7d79be47349030b168cf4c5c.html | ÇëÊäÈëÄÚÈÝ£º ¡¡
µ±Ç°Î»Ö㺠ÎĵµÏÂÔØ > ËùÓзÖÀà > Scaling of avalanche queues in directed dissipative sandpiles
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# Scaling of avalanche queues in directed dissipative sandpiles
We simulate queues of activity in a directed sandpile automaton in 1+1 dimensions by adding grains at the top row with driving rate $0 < r \leq 1$. The duration of elementary avalanches is exactly described by the distribution \$P_1(t) \sim t^{-3/2}\exp{(-1
a r X i v :c o n d -m a t /0006246v 1 [c o n d -m a t .s t a t -m e c h ] 15 J u n 2000Scaling of avalanche queues in directed dissipative sandpiles Bosiljka Tadi´c 1,?and Vyatcheslav Priezzhev 2,??1Jo¡¦z ef Stefan Institute,P.O.Box 3000,1001Ljubljana,Slovenia 2Bogolubov Laboratory of Theoretical Physics,Joint Institute of Nuclear Research,141980Dubna,Russia Using numerical simulations and analytical methods we study a two-dimensional directed sandpile automaton with nonconservative random defects (concentration c )and varying driving rate r .The automaton is driven only at the top row and driving rate is measured by the number of added particles per time step of avalanche evolution.The probability distribution of duration of elementary avalanches at zero driving rate is exactly given by P 1(t,c )=t ?3/2exp [t ln(1?c )].For driving rates in the interval 0<r ¡Ü1the avalanches are queuing one after another,making increase the periods of non-interrupted activity of the automaton.Recognizing the probability P 1as a distribution of service time of jobs arriving at a server with frequency r ,the model represents a new example of the E,1,GI/¡Þ/1 server queue in the queue theory.We study scaling properties of the busy period and dissipated energy of sequences of non-interrupted activity.In the limit c ¡ú0and varying linear system size L ?1/c we ?nd that at driving rates r ¡ÜL ?1/2the distributions of duration and energy of the avalanche queues are characterized by a multifractal scaling and we determine th
e corresponding spectral functions.For L ?1/c increasing of the driving rate somewhat compensates the energy losses at defects above the line r ?¡Ì | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9319939017295837, "perplexity": 6448.779444781709}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-35/segments/1566027319082.81/warc/CC-MAIN-20190823214536-20190824000536-00382.warc.gz"} |
https://www.acmicpc.net/problem/11016 | 시간 제한 메모리 제한 제출 정답 맞은 사람 정답 비율
1 초 256 MB 0 0 0 0.000%
## 문제
In Fall of 2005, the contest explored a “Summer on the Beach”. One of the most important activities on the beach is lying on the sand and sun bathing. As you are all aware, prolonged exposure to sun can cause painful sunburns, so the use of sunscreen is highly recommended. Another approach pursued by many people is to lie under a parasol, protecting them from rays. But if you know from when to when you will lie at the beach, where should you place the parasol to protect as much of your body as possible?2
Here, we will answer a slightly easier question. Given the position of your body and the parasol, calculate which percentage of your body is exposed to the sun for at least part of the time. For simplicity, we will treat your body as rectangular, of size h × w centimeters. We treat the beach as a two-dimensional plane, with the origin at the center of your body. The parasol is assumed to be a circle of radius r, mounted horizontally at distance d above your body, with the center at the origin as well. You are sunbathing for a period from α1 to α2, where 1 ≤ α1 < α2 ≤ 179 are the angle that the sun makes with the beach at the beginning and end of your sunbath. (Assume that the sun is a point infinitely far away from the Earth, and travels straight from the left to the right.)
2In a French student science competition, one winning entry was a “para-tournesol”, a “sunflower parasol”. Using a light sensor, the parasol moves as the sun does, protecting you as much as possible. We won’t explore that avenue here.
## 입력
The first line contains a number K ≥ 1, which is the number of input data sets in the file. This is followed by K data sets of the following form:
Each data set consists of a single line, containing (in this order) the real numbers w, h, r, d, α1, α2. We will always guarantee that 0.01 ≤ w, h, r, d ≤ 100.
Here is a figure illustrating these quantities. Notice that the sun travels “from your feet to your head”, and not “from your left arm to your right arm”.
## 출력
For each data set, first output “Data Set x:” on a line by itself, where x is its number. Then, output the percentage of your body that will be exposed to sun rays at some time, rounding to two decimals.
Each data set should be followed by a blank line.
## 예제 입력
2
0.5 1.8 5.0 0.2 70.0 120.0
0.5 2.0 0.75 1.0 45.0 90.0
## 예제 출력
Data Set 1:
0.00%
Data Set 2:
76.41% | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2928832471370697, "perplexity": 1269.8956280584794}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698544678.42/warc/CC-MAIN-20161202170904-00406-ip-10-31-129-80.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/lim-sup-lim-inf-definition-convention.169815/ | # Homework Help: Lim sup, lim inf definition/convention
1. May 11, 2007
### quasar987
My book says that if the set of all cluster points is empty, then we write lim sup = $-\infty$ and if the sequence is not bounded above, we write limsup = $+\infty$.
But what if both happen at the same time? for instance consider x_n=1/n. There are no accumulation points and it is unbounded above.
2. May 11, 2007
### NateTG
Maybe I'm getting too tired, but
$$1>\frac{1}{n}$$
is an upper bound, and
$$0$$
is an accumulation point.
You might consider $x_n=n(-1)^n$ which is unbounded in the reals, and doesn't have any real accumulation points. However, in the extedended reals, $\pm \infty$ are cluster points of that sequence, and $+ \infty$ is an upper bound for all sequences.
3. May 11, 2007
### quasar987
It is I who is too tired. I meant to say x_n = n.
4. May 11, 2007
### HallsofIvy
I don't see a problem. Since the set of all cluster points is empty, lim sup= $-\infty$ and since the sequence is not bounded above, limsup= $\infty$.
5. May 11, 2007
### quasar987
Well, actually, the author give the same x_n=n as an example and he write lim sup=+$\infty$.
As if the fact that it is not bounded above takes priority over the fact that the set of all cluster points is empty.
6. May 11, 2007
### AKG
Are "lim sup" and "limsup" supposed to be two different things?
7. May 11, 2007
No, no.
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https://tex.stackexchange.com/questions/97162/horizontal-alignment-of-multiple-glossaries | # Horizontal alignment of multiple glossaries
I utilize the glossariespackage with acronym option as well as an self-defined symbols list. Unfortunately, each glossary aligns different horizontally. Is it possible to make them aligned? Otherwise, it looks distracting to me.
Code:
\documentclass[8pt]{scrartcl}
% LuaLaTeX
\usepackage{luatextra}
\usepackage[xindy,style=long,numberline,savewrites=true,acronym,nomain]{glossaries}
% new group for symbols
\newglossary[slg]{symbolslist}{syi}{syg}{Symbols}
\makeglossaries
% SYMBOLS:
\newglossaryentry{sy:te}{name=$\text{T}_\text{E}$, description={echo time}, sort=sy-echotime, type=symbolslist}
\newglossaryentry{sy:tr}{name=$\text{T}_\text{R}$, description={repetition time}, sort=sy-repetitiontime, type=symbolslist}
% ACRONYMS:
\newacronym{peg}{PEG}{polyethylene glycol}
\begin{document}
\printglossaries
Text Text Text Text Text Text Text Text
Text Text Text Text Text Text Text Text.
.... \gls{sy:tr} .... \gls{sy:te}
\end{document}
I suggest you use the alttree style instead of long and set the width of the name field using \glssetwidest:
\usepackage[xindy,style=alttree,numberline,savewrites=true,acronym,nomain]{glossaries}
\renewcommand*{\glsnamefont}[1]{\textmd{#1}}
• Mh it sure is a an alternative. Is it possible to avoid setting the abbrevation bold? Some math symbols do not get bold rendering it inconsistent. What still bothers me as well is that long entries (page references exceeding a line) start at the beginning of the next line and not at the explanation indentation (as in long). Gonna keep the question open for a little bit longer. – bioslime Feb 7 '13 at 11:22
• @bioslime Just redefine \glsnamefont to cancel the bold. I've added the code to my answer. – Nicola Talbot Feb 7 '13 at 11:28
Okay, as i was eager to keep style=long i came up with something. As Nicola posted you can set \glssetwidestfor the alttree style. Unfortunately, i can't find something similiar for the first entry within long. Therefore, i simply put a dummy entry (blank line) to my symbols list (sorted to be at the end of the list):
% blanc entry used for spacing
Not the nicest solution but it works:
Full Code:
\documentclass[8pt]{scrartcl}
% LuaLaTeX
\usepackage{luatextra}
\usepackage{calc}
\usepackage[xindy,style=long,numberline,savewrites=true,acronym,nomain]{glossaries}
% new group for symbols
\renewcommand{\glsgroupskip}{}
\newglossary[slg]{symbolslist}{syi}{syg}{Symbols}
\renewcommand{\glsgroupskip}{}
% remove dot after each description
\renewcommand*{\glspostdescription}{}
\makeglossaries
% SYMBOLS:
\newglossaryentry{sy:te}{name=$\text{T}_\text{E}$, description={echo time}, sort=sy-echotime, type=symbolslist}
\newglossaryentry{sy:tr}{name=$\text{T}_\text{R}$, description={repetition time}, sort=sy-repetitiontime, type=symbolslist}
\newglossaryentry{sy:ga}{name=\gamma, description={gamma}, sort=sy-gamma, type=symbolslist}
% blanc entry used for spacing
% ACRONYMS:
\newacronym{peg}{PEG}{polyethylene glycol}
%\renewcommand*{\glsnamefont}[1]{\textmd{#1}}
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https://codegolf.stackexchange.com/questions/92011/mirror-mirror-in-the-code/92035 | # Mirror, Mirror, in the Code
Two-dimensional programming languages often have mirror commands like / and \ to redirect the instruction pointer on the grid:
>>>>\
v
v
<<<</
In this challenge, you're given an incoming direction and a mirror and you need to determine the outgoing direction.
## Rules
The incoming direction will be given as one of the characters NESW and the mirror will be given as either / or \. You may receive these in any order. You must use uppercase letters.
You may take input in any convenient format, including a two-character string, a string using some separator between the characters, a pair of characters in a list, or even a pair of singleton strings. If you do use a string with separator, the separator cannot use any of the characters NWSE\/.
Output should be a character from NESW or single-character string.
You may write a program or a function and use any of the our standard methods of receiving input and providing output.
You may use any programming language, but note that these loopholes are forbidden by default.
This is , so the shortest valid answer – measured in bytes – wins.
## Test Cases
There are only 8 possible inputs you need to handle, so there is no excuse for not testing your code on all of them:
N / --> W
N \ --> E
E / --> S
E \ --> N
S / --> E
S \ --> W
W / --> N
W \ --> S
• In languages where backslashes must be escaped on input, are we allowed to assume the input will be "\\" where appropriate?
– JDL
Sep 2 '16 at 10:21
• @JDL The actual string (or character) should contain a single \. If your answer is a function submission that takes a string, then of course you'll need \\ in the source code to call it correctly, but if you're reading your input from standard input, for instance, then it should be a single \. In other words, if you call your language's respective string-length function on the input, the result should always be the same, regardless of whether the input contains / or \. Sep 2 '16 at 11:10
• Alright, I was expecting R to have problems when an unescaped "\" was entered via stdin, but readline() can handle it.
– JDL
Sep 2 '16 at 11:46
• @JDL You probably need to enter the string escaping (duplicating) that symbol, but the resulting string will be "N\" Sep 2 '16 at 11:46
# Python, 40 38 bytes
-2 bytes thanks to @MitchSchwartz (ord(d)+ord(m))%8 -> ord(d)+ord(m)&7
lambda d,m:' NESSWNW'[ord(d)+ord(m)&7]
plain lookup of answer in a list (AKA string) indexed by the smallest mod of the sum of ordinals that works.
Test cases are on ideone
• Dangit, I thought I was being super clever taking the ASCII values, summing them, %8 them, and doing an index. Then I see you posted the same solution over an hour ago. Hah. Have a +1. Sep 2 '16 at 13:31
# Python 2, 40 bytes
lambda c,m,k="NWES":k[k.find(c)^(m>k)+1]
Sp3000 saved one byte (.index.find).
## Explanation
We want to map the directions like so:
\
N ⇄⇄⇄⇄⇄⇄⇄ E
⇅ ⇅
⇅ ⇅
/ ⇅ ⇅ /
⇅ ⇅
⇅ ⇅
W ⇄⇄⇄⇄⇄⇄⇄ S
\
We can assign the directions 2-bit codes, and view both flips as XOR-ing the first and second bits:
xor 2
0 0 ⇄⇄⇄⇄⇄ 1 0
⇅ ⇅
⇅ ⇅
xor 1 ⇅ ⇅ xor 1
⇅ ⇅
⇅ ⇅
0 1 ⇄⇄⇄⇄⇄ 1 1
xor 2
The mapping between bit strings and directions happens using the string k. Now we just need to map mirror characters '/' and '\\' to the values 1 and 2. Since '/' < '\\', we could naïvely use (m>'/')+1 as a formula. But wait! Lexicographically,
'/' < 'NWES' < '\\'
and we have 'NWES' nicely assigned to k! So we can use (m>k)+1 instead.
# CJam, 14 bytes
l1b" NESSWNW"=
How?
l1b" NESSWNW"= -
1b - cast characters as base 1 digits
" NESSWNW" - the string " NESSWNW"
= - modulo index into the string
## Javascript (ES6), 504140 37 bytes
d=>m=>(S="NWES")[S.search(d)^-~(m>S)]
Saved 3 more bytes by using comparison, thanks to Lynn's answer
### Usage
let f =
d=>m=>(S="NWES")[S.search(d)^-~(m>S)]
console.log(f("N")("/")); // --> W
console.log(f("N")("\\")); // --> E
console.log(f("E")("/")); // --> S
console.log(f("E")("\\")); // --> N
console.log(f("S")("/")); // --> E
console.log(f("S")("\\")); // --> W
console.log(f("W")("/")); // --> N
console.log(f("W")("\\")); // --> S
• Clever use of ASCII comparisons to get your condition at the end playing your way... Sep 11 '19 at 1:17
# MATL, 19 17 bytes
'NWSE'jy&mjy+Eq-)
### Explanation
'NWSE' % Push this string
j % Take first input, say 'W'. Stack contains: 'NWSE', 'W'
y % Duplicate from below. Stack: 'NWSE', 'W', 'NWSE'
&m % Index of membership. Stack: 'NWSE', 2
j % Take second input, say '/'. Stack: 'NWSE', 2, '/'
y % Duplicate from below. Stack: 'NWSE', 2, '/', 2
+ % Add (char '/' is converted to code point). Stack: 'NWSE', 2, 49
Eq % Multiply by 2, subtract 1. Stack: 'NWSE', 2, 97
- % Subtract. Stack: 'NWSE', -95
) % Apply -95 as (modular, 1-based) index into 'NWSE'. Stack: 'N'
% Implicitly display
# Pyth, 1716 15 bytes
Thanks to @Jakube and @Maltysen for -1 byte each
@J"NWES"xxJQh>E
A program that takes input of two newline-separated quoted strings, first the direction and then the mirror, and prints the result.
This is a port of @Lynn's Python answer.
Try it online
How it works
@J"NWES"xxJQh>E Program. Inputs: Q, E
J"NWES" J="NWES". Yield J
xJQ J.index(Q)
>E E>Q, lexographically (implicit input fill)
h +1
x Bitwise XOR of the above two
@ Index into J with the above
Implicitly print
• you can save another byte by replacing <QE with >E. Sep 2 '16 at 14:52
# 05AB1E, 14 bytes
‘€Ã‘DIkI'/kÌ^è
‘€Ã‘ # from string "NEWS"
è # get element at index
DIk # index of 1st input in string "NEWS"
^ # XOR
I'/k # index of 2nd input in string "/"
Ì # +2
Try it online!
# Jelly, 14 13 12 bytes
(a port of my Python answer)
-1 byte thanks to @MartinEnder (add a space to end of the string and remove need for modulo 8)
-1 byte thanks to @LuisMendo (take a single string argument rather than two)
OSị“NESSWNW
How?
OSị“NESSWNW - takes a single argument "dm" (direction and mirror), in either order.
strings and lists are equivalent in Jelly
O - ordinal: [ord(d),ord(m)]
S - sum: ord(d)+ord(m)
“NESSWNW - string: "NESSWNW "
ị - fetch modulo index (the string is 8 long and 1-based)
Test it on TryItOnline
# Java 7, 7170 68 bytes
char c(int d,int m){return"NEWS".charAt("NEWS".indexOf(d)^-~(m%2));}
Too bad the charAt and indexOf takes up so much bytes..
Ungolfed & all test cases:
Try it here.
class M{
static char c(int d, int m) {
return "NEWS".charAt("NEWS".indexOf(d) ^ -~(m%2));
}
public static void main(String[] a){
System.out.print(c('N', '/') + " ");
System.out.print(c('N', '\\') + " ");
System.out.print(c('E', '/') + " ");
System.out.print(c('E', '\\') + " ");
System.out.print(c('S', '/') + " ");
System.out.print(c('S', '\\') + " ");
System.out.print(c('W', '/') + " ");
System.out.print(c('W', '\\') + " ");
}
}
Output:
W E S N E W N S
# Python, 6361 59 bytes
lambda d,m,x='NESW'*2:x[x.find(d)+2*(m=='/\\'[d in'NS'])-1]
Pretty simple. Can definitely be golfed more. Decides whether to add 1 or -1 to the input's index in 'NESW'.
This is a lambda expression; to use it, prefix it with f=.
Ideone it!
# Java 8, 6258 56 bytes
(d,m)->"SEWN".charAt("NWES".indexOf(d)^m.indexOf(47)+2);
# Ungolfed test program
import java.util.function.BiFunction;
public class Mirror {
public static void main(String[] args) {
BiFunction<String, String, Character> function = (d,m)->"SEWN".charAt("NWES".indexOf(d)^m.indexOf(47)+2);
System.out.println(function.apply("N", "/")); //W
System.out.println(function.apply("N", "\\")); //E
System.out.println(function.apply("W", "/")); //N
System.out.println(function.apply("W", "\\")); //S
System.out.println(function.apply("E", "/")); //S
System.out.println(function.apply("E", "\\")); //N
System.out.println(function.apply("S", "/")); //E
System.out.println(function.apply("S", "\\")); //W
}
}
## PowerShell v2+, 34 bytes
param($a,$b)"xNESSWNW"[(+$a+$b)%8]
Takes input as two explicit chars, outputs a char.
This works as follows: If we sort the output, we want S / to somehow equal the same as N \, W / to equal E \, etc. Or, at least, produce numbers that are "close enough" yet still distinct. If we look at the ASCII values, we get a table like the below:
In1 In2 Res. Sum
S 83 / 47 --> E 69 -> 130
N 78 \ 92 --> E 69 -> 170
W 87 / 47 --> N 78 -> 134
E 69 \ 92 --> N 78 -> 161
W 87 \ 92 --> S 83 -> 179
E 69 / 47 --> S 83 -> 116
N 78 / 47 --> W 87 -> 125
S 83 \ 92 --> W 87 -> 175
Running a quick brute-forcer on the summations column (derived from summing the ASCII code points of the inputs) shows that if we take the sums modulo 8, we get the following 2 2 | 6 1 | 3 4 | 5 7. That's evidenced in the string "xNESSWNW", as E is at index 2, N is at 6 and 1, and so on.
So, we just need to sum the inputs (implicitly casting from char to int32 along the way), take that %8, and use that to index into our string.
### Test Cases
PS C:\Tools\Scripts\golfing> ('N','/'),('N','\'),('E','/'),('E','\'),('S','/'),('S','\'),('W','/'),('W','\')|%{"$($_[0]) $($_[1]) --> "+(.\mirror-mirror-in-the-code.ps1 ([char]$_[0]) ([char]$_[1]))}
N / --> W
N \ --> E
E / --> S
E \ --> N
S / --> E
S \ --> W
W / --> N
W \ --> S
## Batch, 111 bytes
:goto %1
:W/
:E\
@echo N
@exit/b
:S/
:N\
@echo E
@exit/b
:E/
:W\
@echo S
@exit/b
:N/
:S\
@echo W
Accepts e.g. W/ as a two-character string command line parameter. The \ and / make looping awkward; it would have taken 124 bytes.
• Idk, I count 96 bytes. Did you strip \r from it? Sep 2 '16 at 22:17
• @ConorO'Brien I write my Batch files using Notepad, so, no.
– Neil
Sep 2 '16 at 22:33
# Octave, 30 bytes
Used the same order of arguments as Jonathan Allan.
Takes the input as two-character string 'W\'.
@(x)['NESSWNW'](mod(sum(x),8))
Try it online.
• Nice! You may want to port to MATL: 'NESSWNW 'is) (see all test cases). i is input, s is sum, and ) is indexing, which is modular. I added a space in the string so that the modulo is 8 Sep 2 '16 at 18:59
• Thanks :) I feel it's cheating if I add that as a separate answer, since I haven't written it myself. I can add it to this answer though if you don't want to answer it yourself :) Sep 2 '16 at 19:03
• I understand, I would probably do the same :-) I don't want to modify my answer, as it's a totally different approach I didn't come up with. Not sure it adding it to your answer makes sense, though, as it would be two different languages in the answer Sep 2 '16 at 19:05
• It would be my first MATL answer though :P I see it's longer than your MATL answer, so I don't think I'll add it... Sep 2 '16 at 19:08
# C, 44,35, 34 bytes
f(a,b){return"NWES"[a&a/2&3^b&3];}
It requires two characters as two variables. It takes both lower and upper case. It uses a lot of bit manipulation. The fragment a&a/2 results in a value that has unique values for the lower two bits, &3 cuts off all higher bits. This used as an index into the string "NWES" for the \ mirror. Luckily, the lower two bits of the ASCII characters \ and / are 00 and 11 respectively, which is perfect to XOR with the aforementioned index to get the correct direction for the / mirror.
• Nice! You missed an obvious -1 byte, though: return"NWES"[...] (omit the space). Sep 4 '16 at 20:48
• Thanks Tim, it hadn't occured to me that that would be valid C :) Sep 5 '16 at 6:48
# CJam, 17 bytes
r"SWEN"_e!r'/#=er
Input is space-separated.
Try it online! (As a linefeed-separated test suite.)
This is the solution I found before posting the challenge. Not as short as Jonathan's cyclic indexing, but I thought this approach is quite interesting (and novel).
### Explanation
The goal is use transliteration (i.e. using a character-to-character mapping) to replace the input character with the output character. To do this, we need to select the correct map based on whether the mirror is / or \. We'll map from the SWEN list to another one which we'll select conditionally. If the input list is SWEN, the two output maps need to be the following:
in SWEN
/ ENSW
\ WSNE
Note that these are in sorted and reverse-sorted order (which is why we chose the seemingly random SWEN order as the input set). We could generate these by sorting the input list and the reversing the result if the input has \, but there's a better way:
"SWEN" e# Push input list for transliteration.
_e! e# Duplicate and get all permutations. The way, e! is implemented, it
e# always gives the permutations in sort order, regardless of the order
e# of the input set. Specifically that means that "ENSW" will be first
e# and "WSNE" will be last in this list.
'/# e# Find the index of / in this string. If the mirror is '/', then this
e# gives 0. Otherwise, this gives -1, indicating that '/' was not found.
= e# Select the corresponding permutation. Indexing is zero-based and
e# cyclic so that 0 (input '/') gives the first permutation "ENSW" and
e# -1 (input '\') gives the last permutation "WSNE".
er e# Perform the transliteration on the incoming direction.
e# Printing is implicit.
# SED 48 (42 + 1 for -r) 43
Saved 5 thanks to Martin Ender♦
s,N/|S\\,W,;s,E/|W\\,S,;s,N.|S/,E,;s,..,N,
Takes input as a two character string.
# Mathematica, 98 bytes
If[#2=="/",{"S",,,,,,,,,"W",,,,,"E",,,,"N"},{"N",,,,,,,,,"E",,,,,"W",,,,"S"}][[LetterNumber@#-4]]&
Anonymous function. Takes two strings as input and returns a string as output.
## C, 81 bytes
f(char*a){return a!="N/"&a!="S\\"?a!="N\\"&a!="S/"?a!="W\\"&a!="E/"?78:83:69:87;}
### Usage
main()
{
printf("N/ \t %c\n",f("N/"));
printf("N\\\t %c\n",f("N\\"));
printf("E/ \t %c\n",f("E/"));
printf("E\\\t %c\n",f("E\\"));
printf("S/ \t %c\n",f("S/"));
printf("S\\\t %c\n",f("S\\"));
printf("W/ \t %c\n",f("W/"));
printf("W\\\t %c\n",f("W\\"));
}
Output:
N/ : W
N\ : E
E/ : S
E\ : N
S/ : E
S\ : W
W/ : N
W\ : S
• Works only on hardcoded values since uses pointer comparisons. Sep 4 '16 at 19:33
# Pyth, 13 bytes
@."EW¹0`Y"sCM
Test suite
Sum the code points, modular index, compressed string.
# TI-Basic, 40 bytes
Hardcodes the inputs. Boring, but the shortest way.
sub("NEWS",1+int(inString("E/W\N\S/N/S\E\W/",Ans)/4),1 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4572334289550781, "perplexity": 6773.210299729209}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320301720.45/warc/CC-MAIN-20220120035934-20220120065934-00369.warc.gz"} |
https://www.allwords.com/statisitics-glossary-F-words-242-7-195.php | # All Words Glossary
Glossary of Statisitics Terms
beginning with letter F
Browse the Statisitics Glossary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
frequency
noun (frequenc, ies)
1. (uncountable) The rate of occurrence of anything; the relationship between incidence and time period.
• With growing confidence, the Viking"s raids increased in .
• The of bus service has been improved from 15 to 12 minutes.
1. (uncountable) The property of occurring often rather than infrequently.
• The FAQ addresses questions that come up with some .
• The of the visits was what annoyed him.
1. (countable) The quotient of the number of times $n$ a periodic phenomenon occurs over the time $t$ in which it occurs: $f = n / t$.
• The of middle C is 440 oscillations per second.
• The of a wave is its velocity $v$ divided by its wavelength $\lambda$: $f = v / \lambda$.
• Broadcasting live at a of 98.3 megahertz, we"re your rock alternative!
• The for electric power in the Americas is generally 60 Hz rather than 50.''
Browse the Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Find: Words Starting With: Words Ending With: Words Containing: Words That Match: Translate Into: Dutch French German Italian Spanish Show 51015202550100250500 results per page. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9327890872955322, "perplexity": 1472.2388936219004}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-10/segments/1581875149238.97/warc/CC-MAIN-20200229114448-20200229144448-00180.warc.gz"} |
http://math.bluecc.edu/parker/fraction-sums/index.html | # Fraction Sum Exploration
A common method for adding fractions is to find the lowest common multiple of the denominators. This is called the LCD algorithm, Lowest Common Denominator algorithm. Even though we have the smallest possible denominator that allows us to combine the fractions, sometimes the sum will still reduce. I have always wondered why.
Consider $$\frac{1}{3}+\frac{1}{6}$$. The LCD = 6, so the sum becomes $$\frac{2}{6}+\frac{1}{6}=\frac{3}{6}$$ or $$\frac{1}{2}$$. This is reducible.
Now consider $$\frac{1}{3}+\frac{1}{2}$$. The LCD = 6, so the sum becomes $$\frac{2}{6}+\frac{3}{6}=\frac{5}{6}$$. This is clearly not reducible.
I finally found an article explaining the theory behind when a fraction sum is reducible or irreducible. Please try our exploration tools before checking out number theory details.
Are you sure that you are ready?
Did you really some denominators first?
It's way more fun to explore first. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9169363379478455, "perplexity": 570.6850351640715}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818687642.30/warc/CC-MAIN-20170921044627-20170921064627-00547.warc.gz"} |
https://arxiv.org/abs/1608.03919 | Full-text links:
hep-th
(what is this?)
# Title:6d strings from new chiral gauge theories
Abstract: We study the 6d $\mathcal{N}=(1,0)$ superconformal field theory with smallest non-Higgsable gauge symmetry $SU(3)$. In particular, we propose new 2d gauge theory descriptions of its self-dual strings in the tensor branch. We use our gauge theories to compute the elliptic genera of the self-dual strings, which completely agree with the partial data known from topological strings. We further study the strings of the $(E_6,E_6)$ conformal matter by generalizing our 2d gauge theories. We also show that anomalies of all our gauge theories agree with the self-dual string anomalies computed by inflows from 6d.
Comments: 54 pages, no figures Subjects: High Energy Physics - Theory (hep-th) Report number: SNUTP16-002 Cite as: arXiv:1608.03919 [hep-th] (or arXiv:1608.03919v1 [hep-th] for this version)
## Submission history
From: Seok Kim [view email]
[v1] Fri, 12 Aug 2016 22:25:32 UTC (54 KB) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3135504722595215, "perplexity": 3508.7477245444948}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-13/segments/1552912204969.39/warc/CC-MAIN-20190326095131-20190326121131-00415.warc.gz"} |
https://onlinetesting-staging.americanbookcompany.com/sample/734 | North Carolina 5th Grade Math EOG - PreTest Calculator InActive
### North Carolina 5th Grade Math EOG - PreTest Calculator InActive Sample
Standard: 5.NBT.3 DOK: 2 1 pt
2.
Which symbol makes this sentence true?
Standard: 5.NBT.7 DOK: 2 1 pt
7.
What is the value of ?
Standard: 5.NF.7 DOK: 2 1 pt
15.
How many $\frac{1}{4}$ pound hamburgers can be made from a three-pound package of hamburger?
Standard: 5.NBT.5 DOK: 1 1 pt
19.
Amy spent 8 evenings putting together a puzzle. Each night, she put 125 pieces of a puzzle together. She finished the puzzle on the 8th night. How many pieces did Amy put together in all?
Standard: 5.NF.7 DOK: 3 1 pt
25.
The Sweetest Bakery uses 3 large bags of flour everyday. What fraction of a bag will be used in $\frac{1}{4}$ of a day? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 6, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6715338230133057, "perplexity": 11797.985588363488}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600402128649.98/warc/CC-MAIN-20200930204041-20200930234041-00750.warc.gz"} |
https://www.physicsforums.com/threads/gauss-words-knot-invariants.671286/ | # Gauss words, knot invariants
1. ### ArcanaNoir
757
We had a seminar on Gauss words yesterday, and the speaker brought up the fact that there are relatively few cases where the Gauss word could not be reduced to the trivial word. My question is, if the Gausss words can so often be reduced to the trivial word, how is that a good thing? At the least, how is that not a bad thing? Why do we even consider them?
2. ### I like Serena
6,194
Hey Arcana!
Gauss words... homotopy... differential geometry... (I had to look it up.)
Is this really general math?
3. ### ArcanaNoir
757
I didn't know where to put it. Knots are topology. Is that algebra? I wasn't sure. I guess algebra would be more appropriate.
4. ### I like Serena
6,194
I'd go for Topology & Geometry.
5. ### ArcanaNoir
757
Lol I wanted to put it in a topology sub forum but I didn't know we had one! I have all the other math sub forums on my homepage, I must have missed topology somehow. >_<
6. ### I like Serena
6,194
lol too. :)
Homepage? What kind of homepage?
7. ### ArcanaNoir
757
I just meant the "my pf" page.
8. ### I like Serena
6,194
I just looked, but there are no links to math sub forums there.
Did you hide them somewhere? ;)
9. ### ArcanaNoir
757
You have to go to the sub forum, then click forum tools, subscribe to this forum.
10. ### I like Serena
6,194
Aha! So you didn't subscribe to the topology sub forum I guess.
I hope you rectified that now. ;P
11. ### ArcanaNoir
757
Yes I have now happily corrected that oversight. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8193902373313904, "perplexity": 3937.0418945379747}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-35/segments/1440645328641.76/warc/CC-MAIN-20150827031528-00299-ip-10-171-96-226.ec2.internal.warc.gz"} |
https://www.arxiv-vanity.com/papers/1711.03044/ | arXiv Vanity renders academic papers from arXiv as responsive web pages so you don’t have to squint at a PDF. Read this paper on arXiv.org.
Lecture notes on Diagrammatic Monte Carlo for the Fröhlich polaron
J. Greitemann1, L. Pollet1*
1 Department of Physics and Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, Theresienstr. 37, 80333 Munich, Germany
* Lode.P
April 26, 2020
## Abstract
These notes are intended as a detailed discussion on how to implement the diagrammatic Monte Carlo method for a physical system which is technically simple and where it works extremely well, namely the Fröhlich polaron problem. They are not intended as a review on the physics of polarons, nor as a review of all problems where the method has been used. Sampling schemes for the Green function as well as the self-energy in the bare and skeleton (bold) expansion are disclosed in full detail. We discuss the Monte Carlo updates as well as techniques on how to perform the Fourier transforms for functions with discontinuities. Sample codes are made available online.
## 1 Introduction
These notes originate from a series of lectures taught at international summer schools intended for researchers interested in numerical methods and strongly correlated systems. They introduce the diagrammatic Monte Carlo (DiagMC) method, a quantum Monte Carlo method for strongly correlated systems in which one, simply put, samples over all Feynman diagrams. Feynman diagrams are versatile and employ a universal language used in high-energy as well as in condensed matter physics. DiagMC is one of the most promising methods still under active development to deal with generic fermionic models in high dimensions. The goal is to give an introduction and flavor of this method.
Prerequisities for a thorough understanding of this text are familiarity with the basics of quantum mechanics and elementary quantum field theory (notions such as the interaction picture, Wick’s theorem, Green function formalism, etc. ), statistical mechanics (partition function, solving two-level systems, etc.), and undergraduate computational physics (curve fitting, root solving, interpolation techniques, etc.) including classical Monte Carlo methods (notion of detailed balance, Markov chain Monte Carlo, Metropolis algorithm, etc.).
Let us summarize the main idea of the method, and how it differs from other quantum Monte Carlo schemes – admittedly, different researchers use the notion of diagrammatic Monte Carlo in quite different contexts. To this end, we must discuss the type of expansion, the sampling space, and the nature of the sampled series. Newcomers may skip the remainder of this paragraph in a first reading.
The starting point is a very general perturbative expansion of the form,
F(y)=∑n∑x1,…xnD(x1,…,xn;y). (1)
We compute a function depending on external coordinates (for example, the Green function with momentum and imaginary time ) which has a perturbative expansion. At every order there are internal coordinates (these are the internal momenta and imaginary times) which can be discrete or continuous, and are summed or integrated over. The different topologies have different kernels (cf. Fig. 5 below). The starting point in DiagMC is a weak coupling expansion, i.e., an expansion in the interaction. Let us decompose the Hamiltonian as where contains all one-body terms (and constitutes hence a quadratic Hamiltonian) and the interactions. Our basis states are the eigenstates of . Similar choices are made in (lattice) determinant Monte Carlo simulations for fermions, and in fermionic impurity solvers such CT-INT and CT-AUX (see Ref. [1] for a recent review). By contrast, a “strong-coupling” expansion is used in path-integral Monte Carlo simulations [2], in the worm algorithm [3] and the fermionic impurity solver CT-HYB [1]. In these schemes one perturbs in the kinetic hopping term whereas the solvable system (the potential energy term) is diagonal in the chosen Fock or real-space basis but not quadratic – it corresponds to the atomic limit.
An expansion of the partition function at inverse temperature and volume in the sense of a weak-coupling expansion and in the spirit of Eq. 1 reads
Z = Tre−βH=TrTτe−βH0exp[−∫β0dτH1(τ)] (2) = ∑k(−1)k∫β0dτ1…∫βτk−1dτkTr[e−βH0H1(τk)…H1(τ1)],
where in the second line we worked out the time-ordering operator of the first line. This expansion leads to nothing but a Taylor expansion in the interaction , namely with the coupling strength amplitude of and the coefficients that can be determined by evaluating all the integrals in Eq. 2 order by order, and which remain independent of . Methods such as lattice determinant Monte Carlo and the impurity solvers CT-INT and CT-AUX (but also the Monte Carlo methods referred to as strong-coupling expansions) evaluate physical quantities in thermodynamic equilibrium as
⟨Q⟩=TrQe−βHZ, (3)
and give it the following statistical meaning: Sample configurations are obtained, which are distributed according to the partition function with respective weights , and in which the quantity is evaluated. Hence,
⟨Q⟩=∑cQcpc∑cpc. (4)
The unbiased estimator for the expectation value of the quantity is then to sum up over all independent configurations and divide by the number of independent measurements. The normalization through the partition function is here manifest. As long as the system volume and its inverse temperature are finite, the Eq. 2 is an expansion in an entire function and hence always convergent (with the finiteness of the system we explicitly exclude all possible UV divergences that may still arise as e.g. in Sec. 8.2). The finiteness of the system ensures that no true spontaneous symmetry breaking can occur, which is at the heart of such methods as finite size scaling.
When physicists use the term DiagMC in the sense of the expression “sampling over all Feynman diagrams” it implies a number of differences compared to the previous paragraph: The thermodynamic limit is taken from the start, the partition function is usually not used for normalization (instead, the lowest order diagram is often chosen (see below)), nor does the sampling necessarily take place in the space of the partition function diagrams: The method (usually) relies on the cancellation of disconnected diagrams when computing correlation functions as can be found in standard textbooks [4, 5, 6, 7, 8]. This can equivalently be considered an expansion of the free energy .
These differences allow us to sketch some of the key properties of Feynman diagrams, which can be considered its advantages: All diagrams are topologically distinct and the magnitude of the prefactor is always 1 [6]. The language of Feynman diagrams is universal in all fields of physics. Feynman diagrams factorize over internal building blocks, such as particle propagators (single particle Green functions), interactions, and vertices. Consequently, the diagram weight also factorizes, which is a prerequisite for successfully developing a Markov chain Monte Carlo method. Analytical treatments of low orders or limiting cases can be built in analytically. In DiagMC one does not attempt to write down all diagrams explicitly (since the number of diagrams grows factorially with expansion order, this is only possible for the lowest expansion orders anyway) but one instead develops algorithmic rules that allow one to sample over all diagrams. This implies changing the internal integration variables, but also the topology and the expansion order. Non-perturbative features are accessible via skeleton series [9] and (partial) resummations of a certain class of diagrams. This takes us away from the bare expansion, and we will also see how this works for the Fröhlich polaron. In fact, any analytical treatment known from the literature can be built in. Ideally, the Monte Carlo sampling should only deal with featureless functions originating from high-dimensional integrals whereas any intricacy related to the field theory is dealt with analytically a priori.
The aforementioned differences bring us at the same time to the first main difficulty in the development of the DiagMC method, which is the series convergence: It is usually unknown whether a series converges or not. The series is guaranteed to diverge at a phase transition, but it may happen sooner. In fact, most series in physics are asymptotic, which can be established rigorously in a number of cases. A well known argument, first formulated in the context of quantum electrodynamics, is Dyson’s collapse argument [10]: When rotating the electric charge from to in the complex plane around the origin, one sees that the system is unstable to collapse (the potential energy scales quadratically with the number of particles, which is faster than the kinetic energy), rendering the convergence radius zero. The same holds for any interacting bosonic field theory: No matter how small in magnitude the attraction in the potential energy is, it beats the kinetic energy for large enough particle numbers, leading to a collapse. The asymptotic nature of the series can sometimes be dealt with using resummation methods [8], but, in general, the issue of a non-convergent series is an open problem and in our view the most difficult one that DiagMC faces.
The second main difficulty in the development of DiagMC is the sign problem, which prohibits us from finding the full solution [11]. Sign alternations are often inherent (and necessary) to the issue of convergence – without sign alternations the factorial growth in the number of diagrams could never lead to a meaningful result for an asymptotic series. Nor is the sign extensive in the system volume, as in path integral Monte Carlo simulations. Nevertheless, the sign problem puts in practice a limit on the expansion orders that can be reached. DiagMC features hence a tacit assumption that the sign problem is sufficiently weak such that sufficiently high expansion orders can be reached in order to extrapolate in a reliable way to infinite expansion orders (often in combination with a resummation scheme that is powerful enough). Unfortunately, this assumption can only a posteriori be checked.
The third difficulty is dealing with multi-dimensional objects such as a multi-legged vertex in the Bethe-Salpeter equation. Despite active research in the fields of self-adaptive grids and concise data storage formats, this is equally an unsolved problem. However, only in cases that an explicit expression for the whole object (or a high-dimensional subpart) is required (such as in self-consistency schemes) can this be considered a problem; otherwise one can just sample over such an object without ever evaluating it in full.
In these notes we consider a model where these three problems do not occur: the Fröhlich polaron model is sign-positive in the imaginary time formalism and the Green function convergent for all finite values of the imaginary time. Due to the rotational symmetry of free space can the Green function be stored as a two-dimensional object, which is easy to histogram and manipulate. There are other simplifying factors, which are related to the absence of vacuum polarization diagrams, or, equivalently, the observation that Feynman diagrams for polaron (and impurity) problems can be mapped onto path integrals (cf. the structure of a backbone line in Fig. 5 below). Indeed, the analytical properties of mesoscopic systems such as polarons and impurity systems appear to be much simpler than those of true many-body problems. Furthermore, for almost all problems of this type very accurate variational approaches (and wavefunctions) are known. The Fröhlich polaron is hence ideal to get acquainted with the DiagMC method. Not suprisingly, it was also the first model to which the method was applied 20 years ago [12, 13].
This text is structured as follows. After discussing perturbative expansions with continuous variables in Sec. 2, the main body of this text deals with the Fröhlich polaron problem, whose Green function is obtained from a bare expansion in Sec. 3, the self-energy from a bare expansion in Sec. 4 and from a bold expansion in Sec. 5. The source codes are made publicly available as discussed in Sec. 6. In Sec. 8 some related physical systems (of the polaron or impurity type) are listed where the acquired techniques can (and have been) applied without going into detail about the physics. For completeness, we mention that the method has also been successfully applied to a number of problems that cannot be considered of the polaron or impurity-type leading to deeper insight in notoriously hard problems. We mention resonant fermions [14, 15, 16], frustrated magnetism [17, 18, 19], and physics found in the Hubbard model [20, 21, 22, 23], among others.
## 2 Continuous-Time Monte Carlo
It is quite common to have discrete as well as continuous variables in quantum field theory. In this first section we explain, by means of the celebrated two-level system, how continuous variables and variable expansion orders can be dealt with in a Monte Carlo sampling. We employ the path integral representation here.
### 2.1 Model
Consider a two-level system with Hamiltonian,
H=H0+H1=hσz+Γσxh,Γ>0, (5)
where and are the usual Pauli matrices in the -basis with basis states and . The -field tries to orient the spin along the -axis which is countered by the -field which tries to orient the spin along the -axis. This system can be solved exactly, with the solutions (shown in Fig, 1)
⟨σx⟩ = −Γ√Γ2+h2tanh(β√Γ2+h2), ⟨σz⟩ = −h√Γ2+h2tanh(β√Γ2+h2), (6)
which makes this system a good model to get acquainted with continuous-time Monte Carlo. From the symmetry of the Hamiltonian we see that we can swap if we also swap .
### 2.2 Perturbative Expansion
Starting from the partition function
Z=Tre−βH=∑|α⟩=|↑⟩,|↓⟩⟨α∣∣e−β(Γσx+hσz)∣∣α⟩, (8)
we notice that the operator is diagonal in this basis. In order to prepare for a perturbative expansion in the term, we introduce the Heisenberg operators
σx(τ)=ehσzτσxe−hσzτ, (9)
and rewrite the partition function as
Z=∑|α⟩=|↑⟩,|↓⟩∞∑n=0(−Γ)nn!∫β0dτ1…∫β0dτn⟨α∣∣e−βhσzTτ[σx(τ1)…σx(τn)]∣∣α⟩. (10)
This is an explicit formulation of Eq. 2, .
To lowest order there are just 2 contributions, . Graphically, this can be depicted as a continuous worldline from to (see panel (a) in Fig. 2). We use a full line for spin-up and a dashed line for spin-down. Note that worldlines are continuous and periodic in because of the cyclical properties of the trace. For this reason, there are no non-zero contributions for , nor for any odd value of . This means that the term in Eq. 10 is always positive and we do not have to worry about a sign problem. In second order (see panel (b) in Fig. 2) we have
Z2=Γ2∑|α⟩=|↑⟩,|↓⟩|α1⟩=|↑⟩,|↓⟩∫β0dτ1∫τ10dτ2⟨α∣∣e−(β−τ1+τ2)hσzσx∣∣α1⟩⟨α1∣∣e−(τ1−τ2)hσzσx∣∣α⟩. (11)
Note that there is no factor of because it cancelled with the number of equivalent contributions from the time ordering operator and the corresponding changes in the time integration boundaries [6]. Although the higher order terms can be written in the same fashion, the integrals quickly become too complicated to evaluate explicitly. We therefore switch to a stochastic approach, for which it is easiest to think in terms of a graphical depiction, as shown in panel (c) of Fig. 2. To a vertex we attribute a factor , and to each segment of length (measured taking the periodic bounary conditions in into account) we attribute a weight with the sign depending on the spin state.
Analyzing the limiting cases, we expect to find, with almost equal probability, worldlines that are dominated by one of the spin states with few vertices at high temperatures. At low temperatures, we expect a dashed line with few kinks for , whereas for the spin wants to orient along the -direction, which graphically translates into having many vertices, and for which our chosen basis along the -direction is a poor choice. Our main task when designing a Monte Carlo scheme is hence to reach high expansion orders at low temperature with good efficiency.
There exist many equivalent ways to sample this system. The choice we make here resembles the updates later used in the Fröhlich polaron code, with similar design criteria. A minimal ergodic set of updates consists of the pair INSERT/REMOVE. If the INSERT update is chosen, we attempt to insert a new pair of vertices as shown in Fig. 3. We therefore select a random time chosen uniformly over . Looking in the direction of positive imaginary times, we determine the time interval counted from over which the spin occupation does not change. The second vertex is placed at a time chosen uniformly over the interval . For the reverse update, the pair to be removed consists of randomly selecting a vertex and taking the subsequent one in the direction of positive time. The weight in the old (i.e., before the INSERT update) configuration is , with the spin occupation at time in the old configuration. The weight in the new configuration is . With equal probabilities of selecting the INSERT and REMOVE updates, the probability factors are and with the number of vertices present in the old configuration. The update INSERT is accepted according to the Metropolis algorithm with probability where the acceptance factor is given by . For the REMOVE update the acceptance factor is . The differentials and enter the formulas for and as a consequenece of working with a continuous variable but they drop out in the acceptance factor .
### 2.4 Estimators
The observables of interest are the expectation value of the spin magnetization along the - and the -axis. There are two ways to measure the magnetization along the -axis (up to an irrelevant minus sign). The first one consists of evaluating the magnetization at a fixed time , which is an integer number. The second one evaluates the integral , which is a floating point number. Perhaps the reader thinks that the second way is far superior because it contains information from all times, but we will see that this is not true: the second way of measuring has only slightly lower error bars for the same runtime, whereas it is a considerably more expensive operation to perform, scaling linearly in the number of interaction vertices (even if done “on the fly” after every update). The magnetization along the -direction can be measured as as can be seen from Eq. 10. It is equally straightforward to obtain estimators for quantities such as , but we will not discuss this further.
### 2.5 Results
Let us start at low temperature with a strong magnetic field in the -direction. We take as parameters . After an initial thermalization phase of one million updates, we perform 10,000,000 updates, measuring after each one. After just a few seconds we see that we reproduce the exact result with error bars between and . The integrated autocorrelation times are about . We spend about of the time in the zeroth order diagram, and close to of the time in fourth order, although the code has occasionally gone to 16th order. So we sampled over quite a large Hilbert space and the code performed very well. There is no reason to optimize further.
At low temperature and strong magnetic field in the -direction ( and same runtime parameters as before) the autocorrelation times are also about . The error bars on are typically an order of magnitude smaller than in the case , which is explained by the fact that our basis is better suited. The error bars on are only slightly larger than before. In other words, the code is still behaving as expected.
At high temperature ( and same runtime parameters as before) the magnetization along either direction is about and hence very weak. Perhaps surprisingly, we see that the error bar on is of the order of , which is 50 times larger than the error bar on and one to two orders of magnitude larger than what we had at low temperatures – whereas low temperatures should be much more difficult to simulate. This is also reflected in the integrated autocorrelation times, which are about (it could well be worse because it is not clear if the code has converged) for the magnetization along the -axis and only along the -axis. Physically, the system has rotational symmetry in spin space, but this is clearly not respected in our updating procedure. As expected, the code spends of the time in the zeroth order diagram and the acceptance ratio for our INSERT-REMOVE updates is . What could be the reason for such bad autocorrelation times in an essentially non-interesting regime? The world-lines are of the time straight world-lines but the up and down orientations are almost equally probable because of the high temperature. Our current update scheme only allows one to change the orientation of the magnetization via the insertion of kinks, which is highly inefficient at high temperature. To cure this problem, we add another update SPIN-FLIP which, for simplicity, is only allowed in the zero-vertex sector and which attempts to swap between the up and down orientations of the spin. Adding this update cures the problem. It is good practice to keep the code as simple (and local) as possible, and to optimize or write extra updates only in case problems pop up.
With this we close the discussion on sampling continuous variables and different expansion orders and proceed to the main part.
## 3 Fröhlich polaron: Bare expansion for the Green function
The Fröhlich polaron problem describes the interaction between an itinerant electron and longitudinal, optical phonons. Historically, it was the first problem to which diagrammatic Monte Carlo was applied [12, 13, 24] for which it could provide definite answers regarding the polaron spectrum and arbitrarily precise polaron energies for any coupling strength. The Hamiltonian for a system in a volume is given by
H = Hel+Hph+Hel−ph Hel = ∑k(ℏk)22ma†kak, Hph = ∑qℏωqb†qbq=ℏωph∑qb†qbq, Hel−ph = ∑k,qV(q)(b†q−bq)a†k−qak, V(q) = iℏωphq(4παV)1/2(ℏ2mωph)1/4. (12)
The operators and are annihilation operators for electrons of mass with momentum and phonons with momentum , respectively. The phonon frequency can be taken momentum-independent for optical, longitudinal phonons. The dimensionless coupling constant is . Typical values for vary from for InSb over for CdTe to for AgCl (and are thus rather weak) [25]. We will work in units and take the continuum limit .
It is not the purpose of these notes to give an overview of the physics of the Fröhlich polaron, whose thermodynamics is now well understood (but questions remain for transport). We refer to the lecture notes by J. Devreese [25] for a pedagogical introduction. The basic competition in the model is between the electron kinetic energy trying to delocalize the particle and the phonons trying to localize it. The system can lower its energy by dressing the electron with phonons, resulting in the formation of a polaron. Its residue can be very low and the effective mass very high, but the polaron is never fully localized or fully self-trapped; there is hence no transition in this model.
For historical importance and to illustrate the connection with path integrals, let us remark that the Hamiltonian is quadratic in the phonon propagators, which can hence be integrated out. This results in a retarded one-particle propagator for the electron,
⟨0,0|0,β⟩=∫Dr(τ)exp[−12∫β0˙r(τ)2dτ+α23/2∫β0∫β0e−|τ−σ||r(τ)−r(σ)|dτdσ]. (13)
This path integral expression served as the basis of Feynman’s variational ansatz [26] which is remarkably accurate for the polaron energy for all coupling strengths. This path integral is, because of the retarded self-interaction, not as easy to simulate as the two-level system of the previous section, and will hence not be used for actual computations.
The structure of this section is as follows: We start with reviewing the necessary field-theoretical formulas to study quasi-particle properties, followed by the description of the algorithm used to simulate the polaronic Green function using a bare expansion. Next, we show some results that can be obtained with this code. In the following section the self-energy is computed using the bare expansion, with special emphasis on Fourier transforms and an illustration for the first order diagram. Finally, the bold expansion of the self-energy is introduced, again splitting the discussion between the first order diagram and higher order ones.
### 3.1 Digest of many-body theory
The central object of our analysis is the full single-particle Green function, which is related to the bare Green function and the self-energy via the Dyson equation as
(14)
For the polaron problem, we will work at zero temperature. To avoid instabilities due to poles, it is more convenient to work in imaginary time than with Matsubara frequencies in the sampling. For impurity problems, the bare Green function is just
G0(k,τ)=−θ(τ)e−(ϵk−μ)τ, (15)
with the Heaviside function, the dispersion, and an energy shift which is used as a tuning parameter (see below). In Matsubara representation the bare Green function takes the form
G0(k,ωn)=1iωn−(ϵk−μ). (16)
The quasi-particle energy and residue (which is the modulus squared of the overlap between the quasi-particle state and the free electron state) can be extracted from the large behavior of the full Green function,
G(k,τ)→−θ(τ)Zke−(Ek−μ)τforτ≫ω−1ph, (17)
which follows directly from the Lehman representation of the Green function. These quantities can also be extracted from the self-energy as
Ek = ϵk+∫∞0Σ(k,τ)e(Ek−μ)τdτ, (18) Zk = −∫∞0τΣ(k,τ)e(Ek−μ)τdτ. (19)
We will solve the problem of obtaining for fixed by diagrammatic Monte Carlo and are left with the task of finding such that the first equation is satisfied. This can be done by a root-solving algorithm in combination with one-dimensional integration. When is found self-consistently, the second equation determines the corresponding residue. The dispersion of the quasi-particle is given by analyzing as a function of .
### 3.2 Algorithm
The simplest way to solve the Fröhlich polaron problem is by considering the bare expansion of the full green function by using the expansion elements shown in Fig. 4. This was also presented in the original solution by Prokof’ev and Svistunov [12]. Wick’s theorem tells us that there can be no unpaired phonon creation and annihiliation operators, i.e., all phonon operators pair into ‘arcs’, the number of vertices is always even and in Eq. 12 only enters as a product with its complex conjugate. Graphically, the expansion is illustrated in Fig. 5. We can label the expansion order by counting the number of phonon propagators. In order there are phonon propagators, vertices and impurity Green functions. Our task consists of sampling over all possible diagrams for the bare Green function , i.e., sample over all possible expansion orders , all allowed topologies, and integrate over all internal momenta , and vertex times .
Every Feynman diagram is a valid Monte Carlo configuration, with a weight that factorizes into the product of the individual electron propagators , phonon propagators and vertices. It is convenient to absorb the vertex -factors into the phonon propagators and constants into the coupling constant , see Eq. 12 and our choice of units.
As an example, the full expression for the weight of the second order diagram with crossing phonon lines (one of the three possible topologies in second order) reads {fmffile}second_order
W(2)c(p,τ) (20) ×G0(p,τ1)G0(p1,τ2−τ1)G0(p2,τ3−τ2)G0(p3,τ4−τ3)G0(p,τ−τ4) ×~D(q1,τ3−τ1)~D(q2,τ4−τ2). (21)
Here and are the external momentum and time, respectively. The independent momenta are chosen as and , whereas , , and follow through momentum conservation. The factorization of the weight into bare Green functions and phonon propagators is now manifest. The extension of such explicit analytical formula’s to higher order is however cumbersome in comparison to drawing the Feynman diagrams.
We proceed therefore to how the diagrammatic Monte Carlo sampling can be performed. The updating scheme discussed below differs from the one introduced originally by Prokof’ev and Svistunov. Using the freedom which every designer of a Monte Carlo procedure has, we seek the simplest set of updates that is ergodic and remains as local as possible. By locality we mean that the number of changes to the current configuration is minimal and only involves one diagrammatic element plus its adjacent elements.
External variables – Because of the spherical symmetry of the Hamiltonian, we can choose the orientation of the external momentum to be along the -axis as , in which case the full Green function is a two-dimensional object in space. We can predefine a set of external momenta for which we compute . The simplest choice is a uniform grid, with where the momentum cutoff and the number of momentum points. Other choices for the grid are possible and perhaps even better because for low momenta we expect a dispersion akin to with the effective mass of the polaron, which suggests that a quadratic grid might be better. We will not go into further detail. The same procedure can be applied for the external time . Let us follow here another approach and consider to be a continuous coordinate between and , which we bin into a uniform grid of bin length at the expense of a small systematic discretization error if we use the discretized . A logarithmic grid might be a better choice given Eq. 17 (from experience we know that it does not really matter at this stage).
Normalization – We choose the zeroth order diagram for normalization, which is just the bare propagator . Because of the updates CHANGE-P and CHANGE-TAU (see below) the total normalization integral is . All quantities in the Monte Carlo sampling can be normalized by multiplying with where counts how often we are in the zeroth order diagram. This can be seen as follows: The estimator for the normalization diagram is
⟨δnorm⟩MC∝∑{pj}∫τmax0G0(pj,τ)dτ. (22)
The estimator for the full Green function is
⟨EG(pj,τi)⟩MC∝δτ∈biniδpj,pk, (23)
where we used that and all residing in the bin are taken together in entry (it is possible to improve on this by computing the ratio , although there is seldomly a need for that). The proportionality constant drops out when normalizing
G(pj,τi)=⟨EG(pj,τi)⟩MC⟨δnorm⟩MCN/Δτi, (24)
with the volume of the time-bin . The same can be done for other quantities of interest such as the bare Green function and the first order Green function.
CHANGE-P – This update is only allowed if the expansion order is 0. In this update, which is its own reverse, we uniformly select a new from the set of allowed external momenta and accept it according to the Metropolis algorithm as with acceptance factor . We can also opt to keep the external momentum fixed in a single run.
CHANGE-TAU – This update is only allowed if the expansion order is 0. In this update, which is its own reverse, we select a new external time using an exponential distribution. If the dispersion is with the external momentum and a random number uniformly chosen between , then we construct and accept it as the new external time of the diagram if .
INSERT – This update attempts to increase the number of phonon propagators by one (its reverse is REMOVE, see below and Fig. 6) and is constructed as follows: Select a random electron propagator and identify its left and right endpoints. Let us call this propagator . Select with uniform probability a time , which serves as the time of the left vertex of the new phonon propagator. The time is obtained as with chosen uniformly. If the update is rejected. The three components of the momentum are obtained from the Box-Müller algortihm as a gaussian random number with mean 0 and variance . The acceptance factor is given by where stands for the old configuration and for the new one, for their respective weights, and for their a priori transition probabilities. They are given by
W(X) = G0(k,τR−τL), W(Y) = ~α2G0(k,τ1−τL)G0(k,τR−τ2)G0(k−q,τ2−τ1) ×~D(q,τ2−τ1)dτ1dτ2d3q(2π)3, P(X→Y) = pINSdτ1τR−τLωphe−ωph(τ2−τ1)dτ2e−q22m(τ2−τ1)d3q(2πm/(τ2−τ1))3/2, P(Y→X) = pREM1Narcs+1. (25)
Here, and are the probabilities to select the INSERT and REMOVE probabilities, respectively. Note in particular that all differentials cancel in the acceptance factor . The reader notices that further cancellations occur in the acceptance factor such as the electron propagators between and , as well as any -dependence. Those cancellations are only exact if function calls are used; for tabulated objects in combination with interpolation techniques there are tiny deviations from these cancellations.
REMOVE – This is the reverse update of INSERT. We uniformly select a phonon arc and check if its vertices are consecutive elements in the time ordered confiugration (see above). If this is not the case, the update is rejected. The acceptance factor is the inverse of the one determined above for the INSERT update.
SWAP – The INSERT and the REMOVE update allow to change the expansion order but are insufficient to generate all possible topologies because they do not allow phonon arcs to cross. The SWAP update allows one to change the topology wihtin a given expansion order . With the notation of Fig. 7 we randomly select a vertex excluding the last one. If it has a time and the next one a time , we attempt to swap the end points of their respective phonon propagators. In order to conserve momentum at every vertex, the momentum of the electron propagator between and changes – in line with our design criterion of finding updates that are local. The acceptance factor is given by with and .
EXTEND – Although this update is not needed for ergodicity, it is a useful one to improve the sampling. It changes the duration of the rightmost electron propagator in a similar fashion as the CHANGE-TAU update.
### 3.3 Implementation
The number of diagrams grows as . Only the lowest expansion orders can be evaluated explicitly, but the Monte Carlo algorithm manages to sample over the most important contributions in any order. The parameter requires some finetuning: Its magnitude needs to be sufficiently large such that the full Green function decays exponentially. The closer is chosen to the unknown polaron energy (i.e., ) the less rapid this decay will be and the more accurate the fit (cf. Eq. 17) can be performed. For sufficiently strong , and chosen closely to , the expansion order can be 100 or more.
Other authors prefer the use of a cyclical implementation [13] instead of a backbone line. The aim is to treat the electrons and the phonons on equal footing. It is also the structure that naturally arises at finite temperature. At zero temperature, we see little advantages for polaron problems and have not used cyclical diagrams in our codes.
### 3.4 Data structure
Let us now discuss the data structure. There are various equivalent ways to store the diagram. E.g., one may either (i) store the intervals between the emission and absorption of a single phonon along with its momentum, or (ii) one opts to store the vertices. We choose the latter approach. The necessary information needed to specify a vertex are its time, a pointer (or iterator in case of standard-library (STL) containers) to the vertex that it connects to via the phonon propagator, the phonon momentum and at least one of the phonon and electron momenta interacting at the vertex such that all momenta can be inferred from momentum conservation. If we choose, say, to store the phonon momenta, all electron momenta in the diagram can be computed from the given external electron momentum and by invoking momentum conservation at every vertex, but this is obviously a costly operation scaling linearly with the number of vertices. In the present implementation we decided to store all three momenta at each vertex for locality reasons, efficiency, and added readability. A configuration is then specified by a time-ordered collection of such vertex objects.
When choosing the data structure, one should be conscious of the operations required by the update scheme and their respective complexity. Obviously, the ability to INSERT and REMOVE vertices efficiently while retaining the time ordering as well as the ability to seek forward and backward along the electronic backbone line are crucial, thus ruling out plain contiguous array-like data structures. Likewise, the INSERT update needs to randomly pick an electron backbone segment, the REMOVE update randomly picks a phonon propagator, and the SWAP update randomly selects a pair of adjacent vertices. All three of these ultimately draw a vertex uniformly from the set of all vertices (or in case of SWAP from all but one).
We implemented a number of different data structures to meet these requirements to varying degrees and gauge their impact.
1. A doubly-linked list as provided in by std::list satisfies the first criterion with insertion and removal but requires one to start at the beginning and iterate through the list to reach a randomly picked vertex, thus resulting in scaling (with the number of vertices).
2. A self-balancing binary search tree, e.g. an AVL or red-black tree, provides insertion and removal and in principle also allows for true random access of an ordered sequence in when nodes keep track of the number of nodes in their subtrees. Search trees will automatically enforce ordering which we however do not benefit from as the update scheme is designed in a way that retains time ordering anyway. While std::map is usually implemented in terms of binary search trees, it cannot be used off-the-shelf here as it hides its tree implementation and does not allow for the kind of additional bookkeeping required to achieve fast random access. For testing, we implemented an AVL search tree with a function to randomly access elements by index.
3. A doubly-linked list may be combined with a contiguously stored array (a std::vector) of iterators to the list elements that serves as a lookup table. Upon insertion, an iterator to the newly created list element is pushed to the back of the array. The list element is likewise tagged with the index of its iterator in the array. When removing a list element, its iterator in the array swaps places with the last one (updating the tag of its list element) before it is popped. This procedure retains the complexity of insertion and removal operations and keeps an up-to-date array containing iterators to all the list elements contiguously, albeit not in time order. Thus, we do not get proper random access but gained the ability to pick a random element in . Care has to be taken when applying this to the SWAP update.
The performance impact of the choice of data structure depends on the average order that is reached in the course of the simulation which in turn depends on the system parameters. In our benchmark, Fig. 8, we decided to keep fixed and vary the chemical potential to probe a number of mean expansion orders.
In situations where the average order was below 10, the search tree (implemented as an AVL tree) performed badly compared to the list-based data structures due to the added overhead. It would only become a feasible alternative outperforming the plain list when orders beyond 40 were reached as can be seen from Fig. 8. In contrast, the list-array combination barely shows any scaling with the diagram order and was consistently faster than the plain list indicating that the overhead added due to the lookup array is very light. For models with a sign problem where only low expansion orders can be reached, it does not matter how the data structure is implemented.
### 3.5 Error bars
The estimation of the error bars on the Green function is complicated by the fact that the normalization itself is estimated from the same simulation. We employ the jackknife resampling technique to account for that. This requires knowledge of the time series. Sampling after every single update would result in excessive memory demand and post-processing time due to many highly-correlated samples and negate the efficiency of the local update scheme. Thus, we group updates into bunches of elementary updates. After each elementary update, we increment histograms for the Green function, the zeroth order counter used for normalization, etc. After elementary updates, the histograms are measured, i.e. recorded in the time series, and subsequently reset. The choice of can be guided by the estimated autocorrelation time obtained from a binning analysis.
Within the framework provided by the ALPSCore library (cf. Sec. 6), we can rely on the FullBinningAccumulator to perform the above binning analysis for us. Further, any derived quantities calculated from the observables are automatically resampled using the Jackknife method.
### 3.6 Results
For , and a runtime of about 1 minute on a single core laptop one can extract the polaron energy with an accuracy better than a percent. Stronger couplings are a little bit harder to simulate: We show the Green function for , and zero momentum in Fig. (a)a. By fitting the exponential tail according to Eq. 17, one can extract the polaron energy () and residue (). Here, the fit took data from onwards into account. However, for the Green function decays rather quickly. This limits the maximum time that can be accessed with reasonable accuracy. Additionally, when taking the error bars into account in the fit, the data close to impact the fit more strongly due to their higher accuracy. This leads to a heightened sensitivity towards systematic errors from the non-asymptotic fast initial decay with respect to the choice of .
In order to get a more reliable estimate of the polaron energy, we tuned the chemical potential to achieve longer imaginary times along with a less severe growth of the error bars. Choosing (Fig. (b)b), was accessible, allowing us to probe the asymptotic regime over time scales many times that of the initial fast decay. The inset in Fig. (b)b displays results for the polaron energy estimated from fits with different . This has been done for the data from each of the 28 independent MPI processes to yield an error on that estimate. It can be seen that after an initial influence from the non-asymptotic onset, the results beyond stay consistent within their error bars. Our final result reads and . The polaron energy was thus found with a relative accuracy of at modest computational effort.
The polaron energy is remarkably close to the value predicted by Feynman’s variational ansatz despite the rather strong coupling . Feynman’s trial action is parametrized by parameters and , the latter of which was assumed to have only a mild influence on the end result [26]. Feynman then optimized for at fixed , treating parts of the integrals approximately. From the expressions he gave in the strong-coupling regime, we find (for ) and (for ). With today’s readily available numerical integration and optimization tools, we also optimized for and simultaneously without taking any approximations to the integrals. This results in an improved variational energy of (, ). Thus, our Monte Carlo estimate is lower, in accordance with the variational principle.
The dispersion for is shown in Fig. 10. In this calculation we recalculated one of the first hallmarks of DiagMC [12]. It shows that the perturbative result incorrectly predicts an endpoint to the dispersion, whereas the DiagMC results show that the binding energy can be seen up to zero energy. In passing we note that other formula for the computation of the effective mass and the group velocity exist, see Ref. [13, 24]. The histogram over the expansion orders for is shown in Fig. 11. For large enough expansion orders , decays exponentially. The acceptance factors are about for INSERT and REMOVE and for SWAP. Those numbers are acceptible. If deemed too low, or if the frequency of visiting the normalization diagram is too low, reweighting and flat histogram techniques should be used.
## 4 Fröhlich polaron: Self-Energy
It is often advantageous to compute the self-energy instead of the full Green function and resort to the Dyson equation (Eq. 14) to obtain the latter. However, a Fourier transform from imaginary times to (Matsubara) frequencies is needed to cast the Dyson equation in algebraic form; otherwise, it is a convolution. Below we first discuss how to perform such Fourier transforms by considering the first order diagram, and then proceed with the diagrammatic Monte Carlo computation of the full self-energy. In this text, the self-energy is always understood as the one-particle irreducible self-energy [5].
### 4.1 Fourier Transforms explained for the first order self-energy
The first order self-energy is shown in Fig. 12 together with the Green function related to this diagram via the Dyson equation. The first order self-energy can be computed analytically for zero external momentum,
Σ(1)(p=0,τ)=−~α2√2m4π3/2√τe−(ωph−μ)τ. (26)
When applying Eq. 18 and using a root solver, we find that the polaron energy is given by for in our units. The first order self-energy for non-zero external momenta can be computed as,
Σ(1)(p≠0,τ) = −~α2e−(ωph−μ)τp(m2πτ)3/2∫∞0drsin(pr)e−mr22t (27) = −~α2e−(ωph−μ)τp(m2πτ)3/2(2τm)1/2F(p√τ2m),
where is the Dawson function, . For small values of the argument, it behaves as . For large values of , it behaves as . This formula for is the Fourier transform of the self-energy in real space , with
G0(r,τ)=−θ(τ)(m2πτ)3/2e−mr22τ+μτ, (28)
and
~D(r,τ)=~α2e−ωphτ4πr, (29)
which can be seen as a retarded Coulombic-like potential.
In principle, all we need to do is apply the Dyson equation (Eq. 14) and Fourier transform back to the imaginary time domain. However, as we will see, this must be done very carefully.
Shape of the self-energy – The most important observation is that the self-energy diverges as for for any . This is in fact quite a common situation in continuous space, originating from the momentum integral over the bare electron Green function. The first order self-energy very often has limits that need to be analyzed analytically. Is this divergence a problem? On the one hand, any integral is convergent; in particular, there is no problem with the existence of a proper Fourier transform. On the other hand, a Taylor expansion of the self-energy around the middle of the -bin shows that the binning process has uncontrollable systematic error bars for sufficiently small values of . The solution is not difficult: One can choose to refrain from sampling and compute the self-energy analytically for fixed, discrete values, thereby circumventing the binning issue. If this is not an option and sampling remains essential, then one should make a measurement of , which is a featureless function of . Whenever the discretized is needed, it is obtained from . Unfortunately, this is not the only problem associated with the divergence as we will see in the discussion on the Fourier transforms.
Fourier transforms – One of the most fundamental differences between classical mechanics and quantum mechanics is the occurrence of non-commuting operators in the latter, which in turn leads to the time ordering inherent to quantum field theory. This is already apparent from the Heaviside function in Eq. 15. It has the following frequency representation
θ(t)=∫∞−∞dωeiωtω−i0+dω. (30)
It is this behavior which explains the structure in Eq. 16. Note that the coefficient of the term in Eq. 16 is exactly 1 (which is identical to the jump in the Green function for and ) thanks to the (anti-)commutation relations of bosonic (fermionic) annihilation and creation operators [5]. Therefore, the same asymptotic behavior holds not only for but for any Green function . In the inverse Fourier transform , brute force summing (or integrating) over all frequencies in the hope of restoring the Heaviside function is hopeless. One therefore needs to treat the large-frequency tails carefully. At finite temperature, Fourier transforms assume that the function can be periodically continued, which is likewise violated. The easiest solution is to (i) only use the analytic formulations Eq. 15 and Eq. 16 for the bare Green function, and (ii) never perform a Fourier transform on any full Green function but only on differences . In doing so, the leading asymptotic frequencies are compensated as well as the discontinuity in imaginary time taken care of. It is also possible to treat the in the same fashion: Its coefficient in frequency space corresponds to the (sum of the) slope(s) of the Green function at (and ) in imaginary time.
In the literature one can also find formulas for the term, but we have never seen a case where this is necessary for the success of the calculation.
When we rely explicitly on the jump being 1 in between and , we need to make sure in the Monte Carlo sampling that we choose large enough such that since by construction we have . As we have seen before, this means that must be quite large when is chosen close to the polaron energy . The region where is sizable may well appear smaller than this. Let us now use the imaginary-time and Matsubara formalisms for the Fourier transforms; specifically,
Σ(p,ωn) = (31) δG(p,τ) = 1βn=∞∑n=−∞δG(p,ωn)e−iωnτ, (32)
with the Matsubara frequencies for bosons and for fermions. A single electron has no statistics; we can use either bosonic or fermionic ferquencies, or just – it should not matter as long as we use a transformation that turns the Dyson equation into an algebraic equation. From the Dyson equation can be written as
δG(p,ωn)=G0(p,ωn)Σ(p,ωn)G0(p,ωn)1−G0(p,ωn)Σ(p,ωn). (33)
Observing the decay of over many decades (as a function of ) requires in turn a huge number of Matsubara frequencies. The naive implementation of the Fourier transform scales as where is the number of points in the time/frequency domain and becomes too costly. Although alternative approaches exist [27], let us explain here how fast Fourier transforms (FFT) can be used, with a scaling as . For simplicity and efficiency, we rely on the open source package FFTW [28]. Although our input data is real (impyling that ) and we could use the function calls r2c and c2r (cf. the FFTW documentation; we could save a factor 2 in storage) we consider this advantage negligible and use instead the easier function call dft for complex input and output. At this point the reader should keep in mind that FFT is only a tool for solving the equations Eq. 31 and Eq. 32. It performs
Yk = N−1∑j=0Xje−i2πjk/N, Xj = N−1∑k=0Ykei2πjk/N, (34)
between input data and output data , and this is not identical to Eqs. 31 and 32. Recall what FFT really computes (cf. the FFTW documentation): first, the phase used in the forward (backward) Fourier transform corresponds to the backward (forward) sign convention in Eqs. 31 and 32; second, the forward transform immediately followed by the backward transform multiplies the input by ; and third, the positive frequencies are stored in the first half of the output and the negative frequencies are stored in backwards order in the second half of the output.
FFT assumes an equidistant grid where the input data are located exactly on the grid points. If we need more Matsubara frequencies than we have grid points in imaginary time, or if we use a non-uniform grid, we need interpolation methods. In practice, quadratic or spline interpolation is used. After binning the data for the self-energy, we have discretized values (in order to avoid the same has to be done with Eq. 26); i.e., we do not have the self-energy evaluated precisely on the grid points as FFT requires. If we choose bosonic Matsubara frequencies , then this problem does not pop up for the frequencies. Dropping the diagonal momentum index to make the notation lighter, the discretized form of Eq. 31 reads
Σ[n]=N−1∑j=0ΔτΣ[j]ei2πnβ(j+1/2)Δτ, (35)
with . This is almost identical to what FFT can compute for us: Apart from multiplying the input with (the integration measure), the output self-energy of the FFT must be multiplied by for each positive frequency , and by for each negative frequency . This operation needs to be undone when (and we should not forget the factor ). In case of fermionic Matsubara frequencies, a similar phase multiplication on the data in the time domain can be derived (we leave the exact phase as an exercise).
The Green function corresponding to the first order self-energy at zero momentum is shown in Fig. 13. We see that the required number of Matsubara frequencies is prohibitively large before agreement with the bare result is found; i.e., the systematic error of the truncation in Matsubara frequencies dominates over the statistical error of the unbiased Monte Carlo sampling of the bare Green function. The reason is that the nasty divergence of the first order self-energy leads by dimensional arguments to a behavior, which decays even slower than a Green function for large frequencies. One could treat this divergence analytically (eg, by Taylor expanding the self-energy), or pursue the following approach: First, notice that the divergence in Eq. 27 is to leading order independent of the momentum (and hence identical to the result). Second, notice from the Dyson equation Eq. 33 that it suffices to compute corresponding to the convolution in imaginary time and which hence behaves as for . This cures the divergence but still has a divergent slope: When binning data over the sampled continuous variable we should still measure , as mentioned before. Before performing the Fourier transform, we subtract
δΣ(p,τ)=Σ(p,τ)−Σ(p=0,τ), (36)
and compute analytically the convolution
ζ(p,τ):=(Σ(p=0)⋆G0(p))(τ)=−~α2√m(2π)3 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8840524554252625, "perplexity": 530.5146061199029}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593657181335.85/warc/CC-MAIN-20200716021527-20200716051527-00571.warc.gz"} |
http://math.stackexchange.com/questions/100055/proof-of-lh%c3%b4pitals-rule-that-minimizes-special-casing | # proof of l'Hôpital's rule that minimizes special-casing
A simple form of l'Hôpital's rule looks like this: If $u$ and $v$ are functions with $u(0)=0$ and $v(0)=0$, the derivatives $\dot{v}(0)$ and $\dot{v}(0)$ are defined, and the derivative $\dot{v}(0)\ne 0$, then \begin{align*} \lim_{x\rightarrow 0} \frac{u}{v} &= \frac{\dot{u}(0)}{\dot{v}(0)} \qquad . \end{align*}
To me, the clearest way to arrive at this result uses a little nonstandard analysis: Since $u(0)=0$, and the derivative $d u/d x$ is defined at $0$, $u(d x)=d u$ is infinitesimal, and likewise for $v$. By the definition of the limit, the limit is the standard part of \begin{equation*} \frac{u}{v} = \frac{d u}{d v} = \frac{d u/d x}{d v/d x} \qquad , \end{equation*} where by assumption the numerator and denominator are both defined (and finite, because the derivative is defined in terms of the standard part). The standard part of a quotient like $p/q$ equals the quotient of the standard parts, provided that both $p$ and $q$ are finite (which we've established), and $q \ne 0$ (which is true by assumption). But the standard part of $d u/d x$ is the definition of the derivative $\dot{u}$, and likewise for $d v/d x$, so this establishes the result.
The generalizations to $x\rightarrow a$, where $a\ne 0$, and $x\rightarrow \infty$ are pretty trivial with the changes of variable $x\rightarrow x-a$ and $x\rightarrow 1/x$.
But there are a bunch of other cases of l'Hôpital's that seem to me to involve toxic doses of case-splitting. There are cases where you have to differentiate more than once, and cases where the indeterminate form is $\infty/\infty$ rather than $0/0$.
Is it possible to treat all of this in a unified way, possibly using ideas from projective geometry or inversions with respect to a circle in the complex plane?
-
The case where you differentiate more than once follows from the case where you differentiate once, by induction. I think the case $\infty / \infty$ follows by the $0/0$ case by letting $f(x)/g(x) = (1/g(x))/(1/f(x))$ and go back to a $0/0$ case. When you differentiate this new case, you get $$\lim_{x \to 0} \frac{1/g(x)}{1/f(x)} = \lim_{x \to 0} \frac{ -g'(x)/g(x)^2 }{ -f'(x)/f(x)^2 } = \lim_{x \to 0} \frac{f(x)^2/g(x)^2}{f'(x)/g'(x)}.$$ I've tried to figure out the logic of it, but I'm a little tired (this is my second "tired" post today... gosh, no energy) maybe you can complete my arg. – Patrick Da Silva Jan 18 '12 at 4:53
@PatrickDaSilva: Thanks for your comment. I'm sure there is an inductive proof of then nth-derivative case, but I don't think the most obvious method of induction works. One of the hypotheses of l'Hôpital's rule is that $\dot{v}\ne 0$, which fails in the cases where you need multiple differentiation. I think an NSA-style approach works, since the Leibniz notation $d^2u/dx^2$ can be taken as essentially a literal division of two infinitesimal numbers. It's not so much that I can't find proofs in books or on the web, it's that there seems to be more need for case-splitting than I'd like. – Ben Crowell Jan 18 '12 at 5:41
@PatrickDaSilva: Your $(1/g)/(1/f)$ idea seems to work nicely. It requires lots of uses of $\lim(ab)=\lim a \lim b$ and $\lim(a/b)=\lim a/\lim b$, which may create some complication in the case where $\lim b=0$, or in the case where you want to use l'Hopital's rule to prove that a limit doesn't exist. – Ben Crowell Jan 18 '12 at 16:32
You're a fan of non-standard analysis huh? It sure does make proofs seem cleaner, but it takes a lot of work to understand why it works. I hope you've read stuff about it. – Patrick Da Silva Jan 18 '12 at 16:33
@Ben Crowell: Danger! It is not possible to use l'Hôpital's rule to prove that a limit does not exist!! See e.g. the example on page 4 of math.uga.edu/~pete/2400diffmisc.pdf. – Pete L. Clark Jan 18 '12 at 17:37
Last week I covered L'Hôpital's Rule in my Spivak Calculus course. I ended up preferring the proof given in Rudin's Principles to Spivak's treatment, because (i) he does compile several different cases in a rather efficient way and (ii) he proves a stronger result in the case where $\lim_{x \rightarrow a} g(x) = \infty$, namely that there is no hypothesis needed on the limiting behavior of the numerator $f$.
I wrote this up in $\S$ 1 of these notes. However I must confess that I found the proof itself not very interesting and ended up not covering it in class.
I must also confess that I don't really understand the OP's sketch proof. In particular I do not recognize the hypothesis $g'(a) \neq 0$ that the OP is assuming: who says that $f$ and $g$ are even defined at $a$? I am also slightly skeptical that NSA really helps here to give a shorter proof, but I would be very interested to be proven wrong about this.
Added: If you are willing to assume that $f$ and $g$ are defined and differentiable at $a$, that $f(a) = g(a) = 0$ and that $g'(a) \neq 0$, the proof becomes almost trivial:
$\lim_{x \rightarrow a} \frac{f(x)}{g(x)} = \lim_{x \rightarrow a} \frac{f(x) - f(a)}{g(x)-g(a)} = \lim_{x \rightarrow a} \frac{ \frac{f(x)-f(a)}{x-a}}{\frac{g(x)-g(a)}{x-a}} = \frac{ \lim_{x \rightarrow a} \frac{f(x) - f(a)}{x-a}}{\lim_{x \rightarrow a} \frac{g(x)-g(a)}{x-a}} = \frac{f'(a)}{g'(a)}$.
(However this version is inadequate for many of the standard applications of freshman calculus.) So I presume we're talking about a stronger version than this?
-
If one’s willing to prove only the $0/0$ case, and that only in the special case when $f\,'(a)$ and $g'(a)$ exist, it really is possible to give a very short NSA proof; Jerry Keisler does it about three lines in his Elementary Calculus, using the OP’s argument with more detailed notation. – Brian M. Scott Jan 18 '12 at 7:35
@Brian: Thanks for that information. I think though that by making the extra hypotheses you suggest the standard proof becomes essentially a three line calculation as well...What do you think? (Hmm, maybe for the easy proof I also want to assume $f'$ and $g'$ are continuous at $a$.) – Pete L. Clark Jan 18 '12 at 13:19
It’s six of one, half a dozen of the other for that result, though the NSA version of the argument may be just a hair more intuitive. Some of the basic theorems really are a bit more straightforward in the NSA version, but I’d not say that this was really one of them. – Brian M. Scott Jan 18 '12 at 13:55
I see. The stronger form $\lim f/g=\lim f'/g'$ allows proof by induction for the nth-derivative case, whereas my weaker form $\lim f/g=f'/g'$ doesn't. In a), Step 1, I assume you really mean $-\infty<A<\infty$, not just $A<\infty$? And is b) meant to be the case where $A=\pm\infty$? There does seem to be a big cost in complexity for the stronger form. You're quantifying over five variables, with quantifiers three deep. I guess the $b=\pm\infty$ case is handled properly by a) Step 1, since $b$ occurs only in $\ldots<b$ and in limits, so there is no assumption that $b$ is real. – Ben Crowell Jan 18 '12 at 16:09
@Ben: No, I really mean what I wrote (which is the same as what Rudin wrote). If $A = -\infty$, we still need to bound the quotient from above. Also, doesn't every statement of the form $\lim_{x \rightarrow a} f(x) = L$ involve three quantifiers? – Pete L. Clark Jan 18 '12 at 17:23 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9661211967468262, "perplexity": 240.6348564248396}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-18/segments/1461860123845.65/warc/CC-MAIN-20160428161523-00055-ip-10-239-7-51.ec2.internal.warc.gz"} |
http://mathhelpforum.com/advanced-applied-math/15211-central-force-problem.html | # Math Help - Central force problem
1. ## Central force problem
Central force F=-ar/(r^3) & Central potential energy,U=-(a/r)
(not U_eff)
Find the nature of orbits if (i)a>0 and (ii)a<0
If we remember the attractive central force E=E(r) diagram,i.e.the one showing the graph of U_eff,we only need to know E_total=K+U.
Where only PE is given.
We see,
U= -integration[F.dr]=integration[dW]=-integration[dK]=-K
Then K=a/r and U=-(a/r)
So,the E=K+U=0
Then in positive and negative both caes we get a parabolic orbit.
Please check if i am correct.
2. Originally Posted by kolahalb
Central force F=-ar/(r^3) & Central potential energy,U=-(a/r)
(not U_eff)
Find the nature of orbits if (i)a>0 and (ii)a<0
If we remember the attractive central force E=E(r) diagram,i.e.the one showing the graph of U_eff,we only need to know E_total=K+U.
Where only PE is given.
We see,
U= -integration[F.dr]=integration[dW]=-integration[dK]=-K
Then K=a/r and U=-(a/r)
So,the E=K+U=0
Then in positive and negative both caes we get a parabolic orbit.
Please check if i am correct.
That's one possibility...
Doesn't the form of the force law look familiar? That should lead you to what the correct answer should be. Now you have to prove it.
-Dan
3. There is the problem.The -ve force obviously corresponds to elliptical path...
But I am getting total energy 0.
But I annot understand where did I go wrong?
4. OK,thank you.I got it.
Consider a>0.
Then, -(m(v^2)/r)=-(a/r^2)
or,m(v^2)=(a/r)
Hence total energy E=K+U= -(1/2)(a/r)
=>elliptic orbit.
Consider a<0.
Then,F=+b/r where b=-a>0
and U_p=b/r
K is itrinsically positive.So,total energy positive.
From e=sqrt[1+{(2L^2*E)/(m*b^2)}]
e>1.
hence hyperbolic trajectory. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.962665855884552, "perplexity": 11462.945711219936}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1430456438489.42/warc/CC-MAIN-20150501050038-00084-ip-10-235-10-82.ec2.internal.warc.gz"} |
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# Calling all Kelley (Indiana) 2013 Applicants!
Author Message
Manager
Joined: 24 Nov 2012
Posts: 59
Concentration: Finance
GMAT 1: 740 Q45 V47
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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16 Mar 2013, 11:09
PatBateman wrote:
UTMPA2011 wrote:
Does that mean full ride? So you going to Kelley then?
= $50k scholarship and$34.5k GA position. I was not expecting that. I have a tough decision to make now.
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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18 Mar 2013, 07:49
Hi! I received an admit to Olin WUSTL and Kelley with NO scholarship. Which one should I take? Which one is the best?Olin is 7K more expensive than Kelley. But WUSTL is private and Indiana public. I'll appreciate your thoughts on that. Thanks!
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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18 Mar 2013, 07:53
1
KUDOS
There is a lot of variables that are involved with that decision: Specifically what are you trying to study/concentrate in?
All is else being equal I would go with Kelley.
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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18 Mar 2013, 08:03
Thanks golfer42. I am leaning towards Finance, but interested in CPG too. Additionally, I have no problem on building a post-MBA career in the mid-west.
Manager
Joined: 29 Nov 2012
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Concentration: Marketing, Strategy
Schools: Kelley (Indiana) - Class of 2015
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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18 Mar 2013, 08:38
1
KUDOS
kolin wrote:
Thanks golfer42. I am leaning towards Finance, but interested in CPG too. Additionally, I have no problem on building a post-MBA career in the mid-west.
If Finance/CPG are your interests, I'd definitely choose Kelley.
Manager
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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18 Mar 2013, 10:25
Just received my admit pack. 50k +34K GA. I think they have convinced me too. I am giving up the 30k scholarship at Olin and will be matriculating at Kelley this fall. I hope someone deserving gets my seat and $at Olin. Manager Joined: 29 Nov 2012 Posts: 123 Location: Canada Concentration: Marketing, Strategy Schools: Kelley (Indiana) - Class of 2015 GMAT 1: 720 Q49 V40 GPA: 3.5 WE: Operations (Non-Profit and Government) Followers: 2 Kudos [?]: 38 [0], given: 23 Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink] ### Show Tags 18 Mar 2013, 11:39 Just got my admit package...$ scholarship + \$34k GA position. Chuffed to bits!
Last edited by jxcho on 18 Mar 2013, 18:51, edited 1 time in total.
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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18 Mar 2013, 18:49
Got the package today. Seems like the standard 50k+34kGA. Have a question though- if someone can answer. I am an international student. However, I have been living and working in Indiana for the past two years? Do i have to pay Indiana resident fees or Non-resident fees? Appreciate your reply.
Manager
Joined: 29 Nov 2012
Posts: 123
Concentration: Marketing, Strategy
Schools: Kelley (Indiana) - Class of 2015
GMAT 1: 720 Q49 V40
GPA: 3.5
WE: Operations (Non-Profit and Government)
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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18 Mar 2013, 18:55
boothcornellrock wrote:
Got the package today. Seems like the standard 50k+34kGA. Have a question - if someone can answer. I am an international student but have been living and working in Indiana for past two years? Do i pay Indiana resident fees or Non-resident fees? Appreciate your reply.
Do you have a green card? Some states allow students in H1B status to get resident tuition (e.g. NY) but most require you to have a green card before being eligible for resident tuition. (and you'd have to trade in H1B for F1 to attend B-school F/T anyway)
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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18 Mar 2013, 19:09
jxcho wrote:
boothcornellrock wrote:
Got the package today. Seems like the standard 50k+34kGA. Have a question - if someone can answer. I am an international student but have been living and working in Indiana for past two years? Do i pay Indiana resident fees or Non-resident fees? Appreciate your reply.
Do you have a green card? Some states allow students in H1B status to get resident tuition (e.g. NY) but most require you to have a green card before being eligible for resident tuition. (and you'd have to trade in H1B for F1 to attend B-school F/T anyway)
Thanks much! That was quick. I do not have a green card neither am i on H1. Guess i will have to shell out some money despite a generous package.
Intern
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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19 Mar 2013, 23:02
20K + 34k GA... confused between Olin and Kelley... the loan product + 30k schol that Olin offered is very tempting ... moreover the college has shown progressive improvement in rankings and placements
Manager
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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19 Mar 2013, 23:42
20K + 34k GA... confused between Olin and Kelley... the loan product + 30k schol that Olin offered is very tempting ... moreover the college has shown progressive improvement in rankings and placements
Washington University is regarded more highly than Indiana, but as far as business school is concerned, Kelley > Olin. (Don't go just by 1 ranking, US rankings 2013)
There are so many factors.
1. Class size : You can have a relatively bigger class size and a larger alumni network at Kelley.
2. Cost: Olin is marginally costlier than Kelley
3. Schol : You have a better offer at Kelley.
4. Teaching method/curriculum: Kelley has academies/majors/minors, Olin not much!
5. Ultimately, it depends on your career goals too. Kelley is strong in Accounting, marketing, entrepreneurship and supply-chain. Dont know much about olin though.
Even I had to forego the 30k at olin for kelley. Hope that helps!
Manager
Joined: 29 Nov 2012
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Concentration: Marketing, Strategy
Schools: Kelley (Indiana) - Class of 2015
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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20 Mar 2013, 01:01
zpotm wrote:
5. Ultimately, it depends on your career goals too. Kelley is strong in Accounting, marketing, entrepreneurship and supply-chain. Dont know much about olin though.
Don' t forget social enterprise/sustainability at Kelley as well... they offer a Social Entrepreneurship certificate as part of the MBA in conjunction with IU SPEA, one of the best public admin/nonprofit/environmental policy schools in the country.
Intern
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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20 Mar 2013, 18:25
Are you guys able to create the New ID? It seems like my name is still not updated.
Intern
Joined: 27 Jul 2012
Posts: 19
Concentration: Organizational Behavior, Human Resources
GMAT Date: 10-13-2012
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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28 Mar 2013, 15:14
I'm in at Kelley! How long did it take everyone to receive their admissions packets/fellowship offers? A little over a week?
Manager
Joined: 29 Nov 2012
Posts: 123
Concentration: Marketing, Strategy
Schools: Kelley (Indiana) - Class of 2015
GMAT 1: 720 Q49 V40
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Kudos [?]: 38 [0], given: 23
Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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28 Mar 2013, 15:43
kettlered wrote:
I'm in at Kelley! How long did it take everyone to receive their admissions packets/fellowship offers? A little over a week?
Are you a R3 applicant? IIRC it took most people in R2 4-9 days to get their packet.
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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30 Mar 2013, 09:54
Hi all! I'm a graduating second year at Kelley. For those accepting I wanted to reach out as I will be renting my house. If you're interested please email me and I can fill you in with details, and if interested, show you the home during experience weekend/day.
Thanks!
Jon
jonritch@indiana.edu
Intern
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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30 Mar 2013, 19:44
In at Kelley and Matriculating!
Intern
Joined: 25 Aug 2012
Posts: 17
Concentration: Finance
Schools: Kelley '15 (A)
WE: Asset Management (Other)
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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02 Apr 2013, 08:55
1
KUDOS
MBKULOV wrote:
In at Kelley and Matriculating!
Congrats! I put down my deposit yesterday.
Intern
Joined: 22 Feb 2012
Posts: 15
Concentration: Entrepreneurship, Marketing
GMAT 1: 660 Q45 V36
GMAT 2: 660 Q42 V39
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Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink]
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03 Apr 2013, 20:29
1
KUDOS
Admitted with a hefty scholarship and coming out to Experience weekend next week. I was completely sold on Kelley and was days away from submitting my deposit, however, I earlier today I got admitted to USC (No news on financial aid yet). Though I doubt that USC will match the offer that I received from Indiana, I was born, raised, and currently live in Los Angeles. I'm specifically interested in Entrepreneurship, so the financial freedom post MBA would be very liberating, however, I'm having a hard time decided between the two. Anyone have any useful advice in selecting between the two?
Re: Calling all Kelley (Indiana) 2013 Applicants! [#permalink] 03 Apr 2013, 20:29
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Display posts from previous: Sort by | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3303932845592499, "perplexity": 23758.24547667394}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-26/segments/1466783400572.45/warc/CC-MAIN-20160624155000-00017-ip-10-164-35-72.ec2.internal.warc.gz"} |
http://mathematica.stackexchange.com/questions/33538/numerical-solution-of-coupled-odes-with-boundary-conditions | # Numerical solution of coupled ODEs with boundary conditions
I have to solve the following set of ODEs and just can't get good results using Mathematica $$r\frac{d}{dr}\left(\frac{1}{r}\frac{d}{dr}A(r)\right)-\xi^2F(r)^2\left(A(r)-1\right)=0$$ $$\frac{1}{r}\frac{d}{dr}\left(r\frac{d}{dr}F(r)\right)-\frac{n^2}{r^2}F(r)\left(A(r)-1\right)^2-\frac{1}{2}F(r)\left(F(r)^2-1\right)=0$$ There are two parameters $\xi\in\mathbb{R}^+$ and $n\in\mathbb{Z}$. There also are boundary conditions at $0$ and at $\infty$. $$F(0)=A(0)=0$$ $$F(\infty)=A(\infty)=1$$ These gave me the first puzzle: how to implement boundary conditions at infinity? I solved this by taking a finite number (in my case 5) instead of infinity. Do you think it is a good approach or is there a more elegant way to implement boundary conditions both at zero and infinity?
Next I want to solve these equations numerically. Here is the Mathematica code for $\xi=1$ and $n=1$
paramND = {
r D[1/r D[A[r], r], r] - \[Xi]^2 F[r]^2 (A[r] - 1) == 0,
1/r D[r D[F[r], r], r] - n^2/r^2 F [r] (A[r] - 1)^2 -
1/2 F[r] (F[r]^2 - 1) == 0,
A[5] == 0.99, A[0.01] == 0,
F[5] == 0.99, F[0.01] == 0} /. {\[Xi] -> 1, n -> 1};
numSol = NDSolve[paramND, {A[r], F[r]}, {r, 0.01, 5}] // Flatten;
paramPlot = {A[r], F[r]} //. numSol;
Plot[Evaluate@paramPlot, {r, 0.01, 5}, PlotRange -> {0, 1},
PlotStyle -> {{Black, Thick}, {Red, Thick}},
PlotLegends -> {"A(r)", "F(r)"}]
For $\xi=1$ and $n=1$ this works fine and I get a result that I expect:
The problem is that the numerical solution only works if both parameters $\xi$ and $n$ are close to $1$. Changing these parameters to values different from $1$ produces somewhat awkwrd results:
$\xi=3$, $n=1$:
$\xi=1$, $n=5$:
As you can see, the last two plots don't even respect the boundary conditions! Why is this so? All solutions should look more or less like the first plot, which clearly isn't the case.
I suppose that I lack some fundamental knowledge about how to use NDSolve to produce results which I expect. Can you suggest a good strategy in order to obtain good solutions to these ODEs? I've also tried using the "Shooting" algorithm, which, however, didn't give any useful result either. Maybe you can point out to me what the exact reason is, why NDSolve fails here so I know what to cure. Up to now it was rather a try and error procedure.
So, to sum up, my two questions are:
1. How to implement boundary conditions at infinity?
2. How to choose a good strategy for NDSolve to obtain results one expects?
-
I have tried to solve ur sys for the specific values you mentioned with maple and the output is accurate. – MMM Oct 13 '13 at 3:09
(2) Compactification
Update
Ok, my original post was rather compact. Let us start from the begining. You functions $A$ and $F$ map $[0,∞)$ into the reals. But you can think of the preimage as the result of another bijective function that maps say $[0,1)$ into $[0,∞)$. Since the domain of that second function can be easily modified to include $1$, the compound function will have its domain (at least formally) compactified. The question is: how is it done in Mathematica.
Let us use $r=ArcTanh(ρ)$ as the compactifying function.
Plot[ArcTanh[x], {x, 0, 1}, PlotRange -> All]
Define $B(ρ)=A(r(ρ))$ and $G(ρ)=F(r(ρ))$. That is, the functions $B$ and $G$ are the functions $A$ and $F$ "in $ρ$-space".
The following code shows how to go from $r$ space into $ρ$ space and back:
{F[r], F'[r], F''[r]} /. F -> Function[{x}, G[Tanh[x]]] /. r -> ArcTanh[\[Rho]]
% /. G -> Function[{x}, F[ArcTanh[x]]] /. ρ -> Tanh[r] // FullSimplify[#, Assumptions -> r \[Element] Reals] &
{G[ρ], (1 - ρ^2) G'[ρ], -2 ρ (1 - ρ^2) G'[ρ] + (1 - ρ^2)^2 (G'')[ρ]}
{F[r], F'[r], (F'')[r]}
The above code basically computes $\frac{d F}{ d r}$ as $\frac{d G}{ d ρ} \frac{d ρ}{ d r}$ and a similar formula for $F''(r)$ in terms of $ρ$. You might want to check those results by hand to convince yourself of the replacements done in the differential equations:
eq = {r D[1/r D[A[r], r], r] - ξ^2 F[r]^2 (A[r] - 1) == 0,
1/r D[r D[F[r], r], r] - n^2/r^2 F[r] (A[r] - 1)^2 -
1/2 F[r] (F[r]^2 - 1) == 0} /. {
F -> Function[{x}, G[Tanh[x]]],
A -> Function[{x}, B[Tanh[x]]]
} /. r -> ArcTanh[ρ] // FullSimplify[#, Assumptions -> ρ \[Element] Reals] &
Similarly, the boundary conditions become
bc = {A[5] == 0.99, A[0.01] == 0, F[5] == 0.99, F[0.01] == 0} /. {
F -> Function[{x}, G[Tanh[x]]],
A -> Function[{x}, B[Tanh[x]]]
} // N
{B[0.999909] == 0.99, B[0.00999967] == 0., G[0.999909] == 0.99, G[0.00999967] == 0.}
The next modifications of your code are:
hNumSol = NDSolve[Flatten[{
eq /. {ξ -> 1, n -> 1},
bc
}], {B, G}, {ρ, Tanh[.001], Tanh[5]}] // Flatten;
hParamPlot = {B[Tanh[r]], G[Tanh[r]]} //. hNumSol;
If you then plot
Plot[Evaluate@hParamPlot, {r, .01, 5}, PlotRange -> All,
PlotStyle -> {{Blue, Thick}, {Green, Thick}},
PlotLegends -> {"A(r)", "F(r)"}]
you will obtain exactly the same graph as in your question.
So far, we have reproduced your calculation but we have used $ρ$-space. In order to impose boundary conditions at infinity, impose them at $ρ=1$:
max = 1;
bc = {B[max] == 0.99, B[0.001] == 0., G[max] == 0.99, G[0.001] == 0};
hNumSol = NDSolve[Flatten[{eq /. {ξ -> 1, n -> 1}, bc}], {B, G},
{ρ, 0.001, max}] // Flatten;
The new plot misbehaves even though ξ=1 and n=1:
Therefore, your problem is not due the inability to impose the boundary conditions at infinity. A solution worth exploring is to change the functions for which you are solving.
-
I do not have time to work the solution, but now that you have the equations in ρ-space, find the $p$ and $q$ such that the $b$ defined by $B(ρ) = ρ + ρ^p (1-ρ)^q b(q)$ is a function that stays finite (and non-zero) at $ρ=0$ and $ρ=1$. Repeat for $g$ in $G(ρ) = ρ + ρ^s (1-ρ)^t g(ρ)$. Once you got the boundary behavior out of the way, get the differential equations in terms of $b$ and $g$. Try to solve those. – Hector Oct 13 '13 at 0:38
Well, as @Hector has shown that your bvp has no issue for choosing finite value at the far field condition (infinity). The problem here is with your parameters values. Suppose, your bvp is in dimensionless form then you are free to choose whatever value you want for the parameters involved. But in your case, you not that lucky to do so. The best way will be to find a way, to select a specific domain for each parameter for which the bvp has a stable solution. – MMM Oct 13 '13 at 0:48
Thanks @Hector for teaching me how to implement compactification in Mathematica, it's very useful, and answers entirely my first question. As you both Hector and MMM mentioned, the inability to find a correction numerical solution is caused by the numerical instability of the ODEs depending on the chosen parameters. Hector, you're suggesting to rewrite the ODEs in terms of $b(\rho)$ and $g(\rho)$, could you maybe comment on how you arrived at this specific ansatz? – Stan Oct 13 '13 at 20:53
@MMM I didn' t quite understand what you meant by dimensionlessness in this contest, in my case all variables are dimensionless. – Stan Oct 13 '13 at 20:54
@Stan In ρ-space, the boundary conditions for $B$ are $B(0)=0$, $B(1)=1$. Those are taken care of by the first addend in the ansatz. The leftover should be function that vanishes at both boundaries. The real guess is that the behavior of that vanishing is of the form $ρ^p$ and $(1-ρ)^q$. The next step is to assume that $b(ρ)$ has a Taylor expansion around $ρ=0$. Replace that into your ODE and you could get $p$. – Hector Oct 14 '13 at 15:53 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4811515808105469, "perplexity": 1212.4738262926369}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-06/segments/1422122238694.20/warc/CC-MAIN-20150124175718-00057-ip-10-180-212-252.ec2.internal.warc.gz"} |
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0043352 | Research Article
# Growth Dynamics Explain the Development of Spatiotemporal Burst Activity of Young Cultured Neuronal Networks in Detail
• Affiliation: Neural Engineering Department, Institute for Biomedical Engineering MIRA, University of Twente, Enschede, The Netherlands
X
• Affiliation: Neural Engineering Department, Institute for Biomedical Engineering MIRA, University of Twente, Enschede, The Netherlands
X
• w.l.c.rutten@utwente.nl
Affiliation: Neural Engineering Department, Institute for Biomedical Engineering MIRA, University of Twente, Enschede, The Netherlands
X
• Published: September 19, 2012
• DOI: 10.1371/journal.pone.0043352
## Abstract
A typical property of isolated cultured neuronal networks of dissociated rat cortical cells is synchronized spiking, called bursting, starting about one week after plating, when the dissociated cells have sufficiently sent out their neurites and formed enough synaptic connections. This paper is the third in a series of three on simulation models of cultured networks. Our two previous studies [26], [27] have shown that random recurrent network activity models generate intra- and inter-bursting patterns similar to experimental data. The networks were noise or pacemaker-driven and had Izhikevich-neuronal elements with only short-term plastic (STP) synapses (so, no long-term potentiation, LTP, or depression, LTD, was included). However, elevated pre-phases (burst leaders) and after-phases of burst main shapes, that usually arise during the development of the network, were not yet simulated in sufficient detail. This lack of detail may be due to the fact that the random models completely missed network topology .and a growth model. Therefore, the present paper adds, for the first time, a growth model to the activity model, to give the network a time dependent topology and to explain burst shapes in more detail. Again, without LTP or LTD mechanisms. The integrated growth-activity model yielded realistic bursting patterns. The automatic adjustment of various mutually interdependent network parameters is one of the major advantages of our current approach. Spatio-temporal bursting activity was validated against experiment. Depending on network size, wave reverberation mechanisms were seen along the network boundaries, which may explain the generation of phases of elevated firing before and after the main phase of the burst shape.In summary, the results show that adding topology and growth explain burst shapes in great detail and suggest that young networks still lack/do not need LTP or LTD mechanisms.
### Introduction
Studies on developmental changes in biological neuronal networks may advance our understanding of brain development, activity patterns associated to different stages, or the relationship between connectivity and activity. Long-term cultured networks of dissociated rat cortical neurons provide a useful experimental platform for this study [1], [2], [3], [4], [5], [6], [7]. On a relatively long time scale, from several weeks to months in vitro, neuronal cultures undergo major morphological changes in neurite outgrowth and connectivity/topology, with a corresponding impact on activity. Particularly in the first 3 weeks growth is probably a major factor to determine connectivity, whereas at later stages long term plasticity mechanisms may become dominant. A profound feature of activity in cultured cortical networks is bursting; i.e. synchronized firing at an elevated frequency in a large part of the network.
This paper is the third in a series of three on simulation models of cultured networks. Our two previous studies [26], [27] have shown that random recurrent network activity models generate intra- and inter- bursting patterns similar to experimental data. The networks were noise or pacemaker-driven and had Izikevitch-neuronal elements with only short-term plastic (STP) synapses (so, no long-term plasticity, LTP or LTD, included). However, elevated pre-phases (burst leaders) and after-phases of burst main shapes were not yet explained in sufficient detail. This lack of detail may be due to the fact that the random models completely missed network topology and also lacked a growth model, which is essential to study how activity develops with time. The present study adds topology and growth and thereby combines neurite growth models and electrical activity models to predict synchronous bursting behavior, their spatial spread (burst waves) as well as their longitudinal development.
Of course, LTP and LTD mechanisms are widely accepted as essential mechanisms in developing and learning neuronal systems and have been studied experimentally also in cultured networks, as pioneered by Jimbo and co-workers (see [7] for an review], although with limited success. Long term plasticity mechanisms may also largely determine the development of activity patterns, in particular at later developmental stages. However, it remains unclear to what extend the factor growth contributes to the development of network connectivity, in young cultures.
Experimental studies give us a variety of observations ranging from the basic morphological structures of typical cortical neurons like interneurons and pyramidal cells [6], [8], [9] to more specific structures like those of large GABA-ergic interneurons [10]. Analysis of basic cell structures and their growth led to the design of models of neuronal morphogenesis [11], [12] which can be used to build a simulation framework for generating realistic wiring topologies [13], [14]; cell numbers are usually rather limited (for example, N = 62 in [15]). Meanwhile, investigation of more specific neurons underlined their key role in network electrophysiological activity. For example, Voigt et al. [10] showed that large GABA-ergic cells with characteristic extensive neurite arborization and high synaptic density around their somas can drive synchronous oscillatory activity in immature cultured networks (it is to be noted that young GABA-ergic cells start their life as excitatory cells). On the other hand, network topology directly influences network firing. For example, Kitano et al. [16] showed that a network's small-world topology can generate clustered spiking (bursting), where random networks cannot, when using the same electrophysiological parameters. These results suggest that realistic topologies should be implemented into simulations of spiking activity.
A variety of models exist to generate neurite structures (for review see [17]). The focus can be on neurite guidance [18], [19] or on structure formation of the neuritic trees [11], [12]. So far, these aspects have not yet been combined. For example, the generic model of chemotactic based network self-wiring in [19] did not include neurite branching, whereas the model of dendritic outgrowth by Van Pelt and Uylings [12] did not take into account neurite bundling and neurite steering by guidance cues. All these features are critical for the proper formation of synaptic connections in the network, thereby affecting network electrical activity.
In this report we will build a wiring topology for networks of up to 50,000 neurons, using the model of neuronal morphogenesis by Van Pelt and Uylings [12]. Subsequently, this wiring layout is used as the connectivity matrix in a network model to generate spiking activity. As an extension, we will add the neurite guidance model by Segev and Ben-Jacob [19] to mimic axono-somatic targeting. Finally, to both models we will add a set of fast growing interneurons to mimic large GABA-ergic neurons. Together, this leads to four model variants. Simulation results will be characterized as much as possible by the same intra- & inter- burst parameters as used before in our experimental studies, for comparison and evaluation of models with experimental data. Networks will be followed until 22 days in vitro (DIV). The automatic adjustment of various mutually interdependent network parameters is one of the major advantages of our current approach.
The purpose of the model is to show how axono-somatic targeted-growth networks develop into consistently repetitive burst producing systems, as observed in experiment. With burst characterization both in time (burst shapes; burst rhythms) and in space (burst propagation, burst “waves”), with variable network size. The model also will enable to investigate propagation of bursts along the network boundaries (reverberation effects), in the spatial domain as well in its temporal utterance in the pre- and after-phases of burst shapes. As such, it will also contribute to answer the important general question to what extend growth may explain recorded activity patterns during the first 3 weeks in sufficient detail.
### Methods
#### Simulation of network morphology
In the present study we proceeded on the research by Van Pelt and Uylings [12] who developed a stochastic approach for neurite outgrowth models. In further research Koene et al. [13] used their ideas to simulate network topologies and observe network development. Their modeled structures for cell types containing both cortical pyramidal neurons and interneurons as well as their development in time, were successfully compared with experimental data, e.g. [12], [20]. We used their validated functions of neurite elongation and branching rates as well as their model parameter values, so that all simulated neurites grew at the same rates as in cultured cortical neurons. For the time development of the network topology we used a time step of 1 day, as from experiment it is known that neurites do branch not more than once a day [12].
We designed circular networks, incorporating 10,000–50,000 neurons with homogeneous (uniform) density of about 2500 neurons per mm2. The average radius of these virtual cultures varied from about 1.1 to 2.5 mm. We assumed that somas adhere firmly to the substrate. The neurites grew planarly and were allowed to cross each other. We used a triangular lattice (of 85,000 to 433,000 lattice cells) in a circular area to randomly arrange neurons. Every soma was represented by a stationary (not moving) unit occupying one of the lattice cells. Circular shaped somas, with radius 6.25 µm, were placed in the center of a lattice cells with random shifts of ±5 µm. We took m = 20 µm for the edge length of the lattice, yielding only small overlap for excentrically placed cells with a neighbor (if present, see inset of figure 1). Neurite outgrowth always remained within the predefined circular space (unless mentioned otherwise).
We employed two models of growth, random and chemotaxis-guided. The random modele (Koene et al. [13]) identified the direction vector of the neurite outgrowth as the sum of vectors preceding it plus a random perturbation (ra) which was drawn from a uniform distribution over the interval [amin, amax]. The guided one applied a chemotactic neurite navigation approach presented by Segev and Ben-Jacob [19] to calculate the final direction of axonal outgrowth. From the first day in vitro (DIV) plated neurons (somas) release chemo-attractive cues guiding axonal outgrowth. Growth cones sense a gradient of guidance cues and alter their direction in the next simulation step. Instead of random perturbation (ra) we calculated the directional derivative of the soma concentration over all the local neurons yr within a circular searching area with radius dx,y, set equal to the axonal elongation Δl. Here g satisfied the following diffusion equation:. Taking into account the cytoskeleton rigidity and membrane tension structure in a consolidated axon we also defined the same bounds [amin, amax] for . If there were no neurons within the local searching area (g(yr) = 0), axons did not change direction but continued growing in the same direction.
The two approaches described above will be referred to as randomly growing and field -guided networks, respectively. On the first virtual day in vitro (vDIV) axons elongated with random perturbations in both approaches. Starting from the second vDIV, axons extended towards higher spatial somatic concentrations in field-guided networks Then from the 3rd vDIV, growing axons coming across dendrites defined the set of ‘candidate synaptic connections’. The successful synapses were randomly chosen from all the temporal candidates at every subsequent vDIV with a probability of 0.05. This probability was chosen to adjust the number of generated synapses per neuron to the experimental range [21].
For transmission delays we adopted the results from a modeling study by Manor et al. [22]. They considered simple cases where the geometrical ratio of neurites (i.e. axons) was always equal (set to 1), meaning that the sum of the diameters of the daughter branches was the same as the diameter of the parent branch. Action potentials traveled with a constant velocity of 540 µm/ms in the root branch. With this propagation speed, the axonal delay for an axonal length of about 3.5 mm on vDIV 21 corresponded to an average propagation delay of 6.5 ms. According to [22], these axonal delays make up about 72% of the total delay. The remaining 28% was added to account for the synaptic and dendritic delays (fixed at 2.5 ms). These values were confirmed in two other experimental studies using cultured cortical networks [23], [24].
To obtain initial values for absolute synaptic weights we followed a study by Williams and Stuart [25] who investigated how post-synaptic potentials depended on the distance from the soma to the location of the synapse on the dendrites. They found that the amplitude of somatic post-synaptic potentials decreased with the distance to the soma. We implemented their finding by defining synaptic strengths with an initial PSP height of 1 mV, that linearly decreased with the distance to the soma by a factor 0.0025/µm. As most network parameters now directly depended on the topology structure, we did not have to set them manually, like we did in previous models [26], [27]. Thus, axons contributed to transmission delays only, whereas dendrites also contributed to somatic post-synaptic potential attenuation.
#### Characterization of the network topology
To analyze structural properties of the simulated network topology we calculated the characteristic path length (L) and the clustering coefficient (C) introduced by Watts and Strogatz [28]. lij between two neurons is defined as a minimum number of synapses through which the action potential has to travel to get from one neuron to another. ci indicates the number of connections between all neurons connected to chosen neuron i as a fraction of the maximum possible number of such connections. It is defined as:(1)
where ki is the degree of neuron i (i.e. number of synaptic connections with different neurons) and Ei is the number of connections of neuron i. L and C are calculated as the averages of lij and ci, respectively. (This was possible only for networks of 10,000 neurons because of computational limitations.). To acquire statistical description of the generated topological structures we employed a quantitative measure of ‘small-world-ness’ (S) introduced by Humphries and Gurney [29]: First, using the analytical approximation by Newman et al. [30] we estimated the average Lrand and Crand for (Poisson) random graphs with the same number of neurons (nodes, n) and average number of connections per neuron (average degree, <k>) as in simulated networks.(2)
(3)
Then S was calculated as following:(4)
At the end of each vDIV (corresponding to realistic neurite outgrowth observed on one day in neuronal culture [12], [20]) the connectivity matrix was built out of all successful synapses. This matrix entered the spiking model which then simulated 1 hour of spiking activity.
#### Simulation of spiking activity
To simulate the firing activity we employed the (pulse-coupled) spiking neural network model as described in [26], [27]. The system of equations that networks generate can be presented in the following way:(5)
where(6)
Here, xi is the firing pattern of a receiving neuron i, dt is the simulation step and xj(t -dij) represents the state of a transmitting neuron j (i,j = 1, 2,… n, where n is the total number of neurons). Synaptic noise, independent for different i's is presented by Ji. In our simulations each neuron received a Poissonian spike train (J) of rectangular 1 ms pulses, with a mean rate of 80 Hz and with an amplitude normally distributed between 0 and 8 mV, as described in [26], [27]. The variable vi(t) characterizes the dynamics of the neuronal membrane potential, as described by Izhikevich [31]; eij = −1 for inhibitory neurons and +1 for excitatory neurons. dij is the total transmission delay that incorporates axonal synaptic and dendritic propagation latencies as described before. wij is the momentary synaptic weight obtained from the phenomenological model for short-term plasticity [32]. Parameter values for the Izhikevich neuronal models were set randomly (using a normal distribution, see [26]) in ranges taken from [31], such that our networks contained 3 types of excitatory neurons (80% of total, including regular spiking, intrinsically bursting and chattering neurons) and two inhibitory types (including fast spiking and low-threshold spiking interneurons). We applied parameter values obtained by Gupta, Markram et al [32], [33] to describe the phenomenological synaptic model of short-term plasticity. These were the same as used before (for a summary see Appendix S1).
In this study, we focused on the effect of network topology and its development on the resulting activity patterns. We used a set of neuronal parameters that adequately reproduced the dynamics of cortical neurons [31]. This set contained a mixture of all neuronal cell types that exist in the cortex, which gave our simulations a certain degree of robustness against variations of cell properties. However, it should be noted that our results might be affected by changes in cell properties. Simulations of network spiking activity were implemented in C, using Euler's forward method for numerical integration of differential equations with a simulation time step of 1 ms.
#### Characterization of bursting activity
To validate the simulated data against experiment, the layout of 60 micro-electrode arrays (MEAs, see under Cultured networks) was mapped onto the network topological space to pick up spiking activity around their virtual electrodes. To obtain a robust set of data, we used 100 of such mappings for each simulation. Network bursts were calculated as the total firing rate (firings at all virtual electrodes summed) from the mapped array as is also done for experimental recordings [2]. We also used their burst definition i.e. a burst was detected when two or more spikes were detected for each active virtual electrode (with spike rate >0.1 Hz) within 10 ms bins. Burst profiles were smoothed using a Gaussian filter with 5 ms. Maximal Firing Rate (mFr) is the firing rate at the peak of the burst profile. Inter-burst intervals (IBIs) were calculated as the time intervals between peaks of neighboring bursts. A superburst was defined as a series of bursts with IBIs ≤1 s.
In addition, we will present spike raster plots showing all simulated neurons. We applied a (counter-clockwise) spiral order for neuronal indexing, such that low index neurons were at the center of the network.
#### Cultured networks
Experimental techniques such as culturing and recording are explained in detail in [2]. In short, MEAs had 60 Titanium-Nitride electrodes (with 30 µm diameter) in an 8 by 8 square grid with 200 µm electrode spacing. MEAs were coated with poly-ethylene-imine to increase adhesion. Cortical cells (taken from the entire cortex) were obtained from newborn Wistar rats. The dissociated cells were plated at a concentration of 106 cells/ml, and allowed to adhere for 2 hours. Then the non-adhering cells were removed by refreshing the medium which was changed twice a week. The resulting monolayer had an initial density of about 5000 cells/mm2, gradually decreasing to ~2500 cells/mm2 after 2 weeks The total plated area is about 100 mm2, so with 250000 cells, at last. The MEA's electrode area of approximately 2.5 mm2 comprises about 12500 to 6250 cells. The cultures were stored in an incubator at 37°C, 5% CO2 and near 100% humidity. Custom made LabView (National Instruments, Austin, Tx) programs were used to control data acquisition.
### Results
#### Neuronal morphology and network topology
Both field-guided growing networks (Figure 1 A, B, C) and randomly growing networks (Figure S1) generated quite complex neurite topologies for our large scale networks of 10,000–50,000 neurons. In the guided models, axons grow towards locations with relatively high somatic density. We observed that axons tended to grow “in parallel”, which became more recognizable in longer simulations. Figure 1A shows the neurite structures of 0.5% (randomly chosen) of the neurons (note some bundles of axonal trunks in close up, fig. 1B). While neurite trees grew with the course of time, axons encountered dendrites of other neurons and generated local connections. Figure 1C shows the neurite structure of a typical pyramidal neuron (black), its axon (black) and dendrites (red) and the somas of its postsynaptic neurons (red) after 21 vDIV. Figures 1D, E, F show parallel growth features in experimental cultures from three different labs, older than the1st week in vitro.
While the number of synapses per neuron, referred to as connectivity, increased (Fig. 2A, blue dashed line), the neurons connected to more neurons, at longer metric distances. This resulted in shortening of the characteristic path length (L) (Fig. 2A, red and green curves, each averaged over 5 network realizations), and less unreachable neurons.
Voigt et al. [10] showed that cultured cortical networks may contain about 5% fast-growing neurons (large GABA-ergic neurons) which play an excitatory role in early developmental stages. To mimic those neurons, we doubled the neurite elongation rate in 5% of the randomly chosen neurons and inverted the negative weights of their synapses. Their longer neurites created connection shortcuts between neurons at relatively large metric distance, which further increased the percentage of reachable neurons and decreased the characteristic path length L (see eq. 3; Fig. 2A, green curve), compared to networks without such neurons at corresponding age (Fig. 2A, red curve). Larger networks had higher values of L, as shown in the inset of Figure 2 A
Figure 2B shows developmental curves (each averaged over 5 network realizations) of the clustering coefficient (C) and “small-world-ness” (S), see equations (2) and (4). In all models C slowly increased with time. Figure 2B shows 2 typical examples of the development of C (dashed lines) and S (solid lines) in field-guided networks with (red) and without large GABA-ergic neurons (green). Randomly growing networks showed very similar values of L, C and S (not shown here). Compared with other neurons, large GABA-ergic neurons had more extensive neurite arborizations, so they were superior in interconnecting nearby neurons. A relatively higher C as the result of more interconnected neighborhoods also suggests that large GABA-ergic neurons may facilitate effective generation of a small-world topology.
When <k> ~1, the estimated average path length Lrand converges to ∞. Therefore, S shows relatively high values shortly after the onset of network formation. When first connections were formed, S had high values (peak around 170 at vDIV 4). At this early stage of topology development networks usually had small sets of chain-linked neurons with L = 10 (without large GABA-ergic neurons) or L = 30 (with large GABA-ergic neurons). After its peak, S decreased exponentially with time as shown in Figure 2 B. As S was always higher than 1, all generated topologies were classified as small-world according to definition in [29]. As expected, S was always higher in networks with large GABA-ergic neurons than without. Larger networks had higher values of C and S as shown in inset of Figure 2B.
#### Development of bursting activity
We examined four different models: randomly growing and field-guided network models, both with and without large GABA-ergic neurons. For each type we generated up to 3 different realizations of growing networks. In this paragraph we show results from one of the network realizations for each model type. Other realizations showed similar development of intra- and inter- burst parameters. Different realizations of the networks had slightly different numbers of the various neuronal types, but that did not influence the final outcome. Spiking activity was simulated for 1 hour per virtual day for 3 virtual weeks. At every vDIV we applied a burst detection algorithm on spike sequences, acquired at 100 differently mapped virtual micro-electrode array (MEA) layouts (each with 60 electrodes, see methods). The starting point of bursting activity was identified whenever the algorithm detected the first burst. As soon as bursting started, of the maximum firing rate mFr could be calculated. In field-guided networks, the presence of large GABA-ergic neurons resulted in a 3 vDIVs earlier onset of bursting (green: vDIV 10 vs. blue: vDIV 13), whereas it did not affect the first day of bursting in randomly growing networks (magenta and red: vDIV 12). Figure 3 shows the average development of mFr during bursts in the 4 model types (dashed lines), as well as an experimentally determined average (solid line) of 5 cortical networks presented in [18]. Figure 3 shows a common trend in experimental data of increasing mFr during the 2nd and at the beginning of the 3rd week and decreasing or stabilizing mFr thereafter. A similar trend was only observed in networks with large GABA-ergic neurons (green and magenta).
At later stages of development (2nd half of 3rd virtual week) in the models with large GABA-ergic neurons, bursting activity was dominated by superbursts giving the network relatively shorter time (less than 100 ms) to recover (i.e. elevation of the neuronal membrane potential from reset to resting membrane potential). Therefore during superbursts networks could recruit fewer neurons which resulted in stabilizing mFr during the subsequent bursts.
For every vDIV we calculated inter burst intervals (IBIs). Both in experimental and simulated data IBIs had characteristic skewed distributions. Figures 4A and B show typical examples based on 1 h samples at 18 DIV from recorded data (4A) and simulated data with a field-guided network with large GABA-ergic neurons (4B). Figure 4C shows IBI median curves acquired from 5 cultures (solid lines) and 4 simulations of different network types (dashed lines). The majority of experiments and simulations share a common tendency of shortening IBIs over time.
#### Spatial activity propagation (burst waves) and boundary reverberation
In this section we describe the spatiotemporal spiking patterns generated by the network models. In all simulations we observed a wave-like propagation with “reverberating” activity (along the circular network borders) as shown in Figure 5.
We noticed that bursts started spontaneously at random places or local areas and then slowly recruited neighboring regions. This relatively slow recruitment appeared as pre-burst phases in network burst shapes (spike rate versus time). Upon sufficient recruitment the bursts quickly propagated as waves through the whole network leaving behind a pool of “depressed neurons” which were characterized by a membrane potential value below the resting potential. During bursts, spiking activity was usually higher at the network borders, creating a notable reverberating wave along the network boundary. With given speed of the propagating wave and neuronal recovery, in larger networks, where the traveling wave has to cross a longer distance, the pool of depressed neurons should have more time to recover before the wave fades out. We tested this assumption in one realization of a network model with 50,000 neurons. Simulations of larger networks indeed showed numerous local after-waves raising and fading for brief periods (of 10 ms). The pool of recovered neurons in larger networks frequently showed activity after the main wave. Local after-waves left a print on burst profiles as low-firing post-burst phases. Pre- and post-burst phases were highly variable, as also observed in experimental data [16]. In contrast, smaller networks (of 10,000 neurons) very rarely generated post-burst phases, or highly variable pre-burst phases. Only 2 out of 6 smaller networks showed post-burst phases at the end of the 3rd virtual week (around 19 vDIV) whereas larger networks showed similar results 7 vDIVs earlier. Figure 6 shows typical examples of burst profiles from network models with 10,000 neurons at 12 and 19 vDIVs (A and B respectively), and 50,000 neurons at 12 vDIV (C), as well as an example of experimental bursts at 19 DIV (D) taken from a previous study [16].
We also found that networks with large GABA-ergic neurons could produce series of bursts with IBIs shorter than 1 s, referred to as superbursts. These networks showed firing between the bursts in chain-like series of events, providing more time (and additional synaptic input) for neuronal recovery. When feedbacks along the network border were activated, these networks produced the next burst shortly after the previous one (1 sec or less). Figure 7 shows a raster plot of a super burst generated by a field-guided network of 50,000 cells with large GABA-ergic neurons. To verify that feedback along the border around the network facilitates super-bursts, we ran several simulations without an outgrowth restricting circular border, i.e. nothing confined neurite outgrowth beyond the network area. Such networks did not generate IBIs ≤1 s, while the intra- and inter- burst parameters were similar to those in networks with border restricted outgrowth as described above. However, the shortest IBIs were about 2 sec.
### Discussion
We employed large scale networks of 10,000–50,000 neurons to analyze bursting activity generated by two sequentially combined models. In the first model growing neurons formed a self-wired topology which yielded network parameters that were entered into the second model to generate spiking activity. This approach can be used for studying network behavior at different levels ranging from spiking activity patterns of individual neurons or local circuits to more global assemblies showing synchronous bursting. In the present study we focused on network bursting as perceived experimentally by mapping the 60-electrodes MEA layout onto the network space. To our knowledge, such a combination of models has never been reported before. In a recent study by Tetzlaff et al. neuronal avalanche development was simulated with an alternative network model where neurites are represented as probability zones and connectivity is derived from the overlap of these zones [34]. Their model demonstrates the interplay between activity and connectivity which our model is not capable of. However, the topology of the network is not produced by Tetzlaff's model; for that, a more detailed description of the neurite outgrowth would be necessary.
The automatic adjustment of various mutually interdependent network parameters is one of the major advantages of our current approach. In fact, connectivity, axonal delays and synaptic strengths are linked together by the neurite maps of individual neurons. The connectivity parameter (number of synapses per neuron) depends on the spatial distance between axons and dendrites of pre- and post-synaptic neurons, respectively. Delays and synaptic strengths depend on axonal length and the distance from the synapse to the soma, respectively. These relationships exist only in networks where connectivity is an emergent property of neuronal morphology. Therefore, given realistic parameters for generating neurite maps, a network presumably acquires a more realistic connective topology. This differs completely from commonly employed methods such as random wiring of synaptic connections [16], [26], [27]. Moreover, the growth model introduces the “dynamic” developmental time dimension into network modeling, allowing also comparison to development of activity during long-term culturing. As stated above (see Methods, development of network morphology) we used a 1–day time step in the growth development. As an extra check, this 1-day step was compared against smaller steps of 6 and 12 hours; these steps gave the same results as the 1-day step.
#### Morphology and activity development
During axonal outgrowth neurons connected to an exponentially increasing number of other neurons. This led to an increased connection probability between two random neurons, and resulted on average in a lower number of intermediate neurons between two not directly connected neurons, thus decreasing the average graph distance. Furthermore, at each subsequent vDIV network graphs acquired more interconnected neighborhoods as indicated by an increased C. All created topological structures were characterized as small-world graphs, and S showed values comparable to other network examples (e.g. in neural network of C.elegans S = 4.51) [29]. The small-world-ness (S) scales up with increasing network size as indicated by Humphries and Gurney [29] and confirmed by our simulations (Fig. 2B inset). Following the definition of Humphries and Gurney, the topology of networks with connectivity equivalent to mature cultures (3 weeks and older) is close to random as S approaches 1. In the first virtual week, groups of nearby neurons formed local circuits of around 10 to 30 neurons. By the middle of the second week these growing circuits started to connect, allowing the whole network to synchronize.
Analysis of (synchronized) network activity was performed using intra- and inter-burst parameters. On average, network bursts grew in size (mFr) and burst rates increased, thus reducing IBIs. Wagenaar et al. [5] showed similar trends in the majority of cultured networks. In their experiments the median of array-wide spike rate and bursting index increased during the first 3 weeks of culture development. In all models network synchronization mFr tended to rise at later stages (10–13th vDIV) than in cultured networks (usually 7–10th DIV), e.g. [5], [35], [36]. However, Wagenaar et al. showed that smaller cultures usually develop bursting activity at later stages than larger cultures [17]. In this work we did not attempt to analyze spiking activity between the bursts as it largely varies at different levels (e.g. from neuron to neuron, culture to culture) and would require much more experiments.
By increasing the elongation rate in a subset of neurons, thereby generating extensive neuritic structures like in large GABA-ergic cells, young networks also gained shorter graph distances. With such a set of fast growing neurons, network models produced a lower path length L and a higher clustering coefficient C, resulting in a more effective small-world structure (higher S). Effectively, these neurons acted as small hubs as supported by the results of a recent experimental study by Bonifazi et al. [37]. These reduced distances promoted the development of bursts only in field-guided networks. This effect may be explained in the following way. At early developmental stages of simulated networks, neurons have relatively small and sparse neurite arborizations. This reduces the probability of any growing axon to encounter other neurons unless axons are guided in their direction. Therefore, in randomly growing models, the presence of large GABA-ergic neurons has little effect on network connectivity and, thus, bursting started around the same virtual day as in models without large GABA-ergic structures. However, in field-guided models the axons of large GABA-ergic neurons did facilitate connection of local circuits, promoting earlier network burst development. A calcium imaging study by Voigt et al. [10] showed that chemically manipulated cultured networks without large GABA-ergic neurons usually did not develop synchronous activity, which supports the hypothesis that the GABA system promotes the early development of synchronized firing in cultured networks. It is generally assumed that GABA-ergic neurons maintain their excitatory function only during the first two weeks, and then develop into inhibitory neurons. This change of role was not incorporated in our models (large GABA-ergic neurons kept their positive synaptic weights during 3 virtual weeks), which might lead to discrepancies between simulated and experimental data. However, other in vitro studies suggested that the GABA-ergic system may also have an excitatory role even in mature neural networks and may regulate neurite outgrowth (e.g. for review see [], [9], [38,39]). This implies that differences in the development of firing patterns might also be caused by GABA-mediated outgrowth [10]. However, our models did not cover the mechanisms behind neurite outgrowth in chemically manipulated cultured networks. Rather, we used fixed parameters found in studies on normally developing cortical cells [12] and assigned positive weights to their synapses as suggested by Robertson and Menne [38]. Our results showed that even without GABA-mediated outgrowth, large GABA-ergic neurons have a significant effect on the development of firing patterns in field-guided networks. Compared to the other models these networks generated several properties closely resembling experimental data, i.e. earlier start of bursting, moderate increase of mFr and similar development of IBIs.
The essential role of GABA-ergic neurons in synchronization of neuronal activity in cortical cultures was described by Voigt et al. (2001). Our simulation results support their findings and shed light on the excitatory role of large GABA-ergic neurons in the developmental process of cultured cortical networks. Maybe this is as well applicable to in vivo networks. In particular, our results suggest that large GABA-ergic neurons may play a crucial role in triggering early cortical activity (and thus enhance prenatal brain development).
We concluded that simulated networks with large GABA-ergic neurons and axonal guidance showed better agreement to cultured networks than the other models. Therefore we further focused on these models. It is however important to note that the IBI range can also depend on the (mean Poissonian) rate of synaptic noise. In particular, increasing this rate results in reduction of the IBI range (Gritsun et al. 2011). In this study we used constant mean rates of synaptic noise in all the simulations.
Bundles of neurites growing in parallel were formed in the field-guided networks, as seen in experimental networks. The bundles resulted from axons growing along common paths towards spots with higher somatic density. Randomly growing simulation models showed no bundles; neurites grew independently. In contrast, Zubler and Douglas [14] presented a model where neurite bundles were formed due to mechanical processes that modulated neuronal migration. In their study, bundle formation was influenced directly by increasing the attraction strength between growing neurites, whereas our study assumes an alternative (indirect) mechanism based on chemotactic guidance.
For clarity, it is important to note that our approach was based on the assumption of a rather stationary position of grown neurites which, in experimental reality, requires efficiently strong neuronal adhesion to the surface. Insufficient adhesion to the surface usually leads to clustering in experimental preparations. The above described weak bundling should not be confused with the aggregation that occurs when adhesion degrades and the networks subdivides into well defined clusters “islands”, connected by massive thick axonal bundles [40], [41], [42]. Understanding of bundling mechanisms may also be very helpful in the design of central and peripheral highly selective neural prostheses [43], [44].
#### Spatio-temporal propagation of network bursts
Even though the majority of the bursts had their own unique distribution of spiking activity, in all network simulations we observed wave-like propagating patterns with several phases. First, a set of easily excitable neurons with strong interconnections in a local area was activated in a chain-like reaction. Their firing increased background activity to connected neurons, thus facilitating activation of those neurons. This prepared the network for the next phase (see Fig. 7, at about 50 ms after the first activity), the fast propagating main-wave of the network burst. This main wave left behind a large pool of depressed neurons which could not be activated shortly after the burst, which usually led to burst cessation, as shown in a previous study [16]. Part of the neurons in that pool, those with relatively fast recovery, occasionally participated in the following “after-wave” spike chains. These spatio-temporal phases reflected on burst shapes as pre-, main- and post phases, as illustrated in Video S1. After-waves usually occurred near the border of the circular network as a result of stronger local connectivity in this area. Since the neurites of frontier neurons could not grow beyond the space of the network, they were “forced” to grow further along the circular boundary. This resulted in a relatively high neurite density and therefore a higher synaptic density in the network border region. This yielded a relatively high synaptic input to the frontier neurons, giving networks a major feedback pathway along their border. When the “after-wave” phase lasted long enough for the other neurons to recover, a subsequent burst could be generated shortly afterwards, with similar phases. This may explain the mechanism behind the generation of superbursts as in experiments, e.g. [5]. This view is supported by the observation that networks without outgrowth restricted boundary did not generate superbursts.
#### Boundary conditions and population size
We analyzed the activity of networks with different population sizes. For all network sizes the higher neurite density at the borders provided stronger connectivity and more possible feedback pathways than in the middle of the network. In larger network propagating burst waves had more freedom to travel through the pools of recovered neurons, particularly in these feedback pathways. This may explain the observations that larger network generated highly variable bursting patterns which incorporated both pre- and post-burst phases whereas small networks of 10,000 neurons showed less variable pre-phases only. The development of a prolonged after-wave phase reached its maximum at earlier developmental stages in larger networks. This effect was characterized by earlier occurrence of bursts as well as super bursts in larger network than in small ones, similar to experimental observations by Wagenaar et al. [5].
It is important to note that developing activity patterns can be influenced by several other factors such as long-term synaptic plasticity [45] and apoptosis, incorporation of which may further improve our simulation model. We have shown that up to three weeks LTP does not yet need to be incorporated to explain burt properties in detail. At later times, it will probably have to. The model described here is a good basis for further explorations in those directions.
### Supporting Information
Appendix S1.
S1-1. Growth model parameters. S1-2a. Activity model parameters. S1-2b. Synapse model and parameters.
doi:10.1371/journal.pone.0043352.s001
(DOCX)
Figure S1.
Simulation of neurite morphology in a randomly growing network of 10,000 neurons. The neuronal somas are indicated in green. For 0.5% of these neurons the neurite structures are shown: axons (black) and dendrites (red). The close-up shows only the somas (marked with green and red dots) and axons sprouting from the red marked neurons.
doi:10.1371/journal.pone.0043352.s002
(TIF)
Video S1.
Visualization of spiking activity in a large network of 50,000 neurons with morphological structure at 12 virtual DIV. Example of a burst series generated by the field-guided model with large GABA-ergic neurons. Top left: Demonstration of the spatio-temporal propagation of spiking waves. The dots show the spatial location of the firing neurons. The circle illustrates the network boundary. Bottom: Shape of the network bursts, as acquired by the virtual MEA (60 electrodes).
doi:10.1371/journal.pone.0043352.s003
(AVI)
### Acknowledgments
We thank Dr. Jan Stegenga for sharing the experimental data and prof. Stefan Luding for sharing computational resources with us.
### Author Contributions
Conceived and designed the experiments: TAG JF WLCR. Performed the experiments: TAG. Analyzed the data: TAG. Contributed reagents/materials/analysis tools: TAG JF WLCR. Wrote the paper: TAG JF WLCR.
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https://tel.archives-ouvertes.fr/tel-00719791 | # Gamma ray astronomy and the origin of galactic cosmic rays
1 APC - AHE - APC - Astrophysique des Hautes Energies
APC - UMR 7164 - AstroParticule et Cosmologie, Dipartimemto di Astronomia, Universita degli Studi di Bologna
Abstract : Diffusive shock acceleration operating at expanding supernova remnant shells is by far the most popular model for the origin of galactic cosmic rays. Despite the general consensus received by the model, an unambiguous and conclusive proof of the supernova remnant hypothesis is still missing. In this context, the recent developments in gamma ray astronomy provide us with precious insights into the problem of the origin of galactic cosmic rays, since production of gamma rays is expected both during the acceleration of cosmic rays at supernova remnant shocks and during their subsequent propagation in the interstellar medium. In particular, the recent detection of a number of supernova remnants at TeV energies nicely fits with the model, but it still does not constitute a conclusive proof of it, mainly due to the difficulty of disentangling the hadronic and leptonic contributions to the observed gamma ray emission. The main goal of my research is to search for an unambiguous and conclusive observational test for proving (or disproving) the idea that supernova remnants are the sources of galactic cosmic rays with energies up to (at least) the cosmic ray knee. Our present comprehension of the mechanisms of particle acceleration at shocks and of the propagation of cosmic rays in turbulent magnetic fields encourages beliefs that such a conclusive test might come from future observations of supernova remnants and of the Galaxy in the almost unexplored domain of multi-TeV gamma rays.
Keywords :
Type de document :
HDR
High Energy Astrophysical Phenomena [astro-ph.HE]. Université Paris-Diderot - Paris VII, 2011
Domaine :
https://tel.archives-ouvertes.fr/tel-00719791
Contributeur : Stefano Gabici <>
Soumis le : vendredi 20 juillet 2012 - 21:10:37
Dernière modification le : mardi 11 octobre 2016 - 13:25:39
Document(s) archivé(s) le : dimanche 21 octobre 2012 - 03:31:10
### Identifiants
• HAL Id : tel-00719791, version 1
### Citation
Stefano Gabici. Gamma ray astronomy and the origin of galactic cosmic rays. High Energy Astrophysical Phenomena [astro-ph.HE]. Université Paris-Diderot - Paris VII, 2011. <tel-00719791>
Consultations de
la notice
## 336
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https://www.science.gov/topicpages/p/pour+plate+method.html | #### Sample records for pour plate method
1. Machine for Automatic Bacteriological Pour Plate Preparation
PubMed Central
Sharpe, A. N.; Biggs, D. R.; Oliver, R. J.
1972-01-01
A fully automatic system for preparing poured plates for bacteriological analyses has been constructed and tested. The machine can make decimal dilutions of bacterial suspensions, dispense measured amounts into petri dishes, add molten agar, mix the dish contents, and label the dishes with sample and dilution numbers at the rate of 2,000 dishes per 8-hr day. In addition, the machine can be programmed to select different media so that plates for different types of bacteriological analysis may be made automatically from the same sample. The machine uses only the components of the media and sterile polystyrene petri dishes; requirements for all other materials, such as sterile pipettes and capped bottles of diluents and agar, are eliminated. Images PMID:4560475
2. Aseptic laboratory techniques: plating methods.
PubMed
Sanders, Erin R
2012-05-11
Microorganisms are present on all inanimate surfaces creating ubiquitous sources of possible contamination in the laboratory. Experimental success relies on the ability of a scientist to sterilize work surfaces and equipment as well as prevent contact of sterile instruments and solutions with non-sterile surfaces. Here we present the steps for several plating methods routinely used in the laboratory to isolate, propagate, or enumerate microorganisms such as bacteria and phage. All five methods incorporate aseptic technique, or procedures that maintain the sterility of experimental materials. Procedures described include (1) streak-plating bacterial cultures to isolate single colonies, (2) pour-plating and (3) spread-plating to enumerate viable bacterial colonies, (4) soft agar overlays to isolate phage and enumerate plaques, and (5) replica-plating to transfer cells from one plate to another in an identical spatial pattern. These procedures can be performed at the laboratory bench, provided they involve non-pathogenic strains of microorganisms (Biosafety Level 1, BSL-1). If working with BSL-2 organisms, then these manipulations must take place in a biosafety cabinet. Consult the most current edition of the Biosafety in Microbiological and Biomedical Laboratories (BMBL) as well as Material Safety Data Sheets (MSDS) for Infectious Substances to determine the biohazard classification as well as the safety precautions and containment facilities required for the microorganism in question. Bacterial strains and phage stocks can be obtained from research investigators, companies, and collections maintained by particular organizations such as the American Type Culture Collection (ATCC). It is recommended that non-pathogenic strains be used when learning the various plating methods. By following the procedures described in this protocol, students should be able to: Perform plating procedures without contaminating media. Isolate single bacterial colonies by the streak-plating
3. Aseptic Laboratory Techniques: Plating Methods
PubMed Central
Sanders, Erin R.
2012-01-01
Microorganisms are present on all inanimate surfaces creating ubiquitous sources of possible contamination in the laboratory. Experimental success relies on the ability of a scientist to sterilize work surfaces and equipment as well as prevent contact of sterile instruments and solutions with non-sterile surfaces. Here we present the steps for several plating methods routinely used in the laboratory to isolate, propagate, or enumerate microorganisms such as bacteria and phage. All five methods incorporate aseptic technique, or procedures that maintain the sterility of experimental materials. Procedures described include (1) streak-plating bacterial cultures to isolate single colonies, (2) pour-plating and (3) spread-plating to enumerate viable bacterial colonies, (4) soft agar overlays to isolate phage and enumerate plaques, and (5) replica-plating to transfer cells from one plate to another in an identical spatial pattern. These procedures can be performed at the laboratory bench, provided they involve non-pathogenic strains of microorganisms (Biosafety Level 1, BSL-1). If working with BSL-2 organisms, then these manipulations must take place in a biosafety cabinet. Consult the most current edition of the Biosafety in Microbiological and Biomedical Laboratories (BMBL) as well as Material Safety Data Sheets (MSDS) for Infectious Substances to determine the biohazard classification as well as the safety precautions and containment facilities required for the microorganism in question. Bacterial strains and phage stocks can be obtained from research investigators, companies, and collections maintained by particular organizations such as the American Type Culture Collection (ATCC). It is recommended that non-pathogenic strains be used when learning the various plating methods. By following the procedures described in this protocol, students should be able to: ● Perform plating procedures without contaminating media. ● Isolate single bacterial colonies by the
4. Plating methods, a survey
NASA Technical Reports Server (NTRS)
Berkowitz, J. B.; Emerson, N. H.
1972-01-01
Results are presented of a comprehensive search of the literature available, much of which has been generated by the research centers of NASA and its contractors, on plating and coating methods and techniques. Methods covered included: (1) electroplating from aqueous solutions; (2) electroplating from nonaqueous solutions; (3) electroplating from fused-salt baths; (4) electroforming; (5) electroless plating, immersion plating, and mirroring; (6) electroplating from gaseous plasmas; and (7) anodized films and conversion coatings.
5. Spiral Salmonella assay: validation against the standard pour-plate assay.
PubMed
Diehl, M; Fort, F
1996-01-01
The spiral Ames assay, an automated approach to bacterial mutagenicity testing which simplifies the test procedure and reduces the amount of drug required to generate mutagenic dose-response information, has been evaluated and validated for routine screening. The spiral plater delivers the Salmonella bacteria, exogenous metabolic activation system and drug to the surface of a rotating agar plate one on top of another in such a way that a uniform density of bacteria is exposed to a logarithmically decreasing volume of drug. Following an incubation of 48 hr at 37 degrees C, the plates are scanned by a laser counter, and the data are subjected to a computerized analysis. Petri plates of 15 cm diameter were used to provide a concentration range of about 250-fold per plate. The Salmonella were concentrated 20-fold to increase sensitivity. Thirty-eight compounds from a variety of chemical classes, including both pharmaceuticals and known mutagens of moderate to strong potency, were tested in both the spiral and the standard pour-plate assays. There was overall test agreement on positive or negative results for 82% of the compounds tested. When only the results from strains TA98 plus TA100 were considered, the agreement was 87%. When positive results were obtained, the fold increase over vehicle control was on average twice as great for the spiral assay compared to the pour-plate assay. It was concluded that the two assay procedures generally provided comparable results, with the spiral assay being somewhat more sensitive in terms of dose-response than the pour-plate assay.
6. Aluminum transfer method for plating plastics
NASA Technical Reports Server (NTRS)
Goodrich, W. D.; Stalmach, C. J., Jr.
1977-01-01
Electroless plating technique produces plate of uniform thickness. Hardness and abrasion resistance can be increased further by heat treatment. Method results in seamless coating over many materials, has low thermal conductivity, and is relatively inexpensive compared to conventional methods.
7. Consecutive Plate Acoustic Suppressor Apparatus and Methods
NASA Technical Reports Server (NTRS)
Doychak, Joseph (Inventor); Parrott, Tony L. (Inventor)
1993-01-01
An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.
8. METHOD OF MAKING AND PLATE CONNECTION
DOEpatents
Patriarca, P.; Shubert, C.E.; Slaughter, G.M.
1963-02-26
This invention relates to a method of joining, by welding or brazing, a tube to a plate, particularly where the tube and the plate are of different thickness or have different thermal conductivities and are subject to high temperatures. In this method the tube is inserted in the core of a plate containing an annular groove in its back face concentric with the bore and in communication with the bore. One end of the tube is welded substantially flush with the front end of the plate. Brazing alloy is placed in the groove on the back face of the plate and heat is applied to the plate and tube to melt the brazing alloy to permit the alloy to flow into the bore and bond the tube to the plate. (AEC)
9. Method for plating with metal oxides
DOEpatents
Silver, G.L.; Martin, F.S.
1994-08-23
A method is disclosed of plating hydrous metal oxides on at least one substrate, which method is indifferent to the electrochemical properties of the substrate, and comprises reacting metallic ions in aqueous solution with an appropriate oxidizing agent such as sodium hypochlorite or calcium sulfite with oxygen under suitable conditions of pH and concentration such that oxidation and precipitation of metal oxide are sufficiently slow to allow satisfactory plating of metal oxide on the substrate. 1 fig.
10. Method for plating with metal oxides
DOEpatents
Silver, Gary L.; Martin, Frank S.
1994-08-23
A method of plating hydrous metal oxides on at least one substrate, which method is indifferent to the electrochemical properties of the substrate, and comprises reacting metallic ions in aqueous solution with an appropriate oxidizing agent such as sodium hypochlorite or calcium sulfite with oxygen under suitable conditions of pH and concentration such that oxidation and precipitation of metal oxide are sufficiently slow to allow satisfactory plating of metal oxide on the substrate.
11. Effusion plate using additive manufacturing methods
DOEpatents
Johnson, Thomas Edward; Keener, Christopher Paul; Ostebee, Heath Michael; Wegerif, Daniel Gerritt
2016-04-12
Additive manufacturing techniques may be utilized to construct effusion plates. Such additive manufacturing techniques may include defining a configuration for an effusion plate having one or more internal cooling channels. The manufacturing techniques may further include depositing a powder into a chamber, applying an energy source to the deposited powder, and consolidating the powder into a cross-sectional shape corresponding to the defined configuration. Such methods may be implemented to construct an effusion plate having one or more channels with a curved cross-sectional geometry.
12. Method of manufacturing battery plate groups
SciTech Connect
Marui, T.; Uwani, T.
A method is described of manufacturing battery plate groups which comprises (a) providing a pliable, smooth, continuous glass fiber mat which has a predetermined thickness, (b) providing a pair of plastic rotors which are aligned in parallel, the rotors including circumferential surfaces and equal numbers of projections extending outwardly from their circumferential surfaces a distance of between 0.7 mm and 2mm, (c) spacing the rotors apart such that a clearance is provided between the projections on one rotor and the circumferential surface of the other rotor which is between 1/3 and 1/2 the predetermined thickness of the glass fiber mat,more » (d) rotating both the rotors such that the projections from one rotor are displaced by half a pitch from the projections from the other rotor, (e) passing the glass fiber mat between the rotors such that the projections thereon form alternately-directed folding habits therein at regular intervals along its length and to provide interconnected separator portions which are aligned in an accordion-like fashion, (f) providing an alternating series of positive and negative battery plates on only one side of the interconnected separator portions, and (g) sequentially inserting the positive and negative battery plates between adjacent separator portions.« less
13. Apparatus and method for controlling plating uniformity
DOEpatents
Hachman Jr., John T.; Kelly, James J.; West, Alan C.
2004-10-12
The use of an insulating shield for improving the current distribution in an electrochemical plating bath is disclosed. Numerical analysis is used to evaluate the influence of shield shape and position on plating uniformity. Simulation results are compared to experimental data for nickel deposition from a nickel--sulfamate bath. The shield is shown to improve the average current density at a plating surface.
14. Accuracy of Multiple Pour Cast from Various Elastomer Impression Methods
PubMed Central
Saad Toman, Majed; Ali Al-Shahrani, Abdullah; Ali Al-Qarni, Abdullah
2016-01-01
The accurate duplicate cast obtained from a single impression reduces the profession clinical time, patient inconvenience, and extra material cost. The stainless steel working cast model assembly consisting of two abutments and one pontic area was fabricated. Two sets of six each custom aluminum trays were fabricated, with five mm spacer and two mm spacer. The impression methods evaluated during the study were additional silicone putty reline (two steps), heavy-light body (one step), monophase (one step), and polyether (one step). Type IV gypsum casts were poured at the interval of one hour, 12 hours, 24 hours, and 48 hours. The resultant cast was measured with traveling microscope for the comparative dimensional accuracy. The data obtained were subjected to Analysis of Variance test at significance level <0.05. The die obtained from two-step putty reline impression techniques had the percentage of variation for the height −0.36 to −0.97%, while diameter was increased by 0.40–0.90%. The values for one-step heavy-light body impression dies, additional silicone monophase impressions, and polyether were −0.73 to −1.21%, −1.34%, and −1.46% for the height and 0.50–0.80%, 1.20%, and −1.30% for the width, respectively. PMID:28096815
15. Application of the variational-asymptotical method to composite plates
NASA Technical Reports Server (NTRS)
Hodges, Dewey H.; Lee, Bok W.; Atilgan, Ali R.
1992-01-01
A method is developed for the 3D analysis of laminated plate deformation which is an extension of a variational-asymptotical method by Atilgan and Hodges (1991). Both methods are based on the treatment of plate deformation by splitting the 3D analysis into linear through-the-thickness analysis and 2D plate analysis. Whereas the first technique tackles transverse shear deformation in the second asymptotical approximation, the present method simplifies its treatment and restricts it to the first approximation. Both analytical techniques are applied to the linear cylindrical bending problem, and the strain and stress distributions are derived and compared with those of the exact solution. The present theory provides more accurate results than those of the classical laminated-plate theory for the transverse displacement of 2-, 3-, and 4-layer cross-ply laminated plates. The method can give reliable estimates of the in-plane strain and displacement distributions.
16. A computed microtomography method for understanding epiphyseal growth plate fusion
Staines, Katherine A.; Madi, Kamel; Javaheri, Behzad; Lee, Peter D.; Pitsillides, Andrew A.
2017-12-01
The epiphyseal growth plate is a developmental region responsible for linear bone growth, in which chondrocytes undertake a tightly regulated series of biological processes. Concomitant with the cessation of growth and sexual maturation, the human growth plate undergoes progressive narrowing, and ultimately disappears. Despite the crucial role of this growth plate fusion ‘bridging’ event, the precise mechanisms by which it is governed are complex and yet to be established. Progress is likely hindered by the current methods for growth plate visualisation; these are invasive and largely rely on histological procedures. Here we describe our non-invasive method utilising synchrotron x-ray computed microtomography for the examination of growth plate bridging, which ultimately leads to its closure coincident with termination of further longitudinal bone growth. We then apply this method to a dataset obtained from a benchtop microcomputed tomography scanner to highlight its potential for wide usage. Furthermore, we conduct finite element modelling at the micron-scale to reveal the effects of growth plate bridging on local tissue mechanics. Employment of these 3D analyses of growth plate bone bridging is likely to advance our understanding of the physiological mechanisms that control growth plate fusion.
17. Investigation on filter method for smoothing spiral phase plate
Zhang, Yuanhang; Wen, Shenglin; Luo, Zijian; Tang, Caixue; Yan, Hao; Yang, Chunlin; Liu, Mincai; Zhang, Qinghua; Wang, Jian
2018-03-01
Spiral phase plate (SPP) for generating vortex hollow beams has high efficiency in various applications. However, it is difficult to obtain an ideal spiral phase plate because of its continuous-varying helical phase and discontinued phase step. This paper describes the demonstration of continuous spiral phase plate using filter methods. The numerical simulations indicate that different filter method including spatial domain filter, frequency domain filter has unique impact on surface topography of SPP and optical vortex characteristics. The experimental results reveal that the spatial Gaussian filter method for smoothing SPP is suitable for Computer Controlled Optical Surfacing (CCOS) technique and obtains good optical properties.
18. Novel fabrication method of microchannel plates
Yi, Whikun; Jeong, Taewon; Jin, Sunghwan; Yu, SeGi; Lee, Jeonghee; Kim, J. M.
2000-11-01
We have developed a novel microchannel plate (MCP) by introducing new materials and process technologies. The key features of our MCP are summarized as follows: (i) bulk alumina as a substrate, (ii) the channel location defined by a programmed-hole puncher, (iii) thin film deposition by electroless plating and/or sol-gel process, and (iv) an easy fabrication process suitable for mass production and a large-sized MCP. The characteristics of the resulting MCP have been evaluated with a high input current source such as a continuous electron beam from an electron gun and Spindt-type field emitters to obtain information on electron multiplication. In the case of a 0.28 μA incident beam, the output current enhances ˜170 times, which is equal to 1% of the total bias current of the MCP at a given bias voltage of 2600 V. When we insert a MCP between the cathode and the anode of a field emission display panel, the brightness of luminescent light increases 3-4 times by multiplying the emitted electrons through pore arrays of a MCP.
19. Conductivity fuel cell collector plate and method of fabrication
DOEpatents
Braun, James C.
2002-01-01
An improved method of manufacturing a PEM fuel cell collector plate is disclosed. During molding a highly conductive polymer composite is formed having a relatively high polymer concentration along its external surfaces. After molding the polymer rich layer is removed from the land areas by machining, grinding or similar process. This layer removal results in increased overall conductivity of the molded collector plate. The polymer rich surface remains in the collector plate channels, providing increased mechanical strength and other benefits to the channels. The improved method also permits greater mold cavity thickness providing a number of advantages during the molding process.
20. A method for making an alkaline battery electrode plate
NASA Technical Reports Server (NTRS)
Chida, K.; Ezaki, T.
1983-01-01
A method is described for making an alkaline battery electrode plate where the desired active substances are filled into a nickel foam substrate. In this substrate an electrolytic oxidation reduction occurs in an alkaline solution containing lithium hydroxide.
1. Clinical comparison of two different plating methods in minimally invasive plate osteosynthesis for clavicular midshaft fractures: A randomized controlled trial.
PubMed
Sohn, Hoon-Sang; Shon, Min Soo; Lee, Kyung-Hag; Song, Si-Jung
2015-11-01
The aim of this study was to compare the clinical and radiographic outcomes between two different plating methods (superior vs. anteroinferior) in minimally invasive plate osteosynthesis (MIPO) for acute displaced clavicular shaft fractures. A prospective, randomized controlled trial was performed in a single centre. Nineteen patients were treated with superior plating and 18 with anteroinferior plating using the MIPO technique. A 3.5-mm locking reconstruction plate was bent preoperatively and applied to either the anteroinferior or superior aspect of the clavicle through two separate incisions. The operating time, time to union, the proportional length difference, complications, and functional outcome of the shoulder joint were evaluated using the Constant score and the University of California Los Angeles (UCLA) score. There was no statistically significant difference in the Constant score and UCLA score. The mean time to union was 16.8 weeks for superior plating and 17.1 weeks for anteroinferior plating (p=0.866). The average operation time was 77.2min in superior plating and 79.4min in anteroinferior plating (p=0.491). One patient in the superior plating group showed plate failure. Despite no significant difference, one patient had nonunion in the superior plating group (p>0.999). From a clinical perspective, although MIPO with anteroinferior plating provides better outcomes especially in complications without statistically significant difference, both plating methods provided satisfactory clinical and radiographic outcomes. Level I, a single-centre, prospective, randomized controlled trial. Copyright © 2015 Elsevier Ltd. All rights reserved.
2. Method to reduce damage to backing plate
DOEpatents
Perry, Michael D.; Banks, Paul S.; Stuart, Brent C.
2001-01-01
The present invention is a method for penetrating a workpiece using an ultra-short pulse laser beam without causing damage to subsequent surfaces facing the laser. Several embodiments are shown which place holes in fuel injectors without damaging the back surface of the sack in which the fuel is ejected. In one embodiment, pulses from an ultra short pulse laser remove about 10 nm to 1000 nm of material per pulse. In one embodiment, a plasma source is attached to the fuel injector and initiated by common methods such as microwave energy. In another embodiment of the invention, the sack void is filled with a solid. In one other embodiment, a high viscosity liquid is placed within the sack. In general, high-viscosity liquids preferably used in this invention should have a high damage threshold and have a diffusing property.
3. Method for conducting electroless metal-plating processes
DOEpatents
Petit, George S.; Wright, Ralph R.
1978-01-01
This invention is an improved method for conducting electroless metal-plating processes in a metal tank which is exposed to the plating bath. The invention solves a problem commonly encountered in such processes: how to determine when it is advisable to shutdown the process in order to clean and/or re-passivate the tank. The new method comprises contacting the bath with a current-conducting, non-catalytic probe and, during plating operations, monitoring the gradually changing difference in electropotential between the probe and tank. It has been found that the value of this voltage is indicative of the extent to which nickel-bearing decomposition products accumulate on the tank. By utilizing the voltage to determine when shutdown for cleaning is advisable, the operator can avoid premature shutdown and at the same time avoid prolonging operations to the point that spontaneous decomposition occurs.
4. Inverse methods-based estimation of plate coupling in a plate motion model governed by mantle flow
Ratnaswamy, V.; Stadler, G.; Gurnis, M.
2013-12-01
Plate motion is primarily controlled by buoyancy (slab pull) which occurs at convergent plate margins where oceanic plates undergo deformation near the seismogenic zone. Yielding within subducting plates, lateral variations in viscosity, and the strength of seismic coupling between plate margins likely have an important control on plate motion. Here, we wish to infer the inter-plate coupling for different subduction zones, and develop a method for inferring it as a PDE-constrained optimization problem, where the cost functional is the misfit in plate velocities and is constrained by the nonlinear Stokes equation. The inverse models have well resolved slabs, plates, and plate margins in addition to a power law rheology with yielding in the upper mantle. Additionally, a Newton method is used to solve the nonlinear Stokes equation with viscosity bounds. We infer plate boundary strength using an inexact Gauss-Newton method with line search for backtracking. Each inverse model is applied to two simple 2-D scenarios (each with three subduction zones), one with back-arc spreading and one without. For each case we examine the sensitivity of the inversion to the amount of surface velocity used: 1) full surface velocity data and 2) surface velocity data simplified using a single scalar average (2-D equivalent to an Euler pole) for each plate. We can recover plate boundary strength in each case, even in the presence of highly nonlinear flow with extreme variations in viscosity. Additionally, we ascribe an uncertainty in each plate's velocity and perform an uncertainty quantification (UQ) through the Hessian of the misfit in plate velocities. We find that as plate boundaries become strongly coupled, the uncertainty in the inferred plate boundary strength decreases. For very weak, uncoupled subduction zones, the uncertainty of inferred plate margin strength increases since there is little sensitivity between plate margin strength and plate velocity. This result is significant
5. A generalized plate method for estimating total aerobic microbial count.
PubMed
Ho, Kai Fai
2004-01-01
The plate method outlined in Chapter 61: Microbial Limit Tests of the U.S. Pharmacopeia (USP 61) provides very specific guidance for assessing total aerobic bioburden in pharmaceutical articles. This methodology, while comprehensive, lacks the flexibility to be useful in all situations. By studying the plate method as a special case within a more general family of assays, the effects of each parameter in the guidance can be understood. Using a mathematical model to describe the plate counting procedure, a statistical framework for making more definitive statements about total aerobic bioburden is developed. Such a framework allows the laboratory scientist to adjust the USP 61 methods to satisfy specific practical constraints. In particular, it is shown that the plate method can be conducted, albeit with stricter acceptance criteria, using a test specimen quantity that is smaller than the 10 g or 10 mL prescribed in the guidance. Finally, the interpretation of results proffered by the guidance is re-examined within this statistical framework and shown to be overly aggressive.
6. Methods of localization of Lamb wave sources on thin plates
Turkaya, Semih; Toussaint, Renaud; Kvalheim Eriksen, Fredrik; Daniel, Guillaume; Grude Flekkøy, Eirik; Jørgen Måløy, Knut
2015-04-01
Signal localization techniques are ubiquitous in both industry and academic communities. We propose a new localization method on plates which is based on energy amplitude attenuation and inverted source amplitude comparison. This inversion is tested on synthetic data using Lamb wave propagation direct model and on experimental dataset (recorded with 4 Brüel & Kjær Type 4374 miniature piezoelectric shock accelerometers (1-26 kHz frequency range)). We compare the performance of the technique to the classical source localization algorithms, arrival time localization, time reversal localization, localization based on energy amplitude. Furthermore, we measure and compare the accuracy of these techniques as function of sampling rate, dynamic range, geometry, Signal to Noise Ratio, and we show that this very versatile technique works better than classical ones over the sampling rates 100kHz - 1MHz. Experimental phase consists of a glass plate having dimensions of 80cmx40cm with a thickness of 1cm. Generated signals due to a wooden hammer hit or a steel ball hit are captured by sensors placed on the plate on different locations with the mentioned sensors. Numerical simulations are done using dispersive far field approximation of plate waves. Signals are generated using a hertzian loading over the plate. Using imaginary sources outside the plate boundaries the effect of reflections is also included. This proposed method, can be modified to be implemented on 3d environments, monitor industrial activities (e.g boreholes drilling/production activities) or natural brittle systems (e.g earthquakes, volcanoes, avalanches).
7. Theoretical and Experimental Methods in Hypersonic Flows (Les Methodes Theoriques et Experimentales pour l’Etude Des Ecoulements Hypersoniques)
DTIC Science & Technology
1993-04-01
PROCEEDINGS 514 OELECTE f Theoretical and A U Experimental Methods in A Hypersonic Flows (Les Methodes Th6oriques et Experimentales pour 1’Etude des...nitrogen ent for both equilibrium and non -equilibrium chemistry between the two groups . Both groups state that the boundary makes this mode even more...flowfield on control is also m?,ndatory unstable due to the necessary oblate shape of Hermes. when the experimental rebuilding is clearly poor and
8. Microchannel plate detector and methods for their fabrication
SciTech Connect
Elam, Jeffrey W.; Mane, Anil U.; Peng, Qing
A multi-component tunable resistive coating and methods of depositing the coating on the surfaces of a microchannel plate (MCP) detector. The resistive coating composed of a plurality of alternating layers of a metal oxide resistive component layer and a conductive component layer composed of at least one of a metal, a metal nitride and a metal sulfide. The coating may further include an emissive layer configured to produce a secondary electron emission in response to a particle interacting with the MCP and a neutron-absorbing layer configured to respond to a neutron interacting with the MCP.
9. Enumeration of total aerobic microorganisms in foods by SimPlate Total Plate Count-Color Indicator methods and conventional culture methods: collaborative study.
PubMed
Feldsine, Philip T; Leung, Stephanie C; Lienau, Andrew H; Mui, Linda A; Townsend, David E
2003-01-01
The relative efficacy of the SimPlate Total Plate Count-Color Indicator (TPC-CI) method (SimPlate 35 degrees C) was compared with the AOAC Official Method 966.23 (AOAC 35 degrees C) for enumeration of total aerobic microorganisms in foods. The SimPlate TPC-CI method, incubated at 30 degrees C (SimPlate 30 degrees C), was also compared with the International Organization for Standardization (ISO) 4833 method (ISO 30 degrees C). Six food types were analyzed: ground black pepper, flour, nut meats, frozen hamburger patties, frozen fruits, and fresh vegetables. All foods tested were naturally contaminated. Nineteen laboratories throughout North America and Europe participated in the study. Three method comparisons were conducted. In general, there was <0.3 mean log count difference in recovery among the SimPlate methods and their corresponding reference methods. Mean log counts between the 2 reference methods were also very similar. Repeatability (Sr) and reproducibility (SR) standard deviations were similar among the 3 method comparisons. The SimPlate method (35 degrees C) and the AOAC method were comparable for enumerating total aerobic microorganisms in foods. Similarly, the SimPlate method (30 degrees C) was comparable to the ISO method when samples were prepared and incubated according to the ISO method.
10. Method for Reduction of Silver Biocide Plating on Metal Surfaces
NASA Technical Reports Server (NTRS)
Steele, John; Nalette, Timothy; Beringer, Durwood
2013-01-01
Silver ions in aqueous solutions (0.05 to 1 ppm) are used for microbial control in water systems. The silver ions remain in solution when stored in plastic containers, but the concentration rapidly decreases to non-biocidal levels when stored in metal containers. The silver deposits onto the surface and is reduced to non-biocidal silver metal when it contacts less noble metal surfaces, including stainless steel, titanium, and nickel-based alloys. Five methods of treatment of contact metal surfaces to deter silver deposition and reduction are proposed: (1) High-temperature oxidation of the metal surface; (2) High-concentration silver solution pre-treatment; (3) Silver plating; (4) Teflon coat by vapor deposition (titanium only); and (5) A combination of methods (1) and (2), which proved to be the best method for the nickel-based alloy application. The mechanism associated with surface treatments (1), (2), and (5) is thought to be the development of a less active oxide layer that deters ionic silver deposition. Mechanism (3) is an attempt to develop an equilibrium ionic silver concentration via dissolution of metallic silver. Mechanism (4) provides a non-reactive barrier to deter ionic silver plating. Development testing has shown that ionic silver in aqueous solution was maintained at essentially the same level of addition (0.4 ppm) for up to 15 months with method (5) (a combination of methods (1) and (2)), before the test was discontinued for nickel-based alloys. Method (1) resulted in the maintenance of a biocidal level (approximately 0.05 ppm) for up to 10 months before that test was discontinued for nickel-based alloys. Methods (1) and (2) used separately were able to maintain ionic silver in aqueous solution at essentially the same level of addition (0.4 ppm) for up to 10 months before the test was discontinued for stainless steel alloys. Method (3) was only utilized for titanium alloys, and was successful at maintaining ionic silver in aqueous solution at
11. Models of convection-driven tectonic plates - A comparison of methods and results
NASA Technical Reports Server (NTRS)
King, Scott D.; Gable, Carl W.; Weinstein, Stuart A.
1992-01-01
Recent numerical studies of convection in the earth's mantle have included various features of plate tectonics. This paper describes three methods of modeling plates: through material properties, through force balance, and through a thin power-law sheet approximation. The results obtained are compared using each method on a series of simple calculations. From these results, scaling relations between the different parameterizations are developed. While each method produces different degrees of deformation within the surface plate, the surface heat flux and average plate velocity agree to within a few percent. The main results are not dependent upon the plate modeling method and herefore are representative of the physical system modeled.
12. A Study on the Saving Method of Plate Jigs in Hull Block Butt Welding
Ko, Dae-Eun
2017-11-01
A large amount of plate jigs is used for alignment of welding line and control of welding deformations in hull block assembly stage. Besides material cost, the huge working man-hours required for working process of plate jigs is one of the obstacles in productivity growth of shipyard. In this study, analysis method was proposed to simulate the welding deformations of block butt joint with plate jigs setting. Using the proposed analysis method, an example simulation was performed for actual panel block joint to investigate the saving method of plate jigs. Results show that it is possible to achieve two objectives of quality accuracy of the hull block and saving the plate jig usage at the same time by deploying the plate jigs at the right places. And the proposed analysis method can be used in establishing guidelines for the proper use of plate jigs in block assembly stage.
13. Perforated plates for cryogenic regenerators and method of fabrication
DOEpatents
Hendricks, J.B.
1994-03-29
Perforated plates having very small holes with a uniform diameter throughout the plate thickness are prepared by a [open quotes]wire drawing[close quotes] process in which a billet of sacrificial metal is disposed in an extrusion can of the plate metal, and the can is extruded and restacked repeatedly, converting the billet to a wire of the desired hole diameter. At final size, the rod is then sliced into wafers, and the wires are removed by selective etching. This process is useful for plate metals of interest for high performance regenerator applications, in particular, copper, niobium, molybdenum, erbium, and other rare earth metals. Er[sub 3]Ni, which has uniquely favorable thermophysical properties for such applications, may be incorporated in regions of the plates by providing extrusion cans containing erbium and nickel metals in a stacked array with extrusion cans of the plate metal, which may be copper. The array is heated to convert the erbium and nickel metals to Er[sub 3]Ni. Perforated plates having two sizes of perforations, one of which is small enough for storage of helium, are also disclosed. 10 figures.
14. Perforated plates for cryogenic regenerators and method of fabrication
DOEpatents
Hendricks, John B.
1994-01-01
Perforated plates (10) having very small holes (14) with a uniform diameter throughout the plate thickness are prepared by a "wire drawing" process in which a billet of sacrificial metal is disposed in an extrusion can of the plate metal, and the can is extruded and restacked repeatedly, converting the billet to a wire of the desired hole diameter. At final size, the rod is then sliced into wafers, and the wires are removed by selective etching. This process is useful for plate metals of interest for high performance regenerator applications, in particular, copper, niobium, molybdenum, erbium, and other rare earth metals. Er.sub.3 Ni, which has uniquely favorable thermophysical properties for such applications, may be incorporated in regions of the plates by providing extrusion cans (20) containing erbium and nickel metals in a stacked array (53) with extrusion cans of the plate metal, which may be copper. The array is heated to convert the erbium and nickel metals to Er.sub.3 Ni. Perforated plates having two sizes of perforations (38, 42), one of which is small enough for storage of helium, are also disclosed.
15. Method for regeneration of electroless nickel plating solution
DOEpatents
Eisenmann, Erhard T.
1997-01-01
An electroless nickel(EN)/hypophosphite plating bath is provided employing acetic acid/acetate as a buffer and which is, as a result, capable of perpetual regeneration while avoiding the production of hazardous waste. A regeneration process is provided to process the spent EN plating bath solution. A concentrated starter and replenishment solution is provided for ease of operation of the plating bath. The regeneration process employs a chelating ion exchange system to remove nickel cations from spent EN plating solution. Phosphites are then removed from the solution by precipitation. The nickel cations are removed from the ion exchange system by elution with hypophosphorous acid and the nickel concentration of the eluate adjusted by addition of nickel salt. The treated solution and adjusted eluate are combined, stabilizer added, and the volume of resulting solution reduced by evaporation to form the bath starter and replenishing solution.
16. Method for regeneration of electroless nickel plating solution
DOEpatents
Eisenmann, E.T.
1997-03-11
An electroless nickel(EN)/hypophosphite plating bath is provided employing acetic acid/acetate as a buffer and which is, as a result, capable of perpetual regeneration while avoiding the production of hazardous waste. A regeneration process is provided to process the spent EN plating bath solution. A concentrated starter and replenishment solution is provided for ease of operation of the plating bath. The regeneration process employs a chelating ion exchange system to remove nickel cations from spent EN plating solution. Phosphites are then removed from the solution by precipitation. The nickel cations are removed from the ion exchange system by elution with hypophosphorus acid and the nickel concentration of the eluate adjusted by addition of nickel salt. The treated solution and adjusted eluate are combined, stabilizer added, and the volume of resulting solution reduced by evaporation to form the bath starter and replenishing solution. 1 fig.
17. A Modified Kirchhoff plate theory for Free Vibration analysis of functionally graded material plates using meshfree method
Nguyen Van Do, Vuong
2018-04-01
In this paper, a modified Kirchhoff theory is presented for free vibration analyses of functionally graded material (FGM) plate based on modified radial point interpolation method (RPIM). The shear deformation effects are taken account into modified theory to ignore the locking phenomenon of thin plates. Due to the proposed refined plate theory, the number of independent unknowns reduces one variable and exists with four degrees of freedom per node. The simulated free vibration results employed by the modified RPIM are compared with the other analytical solutions to verify the effectiveness and the accuracy of the developed mesh-free method. Detail parametric studies of the proposed method are then conducted including the effectiveness of thickness ratio, boundary condition and material inhomogeneity on the sample problems of square plates. Results illustrated that the modified mesh-free RPIM can effectively predict the numerical calculation as compared to the exact solutions. The obtained numerical results are indicated that the proposed method are stable and well accurate prediction to evaluate with other published analyses.
18. Detection of License Plate using Sliding Window, Histogram of Oriented Gradient, and Support Vector Machines Method
Astawa, INGA; Gusti Ngurah Bagus Caturbawa, I.; Made Sajayasa, I.; Dwi Suta Atmaja, I. Made Ari
2018-01-01
The license plate recognition usually used as part of system such as parking system. License plate detection considered as the most important step in the license plate recognition system. We propose methods that can be used to detect the vehicle plate on mobile phone. In this paper, we used Sliding Window, Histogram of Oriented Gradient (HOG), and Support Vector Machines (SVM) method to license plate detection so it will increase the detection level even though the image is not in a good quality. The image proceed by Sliding Window method in order to find plate position. Feature extraction in every window movement had been done by HOG and SVM method. Good result had shown in this research, which is 96% of accuracy.
19. Special Course on Inverse Methods for Airfoil Design for Aeronautical and Turbomachinery Applications (Methodes Inverses pour la Conception des Profils Porteurs pour des Applications dans les Domaines de l’Aeronautique et des Turbomachines)
DTIC Science & Technology
1990-11-01
engined jet aircraft wing MID PLA CROSS tCTO% taking into account the effects of the propulsive system. -DESIGN PAAMETERS DESTIGE PARAMETERS 5CT 0 (MC 0...AGARD Report No.780 Special Course on Inverse Methods for Airfoil Design for Aeronautical and Turbomachinery Applications (M6thodes Inverses pour la...manufacturing systems. Blade or airfoil designs are normally made in two steps, and the lectures are accordingly grouped into two parts. - - In the
20. Method and apparatus for enhancing microchannel plate data
DOEpatents
Thoe, Robert S.
1987-01-01
A method and apparatus for determining centroid channel locations is disclosed for use in a system activated by one or more multichannel plates (16,18) and including a linear diode array (24) providing channels of information 1, 2, . . . , n, . . . , N containing signal amplitudes A.sub.n. A source of analog A.sub.n signals (40), and a source of digital clock signals n (48), are provided. Non-zero A.sub.n values are detected in a discriminator (42). A digital signal representing p, the value of n immediately preceding that whereat A.sub.n takes its first non-zero value, is generated in a scaler (50). The analog A.sub.n signals are converted to digital in an analog to digital converter (44). The digital A.sub.n signals are added to produce a digital .SIGMA.A.sub.n signal in a full adder (46). Digital 1, 2, . . . , m signals representing the number of non-zero A.sub.n are produced by a discriminator pulse counter (52). Digital signals representing 1 A.sub.p+ 1, 2 A.sub.p+2, . . . , m A.sub.p+m are produced by pairwise multiplication in multiplier (54). These signals are added in multiplier summer (56) to produce a digital .SIGMA.nA.sub.n -p.SIGMA.A.sub.n signal. This signal is divided by the digital .SIGMA.A.sub.n signal in divider (58) to provide a digital (.SIGMA.nA.sub.n /.SIGMA.A.sub.n) -p signal. Finally, this last signal is added to the digital p signal in an offset summer (60) to provide .SIGMA.nA.sub.n /.SIGMA.A.sub.n, the centroid channel locations.
1. Method and apparatus for enhancing microchannel plate data
DOEpatents
Thoe, R.S.
1983-10-24
A method and apparatus for determining centroid channel locations are disclosed for use in a system activated by one or more multichannel plates and including a linear diode array providing channels of information 1, 2, ...,n, ..., N containing signal amplitudes A/sub n/. A source of analog A/sub n/ signals, and a source of digital clock signals n, are provided. Non-zero A/sub n/ values are detected in a discriminator. A digital signal representing p, the value of n immediately preceding that whereat A/sub n/ takes its first non-zero value, is generated in a scaler. The analog A/sub n/ signals are converted to digital in an analog to digital converter. The digital A/sub n/ signals are added to produce a digital ..sigma..A/sub n/ signal in a full adder. Digital 1, 2, ..., m signals representing the number of non-zero A/sub n/ are produced by a discriminator pulse counter. Digital signals representing 1 A/sub p+1/, 2 A/sub p+2/, ..., m A/sub p+m/ are produced by pairwise multiplication in multiplier. These signal are added in multiplier summer to produce a digital ..sigma..nA/sub n/ - p..sigma..A/sub n/ signal. This signal is divided by the digital ..sigma..A/sub n/ signal in divider to provide a digital (..sigma..nA/sub n//..sigma..A/sub n/) -p signal. Finally, this last signal is added to the digital p signal in an offset summer to provide ..sigma..nA/sub n//..sigma..A/sub n/, the centroid channel locations.
2. Methods for measuring plating thicknesses on TAB lead frames
NASA Technical Reports Server (NTRS)
Hagen, M. P.
1977-01-01
Plating three layer tape lead frames, used for tape automated bonding, offers a challenge to the electroplater because of nonuniform topography. Each lead frame contains large (typically .05 x. .05 inch) flat test pads located around the perimeter of the frame. These test pads are electrically connected to the bondable lead frame fingers which extend into an area in the center of the frame called the feature hole. The feature hole exposes these fingers to plating on all sides, while the test pads are exposed on only one side. In addition, the fingers are small in cross section (typically .003 x .0015 inches). Recent thickness measurements indicate that plating around the lead frame fingers is nearly twice as thick as that on test pad areas. Procedures and equipment were developed for measuring the thickness of the deposited material. Discussion was centered on the data obtained using the various measurement techniques and equipment.
3. Systems and methods for forming microchannel plate (MCP) photodetector assemblies
SciTech Connect
Xia, Lei; Zhao, Huyue; Wagner, Robert G.
A MCP photodetector assembly includes an anode plate including a plurality of electrical traces positioned thereon, a plurality of MCPs and a plurality of grid spacers. The MCPs are positioned between the grid spacers. The grid spacers have a grid spacer shape defining at least one aperture. A plurality of shims are positioned between the grid spacers and the MCPs so as to form a stack positioned on the anode plate. Each of the plurality of shims have a shim shape which is the same as the grid spacer shape such that each of the plurality of shims and eachmore » of the plurality of grid spacers overlap so as to define at least one MCP aperture. At least a portion of the plurality of MCPs are positioned within the MCP aperture. The shims are structured to electrically couple the MCPs to the anode plate.« less
4. Fuel cell collector plate and method of fabrication
DOEpatents
Braun, James C.; Zabriskie, Jr., John E.; Neutzler, Jay K.; Fuchs, Michel; Gustafson, Robert C.
2001-01-01
An improved molding composition is provided for compression molding or injection molding a current collector plate for a polymer electrolyte membrane fuel cell. The molding composition is comprised of a polymer resin combined with a low surface area, highly-conductive carbon and/or graphite powder filler. The low viscosity of the thermoplastic resin combined with the reduced filler particle surface area provide a moldable composition which can be fabricated into a current collector plate having improved current collecting capacity vis-a-vis comparable fluoropolymer molding compositions.
5. Computed radiography imaging plates and associated methods of manufacture
DOEpatents
Henry, Nathaniel F.; Moses, Alex K.
2015-08-18
Computed radiography imaging plates incorporating an intensifying material that is coupled to or intermixed with the phosphor layer, allowing electrons and/or low energy x-rays to impart their energy on the phosphor layer, while decreasing internal scattering and increasing resolution. The radiation needed to perform radiography can also be reduced as a result.
6. Chinese License Plates Recognition Method Based on A Robust and Efficient Feature Extraction and BPNN Algorithm
Zhang, Ming; Xie, Fei; Zhao, Jing; Sun, Rui; Zhang, Lei; Zhang, Yue
2018-04-01
The prosperity of license plate recognition technology has made great contribution to the development of Intelligent Transport System (ITS). In this paper, a robust and efficient license plate recognition method is proposed which is based on a combined feature extraction model and BPNN (Back Propagation Neural Network) algorithm. Firstly, the candidate region of the license plate detection and segmentation method is developed. Secondly, a new feature extraction model is designed considering three sets of features combination. Thirdly, the license plates classification and recognition method using the combined feature model and BPNN algorithm is presented. Finally, the experimental results indicate that the license plate segmentation and recognition both can be achieved effectively by the proposed algorithm. Compared with three traditional methods, the recognition accuracy of the proposed method has increased to 95.7% and the consuming time has decreased to 51.4ms.
7. Method of obtaining intensified image from developed photographic films and plates
NASA Technical Reports Server (NTRS)
1978-01-01
A method is explained of obtaining intensified images from silver images on developed photographic films and plates. The steps involve converting silver of the developed film or plate to a radioactive compound by treatment with an aqueous alkaline solution of an organo-S35 compound; placing the treated film or plate in direct contact with a receiver film which is then exposed by radiation from the activated film; and developing and fixing the resulting intensified image on the receiver film.
8. Methode d'identification parametrique pour la surveillance in situ des joints a recouvrement par propagation d'ondes vibratoires
Francoeur, Dany
Cette these de doctorat s'inscrit dans le cadre de projets CRIAQ (Consortium de recherche et d'innovation en aerospatiale du Quebec) orientes vers le developpement d'approches embarquees pour la detection de defauts dans des structures aeronautiques. L'originalite de cette these repose sur le developpement et la validation d'une nouvelle methode de detection, quantification et localisation d'une entaille dans une structure de joint a recouvrement par la propagation d'ondes vibratoires. La premiere partie expose l'etat des connaissances sur l'identification d'un defaut dans le contexte du Structural Health Monitoring (SHM), ainsi que la modelisation de joint a recouvrements. Le chapitre 3 developpe le modele de propagation d'onde d'un joint a recouvrement endommage par une entaille pour une onde de flexion dans la plage des moyennes frequences (10-50 kHz). A cette fin, un modele de transmission de ligne (TLM) est realise pour representer un joint unidimensionnel (1D). Ce modele 1D est ensuite adapte a un joint bi-dimensionnel (2D) en faisant l'hypothese d'un front d'onde plan incident et perpendiculaire au joint. Une methode d'identification parametrique est ensuite developpee pour permettre a la fois la calibration du modele du joint a recouvrement sain, la detection puis la caracterisation de l'entaille situee sur le joint. Cette methode est couplee a un algorithme qui permet une recherche exhaustive de tout l'espace parametrique. Cette technique permet d'extraire une zone d'incertitude reliee aux parametres du modele optimal. Une etude de sensibilite est egalement realisee sur l'identification. Plusieurs resultats de mesure sur des joints a recouvrements 1D et 2D sont realisees permettant ainsi l'etude de la repetabilite des resultats et la variabilite de differents cas d'endommagement. Les resultats de cette etude demontrent d'abord que la methode de detection proposee est tres efficace et permet de suivre la progression d'endommagement. De tres bons resultats
9. Particle response to shock waves in solids: dynamic witness plate/PIV method for detonations
Murphy, Michael J.; Adrian, Ronald J.
2007-08-01
Studies using transparent, polymeric witness plates consisting of polydimethlysiloxane (PDMS) have been conducted to measure the output of exploding bridge wire (EBW) detonators and exploding foil initiators (EFI). Polymeric witness plates are utilized to alleviate particle response issues that arise in gaseous flow fields containing shock waves and to allow measurements of shock-induced material velocities to be made using particle image velocimetry (PIV). Quantitative comparisons of velocity profiles across the shock waves in air and in PDMS demonstrate the improved response achieved by the dynamic witness plate method. Schlieren photographs complement the analysis through direct visualization of detonator-induced shock waves in the witness plates.
10. The constraint method: A new finite element technique. [applied to static and dynamic loads on plates
NASA Technical Reports Server (NTRS)
Tsai, C.; Szabo, B. A.
1973-01-01
An approch to the finite element method which utilizes families of conforming finite elements based on complete polynomials is presented. Finite element approximations based on this method converge with respect to progressively reduced element sizes as well as with respect to progressively increasing orders of approximation. Numerical results of static and dynamic applications of plates are presented to demonstrate the efficiency of the method. Comparisons are made with plate elements in NASTRAN and the high-precision plate element developed by Cowper and his co-workers. Some considerations are given to implementation of the constraint method into general purpose computer programs such as NASTRAN.
11. Characterisation of structure-borne sound source using reception plate method.
PubMed
Putra, A; Saari, N F; Bakri, H; Ramlan, R; Dan, R M
2013-01-01
A laboratory-based experiment procedure of reception plate method for structure-borne sound source characterisation is reported in this paper. The method uses the assumption that the input power from the source installed on the plate is equal to the power dissipated by the plate. In this experiment, rectangular plates having high and low mobility relative to that of the source were used as the reception plates and a small electric fan motor was acting as the structure-borne source. The data representing the source characteristics, namely, the free velocity and the source mobility, were obtained and compared with those from direct measurement. Assumptions and constraints employing this method are discussed.
12. The complex variable reproducing kernel particle method for bending problems of thin plates on elastic foundations
Chen, L.; Cheng, Y. M.
2018-07-01
In this paper, the complex variable reproducing kernel particle method (CVRKPM) for solving the bending problems of isotropic thin plates on elastic foundations is presented. In CVRKPM, one-dimensional basis function is used to obtain the shape function of a two-dimensional problem. CVRKPM is used to form the approximation function of the deflection of the thin plates resting on elastic foundation, the Galerkin weak form of thin plates on elastic foundation is employed to obtain the discretized system equations, the penalty method is used to apply the essential boundary conditions, and Winkler and Pasternak foundation models are used to consider the interface pressure between the plate and the foundation. Then the corresponding formulae of CVRKPM for thin plates on elastic foundations are presented in detail. Several numerical examples are given to discuss the efficiency and accuracy of CVRKPM in this paper, and the corresponding advantages of the present method are shown.
13. Chemical plating method of preparing radiation source material
DOEpatents
Smith, P.K.; Huntoon, R.T.; Mosley, W.C. Jr.
1973-12-11
A uniform dispersion of a radioisotope within a noble metal matrix is provided by chemically plating a noble metal coating onto particles including a dissociable compound of the mdioisotope. A suspension of the dissociable compound in a chemically reductive solution is prepared and noble metal cations added to produce the noble metal coatings. The coated particles are filtered, dried and heated to calcine the dissociable compound to a refractory powder. The powder can be encapsulated in measured portions or consolidated and shaped into an elongated form for easy apportionnnent as radiation source material. (Official Gazette)
14. A comparison between orthogonal and parallel plating methods for distal humerus fractures: a prospective randomized trial.
PubMed
Lee, Sang Ki; Kim, Kap Jung; Park, Kyung Hoon; Choy, Won Sik
2014-10-01
With the continuing improvements in implants for distal humerus fractures, it is expected that newer types of plates, which are anatomically precontoured, thinner and less irritating to soft tissue, would have comparable outcomes when used in a clinical study. The purpose of this study was to compare the clinical and radiographic outcomes in patients with distal humerus fractures who were treated with orthogonal and parallel plating methods using precontoured distal humerus plates. Sixty-seven patients with a mean age of 55.4 years (range 22-90 years) were included in this prospective study. The subjects were randomly assigned to receive 1 of 2 treatments: orthogonal or parallel plating. The following results were assessed: operating time, time to fracture union, presence of a step or gap at the articular margin, varus-valgus angulation, functional recovery, and complications. No intergroup differences were observed based on radiological and clinical results between the groups. In our practice, no significant differences were found between the orthogonal and parallel plating methods in terms of clinical outcomes, mean operation time, union time, or complication rates. There were no cases of fracture nonunion in either group; heterotrophic ossification was found 3 patients in orthogonal plating group and 2 patients in parallel plating group. In our practice, no significant differences were found between the orthogonal and parallel plating methods in terms of clinical outcomes or complication rates. However, orthogonal plating method may be preferred in cases of coronal shear fractures, where posterior to anterior fixation may provide additional stability to the intraarticular fractures. Additionally, parallel plating method may be the preferred technique used for fractures that occur at the most distal end of the humerus.
15. A novel method for characterizing the impact response of functionally graded plates
Larson, Reid A.
Functionally graded material (FGM) plates are advanced composites with properties that vary continuously through the thickness of the plate. Metal-ceramic FGM plates have been proposed for use in thermal protection systems where a metal-rich interior surface of the plate gradually transitions to a ceramic-rich exterior surface of the plate. The ability of FGMs to resist impact loads must be demonstrated before using them in high-temperature environments in service. This dissertation presents a novel technique by which the impact response of FGM plates is characterized for low-velocity, low- to medium-energy impact loads. An experiment was designed where strain histories in FGM plates were collected during impact events. These strain histories were used to validate a finite element simulation of the test. A parameter estimation technique was developed to estimate local material properties in the anisotropic, non-homogenous FGM plates to optimize the finite element simulations. The optimized simulations captured the physics of the impact events. The method allows research & design engineers to make informed decisions necessary to implement FGM plates in aerospace platforms.
16. Zone plate method for electronic holographic display using resolution redistribution technique.
PubMed
Takaki, Yasuhiro; Nakamura, Junya
2011-07-18
The resolution redistribution (RR) technique can increase the horizontal viewing-zone angle and screen size of electronic holographic display. The present study developed a zone plate method that would reduce hologram calculation time for the RR technique. This method enables calculation of an image displayed on a spatial light modulator by performing additions of the zone plates, while the previous calculation method required performing the Fourier transform twice. The derivation and modeling of the zone plate are shown. In addition, the look-up table approach was introduced for further reduction in computation time. Experimental verification using a holographic display module based on the RR technique is presented.
17. Isolation method (direct plating or enrichment) does not affect antimicrobial susceptibility of Campylobacter from chicken carcasses
USDA-ARS?s Scientific Manuscript database
To determine if Campylobacter isolation method influenced antimicrobial susceptibility results, the minimum inhibitory concentrations (MIC) of nine antimicrobials were compared for 291 pairs of Campylobacter isolates recovered from chicken carcass rinse samples using direct plating and an enrichment...
18. Method and apparatus for actively controlling a micro-scale flexural plate wave device
DOEpatents
Dohner, Jeffrey L.
2001-01-01
An actively controlled flexural plate wave device provides a micro-scale pump. A method of actively controlling a flexural plate wave device produces traveling waves in the device by coordinating the interaction of a magnetic field with actively controlled currents. An actively-controlled flexural plate wave device can be placed in a fluid channel and adapted for use as a micro-scale fluid pump to cool or drive micro-scale systems, for example, micro-chips, micro-electrical-mechanical devices, micro-fluid circuits, or micro-scale chemical analysis devices.
19. Electrochemical Device Comprising Composite Bipolar Plate and Method of Using the Same
NASA Technical Reports Server (NTRS)
Mittelsteadt, Cortney K. (Inventor); Braff, William A. (Inventor)
2013-01-01
An electrochemical device and methods of using the same. In one embodiment, the electrochemical device may be used as a fuel cell and/or as an electrolyzer and includes a membrane electrode assembly (MEA), an anodic gas diffusion medium in contact with the anode of the MEA, a cathodic gas diffusion medium in contact with the cathode, a first bipolar plate in contact with the anodic gas diffusion medium, and a second bipolar plate in contact with the cathodic gas diffusion medium. Each of the bipolar plates includes an electrically-conductive, chemically-inert, non-porous, liquid-permeable, substantially gas-impermeable membrane in contact with its respective gas diffusion medium, as well as a fluid chamber and a non-porous an electrically-conductive plate.
20. Electrochemical Device Comprising Composite Bipolar Plate and Method of Using the Same
NASA Technical Reports Server (NTRS)
Mittelsteadt, Cortney K. (Inventor); Braff, William A. (Inventor)
2017-01-01
An electrochemical device and methods of using the same. In one embodiment, the electrochemical device may be used as a fuel cell and/or as an electrolyzer and includes a membrane electrode assembly (MEA), an anodic gas diffusion medium in contact with the anode of the MEA, a cathodic gas diffusion medium in contact with the cathode, a first bipolar plate in contact with the anodic gas diffusion medium, and a second bipolar plate in contact with the cathodic gas diffusion medium. Each of the bipolar plates includes an electrically-conductive, chemically-inert, non-porous, liquid-permeable, substantially gas-impermeable membrane in contact with its respective gas diffusion medium, as well as a fluid chamber and a non-porous an electrically-conductive plate.
1. An Agar-Based Method for Plating Marine Protozoan Parasites of the Genus Perkinsus
PubMed Central
Cold, Emma R.; Freyria, Nastasia J.; Martínez Martínez, Joaquín; Fernández Robledo, José A.
2016-01-01
The genus Perkinsus includes protozoan parasites of mollusks responsible for losses in the aquaculture industry and hampering the recovery of natural shellfish beds worldwide, and they are a key taxon for understanding intracellular parasitism adaptations. The ability to propagate the parasite in liquid media, in the absence of the host, has been crucial for improving understanding of its biology; however, alternative techniques to grow the parasite are needed to explore other basic aspects of the Perkinsus spp. biology. We optimized a DME: Ham’s F12–5% FBS- containing solid agar medium for plating Perkinsus marinus. This solid medium supported trophozoite propagation both by binary fission and schizogony. Colonies were visible to the naked eye 17 days after plating. We tested the suitability of this method for several applications, including the following: 1) Subcloning P. marinus isolates: single discrete P. marinus colonies were obtained from DME: Ham’s F12–5% FBS– 0.75% agar plates, which could be further propagated in liquid medium; 2) Subcloning engineered Perkinsus mediterraneus MOE[MOE]: GFP by streaking cultures on plates; 3) Chemical susceptibility: Infusing the DME: Ham’s F12–5% FBS– 0.75% agar plates with triclosan resulted in inhibition of the parasite propagation in a dose-dependent manner. Altogether, our plating method has the potential for becoming a key tool for investigating diverse aspects of Perkinsus spp. biology, developing new molecular tools, and for biotechnological applications. PMID:27149378
2. An Agar-Based Method for Plating Marine Protozoan Parasites of the Genus Perkinsus.
PubMed
Cold, Emma R; Freyria, Nastasia J; Martínez Martínez, Joaquín; Fernández Robledo, José A
2016-01-01
The genus Perkinsus includes protozoan parasites of mollusks responsible for losses in the aquaculture industry and hampering the recovery of natural shellfish beds worldwide, and they are a key taxon for understanding intracellular parasitism adaptations. The ability to propagate the parasite in liquid media, in the absence of the host, has been crucial for improving understanding of its biology; however, alternative techniques to grow the parasite are needed to explore other basic aspects of the Perkinsus spp. biology. We optimized a DME: Ham's F12-5% FBS- containing solid agar medium for plating Perkinsus marinus. This solid medium supported trophozoite propagation both by binary fission and schizogony. Colonies were visible to the naked eye 17 days after plating. We tested the suitability of this method for several applications, including the following: 1) Subcloning P. marinus isolates: single discrete P. marinus colonies were obtained from DME: Ham's F12-5% FBS- 0.75% agar plates, which could be further propagated in liquid medium; 2) Subcloning engineered Perkinsus mediterraneus MOE[MOE]: GFP by streaking cultures on plates; 3) Chemical susceptibility: Infusing the DME: Ham's F12-5% FBS- 0.75% agar plates with triclosan resulted in inhibition of the parasite propagation in a dose-dependent manner. Altogether, our plating method has the potential for becoming a key tool for investigating diverse aspects of Perkinsus spp. biology, developing new molecular tools, and for biotechnological applications.
3. Applications of a General Finite-Difference Method for Calculating Bending Deformations of Solid Plates
NASA Technical Reports Server (NTRS)
Walton, William C., Jr.
1960-01-01
This paper reports the findings of an investigation of a finite - difference method directly applicable to calculating static or simple harmonic flexures of solid plates and potentially useful in other problems of structural analysis. The method, which was proposed in doctoral thesis by John C. Houbolt, is based on linear theory and incorporates the principle of minimum potential energy. Full realization of its advantages requires use of high-speed computing equipment. After a review of Houbolt's method, results of some applications are presented and discussed. The applications consisted of calculations of the natural modes and frequencies of several uniform-thickness cantilever plates and, as a special case of interest, calculations of the modes and frequencies of the uniform free-free beam. Computed frequencies and nodal patterns for the first five or six modes of each plate are compared with existing experiments, and those for one plate are compared with another approximate theory. Beam computations are compared with exact theory. On the basis of the comparisons it is concluded that the method is accurate and general in predicting plate flexures, and additional applications are suggested. An appendix is devoted t o computing procedures which evolved in the progress of the applications and which facilitate use of the method in conjunction with high-speed computing equipment.
4. Practical method of diffusion-welding steel plate in air
NASA Technical Reports Server (NTRS)
Holko, K. H.; Moore, T. J.
1971-01-01
Method is ideal for critical service requirements where parent metal properties are equaled in notch toughness, stress rupture and other characteristics. Welding technique variations may be used on a variety of materials, such as carbon steels, alloy steels, stainless steels, ceramics, and reactive and refractory materials.
5. Various methods of determining the natural frequencies and damping of composite cantilever plates. 3. The Ritz method
Ekel'chik, V. S.; Ryabov, V. M.
1997-03-01
The Ritz method was used to determine the frequencies and forms of free vibrations of rectangular cantilever plates made of anisotropic laminated composites. Orthogonal Jacobi and Legendre polynomials were used as coordinate functions. The results of the calculations are in good agreement with the published experimental and calculated data of other authors for plates made of boron and carbon fiber reinforced plastics with different angles of reinforcement of unidirectional layers and different sequence of placing the layers, and also of isotropic plates. The dissipative characteristics in vibrations were determined on the basis of the concept of complex moduli. The solution of the frequency equation with complex coefficients yields a complex frequency; the loss factors are determined from the ratio of the imaginary component of the complex frequency to the real component. For plates of unidirectionally reinforced carbon fiber plastic with different relative length a detailed analysis of the influence of the angle of reinforcement on the interaction and frequency transformation and on the loss factor was carried out. The article shows that the loss factor of a plate depends substantially on the type of vibration mode: bending or torsional. It also examines the asymptotics of the loss factors of plates when their length is increased, and it notes that the binomial model of deformation leads to a noticeable error in the calculation of the loss factor of long plates when the angle of reinforcement lies in the range 20°<φ<70°.
6. Method of forming aperture plate for electron microscope
NASA Technical Reports Server (NTRS)
Heinemann, K. (Inventor)
1974-01-01
An electron microscope is described with an electron source a condenser lens having either a circular aperture for focusing a solid cone of electrons onto a specimen or an annular aperture for focusing a hollow cone of electrons onto the specimen. It also has objective lens with an annular objective aperture, for focusing electrons passing through the specimen onto an image plane. A method of making the annular objective aperture using electron imaging, electrolytic deposition and ion etching techniques is included.
7. Natural frequencies of thin rectangular plates clamped on contour using the Finite Element Method
(Barboni Haţiegan, L.; Haţiegan, C.; Gillich, G. R.; Hamat, C. O.; Vasile, O.; Stroia, M. D.
2018-01-01
This paper presents the determining of natural frequencies of plates without and with damages using the finite element method of SolidWorks program. The first thirty natural frequencies obtained for thin rectangular rectangular plates clamped on contour without and with central damages a for different dimensions. The relative variation of natural frequency was determined and the obtained results by the finite element method (FEM) respectively relative variation of natural frequency, were graphically represented according to their vibration natural modes. Finally, the obtained results were compared.
8. A variable-order laminated plate theory based on the variational-asymptotical method
NASA Technical Reports Server (NTRS)
Lee, Bok W.; Sutyrin, Vladislav G.; Hodges, Dewey H.
1993-01-01
The variational-asymptotical method is a mathematical technique by which the three-dimensional analysis of laminated plate deformation can be split into a linear, one-dimensional, through-the-thickness analysis and a nonlinear, two-dimensional, plate analysis. The elastic constants used in the plate analysis are obtained from the through-the-thickness analysis, along with approximate, closed-form three-dimensional distributions of displacement, strain, and stress. In this paper, a theory based on this technique is developed which is capable of approximating three-dimensional elasticity to any accuracy desired. The asymptotical method allows for the approximation of the through-the-thickness behavior in terms of the eigenfunctions of a certain Sturm-Liouville problem associated with the thickness coordinate. These eigenfunctions contain all the necessary information about the nonhomogeneities along the thickness coordinate of the plate and thus possess the appropriate discontinuities in the derivatives of displacement. The theory is presented in this paper along with numerical results for the eigenfunctions of various laminated plates.
9. Cold plate
DOEpatents
Marroquin, Christopher M.; O'Connell, Kevin M.; Schultz, Mark D.; Tian, Shurong
2018-02-13
A cold plate, an electronic assembly including a cold plate, and a method for forming a cold plate are provided. The cold plate includes an interface plate and an opposing plate that form a plenum. The cold plate includes a plurality of active areas arranged for alignment over respective heat generating portions of an electronic assembly, and non-active areas between the active areas. A cooling fluid flows through the plenum. The plenum, at the non-active areas, has a reduced width and/or reduced height relative to the plenum at the active areas. The reduced width and/or height of the plenum, and exterior dimensions of cold plate, at the non-active areas allow the non-active areas to flex to accommodate surface variations of the electronics assembly. The reduced width and/or height non-active areas can be specifically shaped to fit between physical features of the electronics assembly.
10. Development of quadrilateral spline thin plate elements using the B-net method
Chen, Juan; Li, Chong-Jun
2013-08-01
The quadrilateral discrete Kirchhoff thin plate bending element DKQ is based on the isoparametric element Q8, however, the accuracy of the isoparametric quadrilateral elements will drop significantly due to mesh distortions. In a previouswork, we constructed an 8-node quadrilateral spline element L8 using the triangular area coordinates and the B-net method, which can be insensitive to mesh distortions and possess the second order completeness in the Cartesian coordinates. In this paper, a thin plate spline element is developed based on the spline element L8 and the refined technique. Numerical examples show that the present element indeed possesses higher accuracy than the DKQ element for distorted meshes.
11. Method for preparing surfaces of metal composites having a brittle phase for plating. [Patent application
DOEpatents
Coates, C.W.; Wilson, T.J.
1982-05-19
The present invention is directed to a method for preparing surfaces of two-phase metal composites having relatively brittle and malleable components for plating with corrosion-resistant material. In practice of the present invention, the surfaces of the composite are etched to remove a major portion or fraction of the brittle component. The etched surface is then peened with particulates for breaking the brittle component from the surfaces and for spreading or smearing the malleable component over the surfaces. The peened surface is then chemically cleaned of residual traces of the brittle component to which the corrosion-resistant material may be plated thereon in an adherent manner.
12. An imaging method of wavefront coding system based on phase plate rotation
Yi, Rigui; Chen, Xi; Dong, Liquan; Liu, Ming; Zhao, Yuejin; Liu, Xiaohua
2018-01-01
Wave-front coding has a great prospect in extending the depth of the optical imaging system and reducing optical aberrations, but the image quality and noise performance are inevitably reduced. According to the theoretical analysis of the wave-front coding system and the phase function expression of the cubic phase plate, this paper analyzed and utilized the feature that the phase function expression would be invariant in the new coordinate system when the phase plate rotates at different angles around the z-axis, and we proposed a method based on the rotation of the phase plate and image fusion. First, let the phase plate rotated at a certain angle around the z-axis, the shape and distribution of the PSF obtained on the image surface remain unchanged, the rotation angle and direction are consistent with the rotation angle of the phase plate. Then, the middle blurred image is filtered by the point spread function of the rotation adjustment. Finally, the reconstruction images were fused by the method of the Laplacian pyramid image fusion and the Fourier transform spectrum fusion method, and the results were evaluated subjectively and objectively. In this paper, we used Matlab to simulate the images. By using the Laplacian pyramid image fusion method, the signal-to-noise ratio of the image is increased by 19% 27%, the clarity is increased by 11% 15% , and the average gradient is increased by 4% 9% . By using the Fourier transform spectrum fusion method, the signal-to-noise ratio of the image is increased by 14% 23%, the clarity is increased by 6% 11% , and the average gradient is improved by 2% 6%. The experimental results show that the image processing by the above method can improve the quality of the restored image, improving the image clarity, and can effectively preserve the image information.
13. Plate measurement techniques and reduction methods used by the West German satellite observers, and resulting consequences for the observation
NASA Technical Reports Server (NTRS)
Deker, H.
1971-01-01
The West German tracking stations are equipped with ballistic cameras. Plate measurement and plate reduction must therefore follow photogrammetric methods. Approximately 100 star positions and 200 satellite positions are measured on each plate. The mathematical model for spatial rotation of the bundle of rays is extended by including terms for distortion and internal orientation of the camera as well as by providing terms for refraction which are computed for the measured coordinates of the star positions on the plate. From the measuring accuracy of the plate coordinates it follows that the timing accuracy for the exposures has to be about one millisecond, in order to obtain a homogeneous system.
14. About one counterexample of applying method of splitting in modeling of plating processes
Solovjev, D. S.; Solovjeva, I. A.; Litovka, Yu V.; Korobova, I. L.
2018-05-01
The paper presents the main factors that affect the uniformity of the thickness distribution of plating on the surface of the product. The experimental search for the optimal values of these factors is expensive and time-consuming. The problem of adequate simulation of coating processes is very relevant. The finite-difference approximation using seven-point and five-point templates in combination with the splitting method is considered as solution methods for the equations of the model. To study the correctness of the solution of equations of the mathematical model by these methods, the experiments were conducted on plating with a flat anode and cathode, which relative position was not changed in the bath. The studies have shown that the solution using the splitting method was up to 1.5 times faster, but it did not give adequate results due to the geometric features of the task under the given boundary conditions.
15. A method of vehicle license plate recognition based on PCANet and compressive sensing
Ye, Xianyi; Min, Feng
2018-03-01
The manual feature extraction of the traditional method for vehicle license plates has no good robustness to change in diversity. And the high feature dimension that is extracted with Principal Component Analysis Network (PCANet) leads to low classification efficiency. For solving these problems, a method of vehicle license plate recognition based on PCANet and compressive sensing is proposed. First, PCANet is used to extract the feature from the images of characters. And then, the sparse measurement matrix which is a very sparse matrix and consistent with Restricted Isometry Property (RIP) condition of the compressed sensing is used to reduce the dimensions of extracted features. Finally, the Support Vector Machine (SVM) is used to train and recognize the features whose dimension has been reduced. Experimental results demonstrate that the proposed method has better performance than Convolutional Neural Network (CNN) in the recognition and time. Compared with no compression sensing, the proposed method has lower feature dimension for the increase of efficiency.
16. Comparison of Exoelectrogenic Bacteria Detected Using Two Different Methods: U-tube Microbial Fuel Cell and Plating Method
PubMed Central
Yu, Jaecheul; Cho, Sunja; Kim, Sunah; Cho, Haein; Lee, Taeho
2012-01-01
In a microbial fuel cell (MFC), exoelectrogens, which transfer electrons to the electrode, have been regarded as a key factor for electricity generation. In this study, U-tube MFC and plating methods were used to isolate exoelectrogens from the anode of an MFC. Disparate microorganisms were identified depending on isolation methods, despite the use of an identical source. Denaturing gel gradient electrophoresis (DGGE) analysis showed that certain microorganisms became dominant in the U-tube MFC. The predominant bacterium was similar to Ochrobactrum sp., belonging to the Alphaproteobacteria, which was shown to be able to function as an exoelectrogen in a previous study. Three isolates, one affiliated with Bacillus sp. and two with Paenibacillus sp., were identified using the plating method, which belonged to the Gram-positive bacteria, the Firmicutes. The U-tube MFCs were inoculated with the three isolates using the plating method, operated in the batch mode and the current was monitored. All of the U-tube MFCs inoculated with each isolate after isolation from plates produced lower current (peak current density: 3.6–16.3 mA/m2) than those in U-tube MFCs with mixed culture (48.3–62.6 mA/m2). Although the isolates produced low currents, various bacterial groups were found to be involved in current production. PMID:22129603
17. Experimental measurements on transverse vibration characteristics of piezoceramic rectangular plates by optical methods
Ma, Chien-Ching; Lin, Hsien-Yang
2005-09-01
This study provides two non-contact optical techniques to investigate the transverse vibration characteristics of piezoceramic rectangular plates in resonance. These methods, including the amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) and laser Doppler vibrometer (LDV), are full-field measurement for AF-ESPI and point-wise displacement measurement for LDV, respectively. The edges of these piezoceramic rectangular plates may either be fixed or free. Both resonant frequencies and mode shapes of vibrating piezoceramic plates can be obtained simultaneously by AF-ESPI. Excellent quality of the interferometric fringe patterns for the mode shapes is obtained. In the LDV system, a built-in dynamic signal analyzer (DSA) composed of DSA software and a plug-in waveform generator board can provide the piezoceramic plates with the swept-sine excitation signal, whose gain at corresponding frequencies is analyzed by the DSA software. The peaks appeared in the frequency response curve are resonant frequencies. In addition to these optical methods, the numerical computation based on the finite element analysis is used to verify the experimental results. Good agreements of the mode shapes and resonant frequencies are obtained for experimental and numerical results.
18. Waves on Thin Plates: A New (Energy Based) Method on Localization
Turkaya, Semih; Toussaint, Renaud; Kvalheim Eriksen, Fredrik; Lengliné, Olivier; Daniel, Guillaume; Grude Flekkøy, Eirik; Jørgen Måløy, Knut
2016-04-01
Noisy acoustic signal localization is a difficult problem having a wide range of application. We propose a new localization method applicable for thin plates which is based on energy amplitude attenuation and inversed source amplitude comparison. This inversion is tested on synthetic data using a direct model of Lamb wave propagation and on experimental dataset (recorded with 4 Brüel & Kjær Type 4374 miniature piezoelectric shock accelerometers, 1 - 26 kHz frequency range). We compare the performance of this technique with classical source localization algorithms, arrival time localization, time reversal localization, localization based on energy amplitude. The experimental setup consist of a glass / plexiglass plate having dimensions of 80 cm x 40 cm x 1 cm equipped with four accelerometers and an acquisition card. Signals are generated using a steel, glass or polyamide ball (having different sizes) quasi perpendicular hit (from a height of 2-3 cm) on the plate. Signals are captured by sensors placed on the plate on different locations. We measure and compare the accuracy of these techniques as function of sampling rate, dynamic range, array geometry, signal to noise ratio and computational time. We show that this new technique, which is very versatile, works better than conventional techniques over a range of sampling rates 8 kHz - 1 MHz. It is possible to have a decent resolution (3cm mean error) using a very cheap equipment set. The numerical simulations allow us to track the contributions of different error sources in different methods. The effect of the reflections is also included in our simulation by using the imaginary sources outside the plate boundaries. This proposed method can easily be extended for applications in three dimensional environments, to monitor industrial activities (e.g boreholes drilling/production activities) or natural brittle systems (e.g earthquakes, volcanoes, avalanches).
19. A passive guard for low thermal conductivity measurement of small samples by the hot plate method
Jannot, Yves; Degiovanni, Alain; Grigorova-Moutiers, Veneta; Godefroy, Justine
2017-01-01
Hot plate methods under steady state conditions are based on a 1D model to estimate the thermal conductivity, using measurements of the temperatures T 0 and T 1 of the two sides of the sample and of the heat flux crossing it. To be consistent with the hypothesis of the 1D heat flux, either a hot plate guarded apparatus is used, or the temperature is measured at the centre of the sample. On one hand the latter method can be used only if the ratio thickness/width of the sample is sufficiently low and on the other hand the guarded hot plate method requires large width samples (typical cross section of 0.6 × 0.6 m2). That is why both methods cannot be used for low width samples. The method presented in this paper is based on an optimal choice of the temperatures T 0 and T 1 compared to the ambient temperature T a, enabling the estimation of the thermal conductivity with a centered hot plate method, by applying the 1D heat flux model. It will be shown that these optimal values do not depend on the size or on the thermal conductivity of samples (in the range 0.015-0.2 W m-1 K-1), but only on T a. The experimental results obtained validate the method for several reference samples for values of the ratio thickness/width up to 0.3, thus enabling the measurement of the thermal conductivity of samples having a small cross-section, down to 0.045 × 0.045 m2.
20. Method and apparatus for acoustic plate mode liquid-solid phase transition detection
DOEpatents
Blair, Dianna S.; Freye, Gregory C.; Hughes, Robert C.; Martin, Stephen J.; Ricco, Antonio J.
1993-01-01
A method and apparatus for sensing a liquid-solid phase transition event is provided which comprises an acoustic plate mode detecting element placed in contact with a liquid or solid material which generates a high-frequency acoustic wave that is attenuated to an extent based on the physical state of the material is contact with the detecting element. The attenuation caused by the material in contact with the acoustic plate mode detecting element is used to determine the physical state of the material being detected. The method and device are particularly suited for detecting conditions such as the icing and deicing of wings of an aircraft. In another aspect of the present invention, a method is provided wherein the adhesion of a solid material to the detecting element can be measured using the apparatus of the invention.
1. Crack Imaging and Quantification in Aluminum Plates with Guided Wave Wavenumber Analysis Methods
NASA Technical Reports Server (NTRS)
Yu, Lingyu; Tian, Zhenhua; Leckey, Cara A. C.
2015-01-01
Guided wavefield analysis methods for detection and quantification of crack damage in an aluminum plate are presented in this paper. New wavenumber components created by abrupt wave changes at the structural discontinuity are identified in the frequency-wavenumber spectra. It is shown that the new wavenumbers can be used to detect and characterize the crack dimensions. Two imaging based approaches, filter reconstructed imaging and spatial wavenumber imaging, are used to demonstrate how the cracks can be evaluated with wavenumber analysis. The filter reconstructed imaging is shown to be a rapid method to map the plate and any existing damage, but with less precision in estimating crack dimensions; while the spatial wavenumber imaging provides an intensity image of spatial wavenumber values with enhanced resolution of crack dimensions. These techniques are applied to simulated wavefield data, and the simulation based studies show that spatial wavenumber imaging method is able to distinguish cracks of different severities. Laboratory experimental validation is performed for a single crack case to confirm the methods' capabilities for imaging cracks in plates.
2. Three-beam interferogram analysis method for surface flatness testing of glass plates and wedges
Sunderland, Zofia; Patorski, Krzysztof
2015-09-01
When testing transparent plates with high quality flat surfaces and a small angle between them the three-beam interference phenomenon is observed. Since the reference beam and the object beams reflected from both the front and back surface of a sample are detected, the recorded intensity distribution may be regarded as a sum of three fringe patterns. Images of that type cannot be succesfully analyzed with standard interferogram analysis methods. They contain, however, useful information on the tested plate surface flatness and its optical thickness variations. Several methods were elaborated to decode the plate parameters. Our technique represents a competitive solution which allows for retrieval of phase components of the three-beam interferogram. It requires recording two images: a three-beam interferogram and the two-beam one with the reference beam blocked. Mutually subtracting these images leads to the intensity distribution which, under some assumptions, provides access to the two component fringe sets which encode surfaces flatness. At various stages of processing we take advantage of nonlinear operations as well as single-frame interferogram analysis methods. Two-dimensional continuous wavelet transform (2D CWT) is used to separate a particular fringe family from the overall interferogram intensity distribution as well as to estimate the phase distribution from a pattern. We distinguish two processing paths depending on the relative density of fringe sets which is connected with geometry of a sample and optical setup. The proposed method is tested on simulated data.
3. Developments in variational methods for high performance plate and shell elements
NASA Technical Reports Server (NTRS)
Felippa, Carlos A.; Militello, Carmelo
1991-01-01
High performance elements are simple finite elements constructed to deliver engineering accuracy with coarse arbitrary grids. This is part of a series on the variational foundations of high-performance elements, with emphasis on plate and shell elements constructed with the free formulation (FF) and assumed natural strain (ANS) methods. Parameterized variational principles are studied that provide a common foundation for the FF and ANS methods, as well as for a combination of both. From this unified formulation a variant of the ANS formulation, called the assumed natural deviatoric strain (ANDES) formulation, emerges as an important special case. The first ANDES element, a high-performance 9 degrees of freedom triangular Kirchhoff plate bending element, is briefly described to illustrate the use of the new formulation.
4. Method for measuring retardation of infrared wave-plate by modulated-polarized visible light
Zhang, Ying; Song, Feijun
2012-11-01
A new method for precisely measuring the optical phase retardation of wave-plates in the infrared spectral region is presented by using modulated-polarized visible light. An electro-optic modulator is used to accurately determine the zero point by the frequency-doubled signal of the Modulated-polarized light. A Babinet-Soleil compensator is employed to make the phase delay compensation. Based on this method, an instrument is set up to measure the retardations of the infrared wave-plates with visible region laser. Measurement results with high accuracy and sound repetition are obtained by simple calculation. Its measurement precision is less than and repetitive precision is within 0.3%.
5. Optimisation of a direct plating method for the detection and enumeration of Alicyclobacillus acidoterrestris spores.
PubMed
Henczka, Marek; Djas, Małgorzata; Filipek, Katarzyna
2013-01-01
A direct plating method for the detection and enumeration of Alicyclobacillus acidoterrestris spores has been optimised. The results of the application of four types of growth media (BAT agar, YSG agar, K agar and SK agar) regarding the recovery and enumeration of A. acidoterrestris spores were compared. The influence of the type of applied growth medium, heat shock conditions, incubation temperature, incubation time, plating technique and the presence of apple juice in the sample on the accuracy of the detection and enumeration of A. acidoterrestris spores was investigated. Among the investigated media, YSG agar was the most sensitive medium, and its application resulted in the highest recovery of A. acidoterrestris spores, while K agar and BAT agar were the least suitable media. The effect of the heat shock time on the recovery of spores was negligible. When there was a low concentration of spores in a sample, the membrane filtration method was superior to the spread plating method. The obtained results show that heat shock carried out at 80°C for 10 min and plating samples in combination with membrane filtration on YSG agar, followed by incubation at 46°C for 3 days provided the optimal conditions for the detection and enumeration of A. acidoterrestris spores. Application of the presented method allows highly efficient, fast and sensitive identification and enumeration of A. acidoterrestris spores in food products. This methodology will be useful for the fruit juice industry for identifying products contaminated with A. acidoterrestris spores, and its practical application may prevent economic losses for manufacturers. Copyright © 2012 Elsevier B.V. All rights reserved.
6. Disinfection of Escherichia coli bacteria using hybrid method of ozonation and hydrodynamic cavitation with orifice plate
Karamah, Eva F.; Ghaudenson, Rioneli; Amalia, Fitri; Bismo, Setijo
2017-11-01
This research aims to evaluate the performance of hybrid method of ozonation and hydrodynamic cavitation with orifice plate on E.coli bacteria disinfection. In this research, ozone dose, circulation flowrate, and disinfection method were varied. Ozone was produced by commercial ozonator with ozone dose of 64.83 mg/hour, 108.18 mg/hour, and 135.04 mg/hour. Meanwhile, hydrodynamic cavitation was generated by an orifice plate. The disinfection method compared in this research were: hydrodynamic cavitation, ozonation, and the combination of both. The best result on each method was achieved on the 60th minutes and with a circulation flowrate of 7 L/min. The hybrid method attained final concentration of 0 CFU/mL from the initial concentration of 2.10 × 105 CFU/mL. The ozonation method attained final concentration of 0 CFU/mL from the initial concentration of 1.32 × 105 CFU/mL. Cavitation method gives the least disinfection with final concentration of 5.20 × 104 CFU/mL from the initial concentration of 2.17 × 105 CFU/mL. In conclusion, hybrid method gives a faster and better disinfection of E.coli than each method on its own.
7. Method for preparing surfaces of metal composites having a brittle phase for plating
DOEpatents
Coates, Cameron W.; Wilson, Thomas J.
1984-01-01
The present invention is directed to a method for preparing surfaces of two-phase metal composites having relatively brittle and malleable components for plating with corrosion-resistant material. In practice of the present invention, the surfaces of the composites are etched to remove a major portion or fraction of the brittle component. The etched surface is then peened with particulates for breaking the brittle component from the surfaces and for spreading or smearing the malleable component over the surfaces. The peened surface is then chemically cleaned of residual traces of the brittle component so as to provide a surface of essentially the malleable component to which the corrosion-resistant material may be plated thereon in an adherent manner.
8. Methodes de calcul des forces aerodynamiques pour les etudes des interactions aeroservoelastiques
Biskri, Djallel Eddine
L'aeroservoelasticite est un domaine ou interagissent la structure flexible d'un avion, l'aerodynamique et la commande de vol. De son cote, la commande du vol considere l'avion comme une structure rigide et etudie l'influence du systeme de commande sur la dynamique de vol. Dans cette these, nous avons code trois nouvelles methodes d'approximation de forces aerodynamiques: Moindres carres corriges, Etat minimal corrige et Etats combines. Dans les deux premieres methodes, les erreurs d'approximation entre les forces aerodynamiques approximees par les methodes classiques et celles obtenues par les nouvelles methodes ont les memes formes analytiques que celles des forces aerodynamiques calculees par LS ou MS. Quant a la troisieme methode, celle-ci combine les formulations des forces approximees avec les methodes standards LS et MS. Les vitesses et frequences de battement et les temps d'executions calcules par les nouvelles methodes versus ceux calcules par les methodes classiques ont ete analyses.
9. Developpement d'une methode calorimetrique de mesure des pertes ac pour des rubans supraconducteurs a haute temperature critique
Dolez, Patricia
Le travail de recherche effectue dans le cadre de ce projet de doctorat a permis la mise au point d'une methode de mesure des pertes ac destinee a l'etude des supraconducteurs a haute temperature critique. Pour le choix des principes de cette methode, nous nous sommes inspires de travaux anterieurs realises sur les supraconducteurs conventionnels, afin de proposer une alternative a la technique electrique, presentant lors du debut de cette these des problemes lies a la variation du resultat des mesures selon la position des contacts de tension sur la surface de l'echantillon, et de pouvoir mesurer les pertes ac dans des conditions simulant la realite des futures applications industrielles des rubans supraconducteurs: en particulier, cette methode utilise la technique calorimetrique, associee a une calibration simultanee et in situ. La validite de la methode a ete verifiee de maniere theorique et experimentale: d'une part, des mesures ont ete realisees sur des echantillons de Bi-2223 recouverts d'argent ou d'alliage d'argent-or et comparees avec les predictions theoriques donnees par Norris, nous indiquant la nature majoritairement hysteretique des pertes ac dans nos echantillons; d'autre part, une mesure electrique a ete realisee in situ dont les resultats correspondent parfaitement a ceux donnes par notre methode calorimetrique. Par ailleurs, nous avons compare la dependance en courant et en frequence des pertes ac d'un echantillon avant et apres qu'il ait ete endommage. Ces mesures semblent indiquer une relation entre la valeur du coefficient de la loi de puissance modelisant la dependance des pertes avec le courant, et les inhomogeneites longitudinales du courant critique induites par l'endommagement. De plus, la variation en frequence montre qu'au niveau des grosses fractures transverses creees par l'endommagement dans le coeur supraconducteur, le courant se partage localement de maniere a peu pres equivalente entre les quelques grains de matiere
10. A Comprehensive Study of Internal Distraction Plating, an Alternative Method for Distal Radius Fractures.
PubMed
Jain, Mohit J; Mavani, Kinjal J
2016-12-01
11. Depth compensating calculation method of computer-generated holograms using symmetry and similarity of zone plates
Wei, Hui; Gong, Guanghong; Li, Ni
2017-10-01
Computer-generated hologram (CGH) is a promising 3D display technology while it is challenged by heavy computation load and vast memory requirement. To solve these problems, a depth compensating CGH calculation method based on symmetry and similarity of zone plates is proposed and implemented on graphics processing unit (GPU). An improved LUT method is put forward to compute the distances between object points and hologram pixels in the XY direction. The concept of depth compensating factor is defined and used for calculating the holograms of points with different depth positions instead of layer-based methods. The proposed method is suitable for arbitrary sampling objects with lower memory usage and higher computational efficiency compared to other CGH methods. The effectiveness of the proposed method is validated by numerical and optical experiments.
12. Methods of Fabricating a Layer of Metallic Glass-Based Material Using Immersion and Pouring Techniques
NASA Technical Reports Server (NTRS)
Hofmann, Douglas (Inventor)
2015-01-01
Systems and methods in accordance with embodiments of the invention implement layers of metallic glass-based materials. In one embodiment, a method of fabricating a layer of metallic glass includes: applying a coating layer of liquid phase metallic glass to an object, the coating layer being applied in a sufficient quantity such that the surface tension of the liquid phase metallic glass causes the coating layer to have a smooth surface; where the metallic glass has a critical cooling rate less than 1000 K/s; and cooling the coating layer of liquid phase metallic glass to form a layer of solid phase metallic glass.
13. Apparatus and method for explosive bonding to edge of flyer plate
NASA Technical Reports Server (NTRS)
Bement, Laurence J. (Inventor); Kushnick, Anne C. (Inventor)
1991-01-01
The invention is an apparatus and a process for the explosive joining of a flyer plate and a base plate. The apparatus consists of a flyer plate positioned over a base plate. The flyer plate has a notch containing a filler material in intimate contact with the flyer plate. An adhesive means holds a ribbon explosive partially overlapping the notch in the flyer plate. A detonating means initiates the ribbon explosive that drives the flyer plate to accomplish a high velocity, angular collision between the mating surfaces. This collision creates surface melts and effacing bonding, resulting in electron sharing linkups between the plates. An unbonded tab fractures at a base of the notch leaving a bond to an edge of the attached flyer plate.
14. An Investigation into the Application of Generalized Differential Quadrature Method to Bending Analysis of Composite Sandwich Plates
Ghassemi, Aazam; Yazdani, Mostafa; Hedayati, Mohamad
2017-12-01
In this work, based on the First Order Shear Deformation Theory (FSDT), an attempt is made to explore the applicability and accuracy of the Generalized Differential Quadrature Method (GDQM) for bending analysis of composite sandwich plates under static loading. Comparative studies of the bending behavior of composite sandwich plates are made between two types of boundary conditions for different cases. The effects of fiber orientation, ratio of thickness to length of the plate, the ratio of thickness of core to thickness of the face sheet are studied on the transverse displacement and moment resultants. As shown in this study, the role of the core thickness in deformation of these plates can be reversed by the stiffness of the core in comparison with sheets. The obtained graphs give very good results due to optimum design of sandwich plates. In Comparison with existing solutions, fast convergent rates and high accuracy results can be achieved by the GDQ method.
15. The analysis of the accuracy of the wheel alignment inspection method on the side-slip plate stand
Gajek, A.; Strzępek, P.
2016-09-01
The article presents the theoretical basis and the results of the examination of the wheel alignment inspection method on the slide slip plate stand. It is obligatory test during periodic technical inspection of the vehicle. The measurement is executed in the dynamic conditions. The dependence between the lateral displacement of the plate and toe-in of the tested wheels has been shown. If the diameter of the wheel rim is known then the value of the toe-in can be calculated. The comparison of the toe-in measurements on the plate stand and on the four heads device for the wheel alignment inspection has been carried out. The accuracy of the measurements and the influence of the conditions of the tests on the plate stand (the way of passing through the plate) were estimated. The conclusions about the accuracy of this method are presented.
16. Methodes de decomposition pour la planification a moyen terme de la production hydroelectrique sous incertitude
Carpentier, Pierre-Luc
In this thesis, we consider the midterm production planning problem (MTPP) of hydroelectricity generation under uncertainty. The aim of this problem is to manage a set of interconnected hydroelectric reservoirs over several months. We are particularly interested in high dimensional reservoir systems that are operated by large hydroelectricity producers such as Hydro-Quebec. The aim of this thesis is to develop and evaluate different decomposition methods for solving the MTPP under uncertainty. This thesis is divided in three articles. The first article demonstrates the applicability of the progressive hedging algorithm (PHA), a scenario decomposition method, for managing hydroelectric reservoirs with multiannual storage capacity under highly variable operating conditions in Canada. The PHA is a classical stochastic optimization method designed to solve general multistage stochastic programs defined on a scenario tree. This method works by applying an augmented Lagrangian relaxation on non-anticipativity constraints (NACs) of the stochastic program. At each iteration of the PHA, a sequence of subproblems must be solved. Each subproblem corresponds to a deterministic version of the original stochastic program for a particular scenario in the scenario tree. Linear and a quadratic terms must be included in subproblem's objective functions to penalize any violation of NACs. An important limitation of the PHA is due to the fact that the number of subproblems to be solved and the number of penalty terms increase exponentially with the branching level in the tree. This phenomenon can make the application of the PHA particularly difficult when the scenario tree covers several tens of time periods. Another important limitation of the PHA is caused by the fact that the difficulty level of NACs generally increases as the variability of scenarios increases. Consequently, applying the PHA becomes particularly challenging in hydroclimatic regions that are characterized by a high
17. Shape sensing methods: Review and experimental comparison on a wing-shaped plate
Gherlone, Marco; Cerracchio, Priscilla; Mattone, Massimiliano
2018-05-01
Shape sensing, i.e., the reconstruction of the displacement field of a structure from some discrete surface strain measurements, is a fundamental capability for the structural health management of critical components. In this paper, a review of the shape sensing methodologies available in the open literature and of the different applications is provided. Then, for the first time, an experimental comparative study is presented among the main approaches in order to highlight their relative merits in presence of uncertainties affecting real applications. These approaches are, namely, the inverse Finite Element Method, the Modal Method and Ko's Displacement Theory. A brief description of these methods is followed by the presentation of the experimental test results. A cantilevered, wing-shaped aluminum plate is let deform under its own weight, leading to bending and twisting. Using the experimental strain measurements as input data, the deflection field of the plate is reconstructed using the three aforementioned approaches and compared with the actual measured deflection. The inverse Finite Element Method is proven to be slightly more accurate and particularly attractive because it is versatile with respect to the boundary conditions and it does not require any information about material properties and loading conditions.
18. An encoding readout method used for Multi-gap Resistive Plate Chambers (MRPCs) for muon tomography
Yue, X.; Zeng, M.; Wang, Y.; Wang, X.; Zeng, Z.; Zhao, Z.; Cheng, J.
2014-09-01
A muon tomography facility has been built in Tsinghua University. Because of the low flux of cosmic muon, an encoding readout method, based on the fine-fine configuration, was implemented for the 2880 channels induced signals from the Multi-gap Resistive Plate Chamber (MRPC) detectors. With the encoding method, the number of the readout electronics was dramatically reduced and thus the complexity and the cost of the facility was reduced, too. In this paper, the details of the encoding method, and the overall readout system setup in the muon tomography facility are described. With the commissioning of the facility, the readout method works well. The spatial resolution of all MRPC detectors are measured with cosmic muon and the preliminary imaging result are also given.
19. Numerical Manifold Method for the Forced Vibration of Thin Plates during Bending
PubMed Central
Jun, Ding; Song, Chen; Wei-Bin, Wen; Shao-Ming, Luo; Xia, Huang
2014-01-01
A novel numerical manifold method was derived from the cubic B-spline basis function. The new interpolation function is characterized by high-order coordination at the boundary of a manifold element. The linear elastic-dynamic equation used to solve the bending vibration of thin plates was derived according to the principle of minimum instantaneous potential energy. The method for the initialization of the dynamic equation and its solution process were provided. Moreover, the analysis showed that the calculated stiffness matrix exhibited favorable performance. Numerical results showed that the generalized degrees of freedom were significantly fewer and that the calculation accuracy was higher for the manifold method than for the conventional finite element method. PMID:24883403
20. Simulation of moving flat plate with unsteady translational motion using vortex method
Widodo, A. F.; Zuhal, L. R.
2013-10-01
This paper presents simulation of moving flate plate with unsteady translational motion using Lagrangianmeshless numerical simulation named vortex method. The method solves Navier-Stokes equations in term of vorticity. The solving strategy is splitting the equation into diffusion and convection term to be solved separately. The diffusion term is modeled by particles strength exchange(PSE) which is the most accurate of diffusion modeling in vortex method. The convection term that represents transport of particles is calculated by time step integration of velocity. Velocity of particles is natively calculated using Biot-Savart relation but for acceleration, fastmultiple method(FMM) is employed. The simulation is validated experimentally using digital particle image velocimetry(DPIV) and the results give good agreement.
1. A 2D Daubechies finite wavelet domain method for transient wave response analysis in shear deformable laminated composite plates
Nastos, C. V.; Theodosiou, T. C.; Rekatsinas, C. S.; Saravanos, D. A.
2018-03-01
An efficient numerical method is developed for the simulation of dynamic response and the prediction of the wave propagation in composite plate structures. The method is termed finite wavelet domain method and takes advantage of the outstanding properties of compactly supported 2D Daubechies wavelet scaling functions for the spatial interpolation of displacements in a finite domain of a plate structure. The development of the 2D wavelet element, based on the first order shear deformation laminated plate theory is described and equivalent stiffness, mass matrices and force vectors are calculated and synthesized in the wavelet domain. The transient response is predicted using the explicit central difference time integration scheme. Numerical results for the simulation of wave propagation in isotropic, quasi-isotropic and cross-ply laminated plates are presented and demonstrate the high spatial convergence and problem size reduction obtained by the present method.
2. High-Temperature Thermal Conductivity Measurement Apparatus Based on Guarded Hot Plate Method
Turzo-Andras, E.; Magyarlaki, T.
2017-10-01
An alternative calibration procedure has been applied using apparatus built in-house, created to optimize thermal conductivity measurements. The new approach compared to those of usual measurement procedures of thermal conductivity by guarded hot plate (GHP) consists of modified design of the apparatus, modified position of the temperature sensors and new conception in the calculation method, applying the temperature at the inlet section of the specimen instead of the temperature difference across the specimen. This alternative technique is suitable for eliminating the effect of thermal contact resistance arising between a rigid specimen and the heated plate, as well as accurate determination of the specimen temperature and of the heat loss at the lateral edge of the specimen. This paper presents an overview of the specific characteristics of the newly developed "high-temperature thermal conductivity measurement apparatus" based on the GHP method, as well as how the major difficulties are handled in the case of this apparatus, as compared to the common GHP method that conforms to current international standards.
3. Method of producing exfoliated graphite composite compositions for fuel cell flow field plates
DOEpatents
Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z
2014-04-08
A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.
4. Quantification of the spatial strain distribution of scoliosis using a thin-plate spline method.
PubMed
Kiriyama, Yoshimori; Watanabe, Kota; Matsumoto, Morio; Toyama, Yoshiaki; Nagura, Takeo
2014-01-03
The objective of this study was to quantify the three-dimensional spatial strain distribution of a scoliotic spine by nonhomogeneous transformation without using a statistically averaged reference spine. The shape of the scoliotic spine was determined from computed tomography images from a female patient with adolescent idiopathic scoliosis. The shape of the scoliotic spine was enclosed in a rectangular grid, and symmetrized using a thin-plate spline method according to the node positions of the grid. The node positions of the grid were determined by numerical optimization to satisfy symmetry. The obtained symmetric spinal shape was enclosed within a new rectangular grid and distorted back to the original scoliotic shape using a thin-plate spline method. The distorted grid was compared to the rectangular grid that surrounded the symmetrical spine. Cobb's angle was reduced from 35° in the scoliotic spine to 7° in the symmetrized spine, and the scoliotic shape was almost fully symmetrized. The scoliotic spine showed a complex Green-Lagrange strain distribution in three dimensions. The vertical and transverse compressive/tensile strains in the frontal plane were consistent with the major scoliotic deformation. The compressive, tensile and shear strains on the convex side of the apical vertebra were opposite to those on the concave side. These results indicate that the proposed method can be used to quantify the three-dimensional spatial strain distribution of a scoliotic spine, and may be useful in quantifying the deformity of scoliosis. © 2013 Elsevier Ltd. All rights reserved.
5. Silver-halide sensitized gelatin (SHSG) processing method for pulse holograms recorded on VRP plates
Evstigneeva, Maria K.; Drozdova, Olga V.; Mikhailov, Viktor N.
2002-06-01
One of the most important area of holograph applications is display holography. In case of pulse recording the requirement for vibration stability is easier than compared to CW exposure. At the same time it is widely known that the behavior of sliver-halide holographic materials strongly depends on the exposure duration. In particular the exposure sensitivity drastically decreases under nanosecond pulse duration. One of the effective ways of the diffraction efficiency improvement is SHSG processing method. This processing scheme is based on high modulation of refractive index due to microvoids appearance inside emulsion layer. It should be mentioned that the SHSG method was used earlier only in the cases when the holograms were recorded by use of CW lasers. This work is devoted to the investigation of SHSG method for pulse hologram recording on VRP plates. We used a pulsed YLF:Nd laser with pulse duration of 25 nanoseconds and wavelength of 527 nm. Both transmission and reflection holograms were recorded. The different kinds of bleaching as well as developing solutions were investigated. Our final processing scheme includes the following stages: 1) development in non-tanning solution, 2) rehalogenating bleach, 3) intermediate alcohol drying, 4) uniform second exposure, 5) second development in diluted developer, 6) reverse bleaching, 7) fixing and 8) gradient drying in isopropyl alcohol. Diffraction efficiency of transmission holograms was of about 60 percent and reflection mirror holograms was of about 45 percent. Thus we have demonstrated the SHSG processing scheme for producing effective holograms on VRP plates under pulse exposure.
6. The frequency-domain method of calculation for the pulsed electromagnetic field in a conductive ferromagnetic plate
Nosov, G. V.; Kuleshova, E. O.; Lefebvre, S.; Plyusnin, A. A.; Tokmashev, D. M.
2017-02-01
The technique for parameters determination of magnetic skin effect on ferromagnetic plate at a specified pulse of magnetic field intensity on the plate surface is proposed. It is based on a frequency-domain method and could be applied for a pulsing transformer, a dynamoelectric pulse generator and a commutating inductor that contains an imbricated core. Due to this technique, such plate parameters as specific heat loss energy, the average power of this energy and the plate temperature raise, the magnetic flux attenuation factor and the plate q-factor could be calculated. These parameters depend on the steel type, the amplitude, the rms value, the duration and the form of the magnetic field intensity impulse on the plate surface. The plate thickness is defined by the value of the flux attenuation factor and the plate q-factor that should be maximal. The reliability of the proposed technique is built on a common frequency-domain usage applicable for pulse transient study under zero boundary conditions of the electric circuit and the conformity of obtained results with the sinusoidal steady-state mode.
7. Vectorization and parallelization of the finite strip method for dynamic Mindlin plate problems
NASA Technical Reports Server (NTRS)
Chen, Hsin-Chu; He, Ai-Fang
1993-01-01
The finite strip method is a semi-analytical finite element process which allows for a discrete analysis of certain types of physical problems by discretizing the domain of the problem into finite strips. This method decomposes a single large problem into m smaller independent subproblems when m harmonic functions are employed, thus yielding natural parallelism at a very high level. In this paper we address vectorization and parallelization strategies for the dynamic analysis of simply-supported Mindlin plate bending problems and show how to prevent potential conflicts in memory access during the assemblage process. The vector and parallel implementations of this method and the performance results of a test problem under scalar, vector, and vector-concurrent execution modes on the Alliant FX/80 are also presented.
8. A Weak Galerkin Method for the Reissner–Mindlin Plate in Primary Form
DOE PAGES
Mu, Lin; Wang, Junping; Ye, Xiu
2017-10-04
We developed a new finite element method for the Reissner–Mindlin equations in its primary form by using the weak Galerkin approach. Like other weak Galerkin finite element methods, this one is highly flexible and robust by allowing the use of discontinuous approximating functions on arbitrary shape of polygons and, at the same time, is parameter independent on its stability and convergence. Furthermore, error estimates of optimal order in mesh size h are established for the corresponding weak Galerkin approximations. Numerical experiments are conducted for verifying the convergence theory, as well as suggesting some superconvergence and a uniform convergence of themore » method with respect to the plate thickness.« less
9. A Weak Galerkin Method for the Reissner–Mindlin Plate in Primary Form
SciTech Connect
Mu, Lin; Wang, Junping; Ye, Xiu
We developed a new finite element method for the Reissner–Mindlin equations in its primary form by using the weak Galerkin approach. Like other weak Galerkin finite element methods, this one is highly flexible and robust by allowing the use of discontinuous approximating functions on arbitrary shape of polygons and, at the same time, is parameter independent on its stability and convergence. Furthermore, error estimates of optimal order in mesh size h are established for the corresponding weak Galerkin approximations. Numerical experiments are conducted for verifying the convergence theory, as well as suggesting some superconvergence and a uniform convergence of themore » method with respect to the plate thickness.« less
10. Studies on prevalence of Strongyloides infection in Holambra and Maceió, Brazil, by the agar plate faecal culture method.
PubMed
Kobayashi, J; Hasegawa, H; Soares, E C; Toma, H; Dacal, A R; Brito, M C; Yamanaka, A; Foli, A A; Sato, Y
1996-01-01
Prevalence of Strongyloides stercoralis infection in three areas of Brazil was surveyed by a recently developed faecal culture method (an agar plate culture). The Strongyloides infection was confirmed in 11.3% of 432 subjects examined. The diagnostic efficacy of the agar plate culture was as high as 93.9% compared to only 28.5% and 26.5% by the Harada-Mori filter paper culture and faecal concentration methods, when faecal samples were examined simultaneously by these three methods. Among the 49 positive samples, about 60% were confirmed to be positive only by the agar plate culture. These results indicate that the agar plate culture is a sensitive new tool for the correct diagnosis of chronic Strongyloides infection.
11. Facile synthesis of Co3O4 hexagonal plates by flux method
Han, Ji-Long; Meng, Qing-Fen; Gao, Sheng-Li
2018-01-01
Using a novel flux method, a hexagonal plate of Co3O4 was directly synthesized. In this method, CoCl2·6H2O, NaOH, and the cosolvent H3BO3 were heated to 750 °C for 2 h in a corundum crucible. The products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high-resolution transmission electron microscope (HRTEM). Furthermore, XRD studies indicated that the product consisted of a cubic phase of Co3O4, and the phase existed in a completely crystalline form. Then, SEM results indicated that these hexagonal plates tiered up and they had diameters in the range of 2-10 μm. According to the results of SAED and HRTEM analyses, the interlayer spacing was about 0.24 nm, which corresponds to the interlayer distance of (3 1 1) crystal plane of cubic Co3O4.
12. Orifice plate for controlling solids flow, methods of use thereof and articles comprising the same
SciTech Connect
Jukkola, Glen D.; Teigen, Bard C.
Disclosed herein is an orifice plate comprising one or more plates having orifices disposed therein; the orifices being operative to permit the flow of solids from a moving bed heat exchanger to a solids flow control system; where the orifice plate is downstream of a tube bundle of the moving bed heat exchanger and upstream of the solids flow control system and wherein the orifice plate is operative to evenly distribute the flow of solids in the solids flow control system.
13. A simple method to ensure proper screw position and plate size selection using the Morscher cervical spine locking plate. Technical note.
PubMed
Ball, P A; Benzel, E C; Baldwin, N G
1994-04-01
The use of bone plate instrumentation with screw fixation has proved to be a useful adjunctive measure in anterior cervical spine fusion surgery. Proper fitting, positioning, and attachment of this instrumentation have been shown to be frequently suboptimal if done without radiographic guidance. The most commonly used method of radiographic assistance for placement of this instrumentation is fluoroscopy. While this gives satisfactory technical results, it is expensive and time-consuming, and exposes the patient and the operating room personnel to ionizing radiation. The authors present a simple technique to ensure screw placement and plate fitting using Kirschner wires and a single lateral radiograph. This technique saves time, reduces exposure to radiation, and has led to satisfactory results in over 20 operative cases.
14. A novel diagnosis method for a Hall plates-based rotary encoder with a magnetic concentrator.
PubMed
Meng, Bumin; Wang, Yaonan; Sun, Wei; Yuan, Xiaofang
2014-07-31
In the last few years, rotary encoders based on two-dimensional complementary metal oxide semiconductors (CMOS) Hall plates with a magnetic concentrator have been developed to measure contactless absolute angle. There are various error factors influencing the measuring accuracy, which are difficult to locate after the assembly of encoder. In this paper, a model-based rapid diagnosis method is presented. Based on an analysis of the error mechanism, an error model is built to compare minimum residual angle error and to quantify the error factors. Additionally, a modified particle swarm optimization (PSO) algorithm is used to reduce the calculated amount. The simulation and experimental results show that this diagnosis method is feasible to quantify the causes of the error and to reduce iteration significantly.
15. A cylinder-plate method for microbiological assay of clavulanic acid.
PubMed
Hamedi, J; Shahverdi, A R; Samadi, N; Mohammadi, A; Shiran, M; Akhondi, S
2006-12-01
Clavulanic acid is a natural occurring beta-lactam product of Streptomyces clavuligerus and is a potent inhibitor of bacterial beta-lactamases. The present work reports a microbiological assay based on the cylinder-plate method for determination of clavulanic acid. The assay is based on the inhibitory effect of clavulanic acid in combination with penicillin G upon Escherichia coli ATCC 35218, which is used as the test organism. The correlation between clavulanic acid concentration and the inhibitory effect on E. coli was linear (r > 0.99) and in the range of 8-20 microg/ml. These results indicate that the proposed method is appropriate for the determination of clavulanic acid in commercial samples and can be used in routine quality control.
16. Comparison of Primary Models to Predict Microbial Growth by the Plate Count and Absorbance Methods.
PubMed
Pla, María-Leonor; Oltra, Sandra; Esteban, María-Dolores; Andreu, Santiago; Palop, Alfredo
2015-01-01
The selection of a primary model to describe microbial growth in predictive food microbiology often appears to be subjective. The objective of this research was to check the performance of different mathematical models in predicting growth parameters, both by absorbance and plate count methods. For this purpose, growth curves of three different microorganisms (Bacillus cereus, Listeria monocytogenes, and Escherichia coli) grown under the same conditions, but with different initial concentrations each, were analysed. When measuring the microbial growth of each microorganism by optical density, almost all models provided quite high goodness of fit (r(2) > 0.93) for all growth curves. The growth rate remained approximately constant for all growth curves of each microorganism, when considering one growth model, but differences were found among models. Three-phase linear model provided the lowest variation for growth rate values for all three microorganisms. Baranyi model gave a variation marginally higher, despite a much better overall fitting. When measuring the microbial growth by plate count, similar results were obtained. These results provide insight into predictive microbiology and will help food microbiologists and researchers to choose the proper primary growth predictive model.
17. Methods and formulas for calculating the strength of plate and shell constructions as used in airplane design
NASA Technical Reports Server (NTRS)
Heck, O S; Ebner, H
1936-01-01
This report is a compilation of previously published articles on formulas and methods of calculation for the determination of the strength and stability of plate and shell construction as employed in airplane design. In particular, it treats the problem of isotropic, orthotopic, and stiffened rectangular plates, thin curved panels, and circular cylinders under various loading conditions. The purpose of appending the pertinent literature references following the subjects discussed was to facilitate a comprehensive study of the treated problems.
18. Reconstruction of transient vibration and sound radiation of an impacted plate using time domain plane wave superposition method
Geng, Lin; Zhang, Xiao-Zheng; Bi, Chuan-Xing
2015-05-01
Time domain plane wave superposition method is extended to reconstruct the transient pressure field radiated by an impacted plate and the normal acceleration of the plate. In the extended method, the pressure measured on the hologram plane is expressed as a superposition of time convolutions between the time-wavenumber normal acceleration spectrum on a virtual source plane and the time domain propagation kernel relating the pressure on the hologram plane to the normal acceleration spectrum on the virtual source plane. By performing an inverse operation, the normal acceleration spectrum on the virtual source plane can be obtained by an iterative solving process, and then taken as the input to reconstruct the whole pressure field and the normal acceleration of the plate. An experiment of a clamped rectangular steel plate impacted by a steel ball is presented. The experimental results demonstrate that the extended method is effective in visualizing the transient vibration and sound radiation of an impacted plate in both time and space domains, thus providing the important information for overall understanding the vibration and sound radiation of the plate.
19. Experimental comparison and validation of hot-ball method with guarded hot plate method on polyurethane foams
Hudec, Ján; Glorieux, Christ; Dieška, Peter; Kubičár, Ľudovít
2016-07-01
The Hot-ball method is an innovative transient method for measuring thermophysical properties. The principle is based on heating of a small ball, incorporated in measured medium, by constant heating power and simultaneous measuring of the ball's temperature response since the heating was initiated. The shape of the temperature response depends on thermophysical properties of the medium, where the sensor is placed. This method is patented by Institute of Physics, SAS, where the method and sensors based on this method are being developed. At the beginning of the development of sensors for this method we were oriented on monitoring applications, where relative precision is much more important than accuracy. Meanwhile, the quality of sensors was improved good enough to be used for a new application - absolute measuring of thermophysical parameters of low thermally conductive materials. This paper describes experimental verification and validation of measurement by hot-ball method. Thanks to cooperation with Laboratory of Soft Matter and Biophysics of Catholic University of Leuven in Belgium, established Guarded Hot Plate method was used as a reference. Details about measuring setups, description of the experiments and results of the comparison are presented.
20. High accuracy position response calibration method for a micro-channel plate ion detector
Hong, R.; Leredde, A.; Bagdasarova, Y.; Fléchard, X.; García, A.; Müller, P.; Knecht, A.; Liénard, E.; Kossin, M.; Sternberg, M. G.; Swanson, H. E.; Zumwalt, D. W.
2016-11-01
We have developed a position response calibration method for a micro-channel plate (MCP) detector with a delay-line anode position readout scheme. Using an in situ calibration mask, an accuracy of 8 μm and a resolution of 85 μm (FWHM) have been achieved for MeV-scale α particles and ions with energies of ∼10 keV. At this level of accuracy, the difference between the MCP position responses to high-energy α particles and low-energy ions is significant. The improved performance of the MCP detector can find applications in many fields of AMO and nuclear physics. In our case, it helps reducing systematic uncertainties in a high-precision nuclear β-decay experiment.
1. Applying electric field to charged and polar particles between metallic plates: extension of the Ewald method.
PubMed
Takae, Kyohei; Onuki, Akira
2013-09-28
We develop an efficient Ewald method of molecular dynamics simulation for calculating the electrostatic interactions among charged and polar particles between parallel metallic plates, where we may apply an electric field with an arbitrary size. We use the fact that the potential from the surface charges is equivalent to the sum of those from image charges and dipoles located outside the cell. We present simulation results on boundary effects of charged and polar fluids, formation of ionic crystals, and formation of dipole chains, where the applied field and the image interaction are crucial. For polar fluids, we find a large deviation of the classical Lorentz-field relation between the local field and the applied field due to pair correlations along the applied field. As general aspects, we clarify the difference between the potential-fixed and the charge-fixed boundary conditions and examine the relationship between the discrete particle description and the continuum electrostatics.
2. Piezoelectrically forced vibrations of electroded doubly rotated quartz plates by state space method
NASA Technical Reports Server (NTRS)
Chander, R.
1990-01-01
The purpose of this investigation is to develop an analytical method to study the vibration characteristics of piezoelectrically forced quartz plates. The procedure can be summarized as follows. The three dimensional governing equations of piezoelectricity, the constitutive equations and the strain-displacement relationships are used in deriving the final equations. For this purpose, a state vector consisting of stresses and displacements are chosen and the above equations are manipulated to obtain the projection of the derivative of the state vector with respect to the thickness coordinate on to the state vector itself. The solution to the state vector at any plane is then easily obtained in a closed form in terms of the state vector quantities at a reference plane. To simplify the analysis, simple thickness mode and plane strain approximations are used.
3. Single Transducer Ultrasonic Imaging Method that Eliminates the Effect of Plate Thickness Variation in the Image
NASA Technical Reports Server (NTRS)
Roth, Don J.
1996-01-01
This article describes a single transducer ultrasonic imaging method that eliminates the effect of plate thickness variation in the image. The method thus isolates ultrasonic variations due to material microstructure. The use of this method can result in significant cost savings because the ultrasonic image can be interpreted correctly without the need for machining to achieve precise thickness uniformity during nondestructive evaluations of material development. The method is based on measurement of ultrasonic velocity. Images obtained using the thickness-independent methodology are compared with conventional velocity and c-scan echo peak amplitude images for monolithic ceramic (silicon nitride), metal matrix composite and polymer matrix composite materials. It was found that the thickness-independent ultrasonic images reveal and quantify correctly areas of global microstructural (pore and fiber volume fraction) variation due to the elimination of thickness effects. The thickness-independent ultrasonic imaging method described in this article is currently being commercialized under a cooperative agreement between NASA Lewis Research Center and Sonix, Inc.
4. Biomechanical analysis using FEA and experiments of a standard plate method versus three cable methods for fixing acetabular fractures with simultaneous THA.
PubMed
Aziz, Mina S R; Dessouki, Omar; Samiezadeh, Saeid; Bougherara, Habiba; Schemitsch, Emil H; Zdero, Radovan
2017-08-01
5. Robust scatter correction method for cone-beam CT using an interlacing-slit plate
Huang, Kui-Dong; Xu, Zhe; Zhang, Ding-Hua; Zhang, Hua; Shi, Wen-Long
2016-06-01
Cone-beam computed tomography (CBCT) has been widely used in medical imaging and industrial nondestructive testing, but the presence of scattered radiation will cause significant reduction of image quality. In this article, a robust scatter correction method for CBCT using an interlacing-slit plate (ISP) is carried out for convenient practice. Firstly, a Gaussian filtering method is proposed to compensate the missing data of the inner scatter image, and simultaneously avoid too-large values of calculated inner scatter and smooth the inner scatter field. Secondly, an interlacing-slit scan without detector gain correction is carried out to enhance the practicality and convenience of the scatter correction method. Finally, a denoising step for scatter-corrected projection images is added in the process flow to control the noise amplification The experimental results show that the improved method can not only make the scatter correction more robust and convenient, but also achieve a good quality of scatter-corrected slice images. Supported by National Science and Technology Major Project of the Ministry of Industry and Information Technology of China (2012ZX04007021), Aeronautical Science Fund of China (2014ZE53059), and Fundamental Research Funds for Central Universities of China (3102014KYJD022)
6. Methods and Piezoelectric Imbedded Sensors for Damage Detection in Composite Plates Under Ambient and Cryogenic Conditions
NASA Technical Reports Server (NTRS)
Engberg, Robert; Ooi, Teng K.
2004-01-01
New methods for structural health monitoring are being assessed, especially in high-performance, extreme environment, safety-critical applications. One such application is for composite cryogenic fuel tanks. The work presented here attempts to characterize and investigate the feasibility of using imbedded piezoelectric sensors to detect cracks and delaminations under cryogenic and ambient conditions. A variety of damage detection methods and different Sensors are employed in the different composite plate samples to aid in determining an optimal algorithm, sensor placement strategy, and type of imbedded sensor to use. Variations of frequency, impedance measurements, and pulse echoing techniques of the sensors are employed and compared. Statistical and analytic techniques are then used to determine which method is most desirable for a specific type of damage. These results are furthermore compared with previous work using externally mounted sensors. Results and optimized methods from this work can then be incorporated into a larger composite structure to validate and assess its structural health. This could prove to be important in the development and qualification of any 2" generation reusable launch vehicle using composites as a structural element.
7. Optimum stacking sequence design of laminated composite circular plates with curvilinear fibres by a layer-wise optimization method
Guenanou, A.; Houmat, A.
2018-05-01
The optimum stacking sequence design for the maximum fundamental frequency of symmetrically laminated composite circular plates with curvilinear fibres is investigated for the first time using a layer-wise optimization method. The design variables are two fibre orientation angles per layer. The fibre paths are constructed using the method of shifted paths. The first-order shear deformation plate theory and a curved square p-element are used to calculate the objective function. The blending function method is used to model accurately the geometry of the circular plate. The equations of motion are derived using Lagrange's method. The numerical results are validated by means of a convergence test and comparison with published values for symmetrically laminated composite circular plates with rectilinear fibres. The material parameters, boundary conditions, number of layers and thickness are shown to influence the optimum solutions to different extents. The results should serve as a benchmark for optimum stacking sequences of symmetrically laminated composite circular plates with curvilinear fibres.
8. Application of level set method to optimal vibration control of plate structures
Ansari, M.; Khajepour, A.; Esmailzadeh, E.
2013-02-01
Vibration control plays a crucial role in many structures, especially in the lightweight ones. One of the most commonly practiced method to suppress the undesirable vibration of structures is to attach patches of the constrained layer damping (CLD) onto the surface of the structure. In order to consider the weight efficiency of a structure, the best shapes and locations of the CLD patches should be determined to achieve the optimum vibration suppression with minimum usage of the CLD patches. This paper proposes a novel topology optimization technique that can determine the best shape and location of the applied CLD patches, simultaneously. Passive vibration control is formulated in the context of the level set method, which is a numerical technique to track shapes and locations concurrently. The optimal damping set could be found in a structure, in its fundamental vibration mode, such that the maximum modal loss factor of the system is achieved. Two different plate structures will be considered and the damping patches will be optimally located on them. At the same time, the best shapes of the damping patches will be determined too. In one example, the numerical results will be compared with those obtained from the experimental tests to validate the accuracy of the proposed method. This comparison reveals the effectiveness of the level set approach in finding the optimum shape and location of the CLD patches.
9. Multicycle Wilhelmy plate method for wetting properties, swelling and liquid sorption of wood.
PubMed
Moghaddam, Maziar Sedighi; Wålinder, Magnus E P; Claesson, Per M; Swerin, Agne
2013-10-01
A multicycle Wilhelmy plate method has been developed to investigate wetting properties, liquid sorption, and swelling of porous substrates such as wood. The use of the method is exemplified by studies of wood veneers of Scots pine sapwood and heartwood, which were subjected to repeated immersion and withdrawal in a swelling liquid (water) and in a nonswelling liquid (octane). The swelling liquid changes the sample dimensions during measurements, in particular its perimeter. This, in turn, influences the force registered. A model based on a linear combination of the measured force and final change in sample perimeter is suggested, and validated to elucidate the dynamic perimeter change of wood veneer samples. We show that pine heartwood and pine sapwood differ in several respects in their interaction with water. Pine heartwood showed (i) lower liquid uptake, (ii) lower swelling, (iii) higher contact angle, and (iv) lower level of dissolution of surface active components (extractives) than pine sapwood. We conclude that the method is also suitable for studying wetting properties of other porous and swellable materials. The wettability results were supported by surface chemical analysis using X-ray photoelectron spectroscopy, showing higher extractives and lignin content on heartwood than on sapwood surfaces.
10. The Surface-Tension Method of Visually Inspecting Honeycomb-Core Sandwich Plates
NASA Technical Reports Server (NTRS)
Katzoff, Samuel
1960-01-01
When one face of a metal-honeycomb-core sandwich plate is heated or cooled relative to the other, heat transfer through the core causes the temperature on each face at the lines of contact with the core to be slightly different from that on the rest of the face. If a thin liquid film is applied to the face, the variation of surface tension with temperature causes the liquid to move from warmer to cooler areas and thus to develop a pattern corresponding to the temperature pattern on the face. Irregularities in the pattern identify the locations where the core is not adequately bonded to the face sheet. The pattern is easily observed when a fluorescent liquid is used and illumination is by means of ultraviolet light. Observation in ordinary light is also possible when a very deeply colored liquid is used. A method based on the use of a thermographic phosphor to observe the temperature pattern was found to be less sensitive than the surface-tension method. A sublimation method was found to be not only less sensitive but also far more troublesome.
11. Methods for testing Zernike phase plates and a report on silicon-based phase plates with reduced charging and improved ageing characteristics
PubMed Central
Marko, Michael; Meng, Xing; Hsieh, Chyongere; Roussie, James; Striemer, Christopher
2013-01-01
Imaging with Zernike phase plates is increasingly being used in cryo-TEM tomography and cryo-EM single-particle applications. However, rapid ageing of the phase plates, together with the cost and effort in producing them, present serious obstacles to widespread adoption. We are experimenting with phase plates based on silicon chips that have thin windows; such phase plates could be mass-produced and made available at moderate cost. The windows are coated with conductive layers to reduce charging, and this considerably extends the useful life of the phase plates compared to traditional pure-carbon phase plates. However, a compromise must be reached between robustness and transmission through the phase-plate film. Details are given on testing phase-plate performance by means of imaging an amorphous thin film and evaluating the power spectra of the images. PMID:23994351
12. Push plate, mounting assembly, circuit board, and method of assembling thereof for ball grid array packages
SciTech Connect
Vaughn, Mark R.; Montague, Stephen
A push plate that includes springs in the form of cantilever flexures and an inspection window is disclosed. The push plate provides a known, uniform, down force and minimal torque to a package to be tested. The cantilevers have a known, calculable down force producing stiffness. The window provides for viewing of the package during testing.
13. A Novel Method for Characterizing the Impact Response of Functionally Graded Plates
DTIC Science & Technology
2008-09-01
Dennis [88], Ugural [125], Soedel [119], and Reddy [100] for complete 35 development of the theory from first principles. Only the equations and...Woinowsky-Krieger. Theory of Plates and Shells. McGraw-Hill Book Co., New York, NY, second edition, 1959. 125. Ugural , A. C. Stresses in Plates and
14. A statistical treatment of bioassay pour fractions
Barengoltz, Jack; Hughes, David
A bioassay is a method for estimating the number of bacterial spores on a spacecraft surface for the purpose of demonstrating compliance with planetary protection (PP) requirements (Ref. 1). The details of the process may be seen in the appropriate PP document (e.g., for NASA, Ref. 2). In general, the surface is mechanically sampled with a damp sterile swab or wipe. The completion of the process is colony formation in a growth medium in a plate (Petri dish); the colonies are counted. Consider a set of samples from randomly selected, known areas of one spacecraft surface, for simplicity. One may calculate the mean and standard deviation of the bioburden density, which is the ratio of counts to area sampled. The standard deviation represents an estimate of the variation from place to place of the true bioburden density commingled with the precision of the individual sample counts. The accuracy of individual sample results depends on the equipment used, the collection method, and the culturing method. One aspect that greatly influences the result is the pour fraction, which is the quantity of fluid added to the plates divided by the total fluid used in extracting spores from the sampling equipment. In an analysis of a single sample’s counts due to the pour fraction, one seeks to answer the question: What is the probability that if a certain number of spores are counted with a known pour fraction, that there are an additional number of spores in the part of the rinse not poured. This is given for specific values by the binomial distribution density, where detection (of culturable spores) is success and the probability of success is the pour fraction. A special summation over the binomial distribution, equivalent to adding for all possible values of the true total number of spores, is performed. This distribution when normalized will almost yield the desired quantity. It is the probability that the additional number of spores does not exceed a certain value. Of course
15. Differential specificity of selective culture media for enumeration of pathogenic vibrios: advantages and limitations of multi-plating methods.
PubMed
Nigro, Olivia D; Steward, Grieg F
2015-04-01
Plating environmental samples on vibrio-selective chromogenic media is a commonly used technique that allows one to quickly estimate concentrations of putative vibrio pathogens or to isolate them for further study. Although this approach is convenient, its usefulness depends directly on how well the procedure selects against false positives. We tested whether a chromogenic medium, CHROMagar Vibrio (CaV), used alone (single-plating) or in combination (double-plating) with a traditional medium thiosulfate-citrate-bile-salts (TCBS), could improve the discrimination among three pathogenic vibrio species (Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus) and thereby decrease the number of false-positive colonies that must be screened by molecular methods. Assays were conducted on water samples from two estuarine environments (one subtropical, one tropical) in a variety of seasonal conditions. The results of the double-plating method were confirmed by PCR and 16S rRNA sequencing. Our data indicate that there is no significant difference in the false-positive rate between CaV and TCBS when using a single-plating technique, but determining color changes on the two media sequentially (double-plating) reduced the rate of false positive identification in most cases. The improvement achieved was about two-fold on average, but varied greatly (from 0- to 5-fold) and depended on the sampling time and location. The double-plating method was most effective for V. vulnificus in warm months, when overall V. vulnificus abundance is high (false positive rates as low as 2%, n=178). Similar results were obtained for V. cholerae (minimum false positive rate of 16%, n=146). In contrast, the false positive rate for V. parahaemolyticus was always high (minimum of 59%, n=109). Sequence analysis of false-positive isolates indicated that the majority of confounding isolates are from the Vibrionaceae family, however, members of distantly related bacterial groups were also able to
16. Immobilization methods for the rapid total chemical synthesis of proteins on microtiter plates.
PubMed
Zitterbart, Robert; Krumrey, Michael; Seitz, Oliver
2017-07-01
The chemical synthesis of proteins typically involves the solid-phase peptide synthesis of unprotected peptide fragments that are stitched together in solution by native chemical ligation (NCL). The process is slow, and throughput is limited because of the need for repeated high performance liquid chromatography purification steps after both solid-phase peptide synthesis and NCL. With an aim to provide faster access to functional proteins and to accelerate the functional analysis of synthetic proteins by parallelization, we developed a method for the high performance liquid chromatography-free synthesis of proteins on the surface of microtiter plates. The method relies on solid-phase synthesis of unprotected peptide fragments, immobilization of the C-terminal fragment and on-surface NCL with an unprotected peptide thioester in crude form. Herein, we describe the development of a suitable immobilization chemistry. We compared (i) formation of nickel(II)-oligohistidine complexes, (ii) Cu-based [2 + 3] alkine-azide cycloaddition and (iii) hydrazone ligation. The comparative study identified the hydrazone ligation as most suitable. The sequence of immobilization via hydrazone ligation, on-surface NCL and radical desulfurization furnished the targeted SH3 domains in near quantitative yield. The synthetic proteins were functional as demonstrated by an on-surface fluorescence-based saturation binding analysis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.
17. NDE methods for determining the materials properties of silicon carbide plates
Kenderian, Shant; Kim, Yong; Johnson, Eric; Palusinski, Iwona A.
2009-08-01
Two types of SiC plates, differing in their manufacturing processes, were interrogated using a variety of NDE techniques. The task of evaluating the materials properties of these plates was a challenge due to their non-uniform thickness. Ultrasound was used to estimate the Young's Modulus and calculate the thickness profile and Poisson's Ratio of the plates. The Young's Modulus profile plots were consistent with the thickness profile plots, indicating that the technique was highly influenced by the non-uniform thickness of the plates. The Poisson's Ratio is calculated from the longitudinal and shear wave velocities. Because the thickness is cancelled out, the result is dependent only on the time of flight of the two wave modes, which can be measured accurately. X-Ray was used to determine if any density variations were present in the plates. None were detected suggesting that the varying time of flight of the acoustic wave is attributed only to variations in the elastic constants and thickness profiles of the plates. Eddy Current was used to plot the conductivity profile. Surprisingly, the conductivity profile of one type of plates varied over a wide range rarely seen in other materials. The other type revealed a uniform conductivity profile.
18. A robust method of thin plate spline and its application to DEM construction
Chen, Chuanfa; Li, Yanyan
2012-11-01
In order to avoid the ill-conditioning problem of thin plate spline (TPS), the orthogonal least squares (OLS) method was introduced, and a modified OLS (MOLS) was developed. The MOLS of TPS (TPS-M) can not only select significant points, termed knots, from large and dense sampling data sets, but also easily compute the weights of the knots in terms of back-substitution. For interpolating large sampling points, we developed a local TPS-M, where some neighbor sampling points around the point being estimated are selected for computation. Numerical tests indicate that irrespective of sampling noise level, the average performance of TPS-M can advantage with smoothing TPS. Under the same simulation accuracy, the computational time of TPS-M decreases with the increase of the number of sampling points. The smooth fitting results on lidar-derived noise data indicate that TPS-M has an obvious smoothing effect, which is on par with smoothing TPS. The example of constructing a series of large scale DEMs, located in Shandong province, China, was employed to comparatively analyze the estimation accuracies of the two versions of TPS and the classical interpolation methods including inverse distance weighting (IDW), ordinary kriging (OK) and universal kriging with the second-order drift function (UK). Results show that regardless of sampling interval and spatial resolution, TPS-M is more accurate than the classical interpolation methods, except for the smoothing TPS at the finest sampling interval of 20 m, and the two versions of kriging at the spatial resolution of 15 m. In conclusion, TPS-M, which avoids the ill-conditioning problem, is considered as a robust method for DEM construction.
19. A Simple Method for Closure of Urethrocutaneous Fistula after Tubularized Incised Plate Repair: Preliminary Results.
PubMed
2016-11-01
Urethrocutaneous fistula (UCF) is the most prevalent complication after hypospadias repair surgery. Many methods have been developed for UCF correction, and the best technique for UCF repair is determined based on the size, location, and number of fistulas, as well as the status of the surrounding skin. In this study, we introduced and evaluated a simple method for UCF correction after tubularized incised plate (TIP) repair. This clinical study was conducted on children with UCFs ≤ 4 mm that developed after TIP surgery for hypospadias repair. The skin was incised around the fistula and the tract was released from the surrounding tissues and the dartos fascia, then ligated with 5 - 0 polydioxanone (PDS) sutures. The dartos fascia, as the second layer, was covered on the fistula tract with PDS thread (gauge 5 - 0) by the continuous suture method. The skin was closed with 6 - 0 Vicryl sutures. After six months of follow-up, surgical outcomes were evaluated based on fistula relapse and other complications. After six months, relapse occurred in only one patient, a six-year-old boy with a single 4-mm distal opening, who had undergone no previous fistula repairs. Therefore, in 97.5% of the cases, relapse was non-existent. Other complications, such as urethral stenosis, intraurethral obstruction, and epidermal inclusion cysts, were not seen in the other patients during the six-month follow-up period. This repair method, which is simple, rapid, and easily learned, is highly applicable, with a high success rate for the closure of UCFs measuring up to 4 mm in any location.
20. The construction of airfoil pressure models by the plate method: Achievements, current research, technology development and potential applications
NASA Technical Reports Server (NTRS)
Lawing, P. L.
1985-01-01
A method of constructing airfoils by inscribing pressure channels on the face of opposing plates, bonding them together to form one plate with integral channels, and contour machining this plate to form an airfoil model is described. The research and development program to develop the bonding technology is described as well as the construction and testing of an airfoil model. Sample aerodynamic data sets are presented and discussed. Also, work currently under way to produce thin airfoils with camber is presented. Samples of the aft section of a 6 percent airfoil with complete pressure instrumentation including the trailing edge are pictured and described. This technique is particularly useful in fabricating models for transonic cryogenic testing, but it should find application in a wide ange of model construction projects, as well as the fabrication of fuel injectors, space hardware, and other applications requiring advanced bonding technology and intricate fluid passages.
1. Damping of composite plate for space structures: Prediction and measurement methods
Marchetti, M.; Morganti, F.; Mucciante, L.; Bruno, C.
Composite materials are extensively used for space structures: the sandwich and laminate panels are now part of the current manufacturing technology for spacecraft and antenna reflectors. Depending on the applications, some mechanical parameters are considered driving in the design, in order to satisfy the required structural performance. Among them, the knowledge of the damping is necessary to evaluate the dynamic behaviour of the structures. That particularly applies to the composite structures for space applications; for which an optimization of their mass versus their stiffness is attempted to take into account both launch and on station environments. The prediction of the damping factors of composites is rather difficult since it depends not only on the nature of the materials, which are in general neither homogeneous nor isotropic, but also on the kind of structures (i.e. size and shape) and on the manufacturing methodology, due to the strong non-linearity in the material behaviour. All the above is also impacted by the tendency of these materials to microcracking under stress. This phenomenon, mainly correlated to the cyclic loads introduced by thermal ageing, produces a variation of damping with time. For these reasons an evaluation of the damping characteristics of this kind of structure has been generally obtained by tests on full scale hardware or specimens with suitable dimension, being any prediction method rather difficult to apply. The purpose of this work is to study the damping behaviour of Gr/Ep, Kevlar/Ep and Glass Fiber/Ep composites which are extensively used in space structures, starting from test results on beam and plate shaped specimens. Experimental evidence will be fitted in an analytical and numerical study, the purpose of which is to correlate the energy dissipated in the composite to the lamination typology. Using a Finite Element Method, the amount of energy dissipated for each mode will be also evaluated, providing the correlations
2. Comparison of polymerase chain reaction methods and plating for analysis of enriched cultures of Listeria monocytogenes when using the ISO11290-1 method.
PubMed
Dalmasso, Marion; Bolocan, Andrei Sorin; Hernandez, Marta; Kapetanakou, Anastasia E; Kuchta, Tomáš; Manios, Stavros G; Melero, Beatriz; Minarovičová, Jana; Muhterem, Meryem; Nicolau, Anca Ioana; Rovira, Jordi; Skandamis, Panagiotis N; Stessl, Beatrix; Wagner, Martin; Jordan, Kieran; Rodríguez-Lázaro, David
2014-03-01
Analysis for Listeria monocytogenes by ISO11290-1 is time-consuming, entailing two enrichment steps and subsequent plating on agar plates, taking five days without isolate confirmation. The aim of this study was to determine if a polymerase chain reaction (PCR) assay could be used for analysis of the first and second enrichment broths, saving four or two days, respectively. In a comprehensive approach involving six European laboratories, PCR and traditional plating of both enrichment broths from the ISO11290-1 method were compared for the detection of L. monocytogenes in 872 food, raw material and processing environment samples from 13 different dairy and meat food chains. After the first and second enrichments, total DNA was extracted from the enriched cultures and analysed for the presence of L. monocytogenes DNA by PCR. DNA extraction by chaotropic solid-phase extraction (spin column-based silica) combined with real-time PCR (RTi-PCR) was required as it was shown that crude DNA extraction applying sonication lysis and boiling followed by traditional gel-based PCR resulted in fewer positive results than plating. The RTi-PCR results were compared to plating, as defined by the ISO11290-1 method. For first and second enrichments, 90% of the samples gave the same results by RTi-PCR and plating, whatever the RTi-PCR method used. For the samples that gave different results, plating was significantly more accurate for detection of positive samples than RTi-PCR from the first enrichment, but RTi-PCR detected a greater number of positive samples than plating from the second enrichment, regardless of the RTi-PCR method used. RTi-PCR was more accurate for non-food contact surface and food contact surface samples than for food and raw material samples especially from the first enrichment, probably because of sample matrix interference. Even though RTi-PCR analysis of the first enrichment showed less positive results than plating, in outbreak scenarios where a rapid result is
3. Bacteriocidal activity of sanitizers against Enterococcus faecium attached to stainless steel as determined by plate count and impedance methods.
PubMed
Andrade, N J; Bridgeman, T A; Zottola, E A
1998-07-01
Enterococcus faecium attached to stainless steel chips (100 mm2) was treated with the following sanitizers: sodium hypochlorite, peracetic acid (PA), peracetic acid plus an organic acid (PAS), quaternary ammonium, organic acid, and anionic acid. The effectiveness of sanitizer solutions on planktonic cells (not attached) was evaluated by the Association of Official Analytical Chemists (AOAC) suspension test. The number of attached cells was determined by impedance measurement and plate count method after vortexing. The decimal reduction (DR) in numbers of the E. faecium population was determined for the three methods and was analyzed by analysis of variance (P < 0.05) using Statview software. The adhered cells were more resistant (P < 0.05) than nonadherent cells. The DR averages for all of the sanitizers for 30 s of exposure were 6.4, 2.2, and 2.5 for the AOAC suspension test, plate count method after vortexing, and impedance measurement, respectively. Plate count and impedance methods showed a difference (P < 0.05) after 30 s of sanitizer exposure but not after 2 min. The impedance measurement was the best method to measure adherent cells. Impedance measurement required the development of a quadratic regression. The equation developed from 82 samples is as follows: log CFU/chip = 0.2385T2-0.96T + 9.35, r2 = 0.92, P < 0.05, T = impedance detection time in hours. This method showed that the sanitizers PAS and PA were more effective against E. faecium than the other sanitizers. At 30 s, the impedance method recovered about 25 times more cells than the plate count method after vortexing. These data suggest that impedance measurement is the method of choice when evaluating the number of bacterial cells adhered to a surface.
4. A high-throughput microtiter plate based method for the determination of peracetic acid and hydrogen peroxide.
PubMed
Putt, Karson S; Pugh, Randall B
2013-01-01
Peracetic acid is gaining usage in numerous industries who have found a myriad of uses for its antimicrobial activity. However, rapid high throughput quantitation methods for peracetic acid and hydrogen peroxide are lacking. Herein, we describe the development of a high-throughput microtiter plate based assay based upon the well known and trusted titration chemical reactions. The adaptation of these titration chemistries to rapid plate based absorbance methods for the sequential determination of hydrogen peroxide specifically and the total amount of peroxides present in solution are described. The results of these methods were compared to those of a standard titration and found to be in good agreement. Additionally, the utility of the developed method is demonstrated through the generation of degradation curves of both peracetic acid and hydrogen peroxide in a mixed solution.
5. A High-Throughput Microtiter Plate Based Method for the Determination of Peracetic Acid and Hydrogen Peroxide
PubMed Central
Putt, Karson S.; Pugh, Randall B.
2013-01-01
Peracetic acid is gaining usage in numerous industries who have found a myriad of uses for its antimicrobial activity. However, rapid high throughput quantitation methods for peracetic acid and hydrogen peroxide are lacking. Herein, we describe the development of a high-throughput microtiter plate based assay based upon the well known and trusted titration chemical reactions. The adaptation of these titration chemistries to rapid plate based absorbance methods for the sequential determination of hydrogen peroxide specifically and the total amount of peroxides present in solution are described. The results of these methods were compared to those of a standard titration and found to be in good agreement. Additionally, the utility of the developed method is demonstrated through the generation of degradation curves of both peracetic acid and hydrogen peroxide in a mixed solution. PMID:24260173
6. Estimation of Stress Concentration Factor of Plate with Hole using Piezoelectric Actuator and Finite Element Method
Abuzaid, A.; Hrairi, M.; Shaik Dawood, M. S. I.
2017-03-01
In this paper, the effect of piezoelectric actuators placed above a circular hole of a rectangular plate subjected to uniform uniaxial tension is studied. The core idea is to investigate the stress (compression/tension) produced by the piezoelectric actuators on the stress distribution around the hole and along the width of the host plate. For this purpose, Finite Element Analysis (FEA) was carried out through parametric study in ANSYS software. The results demonstrated that the positive electric field would decrease and change the state of the stress distribution along the width of the host plate in contrast to the negative applied electric filed which increases the stress distribution smoothly without affecting its behaviour. The results also indicated that the reduction of the stress concentration factor increases with the decrease of the ratio (D/W) for the same applied positive electric field.
7. The Lagrangian Multiplier Method of Finding Upper and Lower Limits to Critical Stresses of Clamped Plates
DTIC Science & Technology
1946-01-01
geometrica ~ boundary condi- tions of the problem. (2) The energy of the load-plate system is computed for this deflection surface and is then minimized...and interpolating to find the k that makes the seriw vanish. The correct value of m is that which gives the lowest value of k. For two half waves (m=2...the square plate, the present rekdively simple upper- and lower-limit calcula- tions show that his est,imatd limit of error is correct for this case
8. A new diagnostic method for separating airborne and structureborne noise radiated by plates with applications for propeller driven aircraft
NASA Technical Reports Server (NTRS)
Mcgary, Michael C.
1988-01-01
The anticipated application of advanced turboprop propulsion systems is expected to increase the interior noise of future aircraft to unacceptably high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a prime obstacle in the development of efficient noise control treatments for propeller-driven aircraft. A new diagnostic method that permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on an aluminum plate. The results of the study indicate that the proposed method could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available.
9. Evaluation of the methods for enumerating coliform bacteria from water samples using precise reference standards.
PubMed
Wohlsen, T; Bates, J; Vesey, G; Robinson, W A; Katouli, M
2006-04-01
To use BioBall cultures as a precise reference standard to evaluate methods for enumeration of Escherichia coli and other coliform bacteria in water samples. Eight methods were evaluated including membrane filtration, standard plate count (pour and spread plate methods), defined substrate technology methods (Colilert and Colisure), the most probable number method and the Petrifilm disposable plate method. Escherichia coli and Enterobacter aerogenes BioBall cultures containing 30 organisms each were used. All tests were performed using 10 replicates. The mean recovery of both bacteria varied with the different methods employed. The best and most consistent results were obtained with Petrifilm and the pour plate method. Other methods either yielded a low recovery or showed significantly high variability between replicates. The BioBall is a very suitable quality control tool for evaluating the efficiency of methods for bacterial enumeration in water samples.
10. Requirements and testing methods for surfaces of metallic bipolar plates for low-temperature PEM fuel cells
Jendras, P.; Lötsch, K.; von Unwerth, T.
2017-03-01
To reduce emissions and to substitute combustion engines automotive manufacturers, legislature and first users aspire hydrogen fuel cell vehicles. Up to now the focus of research was set on ensuring functionality and increasing durability of fuel cell components. Therefore, expensive materials were used. Contemporary research and development try to substitute these substances by more cost-effective material combinations. The bipolar plate is a key component with the greatest influence on volume and mass of a fuel cell stack and they have to meet complex requirements. They support bending sensitive components of stack, spread reactants over active cell area and form the electrical contact to another cell. Furthermore, bipolar plates dissipate heat of reaction and separate one cell gastight from the other. Consequently, they need a low interfacial contact resistance (ICR) to the gas diffusion layer, high flexural strength, good thermal conductivity and a high durability. To reduce costs stainless steel is a favoured material for bipolar plates in automotive applications. Steel is characterized by good electrical and thermal conductivity but the acid environment requires a high chemical durability against corrosion as well. On the one hand formation of a passivating oxide layer increasing ICR should be inhibited. On the other hand pitting corrosion leading to increased permeation rate may not occur. Therefore, a suitable substrate lamination combination is wanted. In this study material testing methods for bipolar plates are considered.
11. Static analysis of the hull plate using the finite element method
Ion, A.
2015-11-01
This paper aims at presenting the static analysis for two levels of a container ship's construction as follows: the first level is at the girder / hull plate and the second level is conducted at the entire strength hull of the vessel. This article will describe the work for the static analysis of a hull plate. We shall use the software package ANSYS Mechanical 14.5. The program is run on a computer with four Intel Xeon X5260 CPU processors at 3.33 GHz, 32 GB memory installed. In terms of software, the shared memory parallel version of ANSYS refers to running ANSYS across multiple cores on a SMP system. The distributed memory parallel version of ANSYS (Distributed ANSYS) refers to running ANSYS across multiple processors on SMP systems or DMP systems.
12. An equilibrium method for prediction of transverse shear stresses in a thick laminated plate
NASA Technical Reports Server (NTRS)
Chaudhuri, R. Z.
1986-01-01
First two equations of equilibrium are utilized to compute the transverse shear stress variation through thickness of a thick laminated plate after in-plane stresses have been computed using an assumed quadratic displacement triangular element based on transverse inextensibility and layerwise constant shear angle theory (LCST). Centroid of the triangle is the point of exceptional accuracy for transverse shear stresses. Numerical results indicate close agreement with elasticity theory. An interesting comparison between the present theory and that based on assumed stress hybrid finite element approach suggests that the latter does not satisfy the condition of free normal traction at the edge. Comparison with numerical results obtained by using constant shear angle theory suggests that LCST is close to the elasticity solution while the CST is closer to classical (CLT) solution. It is also demonstrated that the reduced integration gives faster convergence when the present theory is applied to a thin plate.
13. Spiral Plating Method To Quantify the Six Major Non-O157 Escherichia coli Serogroups in Cattle Feces.
PubMed
Shridhar, Pragathi B; Noll, Lance W; Cull, Charley A; Shi, Xiaorong; Cernicchiaro, Natalia; Renter, David G; Bai, Jianfa; Nagaraja, T G
2017-04-17
Cattle are a major reservoir of the six major Shiga toxin-producing non-O157 Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145) responsible for foodborne illnesses in humans. Besides prevalence in feces, the concentrations of STEC in cattle feces play a major role in their transmission dynamics. A subset of cattle, referred to as super shedders, shed E. coli O157 at high concentrations (≥4 log CFU/g of feces). It is not known whether a similar pattern of fecal shedding exists for non-O157. Our objectives were to initially validate the spiral plating method to quantify the six non-O157 E. coli serogroups with pure cultures and culture-spiked fecal samples and then determine the applicability of the method and compare it with multiplex quantitative PCR (mqPCR) assays for the quantification of the six non-O157 E. coli serogroups in cattle fecal samples collected from commercial feedlots. Quantification limits of the spiral plating method were 3 log, 3 to 4 log, and 3 to 5 log CFU/mL or CFU/g for individual cultures, pooled pure cultures, and cattle fecal samples spiked with pooled pure cultures, respectively. Of the 1,152 cattle fecal samples tested from eight commercial feedlots, 122 (10.6%) and 320 (27.8%) harbored concentrations ≥4 log CFU/g of one or more of the six serogroups of non-O157 by spiral plating and mqPCR methods, respectively. A majority of quantifiable samples, detected by either spiral plating (135 of 137, 98.5%) or mqPCR (239 of 320, 74.7%), were shedding only one serogroup. Only one of the quantifiable samples was positive for a serogroup carrying Shiga toxin (stx 1 ) and intimin (eae) genes; 38 samples were positive for serogroups carrying the intimin gene. In conclusion, the spiral plating method can be used to quantify non-O157 serogroups in cattle feces, and our study identified a subset of cattle that was super shedders of non-O157 E. coli . The method has the advantage of quantifying non-O157 STEC, unlike mqPCR that
14. A fictitious domain method for fluid/solid interaction applied to the plate folding over the 660 Km depth boundary.
Cerpa, Nestor; Hassani, Riad; Gerbault, Muriel
2014-05-01
A large variety of geodynamical problems involve a mechanical system where a competent body is embedded in a more deformable medium, and hence they can be viewed as belonging to the field of solid/fluid interaction.The lithosphere/asthenosphere interaction in subduction zones is among those kind of problems which are generally difficult to tackle numerically since the immersed (solid) body can be geometrically complex and the surrounding (fluid) medium can thus undergo large deformation. Our work presents a new numerical approach for the study of subduction zones. The lithosphere is modeled as a Maxwell viscoelastic body sinking in the viscous asthenosphere. Both domains are discretized by the Finite Element Method (FEM) and we use a staggered coupling method. The interaction is provided by a non-matching interface method called the Fictitious Domain Method (FDM). We have validated this method with some 2-D benchmarks and examples. Through this numerical coupling method we aim at studying the effect of mantle viscosity on the cyclicity of slab folding on the 660 km depth discontinuity approximated as an impenetrable barrier. Depending on the kinematics condition imposed to the overriding and subducting plates, analog and numerical models have previously shown that cyclicity occurs. The viscosity of the asthenosphere (taken as an isoviscous or a double viscosity-layer fluid) impacts on folding cyclicity and consequently on the slab's dip as well as the stress regime of the overriding plate. In particular, applying far-field plate velocities corresponding to those of the South-American and Nazca plates at present, (4.3 cm/yr and 2.9 cm/yr respectively), we obtain periodic slab folding which is consistent with magmatism and sedimentalogical records. These data report cycles in orogenic growth of the order of 30-40 Myrs, a period that we reproduce when the mantle viscosity ranges in between 3 and 5 x 1020 Pa.s. Moreover, we reproduce episodic development of horizontal
15. An alternative method in mandibular fracture treatment: bone graft use instead of a plate.
PubMed
Alagöz, Murat Sahin; Uysal, Ahmet Cagri; Sensoz, Omer
2008-03-01
In the treatment of the mandibular fractures, one of the main principles is to use the least amount of foreign material. We present an alternative technique that the bone grafts harvested from the fracture borders or from the iliac crest were used instead of plates and the fixation was done with screws. In the study including 24 mandible fractures, the bone grafts harvested from the fracture borders were used in the 10 favorable fractures and the bone grafts harvested from the iliac crest were used in the 14 unfavorable fractures. In the combined mandible fractures, four fractures were fixated with titanium plates and the other side with the bone graft. The patients, who were followed up for 12 to 20 months, were evaluated with macroscopic occlusion, panoramic graphs, and three-dimensional computerized tomographs. The advantage of this technique of fixation with the autogenous tissue is reduced infection rates and reduced operation costs. In the pediatric patients, the second session operation of plate removal is not necessary.
16. A correlation method to predict the surface pressure distribution on an infinite plate from which a jet is issuing. [effects of a lifting jet
NASA Technical Reports Server (NTRS)
Perkins, S. C., Jr.; Menhall, M. R.
1978-01-01
A correlation method to predict pressures induced on an infinite plate by a jet issuing from the plate into a subsonic free stream was developed. The complete method consists of an analytical method which models the blockage and entrainment properties of the jet and a correlation which accounts for the effects of separation. The method was developed for jet velocity ratios up to ten and for radial distances up to five diameters from the jet. Correlation curves and data comparisons are presented for jets issuing normally from a flat plate with velocity ratios one to twelve. Also, a list of references which deal with jets in a crossflow is presented.
17. An optimal open/closed-loop control method with application to a pre-stressed thin duralumin plate
The excessive vibrations of a pre-stressed duralumin plate, suppressed by a combination of open-loop and closed-loop controls, also known as open/closed-loop control, is studied in this thesis. The two primary steps involved in this process are: Step (I) with an assumption that the closed-loop control law is proportional, obtain the optimal open-loop control by direct minimization of the performance measure consisting of energy at terminal time and a penalty on open-loop control force via calculus of variations. If the performance measure also involves a penalty on closed-loop control effort then a Fourier based method is utilized. Step (II) the energy at terminal time is minimized numerically to obtain optimal values of feedback gains. The optimal closed-loop control gains obtained are used to describe the displacement and the velocity of open-loop, closed-loop and open/closed-loop controlled duralumin plate.
18. A direct plating method for estimating populations of Escherichia coli O157 in bovine manure and manure-based materials.
PubMed
Berry, Elaine D; Wells, James E
2008-11-01
Escherichia coli O157:H7 outbreaks associated with produce consumption have brought attention to livestock manures and manure-based soil amendments as potential sources of pathogens for the contamination of these crops. Procedures for enumeration of E. coli O157:H7 are needed to assess the risks of transmission from these manures and their by-products. A direct plating method employing spiral plating onto CHROMagar O157 was investigated for enumeration of E. coli O157:H7 in feedlot surface material, aged bovine manure, bovine manure compost, and manure-amended soil. In studies utilizing samples spiked with a five-strain cocktail of E. coli O157:H7 at levels ranging from 102 to 10(5) CFU/g of sample, there were strong correlations between the observed and predicted levels of this pathogen. Although the addition of 2.5 mg/liter potassium tellurite and 5 mg/liter novobiocin made the medium more restrictive, these amendments enhanced the ability to identify and enumerate E. coli O157:H7 in feedlot surface material, which contained a higher proportion of fresh feces than did the other three sample types and therefore higher levels of interfering bacterial microflora. The spiral plating method was further assessed to determine its ability to enumerate E. coli O157:H7 in naturally contaminated feedlot surface material. Comparison of E. coli O157:H7 counts in feedlot surface material obtained by the spiral plating method and a most probable number technique were well correlated. We conclude that direct spiral plating onto CHROMagar O157 is effective for estimating E. coli O157:H7 levels in a variety of manures and manure-containing sample types to a lower detection limit of 200 CFU/g. The method has application for determining E. coli O157:H7 concentrations in manures and composts before their sale and use as soil amendments and for measuring the effectiveness of manure treatment processes to reduce or inactivate this pathogen.
19. A novel combined method of osteosynthesis in treatment of tibial fractures: a comparative study on sheep with application of rod-through-plate fixator and bone plating.
PubMed
Tralman, G; Andrianov, V; Arend, A; Männik, P; Kibur, R T; Nõupuu, K; Uksov, D; Aunapuu, M
2013-04-01
The study compares the efficiency of a new bone fixator combining periostal and intramedullary osteosynthesis to bone plating in treatment of tibial fractures in sheep. Experimental osteotomies were performed in the middle third of the left tibia. Animals were divided into two groups: in one group (four animals) combined osteosynthesis (rod-through-plate fixator, RTP fixator) was applied, and in the other group (three animals) bone plating was used. The experiments lasted for 10 weeks during which fracture union was followed by radiography, and the healing process was studied by blood serum markers reflecting bone turnover and by histological and immunohistochemical investigations. In the RTP fixator group, animals started to load body weight on the operated limbs the next day after the surgery, while in the bone plating group, this happened only on the seventh day. In the RTP fixator group, consolidation of fractures was also faster, as demonstrated by radiographical, histological, and immunohistochemical investigations and in part by blood serum markers for bone formation. It can be concluded that application of RTP fixation is more efficient than plate fixation in the treatment of experimental osteotomies of long bones in sheep. © 2012 Blackwell Verlag GmbH.
20. Comparison of methods for isolation and enumeration of thermophilic actinomycetes from dust.
PubMed Central
Treuhaft, M W; Arden Jones, M P
1982-01-01
Thermophilic actinomycetes are the primary sensitizing agents in farmer's lung disease. We compared dilution pour-plate and spread-plate methods for their usefulness in enumerating thermophilic actinomycetes in moldy silage dust and evaluated the ability of a nonquantitative gravity settling technique to recover thermophilic actinomycetes from moldy silage. Spread plates and pour plates yielded similar estimates of total thermophiles. Higher counts were observed on spread plates (P less than 0.05) for Thermoactinomyces candidus, Micropolyspora faeni, and Saccharomonospora viridis. M. faeni and S. viridis were less efficient than T. candidus in breaking through the agar of pour plates to form colonies which could be identified. Coefficients of variability were less than 10% for the two methods. The relative proportion of organisms recovered by the settling method correlated well with that recovered on spread plates for M. faeni (r = 0.79), S. viridis (r = 0.88), and Thermomonospora spp. (r = 0.79), but not well for T. candidus (r = 0.28). When sophisticated air-sampling equipment is not available, dilution spread plates of dust washings provide a reproducible method for enumerating a broad range of thermophilic actinomycetes of interest. The gravity settling method is a simple, rapid alternative when isolation is all that is required. PMID:6761363
1. Volume holographic elements in Kodak 131 plates processed with SHSG method
Collados, Manuel V.; Atencia, Jesus; Lopez, Ana M.; Quintanilla, Manuel M.
2001-08-01
A SHSG procedure to register volume phase holograms in Kodak 131 plates is presented. We analyze the influence on the diffraction efficiency of the developing step and the temperature of the bleaching bath of usual SHSG processes. Applying a simple 12 steps process to form phase transmission holograms developing with D-19, bleaching with R-10 at 70 degrees C and removing the sensitizing dyes that remain in the emulsion with a diluted methanol bath after the fixation step, we obtain relative efficiencies of 100 percent and effective efficiencies of 70 percent.
2. Semi-analytical discontinuous Galerkin finite element method for the calculation of dispersion properties of guided waves in plates.
PubMed
Hebaz, Salah-Eddine; Benmeddour, Farouk; Moulin, Emmanuel; Assaad, Jamal
2018-01-01
The development of reliable guided waves inspection systems is conditioned by an accurate knowledge of their dispersive properties. The semi-analytical finite element method has been proven to be very practical for modeling wave propagation in arbitrary cross-section waveguides. However, when it comes to computations on complex geometries to a given accuracy, it still has a major drawback: the high consumption of resources. Recently, discontinuous Galerkin finite element method (DG-FEM) has been found advantageous over the standard finite element method when applied as well in the frequency domain. In this work, a high-order method for the computation of Lamb mode characteristics in plates is proposed. The problem is discretised using a class of DG-FEM, namely, the interior penalty methods family. The analytical validation is performed through the homogeneous isotropic case with traction-free boundary conditions. Afterwards, functionally graded material plates are analysed and a numerical example is presented. It was found that the obtained results are in good agreement with those found in the literature.
3. Mean grain size detection of DP590 steel plate using a corrected method with electromagnetic acoustic resonance.
PubMed
Wang, Bin; Wang, Xiaokai; Hua, Lin; Li, Juanjuan; Xiang, Qing
2017-04-01
Electromagnetic acoustic resonance (EMAR) is a considerable method to determine the mean grain size of the metal material with a high precision. The basic ultrasonic attenuation theory used for the mean grain size detection of EMAR is come from the single phase theory. In this paper, the EMAR testing was carried out based on the ultrasonic attenuation theory. The detection results show that the double peaks phenomenon occurs in the EMAR testing of DP590 steel plate. The dual phase structure of DP590 steel is the inducement of the double peaks phenomenon in the EMAR testing. In reaction to the phenomenon, a corrected method with EMAR was put forward to detect the mean grain size of dual phase steel. Compared with the traditional attenuation evaluation method and the uncorrected method with EMAR, the corrected method with EMAR shows great effectiveness and superiority for the mean grain size detection of DP590 steel plate. Copyright © 2016. Published by Elsevier B.V.
4. An ultrasonic method for determination of elastic moduli, density, attenuation and thickness of a polymer coating on a stiff plate.
PubMed
Lavrentyev, A I; Rokhlin, S I
2001-04-01
An ultrasonic method proposed by us for determination of the complete set of acoustical and geometrical properties of a thin isotropic layer between semispaces (J. Acoust. Soc. Am. 102 (1997) 3467) is extended to determination of the properties of a coating on a thin plate. The method allows simultaneous determination of the coating thickness, density, elastic moduli and attenuation (longitudinal and shear) from normal and oblique incidence reflection (transmission) frequency spectra. Reflection (transmission) from the coated plate is represented as a function of six nondimensional parameters of the coating which are determined from two experimentally measured spectra: one at normal and one at oblique incidence. The introduction of the set of nondimensional parameters allows one to transform the reconstruction process from one search in a six-dimensional space to two searches in three-dimensional spaces (one search for normal incidence and one for oblique). Thickness, density, and longitudinal and shear elastic moduli of the coating are calculated from the nondimensional parameters determined. The sensitivity of the method to individual properties and its stability against experimental noise are studied and the inversion algorithm is accordingly optimized. An example of the method and experimental measurement for comparison is given for a polypropylene coating on a steel foil.
5. An Evaluation Method for the Suppression of Pathogenic Fusarium oxysporum by Soil Microorganisms Using the Dilution Plate Technique.
PubMed
Mitsuboshi, Masahiro; Kioka, Yuuzou; Noguchi, Katsunori; Asakawa, Susumu
2016-09-29
Soil-borne diseases caused by pathogenic microorganisms are one of the main factors responsible for the decline in crop yields in farmlands. Pathogenic Fusarium oxysporum causes serious damage to various crops, and, thus, a feasible diagnostic method for soil-borne diseases is required. We herein examined a simple method to evaluate the suppressiveness of soil microorganisms against a pathogen by co-cultivating indigenous soil microorganisms and a pathogenic fungus (F. oxysporum f. sp. spinaciae). We inoculated F. oxysporum onto the center of agar medium plates mixed with a dilution series of a suspension of organic fertilizers or soil. After an approximately one-week cultivation, the growth degree of F. oxysporum was estimated based on the size of the colonies that formed on the plates. The growth degree of F. oxysporum significantly differed among the organic fertilizers tested, indicating the usefulness of the method for evaluating suppressiveness by organic fertilizers. Differences in the growth degrees of F. oxysporum were associated with the incidence of disease in spinach on soil treated with organic fertilizers and inoculated with a pathogenic F. oxysporum strain. These results suggested that this method provides some useful information on the suppressiveness of organic fertilizers and soil against Fusarium wilt.
6. An Evaluation Method for the Suppression of Pathogenic Fusarium oxysporum by Soil Microorganisms Using the Dilution Plate Technique
PubMed Central
Mitsuboshi, Masahiro; Kioka, Yuuzou; Noguchi, Katsunori; Asakawa, Susumu
2016-01-01
Soil-borne diseases caused by pathogenic microorganisms are one of the main factors responsible for the decline in crop yields in farmlands. Pathogenic Fusarium oxysporum causes serious damage to various crops, and, thus, a feasible diagnostic method for soil-borne diseases is required. We herein examined a simple method to evaluate the suppressiveness of soil microorganisms against a pathogen by co-cultivating indigenous soil microorganisms and a pathogenic fungus (F. oxysporum f. sp. spinaciae). We inoculated F. oxysporum onto the center of agar medium plates mixed with a dilution series of a suspension of organic fertilizers or soil. After an approximately one-week cultivation, the growth degree of F. oxysporum was estimated based on the size of the colonies that formed on the plates. The growth degree of F. oxysporum significantly differed among the organic fertilizers tested, indicating the usefulness of the method for evaluating suppressiveness by organic fertilizers. Differences in the growth degrees of F. oxysporum were associated with the incidence of disease in spinach on soil treated with organic fertilizers and inoculated with a pathogenic F. oxysporum strain. These results suggested that this method provides some useful information on the suppressiveness of organic fertilizers and soil against Fusarium wilt. PMID:27558588
7. Fracture Toughness of Thin Plates by the Double-Torsion Test Method
NASA Technical Reports Server (NTRS)
2006-01-01
Double torsion testing can produce fracture toughness values without crack length measurement that are comparable to those measured via standardized techniques such as the chevron-notch, surface-crack-in-flexure and precracked beam if the appropriate geometry is employed, and the material does not exhibit increasing crack growth resistance. Results to date indicate that 8 < W/d < 80 and L/W > 2 are required if crack length is not considered in stress intensity calculations. At L/W = 2, the normalized crack length should be 0.35 < a/L < 0.65; whereas for L/W = 3, 0.2 < a/L < 0.75 is acceptable. In addition, the load-points need to roll to reduce friction. For an alumina exhibiting increasing crack growth resistance, values corresponding to the plateau of the R-curve were measured. For very thin plates (W/d > 80) nonlinear effects were encountered.
8. Conversion from film to image plates for transfer method neutron radiography of nuclear fuel
SciTech Connect
Craft, Aaron E.; Papaioannou, Glen C.; Chichester, David L.
9. Non-linear analysis of wave progagation using transform methods and plates and shells using integral equations
Pipkins, Daniel Scott
Two diverse topics of relevance in modern computational mechanics are treated. The first involves the modeling of linear and non-linear wave propagation in flexible, lattice structures. The technique used combines the Laplace Transform with the Finite Element Method (FEM). The procedure is to transform the governing differential equations and boundary conditions into the transform domain where the FEM formulation is carried out. For linear problems, the transformed differential equations can be solved exactly, hence the method is exact. As a result, each member of the lattice structure is modeled using only one element. In the non-linear problem, the method is no longer exact. The approximation introduced is a spatial discretization of the transformed non-linear terms. The non-linear terms are represented in the transform domain by making use of the complex convolution theorem. A weak formulation of the resulting transformed non-linear equations yields a set of element level matrix equations. The trial and test functions used in the weak formulation correspond to the exact solution of the linear part of the transformed governing differential equation. Numerical results are presented for both linear and non-linear systems. The linear systems modeled are longitudinal and torsional rods and Bernoulli-Euler and Timoshenko beams. For non-linear systems, a viscoelastic rod and Von Karman type beam are modeled. The second topic is the analysis of plates and shallow shells under-going finite deflections by the Field/Boundary Element Method. Numerical results are presented for two plate problems. The first is the bifurcation problem associated with a square plate having free boundaries which is loaded by four, self equilibrating corner forces. The results are compared to two existing numerical solutions of the problem which differ substantially. plate. &The bending moments in the non-linear model are compared to those
10. A novel vibration measurement and active control method for a hinged flexible two-connected piezoelectric plate
Qiu, Zhi-cheng; Wang, Xian-feng; Zhang, Xian-Min; Liu, Jin-guo
2018-07-01
A novel non-contact vibration measurement method using binocular vision sensors is proposed for piezoelectric flexible hinged plate. Decoupling methods of the bending and torsional low frequency vibration on measurement and driving control are investigated, using binocular vision sensors and piezoelectric actuators. A radial basis function neural network controller (RBFNNC) is designed to suppress both the larger and the smaller amplitude vibrations. To verify the non-contact measurement method and the designed controller, an experimental setup of the flexible hinged plate with binocular vision is constructed. Experiments on vibration measurement and control are conducted by using binocular vision sensors and the designed RBFNNC controllers, compared with the classical proportional and derivative (PD) control algorithm. The experimental measurement results demonstrate that the binocular vision sensors can detect the low-frequency bending and torsional vibration effectively. Furthermore, the designed RBF can suppress the bending vibration more quickly than the designed PD controller owing to the adjustment of the RBF control, especially for the small amplitude residual vibrations.
11. Conventional plate fixation method versus pre-operative virtual simulation and three-dimensional printing-assisted contoured plate fixation method in the treatment of anterior pelvic ring fracture.
PubMed
Hung, Chun-Chi; Li, Yuan-Ta; Chou, Yu-Ching; Chen, Jia-En; Wu, Chia-Chun; Shen, Hsain-Chung; Yeh, Tsu-Te
2018-05-03
Treating pelvic fractures remains a challenging task for orthopaedic surgeons. We aimed to evaluate the feasibility, accuracy, and effectiveness of three-dimensional (3D) printing technology and computer-assisted virtual surgery for pre-operative planning in anterior ring fractures of the pelvis. We hypothesized that using 3D printing models would reduce operation time and significantly improve the surgical outcomes of pelvic fracture repair. We retrospectively reviewed the records of 30 patients with pelvic fractures treated by anterior pelvic fixation with locking plates (14 patients, conventional locking plate fixation; 16 patients, pre-operative virtual simulation with 3D, printing-assisted, pre-contoured, locking plate fixation). We compared operative time, instrumentation time, blood loss, and post-surgical residual displacements, as evaluated on X-ray films, among groups. Statistical analyses evaluated significant differences between the groups for each of these variables. The patients treated with the virtual simulation and 3D printing-assisted technique had significantly shorter internal fixation times, shorter surgery duration, and less blood loss (- 57 minutes, - 70 minutes, and - 274 ml, respectively; P < 0.05) than patients in the conventional surgery group. However, the post-operative radiological result was similar between groups (P > 0.05). The complication rate was less in the 3D printing group (1/16 patients) than in the conventional surgery group (3/14 patients). The 3D simulation and printing technique is an effective and reliable method for treating anterior pelvic ring fractures. With precise pre-operative planning and accurate execution of the procedures, this time-saving approach can provide a more personalized treatment plan, allowing for a safer orthopaedic surgery.
12. Multipotent Mesenchymal Stromal Stem Cell Expansion by Plating Whole Bone Marrow at a Low Cellular Density: A More Advantageous Method for Clinical Use
PubMed Central
Mareschi, Katia; Rustichelli, Deborah; Calabrese, Roberto; Gunetti, Monica; Sanavio, Fiorella; Castiglia, Sara; Risso, Alessandra; Ferrero, Ivana; Tarella, Corrado; Fagioli, Franca
2012-01-01
Mesenchymal stem cells (MSCs) are a promising source for cell therapy due to their pluripotency and immunomodulant proprieties. As the identification of “optimal” conditions is important to identify a standard procedure for clinical use. Percoll, Ficoll and whole bone marrow directly plated were tested from the same sample as separation methods. The cells were seeded at the following densities: 100 000, 10 000, 1000, 100, 10 cells/cm2. After reaching confluence, the cells were detached, pooled and re-plated at 1000, 500, 100, and 10 cells/cm2. Statistical analyses were performed. Cumulative Population Doublings (PD) did not show significant differences for the separation methods and seeding densities but only for the plating density. Some small quantity samples plated in T25 flasks at plating densities of 10 and 100 cells/cm2 did not produce any expansion. However, directly plated whole bone marrow resulted in a more advantageous method in terms of CFU-F number, cellular growth and minimal manipulation. No differences were observed in terms of gross morphology, differentiation potential or immunophenotype. These data suggest that plating whole bone marrow at a low cellular density may represent a good procedure for MSC expansion for clinical use. PMID:23715383
13. Nouvelle methode d'integration energetique pour la retro-installation des procedes industriels et la transformation des usines papetieres
Bonhivers, Jean-Christophe
The increase in production of goods over the last decades has led to the need for improving the management of natural resources management and the efficiency of processes. As a consequence, heat integration methods for industry have been developed. These have been successful for the design of new plants: the integration principles are largely employed, and energy intensity has dramatically decreased in many processes. Although progress has also been achieved in integration methods for retrofit, these methods still need further conceptual development. Furthermore, methodological difficulties increase when trying to retrofit heat exchange networks that are closely interrelated to water networks, such as the case of pulp and paper mills. The pulp and paper industry seeks to increase its profitability by reducing production costs and optimizing supply chains. Recent process developments in forestry biorefining give this industry the opportunity for diversification into bio-products, increasing potential profit margins, and at the same time modernizing its energy systems. Identification of energy strategies for a mill in a changing environment, including the possibility of adding a biorefinery process on the industrial site, requires better integration methods for retrofit situations. The objective of this thesis is to develop an energy integration method for the retrofit of industrial systems and the transformation of pulp and paper mills, ant to demonstrate the method in case studies. Energy is conserved and degraded in a process. Heat can be converted into electricity, stored as chemical energy, or rejected to the environment. A systematic analysis of successive degradations of energy between the hot utilities until the environment, through process operations and existing heat exchangers, is essential in order to reduce the heat consumption. In this thesis, the "Bridge Method" for energy integration by heat exchanger network retrofit has been developed. This method
14. Various methods of determining the natural frequencies and damping of composite cantilever plates. 2. Approximate solution by Galerkin's method for the trinomial model of damping
Ekel'chik, V. S.; Ryabov, V. M.
1997-01-01
The application of Kantorovich's method to a trinomial model of deformation taking into account transverse bending of a plate leads to a connected system of three ordinary differential equations of fourth order with respect to three unknown functions of the longitudinal coordinate and to the coresponding boundary conditions for them at the fixed end and on the free edge. For the approximate calculation of the frequencies and forms of natural vibrations Galerkin's method is used, and as coordinate functions we chose orthogonal Jacobi polynomials with weight function. The dimensionless frequencies depend on the magnitude of the four dimensionless complexes, three of which characterize the anisotropy of the elastic properties of the composite. For the fibrous composites used at present we determined the possible range of change of the dimensionless complexes d16 and d26 attained by oblique placement. The article examines the influence of the angle of reinforcement on some first dimensionless frequencies of a plate made of unidirectional carbon reinforced plastic. It also analyzes the asymptotics of the frequencies when the length of the plate is increased, and it shows that for strongly anisotropic material with the structure [ϕ]T the frequencies of the flexural as well as of the torsional vibrations may be substantially lower when flexural-torsional interaction is taken into account.
15. Simulative method for determining the optimal operating conditions for a cooling plate for lithium-ion battery cell modules
Smith, Joshua; Hinterberger, Michael; Hable, Peter; Koehler, Juergen
2014-12-01
Extended battery system lifetime and reduced costs are essential to the success of electric vehicles. An effective thermal management strategy is one method of enhancing system lifetime increasing vehicle range. Vehicle-typical space restrictions favor the minimization of battery thermal management system (BTMS) size and weight, making their production and subsequent vehicle integration extremely difficult and complex. Due to these space requirements, a cooling plate as part of a water-glycerol cooling circuit is commonly implemented. This paper presents a computational fluid dynamics (CFD) model and multi-objective analysis technique for determining the thermal effect of coolant flow rate and inlet temperature in a cooling plate-at a range of vehicle operating conditions-on a battery system, thereby providing a dynamic input for one-dimensional models. Traditionally, one-dimensional vehicular thermal management system models assume a static heat input from components such as a battery system: as a result, the components are designed for a set coolant input (flow rate and inlet temperature). Such a design method is insufficient for dynamic thermal management models and control strategies, thereby compromising system efficiency. The presented approach allows for optimal BMTS design and integration in the vehicular coolant circuit.
16. A Pressure Plate-Based Method for the Automatic Assessment of Foot Strike Patterns During Running.
PubMed
Santuz, Alessandro; Ekizos, Antonis; Arampatzis, Adamantios
2016-05-01
The foot strike pattern (FSP, description of how the foot touches the ground at impact) is recognized to be a predictor of both performance and injury risk. The objective of the current investigation was to validate an original foot strike pattern assessment technique based on the numerical analysis of foot pressure distribution. We analyzed the strike patterns during running of 145 healthy men and women (85 male, 60 female). The participants ran on a treadmill with integrated pressure plate at three different speeds: preferred (shod and barefoot 2.8 ± 0.4 m/s), faster (shod 3.5 ± 0.6 m/s) and slower (shod 2.3 ± 0.3 m/s). A custom-designed algorithm allowed the automatic footprint recognition and FSP evaluation. Incomplete footprints were simultaneously identified and corrected from the software itself. The widely used technique of analyzing high-speed video recordings was checked for its reliability and has been used to validate the numerical technique. The automatic numerical approach showed a good conformity with the reference video-based technique (ICC = 0.93, p < 0.01). The great improvement in data throughput and the increased completeness of results allow the use of this software as a powerful feedback tool in a simple experimental setup.
17. Developpement et implementation d'une methode pour resoudre les equations de la couche limite laminaire et turbulente
Leuca, Maxim
CFD (Computational Fluid Dynamics) is a computational tool for studying flow in science and technology. The Aerospace Industry uses increasingly the CFD modeling and design phase of the aircraft, so the precision with which phenomena are simulated boundary layer is very important. The research efforts are focused on optimizing the aerodynamic performance of airfoils to predict the drag and delay the laminar-turbulent transition. CFD codes must be fast and efficient to model complex geometries for aerodynamic flows. The resolution of the boundary layer equations requires a large amount of computing resources for viscous flows. CFD codes are commonly used to simulate aerodynamic flows, require normal meshes to the wall, extremely fine, and, by consequence, the calculations are very expensive. . This thesis proposes a new approach to solve the equations of boundary layer for laminar and turbulent flows using an approach based on the finite difference method. Integrated into a code of panels, this concept allows to solve airfoils avoiding the use of iterative algorithms, usually computing time and often involving convergence problems. The main advantages of panels methods are their simplicity and ability to obtain, with minimal computational effort, solutions in complex flow conditions for relatively complicated configurations. To verify and validate the developed program, experimental data are used as references when available. Xfoil code is used to obtain data as a pseudo references. Pseudo-reference, as in the absence of experimental data, we cannot really compare two software together. Xfoil is a program that has proven to be accurate and inexpensive computing resources. Developed by Drela (1985), this program uses the method with two integral to design and analyze profiles of wings at low speed (Drela et Youngren, 2014), (Drela, 2003). NACA 0012, NACA 4412, and ATR-42 airfoils have been used for this study. For the airfoils NACA 0012 and NACA 4412 the calculations
18. Application of laser ranging and VLBI data to a study of plate tectonic driving forces. [finite element method
NASA Technical Reports Server (NTRS)
Solomon, S. C.
1980-01-01
The measurability of changes in plate driving or resistive forces associated with plate boundary earthquakes by laser rangefinding or VLBI is considered with emphasis on those aspects of plate forces that can be characterized by such measurements. Topics covered include: (1) analytic solutions for two dimensional stress diffusion in a plate following earthquake faulting on a finite fault; (2) two dimensional finite-element solutions for the global state of stress at the Earth's surface for possible plate driving forces; and (3) finite-element solutions for three dimensional stress diffusion in a viscoelastic Earth following earthquake faulting.
19. Electrode Plate For An Eletrlchemical Cell And Having A Metal Foam Type Support, And A Method Of Obtaining Such An Electrode
DOEpatents
Verhoog, Roelof; Precigout, Claude; Stewart, Donald
1996-05-21
The electrode plate includes an active portion that is pasted with active material, and a plate head that is made up of three layers of compressed metal foam comprising: a non-pasted portion of height G of the support of the electrode plate; and two strips of non-pasted metal foam of height R on either side of the non-pasted portion of height G of the support and also extending for an overlap height h.sub.2 over the pasted portion of the support. The plate head includes a zone of reduced thickness including a portion that is maximally compressed, and a transitional portion between said maximally compressed portion and the remainder of the electrode which is of thickness e.sub.2. A portion of said plate head forms a connection tab. The method of obtaining the electrode consists in simultaneously rolling all three layers of metal foam in the plate head, and then in cutting matter away from the plates so as to obtain respective connection tabs.
20. Development of Multiwell-Plate Methods Using Pure Cultures of Methanogens To Identify New Inhibitors for Suppressing Ruminant Methane Emissions.
PubMed
Weimar, M R; Cheung, J; Dey, D; McSweeney, C; Morrison, M; Kobayashi, Y; Whitman, W B; Carbone, V; Schofield, L R; Ronimus, R S; Cook, G M
2017-08-01
Hydrogenotrophic methanogens typically require strictly anaerobic culturing conditions in glass tubes with overpressures of H 2 and CO 2 that are both time-consuming and costly. To increase the throughput for screening chemical compound libraries, 96-well microtiter plate methods for the growth of a marine (environmental) methanogen Methanococcus maripaludis strain S2 and the rumen methanogen Methanobrevibacter species AbM4 were developed. A number of key parameters (inoculum size, reducing agents for medium preparation, assay duration, inhibitor solvents, and culture volume) were optimized to achieve robust and reproducible growth in a high-throughput microtiter plate format. The method was validated using published methanogen inhibitors and statistically assessed for sensitivity and reproducibility. The Sigma-Aldrich LOPAC library containing 1,280 pharmacologically active compounds and an in-house natural product library (120 compounds) were screened against M. maripaludis as a proof of utility. This screen identified a number of bioactive compounds, and MIC values were confirmed for some of them against M. maripaludis and M. AbM4. The developed method provides a significant increase in throughput for screening compound libraries and can now be used to screen larger compound libraries to discover novel methanogen-specific inhibitors for the mitigation of ruminant methane emissions. IMPORTANCE Methane emissions from ruminants are a significant contributor to global greenhouse gas emissions, and new technologies are required to control emissions in the agriculture technology (agritech) sector. The discovery of small-molecule inhibitors of methanogens using high-throughput phenotypic (growth) screening against compound libraries (synthetic and natural products) is an attractive avenue. However, phenotypic inhibitor screening is currently hindered by our inability to grow methanogens in a high-throughput format. We have developed, optimized, and validated a high
1. Effect of the Process Parameters on the Formability, Microstructure, and Mechanical Properties of Thin Plates Fabricated by Rheology Forging Process with Electromagnetic Stirring Method
Jin, Chul Kyu; Jang, Chang Hyun; Kang, Chung Gil
2014-01-01
A thin plate (150 × 150 × 1.2 mm) with embedded corrugation is fabricated using the rheoforming method. Semisolid slurry is created using the electromagnetic stirring (EMS) system, and the thin plate is made with the forging die at the 200-ton hydraulic press. The cross sections and microstructures of the slurry with and without stirring are examined. To investigate the effect of the process parameters on the formability, microstructure, and mechanical properties of thin plate the slurry is subjected to 16 types of condition for the forging experiment. The 16 types included the following conditions: Whether the EMS is applied or not, three fractions of the solid phase at 35, 45 and 55 pct; two compression velocities at 30 and 300 mm s-1; and four different compression pressures—100, 150, 200 and 250 MPa. The thin plate's formability is enhanced at higher punch velocity for compressing the slurry, and fine solid particles are uniformly distributed, which in turn, enhances the plate's mechanical properties. The pressure between 150 and 200 MPa is an appropriate condition to form thin plates. A thin plate without defects can be created when the slurry at 35 pct of the solid fraction (f s) was applied at the compression velocity of 300 mm s-1 and 150 MPa of pressure. The surface state of thin plate is excellent with 220 MPa of tensile strength and 13.5 pct of elongation. The primary particles are fine over the entire plate, and there are no liquid segregation-related defects.
2. Application of linearized inverse scattering methods for the inspection in steel plates embedded in concrete structures
Tsunoda, Takaya; Suzuki, Keigo; Saitoh, Takahiro
2018-04-01
This study develops a method to visualize the state of steel-concrete interface with ultrasonic testing. Scattered waves are obtained by the UT pitch-catch mode from the surface of the concrete. Discrete wavelet transform is applied in order to extract echoes scattered from the steel-concrete interface. Then Linearized Inverse Scattering Methods are used for imaging the interface. The results show that LISM with Born and Kirchhoff approximation provide clear images for the target.
3. Evaluation of the Material Point Method within CTH to Model 2-Dimensional Plate Impact Problems
DTIC Science & Technology
2014-09-01
Howard University . 14. ABSTRACT The material point method (MPM) is a mixed Eulerian and Lagrangian computational method that allows for the... University in Washington, DC, as a second-year graduate student within mechanical engineering. I also attended Howard University for my undergraduate...Kevin Rugirello, Dr Andrew Tonge, Dr Jeffrey Lloyd, Dr Mary Jane Graham, and Dr Gbadebo Owolabi. vi Student Bio I am currently attending Howard
4. Influence of Deposition Conditions on Fatigue Properties of Martensitic Stainless Steel with Tin Film Coated by Arc Ion Plating Method
Fukui, Satoshi; Yonekura, Daisuke; Murakami, Ri-Ichi
The surface properties like roughness etc. strongly influence the fatigue strength of high-tensile steel. To investigate the effect of surface condition and TiN coating on the fatigue strength of high-strength steel, four-point bending fatigue tests were carried out for martensitic stainless steel with TiN film coated using arc ion plating (AIP) method. This study, using samples that had been polished under several size of grind particle, examines the influence of pre-coating treatment on fatigue properties. A 2-µm-thick TiN film was deposited onto the substrate under three kinds of polishing condition. The difference of the hardness originated in the residual stress or thin deformation layer where the difference of the size of grinding particle of the surface polishing. And it leads the transformation of the interface of the substrate and the TiN film and improves fatigue limit.
5. Chapter 17 Sterile Plate-Based Vitrification of Adherent Human Pluripotent Stem Cells and Their Derivatives Using the TWIST Method.
PubMed
Neubauer, Julia C; Stracke, Frank; Zimmermann, Heiko
2017-01-01
Due to their high biological complexity, e.g., their close cell-to-cell contacts, cryopreservation of human pluripotent stem cells with standard slow-rate protocols often is inefficient and can hardly be standardized. Vitrification that means ultrafast freezing already showed very good viability and recovery rates for this sensitive cell system, but is only applicable for low cell numbers, bears a high risk of contamination, and can hardly be implemented under GxP regulations. In this chapter, a sterile plate-based vitrification method for adherent pluripotent stem cells and their derivatives is presented based on a procedure and device for human embryonic stem cells developed by Beier et al. (Cryobiology 66:8-16, 2013). This protocol overcomes the limitations of conventional vitrification procedures resulting in the highly efficient preservation of ready-to-use adherent pluripotent stem cells with the possibility of vitrifying cells in multi-well formats for direct application in high-throughput screenings.
6. Thermodynamic equilibrium solubility measurements in simulated fluids by 96-well plate method in early drug discovery.
PubMed
Bharate, Sonali S; Vishwakarma, Ram A
2015-04-01
7. A refined finite element method for bending analysis of laminated plates integrated with piezoelectric fiber-reinforced composite actuators
Rouzegar, J.; Abbasi, A.
2018-03-01
This research presents a finite element formulation based on four-variable refined plate theory for bending analysis of cross-ply and angle-ply laminated composite plates integrated with a piezoelectric fiber-reinforced composite actuator under electromechanical loading. The four-variable refined plate theory is a simple and efficient higher-order shear deformation theory, which predicts parabolic variation of transverse shear stresses across the plate thickness and satisfies zero traction conditions on the plate free surfaces. The weak form of governing equations is derived using the principle of minimum potential energy, and a 4-node non-conforming rectangular plate element with 8 degrees of freedom per node is introduced for discretizing the domain. Several benchmark problems are solved by the developed MATLAB code and the obtained results are compared with those from exact and other numerical solutions, showing good agreement.
8. A method for calculating strut and splitter plate noise in exit ducts: Theory and verification
NASA Technical Reports Server (NTRS)
Fink, M. R.
1978-01-01
Portions of a four-year analytical and experimental investigation relative to noise radiation from engine internal components in turbulent flow are summarized. Spectra measured for such airfoils over a range of chord, thickness ratio, flow velocity, and turbulence level were compared with predictions made by an available rigorous thin-airfoil analytical method. This analysis included the effects of flow compressibility and source noncompactness. Generally good agreement was obtained. This noise calculation method for isolated airfoils in turbulent flow was combined with a method for calculating transmission of sound through a subsonic exit duct and with an empirical far-field directivity shape. These three elements were checked separately and were individually shown to give close agreement with data. This combination provides a method for predicting engine internally generated aft-radiated noise from radial struts and stators, and annular splitter rings. Calculated sound power spectra, directivity, and acoustic pressure spectra were compared with the best available data. These data were for noise caused by a fan exit duct annular splitter ring, larger-chord stator blades, and turbine exit struts.
9. Quantitative Laser Biospeckle Method for the Evaluation of the Activity of Trypanosoma cruzi Using VDRL Plates and Digital Analysis.
PubMed
Grassi, Hilda Cristina; García, Lisbette C; Lobo-Sulbarán, María Lorena; Velásquez, Ana; Andrades-Grassi, Francisco A; Cabrera, Humberto; Andrades-Grassi, Jesús E; Andrades, Efrén D J
2016-12-01
In this paper we report a quantitative laser Biospeckle method using VDRL plates to monitor the activity of Trypanosoma cruzi and the calibration conditions including three image processing algorithms and three programs (ImageJ and two programs designed in this work). Benznidazole was used as a test drug. Variable volume (constant density) and variable density (constant volume) were used for the quantitative evaluation of parasite activity in calibrated wells of the VDRL plate. The desiccation process within the well was monitored as a function of volume and of the activity of the Biospeckle pattern of the parasites as well as the quantitative effect of the surface parasite quantity (proportion of the object's plane). A statistical analysis was performed with ANOVA, Tukey post hoc and Descriptive Statistics using R and R Commander. Conditions of volume (100μl) and parasite density (2-4x104 parasites/well, in exponential growth phase), assay time (up to 204min), frame number (11 frames), algorithm and program (RCommander/SAGA) for image processing were selected to test the effect of variable concentrations of benznidazole (0.0195 to 20μg/mL / 0.075 to 76.8μM) at various times (1, 61, 128 and 204min) on the activity of the Biospeckle pattern. The flat wells of the VDRL plate were found to be suitable for the quantitative calibration of the activity of Trypanosoma cruzi using the appropriate algorithm and program. Under these conditions, benznidazole produces at 1min an instantaneous effect on the activity of the Biospeckle pattern of T. cruzi, which remains with a similar profile up to 1 hour. A second effect which is dependent on concentrations above 1.25μg/mL and is statistically different from the effect at lower concentrations causes a decrease in the activity of the Biospeckle pattern. This effect is better detected after 1 hour of drug action. This behavior may be explained by an instantaneous effect on a membrane protein of Trypanosoma cruzi that could
10. Sub-Plate Overlap Code Documentation
NASA Technical Reports Server (NTRS)
Taff, L. G.; Bucciarelli, B.; Zarate, N.
1997-01-01
An expansion of the plate overlap method of astrometric data reduction to a single plate has been proposed and successfully tested. Each plate is (artificially) divided into sub-plates which can then be overlapped. This reduces the area of a 'plate' over which a plate model needs to accurately represent the relationship between measured coordinates and standard coordinates. Application is made to non-astrographic plates such as Schmidt plates and to wide-field astrographic plates. Indeed, the method is completely general and can be applied to any type of recording media.
11. Reconstructing mantle heterogeneity with data assimilation based on the back-and-forth nudging method: Implications for mantle-dynamic fitting of past plate motions
Glišović, Petar; Forte, Alessandro
2016-04-01
The paleo-distribution of density variations throughout the mantle is unknown. To address this question, we reconstruct 3-D mantle structure over the Cenozoic era using a data assimilation method that implements a new back-and-forth nudging algorithm. For this purpose, we employ convection models for a compressible and self-gravitating mantle that employ 3-D mantle structure derived from joint seismic-geodynamic tomography as a starting condition. These convection models are then integrated backwards in time and are required to match geologic estimates of past plate motions derived from marine magnetic data. Our implementation of the nudging algorithm limits the difference between a reconstruction (backward-in-time solution) and a prediction (forward-in-time solution) on over a sequence of 5-million-year time windows that span the Cenozoic. We find that forward integration of reconstructed mantle heterogeneity that is constrained to match past plate motions delivers relatively poor fits to the seismic-tomographic inference of present-day mantle heterogeneity in the upper mantle. We suggest that uncertainties in the past plate motions, related for example to plate reorganization episodes, could partly contribute to the poor match between predicted and observed present-day heterogeneity. We propose that convection models that allow tectonic plates to evolve freely in accord with the buoyancy forces and rheological structure in the mantle could provide additional constraints on geologic estimates of paleo-configurations of the major tectonic plates.
12. A method combining immunocapture and PCR amplification in a microtiter plate for the detection of plant viruses and subviral pathogens.
PubMed
Nolasco, G; de Blas, C; Torres, V; Ponz, F
1993-12-15
A method for the detection of RNA viral and subviral plant pathogens was developed that combines pathogen partial purification by solid-phase adsorbed antibodies, reverse transcriptional-polymerase chain reaction (RT-PCR) and quantitation of the amplified products by fluorescence. The reverse transcription of the RNA is performed directly on the retained material without any previous thermal or chemical disruption of the virus particles. The whole procedure can be carried out in a microtiter plate. Its validity has been successfully confirmed for the detection of bean yellow mosaic virus, cherry leafroll virus, cucumber mosaic virus, citrus tristeza virus, grapevine fanleaf virus, potato leafroll virus, pepper mild mottle virus, and tomato spotted wilt virus, as well as the satellite RNA of cucumber mosaic virus and potato spindle tuber viroid. In this procedure virus-specific antibodies can be replaced by monoclonal antibodies against double-stranded RNA, thus offering the possibility of detection when no specific virus antibodies are available, or immunological methods are difficult to use (i.e., subviral pathogens like satellite-RNAs or viroids). The method described has the typical sensitivity of assays based on the polymerase chain reaction, it is not more laborious than ELISA, and an equivalent degree of automation is possible.
13. Phene Plate (PhP) biochemical fingerprinting. A screening method for epidemiological typing of enterococcal isolates.
PubMed
Saeedi, B; Tärnberg, M; Gill, H; Hällgren, A; Jonasson, J; Nilsson, L E; Isaksson, B; Kühn, I; Hanberger, H
2005-09-01
Pulsed-field gel electrophoresis (PFGE) is currently considered the gold standard for genotyping of enterococci. However, PFGE is both expensive and time-consuming. The purpose of this study was to investigate whether the PhP system can be used as a reliable clinical screening method for detection of genetically related isolates of enterococci. If so, it should be possible to minimize the number of isolates subjected to PFGE typing, which would save time and money. Ninety-nine clinical enterococcal isolates were analysed by PhP (similarity levels 0.90-0.975) and PFGE (similarity levels < or =3 and < or =6 bands) and all possible pairs of isolates were cross-classified as matched or mismatched. We found that the probability that a pair of isolates (A and B) belonging to the same type according to PhP also belong to the same cluster according to PFGE, i.e. p(A(PFGE)=B(PFGE) * A(PhP)=B(PhP)), and the probability that a pair of isolates of different types according to PhP also belong to different clusters according to PFGE, i.e. p(A(PFGE) not equalB(PFGE) * A(PhP) not equalB(PhP)), was relatively high for E. faecalis (0.86 and 0.96, respectively), but was lower for E. faecium (0.51 and 0.77, respectively). The concordance which shows the probability that PhP and PFGE agree on match or mismatch was 86%-93% for E. faecalis and 54%-66% for E. faecium, which indicates that the PhP method may be useful for epidemiological typing of E. faecalis in the current settings but not for E. faecium.
14. Preparation of micro/nano-structure superhydrophobic film on aluminum plates using galvanic corrosion method.
PubMed
Wu, Ruomei; Chao, Guang Hua; Jiang, Haiyun; Pan, Anqiang; Chen, Hong; Yuan, Zhiqing; Liu, Qilong
2013-10-01
A simple and novel approach has been developed to obtain a microporous film with compound nanoparticles on the surface of aluminum alloy substrate using the galvanic corrosion method. The wettability of the surface changes from hydrophilicity to superhydrophobicity after chemical modification with stearic acid (SA). The water contact angle (WCA) and sliding angle (WSA) of superhydrophobic aluminum alloy surface (SAAS) are 154 degrees and 9 degrees, respectively. The roughness of the aluminum substrate increases after the oxidation reaction. The porous aluminum matrix surface is covered with irregularly shaped holes with a mean radius of about 15 microm, similar to the surface papillae of natural Lotus leaf, with villus-like nanoparticles array on pore surfaces. The superhydrophobic property is attributed to this special surface morphology and low surface energy SA. X-ray powder diffraction (XRD) pattern and Energy Dispersive X-Ray Spectroscopy (EDS) spectrum indicate that Al2O3, Al(OH)3 and AIO(OH) has been formed on the surface of aluminum substrate after the oxidation reaction. The Raman spectra indicate that C-H bond from SA and the Al-O are formed on the SAAS. The as-formed SAAS has good stability.
15. A novel direct screening method for alkyl glucoside production by glucosidases expressed in E. coli in 96-well plates.
PubMed
Gräber, Martin; Andersson, Mats; Rundbäck, Fabian; Pozzo, Tania; Karlsson, Eva Nordberg; Adlercreutz, Patrick
2010-01-15
The present work describes the development of a novel direct screening method, assayed in 96-well format, for evaluation of enzymatic alkyl glycoside production in a hexanol-water two-phase system. Alkyl glycosides are surfactants with a range of applications and with good biodegradability and low toxicity. Enzymatic synthesis makes it possible to prepare beta-d-glucopyranosides with high purity. In the developed screening assay, hexyl-beta-d-glucopyranoside was chosen as a model product to be synthesised by reversed hydrolysis in a water-hexanol two-phase system. In a first step the model product is produced by glucosidases expressed in E. coli cells in 96-deep-well plates. After phase separation, the hexyl-beta-d-glucopyranoside in the organic phase is degraded enzymatically and the released glucose detected spectrophotometrically at 405nm utilizing peroxidase/glucose oxidase, and the reagent 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS). The aqueous phase is used to monitor hydrolysis of p-NPG at 405nm, allowing use of a ratio of the two assays to compensate for expression differences. The complete method was used for comparison of two different beta-glucosidases, classified under glycoside hydrolase family 1 and 3, respectively, showing a significant difference in their ability to synthesise hexyl-beta-d-glucopyranoside by reversed hydrolysis.
16. Numerical analysis on interactions between fluid flow and structure deformation in plate-fin heat exchanger by Galerkin method
Liu, Jing-cheng; Wei, Xiu-ting; Zhou, Zhi-yong; Wei, Zhen-wen
2018-03-01
The fluid-structure interaction performance of plate-fin heat exchanger (PFHE) with serrated fins in large scale air-separation equipment was investigated in this paper. The stress and deformation of fins were analyzed, besides, the interaction equations were deduced by Galerkin method. The governing equations of fluid flow and heat transfer in PFHE were deduced by finite volume method (FVM). The distribution of strain and stress were calculated in large scale air separation equipment and the coupling situation of serrated fins under laminar situation was analyzed. The results indicated that the interactions between fins and fluid flow in the exchanger have significant impacts on heat transfer enhancement, meanwhile, the strain and stress of fins includes dynamic pressure of the sealing head and flow impact with the increase of flow velocity. The impacts are especially significant at the conjunction of two fins because of the non-alignment fins. It can be concluded that the soldering process and channel width led to structure deformation of fins in the exchanger, and degraded heat transfer efficiency.
17. A correlation method to predict the surface pressure distribution of an infinite plate or a body of revolution from which a jet is issuing
NASA Technical Reports Server (NTRS)
Perkins, S. C., Jr.; Mendenhall, M. R.
1980-01-01
A correlation method to predict pressures induced on an infinite plate by a jet exhausting normal to the plate into a subsonic free stream was extended to jets exhausting at angles to the plate and to jets exhausting normal to the surface of a body revolution. The complete method consisted of an analytical method which models the blockage and entrainment properties of the jet and an empirical correlation which accounts for viscous effects. For the flat plate case, the method was applicable to jet velocity ratios up to ten, jet inclination angles up to 45 deg from the normal, and radial distances up to five diameters from the jet. For the body of revolution case, the method was applicable to a body at zero degrees angle of attack, jet velocity ratios 1.96 and 3.43, circumferential angles around the body up to 25 deg from the jet, axial distances up to seven diameters from the jet, and jet-to-body diameter ratios less than 0.1.
18. Reduction of astrometric plates
NASA Technical Reports Server (NTRS)
Stock, J.
1984-01-01
A rapid and accurate method for the reduction of comet or asteroid plates is described. Projection equations, scale length correction, rotation of coordinates, linearization, the search for additional reference stars, and the final solution are examined.
19. Des ballons pour demain
Régipa, R.
A partir d'une théorie sur la détermination des formes et des contraintes globales d'un ballon de révolution, ou s'en rapprochant, une nouvelle famille de ballons a été définie. Les ballons actuels, dits de forme naturelle'', sont calculés en général pour une tension circonférencielle nulle. Ainsi, pour une mission donnée, la tension longitudinale et la forme de l'enveloppe sont strictement imposées. Les ballons de la nouvelle génération sont globalement cylindriques et leurs pôles sont réunis par un câble axial, chargé de transmettre une partie des efforts depuis le crochet (pôle inférieur), directement au pôle supérieur. De plus, la zone latérale cylindrique est soumise à un faible champ de tensions circonférencielles. Ainsi, deux paramètres permettent de faire évoluer la distribution des tensions et la forme de l'enveloppe: - la tension du câble de liaison entre pôles (ou la longueur de ce câble) - la tension circonférencielle moyenne désirée (ou le rayon du ballon). On peut donc calculer et réaliser: - soit des ballons de forme adaptée, comme les ballons à fond plat pour le bon fonctionnement des montgolfières infrarouge (projet MIR); - soit des ballons optimisés pour une bonne répartition des contraintes et une meilleure utilisation des matériaux d'enveloppe, pour l'ensemble des programmes stratosphériques. Il s'ensuit une économie sensible des coûts de fabrication, une fiabilité accrue du fonctionnement de ces ballons et une rendement opérationnel bien supérieur, permettant entre autres, d'envisager des vols à très haute altitude en matériaux très légers.
20. A study of narrow gap laser welding for thick plates using the multi-layer and multi-pass method
Li, Ruoyang; Wang, Tianjiao; Wang, Chunming; Yan, Fei; Shao, Xinyu; Hu, Xiyuan; Li, Jianmin
2014-12-01
This paper details a new method that combines laser autogenous welding, laser wire filling welding and hybrid laser-GMAW welding to weld 30 mm thick plate using a multi-layer, multi-pass process. A “Y” shaped groove was used to create the joint. Research was also performed to optimize the groove size and the processing parameters. Laser autogenous welding is first used to create the backing weld. The lower, narrowest part of the groove is then welded using laser wire filling welding. Finally, the upper part of the groove is welded using laser-GMAW hybrid welding. Additionally, the wire feeding and droplet transfer behaviors are observed by high speed photography. The two main conclusions from this work are: the wire is often biased towards the side walls, resulting in a lack of fusion at the joint and the creation of other defects for larger groove sizes. Additionally, this results in the droplet transfer behavior becoming unstable, leading to a poor weld appearance for smaller groove sizes.
1. Investigation of the Flow Structure on a Flat Plate Induced by Unsteady Plasma Actuation with DNS Methods
Yu, Jianyang; Chen, Fu; Liu, Huaping; Song, Yanping
2015-12-01
An investigation into the flow characteristic on a flat plate induced by an unsteady plasma was conducted with the methods of direct numerical simulations (DNS). A simplified model of dielectric barrier discharge (DBD) plasma was applied and its parameters were calibrated with the experimental results. In the simulations, effects of the actuation frequency on the flow were examined. The instantaneous flow parameters were also drawn to serve as a detailed study on the behavior when the plasma actuator was applied to the flow. The result shows that induced by the unsteady actuation, a series of vortex pairs which showed dipole formation and periodicity distribution were formed in the boundary layer. The production of these vortex pairs indicated a strong energy exchange between the main flow and the boundary layer. They moved downstream under the action of the free stream and decayed under the influence of the fluid viscosity. The distance of the neighboring vortices was found to be determined by the actuation frequency. Interaction of the neighboring vortices would be ignored when the actuation frequency was too small to make a difference. supported by the Foundation for Innovative Research Groups of National Natural Science Foundation of China (No. 51121004) and National Natural Science Foundation of China (No. 50976026)
2. Simulation of ultrasonic wave propagation in anisotropic poroelastic bone plate using hybrid spectral/finite element method.
PubMed
Nguyen, Vu-Hieu; Naili, Salah
2012-08-01
This paper deals with the modeling of guided waves propagation in in vivo cortical long bone, which is known to be anisotropic medium with functionally graded porosity. The bone is modeled as an anisotropic poroelastic material by using Biot's theory formulated in high frequency domain. A hybrid spectral/finite element formulation has been developed to find the time-domain solution of ultrasonic waves propagating in a poroelastic plate immersed in two fluid halfspaces. The numerical technique is based on a combined Laplace-Fourier transform, which allows to obtain a reduced dimension problem in the frequency-wavenumber domain. In the spectral domain, as radiation conditions representing infinite fluid halfspaces may be exactly introduced, only the heterogeneous solid layer needs to be analyzed by using finite element method. Several numerical tests are presented showing very good performance of the proposed procedure. A preliminary study on the first arrived signal velocities computed by using equivalent elastic and poroelastic models will be presented. Copyright © 2012 John Wiley & Sons, Ltd.
3. Peen plating
NASA Technical Reports Server (NTRS)
Babecki, A. J. (Inventor); Haehner, C. L.
1973-01-01
A process for metal plating which comprises spraying a mixture of metallic powder and small peening particles at high velocity against a surface is described. The velocity must be sufficient to impact and bond metallic powder onto the surface. In the case of metal surfaces, the process has as one of its advantages providing mechanical working (hardening) of the surface simultaneously with the metal plating.
4. Experimental Study on Welded Headed Studs Used In Steel Plate-Concrete Composite Structures Compared with Contactless Method of Measuring Displacement
Kisała, Dawid; Tekieli, Marcin
2017-10-01
5. Visualization and quantification of capillary drainage in the pore space of laminated sandstone by a porous plate method using differential imaging X-ray microtomography
Lin, Qingyang; Bijeljic, Branko; Rieke, Holger; Blunt, Martin J.
2017-08-01
The experimental determination of capillary pressure drainage curves at the pore scale is of vital importance for the mapping of reservoir fluid distribution. To fully characterize capillary drainage in a complex pore space, we design a differential imaging-based porous plate (DIPP) method using X-ray microtomography. For an exemplar mm-scale laminated sandstone microcore with a porous plate, we quantify the displacement from resolvable macropores and subresolution micropores. Nitrogen (N2) was injected as the nonwetting phase at a constant pressure while the porous plate prevented its escape. The measured porosity and capillary pressure at the imaged saturations agree well with helium measurements and experiments on larger core samples, while providing a pore-scale explanation of the fluid distribution. We observed that the majority of the brine was displaced by N2 in macropores at low capillary pressures, followed by a further brine displacement in micropores when capillary pressure increases. Furthermore, we were able to discern that brine predominantly remained within the subresolution micropores, such as regions of fine lamination. The capillary pressure curve for pressures ranging from 0 to 1151 kPa is provided from the image analysis compares well with the conventional porous plate method for a cm-scale core but was conducted over a period of 10 days rather than up to few months with the conventional porous plate method. Overall, we demonstrate the capability of our method to provide quantitative information on two-phase saturation in heterogeneous core samples for a wide range of capillary pressures even at scales smaller than the micro-CT resolution.
6. Plane elasto-plastic analysis of v-notched plate under bending by boundary integral equation method. Ph.D. Thesis
NASA Technical Reports Server (NTRS)
Rzasnicki, W.
1973-01-01
A method of solution is presented, which, when applied to the elasto-plastic analysis of plates having a v-notch on one edge and subjected to pure bending, will produce stress and strain fields in much greater detail than presently available. Application of the boundary integral equation method results in two coupled Fredholm-type integral equations, subject to prescribed boundary conditions. These equations are replaced by a system of simultaneous algebraic equations and solved by a successive approximation method employing Prandtl-Reuss incremental plasticity relations. The method is first applied to number of elasto-static problems and the results compared with available solutions. Good agreement is obtained in all cases. The elasto-plastic analysis provides detailed stress and strain distributions for several cases of plates with various notch angles and notch depths. A strain hardening material is assumed and both plane strain and plane stress conditions are considered.
7. Various methods of determining the natural frequencies and damping of composite cantilever plates. 1. Exact solution for the binomial model of deformation
Skel'chik, V. S.; Ryabov, V. M.
1996-11-01
On the basis of the classical theory of thin anisotropic laminated plates the article analyzes the free vibrations of rectangular cantilever plates made of fibrous composites. The application of Kantorovich's method for the binomial representation of the shape of the elastic surface of a plate yielded for two unknown functions a system of two connected differential equations and the corresponding boundary conditions at the place of constraint and at the free edge. The exact solution for the frequencies and forms of the free vibrations was found with the use of Laplace transformation with respect to the space variable. The magnitudes of several first dimensionless frequencies of the bending and torsional vibrations of the plate were calculated for a wide range of change of two dimensionless complexes, with the dimensions of the plate and the anisotropy of the elastic properties of the material taken into account. The article shows that with torsional vibrations the warping constraint at the fixed end explains the apparent dependence of the shear modulus of the composite on the length of the specimen that had been discovered earlier on in experiments with a torsional pendulum. It examines the interaction and transformation of the second bending mode and of the first torsional mode of the vibrations. It analyzes the asymptotics of the dimensionless frequencies when the length of the plate is increased, and it shows that taking into account the bending-torsion interaction in strongly anisotropic materials type unidirectional carbon reinforced plastic can reduce substantially the frequencies of the bending vibrations but has no effect (within the framework of the binomial model) on the frequencies of the torsional vibrations.
8. A comparative study of biofilm formation by Shiga toxigenic Escherichia coli using epifluorescence microscopy on stainless steel and a microtitre plate method.
PubMed
Rivas, Lucia; Dykes, Gary A; Fegan, Narelle
2007-04-01
Attachment of Shiga toxigenic Escherichia coli (STEC) to surfaces and the formation of biofilms may enhance persistence in a food processing environment and present a risk of contaminating products. Seven strains of STEC and three non-STEC strains were selected to compare two biofilm quantification methods; epifluorescence microscopy on stainless steel (SS) and a microtitre plate assay. The influence of prior growth in planktonic (nutrient broth) and sessile (nutrient agar) culture on biofilm production, as well as expression of surface structures and the possession of antigen 43 (encoded by agn43) on biofilm formation were also investigated. Biofilms were produced in diluted nutrient broth at 25 degrees C for 24 and 48 h. Curli expression was determined using congo red indicator agar, while the presence of agn43 was determined using polymerase chain reaction. No correlation was found between counts for epifluorescence microscopy on SS and the absorbance values obtained with the microtitre plate method for planktonic and sessile grown cultures. Different abilities of individual STEC strains to attach to SS and microtitre plates were found with some strains attaching better to each surface following growth in either planktonic or sessile culture. All O157 STEC strains had low biofilm counts on SS for planktonic and sessile grown cultures; however, one STEC O157:H- strain (EC516) had significantly greater (p<0.05) biofilm production on microtitre plates compared to the other O157 STEC strains. EC516 and other STEC (O174:H21 and O91:H21) strains expressing curli fimbriae were found to produce significantly greater (p<0.05) biofilms on microtitre plates compared to the non-curli expressing strains. No relationship was found between the production of type-I fimbriae, motility, agn43 and bacterial physicochemical properties (previously determined) and biofilm formation on SS or microtitre plates. Variations between the two biofilm determination methods may suggest that
9. A succinct method to generate multi-type HCV beams with a spatial spiral varying retardation-plate
Qi, Junli; Zhang, Hui; Pan, Baoguo; Deng, Haifei; Yang, Jinhong; Shi, Bo; Wang, Hui; Du, Ang; Wang, Weihua; Li, Xiujian
2018-03-01
A simple novel and practical scheme is presented to generate high-power cylindrical vector (HCV) beams with a 36-segment spiral varying retardation-plate sandwiched between two quarter-wave plates (QWPs). Four kinds of HCV beams, such as radially polarized beam and azimuthally polarized beam, are formed by simply rotating two QWPs. A segmented spiral varying phase-plate with isotropy is used to modulate spatial phase distribution to generate in-phase HCV beams. The intensity distributions and polarizing properties of HCV beams are investigated and analyzed in detail. It is demonstrated experimentally that the system can effectively generate multi-type HCV beams with high purity up to 99%, and it can be manufactured as cylindrical vector beam converter commercially.
10. Applying the Explicit Time Central Difference Method for Numerical Simulation of the Dynamic Behavior of Elastoplastic Flexible Reinforced Plates
Yankovskii, A. P.
2017-12-01
Based on a stepwise algorithm involving central finite differences for the approximation in time, a mathematical model is developed for elastoplastic deformation of cross-reinforced plates with isotropically hardening materials of components of the composition. The model allows obtaining the solution of elastoplastic problems at discrete points in time by an explicit scheme. The initial boundary value problem of the dynamic behavior of flexible plates reinforced in their own plane is formulated in the von Kármán approximation with allowance for their weakened resistance to the transverse shear. With a common approach, the resolving equations corresponding to two variants of the Timoshenko theory are obtained. An explicit "cross" scheme for numerical integration of the posed initial boundary value problem has been constructed. The scheme is consistent with the incremental algorithm used for simulating the elastoplastic behavior of a reinforced medium. Calculations of the dynamic behavior have been performed for elastoplastic cylindrical bending of differently reinforced fiberglass rectangular elongated plates. It is shown that the reinforcement structure significantly affects their elastoplastic dynamic behavior. It has been found that the classical theory of plates is as a rule unacceptable for carrying out the required calculations (except for very thin plates), and the first version of the Timoshenko theory yields reasonable results only in cases of relatively thin constructions reinforced by lowmodulus fibers. Proceeding from the results of the work, it is recommended to use the second variant of the Timoshenko theory (as a more accurate one) for calculations of the elastoplastic behavior of reinforced plates.
11. End plate assembly having a two-phase fluid-filled bladder and method for compressing a fuel cell stack
DOEpatents
Carlstrom, Jr., Charles M.
2001-01-01
An end plate assembly is disclosed for use in a fuel cell assembly in which the end plate assembly includes a housing having a cavity, and a bladder receivable in the cavity and engageable with the fuel cell stack. The bladder includes a two-phase fluid having a liquid portion and a vapor portion. Desirably, the two-phase fluid has a vapor pressure between about 100 psi and about 600 psi at a temperature between about 70 degrees C. to about 110 degrees C.
12. Prospective comparative study of two methods for fixation after distal femur corrective osteotomy for valgus deformity; retrograde intramedullary nailing versus less invasive stabilization system plating.
PubMed
Özcan, Çağrı; Sökücü, Sami; Beng, Kubilay; Çetinkaya, Engin; Demir, Bilal; Kabukçuoğlu, Yavuz Selim
2016-10-01
The aim of this study was to compare the radiological and functional results of two different methods of fixation for the correction of femoral valgus deformities. Patients who had undergone osteotomy and correction of a valgus deformity from 2007 to 2013 were prospectively followed. Thirty three patients (20 females, 13 males) with 39 lower limbs were included in the study. Seventeen lower limbs were treated with retrograde intramedullary nailing (IMN) and 22 with less invasive stabilization system plating. Standing orthoroentgenograms of the lower limbs were taken pre-operatively and at the final follow-up. mLDFA, aLDFA, mechanical axis deviation (MAD) were measured in this orthoroentgenograms. Knee osteoarthritis outcome score (KOOS) and knee range of motion were used pre-operatively and at the final follow-up as part of the evaluation of the clinical results. All patients duration of surgery, length of hospital stay were assessed. Operations were performed by two orthopedic surgeons. The choice of correction method for each patient was determined by the surgeon. Pre-operative and post-operative values were simultaneously measured by two additional orthopedic surgeons. The mean age of the patients was 26.2 years (18.0-51.0) in the plating group and 29.3 years (18.0-55.0) in the nailing group. Patients in the plating and nailing groups were followed up for 24.0 (12.0-60.0) and 27.8 (12.0-60.0) months. All patients were followed for a minimum of 12 months. No significant differences were observed between the groups in terms of age, sex, or duration of follow-up (p > 0.05) Comparison of the pre- and post-operative mLDFA, aLDFA, MAD, length of hospital stay, and duration of surgery between the plating group and nailing group, no significant difference was observed between the groups (p > 0.05). However, patients treated with retrograde IMN had significantly better post-operative results in terms of the KOOS and range of motion of the knee according to
13. Method for Performing Aerobic Plate Counts of Anhydrous Cosmetics Utilizing Tween 60 and Arlacel 80 as Dispersing Agents
PubMed Central
McConville, John F.; Anger, Claude B.; Anderson, David W.
1974-01-01
An aqueous diluent containing Tween 60 and Arlacel 80 gave greater recovery of microorganisms when compared with two common diluents as determined by aerobic plate count of inoculated anhydrous cosmetics. The greater recovery was caused by better dispersion of the anhydrous cosmetics in the diluents. Images PMID:4203790
14. Time-alternating method based on single-sideband holography with half-zone-plate processing for the enlargement of viewing zones.
PubMed
Mishina, T; Okano, F; Yuyama, I
1999-06-10
The single-sideband method of holography, as is well known, cuts off beams that come from conjugate images for holograms produced in the Fraunhofer region and from objects with no phase components. The single-sideband method with half-zone-plate processing is also effective in the Fresnel region for beams from an object that has phase components. However, this method restricts the viewing zone to a narrow range. We propose a method to improve this restriction by time-alternating switching of hologram patterns and a spatial filter set on the focal plane of a reconstruction lens.
15. Equivalent modulus method for finite element simulation of the sound absorption of anechoic coating backed with orthogonally rib-stiffened plate
Jin, Zhongkun; Yin, Yao; Liu, Bilong
2016-03-01
The finite element method is often used to investigate the sound absorption of anechoic coating backed with orthogonally rib-stiffened plate. Since the anechoic coating contains cavities, the number of grid nodes of a periodic unit cell is usually large. An equivalent modulus method is proposed to reduce the large amount of nodes by calculating an equivalent homogeneous layer. Applications of this method in several models show that the method can well predict the sound absorption coefficient of such structure in a wide frequency range. Based on the simulation results, the sound absorption performance of such structure and the influences of different backings on the first absorption peak are also discussed.
16. Evaluation of the light scattering and the turbidity microtiter plate-based methods for the detection of the excipient-mediated drug precipitation inhibition.
PubMed
Petruševska, Marija; Urleb, Uroš; Peternel, Luka
2013-11-01
The excipient-mediated precipitation inhibition is classically determined by the quantification of the dissolved compound in the solution. In this study, two alternative approaches were evaluated, one is the light scattering (nephelometer) and other is the turbidity (plate reader) microtiter plate-based methods which are based on the quantification of the compound precipitate. Following the optimization of the nephelometer settings (beam focus, laser gain) and the experimental conditions, the screening of 23 excipients on the precipitation inhibition of poorly soluble fenofibrate and dipyridamole was performed. The light scattering method resulted in excellent correlation (r>0.91) between the calculated precipitation inhibitor parameters (PIPs) and the precipitation inhibition index (PI(classical)) obtained by the classical approach for fenofibrate and dipyridamole. Among the evaluated PIPs AUC100 (nephelometer) resulted in only four false positives and lack of false negatives. In the case of the turbidity-based method a good correlation of the PI(classical) was obtained for the PIP maximal optical density (OD(max), r=0.91), however, only for fenofibrate. In the case of the OD(max) (plate reader) five false positives and two false negatives were identified. In conclusion, the light scattering-based method outperformed the turbidity-based one and could be reliably used for identification of novel precipitation inhibitors. Copyright © 2013 Elsevier B.V. All rights reserved.
17. Fabrication of mandible fracture plate by indirect additive manufacturing
Aizat, M.; Khan, S. F.
2017-10-01
Bone fracture is a serious skeletal injury due to accidents and fragility of the bones at a certain age. In order to accelerate fracture healing process, fracture bone plate is use to hold the fracture segment for more stability. The purpose of this study is to fabricate mandibular fracture plate by using indirect additive manufacturing methods in order to reduce time taken during bending and shaping the fracture fixation plate that conform to the anatomy of the fractured bone site. The design and analysis of the plates are performed using CATIA and ANSYS software. The 3D-CAD data were sent to an additive manufacturing machine (fused filament fabricated) to generate master pattern using PLA and the mould were fabricated using Plaster of Paris. A melt ZAMAK 3 was poured directly into the moulds, and left it until completely harden. 3point bending test was performed on the prototype plate using universal testing machine. Stress-strain curve shows the graph exhibited a linear relationship of stress-strain up to a strain value of 0.001. Specimens give a maximum yielding stress and then break before the conventional deflection. Since the maximum flexural stress and the breaking stress are far apart with a plateau stating at strain value of 0.003mm/mm in most specimens, the specimen’s failure types are considered plastic failure mode. The average thickness and width are 1.65mm and 2.18mm respectively. The flexural modulus and flexural strength are 189.5GPa and 518.1MPa, respectively.
18. Comparison of direct-plating and broth-enrichment culture methods for detection of potential bacterial pathogens in respiratory secretions.
PubMed
Kaur, Ravinder; Wischmeyer, Jareth; Morris, Matthew; Pichichero, Michael E
2017-11-01
We compared the recovery of potential respiratory bacterial pathogens and normal flora from nasopharyngeal specimens collected from children during health and at the onset of acute otitis media (AOM) by selective direct-plating and overnight broth-enrichment. Overall, 3442 nasal wash (NW) samples collected from young children were analysed from a 10-year prospective study. NWs were cultured by (1) direct-plating to TSAII/5 % sheep blood agar and chocolate agar plates and (2) overnight broth-enrichment in BacT/ALERT SA-broth followed by plating. Standard microbiology techniques were applied to identify three dominant respiratory bacterial pathogens: Streptococcus pneumoniae (Spn), Haemophilus influenzae (Hflu) and Moraxella catarrhalis (Mcat) as well as two common nasal flora, Staphylococcus aureus (SA) and alpha-haemolytic Streptococci (AHS).Results/Key findings. Direct-plating of NW resulted in isolation of Spn from 37.8 %, Hflu from 13.6 % and Mcat from 33.2 % of samples. In comparison, overnight broth-enrichment isolated fewer Spn (30.1 %), Hflu (6.2 %) and Mcat (16.2 %) (P<0.001-0.0001). Broth-enrichment resulted in significant increased isolation of SA (6.0 %) and AHS (30.1 %) (P<0.0001). Competition between bacterial species in broth when both species were detected by direct-plating was assessed, and it was found that SA and AHS out-competed other species during broth-enrichment when samples were collected from healthy children but not during AOM. In middle ear fluids (MEF) at the onset of AOM, broth-enrichment resulted in higher recovery of Spn (+10.4 %, P<0.001), Hflu (+4.4 %, P=0.39) and Mcat (+13.5 %, <0.001). Broth-enrichment significantly reduces the accurate detection of bacterial respiratory pathogens and increases identification of SA and AHS in NW. Broth-enrichment improves detection of bacterial respiratory pathogens in MEF samples.
19. Detection of coliform bacteria and Escherichia coli by multiplex polymerase chain reaction: comparison with defined substrate and plating methods for water quality monitoring.
PubMed Central
Bej, A K; McCarty, S C; Atlas, R M
1991-01-01
Multiplex polymerase chain reaction (PCR) and gene probe detection of target lacZ and uidA genes were used to detect total coliform bacteria and Escherichia coli, respectively, for determining water quality. In tests of environmental water samples, the lacZ PCR method gave results statistically equivalent to those of the plate count and defined substrate methods accepted by the U.S. Environmental Protection Agency for water quality monitoring and the uidA PCR method was more sensitive than 4-methylumbelliferyl-beta-D-glucuronide-based defined substrate tests for specific detection of E. coli. Images PMID:1768116
20. Numerical study of the stress-strain state of reinforced plate on an elastic foundation by the Bubnov-Galerkin method
Beskopylny, Alexey; Kadomtseva, Elena; Strelnikov, Grigory
2017-10-01
The stress-strain state of a rectangular slab resting on an elastic foundation is considered. The slab material is isotropic. The slab has stiffening ribs that directed parallel to both sides of the plate. Solving equations are obtained for determining the deflection for various mechanical and geometric characteristics of the stiffening ribs which are parallel to different sides of the plate, having different rigidity for bending and torsion. The calculation scheme assumes an orthotropic slab having different cylindrical stiffness in two mutually perpendicular directions parallel to the reinforcing ribs. An elastic foundation is adopted by Winkler model. To determine the deflection the Bubnov-Galerkin method is used. The deflection is taken in the form of an expansion in a series with unknown coefficients by special polynomials, which are a combination of Legendre polynomials.
1. An Evaluation Method for Suppression of Pathogenic Fusarium oxysporum by Soil Microorganisms Using the Dilution Plate Technique.
PubMed
Mitsuboshi, Masahiro; Kioka, Yuuzou; Noguchi, Katsunori; Asakawa, Susumu
2017-01-01
Volume 31, No. 3, Page 307-313, 2016Page 310, Legend for Fig. 4 IncorrectFig. 4. Growth degree of Fusarium oxysporum f. sp. spinaciae for organic fertilizers at each dilution based on an estimation of the ellipse area (A) and extension length (B) of the colony. Cont, compound inorganic fertilizer; SBM, steamed bone meal; CDC, cow dung compost; MI, microbial inoculant. Values show mean of medians of degrees with SE (n=3). The ellipse area and extension length for control plates were 4,475 mm 2 and 36.5 mm, respectively. CorrectFig. 4. Growth degree of Fusarium oxysporum f. sp. spinaciae for organic fertilizers at each dilution based on an estimation of the ellipse area (A) and extension length (B) of the colony. Cont, compound inorganic fertilizer; SBM, steamed bone meal; CDC, cow dung compost; MI, microbial inoculant. Values show mean of growth degrees with SE (n=3). The ellipse area and extension length for control plates were 4,475 mm 2 and 36.5 mm, respectively. Page 311, Legend for Fig. 5 IncorrectFig. 5. Growth degree of Fusarium oxysporum f. sp. spinaciae for soil applied with organic fertilizers at each dilution based on an estimation of the ellipse area (A) and extension length (B) of the colony. Cont, compound inorganic fertilizer; SBM, steamed bone meal; CDC, cow dung compost; MI, microbial inoculant. Values show the mean of medians of degrees with SE (n=3). The ellipse area and extension length for control plates were 5,473 mm 2 and 40.5 mm, respectively. CorrectFig. 5. Growth degree of Fusarium oxysporum f. sp. spinaciae for soil applied with organic fertilizers at each dilution based on an estimation of the ellipse area (A) and extension length (B) of the colony. Cont, compound inorganic fertilizer; SBM, steamed bone meal; CDC, cow dung compost; MI, microbial inoculant. Values show the mean of growth degrees with SE (n=3). The ellipse area and extension length for control plates were 5,473 mm 2 and 40.5 mm, respectively. Page 312, Legend
2. Design factors of femur fracture fixation plates made of shape memory alloy based on the Taguchi method by finite element analysis.
PubMed
Ko, Cheolwoong; Yang, Mikyung; Byun, Taemin; Lee, Sang-Wook
2018-05-01
This study proposed a way to design femur fracture fixation plates made of shape memory alloy based on computed tomography (CT) images of Korean cadaveric femurs. To this end, 3 major design factors of femur fracture fixation plates (circumference angle, thickness, and inner diameter) were selected based on the contact pressure when a femur fracture fixation plate was applied to a cylinder model using the Taguchi method. Then, the effects of the design factors were analyzed. It was shown that the design factors were statistically significant at a level of p = 0.05 concerning the inner diameter and the thickness. The factors affecting the contact pressure were inner diameter, thickness, and circumference angle, in that order. Particularly, in the condition of Case 9 (inner diameter 27 mm, thickness 2.4 mm, and circumference angle 270°), the max. average contact pressure was 21.721 MPa, while the min. average contact pressure was 3.118 MPa in Case 10 (inner diameter 29 mm, thickness 2.0 mm, and circumference angle 210°). When the femur fracture fixation plate was applied to the cylinder model, the displacement due to external sliding and pulling forces was analyzed. As a result, the displacement in the sliding condition was at max. 3.75 times greater than that in the pulling condition, which indicated that the cohesion strength between the femur fracture fixation plate and the cylinder model was likely to be greater in the pulling condition. When a human femur model was applied, the max. average contact pressure was 10.76 MPa, which was lower than the yield strength of a human femur (108 MPa). In addition, the analysis of the rib behaviors of the femur fracture fixation plate in relation to the recovery effect of the shape memory alloy showed that the rib behaviors varied depending on the arbitrarily curved shapes of the femur sections. Copyright © 2018 John Wiley & Sons, Ltd.
3. A Visualization Method for Corrosion Damage on Aluminum Plates Using an Nd:YAG Pulsed Laser Scanning System.
PubMed
Lee, Inbok; Zhang, Aoqi; Lee, Changgil; Park, Seunghee
2016-12-16
This paper proposes a non-contact nondestructive evaluation (NDE) technique that uses laser-induced ultrasonic waves to visualize corrosion damage in aluminum alloy plate structures. The non-contact, pulsed-laser ultrasonic measurement system generates ultrasonic waves using a galvanometer-based Q-switched Nd:YAG laser and measures the ultrasonic waves using a piezoelectric (PZT) sensor. During scanning, a wavefield can be acquired by changing the excitation location of the laser point and measuring waves using the PZT sensor. The corrosion damage can be detected in the wavefield snapshots using the scattering characteristics of the waves that encounter corrosion. The structural damage is visualized by calculating the logarithmic values of the root mean square (RMS), with a weighting parameter to compensate for the attenuation caused by geometrical spreading and dispersion of the waves. An intact specimen is used to conduct a comparison with corrosion at different depths and sizes in other specimens. Both sides of the plate are scanned with the same scanning area to observe the effect of the location where corrosion has formed. The results show that the damage can be successfully visualized for almost all cases using the RMS-based functions, whether it formed on the front or back side. Also, the system is confirmed to have distinguished corroded areas at different depths.
4. A Visualization Method for Corrosion Damage on Aluminum Plates Using an Nd:YAG Pulsed Laser Scanning System
PubMed Central
Lee, Inbok; Zhang, Aoqi; Lee, Changgil; Park, Seunghee
2016-01-01
This paper proposes a non-contact nondestructive evaluation (NDE) technique that uses laser-induced ultrasonic waves to visualize corrosion damage in aluminum alloy plate structures. The non-contact, pulsed-laser ultrasonic measurement system generates ultrasonic waves using a galvanometer-based Q-switched Nd:YAG laser and measures the ultrasonic waves using a piezoelectric (PZT) sensor. During scanning, a wavefield can be acquired by changing the excitation location of the laser point and measuring waves using the PZT sensor. The corrosion damage can be detected in the wavefield snapshots using the scattering characteristics of the waves that encounter corrosion. The structural damage is visualized by calculating the logarithmic values of the root mean square (RMS), with a weighting parameter to compensate for the attenuation caused by geometrical spreading and dispersion of the waves. An intact specimen is used to conduct a comparison with corrosion at different depths and sizes in other specimens. Both sides of the plate are scanned with the same scanning area to observe the effect of the location where corrosion has formed. The results show that the damage can be successfully visualized for almost all cases using the RMS-based functions, whether it formed on the front or back side. Also, the system is confirmed to have distinguished corroded areas at different depths. PMID:27999252
5. Prosthetic plate mandibular reconstruction.
PubMed
Davidson, M J; Gullane, P J
1991-12-01
The head and neck surgeon may choose one of several available methods to reconstruct the mandible following tumor ablation. This article discusses the use of metallic mandibular prostheses, the indications for alloplastic mandibular reconstruction, techniques of plate application (AO and THRP), and associated complications.
6. Identification of Lactobacillus delbrueckii and Streptococcus thermophilus Strains Present in Artisanal Raw Cow Milk Cheese Using Real-time PCR and Classic Plate Count Methods.
PubMed
Stachelska, Milena A
2017-12-04
The aim of this paper was to detect Lactobacillus delbrueckii and Streptococcus thermophilus using real-time quantitative PCR assay in 7-day ripening cheese produced from unpasteurised milk. Real-time quantitative PCR assays were designed to identify and enumerate the chosen species of lactic acid bacteria (LAB) in ripened cheese. The results of molecular quantification and classic bacterial enumeration showed a high level of similarity proving that DNA extraction was carried out in a proper way and that genomic DNA solutions were free of PCR inhibitors. These methods revealed the presence of L. delbrueckii and S. thermophilus. The real-time PCR enabled quantification with a detection of 101-103 CFU/g of product. qPCR-standard curves were linear over seven log units down to 101 copies per reaction; efficiencies ranged from 77.9% to 93.6%. Cheese samples were analysed with plate count method and qPCR in parallel. Compared with the classic plate count method, the newly developed qPCR method provided faster and species specific identification of two dairy LAB and yielded comparable quantitative results.
7. Lectin-binding histochemistry of non-decalcified growth plate cartilage: a postembedment method for light microscopy of epon-embedded tissue.
PubMed
Farnum, C E; Wilsman, N J
1984-06-01
A postembedment method for the localization of lectin-binding glycoconjugates was developed using Epon-embedded growth plate cartilage from Yucatan miniature swine. By testing a variety of etching, blocking, and incubation procedures, a standard protocol was developed for 1 micron thick sections that allowed visualization of both intracellular and extracellular glycoconjugates with affinity for wheat germ agglutinin and concanavalin A. Both fluorescent and peroxidase techniques were used, and comparisons were made between direct methods and indirect methods using the biotin-avidin bridging system. Differential extracellular lectin binding allowed visualization of interterritorial , territorial, and pericellular matrices. Double labeling experiments showed the precision with which intracellular binding could be localized to specific cytoplasmic compartments, with resolution of binding to the Golgi apparatus, endoplasmic reticulum, and nuclear membrane at the light microscopic level. This method allows the localization of both intracellular and extracellular lectin-binding glycoconjugates using fixation and embedment procedures that are compatible with simultaneous ultrastructural analysis. As such it should have applicability both to the morphological analysis of growth plate organization during normal endochondral ossification, as well as to the diagnostic pathology of matrix abnormalities in disease states of growing cartilage.
8. Limb lengthening over plate
PubMed Central
Kulkarni, Ruta; Singh, Nishant; Kulkarni, Govind S; Kulkarni, Milind; Kulkarni, Sunil; Kulkarni, Vidisha
2012-01-01
Background: The limb lengthening over plate eliminates the associated risk of infection with limb lengthening over intramedullary nail. We present our experience of limb lengthening in 15 patients with a plate fixed on the proximal segment, followed by corticotomy and application of external fixator. Materials and Methods: 15 patients (7 females, 8 males) were included in this consecutive series. The average age was 18.1 years (range 8–35 years). Fifteen tibiae and one femur were lengthened in 15 patients. Lengthening was achieved at 1 mm/day followed by distal segment fixation with three or four screws on reaching the target length. Results: The preoperative target length was successfully achieved in all patients at a mean of 4.1 cm (range 1.8–6.5 cm). The mean duration of external fixation was 75.3 days (range 33–116 days) with the mean external fixation index at 19.2 days/cm (range 10.0–38.3 days/cm). One patient suffered deep infection up to the plate, three patients had mild procurvatum deformities, and one patient developed mild tendo achilles contracture. Conclusion: Lengthening over a plate allows early removal of external fixator and eliminates the risk of creating deep intramedullary infection as with lengthening over nail. Lengthening over plate is also applicable to children with open physis. PMID:22719123
9. A new chemical approach to optimize the in vitro SPF method on the HD6 PMMA plate.
PubMed
Marguerie, S; Pissavini, M; Baud, A; Carayol, T; Doucet, O
2012-01-01
In a previous study, we demonstrated that control of the roughness of molded PMMA plates improves in vitro SPF reproducibility. However, in vitro/vivo deviations are still observed. Sunscreens show different behavior during spreading on the HD6 surface according to the formulation, resulting in a more or less homogenous distribution. The hydrophilic nature of HD6 appears to contribute significantly during spreading. Two different sunscreens offering a homogenous and non-homogenous distribution were investigated to check if the interfacial tension between product and substrate has a real influence on the spreading quality. Using microscopic observations, we attempted to correlate the in vitro SPF results with the product's spreading property. In order to reduce this interfacial tension, an HD6 pretreatment with an amphoteric surfactant, cocamidopropyl betain, was performed. In vitro SPF on "pretreated HD6" was examined using a cohort of 30 products. This pretreatment led to reliable results, demonstrating good association with the in vivo SPF.
10. Metal vapor arc ion plating
DOEpatents
Bertram, L.A.; Fisher, R.W.; Mattox, D.M.; Zanner, F.J.
1986-09-09
A method and apparatus for ion plating are described. The apparatus uses more negative than a first electrode voltage in a vacuum arc remelt system to attract low energy ions from the anode electrode to the article to be plated. 2 figs.
11. Application of Microbiological Method Direct Epifluorescence Filter Techique/Aerobic Plate Count Agar in the Identification of Irradiated Herbs and Spices
PubMed Central
Di Schiavi, Maria Teresa; Foti, Marina; Mosconi, Maria Cristina; Mattiolo, Giuseppina; Cavallina, Roberta
2014-01-01
Irradiation is a preservation technology used to improve the safety and hygienic quality of food. Aim of this study was to assess the applicability and validity of the microbiological screening method direct epifluorescence filter technique (DEFT)/aerobic plate count (APC) (EN 13783:2001) for the identification of irradiated herbs and spices. Tests on non-irradiated and irradiated samples of dried herbs and spices were performed. The method was based on the comparison of APC and count obtained using DEFT. In accordance with the standard reference, this method is not applicable to samples with APC<103 colony forming units (CFU)/g and this is its main limit. The results obtained in our laboratories showed that in 50% of cases of non-irradiated samples and in 96% of the samples treated with ionising radiation, the method was not applicable due to a value of CFU/g <103. PMID:27800348
12. Adhesive Defect Monitoring of Glass Fiber Epoxy Plate Using an Impedance-Based Non-Destructive Testing Method for Multiple Structures
PubMed Central
Na, Wongi S.; Baek, Jongdae
2017-01-01
The emergence of composite materials has revolutionized the approach to building engineering structures. With the number of applications for composites increasing every day, maintaining structural integrity is of utmost importance. For composites, adhesive bonding is usually the preferred choice over the mechanical fastening method, and monitoring for delamination is an essential factor in the field of composite materials. In this study, a non-destructive method known as the electromechanical impedance method is used with an approach of monitoring multiple areas by specifying certain frequency ranges to correspond to a certain test specimen. Experiments are conducted using various numbers of stacks created by attaching glass fiber epoxy composite plates onto one another, and two different debonding damage types are introduced to evaluate the performance of the multiple monitoring electromechanical impedance method. PMID:28629194
13. A 96-well-plate-based optical method for the quantitative and qualitative evaluation of Pseudomonas aeruginosa biofilm formation and its application to susceptibility testing.
PubMed
Müsken, Mathias; Di Fiore, Stefano; Römling, Ute; Häussler, Susanne
2010-08-01
A major reason for bacterial persistence during chronic infections is the survival of bacteria within biofilm structures, which protect cells from environmental stresses, host immune responses and antimicrobial therapy. Thus, there is concern that laboratory methods developed to measure the antibiotic susceptibility of planktonic bacteria may not be relevant to chronic biofilm infections, and it has been suggested that alternative methods should test antibiotic susceptibility within a biofilm. In this paper, we describe a fast and reliable protocol for using 96-well microtiter plates for the formation of Pseudomonas aeruginosa biofilms; the method is easily adaptable for antimicrobial susceptibility testing. This method is based on bacterial viability staining in combination with automated confocal laser scanning microscopy. The procedure simplifies qualitative and quantitative evaluation of biofilms and has proven to be effective for standardized determination of antibiotic efficiency on P. aeruginosa biofilms. The protocol can be performed within approximately 60 h.
14. A direct numerical method for predicting concentration profiles in a turbulent boundary layer over a flat plate. M.S. Thesis
NASA Technical Reports Server (NTRS)
Dow, J. W.
1972-01-01
A numerical solution of the turbulent mass transport equation utilizing the concept of eddy diffusivity is presented as an efficient method of investigating turbulent mass transport in boundary layer type flows. A FORTRAN computer program is used to study the two-dimensional diffusion of ammonia, from a line source on the surface, into a turbulent boundary layer over a flat plate. The results of the numerical solution are compared with experimental data to verify the results of the solution. Several other solutions to diffusion problems are presented to illustrate the versatility of the computer program and to provide some insight into the problem of mass diffusion as a whole.
15. Brewster-plate spoiler - A novel method for reducing the amplitude of interference fringes that limit tunable-laser absorption sensitivities
NASA Technical Reports Server (NTRS)
Webster, C. R.
1985-01-01
A simple method is described for substantially reducing the amplitude of interference fringes that limit the sensitivities of tunable-laser high-resolution absorption spectrometers. A lead-salt diode laser operating in the 7-micron region is used with a single Brewster-plate spoiler to reduce the fringe amplitude by a factor of 30 and also to allow the detection of absorptances 0.001 percent in a single laser scan without subtraction techniques, without complex frequency modulation, and without distortion of the molecular line-shape signals. Application to multipass-cell spectrometers is described.
16. Quantitative Urine Culture Method Using a Plastic „Paddle” Containing Dual Media
PubMed Central
Craig, William A.; Kunin, Calvin M.
1972-01-01
A new dip-inoculum method for quantitative urine culture is described which utilizes a dual-chambered plastic „paddle” housing both a general purpose and differential medium. Comparative bacterial counts of 1,000 clinical specimens using the pour plate and this device were identical in 82.9% and within a factor of five in 95.6%. The „paddle” detected all but 19 of 258 specimens (92.6%) with 100,000 or greater colonies per ml. This simple, convenient method should allow more extensive use of quantitative urine culture in the diagnosis and follow-up of patients with urinary tract infections in office practice. It should not be considered as a substitute for the more definitive pour plate method or for standard methods for characterization of bacteriological species when more exact information is required. PMID:4555636
17. Time Dependent Antinociceptive Effects of Morphine and Tramadol in the Hot Plate Test: Using Different Methods of Drug Administration in Female Rats
PubMed Central
Gholami, Morteza; Saboory, Ehsan; Mehraban, Sogol; Niakani, Afsaneh; Banihabib, Nafiseh; Azad, Mohamad-Reza; Fereidoni, Javid
2015-01-01
18. Electrochemical Assay of Gold-Plating Solutions
NASA Technical Reports Server (NTRS)
Chiodo, R.
1982-01-01
Gold content of plating solution is assayed by simple method that required only ordinary electrochemical laboratory equipment and materials. Technique involves electrodeposition of gold from solution onto electrode, the weight gain of which is measured. Suitable fast assay methods are economically and practically necessary in electronics and decorative-plating industries. If gold content in plating bath is too low, poor plating may result, with consequent economic loss to user.
19. Use of the bioactive resorbable plate system for zygoma and zygomatic arch replacement and fixation with modified Crockett's method for maxillectomy: A technical note.
PubMed
Sukegawa, Shintaro; Kanno, Takahiro; Shibata, Akane; Matsumoto, Kenichi; Sukegawa-Takahashi, Yuka; Sakaida, Kyousuke; Furuki, Yoshihiko
2017-07-01
As a surgical approach targeting the pterygopalatine fossa following maxillary cancer due to tumor invasion, Crockett's method is conventional and useful. However, if the tumor is confined to the area between the maxilla and pterygopalatine fossa, it is not necessary to include the zygomatico-orbital in the access osteotomy, and the orbital floor may be preserved. Depending on the range of tumor invasion, the current study reports a more minimally invasive, modified Crockett's surgery that may be considered, which includes resection with modified osteotomy lines and repositioning with fixation of the zygoma and zygomatic arch following maxillary cancer ablation. In addition, the majority of patients with advanced maxillary cancer may require postoperative radiotherapy or chemoradiotherapy following maxillectomy according to several guidelines. Therefore, using a low-profile bioactive resorbable plate system as a method of repositioning and fixing the resected and preserved zygoma and zygomatic arch may be more effective in this modified Crockett's method for maxillectomy.
20. An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array.
PubMed
Yan, Gang; Zhou, Li
2018-02-21
This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method.
1. An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array
PubMed Central
Zhou, Li
2018-01-01
This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method. PMID:29466310
2. Development of Microtiter Plate Culture Method for Rapid Screening of ε-Poly-L-Lysine-Producing Strains.
PubMed
Liu, Yong-Juan; Chen, Xu-Sheng; Zhao, Jun-Jie; Pan, Long; Mao, Zhong-Gui
2017-12-01
ε-Poly-L-lysine (ε-PL) produced by Streptomyces albulus possesses a broad spectrum of antimicrobial activity and is widely used as a food preservative. To extensively screen ε-PL-overproducing strain, we developed an integrated high-throughput screening assay using ribosome engineering technology. The production protocol was scaled down to 24- and 48-deep-well microtiter plates (MTPs). The microplate reader assay was used to monitor ε-PL production. A good correlation was observed between the fermentation results obtained in both 24-(48)-deep-well MTPs and conventional Erlenmeyer flasks. Using this protocol, the production of ε-PL in an entire MTP was determined in <5 min without compromising on accuracy. The high-yielding strain selected through this protocol was also tested in Erlenmeyer flasks. The result showed that the ε-PL production of the high-yielding mutants was nearly 45% higher than that of the parent stain. Thus, development of this protocol is expected to accelerate the selection of ε-PL-overproducing strains.
3. A functional dual-coated (FDC) microtiter plate method to replace the botulinum toxin LD50 test.
PubMed
Liu, Yvonne Y B; Rigsby, Peter; Sesardic, Dorothea; Marks, James D; Jones, Russell G A
2012-06-01
Conventional capture ("Sandwich") ELISAs equally detect denatured inactive and native active botulinum type A toxin. Light chain endoprotease activity assays also fail to distinguish between various inactive molecules including partially denatured and fragmented material still retaining this protease activity. By co-coating microtiter plates with SNAP25 substrate and a monoclonal antibody specific for a conformational epitope of the toxin's Hc domain, it was possible to develop a highly sensitive (130 aM LoD), precise (1.4% GCV) new assay specific for the biologically active toxin molecule. Capture was performed in phosphate buffer with a fixed optimal concentration of chaotropic agent (e.g., 1.2 M urea) to differentially isolate functional toxin molecules. Addition of enzymatically favorable buffer containing zinc and DTT reduced the interchain disulfide bond releasing and activating the captured L-chain with subsequent specific cleavage of the SNAP25(1-206) substrate. A neoepitope antibody specific for the newly exposed Q(197) epitope was used to quantify the cleaved SNAP25(1-197). The assay's requirement for the intact toxin molecule was demonstrated with pre-reduced toxin (heavy and light chains), recombinant LHn fragments, and stressed samples containing partially or fully denatured material. This is the first known immunobiochemical assay that correlates with in vivo potency and provides a realistic alternative. Copyright © 2012 Elsevier Inc. All rights reserved.
4. Plating Processes Utilizing High Intensity Acoustic Beams
NASA Technical Reports Server (NTRS)
Oeftering, Richard C. (Inventor); Denofrio, Charles (Inventor)
2002-01-01
A system and a method for selective plating processes are disclosed which use directed beams of high intensity acoustic waves to create non-linear effects that alter and improve the plating process. The directed beams are focused on the surface of an object, which in one embodiment is immersed in a plating solution, and in another embodiment is suspended above a plating solution. The plating processes provide precise control of the thickness of the layers of the plating, while at the same time, in at least some incidents, eliminates the need for masking.
5. Developpement d'un modele analytique pour l'analyse en elasticite lineaire de champs de deformation et contrainte au sein d'un polycristal. comparaison avec la methode des elements finis =
Bretin, Remy
L'endommagement par fatigue des materiaux est un probleme courant dans de nombreux domaines, dont celui de l'aeronautique. Afin de prevenir la rupture par fatigue des materiaux il est necessaire de determiner leur duree de vie en fatigue. Malheureusement, dues aux nombreuses heterogeneites presentes, la duree de vie en fatigue peut fortement varier entre deux pieces identiques faites dans le meme materiau ayant subi les memes traitements. Il est donc necessaire de considerer ces heterogeneites dans nos modeles afin d'avoir une meilleure estimation de la duree de vie des materiaux. Comme premiere etape vers une meilleure consideration des heterogeneites dans nos modeles, une etude en elasticite lineaire de l'influence des orientations cristallographiques sur les champs de deformations et de contraintes dans un polycristal a ete realisee a l'aide de la methode des elements finis. Des correlations ont pu etre etablies a partir des resultats obtenus, et un modele analytique en elasticite lineaire prenant en compte les distributions d'orientations cristallographiques et les effets de voisinage a pu etre developpe. Ce modele repose sur les bases des modeles d'homogeneisation classique, comme le schema auto-coherent, et reprend aussi les principes de voisinage des automates cellulaires. En prenant pour reference les resultats des analyses elements finis, le modele analytique ici developpe a montre avoir une precision deux fois plus grande que le modele auto-coherent, quel que soit le materiau etudie.
6. When It Rains, It Pours
ERIC Educational Resources Information Center
Mills, Linda
2012-01-01
"It's raining, it's pouring, the old man is snoring!" "The itsy, bitsy spider crawled up the waterspout, down came the rain and washed the spider out. Out came the sun and dried up all the rain, and the itsy, bitsy spider went up the spout again." What do children's nursery rhymes have to do with the school library? The author begins by telling a…
7. Corrugated cover plate for flat plate collector
DOEpatents
Hollands, K. G. Terry; Sibbitt, Bruce
1978-01-01
A flat plate radiant energy collector is providing having a transparent cover. The cover has a V-corrugated shape which reduces the amount of energy reflected by the cover away from the flat plate absorber of the collector.
8. Elastic plate spallation
NASA Technical Reports Server (NTRS)
Oline, L.; Medaglia, J.
1972-01-01
The dynamic finite element method was used to investigate elastic stress waves in a plate. Strain displacement and stress strain relations are discussed along with the stiffness and mass matrix. The results of studying point load, and distributed load over small, intermediate, and large radii are reported. The derivation of finite element matrices, and the derivation of lumped and consistent matrices for one dimensional problems with Laplace transfer solutions are included. The computer program JMMSPALL is also included.
9. Electrically induced mechanical precompression of ferroelectric plates
DOEpatents
Chen, P.J.
1987-03-02
A method of electrically inducing mechanical precompression of ferroelectric plate covered with electrodes utilizes the change in strains of the plate as functions of applied electric field. A first field polarizes and laterally shrinks the entire plate. An outer portion of the electrodes are removed, and an opposite field partially depolarizes and expands the central portion of the plate against the shrunk outer portion. 2 figs.
10. Electrically induced mechanical precompression of ferroelectric plates
DOEpatents
Chen, Peter J.
1987-01-01
A method of electrically inducing mechanical precompression of a ferroelectric plate covered with electrodes utilizes the change in strains of the plate as functions of applied electric field. A first field polarizes and laterally shrinks the entire plate. An outer portion of the electrodes are removed, and an opposite field partially depolarizes and expands the central portion of the plate against the shrunk outer portion.
11. Plates-formes de microscopie et fluorescence par resonance de plasmons de surface appliquees a l'imagerie cellulaire
Chabot, Vincent
L'elaboration de nouveaux medicaments repose sur les etudes pharmacologiques, dont le role est d'identifier de nouveaux composes actifs ou de nouvelles cibles pharmacologiques agissant entre autres au niveau cellulaire. Recemment, la detection basee sur la resonance des plasmons de surface (SPR) a ete appliquee a l'etude de reponses cellulaires. Cette methode de detection, permettant d'observer des variations d'indice de refraction associes a de faibles changements de masse a la surface d'un metal, a l'avantage de permettre l'etude d'une population de cellules vivantes en temps reel, sans necessiter l'introduction d'agents de marquage. Pour effectuer la detection au niveau de cellules individuelles, on peut employer la microscopie SPR, qui consiste a localiser spatialement la detection par un systeme d'imagerie. Cependant, la detection basee sur la SPR est une mesure sans marquage et les signaux mesures sont attribues a une reponse moyennee des differentes sources cellulaires. Afin de mieux comprendre et identifier les composantes cellulaires generant le signal mesure en SPR, il est pertinent de combiner la microscopie SPR avec une modalite complementaire, soit l'imagerie de fluorescence. C'est dans cette problematique que s'insere ce projet de these, consistant a concevoir deux plates-formes distinctes de microscopie SPR et de fluorescence optimisees pour l'etude cellulaire, de sorte a evaluer les possibilites d'integration de ces deux modalites en un seul systeme. Des substrats adaptes pour chaque plate-forme ont ete concus et realises. Ces substrats employaient une couche d'argent passivee par l'ajout d'une mince couche d'or. La stabilite et la biocompatibilite des substrats ont ete validees pour l'etude cellulaire. Deux configurations permettant d'ameliorer la sensibilite en sondant les cellules plus profondement ont ete evaluees, soit l'emploi de plasmons de surface a longue portee et de guides d'onde a gaine metallique. La sensibilite accrue de ces
12. Effects of artificial settlement plate materials and methods of deployment on the sessile epibenthic community development in a tropical environment
Field, S. N.; Glassom, D.; Bythell, J.
2007-06-01
The choice of substrata and the methods of deployment in analyses of settlement in benthic communities are often driven by the cost of materials and their local availability, and comparisons are often made between studies using different methodologies. The effects of varying artificial substratum, size of replicates and method of deployment were determined on a shallow reef in Eilat, Israel, while the effect of size of replicates was also investigated on a shallow reef in Sharm El Sheikh, Egypt. When statistical power was high enough, that is, when sufficient numbers of settlers were recorded, significant differences were found between materials used, tile size and methods of deployment. Significant differences were detected in total coral settlement rates and for the two dominant taxonomic groups, acroporids and pocilloporids. Standardisation of tile materials, dimensions, and method of deployment is needed for comparison between coral and other epibiont settlement studies. However, a greater understanding of the effects of these experimental variables on settlement processes may enable retrospective comparisons between studies utilising a range of materials and methods.
13. Performance et caracterisation a l'arrachement des tiges en FRP de carbone utilisees pour renforcement au cisaillement par la methode ETS
The rehabilitation and strengthening concrete structures in shear using composite materials such as externally bonded (EB) or near surface mounted rebar (NSMR) are well established techniques. However, debonding of these strengthening materials is still present and constitute the principal cause of shear failure of beams strengthened with composite materials. A new method called ETS (Embedded Through Section) was recently developed in order to avoid premature failures due to debonding of composite materials. The objective of this study is to highlight the importance and influence of important parameters on the behavior of CFRP bars anchorages subjected to pullout forces. These parameters are: concrete strength, anchorage length of CFRP bars, hole diameter in concrete, diameter of the bar and CFRP surface type (smooth versus sanded). Understanding the influence of these parameters on the relationship between the pullout force and the slip is paramount. This allows an accurate description of the behavior of all elements that contribute to the resistance of the CFRP bars pullout. A series of 25 specimens were subjected to pullout tests. The impact of these parameters on the pullout performance of CFRP rods is summarized in terms of failure mode, ultimate tensile strength and loading force slip relationship. The results of these investigations show that using the ETS method, failure of the anchors can be avoided by providing adequate anchorage length and concrete strength. The method provides greater confinement and thus leads to a substantial improvement in the performance of anchors. As a result, designers will be able to avoid failures that are due to debonding of anchors using thereby the full capabilities of reinforced beams strengthened in shear with EB FRP. Keywords: ETS method, shear, strengthening, anchor, slip, FRP, NSM.
14. A Location Method Using Sensor Arrays for Continuous Gas Leakage in Integrally Stiffened Plates Based on the Acoustic Characteristics of the Stiffener
PubMed Central
Bian, Xu; Li, Yibo; Feng, Hao; Wang, Jiaqiang; Qi, Lei; Jin, Shijiu
2015-01-01
This paper proposes a continuous leakage location method based on the ultrasonic array sensor, which is specific to continuous gas leakage in a pressure container with an integral stiffener. This method collects the ultrasonic signals generated from the leakage hole through the piezoelectric ultrasonic sensor array, and analyzes the space-time correlation of every collected signal in the array. Meanwhile, it combines with the method of frequency compensation and superposition in time domain (SITD), based on the acoustic characteristics of the stiffener, to obtain a high-accuracy location result on the stiffener wall. According to the experimental results, the method successfully solves the orientation problem concerning continuous ultrasonic signals generated from leakage sources, and acquires high accuracy location information on the leakage source using a combination of multiple sets of orienting results. The mean value of location absolute error is 13.51 mm on the one-square-meter plate with an integral stiffener (4 mm width; 20 mm height; 197 mm spacing), and the maximum location absolute error is generally within a ±25 mm interval. PMID:26404316
15. Tomographic Imaging of the Cascadia Subduction Zone and Juan de Fuca Plate System: Improved Methods Eliminate Artifacts and Reveal New Structures
Bodmer, M.; Toomey, D. R.; Hooft, E. E. E.; Bezada, M.; Schmandt, B.; Byrnes, J. S.
2017-12-01
Amphibious studies of subduction zones promise advances in understanding links between incoming plate structure, the subducting slab, and the upper mantle beneath the slab. However, joint onshore/offshore imaging is challenging due to contrasts between continental and oceanic structure. We present P-wave teleseismic tomography results for the Cascadia subduction zone (CSZ) that utilize existing western US datasets, amphibious seismic data from the Cascadia Initiative, and tomographic algorithms that permit 3D starting models, nonlinear ray tracing, and finite frequency kernels. Relative delay times show systematic onshore/offshore trends, which we attribute to structure in the upper 50 km. Shore-crossing CSZ seismic refraction models predict relative delays >1s, with equal contributions from elevation and crustal thickness. We use synthetic data to test methods of accounting for such shallow structure. Synthetic tests using only station static terms produce margin-wide, sub-slab low-velocity artifacts. Using a more realistic a priori 3D model for the upper 50 km better reproduces known input structures. To invert the observed delays, we use data-constrained starting models of the CSZ. Our preferred models utilize regional surface wave studies to construct a starting model, directly account for elevation, and use 3D nonlinear ray tracing. We image well-documented CSZ features, including the subducted slab down to 350 km, along strike slab variations below 150 km, and deep slab fragmentation. Inclusion of offshore data improves resolution of the sub-slab mantle, where we resolve localized low-velocity anomalies near the edges of the CSZ (beneath the Klamath and Olympic mountains). Our new imaging and resolution tests indicate that previously reported margin-wide, sub-slab low-velocity asthenospheric anomalies are an imaging artifact. Offshore, we observe low-velocity anomalies beneath the Gorda plate consistent with regional deformation and broad upwelling resulting
16. Optimisation d'un systeme d'antigivrage a air chaud pour aile d'avion basee sur la methode du krigeage dual
Hannat, Ridha
The aim of this thesis is to apply a new methodology of optimization based on the dual kriging method to a hot air anti-icing system for airplanes wings. The anti-icing system consists of a piccolo tube placed along the span of the wing, in the leading edge area. The hot air is injected through small nozzles and impact on the inner wall of the wing. The objective function targeted by the optimization is the effectiveness of the heat transfer of the anti-icing system. This heat transfer effectiveness is regarded as being the ratio of the wing inner wall heat flux and the sum of all the nozzles heat flows of the anti-icing system. The methodology adopted to optimize an anti-icing system consists of three steps. The first step is to build a database according to the Box-Behnken design of experiment. The objective function is then modeled by the dual kriging method and finally the SQP optimization method is applied. One of the advantages of the dual kriging is that the model passes exactly through all measurement points, but it can also take into account the numerical errors and deviates from these points. Moreover, the kriged model can be updated at each new numerical simulation. These features of the dual kriging seem to give a good tool to build the response surfaces necessary for the anti-icing system optimization. The first chapter presents a literature review and the optimization problem related to the antiicing system. Chapters two, three and four present the three articles submitted. Chapter two is devoted to the validation of CFD codes used to perform the numerical simulations of an anti-icing system and to compute the conjugate heat transfer (CHT). The CHT is calculated by taking into account the external flow around the airfoil, the internal flow in the anti-icing system, and the conduction in the wing. The heat transfer coefficient at the external skin of the airfoil is almost the same if the external flow is taken into account or no. Therefore, only the
17. An Implementation Method of the Fractional-Order PID Control System Considering the Memory Constraint and its Application to the Temperature Control of Heat Plate
Sasano, Koji; Okajima, Hiroshi; Matsunaga, Nobutomo
Recently, the fractional order PID (FO-PID) control, which is the extension of the PID control, has been focused on. Even though the FO-PID requires the high-order filter, it is difficult to realize the high-order filter due to the memory limitation of digital computer. For implementation of FO-PID, approximation of the fractional integrator and differentiator are required. Short memory principle (SMP) is one of the effective approximation methods. However, there is a disadvantage that the approximated filter with SMP cannot eliminate the steady-state error. For this problem, we introduce the distributed implementation of the integrator and the dynamic quantizer to make the efficient use of permissible memory. The objective of this study is to clarify how to implement the accurate FO-PID with limited memories. In this paper, we propose the implementation method of FO-PID with memory constraint using dynamic quantizer. And the trade off between approximation of fractional elements and quantized data size are examined so as to close to the ideal FO-PID responses. The effectiveness of proposed method is evaluated by numerical example and experiment in the temperature control of heat plate.
18. The band gap properties of the three-component semi-infinite plate-like LRPC by using PWE/FE method
Qian, Denghui; Wang, Jianchun
2018-06-01
This paper applies coupled plane wave expansion and finite element (PWE/FE) method to calculate the band structure of the proposed three-component semi-infinite plate-like locally resonant phononic crystal (LRPC). In order to verify the accuracy of the result, the band structure calculated by PWE/FE method is compared to that calculated by the traditional finite element (FE) method, and the frequency range of the band gap in the band structure is compared to that of the attenuation in the transmission power spectrum. Numerical results and further analysis demonstrate that a band gap is opened by the coupling between the dominant vibrations of the rubber layer and the matrix modes. In addition, the influences of the geometry parameters on the band gap are studied and understood with the help of the simple “base-spring-mass” model, the influence of the viscidity of rubber layer on the band gap is also investigated.
19. A combined disc method with resazurin agar plate assay for early phenotypic screening of KPC, MBL and OXA-48 carbapenemases among Enterobacteriaceae.
PubMed
Teethaisong, Y; Eumkeb, G; Nakouti, I; Evans, K; Hobbs, G
2016-08-01
To validate a combined disc method along with resazurin chromogenic agar for early screening and differentiation of Klebsiella pneumoniae carbapenemase, metallo-β-lactamase and OXA-48 carbapenemase-producing Enterobacteriaceae. The combined disc test comprising of meropenem alone and with EDTA, phenylboronic acid or both EDTA and phenylboronic acid, and temocillin alone were evaluated with the resazurin chromogenic agar plate assay against a total of 86 molecularly confirmed Enterobacteriaceae clinical isolates (11 metallo-β-lactamases, eight Kl. pneumoniae carbapenemases, 11 OXA-48, 32 AmpC and 15 extended-spectrum-β-lactamase producers and nine co-producers of extended-spectrum-β-lactamase and AmpC). The inhibition zone diameters were measured and interpreted at 7 h for the presence of carbapenemase. All carbapenemase producers were phenotypically distinguished by this assay with 100% sensitivity and specificity. This early phenotypic method is very simple, inexpensive, and reliable in the detection and differentiation of carbapenemase-producing Enterobacteriaceae. It could be exploited in any microbiological laboratory for diagnosis of these recalcitrant bacteria. This assay poses excellent performance in discrimination of Kl. pneumoniae carbapenemase, metallo-β-lactamase and OXA-48 carbapenemases within 7 h, which is much faster than conventional disc diffusion methods. The rapid detection could help clinicians screen patients, control infection and provide epidemiological surveillance. © 2016 The Society for Applied Microbiology.
20. Sputtering and ion plating
NASA Technical Reports Server (NTRS)
1972-01-01
The proceedings of a conference on sputtering and ion plating are presented. Subjects discussed are: (1) concepts and applications of ion plating, (2) sputtering for deposition of solid film lubricants, (3) commercial ion plating equipment, (4) industrial potential for ion plating and sputtering, and (5) fundamentals of RF and DC sputtering.
1. Practical automatic Arabic license plate recognition system
2011-02-01
2. Microstructural and Mechanical Properties of Welded High Strength Steel Plate Using SMAW and SAW Method for LPG Storage Tanks
Winarto, Winarto; Riastuti, Rini; Kumeidi, Nur
2018-03-01
Indonesian government policy to convert energy consumption for domestic household from kerosene to liquefied petroleum gas (LPG) may lead to the increasing demand for LPG storage tank. LPG storage tank with a large capacity generally used the HSLA steel material of ASTM A516 Grade 70 joined by SMAW or combination between SMAW and SAW method. The heat input can affect the microstructure and mechanical properties of the weld area. The input heat is proportional to the welding current and the arc voltage, but inversely proportional to its welding speed. The result shows that the combination of SMAW-SAW process yield the lower hardness in the HAZ and the fusion zone compared to the singe SMAW process. PWHT mainly applied to reduce residual stress of welded joint. The result shows that PWHT can reduce the hardness in the HAZ and the fusion zone in comparing with the singe SMAW process. The microstructure of weld joint shows a coarser structure in the combined welding process (SMAW-SAW) comparing with the single welding process (SMAW).
3. A new microtitre plate screening method for evaluating the viability of aerobic respiring bacteria in high surface biofilms.
PubMed
Pérez, L M; Alvarez, B L; Codony, F; Fittipaldi, M; Adrados, B; Peñuela, G; Morató, J
2010-09-01
It is difficult to determine the effects of bactericidal compounds against bacteria in a biofilm because classical procedures for determining cell viability require several working days, multiple complicated steps and are frequently only applicable to cells in suspension. We attempt to develop a compact, inexpensive and versatile system to measure directly the extent of biofilm formation from water systems and to determine the viability of respiring bacteria in high surface biofilms. It has been reported that the reduction of tetrazolium sodium salts, such as XTT (sodium 3,3'-[1-[(phenylamino)carbonyl]-3,4-tetrazolium]Bis(4-methoxy)-6-nitro)benzene sulfonic acid hydrate), during active bacterial metabolism can be incorporated into a colorimetric method for quantifying cell viability. XTT is reduced to a soluble formazan compound during bacterial aerobic metabolism such that the amount of formazan generated is proportional to the bacterial biomass. We show here, for the first time, that this colorimetric approach can be used to determine the metabolic activity of adherent aerobic bacteria in a biofilm as a measure of cell viability. This technique has been used to estimate viability and proliferation of bacteria in suspension, but this is the first application to microbial communities in a real undisturbed biofilm. This simple new system can be used to evaluate the complex biofilm community without separating the bacteria from their support. Thus, the results obtained by this practice may be more representative of the circumstances in a natural system, opening the possibility to multiple potential applications.
4. Interlaminar stress analysis of dropped-ply laminated plates and shells by a mixed method. Ph.D. Thesis
NASA Technical Reports Server (NTRS)
Harrison, Peter N.; Johnson, Eric R.; Starnes, James H., Jr.
1994-01-01
A mixed method of approximation based on Reissner's variational principle is developed for the linear analysis of interlaminar stresses in laminated composites, with special interest in laminates that contain terminated internal plies (dropped-ply laminates). Two models are derived, one for problems of generalized plane deformation and the other for the axisymmetric response of shells of revolution. A layerwise approach is taken in which the stress field is assumed with an explicit dependence on the thickness coordinate in each layer. The dependence of the stress field on the thickness coordinate is determined such that the three-dimensional equilibrium equations are satisfied by the approximation. The solution domain is reduced to one dimension by integration through the thickness. Continuity of tractions and displacements between layers is imposed. The governing two-point boundary value problem is composed of a system of both differential and algebraic equations (DAE's) and their associated boundary conditions. Careful evaluation of the system of DAE's was required to arrive at a form that allowed application of a one-step finite difference approximation. A two-stage Gauss implicit Runge-Kutta finite difference scheme was used for the solution because of its relatively high degree of accuracy. Patch tests of the two models revealed problems with solution accuracy for the axisymmetric model of a cylindrical shell loaded by internal pressure. Parametric studies of dropped-ply laminate characteristics and their influence on the interlaminar stresses were performed using the generalized plane deformation model. Eccentricity of the middle surface of the laminate through the ply drop-off was found to have a minimal effect on the interlaminar stresses under longitudinal compression, transverse tension, and in-plane shear. A second study found the stiffness change across the ply termination to have a much greater influence on the interlaminar stresses.
5. An enhanced computational method for age-at-death estimation based on the pubic symphysis using 3D laser scans and thin plate splines.
PubMed
Stoyanova, Detelina; Algee-Hewitt, Bridget F B; Slice, Dennis E
2015-11-01
The pubic symphysis is frequently used to estimate age-at-death from the adult skeleton. Assessment methods require the visual comparison of the bone morphology against age-informative characteristics that represent a series of phases. Age-at-death is then estimated from the age-range previously associated with the chosen phase. While easily executed, the "morphoscopic" process of feature-scoring and bone-to-phase-matching is known to be subjective. Studies of method and practitioner error demonstrate a need for alternative tools to quantify age-progressive change in the pubic symphysis. This article proposes a more objective, quantitative method that analyzes three-dimensional (3D) surface scans of the pubic symphysis using a thin plate spline algorithm (TPS). This algorithm models the bending of a flat plane to approximately match the surface of the bone and minimizes the bending energy required for this transformation. Known age-at-death and bending energy were used to construct a linear model to predict age from observed bending energy. This approach is tested with scans from 44 documented white male skeletons and 12 casts. The results of the surface analysis show a significant association (regression p-value = 0.0002 and coefficient of determination = 0.2270) between the minimum bending energy and age-at-death, with a root mean square error of ≈19 years. This TPS method yields estimates comparable to established methods but offers a fully integrated, objective and quantitative framework of analysis and has potential for use in archaeological and forensic casework. © 2015 Wiley Periodicals, Inc.
6. Comparison of PrestoBlue® and plating method to evaluate antimicrobial activity of ascorbic acid, boric acid and curcumin in an in vitro gastrointestinal model.
PubMed
Hernandez-Patlan, D; Solis-Cruz, B; Méndez-Albores, A; Latorre, J D; Hernandez-Velasco, X; Tellez, G; López-Arellano, R
2018-02-01
To compare the conventional plating method vs a fluorometric method using PrestoBlue ® as a dye by determining the antimicrobial activity of two organic acids and curcumin (CUR) against Salmonella Enteritidis in an avian in vitro digestion model that simulates the crop, proventriculus and intestine. A concentration of 10 8 CFU per ml of S. Enteritidis was exposed to groups with different rates of ascorbic acid (AA), boric acid (BA) and CUR. Significant differences were observed when the means of the treatments were compared with the controls in the compartments that simulate the crop and intestine (P < 0·05). Ascorbic acid alone and high rates of AA in the mixtures were the most efficient treatments in the crop compartment. However, in the intestinal compartment BA alone and at different rates in the mixture BA-CUR (1 : 1) were the best treatments to decrease the concentration of S. Enteritidis. The results of this study suggest that there could be an antagonistic bactericidal effect between AA and CUR and AA and BA as well as a synergistic bactericidal effect between BA and CUR. These findings may contribute to the development of a formulation with microencapsulated compounds to liberate them in different compartments to combat S. Enteritidis infections in broiler chickens. © 2017 The Society for Applied Microbiology.
7. Surface characteristic of chemically converted graphene coated low carbon steel by electro spray coating method for polymer electrolyte membrane fuel cell bipolar plate.
PubMed
Kim, Jungsoo; Kim, Yang Do; Nam, Dae Geun
2013-05-01
Graphene was coated on low carbon steel (SS400) by electro spray coating method to improve its properties of corrosion resistance and contact resistance. Exfoliated graphite was made of the graphite by chemical treatment (Chemically Converted Graphene, CCG). CCG is distributed using dispersing agent, and low carbon steel was coated with diffuse graphene solution by electro spray coating method. The structure of the CCG was analyzed using XRD and the coating layer of surface was analyzed using SEM. Analysis showed that multi-layered graphite structure was destroyed and it was transformed in to fine layers graphene structure. And the result of SEM analysis on the surface and the cross section, graphene layer was uniformly formed with 3-5 microm thickness on the surface of substrate. Corrosion resistance test was applied in the corrosive solution which is similar to the polymer electrolyte membrane fuel cell (PEMFC) stack inside. And interfacial contact resistance (ICR) test was measured to simulate the internal operating conditions of PEMFC stack. As a result of measuring corrosion resistance and contact resistance, it could be confirmed that low carbon steel coated with CCG was revealed to be more effective in terms of its applicability as PEMFC bipolar plate.
8. Shuttle plate braiding machine
NASA Technical Reports Server (NTRS)
Huey, Jr., Cecil O. (Inventor)
1994-01-01
A method and apparatus for moving yarn in a selected pattern to form a braided article. The apparatus includes a segmented grid of stationary support elements and a plurality of shuttles configured to carry yarn. The shuttles are supported for movement on the grid assembly and each shuttle includes a retractable plunger for engaging a reciprocating shuttle plate that moves below the grid assembly. Such engagement at selected times causes the shuttles to move about the grid assembly in a selected pattern to form a braided article of a particular geometry.
9. Deformation of a plate with periodically changing parameters
Naumova, Natalia V.; Ivanov, Denis; Voloshinova, Tatiana
2018-05-01
Deformation of reinforced square plate under external pressure is considered. The averaged fourth-order partial differential equation for the plate deflection w is obtained. The new mathematical model of the plate is offered. Asymptotic averaging and Finite Elements Method (ANSYS) are used to get the values of normal deflections of the plate surface. The comparison of numerical and asymptotic results is performed.
10. Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.
PubMed
2014-01-01
The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates. Copyright © 2013 Elsevier B.V. All rights reserved.
11. Potentiodynamic studies of Ni-P-TiO2 nano-composited coating on the mild steel deposited by electroless plating method
Uttam, Vibha; Duchaniya, R. K.
2016-05-01
Now a days, corrosion studies are important for reducing the wastage of metals. The importance of corrosion studies is two folds i.e. first is economic, including the reduction of material losses resulting from the wasting away or sudden failure of materials and second is conservation Electroless process is an autocatalytic reduction method in which metallic ions are reduced in the solution. Nanocomposite coatings of Ni-P-TiO2 on mild steel are deposited by varying volume of TiO2 nano-powder by electroless method from Ni-P plating bath containing Nickel Sulphate as a source of nickel ions, sodium hypophosphite as the reducing agent, lactic acid as a complexing agents and TiO2 nano powder. Electroless Ni-P-TiO2 coating have been widely used in the chemical process industries, mechanical industries, electronic industries and chloroalkali industries due to their excellent corrosion with mechanical properties. In the present work, deposition of Ni-P alloy coating and Ni-P-TiO2 nanocomposited coatings were done on the mild steel and corrosion properties were studied with Potentio-dynamic polarization measurements method in 3.5 wt% sodium chloride solution. It showed in the experiments that Ni-P-TiO2 nanocomposited coating has better corrosion resistance as comparedthan Ni-P alloy coating. Morphological studies were done by field emission scanning electron microscopy (FESEM), energy-dispersive analysis of X-ray (EDAX) and X-ray diffraction (XRD). These studies confirmed the deposition of Ni-P alloy coating and Ni-P-TiO2 nanocomposited coating.
12. Potentiodynamic studies of Ni-P-TiO{sub 2} nano-composited coating on the mild steel deposited by electroless plating method
SciTech Connect
Uttam, Vibha, E-mail: vibhauttam74@gmail.com; Duchaniya, R. K., E-mail: rkduchaniya.meta@mnit.ac.in
2016-05-06
Now a days, corrosion studies are important for reducing the wastage of metals. The importance of corrosion studies is two folds i.e. first is economic, including the reduction of material losses resulting from the wasting away or sudden failure of materials and second is conservation Electroless process is an autocatalytic reduction method in which metallic ions are reduced in the solution. Nanocomposite coatings of Ni-P-TiO{sub 2} on mild steel are deposited by varying volume of TiO{sub 2} nano-powder by electroless method from Ni-P plating bath containing Nickel Sulphate as a source of nickel ions, sodium hypophosphite as the reducing agent,more » lactic acid as a complexing agents and TiO{sub 2} nano powder. Electroless Ni-P-TiO{sub 2} coating have been widely used in the chemical process industries, mechanical industries, electronic industries and chloroalkali industries due to their excellent corrosion with mechanical properties. In the present work, deposition of Ni-P alloy coating and Ni-P-TiO{sub 2} nanocomposited coatings were done on the mild steel and corrosion properties were studied with Potentio-dynamic polarization measurements method in 3.5 wt% sodium chloride solution. It showed in the experiments that Ni-P-TiO{sub 2} nanocomposited coating has better corrosion resistance as comparedthan Ni-P alloy coating. Morphological studies were done by field emission scanning electron microscopy (FESEM), energy–dispersive analysis of X-ray (EDAX) and X-ray diffraction (XRD). These studies confirmed the deposition of Ni-P alloy coating and Ni-P-TiO{sub 2} nanocomposited coating.« less
13. Development and validation of a method for fipronil residue determination in ovine plasma using 96-well plate solid-phase extraction and gas chromatography-tandem mass spectrometry.
PubMed
Bichon, E; Richard, C A; Le Bizec, B
2008-08-01
Fipronil, a phenylpyrazole insecticide introduced for pest control on a broad range of crops, undergoes a reinforcement of the regulation within the European Union (2007/52/EC directive) due to its potential effects on environment and human health. In order to assess the plasmatic concentrations of fipronil residues (sulfone, sulfide, fipronil, desulfinyl and amide) in ovine, a methodology based on gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was developed and validated according to the European standard (2002/657/EC). The proposed method allows a large number of samples to be treated concurrently (n=80) using a reduced sample amounts (0.2 mL), and consents to reach a level of quantification of 0.1 pg microL(-1). The sample preparation consisted of a single solid-phase extraction (SPE) purification on a 96-well plate filled with a styrene-divinyl-benzene phase. Linearity was demonstrated all along the investigated range of concentrations, i.e. from 0.25 to 2000 pg microL(-1), with coefficient of determination (R(2)) from 0.977 to 0.994, depending on target analytes. Calculated decision limit (CCalpha) and detection capability (CCbeta) for fipronil, sulfone and sulphide were in the range 0.05-0.16 and 0.28-0.73 pg microL(-1) respectively.
14. An Automated Method for High-Throughput Screening of Arabidopsis Rosette Growth in Multi-Well Plates and Its Validation in Stress Conditions.
PubMed
De Diego, Nuria; Fürst, Tomáš; Humplík, Jan F; Ugena, Lydia; Podlešáková, Kateřina; Spíchal, Lukáš
2017-01-01
High-throughput plant phenotyping platforms provide new possibilities for automated, fast scoring of several plant growth and development traits, followed over time using non-invasive sensors. Using Arabidops is as a model offers important advantages for high-throughput screening with the opportunity to extrapolate the results obtained to other crops of commercial interest. In this study we describe the development of a highly reproducible high-throughput Arabidopsis in vitro bioassay established using our OloPhen platform, suitable for analysis of rosette growth in multi-well plates. This method was successfully validated on example of multivariate analysis of Arabidopsis rosette growth in different salt concentrations and the interaction with varying nutritional composition of the growth medium. Several traits such as changes in the rosette area, relative growth rate, survival rate and homogeneity of the population are scored using fully automated RGB imaging and subsequent image analysis. The assay can be used for fast screening of the biological activity of chemical libraries, phenotypes of transgenic or recombinant inbred lines, or to search for potential quantitative trait loci. It is especially valuable for selecting genotypes or growth conditions that improve plant stress tolerance.
15. Preparation and properties of plate-like titanate (PLT)/calcia-doped ceria (CDC) composites by sol-gel coating method.
PubMed
Liu, Xiangwen; Liu, Jingxiao; Dong, Xiaoli; Yin, Shu; Sato, Tsugio
2009-08-01
In order to obtain UV-shielding materials with good comfort, higher safety and effective UV-shielding ability, lepidocrocite type plate-like titanate (K(0.8)Li(0.27)Ti(1.73)O(4), donated as: PLT)/calcia-doped ceria (donated as: CDC) composites were synthesized by a sol-gel method. After dissolving Ce(NO(3))(3).6H(2)O and Ca(NO(3))(2).4H(2)O into absolute ethanol at 40 degrees C, glacial acetic acid (HAc) and PLT particles dispersed into absolute ethanol were added. Then, the solution was heated at 60 degrees C to get gel-like substance. This gel was dried in a vacuum oven at 333 K for 5 h, and then, the product was collected and ground in an agate mortar followed by calcination at 1073 K for 2 h to form PLT/CDC composites. By optimization, 20 mass% of CDC was coated by one operation. PLT/CDC composites with higher CDC content were obtained by repeating the coating process. The morphology, catalytic activity for the oxidation of organic material, UV-shielding ability and dynamic friction coefficient of as-obtained PLT/CDC composites were characterized. As a result, broad-spectrum UV-shielding composite materials with good comfort and low oxidation catalytic activity were successfully synthesized.
16. Comparison of an automated Most Probable Number (MPN) technique to traditional plating methods for estimating populations of total aerobes, coliforms and E. coli associated with freshly processed broiler chickens
USDA-ARS?s Scientific Manuscript database
Recently, an instrument (TEMPOTM) has been developed to automate the Most Probable Number (MPN) technique and reduce the effort required to estimate some bacterial populations. We compared the automated MPN technique to traditional microbiological plating methods or PetrifilmTM for estimating the t...
17. New Method for Accurate Calibration of Micro-Channel Plate based Detection Systems and its use in the Fast Plasma Investigation of NASA's Magnetospheric MultiScale Mission
Gliese, U.; Avanov, L. A.; Barrie, A.; Kujawski, J. T.; Mariano, A. J.; Tucker, C. J.; Chornay, D. J.; Cao, N. T.; Zeuch, M.; Pollock, C. J.; Jacques, A. D.
2013-12-01
The Fast Plasma Investigation (FPI) of the NASA Magnetospheric MultiScale (MMS) mission employs 16 Dual Electron Spectrometers (DESs) and 16 Dual Ion Spectrometers (DISs) with 4 of each type on each of 4 spacecraft to enable fast (30ms for electrons; 150ms for ions) and spatially differentiated measurements of full the 3D particle velocity distributions. This approach presents a new and challenging aspect to the calibration and operation of these instruments on ground and in flight. The response uniformity and reliability of their calibration and the approach to handling any temporal evolution of these calibrated characteristics all assume enhanced importance in this application, where we attempt to understand the meaning of particle distributions within the ion and electron diffusion regions. Traditionally, the micro-channel plate (MCP) based detection systems for electrostatic particle spectrometers have been calibrated by setting a fixed detection threshold and, subsequently, measuring a detection system count rate plateau curve to determine the MCP voltage that ensures the count rate has reached a constant value independent of further variation in the MCP voltage. This is achieved when most of the MCP pulse height distribution (PHD) is located at higher values (larger pulses) than the detection amplifier threshold. This method is adequate in single-channel detection systems and in multi-channel detection systems with very low crosstalk between channels. However, in dense multi-channel systems, it can be inadequate. Furthermore, it fails to fully and individually characterize each of the fundamental parameters of the detection system. We present a new detection system calibration method that enables accurate and repeatable measurement and calibration of MCP gain, MCP efficiency, signal loss due to variation in gain and efficiency, crosstalk from effects both above and below the MCP, noise margin, and stability margin in one single measurement. The fundamental
18. Portable Plating System
NASA Technical Reports Server (NTRS)
Flores, R.
1984-01-01
Plating system mounted on portable cart includes 30-gallon (23.5 liter) electrolyte tank, filler pump, heaters, replenishing anodes, plating rectifiers and tank rectifier to continously remove contaminants.
19. Williamson Polishing & Plating Site
EPA Pesticide Factsheets
Williamson Polishing & Plating Co. Inc. was a plating shop located in the Martindale-Brightwood neighborhood of Indianapolis. The facility conducted job shop polishing and electroplating services. The vacant site contains a 14,651-square-foot building.
20. Accelerated plate tectonics.
PubMed
Anderson, D L
1975-03-21
The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.
1. High speed thin plate fatigue crack monitor
NASA Technical Reports Server (NTRS)
Wincheski, Buzz A. (Inventor); Heyman, Joseph S. (Inventor); Namkung, Min (Inventor); Fulton, James P. (Inventor)
1996-01-01
A device and method are provided which non-destructively detect crack length and crack geometry in thin metallic plates. A non-contacting vibration apparatus produces resonant vibrations without introducing extraneous noise. Resulting resonant vibration shifts in cracked plates are correlated to known crack length in plates with similar resonant vibration shifts. In addition, acoustic emissions of cracks at resonance frequencies are correlated to acoustic emissions from known crack geometries.
2. Angular shear plate
DOEpatents
Ruda, Mitchell C [Tucson, AZ; Greynolds, Alan W [Tucson, AZ; Stuhlinger, Tilman W [Tucson, AZ
2009-07-14
One or more disc-shaped angular shear plates each include a region thereon having a thickness that varies with a nonlinear function. For the case of two such shear plates, they are positioned in a facing relationship and rotated relative to each other. Light passing through the variable thickness regions in the angular plates is refracted. By properly timing the relative rotation of the plates and by the use of an appropriate polynomial function for the thickness of the shear plate, light passing therethrough can be focused at variable positions.
3. An improved plating process
NASA Technical Reports Server (NTRS)
1994-01-01
An alternative to the immersion process for the electrodeposition of chromium from aqueous solutions on the inside diameter (ID) of long tubes is described. The Vessel Plating Process eliminates the need for deep processing tanks, large volumes of solutions, and associated safety and environmental concerns. Vessel Plating allows the process to be monitored and controlled by computer thus increasing reliability, flexibility and quality. Elimination of the trivalent chromium accumulation normally associated with ID plating is intrinsic to the Vessel Plating Process. The construction and operation of a prototype Vessel Plating Facility with emphasis on materials of construction, engineered and operational safety and a unique system for rinse water recovery are described.
4. Paper microzone plates.
PubMed
Carrilho, Emanuel; Phillips, Scott T; Vella, Sarah J; Martinez, Andres W; Whitesides, George M
2009-08-01
This paper describes 96- and 384-microzone plates fabricated in paper as alternatives to conventional multiwell plates fabricated in molded polymers. Paper-based plates are functionally related to plastic well plates, but they offer new capabilities. For example, paper-microzone plates are thin (approximately 180 microm), require small volumes of sample (5 microL per zone), and can be manufactured from inexpensive materials (0.05 per plate). The paper-based plates are fabricated by patterning sheets of paper, using photolithography, into hydrophilic zones surrounded by hydrophobic polymeric barriers. This photolithography used an inexpensive formulation photoresist that allows rapid (approximately 15 min) prototyping of paper-based plates. These plates are compatible with conventional microplate readers for quantitative absorbance and fluorescence measurements. The limit of detection per zone loaded for fluorescence was 125 fmol for fluorescein isothiocyanate-labeled bovine serum albumin, and this level corresponds to 0.02 the quantity of analyte per well used to achieve comparable signal-to-noise in a 96-well plastic plate (using a solution of 25 nM labeled protein). The limits of detection for absorbance on paper was approximately 50 pmol per zone for both Coomassie Brilliant Blue and Amaranth dyes; these values were 0.4 that required for the plastic plate. Demonstration of quantitative colorimetric correlations using a scanner or camera to image the zones and to measure the intensity of color, makes it possible to conduct assays without a microplate reader. 5. A cellular automaton method to simulate the microstructure and evolution of low-enriched uranium (LEU) U-Mo/Al dispersion type fuel plates NASA Astrophysics Data System (ADS) Drera, Saleem S.; Hofman, Gerard L.; Kee, Robert J.; King, Jeffrey C. 2014-10-01 Low-enriched uranium (LEU) fuel plates for high power materials test reactors (MTR) are composed of nominally spherical uranium-molybdenum (U-Mo) particles within an aluminum matrix. Fresh U-Mo particles typically range between 10 and 100 μm in diameter, with particle volume fractions up to 50%. As the fuel ages, reaction-diffusion processes cause the formation and growth of interaction layers that surround the fuel particles. The growth rate depends upon the temperature and radiation environment. The cellular automaton algorithm described in this paper can synthesize realistic random fuel-particle structures and simulate the growth of the intermetallic interaction layers. Examples in the present paper pack approximately 1000 particles into three-dimensional rectangular fuel structures that are approximately 1 mm on each side. The computational approach is designed to yield synthetic microstructures consistent with images from actual fuel plates and is validated by comparison with empirical data on actual fuel plates. 6. Multicolor printing plate joining NASA Technical Reports Server (NTRS) Waters, W. J. (Inventor) 1984-01-01 An upper plate having ink flow channels and a lower plate having a multicolored pattern are joined. The joining is accomplished without clogging any ink flow paths. A pattern having different colored parts and apertures is formed in a lower plate. Ink flow channels each having respective ink input ports are formed in an upper plate. The ink flow channels are coated with solder mask and the bottom of the upper plate is then coated with solder. The upper and lower plates are pressed together at from 2 to 5 psi and heated to a temperature of from 295 F to 750 F or enough to melt the solder. After the plates have cooled and the pressure is released, the solder mask is removed from the interior passageways by means of a liquid solvent. 7. Treatment of reducible unstable fractures of the distal radius: randomized clinical study comparing the locked volar plate and external fixator methods: study protocol. PubMed Raduan Neto, Jorge; de Moraes, Vinicius Ynoe; Gomes Dos Santos, João B; Faloppa, Flávio; Belloti, João Carlos 2014-03-05 Various treatments are available for reducible unstable fractures of the distal radius, such as closed reduction combined with fixation by external fixator (EF), and rigid internal fixation using a locked volar plate (VP). Although there are studies comparing these methods, there is no conclusive evidence indicating which treatment is best. The hypothesis of this study is that surgical treatment with a VP is more effective than EF from the standpoint of functional outcome (patient-reported). The study is randomized clinical trial with parallel groups and a blinded evaluator and involves the surgical interventions EF and VP. Patients will be randomly assigned (assignment ratio 1:1) using sealed opaque envelopes. This trial will include consecutive adult patients with an acute (up to 15 days) displaced, unstable fracture of the distal end of the radius of type A2, A3, C1, C2 or C3 by the Arbeitsgemeinschaft für Osteosynthesefragen-Association for the Study of Internal Fixation classification and type II or type III by the IDEAL32 classification, without previous surgical treatments of the wrist. The surgical intervention assigned will be performed by three surgical specialists familiar with the techniques described. Evaluations will be performed at 2, and 8 weeks, 3, 6 and 12 months, with the primary outcomes being measured by the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and measurement of pain (Visual Analog Pain Scale and digital algometer). Secondary outcomes will include radiographic parameters, objective functional evaluation (goniometry and dynamometry), and the rate of complications and method failure according to the intention-to-treat principle. Final postoperative evaluations (6 and 12 months) will be performed by independent blinded evaluators. For the Student's t-test, a difference of 10 points in the DASH score, with a 95% confidence interval, a statistical power of 80%, and 20% sampling error results in 36 patients per group 8. Improved nickel plating of Inconel X-750 NASA Technical Reports Server (NTRS) Farmer, M. E.; Feeney, J. E.; Kuster, C. A. 1969-01-01 Electroplating technique with acid pickling provides a method of applying nickel plating on Inconel X-750 tubing to serve as a wetting agent during brazing. Low-stress nickel-plating bath contains no organic wetting agents that cause the nickel to blister at high temperatures. 9. Anterior inferior plating versus superior plating for clavicle fracture: a meta-analysis. PubMed Ai, Jie; Kan, Shun-Li; Li, Hai-Liang; Xu, Hong; Liu, Yang; Ning, Guang-Zhi; Feng, Shi-Qing 2017-04-18 The position of plate fixation for clavicle fracture remains controversial. Our objective was to perform a comprehensive review of the literature and quantify the surgical parameters and clinical indexes between the anterior inferior plating and superior plating for clavicle fracture. PubMed, EMBASE, and the Cochrane Library were searched for randomized and non-randomized studies that compared the anterior inferior plating with the superior plating for clavicle fracture. The relative risk or standardized mean difference with 95% confidence interval was calculated using either a fixed- or random-effects model. Four randomized controlled trials and eight observational studies were identified to compare the surgical parameters and clinical indexes. For the surgical parameters, the anterior inferior plating group was better than the superior plating group in operation time and blood loss (P < 0.05). Furthermore, in terms of clinical indexes, the anterior inferior plating was superior to the superior plating in reducing the union time, and the two kinds of plate fixation methods were comparable in constant score, and the rate of infection, nonunion, and complications (P > 0.05). Based on the current evidence, the anterior inferior plating may reduce the blood loss, the operation and union time, but no differences were observed in constant score, and the rate of infection, nonunion, and complications between the two groups. Given that some of the studies have low quality, more randomized controlled trails with high quality should be conduct to further verify the findings. 10. GOLD PLATING PROCESS DOEpatents Seegmiller, R. 1957-08-01 An improved bath is reported for plating gold on other metals. The composition of the plating bath is as follows: Gold cyanide from about 15 to about 50 grams, potassium cyanide from about 70 to about 125 grams, and sulfonated castor oil from about 0.1 to about 10 cc. The gold plate produced from this bath is smooth, semi-hard, and nonporous. 11. CALUTRON FACE PLATE DOEpatents Brobeck, W.M. 1959-08-25 The construction of a removable cover plate for a calutron tank is described. The plate is fabricated of a rectangular frame member to which is welded a bowed or dished plate of thin steel, reinforced with transverse stiffening ribs. When the tank is placed between the poles of a magnet, the plate may be pivoted away from the tank and magnet and is adapted to support the ion separation mechanism secured to its inner side as well as the vacuum load within the tank. 12. PLATES WITH OXIDE INSERTS DOEpatents West, J.M.; Schumar, J.F. 1958-06-10 Planar-type fuel assemblies for nuclear reactors are described, particularly those comprising fuel in the oxide form such as thoria and urania. The fuel assembly consists of a plurality of parallel spaced fuel plate mennbers having their longitudinal side edges attached to two parallel supporting side plates, thereby providing coolant flow channels between the opposite faces of adjacent fuel plates. The fuel plates are comprised of a plurality of longitudinally extending tubular sections connected by web portions, the tubular sections being filled with a plurality of pellets of the fuel material and the pellets being thermally bonded to the inside of the tubular section by lead. 13. Electronic Equipment Cold Plates DTIC Science & Technology 1976-04-01 using fans or blowers to force the air through the cooling device». ^J^lJ^^i 5!°^ it ia ’«"^"o^ve. nonto«ic. nonfla—able, *nd possesses good ...Techniques GENERAL THERMAL CONTROL SYSTEMS AND THEIR REgUIREMENTS FLON DISTRIBUTION IN MANIFOLDS THE COLD PLATE IA ,! 1 3 S 12 15 33 32 32... IA .1 132 132 132 155 169 179 183 r (1) Air-Cooled Cold Plate No. (2) Air-Cooled Cold Plate No. (3) Air-cooled Cold Plate No. (4) Air-Cooled 14. Comparison between open plating versus minimally invasive plate osteosynthesis for acute displaced clavicular shaft fractures. PubMed Sohn, Hoon-Sang; Kim, Won Ju; Shon, Min Soo 2015-08-01 Current literatures describe good clinical outcomes of acute displaced fracture of clavicle treated with minimally invasive plate osteosynthesis (MIPO). But, there are little comparative data of the outcomes between open plating and MIPO techniques. We compared the outcomes of open plating and MIPO for treatment of acute displaced clavicular shaft fractures. The author performed a retrospective review on a consecutive series of patients with clavicular shaft fracture who underwent open plating or MIPO. Fourteen patients were treated with open plating with interfragmentary screw fixation, and 19 were treated with the MIPO technique without exposing a fracture site itself. A superior plating method was applied to both groups. Patient demographics, clinical outcomes using Constant score and University of California Los Angeles (UCLA) shoulder score, operation time, union rate, complications, and radiographic evaluation were evaluated. There were no statistically significant differences in the demographic data, including patient's variables (age, gender, involved side, smoking, alcohol, and diabetic status) and fracture characteristics (trauma mechanism, distribution of fracture type, presence of polytrauma, and time from trauma to surgery) between the two groups. Mean operation time was 87.5 min in open plating and 77.2 min in MIPO (p=0.129). The mean time to union was 15.7 weeks in patients who underwent open plating and 16.8 weeks in patients who underwent MIPO (p=0.427). Although there was no significant difference, nonunion developed 1 case in MIPO while none was in open plating. Four patients in open plating had skin numbness (none in MIPO, p=0.024). There was no significant difference in the Constant score and UCLA score of the two surgical methods. This study showed that both open plating with interfragmentary screw fixation (Open plating) and minimally invasive plate osteosynthesis (MIPO) are equally effective and safe treatment methods for acute displaced 15. A THUMBNAIL HISTORY OF HETEROTROPHIC PLATE COUNT (HPC) METHODOLOGY IN THE UNITED STATES EPA Science Inventory Over the past 100 years, the method of determining the number of bacteria in water, foods or other materials has been termed variously as: bacterial plate count, total plate count, total viable plate count, aerobic plate count, standard plate cound and more recently, heterotrophi... 16. Enhancements for digital imaging of gusset plate connections : fisheye and image stitching. DOT National Transportation Integrated Search 2011-09-01 This report describes techniques to convert fisheye digital images of gusset plates to perspective images (defish). It also describes methods to stitch together partial images of a gusset plate into a composite of the complete gusset plate. The conve... 17. A cellular automaton method to simulate the microstructure and evolution of low-enriched uranium (LEU) U–Mo/Al dispersion type fuel plates SciTech Connect Drera, Saleem S.; Hofman, Gerard L.; Kee, Robert J. Low-enriched uranium (LEU) fuel plates for high power materials test reactors (MTR) are composed of nominally spherical uranium-molybdenum (U-Mo) particles within an aluminum matrix. Fresh U-Mo particles typically range between 10 and 100 mu m in diameter, with particle volume fractions up to 50%. As the fuel ages, reaction-diffusion processes cause the formation and growth of interaction layers that surround the fuel particles. The growth rate depends upon the temperature and radiation environment. The cellular automaton algorithm described in this paper can synthesize realistic random fuel-particle structures and simulate the growth of the intermetallic interaction layers. Examples in the presentmore » paper pack approximately 1000 particles into three-dimensional rectangular fuel structures that are approximately 1 mm on each side. The computational approach is designed to yield synthetic microstructures consistent with images from actual fuel plates and is validated by comparison with empirical data on actual fuel plates. (C) 2014 Elsevier B.V. All rights reserved.« less 18. Plate refractive camera model and its applications NASA Astrophysics Data System (ADS) Huang, Longxiang; Zhao, Xu; Cai, Shen; Liu, Yuncai 2017-03-01 In real applications, a pinhole camera capturing objects through a planar parallel transparent plate is frequently employed. Due to the refractive effects of the plate, such an imaging system does not comply with the conventional pinhole camera model. Although the system is ubiquitous, it has not been thoroughly studied. This paper aims at presenting a simple virtual camera model, called a plate refractive camera model, which has a form similar to a pinhole camera model and can efficiently model refractions through a plate. The key idea is to employ a pixel-wise viewpoint concept to encode the refraction effects into a pixel-wise pinhole camera model. The proposed camera model realizes an efficient forward projection computation method and has some advantages in applications. First, the model can help to compute the caustic surface to represent the changes of the camera viewpoints. Second, the model has strengths in analyzing and rectifying the image caustic distortion caused by the plate refraction effects. Third, the model can be used to calibrate the camera's intrinsic parameters without removing the plate. Last but not least, the model contributes to putting forward the plate refractive triangulation methods in order to solve the plate refractive triangulation problem easily in multiviews. We verify our theory in both synthetic and real experiments. 19. Vacuum fusion bonding of glass plates DOEpatents Swierkowski, Steve P.; Davidson, James C.; Balch, Joseph W. 2001-01-01 An improved apparatus and method for vacuum fusion bonding of large, patterned glass plates. One or both glass plates are patterned with etched features such as microstructure capillaries and a vacuum pumpout moat, with one plate having at least one hole therethrough for communication with a vacuum pumpout fixture. High accuracy alignment of the plates is accomplished by a temporary clamping fixture until the start of the fusion bonding heat cycle. A complete, void-free fusion bond of seamless, full-strength quality is obtained through the plates; because the glass is heated well into its softening point and because of a large, distributed force that is developed that presses the two plates together from the difference in pressure between the furnace ambient (high pressure) and the channeling and microstructures in the plates (low pressure) due to the vacuum drawn. The apparatus and method may be used to fabricate microcapillary arrays for chemical electrophoresis; for example, any apparatus using a network of microfluidic channels embedded between plates of glass or similar moderate melting point substrates with a gradual softening point curve, or for assembly of glass-based substrates onto larger substrates, such as in flat panel display systems. 20. Vacuum fusion bonding of glass plates DOEpatents Swierkowski, Steve P.; Davidson, James C.; Balch, Joseph W. 2000-01-01 An improved apparatus and method for vacuum fusion bonding of large, patterned glass plates. One or both glass plates are patterned with etched features such as microstructure capillaries and a vacuum pumpout moat, with one plate having at least one hole therethrough for communication with a vacuum pumpout fixture. High accuracy alignment of the plates is accomplished by a temporary clamping fixture until the start of the fusion bonding heat cycle. A complete, void-free fusion bond of seamless, full-strength quality is obtained through the plates; because the glass is heated well into its softening point and because of a large, distributed force that is developed that presses the two plates together from the difference in pressure between the furnace ambient (high pressure) and the channeling and microstructures in the plates (low pressure) due to the vacuum drawn. The apparatus and method may be used to fabricate microcapillary arrays for chemical electrophoresis; for example, any apparatus using a network of microfluidic channels embedded between plates of glass or similar moderate melting point substrates with a gradual softening point curve, or for assembly of glass-based substrates onto larger substrates, such as in flat panel display systems. 1. Thermal stresses and deflections of cross-ply laminated plates using refined plate theories SciTech Connect Khdeir, A.A.; Reddy, J.N. 1991-12-01 Exact analytical solutions of refined plate theories are developed to study the thermal stresses and deflections of cross-ply rectangular plates. The state-space approach in conjunction with the Levy method is used to solve exactly the governing equations of the theories under various boundary conditions. Numerical results of the higher-order theory of Reddy for thermal stresses and deflections are compared with those obtained using the classical and first-order plate theories. 14 refs. 2. Thermal stresses and deflections of cross-ply laminated plates using refined plate theories NASA Technical Reports Server (NTRS) Khdeir, A. A.; Reddy, J. N. 1991-01-01 Exact analytical solutions of refined plate theories are developed to study the thermal stresses and deflections of cross-ply rectangular plates. The state-space approach in conjunction with the Levy method is used to solve exactly the governing equations of the theories under various boundary conditions. Numerical results of the higher-order theory of Reddy for thermal stresses and deflections are compared with those obtained using the classical and first-order plate theories. 3. Earthquakes and plate tectonics USGS Publications Warehouse Spall, H. 1977-01-01 An explanation is to be found in plate tectonics, a concept which has revolutionized thinking in the Earth sciences in the last 10 years. The theory of plate tectonics combines many of the ideas about continental drift (originally proposed in 1912 by Alfred Wegener in Germany) and sea-floor spreading (suggested originally by Harry Hess of Princeton University). 4. Blue Willow Story Plates ERIC Educational Resources Information Center Fontes, Kris 2009-01-01 In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made. 5. Optimization of single plate-serial dilution spotting (SP-SDS) with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples. PubMed Thomas, Pious; Sekhar, Aparna C; Upreti, Reshmi; Mujawar, Mohammad M; Pasha, Sadiq S 2015-12-01 We propose a simple technique for bacterial and yeast cfu estimations from diverse samples with no prior idea of viable counts, designated as single plate-serial dilution spotting (SP-SDS) with the prime recommendation of sample anchoring (10 0 stocks). For pure cultures, serial dilutions were prepared from 0.1 OD (10 0 ) stock and 20 μl aliquots of six dilutions (10 1 -10 6 ) were applied as 10-15 micro-drops in six sectors over agar-gelled medium in 9-cm plates. For liquid samples 10 0 -10 5 dilutions, and for colloidal suspensions and solid samples (10% w/v), 10 1 -10 6 dilutions were used. Following incubation, at least one dilution level yielded 6-60 cfu per sector comparable to the standard method involving 100 μl samples. Tested on diverse bacteria, composite samples and Saccharomyces cerevisiae , SP-SDS offered wider applicability over alternative methods like drop-plating and track-dilution for cfu estimation, single colony isolation and culture purity testing, particularly suiting low resource settings. 6. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Measurement of optical absorption in polycrystalline CVD diamond plates by the phase photothermal method at a wavelength of 10.6 μm NASA Astrophysics Data System (ADS) Luk'yanov, A. Yu; Ral'chenko, Viktor G.; Khomich, A. V.; Serdtsev, E. V.; Volkov, P. V.; Savel'ev, A. V.; Konov, Vitalii I. 2008-12-01 A highly-efficient phase photothermal method is developed for quantitative measurements of the small optical absorption coefficient in thin plates made of highly transparent materials in which bulk losses significantly exceed surface losses. The bulk absorption coefficient at 10.6 μm is estimated in polycrystalline diamond plates grown from the vapour phase (a CVD diamond). The results are compared with those for natural and synthetic diamond single crystals and with the concentrations of nitrogen and hydrogen impurities. The absorption coefficient of the best samples of the CVD diamond did not exceed 0.06 cm-1, which, taking into account the high thermal conductivity of the CVD diamond (1800-2200 W mK-1 at room temperature), makes this material attractive for fabricating output windows of high-power CO2 lasers, especially for manufacturing large-size optics. 7. Dynamic Stabilization of Simple Fractures With Active Plates Delivers Stronger Healing Than Conventional Compression Plating PubMed Central Tsai, Stanley; Bliven, Emily K.; von Rechenberg, Brigitte; Kindt, Philipp; Augat, Peter; Henschel, Julia; Fitzpatrick, Daniel C.; Madey, Steven M. 2017-01-01 Objectives: Active plates dynamize a fracture by elastic suspension of screw holes within the plate. We hypothesized that dynamic stabilization with active plates delivers stronger healing relative to standard compression plating. Methods: Twelve sheep were randomized to receive either a standard compression plate (CP) or an active plate (ACTIVE) for stabilization of an anatomically reduced tibial osteotomy. In the CP group, absolute stabilization was pursued by interfragmentary compression with 6 cortical screws. In the ACTIVE group, dynamic stabilization after bony apposition was achieved with 6 elastically suspended locking screws. Fracture healing was analyzed weekly on radiographs. After sacrifice 9 weeks postsurgery, the torsional strength of healed tibiae and contralateral tibiae was measured. Finally, computed tomography was used to assess fracture patterns and healing modes. Results: Healing in both groups included periosteal callus formation. ACTIVE specimens had almost 6 times more callus area by week 9 (P < 0.001) than CP specimens. ACTIVE specimens recovered on average 64% of their native strength by week 9, and were over twice as strong as CP specimens, which recovered 24% of their native strength (P = 0.008). Microcomputed tomography demonstrated that compression plating induced a combination of primary bone healing and gap healing. Active plating consistently stimulated biological bone healing by periosteal callus formation. Conclusions: Compared with compression plating, dynamic stabilization of simple fractures with active plates delivers significantly stronger healing. PMID:27861456 8. Plating To Reinforce Welded Joints NASA Technical Reports Server (NTRS) Otousa, J. E. 1982-01-01 Electrodeposition used to strengthen welded joints gouged, nicked, or suffered other mechanical damage. Plating cell, typically of acrylic plastic such as poly (Methylmetacrylate), is assembled around part to be plated. Areas not to be plated are masked with plater's tape. Weld area is plated in standard nickel-plating process. 9. Investigation of pouring temperature and holding time for semisolid metal feedstock production NASA Astrophysics Data System (ADS) Razak, N. A.; Ahmad, A. H.; Rashidi, M. M. 2017-10-01 Semisolid metal (SSM) processing, as a kind of new technology that exploits forming of alloys between solidus and liquidus temperatures, has attracted great attention from investigators for its thixotropic behaviour as well as having advantages in reducing porosity, macrosegregation, and forming forces during shaping process. Various techniques are employed to produce feedstock with fine globular microstructures, and direct thermal method is one of them. In this paper, the effect from different pouring temperatures and holding times using a direct thermal method on microstructure and hardness of aluminium alloy 6061 is presented. Molten aluminium alloy 6061 was poured into a cylindrical copper mould and cooled down to the semisolid temperature before being quenched in water at room temperature. The effect of different pouring temperatures of 660 °C, 680 °C, 700 °C, and holding time of 20 s, and 60 s on the microstructure of aluminium alloy 6061 were investigated. From the micrographs, it was found that the most globular structures were achieved at processing parameters of 660 °C pouring temperature and 60 s holding time. The highest density and hardness of the samples were found at the same processing parameters. It can be concluded that the most spheroidal microstructure, the highest density, and the hardness were recorded at lower pouring temperature and longer holding time. 10. Reducing cylinder drag by adding a plate NASA Astrophysics Data System (ADS) Frolov, Vladimir A.; Kozlova, Anna S. 2017-10-01 Reducing the drag of bodies is a central problem of modern aerohydrodynamics. The paper presents theoretical and experimental studies of a new method for reducing the drag of a circular cylinder. To reduce the drag we propose to install a flat plate along the flow in front of the cylinder. The theoretical investigation of the drag was carried out using FlowSimulation software. An experimental study of the body drag was performed in an open wind tunnel. The drag coefficient results of the cylinder depended on the different locations of the flat plate relative to the cylinder. The following geometric characteristics of the cylinder/plate are studied: the width of the gap between the cylinder and the plate and the meridional angle of the plate with respect to the cylinder. On the basis of Numerical and Physical Modeling, the values of the drag coefficient for the cylinder/plate are presented. The results included establishment the locations of the cylinder/plate which give the value of the drag coefficient for the combination of the two bodies. That total drag coefficient of the cylinder/plate can be less than the cylinder alone. 11. AERIAL OF SHUTTLE LANDING FACILITY [SLF] POURING OF CONCRETE NASA Technical Reports Server (NTRS) 1975-01-01 AERIAL OF SHUTTLE LANDING FACILITY [SLF] POURING OF CONCRETE KSC-375C-10036.31 108-KSC-375C-10036.31, P-21426, ARCHIVE-04502 Aerial oblique of Shuttle runway facilities. Pouring concrete on runway. Direction north - altitude 100'. 12. Development of monitoring method of spatial neutron distribution in neutrons-gamma rays mixed field using imaging plate for NCT--depression of the field. PubMed Tanaka, Kenichi; Endo, Satoru; Hoshi, Masaharu; Takada, Jun 2011-12-01 The degree of depression in the neutron field caused by neutron absorption in the materials of an imaging plate (IP) was investigated using MCNP-4C. Consequently, the IP doped with Gd, which reproduced the distribution of (157)Gd(n,γ)(158)Gd reaction rate in the previous study, depresses the relative distribution by about 50%. The depression for the IP in which Gd is replaced with similar amount of B atoms was estimated to be about 10%. The signal intensity for this IP is estimated to be at a similar level with that for Gd-doped IP. Copyright © 2011 Elsevier Ltd. All rights reserved. 13. Bead on Plate Temper Pass Study: Thermal and Microhardness Study DTIC Science & Technology 2009-09-01 par soudage fournit l’énergie cruciale pour réaliser le recuit de la martensite et, ultérieurement, en restaurer la ductilité et la ténacité; le...thermocouple within different regions of the HAZ. In nearly all cases the thermocouples were suitably positioned with a few being consumed within the fusion...important in the design of weld tempering sequences. For the current combination of HY-80 base plate and AWS 9016G welding consumable , it is the HY-80 base 14. Aeroheating model advancements featuring electroless metallic plating NASA Technical Reports Server (NTRS) Stalmach, C. J., Jr.; Goodrich, W. D. 1976-01-01 Discussed are advancements in wind tunnel model construction methods and hypersonic test data demonstrating the methods. The general objective was to develop model fabrication methods for improved heat transfer measuring capability at less model cost. A plated slab model approach was evaluated with cast models containing constantan wires that formed single-wire-to-plate surface thermocouple junctions with a seamless skin of electroless nickel alloy. The surface of a space shuttle orbiter model was selectively plated with scaled tiles to simulate, with high fidelity, the probable misalignments of the heatshield tiles on a flight vehicle. Initial, Mach 8 heating results indicated a minor effect of tile misalignment roughness on boundary layer transition, implying a possible relaxation of heatshield manufacturing tolerances. Some loss of the plated tiles was experienced when the model was tested at high heating rates. 15. Comparison of solid-phase cytometry and the plate count method for the evaluation of the survival of bacteria in pharmaceutical oils. PubMed De Prijck, K; Peeters, E; Nelis, H J 2008-12-01 To compare the survival of four bacterial strains (Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Pseudomonas aeruginosa) in pharmaceutical oils, including jojoba oil/tea tree oil, carbol oil, jojoba oil and sesame oil. Oils were spiked with the test bacteria in a concentration of 10(4) CFU ml(-1). Bacteria were extracted from oils with phosphate-buffered saline containing 0.5% Tween 20. Aliquots of the pooled water layers were analysed by solid-phase cytometry and plate counting. Plate counts dropped to zero for all test strains exposed for 24 h to three of the four oils. In contrast, significant numbers of viable cells were still detected by SPC, except in the jojoba oil/tea tree oil mixture and partly in sesame oil. Exposure of bacteria for 24 h to the two oils containing an antimicrobial led to a loss of their culturability but not necessarily of their viability. The antibacterial activity of the jojoba oil/tea tree oil mixture supersedes that of carbol oil. These in vitro data suggest that the jojoba oil/tea tree oil mixture more than carbol oil inhibits bacterial proliferation when used for intermittent self-catherization. 16. Aerial ultrasound source with a circular vibrating plate attached to a rigid circumferential wall NASA Astrophysics Data System (ADS) Kuratomi, Ryo; Asami, Takuya; Miura, Hikaru 2018-07-01 We fabricate a transverse vibrating plate attached to a rigid wall integrated at the circumference of a circular vibrating plate that allows a strong sound wave field to be formed in the area encoded by the vibrating plate and rigid wall by installing a wall such as a reflective plate on the rigid wall. The design method for the circular vibrating plate attached to a rigid circumferential wall is investigated. A method of forming a strong standing wave field in an enclosed area constructed with a vibrating plate, cylindrical reflective plate, and parallel reflective plate is developed. 17. INTERIOR VIEW, LOOKING WEST, WITH CRANE OPERATOR, TED SEALS, POURING ... Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey INTERIOR VIEW, LOOKING WEST, WITH CRANE OPERATOR, TED SEALS, POURING MOLTEN METAL INTO A 1,300 TON ELECTRIC HOLDING FURNACE OR MIXER. AN ELECTRONIC SCALE RECORDED THAT 50.5 TONS OF METAL WERE POURED INTO THE FURNACE DURING THIS POUR. - American Cast Iron Pipe Company, Mixer Building, 1501 Thirty-first Avenue North, Birmingham, Jefferson County, AL 18. Tectonic Plate Movement. ERIC Educational Resources Information Center Landalf, Helen 1998-01-01 Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR) 19. What's On Your Plate? MedlinePlus ... Table of Contents What's On Your Plate? Smart Food Choices for Healthy Aging www.nia.nih.gov/health/ ... calories in" and "calories out," and making good food choices as you age. Shopping Tips See how planning ... 20. Growth Plate Injuries MedlinePlus ... Download Download EPUB Download PDF What are they? Points To Remember About Growth Plate Injuries Injuries to ... Neurological disorders that cause people to lose their balance and fall. Some inherited disorders. Bone infections. Metabolic ... 1. License plate recognition. DOT National Transportation Integrated Search 2008-01-01 License Plate Recognition (LPR) technology has been used for off-line automobile enforcement purposes. The technology has seen mixed success with correct reading rate around 60 to 70% depending on the specific application and environment. This limita... 2. BAO Plate Archive Project NASA Astrophysics Data System (ADS) Mickaelian, A. M.; Gigoyan, K. S.; Gyulzadyan, M. V.; Paronyan, G. M.; Abrahamyan, H. V.; Andreasyan, H. R.; Azatyan, N. M.; Kostandyan, G. R.; Samsonyan, A. L.; Mikayelyan, G. A.; Farmanyan, S. V.; Harutyunyan, V. L. 2017-12-01 We present the Byurakan Astrophysical Observatory (BAO) Plate Archive Project that is aimed at digitization, extraction and analysis of archival data and building an electronic database and interactive sky map. BAO Plate Archive consists of 37,500 photographic plates and films, obtained with 2.6m telescope, 1m and 0.5m Schmidt telescopes and other smaller ones during 1947-1991. The famous Markarian Survey (or the First Byurakan Survey, FBS) 2000 plates were digitized in 2002-2005 and the Digitized FBS (DFBS, www.aras.am/Dfbs/dfbs.html) was created. New science projects have been conducted based on this low-dispersion spectroscopic material. Several other smaller digitization projects have been carried out as well, such as part of Second Byurakan Survey (SBS) plates, photographic chain plates in Coma, where the blazar ON 231 is located and 2.6m film spectra of FBS Blue Stellar Objects. However, most of the plates and films are not digitized. In 2015, we have started a project on the whole BAO Plate Archive digitization, creation of electronic database and its scientific usage. Armenian Virtual Observatory (ArVO, www.aras.am/Arvo/arvo.htm) database will accommodate all new data. The project runs in collaboration with the Armenian Institute of Informatics and Automation Problems (IIAP) and will continues during 4 years in 2015-2018. The final result will be an Electronic Database and online Interactive Sky map to be used for further research projects. ArVO will provide all standards and tools for efficient usage of the scientific output and its integration in international databases. 3. Mechanical design and analysis of focal plate for gravity deformation NASA Astrophysics Data System (ADS) Wang, Jianping; Chu, Jiaru; Hu, Hongzhuan; Li, Kexuan; Zhou, Zengxiang 2014-07-01 The surface accuracy of astronomical telescope focal plate is a key indicator to precision stellar observation. To conduct accurate deformation measurement for focal plate in different status, a 6-DOF hexapod platform was used for attitude adjustment. For the small adjustment range of a classic 6-DOF hexapod platform, an improved structural arrangement method was proposed in the paper to achieve ultimate adjustment of the focal plate in horizontal and vertical direction. To validate the feasibility of this method, an angle change model which used ball hinge was set up for the movement and base plate. Simulation results in MATLAB suggested that the ball hinge angle change of movement and base plate is within the range of the limiting angle in the process of the platform plate adjusting to ultimate attitude. The proposed method has some guiding significance for accurate surface measurement of focal plate. 4. Strongly coupled stress waves in heterogeneous plates. NASA Technical Reports Server (NTRS) Wang, A. S. D.; Chou, P. C.; Rose, J. L. 1972-01-01 Consideration of coupled stress waves generated by an impulsive load applied at one end of a semiinfinite plate. For the field equations governing the one-dimensional coupled waves a hyperbolic system of equations is obtained in which a strong coupling in the second derivatives exists. The method of characteristics described by Chou and Mortimer (1967) is extended to cover the case of strong coupling, and a study is made of the transient stress waves in a semiinfinite plate subjected to an initial step input. Coupled discontinuity fronts are found to propagate at different velocities. The normal plate stress and the bending moment at different time regimes are illustrated by graphs. 5. Joining by plating: optimization of occluded angle SciTech Connect Dini, J.W.; Johnson, H.R.; Kan, Y.R. 1978-11-01 An empirical method has been developed for predicting the minimum angle required for maximum joint strength for materials joined by plating. This is done through a proposed power law failure function, whose coefficients are taken from ring shear and conical head tensile data for plating/substrate combinations and whose exponent is determined from one set of plated-joint data. Experimental results are presented for Al-Ni-Al (7075-T6) and AM363-Ni-AM363 joints, and the failure function is used to predict joint strengths for Al-Ni-Al (2024-T6), UTi-Ni-UTi, and Be-Ti-Be. 6. Weld bead reinforcement removal: A method of improving the strength and ductility of peaked welds in 2219-T87 aluminum alloy plate NASA Technical Reports Server (NTRS) Lovoy, C. V. 1979-01-01 The results of a study to determine the degree to which the ductility and tensile properties of peaked welds could be enhanced by removing the reinforcing bead and fairing the weld nugget into the adjacent parent metal are presented. The study employed 2219-T87 aluminum alloy plate, tungsten inert gas (TIG) welding, and 2319 filler wire. The study concluded that significant improvements in peak weld, ultimate strength, and ductility can be obtained through removal and fairing of the weld reinforcing bead. The specimens so treated and tested in this program exhibited ultimate strength improvements of 2 to 3 percent for peak angles of 5.8 to 10 degrees and 10 to 22 percent for welds with peak angles of 11.7 to 16.9 degrees. It was also determined that removal of the weld bead enhanced the ability of peaked welds to straighten when exposed to cyclic loading at stress levels above the yield strength. 7. Computing dispersion curves of elastic/viscoelastic transversely-isotropic bone plates coupled with soft tissue and marrow using semi-analytical finite element (SAFE) method. PubMed Nguyen, Vu-Hieu; Tran, Tho N H T; Sacchi, Mauricio D; Naili, Salah; Le, Lawrence H 2017-08-01 We present a semi-analytical finite element (SAFE) scheme for accurately computing the velocity dispersion and attenuation in a trilayered system consisting of a transversely-isotropic (TI) cortical bone plate sandwiched between the soft tissue and marrow layers. The soft tissue and marrow are mimicked by two fluid layers of finite thickness. A Kelvin-Voigt model accounts for the absorption of all three biological domains. The simulated dispersion curves are validated by the results from the commercial software DISPERSE and published literature. Finally, the algorithm is applied to a viscoelastic trilayered TI bone model to interpret the guided modes of an ex-vivo experimental data set from a bone phantom. Copyright © 2017 Elsevier Ltd. All rights reserved. 8. Miroirs multicouches C/SI a incidence normale pour la region spectrale 25-40 nanometres NASA Astrophysics Data System (ADS) Grigonis, Marius Nous avons propose la nouvelle combinaison de materiaux, C/Si, pour la fabrication de miroirs multicouches a incidence normale dans la region spectrale 25-40 nm. Les resultats experimentaux montrent que cette combinaison possede une reflectivite d'environ ~25% dans la region spectrale 25-33 nm et une reflectivite d'environ ~23% dans la region spectrale 33-40 nm. Ces valeurs de reflectivite sont les plus grandes obtenues jusqu'a maintenant dans la region spectrale 25-40 nm. Les miroirs multicouches ont ete par la suite caracterises par microscopie electronique a transmission, par diverses techniques de diffraction des rayons X et par spectroscopies d'electrons AES et ESCA. La resistance des miroirs aux temperatures elevees a ete egalement etudiee. Les resultats fournis par les methodes de caracterisation indiquent que cette combinaison possede des caracteristiques tres prometteuses pour son application comme miroir pour les rayons X mous. 9. A Statistical Treatment of Bioassay Pour Fractions NASA Technical Reports Server (NTRS) Barengoltz, Jack; Hughes, David W. 2014-01-01 The binomial probability distribution is used to treat the statistics of a microbiological sample that is split into two parts, with only one part evaluated for spore count. One wishes to estimate the total number of spores in the sample based on the counts obtained from the part that is evaluated (pour fraction). Formally, the binomial distribution is recharacterized as a function of the observed counts (successes), with the total number (trials) an unknown. The pour fraction is the probability of success per spore (trial). This distribution must be renormalized in terms of the total number. Finally, the new renormalized distribution is integrated and mathematically inverted to yield the maximum estimate of the total number as a function of a desired level of confidence ( P(pour fraction. The extension to recovery efficiency corrections is also presented. Now the product of recovery efficiency and pour fraction may be small enough that the likely value may be much larger than the usual calculation: the number of spores divided by that product. The use of this analysis would not be limited to microbiological data. 10. Scaling of energy absorbing composite plates NASA Technical Reports Server (NTRS) Jackson, Karen; Morton, John; Traffanstedt, Catherine; Boitnott, Richard 1992-01-01 The energy absorption response and crushing characteristics of geometrically scaled graphite-Kevlar epoxy composite plates were investigated. Three different trigger mechanisms including chamfer, notch, and steeple geometries were incorporated into the plate specimens to initiate crushing. Sustained crushing was achieved with a simple test fixture which provided lateral support to prevent global buckling. Values of specific sustained crushing stress (SSCS) were obtained which were comparable to values reported for tube specimens from previously published data. Two sizes of hybrid plates were fabricated; a baseline or model plate, and a full-scale plate with in-plane dimensions scaled by a factor of two. The thickness dimension of the full-scale plates was increased using two different techniques; the ply-level method in which each ply orientation in the baseline laminate stacking sequence is doubled, and the sublaminate technique in which the baseline laminate stacking sequence is repeated as a group. Results indicated that the SSCS is independent of trigger mechanism geometry. However, a reduction in the SSCS of 10-25 percent was observed for the full-scale plates as compared with the baseline specimens, indicating a scaling effect in the crushing response. 11. Scaling of energy absorbing composite plates NASA Technical Reports Server (NTRS) Jackson, Karen; Lavoie, J. Andre; Morton, John 1994-01-01 The energy absorption response and crushing characteristics of geometrically scaled graphite-Kevlar epoxy composite plates were investigated. Two different trigger mechanisms including notch, and steeple geometries were incorporated into the plate specimens to initiate crushing. Sustained crushing was achieved with a new test fixture which provided lateral support to prevent global buckling. Values of specific sustained crushing stress (SSCS) were obtained which were lower than values reported for tube specimens from previously published data. Two sizes of hybrid plates were fabricated; a baseline or model plate, and a full-scale plate with inplane dimensions scaled by a factor of two. The thickness dimension of the full-scale plates was increased using two different techniques: the ply-level method in which each ply orientation in the baseline laminate stacking sequence is doubled, and the sublaminate technique in which the baseline laminate stacking sequence is repeated as a group. Results indicated that the SSCS has a small dependence on trigger mechanism geometry. However, a reduction in the SSCS of 10-25% was observed for the full-scale plates as compared with the baseline specimens, indicating a scaling effect in the crushing response. 12. Scaling of energy absorbing composite plates NASA Astrophysics Data System (ADS) Jackson, Karen; Morton, John; Traffanstedt, Catherine; Boitnott, Richard The energy absorption response and crushing characteristics of geometrically scaled graphite-Kevlar epoxy composite plates were investigated. Three different trigger mechanisms including chamfer, notch, and steeple geometries were incorporated into the plate specimens to initiate crushing. Sustained crushing was achieved with a simple test fixture which provided lateral support to prevent global buckling. Values of specific sustained crushing stress (SSCS) were obtained which were comparable to values reported for tube specimens from previously published data. Two sizes of hybrid plates were fabricated; a baseline or model plate, and a full-scale plate with in-plane dimensions scaled by a factor of two. The thickness dimension of the full-scale plates was increased using two different techniques; the ply-level method in which each ply orientation in the baseline laminate stacking sequence is doubled, and the sublaminate technique in which the baseline laminate stacking sequence is repeated as a group. Results indicated that the SSCS is independent of trigger mechanism geometry. However, a reduction in the SSCS of 10-25 percent was observed for the full-scale plates as compared with the baseline specimens, indicating a scaling effect in the crushing response. 13. Development efforts to improve curved-channel microchannel plates NASA Technical Reports Server (NTRS) Corbett, M. B.; Feller, W. B.; Laprade, B. N.; Cochran, R.; Bybee, R.; Danks, A.; Joseph, C. 1993-01-01 Curved-channel microchannel plate (C-plate) improvements resulting from an ongoing NASA STIS microchannel plate (MCP) development program are described. Performance limitations of previous C-plates led to a development program in support of the STIS MAMA UV photon counter, a second generation instrument on the Hubble Space Telescope. C-plate gain, quantum detection efficiency, dark noise, and imaging distortion, which are influenced by channel curvature non-uniformities, have all been improved through use of a new centrifuge fabrication technique. This technique will be described, along with efforts to improve older, more conventional shearing methods. Process optimization methods used to attain targeted C-plate performance goals will be briefly characterized. Newly developed diagnostic measurement techniques to study image distortion, gain uniformity, input bias angle, channel curvature, and ion feedback, will be described. Performance characteristics and initial test results of the improved C-plates will be reported. Future work and applications will also be discussed. 14. Actively controlling coolant-cooled cold plate configuration SciTech Connect Chainer, Timothy J.; Parida, Pritish R. A method is provided to facilitate active control of thermal and fluid dynamic performance of a coolant-cooled cold plate. The method includes: monitoring a variable associated with at least one of the coolant-cooled cold plate or one or more electronic components being cooled by the cold plate; and dynamically varying, based on the monitored variable, a physical configuration of the cold plate. By dynamically varying the physical configuration, the thermal and fluid dynamic performance of the cold plate are adjusted to, for example, optimally cool the one or more electronic components, and at the same time, reduce cooling power consumptionmore » used in cooling the electronic component(s). The physical configuration can be adjusted by providing one or more adjustable plates within the coolant-cooled cold plate, the positioning of which may be adjusted based on the monitored variable.« less 15. Cadmium plating replacements NASA Technical Reports Server (NTRS) Nelson, Mary J.; Groshart, Earl C. 1995-01-01 The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating. 16. Bipolar battery plate NASA Technical Reports Server (NTRS) Rowlette, John J. (Inventor) 1987-01-01 A liquid-impermeable plate (10) having through-plate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with led spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet. 17. An alternative method for the treatment of waste produced at a dye and a metal-plating industry using natural and/or waste materials. PubMed Fatta, Despo; Papadopoulos, Achilleas; Stefanakis, Nikos; Loizidou, Maria; Savvides, Chrysanthos 2004-08-01 The aim of this study was to develop cost-effective, appropriate solidification technologies for treating hazardous industrial wastes that are currently disposed of in ways that may threaten the quality of local groundwater. One major objective was to use materials other than cement, and preferably materials that are themselves wastes, as the solidification additives, namely using wastes to treat wastes or locally available natural material. This research examines the cement-based and lime-based stabilization/solidification (S/S) techniques applied for waste generated at a metal-plating industry and a dye industry. For the lime-based S/S process the following binder mixtures were used: cement kiln dust/ lime, bentonite/lime and gypsum/lime. For the cement-based S/S process three binder mixtures were used: cement kiln dust/cement, bentonite/cement and gypsum/cement. The leachability of the wastes was evaluated using the toxicity characteristic leaching procedure. The applicability and optimum weight ratio of the binder mixtures were estimated using the unconfined compressive strength test. The optimum ratio mixtures were mixed with waste samples in different ratios and cured for 28 days in order to find the S/S products with the highest strength and lowest leachability at the same time. The results of this work showed that the cement-and lime-based S/S process, using cement kiln dust and bentonite as additives can be effectively used in order to treat industrial waste. 18. Large drinks are no mistake: Glass size, but not shape, affects alcoholic beverage drink pours PubMed Central Kerr, William C.; Patterson, Deidre; Koenen, Mary Albert; Greenfield, Thomas K. 2009-01-01 Introduction and Aims Drink alcohol content has been shown to be variable and is an important determinant of alcohol intake. This study evaluates claims regarding the effects of glass size and glass shape on the amount of alcohol in on-premise drinks. Design and Methods Wine and spirits drinks were purchased and measured in 80 on-premise establishments in 10 Northern California Counties. Drink alcohol content was measured as the liquid volume of the drink multiplied by the percentage alcohol by volume of given brands or from analysis of mixed drink and wine samples. Results Larger glass size was associated with larger on-premise pours of straight shots and mixed drinks served in the relatively large pint glass and variable “other” glass type were found to contain more alcohol than drinks served in a short wide glass. No significant differences were found for other drink types. Drinks poured in short wide glasses were not found to contain more alcohol than drinks poured in tall thin glasses. Bars with mostly black patrons were found to serve spirits drinks with more alcohol than bars with other patron types. Discussion and Conclusions Glass shape does not affect actual drink pours in the US but glass size does in some cases. Drinkers should measure wine and spirits pours at home to achieve standard drink amounts and consumer education programs should foster awareness of the relatively high drink alcohol content of on-premise wine and mixed spirits drinks. More research is needed to evaluate potential differences in drink pours by patron race and ethnicity. PMID:19594789 19. The Elasto-Plastic Stability of Plates NASA Technical Reports Server (NTRS) Ilyushin, A. A. 1947-01-01 This article explains results developed from the following research: 'The Stability of Plates and Shells beyond the Elastic Limit.' A significant improvement is found in the derivation of the relations between the stress factors and the strains resulting from the instability of plates and shells. In a strict analysis, the problem reduces to the solution of two simultaneous nonlinear partial differential equations of the fourth order in the deflection and stress function, and in the approximate analysis to a single linear equation of the Bryan type. Solutions are given for the special cases of a rectangular plate buckling into a cylindrical form, and of an arbitrarily shaped plate under uniform compression. These solutions indicate that the accuracy obtained by the approximate method is satisfactory. 20. Elastostatic stress analysis of orthotropic rectangular center-cracked plates NASA Technical Reports Server (NTRS) Gyekenyesi, G. S.; Mendelson, A. 1972-01-01 A mapping-collocation method was developed for the elastostatic stress analysis of finite, anisotropic plates with centrally located traction-free cracks. The method essentially consists of mapping the crack into the unit circle and satisfying the crack boundary conditions exactly with the help of Muskhelishvili's function extension concept. The conditions on the outer boundary are satisfied approximately by applying the method of least-squares boundary collocation. A parametric study of finite-plate stress intensity factors, employing this mapping-collocation method, is presented. It shows the effects of varying material properties, orientation angle, and crack-length-to-plate-width and plate-height-to-plate-width ratios for rectangular orthotropic plates under constant tensile and shear loads. 1. Reduced Plating Ignitron NASA Technical Reports Server (NTRS) Polzin, Kurt A (Inventor); Pearson, J Boise (Inventor) 2014-01-01 An ignitron apparatus has an airtight tubular housing having a first sealed end and a second sealed end. An anode is connected at the first sealed end, projecting into the housing, and a recess at the second sealed and forms a well which contains a quantity of liquid gallium or gallium alloy making up the cathode. An ignitor projects through the liquid metal and into the housing. The inner surface of the housing includes at least one plating-reduction structure to prevent electrical shorting of the apparatus caused by plating of the liquid metal. 2. NICKEL PLATING PROCESS DOEpatents Hoover, T.B.; Zava, T.E. 1959-05-12 A simplified process is presented for plating nickel by the vapor decomposition of nickel carbonyl. In a preferred form of the invention a solid surface is nickel plated by subjecting the surface to contact with a mixture containing by volume approximately 20% nickel carbonyl vapor, 2% hydrogen sulfide and .l% water vapor or 1% oxygen and the remainder carbon dioxide at room temperature until the desired thickness of nickel is obtained. The advantage of this composition over others is that the normally explosive nickel carbonyl is greatly stabilized. 3. Effect of Storage Time of Extended-Pour and Conventional Alginate Impressions on Dimensional Accuracy of Casts PubMed Central Rohanian, Ahmad; Ommati Shabestari, Ghasem; Zeighami, Somayeh; Samadi, Mohammad Javad; Shamshiri, Ahmad Reza 2014-01-01 Objectives: Some manufacturers claim to have produced new irreversible hydro-colloids that are able to maintain their dimensional stability during storage. The present study evaluated the effect of storage time on dimensional stability of three alginates: Hydrogum 5, Tropicalgin and Alginoplast. Materials and Methods: In this experimental in-vitro trial, a total of 90 alginate impressions were made from a Dentoform model using Hydrogum 5, Tropicalgin and Alginoplast alginates. The impressions were stored in a sealed plastic bag without a damp paper towel for 0, 24, 48, 72 and 120 hours and then poured with type III dental stone. Cross-arch (facial of 6 to facial of 6 on the opposite side) and antero-posterior (distal of right first molar to the ipsilateral central incisor) measurements were made with a digital caliper on the casts. Data were analyzed by two-way and one-way ANOVA and Tukey’s post-hoc test (P<0.05). Results: Alginate type and the pouring time significantly affected the dimensional stability of alginate impressions (both Ps<0.001). Pouring of Hydrogum 5 impressions can be delayed for up to 120 hours without significant dimensional changes. Alginoplast impressions may be poured after 72 hours, but Tropicalgin should be poured immediately and the storage time should not be more than 24 hours. Conclusion: Immediate pouring of alginate impressions provides the highest accuracy in reproducing the teeth and adjacent tissues; however, this study demonstrated that pouring may be delayed for up to five days using extended-pour (Hydrogum 5) alginates. PMID:25628695 4. Hydrodynamics of a flexible plate between pitching rigid plates NASA Astrophysics Data System (ADS) Kim, Junyoung; Kim, Daegyoum 2017-11-01 The dynamics of a flexible plate have been studied as a model problem in swimming and flying of animals and fluid-structure interaction of plants and flags. Motivated by fish schooling and an array of sea grasses, we investigate the dynamics of a flexible plate closely placed between two pitching rigid plates. In most studies on passive deformation of the flexible plate, the plate is immersed in a uniform flow or a wavy flow. However, in this study, the flexible plate experiences periodic deformation by the oscillatory flow generated by the prescribed pitching motion of the rigid plates. In our model, the pitching axes of the rigid plates and the clamping position of the flexible plate are aligned on the same line. The flexible plate shows various responses depending on length and pitching frequency of rigid plates, thickness of a flexible plate, and free-stream velocity. To find the effect of each variable on the response of the flexible plate, amplitude of a trailing edge and modal contribution of a flapping motion are compared, and flow structure around the flexible plate is examined. 5. Plate on plate osteosynthesis for the treatment of nonhealed periplate fractures. PubMed Arealis, Georgios; Nikolaou, Vassilios S; Lacon, Andrew; Ashwood, Neil; Hamlet, Mark 2014-01-01 Purpose. The purpose of this paper is to present our technique for the treatment of periplate fractures. Methods. From 2009 to 2012 we treated three patients. In all cases the existing plate was left and the new one placed over the existing. Locking screws were placed through both plates. The other screws in the new plate were used as best suited the fracture. Results. In all cases less than 6 months had passed between fractures. None of the original fractures had healed. Mean followup was 2 years. All fractures proceeded to union within 7 months. No complications were recorded. All the patients returned to their normal activities and were satisfied with the results of their treatment. Conclusion. Our plate on plate technique is effective for the treatment of periplate fractures. A solid fusion can be achieved at the new fracture site without disturbing the previous fixation. 6. Congruency of scapula locking plates: implications for implant design. PubMed Park, Andrew Y; DiStefano, James G; Nguyen, Thuc-Quyen; Buckley, Jenni M; Montgomery, William H; Grimsrud, Chris D 2012-04-01 We conducted a study to evaluate the congruency of fit of current scapular plate designs. Three-dimensional image-processing and -analysis software, and computed tomography scans of 12 cadaveric scapulae were used to generate 3 measurements: mean distance from plate to bone, maximum distance, and percentage of plate surface within 2 mm of bone. These measurements were used to quantify congruency. The scapular spine plate had the most congruent fit in all 3 measured variables. The lateral border and glenoid plates performed statistically as well as the scapular spine plate in at least 1 of the measured variables. The medial border plate had the least optimal measurements in all 3 variables. With locking-plate technology used in a wide variety of anatomical locations, the locking scapula plate system can allow for a fixed-angle construct in this region. Our study results showed that the scapular spine, glenoid, and lateral border plates are adequate in terms of congruency. However, design improvements may be necessary for the medial border plate. In addition, we describe a novel method for quantifying hardware congruency, a method that can be applied to any anatomical location. 7. Reconstructing Plate Motions on Europa with GPlates NASA Astrophysics Data System (ADS) Cutler, B. B.; Collins, G. C.; Prockter, L. M.; Patterson, G.; Kattenhorn, S. A.; Rhoden, A.; Cooper, C. M. 2015-12-01 Observations of past plate tectonic - like motions in Europa's icy lithosphere have been reported in previous studies. Quantifying the nature, age, and amount of plate motion is important for geophysical models of Europa's ice shell and for astrobiology, since subsumed pates could drive the flow of nutrients into the subsurface ocean. We have used GPlates software (Williams et al., GSA Today 2012) and a mosaic of regional-resolution Galileo SSI data from orbits E11, E15, E17, and E19 to make interactive reconstructions of both the Northern Falga region (60N, 220W) and the Castalia Macula region (0N, 225W). The advantage of this method is that plate motions are calculated on a sphere, while still maintaining the original Galileo image pieces in their proper geographic locations. Previous work on the Castalia Macula region (Patterson et al. J.Struct.Geol. 2006) and the adjacent Phaidra Linea region (Patterson and Ernst, LPSC 2011) found offsets along spreading boundaries, and then calculated the best fit finite rotations to close those offsets. Though this method is mathematically rigorous and gives a statistical goodness of fit, it is not easy to test multiple hypotheses for candidate piercing points or divisions of candidate plate boundaries. Through the interactive environment, we found that we could better account for observed offsets in this region by breaking it into 32 different plates. Patterson and Ernst broke the Phaidra region into 6 plates which exhibited nonrigid behavior, where our study breaks it into 16 rigid plates. The Northern Falga Regio area is interesting due to the potential for large amounts of subsumption of Europa's icy crust in this location. The previous reconstruction (Kattenhorn and Prockter, Nat.Geosci. 2014) was based on planar geometry, and we have replicated these results using a spherically-based reconstruction. We will present the plate maps and reconstructions for both of these regions, along with the best fit rotation poles. 8. The Plate Tectonics Project ERIC Educational Resources Information Center Hein, Annamae J. 2011-01-01 The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will… 9. BAO plate archive digitization NASA Astrophysics Data System (ADS) Mickaelian, A. M.; Nikoghosyan, E. H.; Gigoyan, K. S.; Paronyan, G. M.; Abrahamyan, H. V.; Andreasyan, H. R.; Azatyan, N. M.; Kostandyan, G. R.; Khachatryan, K. G.; Vardanyan, A. V.; Gyulzadyan, M. V.; Mikayelyan, G. A.; Farmanyan, S. V.; Knyazyan, A. V. Astronomical plate archives created on the basis of numerous observations at many observatories are important part of the astronomical heritage. Byurakan Astrophysical Observatory (BAO) plate archive consists of 37,000 photographic plates and films, obtained at 2.6m telescope, 1m and 0.5m Schmidt telescopes and other smaller ones during 1947-1991. In 2015, we have started a project on the whole BAO Plate Archive digitization, creation of electronic database and its scientific usage. A Science Program Board is created to evaluate the observing material, to investigate new possibilities and to propose new projects based on the combined usage of these observations together with other world databases. The Executing Team consists of 11 astronomers and 2 computer scientists and will use 2 EPSON Perfection V750 Pro scanners for the digitization. The project will run during 3 years in 2015-2017 and the final result will be an electronic database and online interactive sky map to be used for further research projects. 10. Unitary plate electrode NASA Technical Reports Server (NTRS) Rowlette, John J. (Inventor); Clough, Thomas J. (Inventor); Josefowicz, Jack Y. (Inventor); Sibert, John W. (Inventor) 1985-01-01 The unitary electrode (10) comprises a porous sheet (12) of fiberglass the strands (14) of which contain a coating (16) of conductive tin oxide. The lower portion of the sheet contains a layer (18) of resin and the upper layer (20) contains lead dioxide forming a positive active electrode on an electrolyte-impervious layer. The strands (14) form a continuous conduction path through both layers (16, 18). Tin oxide is prevented from reduction by coating the surface of the plate facing the negative electrode with a conductive, impervious layer resistant to reduction such as a thin film (130) of lead or graphite filled resin adhered to the plate with a layer (31) of conductive adhesive. The plate (10) can be formed by casting a molten resin from kettle (60) onto a sheet of glass wool (56) overlying a sheet of lead foil and then applying positive active paste from hopper (64) into the upper layer (68). The plate can also be formed by passing an assembly of a sheet ( 80) of resin, a sheet (86) of sintered glass and a sheet (90) of lead between the nip (92) of heated rollers (93, 95) and then filling lead oxide into the pores (116) of the upper layer (118). 11. Nuclear reactor alignment plate configuration DOEpatents Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R 2014-01-28 An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass. 12. The Development and Evaluation of a Portion Plate for Youth: A Pilot Study ERIC Educational Resources Information Center Bohnert, Amy M.; Randall, Edin T.; Tharp, Stephanie; Germann, Julie 2011-01-01 Objective: To develop and evaluate a portion plate for adolescents (Nutri-plate). Methods: Sixteen African American adolescents (mean age = 12.94 years; 66% male) were randomized to participate in either plate design or nutrition education sessions. Adolescents' input was used to create the Nutri-plate, and participants' food selection and intake… 13. History of internal fixation with plates (part 2): new developments after World War II; compressing plates and locked plates. PubMed Hernigou, Philippe; Pariat, Jacques 2017-07-01 The first techniques of operative fracture with plates were developed in the 19th century. In fact, at the beginning these methods consisted of an open reduction of the fracture usually followed by a very unstable fixation. As a consequence, the fracture had to be opened with a real risk of (sometimes lethal) infection, and due to unstable fixation, protection with a cast was often necessary. During the period between World Wars I and II, plates for fracture fixation developed with great variety. It became increasingly recognised that, because a fracture of a long bone normally heals with minimal resorption at the bone ends, this may result in slight shortening and collapse, so a very rigid plate might prevent such collapse. However, as a consequence, delayed healing was observed unless the patient was lucky enough to have the plate break. One way of dealing with this was to use a slotted plate in which the screws could move axially, but the really important advance was recognition of the role of compression. After the first description of compression by Danis with a "coapteur", Bagby and Müller with the AO improved the technique of compression. The classic dynamic compression plates from the 1970s were the key to a very rigid fixation, leading to primary bone healing. Nevertheless, the use of strong plates resulted in delayed union and the osteoporosis, cancellous bone, comminution, and/or pathological bone resulted in some failures due to insufficient stability. Finally, new devices represented by locking plates increased the stability, contributing to the principles of a more biological osteosynthesis while giving enough stability to allow immediate full weight bearing in some patients. 14. Measurement of Stress Distribution Around a Circular Hole in a Plate Under Bending Moment Using Phase-shifting Method with Reflective Polariscope Arrangement NASA Astrophysics Data System (ADS) Baek, Tae Hyun Photoelasticity is one of the most widely used whole-field optical methods for stress analysis. The technique of birefringent coatings, also called the method of photoelastic coatings, extends the classical procedures of model photoelasticity to the measurement of surface strains in opaque models made of any structural material. Photoelastic phase-shifting method can be used for the determination of the phase values of isochromatics and isoclinics. In this paper, photoelastic phase-shifting technique and conventional Babinet-Soleil compensation method were utilized to analyze a specimen with a triangular hole and a circular hole under bending. Photoelastic phase-shifting technique is whole-field measurement. On the other hand, conventional compensation method is point measurement. Three groups of results were obtained by phase-shifting method with reflective polariscope arrangement, conventional compensation method and FEM simulation, respectively. The results from the first two methods agree with each other relatively well considering experiment error. The advantage of photoelastic phase-shifting method is that it is possible to measure the stress distribution accurately close to the edge of holes. 15. Evaluation of finger plate and flat plate connection design. DOT National Transportation Integrated Search 2016-01-01 This project investigates the cause(s) of premature deterioration of MoDOT finger plate and flat plate expansion devices : under high traffic volumes and then uses that information to design new Load and Resistance Factor Design (LRFD) : finger plate... 16. FRONT VIEW OF POURING FROM #61 HOLDING FURNACE AT #02 ... Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey FRONT VIEW OF POURING FROM #61 HOLDING FURNACE AT #02 STATION INTO THREE VERTICAL MOLDS SUBMERGED IN A WATER-FILLED TANK BELOW THE CASTING FLOOR. THE CASTING CREW'S JOBS DURING THIS PHASE OF THE OPERATION INCLUDE REGULATING THE POURING RATE AND MONITORING THE VALVE RODS THAT CONTROL THE WATER SPRAYS ON THE MOLDS. DIFFERENT ALLOYS REQUIRE SPECIFIC POURING SPEEDS AND WATER PRESSURES. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY 17. Alloy vapor deposition using ion plating and flash evaporation NASA Technical Reports Server (NTRS) Spalvins, T. 1971-01-01 Method extends scope of ion plating technique to include deposition of alloy films without changing composition of plating alloy. Coatings flow with specimen material without chipping or peeling. Technique is most effective vacuum deposition method for depositing alloys for strong and lasting adherence. 18. Detecting swift fox: Smoked-plate scent stations versus spotlighting Treesearch Daniel W. Uresk; Kieth E. Severson; Jody Javersak 2003-01-01 We compared two methods of detecting presence of swift fox: smoked-plate scent stations and spotlight counts. Tracks were counted on ten 1-mile (1.6-km) transects with bait/tracking plate stations every 0.1 mile (0.16 km). Vehicle spotlight counts were conducted on the same transects. Methods were compared with Spearman's rank order correlation. Repeated measures... 19. Ponderomotive phase plate for transmission electron microscopes DOEpatents Reed, Bryan W [Livermore, CA 2012-07-10 A ponderomotive phase plate system and method for controllably producing highly tunable phase contrast transfer functions in a transmission electron microscope (TEM) for high resolution and biological phase contrast imaging. The system and method includes a laser source and a beam transport system to produce a focused laser crossover as a phase plate, so that a ponderomotive potential of the focused laser crossover produces a scattering-angle-dependent phase shift in the electrons of the post-sample electron beam corresponding to a desired phase contrast transfer function. 20. 61. photographer unknown undated FIRST CONCRETE BEING POURED IN DRAFT ... Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey 61. photographer unknown undated FIRST CONCRETE BEING POURED IN DRAFT TUBE FLOOR SLAB. - Bonneville Project, Powerhouse No.1, Spanning Bradford Slough, from Bradford Island, Bonneville, Multnomah County, OR 1. HBA1c: clinical and biological agreement for standardization of assay methods. Report by the experts of ALFEDIAM (Association de Langue Française pour lEtude du Diabète et des Maladies Métabolique) and SFBC (Société Française de Biologie Clinique). PubMed Gillery, P; Bordas-Fonfrède, M; Chapelle, J P; Drouin, P; Hue, G; Lévy-Marchal, C; Périer, C; Sélam, J L; Slama, G; Thivolet, C; Vialettes, B 1999-09-01 Glycohaemoglobin, and particularly haemoglobin A1c(HbA1c), assays have been used for many years to retrospectively evaluate the glycaemic control of diabetic patients. Cut-off values have been established for deciding treatment modifications. The techniques used in the laboratories however exhibit varying quality, and all of them are not yet standardized. The consequence is an under-utilization of this test, especially in non-hospital practice. In this context, working groups of Société Française de Biologie Clinique (SFBC), Association de Langue Française pour l'Etude du Diabète et des Maladies Métaboliques (ALFEDIAM) and Société Française d'Endocrinologie (SFE) have met together, in order to analyze the national status, and to propose practical recommendations for implementing a standardization process on the basis of international experiences. It is recommended to exclusively express results as HbA1c percentage, using methods standardized and certified by comparison to reference methods such as those using Diabetes Control and Complications Trial (DCCT) values. Simultaneously, contacts have been established with manufacturers, and the realisation of periodic quality control surveys was encouraged. 2. OPTIMIZATION OF VOLTAMMETRIC METHODS FOR AN IN SITU DETERMINATION OF TOTAL SULFIDE IN ANOXIC POREWATER USING A MERCURY PLATED GOLD ELECTRODE EPA Science Inventory Voltammetric methods for determination of total sulfide concentrations in anoxic sediments utilizing a previously described [1] gold-based mercury amalgam microelectrode were optimized. Systematic studies in NaCl (supporting electrolyte) and porewater indicate variations in ionic... 3. Microchannel plate streak camera DOEpatents Wang, Ching L. 1989-01-01 An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays. 4. Bipolar battery plate NASA Technical Reports Server (NTRS) Rowlette, John J. (Inventor) 1985-01-01 A liquid-impermeable plate (10) having throughplate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with lead spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet. 5. Modelisation numerique de l'hydrologie pour l'aide a la gestion des bassins versants, par l'utilisation conjointe des systemes d'information geographique et de la methode des elements finis un nouvel outil pour le developpement durable SAGESS NASA Astrophysics Data System (ADS) Bel Hadj Kacem, Mohamed Salah All hydrological processes are affected by the spatial variability of the physical parameters of the watershed, and also by human intervention on the landscape. The water outflow from a watershed strictly depends on the spatial and temporal variabilities of the physical parameters of the watershed. It is now apparent that the integration of mathematical models into GIS's can benefit both GIS and three-dimension environmental models: a true modeling capability can help the modeling community bridge the gap between planners, scientists, decision-makers and end-users. The main goal of this research is to design a practical tool to simulate run-off water surface using Geographic design a practical tool to simulate run-off water surface using Geographic Information Systems and the simulation of the hydrological behavior by the Finite Element Method. 6. Grooved Armor Plate DTIC Science & Technology 1935-05-16 that many of the olateo tested do sux^ ass the reouired limita by a considerable margin. Therefore, the efficiency of these grooved plate...Plpte Thicknesn B>lll<tle .Llji^f - ./.. s... a’ ^ea:: of All RtSUltS !’ Teen of Rlgbeot lOf of All Reoultr. s/i«- 1830 an« 7/16" ?180 7. Armor Plate Ballistic Testing DTIC Science & Technology 1944-08-02 sistanoe to penotration characteristics. However, it is one of the most important factors involved, and when the type of steel , its soundness and its...this test and not to use it in comparing radically differdnt types of plates, such as steel and Dural. Such a comparison can be made only by examining...in many oases, For this reason it became necessary to develop an additional test for the oharaoteristio in rolled armor ( steel "soundness) and cast 8. Martian plate tectonics NASA Astrophysics Data System (ADS) Sleep, N. H. 1994-03-01 The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction occured beneath Arabia Terra and east dipping subduction beneath Tharsis Montes and Tempe Terra. Lineations associated with Gordii Dorsum are attributed to ridge-parallel structures, while Phelegra Montes and Scandia Colles are interpreted as transfer-parallel structures or ridge-fault-fault triple junction tracks. Other than for these few features, there is little topographic roughness in the lowlands. Seafloor spreading, if it occurred, must have been relatively rapid. Quantitative estimates of spreading rate are obtained by considering the physics of seafloor spreading in the lower (approx. 0.4 g) gravity of Mars, the absence of vertical scarps from age differences across fracture zones, and the smooth axial topography. Crustal thickness at a given potential temperature in the mantle source region scales inversely with gravity. Thus, the velocity of the rough-smooth transition for axial topography also scales inversely with gravity. Plate reorganizations where young crust becomes difficult to subduct are another constraint on spreading age. Plate tectonics, if it occurred, dominated the thermal and stress history of the planet. A geochemical implication is that the lower gravity of Mars allows deeper hydrothermal circulation through cracks and hence more hydration of oceanic crust so that more water is easily subducted than on the Earth. Age and structural relationships from photogeology as well as median wavelength gravity anomalies across the now dead breakup and subduction margins are the data most likely to test and modify hypotheses 9. Plated wire memory subsystem NASA Technical Reports Server (NTRS) Reynolds, L.; Tweed, H. 1972-01-01 The work performed entailed the design, development, construction and testing of a 4000 word by 18 bit random access, NDRO plated wire memory for use in conjunction with a spacecraft imput/output unit and central processing unit. The primary design parameters, in order of importance, were high reliability, low power, volume and weight. A single memory unit, referred to as a qualification model, was delivered. 10. Shoulder arthrodesis with a reconstruction plate PubMed Central Byeon, Hwa Kyo 2008-01-01 From 1995 to 2005, arthrodesis with a reconstruction plate was performed for eight shoulders. The average follow-up period was 44 months. The indications for shoulder arthrodesis were joint destruction as a sequel of tuberculous arthritis, malignant bone tumour, pyogenic arthritis, failed arthrodesis and paralysis of the brachial plexus. The evaluation criteria included bony union and pain. Two cases of malignant tumour required an homologous bone graft due to severe bone deficit—a fracture that occurred in the distal part of the arthrodesed shoulder after removing the plate. With the exception of these two cases, severe pain or other complications did not occur in any other case. Shoulder arthrodesis with a reconstruction plate was judged to be a useful method for glenohumeral salvage in cases without severe bone deficit. Further, additional treatment methods should be considered to prevent fracture that may occur as a result of severe bone deficit. PMID:18716728 11. Flow of nanofluid past a Riga plate NASA Astrophysics Data System (ADS) Ahmad, Adeel; Asghar, Saleem; Afzal, Sumaira 2016-03-01 This paper studies the mixed convection boundary layer flow of a nanofluid past a vertical Riga plate in the presence of strong suction. The mathematical model incorporates the Brownian motion and thermophoresis effects due to nanofluid and the Grinberg-term for the wall parallel Lorentz force due to Riga plate. The analytical solution of the problem is presented using the perturbation method for small Brownian and thermophoresis diffusion parameters. The numerical solution is also presented to ensure the reliability of the asymptotic method. The comparison of the two solutions shows an excellent agreement. The correlation expressions for skin friction, Nusselt number and Sherwood number are developed by performing linear regression on the obtained numerical data. The effects of nanofluid and the Lorentz force due to Riga plate, on the skin friction are discussed. 12. Comparative study of single lateral locked plating versus double plating in type C bicondylar tibial plateau fractures PubMed Central Neogi, Devdatta Suhas; Trikha, Vivek; Mishra, Kaushal Kant; Bandekar, Shivanand M.; Yadav, Chandra Shekhar 2015-01-01 Background: Bicondylar tibial plateau fractures are complex injuries and treatment is challenging. Ideal method is still controversial with risk of unsatisfactory results if not treated properly. Many different techniques of internal and external fixation are used. This study compares the clinical results in single locked plating versus dual plating (DP) using two incision approaches. Our hypothesis was that DP leads to less collapse and change in alignment at final followup compared with single plating. Materials and Methods: 61 cases of Type C tibial plateau fractures operated between January 2007 and June 2011 were included in this prospective study. All cases were operated either by single lateral locked plate by anterolateral approach or double plating through double incision. All cases were followed for a minimum of 24 months radiologically and clinically. The statistical analysis was performed using software SPSS 10.0 to analyze the data. Results: Twenty nine patients in a single lateral locked plate and 32 patients in a double plating group were followed for minimum 2 years. All fractures healed, however there was a significant incidence of malalignment in the single lateral plating group. Though there was a significant increase in soft tissue issues with the double plating group; however, there was only 3.12% incidence of deep infection. There was no significant difference in Hospital for special surgery score at 2 years followup. Conclusion: Double plating through two incisions resulted in a better limb alignment and joint reduction with an acceptable soft tissue complication rate. PMID:26015609 13. [Binding properties of components removable from dental base plate, analysed by Fourier-Transform Surface Plasmon Resonance (FT-SPR) method]. PubMed Bakó, József; Kelemen, Máté; Szalóki, Melinda; Vitályos, Géza; Radics, Tünde; Hegedüs, Csaba 2015-03-01 In parallel with the emergence of new dental materials the number of allergic diseases is continuously increasing. Extremely small quantities of the allergens are capable to inducing an allergic reaction. Therefore it is particularly important to examine these materials as antigens and investigate their binding properties to proteins (e.g. formaldehyde, methacrylic acid, benzoyl-peroxide...). The Fourier Transform Surface Plasmon Resonance Spectroscopy (FT-SPR) is a suitable examination method for this type of procedure. FT-SPR measurement is performed at a fixed angel of incident light, and reflectivity is measured over a range of wavelength in the near infrared. The advantages of this method are the outstanding sensitivity, the label-free detection capability and the possibility of the real-time testing procedure. Formaldehyde and methacrylic acid are among the most common dental allergens. In our study we examined these molecules by FT-SPR spectroscopy. The aim of this work was to investigate the suitability of this method to the detection of these materials, with special focuses on the analysis and evaluation concentration-dependent measurements. Different concentrations (0.01 %-0.2%) of formaldehyde and methacrylic acid solutions were measured. The individual spectra were measured for all of the solutions, and calibration curves were calculated for the materials for the possibility of the determination of an unknown concentration. The results confirmed that the method is theoretically capable to detect hundred-thousandths scale concentration-changes in the solution flowing above the SPR-chip. The concentration-dependent studies had proved that the method capable to measure directly these materials and can provide appropriate calibration for quantitative determination. These experiments show the broad applicability of the FT-SPR method, which can greatly facilitate the mapping and understanding of biomolecular interactions in the future. 14. Elastic Buckling of Orthotropic Plates Under Varying Axial Stresses NASA Technical Reports Server (NTRS) Badir, Ashraf; Hu, Hurang; Diallo, Abdouramane 1997-01-01 The elastic buckling load of simply supported rectangular orthotropic plates subjected to a second degree parabolic variation of axial stresses in the longitudinal direction is calculated using analytical methods. The variation of axial stresses is equilibrated by nonuniform shear stresses along the plate edges and transverse normal stresses. The influence of the aspect ratio is examined, and the results are compared with plates subjected to uniform axial stresses. 15. Fibonacci-like zone plate NASA Astrophysics Data System (ADS) Cheng, Shubo; Liu, Mengsi; Xia, Tian; Tao, Shaohua 2018-06-01 We present a new family of diffractive lenses, Fibonacci-like zone plates, generated with a modified Fibonacci sequence. The focusing properties and the evolution of transverse diffraction pattern for the Fibonacci-like zone plates have been analytically investigated both theoretically and experimentally and compared with the corresponding Fresnel zone plates of the same resolution. The results demonstrate that the Fibonacci-like zone plates possess the self-similar property and the multifocal behavior. Furthermore, the Fibonacci-like zone plate beams are found to possess the self-reconstruction property, and would be promising for 3D optical tweezers, laser machining, and optical imaging. 16. Symmetries in laminated composite plates NASA Technical Reports Server (NTRS) Noor, A. K. 1976-01-01 The different types of symmetry exhibited by laminated anisotropic fibrous composite plates are identified and contrasted with the symmetries of isotropic and homogeneous orthotropic plates. The effects of variations in the fiber orientation and the stacking sequence of the layers on the symmetries exhibited by composite plates are discussed. Both the linear and geometrically nonlinear responses of the plates are considered. A simple procedure is presented for exploiting the symmetries in the finite element analysis. Examples are given of square, skew and polygonal plates where use of symmetry concepts can significantly reduce the scope and cost of analysis. 17. The generalized mean zone plate NASA Astrophysics Data System (ADS) Xia, Tian; Cheng, Shubo; Tao, Shaohua 2018-06-01 In this paper a generalized mean zone plate is proposed, which generates twin foci located at the positions satisfying the expression of the generalized mean, which includes the m-golden mean, precious mean, and so on. The generalized mean zone plate can be designed to generate twin foci with various position ratios. The diffraction properties of the generalized mean zone plates have been investigated with simulations and experiments. The results show that the ratio of the positions of the twin foci for the generalized mean zone plate can be designed with the selected zone plate parameters. 18. Application of coordinate transform on ball plate calibration NASA Astrophysics Data System (ADS) Wei, Hengzheng; Wang, Weinong; Ren, Guoying; Pei, Limei 2015-02-01 For the ball plate calibration method with coordinate measurement machine (CMM) equipped with laser interferometer, it is essential to adjust the ball plate parallel to the direction of laser beam. It is very time-consuming. To solve this problem, a method based on coordinate transformation between machine system and object system is presented. With the fixed points' coordinates of the ball plate measured in the object system and machine system, the transformation matrix between the coordinate systems is calculated. The laser interferometer measurement data error due to the placement of ball plate can be corrected with this transformation matrix. Experimental results indicate that this method is consistent with the handy adjustment method. It avoids the complexity of ball plate adjustment. It also can be applied to the ball beam calibration. 19. An algorithm for full parametric solution of problems on the statics of orthotropic plates by the method of boundary states with perturbations NASA Astrophysics Data System (ADS) Penkov, V. B.; Ivanychev, D. A.; Novikova, O. S.; Levina, L. V. 2018-03-01 The article substantiates the possibility of building full parametric analytical solutions of mathematical physics problems in arbitrary regions by means of computer systems. The suggested effective means for such solutions is the method of boundary states with perturbations, which aptly incorporates all parameters of an orthotropic medium in a general solution. We performed check calculations of elastic fields of an anisotropic rectangular region (test and calculation problems) for a generalized plane stress state. 20. Compressive strength of damaged and repaired composite plates NASA Technical Reports Server (NTRS) Finn, Scott R.; He, Yi-Fei; Springer, George S.; Lee, Hung-Joo 1992-01-01 Tests were performed assessing the effectiveness of repair in restoring the mechanical properties of damaged, solid composite plates made either of Fiberite T300/976 graphite-epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, or ICI APC-2 graphite-PEEK. The plate length, the layup and the amount of damage were also varied. Damage was introduced in the plates either by impacting them with a solid projectile or by applying a transverse static load. Some (75 percent) or all (100 percent) of the damaged zone was then cut out, and the plate was repaired by plugging and patching the hole. The effectiveness of the repair was evaluated by measuring the compressive strengths of undamaged plates, damaged plates with no cutout, damaged plates with a cutout, and repaired plates. The data at an intermediate stage of repair provide information on the effect of each repair step on the compressive strength. The results indicated that for the solid plates used in these tests, the repair methods used herein did not improve the compressive strength of already damaged plates. 1. Principal visual word discovery for automatic license plate detection. PubMed Zhou, Wengang; Li, Houqiang; Lu, Yijuan; Tian, Qi 2012-09-01 License plates detection is widely considered a solved problem, with many systems already in operation. However, the existing algorithms or systems work well only under some controlled conditions. There are still many challenges for license plate detection in an open environment, such as various observation angles, background clutter, scale changes, multiple plates, uneven illumination, and so on. In this paper, we propose a novel scheme to automatically locate license plates by principal visual word (PVW), discovery and local feature matching. Observing that characters in different license plates are duplicates of each other, we bring in the idea of using the bag-of-words (BoW) model popularly applied in partial-duplicate image search. Unlike the classic BoW model, for each plate character, we automatically discover the PVW characterized with geometric context. Given a new image, the license plates are extracted by matching local features with PVW. Besides license plate detection, our approach can also be extended to the detection of logos and trademarks. Due to the invariance virtue of scale-invariant feature transform feature, our method can adaptively deal with various changes in the license plates, such as rotation, scaling, illumination, etc. Promising results of the proposed approach are demonstrated with an experimental study in license plate detection. 2. Hypervelocity impact on shielded plates NASA Technical Reports Server (NTRS) Smith, James P. 1993-01-01 A ballistic limit equation for hypervelocity impact on thin plates is derived analytically. This equation applies to cases of impulsive impact on a plate that is protected by a multi-shock shield, and it is valid in the range of velocity above 6 km/s. Experimental tests were conducted at the NASA Johnson Space Center on square aluminum plates. Comparing the center deflections of these plates with the theoretical deflections of a rigid-plastic plate subjected to a blast load, one determines the dynamic yield strength of the plate material. The analysis is based on a theory for the expansion of the fragmented projectile and on a simple failure criterion. Curves are presented for the critical projectile radius versus the projectile velocity, and for the critical plate thickness versus the velocity. These curves are in good agreement with curves that have been generated empirically. 3. Fuel cell end plate structure DOEpatents Guthrie, Robin J.; Katz, Murray; Schroll, Craig R. 1991-04-23 The end plates (16) of a fuel cell stack (12) are formed of a thin membrane. Pressure plates (20) exert compressive load through insulation layers (22, 26) to the membrane. Electrical contact between the end plates (16) and electrodes (50, 58) is maintained without deleterious making and breaking of electrical contacts during thermal transients. The thin end plate (16) under compressive load will not distort with a temperature difference across its thickness. Pressure plate (20) experiences a low thermal transient because it is insulated from the cell. The impact on the end plate of any slight deflection created in the pressure plate by temperature difference is minimized by the resilient pressure pad, in the form of insulation, therebetween. 4. AERIAL OF SHUTTLE LANDING FACILITY [SLF] POURING CONCRETE ON RUNWAY NASA Technical Reports Server (NTRS) 1975-01-01 AERIAL OF SHUTTLE LANDING FACILITY [SLF] POURING CONCRETE ON RUNWAY KSC-375C-10036.32 108-KSC-375C-10036.32, P-21425, ARCHIVE-04501 Aerial oblique of Shuttle Landing Facility. Pouring concrete on runway. Direction North - Altitude 100'. 5. [Conventional plate osteosynthesis]. PubMed Klaue, K 2010-02-01 Consolidation of bone is an essential clinical problem when treating fractures, fixing osteotomies and fusing joints. In most cases, the means of fixation are plates and screws. The goal is functional postoperative therapy by moving the adjacent joints and thus avoiding the deleterious disadvantages of long-lasting articular immobilization. Pre-operative planning, surgical approach, a good understanding of the precise mechanics of the structure and the biological answer for the various tissues are prerequisites of successful osteosynthesis. The choice of implants and the application of their versatility, as well as their adaptation to individual cases are the key to good results. 6. Light Armor Plate Development DTIC Science & Technology 1923-07-28 to thie time ot shipment will be ini- eluded, 06otioIjAs -- HistoT. On Dec ember 2S# lt~. uVeity -four plates -*ere raaivad fro* Watertown Are nal, Th...only AT .Jwi-ace Vvrl/ac e 914yramof specl .mens elsed for h7eat- treatment 12aiomArmor- P/ate Anyepstyatio,, Vi -oorner o! ogoii uipe’Aven va...tempering temperatures applied. Only oarburized specimens were suboted to the double- quenching treatment (see table IV). The purpose of this Waq to 7. Plated wire memory subsystem NASA Technical Reports Server (NTRS) Carpenter, K. H. 1974-01-01 The design, construction, and test history of a 4096 word by 18 bit random access NDRO Plated Wire Memory for use in conjunction with a spacecraft input/output and central processing unit is reported. A technical and functional description is given along with diagrams illustrating layout and systems operation. Test data is shown on the procedures and results of system level and memory stack testing, and hybrid circuit screening. A comparison of the most significant physical and performance characteristics of the memory unit versus the specified requirements is also included. 8. Designing Flat-Plate Photovoltaic Arrays NASA Technical Reports Server (NTRS) Ross, R. G., Jr. 1984-01-01 Report presents overview of state of art in design techniques for flat-plate solar photovoltaic modules and arrays. Paper discusses design requirements, design analyses, and test methods identified and developed for this technology over past several years in effort to reduce cost and improve utility and reliability for broad spectrum of terrestrial applications. 9. Oscillatory flow in a cone-and-plate bioreactor. PubMed Chung, C A; Tzou, M R; Ho, R W 2005-08-01 Motivated by biometric applications, we analyze oscillatory flow in a cone-and-plate geometry. The cone is rotated in a simple harmonic way on a stationary plate. Based on assuming that the angle between the cone and plate is small, we describe the flow analytically by a perturbation method in terms of two small parameters, the Womersley number and the Reynolds number, which account for the influences of the local acceleration and centripetal force, respectively. Working equations for the shear stresses induced both by laminar primary and secondary flows on the plate surface are presented. 10. Physical optics for oven-plate scattering prediction NASA Technical Reports Server (NTRS) Baldauf, J.; Lambert, K. 1991-01-01 An oven assembly design is described, which will be used to determine the effects of temperature on the electrical properties of materials which are used as coatings for metal plates. Experimentally, these plates will be heated to a very high temperature in the oven assembly, and measured using a microwave reflectance measurement system developed for the NASA Lewis Research Center, Near-Field Facility. One unknown in this measurement is the effect that the oven assembly will have on the reflectance properties of the plate. Since the oven will be much larger than the plate, the effect could potentially be significant as the size of the plate becomes smaller. Therefore, it is necessary to predict the effect of the oven on the measurement of the plate. A method for predicting the oven effect is described, and the theoretical oven effect is compared to experimental results of the oven material. The computer code which is used to predict the oven effect is also described. 11. Reduced dynamical model of the vibrations of a metal plate NASA Astrophysics Data System (ADS) Moreno, D.; Barrientos, Bernardino; Perez-Lopez, Carlos; Mendoza-Santoyo, Fernando; Guerrero, J. A.; Funes, M. 2005-02-01 The Proper Orthogonal Decomposition (POD) method is applied to the vibrations analysis of a metal plate. The data obtained from the metal plate under vibrations were measured with a laser vibrometer. The metal plate was subject to vibrations with an electrodynamical shaker in a range of frequencies from 100 to 5000 Hz. The deformation measurements were taken on a quarter of the plate in a rectangular grid of 7 x 8 points. The plate deformation measurements were used to calculate the eigenfunctions and the eigenvalues. It was found that a large fraction of the total energy of the deformation is contained within the first six POD modes. The essential features of the deformation are thus described by only the six first eigenfunctions. A reduced order model for the dynamical behavior is then constructed using Galerkin projection of the equation of motion for the vertical displacement of a plate. 12. Comparative study of single lateral locked plating versus double plating in type C bicondylar tibial plateau fractures. PubMed Neogi, Devdatta Suhas; Trikha, Vivek; Mishra, Kaushal Kant; Bandekar, Shivanand M; Yadav, Chandra Shekhar 2015-01-01 Bicondylar tibial plateau fractures are complex injuries and treatment is challenging. Ideal method is still controversial with risk of unsatisfactory results if not treated properly. Many different techniques of internal and external fixation are used. This study compares the clinical results in single locked plating versus dual plating (DP) using two incision approaches. Our hypothesis was that DP leads to less collapse and change in alignment at final followup compared with single plating. 61 cases of Type C tibial plateau fractures operated between January 2007 and June 2011 were included in this prospective study. All cases were operated either by single lateral locked plate by anterolateral approach or double plating through double incision. All cases were followed for a minimum of 24 months radiologically and clinically. The statistical analysis was performed using software SPSS 10.0 to analyze the data. Twenty nine patients in a single lateral locked plate and 32 patients in a double plating group were followed for minimum 2 years. All fractures healed, however there was a significant incidence of malalignment in the single lateral plating group. Though there was a significant increase in soft tissue issues with the double plating group; however, there was only 3.12% incidence of deep infection. There was no significant difference in Hospital for special surgery score at 2 years followup. Double plating through two incisions resulted in a better limb alignment and joint reduction with an acceptable soft tissue complication rate. 13. CAD-CAM plates versus conventional fixation plates for primary mandibular reconstruction: A biomechanical in vitro analysis. PubMed Rendenbach, Carsten; Sellenschloh, Kay; Gerbig, Lucca; Morlock, Michael M; Beck-Broichsitter, Benedicta; Smeets, Ralf; Heiland, Max; Huber, Gerd; Hanken, Henning 2017-11-01 CAD/CAM reconstruction plates have become a viable option for mandible reconstruction. The aim of this study was to determine whether CAD/CAM plates provide higher fatigue strength compared with conventional fixation systems. 1.0 mm miniplates, 2.0 mm conventional locking plates (DePuy Synthes, Umkirch, Germany), and 2.0 mm CAD/CAM plates (Materialise, Leuven, Belgium/DePuy Synthes) were used to reconstruct a polyurethane mandible model (Synbone, Malans, CH) with cortical and cancellous bone equivalents. Mastication was simulated via cyclic dynamic testing using a universal testing machine (MTS, Bionix, Eden Prairie, MN, USA) until material failure reached a rate of 1 Hz with increasing loads on the left side. No significant difference was found between the groups until a load of 300 N. At higher loads, vertical displacement differed increasingly, with a poorer performance of miniplates (p = 0.04). Plate breakage occurred in miniplates and conventional locking plates. Screw breakage was recorded as the primary failure mechanism in CAD/CAM plates. Stiffness was significantly higher with the CAD/CAM plates (p = 0.04). CAD/CAM plates and reconstruction plates provide higher fatigue strength than miniplates, and stiffness is highest in CAD/CAM systems. All tested fixation methods seem sufficiently stable for mandible reconstruction. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved. 14. Numerical solution of acoustic scattering by finite perforated elastic plates PubMed Central 2016-01-01 We present a numerical method to compute the acoustic field scattered by finite perforated elastic plates. A boundary element method is developed to solve the Helmholtz equation subjected to boundary conditions related to the plate vibration. These boundary conditions are recast in terms of the vibration modes of the plate and its porosity, which enables a direct solution procedure. A parametric study is performed for a two-dimensional problem whereby a cantilevered perforated elastic plate scatters sound from a point quadrupole near the free edge. Both elasticity and porosity tend to diminish the scattered sound, in agreement with previous work considering semi-infinite plates. Finite elastic plates are shown to reduce acoustic scattering when excited at high Helmholtz numbers k0 based on the plate length. However, at low k0, finite elastic plates produce only modest reductions or, in cases related to structural resonance, an increase to the scattered sound level relative to the rigid case. Porosity, on the other hand, is shown to be more effective in reducing the radiated sound for low k0. The combined beneficial effects of elasticity and porosity are shown to be effective in reducing the scattered sound for a broader range of k0 for perforated elastic plates. PMID:27274685 15. Numerical solution of acoustic scattering by finite perforated elastic plates. PubMed Cavalieri, A V G; Wolf, W R; Jaworski, J W 2016-04-01 We present a numerical method to compute the acoustic field scattered by finite perforated elastic plates. A boundary element method is developed to solve the Helmholtz equation subjected to boundary conditions related to the plate vibration. These boundary conditions are recast in terms of the vibration modes of the plate and its porosity, which enables a direct solution procedure. A parametric study is performed for a two-dimensional problem whereby a cantilevered perforated elastic plate scatters sound from a point quadrupole near the free edge. Both elasticity and porosity tend to diminish the scattered sound, in agreement with previous work considering semi-infinite plates. Finite elastic plates are shown to reduce acoustic scattering when excited at high Helmholtz numbers k 0 based on the plate length. However, at low k 0 , finite elastic plates produce only modest reductions or, in cases related to structural resonance, an increase to the scattered sound level relative to the rigid case. Porosity, on the other hand, is shown to be more effective in reducing the radiated sound for low k 0 . The combined beneficial effects of elasticity and porosity are shown to be effective in reducing the scattered sound for a broader range of k 0 for perforated elastic plates. 16. Dual fuel gradients in uranium silicide plates SciTech Connect Pace, B.W. 1997-08-01 Babcock & Wilcox has been able to achieve dual gradient plates with good repeatability in small lots of U{sub 3}Si{sub 2} plates. Improvements in homogeneity and other processing parameters and techniques have allowed the development of contoured fuel within the cladding. The most difficult obstacles to overcome have been the ability to evaluate the bidirectional fuel loadings in comparison to the perfect loading model and the different methods of instilling the gradients in the early compact stage. The overriding conclusion is that to control the contour of the fuel, a known relationship between the compact, the frames and final coremore » gradient must exist. Therefore, further development in the creation and control of dual gradients in fuel plates will involve arriving at a plausible gradient requirement and building the correct model between the compact configuration and the final contoured loading requirements.« less 17. A unified theory for laminated plates NASA Astrophysics Data System (ADS) Guiamatsia Tafeuvoukeng, Irene A literature survey on plate and beam theories show how the advent of the finite element method and the variational method circa 1940 have been a great stimulant for the research in this field. The initial thin plate formulation has been incrementally expanded to treat the isotropic thick plate, the anisotropic single layer, and then laminated plates. It appears however that current formulations still fall into one of two categories: (1) The formulation is tailored for a specific laminate and/or loading case; (2) or the formulation is too complicated to be of practical relevance. In this work a new unifying approach to laminated plate formulation is presented. All laminated plates, including sandwich panels, subjected to any surface load and with any boundary conditions are treated within a single model. In addition, the fundamental behavior of the plate as a two-dimensional structural element is explained. The novel idea is the introduction of fundamental state solutions, which are analytical far field stress and strain solutions of the laminated plate subjected to a set of hierarchical primary loads, the fundamental loads. These loads are carefully selected to form a basis of the load space, and corresponding solutions are superposed to obtain extremely accurate predictions of the three dimensional solution. six,y,z =aklx,y sikl z where i = 1,..., 6; 1=1,...,l max is a substate of the kth fundamental state k=1,2,3,... Typically, a fundamental state solution is expressed as a through-thickness function (z), while the amplitudes of each fundamental load are found from two dimensional finite element solution as a function of in-plane coordinates (x,y). Three major contributions are produced in this work: (1) A complete calibration of the plate as a two-dimensional structure is performed with pure bending and constant shear fundamental states. (2) There are four independent ways to apply a constant shear resultant on a plate, as opposed to one for a beam. This makes 18. Angular stable lateral plating is a valid alternative to conventional plate fixation in the proximal phalanx. A biomechanical study. PubMed Shanmugam, R; Ernst, M; Stoffel, K; Fischer, M F; Wahl, D; Richards, R G; Gueorguiev, B 2015-06-01 Dorsal plating is commonly used in proximal phalanx fractures but it bears the risk of interfering with the extensor apparatus. In this study, dorsal and lateral plating fixation methods are compared to assess biomechanical differences using conventional 1.5mm non-locking plates and novel 1.3mm lateral locking plates. Twenty-four fresh frozen human cadaveric proximal phalanges were equally divided into four groups. An osteotomy was set at the proximal metaphyseal-diaphyseal junction and fixed with either dorsal (group A) or lateral (group B) plating using a 1.5mm non-locking plate, or lateral plating with a novel 1.3mm locking plate with bicortical (group C) or unicortical (group D) screws. The specimens were loaded in axial, dorsovolar and mediolateral direction to assess fixation stiffness followed by a cyclic destructive test in dorsovolar loading direction. Axial stiffness was highest in group D (mean 321.02, SEM 21.47N/mm) with a significant difference between groups D and B (P=0.033). Locking plates (groups C and D) were stiffer than non-locking plates under mediolateral loading (P=0.007), no significant differences were noted under dorsovolar loading. Furthermore, no significant differences were observed under cyclic loading to failure between any of the study groups. No considerable biomechanical advantage of using a conventional 1.5mm dorsal non-locking plate was identified over the novel 1.3mm lateral locking plate in the treatment of proximal phalanx fractures. Since the novel low-profile plate is less disruptive to the extensor mechanism, it should be considered as a valid alternative. Copyright © 2015 Elsevier Ltd. All rights reserved. 19. Process for protecting bonded components from plating shorts DOEpatents Tarte, Lisa A.; Bonde, Wayne L.; Carey, Paul G.; Contolini, Robert J.; McCarthy, Anthony M. 2000-01-01 A method which protects the region between a component and the substrate onto which the components is bonded using an electrically insulating fillet of photoresist. The fillet protects the regions from subsequent plating with metal and therefore shorting the plated conductors which run down the sides of the component and onto the substrate. 20. Stresses and strains in thick perforated orthotropic plates Treesearch A. Alshaya; John Hunt; R. Rowlands 2016-01-01 Stress and strain concentrations and in-plane and out-of-plane stress constraint factors associated with a circular hole in thick, loaded orthotropic composite plates are determined by three-dimensional finite element method. The plate has essentially infinite in-plane geometry but finite thickness. Results for Sitka Spruce wood are emphasized, although some for carbon... 1. Methode de calcul a N-corps basee sur la G0W0: Etude du couplage electron-phonon dans le C60 et developpement d'une approche acceleree pour materiaux organiques NASA Astrophysics Data System (ADS) Laflamme Janssen, Jonathan This thesis studies the limitations of density functional theory. These limits are explored in the context of a traditional implementation using a plane waves basis set. First, we investigate the limit of the size of the systems that can be treated. Cutting edge methods that assess these limitations are then used to simulate nanoscale systems. More specifically, the grafting of bromophenyl molecules on the sidewall of carbon nanotubes is studied with these methods, as a better understanding of this procedure could have substantial impact on the electronic industry. Second, the limitations of the precision of density functional theory are explored. We begin with a quantitative study of the uncertainty of this method for the case of electron-phonon coupling calculations and find it to be substantially higher than what is widely presumed in the literature. The uncertainty on electronphonon coupling calculations is then explored within the G0W0 method, which is found to be a substantially more precise alternative. However, this method has the drawback of being severely limitated in the size of systems that can be computed. In the following, theoretical solutions to overcome these limitations are developed and presented. The increased performance and precision of the resulting implementation opens new possibilities for the study and design of materials, such as superconductors, polymers for organic photovoltaics and semiconductors. Keywords: Condensed matter physics, ab initio calculations, density functional theory, nanotechnology, carbon nanotubes, many-body perturbation theory, G0W0 method.. 2. From Plate Tectonic to Continental Dynamics NASA Astrophysics Data System (ADS) Molnar, P. H. 2017-12-01 By the early 1970s, the basics of plate tectonics were known. Although much understanding remained to be gained, as a topic of research, plate tectonics no longer defined the forefront of earth science. Not only had it become a foundation on which to build, but also the methods used to reveal it became tools to take in new directions. For me as a seismologist studying earthquakes and active processes, the deformation of continents offered an obvious topic to pursue. Obviously examining the deformation of continents and ignoring the widespread geologic evidence of both ongoing and finite deformation of crust would be stupid. I was blessed with the opportunity to learn from and collaborate with two of the best, Paul Tapponnier and Clark Burchfiel. Continental deformation differed from plate tectonics both because deformation was widespread but more importantly because crust shortens (extends) horizontally and thickens (thins), processes that can be ignored where plate tectonics - the relative motion of rigid plates - occurs. Where a plate boundary passes into a continent, not only must the forces that move plates do work against friction or other dissipative processes, but where high terrain is created, they must also do work against gravity, to create gravitational potential energy in high terrain. Peter Bird and Kenneth Piper and Philip England and Dan McKenzie showed that a two-dimensional thin viscous sheet with vertically averaged properties enabled both sources of resistance to be included without introducing excessive complexity and to be scaled by one dimensionless number, what the latter pair called the Argand number. Increasingly over the past thirty years, emphasis has shifted toward the role played by the mantle lithosphere, because of both its likely strength and its negative buoyancy, which makes it gravitationally unstable. Despite progress since realizing that rigid plates (the essence of plate tectonics) provides a poor description of continental 3. Numerical Study of Impingement Location of Liquid Jet Poured from a Tilting Ladle with Lip Spout NASA Astrophysics Data System (ADS) Castilla, R.; Gamez-Montero, P. J.; Raush, G.; Khamashta, M.; Codina, E. 2017-04-01 A new approach for simulating liquid poured from a tilting lip spout is presented, using neither a dynamic mesh nor the moving solid solution method. In this case only the tilting ladle is moving, so we propose to rotate the gravitational acceleration at an angular velocity prescribed by a geometrical and dynamical calculation to keep the poured flow rate constant. This angular velocity is applied to modify the orientation of the gravity vector in computational fluid dynamics (CFD) simulations using the OpenFOAM® toolbox. Also, fictitious forces are considered. The modified solver is used to calculate the impingement location for six spout geometries and compare the jet dispersion there. This method could offer an inexpensive tool to calculate optimal spout geometries to reduce sprue size in the metal casting industry. 4. Characteristics of the Footprints of Field Lines for Variable Location of Plate for a Single-Null Divertor Tokamak with the Effects of Dipole Coil Using Method of Maps NASA Astrophysics Data System (ADS) Burton, Joni; Ali, Halima; Punjabi, Alkesh 1996-11-01 We determine the properties of the footprint of the magnetic field lines from the stochastic scrape-off layer of a single-null divertor tokamak including the effects of an externally placed dipole coil as the location of the divertor plate is varied. We use the Method of Maps (Punjabi A, Verma A and Boozer A, Phys Rev Lett), 69, 3322 (1992) and J Plasma Phys, 52, 91 (1994) for this investigation. The unperturbed magnetic topology is represented by the Symmetric Simple Map (Ali H, Watson M, Mayer C, Punjabi A and Boozer A, Bull Am Phys Soc), 40, 1855 (1995). The effects of the dipole coil are repesented by the Dipole Map (Ali H, Watson M, Punjabi A and Boozer A, Sherwood Mtg), paper 1C20 (1996). A single dipole coil is placed across from the X-point below the last good surface. The area of the footprint is calculated using the method of fractal dimesion. This work is supported by US DOE OFES. Joni Burton is an undergraduate mathematics major at Hampton University. She is a Ronald E. McNair Scholar at HU supported by R. E. McNair Foundation. 5. Tectonics of the Easter plate NASA Technical Reports Server (NTRS) Engeln, J. F.; Stein, S. 1984-01-01 A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used. 6. Caracterisation thermique de modules de refroidissement pour la photovoltaique concentree NASA Astrophysics Data System (ADS) Collin, Louis-Michel Pour rentabiliser la technologie des cellules solaires, une reduction du cout d'exploitation et de fabrication est necessaire. L'utilisation de materiaux photovoltaiques a un impact appreciable sur le prix final par quantite d'energie produite. Une technologie en developpement consiste a concentrer la lumiere sur les cellules solaires afin de reduire cette quantite de materiaux. Or, concentrer la lumiere augmente la temperature de la cellule et diminue ainsi son efficacite. Il faut donc assurer a la cellule un refroidissement efficace. La charge thermique a evacuer de la cellule passe au travers du recepteur, soit la composante soutenant physiquement la cellule. Le recepteur transmet le flux thermique de la cellule a un systeme de refroidissement. L'ensemble recepteur-systeme de refroidissement se nomme module de refroidissement. Habituellement, la surface du recepteur est plus grande que celle de la cellule. La chaleur se propage donc lateralement dans le recepteur au fur et a mesure qu'elle traverse le recepteur. Une telle propagation de la chaleur fournit une plus grande surface effective, reduisant la resistance thermique apparente des interfaces thermiques et du systeme de refroidissement en aval vers le module de refroidissement. Actuellement, aucune installation ni methode ne semble exister afin de caracteriser les performances thermiques des recepteurs. Ce projet traite d'une nouvelle technique de caracterisation pour definir la diffusion thermique du recepteur a l'interieur d'un module de refroidissement. Des indices de performance sont issus de resistances thermiques mesurees experimentalement sur les modules. Une plateforme de caracterisation est realisee afin de mesurer experimentalement les criteres de performance. Cette plateforme injecte un flux thermique controle sur une zone localisee de la surface superieure du recepteur. L'injection de chaleur remplace le flux thermique normalement fourni par la cellule. Un systeme de refroidissement est installe 7. A Qualitative Case Study Approach To Examine Information Resources Management. (Utilisation d'une Approche Qualitative par Methode de cas pour Etudier la Gestion des Ressources D'information). ERIC Educational Resources Information Center Bergeron, Pierrette 1997-01-01 Illustrates how a qualitative approach was used to study the complex and poorly defined concept of information resources management. Explains the general approach to data collection, its advantages and limitations, and the process used to analyze the data. Presents results, along with lessons learned through using method. (Author/AEF) 8. Multiple plate hydrostatic viscous damper NASA Technical Reports Server (NTRS) Ludwig, L. P. (Inventor) 1981-01-01 A device for damping radial motion of a rotating shaft is described. The damper comprises a series of spaced plates extending in a radial direction. A hydraulic piston is utilized to place a load in these plates. Each annular plate is provided with a suitable hydrostatic bearing geometry on at least one of its faces. This structure provides a high degree of dampening in a rotor case system of turbomachinery in general. The damper is particularly useful in gas turbine engines. 9. Ion plating for the future NASA Technical Reports Server (NTRS) Spalvins, T. 1981-01-01 The ion plating techniques are classified relative to the instrumental set up, evaporation media and mode of transport. Distinction is drawn between the low vacuum (plasma) and high vacuum (ion beam) techniques. Ion plating technology is discussed at the fundamental and industrial level. At the fundamental level, the capabilities and limitations of the plasma (evaporant flux) and film characteristics are evaluated. On the industrial level, the performance and potential uses of ion plated films are discussed. 10. Ion plating for the future NASA Technical Reports Server (NTRS) Spalvins, T. 1981-01-01 The ion plating techniques are classified relative to the instrumental set up, evaporation media, and mode of transport. A distinction is drawn between the low vacuum (plasma) and high vacuum (ion beam) techniques. Ion plating technology is discussed at the fundamental and industrial level. At the fundamental level, the capabilities and limitations of the plasma (evaporant flux) and film characteristics are evaluated. And on the industrial level, the performance and potential uses of ion plated films are discussed. 11. Channel plate for DNA sequencing DOEpatents Douthart, R.J.; Crowell, S.L. 1998-01-13 This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface. 15 figs. 12. Optical Near-Field Plates DTIC Science & Technology 2015-04-08 AFRL-OSR-VA-TR-2015-0085 OPTICAL NEAR-FILED PLATES Roberto Merlin UNIVERSITY OF MICHIGAN Final Report 04/08/2015 DISTRIBUTION A: Distribution...03-2015 Final 09/01/2009-12/31/2014 Optical Near-Field Plates FA9550-09-1-0636 erlin, Roberto, D. The University of Michigan Ann Arbor, MI 48109...distribution unlimited Optical near-field plates were designed using antisymmetric plasmon modes to generate abrupt phase changes within a fraction of a 13. Intermittent plate tectonics? PubMed Silver, Paul G; Behn, Mark D 2008-01-04 Although it is commonly assumed that subduction has operated continuously on Earth without interruption, subduction zones are routinely terminated by ocean closure and supercontinent assembly. Under certain circumstances, this could lead to a dramatic loss of subduction, globally. Closure of a Pacific-type basin, for example, would eliminate most subduction, unless this loss were compensated for by comparable subduction initiation elsewhere. Given the evidence for Pacific-type closure in Earth's past, the absence of a direct mechanism for termination/initiation compensation, and recent data supporting a minimum in subduction flux in the Mesoproterozoic, we hypothesize that dramatic reductions or temporary cessations of subduction have occurred in Earth's history. Such deviations in the continuity of plate tectonics have important consequences for Earth's thermal and continental evolution. 14. Plating Bacteriophage M13. PubMed Green, Michael R; Sambrook, Joseph 2017-10-03 A plaque of bacteriophage M13 derives from infection of a single bacterium by a single virus particle. The progeny particles infect neighboring bacteria, which, in turn, release another generation of daughter virus particles. If the bacteria are growing in semisolid medium (e.g., containing agar or agarose), then the diffusion of the progeny particles is limited. Cells infected with bacteriophage M13 are not killed, but have a longer generation time than uninfected Escherichia coli In consequence, plaques appear as areas of slower-growing cells on a faster-growing lawn of bacterial cells. This protocol describes plating of bacteriophage M13 stocks. Plaques are readily detectable on top agar after 4-8 h of incubation at 37°C. © 2017 Cold Spring Harbor Laboratory Press. 15. Development of a high-throughput method based on thin-film microextraction using a 96-well plate system with a cork coating for the extraction of emerging contaminants in river water samples. PubMed Morés, Lucas; Dias, Adriana Neves; Carasek, Eduardo 2018-02-01 In this study, a new method was developed in which a biosorbent material is used as the extractor phase in conjunction with a recently described sample preparation technique called thin-film microextraction and a 96-well plate system. The method was applied for the determination of emerging contaminants, such as 3-(4-methylbenzylidene) camphor, ethylparaben, triclocarban, and bisphenol A in water samples. The separation and detection of the analytes were performed by high-performance liquid chromatography with diode array detection. These contaminants are considered hazardous to human health and other living beings. Thus, the development of an analytical method to determine these compounds is of great interest. The extraction parameters were evaluated using multivariate and univariate optimization techniques. The optimum conditions for the method were 3 h of extraction time, 20 min of desorption with 300 μL of acetonitrile and methanol (50:50, v/v), and the addition of 5% w/v sodium chloride to the sample. The analytical figures of merit showed good results with linear correlation coefficients higher than 0.99, relative recoveries of 72-125%, interday precision (n = 3) of 4-18%, and intraday precision (n = 9) of 1-21%. The limit of detection was 0.3-5.5 μg/L, and the limit of quantification was 0.8-15 μg/L. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. 16. Analysis and comparison of focused ion beam milling and vibratory polishing sample surface preparation methods for porosity study of U-Mo plate fuel for research and test reactors. PubMed Westman, Bjorn; Miller, Brandon; Jue, Jan-Fong; Aitkaliyeva, Assel; Keiser, Dennis; Madden, James; Tucker, Julie D 2018-07-01 Uranium-Molybdenum (U-Mo) low enriched uranium (LEU) fuels are a promising candidate for the replacement of high enriched uranium (HEU) fuels currently in use in a high power research and test reactors around the world. Contemporary U-Mo fuel sample preparation uses focused ion beam (FIB) methods for analysis of fission gas porosity. However, FIB possess several drawbacks, including reduced area of analysis, curtaining effects, and increased FIB operation time and cost. Vibratory polishing is a well understood method for preparing large sample surfaces with very high surface quality. In this research, fission gas porosity image analysis results are compared between samples prepared using vibratory polishing and FIB milling to assess the effectiveness of vibratory polishing for irradiated fuel sample preparation. Scanning electron microscopy (SEM) imaging was performed on sections of irradiated U-Mo fuel plates and the micrographs were analyzed using a fission gas pore identification and measurement script written in MatLab. Results showed that the vibratory polishing method is preferentially removing material around the edges of the pores, causing the pores to become larger and more rounded, leading to overestimation of the fission gas porosity size. Whereas, FIB preparation tends to underestimate due to poor micrograph quality and surface damage leading to inaccurate segmentations. Despite the aforementioned drawbacks, vibratory polishing remains a valid method for porosity analysis sample preparation, however, improvements should be made to reduce the preferential removal of material surrounding pores in order to minimize the error in the porosity measurements. Copyright © 2018 Elsevier Ltd. All rights reserved. 17. True Shear Parallel Plate Viscometer NASA Technical Reports Server (NTRS) Ethridge, Edwin; Kaukler, William 2010-01-01 This viscometer (which can also be used as a rheometer) is designed for use with liquids over a large temperature range. The device consists of horizontally disposed, similarly sized, parallel plates with a precisely known gap. The lower plate is driven laterally with a motor to apply shear to the liquid in the gap. The upper plate is freely suspended from a double-arm pendulum with a sufficiently long radius to reduce height variations during the swing to negligible levels. A sensitive load cell measures the shear force applied by the liquid to the upper plate. Viscosity is measured by taking the ratio of shear stress to shear rate. 18. Glass-bead peen plating NASA Technical Reports Server (NTRS) Graves, J. R. 1974-01-01 Peen plating of aluminum, copper, and nickel powders was investigated. Only aluminum was plated successfully within the range of peen plating conditions studied. Optimum plating conditions for aluminum were found to be: (1) bead/powder mixture containing 25 to 35% powder by weight, (2) peening intensity of 0.007A as measured by Almen strip, and (3) glass impact bead diameter of at least 297 microns (0.0117 inches) for depositing-100 mesh aluminum powder. No extensive cleaning or substrate preparation is required beyond removing loose dirt or heavy oil. 19. Laser-driven flyer plate DOEpatents Paisley, Dennis L. 1991-01-01 Apparatus for producing high velocity flyer plates involving placing a layer of dielectric material between a first metal foil and a second metal foil. With laser irradiation through an optical substrate, the first metal foil forms a plasma in the area of the irradiation, between the substrate and the solid portion of the first metal foil. When the pressure between the substrate and the foil reaches the stress limit of the dielectric, the dielectric will break away and launch the flyer plate out of the second metal foil. The mass of the flyer plate is controlled, as no portion of the flyer plate is transformed into a plasma. 20. Accurate Simulation of Acoustic Emission Sources in Composite Plates NASA Technical Reports Server (NTRS) Prosser, W. H.; Gorman, M. R. 1994-01-01 Acoustic emission (AE) signals propagate as the extensional and flexural plate modes in thin composite plates and plate-like geometries such as shells, pipes, and tubes. The relative amplitude of the two modes depends on the directionality of the source motion. For source motions with large out-of-plane components such as delaminations or particle impact, the flexural or bending plate mode dominates the AE signal with only a small extensional mode detected. A signal from such a source is well simulated with the standard pencil lead break (Hsu-Neilsen source) on the surface of the plate. For other sources such as matrix cracking or fiber breakage in which the source motion is primarily in-plane, the resulting AE signal has a large extensional mode component with little or no flexural mode observed. Signals from these type sources can also be simulated with pencil lead breaks. However, the lead must be fractured on the edge of the plate to generate an in-plane source motion rather than on the surface of the plate. In many applications such as testing of pressure vessels and piping or aircraft structures, a free edge is either not available or not in a desired location for simulation of in-plane type sources. In this research, a method was developed which allows the simulation of AE signals with a predominant extensional mode component in composite plates requiring access to only the surface of the plate. 1. Operative Cost Comparison: Plating Versus Intramedullary Fixation for Clavicle Fractures. PubMed Hanselman, Andrew E; Murphy, Timothy R; Bal, George K; McDonough, E Barry 2016-09-01 Although clavicle fractures often heal well with nonoperative management, current literature has shown improved outcomes with operative intervention for specific fracture patterns in specific patient types. The 2 most common methods of midshaft clavicle fracture fixation are intramedullary and plate devices. Through retrospective analysis, this study performed a direct cost comparison of these 2 types of fixation at a single institution over a 5-year period. Outcome measures included operative costs for initial surgery and any hardware removal surgeries. This study reviewed 154 patients (157 fractures), and of these, 99 had intramedullary fixation and 58 had plate fixation. A total of 80% (79 of 99) of intramedullary devices and 3% (2 of 58) of plates were removed. Average cost for initial intramedullary placement was2955 (US dollars) less than that for initial plate placement (P<.001); average cost for removal was $1874 less than that for plate removal surgery (P=.2). Average total cost for all intramedullary surgeries was$1392 less than the average cost for all plating surgeries (P<.001). Average cost for all intramedullary surgeries requiring plate placement and removal was \$653 less than the average cost for all plating surgeries that involved only placement (P=.04). Intramedullary fixation of clavicle fractures resulted in a statistically significant cost reduction compared with plate fixation, despite the incidence of more frequent removal surgeries. [Orthopedics.2016; 39(5):e877-e882.]. Copyright 2016, SLACK Incorporated.
2. The Importance of Lower Mantle Structure to Plate Stresses and Plate Motions
Holt, W. E.; Wang, X.; Ghosh, A.
2016-12-01
Plate motions and plate stresses are widely assumed as the surface expression of mantle convection. The generation of plate tectonics from mantle convection has been studied for many years. Lithospheric thickening (or ridge push) and slab pull forces are commonly accepted as the major driving forces for the plate motions. However, the importance of the lower mantle to plate stresses and plate motions remains less clear. Here, we use the joint modeling of lithosphere and mantle dynamics approach of Wang et al. (2015) to compute the tractions originating from deeper mantle convection and follow the method of Ghosh et al. (2013) to calculate gravitational potential energy per unit area (GPE) based on Crust 1.0 (Laske et al., 2013). Absolute values of deviatoric stresses are determined by the body force distributions (GPE gradients and traction magnitudes applied at the base of the lithosphere). We use the same relative viscosity model that Ghosh et al. (2013) used, and we solve for one single adjustable scaling factor that multiplies the entire relative viscosity field to provide absolute values of viscosity throughout the lithosphere. This distribution of absolute values of lithosphere viscosities defines the magnitudes of surface motions. In this procedure, the dynamic model first satisfies the internal constraint of no-net-rotation of motions. The model viscosity field is then scaled by the single factor until we achieve a root mean square (RMS) minimum between computed surface motions and the kinematic no-net-rotation (NNR) model of Kreemer et al. (2006). We compute plate stresses and plate motions from recently published global tomography models (over 70 based on Wang et al., 2015). We find that RMS misfits are significantly reduced when details of lower mantle structure from the latest tomography models are added to models that contain only upper and mid-mantle density distributions. One of the key reasons is that active upwelling from the Large Low Shear
3. Distal tibia fractures: locked or non-locked plating?
PubMed Central
Khalsa, Amrit S; Toossi, Nader; Tabb, Loni P; Amin, Nirav H; Donohue, Kenneth W; Cerynik, Douglas L
2014-01-01
Background and purpose Although plating is considered to be the treatment of choice in distal tibia fractures, controversies abound regarding the type of plating for optimal fixation. We conducted a systematic review to evaluate and compare the outcomes of locked plating and non-locked plating in treatment of distal tibia fractures. Patients and methods A systematic review was conducted using PubMed to identify articles on the outcomes of plating in distal tibia fractures that were published up to June 2012. We included English language articles involving a minimum of 10 adult cases with acute fractures treated using single-plate, minimally invasive techniques. Study-level binomial regression on the pooled data was conducted to determine the effect of locking status on different outcomes, adjusted for age, sex, and other independent variables. Results 27 studies met the inclusion criteria and were included in the final analysis of 764 cases (499 locking, 265 non-locking). Based on descriptive analysis only, delayed union was reported in 6% of cases with locked plating and in 4% of cases with non-locked plating. Non-union was reported in 2% of cases with locked plating and 3% of cases with non-locked plating. Comparing locked and non-locked plating, the odds ratio (OR) for reoperation was 0.13 (95% CI: 0.03–0.57) and for malalignment it was 0.10 (95% CI: 0.02–0.42). Both values were statistically significant. Interpretation This study showed that locked plating reduces the odds of reoperation and malalignment after treatment for acute distal tibia fracture. Future studies should accurately assess causality and the clinical and economic impact of these findings. PMID:24758325
4. Anomalous Buckling Characteristics of Laminated Metal-Matrix Composite Plates with Central Square Holes
NASA Technical Reports Server (NTRS)
Ko, William L.
1998-01-01
Compressive buckling analysis was performed on metal-matrix composite (MMC) plates with central square holes. The MMC plates have varying aspect ratios and hole sizes and are supported under different boundary conditions. The finite-element structural analysis method was used to study the effects of plate boundary conditions, plate aspect ratio, hole size, and the composite stacking sequence on the compressive buckling strengths of the perforated MMC plates. Studies show that by increasing the hole sizes, compressive buckling strengths of the perforated MMC plates could be considerably increased under certain boundary conditions and aspect ratios ("anomalous" buckling behavior); and that the plate buckling mode could be symmetrical or antisymmetrical, depending on the plate boundary conditions, aspect ratio, and the hole size. For same-sized plates with same-sized holes, the compressive buckling strengths of the perforated MMC plates with [90/0/0/90]2 lamination could be as much as 10 percent higher or lower than those of the [45/- 45/- 45/45]2 laminations, depending on the plate boundary conditions, plate aspect ratios, and the hole size. Clamping the plate edges induces far stronger "anomalous" buckling behavior (enhancing compressive buckling strengths at increasing hole sizes) of the perforated MMC plates than simply supporting the plate edges.
5. A MEMS square Chladni plate resonator
Pala, Sedat; Azgın, Kıvanç
2016-10-01
This paper presents the design, fabrication and tests of a micro-fabricated MEMS ‘Chladni’ plate resonator. The proposed MEMS resonator has a square plate geometry having a side length of 1400 µm and a height of 35 µm. Its geometry and electrode layout are designed to analyze and test as many modes as possible. The MEMS plate is fabricated using a silicon-on-insulator process with a 35 µm thick < \\text{1} \\text{1} \\text{1}> silicon layer on a glass substrate. Transverse vibration of the plate is investigated to obtain closed form natural frequencies and mode shapes, which are derived using the Rayleigh-Ritz energy method, with an electrostatic softening effect included. Closed form equations for the calculation of effective stiffness’, masses and natural frequencies of the two modes (mode (1,1) and mode (2,0)-(0,2)) are presented, with and without electrostatic softening. The analytical model is verified for those modes by finite-element simulations, frequency response tests in vacuum and laser Doppler vibrometer (LDV) experiments. The derived model deviates from the finite-element analysis by 3.35% for mode (1,1) and 6.15% for mode (2,0)-(0,2). For verification, the frequency responses of the plates are measured with both electrostatic excitation-detection at around 20 mTorr vacuum ambient and LDV at around 0.364 mTorr vacuum ambient. The resonance frequency and Q-factor of mode (1,1) are measured to be 104.2 kHz and 14 300, respectively. For mode (2,0)-(0,2), the measured resonance frequency and Q-factor are 156.68 kHz and 10 700, respectively. The presented LDV results also support both natural frequencies of interest and corresponding mode shapes of the plate structure.
6. Angular deformity correction by guided growth in growing children: Eight-plate versus 3.5-mm reconstruction plate.
PubMed
Park, Kyeong-Hyeon; Oh, Chang-Wug; Kim, Joon-Woo; Park, Il-Hyung; Kim, Hee-June; Choi, Young-Seo
2017-09-01
Guided growth using the eight-plate (8-plate) is the most commonly used method to correct angular deformities in children; however, implant failure has been reported. Recently, the 3.5-mm reconstruction plate (R-plate) has been used as an alternative option for guided growth; however, hardware prominence has been problematic. This study aimed to compare the coronal angular deformity correction results of guided growth between relatively thin 8-plates with cannulated screws and thick R-plates with solid screws. Thirty-nine physes (24 distal femoral, 15 proximal tibial) in 20 patients underwent hemiepiphysiodesis using 8-plates, and 61 physes (40 distal femoral, 21 proximal tibial) in 35 patients underwent hemiepiphysiodesis using R-plates. Coronal angular corrections were measured and compared preoperatively, and after the completion of corrections. Amounts and rates of correction and complications were compared between the groups. Mean body mass index was 18.7 kg/m2 in the 8-plate group, and 22.7 kg/m2 in the R-plate group. Angular correction was achieved in all deformities at a mean of 13.7 months and 19.7 months in the 8-plate and the R-plate group, respectively. The mean corrected mechanical lateral distal femoral angle was 9.0° in the 8-plate group, and 9.9° in the R-plate group (P = 0.55). The mean corrected medial proximal tibial angle was 7.1° in the 8-plate group, and 9.0° in the R-plate group (P = 0.07). The mean rates of angular correction were also not significantly different in the distal femur (1.03°/month vs. 0.77°/month, P = 0.2) and the proximal tibia (0.66°/month vs. 0.63°/month, P = 0.77). There was one superficial infection in each group, and one case of implant failure in the R-plate group. Two rebound deformities were observed and needed repeat hemiepiphysiodesis. Permanent physeal arrest was not observed in this series. Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
7. The concrete technology of post pouring zone of raft foundation of Hongyun Building B tower
Yin, Suhua; Yu, Liu; Wu, Yanli; Zhao, Ying
2017-08-01
The foundation of Hongyun building B tower is made of raft board foundation which is 3300mm in the thickness concreted pouring amount of large and the late poured band in the pouring settlement formed. The temperature of the pouring settlement was controlled in order to prevent the crack of the construction of the late poured band. The steel of post pouring band was designed and monitorred. The quality of post pouring band quality is guaranteed in the raft concrete foundation of Hongyun Building B tower.
8. [Case-control study on endobutton plate or clavicular hook plate for the repair of acromioclavicular joint dislocations].
PubMed
Zhu, Li; Yang, He-Jie; Zhao, Wan-Jun; Yang, Wu-Min; Zhou, Hui
2012-02-01
To compare the treatment results between Endobutton plate and clavicular hook plate for the treatment of acromioclavicular joint dislocations. From January 2009 to September 2010, 30 patients with acromioclavicular joint dislocations were treated with two different fixations: Endobutton plate (15 patients, including 12 males and 3 females, with a mean age of 38.5 +/- 8.2 years) and clavicular hook plate (15 patients, including 14 males and 1 female, with the mean age of 33.8 +/- 5.9 years). The mean operative time and blood loss were compared between the two groups. Joint function was assessed by the Karlsson standard. The mean operative time of the Endobutton group and the hook plate group were (61 +/- 8.6) min and (40 +/- 5.6) min. The average blood loss were (93 +/- 8.4) ml and (100 +/- 12.6) ml. There was no statistical difference between the two groups in the average blood loss and the mean operative time. According to the Karlsson standard, 13 patients got an excellent result, 2 good in the Endobutton group; and 7 patients got an excellent result and 7 good in hook plate group. The therapeutic effect in Endobutton group was better than that of hook plate group. In the treatment of acromioclavicular dislocation, fixation with Endobutton plate is believed to be better than hook plate fixation. It is an effective method for the repair of acromioclavicular joint dislocations in a short term. But its long term effects still need further follow up.
9. Clinical comparison between open plating and minimally invasive plate osteosynthesis for displaced proximal humeral fractures: A prospective randomized controlled trial.
PubMed
Sohn, Hoon-Sang; Jeon, Yoon Sang; Lee, JuHan; Shin, Sang-Jin
2017-06-01
10. Plate tectonics, damage and inheritance.
PubMed
Bercovici, David; Ricard, Yanick
2014-04-24
The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates.
11. APPARATUS FOR MELTING AND POURING METAL
DOEpatents
Harris, F.A.
1958-02-25
This patent relates to a crucible for melting and pouring a metal under controlled atmospheric conditions. The crucible has a frangible plug in the bottom and a retaining device to prevent the entrance of the broken portions of the plug into the mold without interfering with the flow of the melt. After the charge has been melted, a knockout rod is lowered through the charge and forced against the frangible plug sufficiently to break off the closure disk along a previously scored line. The disk drops onto a retaining grid large enough to permit the flow of metal around the disk and into the mold below. Thts arrangement elimnates the entry of broken portions of the plug into the mold, thereby elimnating a common cause of imperfect castings.
12. Vacuum fusion bonded glass plates having microstructures thereon
DOEpatents
Swierkowski, Steve P.; Davidson, James C.; Balch, Joseph W.
2001-01-01
An improved apparatus and method for vacuum fusion bonding of large, patterned glass plates. One or both glass plates are patterned with etched features such as microstructure capillaries and a vacuum pumpout moat, with one plate having at least one hole therethrough for communication with a vacuum pumpout fixture. High accuracy alignment of the plates is accomplished by a temporary clamping fixture until the start of the fusion bonding heat cycle. A complete, void-free fusion bond of seamless, full-strength quality is obtained through the plates; because the glass is heated well into its softening point and because of a large, distributed force that is developed that presses the two plates together from the difference in pressure between the furnace ambient (high pressure) and the channeling and microstructures in the plates (low pressure) due to the vacuum drawn. The apparatus and method may be used to fabricate microcapillary arrays for chemical electrophoresis; for example, any apparatus using a network of microfluidic channels embedded between plates of glass or similar moderate melting point substrates with a gradual softening point curve, or for assembly of glass-based substrates onto larger substrates, such as in flat panel display systems.
13. Dependence of the pour point of diesel fuels on the properties of the initial components
NASA Technical Reports Server (NTRS)
Ostashov, V. M.; Bobrovskiy, S. A.
1979-01-01
An analytical expression is obtained for the dependence of the pour point of diesel fuels on the pour point and weight relationship of the initial components. For determining the pour point of a multicomponent fuel mixture, it is assumed that the mixture of two components has the pour point of a separate equivalent component, then calculating the pour point of this equivalent component mixed with a third component, etc.
14. Fabrication par injection flexible de pieces coniques pour des applications aerospatiales
Shebib Loiselle, Vincent
Les materiaux composites sont presents dans les tuyeres de moteurs spatiaux depuis les annees soixante. Aujourd'hui, l'avenement des tissus tridimensionnels apporte une solution innovatrice au probleme de delamination qui limitait les proprietes mecaniques de ces composites. L'utilisation de ces tissus necessite toutefois la conception de procedes de fabrication mieux adaptes. Une nouvelle methode de fabrication de pieces composites pour des applications aerospatiales a ete etudiee tout au long de ce travail. Celle-ci applique les principes de l'injection flexible (procede Polyflex) a la fabrication de pieces coniques de fortes epaisseurs. La piece de validation a fabriquer represente un modele reduit de piece de tuyere de moteur spatial. Elle est composee d'un renfort tridimensionnel en fibres de carbone et d'une resine phenolique. La reussite du projet est definie par plusieurs criteres sur la compaction et la formation de plis du renfort et sur la formation de porosites de la piece fabriquee. Un grand nombre d'etapes ont ete necessaires avant la fabrication de deux pieces de validation. Premierement, pour repondre au critere sur la compaction du renfort, la conception d'un outil de caracterisation a ete entreprise. L'etude de la compaction a ete effectuee afin d'obtenir les informations necessaires a la comprehension de la deformation d'un renfort 3D axisymetrique. Ensuite, le principe d'injection de la piece a ete defini pour ce nouveau procede. Pour en valider les concepts proposes, la permeabilite du renfort fibreux ainsi que la viscosite de la resine ont du etre caracterisees. A l'aide de ces donnees, une serie de simulations de l'ecoulement pendant l'injection de la piece ont ete realisees et une approximation du temps de remplissage calculee. Apres cette etape, la conception du moule de tuyere a ete entamee et appuyee par une simulation mecanique de la resistance aux conditions de fabrication. Egalement, plusieurs outillages necessaires pour la fabrication
15. Impact damage of composite plates
NASA Technical Reports Server (NTRS)
Lal, K. M.; Goglia, G. L.
1983-01-01
A simple model to study low velocity transverse impact of thin plates made of fiber-reinforced composite material, in particular T300/5208 graphite-epoxy was discussed. This model predicts the coefficient of restitution, which is a measure of the energy absorbed by the target during an impact event. The model is constructed on the assumption that the plate is inextensible in the fiber direction and that the material is incompressible in the z-direction. Such a plate essentially deforms by shear, hence this model neglects bending deformations of the plate. The coefficient of restitution is predicted to increase with large interlaminar shear strength and low transverse shear modulus of the laminate. Predictions are compared with the test results of impacted circular and rectangular clamped plates. Experimentally measured values of the coefficient of restitution are found to agree with the predicted values within a reasonable error.
16. Present-day plate motions
NASA Technical Reports Server (NTRS)
Minster, J. B.; Jordan, T. H.
1977-01-01
A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to less than 3 My. A detailed comparison of RM2 with angular velocity vectors which best fit the data along individual plate boundaries indicates that RM2 performs close to optimally in most regions, with several notable exceptions. On the other hand, a previous estimate (RM1) failed to satisfy an extensive set of new data collected in the South Atlantic Ocean. It is shown that RM1 incorrectly predicts the plate kinematics in the South Atlantic because the presently available data are inconsistent with the plate geometry assumed in deriving RM1. It is demonstrated that this inconsistency can be remedied by postulating the existence of internal deformation with the Indian plate, although alternate explanations are possible.
17. The moving plate capacitor paradox
Davis, B. R.; Abbott, D.; Parrondo, J. M. R.
2000-03-01
For the first time we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. A demon restores the plates of the capacitor to their original position, only when the voltage across the capacitor is small—hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the question is how? We explore the concept of a moving plate capacitor, driven by noise, a step further by examining the case where the restoring force on the capacitor plates is provided by a simple spring, rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other.
18. SAMI Automated Plug Plate Configuration
Lorente, N. P. F.; Farrell, T.; Goodwin, M.
2013-10-01
The Sydney-AAO Multi-object Integral field spectrograph (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) which uses a plug-plate to mount its 13×61-core imaging fibre bundles (hexabundles) in the optical path at the telescope's prime focus. In this paper we describe the process of determining the positions of the plug-plate holes, where plates contain three or more stacked observation configurations. The process, which up until now has involved several separate processes and has required significant manual configuration and checking, is now being automated to increase efficiency and reduce error. This is carried out by means of a thin Java controller layer which drives the configuration cycle. This layer controls the user interface and the C++ algorithm layer where the plate configuration and optimisation is carried out. Additionally, through the Aladin display package, it provides visualisation and facilitates user verification of the resulting plates.
19. Performance optimization of plate heat exchangers with chevron plates
SciTech Connect
Muley, A.; Manglik, R.M.
1999-07-01
The enhanced heat transfer performance of a chevron plate heat exchanger (PHE) is evaluated employing (1) energy-conservation based performance evaluation criteria (PECs), and (2) the second-law based minimization of entropy generation principle. Single-phase laminar and turbulent flow convection for three different chevron-plate arrangements are considered. The influence of plate surface corrugation characteristics and their stack arrangements on the heat exchanger's thermal-hydraulic performance is delineated. Based on the different figures of merit, the results show that the extent of heat transfer enhancement increases with flow Re and chevron angle {beta} in laminar flow, but it diminishes with increasing Re in turbulentmore » flows. With up to 2.9 times higher Q, 48% lower A, and entropy generation number N{sub s,a} {lt} 1, relative to an equivalent flat-plate pack, chevron plates are found to be especially suitable in the low to medium flow rates range (20 {le} Re {le} 2,000). Also, there appears to be no significant advantage of using a mixed-plate over a symmetric-plate arrangement.« less
20. Balanced Orifice Plate
NASA Technical Reports Server (NTRS)
Kelley, Anthony R. (Inventor); Buskirk, Paul D. (Inventor)
2006-01-01
An orifice plate for use in a conduit through which fluid flows is defined by a central circular region having a radius R, and a ring-shaped region surrounding the central circular region. The ring-shaped region has holes formed therethrough with those holes centered at each radius R thereof satisfying a relationship A(sub R)=al(X(sub R)V(sub R)(sup b)) where A(sub R) is a sum of areas of those holes having centers at radius R, X(sub R) is a flow coefficient at radius R, V(sub R) is a velocity of the fluid that is to flow through the conduit at radius R, b is a constant selected to make at least one process variable (associated with the fluid that is to flow through the conduit) approximately equal at each radius R, and a is a constant that is equal to (X(sub R)A(sub R)V(sub R)(sup b)) at each radius R.
1. Electron microscopy of antigen precipitates extracted from gel diffusion plates
PubMed Central
Watson, D. H.; Le Bouvier, G. L.; Tomlinson, J. A.; Walkey, D. G. A.
1966-01-01
A method is described whereby material from virus precipitin lines from agar gel diffusion plates may be examined in the electron microscope by a negative staining technique. ImagesFIGS. 1-2FIGS. 3-4 PMID:4286708
2. A review and assessment of Virginia's license plate sheeting specifications.
DOT National Transportation Integrated Search
2003-01-01
At the request of Virginia's Secretary of Transportation, the Virginia Transportation Research Council undertook a review and assessment of Virginia's license plate sheeting specifications. The review was focused on the five test methods or specifica...
3. Plate equations for piezoelectrically actuated flexural mode ultrasound transducers.
PubMed
Perçin, Gökhan
2003-01-01
This paper considers variational methods to derive two-dimensional plate equations for piezoelectrically actuated flexural mode ultrasound transducers. In the absence of analytical expressions for the equivalent circuit parameters of a flexural mode transducer, it is difficult to calculate its optimal parameters and dimensions, and to choose suitable materials. The influence of coupling between flexural and extensional deformation, and coupling between the structure and the acoustic volume on the dynamic response of piezoelectrically actuated flexural mode transducer is analyzed using variational methods. Variational methods are applied to derive two-dimensional plate equations for the transducer, and to calculate the coupled electromechanical field variables. In these methods, the variations across the thickness direction vanish by using the stress resultants. Thus, two-dimensional plate equations for a stepwise laminated circular plate are obtained.
4. Mantle convection with plates and mobile, faulted plate margins.
PubMed
Zhong, S; Gurnis, M
1995-02-10
A finite-element formulation of faults has been incorporated into time-dependent models of mantle convection with realistic rheology, continents, and phase changes. Realistic tectonic plates naturally form with self-consistent coupling between plate and mantle dynamics. After the initiation of subduction, trenches rapidly roll back with subducted slabs temporarily laid out along the base of the transition zone. After the slabs have penetrated into the lower mantle, the velocity of trench migration decreases markedly. The inhibition of slab penetration into the lower mantle by the 670-kilometer phase change is greatly reduced in these models as compared to models without tectonic plates.
5. Métamatériaux pour la protection sismique
Guenneau, Sébastien; Enoch, Stefan; Colombi, Andrea; Roux, Philippe; Brule, Stéphane
2018-02-01
Les physiciens des ondes élaborent des modèles théoriques et numériques pour un contrôle accru de la lumière dans des matériaux structurés à l'échelle nanométrique et s'en inspirent pour contrôler les ondes mécaniques de Rayleigh dans des sols structurés à l'échelle métrique, avec des trous dans un sol ou des arbres en surface savamment agencés. Un transfert de paradigme s'opère entre les métamatériaux électromagnétiques pour la photonique et les métamatériaux sismiques pour le génie civil.
6. POURING IRON FROM ELECTRIC FURNACE INTO BULL LADLE AFTER MAGNESIUM ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
POURING IRON FROM ELECTRIC FURNACE INTO BULL LADLE AFTER MAGNESIUM HAD BEEN ADDED TO GENERATE DUCTILE IRON WHEN IT COOLS IN THE MOLD. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL
7. 60. photographer unknown undated CONCRETE BEING POURED ON CENTER PORTION ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
60. photographer unknown undated CONCRETE BEING POURED ON CENTER PORTION OF DRAFT TUBE FLOOR SLAB. - Bonneville Project, Powerhouse No.1, Spanning Bradford Slough, from Bradford Island, Bonneville, Multnomah County, OR
8. POURING FOOTING OF PIER #1. View is to the southwest, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
POURING FOOTING OF PIER #1. View is to the southwest, looking from Pier 2 in Trinity County toward Pier 1 in Humboldt County - South Fork Trinity River Bridge, State Highway 299 spanning South Fork Trinity River, Salyer, Trinity County, CA
9. 42. Casting floor, "B" furnace, pour in progress; mudgun is ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
42. Casting floor, "B" furnace, pour in progress; mudgun is to right of furnace; operator takes temperature of iron in trough during pout. Looking south - Rouge Steel Company, 3001 Miller Road, Dearborn, MI
10. 6. VIEW LOOKING WEST FROM THE POURING AISLE OF THE ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
6. VIEW LOOKING WEST FROM THE POURING AISLE OF THE ELECTRIC FURNACE BUILDING AT ELECTRIC FURNACE X-3. - U.S. Steel Duquesne Works, Electric Furnace Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA
11. INTERIOR VIEW WITH LADLE POURING MOLTEN IRON INTO QBOP FURNACE. ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
INTERIOR VIEW WITH LADLE POURING MOLTEN IRON INTO Q-BOP FURNACE. - U.S. Steel, Fairfield Works, Q-Bop Furnace, North of Valley Road & West of Ensley, Pleasant Grove Road, Fairfield, Jefferson County, AL
12. Optomechanical study and optimization of cantilever plate dynamics
Furlong, Cosme; Pryputniewicz, Ryszard J.
1995-06-01
Optimum dynamic characteristics of an aluminum cantilever plate containing holes of different sizes and located at arbitrary positions on the plate are studied computationally and experimentally. The objective function of this optimization is the minimization/maximization of the natural frequencies of the plate in terms of such design variable s as the sizes and locations of the holes. The optimization process is performed using the finite element method and mathematical programming techniques in order to obtain the natural frequencies and the optimum conditions of the plate, respectively. The modal behavior of the resultant optimal plate layout is studied experimentally through the use of holographic interferometry techniques. Comparisons of the computational and experimental results show that good agreement between theory and test is obtained. The comparisons also show that the combined, or hybrid use of experimental and computational techniques complement each other and prove to be a very efficient tool for performing optimization studies of mechanical components.
13. Fabricating cooled electronic system with liquid-cooled cold plate and thermal spreader
SciTech Connect
Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.
Methods are provided for facilitating cooling of an electronic component. The method includes providing a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to bemore » cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.« less
14. Fabricating cooled electronic system with liquid-cooled cold plate and thermal spreader
SciTech Connect
Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.
Methods are provided for facilitating cooling of an electronic component. The methods include providing a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to bemore » cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.« less
15. Rectangular Shell Plating Under Uniformly Distributed Hydrostatic Pressure
NASA Technical Reports Server (NTRS)
Neubert, M; Sommer, A
1940-01-01
A check of the calculation methods used by Foppl and Henky for investigating the reliability of shell plating under hydrostatic pressure has proved that the formulas yield practical results within the elastic range of the material. Foppl's approximate calculation leaves one on the safe side. It further was found on the basis of the marked ductility of the shell plating under tensile stress that the strength is from 50 to 100 percent higher in the elastic range than expected by either method.
16. Vibration analysis of partially cracked plate submerged in fluid
Soni, Shashank; Jain, N. K.; Joshi, P. V.
2018-01-01
The present work proposes an analytical model for vibration analysis of partially cracked rectangular plates coupled with fluid medium. The governing equation of motion for the isotropic plate based on the classical plate theory is modified to accommodate a part through continuous line crack according to simplified line spring model. The influence of surrounding fluid medium is incorporated in the governing equation in the form of inertia effects based on velocity potential function and Bernoulli's equations. Both partially and totally submerged plate configurations are considered. The governing equation also considers the in-plane stretching due to lateral deflection in the form of in-plane forces which introduces geometric non-linearity into the system. The fundamental frequencies are evaluated by expressing the lateral deflection in terms of modal functions. The assessment of the present results is carried out for intact submerged plate as to the best of the author's knowledge the literature lacks in analytical results for submerged cracked plates. New results for fundamental frequencies are presented as affected by crack length, fluid level, fluid density and immersed depth of plate. By employing the method of multiple scales, the frequency response and peak amplitude of the cracked structure is analyzed. The non-linear frequency response curves show the phenomenon of bending hardening or softening and the effect of fluid dynamic pressure on the response of the cracked plate.
17. Statistical Analyses of Femur Parameters for Designing Anatomical Plates.
PubMed
Wang, Lin; He, Kunjin; Chen, Zhengming
2016-01-01
Femur parameters are key prerequisites for scientifically designing anatomical plates. Meanwhile, individual differences in femurs present a challenge to design well-fitting anatomical plates. Therefore, to design anatomical plates more scientifically, analyses of femur parameters with statistical methods were performed in this study. The specific steps were as follows. First, taking eight anatomical femur parameters as variables, 100 femur samples were classified into three classes with factor analysis and Q-type cluster analysis. Second, based on the mean parameter values of the three classes of femurs, three sizes of average anatomical plates corresponding to the three classes of femurs were designed. Finally, based on Bayes discriminant analysis, a new femur could be assigned to the proper class. Thereafter, the average anatomical plate suitable for that new femur was selected from the three available sizes of plates. Experimental results showed that the classification of femurs was quite reasonable based on the anatomical aspects of the femurs. For instance, three sizes of condylar buttress plates were designed. Meanwhile, 20 new femurs are judged to which classes the femurs belong. Thereafter, suitable condylar buttress plates were determined and selected.
18. Details: Elevation of Plate Typical Bay, SectionThrough Plate Typical Bay, ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Details: Elevation of Plate Typical Bay, Section-Through Plate Typical Bay, Section-Through Plate Center Bay, Elevation of Plate Center Bay - Contoocook Covered Bridge, Spanning Contoocook River, Hopkinton, Merrimack County, NH
19. Reconstructing plate motion paths where plate tectonics doesn't strictly apply
Handy, M. R.; Ustaszewski, K.
2012-04-01
consistency between crustal shortening estimates and the amount of subducted lithosphere imaged at depth. This approach has several limitations: (1) shortening values in mountain belts are usually minimum estimates due to the erosion of deformational fronts and out-of-sequence thrusting that obscure or even eliminate zones of shortening. Also, subduction may occur without accretion of material to the upper plate; (2) sedimentary ages are often loosely bracketed and only high-retentivity isotopic systems yield ages near the age of mineral formation in metamorphic rocks; (3) images of seismic velocity anomalies are highly model-dependent and the anomalies themselves may have been partly lost to thermal erosion, especially in areas that have experienced heating, for example, beneath extensional basins. Thus, only a few orogens studied so far (e.g., the circum-Mediterreanean belts) have the density of geological and geophysical data needed to constrain the translation of a sufficient number of reference points to obtain a reliable plate-motion vector. Nevertheless, this approach complements established methods for determining plate motion (plate-circuits using paleomagnetic information, ocean-floor magnetic lineaments) and provides a viable alternative where such paleomagnetic information is sparse or lacking.
20. Inclusion of transverse shear deformation in exact buckling and vibration analysis of composite plate assemblies
NASA Technical Reports Server (NTRS)
Anderson, Melvin S.; Kennedy, David
1992-01-01
The problem considered is the development of the necessary plate stiffnesses for use in a general purpose program for buckling and vibration of composite plate assemblies. The required stiffnesses are for the assumption of sinusoidal response along the plate length with transverse shear included. The method is based on the exact solution of the plate differential equations for a composite laminate having fully populated A, B, and D matrices which leads to a differential equation of tenth order.
1. Improvement of rolling 6 mm thin plates in plate rolling mill PT. Krakatau Posco
Pujiyanto, Hamdani
2017-01-01
A 6-mm thin plate is difficult to produce especially if the product requires wide size and high strength. Flatness is the main quality issue in rolling 6-mm plate using a 4-high reversing mill which use ±1100-mm work roll. Thus some methods are applied to overcome such issue in order to comply to customer quality requirement. Pre-rolling, rolling, and post-rolling conditions have to be considered comprehensively. Roll unit management will be the key factor before rolling condition. The roll unit itself has a significant impact on work roll crown wearness in relation with work roll intial crown and thermal crown. Work roll crown along with the modification of hydraulic gap control (HGC) could directly alter the flatness of the plate.
2. Surface Detail Reproduction and Dimensional Stability of Contemporary Irreversible Hydrocolloid Alternatives after Immediate and Delayed Pouring
PubMed Central
Kusugal, Preethi; Chourasiya, Ritu Sunil; Ruttonji, Zarir; Astagi, Preeti; Nayak, Ajay Kumar; Patil, Abhishekha
2018-01-01
Purpose: To overcome the poor dimensional stability of irreversible hydrocolloids, alternative materials were introduced. The dimensional changes of these alternatives after delayed pouring are not well studied and documented in the literature. The purpose of the study is to evaluate and compare the surface detail reproduction and dimensional stability of two irreversible hydrocolloid alternatives with an extended-pour irreversible hydrocolloid at different time intervals. Materials and Methods: All testing were performed according to the ANSI/ADA specification number 18 for surface detail reproduction and specification number 19 for dimensional change. The test materials used in this study were newer irreversible hydrocolloid alternatives such as AlgiNot FS, Algin-X Ultra FS, and Kromopan 100 which is an extended pour irreversible hydrocolloid as control. The surface detail reproduction was evaluated using stereomicroscope. The dimensional change after storage period of 1 h, 24 h, and 120 h was assessed and compared between the test materials and control. The data were analyzed using one-way ANOVA and post hoc Bonferroni test. Results: Statistically significant results (P < 0.001) were seen when mean scores of the tested materials were compared with respect to reproduction of 22 μm line from the metal block. Kromopan 100 showed statistically significant differences between different time intervals (P < 0.001) and exhibited more dimensional change. Algin-X Ultra FS proved to be more accurate and dimensionally stable. Conclusions: Newer irreversible hydrocolloid alternative impression materials were more accurate in surface detail reproduction and exhibited minimal dimensional change after storage period of 1 h, 24 h, and 120 h than extended-pour irreversible hydrocolloid impression material. PMID:29599578
3. A new portable vibrator for plaster pouring: effect on the marginal fit at cylinder-abutment
PubMed Central
de ANDRADE, Pâmela Cândida Aires Ribas; LUTHI, Leonardo Flores; STANLEY, Kyle; CARDOSO, Antônio Carlos
2012-01-01
Objective The aim of this study was to test a new portable vibrator for plaster pouring (developed for this purpose), comparing the effect of its use on the accuracy of working cast of implant-supported restorations to the conventional vibrator. Material and methods From a master cast with 2 implants, 30 transfer moldings were made randomly and divided into three groups: Group I (GI): pouring performed in an outsourced dental laboratory with conventional plaster vibrator (10 casts), Group II (GII): pouring performed in the laboratory of the Federal University of Santa Catarina (UFSC) with conventional plaster vibrator (10 casts) and Group III (GIII): pouring performed with the portable vibrator fabricated for this study (10 casts). The position of the analogue and marginal adaptation of the infrastructure were verified by testing the single screw on the master model and on the working model. The measurement of misfit was blindly performed with a precision microscope and analyzing unit, Quadra-Check 200. The data were statistically analyzed by analysis of variance (ANOVA) and the Holm-Sidak test (α=0.05). Results Means±standard deviations were as follows: GI: 19.19±4.73 µm; GII: 21.72±5.41 µm; GIII: 13.5±2.39 µm (P<0.05), with GIII significantly lower as compared to the other groups. Conclusion Within the limitations of this study, it was concluded that a greater accuracy of working cast was achieved when a portable vibrator was used for casting molds. PMID:23138736
DOEpatents
Wiencek, Thomas C.; Domagala, Robert F.; Thresh, Henry R.
1990-01-01
Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pair of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat having a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process.
Saburi, T.; Yoshida, M.; Kubota, S.
2017-02-01
The dynamic strain distribution of a fiber re-enforced plastic (FRP) plate under blast loading was investigated using a Digital Image Correlation (DIC) image analysis method. The testing FRP plates were mounted in parallel to each other on a steel frame. 50 g of composition C4 explosive was used as a blast loading source and set in the center of the FRP plates. The dynamic behavior of the FRP plate under blast loading were observed by two high-speed video cameras. The set of two high-speed video image sequences were used to analyze the FRP three-dimensional strain distribution by means of DIC method. A point strain profile extracted from the analyzed strain distribution data was compared with a directly observed strain profile using a strain gauge and it was shown that the strain profile under the blast loading by DIC method is quantitatively accurate.
6. Optimum structural design with plate bending elements - A survey
NASA Technical Reports Server (NTRS)
1981-01-01
A survey is presented of recently published papers in the field of optimum structural design of plates, largely with respect to the minimum-weight design of plates subject to such constraints as fundamental frequency maximization. It is shown that, due to the availability of powerful computers, the trend in optimum plate design is away from methods tailored to specific geometry and loads and toward methods that can be easily programmed for any kind of plate, such as finite element methods. A corresponding shift is seen in optimization from variational techniques to numerical optimization algorithms. Among the topics covered are fully stressed design and optimality criteria, mathematical programming, smooth and ribbed designs, design against plastic collapse, buckling constraints, and vibration constraints.
7. HETEROTROPHIC PLATE COUNT (HPC) METHODOLOGY IN THE UNITED STATES
EPA Science Inventory
ABSTRACT
In the United States (U.S.), the history of bacterial plate counting methods used for water can be traced largely through Standard Methods for the Examination of Water and Wastewater (Standard Methods). The bacterial count method has evolved from the original St...
8. License plate recognition (phase B).
DOT National Transportation Integrated Search
2010-06-01
License Plate Recognition (LPR) technology has been used for off-line automobile enforcement purposes. The technology has seen mixed success with correct reading rate as high as 60 to 80% depending on the specific application and environment. This li...
9. Carbon-assisted flyer plates
DOEpatents
Stahl, D.B.; Paisley, D.L.
1994-04-12
A laser driven flyer plate is described utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited. 2 figures.
10. Optical measurements of flyer plate acceleration by emulsion explosive
Kubota, Shiro; Shimada, Hideki; Matsui, Kikuo; Ogata, Yuji; Seto, Masahiro; Masui, Akira; Wada, Yuji; Liu, Zhi-Yue; Itoh, Shigeru
2001-04-01
This paper presents the study on the application of explosive welding technique to the field of the urgent repair of the gas and water pipe networks. The essential parameters related to the explosive welding are scrutinized from the point of view of the minimizing the damage to the steel pipe after welded explosively with a flyer plate. The emulsion explosive is contained in a rectangular hard-paper box whose bottom is the flyer plate with 100 mm length, 25 mm width and 1.5 mm thickness. The flyer motions of the flyer plates accelerated by emulsion explosive are observed by high-speed photography from the side and front view of the flyer plate. The damage to the pipe by the flyer plate is discussed with the results of the observation of flyer motion and explosive welding test under various experimental conditions. Moreover, one way to control the motion of the flyer plate is proposed. We put a PMMA buffer block into the explosive. The flying process of flyer plate is calculated by the finite different scheme based on the ALE method. The effectiveness of this method is demonstrated by the experimental and numerical studies.
11. Algorithmes et architectures pour ordinateurs quantiques supraconducteurs
Blais, Alexandre
Depuis sa formulation, la theorie de l'information a ete basee, implicitement, sur les lois de la physique classique. Une telle formulation est toutefois incomplete puisqu'elle ne tient pas compte de la realite quantique. Au cours des vingt dernieres annees, l'expansion de la theorie de l'information englobant les effets purement quantiques a connu un interet grandissant. La realisation d'un systeme de traitement de l'information quantique, un ordinateur quantique, presente toutefois de nombreux defis. Dans ce document, on s'interesse a differents aspects concernant ces defis. On commence par presenter des concepts algorithmiques comme l'optimisation de calculs quantiques et le calcul quantique geometrique. Par la suite, on s'interesse au design et a differents aspects de l'utilisation de qubits bases sur les jonctions Josephson. En particulier, un nouveau design de qubit supraconducteur est suggere. On presente aussi une approche originale pour l'interaction entre qubits. Cette approche est tres generale puisqu'elle peut etre appliquee a differents designs de qubits. Finalement, on s'interesse a la lecture des qubits supraconducteurs de flux. Le detecteur suggere ici a l'avantage de pouvoir etre decouple du qubit lorsqu'il n'y a pas de mesure en cours.
12. An Online Intervention Comparing a Very Low-Carbohydrate Ketogenic Diet and Lifestyle Recommendations Versus a Plate Method Diet in Overweight Individuals With Type 2 Diabetes: A Randomized Controlled Trial.
PubMed
Saslow, Laura R; Mason, Ashley E; Kim, Sarah; Goldman, Veronica; Ploutz-Snyder, Robert; Bayandorian, Hovig; Daubenmier, Jennifer; Hecht, Frederick M; Moskowitz, Judith T
2017-02-13
Type 2 diabetes is a prevalent, chronic disease for which diet is an integral aspect of treatment. In our previous trial, we found that recommendations to follow a very low-carbohydrate ketogenic diet and to change lifestyle factors (physical activity, sleep, positive affect, mindfulness) helped overweight people with type 2 diabetes or prediabetes improve glycemic control and lose weight. This was an in-person intervention, which could be a barrier for people without the time, flexibility, transportation, social support, and/or financial resources to attend. The aim was to determine whether an online intervention based on our previous recommendations (an ad libitum very low-carbohydrate ketogenic diet with lifestyle factors; "intervention") or an online diet program based on the American Diabetes Associations' "Create Your Plate" diet ("control") would improve glycemic control and other health outcomes among overweight individuals with type 2 diabetes. In this pilot feasibility study, we randomized overweight adults (body mass index ≥25) with type 2 diabetes (glycated hemoglobin [HbA 1c ] 6.5%-9.0%) to a 32-week online intervention based on our previous recommendations (n=12) or an online diet program based around a plate method diet (n=13) to assess the impact of each intervention on glycemic control and other health outcomes. Primary and secondary outcomes were analyzed by mixed-effects linear regression to compare outcomes by group. At 32 weeks, participants in the intervention group reduced their HbA 1c levels more (estimated marginal mean [EMM] -0.8%, 95% CI -1.1% to -0.6%) than participants in the control group (EMM -0.3%, 95% CI -0.6% to 0.0%; P=.002). More than half of the participants in the intervention group (6/11, 55%) lowered their HbA 1c to less than 6.5% versus 0% (0/8) in the control group (P=.02). Participants in the intervention group lost more weight (EMM -12.7 kg, 95% CI -16.1 to -9.2 kg) than participants in the control group (EMM -3.0 kg
13. New technical tip for anterior cervical plating : make hole first and choose the proper plate size later.
PubMed
Park, Jeong Yoon; Zhang, Ho Yeol; Oh, Min Chul
2011-04-01
It is well known that plate-to-disc distance (PDD) is closely related to adjacent-level ossification following anterior cervical plate placement. The study was undertaken to compare the outcomes of two different anterior cervical plating methods for degenerative cervical condition. Specifically, the new method involves making holes for plate screws first with an air drill and then choosing a plate size. The other method was standard, that is, decide on the plate size first, locate the plate on the anterior vertebral body, and then drilling the screw holes. Our null hypothesis was that the new technical tip may increase PDD as compared with the standard anterior cervical plating procedure. We retrospectively reviewed 49 patients who had a solid fusion after anterior cervical arthrodesis with a plate for the treatment of cervical disc degeneration. Twenty-three patients underwent the new anterior cervical plating technique (Group A) and 26 patients underwent the standard technique (Group B). PDD and ratios between PDD to anterior body heights (ABH) were measured using postoperative lateral radiographs. In addition, operating times and clinical results were reviewed in all cases. The mean durations of follow-up were 16.42±5.99 (Group A) and 19.83±6.71 (Group B) months, range 12 to 35 months. Of these parameters mentioned above, cephalad PDD (5.43 versus 3.46 mm, p=0.005) and cephalad PDD/ABH (0.36 versus 0.23, p=0.004) were significantly greater in the Group A, whereas operation time for two segment arthrodesis (141.9 versus 170.6 minutes, p=0.047) was significantly lower in the Group A. There were no significant difference between the two groups in caudal PDD (5.92 versus 5.06 mm), caudal PDD/ABH (0.37 versus 0.32) and clinical results. The new anterior cervical plating method represents an improvement over the standard method in terms of cephalad plate-to-disc distance and operating time.
14. A new license plate extraction framework based on fast mean shift
Pan, Luning; Li, Shuguang
2010-08-01
License plate extraction is considered to be the most crucial step of Automatic license plate recognition (ALPR) system. In this paper, a region-based license plate hybrid detection method is proposed to solve practical problems under complex background in which existing large quantity of disturbing information. In this method, coarse license plate location is carried out firstly to get the head part of a vehicle. Then a new Fast Mean Shift method based on random sampling of Kernel Density Estimate (KDE) is adopted to segment the color vehicle images, in order to get candidate license plate regions. The remarkable speed-up it brings makes Mean Shift segmentation more suitable for this application. Feature extraction and classification is used to accurately separate license plate from other candidate regions. At last, tilted license plate regulation is used for future recognition steps.
15. Natural Vibration Analysis of Clamped Rectangular Orthotropic Plates
dalaei, m.; kerr, a. d.
The natural vibrations of clamped rectangular orthotropic plates are analyzed using the extended Kantorovich method. The developed iterative scheme converges very rapidly to the final result. The obtained natural frequencies are evaluated for a square plate made of Kevlar 49 Epoxy and the obtained results are compared with those published by Kanazawa and Kawai, and by Leissa. The agreement was found to be very close. As there are no exact analytical solutions for clamped rectangular plates, the generated closed form expression for the natural modes, and the corresponding natural frequencies, are very suitable for use in engineering analyses.
16. Analysis of Piezoelectric Actuator for Vibration Control of Composite plate
Gomaa, Ahmed R.; Hai, Huang
2017-07-01
Vibration analysis is studied numerically in this paper for a simply supported composite plate subjected to external loadings. Vibrations are controlled by using piezoelectric patches. Finite element method (ANSYS) is used for obtaining finite element model of the smart plate structure, a layered composite plate is manufactured experimentally and tested to obtain the structure mechanical properties. Different piezoelectric patch areas and different applied gain voltage effects on vibration attenuation is studied. The numerical solution is compared with the experimental work, a good agreement achieved.
17. Fabrication and testing of scatter plates for interferometry
NASA Technical Reports Server (NTRS)
Pour, J. J., Sr.; Pitts, J. R.
1972-01-01
Scatter plate interferometry has become a reliable method of measuring surface configurations of telescope mirrors and other optical components. The scatter plate used in an instrument should be of optimum quality if the surface it is being used to measure is to be of high accuracy. Tests were performed and results show that, although many scatter plates would function, few were of the optimum quality necessary. These few were of the 180 grit group, using 35- and 30-s exposures, which are figures derived from calculations.
18. Transfer function modeling of damping mechanisms in viscoelastic plates
NASA Technical Reports Server (NTRS)
Slater, J. C.; Inman, D. J.
1991-01-01
This work formulates a method for the modeling of material damping characteristics in plates. The Sophie German equation of classical plate theory is modified to incorporate hysteresis effects represented by complex stiffness using the transfer function approach proposed by Golla and Hughes, (1985). However, this procedure is not limited to this representation. The governing characteristic equation is decoupled through separation of variables, yielding a solution similar to that of undamped classical plate theory, allowing solution of the steady state as well as the transient response problem.
19. Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component
DOEpatents
Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.
2016-04-05
Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.
20. Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component
SciTech Connect
Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.
Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface tomore » be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.« less
1. Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component
DOEpatents
Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.
2016-08-09
Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.
2. Recommended Practices for Measurement of Gas Path Pressures and Temperatures for Performance Assessment of Aircraft Turbine Engines and Components (Les Methodes Recommandees pour la Mesure de la Pression et de la Temperature de la Veine Gazeuse en Vue de l’Evaluation des Performances des Turbines Aeronautiques et de leurs Composants
DTIC Science & Technology
1990-06-01
reduction software , prior to converting all remaining test which requires internal compensation. T he r sidual effect is pressures to engineering units...Reduction Conversion of Millivolts to Engineering Units. Carrying out numerical integrations to obtain area and mass weighted averages for various...Performance Assessment of Aircraft Turbine Engines and Components (Les MWthodes Recommande’es pour la Mesure de la Pression et de ]a Temperature de la
3. How mantle slabs drive plate tectonics.
PubMed
2002-10-04
The gravitational pull of subducted slabs is thought to drive the motions of Earth's tectonic plates, but the coupling between slabs and plates is not well established. If a slab is mechanically attached to a subducting plate, it can exert a direct pull on the plate. Alternatively, a detached slab may drive a plate by exciting flow in the mantle that exerts a shear traction on the base of the plate. From the geologic history of subduction, we estimated the relative importance of "pull" versus "suction" for the present-day plates. Observed plate motions are best predicted if slabs in the upper mantle are attached to plates and generate slab pull forces that account for about half of the total driving force on plates. Slabs in the lower mantle are supported by viscous mantle forces and drive plates through slab suction.
4. Improved Detection System Description and New Method for Accurate Calibration of Micro-Channel Plate Based Instruments and Its Use in the Fast Plasma Investigation on NASA's Magnetospheric MultiScale Mission
NASA Technical Reports Server (NTRS)
Gliese, U.; Avanov, L. A.; Barrie, A. C.; Kujawski, J. T.; Mariano, A. J.; Tucker, C. J.; Chornay, D. J.; Cao, N. T.; Gershman, D. J.; Dorelli, J. C.;
2015-01-01
The Fast Plasma Investigation (FPI) on NASAs Magnetospheric MultiScale (MMS) mission employs 16 Dual Electron Spectrometers (DESs) and 16 Dual Ion Spectrometers (DISs) with 4 of each type on each of 4 spacecraft to enable fast (30 ms for electrons; 150 ms for ions) and spatially differentiated measurements of the full 3D particle velocity distributions. This approach presents a new and challenging aspect to the calibration and operation of these instruments on ground and in flight. The response uniformity, the reliability of their calibration and the approach to handling any temporal evolution of these calibrated characteristics all assume enhanced importance in this application, where we attempt to understand the meaning of particle distributions within the ion and electron diffusion regions of magnetically reconnecting plasmas. Traditionally, the micro-channel plate (MCP) based detection systems for electrostatic particle spectrometers have been calibrated using the plateau curve technique. In this, a fixed detection threshold is set. The detection system count rate is then measured as a function of MCP voltage to determine the MCP voltage that ensures the count rate has reached a constant value independent of further variation in the MCP voltage. This is achieved when most of the MCP pulse height distribution (PHD) is located at higher values (larger pulses) than the detection system discrimination threshold. This method is adequate in single-channel detection systems and in multi-channel detection systems with very low crosstalk between channels. However, in dense multi-channel systems, it can be inadequate. Furthermore, it fails to fully describe the behavior of the detection system and individually characterize each of its fundamental parameters. To improve this situation, we have developed a detailed phenomenological description of the detection system, its behavior and its signal, crosstalk and noise sources. Based on this, we have devised a new detection
5. NASA Astrophysics Data System (ADS)
Ma, Xianglong; Zhang, Yinghong; Wen, Lichao; He, Yehu
2017-12-01
Aiming at the thickness detection of the plate surface attachment, a nondestructive testing method based on the Lamb wave is presented. This method utilizes Lamb wave propagation characteristics of signals in a bi-layer medium to measure the surface attachment plate thickness. Propagation of Lamb wave in bi-layer elastic is modeled and analyzed. The two-dimensional simulation model of electromagnetic ultrasonic plate - scale is established. The simulation is conducted by software COMSOL for simulation analysis under different boiler scale thickness wave form curve. Through this study, the thickness of the attached material can be judged by analyzing the characteristics of the received signal when the thickness of the surface of the plate is measured.
6. Visual illusions and plate design: The effects of plate rim widths and rim coloring on perceived food portion size
PubMed Central
McClain, Arianna; van den Bos, Wouter; Matheson, Donna; Desai, Manisha; McClure, Samuel M.; Robinson, Thomas N.
2013-01-01
OBJECTIVE The Delboeuf Illusion affects perceptions of the relative sizes of concentric shapes. This study was designed to extend research on the application of the Delboeuf illusion to food on a plate by testing whether a plate’s rim width and coloring influence perceptual bias to affect perceived food portion size. DESIGN AND METHODS Within-subjects experimental design. Experiment 1 tested the effect of rim width on perceived food portion size. Experiment 2 tested the effect of rim coloring on perceived food portion size. In both experiments, participants observed a series of photographic images of paired, side-by-side plates varying in designs and amounts of food. From each pair, participants were asked to select the plate that contained more food. Multi-level logistic regression examined the effects of rim width and coloring on perceived food portion size. RESULTS Experiment 1: Participants overestimated the diameter of food portions by 5% and the visual area of food portions by 10% on plates with wider rims compared to plates with very thin rims (P<0.0001). The effect of rim width was greater with larger food portion sizes. Experiment 2: Participants overestimated the diameter of food portions by 1.5% and the visual area of food portions by 3% on plates with rim coloring compared to plates with no coloring (P=0.01). The effect of rim coloring was greater with smaller food portion sizes. CONCLUSION The Delboeuf illusion applies to food on a plate. Participants overestimated food portion size on plates with wider and colored rims. These findings may help design plates to influence perceptions of food portion sizes. PMID:24005858
7. Geometry of the Cocos Plate Under North American Plate
Perez-Campos, X.
2015-12-01
The Cocos plate subducts under the North American plate with a complex geometry, and previous seismicity studies revealed some of this complexity. However, details of the geometry and the depth that the plate penetrates werelargely unknown. Since 2004, temporary experiments and the expansion of the permanent network of the Servicio Sismológico Nacional (SSN, Mexican National Seismological Service) have improved resolution of the plate geometry and have helped to map its descent into the upper mantle. Going from northwest to southeast, the Cocos plate appears to be fragmenting into north and south segments. The north segment subducts with an angle of ~30º and the south with an angle of ~10-15º. The transition is smooth near the trench and progresses to a tear at depth; this coincides with the projection of the Orozco Fracture Zone to depth. Also, this transition marks the limit of the presence to the south of an ultra slow velocity layer (USL) on top of the slab.South of this transition, the Cocos plate subducts horizontally , underplating the North American plate for a distance of ~140 to ~300 km from the trench. Along this horizontal region, silent slow events (SSE) and tectonic tremor (TT) have been observed. At a distance of 300 km from the trench (beneath central Mexico), the plate dives into the mantle with an angle of 76º to a depth of 500 km. This geometry changes abruptly to the south, marking the eastern limit of the USL. This change seems to be also characterized by a tear on the slab. Finally to the south, the Cocos plate subducts with a constant angle of 26º. This presentation summarizes the work of many contributors including A. Arciniega-Ceballos, M. Brudzinski, E. Cabral-Cano, T. Chen, R. Clayton,F. Cordoba-Montiel,P. Davis,S. Dougherty,F. Green, M. Gurnis, D. V. Helmberger, A. Husker,A. Iglesias, Y. Kim, V. Manea, D. Melgar, M. Rodríguez-Domínguez,S. K. Singh, T.-R. A. Song, C. M. Valdés-González, D. Valencia-Cabrera
8. The surface and through crack problems in layered orthotropic plates
NASA Technical Reports Server (NTRS)
Erdogan, Fazil; Wu, Binghua
1991-01-01
An analytical method is developed for a relatively accurate calculation of Stress Intensity Factors in a laminated orthotropic plate containing a through or part-through crack. The laminated plate is assumed to be under bending or membrane loading and the mode 1 problem is considered. First three transverse shear deformation plate theories (Mindlin's displacement based first-order theory, Reissner's stress-based first-order theory, and a simple-higher order theory due to Reddy) are reviewed and examined for homogeneous, laminated and heterogeneous orthotropic plates. Based on a general linear laminated plate theory, a method by which the stress intensity factors can be obtained in orthotropic laminated and heterogeneous plates with a through crack is developed. Examples are given for both symmetrically and unsymmetrically laminated plates and the effects of various material properties on the stress intensity factors are studied. In order to implement the line-spring model which is used later to study the surface crack problem, the corresponding plane elasticity problem of a two-bonded orthotropic plated containing a crack perpendicular to the interface is also considered. Three different crack profiles: an internal crack, an edge crack, and a crack terminating at the interface are considered. The effect of the different material combinations, geometries, and material orthotropy on the stress intensity factors and on the power of stress singularity for a crack terminating at the interface is fully examined. The Line Spring model of Rice and Levy is used for the part-through crack problem. The surface crack is assumed to lie in one of the two-layered laminated orthotropic plates due to the limitation of the available plane strain results. All problems considered are of the mixed boundary value type and are reduced to Cauchy type of singular integral equations which are then solved numerically.
9. Plate mode velocities in graphite/epoxy plates
NASA Technical Reports Server (NTRS)
Prosser, W. H.; Gorman, M. R.
1994-01-01
Measurements of the velocities of the extensional and flexural plate modes were made along three directions of propagation in four graphite/epoxy composite plates. The acoustic signals were generated by simulated acoustic emission events (pencil lead breaks or Hsu-Neilson sources) and detected by by broadband ultrasonic transducers. The first arrival of the extensional plate mode, which is nondispersive at low frequencies, was measured at a number of different distances from the source along the propagation direction of interest. The velocity was determined by plotting the distance versus arrival time and computing its slope. Because of the large dispersion of the flexural mode, a Fourier phase velocity technique was used to characterize this mode. The velocity was measured up to a frequency of 160 kHz. Theoretical predictions of the velocities of these modes were also made and compared with experimental observations. Classical plate theory yields good agreement with the measured extensional velocities. For predictions of the dispersion of the flexural mode, Mindlin plates theory, which includes the effects of shear deformation and rotatory inertia was shown to give better agreement with the experimental measurements.
10. A biomechanical comparison of conventional dynamic compression plates and string-of-pearls™ locking plates using cantilever bending in a canine Ilial fracture model.
PubMed
Kenzig, Allison R; Butler, James R; Priddy, Lauren B; Lacy, Kristen R; Elder, Steven H
2017-07-13
Fracture of the ilium is common orthopedic injury that often requires surgical stabilization in canine patients. Of the various methods of surgical stabilization available, application of a lateral bone plate to the ilium is the most common method of fixation. Many plating options are available, each having its own advantages and disadvantages. The purpose of this study was to evaluate the biomechanical properties of a 3.5 mm String-of-Pearls™ plate and a 3.5 mm dynamic compression plate in a cadaveric canine ilial fracture model. Hemipelves were tested in cantilever bending to failure and construct stiffness, yield load, displacement at yield, ultimate load, and mode of failure were compared. The mean stiffness of dynamic compression plate (116 ± 47 N/mm) and String-of-Pearls™ plate (107 ± 18 N/mm) constructs, mean yield load of dynamic compression plate (793 ± 333 N) and String-of-Pearls™ plate (860 ± 207 N) constructs, mean displacement at yield of dynamic compression plate (8.6 ± 3.0 mm) and String-of-Pearls™ plate (10.2 ± 2.8 mm) constructs, and ultimate load at failure of dynamic compression plate (936 ± 320 N) and String-of-Pearls™ plate (939 ± 191 N) constructs were not significantly different. No differences were found between constructs with respect to mode of failure. No significant biomechanical differences were found between String-of-Pearls™ plate and dynamic compression plate constructs in this simplified cadaveric canine ilial fracture model.
11. Lamb wave scattering by a surface-breaking crack in a plate
NASA Technical Reports Server (NTRS)
Datta, S. K.; Al-Nassar, Y.; Shah, A. H.
1991-01-01
An NDE method based on finite-element representation and modal expansion has been developed for solving the scattering of Lamb waves in an elastic plate waveguide. This method is very powerful for handling discontinuities of arbitrary shape, weldments of different orientations, canted cracks, etc. The advantage of the method is that it can be used to study the scattering of Lamb waves in anisotropic elastic plates and in multilayered plates as well.
12. Improving Plating by Use of Intense Acoustic Beams
NASA Technical Reports Server (NTRS)
Oeftering, Richard C.; Denofrio, Charles
2003-01-01
An improved method of selective plating of metals and possibly other materials involves the use of directed high-intensity acoustic beams. The beams, typically in the ultrasonic frequency range, can be generated by fixed-focus transducers (see figure) or by phased arrays of transducers excited, variously, by continuous waves, tone bursts, or single pulses. The nonlinear effects produced by these beams are used to alter plating processes in ways that are advantageous.
13. On 3D flow-structures behind an inclined plate
Uruba, Václav; Pavlík, David; Procházka, Pavel; Skála, Vladislav; Kopecký, Václav
Stereo PIV measurements has been performed behind the inclined plate, angle of attack 5 and 10 deg. Occurrence and dynamics of streamwise structures behind the plate trailing edge have been studied in details using POD method. The streamwise structures are represented by vortices and low- and highvelocity regions, probably streaks. The obtained results support the hypothesis of an airfoil-flow force interaction by Hoffman and Johnson [1,2].
14. Elaboration de nouvelles approches micromecaniques pour l'optimisation des performances mecaniques des materiaux heterogenes
Les modeles micromecaniques de transition d'echelles qui permettent de determiner les proprietes effectives des materiaux heterogenes a partir de la microstructure sont consideres dans ce travail. L'objectif est la prise en compte de la presence d'une interphase entre la matrice et le renforcement dans les modeles micromecaniques classiques, de meme que la reconsideration des approximations de base de ces modeles, afin de traiter les materiaux multiphasiques. Un nouveau modele micromecanique est alors propose pour tenir compte de la presence d'une interphase elastique mince lors de la determination des proprietes effectives. Ce modele a ete construit grace a l'apport de l'equation integrale, des operateurs interfaciaux de Hill et de la methode de Mori-Tanaka. Les expressions obtenues pour les modules globaux et les champs dans l'enrobage sont de nature analytique. L'approximation de base de ce modele est amelioree par la suite dans un nouveau modele qui s'interesse aux inclusions enrobees avec un enrobage mince ou epais. La resolution utilisee s'appuie sur une double homogeneisation realisee au niveau de l'inclusion enrobee et du materiau. Cette nouvelle demarche, permettra d'apprehender completement les implications des approximations de la modelisation. Les resultats obtenus sont exploites par la suite dans la solution de l'assemblage de Hashin. Ainsi, plusieurs modeles micromecaniques classiques d'origines differentes se voient unifier et rattacher, dans ce travail, a la representation geometrique de Hashin. En plus de pouvoir apprecier completement la pertinence de l'approximation de chaque modele dans cette vision unique, l'extension correcte de ces modeles aux materiaux multiphasiques est rendue possible. Plusieurs modeles analytiques et explicites sont alors proposee suivant des solutions de differents ordres de l'assemblage de Hashin. L'un des modeles explicite apparait comme une correction directe du modele de Mori-Tanaka, dans les cas ou celui ci echoue a
15. Elastomeric impression materials: a comparison of accuracy of multiple pours.
PubMed
Kumar, Dheeraj; Madihalli, Anand U; Reddy, K Rajeev Kumar; Rastogi, Namrataa; Pradeep, N T
2011-07-01
The aim of the present study is to compare the various elastomeric impression materials in terms of accuracy and dimensional stability, with respect to obtaining multiple casts from a single elastomeric impression at various times of pours. Three master dies were prepared for the impression making, two of these were made of brass containing a central hole with undercuts. The third die simulated a conventionally prepared typodont maxillary central incisor. Three elastomeric impression materials were chosen for the study. Each impression was poured at various time periods. Casts thus obtained were evaluated under a traveling microscope to evaluate various dimensional changes. Addition silicones provided dies which were shorter in height and bigger in diameter. Polyethers provided dies which were shorter in both height and diameter. Condensation silicones showed insignificant changes from the master die at the immediate pour but deteriorated rapidly after that in subsequent pours. None of the impression material showed a consistent behavior up to the fourth pour. They occasionally showed deviation from the pattern, but all these values were statistically insignificant. Polyethers showed lesser ability than both the addition silicones as well as the condensation silicones to recover from induced deformation. Addition silicones as well as the condensation silicones have better ability to recover from induced deformation when compared to polyether.
16. Electroless plated maghemite for three-dimensional magneto photonic crystals
Mito, Shinichiro; Kawashima, Takuya; Kawaguchi, Takuma; Sasano, Junji; Takagi, Hiroyuki; Inoue, Mitsuteru
2017-05-01
Three-dimensional magneto photonic crystals (3D-MPCs) are promising material for manipulating light in 3D space. In this study, we fabricated 3D-MPC that is filling the air-gap of opal photonic crystal with magnetic material by electroless plating. The electroless plating is an attractive film-forming method which provides magnetic material films on various substrates in aqueous solution at 24-90 °C. As magnetic material for filling the air-gap, maghemite (γ-Fe2O3) film was plated in opal photonic crystal. The plated maghemite film showed a Faraday rotation of 0.6 deg./μm at 440 nm and significantly lower absorption than magnetite. The plated opal showed photonic band gap and magneto-optic response. Faraday rotation of the plated opal was enhanced at the band edge. The photonic band gap and the Faraday rotation spectra were changed as a function of incident angle of light. Electroless plating of maghemite could be promising technique for fabricating 3D-MPCs.
17. Mass production of the large-sized nuclear plate for J-PARC E07
Ito, Hiroki; Nakazama, Kazuma; Hoshino, Kaoru; Yoshida, Jyunya; Tint, Khin Than; Soe, Mint Kyaw; Kinbara, Shinji; Mishina, Akihiro; Endo, Yoko; Kobayashi, Hidetaka; J-PARC E07 Collaboration
2014-09-01
In J-PARC E07, about 102 double lambda hypernuclei will be detected, which is 10 times or more than that of the KEK PS-E373 experiment. Therefore, it is necessary for large-scale emulsion plates to avoid time-consuming job for exchange emulsion stack in beam exposure. We also use huge amount of emulsion gel with weight of 2.1 t, which is about 3 times' quantity used for E373. Nuclear emulsion plate is made of photographic emulsion gel as a dry film. Melted gel in 40°C is poured on a thin polystyrene film in the size of 710 × 700 mm2. These sheets were dried slowly for two days in drying cabinet under 28°C and RH. 75%. After drying, the surface was coated by thin gelatin layer with 0.3 μm thickness. Regarding the 2nd face, it was poured and coated in the same manner. Finally we dry it well under 25°C and RH. 60% and cut into four 350 × 345 mm2 plates. We evaluated the performance about these plates. The length of upper, lower, right-hand and left-hand side are 345.08 +/- 0.05 mm, 345.23 +/- 0.13 mm, 350.03 +/- 0.04 mm, and 350.80 +/- 0.05 mm, respectively. The density is 3.676 +/- 0.032 g/cm3, enough quality for the experiment.
18. Plate tectonics of the Mediterranean region.
PubMed
McKenzie, D P
1970-04-18
The seismicity and fault plane solutions in the Mediterranean area show that two small rapidly moving plates exist in the Eastern Mediterranean, and such plates may be a common feature of contracting ocean basins. The results show that the concepts of plate tectonics apply to instantaneous motions across continental plate boundaries.
19. The vibroacoustic response and sound absorption performance of multilayer, microperforated rib-stiffened plates
Zhou, Haian; Wang, Xiaoming; Wu, Huayong; Meng, Jianbing
2017-10-01
The vibroacoustic response and sound absorption performance of a structure composed of multilayer plates and one rigid back wall are theoretically analyzed. In this structure, all plates are two-dimensional, microperforated, and periodically rib-stiffened. To investigate such a structural system, semianalytical models of one-layer and multilayer plate structures considering the vibration effects are first developed. Then approaches of the space harmonic method and Fourier transforms are applied to a one-layer plate, and finally the cascade connection method is utilized for a multilayer plate structure. Based on fundamental acoustic formulas, the vibroacoustic responses of microperforated stiffened plates are expressed as functions of a series of harmonic amplitudes of plate displacement, which are then solved by employing the numerical truncation method. Applying the inverse Fourier transform, wave propagation, and linear addition properties, the equations of the sound pressures and absorption coefficients for the one-layer and multilayer stiffened plates in physical space are finally derived. Using numerical examples, the effects of the most important physical parameters—for example, the perforation ratio of the plate, sound incident angles, and periodical rib spacing—on sound absorption performance are examined. Numerical results indicate that the sound absorption performance of the studied structure is effectively enhanced by the flexural vibration of the plate in water. Finally, the proposed approaches are validated by comparing the results of stiffened plates of the present work with solutions from previous studies.
20. Beyond plate tectonics - Looking at plate deformation with space geodesy
NASA Technical Reports Server (NTRS)
Jordan, Thomas H.; Minster, J. Bernard
1988-01-01
The requirements that must be met by space-geodetic systems in order to constrain the horizontal secular motions associated with the geological deformation of the earth's surface are explored. It is suggested that in order to improve existing plate-motion models, the tangential components of relative velocities on interplate baselines must be resolved to an accuracy of less than 3 mm/yr. Results indicate that measuring the velocities between crustal blocks to + or - 5 mm/yr on 100-km to 1000-km scales can produce geologically significant constraints on the integrated deformation rates across continental plate-boundary zones such as the western United States. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5435928106307983, "perplexity": 4721.4751993762375}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618038084765.46/warc/CC-MAIN-20210415095505-20210415125505-00219.warc.gz"} |
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# High Precision Particle Swarm Optimization Algorithm (HiPPSO)
## Abstract
Particle Swarm Optimization (PSO) is a nature-inspired meta-heuristic adaptable to continuous optimization problems. To avoid numerical instabilities or artifacts it is necessary to evaluate floating point calculations with high precision. Our High Precision Particle Swarm Optimization (HiPPSO) software realizes this demand. Additionally our software provides an automatic procedure to adjust precision if it is necessary for accurate evaluations. This enables a fast execution time because the software always evaluates the calculations with suitable precision and does not use too much precision if it is not necessary. HiPPSO is implemented in C++ and has a very flexible class hierarchy to replace subroutines on purpose or extend functionality by simply implementing abstract classes. The software is available on a GitHub repository at https://github.com/alexander-rass/HiPPSO.
Keywords:
How to Cite: Raß, A., 2020. High Precision Particle Swarm Optimization Algorithm (HiPPSO). Journal of Open Research Software, 8(1), p.4. DOI: http://doi.org/10.5334/jors.282
Published on 09 Mar 2020
Accepted on 18 Feb 2020 Submitted on 12 Jun 2019
## (1) Overview
### Introduction
In real world situations we are often facing hard optimization problems. A successful research field covering these problems is the application of meta-heuristics, which are highly flexible and can optimize functions without deep knowledge of the objective function (Black Box optimization). Particle Swarm Optimization (PSO) introduced by Kennedy and Eberhart [1, 2] is a nature-inspired meta-heuristic covering optimization problems with a continuous domain, e.g., the ℝD or a constrained subset of ℝD. The algorithm manages a collection of particles, the swarm. Each particle p has its position xp, representing an admissible solution, and its velocity υp. Additionally each particle p knows its local attractor lp, the best position visited so far by p, and the swarm additionally knows the global attractor g, the best position visited so far by any particle. The classical movement is defined by the following two movement equations evaluated for each dimension d, each particle p and every iteration.
$\begin{array}{l}{\upsilon }_{p,d,\mathit{\text{new}}}=\chi \cdot {\upsilon }_{p,d,\mathrm{old}}+{c}_{l}\cdot {r}_{l}\cdot \left({l}_{p,d}-{x}_{p,d,\mathit{\text{old}}}\right)\\ \text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}+{c}_{g}\cdot {r}_{g}\cdot \left({g}_{d}-{x}_{p,d,\mathrm{old}}\right)\\ {x}_{p,d,\mathit{\text{new}}}={x}_{p,d,\mathrm{old}}+{\upsilon }_{p,d,\mathit{\text{new}}}.\end{array}$
In this movement equations χ, cl and cg are swarm parameters controlling the ability of exploitation, i.e., the swarm is looking for better solutions close to the attractor, and exploration of new territory in the search domain. Furthermore rl and rg are random values which are newly sampled on each evaluation and are uniformly distributed in the interval [0,1] supplying random perturbation. After the position update the attractors are updated if the current position is better. This update can be performed immediately or delayed at the end of the iteration depending on the selected configuration in the configuration file.
The HiPPSO was implemented to establish a highly flexible PSO library, which enables the researcher to analyze the behavior of the PSO with a new level of quality investing only a small effort. The implementation of HiPPSO already supplies a wide variety of features and extensions known for standard PSO algorithms and, furthermore, some introductory examples are supplied. Therefore even for people who are no researchers it would be very interesting to use HiPPSO, e.g., they can use it for optimizing their own functions. For a more detailed overview on how the HiPPSO can be used see the Section “Reuse potential”.
There are already results on convergence analysis for the PSO, but mostly they are either performed on slightly modified versions of the classical PSO or on very reduced problem instances. For an exemplary discussion on a modified version of the classical PSO see [3] which uses some random perturbation only in situations of premature/degenerate convergence – this version can (among other versions) be selected as an update strategy for HiPPSO. [3] is also a reference for reduced problem instances as the authors show convergence of the particles of PSO to local optima for single dimensional problems. Other findings are restricted on measurements on average quality of the result after reaching a budget limit of function evaluations [5]. All this is possible with standard PSO implementations and also with HiPPSO. Our supplied implementation of High Precision Particle Swarm Optimization (HiPPSO) additionally enables researchers to measure completely novel characteristics of the PSO algorithm. With limited precision only a limited part of the process can be used until precision errors completely compromise the behavior. With arbitrary high precision or self-adjusting precision, which are both available in HiPPSO, researchers can observe much longer periods of convergence and therefore have much better and reliable data, which allows the researcher to quantify the speed of convergence and then also to determine the delay of convergence because in the beginning the behavior is most likely a bit different.
To get a detailed impression on the differences between calculations with limited/fixed precision and self-adjusting precision we present examples of the PSO algorithm optimizing the well-known benchmark function Rosenbrock, which is defined as $f\left(x\right)={\sum }_{i=0}^{D-2}\left(100\cdot {\left({x}_{i+1}-{x}_{i}^{2}\right)}^{2}+\left(1-{x}_{i}^{2}\right)\right)$. We use the Rosenbrock function on a search space with D = 4 dimensions. For optimization with the PSO we use the parameters χ = 0.72984 and cl = cg = 1.496172 which are well-established in the literature. The position of the particles will be initialized uniformly at random in the search space [–30, 30]D and the initial velocities are set to zero. No bound handling strategy is used but the function evaluates to +∞ outside the search space bounds.
In Figure 1 the function value of the Rosenbrock function evaluated on the global attractor (the best position found so far) is displayed while optimizing with four particles with either self-adjusting precision or with fixed precision (64 bits for mantissa). In this figure one can see the most obvious drawback of fixed precision: The result is only correct up to a fixed precision. In contrast, with self-adjusting precision the result gets the more precise the longer the optimization is executed.
Figure 1
Development of the global attractor value of the PSO algorithm with constant/fixed precision (64 bits for mantissa) and adjusting precision while optimizing the four dimensional Rosenbrock function with four particles.
In Figure 2 the same data is displayed while PSO is optimizing only with two particles. Here the evaluation with fixed precision and the evaluation with self-adjusting precision (using the same random values for initialization and update) produce almost equal results according to the best found solution. For the case with fixed precision we can not distinguish the situation appearing in Figure 1 from the situation appearing in Figure 2. Consequently, we do not know whether we have a bad result or are close to some local or global optimum up to precision issues. The problem gets even worse if we look at further statistics obtained from the evaluations with two particles. In [4] a potential has been introduced to analyze bad convergence.
Figure 2
Development of the global attractor value of the PSO algorithm with constant/fixed precision (64 bits for mantissa) and adjusting precision while optimizing the four dimensional Rosenbrock function with two particles.
Definition 1Let f be the objective function then we call
$\psi \left(d\right):=\underset{0\le p
potential, where x̃p,d: = xp + edυp, ed is the d th Cartesian unit vector andis element-wise multiplication and we call Ψ(d): = ψ(d)/max0≤i<D ψ(i) relative potential.
The relative potential captures the importance of each dimension and in [4] it has been argued that if this relative potential is quite low for some dimensions then the PSO does not optimize them.
In Figure 3 the relative potential Ψ is presented. To be more precise in Figure 3a the development of the relative potential with fixed precision is displayed. The relative potential of the first dimension vanishes quite early as Ψ becomes exactly zero. The same happens for the second dimension after approximately 2 000 iterations and for the remaining dimensions after approximately 15 000 iterations. No actual tendency is noticeable until results get completely useless when differences are so small that they become zero. Also the data before is not necessarily trustworthy as precision issues could have compromised them.
Figure 3
Development of the relative potential Ψ of the PSO algorithm with constant/fixed precision (64 bits for mantissa) and adjusting precision while optimizing the four dimensional Rosenbrock function with two particles.
With self-adjusting precision we can observe the relative potential for more iterations as visualized in Figure 3b. The last two dimensions stay quite close to 1 = 100, which signals high importance, and the first two dimensions are continuously decreasing to zero, which signals low importance. Therefore it is obvious that the PSO actually optimizes only the last two dimensions. In [4] it has been argued that the relative potential in dimensions which are not optimized any longer decreases (on average) linearly in logarithmic scale. If only fixed precision is used, this insight would not be possible at all.
All the data has been produced by HiPPSO as it is possible to use fixed as well as self-adjusting precision for evaluation. The authors of [4] also used an early version of this implementation for their experiments.
### Implementation and architecture
The architecture is built to supply a highly flexible basis with easily exchangeable parts. Before starting the HiPPSO program, one has to generate a configuration file specifying all parameters, the objective function, the update strategies, bound handling strategies, evaluated statistics and much more. To simplify the usage some example configuration files are supplied. Also an online tool for configuration file generation can be used to describe the intended configuration. A link to that tool can be found in the main homepage for the HiPPSO on GitHub. The whole PSO algorithm is also extremely modularized, which enables researchers to just exchange a single module in their implementation and still use all remaining parts from the HiPPSO framework. In most cases writing source code is not necessary as most standard variants are already implemented and can be picked by the configuration file.
The main structure of the HiPPSO supplies all active modules (classes) and configured properties for the PSO by static variables within the configuration namespace (contained in the base namespace highprecisionpso). The most important statically available elements in the namespace configuration are
• + g_function: Function*
• the pointer to the objective function
• + g_statistics: Statistics*
• the pointer to the current statistics – the statistics include pointers to particles
• + g_dimensions: int
• the number of dimensions of the search space
• + g_particles: int
• the number of particles
• + g_chi: double
• the parameter χ of the movement equation for the PSO
• + g_coefficient_local_attractor: double
• the parameter cl of the movement equation for the PSO
• + g_coefficient_global_attractor: double
• the parameter cg of the movement equation for the PSO
• + g_position_and_velocity_updater: PositionAndVelocityUpdater*
• the pointer to the position and velocity update procedure
• + g_bound_handling: BoundHandling*
• the pointer to the bound handling procedure
• the pointer to the velocity adjustment strategy
• + g_neighborhood: Neighborhood*
• the pointer to the neighborhood topology.
As visualized in Figures 4 and 5 the active statistics class, which is accessible by configuration::g_statistics, stores (among other data) pointers to all particles and the current iteration counter and the particles store an index, the position, the velocity and the position of the local attractor. For position, velocity and the position of the local attractor also get and set functions are available. Therefore all essential data can be accessed and manipulated through variables in the configuration namespace.
Figure 4
Class diagram of Statistics class.
Figure 5
Class diagram of Particle class.
The main PSO loop is executed in the DoPso function implemented in the file main.cpp. There for each iteration (outer for loop) and for each particle (inner for loop) the position update is executed. If the default position and update procedure is picked then the standard movement equations which are described in the introduction will be applied.
In the following we describe the intended workflow for updating the particles which clarifies the intended interaction between the selected modules.
The update procedure can be separated into three subroutines. For each particle p of type Particle, which should be updated, the subroutine Update of the chosen position and velocity updater configuration::g_position_and_velocity_updater of type PositionAndVelocityUpdater is called by the UpdatePosition function of particle p. It is intended that this subroutine calculates the new velocity, e.g., by the standard movement equations and then delegates the remaining update to the bound handling strategy. Therefore the intended sequence of instructions is
• to calculate the new velocity and to call SetVelocity of particle p with the new velocity and
• to call SetParticleUpdate of chosen bound handling strategy configuration::g_bound_handling of type BoundHandling.
It is intended that the subroutine SetParticleUpdate mainly calculates the new position of the particle. The expected sequence of instructions is
• to calculate the new position,
• to call SetPosition of particle p with the new position and
The subroutine AdjustVelocity mainly adjusts the velocity according to the position update. It can be possible that two or all three parts have to be combined to achieve the needed behavior. This is also possible. The update of the local attractor is performed automatically by the particle class when SetPosition is called. The global attractor is updated either directly after updating the local attractor or may be applied at the end of a complete iteration (depending on the chosen variant by the configuration file).
The chosen neighborhood configuration::g_neighborhood of type Neighborhood supplies the ability to query the global attractor, which might be the best of all positions or just the best positions of some neighboring particles. The function GetGlobalAttractorPosition will usually be called by the position and velocity updater.
The bound handling strategy might also change the distance to some position because the search space may wrap around. Therefore we also supplied the function GetDirectionVector to evaluate the difference between two positions.
All specified statistics will update after all positions and attractors are updated. During calculation of statistics the evaluation has access to all data including but not limited to particle position and velocity and current state of classes guiding the update process.
### Quality control
The test suite of this implementation can be executed by make test in the base folder of the project. All tests are also checked by the continuous integration service provided by Travis CI. Additionally the test coverage is checked by the service of Coveralls which confirm a test coverage of at least 90%. The reason for not being closer to 100% is only that checks that should not happen (such lines can not be covered at all) or checks whether the supplied configuration files supply correct configuration instructions are not covered by supplied tests as this would mean to call the program with invalid configurations. Executing the program with invalid configuration files would cause exceptions and additionally some information on the incorrect configuration options would be displayed.
The tests cover verification of functionality as well as the guarantee to generate reproducible results. This is achieved by three types of tests.
• We are comparing results of evaluations with the double data type with evaluations of the used mpf_t data type, which is necessary for high precise calculations. The results of evaluations with the double data type are up to the precision of the double data type correct for functions of the standard C++ library and also other reference implementations are much less error prone. We check here that evaluations with high precision produce the same results as evaluations with double data type up the precision of the double data type.
• – We especially checked trigonometric functions (sin, cos, tan, …),
• – exponential functions (exp, log, ln, pow, …)
• – and all implemented benchmark functions (Sphere, Schwefel, Rosenbrock, Rastrigin, …).
• We are checking that the precision of evaluated functions is closely related to the currently active precision. For this purpose we evaluate functions with different precisions and check that the result produced with lower precision is equal to the result with higher precision if it is truncated to the lower precision.
• Finally we are checking that the current executable produces absolutely identical results compared to a reference evaluation of this software. Here any available module or configuration option (objective function, bound handling strategy, neighborhood topology, …) is tested at least once.
These criteria enable researchers to use this software for scientific works as it is guaranteed that anyone can use this software to independently confirm results of others if the configuration of the software is published.
## (2) Availability
### Operating system
HiPPSO has been tested successfully on Ubuntu 16.04 (also by Travis CI), Ubuntu 18.04 and Windows 10. Additionally HiPPSO is successfully tested by Travis CI on OS-X but functionality is not guaranteed.
### Programming language
C++ with gcc version ≥ 5.5.
### Additional system requirements
There are no additional system requirements exceeding the limits of a basic desktop PC.
### Dependencies
When running HiPPSO from source code, the GNU Multiple Precision Arithmetic Library (GMP library) version ≥ 6 is needed.
On Windows operating system we suggest using Cygwin with components
• gcc,
• m4 and
• make.
The GMP library has to be installed additionally from the homepage of the project (https://gmplib.org/).
On Ubuntu one can simply install all components by sudo apt-get install of the components
• g++,
• make and
• libgmp-dev (GMP library).
After preparation one can install HiPPSO by the command make in the base folder of the project with Cygwin on Windows or with Terminal on Ubuntu.
### List of contributors
Authored and maintained by Alexander Raß with minor contributions from Manuel Schmitt.
### Software location
#### Archive
Name: HiPPSO
Persistent identifier: DOI: 10.5281/zenodo.3518175
Licence: MIT License (MIT)
Publisher: Alexander Raß
Version published: 1.0.2
Date published: 24/10/19
#### Code repository GitHub
Name: HiPPSO
Persistent identifier:https://github.com/alexander-rass/HiPPSO
Licence: MIT License (MIT)
Date published: 24/10/19
English
## (3) Reuse potential
This Software can be reused by scientists in multiple ways. It can be used for optimization/minimization of an objective function specified by the user without knowledge of the PSO algorithm itself, for quality measurements of the PSO algorithm to extend the understanding of the mechanisms of the PSO and for integration and testing of new modules of the PSO.
Other researchers looking for a tool to optimize/minimize some function in the continuous domain can use this tool for optimization. It is only necessary to describe the function and the software can immediately start to optimize and present optimized solutions to the user. A wide range of objective functions are already implemented (Sphere, Rosenbrock, Rastrigin, …). Maybe the objective of the researcher is very specific and somehow new (and not present in any benchmark set) but it still can be specified to the software as it is possible to specify objective functions by some grammar which is described inside the guideline configuration files. Alternatively an online tool for configuration file generation can be used to describe the intended objective function. A link to that tool can be found in the main homepage for the HiPPSO on GitHub. Even complicated functions like Ackley can be described by that grammar and can be minimized without programming a single line of code. If it is still not possible to specify the needed objective function it is possible to write a piece of source code implementing the needed objective function and integrate it to HiPPSO by implementing the abstract class Function. Usually this should not be necessary but in case it is a link to some guidelines how your function can be implemented and activated can be found on the main GitHub page of HiPPSO in the section “Extensibility”.
Also any quality measurement which is needed for analysis of the PSO algorithm can be produced by this software. The statistics which should be extracted by the PSO can be specified similarly to the objective function by a grammar (see also the online tool for configuration file generation). Examples of predefined options are positions, velocities, attractor positions, function values of those and many functions dependent on those characteristics. It can also be specified at which iterations the statistics should be produced. All evaluations can be made with arbitrary, self-adjusting precision and are therefore highly reliable and can be displayed for very large number of iterations.
A future work using HiPPSO is measuring precisely what the speed of convergence is, i.e., it answers the question how long it takes to improve the result of an objective function by some specified value of additional digits.
Last but not least researchers developing PSO modules can use this software. They can use the complete base structure of the PSO and just replace some part of the PSO algorithm by their version. Explicit options for replacement are for example bound handling strategies, neighborhood topologies, calculation of new position and many more. Links to some guidelines how your new modules can be implemented and activated can be found on the main GitHub page of HiPPSO in the section “Extensibility”.
If there appear any issues or complications while using HiPPSO one can use either GitHub issues or send a mail to Alexander Raß (Alexander.Rass@fau.de) to receive support.
## Competing Interests
The author has no competing interests to declare.
## References
1. Eberhart, R C and Kennedy, J 1995 A new optimizer using particle swarm theory. In: Proc. 6th International Symposium on Micro Machine and Human Science, 39–43. DOI: https://doi.org/10.1109/MHS.1995.494215
2. Kennedy, J and Eberhart, R C 1995 Particle swarm optimization. In: Proc. IEEE International Conference on Neural Networks, 4: 1942–1948. DOI: https://doi.org/10.1109/ICNN.1995.488968
3. Schmitt, M and Wanka, R 2015 Particle Swarm Optimization Almost Surely Finds Local Optima. In: Theoretical Computer Science, 561A: 57–72. DOI: https://doi.org/10.1016/j.tcs.2014.05.017
4. Raß, A, Schmitt, M and Wanka, R 2015 Explanation of Stagnation at Points that are not Local Optima in Particle Swarm Optimization by Potential Analysis. In: Proc. 17th Genetic and Evolutionary Computation Conference (GECCO), 1463–1464. DOI: https://doi.org/10.1145/2739482.2764654
5. Trelea, I 2003 The particle swarm optimization algorithm: Convergence analysis and parameter selection. In: Information Processing Letters, 317–325. DOI: https://doi.org/10.1016/S0020-0190(02)00447-7 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 3, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3760787546634674, "perplexity": 1342.8031841080744}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656103337962.22/warc/CC-MAIN-20220627164834-20220627194834-00163.warc.gz"} |
https://alphons.io/2412/what-is-the-formula-to-convert-radians-per-second-rad-slash-s-to-miles-per-hour-mph/ | 👋 Hello! I'm Alphonsio the robot. Ask me a question, I'll try to answer.
# What is the formula to convert radians per second [rad/s] to miles per hour [mph]?
The formula to convert radians per second [rad/s] to miles per hour [mph] is given by:
where:
• is the linear velocity expressed in miles per hour [mph]
• is the angular velocity expressed in radians per second [rad/s]
• is the radius expressed in meters [m]
More | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9909010529518127, "perplexity": 2378.196388740496}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780056548.77/warc/CC-MAIN-20210918154248-20210918184248-00419.warc.gz"} |
https://bryanwweber.github.io/thermostate/installation.html | # Installation¶
## Conda¶
The preferred installation method is to use conda. Using Conda, ThermoState can be installed for either Python 3.5, 3.6, or 3.7. If you have an existing Conda environment with one of those Python versions, installing ThermoState can be done by
conda install -c bryanwweber thermostate conda-forge::pint
This installs Pint from the conda-forge channel; if you would like to use another channel to install Pint, change the conda-forge to be the name of the channel you prefer. If Pint is already installed in your environment, the conda-forge::pint can be omitted entirely.
If you do not have an environment with Python 3.5, 3.6, or 3.7, you can create a new environment with
conda create -n thermostate -c bryanwweber thermostate conda-forge::pint
## Pip¶
Alternatively, ThermoState can be installed with pip.
pip install thermostate
## From Source¶
ThermoState is a pure-Python package that supports any Python version 3.5 and higher. To install from source, clone the source code repository and install using pip.
git clone https://github.com/bryanwweber/thermostate
cd thermostate
pip install . | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.16477251052856445, "perplexity": 7792.782087986257}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560627999130.98/warc/CC-MAIN-20190620024754-20190620050754-00226.warc.gz"} |
https://forum.allaboutcircuits.com/threads/project-arduino-temperature-reading-using-a-ds18b20-with-74hc595-4x-seven-segment-displays.133589/ | # Project: Arduino temperature reading using a DS18B20 with 74HC595 / 4x Seven Segment displays
#### Remembermyname
Joined Sep 6, 2015
91
Greetings,
Recently, I had been trying to build an Arduino temperature reader using a DS18B20 and display the output on 4x Seven Segment Displays. With a lot of trial and error (mostly errors), this was completed. This project was set up using an Arduino Nano driving a single multiplexed 74HC595 to drive the displays. It is capable of reading the full range of the DS18B20 (-55°C to +125°C (-67°F to +257°F)). The code is currently set up to read Fahrenheit degrees but can easily be changed to read Celsius. It has been tested on its low end with an inverted can of keyboard duster to -48.0F to its high end with boiling water to ~210.0F. I had no intention of displaying an F or a C in the display since I knew which temperature it was being used for otherwise, I'd have to add a 5th digit.
This was built using a breadboard. Granted, it would have looked better with less wiring using a single 4 digit display. The 4 individual digits were wired for the same purpose as this is what I had on hand.
Below is the schematic:
The schematic was made with gSchem which is part of the gEDA suite
Below is the zip file containing the schematic including the custom symbols that need to be installed for the schematic:
This can be used later if a PCB is to be designed out of it.
*****
The following parts for this build are required:
Parts list:
1x Arduino Nano
1x 75HC595 8bit shift register - 16 pin DIP IC
1x 4.7k ohm 1/4 watt resistor
1x DS18B20 Maxim/Dallas temperature IC (can come in TO-92 case or prebuilt into a sealed cable assembly)
8x 330 ohm 1/8 watt resistors
4x 5011 Common Anode 7 segment LED display*
* You can also use a 4 digit 7 segment display module to connect to the 74HC595. It will save you a LOT of tedious breadboard wiring.
*****
I wanted to build this as a basic starting platform for other projects such as a deep freezer controller with LED readout. The use of the single 74HC595 rendered the Arduino with free pins to work with control relays, etc. The readout is formatted to display numbers without leading zeros and to the tenth's decimal place. The code involved was taken from http://www.pial.net/arduino-controlling-a-4-digit-seven-segment-display/ and modified. The code uses the DallasTemperature and OneWire libraries. This code uses 5054 bytes (16% of program storage space).
Compiled with Arduino IDE 1.6.7
The OneWire.h and DallasTemperature.h library files are required and need to be installed to your Arduino IDE
https://www.pjrc.com/teensy/td_libs_OneWire.html
Which will lead you to the OneWire GitHub page to retreive the latest version of the library at:
https://github.com/PaulStoffregen/OneWire
The OneWire library version used in this build is 2.3.3 and is pasted below:
View attachment OneWire-master.zip
https://milesburton.com/Dallas_Temperature_Control_Library (Down at the time of this posting)
The needed Dallas temperature control library can be found here:
https://github.com/milesburton/Arduino-Temperature-Control-Library
The DallasTemperature control library version used in this build is 3.7.7 and is pasted below:
View attachment Arduino-Temperature-Control-Library-master.zip
The code is pasted below:
C:
/*
* Modified with additions to original code 3/22/2017- Lawrence Hallman
*
* This code was taken and modified from the original code which can be found at:
* http://www.pial.net/arduino-controlling-a-4-digit-seven-segment-display/
*
*/
#include <OneWire.h>
#include <DallasTemperature.h>
#define ONE_WIRE_BUS 2
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
const int ledPin = 13;// LED connected to digital pin 13
const int latchPin = 8;// Pin connected to ST_CP of 74HC595
const int clockPin = 9;// Pin connected to SH_CP of 74HC595
const int dataPin = 10;// Pin connected to DS of 74HC595
const int digitPins[4] = {
3,4,5,6}; //pins to control the 4 common anode pins of the display
const byte digit[12] = //seven segment digit bits + blank + minus
{
B00111111, //0
B00000110, //1
B01011011, //2
B01001111, //3
B01100110, //4
B01101101, //5
B01111101, //6
B00000111, //7
B01111111, //8
B01101111, //9
B00000000, //Blank
B01000000 //-
};
int digitBuffer[4] = {
1};
int digitScan = 0;
int soft_scaler = 0;
float tempC, tempF;
int tmp;
boolean sign = false;
void setup() {
TCCR2A = 0;
TCCR2B = (1<<CS21);
TIMSK2 = (1<<TOIE2);
TCNT2 = 0;
pinMode(ledPin, OUTPUT);
for(int i=0;i<4;i++)
{
pinMode(digitPins[i],OUTPUT);
}
pinMode(latchPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);
sensors.begin();
}
ISR(TIMER2_OVF_vect) {
soft_scaler++;
if(soft_scaler==15)
{
refreshDisplay();
soft_scaler = 0;
}
};
void refreshDisplay()
{
for(byte k=0;k<4;k++)
{
digitalWrite(digitPins[k], LOW);
}
digitalWrite(latchPin, LOW);
shiftOut(dataPin, clockPin, MSBFIRST, B11111111);
digitalWrite(latchPin, HIGH);
delayMicroseconds(50);
digitalWrite(digitPins[digitScan], HIGH);
digitalWrite(latchPin, LOW);
if(digitScan==1)
{
shiftOut(dataPin, clockPin, MSBFIRST, ~(digit[digitBuffer[digitScan]] | B10000000)); //inserting the dot
}
else
{
shiftOut(dataPin, clockPin, MSBFIRST, ~digit[digitBuffer[digitScan]]);
}
digitalWrite(latchPin, HIGH);
digitScan++;
if(digitScan>3) digitScan=0;
}
void loop()
{
digitalWrite(ledPin, HIGH);
sensors.requestTemperatures();
tempC = sensors.getTempC(insideThermometer);
tempF = DallasTemperature::toFahrenheit(tempC);
tmp = int(tempF*10);
if (tempF < 0){
sign = true;
tmp = abs(tmp);
}
else{
sign = false;
}
if (int(tmp)/1000 == 0){
digitBuffer[3] = 10;
if (sign){
digitBuffer[3] = 11;
}
}
else{
digitBuffer[3] = int(tmp)/1000;
}
if (int(tmp)/1000 == 0 && (int(tmp)%1000)/100 == 0) {
digitBuffer[2] = 10;
if (sign){
digitBuffer[2] = 11;
digitBuffer[3] = 10;
}
}
else{
digitBuffer[2] = (int(tmp)%1000)/100;
}
digitBuffer[1] = (int(tmp)%100)/10;
digitBuffer[0] = (int(tmp)%100)%10;
digitalWrite(ledPin, LOW);
delay(500);
}
The code along with the needed libraries is contained in the zip file below:
Many thanks to @ErnieM for your help in making this possible.
Last edited:
#### Remembermyname
Joined Sep 6, 2015
91
If you wish to build the circuit on a breadboard, the schematic is complete but I feel that it can appear confusing or overwhelming to some readers, especially in the 74HC595 to digits area. So, I've broken the schematic down into 12 assembly steps to hopefully help ease this process if you are using 4x single common anode displays. Please be aware that some common anode displays may differ in pinout designation. Please refer to your device's data sheet for the best information.
I've included the pinouts explanation for a generic 5011 Common Anode 7 segment LED display, the 74HC595 (16 pin DIP package) and the Arduino Nano for reference. These are pasted below:
The 5011 Common Anode 7 segment LED display
The 74HC595 Shift Register (16 pin DIP)
The Arduino Nano
#### Remembermyname
Joined Sep 6, 2015
91
Steps to building the diplay portion on the breadboard:
In my assembly, I used an 830 pin dual bus breadboard. I installed the digit modules first towards one end but I left three pins spacing from the end for the DS18B20.
You may notice that in the schematic, pins 3 and 8 (CA1 and CA2) are connected. I placed a jumper accross the breadboard gap for this under the display module. Most displays have the common anodes already connected internally so in most cases, this may not be necessary. I simply put it there just in case.
Picture the digits from left to right. Digit 4 will be placed towards the DS18B20 end of the breadboard. If you have a larger breadboard, you're in luck. The digits wiring was tight.
Step1
Connect the G segments of each digit.
Step 2
Connect the F segments of each digit.
Step 3
Connect the A segments of each digit.
Step 4
Connect the B segments of each digit.
The top half of the display assembly is finished. Now for the bottom half.
Step 5
Connect the E segments of each digit.
Step 6
Connect the D segments of each digit.
Step 7
Connect the C segments of each digit.
Step 8
Connect the Decimal Point segments of each digit.
The display assembly is complete. Each segment should be paralleled. Now, one resistor for each segment can be installed. The resistors together will take up 8 rows from the innermost digit. One end of each resistor connected to the paralleled segments, the other to the 74HC595
Last edited:
#### Remembermyname
Joined Sep 6, 2015
91
Step 9
Install the 74HC595. Each 330 ohm resistor represents a segment for each display as the output to all four digits is multiplexed.
Install the Arduino Nano on the other end of the breadboard and connect the power and ground to the 74HC595.
Step 10
Now, connect the Latch, Data, and Clock pins of the 74HC595 to the Arduino Nano.
Step 11
Now, connect the anodes of each display separately to the Arduino Nano.
Step 12
Install the DS18B20 and the 4.7k ohm resistor.
From step 1, 3 spaces are open on the digits end of the breadboard. You can actually place the DS18B20 anywhere on the board you see fit. I found convenient to place it on the digits end. Connect the Power, Ground and Data pins of the DS18B20. Install a 4.7k ohm resistor between the Power and Data pins. Then connect the data to the D2 pin on the Arduino Nano.
*Be certain to mind the pinouts of the DS18B20. It doesn't like being connected backwards to power and ground.*
Connect the Arduino Nano to a USB and your Arduino IDE, send in the sketch to the Arduino.
All images, schematics files and codes in this thread are included in the zip file below.
Last edited:
#### Remembermyname
Joined Sep 6, 2015
91
Awesome! Thank you!
#### MMcLaren
Joined Feb 14, 2010
845
I'm getting ready to try this out using a small multiplexed display from SparkFun and an ATMEGA328P-PU (Arduino "breadboard" configuration w/8-MHz internal oscillator). Just need to load your sketch and hook up a DS18B20. Once that is working I'll try to implement the PWM brightness control and pass along those results, if you're interested.
Cheerful regards, Mike
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https://www.tcs.tifr.res.in/events/classical-central-limit-theorem-wasserstein-metric | # The Classical Central Limit Theorem in Wasserstein Metric
Speaker:
## Time:
Friday, 19 September 2014, 14:00 to 15:30
## Venue:
• D-405 (D-Block Seminar Room)
## Organisers:
Abstract: We discuss a proof of the classical CLT (in Wasserstein metric) using Stein's Lemma. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9345079064369202, "perplexity": 8500.453339992564}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945279.63/warc/CC-MAIN-20230324082226-20230324112226-00300.warc.gz"} |
http://www.jguru.com/forums/view.jsp?EID=470799 | jGuru Forums
Using runtime.exec under windows '98.
0 posts in topic
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TOPIC ACTIONS:
Posted By: David_Abelson
Posted On: Tuesday, August 7, 2001 05:16 PM
I am trying to run a program called magma interactively under windows '98. My code is as follows: String [] command = { "c:\command.com", "/y", "/c" "magma", "-x", -b"}; Process p = Runtime.getRuntime().exec(command); InputStream is = p.getInputStream();..... This compiles and runs, but seems not to execute the command properly. It certainly isn't giving me a handle on the inputStream. How can one invoke correctly under '98? Thanks in advance More>>
I am trying to run a program called magma interactively
under windows '98.
My code is as follows:
```
String [] command = { "c:\command.com", "/y", "/c"
"magma", "-x", -b"};
Process p = Runtime.getRuntime().exec(command);
InputStream is = p.getInputStream();.....
```
This compiles and runs, but seems not to execute the command
properly. It certainly isn't giving me a handle on the inputStream.
How can one invoke correctly under '98?
Thanks in advance <<Less | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8582393527030945, "perplexity": 13920.246588557962}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-48/segments/1448398453553.36/warc/CC-MAIN-20151124205413-00265-ip-10-71-132-137.ec2.internal.warc.gz"} |
https://cs.stackexchange.com/questions/144735/attempting-to-verify-the-colorability-using-wigdersons-algorithm | # Attempting to verify the colorability using Wigderson's Algorithm
The algorithm of Wigderson (see here) can color a graph that is known to be $$3$$-colorable in $$O\left( \sqrt{\left| V \right|} \right)$$ colors. This is done in $$O\left( |V| + |E|\right)$$ time.
For those who are not familiar with the algorithm, I'll give a brief description of it (it can be used for any $$k$$-colorable graph, but lets assume $$k=3$$).
We loop on $$V$$ until a $$v\in V$$ is found such that $$\deg v \geq \sqrt {|V|}$$. If no such $$v\in V$$ exists, then the graph has a bounded degree of $$\sqrt{|V|}$$, and can be easily colored using $$\sqrt{|V|}$$ colors in linear time (by simply iterating over all vertices and selecting an unoccupied color among the ones of its neighbours).
Once such a $$v\in V$$ is found, we denote by $$G_v$$ the induced subgraph of $$v$$'s neighbours. As $$G$$ is $$3$$-colorable, $$G_v$$ is $$2$$-colorable. That means, $$G_v$$ can be colored using $$2$$ colors in linear time, by a simple "red"-"blue" algorithm. By selecting a third color, $$v$$ can be colored as well. Once we move to the next $$v\in V$$, we use a different color class (each color class contains $$3$$ colors).
We know that $$\left|V_{G_v}\right| \geq \sqrt{|V|}$$. Meaning, this procedure occurs for at most $$\frac{\left| V\right|}{\sqrt{\left| V\right|}} = \left| V \right|$$ iterations. The running time is linear each time, meaning the entire running time is still linear (in the original $$G$$).
So far is the algorithm. I would like to use in the following way:
Given a graph $$G=(V,E)$$, try coloring it using Wigderson's algorithm. If the graph is actually $$3$$-colorable, this will succeed. You will receive a $$O\left( \sqrt{\left| V \right|}\right)$$-coloring. If $$G$$ is not $$3$$-colorable, I believe this will fail because there should be at least one vertex $$v \in V$$ whose color, under any coloring function, cannot be among $$\left\{ 0,1,2 \right\}$$ (up to a permutation of the colors...). Meaning, under any coloring, its neighbours use all the colors $$\left\{ 0,1,2 \right\}$$ and the induced subgraph of its neighbours is not $$2$$-colorable. This means that when we try to $$2$$-color it by a simple "red"-"blue" algorithm, we will fail. So by checking whether or not we fail in Wigderson's Algorithm, can we not verify in reality whether $$G=(V,E)$$ is $$3$$-colorable or not?
I assume the answer is no, yet I'm looking for my mistake, and if possible, to elaborate on where exactly I am wrong in here.
Consider a star on $$n-4$$ vertices together with a clique on $$4$$ vertices.
• Yes, I see what's the problem is. Would you say that its correct to assume that $G$ is $3$-colorable iff the induced subgraph among all vertices with degree at least $\sqrt{\left| V\right|}$ can be colored as described by Wigderson's algorithm? Oct 13, 2021 at 11:38
• Actually, I can answer my own question: many cliques of size $4$ which are separate to one another. The graph is not $3$-colorable, but the induced subgraph is empty. Oct 13, 2021 at 11:39 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 40, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7920858860015869, "perplexity": 262.80005781860325}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710734.75/warc/CC-MAIN-20221130092453-20221130122453-00542.warc.gz"} |
https://socratic.org/organic-chemistry-1/ways-to-draw-and-represent-molecules/bond-line-notation | Organic Chemistry
Topics
# Bond Line Notation
## Key Questions
• Perhaps the first question one would ask when curious about organic chemistry!
An ethane molecule ${H}_{3} C - C {H}_{3}$ is merely,
Each terminal end has three hydrogens! It's that easy!
However, when we connect these lines into a chain or into a ring is when things may seem confusing. Consider propane and cyclopropane, respectively,
Where each line connects is a $C {H}_{2}$ group.
If there are substituents anywhere, you'd merely understand that it has one less hydrogen.
I remember when I started organic chemistry 1, we completely dropped Lewis structures by week 2! So getting this stuff very quick is important or organic chemist's drawings look like hieroglyphs.
• Yes, they are the same thing.
Click on the link to see examples of bond line notation.
Bond line notation is a shorthand way of writing organic structural formulas:
#### Explanation:
• The carbon atoms and the hydrogen atoms attached to them are not shown.
• Only the bonds between the carbon atoms are shown as lines.
• The vertices and end of lines represent the carbon atoms.
• Any unfilled valences on carbon are assumed to be filled by hydrogen atoms.
• All atoms other than carbon, plus any hydrogen atoms attached to them, are shown.
For example, the bond line notation for propane is
In the above diagram, the vertex and the ends of the lines represent the carbon atoms.
The two end C atoms each contain three H atoms, since they have each formed one bond to the middle C atom.
The middle C contains only two H atoms, since it has already formed two bonds with the other carbons.
Some more examples are shown below.
(i) ethylcyclopentane
(ii) heptane
(iii) 3-ethylpentane
(iv) 3-chloropentane
Here are still more bond line structures.
Note that we must show the H atoms that are attached to O and N atoms.
Here’s a video on bond line notation. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 2, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6694652438163757, "perplexity": 2589.015438714609}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376826145.69/warc/CC-MAIN-20181214162826-20181214184826-00596.warc.gz"} |
https://en.wikibooks.org/wiki/Set_Theory/Zermelo%E2%80%92Fraenkel_set_theory | # Set Theory/Zermelo‒Fraenkel set theory
1. Axiom of extensionality: ${\displaystyle \forall x,y:x=y\Leftrightarrow (z\in x\Leftrightarrow z\in y)}$
2. Empty set: ${\displaystyle \exists \emptyset :\forall x:x\notin \emptyset }$ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 2, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9255709648132324, "perplexity": 12892.578978213078}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-30/segments/1563195526536.46/warc/CC-MAIN-20190720153215-20190720175215-00138.warc.gz"} |
https://www.joshuapkeller.com/page/introregression/slrFtest.html | # Chapter 6 Inference for the SLR Model
$$\newcommand{\E}{\mathrm{E}}$$ $$\newcommand{\Var}{\mathrm{Var}}$$
In Chapter 4 we saw how to conduct inference about the parameters $$\beta_0$$ and $$\beta_1$$. That allowed to answer quesitons about the nature of the relationship between $$x_i$$ and $$y_i$$.
A related question we might ask is: Is the model useful overall? Rather than testing a specific parameter, this questions asks about the overall utility of the entire regression model. In this chapter, we explore how to address this question using F-tests.
## 6.1 Sum of Squares Decomposition
Decomposing the variability in the data provides the pieces necessary to assess overall model performance. The total variability in outcome for a specific dataset is given by the sample variance of the $$y_i$$’s. In regression this quantity is commonly called the total sum of squares:
$SS_{tot} = \displaystyle\sum_{i=1}^n(y_i - \overline{y})^2$
This is the sum of the squared distances between each observation and the overall mean, which can be visually represented by the sum of the squared lengths of the green lines in Figure 6.1.
The total sum of squares can be decomposed into two pieces:
\begin{align} \sum_{i=1}^n (y_i - \overline{y})^2 &= \sum_{i=1}^n \left(y_i - \hat y_i + \hat y_i - \overline{y}\right)^2 \notag\\ &= \sum_{i=1}^n (y_i - \hat y_i)^2 + 2 \sum_{i=1}^n(y_i - \hat y_i)(\hat y_i - \overline{y}) + \sum_{i=1}^n (\hat y_i - \overline y)^2 \notag\\ &= \sum_{i=1}^n (y_i - \hat y_i)^2 + 2 \sum_{i=1}^n(y_i - \hat y_i)\hat y_i \notag \\ & \qquad \qquad \qquad - 2 \sum_{i=1}^n(y_i - \hat y_i)\overline{y}+ \sum_{i=1}^n (\hat y_i - \overline y)^2 \notag\\ &= \sum_{i=1}^n (y_i - \hat y_i)^2 + \sum_{i=1}^n (\hat y_i - \overline y)^2 \tag{6.1} \end{align} The first term in (6.1) is called the residual sum of squares:
$SS_{res} = \sum_{i=1}^n (y_i - \hat y_i)^2$ This should look familiar–it is the same things as the sum of squared residuals ($$\sum_{i=1}^n e_i^2 = (n-2)\hat\sigma^2$$). This is variability “left over” from fitted regression model, and can be visualized as the sum of the squared distances in the following figure:
The other term in (6.1) is the regression sum of squares: $SS_{reg} = \sum_{i=1}^n (\hat y_i - \overline y)^2$. This is the variability that is explained by the regression model:
## 6.2 Coefficient of Determination ($$R^2$$)
One way to determine how “good” a model fit is, is to compute the proportion of variability in the outcome that is accounted for by the regression model. This can be represented by the following ratio:
$\frac{SS_{reg}}{SS_{tot}} = 1 - \frac{SS_{res}}{SS_{tot}} = R^2$ The quantity $$R^2$$ is commonly called the coefficient of determination. The denominator $$SS_{tot}$$ is a fixed quantity and the numerator $$SS_{reg}$$ can vary by model (i.e., by the chosen predictor variable). Larger values of $$R^2$$ mean that greater amounts of variability in the outcome is explained by the model. When there are multiple predictor variables in a model, we will need to use an alternative form of $$R^2$$ (see Section 10.7).
Since the amount of variation explained by the model cannot be greater than the total variation in the outcome, $$R^2$$ must lie between 0 and 1. The range of $$R^2$$ values corresponding to a “good” or “bad” model fit varies by context. In most settings, values above 0.8 represent a “good” model. But in some contexts, $$R^2$$ as low as 0.3 can be “good”. What is “good” for prediction may differ from what is “good” for learning about the underlying science, and vice versa. Making a qualitative judgment about $$R^2$$ requires familiarity with what is typical for the type of data being analyzed.
R will compute the value of $$R^2$$ for you in the output from summary():
penguin_lm <- lm(body_mass_g~flipper_length_mm,
data=penguins)
summary(penguin_lm)
##
## Call:
## lm(formula = body_mass_g ~ flipper_length_mm, data = penguins)
##
## Residuals:
## Min 1Q Median 3Q Max
## -1058.80 -259.27 -26.88 247.33 1288.69
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) -5780.831 305.815 -18.90 <2e-16 ***
## flipper_length_mm 49.686 1.518 32.72 <2e-16 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 394.3 on 340 degrees of freedom
## (2 observations deleted due to missingness)
## Multiple R-squared: 0.759, Adjusted R-squared: 0.7583
## F-statistic: 1071 on 1 and 340 DF, p-value: < 2.2e-16
The value of $$R^2$$ is listed as Multiple R-squared: 0.759 in the second line from the bottom. Adjusted $$R^2$$ will be discussed in Section 10.7.
## 6.3 F-Test for Regression
In regression, we can ask whether there is an overall linear relationship between the predictor variable and the average values of the outcome variable. This is commonly called a test for significance of regression or a global F-test, and the corresponding null and alternative hypotheses are:
• $$H_0 =$$ There is no linear relationship between the $$x$$’s and the average value of $$y$$
• $$H_A =$$ There is a linear relationship between the $$x$$’s and the average value of $$y$$
In SLR there is only one $$x$$ variable, so this is exactly equivalent to testing $$H_0: \beta_1 = 0$$ vs. $$H_A: \beta_1 \ne 0$$. However, when there are multiple predictor variables in the model, the global F-test and a test for a single $$\beta$$ parameter are no longer the same (see Section 10.5).
The test statistic for the test for significance of regression is:
$$$\label{eq:slrfstat} f = \frac{MS_{reg}}{MS_{res}} = \frac{SS_{reg}/df_{reg}}{SS_{res}/df_{res}} = \frac{SS_{reg}/1}{SS_{res}/(n-2)}$$$
In equation (??), the statistic can be heuristically thought of as a signal-to-noise ratio. The numerator $$SS_{reg}/1$$ is the average amount of variabiliy explained by each predictor variable, which is a measure of “signal”. The denominator $$SS_{res}/(n-2)$$ is the average amount of variability left unexplained, which is a measure of “noise”.
When the value of $$f$$ is large enough, we conclude that the variability explained by the model is sufficiently larger than the variability left unexplained. Thus, we use a one-sided test and reject $$H_0$$ if $$f$$ is large enough. If the null hypothesis is true and the $$\epsilon_i$$ are normally distributed,8 then $$f$$ follows an $$F$$ distribution with 1 and $$n-2$$ degrees of freedom, i.e., $$f \sim F_{1, n-2}$$.
### 6.3.1 F-test in R “by hand”
Example 6.1 In the penguin data from Example 4.7, is there a linear relationship between flipper length and body mass?
To answer this using a global F-test, we set up the null and alternative hypotheses as:
$$H_0 =$$ There is no linear relationship between penguin flipper length and average body mass. $$H_A =$$ There is a linear relationship between penguin flipper length and average body mass.
We now need to compute $$SS_{res}$$:
SSres <- sum(residuals(penguin_lm)^2)
SSres
## [1] 52854796
and $$SS_{reg}$$:
SSreg <- sum((fitted(penguin_lm) - mean(penguin_lm$model$body_mass_g))^2)
SSreg
## [1] 166452902
Note that when computing $$SS_{reg}$$ in this way, we are using penguin_lm$model$body_mass_g rather than penguins\$body_mass_g. This is because the version of body mass stored within the penguin_lm object will contain exactly the observations used to fit the model. This can be important if there is missing data that lm() drops automatically.
With both $$SS_{res}$$ and $$SS_{reg}$$ calculated, we can compute the F-statistic:
f <- (SSreg/1)/(SSres/(nobs(penguin_lm)- 2))
f
## [1] 1070.745
and $$p$$-value (being careful to set lower=FALSE to do a one-sided test):
pf(f, df1=1, df2=nobs(penguin_lm)- 2, lower=FALSE)
## [1] 4.370681e-107
### 6.3.2 F-test in R
Of course, it is faster and simpler to let R compute the F-statistic and $$p$$-value for you. This information is available at the bottom of the output from summary():
summary(penguin_lm)
##
## Call:
## lm(formula = body_mass_g ~ flipper_length_mm, data = penguins)
##
## Residuals:
## Min 1Q Median 3Q Max
## -1058.80 -259.27 -26.88 247.33 1288.69
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) -5780.831 305.815 -18.90 <2e-16 ***
## flipper_length_mm 49.686 1.518 32.72 <2e-16 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 394.3 on 340 degrees of freedom
## (2 observations deleted due to missingness)
## Multiple R-squared: 0.759, Adjusted R-squared: 0.7583
## F-statistic: 1071 on 1 and 340 DF, p-value: < 2.2e-16
Regardless of which approach to calculating the test statistic that we use, we can summarize our conclusions by saying:
We reject the null hypothesis that there is no linear relationship between penguin flipper length and average body mass ($$p < 0.0001$$).
## 6.4 ANOVA Table
$$F$$-tests are widely used in the Analysis of Variance (ANOVA) approach to analyzing data. Information can be summarized in an “ANOVA Table”:
Source of Variation Sum of Squares Degrees of Freedom MS F
Regression $$SS_{reg}$$ $$1$$ $$MS_{reg}$$ $$MS_{reg}/MS_{res}$$
Residual $$SS_{res}$$ $$n-2$$ $$MS_{res}$$
Total $$SS_{tot}$$ $$n-1$$
This format arises most frequently for designed experiments, where there is a rich history of decomposing the variability of data into distinct sources.
1. In many cases, it is sufficient for sample sizes to be large so that the central limit theorem applies. But care should be taken in small samples.↩︎ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 2, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 1, "equation": 1, "x-ck12": 0, "texerror": 0, "math_score": 0.9475100040435791, "perplexity": 797.4222416025431}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-21/segments/1620243988923.22/warc/CC-MAIN-20210508181551-20210508211551-00106.warc.gz"} |
https://docs.nvidia.com/drive/archive/driveworks-3.0/dwx_camera_calibration.html | DriveWorks SDK Reference 3.0.4260 Release For Test and Development only
Static Camera Calibration
Note
SW Release Applicability: This tutorial is applicable to modules in both NVIDIA DriveWorks and NVIDIA DRIVE Software releases.
The NVIDIA® Static Camera Calibration tutorial describes how to perform intrinsic and extrinsic calibration for a vehicle's cameras using the DriveWorks Static Calibration Tools.
The step-by-step tutorial covers the following:
# 1.0 Prerequisites
The following cameras and targets are required before proceeding in this tutorial.
## 1.1 Cameras
The following cameras are required for calibration:
#### AV Cameras
• N number of fixed focal length cameras. In this tutorial, 12 AR0231 cameras are used as an example.
• Cameras are mounted on vehicle or otherwise not expected to be purposely moved after completion of this tutorial.
• Referred to as "camera" or "cameras" throughout the remainder of this tutorial.
#### One Camera to support AV camera calibration
• Fixed focal length of roughly 18mm-30mm.
• At least 12MP resolution.
• Sensor size to be roughly Canon's ASP-C or Nikon's DX size (roughly 23mmx15mm).
• Referred to as "external camera" throughout the remainder of this tutorial.
## 1.2 Targets
This tutorial requires the use of targets to calibrate the vehicle's cameras.
The targets used in this tutorial can be found in the following folder:
data/tools/calibration/aprilTargets
An example of the target used in this tutorial:
Calibration Targets
### 1.2.1 Target Prints
The targets must be printed as follows:
#### 8 large targets (or more)
• Size 1m x 1m.
• Target IDs 89-101 in data/tools/calibration/aprilTargets.
#### 4 small targets
• A3 format.
• Target IDs 180-183 in data/tools/calibration/aprilTargets.
Note
A target with the same ID cannot be reused multiple times.
Although not recommended, it is possible to use targets other than the ones provided with the Static Calibration Tools.
### 1.2.2 Target Print Validation
For each target, measure the length of the horizontal bar in millimeters (mm) and note it in the corner, as demonstrated in the above image.
Note
Ensure the printouts have correct aspect ratios by comparing the length of the vertical and horizontal bars.
If their lengths are not equal, the targets MUST be reprinted, as they do not have the correct aspect ratio.
Additionally, ensure the targets are perfectly flat, rigid, and do not bend.
# 2.0 Scene Setup
## 2.1 Camera Placement
Depending on the number and location of the cameras on the vehicle, different scene setups may be used.
In this tutorial, a setup with 12 cameras mounted on a car roof is used as an example.
## 2.2 Target Placement
Ensure the following constraints when placing targets during scene setup:
• The 4 small targets are placed on the wheels, and that the target centers and wheel centers are aligned.
• Each camera requiring calibration must observe at least 1 large target.
• Each target covers the camera's field of view as much as possible.
• Each target is present only once in the scene.
In this tutorial, a set of 8 large and 4 small targets are used as an example.
Ideal Target Placement
Example Target Placement
# 3.0 Capturing Data
The following types of data must be captured for static camera calibration:
• Intrinsic Data: This only needs to be captured once if camera parameters i.e., lens, have not changed.
• Extrinsic Data: Includes images captured from the vehicle's cameras to be calibrated and images captured with the external camera.
## 3.1 Capturing Data for Intrinsic Camera Calibration
To capture data for intrinsic camera calibration:
1. Move a checkerboard pattern or AprilTag target in front of each camera requiring calibration.
AprilTag in front of camera
2. Setup and start the Recorder for all cameras requiring calibration. Refer to Basic Recording for more information how to setup recorder.
Note
To save disc space setup recorder to record h264/mp4 stream directly, e.g. by passing format=h264,output-format=yuv as camera sensor properties.
3. While the recorder is running, perform the following for each camera:
• Move the checkerboard pattern from left to right in front of the camera.
• While moving, rotate the pattern in all dimensions to calibrate pitch, roll, and yaw.
• While moving, get closer and further away from the camera to calibrate scale.
• Stop periodically while moving to allow motion-blur free constraint detection.
The calibration tool will automatically extract all valid frames from the recorded video.
Refer to 4.2 Intrinsic Camera Calibration.
## 3.2 Capturing Data for Extrinsic Camera Calibration
To capture data for extrinsic camera calibration, use one of the following methods to capture one image from each car camera:
### 3.2.1 Using the DriveWorks Recorder
Use the DriveWorks Recorder Tool to simultaneously record video from all cameras and ffmpeg to extract one frame from the video.
1. Setup the Driveworks Recorder Tool as described in Basic Recording (use h264/mp4 recording)
2. Extract individual frames with ffmpeg:
ffmpeg -i \<folder\>/camera_X.h264 -t 1 -f image2 camera_X.png
### 3.2.2 Using the DriveWorks Sample
Use the DriveWorks Sample sample_camera_multiple_gmsl to capture a frame.
1. For 12 cameras of the same type execute:
./sample_camera_multiple_gmsl --selector-mask=111111111111
2. Press F while the sample is running to capture a frame from each camera as a .png file.
Once you have followed one of the two methods described above, rename and copy the files to an appropriate location as indicated by the DriveWorks Calibration Tools.
In addition to capturing frames from the vehicle's cameras, a set of images also needs to be captured with the external camera.
These images help construct a calibration graph as they introduce a link between targets not observable by the car cameras.
These targets can include ground targets, wheel targets, and between targets of individual cameras.
It is recommended you capture at least 20 images with the external camera, so that all possible target pairs are recorded.
Ensure these images simultaneously observe both the ground targets, and the wheel targets.
The following demonstrates the types of images to capture with the external camera:
Images to Capture with the External Camera
Note
It is not required to perform intrinsic calibration for the external camera. Targets detected in the frame will be automatically used for intrinsic constraints.
Therefore, it is important that there are at least 20 images provided for the external camera.
# 4.0 Using the Calibration Tools
The Static Calibration Tool suite consists of multiple command line tools. This tutorial covers the tools required for static calibration of the vehicle's cameras. There are additional calibration tools for auxiliary support and additional sensor. These are not covered in this tutorial. All tools used in this section are documented in Camera Calibration Tools.
Note
It is recommended to run the calibration tool suite on an x86 Host System due to the resource requirements of the internal optimization.
## 4.1 Directory Structure
The calibration tools expect a specific directory structure as well as a predefined collection of files:
<calib-data-path>
|-- targets.json The target database with the measured bar lengths
|-- special-targets.json List all special targets in this file
|-- intrinsics Constraints generated using intrinsic tool
| |-- <camera-0>.json
| |-- ...
| |-- <camera-N>.json
|
|-- extrinsics Images captured by car cameras
| |-- <camera-0>.[png/jpg] NOTE: names of the files must match the .json
| |-- ... file names from the intrinsic/ folder
| |-- <camera-N>.[png/jpg]
|
|-- external Images captured by external camera
| |-- <image-0>.[png/jpg/JPG] NOTE: names of the images are irrelevant
| |-- ...
| |-- <image-M>.[png/jpg/JPG]
### 4.1.1 targets.json
targets.json is a target database shipped with DriveWorks. It contains all the large targets that can be used in the scene.
Modify this file and change the barLength fields for all targets in the scene to the length (in meters) which you measured in 1.2.1 Target Prints.
### 4.1.2 special-targets.json
special-targets.json: The targets attached to the wheels and the targets that lie flat on the floor must also be declared in this file.
The structure of this file is as follows:
{
"ground_targets": [99,100],
"ignore_targets": [142],
"wheel_targets":
{
"rearLeft": 181,
"rearRight": 182,
"frontLeft": 180,
"frontRight": 183
}
}
Ensure that the targets which are on the ground and which are attached to the wheels are correctly identified in this file.
## 4.2 Intrinsic Camera Calibration
This section requires the usage of the DriveWorks Intrinsics Constraints Tool, to extract intrinsics constraints used during calibration for each individual camera.
The input for this tool is the video recorded in 3.1 Capturing Data for Intrinsic Camera Calibration.
This tool will then export all required constraints and output them in a .json file to be placed in the /intrinsics/ subfolder in the directory structure.
### 4.2.1 For an 11x8 Checkerboard
Run the tool by executing:
./calibration-intrinsics-constraints
--use-checkerboard=11x8
--input-video=<video_path>/camera-0.h264
--output=<calib_data_path>/intrinsics/camera-0.json
### 4.2.2 For an AprilTag Target Video
Run the tool by executing:
./calibration-intrinsics-constraints
--targetDB=<calib_data_path>/targets.json
--input-video=<video_path>/camera-0.h264
--output=<calib_data_path>/intrinsics/camera-0.json
The tool will open a window playing back the input video and indicate with a red or green border if a new intrinsic constraint has been collected (i.e. target or checkerboard has been found).
Intrinsics Constraints Output
Note
It is important that the tool is able to find at least 30 constraints (checkerboards or AprilTags) per camera.
## 4.3 Extrinsic Calibration
This section requires the usage of the DriveWorks Graph Calibration Tool, to construct a graph-based representation of the data obtained, which is then further optimized.
Running this tool without parameters assumes you have the file structure specified in 4.1 Directory Structure.
The tool determines the names of the cameras from the extrinsics folder. It then searches the intrinsic folder for .json files corresponding with the intrinsics constraints.
The images captured with the external camera will also be used for intrinsic calibration for the external camera, and for extrinsics constraints.
The Calibration Tool will then use these images to construct a graph representation which is later optimized.
### 4.3.1 Extrinsic Calibration Setup
Ensure the following before proceeding:
### 4.3.2 Extrinsic Calibration Execution
Run the tool by executing the following:
./calibration-graph-cli --dir=<calib_data_path>
The tool outputs progress to the console. Take note of warnings in yellow and errors in red as they indicate possible problems with the calibration.
The following outputs are placed in the target folder:
• calibrated-graph.json is the main output for this tool. This contains all constraints, the calibrated camera models, the camera poses, the target poses, etc.
This is an intermediate format which is meant for machine consumption only.
• Intrinsic validation images show the set of points used for intrinsic calibration:
• Blue dots = detected.
• Red dots = reprojected.
• Small yellow lines = line joining detection and re-projection.
• Large yellow lines = outliers.
The output is generated for all car cameras, (validation-intrinsics-<camera>.jpg) and the external cameras.
Intrinsic Validation Output
• Extrinsic validation images show the image used for extrinsic calibration with overlaid results, where:
• Detected targets have a green overlay.
• Detected tags have their corner detections with the same colors as their intrinsic re-projections.
• The ground plane is drawn as a series of green lines 1 meter apart. The lines at x = 0 and y = 0 are orange.
The output is generated for all car cameras, and each external image (validation-<camera>.jpg).
Extrinsic Validation Output
### 4.3.3 Extrinsic Calibration Validation
Validation images can be used to double check if the computed calibration is valid, i.e., if the green re-projections match the targets.
In the following image, a green mask clearly overlays the targets, and the corners are well aligned. This indicates a valid computed calibration.
Valid Calibration
In the following image, a green mask is misaligned with the target. This indicates the calibration results might not be correct, or that there is a problem with the calibration target.
Invalid Calibration
Note
In most cases an invalid re-projection of the calibration mask occurs when:
• Intrinsic calibration is not well constrained. This occurs if the checkerboard or target was not adequately covering the camera field of view during intrinsic calibration. As an example, intrinsic validation images contain points that are well-detected and spread all over.
• Target corner detection failed or is not precise. This may occur if the image is blurry or low quality.
• Targets are not flat. This is the most likely reason for the misalignment. Ensure that all targets are flat, rigid, and do not bend, to prevent these issues.
## 4.4 Generating DriveWorks rig.json File
The Graph Calibration Tool also provides a calibrated-graph.json file as output. This file contains intermediate
calibration results which cannot yet be consumed by the NVIDIA® DriveWorks SDK. These results can be converted using the Calibrated Graph Tool into a valid DriveWorks SDK rig.json file representing the full calibrated camera rig configuration, and can be directly consumed by the DriveWorks modules, e.g., Rig Configuration.
To perform the conversion, run the tool by executing the following:
./calibration-graph-to-rig --graph=<calib_data_path>/calibrated-graph.json
The tool generates a rig.json file in the current folder. This file lists all cameras used during calibration with their final intrinsic and extrinsic calibration data.
{
"rig": {
"sensors": [
{
"name": "CameraA",
"protocol": "camera",
"parameter": "",
"properties": {
"Model": "pinhole",
"cx": "960.00000",
"cy": "604.00000",
"distortion": "-3.38998615741730e-1 2.48174026608467e-1 0.000000000000000 ",
"fx": "1829.0598",
"fy": "1150.4340",
"height": "1208",
"width": "1920"
},
"correction_rig_T": [
0.0,
0.0,
0.0
],
"correction_sensor_R_FLU": {
"roll-pitch-yaw": [
-2.9311993804404e-11,
1.66752689434446e-09,
-6.67010668919943e-09
]
},
"nominalSensor2Rig_FLU": {
"roll-pitch-yaw": [
0.00125622225459665,
-0.0149850230664015,
0.0607732236385345
],
"t": [
1.5044356584549,
-0.00227832840755582,
1.49242639541626
]
}
},
...
],
"vehicle": {
"valid": false,
"value": {
"axlebaseFront": 0.0,
"axlebaseRear": 0.0,
"bumperFront": 0.0,
"bumperRear": 0.0,
"centerOfMassToRearAxle": 0.0,
"driveByWireTimeConstant": 0.0,
"driveByWireTimeDelay": 0.0,
"frontCorneringStiffness": 0.0,
"height": 0.0,
"inertia": 0.0,
"length": 0.0,
"mass": 0.0,
"rearCorneringStiffness": 0.0,
"steeringCoefficient": 0.0,
"wheelDiameter": 0.0,
"wheelbase": 0.0,
"width": 0.0,
"widthWithMirrors": 0.0
}
}
},
"version": 2
}
If an existing rig.json is passed as input, all camera entries are modified with the new calibration results.
Note
The coordinate system conventions used by the calibration tools can be found in Coordinate Systems.
# 5.0 Additional Information
## 5.1 Intrinsic-only Calibration
The Static Calibration Tool suite supports calibration for intrinsic parameters only, if extrinsic calibration is not desired or required.
The procedure is similar to the full calibration workflow, with several modifications:
1. Record videos with the checkerboard or AprilTag patterns described in 3.1 Capturing Data for Intrinsic Camera Calibration.
2. Create the directory structure as described in 4.1 Directory Structure. Only include the intrinsics folder and targets.json file.
3. For each camera, execute the intrinsic calibration application. This generates a set of .json files for each camera.
4. Execute the Graph Calibration Tool as demonstrated in 4.3.2 Extrinsic Calibration Execution.
• This generates a calibrated-graph.json file in the input directory, and intrinsic validation images as demonstrated in the section. Verify that these validation images meet the requirements described above.
5. Execute the Calibrated Graph to Rig File Tool to populate a rig.json file with the result. Refer to 4.4 Generating DriveWorks rig.json File for more information. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.16632810235023499, "perplexity": 5221.2885070536495}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780058456.86/warc/CC-MAIN-20210927151238-20210927181238-00384.warc.gz"} |
http://doc.sagemath.org/html/en/reference/categories/sage/categories/semigroups.html | # Semigroups¶
class sage.categories.semigroups.Semigroups(base_category)
The category of (multiplicative) semigroups.
A semigroup is an associative magma, that is a set endowed with a multiplicative binary operation $$*$$ which is associative (see Wikipedia article Semigroup).
The operation $$*$$ is not required to have a neutral element. A semigroup for which such an element exists is a monoid.
EXAMPLES:
sage: C = Semigroups(); C
Category of semigroups
sage: C.super_categories()
[Category of magmas]
sage: C.all_super_categories()
[Category of semigroups, Category of magmas,
Category of sets, Category of sets with partial maps, Category of objects]
sage: C.axioms()
frozenset({'Associative'})
sage: C.example()
An example of a semigroup: the left zero semigroup
class Algebras(category, *args)
class ParentMethods
algebra_generators()
The generators of this algebra, as per MagmaticAlgebras.ParentMethods.algebra_generators().
They correspond to the generators of the semigroup.
EXAMPLES:
sage: M = FiniteSemigroups().example(); M
An example of a finite semigroup:
the left regular band generated by ('a', 'b', 'c', 'd')
sage: M.semigroup_generators()
Family ('a', 'b', 'c', 'd')
sage: M.algebra(ZZ).algebra_generators()
Finite family {0: B['a'], 1: B['b'], 2: B['c'], 3: B['d']}
gen(i=0)
Return the i-th generator of self.
EXAMPLES:
sage: A = GL(3, GF(7)).algebra(ZZ)
sage: A.gen(0)
[3 0 0]
[0 1 0]
[0 0 1]
gens()
Return the generators of self.
EXAMPLES:
sage: a, b = SL2Z.algebra(ZZ).gens(); a, b
([ 0 -1]
[ 1 0],
[1 1]
[0 1])
sage: 2*a + b
2*[ 0 -1]
[ 1 0]
+
[1 1]
[0 1]
ngens()
Return the number of generators of self.
EXAMPLES:
sage: SL2Z.algebra(ZZ).ngens()
2
sage: DihedralGroup(4).algebra(RR).ngens()
2
product_on_basis(g1, g2)
Product, on basis elements, as per MagmaticAlgebras.WithBasis.ParentMethods.product_on_basis().
The product of two basis elements is induced by the product of the corresponding elements of the group.
EXAMPLES:
sage: S = FiniteSemigroups().example(); S
An example of a finite semigroup: the left regular band generated by ('a', 'b', 'c', 'd')
sage: A = S.algebra(QQ)
sage: a,b,c,d = A.algebra_generators()
sage: a * b + b * d * c * d
B['ab'] + B['bdc']
regular_representation(side='left')
Return the regular representation of self.
INPUT:
• side – (default: "left") whether this is the "left" or "right" regular representation
EXAMPLES:
sage: G = groups.permutation.Dihedral(4)
sage: A = G.algebra(QQ)
sage: V = A.regular_representation()
sage: V == G.regular_representation(QQ)
True
trivial_representation(side='twosided')
Return the trivial representation of self.
INPUT:
• side – ignored
EXAMPLES:
sage: G = groups.permutation.Dihedral(4)
sage: A = G.algebra(QQ)
sage: V = A.trivial_representation()
sage: V == G.trivial_representation(QQ)
True
extra_super_categories()
Implement the fact that the algebra of a semigroup is indeed a (not necessarily unital) algebra.
EXAMPLES:
sage: Semigroups().Algebras(QQ).extra_super_categories()
[Category of semigroups]
sage: Semigroups().Algebras(QQ).super_categories()
[Category of associative algebras over Rational Field,
Category of magma algebras over Rational Field]
Aperiodic
class CartesianProducts(category, *args)
extra_super_categories()
Implement the fact that a Cartesian product of semigroups is a semigroup.
EXAMPLES:
sage: Semigroups().CartesianProducts().extra_super_categories()
[Category of semigroups]
sage: Semigroups().CartesianProducts().super_categories()
[Category of semigroups, Category of Cartesian products of magmas]
class ElementMethods
Finite
FinitelyGeneratedAsMagma
HTrivial
JTrivial
LTrivial
class ParentMethods
cayley_graph(side='right', simple=False, elements=None, generators=None, connecting_set=None)
Return the Cayley graph for this finite semigroup.
INPUT:
• side – “left”, “right”, or “twosided”: the side on which the generators act (default:”right”)
• simple – boolean (default:False): if True, returns a simple graph (no loops, no labels, no multiple edges)
• generators – a list, tuple, or family of elements of self (default: self.semigroup_generators())
• connecting_set – alias for generators; deprecated
• elements – a list (or iterable) of elements of self
OUTPUT:
EXAMPLES:
sage: D4 = DihedralGroup(4); D4
Dihedral group of order 8 as a permutation group
sage: G = D4.cayley_graph()
sage: show(G, color_by_label=True, edge_labels=True)
sage: A5 = AlternatingGroup(5); A5
Alternating group of order 5!/2 as a permutation group
sage: G = A5.cayley_graph()
sage: G.show3d(color_by_label=True, edge_size=0.01, edge_size2=0.02, vertex_size=0.03)
sage: G.show3d(vertex_size=0.03, edge_size=0.01, edge_size2=0.02, vertex_colors={(1,1,1):G.vertices()}, bgcolor=(0,0,0), color_by_label=True, xres=700, yres=700, iterations=200) # long time (less than a minute)
sage: G.num_edges()
120
sage: w = WeylGroup(['A',3])
sage: d = w.cayley_graph(); d
Digraph on 24 vertices
sage: d.show3d(color_by_label=True, edge_size=0.01, vertex_size=0.03)
Alternative generators may be specified:
sage: G = A5.cayley_graph(generators=[A5.gens()[0]])
sage: G.num_edges()
60
sage: g=PermutationGroup([(i+1,j+1) for i in range(5) for j in range(5) if j!=i])
sage: g.cayley_graph(generators=[(1,2),(2,3)])
Digraph on 120 vertices
If elements is specified, then only the subgraph induced and those elements is returned. Here we use it to display the Cayley graph of the free monoid truncated on the elements of length at most 3:
sage: M = Monoids().example(); M
An example of a monoid: the free monoid generated by ('a', 'b', 'c', 'd')
sage: elements = [ M.prod(w) for w in sum((list(Words(M.semigroup_generators(),k)) for k in range(4)),[]) ]
sage: G = M.cayley_graph(elements = elements)
sage: G.num_verts(), G.num_edges()
(85, 84)
sage: G.show3d(color_by_label=True, edge_size=0.001, vertex_size=0.01)
We now illustrate the side and simple options on a semigroup:
sage: S = FiniteSemigroups().example(alphabet=('a','b'))
sage: g = S.cayley_graph(simple=True)
sage: g.vertices()
['a', 'ab', 'b', 'ba']
sage: g.edges()
[('a', 'ab', None), ('b', 'ba', None)]
sage: g = S.cayley_graph(side="left", simple=True)
sage: g.vertices()
['a', 'ab', 'b', 'ba']
sage: g.edges()
[('a', 'ba', None), ('ab', 'ba', None), ('b', 'ab', None),
('ba', 'ab', None)]
sage: g = S.cayley_graph(side="twosided", simple=True)
sage: g.vertices()
['a', 'ab', 'b', 'ba']
sage: g.edges()
[('a', 'ab', None), ('a', 'ba', None), ('ab', 'ba', None),
('b', 'ab', None), ('b', 'ba', None), ('ba', 'ab', None)]
sage: g = S.cayley_graph(side="twosided")
sage: g.vertices()
['a', 'ab', 'b', 'ba']
sage: g.edges()
[('a', 'a', (0, 'left')), ('a', 'a', (0, 'right')), ('a', 'ab', (1, 'right')), ('a', 'ba', (1, 'left')), ('ab', 'ab', (0, 'left')), ('ab', 'ab', (0, 'right')), ('ab', 'ab', (1, 'right')), ('ab', 'ba', (1, 'left')), ('b', 'ab', (0, 'left')), ('b', 'b', (1, 'left')), ('b', 'b', (1, 'right')), ('b', 'ba', (0, 'right')), ('ba', 'ab', (0, 'left')), ('ba', 'ba', (0, 'right')), ('ba', 'ba', (1, 'left')), ('ba', 'ba', (1, 'right'))]
sage: s1 = SymmetricGroup(1); s = s1.cayley_graph(); s.vertices()
[()]
Todo
• Add more options for constructing subgraphs of the Cayley graph, handling the standard use cases when exploring large/infinite semigroups (a predicate, generators of an ideal, a maximal length in term of the generators)
• Specify good default layout/plot/latex options in the graph
• Generalize to combinatorial modules with module generators / operators
AUTHORS:
• Bobby Moretti (2007-08-10)
• Robert Miller (2008-05-01): editing
• Nicolas M. Thiery (2008-12): extension to semigroups, side, simple, and elements options, …
magma_generators()
An alias for semigroup_generators().
EXAMPLES:
sage: S = Semigroups().example("free"); S
An example of a semigroup: the free semigroup generated by ('a', 'b', 'c', 'd')
sage: S.magma_generators()
Family ('a', 'b', 'c', 'd')
sage: S.semigroup_generators()
Family ('a', 'b', 'c', 'd')
prod(args)
Return the product of the list of elements args inside self.
EXAMPLES:
sage: S = Semigroups().example("free")
sage: S.prod([S('a'), S('b'), S('c')])
'abc'
sage: S.prod([])
Traceback (most recent call last):
...
AssertionError: Cannot compute an empty product in a semigroup
regular_representation(base_ring=None, side='left')
Return the regular representation of self over base_ring.
• side – (default: "left") whether this is the "left" or "right" regular representation
EXAMPLES:
sage: G = groups.permutation.Dihedral(4)
sage: G.regular_representation()
Left Regular Representation of Dihedral group of order 8
as a permutation group over Integer Ring
semigroup_generators()
Return distinguished semigroup generators for self.
OUTPUT: a family
This method is optional.
EXAMPLES:
sage: S = Semigroups().example("free"); S
An example of a semigroup: the free semigroup generated by ('a', 'b', 'c', 'd')
sage: S.semigroup_generators()
Family ('a', 'b', 'c', 'd')
subsemigroup(generators, one=None, category=None)
Return the multiplicative subsemigroup generated by generators.
INPUT:
• generators – a finite family of elements of self, or a list, iterable, … that can be converted into one (see Family).
• one – a unit for the subsemigroup, or None.
• category – a category
This implementation lazily constructs all the elements of the semigroup, and the right Cayley graph relations between them, and uses the latter as an automaton.
See AutomaticSemigroup for details.
EXAMPLES:
sage: R = IntegerModRing(15)
sage: M = R.subsemigroup([R(3),R(5)]); M
A subsemigroup of (Ring of integers modulo 15) with 2 generators
sage: M.list()
[3, 5, 9, 0, 10, 12, 6]
By default, $$M$$ is just in the category of subsemigroups:
sage: M in Semigroups().Subobjects()
True
In the following example, we specify that $$M$$ is a submonoid of the finite monoid $$R$$ (it shares the same unit), and a group by itself:
sage: M = R.subsemigroup([R(-1)],
....: category=Monoids().Finite().Subobjects() & Groups()); M
A submonoid of (Ring of integers modulo 15) with 1 generators
sage: M.list()
[1, 14]
sage: M.one()
1
In the following example $$M$$ is a group; however its unit does not coincide with that of $$R$$, so $$M$$ is only a subsemigroup, and we need to specify its unit explicitly:
sage: M = R.subsemigroup([R(5)],
....: category=Semigroups().Finite().Subobjects() & Groups()); M
Traceback (most recent call last):
...
ValueError: For a monoid which is just a subsemigroup, the unit should be specified
sage: M = R.subsemigroup([R(5)], one=R(10),
....: category=Semigroups().Finite().Subobjects() & Groups()); M
A subsemigroup of (Ring of integers modulo 15) with 1 generators
sage: M in Groups()
True
sage: M.list()
[10, 5]
sage: M.one()
10
Todo
• Fix the failure in TESTS by providing a default implementation of __invert__ for finite groups (or even finite monoids).
• Provide a default implementation of one for a finite monoid, so that we would not need to specify it explicitly?
trivial_representation(base_ring=None, side='twosided')
Return the trivial representation of self over base_ring.
INPUT:
• base_ring – (optional) the base ring; the default is $$\ZZ$$
• side – ignored
EXAMPLES:
sage: G = groups.permutation.Dihedral(4)
sage: G.trivial_representation()
Trivial representation of Dihedral group of order 8
as a permutation group over Integer Ring
class Quotients(category, *args)
class ParentMethods
semigroup_generators()
Return semigroup generators for self by retracting the semigroup generators of the ambient semigroup.
EXAMPLES:
sage: S = FiniteSemigroups().Quotients().example().semigroup_generators() # todo: not implemented
example()
Return an example of quotient of a semigroup, as per Category.example().
EXAMPLES:
sage: Semigroups().Quotients().example()
An example of a (sub)quotient semigroup: a quotient of the left zero semigroup
RTrivial
class SubcategoryMethods
Aperiodic()
Return the full subcategory of the aperiodic objects of self.
A (multiplicative) semigroup $$S$$ is aperiodic if for any element $$s\in S$$, the sequence $$s,s^2,s^3,...$$ eventually stabilizes.
In terms of variety, this can be described by the equation $$s^\omega s = s$$.
EXAMPLES:
sage: Semigroups().Aperiodic()
Category of aperiodic semigroups
An aperiodic semigroup is $$H$$-trivial:
sage: Semigroups().Aperiodic().axioms()
frozenset({'Aperiodic', 'Associative', 'HTrivial'})
In the finite case, the two notions coincide:
sage: Semigroups().Aperiodic().Finite() is Semigroups().HTrivial().Finite()
True
HTrivial()
Return the full subcategory of the $$H$$-trivial objects of self.
Let $$S$$ be (multiplicative) semigroup. Two elements of $$S$$ are in the same $$H$$-class if they are in the same $$L$$-class and in the same $$R$$-class.
The semigroup $$S$$ is $$H$$-trivial if all its $$H$$-classes are trivial (that is of cardinality $$1$$).
EXAMPLES:
sage: C = Semigroups().HTrivial(); C
Category of h trivial semigroups
sage: Semigroups().HTrivial().Finite().example()
NotImplemented
JTrivial()
Return the full subcategory of the $$J$$-trivial objects of self.
Let $$S$$ be (multiplicative) semigroup. The $$J$$-preorder $$\leq_J$$ on $$S$$ is defined by:
$x\leq_J y \qquad \Longleftrightarrow \qquad x \in SyS$
The $$J$$-classes are the equivalence classes for the associated equivalence relation. The semigroup $$S$$ is $$J$$-trivial if all its $$J$$-classes are trivial (that is of cardinality $$1$$), or equivalently if the $$J$$-preorder is in fact a partial order.
EXAMPLES:
sage: C = Semigroups().JTrivial(); C
Category of j trivial semigroups
A semigroup is $$J$$-trivial if and only if it is $$L$$-trivial and $$R$$-trivial:
sage: sorted(C.axioms())
['Associative', 'HTrivial', 'JTrivial', 'LTrivial', 'RTrivial']
sage: Semigroups().LTrivial().RTrivial()
Category of j trivial semigroups
For a commutative semigroup, all three axioms are equivalent:
sage: Semigroups().Commutative().LTrivial()
Category of commutative j trivial semigroups
sage: Semigroups().Commutative().RTrivial()
Category of commutative j trivial semigroups
LTrivial()
Return the full subcategory of the $$L$$-trivial objects of self.
Let $$S$$ be (multiplicative) semigroup. The $$L$$-preorder $$\leq_L$$ on $$S$$ is defined by:
$x\leq_L y \qquad \Longleftrightarrow \qquad x \in Sy$
The $$L$$-classes are the equivalence classes for the associated equivalence relation. The semigroup $$S$$ is $$L$$-trivial if all its $$L$$-classes are trivial (that is of cardinality $$1$$), or equivalently if the $$L$$-preorder is in fact a partial order.
EXAMPLES:
sage: C = Semigroups().LTrivial(); C
Category of l trivial semigroups
A $$L$$-trivial semigroup is $$H$$-trivial:
sage: sorted(C.axioms())
['Associative', 'HTrivial', 'LTrivial']
RTrivial()
Return the full subcategory of the $$R$$-trivial objects of self.
Let $$S$$ be (multiplicative) semigroup. The $$R$$-preorder $$\leq_R$$ on $$S$$ is defined by:
$x\leq_R y \qquad \Longleftrightarrow \qquad x \in yS$
The $$R$$-classes are the equivalence classes for the associated equivalence relation. The semigroup $$S$$ is $$R$$-trivial if all its $$R$$-classes are trivial (that is of cardinality $$1$$), or equivalently if the $$R$$-preorder is in fact a partial order.
EXAMPLES:
sage: C = Semigroups().RTrivial(); C
Category of r trivial semigroups
An $$R$$-trivial semigroup is $$H$$-trivial:
sage: sorted(C.axioms())
['Associative', 'HTrivial', 'RTrivial']
class Subquotients(category, *args)
The category of subquotient semi-groups.
EXAMPLES:
sage: Semigroups().Subquotients().all_super_categories()
[Category of subquotients of semigroups,
Category of semigroups,
Category of subquotients of magmas,
Category of magmas,
Category of subquotients of sets,
Category of sets,
Category of sets with partial maps,
Category of objects]
[Category of subquotients of semigroups,
Category of semigroups,
Category of subquotients of magmas,
Category of magmas,
Category of subquotients of sets,
Category of sets,
Category of sets with partial maps,
Category of objects]
example()
Returns an example of subquotient of a semigroup, as per Category.example().
EXAMPLES:
sage: Semigroups().Subquotients().example()
An example of a (sub)quotient semigroup: a quotient of the left zero semigroup
Unital
example(choice='leftzero', **kwds)
Returns an example of a semigroup, as per Category.example().
INPUT:
• choice – str (default: ‘leftzero’). Can be either ‘leftzero’ for the left zero semigroup, or ‘free’ for the free semigroup.
• **kwds – keyword arguments passed onto the constructor for the chosen semigroup.
EXAMPLES:
sage: Semigroups().example(choice='leftzero')
An example of a semigroup: the left zero semigroup
sage: Semigroups().example(choice='free')
An example of a semigroup: the free semigroup generated by ('a', 'b', 'c', 'd')
sage: Semigroups().example(choice='free', alphabet=('a','b'))
An example of a semigroup: the free semigroup generated by ('a', 'b') | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6195895671844482, "perplexity": 7833.905199770501}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570987829458.93/warc/CC-MAIN-20191023043257-20191023070757-00312.warc.gz"} |
https://www.bartleby.com/solution-answer/chapter-122-problem-25e-multivariable-calculus-8th-edition/9781305266643/find-a-unit-vector-that-has-the-same-direction-as-the-given-vector-25-8i-j-4k/9232e257-be71-11e8-9bb5-0ece094302b6 | Chapter 12.2, Problem 25E
### Multivariable Calculus
8th Edition
James Stewart
ISBN: 9781305266643
Chapter
Section
### Multivariable Calculus
8th Edition
James Stewart
ISBN: 9781305266643
Textbook Problem
# Find a unit vector that has the same direction as the given vector.25. 8i − j + 4k
To determine
To find: The unit vector with same direction.
Explanation
Given:
Vector 8ij+4k .
Formula:
Write the expression for magnitude of vector a=a1i+a2j+a3k (|a|) .
|a|=a12+a22++a32 (1)
Write the expression for unit vector with same direction (u) .
u=1|a|a (2)
Substitute 8 for a1 , –1 for a2 , 4 for a3 in equation (1),
|a|=
### Still sussing out bartleby?
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#### Let f be the function defined by f(x) = 2+25x. Find f(4), f(1), f(114), and f(x + 5).
Applied Calculus for the Managerial, Life, and Social Sciences: A Brief Approach
#### In problems 15-26, evaluate each expression. 25.
Mathematical Applications for the Management, Life, and Social Sciences
#### Finding a Unit Vector Find a unit vector in the direction of u=2,3,5
Calculus: Early Transcendental Functions (MindTap Course List)
#### is the binomial series for:
Study Guide for Stewart's Multivariable Calculus, 8th | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8346320986747742, "perplexity": 8098.390232132482}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-47/segments/1573496670135.29/warc/CC-MAIN-20191119093744-20191119121744-00455.warc.gz"} |
https://codereview.stackexchange.com/questions/85364/simple-todo-application/85441 | # Simple todo application
I have been learning HTML/JavaScript and CSS. I have gone through some of the online tutorials, PDFs and books as well. Though, now I am familiar with syntactical stuff, I wasn't sure how I should design or structure code, so I started with a small ToDo application. I didn't want to use any frameworks. As I am still learning, I thought I should spend sometime learning the basics before using any frameworks.
GitHub
{
(function (){
//Create a modal, which contains an array to hold list of todos
var modal = {
init: function () {
this.todolist = [];
this.todolist = JSON.parse(localStorage.getItem("tododata"));
if (this.todolist === null)
this.todolist = [];
},
getTodoList: function () {
return this.todolist;
},
setTodoState: function (intodoid) {
//Set status
this.todolist[intodoid].status === "closed" ?
this.todolist[intodoid].status = "open" : this.todolist[intodoid].status = "closed";
localStorage.setItem("tododata", JSON.stringify(this.todolist));
},
setNewTodo: function (inval) {
this.todolist.push({
id: this.todolist.length,
name: inval,
status: "open"
});
localStorage.setItem("tododata", JSON.stringify(this.todolist));
this.myFirebaseRef.push({id: this.todolist.length, name: inval, status: "open"});
},
clearall: function () {
this.todolist = [];
}
}
//Create a View, which interacts with Controller and alters the display in HTML
var view = {
init: function () {
this.todolst = $('#todolistelm'); this.todolst.html(' '); view.render();$('#clearall').click(function () {
localStorage.clear();
controller.clearall();
view.render();
});
},
render: function () {
var htmlStr = '';
var clr = true;
var todoelem = $('#todolistelm'); todoelem.html(''); if (controller.getTodoList().length === 0) {$("#cleanmsg").css("visibility", "visible");
$("#displaysection").css("visibility", "hidden") } else {$("#cleanmsg").css("visibility", "hidden");
$("#displaysection").css("visibility", "visible") } controller.getTodoList().forEach(function (todo) { //DOM elements var elemId = ' '; var lielem =$('<li></li>');
var spanelem = $('<span></span>'); var taskid = "#task" + todo.id; //Create <li> element and add required classes lielem.addClass("list-group-item"); //Set status of the todo item todo.status === "closed" ? lielem.addClass("completed") : lielem.addClass(""); //Set alternate color clr === true ? lielem.addClass("colored") : lielem.addClass(""); clr = !clr; //Create <span> and add required classes and IDs spanelem.addClass("glyphicon"); spanelem.addClass("glyphicon-ok pull-right"); spanelem.addClass("todocomplete"); spanelem.attr('id', "task" + todo.id); //Append span and name to <li> lielem.append(spanelem); lielem.append(todo.name); //Append <li> to main list$(todoelem).append(lielem);
$(taskid).click(function (todoid) { return function () { controller.setTodoState(todoid); view.render(); }; }(todo.id)); }); //Set focus on input textbox by default$('#intodo').focus();
}
};
//Create a controller, which acts as a mediator between View and Modal
var controller = {
init: function () {
//Initialize view and modal
modal.init();
view.init();
},
getTodoList: function () {
return modal.getTodoList();
},
setTodoState: function (intodoid) {
modal.setTodoState(intodoid);
},
setNewTodo: function (inval) {
modal.setNewTodo(inval);
},
clearall: function () {
modal.clearall();
}
};
//Set ENTER key on the input text box
$('#intodo').keypress(function (e) { if (((e.which && e.which == 13) || (e.keyCode && e.KeyCode == 13)) &&$("#intodo").val().trim().length > 0) {
controller.setNewTodo($("#intodo").val()); view.render();$("#intodo").val('');
}
});
//Set the controller to start the work
controller.init();
})();
}
Can someone go through this code and let me know if this follows the best practices or not, as well as any areas that I should probably be focusing on?
From a quick once over:
• Your first line creates an anonymous function, it offers you the opportunity to pick a great function name that conveys to the reader what he is about to be exposed to like (function todoApp(){
• This
init: function () {
this.todolist = [];
this.todolist = JSON.parse(localStorage.getItem("tododata"));
if (this.todolist === null)
this.todolist = [];
},
could be
init: function () {
this.todolist = JSON.parse(localStorage.getItem("tododata")) || [];
}
essentially you were overwriting this.todolist = [] with
this.todolist = JSON.parse(localStorage.getItem("tododata"));
furthermore you should never drop the curly braces after an if block
• You are copy pasting this line of code all over the place, you should have a dedicated function for this:
localStorage.setItem("tododata", JSON.stringify(this.todolist));
• This:
setTodoState: function (intodoid) {
//Set status
this.todolist[intodoid].status === "closed" ?
this.todolist[intodoid].status = "open" : this.todolist[intodoid].status = "closed";
localStorage.setItem("tododata", JSON.stringify(this.todolist));
},
has a few problems, intodoid is an unfortunate name because it is not lowerCamelCase and because it smells like Hungarian notation. Also the repetition of this.todolist[intodoid].status is too much. I would suggest something like this:
toggleTodoState: function (todoId) {
//Toggle status
var status = this.todolist[todoId].status;
this.todolist[todoId].status = status == "closed" ? "open" : "closed";
updateTodoData();
}, | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.21721339225769043, "perplexity": 11096.9216551765}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-30/segments/1563195525863.49/warc/CC-MAIN-20190718231656-20190719013656-00402.warc.gz"} |
https://www.science.gov/topicpages/p/parameterized+scatter+removal.html | Sample records for parameterized scatter removal
1. THE DEVELOPMENT OF A PARAMETERIZED SCATTER REMOVAL ALGORITHM FOR NUCLEAR MATERIALS IDENTIFICATION SYSTEM IMAGING
SciTech Connect
Grogan, Brandon R
2010-05-01
This report presents a novel method for removing scattering effects from Nuclear Materials Identification System (NMIS) imaging. The NMIS uses fast neutron radiography to generate images of the internal structure of objects nonintrusively. If the correct attenuation through the object is measured, the positions and macroscopic cross sections of features inside the object can be determined. The cross sections can then be used to identify the materials, and a 3D map of the interior of the object can be reconstructed. Unfortunately, the measured attenuation values are always too low because scattered neutrons contribute to the unattenuated neutron signal. Previous efforts to remove the scatter from NMIS imaging have focused on minimizing the fraction of scattered neutrons that are misidentified as directly transmitted by electronically collimating and time tagging the source neutrons. The parameterized scatter removal algorithm (PSRA) approaches the problem from an entirely new direction by using Monte Carlo simulations to estimate the point scatter functions (PScFs) produced by neutrons scattering in the object. PScFs have been used to remove scattering successfully in other applications, but only with simple 2D detector models. This work represents the first time PScFs have ever been applied to an imaging detector geometry as complicated as the NMIS. By fitting the PScFs using a Gaussian function, they can be parameterized, and the proper scatter for a given problem can be removed without the need for rerunning the simulations each time. In order to model the PScFs, an entirely new method for simulating NMIS measurements was developed for this work. The development of the new models and the codes required to simulate them are presented in detail. The PSRA was used on several simulated and experimental measurements, and chi-squared goodness of fit tests were used to compare the corrected values to the ideal values that would be expected with no scattering. Using the
2. The Development of a Parameterized Scatter Removal Algorithm for Nuclear Materials Identification System Imaging
SciTech Connect
Grogan, Brandon Robert
2010-03-01
This dissertation presents a novel method for removing scattering effects from Nuclear Materials Identification System (NMIS) imaging. The NMIS uses fast neutron radiography to generate images of the internal structure of objects non-intrusively. If the correct attenuation through the object is measured, the positions and macroscopic cross-sections of features inside the object can be determined. The cross sections can then be used to identify the materials and a 3D map of the interior of the object can be reconstructed. Unfortunately, the measured attenuation values are always too low because scattered neutrons contribute to the unattenuated neutron signal. Previous efforts to remove the scatter from NMIS imaging have focused on minimizing the fraction of scattered neutrons which are misidentified as directly transmitted by electronically collimating and time tagging the source neutrons. The parameterized scatter removal algorithm (PSRA) approaches the problem from an entirely new direction by using Monte Carlo simulations to estimate the point scatter functions (PScFs) produced by neutrons scattering in the object. PScFs have been used to remove scattering successfully in other applications, but only with simple 2D detector models. This work represents the first time PScFs have ever been applied to an imaging detector geometry as complicated as the NMIS. By fitting the PScFs using a Gaussian function, they can be parameterized and the proper scatter for a given problem can be removed without the need for rerunning the simulations each time. In order to model the PScFs, an entirely new method for simulating NMIS measurements was developed for this work. The development of the new models and the codes required to simulate them are presented in detail. The PSRA was used on several simulated and experimental measurements and chi-squared goodness of fit tests were used to compare the corrected values to the ideal values that would be expected with no scattering. Using
3. Comment on S-matrix parameterizations in NN-scattering
SciTech Connect
Mulders, P. J.
1981-08-01
The parameterization of the S-matrix used for the elastic part of the NN-scattering matrix in, for example, the Virginia Polytechnic Institute ineractive nucleon-nucleon program SAID, is not general enough to parameterize any 2 by 2 submatrix of a unitary matrix.
4. On the radiative properties of ice clouds: Light scattering, remote sensing, and radiation parameterization
Yang, Ping; Liou, Kuo-Nan; Bi, Lei; Liu, Chao; Yi, Bingqi; Baum, Bryan A.
2015-01-01
Presented is a review of the radiative properties of ice clouds from three perspectives: light scattering simulations, remote sensing applications, and broadband radiation parameterizations appropriate for numerical models. On the subject of light scattering simulations, several classical computational approaches are reviewed, including the conventional geometric-optics method and its improved forms, the finite-difference time domain technique, the pseudo-spectral time domain technique, the discrete dipole approximation method, and the T-matrix method, with specific applications to the computation of the single-scattering properties of individual ice crystals. The strengths and weaknesses associated with each approach are discussed. With reference to remote sensing, operational retrieval algorithms are reviewed for retrieving cloud optical depth and effective particle size based on solar or thermal infrared (IR) bands. To illustrate the performance of the current solar- and IR-based retrievals, two case studies are presented based on spaceborne observations. The need for a more realistic ice cloud optical model to obtain spectrally consistent retrievals is demonstrated. Furthermore, to complement ice cloud property studies based on passive radiometric measurements, the advantage of incorporating lidar and/or polarimetric measurements is discussed. The performance of ice cloud models based on the use of different ice habits to represent ice particles is illustrated by comparing model results with satellite observations. A summary is provided of a number of parameterization schemes for ice cloud radiative properties that were developed for application to broadband radiative transfer submodels within general circulation models (GCMs). The availability of the single-scattering properties of complex ice habits has led to more accurate radiation parameterizations. In conclusion, the importance of using nonspherical ice particle models in GCM simulations for climate
5. Evaluating model parameterizations of submicron aerosol scattering and absorption with in situ data from ARCTAS 2008
Alvarado, Matthew J.; Lonsdale, Chantelle R.; Macintyre, Helen L.; Bian, Huisheng; Chin, Mian; Ridley, David A.; Heald, Colette L.; Thornhill, Kenneth L.; Anderson, Bruce E.; Cubison, Michael J.; Jimenez, Jose L.; Kondo, Yutaka; Sahu, Lokesh K.; Dibb, Jack E.; Wang, Chien
2016-07-01
Accurate modeling of the scattering and absorption of ultraviolet and visible radiation by aerosols is essential for accurate simulations of atmospheric chemistry and climate. Closure studies using in situ measurements of aerosol scattering and absorption can be used to evaluate and improve models of aerosol optical properties without interference from model errors in aerosol emissions, transport, chemistry, or deposition rates. Here we evaluate the ability of four externally mixed, fixed size distribution parameterizations used in global models to simulate submicron aerosol scattering and absorption at three wavelengths using in situ data gathered during the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. The four models are the NASA Global Modeling Initiative (GMI) Combo model, GEOS-Chem v9-02, the baseline configuration of a version of GEOS-Chem with online radiative transfer calculations (called GC-RT), and the Optical Properties of Aerosol and Clouds (OPAC v3.1) package. We also use the ARCTAS data to perform the first evaluation of the ability of the Aerosol Simulation Program (ASP v2.1) to simulate submicron aerosol scattering and absorption when in situ data on the aerosol size distribution are used, and examine the impact of different mixing rules for black carbon (BC) on the results. We find that the GMI model tends to overestimate submicron scattering and absorption at shorter wavelengths by 10-23 %, and that GMI has smaller absolute mean biases for submicron absorption than OPAC v3.1, GEOS-Chem v9-02, or GC-RT. However, the changes to the density and refractive index of BC in GC-RT improve the simulation of submicron aerosol absorption at all wavelengths relative to GEOS-Chem v9-02. Adding a variable size distribution, as in ASP v2.1, improves model performance for scattering but not for absorption, likely due to the assumption in ASP v2.1 that BC is present at a constant mass fraction
6. Parameterization of structures in HE composites using surrogate materials: A small angle neutron scattering investigation
SciTech Connect
Mang, J.T.; Hjelm, R.P.; Skidmore, C.B.; Howe, P.M.
1996-07-01
High explosive materials used in the nuclear stockpile are composites of crystalline high explosives (HE) with binder materials, such as Estane. In such materials, there are naturally occurring density fluctuations (defects) due to cracks, internal (in the HE) and external (in the binder) voids and other artifacts of preparation. Changes in such defects due to material aging can affect the response of explosives due to shock, impact and thermal loading. Modeling efforts are attempting to provide quantitative descriptions of explosive response from the lowest ignition thresholds to the development of full blown detonations and explosions, however, adequate descriptions of these processes require accurate measurements of a number of structural parameters of the HE composite. Since different defects are believed to affect explosive sensitivity in different ways it is necessary to quantitatively differentiate between defect types. The authors report here preliminary results of SANS measurements on surrogates for HE materials. The objective of these measurements was to develop methodologies using SANS techniques to parameterize internal void size distributions in a surrogate material, sugar, to simulate an HE used in the stockpile, HMX. Sugar is a natural choice as a surrogate material, as it has the same crystal structure, has similar intragranular voids and has similar mechanical properties as HMX. It is used extensively as a mock material for explosives. Samples were used with two void size distributions: one with a sufficiently small mean particle size that only small occluded voids are present in significant concentrations, and one where the void sizes could be larger. By using methods in small-angle neutron scattering, they were able to isolate the scattering arising from particle-liquid interfaces and internal voids.
7. Laser scattering measurement for laser removal of graffiti
Tearasongsawat, Watcharawee; Kittiboonanan, Phumipat; Luengviriya, Chaiya; Ratanavis, Amarin
2015-07-01
In this contribution, a technical development of the laser scattering measurement for laser removal of graffiti is reported. This study concentrates on the removal of graffiti from metal surfaces. Four colored graffiti paints were applied to stainless steel samples. Cleaning efficiency was evaluated by the laser scattering system. In this study, an angular laser removal of graffiti was attempted to examine the removal process under practical conditions. A Q-switched Nd:YAG laser operating at 1.06 microns with the repetition rate of 1 Hz was used to remove graffiti from stainless steel samples. The laser fluence was investigated from 0.1 J/cm2 to 7 J/cm2. The laser parameters to achieve the removal effectiveness were determined by using the laser scattering system. This study strongly leads to further development of the potential online surface inspection for the removal of graffiti.
8. Parameterization of single-scattering albedo (SSA) and absorption Ångström exponent (AAE) with EC / OC for aerosol emissions from biomass burning
Pokhrel, Rudra P.; Wagner, Nick L.; Langridge, Justin M.; Lack, Daniel A.; Jayarathne, Thilina; Stone, Elizabeth A.; Stockwell, Chelsea E.; Yokelson, Robert J.; Murphy, Shane M.
2016-08-01
Single-scattering albedo (SSA) and absorption Ångström exponent (AAE) are two critical parameters in determining the impact of absorbing aerosol on the Earth's radiative balance. Aerosol emitted by biomass burning represent a significant fraction of absorbing aerosol globally, but it remains difficult to accurately predict SSA and AAE for biomass burning aerosol. Black carbon (BC), brown carbon (BrC), and non-absorbing coatings all make substantial contributions to the absorption coefficient of biomass burning aerosol. SSA and AAE cannot be directly predicted based on fuel type because they depend strongly on burn conditions. It has been suggested that SSA can be effectively parameterized via the modified combustion efficiency (MCE) of a biomass burning event and that this would be useful because emission factors for CO and CO2, from which MCE can be calculated, are available for a large number of fuels. Here we demonstrate, with data from the FLAME-4 experiment, that for a wide variety of globally relevant biomass fuels, over a range of combustion conditions, parameterizations of SSA and AAE based on the elemental carbon (EC) to organic carbon (OC) mass ratio are quantitatively superior to parameterizations based on MCE. We show that the EC / OC ratio and the ratio of EC / (EC + OC) both have significantly better correlations with SSA than MCE. Furthermore, the relationship of EC / (EC + OC) with SSA is linear. These improved parameterizations are significant because, similar to MCE, emission factors for EC (or black carbon) and OC are available for a wide range of biomass fuels. Fitting SSA with MCE yields correlation coefficients (Pearson's r) of ˜ 0.65 at the visible wavelengths of 405, 532, and 660 nm while fitting SSA with EC / OC or EC / (EC + OC) yields a Pearson's r of 0.94-0.97 at these same wavelengths. The strong correlation coefficient at 405 nm (r = 0.97) suggests that parameterizations based on EC / OC or EC / (EC + OC) have good predictive
9. Measurement and parameterization of wave attenuation and scattering in the Marginal Ice Zone using Sentinel-1 SAR data
Collard, F.; Ardhuin, F.; Guitton, G.; Dumont, D.; Nicot, P.; Accenti, M.; Girard-Ardhuin, F.
2014-12-01
Sentinel-1A launched by the European Space Agency in April 2014 will complete its full calibration and validation phase including Level2 products early in 2015 but image quality is already good enought for scientific exploitation of observed wave modulations. The larger frequency bandwidth and new acquisition modes are providing a much improved capability for imaging ocean waves in the open water and in the ice compared to Envisat. Here we estimate wave spectra in the Arctic assuming a spatially uniform modulation transfer function where the backscatter over ice is homogeneous, matching the wave heights in open ocean and ice at the ice edge. These wave properties are used to estimate attenuation scales for wavelength longer than twice the radar image resolution. These estimated attenuations are compared to model results based on WAVEWATCH III, where attenuation and scattering uses a combination of friction below the ice and scattering adapted from Dumont et al. (2011) and Williams et al. (2013).
10. Seed removal by scatter-hoarding rodents: the effects of tannin and nutrient concentration.
PubMed
Wang, Bo; Yang, Xiaolan
2015-04-01
The mutualistic interaction between scatter-hoarding rodents and seed plants have a long co-evolutionary history. Plants are believed to have evolved traits that influence the foraging behavior of rodents, thus increasing the probability of seed removal and caching, which benefits the establishment of seedlings. Tannin and nutrient content in seeds are considered among the most essential factors in this plant-animal interaction. However, most previous studies used different species of plant seeds, rendering it difficult to tease apart the relative effect of each single nutrient on rodent foraging behavior due to confounding combinations of nutrient contents across seed species. Hence, to further explore how tannin and different nutritional traits of seed affect scatter-hoarding rodent foraging preferences, we manipulated tannin, fat, protein and starch content levels, and also seed size levels by using an artificial seed system. Our results showed that both tannin and various nutrients significantly affected rodent foraging preferences, but were also strongly affected by seed size. In general, rodents preferred to remove seeds with less tannin. Fat addition could counteract the negative effect of tannin on seed removal by rodents, while the effect of protein addition was weaker. Starch by itself had no effect, but it interacted with tannin in a complex way. Our findings shed light on the effects of tannin and nutrient content on seed removal by scatter-hoarding rodents. We therefore, believe that these and perhaps other seed traits should interactively influence this important plant-rodent interaction. However, how selection operates on seed traits to counterbalance these competing interests/factors merits further study.
11. Seed removal by scatter-hoarding rodents: the effects of tannin and nutrient concentration.
PubMed
Wang, Bo; Yang, Xiaolan
2015-04-01
The mutualistic interaction between scatter-hoarding rodents and seed plants have a long co-evolutionary history. Plants are believed to have evolved traits that influence the foraging behavior of rodents, thus increasing the probability of seed removal and caching, which benefits the establishment of seedlings. Tannin and nutrient content in seeds are considered among the most essential factors in this plant-animal interaction. However, most previous studies used different species of plant seeds, rendering it difficult to tease apart the relative effect of each single nutrient on rodent foraging behavior due to confounding combinations of nutrient contents across seed species. Hence, to further explore how tannin and different nutritional traits of seed affect scatter-hoarding rodent foraging preferences, we manipulated tannin, fat, protein and starch content levels, and also seed size levels by using an artificial seed system. Our results showed that both tannin and various nutrients significantly affected rodent foraging preferences, but were also strongly affected by seed size. In general, rodents preferred to remove seeds with less tannin. Fat addition could counteract the negative effect of tannin on seed removal by rodents, while the effect of protein addition was weaker. Starch by itself had no effect, but it interacted with tannin in a complex way. Our findings shed light on the effects of tannin and nutrient content on seed removal by scatter-hoarding rodents. We therefore, believe that these and perhaps other seed traits should interactively influence this important plant-rodent interaction. However, how selection operates on seed traits to counterbalance these competing interests/factors merits further study. PMID:25625425
12. On the correct estimation of gap fraction: how to remove scattering effects in the gap fraction measurements?
Ryu, Y.; Kobayashi, H.; Welles, J.; Norman, J.
2011-12-01
Correct estimation of gap fraction is essential to quantify canopy architectural variables such as leaf area index and clumping index, which mainly control land-atmosphere interactions. However, gap fraction measurements from optical sensors are contaminated by scattered radiation by canopy and ground surface. In this study, we propose a simple invertible bidirectional transmission model to remove scattering effects from gap fraction measurements. The model shows that 1) scattering factor appears highest where leaf area index is 1-2 in non-clumped canopy, 2) relative scattering factor (scattering factor/measured gap fraction) increases with leaf area index, 3) bright land surface (e.g. snow and bright soil) can contribute a significant scattering factor, 4) the scattering factor is not marginal even in highly diffused sky condition. By incorporating the model with LAI2200 data collected in an open savanna ecosystem, we find that the scattering factor causes significant underestimation of leaf area index (25%) and significant overestimation of clumping index (6 %). The results highlight that some LAI-2000-based LAI estimates from around the world may be underestimated, particularly in highly clumped broad-leaf canopies. Fortunately, the importance of scattering could be assessed with software from LICOR, Inc., which will incorporate the scattering model from this study in a post processing mode after data has been collected by a LAI-2000 or LAI-2200.
13. Parameterizing the Raindrop Size Distribution
NASA Technical Reports Server (NTRS)
1996-01-01
This paper addresses the problem of finding a parametric form for the raindrop size distribution (DSD) that(1) is an appropriate model for tropical rainfall, and (2) involves statistically independent parameters. Such a parameterization is derived in this paper. One of the resulting three "canonical" parameters turns out to vary relatively little, thus making the parameterization particularly useful for remote sensing applications. In fact, a new set of r drop-size-distribution-based Z-R and k-R relations is obtained. Only slightly more complex than power laws, they are very good approximations to the exact radar relations one would obtain using Mie scattering. The coefficients of the new relations are directly related to the shape parameters of the particular DSD that one starts with. Perhaps most important, since the coefficients are independent of the rain rate itself, the relations are ideally suited for rain retrieval algorithms.
14. Radiation properties and emissivity parameterization of high level thin clouds
NASA Technical Reports Server (NTRS)
Wu, M.-L. C.
1984-01-01
To parameterize emissivity of clouds at 11 microns, a study has been made in an effort to understand the radiation field of thin clouds. The contributions to the intensity and flux from different sources and through different physical processes are calculated by using the method of successive orders of scattering. The effective emissivity of thin clouds is decomposed into the effective absorption emissivity, effective scattering emissivity, and effective reflection emissivity. The effective absorption emissivity depends on the absorption and emission of the cloud; it is parameterized in terms of optical thickness. The effective scattering emissivity depends on the scattering properties of the cloud; it is parameterized in terms of optical thickness and single scattering albedo. The effective reflection emissivity follows the similarity relation as in the near infrared cases. This is parameterized in terms of the similarity parameter and optical thickness, as well as the temperature difference between the cloud and ground.
15. Scatter estimation and removal of anti-scatter grid-line artifacts from anthropomorphic head phantom images taken with a high resolution image detector
Rana, R.; Jain, A.; Shankar, A.; Bednarek, D. R.; Rudin, S.
2016-03-01
In radiography, one of the best methods to eliminate image-degrading scatter radiation is the use of anti-scatter grids. However, with high-resolution dynamic imaging detectors, stationary anti-scatter grids can leave grid-line shadows and moiré patterns on the image, depending upon the line density of the grid and the sampling frequency of the x-ray detector. Such artifacts degrade the image quality and may mask small but important details such as small vessels and interventional device features. Appearance of these artifacts becomes increasingly severe as the detector spatial resolution is improved. We have previously demonstrated that, to remove these artifacts by dividing out a reference grid image, one must first subtract the residual scatter that penetrates the grid; however, for objects with anatomic structure, scatter varies throughout the FOV and a spatially differing amount of scatter must be subtracted. In this study, a standard stationary Smit-Rontgen X-ray grid (line density - 70 lines/cm, grid ratio - 13:1) was used with a high-resolution CMOS detector, the Dexela 1207 (pixel size - 75 micron) to image anthropomorphic head phantoms. For a 15 x 15cm FOV, scatter profiles of the anthropomorphic head phantoms were estimated then iteratively modified to minimize the structured noise due to the varying grid-line artifacts across the FOV. Images of the anthropomorphic head phantoms taken with the grid, before and after the corrections, were compared demonstrating almost total elimination of the artifact over the full FOV. Hence, with proper computational tools, antiscatter grid artifacts can be corrected, even during dynamic sequences.
16. Solution scattering and FRET studies on nucleosomes reveal DNA unwrapping effects of H3 and H4 tail removal.
PubMed
Andresen, Kurt; Jimenez-Useche, Isabel; Howell, Steven C; Yuan, Chongli; Qiu, Xiangyun
2013-01-01
Using a combination of small-angle X-ray scattering (SAXS) and fluorescence resonance energy transfer (FRET) measurements we have determined the role of the H3 and H4 histone tails, independently, in stabilizing the nucleosome DNA terminal ends from unwrapping from the nucleosome core. We have performed solution scattering experiments on recombinant wild-type, H3 and H4 tail-removed mutants and fit all scattering data with predictions from PDB models and compared these experiments to complementary DNA-end FRET experiments. Based on these combined SAXS and FRET studies, we find that while all nucleosomes exhibited DNA unwrapping, the extent of this unwrapping is increased for nucleosomes with the H3 tails removed but, surprisingly, decreased in nucleosomes with the H4 tails removed. Studies of salt concentration effects show a minimum amount of DNA unwrapping for all complexes around 50-100mM of monovalent ions. These data exhibit opposite roles for the positively-charged nucleosome tails, with the ability to decrease access (in the case of the H3 histone) or increase access (in the case of the H4 histone) to the DNA surrounding the nucleosome. In the range of salt concentrations studied (0-200mM KCl), the data point to the H4 tail-removed mutant at physiological (50-100mM) monovalent salt concentration as the mononucleosome with the least amount of DNA unwrapping. PMID:24265699
17. Solution Scattering and FRET Studies on Nucleosomes Reveal DNA Unwrapping Effects of H3 and H4 Tail Removal
PubMed Central
Andresen, Kurt; Jimenez-Useche, Isabel; Howell, Steven C.; Yuan, Chongli; Qiu, Xiangyun
2013-01-01
Using a combination of small-angle X-ray scattering (SAXS) and fluorescence resonance energy transfer (FRET) measurements we have determined the role of the H3 and H4 histone tails, independently, in stabilizing the nucleosome DNA terminal ends from unwrapping from the nucleosome core. We have performed solution scattering experiments on recombinant wild-type, H3 and H4 tail-removed mutants and fit all scattering data with predictions from PDB models and compared these experiments to complementary DNA-end FRET experiments. Based on these combined SAXS and FRET studies, we find that while all nucleosomes exhibited DNA unwrapping, the extent of this unwrapping is increased for nucleosomes with the H3 tails removed but, surprisingly, decreased in nucleosomes with the H4 tails removed. Studies of salt concentration effects show a minimum amount of DNA unwrapping for all complexes around 50-100mM of monovalent ions. These data exhibit opposite roles for the positively-charged nucleosome tails, with the ability to decrease access (in the case of the H3 histone) or increase access (in the case of the H4 histone) to the DNA surrounding the nucleosome. In the range of salt concentrations studied (0-200mM KCl), the data point to the H4 tail-removed mutant at physiological (50-100mM) monovalent salt concentration as the mononucleosome with the least amount of DNA unwrapping. PMID:24265699
18. The Influence of Microphysical Cloud Parameterization on Microwave Brightness Temperatures
NASA Technical Reports Server (NTRS)
Skofronick-Jackson, Gail M.; Gasiewski, Albin J.; Wang, James R.; Zukor, Dorothy J. (Technical Monitor)
2000-01-01
The microphysical parameterization of clouds and rain-cells plays a central role in atmospheric forward radiative transfer models used in calculating passive microwave brightness temperatures. The absorption and scattering properties of a hydrometeor-laden atmosphere are governed by particle phase, size distribution, aggregate density., shape, and dielectric constant. This study identifies the sensitivity of brightness temperatures with respect to the microphysical cloud parameterization. Cloud parameterizations for wideband (6-410 GHz observations of baseline brightness temperatures were studied for four evolutionary stages of an oceanic convective storm using a five-phase hydrometeor model in a planar-stratified scattering-based radiative transfer model. Five other microphysical cloud parameterizations were compared to the baseline calculations to evaluate brightness temperature sensitivity to gross changes in the hydrometeor size distributions and the ice-air-water ratios in the frozen or partly frozen phase. The comparison shows that, enlarging the rain drop size or adding water to the partly Frozen hydrometeor mix warms brightness temperatures by up to .55 K at 6 GHz. The cooling signature caused by ice scattering intensifies with increasing ice concentrations and at higher frequencies. An additional comparison to measured Convection and Moisture LA Experiment (CAMEX 3) brightness temperatures shows that in general all but, two parameterizations produce calculated T(sub B)'s that fall within the observed clear-air minima and maxima. The exceptions are for parameterizations that, enhance the scattering characteristics of frozen hydrometeors.
19. Stochastic Convection Parameterizations
NASA Technical Reports Server (NTRS)
Teixeira, Joao; Reynolds, Carolyn; Suselj, Kay; Matheou, Georgios
2012-01-01
computational fluid dynamics, radiation, clouds, turbulence, convection, gravity waves, surface interaction, radiation interaction, cloud and aerosol microphysics, complexity (vegetation, biogeochemistry, radiation versus turbulence/convection stochastic approach, non-linearities, Monte Carlo, high resolutions, large-Eddy Simulations, cloud structure, plumes, saturation in tropics, forecasting, parameterizations, stochastic, radiation-clod interaction, hurricane forecasts
20. Removal of scattering centers in CBO crystals by the vapor transport equilibration process
Rajesh, D.; Eiro, T.; Yoshimura, M.; Mori, Y.; Jayavel, R.; Sasaki, T.
2008-04-01
Large-size cesium triborate (CsB 3O 5:CBO) crystals were grown from self-flux solutions by top-seeded solution growth. The crystals have numerous scattering centers that were found to depend on the temperature from which the crystals were grown. The weight loss measurements revealed that more weight loss occurred at the growth temperature of 74 mol% B 2O 3. During the cooling process (after growth) there is a possibility of the crystal being shifted to the off-stoichiometric composition because of cesium out-diffusion. To bring the crystals to near stoichiometric solutions, the vapor transport equilibration (VTE) process (post-growth heat treatment) was carried out and the scattering centers were reduced. The cesium atmosphere used in VTE processing was very important for the diffusion of cesium into the crystal and to bring the crystals to near stoichiometric composition.
1. Parameterization of longwave optical properties for water clouds
Wang, H. Q.; Zhao, G. X.
2002-02-01
Based on relationships between cloud microphysical and optical properties, three different parameterization schemes for narrow and broad band optical properties in longwave region for water clouds have been presented. The effects of different parameterization schemes and different number of broad bands used on cloud radiative properties have been investigated. The effect of scattering role of cloud drops on longwave radiation fluxes and cooling rates in cloudy atmospheres has also been analyzed.
2. Optimization of parameterized lightpipes
Koshel, R. John
2007-01-01
Parameterization via the bend locus curve allows optimization of single-spherical-bend lightpipes. It takes into account the bend radii, the bend ratio, allowable volume, thickness, and other terms. Parameterization of the lightpipe allows the inclusion of a constrained optimizer to maximize performance of the lightpipe. The simplex method is used for optimization. The standard and optimal simplex methods are used to maximize the standard Lambertian transmission of the lightpipe. A second case presents analogous results when the ray-sample weighted, peak-to-average irradiance uniformity is included with the static Lambertian transmission. These results are compared to a study of the constrained merit space. Results show that both optimizers can locate the optimal solution, but the optimal simplex method accomplishes such with a reduced number of ray-trace evaluations.
3. Parameterizing the Deceleration Parameter
Pavón, D.; Duran, I.; Del Campo, S.; Herrera, R.
2015-01-01
We propose and constrain with the latest observational data three parameterizations of the deceleration parameter, valid from the matter era to the far future. They are well behaved and do not diverge at any redshift. On the other hand, they are model independent in the sense that in constructing them the only assumption made was that the Universe is homogeneous and isotropic at large scales.
4. SU-E-I-49: Simulation Study for Removing Scatter Radiation in Cesium-Iodine Based Flat Panel Detector System
SciTech Connect
Yoon, Y; Park, M; Kim, H; Kim, K; Kim, J; Morishita, J
2015-06-15
5. Determinants of seed removal distance by scatter-hoarding rodents in deciduous forests.
PubMed
Moore, Jeffrey E; McEuen, Amy B; Swihart, Robert K; Contreras, Thomas A; Steele, Michael A
2007-10-01
Scatter-hoarding rodents should space food caches to maximize cache recovery rate (to minimize loss to pilferers) relative to the energetic cost of carrying food items greater distances. Optimization models of cache spacing make two predictions. First, spacing of caches should be greater for food items with greater energy content. Second, the mean distance between caches should increase with food abundance. However, the latter prediction fails to account for the effect of food abundance on the behavior of potential pilferers or on the ability of caching individuals to acquire food by means other than recovering their own caches. When considering these factors, shorter cache distances may be predicted in conditions of higher food abundance. We predicted that seed caching distances would be greater for food items of higher energy content and during lower ambient food abundance and that the effect of seed type on cache distance variation would be lower during higher food abundance. We recorded distances moved for 8636 seeds of five seed types at 15 locations in three forested sites in Pennsylvania, USA, and 29 forest fragments in Indiana, U.S.A., across five different years. Seed production was poor in three years and high in two years. Consistent with previous studies, seeds with greater energy content were moved farther than less profitable food items. Seeds were dispersed less far in seed-rich years than in seed-poor years, contrary to predictions of conventional models. Interactions were important, with seed type effects more evident in seed-poor years. These results suggest that, when food is superabundant, optimal cache distances are more strongly determined by minimizing energy cost of caching than by minimizing pilfering rates and that cache loss rates may be more strongly density-dependent in times of low seed abundance.
6. Parameterization of the scavenging coefficient for particle scavenging by drops
Fredericks, Steven; Saylor, J. R.
2014-11-01
The removal of particles by drops occurs in many environmentally relevant scenarios such as particle fallout from rain, as well as in many industrial applications such as sprays for dust control in mines. In applications like these the ability of a drop to scavenge a particle is quantified by the scavenging coefficient, E, which is the fraction of particles removed. Though the physics controlling particle scavenging by drops suggests that E is controlled by several dimensionless groups, E is typically correlated to just the Stokes number. A survey of published experimental data shows significant scatter in plots of E versus the Stokes number, occasionally exceeding three orders of magnitude. There is also a large discrepancy between the published theories for E. A parameterization study was conducted to ascertain if and how inclusion of other dimensionless groups could better collapse the extant data for E and the results of that study are presented in this talk. Brief mention will also be made of recent experiments by the authors where E was measured for a liquid drop suspended in an ultrasonic standing wave field, where the drop diameter and gas velocity can be independently varied unlike the more typical experiments where these quantities are coupled.
7. [Characteristics and Parameterization for Atmospheric Extinction Coefficient in Beijing].
PubMed
Chen, Yi-na; Zhao, Pu-sheng; He, Di; Dong, Fan; Zhao, Xiu-juan; Zhang, Xiao-ling
2015-10-01
In order to study the characteristics of atmospheric extinction coefficient in Beijing, systematic measurements had been carried out for atmospheric visibility, PM2.5 concentration, scattering coefficient, black carbon, reactive gases, and meteorological parameters from 2013 to 2014. Based on these data, we compared some published fitting schemes of aerosol light scattering enhancement factor [ f(RH)], and discussed the characteristics and the key influence factors for atmospheric extinction coefficient. Then a set of parameterization models of atmospheric extinction coefficient for different seasons and different polluted levels had been established. The results showed that aerosol scattering accounted for more than 94% of total light extinction. In the summer and autumn, the aerosol hygroscopic growth caused by high relative humidity had increased the aerosol scattering coefficient by 70 to 80 percent. The parameterization models could reflect the influencing mechanism of aerosol and relative humidity upon ambient light extinction, and describe the seasonal variations of aerosol light extinction ability. PMID:26841588
8. [Characteristics and Parameterization for Atmospheric Extinction Coefficient in Beijing].
PubMed
Chen, Yi-na; Zhao, Pu-sheng; He, Di; Dong, Fan; Zhao, Xiu-juan; Zhang, Xiao-ling
2015-10-01
In order to study the characteristics of atmospheric extinction coefficient in Beijing, systematic measurements had been carried out for atmospheric visibility, PM2.5 concentration, scattering coefficient, black carbon, reactive gases, and meteorological parameters from 2013 to 2014. Based on these data, we compared some published fitting schemes of aerosol light scattering enhancement factor [ f(RH)], and discussed the characteristics and the key influence factors for atmospheric extinction coefficient. Then a set of parameterization models of atmospheric extinction coefficient for different seasons and different polluted levels had been established. The results showed that aerosol scattering accounted for more than 94% of total light extinction. In the summer and autumn, the aerosol hygroscopic growth caused by high relative humidity had increased the aerosol scattering coefficient by 70 to 80 percent. The parameterization models could reflect the influencing mechanism of aerosol and relative humidity upon ambient light extinction, and describe the seasonal variations of aerosol light extinction ability.
9. Parameterization of solar cells
Appelbaum, J.; Chait, A.; Thompson, D.
1992-10-01
The aggregation (sorting) of the individual solar cells into an array is commonly based on a single operating point on the current-voltage (I-V) characteristic curve. An alternative approach for cell performance prediction and cell screening is provided by modeling the cell using an equivalent electrical circuit, in which the parameters involved are related to the physical phenomena in the device. These analytical models may be represented by a double exponential I-V characteristic with seven parameters, by a double exponential model with five parameters, or by a single exponential equation with four or five parameters. In this article we address issues concerning methodologies for the determination of solar cell parameters based on measured data points of the I-V characteristic, and introduce a procedure for screening of solar cells for arrays. We show that common curve fitting techniques, e.g., least squares, may produce many combinations of parameter values while maintaining a good fit between the fitted and measured I-V characteristics of the cell. Therefore, techniques relying on curve fitting criteria alone cannot be directly used for cell parameterization. We propose a consistent procedure which takes into account the entire set of parameter values for a batch of cells. This procedure is based on a definition of a mean cell representing the batch, and takes into account the relative contribution of each parameter to the overall goodness of fit. The procedure is demonstrated on a batch of 50 silicon cells for Space Station Freedom.
10. Parameterization of solar cells
NASA Technical Reports Server (NTRS)
Appelbaum, J.; Chait, A.; Thompson, D.
1992-01-01
The aggregation (sorting) of the individual solar cells into an array is commonly based on a single operating point on the current-voltage (I-V) characteristic curve. An alternative approach for cell performance prediction and cell screening is provided by modeling the cell using an equivalent electrical circuit, in which the parameters involved are related to the physical phenomena in the device. These analytical models may be represented by a double exponential I-V characteristic with seven parameters, by a double exponential model with five parameters, or by a single exponential equation with four or five parameters. In this article we address issues concerning methodologies for the determination of solar cell parameters based on measured data points of the I-V characteristic, and introduce a procedure for screening of solar cells for arrays. We show that common curve fitting techniques, e.g., least squares, may produce many combinations of parameter values while maintaining a good fit between the fitted and measured I-V characteristics of the cell. Therefore, techniques relying on curve fitting criteria alone cannot be directly used for cell parameterization. We propose a consistent procedure which takes into account the entire set of parameter values for a batch of cells. This procedure is based on a definition of a mean cell representing the batch, and takes into account the relative contribution of each parameter to the overall goodness of fit. The procedure is demonstrated on a batch of 50 silicon cells for Space Station Freedom.
11. A Flexible Parameterization for Shortwave Optical Properties of Ice Crystals
NASA Technical Reports Server (NTRS)
VanDiedenhoven, Bastiaan; Ackerman, Andrew S.; Cairns, Brian; Fridlind, Ann M.
2014-01-01
A parameterization is presented that provides extinction cross section sigma (sub e), single-scattering albedo omega, and asymmetry parameter (g) of ice crystals for any combination of volume, projected area, aspect ratio, and crystal distortion at any wavelength in the shortwave. Similar to previous parameterizations, the scheme makes use of geometric optics approximations and the observation that optical properties of complex, aggregated ice crystals can be well approximated by those of single hexagonal crystals with varying size, aspect ratio, and distortion levels. In the standard geometric optics implementation used here, sigma (sub e) is always twice the particle projected area. It is shown that omega is largely determined by the newly defined absorption size parameter and the particle aspect ratio. These dependences are parameterized using a combination of exponential, lognormal, and polynomial functions. The variation of (g) with aspect ratio and crystal distortion is parameterized for one reference wavelength using a combination of several polynomials. The dependences of g on refractive index and omega are investigated and factors are determined to scale the parameterized (g) to provide values appropriate for other wavelengths. The parameterization scheme consists of only 88 coefficients. The scheme is tested for a large variety of hexagonal crystals in several wavelength bands from 0.2 to 4 micron, revealing absolute differences with reference calculations of omega and (g) that are both generally below 0.015. Over a large variety of cloud conditions, the resulting root-mean-squared differences with reference calculations of cloud reflectance, transmittance, and absorptance are 1.4%, 1.1%, and 3.4%, respectively. Some practical applications of the parameterization in atmospheric models are highlighted.
12. Summary of Cumulus Parameterization Workshop
NASA Technical Reports Server (NTRS)
Tao, Wei-Kuo; Starr, David OC.; Hou, Arthur; Newman, Paul; Sud, Yogesh
2002-01-01
A workshop on cumulus parameterization took place at the NASA Goddard Space Flight Center from December 3-5, 2001. The major objectives of this workshop were (1) to review the problem of representation of moist processes in large-scale models (mesoscale models, Numerical Weather Prediction models and Atmospheric General Circulation Models), (2) to review the state-of-the-art in cumulus parameterization schemes, and (3) to discuss the need for future research and applications. There were a total of 31 presentations and about 100 participants from the United States, Japan, the United Kingdom, France and South Korea. The specific presentations and discussions during the workshop are summarized in this paper.
13. Investigation of influences of the paraformaldehyde fixation and paraffin embedding removal process on refractive indices and scattering properties of epithelial cells
Su, Jing-Wei; Hsu, Wei-Chen; Tjiu, Jeng-Wei; Chiang, Chun-Pin; Huang, Chao-Wei; Sung, Kung-Bin
2014-07-01
The scattering properties and refractive indices (RI) of tissue are important parameters in tissue optics. These parameters can be determined from quantitative phase images of thin slices of tissue blocks. However, the changes in RI and structure of cells due to fixation and paraffin embedding might result in inaccuracies in the estimation of the scattering properties of tissue. In this study, three-dimensional RI distributions of cells were measured using digital holographic microtomography to obtain total scattering cross sections (TSCS) of the cells based on the first-order Born approximation. We investigated the slight loss of dry mass and drastic shrinkage of cells due to paraformaldehyde fixation and paraffin embedding removal processes. We propose a method to compensate for the correlated changes in volume and RI of cells. The results demonstrate that the TSCS of live cells can be estimated using restored cells. The percentage deviation of the TSCS between restored cells and live cells was only -8%. Spatially resolved RI and scattering coefficients of unprocessed oral epithelium ranged from 1.35 to 1.39 and from 100 to 450 cm-1, respectively, estimated from paraffin-embedded oral epithelial tissue after restoration of RI and volume.
14. Investigation of influences of the paraformaldehyde fixation and paraffin embedding removal process on refractive indices and scattering properties of epithelial cells.
PubMed
Su, Jing-Wei; Hsu, Wei-Chen; Tjiu, Jeng-Wei; Chiang, Chun-Pin; Huang, Chao-Wei; Sung, Kung-Bin
2014-01-01
The scattering properties and refractive indices (RI) of tissue are important parameters in tissue optics. These parameters can be determined from quantitative phase images of thin slices of tissue blocks. However, the changes in RI and structure of cells due to fixation and paraffin embedding might result in inaccuracies in the estimation of the scattering properties of tissue. In this study, three-dimensional RI distributions of cells were measured using digital holographic microtomography to obtain total scattering cross sections (TSCS) of the cells based on the first-order Born approximation. We investigated the slight loss of dry mass and drastic shrinkage of cells due to paraformaldehyde fixation and paraffin embedding removal processes. We propose a method to compensate for the correlated changes in volume and RI of cells. The results demonstrate that the TSCS of live cells can be estimated using restored cells. The percentage deviation of the TSCS between restored cells and live cells was only −8%. Spatially resolved RI and scattering coefficients of unprocessed oral epithelium ranged from 1.35 to 1.39 and from 100 to 450 cm−1, respectively, estimated from paraffinembedded oral epithelial tissue after restoration of RI and volume.
15. Investigation of influences of the paraformaldehyde fixation and paraffin embedding removal process on refractive indices and scattering properties of epithelial cells.
PubMed
Su, Jing-Wei; Hsu, Wei-Chen; Tjiu, Jeng-Wei; Chiang, Chun-Pin; Huang, Chao-Wei; Sung, Kung-Bin
2014-01-01
The scattering properties and refractive indices (RI) of tissue are important parameters in tissue optics. These parameters can be determined from quantitative phase images of thin slices of tissue blocks. However, the changes in RI and structure of cells due to fixation and paraffin embedding might result in inaccuracies in the estimation of the scattering properties of tissue. In this study, three-dimensional RI distributions of cells were measured using digital holographic microtomography to obtain total scattering cross sections (TSCS) of the cells based on the first-order Born approximation. We investigated the slight loss of dry mass and drastic shrinkage of cells due to paraformaldehyde fixation and paraffin embedding removal processes. We propose a method to compensate for the correlated changes in volume and RI of cells. The results demonstrate that the TSCS of live cells can be estimated using restored cells. The percentage deviation of the TSCS between restored cells and live cells was only −8%. Spatially resolved RI and scattering coefficients of unprocessed oral epithelium ranged from 1.35 to 1.39 and from 100 to 450 cm−1, respectively, estimated from paraffinembedded oral epithelial tissue after restoration of RI and volume. PMID:25069007
16. Kaon-nucleus scattering
NASA Technical Reports Server (NTRS)
Hong, Byungsik; Maung, Khin Maung; Wilson, John W.; Buck, Warren W.
1989-01-01
The derivations of the Lippmann-Schwinger equation and Watson multiple scattering are given. A simple optical potential is found to be the first term of that series. The number density distribution models of the nucleus, harmonic well, and Woods-Saxon are used without t-matrix taken from the scattering experiments. The parameterized two-body inputs, which are kaon-nucleon total cross sections, elastic slope parameters, and the ratio of the real to the imaginary part of the forward elastic scattering amplitude, are presented. The eikonal approximation was chosen as our solution method to estimate the total and absorptive cross sections for the kaon-nucleus scattering.
17. Parameterized Beyond-Einstein Growth
SciTech Connect
Linder, Eric; Linder, Eric V.; Cahn, Robert N.
2007-09-17
A single parameter, the gravitational growth index gamma, succeeds in characterizing the growth of density perturbations in the linear regime separately from the effects of the cosmic expansion. The parameter is restricted to a very narrow range for models of dark energy obeying the laws of general relativity but can take on distinctly different values in models of beyond-Einstein gravity. Motivated by the parameterized post-Newtonian (PPN) formalism for testing gravity, we analytically derive and extend the gravitational growth index, or Minimal Modified Gravity, approach to parameterizing beyond-Einstein cosmology. The analytic formalism demonstrates how to apply the growth index parameter to early dark energy, time-varying gravity, DGP braneworld gravity, and some scalar-tensor gravity.
18. A Novel Shape Parameterization Approach
NASA Technical Reports Server (NTRS)
Samareh, Jamshid A.
1999-01-01
This paper presents a novel parameterization approach for complex shapes suitable for a multidisciplinary design optimization application. The approach consists of two basic concepts: (1) parameterizing the shape perturbations rather than the geometry itself and (2) performing the shape deformation by means of the soft objects animation algorithms used in computer graphics. Because the formulation presented in this paper is independent of grid topology, we can treat computational fluid dynamics and finite element grids in a similar manner. The proposed approach is simple, compact, and efficient. Also, the analytical sensitivity derivatives are easily computed for use in a gradient-based optimization. This algorithm is suitable for low-fidelity (e.g., linear aerodynamics and equivalent laminated plate structures) and high-fidelity analysis tools (e.g., nonlinear computational fluid dynamics and detailed finite element modeling). This paper contains the implementation details of parameterizing for planform, twist, dihedral, thickness, and camber. The results are presented for a multidisciplinary design optimization application consisting of nonlinear computational fluid dynamics, detailed computational structural mechanics, performance, and a simple propulsion module.
19. An accurate parameterization of the infrared radiative properties of cirrus clouds for climate models
SciTech Connect
Fu, Q.; Sun, W.B.; Yang, P.
1998-09-01
An accurate parameterization is presented for the infrared radiative properties of cirrus clouds. For the single-scattering calculations, a composite scheme is developed for randomly oriented hexagonal ice crystals by comparing results from Mie theory, anomalous diffraction theory (ADT), the geometric optics method (GOM), and the finite-difference time domain technique. This scheme employs a linear combination of single-scattering properties from the Mie theory, ADT, and GOM, which is accurate for a wide range of size parameters. Following the approach of Q. Fu, the extinction coefficient, absorption coefficient, and asymmetry factor are parameterized as functions of the cloud ice water content and generalized effective size (D{sub ge}). The present parameterization of the single-scattering properties of cirrus clouds is validated by examining the bulk radiative properties for a wide range of atmospheric conditions. Compared with reference results, the typical relative error in emissivity due to the parameterization is {approximately}2.2%. The accuracy of this parameterization guarantees its reliability in applications to climate models. The present parameterization complements the scheme for the solar radiative properties of cirrus clouds developed by Q. Fu for use in numerical models.
20. An Accurate Parameterization of the Infrared Radiative Properties of Cirrus Clouds for Climate Models.
Fu, Qiang; Yang, Ping; Sun, W. B.
1998-09-01
An accurate parameterization is presented for the infrared radiative properties of cirrus clouds. For the single-scattering calculations, a composite scheme is developed for randomly oriented hexagonal ice crystals by comparing results from Mie theory, anomalous diffraction theory (ADT), the geometric optics method (GOM), and the finite-difference time domain technique. This scheme employs a linear combination of single-scattering properties from the Mie theory, ADT, and GOM, which is accurate for a wide range of size parameters. Following the approach of Q. Fu, the extinction coefficient, absorption coefficient, and asymmetry factor are parameterized as functions of the cloud ice water content and generalized effective size (Dge). The present parameterization of the single-scattering properties of cirrus clouds is validated by examining the bulk radiative properties for a wide range of atmospheric conditions. Compared with reference results, the typical relative error in emissivity due to the parameterization is 2.2%. The accuracy of this parameterization guarantees its reliability in applications to climate models. The present parameterization complements the scheme for the solar radiative properties of cirrus clouds developed by Q. Fu for use in numerical models.
1. A Thermal Infrared Radiation Parameterization for Atmospheric Studies
NASA Technical Reports Server (NTRS)
Chou, Ming-Dah; Suarez, Max J.; Liang, Xin-Zhong; Yan, Michael M.-H.; Cote, Charles (Technical Monitor)
2001-01-01
This technical memorandum documents the longwave radiation parameterization developed at the Climate and Radiation Branch, NASA Goddard Space Flight Center, for a wide variety of weather and climate applications. Based on the 1996-version of the Air Force Geophysical Laboratory HITRAN data, the parameterization includes the absorption due to major gaseous absorption (water vapor, CO2, O3) and most of the minor trace gases (N2O, CH4, CFCs), as well as clouds and aerosols. The thermal infrared spectrum is divided into nine bands. To achieve a high degree of accuracy and speed, various approaches of computing the transmission function are applied to different spectral bands and gases. The gaseous transmission function is computed either using the k-distribution method or the table look-up method. To include the effect of scattering due to clouds and aerosols, the optical thickness is scaled by the single-scattering albedo and asymmetry factor. The parameterization can accurately compute fluxes to within 1% of the high spectral-resolution line-by-line calculations. The cooling rate can be accurately computed in the region extending from the surface to the 0.01-hPa level.
2. Quantum Consequences of Parameterizing Geometry
Wanas, M. I.
2002-12-01
The marriage between geometrization and quantization is not successful, so far. It is well known that quantization of gravity , using known quantization schemes, is not satisfactory. It may be of interest to look for another approach to this problem. Recently, it is shown that geometries with torsion admit quantum paths. Such geometries should be parameterizied in order to preserve the quantum properties appeared in the paths. The present work explores the consequences of parameterizing such geometry. It is shown that quantum properties, appeared in the path equations, are transferred to other geometric entities.
3. Kaon-nucleus scattering
NASA Technical Reports Server (NTRS)
Hong, Byungsik; Buck, Warren W.; Maung, Khin M.
1989-01-01
Two kinds of number density distributions of the nucleus, harmonic well and Woods-Saxon models, are used with the t-matrix that is taken from the scattering experiments to find a simple optical potential. The parameterized two body inputs, which are kaon-nucleon total cross sections, elastic slope parameters, and the ratio of the real to imaginary part of the forward elastic scattering amplitude, are shown. The eikonal approximation was chosen as the solution method to estimate the total and absorptive cross sections for the kaon-nucleus scattering.
4. Using laboratory and field measurements to constrain a single habit shortwave optical parameterization for cirrus
Smith, Helen R.; Baran, Anthony J.; Hesse, Evelyn; Hill, Peter G.; Connolly, Paul J.; Webb, Ann
2016-11-01
A single habit parameterization for the shortwave optical properties of cirrus is presented. The parameterization utilizes a hollow particle geometry, with stepped internal cavities as identified in laboratory and field studies. This particular habit was chosen as both experimental and theoretical results show that the particle exhibits lower asymmetry parameters when compared to solid crystals of the same aspect ratio. The aspect ratio of the particle was varied as a function of maximum dimension, D, in order to adhere to the same physical relationships assumed in the microphysical scheme in a configuration of the Met Office atmosphere-only global model, concerning particle mass, size and effective density. Single scattering properties were then computed using T-Matrix, Ray Tracing with Diffraction on Facets (RTDF) and Ray Tracing (RT) for small, medium, and large size parameters respectively. The scattering properties were integrated over 28 particle size distributions as used in the microphysical scheme. The fits were then parameterized as simple functions of Ice Water Content (IWC) for 6 shortwave bands. The parameterization was implemented into the GA6 configuration of the Met Office Unified Model along with the current operational long-wave parameterization. The GA6 configuration is used to simulate the annual twenty-year short-wave (SW) fluxes at top-of-atmosphere (TOA) and also the temperature and humidity structure of the atmosphere. The parameterization presented here is compared against the current operational model and a more recent habit mixture model.
5. Infrared radiation parameterizations in numerical climate models
NASA Technical Reports Server (NTRS)
Chou, Ming-Dah; Kratz, David P.; Ridgway, William
1991-01-01
This study presents various approaches to parameterizing the broadband transmission functions for utilization in numerical climate models. One-parameter scaling is applied to approximate a nonhomogeneous path with an equivalent homogeneous path, and the diffuse transmittances are either interpolated from precomputed tables or fit by analytical functions. Two-parameter scaling is applied to parameterizing the carbon dioxide and ozone transmission functions in both the lower and middle atmosphere. Parameterizations are given for the nitrous oxide and methane diffuse transmission functions.
6. Parameterization of precipitating shallow convection
Seifert, Axel
2015-04-01
Shallow convective clouds play a decisive role in many regimes of the atmosphere. They are abundant in the trade wind regions and essential for the radiation budget in the sub-tropics. They are also an integral part of the diurnal cycle of convection over land leading to the formation of deeper modes of convection later on. Errors in the representation of these small and seemingly unimportant clouds can lead to misforecasts in many situations. Especially for high-resolution NWP models at 1-3 km grid spacing which explicitly simulate deeper modes of convection, the parameterization of the sub-grid shallow convection is an important issue. Large-eddy simulations (LES) can provide the data to study shallow convective clouds and their interaction with the boundary layer in great detail. In contrast to observation, simulations provide a complete and consistent dataset, which may not be perfectly realistic due to the necessary simplifications, but nevertheless enables us to study many aspects of those clouds in a self-consistent way. Today's supercomputing capabilities make it possible to use domain sizes that not only span several NWP grid boxes, but also allow for mesoscale self-organization of the cloud field, which is an essential behavior of precipitating shallow convection. By coarse-graining the LES data to the grid of an NWP model, the sub-grid fluctuations caused by shallow convective clouds can be analyzed explicitly. These fluctuations can then be parameterized in terms of a PDF-based closure. The necessary choices for such schemes like the shape of the PDF, the number of predicted moments, etc., will be discussed. For example, it is shown that a universal three-parameter distribution of total water may exist at scales of O(1 km) but not at O(10 km). In a next step the variance budgets of moisture and temperature in the cloud-topped boundary layer are studied. What is the role and magnitude of the microphysical correlation terms in these equations, which
7. Parameterization of solar flare dose
SciTech Connect
Lamarche, A.H.; Poston, J.W.
1996-12-31
A critical aspect of missions to the moon or Mars will be the safety and health of the crew. Radiation in space is a hazard for astronauts, especially high-energy radiation following certain types of solar flares. A solar flare event can be very dangerous if astronauts are not adequately shielded because flares can deliver a very high dose in a short period of time. The goal of this research was to parameterize solar flare dose as a function of time to see if it was possible to predict solar flare occurrence, thus providing a warning time. This would allow astronauts to take corrective action and avoid receiving a dose greater than the recommended limit set by the National Council on Radiation Protection and Measurements (NCRP).
8. New Approaches to Parameterizing Convection
NASA Technical Reports Server (NTRS)
Randall, David A.; Lappen, Cara-Lyn
1999-01-01
Many general circulation models (GCMs) currently use separate schemes for planetary boundary layer (PBL) processes, shallow and deep cumulus (Cu) convection, and stratiform clouds. The conventional distinctions. among these processes are somewhat arbitrary. For example, in the stratocumulus-to-cumulus transition region, stratocumulus clouds break up into a combination of shallow cumulus and broken stratocumulus. Shallow cumulus clouds may be considered to reside completely within the PBL, or they may be regarded as starting in the PBL but terminating above it. Deeper cumulus clouds often originate within the PBL with also can originate aloft. To the extent that our models separately parameterize physical processes which interact strongly on small space and time scales, the currently fashionable practice of modularization may be doing more harm than good.
9. Development and application of an interactive cirrus cloud radiative parameterization for global climate models
Joseph, Everette David
1997-12-01
An interactive cirrus cloud radiative parameterization for global climate models is developed and applied. Specifically, a parameterization is presented that predicts the solar cloud optical depth, single scattering albedo and asymmetry factor in terms of cloud effective particle diameter and ice water content. A simple parameterization is developed to predict the infrared cloud emissivity in terms of effective particle diameter and ice water content. Both the solar and infrared parameterizations derive from analytical solutions that treat cirrus cloud particles as hexagonal ice crystals. The cloud microphysical properties, cloud ice content and effective particle diameter, are parameterized in terms of cloud temperature. This interactive cirrus cloud radiative parameterization is incorporated into the NCAR/SUNYA GENESIS atmospheric general circulation model and evaluated in model-to- observation comparisons with a comprehensive set of cloud and radiation data derived from space-based and surface- based measurements obtained during the April 1994 Intensive Observation Period of the Atmospheric Radiation Measurement program. It is shown that the model simulates more realistic solar and infrared radiation incident at the surface with the new cirrus parameterization than with the old. In particular, biases in simulated solar direct and diffuse fluxes are reduced by 60% and 30%, respectively, and that in simulated infrared flux is reduced by 40%. The potential climatic impact of the new cirrus parameterization in a full simulation of the general circulation model is evaluated through instantaneous radiative forcing experiments. The new cirrus parameterization reduces the global annual mean forcing of the surface-atmosphere system by 2.26 Wm-2. This reduction in forcing occurs mainly in the upper troposphere and is dominated by the loss of solar energy in the high latitudes of the summer hemisphere and loss of infrared energy in the tropics during both winter and summer
10. An approach for parameterizing mesoscale precipitating systems
SciTech Connect
Weissbluth, M.J.; Cotton, W.R.
1991-01-01
A cumulus parameterization laboratory has been described which uses a reference numerical model to fabricate, calibrate and verify a cumulus parameterization scheme suitable for use in mesoscale models. Key features of this scheme include resolution independence and the ability to provide hydrometeor source functions to the host model. Thus far, only convective scale drafts have been parameterized, limiting the use of the scheme to those models which can resolve the mesoscale circulations. As it stands, the scheme could probably be incorporated into models having a grid resolution greater than 50 km with results comparable to the existing schemes for the large-scale models. We propose, however, to quantify the mesoscale circulations through the use of the cumulus parameterization laboratory. The inclusion of these mesoscale drafts in the existing scheme will hopefully allow the correct parameterization of the organized mesoscale precipitating systems.
11. An approach for parameterizing mesoscale precipitating systems
SciTech Connect
Weissbluth, M.J.; Cotton, W.R.
1991-12-31
A cumulus parameterization laboratory has been described which uses a reference numerical model to fabricate, calibrate and verify a cumulus parameterization scheme suitable for use in mesoscale models. Key features of this scheme include resolution independence and the ability to provide hydrometeor source functions to the host model. Thus far, only convective scale drafts have been parameterized, limiting the use of the scheme to those models which can resolve the mesoscale circulations. As it stands, the scheme could probably be incorporated into models having a grid resolution greater than 50 km with results comparable to the existing schemes for the large-scale models. We propose, however, to quantify the mesoscale circulations through the use of the cumulus parameterization laboratory. The inclusion of these mesoscale drafts in the existing scheme will hopefully allow the correct parameterization of the organized mesoscale precipitating systems.
12. Parameterization of Shortwave Cloud Optical Properties for a Mixture of Ice Particle Habits for use in Atmospheric Models
NASA Technical Reports Server (NTRS)
Chou, Ming-Dah; Lee, Kyu-Tae; Yang, Ping; Lau, William K. M. (Technical Monitor)
2002-01-01
Based on the single-scattering optical properties pre-computed with an improved geometric optics method, the bulk absorption coefficient, single-scattering albedo, and asymmetry factor of ice particles have been parameterized as a function of the effective particle size of a mixture of ice habits, the ice water amount, and spectral band. The parameterization has been applied to computing fluxes for sample clouds with various particle size distributions and assumed mixtures of particle habits. It is found that flux calculations are not overly sensitive to the assumed particle habits if the definition of the effective particle size is consistent with the particle habits that the parameterization is based. Otherwise, the error in the flux calculations could reach a magnitude unacceptable for climate studies. Different from many previous studies, the parameterization requires only an effective particle size representing all ice habits in a cloud layer, but not the effective size of individual ice habits.
13. Parameterized Linear Longitudinal Airship Model
NASA Technical Reports Server (NTRS)
Kulczycki, Eric; Elfes, Alberto; Bayard, David; Quadrelli, Marco; Johnson, Joseph
2010-01-01
A parameterized linear mathematical model of the longitudinal dynamics of an airship is undergoing development. This model is intended to be used in designing control systems for future airships that would operate in the atmospheres of Earth and remote planets. Heretofore, the development of linearized models of the longitudinal dynamics of airships has been costly in that it has been necessary to perform extensive flight testing and to use system-identification techniques to construct models that fit the flight-test data. The present model is a generic one that can be relatively easily specialized to approximate the dynamics of specific airships at specific operating points, without need for further system identification, and with significantly less flight testing. The approach taken in the present development is to merge the linearized dynamical equations of an airship with techniques for estimation of aircraft stability derivatives, and to thereby make it possible to construct a linearized dynamical model of the longitudinal dynamics of a specific airship from geometric and aerodynamic data pertaining to that airship. (It is also planned to develop a model of the lateral dynamics by use of the same methods.) All of the aerodynamic data needed to construct the model of a specific airship can be obtained from wind-tunnel testing and computational fluid dynamics
14. A Two-Habit Ice Cloud Optical Property Parameterization for GCM Application
NASA Technical Reports Server (NTRS)
Yi, Bingqi; Yang, Ping; Minnis, Patrick; Loeb, Norman; Kato, Seiji
2014-01-01
We present a novel ice cloud optical property parameterization based on a two-habit ice cloud model that has been proved to be optimal for remote sensing applications. The two-habit ice model is developed with state-of-the-art numerical methods for light scattering property calculations involving individual columns and column aggregates with the habit fractions constrained by in-situ measurements from various field campaigns. Band-averaged bulk ice cloud optical properties including the single-scattering albedo, the mass extinction/absorption coefficients, and the asymmetry factor are parameterized as functions of the effective particle diameter for the spectral bands involved in the broadband radiative transfer models. Compared with other parameterization schemes, the two-habit scheme generally has lower asymmetry factor values (around 0.75 at the visible wavelengths). The two-habit parameterization scheme was widely tested with the broadband radiative transfer models (i.e. Rapid Radiative Transfer Model, GCM version) and global circulation models (GCMs, i.e. Community Atmosphere Model, version 5). Global ice cloud radiative effects at the top of the atmosphere are also analyzed from the GCM simulation using the two-habit parameterization scheme in comparison with CERES satellite observations.
15. Swept Volume Parameterization for Isogeometric Analysis
Aigner, M.; Heinrich, C.; Jüttler, B.; Pilgerstorfer, E.; Simeon, B.; Vuong, A.-V.
Isogeometric Analysis uses NURBS representations of the domain for performing numerical simulations. The first part of this paper presents a variational framework for generating NURBS parameterizations of swept volumes. The class of these volumes covers a number of interesting free-form shapes, such as blades of turbines and propellers, ship hulls or wings of airplanes. The second part of the paper reports the results of isogeometric analysis which were obtained with the help of the generated NURBS volume parameterizations. In particular we discuss the influence of the chosen parameterization and the incorporation of boundary conditions.
16. Parameterization of Cloud Optical Properties for a Mixture of Ice Particles for use in Atmospheric Models
NASA Technical Reports Server (NTRS)
Chou, Ming-Dah; Lee, Kyu-Tae; Yang, Ping; Lau, William K. M. (Technical Monitor)
2002-01-01
Based on the single-scattering optical properties that are pre-computed using an improve geometric optics method, the bulk mass absorption coefficient, single-scattering albedo, and asymmetry factor of ice particles have been parameterized as a function of the mean effective particle size of a mixture of ice habits. The parameterization has been applied to compute fluxes for sample clouds with various particle size distributions and assumed mixtures of particle habits. Compared to the parameterization for a single habit of hexagonal column, the solar heating of clouds computed with the parameterization for a mixture of habits is smaller due to a smaller cosingle-scattering albedo. Whereas the net downward fluxes at the TOA and surface are larger due to a larger asymmetry factor. The maximum difference in the cloud heating rate is approx. 0.2 C per day, which occurs in clouds with an optical thickness greater than 3 and the solar zenith angle less than 45 degrees. Flux difference is less than 10 W per square meters for the optical thickness ranging from 0.6 to 10 and the entire range of the solar zenith angle. The maximum flux difference is approximately 3%, which occurs around an optical thickness of 1 and at high solar zenith angles.
17. Methods of testing parameterizations: Vertical ocean mixing
NASA Technical Reports Server (NTRS)
Tziperman, Eli
1992-01-01
The ocean's velocity field is characterized by an exceptional variety of scales. While the small-scale oceanic turbulence responsible for the vertical mixing in the ocean is of scales a few centimeters and smaller, the oceanic general circulation is characterized by horizontal scales of thousands of kilometers. In oceanic general circulation models that are typically run today, the vertical structure of the ocean is represented by a few tens of discrete grid points. Such models cannot explicitly model the small-scale mixing processes, and must, therefore, find ways to parameterize them in terms of the larger-scale fields. Finding a parameterization that is both reliable and plausible to use in ocean models is not a simple task. Vertical mixing in the ocean is the combined result of many complex processes, and, in fact, mixing is one of the less known and less understood aspects of the oceanic circulation. In present models of the oceanic circulation, the many complex processes responsible for vertical mixing are often parameterized in an oversimplified manner. Yet, finding an adequate parameterization of vertical ocean mixing is crucial to the successful application of ocean models to climate studies. The results of general circulation models for quantities that are of particular interest to climate studies, such as the meridional heat flux carried by the ocean, are quite sensitive to the strength of the vertical mixing. We try to examine the difficulties in choosing an appropriate vertical mixing parameterization, and the methods that are available for validating different parameterizations by comparing model results to oceanographic data. First, some of the physical processes responsible for vertically mixing the ocean are briefly mentioned, and some possible approaches to the parameterization of these processes in oceanographic general circulation models are described in the following section. We then discuss the role of the vertical mixing in the physics of the
18. Toward a macroscopic parameterization of iceberg calving
Amundson, J. M.
2014-12-01
Parameterization of iceberg calving for prognostic glacier and ice sheet models remains a major challenge due to a poor understanding of the physical processes governing calving. Here, I propose a semi-empirical, macroscopic parameterization of calving that ignores the complex physics of the glacier-ocean interface, can be applied to any calving margin, and is easy to implement with very little computational cost. To test the parameterization, I apply it to a one-dimensional flowline model of an Alaskan-style tidewater glacier and subject the model to various climatic forcings. The model produces results that are roughly consistent with observations, i.e., rapid retreat and flow acceleration through an overdeepening over decades and slow re-advance over millenia. Model results are compared to the previously proposed water depth, height above flotation, and crevasse-depth calving parameterizations to show that they are consistent with the macroscopic parameterization under certain conditions. Although there remains a great deal of uncertainty in the exact form of the macroscopic parameterization, it does appear to be a promising and simple way to model the glacier-ocean boundary.
19. Optical closure of parameterized bio-optical relationships
He, Shuangyan; Fischer, Jürgen; Schaale, Michael; He, Ming-xia
2014-03-01
An optical closure study on bio-optical relationships was carried out using radiative transfer model matrix operator method developed by Freie Universität Berlin. As a case study, the optical closure of bio-optical relationships empirically parameterized with in situ data for the East China Sea was examined. Remote-sensing reflectance ( R rs) was computed from the inherent optical properties predicted by these biooptical relationships and compared with published in situ data. It was found that the simulated R rs was overestimated for turbid water. To achieve optical closure, bio-optical relationships for absorption and scattering coefficients for suspended particulate matter were adjusted. Furthermore, the results show that the Fournier and Forand phase functions obtained from the adjusted relationships perform better than the Petzold phase function. Therefore, before bio-optical relationships are used for a local sea area, the optical closure should be examined.
20. Parameterization of lattice spacings for lipid multilayers in ionic solutions
Petrache, Horia; Johnson, Merrell; Harries, Daniel; Seifert, Soenke
Lipids, which are molecules found in biological cells, form highly regular layered structures called multilamellar lipid vesicles (MLVs). The repeat lattice spacings of MLVs depend on van der Waals and electrostatic forces between neighboring membranes and are sensitive to the presence of salt. For example, addition of salt ions such as sodium and potassium makes the MLVs swell, primarily due to changes in electrical polarizabilities. However, a more complicated behavior is found in some ionic solutions such as those containing lithium ions. Using x-ray scattering, we show experimentally how the interactions between membranes depend on the type of monovalent ions and construct parameterizations of MLVs swelling curves that can help analyze van der Waals interactions.
1. Parameterization of the three-dimensional room transfer function in horizontal plane.
PubMed
Bu, Bing; Abhayapala, Thushara D; Bao, Chang-chun; Zhang, Wen
2015-09-01
This letter proposes an efficient parameterization of the three-dimensional room transfer function (RTF) which is robust for the position variations of source and receiver in respective horizontal planes. Based on azimuth harmonic analysis, the proposed method exploits the underlying properties of the associated Legendre functions to remove a portion of the spherical harmonic coefficients of RTF which have no contribution in the horizontal plane. This reduction leads to a flexible measuring-point structure consisting of practical concentric circular arrays to extract horizontal plane RTF coefficients. The accuracy of the above parameterization is verified through numerical simulations. PMID:26428827
2. A parameterization of cloud droplet nucleation
SciTech Connect
Ghan, S.J.; Chuang, C.C.; Penner, J.E.
1994-01-01
Droplet nucleation is a fundamental cloud process. The number of aerosols activated to form cloud droplets influences not only the number of aerosols scavenged by clouds but also the size of the cloud droplets. Cloud droplet size influences the cloud albedo and the conversion of cloud water to precipitation. Global aerosol models are presently being developed with the intention of coupling with global atmospheric circulation models to evaluate the influence of aerosols and aerosol-cloud interactions on climate. If these and other coupled models are to address issues of aerosol-interactions, the droplet nucleation process must be adequately represented. Ghan et al. have introduced a droplet nucleation parameterization for a single aerosol type that offers certain advantages over the popular Twomey parameterization. Here we describe the generalization of that parameterization to the case of multiple aerosol types, with estimation of aerosol mass as well as number activated.
3. POET: Parameterized Optimization for Empirical Tuning
SciTech Connect
Yi, Q; Seymour, K; You, H; Vuduc, R; Quinlan, D
2007-01-29
The excessive complexity of both machine architectures and applications have made it difficult for compilers to statically model and predict application behavior. This observation motivates the recent interest in performance tuning using empirical techniques. We present a new embedded scripting language, POET (Parameterized Optimization for Empirical Tuning), for parameterizing complex code transformations so that they can be empirically tuned. The POET language aims to significantly improve the generality, flexibility, and efficiency of existing empirical tuning systems. We have used the language to parameterize and to empirically tune three loop optimizations-interchange, blocking, and unrolling-for two linear algebra kernels. We show experimentally that the time required to tune these optimizations using POET, which does not require any program analysis, is significantly shorter than that when using a full compiler-based source-code optimizer which performs sophisticated program analysis and optimizations.
4. Approaches for Subgrid Parameterization: Does Scaling Help?
Yano, Jun-Ichi
2016-04-01
Arguably the scaling behavior is a well-established fact in many geophysical systems. There are already many theoretical studies elucidating this issue. However, the scaling law is slow to be introduced in "operational" geophysical modelling, notably for weather forecast as well as climate projection models. The main purpose of this presentation is to ask why, and try to answer this question. As a reference point, the presentation reviews the three major approaches for traditional subgrid parameterization: moment, PDF (probability density function), and mode decomposition. The moment expansion is a standard method for describing the subgrid-scale turbulent flows both in the atmosphere and the oceans. The PDF approach is intuitively appealing as it directly deals with a distribution of variables in subgrid scale in a more direct manner. The third category, originally proposed by Aubry et al (1988) in context of the wall boundary-layer turbulence, is specifically designed to represent coherencies in compact manner by a low--dimensional dynamical system. Their original proposal adopts the proper orthogonal decomposition (POD, or empirical orthogonal functions, EOF) as their mode-decomposition basis. However, the methodology can easily be generalized into any decomposition basis. The mass-flux formulation that is currently adopted in majority of atmospheric models for parameterizing convection can also be considered a special case of the mode decomposition, adopting the segmentally-constant modes for the expansion basis. The mode decomposition can, furthermore, be re-interpreted as a type of Galarkin approach for numerically modelling the subgrid-scale processes. Simple extrapolation of this re-interpretation further suggests us that the subgrid parameterization problem may be re-interpreted as a type of mesh-refinement problem in numerical modelling. We furthermore see a link between the subgrid parameterization and downscaling problems along this line. The mode
5. A uniform parameterization of moment tensors
Tape, C.; Tape, W.
2015-12-01
A moment tensor is a 3 x 3 symmetric matrix that expresses an earthquake source. We construct a parameterization of the five-dimensional space of all moment tensors of unit norm. The coordinates associated with the parameterization are closely related to moment tensor orientations and source types. The parameterization is uniform, in the sense that equal volumes in the coordinate domain of the parameterization correspond to equal volumes of moment tensors. Uniformly distributed points in the coordinate domain therefore give uniformly distributed moment tensors. A cartesian grid in the coordinate domain can be used to search efficiently over moment tensors. We find that uniformly distributed moment tensors have uniformly distributed orientations (eigenframes), but that their source types (eigenvalue triples) are distributed so as to favor double couples. An appropriate choice of a priori moment tensor probability is a prerequisite for parameter estimation. As a seemingly sensible choice, we consider the homogeneous probability, in which equal volumes of moment tensors are equally likely. We believe that it will lead to improved characterization of source processes.
6. Parameterizing cloud condensation nuclei concentrations during HOPE
Hande, Luke B.; Engler, Christa; Hoose, Corinna; Tegen, Ina
2016-09-01
An aerosol model was used to simulate the generation and transport of aerosols over Germany during the HD(CP)2 Observational Prototype Experiment (HOPE) field campaign of 2013. The aerosol number concentrations and size distributions were evaluated against observations, which shows satisfactory agreement in the magnitude and temporal variability of the main aerosol contributors to cloud condensation nuclei (CCN) concentrations. From the modelled aerosol number concentrations, number concentrations of CCN were calculated as a function of vertical velocity using a comprehensive aerosol activation scheme which takes into account the influence of aerosol chemical and physical properties on CCN formation. There is a large amount of spatial variability in aerosol concentrations; however the resulting CCN concentrations vary significantly less over the domain. Temporal variability is large in both aerosols and CCN. A parameterization of the CCN number concentrations is developed for use in models. The technique involves defining a number of best fit functions to capture the dependence of CCN on vertical velocity at different pressure levels. In this way, aerosol chemical and physical properties as well as thermodynamic conditions are taken into account in the new CCN parameterization. A comparison between the parameterization and the CCN estimates from the model data shows excellent agreement. This parameterization may be used in other regions and time periods with a similar aerosol load; furthermore, the technique demonstrated here may be employed in regions dominated by different aerosol species.
7. Empirical parameterization of setup, swash, and runup
USGS Publications Warehouse
Stockdon, H.F.; Holman, R.A.; Howd, P.A.; Sallenger, A.H.
2006-01-01
Using shoreline water-level time series collected during 10 dynamically diverse field experiments, an empirical parameterization for extreme runup, defined by the 2% exceedence value, has been developed for use on natural beaches over a wide range of conditions. Runup, the height of discrete water-level maxima, depends on two dynamically different processes; time-averaged wave setup and total swash excursion, each of which is parameterized separately. Setup at the shoreline was best parameterized using a dimensional form of the more common Iribarren-based setup expression that includes foreshore beach slope, offshore wave height, and deep-water wavelength. Significant swash can be decomposed into the incident and infragravity frequency bands. Incident swash is also best parameterized using a dimensional form of the Iribarren-based expression. Infragravity swash is best modeled dimensionally using offshore wave height and wavelength and shows no statistically significant linear dependence on either foreshore or surf-zone slope. On infragravity-dominated dissipative beaches, the magnitudes of both setup and swash, modeling both incident and infragravity frequency components together, are dependent only on offshore wave height and wavelength. Statistics of predicted runup averaged over all sites indicate a - 17 cm bias and an rms error of 38 cm: the mean observed runup elevation for all experiments was 144 cm. On intermediate and reflective beaches with complex foreshore topography, the use of an alongshore-averaged beach slope in practical applications of the runup parameterization may result in a relative runup error equal to 51% of the fractional variability between the measured and the averaged slope.
8. Parameterization of daily solar global ultraviolet irradiation.
PubMed
Feister, U; Jäkel, E; Gericke, K
2002-09-01
9. Control of shortwave radiation parameterization on tropical climate SST-forced simulation
Crétat, Julien; Masson, Sébastien; Berthet, Sarah; Samson, Guillaume; Terray, Pascal; Dudhia, Jimy; Pinsard, Françoise; Hourdin, Christophe
2016-09-01
SST-forced tropical-channel simulations are used to quantify the control of shortwave (SW) parameterization on the mean tropical climate compared to other major model settings (convection, boundary layer turbulence, vertical and horizontal resolutions), and to pinpoint the physical mechanisms whereby this control manifests. Analyses focus on the spatial distribution and magnitude of the net SW radiation budget at the surface (SWnet_SFC), latent heat fluxes, and rainfall at the annual timescale. The model skill and sensitivity to the tested settings are quantified relative to observations and using an ensemble approach. Persistent biases include overestimated SWnet_SFC and too intense hydrological cycle. However, model skill is mainly controlled by SW parameterization, especially the magnitude of SWnet_SFC and rainfall and both the spatial distribution and magnitude of latent heat fluxes over ocean. On the other hand, the spatial distribution of continental rainfall (SWnet_SFC) is mainly influenced by convection parameterization and horizontal resolution (boundary layer parameterization and orography). Physical understanding of the control of SW parameterization is addressed by analyzing the thermal structure of the atmosphere and conducting sensitivity experiments to O3 absorption and SW scattering coefficient. SW parameterization shapes the stability of the atmosphere in two different ways according to whether surface is coupled to atmosphere or not, while O3 absorption has minor effects in our simulations. Over SST-prescribed regions, increasing the amount of SW absorption warms the atmosphere only because surface temperatures are fixed, resulting in increased atmospheric stability. Over land-atmosphere coupled regions, increasing SW absorption warms both atmospheric and surface temperatures, leading to a shift towards a warmer state and a more intense hydrological cycle. This turns in reversal model behavior between land and sea points, with the SW scheme that
10. Parameterization of contrail radiative properties for climate studies
Xie, Yu; Yang, Ping; Liou, Kuo-Nan; Minnis, Patrick; Duda, David P.
2012-12-01
The study of contrails and their impact on global climate change requires a cloud model that statistically represents contrail radiative properties. In this study, the microphysical properties of global contrails are statistically analyzed using collocated Moderate Resolution Imaging Spectroradiometer (MODIS) and Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) observations. The MODIS contrail pixels are detected using an automated contrail detection algorithm and a manual technique using the brightness temperature differences between the MODIS 11 and 12 μm channels. The scattering and absorption properties of typical contrail ice crystals are used to determine an appropriate contrail model to minimize the uncertainties arising from the assumptions in a particular cloud model. The depolarization ratio is simulated with a variety of ice crystal habit fractions and matched to the collocated MODIS and CALIOP observations. The contrail habit fractions are determined and used to compute the bulk-scattering properties of contrails. A parameterization of shortwave and longwave contrail optical properties is developed for the spectral bands of the Rapid Radiative Transfer Model (RRTM). The contrail forcing at the top of the atmosphere is investigated using the RRTM and compared with spherical and hexagonal ice cloud models. Contrail forcing is overestimated when spherical ice crystals are used to represent contrails, but if a hexagonal ice cloud model is used, the forcing is underestimated for small particles and overestimated for large particles in comparison to the contrail model developed in this study.
11. A Simple Parameterization of 3 x 3 Magic Squares
ERIC Educational Resources Information Center
Trenkler, Gotz; Schmidt, Karsten; Trenkler, Dietrich
2012-01-01
In this article a new parameterization of magic squares of order three is presented. This parameterization permits an easy computation of their inverses, eigenvalues, eigenvectors and adjoints. Some attention is paid to the Luoshu, one of the oldest magic squares.
12. European upper mantle tomography: adaptively parameterized models
Schäfer, J.; Boschi, L.
2009-04-01
We have devised a new algorithm for upper-mantle surface-wave tomography based on adaptive parameterization: i.e. the size of each parameterization pixel depends on the local density of seismic data coverage. The advantage in using this kind of parameterization is that a high resolution can be achieved in regions with dense data coverage while a lower (and cheaper) resolution is kept in regions with low coverage. This way, parameterization is everywhere optimal, both in terms of its computational cost, and of model resolution. This is especially important for data sets with inhomogenous data coverage, as it is usually the case for global seismic databases. The data set we use has an especially good coverage around Switzerland and over central Europe. We focus on periods from 35s to 150s. The final goal of the project is to determine a new model of seismic velocities for the upper mantle underlying Europe and the Mediterranean Basin, of resolution higher than what is currently found in the literature. Our inversions involve regularization via norm and roughness minimization, and this in turn requires that discrete norm and roughness operators associated with our adaptive grid be precisely defined. The discretization of the roughness damping operator in the case of adaptive parameterizations is not as trivial as it is for the uniform ones; important complications arise from the significant lateral variations in the size of pixels. We chose to first define the roughness operator in a spherical harmonic framework, and subsequently translate it to discrete pixels via a linear transformation. Since the smallest pixels we allow in our parameterization have a size of 0.625 °, the spherical-harmonic roughness operator has to be defined up to harmonic degree 899, corresponding to 810.000 harmonic coefficients. This results in considerable computational costs: we conduct the harmonic-pixel transformations on a small Beowulf cluster. We validate our implementation of adaptive
13. Parameterization of cloud effects on the absorption of solar radiation
NASA Technical Reports Server (NTRS)
Davies, R.
1983-01-01
A radiation parameterization for the NASA Goddard climate model was developed, tested, and implemented. Interactive and off-hire experiments with the climate model to determine the limitations of the present parameterization scheme are summarized. The parameterization of Cloud absorption in terms of solar zeith angle, column water vapors about the cloud top, and cloud liquid water content is discussed.
14. Cloud parameterization for climate modeling - Status and prospects
NASA Technical Reports Server (NTRS)
Randall, David A.
1989-01-01
The current status of cloud parameterization research is reviewed. It is emphasized that the upper tropospheric stratiform clouds associated with deep convection are both physically important and poorly parameterized in current models. Emerging parameterizations are described in general terms, with emphasis on prognostic cloud water and fractional cloudiness, and how these relate to the problem just mentioned.
15. Numerical Archetypal Parameterization for Mesoscale Convective Systems
Yano, J. I.
2015-12-01
Vertical shear tends to organize atmospheric moist convection into multiscale coherent structures. Especially, the counter-gradient vertical transport of horizontal momentum by organized convection can enhance the wind shear and transport kinetic energy upscale. However, this process is not represented by traditional parameterizations. The present paper sets the archetypal dynamical models, originally formulated by the second author, into a parameterization context by utilizing a nonhydrostatic anelastic model with segmentally-constant approximation (NAM-SCA). Using a two-dimensional framework as a starting point, NAM-SCA spontaneously generates propagating tropical squall-lines in a sheared environment. A high numerical efficiency is achieved through a novel compression methodology. The numerically-generated archetypes produce vertical profiles of convective momentum transport that are consistent with the analytic archetype.
16. Aerosol water parameterization: a single parameter framework
Metzger, S.; Steil, B.; Abdelkader, M.; Klingmüller, K.; Xu, L.; Penner, J. E.; Fountoukis, C.; Nenes, A.; Lelieveld, J.
2015-11-01
We introduce a framework to efficiently parameterize the aerosol water uptake for mixtures of semi-volatile and non-volatile compounds, based on the coefficient, νi. This solute specific coefficient was introduced in Metzger et al. (2012) to accurately parameterize the single solution hygroscopic growth, considering the Kelvin effect - accounting for the water uptake of concentrated nanometer sized particles up to dilute solutions, i.e., from the compounds relative humidity of deliquescence (RHD) up to supersaturation (Köhler-theory). Here we extend the νi-parameterization from single to mixed solutions. We evaluate our framework at various levels of complexity, by considering the full gas-liquid-solid partitioning for a comprehensive comparison with reference calculations using the E-AIM, EQUISOLV II, ISORROPIA II models as well as textbook examples. We apply our parameterization in EQSAM4clim, the EQuilibrium Simplified Aerosol Model V4 for climate simulations, implemented in a box model and in the global chemistry-climate model EMAC. Our results show: (i) that the νi-approach enables to analytically solve the entire gas-liquid-solid partitioning and the mixed solution water uptake with sufficient accuracy, (ii) that, e.g., pure ammonium nitrate and mixed ammonium nitrate - ammonium sulfate mixtures can be solved with a simple method, and (iii) that the aerosol optical depth (AOD) simulations are in close agreement with remote sensing observations for the year 2005. Long-term evaluation of the EMAC results based on EQSAM4clim and ISORROPIA II will be presented separately.
17. A Survey of Shape Parameterization Techniques
NASA Technical Reports Server (NTRS)
Samareh, Jamshid A.
1999-01-01
This paper provides a survey of shape parameterization techniques for multidisciplinary optimization and highlights some emerging ideas. The survey focuses on the suitability of available techniques for complex configurations, with suitability criteria based on the efficiency, effectiveness, ease of implementation, and availability of analytical sensitivities for geometry and grids. The paper also contains a section on field grid regeneration, grid deformation, and sensitivity analysis techniques.
18. Implicit Shape Parameterization for Kansei Design Methodology
Nordgren, Andreas Kjell; Aoyama, Hideki
Implicit shape parameterization for Kansei design is a procedure that use 3D-models, or concepts, to span a shape space for surfaces in the automotive field. A low-dimensional, yet accurate shape descriptor was found by Principal Component Analysis of an ensemble of point-clouds, which were extracted from mesh-based surfaces modeled in a CAD-program. A theoretical background of the procedure is given along with step-by-step instructions for the required data-processing. The results show that complex surfaces can be described very efficiently, and encode design features by an implicit approach that does not rely on error-prone explicit parameterizations. This provides a very intuitive way to explore shapes for a designer, because various design features can simply be introduced by adding new concepts to the ensemble. Complex shapes have been difficult to analyze with Kansei methods due to the large number of parameters involved, but implicit parameterization of design features provides a low-dimensional shape descriptor for efficient data collection, model-building and analysis of emotional content in 3D-surfaces.
19. A GCM parameterization for the shortwave radiative properties of water clouds
NASA Technical Reports Server (NTRS)
Slingo, A.
1990-01-01
A new parameterization was developed for predicting the shortwave radiative properties of water clouds, suitable for inclusion in general circulation models (GCMs). The parameterization makes use of the simple relationships found by Slingo and Schrecker, giving the three input parameters required to calculate the cloud radiative properties (the optical depth, single scatter albedo and asymmetry parameter) in terms of the liquid water path and equivalent radius of the drop size distribution. The input parameters are then used to derive the cloud radiative properties, using standard two-stream equations for a single layer. The relationships were originally derived for fairly narrow spectral bands but it was found that it is possible to average the coefficients so as to use a much smaller number of bands, without sacrificing accuracy in calculating the cloud radiative properties. This makes the parameterization fast enough to be included in GCMs. The parameterization was programmed into the radiation scheme used in the U.K. Meteorological Office GCM. This scheme and the 24 band Slingo/Schrecker scheme were compared with each other and with observations, using a variety of published datasets. There is good agreement between the two schemes for both cloud albedo and absorption, even when only four spectral bands are employed in the GCM.
20. Quantitative Ultrasonic Characterization of Diffuse Scatterers in the Presence of Structures That Produce Coherent Echoes
PubMed Central
Luchies, Adam C.; Ghoshal, Goutam; O’Brien, William D.; Oelze, Michael L.
2012-01-01
Quantitative ultrasound (QUS) techniques that parameterize the backscattered power spectrum have demonstrated significant promise for ultrasonic tissue characterization. Some QUS parameters, such as the effective scatterer diameter (ESD), require the assumption that the examined medium contains uniform diffuse scatterers. Structures that invalidate this assumption can significantly affect the estimated QUS parameters and decrease performance when classifying disease. In this work, a method was developed to reduce the effects of echoes that invalidate the assumption of diffuse scattering. To accomplish this task, backscattered signal sections containing non-diffuse echoes were identified and removed from the QUS analysis. Parameters estimated from the generalized spectrum (GS) and the Rayleigh SNR parameter were compared for detecting data blocks with non-diffuse echoes. Simulations and experiments were used to evaluate the effectiveness of the method. Experiments consisted of estimating QUS parameters from spontaneous fibroadenomas in rats and from beef liver samples. Results indicated that the method was able to significantly reduce or eliminate the effects of non-diffuse echoes that might exist in the backscattered signal. For example, the average reduction in the relative standard deviation of ESD estimates from simulation, rat fibroadenomas, and beef liver samples were 13%, 30%, and 51%, respectively. The Rayleigh SNR parameter performed best at detecting non-diffuse echoes for the purpose of removing and reducing ESD bias and variance. The method provides a means to improve the diagnostic capabilities of QUS techniques by allowing separate analysis of diffuse and non-diffuse scatterers. PMID:22622974
1. Parameterization Impacts on Linear Uncertainty Calculation
Fienen, M. N.; Doherty, J.; Reeves, H. W.; Hunt, R. J.
2009-12-01
Efficient linear calculation of model prediction uncertainty can be an insightful diagnostic metric for decision-making. Specifically, the contributions of parameter uncertainty or the location and type of data to prediction uncertainty can be used to evaluate which types of information are most valuable. Information that most significantly reduces prediction uncertainty can be considered to have greater worth. Prediction uncertainty is commonly calculated including or excluding specific information and compared to a base scenario. The quantitative difference in uncertainty with or without the information is indicative of that information's worth in the decision-making process. These results can be calculated at many hypothetical locations to guide network design (i.e., where to install new wells/stream gages/etc.) or used to indicate which parameters are the most important to understand thus likely candidates for future characterization work. We examine a hypothetical case in which an inset model is created from a large regional model in order to better represent a surface stream network and make predictions of head near and flux in a stream due to installation and pumping of a large well near a stream headwater. Parameterization and edge boundary conditions are inherited from the regional model, the simple act of refining discretization and stream geometry shows improvement in the representation of the streams. Even visual inspection of the simulated head field highlights the need to recalibrate and potentially re-parametrize the inset model. A network of potential head observations is evaluated and contoured in the shallowest two layers of the six-layer model to assess their worth in both predicting flux at a specific gage, and head at a specific location near the stream. Three hydraulic conductivity parameterization scenarios are evaluated: using a single multiplier on hydraulic conductivity acting on the inherited hydraulic conductivity zonation using; the
2. Neutron detector resolution for scattering
SciTech Connect
Kolda, S.A.
1997-03-01
A resolution function has been determined for scattered neutron experiments at Rensselaer Polytechnic Institute (RPI). This function accounts for the shifting and broadening of the resonance peak due to the additional path length, traveled by the neutron after scattering and prior to detection, along with the broadening of the resonance peak due to the bounce target. This resolution function has been parameterized both in neutron energy and size of the sample disk. Monte Carlo Neutron and Photon (MCNP) modeling has been used to determine the shape of the detector resolution function while assuming that the sample nucleus has an infinite mass. The shape of the function for a monoenergetic neutron point source has been compared to the analytical solution. Additionally, the parameterized detector resolution function has been used to broaden the scatter yield calculated from Evaluated Neutron Data File ENDF/B-VI cross section data for {sup 238}U. The target resolution function has been empirically determined by comparison of the broadened scatter yield and the experimental yield for {sup 238}U. The combined resolution function can be inserted into the SAMMY code to allow resonance analysis for scattering measurements.
3. Lightning parameterization in a storm electrification model
NASA Technical Reports Server (NTRS)
Helsdon, John H., Jr.; Farley, Richard D.; Wu, Gang
1988-01-01
The parameterization of an intracloud lightning discharge has been implemented in our Storm Electrification Model. The initiation, propagation direction, termination and charge redistribution of the discharge are approximated assuming overall charge neutrality. Various simulations involving differing amounts of charge transferred have been done. The effects of the lightning-produced ions on the hydrometeor charges, electric field components and electrical energy depend strongly on the charge transferred. A comparison between the measured electric field change of an actual intracloud flash and the field change due to the simulated discharge show favorable agreement.
4. A parameterization of the evaporation of rainfall
NASA Technical Reports Server (NTRS)
Schlesinger, Michael E.; Oh, Jai-Ho; Rosenfeld, Daniel
1988-01-01
A general theoretical expression for the rainfall rate and the total evaporation rate as a function of the distance below cloud base is developed, and is then specialized to the gamma raindrop size distribution. The theoretical framework is used to analyze the data of Rosenfeld and Mintz (1988) on the radar observations of the rainfall rate as a function of the distance below cloud base, for rain falling from continental convective cells in central South Africa, obtaining a parameterization for the evaporation of rainfall.
5. Born approximation, scattering, and algorithm
Martinez, Alex; Hu, Mengqi; Gu, Haicheng; Qiao, Zhijun
2015-05-01
In the past few decades, there were many imaging algorithms designed in the case of the absence of multiple scattering. Recently, we discussed an algorithm for removing high order scattering components from collected data. This paper is a continuation of our previous work. First, we investigate the current state of multiple scattering in SAR. Then, we revise our method and test it. Given an estimate of our target reflectivity, we compute the multi scattering effects in the target region for various frequencies. Furthermore, we propagate this energy through free space towards our antenna, and remove it from the collected data.
6. Intercomparison of land-surface parameterizations launched
Henderson-Sellers, A.; Dickinson, R. E.
One of the crucial tasks for climatic and hydrological scientists over the next several years will be validating land surface process parameterizations used in climate models. There is not, necessarily, a unique set of parameters to be used. Different scientists will want to attempt to capture processes through various methods “for example, Avissar and Verstraete, 1990”. Validation of some aspects of the available (and proposed) schemes' performance is clearly required. It would also be valuable to compare the behavior of the existing schemes [for example, Dickinson et al., 1991; Henderson-Sellers, 1992a].The WMO-CAS Working Group on Numerical Experimentation (WGNE) and the Science Panel of the GEWEX Continental-Scale International Project (GCIP) [for example, Chahine, 1992] have agreed to launch the joint WGNE/GCIP Project for Intercomparison of Land-Surface Parameterization Schemes (PILPS). The principal goal of this project is to achieve greater understanding of the capabilities and potential applications of existing and new land-surface schemes in atmospheric models. It is not anticipated that a single “best” scheme will emerge. Rather, the aim is to explore alternative models in ways compatible with their authors' or exploiters' goals and to increase understanding of the characteristics of these models in the scientific community.
7. Mixing parameterizations in ocean climate modeling
Moshonkin, S. N.; Gusev, A. V.; Zalesny, V. B.; Byshev, V. I.
2016-03-01
Results of numerical experiments with an eddy-permitting ocean circulation model on the simulation of the climatic variability of the North Atlantic and the Arctic Ocean are analyzed. We compare the ocean simulation quality with using different subgrid mixing parameterizations. The circulation model is found to be sensitive to a mixing parametrization. The computation of viscosity and diffusivity coefficients by an original splitting algorithm of the evolution equations for turbulence characteristics is found to be as efficient as traditional Monin-Obukhov parameterizations. At the same time, however, the variability of ocean climate characteristics is simulated more adequately. The simulation of salinity fields in the entire study region improves most significantly. Turbulent processes have a large effect on the circulation in the long-term through changes in the density fields. The velocity fields in the Gulf Stream and in the entire North Atlantic Subpolar Cyclonic Gyre are reproduced more realistically. The surface level height in the Arctic Basin is simulated more faithfully, marking the Beaufort Gyre better. The use of the Prandtl number as a function of the Richardson number improves the quality of ocean modeling.
8. A new parameterization of spectral and broadband ocean surface albedo.
PubMed
Jin, Zhonghai; Qiao, Yanli; Wang, Yingjian; Fang, Yonghua; Yi, Weining
2011-12-19
A simple yet accurate parameterization of spectral and broadband ocean surface albedo has been developed. To facilitate the parameterization and its applications, the albedo is parameterized for the direct and diffuse incident radiation separately, and then each of them is further divided into two components: the contributions from surface and water, respectively. The four albedo components are independent of each other, hence, altering one will not affect the others. Such a designed parameterization scheme is flexible for any future update. Users can simply replace any of the adopted empirical formulations (e.g., the relationship between foam reflectance and wind speed) as desired without a need to change the parameterization scheme. The parameterization is validated by in situ measurements and can be easily implemented into a climate or radiative transfer model. PMID:22274228
9. BRAIN SURFACE CONFORMAL PARAMETERIZATION WITH THE RICCI FLOW
PubMed Central
Wang, Yalin; Gu, Xianfeng; Chan, Tony F.; Thompson, Paul M.; Yau, Shing-Tung
2013-01-01
In medical imaging, parameterized 3D surface models are of great interest for anatomical modeling and visualization, statistical comparisons of anatomy, and surface-based registration and signal processing. By solving the Yamabe equation with the Ricci flow method, we can conformally parameterize a brain surface via a mapping to a multi-hole disk. The resulting parameterizations do not have any singularities and are intrinsic and stable. To illustrate the technique, we computed parameterizations of cortical surfaces in MRI scans of the brain. We also show the parameterization results are consistent with constraints imposed on the mappings of selected landmark curves, and the resulting surfaces can be matched to each other using constrained harmonic maps. Unlike previous planar conformal parameterization methods, our algorithm does not introduce any singularity points. PMID:21926017
10. Parameterization of Solar Global Uv Irradiation
Feister, U.; Jaekel, E.; Gericke, K.
11. Optika : a GUI framework for parameterized applications.
SciTech Connect
Nusbaum, Kurtis L.
2011-06-01
In the field of scientific computing there are many specialized programs designed for specific applications in areas such as biology, chemistry, and physics. These applications are often very powerful and extraordinarily useful in their respective domains. However, some suffer from a common problem: a non-intuitive, poorly-designed user interface. The purpose of Optika is to address this problem and provide a simple, viable solution. Using only a list of parameters passed to it, Optika can dynamically generate a GUI. This allows the user to specify parameters values in a fashion that is much more intuitive than the traditional 'input decks' used by some parameterized scientific applications. By leveraging the power of Optika, these scientific applications will become more accessible and thus allow their designers to reach a much wider audience while requiring minimal extra development effort.
12. Planet temperatures with surface cooling parameterized
Levenson, Barton Paul
2011-06-01
A semigray (shortwave and longwave) surface temperature model is developed from conditions on Venus, Earth and Mars, where the greenhouse effect is mostly due to carbon dioxide and water vapor. In addition to estimating longwave optical depths, parameterizations are developed for surface cooling due to shortwave absorption in the atmosphere, and for convective (sensible and latent) heat transfer. An approximation to the Clausius-Clapeyron relation provides water-vapor feedback. The resulting iterative algorithm is applied to three "super-Earths" in the Gliese 581 system, including the "Goldilocks" planet g ( Vogt et al., 2010). Surprisingly, none of the three appear habitable. One cannot accurately locate a star's habitable zone without data or assumptions about a planet's atmosphere.
13. A Genus Oblivious Approach to Cross Parameterization
SciTech Connect
Bennett, J C; Pascucci, V; Joy, K I
2008-06-16
In this paper we present a robust approach to construct a map between two triangulated meshes, M and M{prime} of arbitrary and possibly unequal genus. We introduce a novel initial alignment scheme that allows the user to identify 'landmark tunnels' and/or a 'constrained silhouette' in addition to the standard landmark vertices. To describe the evolution of non-landmark tunnels we automatically derive a continuous deformation from M to M{prime} using a variational implicit approach. Overall, we achieve a cross parameterization scheme that is provably robust in the sense that it can map M to M{prime} without constraints on their relative genus. We provide a number of examples to demonstrate the practical effectiveness of our scheme between meshes of different genus and shape.
14. The natural parameterization of cosmic neutrino oscillations
2015-09-01
The natural parameterization of vacuum oscillations in three neutrino flavors is studied. Compact and exact relations of its three parameters with the ordinary three mixing angles and CP-violating phase are obtained. Its usefulness is illustrated by considering various applications: the study of the flavor ratio and of its uncertainties, the comparison of expectations and observations in the flavor triangle, and the intensity of the signal due to Glashow resonance. The results in the literature are easily reproduced and in particular the recently obtained agreement of the observations of IceCube with the hypothesis of cosmic neutrino oscillations is confirmed. It is argued that a Gaussian treatment of the errors appropriately describes the effects of the uncertainties on the neutrino oscillation parameters.
15. Cumulus parameterizations in chemical transport models
Mahowald, Natalie M.; Rasch, Philip J.; Prinn, Ronald G.
1995-12-01
Global three-dimensional chemical transport models (CTMs) are valuable tools for studying processes controlling the distribution of trace constituents in the atmosphere. A major uncertainty in these models is the subgrid-scale parametrization of transport by cumulus convection. This study seeks to define the range of behavior of moist convective schemes and point toward more reliable formulations for inclusion in chemical transport models. The emphasis is on deriving convective transport from meteorological data sets (such as those from the forecast centers) which do not routinely include convective mass fluxes. Seven moist convective parameterizations are compared in a column model to examine the sensitivity of the vertical profile of trace gases to the parameterization used in a global chemical transport model. The moist convective schemes examined are the Emanuel scheme [Emanuel, 1991], the Feichter-Crutzen scheme [Feichter and Crutzen, 1990], the inverse thermodynamic scheme (described in this paper), two versions of a scheme suggested by Hack [Hack, 1994], and two versions of a scheme suggested by Tiedtke (one following the formulation used in the ECMWF (European Centre for Medium-Range Weather Forecasting) and ECHAM3 (European Centre and Hamburg Max-Planck-Institut) models [Tiedtke, 1989], and one formulated as in the TM2 (Transport Model-2) model (M. Heimann, personal communication, 1992). These convective schemes vary in the closure used to derive the mass fluxes, as well as the cloud model formulation, giving a broad range of results. In addition, two boundary layer schemes are compared: a state-of-the-art nonlocal boundary layer scheme [Holtslag and Boville, 1993] and a simple adiabatic mixing scheme described in this paper. Three tests are used to compare the moist convective schemes against observations. Although the tests conducted here cannot conclusively show that one parameterization is better than the others, the tests are a good measure of the
16. Toward parameterization of the stable boundary layer
NASA Technical Reports Server (NTRS)
Wetzel, P. J.
1982-01-01
Wangara data is used to examine the depth of the nocturnal boundary layer (NBL) and the height to which surface-linked turbulence extends. It is noted that a linearity of virtual temperature profiles has been found to extend up to a significant portion of the NBL, and then diverge where the wind shear rides over the surface-induced turbulence. A series of Richardson numbers are examined for varying degrees of turbulence and the significant cooling region is observed to have greater depth than the depth of the linear relationship layer. A three-layer parameterization of the thermodynamic structure of the NBL is developed so that a system of five equations must be solved when the wind velocity profile and the temperature at the surface are known. A correlation between the bulk Richardson number and the depth of the linear layer was found to be 0.89.
17. Climate impacts of parameterized Nordic Sea overflows
Danabasoglu, Gokhan; Large, William G.; Briegleb, Bruce P.
2010-11-01
A new overflow parameterization (OFP) of density-driven flows through ocean ridges via narrow, unresolved channels has been developed and implemented in the ocean component of the Community Climate System Model version 4. It represents exchanges from the Nordic Seas and the Antarctic shelves, associated entrainment, and subsequent injection of overflow product waters into the abyssal basins. We investigate the effects of the parameterized Denmark Strait (DS) and Faroe Bank Channel (FBC) overflows on the ocean circulation, showing their impacts on the Atlantic Meridional Overturning Circulation and the North Atlantic climate. The OFP is based on the Marginal Sea Boundary Condition scheme of Price and Yang (1998), but there are significant differences that are described in detail. Two uncoupled (ocean-only) and two fully coupled simulations are analyzed. Each pair consists of one case with the OFP and a control case without this parameterization. In both uncoupled and coupled experiments, the parameterized DS and FBC source volume transports are within the range of observed estimates. The entrainment volume transports remain lower than observational estimates, leading to lower than observed product volume transports. Due to low entrainment, the product and source water properties are too similar. The DS and FBC overflow temperature and salinity properties are in better agreement with observations in the uncoupled case than in the coupled simulation, likely reflecting surface flux differences. The most significant impact of the OFP is the improved North Atlantic Deep Water penetration depth, leading to a much better comparison with the observational data and significantly reducing the chronic, shallow penetration depth bias in level coordinate models. This improvement is due to the deeper penetration of the southward flowing Deep Western Boundary Current. In comparison with control experiments without the OFP, the abyssal ventilation rates increase in the North
18. Parameterizing Size Distribution in Ice Clouds
SciTech Connect
DeSlover, Daniel; Mitchell, David L.
2009-09-25
PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 µm) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 µm), known as the “small mode”. Rather than using in situ probe measurements aboard aircraft, we employed a treatment of ice
19. On the factorization and fitting of molecular scattering information
NASA Technical Reports Server (NTRS)
Goldflam, R.; Kouri, D. J.; Green, S.
1977-01-01
The reported analysis is based on the factored IOS T-matrix. It is shown that line shape measurements may be used over a range of temperatures to evaluate inelastic scattering cross sections. Basic factorization or parameterization relations are derived by considering the wavefunction equations. The parameterization of cross sections is considered, taking into account the differential scattering amplitude and cross section, integral cross sections, phenomenological cross sections for general relaxation processes, and viscosity and diffusion cross sections. Thermal averages and rates are discussed, giving attention to integral cross sections and rates, and general phenomenological cross sections. The results of computational studies are also presented.
20. Parameterized Complexity of Eulerian Deletion Problems.
PubMed
Cygan, Marek; Marx, Dániel; Pilipczuk, Marcin; Pilipczuk, Michał; Schlotter, Ildikó
2014-01-01
We study a family of problems where the goal is to make a graph Eulerian, i.e., connected and with all the vertices having even degrees, by a minimum number of deletions. We completely classify the parameterized complexity of various versions: undirected or directed graphs, vertex or edge deletions, with or without the requirement of connectivity, etc. The collection of results shows an interesting contrast: while the node-deletion variants remain intractable, i.e., W[1]-hard for all the studied cases, edge-deletion problems are either fixed-parameter tractable or polynomial-time solvable. Of particular interest is a randomized FPT algorithm for making an undirected graph Eulerian by deleting the minimum number of edges, based on a novel application of the color coding technique. For versions that remain NP-complete but fixed-parameter tractable we consider also possibilities of polynomial kernelization; unfortunately, we prove that this is not possible unless NP⊆coNP/poly. PMID:24415818
1. Brain Surface Conformal Parameterization Using Riemann Surface Structure
PubMed Central
Wang, Yalin; Lui, Lok Ming; Gu, Xianfeng; Hayashi, Kiralee M.; Chan, Tony F.; Toga, Arthur W.; Thompson, Paul M.; Yau, Shing-Tung
2011-01-01
In medical imaging, parameterized 3-D surface models are useful for anatomical modeling and visualization, statistical comparisons of anatomy, and surface-based registration and signal processing. Here we introduce a parameterization method based on Riemann surface structure, which uses a special curvilinear net structure (conformal net) to partition the surface into a set of patches that can each be conformally mapped to a parallelogram. The resulting surface subdivision and the parameterizations of the components are intrinsic and stable (their solutions tend to be smooth functions and the boundary conditions of the Dirichlet problem can be enforced). Conformal parameterization also helps transform partial differential equations (PDEs) that may be defined on 3-D brain surface manifolds to modified PDEs on a two-dimensional parameter domain. Since the Jacobian matrix of a conformal parameterization is diagonal, the modified PDE on the parameter domain is readily solved. To illustrate our techniques, we computed parameterizations for several types of anatomical surfaces in 3-D magnetic resonance imaging scans of the brain, including the cerebral cortex, hippocampi, and lateral ventricles. For surfaces that are topologically homeomorphic to each other and have similar geometrical structures, we show that the parameterization results are consistent and the subdivided surfaces can be matched to each other. Finally, we present an automatic sulcal landmark location algorithm by solving PDEs on cortical surfaces. The landmark detection results are used as constraints for building conformal maps between surfaces that also match explicitly defined landmarks. PMID:17679336
2. Parameterizing deep convection using the assumed probability density function method
DOE PAGES
Storer, R. L.; Griffin, B. M.; Höft, J.; Weber, J. K.; Raut, E.; Larson, V. E.; Wang, M.; Rasch, P. J.
2014-06-11
Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method. The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and mid-latitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing ismore » weak. The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.« less
3. Parameterizing deep convection using the assumed probability density function method
SciTech Connect
Storer, R. L.; Griffin, B. M.; Hoft, Jan; Weber, J. K.; Raut, E.; Larson, Vincent E.; Wang, Minghuai; Rasch, Philip J.
2015-01-06
Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method.The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and mid-latitude deep convection.These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing is weak. The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.
4. Parameterizing deep convection using the assumed probability density function method
DOE PAGES
Storer, R. L.; Griffin, B. M.; Höft, J.; Weber, J. K.; Raut, E.; Larson, V. E.; Wang, M.; Rasch, P. J.
2015-01-06
Due to their coarse horizontal resolution, present-day climate models must parameterize deep convection. This paper presents single-column simulations of deep convection using a probability density function (PDF) parameterization. The PDF parameterization predicts the PDF of subgrid variability of turbulence, clouds, and hydrometeors. That variability is interfaced to a prognostic microphysics scheme using a Monte Carlo sampling method. The PDF parameterization is used to simulate tropical deep convection, the transition from shallow to deep convection over land, and midlatitude deep convection. These parameterized single-column simulations are compared with 3-D reference simulations. The agreement is satisfactory except when the convective forcing ismore » weak. The same PDF parameterization is also used to simulate shallow cumulus and stratocumulus layers. The PDF method is sufficiently general to adequately simulate these five deep, shallow, and stratiform cloud cases with a single equation set. This raises hopes that it may be possible in the future, with further refinements at coarse time step and grid spacing, to parameterize all cloud types in a large-scale model in a unified way.« less
5. A process-based fire parameterization of intermediate complexity in a Dynamic Global Vegetation Model
Li, F.; Zeng, X. D.; Levis, S.
2012-03-01
A process-based fire parameterization of intermediate complexity has been developed for global simulations in the framework of a Dynamic Global Vegetation Model (DGVM) in an Earth System Model (ESM). Burned area in a grid cell is estimated by the product of fire counts and average burned area per fire. The scheme comprises three parts: fire occurrence, fire spread, and fire impact. In the fire occurrence part, fire counts rather than fire occurrence probability is calculated in order to capture the observed high burned area fraction in regions where fire occurs frequently. In the fire spread part, post-fire region of a fire is assumed to be elliptical in shape. Mathematical properties of ellipses and mathematical derivation are applied to remove redundant and unreasonable equation and assumptions in existing fire spread parameterization. In the fire impact part, trace gas and aerosol emissions due to biomass burning are estimated, which offers an interface with atmospheric chemistry and aerosol models in ESMs. In addition, flexible time-step length makes the new fire parameterization easily applied to various DGVMs. Global performance of the new fire parameterization is assessed by using an improved version of the Community Land Model version 3 with the Dynamic Global Vegetation Model (CLM-DGVM). Simulations are compared against the latest satellite-based Global Fire Emission Database version 3 (GFED3) for 1997-2004. Results show that simulated global totals and spatial patterns of burned area and fire carbon emissions, global annual burned area fractions for various vegetation types and interannual variability of burned area are in close agreement with the GFED3, and more accurate than CLM-DGVM simulations with the commonly used Glob-FIRM fire parameterization and the old fire module of CLM-DGVM. Furthermore, the average relative error of simulated trace gas and aerosol emissions due to biomass burning is 7 %. Results suggest that the new fire parameterization may
6. Concept of polarization entropy in optical scattering
Cloude, Shane R.; Pottier, Eric
1995-06-01
We consider the application of the general theory of unitary matrices to problems of wave scattering involving polarized waves. Having outlined useful parameterizations of the low dimensional groups associated with these unitary matrices, we develop a general processing strategy, which we suggest has application in the extraction of physical information from a range of scattering matrices in optics. Examples are presented of applying the unitary matrix structure to problems of single and multiple scattering from a cloud of random particles. The techniques are best suited to characterization of depolarizing systems, where the scattered waves undergo a change of degree as well as polarization state. The degree of disorder of the system is then quantified by a scalar, the polarimetric entropy, defined from the eigenvalues of a scattering matrix that ranges from 0 for systems with zero scattering to 1 for perfect depolarizers. Further, we show that the unitary matrix parameterization can be used to extract important system information from the eigenvectors of this matrix.
7. Climate and the equilibrium state of land surface hydrology parameterizations
NASA Technical Reports Server (NTRS)
Entekhabi, Dara; Eagleson, Peter S.
1991-01-01
For given climatic rates of precipitation and potential evaporation, the land surface hydrology parameterizations of atmospheric general circulation models will maintain soil-water storage conditions that balance the moisture input and output. The surface relative soil saturation for such climatic conditions serves as a measure of the land surface parameterization state under a given forcing. The equilibrium value of this variable for alternate parameterizations of land surface hydrology are determined as a function of climate and the sensitivity of the surface to shifts and changes in climatic forcing are estimated.
8. CORTICAL SURFACE PARAMETERIZATION BY P-HARMONIC ENERGY MINIMIZATION
PubMed Central
JOSHI, ANAND A.; SHATTUCK, DAVID W.; THOMPSON, PAUL M.; LEAHY, RICHARD M.
2010-01-01
Cortical surface parameterization has several applications in visualization and analysis of the brain surface. Here we propose a scheme for parameterizing the surface of the cerebral cortex. The parameterization is formulated as the minimization of an energy functional in the pth norm. A numerical method for obtaining the solution is also presented. Brain surfaces from multiple subjects are brought into common parameter space using the scheme. 3D spatial averages of the cortical surfaces are generated by using the correspondences induced by common parameter space. PMID:20721316
9. Parameterization of cloud glaciation by atmospheric dust
Nickovic, Slobodan; Cvetkovic, Bojan; Madonna, Fabio; Pejanovic, Goran; Petkovic, Slavko
2016-04-01
The exponential growth of research interest on ice nucleation (IN) is motivated, inter alias, by needs to improve generally unsatisfactory representation of cold cloud formation in atmospheric models, and therefore to increase the accuracy of weather and climate predictions, including better forecasting of precipitation. Research shows that mineral dust significantly contributes to cloud ice nucleation. Samples of residual particles in cloud ice crystals collected by aircraft measurements performed in the upper tropopause of regions distant from desert sources indicate that dust particles dominate over other known ice nuclei such as soot and biological particles. In the nucleation process, dust chemical aging had minor effects. The observational evidence on IN processes has substantially improved over the last decade and clearly shows that there is a significant correlation between IN concentrations and the concentrations of coarser aerosol at a given temperature and moisture. Most recently, due to recognition of the dominant role of dust as ice nuclei, parameterizations for immersion and deposition icing specifically due to dust have been developed. Based on these achievements, we have developed a real-time forecasting coupled atmosphere-dust modelling system capable to operationally predict occurrence of cold clouds generated by dust. We have been thoroughly validated model simulations against available remote sensing observations. We have used the CNR-IMAA Potenza lidar and cloud radar observations to explore the model capability to represent vertical features of the cloud and aerosol vertical profiles. We also utilized the MSG-SEVIRI and MODIS satellite data to examine the accuracy of the simulated horizontal distribution of cold clouds. Based on the obtained encouraging verification scores, operational experimental prediction of ice clouds nucleated by dust has been introduced in the Serbian Hydrometeorological Service as a public available product.
10. Parameterization of cirrus optical depth and cloud fraction
SciTech Connect
Soden, B.
1995-09-01
This research illustrates the utility of combining satellite observations and operational analysis for the evaluation of parameterizations. A parameterization based on ice water path (IWP) captures the observed spatial patterns of tropical cirrus optical depth. The strong temperature dependence of cirrus ice water path in both the observations and the parameterization is probably responsible for the good correlation where it exists. Poorer agreement is found in Southern Hemisphere mid-latitudes where the temperature dependence breaks down. Uncertainties in effective radius limit quantitative validation of the parameterization (and its inclusion into GCMs). Also, it is found that monthly mean cloud cover can be predicted within an RMS error of 10% using ECMWF relative humidity corrected by TOVS Upper Troposphere Humidity. 1 ref., 2 figs.
11. Some applications of parameterized Picard-Vessiot theory
Mitschi, C.
2016-02-01
This is an expository article describing some applications of parameterized Picard-Vessiot theory. This Galois theory for parameterized linear differential equations was Cassidy and Singer's contribution to an earlier volume dedicated to the memory of Andrey Bolibrukh. The main results we present here were obtained for families of ordinary differential equations with parameterized regular singularities in joint work with Singer. They include parametric versions of Schlesinger's theorem and of the weak Riemann-Hilbert problem as well as an algebraic characterization of a special type of monodromy evolving deformations illustrated by the classical Darboux-Halphen equation. Some of these results have recently been applied by different authors to solve the inverse problem of parameterized Picard-Vessiot theory, and were also generalized to irregular singularities. We sketch some of these results by other authors. The paper includes a brief history of the Darboux-Halphen equation as well as an appendix on differentially closed fields.
12. Towards Quantitative Optical Cross Sections in Entomological Laser Radar – Potential of Temporal and Spherical Parameterizations for Identifying Atmospheric Fauna
PubMed Central
Brydegaard, Mikkel
2015-01-01
In recent years, the field of remote sensing of birds and insects in the atmosphere (the aerial fauna) has advanced considerably, and modern electro-optic methods now allow the assessment of the abundance and fluxes of pests and beneficials on a landscape scale. These techniques have the potential to significantly increase our understanding of, and ability to quantify and manage, the ecological environment. This paper presents a concept whereby laser radar observations of atmospheric fauna can be parameterized and table values for absolute cross sections can be catalogued to allow for the study of focal species such as disease vectors and pests. Wing-beat oscillations are parameterized with a discrete set of harmonics and the spherical scatter function is parameterized by a reduced set of symmetrical spherical harmonics. A first order spherical model for insect scatter is presented and supported experimentally, showing angular dependence of wing beat harmonic content. The presented method promises to give insights into the flight heading directions of species in the atmosphere and has the potential to shed light onto the km-range spread of pests and disease vectors. PMID:26295706
13. Experimenting with a Convective Parameterization Scheme Suitable for High-Resolution Mesoscale Models in Tropical Cyclone Simulations
Grell, Evelyn; Grell, Georg; Bao, Jian-Wen
2013-04-01
Results from numerical experiments using high-resolution mesoscale models have presented evidence that the use of the explicit microphysics scheme only at grid spacing from few hundred meters to a few kilometers is often not sufficient to neutralize moist instability within the grid box. A consequence of such a problem is that artificial grid-point storms may occur, which in tropical cyclone simulations can lead to erroneous representation of tropical cyclone development. The use of conventional sub-grid convection parameterization schemes to alleviate artificial grid-point storms is not appropriate in this situation since these schemes assume that the updraft area is much smaller than the model grid spacing and this assumption becomes invalid when the grid size is a few kilometers or smaller. A sub-grid convection scheme suitable for high-resolution mesoscale models has been developed by Grell and Freitas (2013) to remove the aforementioned assumption used in conventional sub-grid convection parameterization schemes. This scheme can be used for grid spacing equal to or smaller than a few kilometers to help sufficiently remove moist instability for the entire grid point. This scheme behaves similarly to conventional schemes when the updraft area is much smaller than the grids size. As the updraft area in a grid box approaches the grid size, the parameterized sub-grid convection gradually diminishes. This presentation highlights major results from experimenting with this newly developed scheme in the Advanced Research WRF (ARW) model with an idealized tropical cyclone intensification case. We will demonstrate the scheme converges (i.e., the parameterized convection diminishes as the updraft area in a grid box approaches the grid size) using the change of the intensity of parameterized sub-grid convection with the decrease in grid size. We will also discuss the issues and challenges in refining this scheme for its application in operational models.
14. A Gaussian-product stochastic Gent-McWilliams parameterization
Grooms, Ian
2016-10-01
The locally-averaged horizontal buoyancy flux by mesoscale eddies is computed from eddy-resolving quasigeostrophic simulations of ocean-mesoscale eddy dynamics. This flux has a very non-Gaussian distribution peaked at zero, not at the mean value. This non-Gaussian flux distribution arises because the flux is a product of zero-mean random variables: the eddy velocity and buoyancy. A framework for stochastic Gent-McWilliams (GM) parameterization is presented. Gaussian random field models for subgrid-scale velocity and buoyancy are developed. The product of these Gaussian random fields is used to construct a non-Gaussian stochastic parameterization of the horizontal subgrid-scale density flux, which leads to a non-Gaussian stochastic GM parameterization. This new non-Gaussian stochastic GM parameterization is tested in an idealized box ocean model, and compared to a Gaussian approach that simply multiplies the deterministic GM parameterization by a Gaussian random field. The non-Gaussian approach has a significant impact on both the mean and variability of the simulations, more so than the Gaussian approach; for example, the non-Gaussian simulation has a much larger net kinetic energy and a stronger overturning circulation than a comparable Gaussian simulation. Future directions for development of the stochastic GM parameterization and extensions of the Gaussian-product approach are discussed.
15. Parameter Estimation and Parameterization Uncertainty Using Bayesian Model Averaging
Tsai, F. T.; Li, X.
2007-12-01
This study proposes Bayesian model averaging (BMA) to address parameter estimation uncertainty arisen from non-uniqueness in parameterization methods. BMA provides a means of incorporating multiple parameterization methods for prediction through the law of total probability, with which an ensemble average of hydraulic conductivity distribution is obtained. Estimation uncertainty is described by the BMA variances, which contain variances within and between parameterization methods. BMA shows the facts that considering more parameterization methods tends to increase estimation uncertainty and estimation uncertainty is always underestimated using a single parameterization method. Two major problems in applying BMA to hydraulic conductivity estimation using a groundwater inverse method will be discussed in the study. The first problem is the use of posterior probabilities in BMA, which tends to single out one best method and discard other good methods. This problem arises from Occam's window that only accepts models in a very narrow range. We propose a variance window to replace Occam's window to cope with this problem. The second problem is the use of Kashyap information criterion (KIC), which makes BMA tend to prefer high uncertain parameterization methods due to considering the Fisher information matrix. We found that Bayesian information criterion (BIC) is a good approximation to KIC and is able to avoid controversial results. We applied BMA to hydraulic conductivity estimation in the 1,500-foot sand aquifer in East Baton Rouge Parish, Louisiana.
16. Faster Parameterized Algorithms for Minor Containment
Adler, Isolde; Dorn, Frederic; Fomin, Fedor V.; Sau, Ignasi; Thilikos, Dimitrios M.
The theory of Graph Minors by Robertson and Seymour is one of the deepest and significant theories in modern Combinatorics. This theory has also a strong impact on the recent development of Algorithms, and several areas, like Parameterized Complexity, have roots in Graph Minors. Until very recently it was a common belief that Graph Minors Theory is mainly of theoretical importance. However, it appears that many deep results from Robertson and Seymour's theory can be also used in the design of practical algorithms. Minor containment testing is one of algorithmically most important and technical parts of the theory, and minor containment in graphs of bounded branchwidth is a basic ingredient of this algorithm. In order to implement minor containment testing on graphs of bounded branchwidth, Hicks [NETWORKS 04] described an algorithm, that in time O(3^{k^2}\\cdot (h+k-1)!\\cdot m) decides if a graph G with m edges and branchwidth k, contains a fixed graph H on h vertices as a minor. That algorithm follows the ideas introduced by Robertson and Seymour in [J'CTSB 95]. In this work we improve the dependence on k of Hicks' result by showing that checking if H is a minor of G can be done in time O(2^{(2k +1 )\\cdot log k} \\cdot h^{2k} \\cdot 2^{2h^2} \\cdot m). Our approach is based on a combinatorial object called rooted packing, which captures the properties of the potential models of subgraphs of H that we seek in our dynamic programming algorithm. This formulation with rooted packings allows us to speed up the algorithm when G is embedded in a fixed surface, obtaining the first single-exponential algorithm for minor containment testing. Namely, it runs in time 2^{O(k)} \\cdot h^{2k} \\cdot 2^{O(h)} \\cdot n, with n = |V(G)|. Finally, we show that slight modifications of our algorithm permit to solve some related problems within the same time bounds, like induced minor or contraction minor containment.
17. Quantifying and Parameterizing the Transport of Sub-Cloud Layer Moisture and Reactants by Shallow Cumulus Clouds over Land
Ouwersloot, H. G.; van Stratum, B. J.; Vila-Guerau Arellano, J.; Sikma, M.; Krol, M. C.; Lelieveld, J.
2013-12-01
We investigate the vertical transport of moisture and atmospheric chemical reactants from the sub-cloud layer to the cumulus cloud layer related to the kinematic mass flux that is driven by shallow convection over land. The dynamical and chemical assumptions needed for mesoscale and global chemistry-transport model parameterizations are systematically analysed using numerical experiments performed by a Large-Eddy Simulation (LES) model. First, we identify and discuss the four primary feedback mechanisms between sub-cloud layer dynamics and mass-flux transport by shallow cumulus clouds for typical mid-latitude conditions. These feedbacks involve mixed-layer drying and heating, changing the moisture variability at the sub-cloud layer top and adjusting entrainment. Based on this analysis and LES experiments, we design parameterizations for cloud properties and mass-flux transport of air and moisture that can be applied to large-scale models. As an intermediate step, we incorporate the parameterizations in a conceptual mixed-layer model, which enables us to study these interplays in more detail. By comparing the results of this model with LES case studies, we show for a wide range of conditions that the new parameterizations enable the model to reproduce the sub-cloud layer dynamics and the four aforementioned feedbacks. However, by considering heterogeneous sensible and latent heat fluxes at the surface, we demonstrate that the parameterizations are sensitive to specific boundary conditions due to changes in the boundary-layer dynamics. Second, we extend the investigation to determine whether the parameterizations are suitable for tropical conditions and to represent the transport of reactants. The numerical experiments in this analysis are inspired by observations over the Amazon during the dry season. Isoprene, a key atmospheric compound over the tropical rain forest, decreases by 8.5 % hr-1 on average and 15 % hr-1 at maximum due to mass-flux induced removal. The
18. Deep convection in the Arctic: The evaluation of results from an OGCM with a new convection parameterization
SciTech Connect
Paluszkiewicz, T.; Hibler, L.F.; Romea, R.D.
1995-01-01
The current generation of ocean general circulation models (OGCMS) uses a convective adjustment scheme to remove static instabilities and to parameterize shallow and deep convection. In simulations used to examine climate-related scenarios, investigators found that in the Arctic regions, the OGCM simulations did not produce a realistic vertical density structure, did not create the correct quantity of deep water, and did not use a time-scale of adjustment that is in agreement with tracer ages or observations. A possible weakness of the models is that the convective adjustment scheme does not represent the process of deep convection adequately. Consequently, a penetrative plume mixing scheme has been developed to parameterize the process of deep open-ocean convection in OGCMS. This new deep convection parameterization was incorporated into the Semtner and Chervin (1988) OGCM. The modified model (with the new parameterization) was run in a simplified Nordic Seas test basin: under a cyclonic wind stress and cooling, stratification of the basin-scale gyre is eroded and deep mixing occurs in the center of the gyre. In contrast, in the OGCM experiment that uses the standard convective adjustment algorithm, mixing is delayed and is wide-spread over the gyre.
19. How certain are the process parameterizations in our models?
Gharari, Shervan; Hrachowitz, Markus; Fenicia, Fabrizio; Matgen, Patrick; Razavi, Saman; Savenije, Hubert; Gupta, Hoshin; Wheater, Howard
2016-04-01
Environmental models are abstract simplifications of real systems. As a result, the elements of these models, including system architecture (structure), process parameterization and parameters inherit a high level of approximation and simplification. In a conventional model building exercise the parameter values are the only elements of a model which can vary while the rest of the modeling elements are often fixed a priori and therefore not subjected to change. Once chosen the process parametrization and model structure usually remains the same throughout the modeling process. The only flexibility comes from the changing parameter values, thereby enabling these models to reproduce the desired observation. This part of modeling practice, parameter identification and uncertainty, has attracted a significant attention in the literature during the last years. However what remains unexplored in our point of view is to what extent the process parameterization and system architecture (model structure) can support each other. In other words "Does a specific form of process parameterization emerge for a specific model given its system architecture and data while no or little assumption has been made about the process parameterization itself? In this study we relax the assumption regarding a specific pre-determined form for the process parameterizations of a rainfall/runoff model and examine how varying the complexity of the system architecture can lead to different or possibly contradictory parameterization forms than what would have been decided otherwise. This comparison implicitly and explicitly provides us with an assessment of how uncertain is our perception of model process parameterization in respect to the extent the data can support.
20. How uncertain are the process parameterizations in our models?
Hrachowitz, M.; Gharari, S.; Gupta, H. V.; Fenicia, F.; Matgen, P.; Savenije, H.
2015-12-01
Environmental models are abstract simplifications of real systems. As a result, the elements of these models, including system architecture (structure), process parameterization and parameters inherit a high level of approximation and simplification. In a conventional model building exercise the parameter values are the only elements of a model which can vary while the rest of the modeling elements are often fixed a priori and therefore not subjected to change. Once chosen the process parametrization and model structure usually remains the same throughout the modeling process. The only flexibility comes from the changing parameter values, thereby enabling these models to reproduce the desired observation. This part of modeling practice, parameter identification and uncertainty, has attracted a significant attention in the literature during the last years. However what remains unexplored in our point of view is to what extent the process parameterization and system architecture (model structure) can support each other. In other words "Does a specific form of process parameterization emerge for a specific model given its system architecture and data while no or little assumption has been made about the process parameterization itself? In this study we relax the assumption regarding a specific pre-determined form for the process parameterizations of a rainfall/runoff model and examine how varying the complexity of the system architecture can lead to different or possibly contradictory parameterization forms than what would have been decided otherwise. This comparison implicitly and explicitly provides us with an assessment of how uncertain is our perception of model process parameterization in respect to the extent the data can support.
1. Exploring Alternative Parameterizations for Snowfall with Validation from Satellite and Terrestrial Radars
NASA Technical Reports Server (NTRS)
Molthan, Andrew L.; Petersen, Walter A.; Case, Jonathan L.; Dembek, Scott R.
2009-01-01
CloudSat reflectivity is performed by adopting the discrete-dipole parameterizations and databases provided in literature, and demonstrate an improved capability in simulating radar reflectivity at W-band versus Mie scattering assumptions.
2. Meshless thin-shell simulation based on global conformal parameterization.
PubMed
Guo, Xiaohu; Li, Xin; Bao, Yunfan; Gu, Xianfeng; Qin, Hong
2006-01-01
This paper presents a new approach to the physically-based thin-shell simulation of point-sampled geometry via explicit, global conformal point-surface parameterization and meshless dynamics. The point-based global parameterization is founded upon the rigorous mathematics of Riemann surface theory and Hodge theory. The parameterization is globally conformal everywhere except for a minimum number of zero points. Within our parameterization framework, any well-sampled point surface is functionally equivalent to a manifold, enabling popular and powerful surface-based modeling and physically-based simulation tools to be readily adapted for point geometry processing and animation. In addition, we propose a meshless surface computational paradigm in which the partial differential equations (for dynamic physical simulation) can be applied and solved directly over point samples via Moving Least Squares (MLS) shape functions defined on the global parametric domain without explicit connectivity information. The global conformal parameterization provides a common domain to facilitate accurate meshless simulation and efficient discontinuity modeling for complex branching cracks. Through our experiments on thin-shell elastic deformation and fracture simulation, we demonstrate that our integrative method is very natural, and that it has great potential to further broaden the application scope of point-sampled geometry in graphics and relevant fields.
3. Functional parameterization for hydraulic conductivity inversion with uncertainty quantification
Jiao, Jianying; Zhang, Ye
2015-05-01
Functional inversion based on local approximate solutions (LAS) is developed for steady-state flow in heterogeneous aquifers. The method employs a set of LAS of flow to impose spatial continuity of hydraulic head and Darcy fluxes in the solution domain, which are conditioned to limited measurements. Hydraulic conductivity is first parameterized as piecewise continuous, which requires the addition of a smoothness constraint to reduce inversion artifacts. Alternatively, it is formulated as piecewise constant, for which the smoothness constraint is not required, but the data requirement is much higher. Success of the inversion with both parameterizations is demonstrated for both one-dimensional synthetic examples and an oil-field permeability profile. When measurement errors are increased, estimation becomes less accurate but the solution is stable, i.e., estimation errors remain bounded. Compared to piecewise constant parameterization, piecewise continuous parameterization leads to more stable and accurate inversion. Moreover, conductivity variation can also be captured at two spatial scales reflecting sub-facies smooth-varying heterogeneity as well as abrupt changes at facies boundaries. By combining inversion with geostatistical simulation, uncertainty in the estimated conductivity and the hydraulic head field can be quantified. For a given measurement dataset, inversion accuracy and estimation uncertainty with the piecewise continuous parameterization is not sensitive to increasing conductivity contrast.
4. Parameterizing liquid crystal variable retarder structural organization with a fractal-Born approximation model
Gladish, James C.; Duncan, Donald D.
2016-05-01
Liquid crystal variable retarders (LCVRs) are computer-controlled birefringent devices that contain nanometer-sized birefringent liquid crystals (LCs). These devices impart retardance effects through a global, uniform orientation change of the LCs, which is based on a user-defined drive voltage input. In other words, the LC structural organization dictates the device functionality. The LC structural organization also produces a spectral scatter component which exhibits an inverse power law dependence. We investigate LC structural organization by measuring the voltage-dependent LC spectral scattering signature with an integrating sphere and then relate this observable to a fractal-Born model based on the Born approximation and a Von Kármán spectrum. We obtain LCVR light scattering spectra at various drive voltages (i.e., different LC orientations) and then parameterize LCVR structural organization with voltage-dependent correlation lengths. The results can aid in determining performance characteristics of systems using LCVRs and can provide insight into interpreting structural organization measurements.
5. Parameterized reduced-order models using hyper-dual numbers.
SciTech Connect
Fike, Jeffrey A.; Brake, Matthew Robert
2013-10-01
The goal of most computational simulations is to accurately predict the behavior of a real, physical system. Accurate predictions often require very computationally expensive analyses and so reduced order models (ROMs) are commonly used. ROMs aim to reduce the computational cost of the simulations while still providing accurate results by including all of the salient physics of the real system in the ROM. However, real, physical systems often deviate from the idealized models used in simulations due to variations in manufacturing or other factors. One approach to this issue is to create a parameterized model in order to characterize the effect of perturbations from the nominal model on the behavior of the system. This report presents a methodology for developing parameterized ROMs, which is based on Craig-Bampton component mode synthesis and the use of hyper-dual numbers to calculate the derivatives necessary for the parameterization.
6. Baroclinic adjustment. [parameterization of eddy flux effects on atmospheric temperature
NASA Technical Reports Server (NTRS)
Stone, P. H.
1978-01-01
A detailed comparison is presented of the actual shear in the atmosphere with the critical shear given by the two-layer model of Phillips (1954), in which there is a critical temperature gradient separating stable conditions from baroclinically unstable ones. A very simple parameterization of the effect of eddy fluxes on atmospheric temperature is suggested, where the parameterization includes beta effects. The parameterization is illustrated by applying it in a one-dimensional heat-balance climate model. Enhancement of the eddy flux in a continuous atmosphere under supercritical conditions is stressed. This enhancement leads to a negative feedback between the meridional eddy flux of heat and the meridional temperature gradient. The feedback restricts gradients to values near the critical value, a process referred to as baroclinic adjustment. This should facilitate the development of simple climate models involving feedbacks associated with both the meridional vertical temperature structure.
7. Cloud-radiation interactions and their parameterization in climate models
NASA Technical Reports Server (NTRS)
1994-01-01
This report contains papers from the International Workshop on Cloud-Radiation Interactions and Their Parameterization in Climate Models met on 18-20 October 1993 in Camp Springs, Maryland, USA. It was organized by the Joint Working Group on Clouds and Radiation of the International Association of Meteorology and Atmospheric Sciences. Recommendations were grouped into three broad areas: (1) general circulation models (GCMs), (2) satellite studies, and (3) process studies. Each of the panels developed recommendations on the themes of the workshop. Explicitly or implicitly, each panel independently recommended observations of basic cloud microphysical properties (water content, phase, size) on the scales resolved by GCMs. Such observations are necessary to validate cloud parameterizations in GCMs, to use satellite data to infer radiative forcing in the atmosphere and at the earth's surface, and to refine the process models which are used to develop advanced cloud parameterizations.
8. Cloud-radiation interactions and their parameterization in climate models
SciTech Connect
1994-11-01
This report contains papers from the International Workshop on Cloud-Radiation Interactions and Their Parameterization in Climate Models met on 18--20 October 1993 in Camp Springs, Maryland, USA. It was organized by the Joint Working Group on Clouds and Radiation of the International Association of Meteorology and Atmospheric Sciences. Recommendations were grouped into three broad areas: (1) general circulation models (GCMs), (2) satellite studies, and (3) process studies. Each of the panels developed recommendations on the. themes of the workshop. Explicitly or implicitly, each panel independently recommended observations of basic cloud microphysical properties (water content, phase, size) on the scales resolved by GCMs. Such observations are necessary to validate cloud parameterizations in GCMs, to use satellite data to infer radiative forcing in the atmosphere and at the earths surface, and to refine the process models which are used to develop advanced cloud parameterizations.
9. Parameterization of and Brine Storage in MOR Hydrothermal Systems
Hoover, J.; Lowell, R. P.; Cummings, K. B.
2009-12-01
Single-pass parameterized models of high-temperature hydrothermal systems at oceanic spreading centers use observational constraints such as vent temperature, heat output, vent field area, and the area of heat extraction from the sub-axial magma chamber to deduce fundamental hydrothermal parameters such as total mass flux Q, bulk permeability k, and the thickness of the conductive boundary layer at the base of the system, δ. Of the more than 300 known systems, constraining data are available for less than 10%. Here we use the single pass model to estimate Q, k, and δ for all the seafloor hydrothermal systems for which the constraining data are available. Mean values of Q, k, and δ are 170 kg/s, 5.0x10-13 m2, and 20 m, respectively; which is similar to results obtained from the generic model. There is no apparent correlation with spreading rate. Using observed vent field lifetimes, the rate of magma replenishment can also be calculated. Essentially all high-temperature hydrothermal systems at oceanic spreading centers undergo phase separation, yielding a low chlorinity vapor and a high salinity brine. Some systems such as the Main Endeavour Field on the Juan de Fuca Ridge and the 9°50’N sites on the East Pacific Rise vent low chlorinity vapor for many years, while the high density brine remains sequestered beneath the seafloor. In an attempt to further understand the brine storage at the EPR, we used the mass flux Q determined above, time series of vent salinity and temperature, and the depth of the magma chamber to determine the rate of brine production at depth. We found thicknesses ranging from 0.32 meters to ~57 meters over a 1 km2 area from 1994-2002. These calculations suggest that brine maybe being stored within the conductive boundary layer without a need for lateral transport or removal by other means. We plan to use the numerical code FISHES to further test this idea.
10. A New WRF-Chem Treatment for Studying Regional Scale Impacts of Cloud-Aerosol Interactions in Parameterized Cumuli
SciTech Connect
Berg, Larry K.; Shrivastava, ManishKumar B.; Easter, Richard C.; Fast, Jerome D.; Chapman, Elaine G.; Liu, Ying
2015-01-01
A new treatment of cloud-aerosol interactions within parameterized shallow and deep convection has been implemented in WRF-Chem that can be used to better understand the aerosol lifecycle over regional to synoptic scales. The modifications to the model to represent cloud-aerosol interactions include treatment of the cloud dropletnumber mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. Thesechanges have been implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch cumulus parameterization that has been modified to better represent shallow convective clouds. Preliminary testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS) as well as a high-resolution simulation that does not include parameterized convection. The simulation results are used to investigate the impact of cloud-aerosol interactions on the regional scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +35% for sulfate in non-precipitating conditions due to the sulfate production in the parameterized clouds. The modifications to WRF-Chem version 3.2.1 are found to account for changes in the cloud drop number concentration (CDNC) and changes in the chemical composition of cloud-drop residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to WRF-Chem version 3.5, and it is anticipated that they
11. Electromagnetic scattering: applications to atmospheric sciences and beyond
Yang, P.
2015-12-01
Atmospheric particles (cloud droplets, ice crystals and aerosol particles) scatter and absorb solar radiation and thermal infrared emission, and play an important role in the radiation budget in the earth-atmosphere coupled system, and hence are essential to the earth's climate. In this talk I will briefly review electromagnetic scattering research with a focus on applications to atmospheric radiation parameterization and remote sensing. Specifically, I will review state-of-the-art modeling capabilities in computing the single-scattering properties of dielectric particles. Furthermore, I will illustrate some examples of relevant applications.
12. Constraining the Parameterization of Polar Inertia Gravity Waves in WACCM with Observations
Smith, A. K.; Murphy, D. J.; Garcia, R. R.; Kinnison, D. E.
2014-12-01
A discrepancy that has been seen in a number of climate models is that simulated temperatures in the Antarctic lower stratosphere during winter and spring are much lower than observed; this is referred to as the "cold pole" problem. Recent simulations with the NCAR Whole Atmosphere Community Climate Model have shown that polar stratospheric temperatures are much improved by including a parameterization of gravity waves, which have inertial periods, longer horizontal wavelengths and shorter vertical wavelengths than the mesoscale gravity waves already parameterized in this and most other middle atmosphere models. Improvements include a more realistic seasonal development of the ozone hole and somewhat better timing for the winter to summer transition in the zonal winds and Brewer-Dobson Circulation. Although the availability and quality of observations of gravity waves in the middle atmosphere has been increasing, there are still not sufficient observations to validate the inertial gravity wave morphology and distribution in the model. Here, we use constraints from new analyses of radiosonde observations to provide guidance for the horizontal and vertical wavelengths of the waves, their seasonal variability, and their potential sources such as fronts or flow imbalance. Tighter observational constraints remove an element of arbitrary "tuning" and tie the model simulations of the middle atmosphere more closely to the simulated climate.
13. CLOUD PARAMETERIZATIONS, CLOUD PHYSICS, AND THEIR CONNECTIONS: AN OVERVIEW.
SciTech Connect
LIU,Y.; DAUM,P.H.; CHAI,S.K.; LIU,F.
2002-02-12
This paper consists of three parts. The first part is concerned with the parameterization of cloud microphysics in climate models. We demonstrate the crucial importance of spectral dispersion of the cloud droplet size distribution in determining radiative properties of clouds (e.g., effective radius), and underline the necessity of specifying spectral dispersion in the parameterization of cloud microphysics. It is argued that the inclusion of spectral dispersion makes the issue of cloud parameterization essentially equivalent to that of the droplet size distribution function, bringing cloud parameterization to the forefront of cloud physics. The second part is concerned with theoretical investigations into the spectral shape of droplet size distributions in cloud physics. After briefly reviewing the mainstream theories (including entrainment and mixing theories, and stochastic theories), we discuss their deficiencies and the need for a paradigm shift from reductionist approaches to systems approaches. A systems theory that has recently been formulated by utilizing ideas from statistical physics and information theory is discussed, along with the major results derived from it. It is shown that the systems formalism not only easily explains many puzzles that have been frustrating the mainstream theories, but also reveals such new phenomena as scale-dependence of cloud droplet size distributions. The third part is concerned with the potential applications of the systems theory to the specification of spectral dispersion in terms of predictable variables and scale-dependence under different fluctuating environments.
14. Parameterization of HONO sources in Mega-Cities
Li, Guohui; Zhang, Renyi; Tie, Xuxie; Molina, Luisa
2013-04-01
Nitrous acid (HONO) plays an important role in the photochemistry of the troposphere because the photolysis of HONO is a primary source of the hydroxyl radical (OH) in the early morning. However, the formation or sources of HONO are still poorly understood in the troposphere; hence the representation of the HONO sources in chemical transport models (CTMs) has lack comprehensive consideration. In the present study, the observed HONO, NOx, and aerosols at an urban supersite T0 during the MCMA-2006 field campaign in Mexico City are used to interpret the HONO formation in association with the suggested HONO sources from literature. The HONO source parameterizations are proposed and incorporated into the WRF-CHEM model. Homogeneous sources of HONO include the reaction of NO with OH and excited NO2 with H2O. Four HONO heterogeneous sources are considered: NO2 reaction with semivolatile organics, NO2 reaction with freshly emitted soot, NO2 reaction on aerosol and ground surfaces. Four cases are used in the present study to evaluate the proposed HONO parameterizations during four field campaigns in which HONO measurements are available, including MCMA-2003 and MCMA-2006 (Mexico City Metropolitan Area, Mexico), MIRAGE-2009 (Shanghai, China), and SHARP (Houston, USA). The WRF-CHEM model with the proposed HONO parameterizations performs moderately well in reproducing the observed diurnal variation of HONO concentrations, showing that the HONO parameterizations in the study are reasonable and potentially useful in improving the HONO simulation in CTMs.
15. Parameterization of HONO sources in Mega-Cities
Li, G.; Zhang, R.; Tie, X.; Molina, L. T.
2013-05-01
Nitrous acid (HONO) plays an important role in the photochemistry of the troposphere because the photolysis of HONO is a primary source of the hydroxyl radical (OH) in the early morning. However, the formation or sources of HONO are still poorly understood in the troposphere and thence the representation of the HONO sources in chemical transport models (CTMs) is lack of comprehensive consideration. In the present study, the observed HONO, NOx, and aerosols at an urban supersite T0 during the MCMA-2006 field campaign in Mexico City are used to interpret the HONO formation in association with the suggested HONO sources from literature. The HONO source parameterizations are proposed and incorporated into the WRF-CHEM model. Homogeneous sources of HONO include the reaction of NO with OH and excited NO2 with H2O. Four HONO heterogeneous sources are considered: NO2 reaction with semivolatile organics, NO2 reaction with freshly emitted soot, NO2 reaction on aerosol and ground surfaces. Four cases are used in the present study to evaluate the proposed HONO parameterizations during four field campaigns in which HONO measurements are available, including MCMA-2003 and MCMA-2006 (Mexico City Metropolitan Area, Mexico), MIRAGE-2009 (Shanghai, China), and SHARP (Houston, USA). The WRF-CHEM model with the proposed HONO parameterizations performs moderately well in reproducing the observed diurnal variation of HONO concentrations, showing that the HONO parameterizations in the study are reasonable and potentially useful in improving the HONO simulation in CTMs.
16. Downscaling, parameterization, decomposition, compression: a perspective from the multiresolution analysis
Yano, J.-I.
2010-06-01
Geophysical models in general, and atmospheric models more specifically, are always limited in spatial resolutions. Due to this limitation, we face with two different needs. The first is a need for knowing (or "downscaling") more spatial details (e.g., precipitation distribution) than having model simulations for practical applications, such as hydrological modelling. The second is a need for "parameterizing" the subgrid-scale physical processes in order to represent the feedbacks of these processes on to the resolved scales (e.g., the convective heating rate). The present article begins by remarking that it is essential to consider the downscaling and parametrization as an "inverse" of each other: downscaling seeks a detail of the subgrid-scale processes, then the parameterization seeks an integrated effect of the former into the resolved scales. A consideration on why those two closely-related operations are traditionally treated separately, gives insights of the fundamental limitations of the current downscalings and parameterizations. The multiresolution analysis (such as those based on wavelet) provides an important conceptual framework for developing a unified formulation for the downscaling and parameterization. In the vocabulary of multiresolution analysis, these two operations may be considered as types of decompression and compression. A new type of a subgrid-scale representation scheme, NAM-SCA (nonhydrostatic anelastic model with segmentally-constant approximation), is introduced under this framework.
17. Parameterizing Subgrid Orographic Precipitation and Surface Cover in Climate Models
SciTech Connect
Leung, Lai R.; Ghan, Steven J.
1998-10-01
Previous development of the Pacific Northwest National Laboratory's regional climate model has focused on representing orographic precipitation using a subgrid parameterization where subgrid variations of surface elevation are aggregated to a limited number of elevation classes. An airflow model and a thermodynamic model are used to parameterize the orographic uplift/descent as air parcels cross over mountain barriers or valleys. This paper describes further testing and evaluation of this subgrid parameterization. Building upon this modeling framework, a subgrid vegetation scheme has been developed based on statistical relationships between surface elevation and vegetation. By analyzing high-resolution elevation and vegetation data, a dominant land cover is defined for each elevation band of each model grid cell to account for the subgrid heterogeneity in vegetation. When larger lakes are present, they are distinguished from land within elevation bands and a lake model is used to simulate the thermodynamic properties. The use of the high-resolution vegetation data and the subgrid vegetation scheme has resulted in an improvement in the model's representation of surface cover over the western United States. Simulation using the new vegetation scheme yields a 1 C cooling when compared with a simulation where vegetation was derived from a 30-min global vegetation dataset without subgrid vegetation treatment; this cooling helps to reduce the warm bias previously found in the regional climate model. A 3-yr simulation with the subgrid parameterization in the climate model is compared with observations.
18. IMPLEMENTATION OF AN URBAN CANOPY PARAMETERIZATION IN MM5
EPA Science Inventory
The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) (Grell et al. 1994) has been modified to include an urban canopy parameterization (UCP) for fine-scale urban simulations (~1-km horizontal grid spacing). The UCP accounts for drag ...
19. The Project for Intercomparison of Land-surface Parameterization Schemes
NASA Technical Reports Server (NTRS)
Henderson-Sellers, A.; Yang, Z.-L.; Dickinson, R. E.
1993-01-01
The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) is described and the first stage science plan outlined. PILPS is a project designed to improve the parameterization of the continental surface, especially the hydrological, energy, momentum, and carbon exchanges with the atmosphere. The PILPS Science Plan incorporates enhanced documentation, comparison, and validation of continental surface parameterization schemes by community participation. Potential participants include code developers, code users, and those who can provide datasets for validation and who have expertise of value in this exercise. PILPS is an important activity because existing intercomparisons, although piecemeal, demonstrate that there are significant differences in the formulation of individual processes in the available land surface schemes. These differences are comparable to other recognized differences among current global climate models such as cloud and convection parameterizations. It is also clear that too few sensitivity studies have been undertaken with the result that there is not yet enough information to indicate which simplifications or omissions are important for the near-surface continental climate, hydrology, and biogeochemistry. PILPS emphasizes sensitivity studies with and intercomparisons of existing land surface codes and the development of areally extensive datasets for their testing and validation.
20. Overview of an Urban Canopy Parameterization in COAMPS
SciTech Connect
Leach, M J; Chin, H S
2006-02-09
The Coupled Atmosphere/Ocean Mesoscale Prediction System (COAMPS) model (Hodur, 1997) was developed at the Naval Research Laboratory. COAMPS has been used at resolutions as small as 2 km to study the role of complex topography in generating mesoscale circulation (Doyle, 1997). The model has been adapted for use in the Atmospheric Science Division at LLNL for both research and operational use. The model is a fully, non-hydrostatic model with several options for turbulence parameterization, cloud processes and radiative transfer. We have recently modified the COAMPS code to include building and other urban surfaces effects in the mesoscale model by incorporating an urban canopy parameterization (UCP) (Chin et al., 2005). This UCP is a modification of the original parameterization of (Brown and Williams, 1998), based on Yamada's (1982) forest canopy parameterization and includes modification of the TKE and mean momentum equations, modification of radiative transfer, and an anthropogenic heat source. COAMPS is parallelized for both shared memory (OpenMP) and distributed memory (MPI) architecture.
1. Parameterizations in high resolution isopycanl wind-driven ocean models
SciTech Connect
Jensen, T.G.; Randall, D.A.
1993-01-01
For the CHAMMP project, we proposed to implement and test new numerical schemes, parameterizations of boundary layer flow and development and implement mixed layer physics in an existing isopycnal models. The objectives for the proposed research were; implement the Arakawa and Hsu, scheme in an existing isopycnal model of the Indian Ocean; recode the new model for a highly parallel architecture; determine effects of various parameterizations of islands; determine the correct lateral boundary condition for boundary layer currents, as for instance the Gulf Stream and other western boundary currents.; and incorporate a oceanic mixed layer on top of the isopycnal deep layers. This is, primarily a model development project, with emphasis on determining the influence and parameterization of narrow flows along continents and through chains of small islands on the large scale oceanic circulation, which is resolved by climate models. The new model is based on the multi-layer FSU Indian Ocean model. Our research strategy is to; recode a one-layer version of the Indian Ocean Model for a highly parallel computer; add thermodynamics to a rectangular domain version of the new model; implement the irregular domain from the Indian Ocean Model into the box model; change the numerical scheme for the continuity equation to the scheme proposed by; perform parameterization experiments with various coast line and island geometries. This report discusses project progress for period August 1, 1992 through December 31, 1992.
2. Validation of an Urban Parameterization in a Mesoscale Model
SciTech Connect
Leach, M.J.; Chin, H.
2001-07-19
The Atmospheric Science Division at Lawrence Livermore National Laboratory uses the Naval Research Laboratory's Couple Ocean-Atmosphere Mesoscale Prediction System (COAMPS) for both operations and research. COAMPS is a non-hydrostatic model, designed as a multi-scale simulation system ranging from synoptic down to meso, storm and local terrain scales. As model resolution increases, the forcing due to small-scale complex terrain features including urban structures and surfaces, intensifies. An urban parameterization has been added to the Naval Research Laboratory's mesoscale model, COAMPS. The parameterization attempts to incorporate the effects of buildings and urban surfaces without explicitly resolving them, and includes modeling the mean flow to turbulence energy exchange, radiative transfer, the surface energy budget, and the addition of anthropogenic heat. The Chemical and Biological National Security Program's (CBNP) URBAN field experiment was designed to collect data to validate numerical models over a range of length and time scales. The experiment was conducted in Salt Lake City in October 2000. The scales ranged from circulation around single buildings to flow in the entire Salt Lake basin. Data from the field experiment includes tracer data as well as observations of mean and turbulence atmospheric parameters. Wind and turbulence predictions from COAMPS are used to drive a Lagrangian particle model, the Livermore Operational Dispersion Integrator (LODI). Simulations with COAMPS and LODI are used to test the sensitivity to the urban parameterization. Data from the field experiment, including the tracer data and the atmospheric parameters, are also used to validate the urban parameterization.
3. The role of dataset selection in cloud microphysics parameterization development
Kogan, Y. L.
2009-12-01
A number of cloud microphysical parameterizations have been developed during the last decade using various datasets of cloud drop spectra. These datasets can be obtained either from observations, artificially produced by some drop size spectra generator (e.g. by solving the coagulation equation under different input conditions), or obtained as output of LES model which can predict cloud drop spectra explicitly. Each of the methods has its deficiencies, for example in-situ aircraft observations being constrained to the flight path and the dependence of coagulation equation solutions on input conditions. The ultimate aim is to create a cloud drop spectra dataset that mimics realistically drop parameters in real clouds. These parameters are closely related to the distribution of thermodynamical conditions, which are difficult, if not impossible, to obtain a priori. Using LES model with explicit microphysics (SAMEX) we have demonstrated high sensitivity of cloud parameterizations to the choice of a dataset. We emphasize that the development of accurate parameterizations should require the use of a dynamically balanced cloud drop spectra dataset. The accuracy of conversion rates can be increased by scaling them with precipitation intensity. We also demonstrate that the accuracy of the saturation adjustment scheme employed in calculations of latent heat release can be increased by accounting for the aerosol load. Finally we show how to formulate the new saturation adjustment in the framework of a two-moment cloud physics parameterization.
4. Scattering in Quantum Lattice Gases
O'Hara, Andrew; Love, Peter
2009-03-01
Quantum Lattice Gas Automata (QLGA) are of interest for their use in simulating quantum mechanics on both classical and quantum computers. QLGAs are an extension of classical Lattice Gas Automata where the constraint of unitary evolution is added. In the late 1990s, David A. Meyer as well as Bruce Boghosian and Washington Taylor produced similar models of QLGAs. We start by presenting a unified version of these models and study them from the point of view of the physics of wave-packet scattering. We show that the Meyer and Boghosian-Taylor models are actually the same basic model with slightly different parameterizations and limits. We then implement these models computationally using the Python programming language and show that QLGAs are able to replicate the analytic results of quantum mechanics (for example reflected and transmitted amplitudes for step potentials and the Klein paradox).
5. Climate and cloud response of the Super-Parameterized Community Atmosphere Model with additional super-parameterization of low clouds
Khairoutdinov, Marat
2013-04-01
A multiscale-modeling framework (MMF) is the class of general circulation models (GCMs) in which the effects of unresolved-by-GCM-grid cloud processes are explicitly represented by a cloud-resolving model (CRM), also known as super-parameterization (SP), inserted into each column of the GCM grid. Traditionally, due to high computational cost, the SP in MMFs has usually been configured to run with grid spacings that are, in general, barely sufficient to represent deep and extensive convective systems. As the result, the effects of small shallow clouds and, to a lesser extent, mid-level clouds in MMFs have generally been underestimated. The situation is particularly aggravated by the notion that the shallow low clouds are believed to have particularly important feedbacks in the Earth's climate system. A simple decrease of horizontal grid spacing from a few kilometers to a few hundred meters keeping the domain size unchanged is prohibitive as it would increase the already high computational cost of running the MMF by about a factor of a hundred. One of the solutions, which is currently being explored by various modeling groups, is to use some sophisticated higher-order parameterization of shallow clouds; however, the whole premise of super-parameterization has been to minimize parameterization of cloud dynamics as much as possible under assumption that cloud feedbacks are better represented by the dynamically and physically consistent CRMs rather than by parameterizations based, for example, on the entraining-plume model. In this study, several global climate simulations are performed using the super-parameterized Community Atmosphere Model (SP-CAM) that employs an additional super-parameterization nicknamed (perhaps misleading) as MiniLES, to better represent the low-level shallow clouds with the horizontal grid spacing of a few hundred meters. In particular, the SP-CAM/MiniLES MMF seems to significantly improve the simulation of the observed low-cloud global
6. A Comparison of Parameterizations of Secondary Organic Aerosol Production: Global Budget and Spatiotemporal Variability
Liu, J.; Chen, Z.; Horowitz, L. W.; Carlton, A. M. G.; Fan, S.; Cheng, Y.; Ervens, B.; Fu, T. M.; He, C.; Tao, S.
2014-12-01
Secondary organic aerosols (SOA) have a profound influence on air quality and climate, but large uncertainties exist in modeling SOA on the global scale. In this study, five SOA parameterization schemes, including a two-product model (TPM), volatility basis-set (VBS) and three cloud SOA schemes (Ervens et al. (2008, 2014), Fu et al. (2008) , and He et al. (2013)), are implemented into the global chemical transport model (MOZART-4). For each scheme, model simulations are conducted with identical boundary and initial conditions. The VBS scheme produces the highest global annual SOA production (close to 35 Tg·y-1), followed by three cloud schemes (26-30 Tg·y-1) and TPM (23 Tg·y-1). Though sharing a similar partitioning theory to the TPM scheme, the VBS approach simulates the chemical aging of multiple generations of VOCs oxidation products, resulting in a much larger SOA source, particularly from aromatic species, over Europe, the Middle East and Eastern America. The formation of SOA in VBS, which represents the net partitioning of semi-volatile organic compounds from vapor to condensed phase, is highly sensitivity to the aging and wet removal processes of vapor-phase organic compounds. The production of SOA from cloud processes (SOAcld) is constrained by the coincidence of liquid cloud water and water-soluble organic compounds. Therefore, all cloud schemes resolve a fairly similar spatial pattern over the tropical and the mid-latitude continents. The spatiotemporal diversity among SOA parameterizations is largely driven by differences in precursor inputs. Therefore, a deeper understanding of the evolution, wet removal, and phase partitioning of semi-volatile organic compounds, particularly above remote land and oceanic areas, is critical to better constrain the global-scale distribution and related climate forcing of secondary organic aerosols.
7. Incorporating an advanced aerosol activation parameterization into WRF-CAM5: Model evaluation and parameterization intercomparison
SciTech Connect
Zhang, Yang; Zhang, Xin; Wang, Kai; He, Jian; Leung, Lai-Yung R.; Fan, Jiwen; Nenes, Athanasios
2015-07-22
Aerosol activation into cloud droplets is an important process that governs aerosol indirect effects. The advanced treatment of aerosol activation by Fountoukis and Nenes (2005) and its recent updates, collectively called the FN series, have been incorporated into a newly developed regional coupled climate-air quality model based on the Weather Research and Forecasting model with the physics package of the Community Atmosphere Model version 5 (WRF-CAM5) to simulate aerosol-cloud interactions in both resolved and convective clouds. The model is applied to East Asia for two full years of 2005 and 2010. A comprehensive model evaluation is performed for model predictions of meteorological, radiative, and cloud variables, chemical concentrations, and column mass abundances against satellite data and surface observations from air quality monitoring sites across East Asia. The model performs overall well for major meteorological variables including near-surface temperature, specific humidity, wind speed, precipitation, cloud fraction, precipitable water, downward shortwave and longwave radiation, and column mass abundances of CO, SO2, NO2, HCHO, and O3 in terms of both magnitudes and spatial distributions. Larger biases exist in the predictions of surface concentrations of CO and NOx at all sites and SO2, O3, PM2.5, and PM10 concentrations at some sites, aerosol optical depth, cloud condensation nuclei over ocean, cloud droplet number concentration (CDNC), cloud liquid and ice water path, and cloud optical thickness. Compared with the default Abdul-Razzack Ghan (2000) parameterization, simulations with the FN series produce ~107–113% higher CDNC, with half of the difference attributable to the higher aerosol activation fraction by the FN series and the remaining half due to feedbacks in subsequent cloud microphysical processes. With the higher CDNC, the FN series are more skillful in simulating cloud water path, cloud optical thickness, downward shortwave radiation
8. Incorporating an advanced aerosol activation parameterization into WRF-CAM5: Model evaluation and parameterization intercomparison
Zhang, Yang; Zhang, Xin; Wang, Kai; He, Jian; Leung, L. Ruby; Fan, Jiwen; Nenes, Athanasios
2015-07-01
Aerosol activation into cloud droplets is an important process that governs aerosol indirect effects. The advanced treatment of aerosol activation by Fountoukis and Nenes (2005) and its recent updates, collectively called the FN series, have been incorporated into a newly developed regional coupled climate-air quality model based on the Weather Research and Forecasting model with the physics package of the Community Atmosphere Model version 5 (WRF-CAM5) to simulate aerosol-cloud interactions in both resolved and convective clouds. The model is applied to East Asia for two full years of 2005 and 2010. A comprehensive model evaluation is performed for model predictions of meteorological, radiative, and cloud variables, chemical concentrations, and column mass abundances against satellite data and surface observations from air quality monitoring sites across East Asia. The model performs overall well for major meteorological variables including near-surface temperature, specific humidity, wind speed, precipitation, cloud fraction, precipitable water, downward shortwave and longwave radiation, and column mass abundances of CO, SO2, NO2, HCHO, and O3 in terms of both magnitudes and spatial distributions. Larger biases exist in the predictions of surface concentrations of CO and NOx at all sites and SO2, O3, PM2.5, and PM10 concentrations at some sites, aerosol optical depth, cloud condensation nuclei over ocean, cloud droplet number concentration (CDNC), cloud liquid and ice water path, and cloud optical thickness. Compared with the default Abdul-Razzack Ghan (2000) parameterization, simulations with the FN series produce ~107-113% higher CDNC, with half of the difference attributable to the higher aerosol activation fraction by the FN series and the remaining half due to feedbacks in subsequent cloud microphysical processes. With the higher CDNC, the FN series are more skillful in simulating cloud water path, cloud optical thickness, downward shortwave radiation
9. Stochastic parameterization for light absorption by internally mixed BC/dust in snow grains for application to climate models
Liou, K. N.; Takano, Y.; He, C.; Yang, P.; Leung, L. R.; Gu, Y.; Lee, W. L.
2014-06-01
A stochastic approach has been developed to model the positions of BC (black carbon)/dust internally mixed with two snow grain types: hexagonal plate/column (convex) and Koch snowflake (concave). Subsequently, light absorption and scattering analysis can be followed by means of an improved geometric-optics approach coupled with Monte Carlo photon tracing to determine BC/dust single-scattering properties. For a given shape (plate, Koch snowflake, spheroid, or sphere), the action of internal mixing absorbs substantially more light than external mixing. The snow grain shape effect on absorption is relatively small, but its effect on asymmetry factor is substantial. Due to a greater probability of intercepting photons, multiple inclusions of BC/dust exhibit a larger absorption than an equal-volume single inclusion. The spectral absorption (0.2-5 µm) for snow grains internally mixed with BC/dust is confined to wavelengths shorter than about 1.4 µm, beyond which ice absorption predominates. Based on the single-scattering properties determined from stochastic and light absorption parameterizations and using the adding/doubling method for spectral radiative transfer, we find that internal mixing reduces snow albedo substantially more than external mixing and that the snow grain shape plays a critical role in snow albedo calculations through its forward scattering strength. Also, multiple inclusion of BC/dust significantly reduces snow albedo as compared to an equal-volume single sphere. For application to land/snow models, we propose a two-layer spectral snow parameterization involving contaminated fresh snow on top of old snow for investigating and understanding the climatic impact of multiple BC/dust internal mixing associated with snow grain metamorphism, particularly over mountain/snow topography.
10. Parameterization of mixed layer eddies. III: Implementation and impact in global ocean climate simulations
Fox-Kemper, B.; Danabasoglu, G.; Ferrari, R.; Griffies, S. M.; Hallberg, R. W.; Holland, M. M.; Maltrud, M. E.; Peacock, S.; Samuels, B. L.
A parameterization for the restratification by finite-amplitude, submesoscale, mixed layer eddies, formulated as an overturning streamfunction, has been recently proposed to approximate eddy fluxes of density and other tracers. Here, the technicalities of implementing the parameterization in the coarse-resolution ocean component of global climate models are made explicit, and the primary impacts on model solutions of implementing the parameterization are discussed. Three global ocean general circulation models including this parameterization are contrasted with control simulations lacking the parameterization. The MLE parameterization behaves as expected and fairly consistently in models differing in discretization, boundary layer mixing, resolution, and other parameterizations. The primary impact of the parameterization is a shoaling of the mixed layer, with the largest effect in polar winter regions. Secondary impacts include strengthening the Atlantic meridional overturning while reducing its variability, reducing CFC and tracer ventilation, modest changes to sea surface temperature and air-sea fluxes, and an apparent reduction of sea ice basal melting.
11. Sensitivity analysis of volume scattering phase functions.
PubMed
Tuchow, Noah; Broughton, Jennifer; Kudela, Raphael
2016-08-01
To solve the radiative transfer equation and relate inherent optical properties (IOPs) to apparent optical properties (AOPs), knowledge of the volume scattering phase function is required. Due to the difficulty of measuring the phase function, it is frequently approximated. We explore the sensitivity of derived AOPs to the phase function parameterization, and compare measured and modeled values of both the AOPs and estimated phase functions using data from Monterey Bay, California during an extreme "red tide" bloom event. Using in situ measurements of absorption and attenuation coefficients, as well as two sets of measurements of the volume scattering function (VSF), we compared output from the Hydrolight radiative transfer model to direct measurements. We found that several common assumptions used in parameterizing the radiative transfer model consistently introduced overestimates of modeled versus measured remote-sensing reflectance values. Phase functions from VSF data derived from measurements at multiple wavelengths and a single scattering single angle significantly overestimated reflectances when using the manufacturer-supplied corrections, but were substantially improved using newly published corrections; phase functions calculated from VSF measurements using three angles and three wavelengths and processed using manufacture-supplied corrections were comparable, demonstrating that reasonable predictions can be made using two commercially available instruments. While other studies have reached similar conclusions, our work extends the analysis to coastal waters dominated by an extreme algal bloom with surface chlorophyll concentrations in excess of 100 mg m-3. PMID:27505819
12. Parameterizing Coefficients of a POD-Based Dynamical System
NASA Technical Reports Server (NTRS)
Kalb, Virginia L.
2010-01-01
A method of parameterizing the coefficients of a dynamical system based of a proper orthogonal decomposition (POD) representing the flow dynamics of a viscous fluid has been introduced. (A brief description of POD is presented in the immediately preceding article.) The present parameterization method is intended to enable construction of the dynamical system to accurately represent the temporal evolution of the flow dynamics over a range of Reynolds numbers. The need for this or a similar method arises as follows: A procedure that includes direct numerical simulation followed by POD, followed by Galerkin projection to a dynamical system has been proven to enable representation of flow dynamics by a low-dimensional model at the Reynolds number of the simulation. However, a more difficult task is to obtain models that are valid over a range of Reynolds numbers. Extrapolation of low-dimensional models by use of straightforward Reynolds-number-based parameter continuation has proven to be inadequate for successful prediction of flows. A key part of the problem of constructing a dynamical system to accurately represent the temporal evolution of the flow dynamics over a range of Reynolds numbers is the problem of understanding and providing for the variation of the coefficients of the dynamical system with the Reynolds number. Prior methods do not enable capture of temporal dynamics over ranges of Reynolds numbers in low-dimensional models, and are not even satisfactory when large numbers of modes are used. The basic idea of the present method is to solve the problem through a suitable parameterization of the coefficients of the dynamical system. The parameterization computations involve utilization of the transfer of kinetic energy between modes as a function of Reynolds number. The thus-parameterized dynamical system accurately predicts the flow dynamics and is applicable to a range of flow problems in the dynamical regime around the Hopf bifurcation. Parameter
13. Parameterization of oceanic whitecap fraction based on satellite observations
Albert, M. F. M. A.; Anguelova, M. D.; Manders, A. M. M.; Schaap, M.; de Leeuw, G.
2015-08-01
In this study the utility of satellite-based whitecap fraction (W) values for the prediction of sea spray aerosol (SSA) emission rates is explored. More specifically, the study is aimed at improving the accuracy of the sea spray source function (SSSF) derived by using the whitecap method through the reduction of the uncertainties in the parameterization of W by better accounting for its natural variability. The starting point is a dataset containing W data, together with matching environmental and statistical data, for 2006. Whitecap fraction W was estimated from observations of the ocean surface brightness temperature TB by satellite-borne radiometers at two frequencies (10 and 37 GHz). A global scale assessment of the data set to evaluate the wind speed dependence of W revealed a quadratic correlation between W and U10, as well as a relatively larger spread in the 37 GHz data set. The latter could be attributed to secondary factors affecting W in addition to U10. To better visualize these secondary factors, a regional scale assessment over different seasons was performed. This assessment indicates that the influence of secondary factors on W is for the largest part imbedded in the exponent of the wind speed dependence. Hence no further improvement can be expected by looking at effects of other factors on the variation in W explicitly. From the regional analysis, a new globally applicable quadratic W(U10) parameterization was derived. An intrinsic correlation between W and U10 that could have been introduced while estimating W from TB was determined, evaluated and presumed to lie within the error margins of the newly derived W(U10) parameterization. The satellite-based parameterization was compared to parameterizations from other studies and was applied in a SSSF to estimate the global SSA emission rate. The thus obtained SSA production for 2006 of 4.1 × 1012 kg is within previously reported estimates. While recent studies that account for parameters other than U
14. Budget Comparison of Parameterized Microphysical Processes in Tropical Cyclone Simulations
Michelson, Sara A.; Bao, Jian-Wen; Grell, Evelyn D.
2015-04-01
Despite the fact that microphysics parameterization schemes used in numerical models for tropical cyclone (TC) prediction can be as complex as being capable of resolving the evolution of hydrometeor size spectra, operational centers still cannot computationally afford to run any TC prediction models with spectrum-resolving schemes operationally. To strike an optimal balance between computational cost and physical effect, there is a need to understand what minimal complexity of microphysics parameterizations is required in operational TC prediction models that are run at affordable resolutions. In order to address this need, we have been investigating whether or not the microphysics schemes currently used in NOAA's operational TC models are complex enough to enable us to use these models for high-resolution prediction of tropical cyclones. In this study, we used the Weather Research and Forecasting (WRF) model to investigate the impact of parameterized warm-rain processes in four widely-used bulk microphysics parameterization schemes on the model-simulated tropical cyclone (TC) development. The schemes investigated, ranging from a single-moment simple 3-category scheme to a complex double-moment 6-category scheme, produce different TC intensification rates and average vertical hydrometeor distributions, as well as different accumulated precipitation. By diagnosing the source and sink terms of the hydrometeor budget equations, we found that the differences in the warm-rain production rate, particularly by conversion of cloud water to rain water, contribute significantly to the variations in the frozen hydrometeor production and in the overall latent heat release above the freezing level. These differences in parameterized warm-rain production reflect the differences of the four schemes in the definition of rain droplet size distribution and consequently in spectrum-dependent microphysical processes, such as accretion growth of frozen hydrometeors and their
15. Error in Radar-Derived Soil Moisture due to Roughness Parameterization: An Analysis Based on Synthetical Surface Profiles.
PubMed
Lievens, Hans; Vernieuwe, Hilde; Alvarez-Mozos, Jesús; De Baets, Bernard; Verhoest, Niko E C
2009-01-01
In the past decades, many studies on soil moisture retrieval from SAR demonstrated a poor correlation between the top layer soil moisture content and observed backscatter coefficients, which mainly has been attributed to difficulties involved in the parameterization of surface roughness. The present paper describes a theoretical study, performed on synthetical surface profiles, which investigates how errors on roughness parameters are introduced by standard measurement techniques, and how they will propagate through the commonly used Integral Equation Model (IEM) into a corresponding soil moisture retrieval error for some of the currently most used SAR configurations. Key aspects influencing the error on the roughness parameterization and consequently on soil moisture retrieval are: the length of the surface profile, the number of profile measurements, the horizontal and vertical accuracy of profile measurements and the removal of trends along profiles. Moreover, it is found that soil moisture retrieval with C-band configuration generally is less sensitive to inaccuracies in roughness parameterization than retrieval with L-band configuration.
16. An intracloud lightning parameterization scheme for a storm electrification model
NASA Technical Reports Server (NTRS)
Helsdon, John H., Jr.; Wu, Gang; Farley, Richard D.
1992-01-01
The parameterization of an intracloud lightning discharge has been implemented in the present storm electrification model. The initiation, propagation direction, and termination of the discharge are computed using the magnitude and direction of the electric field vector as the determining criteria. The charge redistribution due to the lightning is approximated assuming the channel to be an isolated conductor with zero net charge over its entire length. Various simulations involving differing amounts of charge transferred and distribution of charges have been done. Values of charge transfer, dipole moment change, and electrical energy dissipation computed in the model are consistent with observations. The effects of the lightning-produced ions on the hydrometeor charges and electric field components depend strongly on the amount of charge transferred. A comparison between the measured electric field change of an actual intracloud flash and the field change due to the simulated discharge shows favorable agreement. Limitations of the parameterization scheme are discussed.
17. A parameterization of effective soil temperature for microwave emission
NASA Technical Reports Server (NTRS)
Choudhury, B. J.; Schmugge, T. J.; Mo, T. (Principal Investigator)
1981-01-01
A parameterization of effective soil temperature is discussed, which when multiplied by the emissivity gives the brightness temperature in terms of surface (T sub o) and deep (T sub infinity) soil temperatures as T = T sub infinity + C (T sub o - T sub infinity). A coherent radiative transfer model and a large data base of observed soil moisture and temperature profiles are used to calculate the best-fit value of the parameter C. For 2.8, 6.0, 11.0, 21.0 and 49.0 cm wavelengths. The C values are respectively 0.802 + or - 0.006, 0.667 + or - 0.008, 0.480 + or - 0.010, 0.246 + or - 0.009, and 0,084 + or - 0.005. The parameterized equation gives results which are generally within one or two percent of the exact values.
18. Parameterization of Model Validating Sets for Uncertainty Bound Optimizations. Revised
NASA Technical Reports Server (NTRS)
Lim, K. B.; Giesy, D. P.
2000-01-01
Given measurement data, a nominal model and a linear fractional transformation uncertainty structure with an allowance on unknown but bounded exogenous disturbances, easily computable tests for the existence of a model validating uncertainty set are given. Under mild conditions, these tests are necessary and sufficient for the case of complex, nonrepeated, block-diagonal structure. For the more general case which includes repeated and/or real scalar uncertainties, the tests are only necessary but become sufficient if a collinearity condition is also satisfied. With the satisfaction of these tests, it is shown that a parameterization of all model validating sets of plant models is possible. The new parameterization is used as a basis for a systematic way to construct or perform uncertainty tradeoff with model validating uncertainty sets which have specific linear fractional transformation structure for use in robust control design and analysis. An illustrative example which includes a comparison of candidate model validating sets is given.
19. Parameterized neural networks for high-energy physics
Baldi, Pierre; Cranmer, Kyle; Faucett, Taylor; Sadowski, Peter; Whiteson, Daniel
2016-05-01
We investigate a new structure for machine learning classifiers built with neural networks and applied to problems in high-energy physics by expanding the inputs to include not only measured features but also physics parameters. The physics parameters represent a smoothly varying learning task, and the resulting parameterized classifier can smoothly interpolate between them and replace sets of classifiers trained at individual values. This simplifies the training process and gives improved performance at intermediate values, even for complex problems requiring deep learning. Applications include tools parameterized in terms of theoretical model parameters, such as the mass of a particle, which allow for a single network to provide improved discrimination across a range of masses. This concept is simple to implement and allows for optimized interpolatable results.
20. Parameterization of an Active Thermal Erosion Site, Caribou Creek, Alaska
Busey, R.; Bolton, W. R.; Cherry, J. E.; Hinzman, L. D.
2012-12-01
Thermokarst features are thought to be an important mechanism for landscape change in permafrost-dominated cold regions, but few such features have been incorporated into full featured landscape models. The root of this shortcoming is that historic observations are not detailed enough to parameterize a model, and the models typically do not include the relevant processes for thermal erosion. A new, dynamic thermokarst feature has been identified at the Caribou-Poker Creek Research Watershed (CPCRW) in the boreal forest of Interior Alaska. Located adjacent to a traditional use trail, this feature terminates directly in Caribou Creek. Erosion within the feature is driven predominantly by fluvial interflow. CPCRW is a Long-Term Ecological Research site underlain by varying degrees of relatively warm, discontinuous permafrost. This poster will describe the suite of measurements that have been undertaken to parameterize the ERODE model for this site, including thorough surveys, time lapse- and aerial photography, and 3-D structure from motion algorithms.
1. IR OPTICS MEASUREMENT WITH LINEAR COUPLING'S ACTION-ANGLE PARAMETERIZATION.
SciTech Connect
LUO, Y.; BAI, M.; PILAT, R.; SATOGATA, T.; TRBOJEVIC, D.
2005-05-16
A parameterization of linear coupling in action-angle coordinates is convenient for analytical calculations and interpretation of turn-by-turn (TBT) beam position monitor (BPM) data. We demonstrate how to use this parameterization to extract the twiss and coupling parameters in interaction regions (IRs), using BPMs on each side of the long IR drift region. The example of TBT BPM analysis was acquired at the Relativistic Heavy Ion Collider (RHIC), using an AC dipole to excite a single eigenmode. Besides the full treatment, a fast estimate of beta*, the beta function at the interaction point (IP), is provided, along with the phase advance between these BPMs. We also calculate and measure the waist of the beta function and the local optics.
2. On Parameterization of the Global Electric Circuit Generators
Slyunyaev, N. N.; Zhidkov, A. A.
2016-08-01
We consider the problem of generator parameterization in the global electric circuit (GEC) models. The relationship between the charge density and external current density distributions inside a thundercloud is studied using a one-dimensional description and a three-dimensional GEC model. It is shown that drastic conductivity variations in the vicinity of the cloud boundaries have a significant impact on the structure of the charge distribution inside the cloud. Certain restrictions on the charge density distribution in a realistic thunderstorm are found. The possibility to allow for conductivity inhomogeneities in the thunderstorm regions by introducing an effective external current density is demonstrated. Replacement of realistic thunderstorms with equivalent current dipoles in the GEC models is substantiated, an equation for the equivalent current is obtained, and the applicability range of this equation is analyzed. Relationships between the main GEC characteristics under variable parameterization of GEC generators are discussed.
3. Improved CART Data Products and 6cmm Parameterization for Clouds
SciTech Connect
Kenneth Sassen
2004-08-23
Reviewed here is the history of the participation in the Atmospheric Radiation Measurement (ARM) Program, with particular emphasis on research performed between 1999 and 2002, before the PI moved from the University of Utah to the University of Alaska, Fairbanks. The research results are divided into the following areas: IOP research, remote sensing algorithm development using datasets and models, cirrus cloud and SCM/GCM parameterizations, student training, and publications.
4. Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies
Williams, Paul; Howe, Nicola; Gregory, Jonathan; Smith, Robin; Joshi, Manoj
2016-04-01
In climate simulations, the impacts of the sub-grid scales on the resolved scales are conventionally represented using deterministic closure schemes, which assume that the impacts are uniquely determined by the resolved scales. Stochastic parameterization relaxes this assumption, by sampling the sub-grid variability in a computationally inexpensive manner. This presentation shows that the simulated climatological state of the ocean is improved in many respects by implementing a simple stochastic parameterization of ocean eddies into a coupled atmosphere-ocean general circulation model. Simulations from a high-resolution, eddy-permitting ocean model are used to calculate the eddy statistics needed to inject realistic stochastic noise into a low-resolution, non-eddy-permitting version of the same model. A suite of four stochastic experiments is then run to test the sensitivity of the simulated climate to the noise definition, by varying the noise amplitude and decorrelation time within reasonable limits. The addition of zero-mean noise to the ocean temperature tendency is found to have a non-zero effect on the mean climate. Specifically, in terms of the ocean temperature and salinity fields both at the surface and at depth, the noise reduces many of the biases in the low-resolution model and causes it to more closely resemble the high-resolution model. The variability of the strength of the global ocean thermohaline circulation is also improved. It is concluded that stochastic ocean perturbations can yield reductions in climate model error that are comparable to those obtained by refining the resolution, but without the increased computational cost. Therefore, stochastic parameterizations of ocean eddies have the potential to significantly improve climate simulations. Reference PD Williams, NJ Howe, JM Gregory, RS Smith, and MM Joshi (2016) Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies. Journal of Climate, under revision.
5. Parameterization of wind farms in COSMO-LM
Stuetz, E.; Steinfeld, G.; Heinemann, D.; Peinke, J.
2012-04-01
In order to examine the impact of wind farms in the meso scale using numerical simulations parameterizations of wind farms were implemented in a mesoscale model. In 2008/2009 the first wind farm in the german exclusive economic zone - Alpha Ventus - was built. Since then more wind farms are erected in the german exclusive economic zone. Wind farms with up to 80 wind turbines and on an area up to 66 square kilometers are planned - partly only few kilometers apart from one another. Such large wind farms influence the properties of the atmospheric boundary layer at the meso scale by a reduction of the wind speed, a enhancement of the turbulent kinetic energy, but also an alternation of the wind direction. Results of models for the calculation of wakes (wake models), idealistic mesoscale studies as well as observations show, that wind farms of this size produce wakes, which can expand up to a few 10 kilometers downstream. Mesoscale models provide the possibility to investigate the impact of such large wind farms on the atmospheric flow in a larger area and also to examine the effect of wind farms under different weather conditions. For the numerical simulation the mesoscale model COSMO-LM is used. Because the wind turbines of the wind farm cannot be displayed individually due to the large mesh-grid size, the effects of the wind turbine in a numerical model have to be described with the help of a parameterization. Different parameterizations, including the interpretation of a wind farm as enhanced surface roughness or as an impuls deficit and turbulence source, respectively, are implemented into COSMO. The impact of the different wind farm parameterizations on the simulation of the atmospheric boundary layer are presented. as well as first tests of idealistic simulations of wind farms are presented. For this purpose idealistic runs as well as a case study were performed.
6. Physically admissible parameterization for differential Mueller matrix of uniform media.
PubMed
Devlaminck, Vincent; Terrier, Patrick; Charbois, Jean-Michel
2013-05-01
In this Letter, we address the question of physical validity of differential Mueller matrix. A parameterization of entries of this differential matrix is proposed. It ensures that the generators associated with depolarization terms lead to physical Mueller matrices as for the nondepolarizing terms. A general expression for the depolarizing part of the differential matrix is found and a way to compute the nonlinear relations between the parameters is proposed.
7. A parameterization of the depth of the entrainment zone
NASA Technical Reports Server (NTRS)
Boers, Reinout
1989-01-01
A theory of the parameterization of the entrainment zone depth has been developed based on conservation of energy. This theory suggests that the normalized entrainment zone depth is proportional to the inverse square root of the Richardson number. A comparison of this theory with atmospheric observations indicates excellent agreement. It does not adequately predict the laboratory data, although it improves on parcel theory, which is based on a momentum balance.
8. Data-driven RBE parameterization for helium ion beams.
PubMed
Mairani, A; Magro, G; Dokic, I; Valle, S M; Tessonnier, T; Galm, R; Ciocca, M; Parodi, K; Ferrari, A; Jäkel, O; Haberer, T; Pedroni, P; Böhlen, T T
2016-01-21
Helium ion beams are expected to be available again in the near future for clinical use. A suitable formalism to obtain relative biological effectiveness (RBE) values for treatment planning (TP) studies is needed. In this work we developed a data-driven RBE parameterization based on published in vitro experimental values. The RBE parameterization has been developed within the framework of the linear-quadratic (LQ) model as a function of the helium linear energy transfer (LET), dose and the tissue specific parameter (α/β)ph of the LQ model for the reference radiation. Analytic expressions are provided, derived from the collected database, describing the RBEα = αHe/αph and Rβ = βHe/βph ratios as a function of LET. Calculated RBE values at 2 Gy photon dose and at 10% survival (RBE10) are compared with the experimental ones. Pearson's correlation coefficients were, respectively, 0.85 and 0.84 confirming the soundness of the introduced approach. Moreover, due to the lack of experimental data at low LET, clonogenic experiments have been performed irradiating A549 cell line with (α/β)ph = 5.4 Gy at the entrance of a 56.4 MeV u(-1)He beam at the Heidelberg Ion Beam Therapy Center. The proposed parameterization reproduces the measured cell survival within the experimental uncertainties. A RBE formula, which depends only on dose, LET and (α/β)ph as input parameters is proposed, allowing a straightforward implementation in a TP system.
9. New parameterizations and sensitivities for simple climate models
NASA Technical Reports Server (NTRS)
Graves, Charles E.; Lee, Wan-Ho; North, Gerald R.
1993-01-01
This paper presents a reexamination of the earth radiation budget parameterization of energy balance climate models in light of data collected over the last 12 years. The study consists of three parts: (1) an examination of the infrared terrestrial radiation to space and its relationship to the surface temperature field on time scales from 1 month to 10 years; (2) an examination of the albedo of the earth with special attention to the seasonal cycle of snow and clouds; (3) solutions for the seasonal cycle using the new parameterizations with special attention to changes in sensitivity. While the infrared parameterization is not dramatically different from that used in the past, the albedo in the new data suggest that a stronger latitude dependence be employed. After retuning the diffusion coefficient the simulation results for the present climate generally show only a slight dependence on the new parameters. Also, the sensitivity parameter for the model is still about the same (1.25 C for a 1 percent increase of solar constant) for the linear models and for the nonlinear models that include a seasonal snow line albedo feedback (1.34 C). One interesting feature is that a clear-sky planet with a snow line albedo feedback has a significantly higher sensitivity (2.57 C) due to the absence of smoothing normally occurring in the presence of average cloud cover.
10. UQ-Guided Selection of Physical Parameterizations in Climate Models
Lucas, D. D.; Debusschere, B.; Ghan, S.; Rosa, D.; Bulaevskaya, V.; Anderson, G. J.; Chowdhary, K.; Qian, Y.; Lin, G.; Larson, V. E.; Zhang, G. J.; Randall, D. A.
2015-12-01
Given two or more parameterizations that represent the same physical process in a climate model, scientists are sometimes faced with difficult decisions about which scheme to choose for their simulations and analysis. These decisions are often based on subjective criteria, such as "which scheme is easier to use, is computationally less expensive, or produces results that look better?" Uncertainty quantification (UQ) and model selection methods can be used to objectively rank the performance of different physical parameterizations by increasing the preference for schemes that fit observational data better, while at the same time penalizing schemes that are overly complex or have excessive degrees-of-freedom. Following these principles, we are developing a perturbed-parameter UQ framework to assist in the selection of parameterizations for a climate model. Preliminary results will be presented on the application of the framework to assess the performance of two alternate schemes for simulating tropical deep convection (CLUBB-SILHS and ZM-trigmem) in the U.S. Dept. of Energy's ACME climate model. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, is supported by the DOE Office of Science through the Scientific Discovery Through Advanced Computing (SciDAC), and is released as LLNL-ABS-675799.
11. Synthesis of Entrainment and Detrainment formulations for Convection Parameterizations
Siebesma, P.
2015-12-01
Mixing between convective clouds and its environment, usually parameterized in terms of entrainment and detrainment, are among the most important processes that determine the strength of the climate model sensitivity. This notion has led to a renaissance of research in exploring the mechanisms of these mixing processes and, as a result, to a wide range of seemingly different parameterized formulations. In this study we are aiming to synthesize these results as to offer a solid framework for use in parameterized formulations of convection. Detailed LES analyses in which clouds are subsampled according to their size show that entrainment rates are inversely proportional to the typical cloud radius, in accordance with original entraining plume models. These results can be shown analytically to be consistent with entrainment rate formulations of cloud ensembles that decrease inversely proportional with height, by making only mild assumptions on the shape of the associated cloud size distribution. In addition there are additional dependencies of the entrainment rates on the environmental thermodynamics such as the relative humidity and stability but these are of second order. In contrast detrainment rates do depend to first order on the environmental thermodynamics such as relative humidity and stability. This can be understood by realizing that i) the details of the cloud size distribution do depend on these environmental factors and ii) that detrainment rates have a much stronger dependency on the shape of the cloud size distribution than entrainment rates.
12. A satellite observation test bed for cloud parameterization development
Lebsock, M. D.; Suselj, K.
2015-12-01
We present an observational test-bed of cloud and precipitation properties derived from CloudSat, CALIPSO, and the the A-Train. The focus of the test-bed is on marine boundary layer clouds including stratocumulus and cumulus and the transition between these cloud regimes. Test-bed properties include the cloud cover and three dimensional cloud fraction along with the cloud water path and precipitation water content, and associated radiative fluxes. We also include the subgrid scale distribution of cloud and precipitation, and radiaitive quantities, which must be diagnosed by a model parameterization. The test-bed further includes meterological variables from the Modern Era Retrospective-analysis for Research and Applications (MERRA). MERRA variables provide the initialization and forcing datasets to run a parameterization in Single Column Model (SCM) mode. We show comparisons of an Eddy-Diffusivity/Mass-FLux (EDMF) parameterization coupled to micorphsycis and macrophysics packages run in SCM mode with observed clouds. Comparsions are performed regionally in areas of climatological subsidence as well stratified by dynamical and thermodynamical variables. Comparisons demonstrate the ability of the EDMF model to capture the observed transitions between subtropical stratocumulus and cumulus cloud regimes.
13. A parameterization method and application in breast tomosynthesis dosimetry
SciTech Connect
Li, Xinhua; Zhang, Da; Liu, Bob
2013-09-15
Purpose: To present a parameterization method based on singular value decomposition (SVD), and to provide analytical parameterization of the mean glandular dose (MGD) conversion factors from eight references for evaluating breast tomosynthesis dose in the Mammography Quality Standards Act (MQSA) protocol and in the UK, European, and IAEA dosimetry protocols.Methods: MGD conversion factor is usually listed in lookup tables for the factors such as beam quality, breast thickness, breast glandularity, and projection angle. The authors analyzed multiple sets of MGD conversion factors from the Hologic Selenia Dimensions quality control manual and seven previous papers. Each data set was parameterized using a one- to three-dimensional polynomial function of 2–16 terms. Variable substitution was used to improve accuracy. A least-squares fit was conducted using the SVD.Results: The differences between the originally tabulated MGD conversion factors and the results computed using the parameterization algorithms were (a) 0.08%–0.18% on average and 1.31% maximum for the Selenia Dimensions quality control manual, (b) 0.09%–0.66% on average and 2.97% maximum for the published data by Dance et al. [Phys. Med. Biol. 35, 1211–1219 (1990); ibid. 45, 3225–3240 (2000); ibid. 54, 4361–4372 (2009); ibid. 56, 453–471 (2011)], (c) 0.74%–0.99% on average and 3.94% maximum for the published data by Sechopoulos et al. [Med. Phys. 34, 221–232 (2007); J. Appl. Clin. Med. Phys. 9, 161–171 (2008)], and (d) 0.66%–1.33% on average and 2.72% maximum for the published data by Feng and Sechopoulos [Radiology 263, 35–42 (2012)], excluding one sample in (d) that does not follow the trends in the published data table.Conclusions: A flexible parameterization method is presented in this paper, and was applied to breast tomosynthesis dosimetry. The resultant data offer easy and accurate computations of MGD conversion factors for evaluating mean glandular breast dose in the MQSA
14. A stochastic parameterization for deep convection using cellular automata
Bengtsson, L.; Steinheimer, M.; Bechtold, P.; Geleyn, J.
2012-12-01
Cumulus parameterizations used in most operational weather and climate models today are based on the mass-flux concept which took form in the early 1970's. In such schemes it is assumed that a unique relationship exists between the ensemble-average of the sub-grid convection, and the instantaneous state of the atmosphere in a vertical grid box column. However, such a relationship is unlikely to be described by a simple deterministic function (Palmer, 2011). Thus, because of the statistical nature of the parameterization challenge, it has been recognized by the community that it is important to introduce stochastic elements to the parameterizations (for instance: Plant and Craig, 2008, Khouider et al. 2010, Frenkel et al. 2011, Bentsson et al. 2011, but the list is far from exhaustive). There are undoubtedly many ways in which stochastisity can enter new developments. In this study we use a two-way interacting cellular automata (CA), as its intrinsic nature possesses many qualities interesting for deep convection parameterization. In the one-dimensional entraining plume approach, there is no parameterization of horizontal transport of heat, moisture or momentum due to cumulus convection. In reality, mass transport due to gravity waves that propagate in the horizontal can trigger new convection, important for the organization of deep convection (Huang, 1988). The self-organizational characteristics of the CA allows for lateral communication between adjacent NWP model grid-boxes, and temporal memory. Thus the CA scheme used in this study contain three interesting components for representation of cumulus convection, which are not present in the traditional one-dimensional bulk entraining plume method: horizontal communication, memory and stochastisity. The scheme is implemented in the high resolution regional NWP model ALARO, and simulations show enhanced organization of convective activity along squall-lines. Probabilistic evaluation demonstrate an enhanced spread in
15. Stochastic Parameterization for Light Absorption by Internally Mixed BC/dust in Snow Grains for Application to Climate Models
SciTech Connect
Liou, K. N.; Takano, Y.; He, Cenlin; Yang, P.; Leung, Lai-Yung R.; Gu, Y.; Lee, W- L.
2014-06-27
A stochastic approach to model the positions of BC/dust internally mixed with two snow-grain types has been developed, including hexagonal plate/column (convex) and Koch snowflake (concave). Subsequently, light absorption and scattering analysis can be followed by means of an improved geometric-optics approach coupled with Monte Carlo photon tracing to determine their single-scattering properties. For a given shape (plate, Koch snowflake, spheroid, or sphere), internal mixing absorbs more light than external mixing. The snow-grain shape effect on absorption is relatively small, but its effect on the asymmetry factor is substantial. Due to a greater probability of intercepting photons, multiple inclusions of BC/dust exhibit a larger absorption than an equal-volume single inclusion. The spectral absorption (0.2 – 5 um) for snow grains internally mixed with BC/dust is confined to wavelengths shorter than about 1.4 um, beyond which ice absorption predominates. Based on the single-scattering properties determined from stochastic and light absorption parameterizations and using the adding/doubling method for spectral radiative transfer, we find that internal mixing reduces snow albedo more than external mixing and that the snow-grain shape plays a critical role in snow albedo calculations through the asymmetry factor. Also, snow albedo reduces more in the case of multiple inclusion of BC/dust compared to that of an equal-volume single sphere. For application to land/snow models, we propose a two-layer spectral snow parameterization containing contaminated fresh snow on top of old snow for investigating and understanding the climatic impact of multiple BC/dust internal mixing associated with snow grain metamorphism, particularly over mountains/snow topography.
16. Modeling the clouds on Venus: model development and improvement of a nucleation parameterization
Määttänen, Anni; Bekki, Slimane; Vehkamäki, Hanna; Julin, Jan; Montmessin, Franck; Ortega, Ismael K.; Lebonnois, Sébastien
2014-05-01
As both the clouds of Venus and aerosols in the Earth's stratosphere are composed of sulfuric acid droplets, we use the 1-D version of a model [1,4] developed for stratospheric aerosols and clouds to study the clouds on Venus. We have removed processes and compounds related to the stratospheric clouds so that the only species remaining are water and sulfuric acid, corresponding to the stratospheric sulfate aerosols, and we have added some key processes. The model describes microphysical processes including condensation/evaporation, and sedimentation. Coagulation, turbulent diffusion, and a parameterization for two-component nucleation [8] of water and sulfuric acid have been added in the model. Since the model describes explicitly the size distribution with a large number of size bins (50-500), it can handle multiple particle modes. The validity ranges of the existing nucleation parameterization [7] have been improved to cover a larger temperature range, and the very low relative humidity (RH) and high sulfuric acid concentrations found in the atmosphere of Venus. We have made several modifications to improve the 2002 nucleation parameterization [7], most notably ensuring that the two-component nucleation model behaves as predicted by the analytical studies at the one-component limit reached at extremely low RH. We have also chosen to use a self-consistent cluster distribution [9], constrained by scaling it to recent quantum chemistry calculations [3]. First tests of the cloud model have been carried out with temperature profiles from VIRA [2] and from the LMD Venus GCM [5], and with a compilation of water vapor and sulfuric acid profiles, as in [6]. The temperature and pressure profiles do not evolve with time, but the vapour profiles naturally change with the cloud. However, no chemistry is included for the moment, so the vapor concentrations are only dependent on the microphysical processes. The model has been run for several hundreds of Earth days to reach a
17. Tick removal.
PubMed
Roupakias, S; Mitsakou, P; Nimer, A Al
2011-03-01
Ticks are blood feeding external parasites which can cause local and systemic complications to human body. A lot of tick-borne human diseases include Lyme disease and virus encephalitis, can be transmitted by a tick bite. Also secondary bacterial skin infection, reactive manifestations against tick allergens, and granuloma's formation can be occurred. Tick paralysis is a relatively rare complication but it can be fatal. Except the general rules for tick bite prevention, any tick found should be immediately and completely removed alive. Furthermore, the tick removal technique should not allow or provoke the escape of infective body fluids through the tick into the wound site, and disclose any local complication. Many methods of tick removal (a lot of them are unsatisfactory and/or dangerous) have been reported in the literature, but there is very limited experimental evidence to support these methods. No technique will remove completely every tick. So, there is not an appropriate and absolutely effective and/or safe tick removal technique. Regardless of the used tick removal technique, clinicians should be aware of the clinical signs of tick-transmitted diseases, the public should be informed about the risks and the prevention of tick borne diseases, and persons who have undergone tick removal should be monitored up to 30 days for signs and symptoms. PMID:21710824
18. Unsteady polynya flux model solutions incorporating a parameterization for the collection thickness of consolidated new ice
Biggs, Nicholas R. T.; Willmott, Andrew J.
This paper develops a time-dependent, two-dimensional model for the opening of a coastal polynya. The model incorporates a parameterization for the collection thickness of frazil ice at the polynya edge that is given in terms of (a) the depth of frazil ice arriving at the polynya edge, (b) the component normal to the polynya edge of the frazil ice velocity relative to the consolidated new ice velocity, and (c) a constant depth term ( hw) associated with wave radiation stress. The last term depends upon the wavelength of surface waves that are most readily generated by the wind stress, and for coastal polynyas is shown to be of the order of 5 cm. The inclusion of hw also removes possible cases of the parameterization being non-robust in the unsteady problem. Polynya opening solutions are calculated adjacent to a straight coastal barrier of finite length D, by numerically integrating Charpit's equations, a generalisation of the method of characteristics. Polynya opening times are compared with those in a constant collection depth model, when both models open to polynyas with identical steady-state area. For "long" islands ( D≫alongshore adjustment length scale La), the opening time T obeys T> Tc, where Tc is the constant collection depth opening time; when D≪ La, the inequality is reversed. Finally, month by month simulations of the opening of the St. Lawrence Island Polynya (SLIP) are presented, for which satellite-derived steady-state areas are available. In most simulations, the simulated steady-state area falls within the 90% confidence limits of the observed area.
19. eblur/dust: a modular python approach for dust extinction and scattering
Corrales, Lia
2016-03-01
I will present a library of python codes -- github.com/eblur/dust -- which calculate dust scattering and extinction properties from the IR to the X-ray. The modular interface allows for custom defined dust grain size distributions, optical constants, and scattering physics. These codes are currently undergoing a major overhaul to include multiple scattering effects, parallel processing, parameterized grain size distributions beyond power law, and optical constants for different grain compositions. I use eblur/dust primarily to study dust scattering images in the X-ray, but they may be extended to applications at other wavelengths.
20. Data-driven RBE parameterization for helium ion beams
Mairani, A.; Magro, G.; Dokic, I.; Valle, S. M.; Tessonnier, T.; Galm, R.; Ciocca, M.; Parodi, K.; Ferrari, A.; Jäkel, O.; Haberer, T.; Pedroni, P.; Böhlen, T. T.
2016-01-01
Helium ion beams are expected to be available again in the near future for clinical use. A suitable formalism to obtain relative biological effectiveness (RBE) values for treatment planning (TP) studies is needed. In this work we developed a data-driven RBE parameterization based on published in vitro experimental values. The RBE parameterization has been developed within the framework of the linear-quadratic (LQ) model as a function of the helium linear energy transfer (LET), dose and the tissue specific parameter {{(α /β )}\\text{ph}} of the LQ model for the reference radiation. Analytic expressions are provided, derived from the collected database, describing the \\text{RB}{{\\text{E}}α}={α\\text{He}}/{α\\text{ph}} and {{\\text{R}}β}={β\\text{He}}/{β\\text{ph}} ratios as a function of LET. Calculated RBE values at 2 Gy photon dose and at 10% survival (\\text{RB}{{\\text{E}}10} ) are compared with the experimental ones. Pearson’s correlation coefficients were, respectively, 0.85 and 0.84 confirming the soundness of the introduced approach. Moreover, due to the lack of experimental data at low LET, clonogenic experiments have been performed irradiating A549 cell line with {{(α /β )}\\text{ph}}=5.4 Gy at the entrance of a 56.4 MeV u-1He beam at the Heidelberg Ion Beam Therapy Center. The proposed parameterization reproduces the measured cell survival within the experimental uncertainties. A RBE formula, which depends only on dose, LET and {{(α /β )}\\text{ph}} as input parameters is proposed, allowing a straightforward implementation in a TP system.
1. Mechanistic Parameterization of the Kinomic Signal in Peptide Arrays
PubMed Central
Dussaq, Alex; Anderson, Joshua C; Willey, Christopher D; Almeida, Jonas S
2016-01-01
Kinases play a role in every cellular process involved in tumorigenesis ranging from proliferation, migration, and protein synthesis to DNA repair. While genetic sequencing has identified most kinases in the human genome, it does not describe the ‘kinome’ at the level of activity of kinases against their substrate targets. An attempt to address that limitation and give researchers a more direct view of cellular kinase activity is found in the PamGene PamChip® system, which records and compares the phosphorylation of 144 tyrosine or serine/threonine peptides as they are phosphorylated by cellular kinases. Accordingly, the kinetics of this time dependent kinomic signal needs to be well understood in order to transduce a parameter set into an accurate and meaningful mathematical model. Here we report the analysis and mathematical modeling of kinomic time series, which achieves a more accurate description of the accumulation of phosphorylated product than the current model, which assumes first order enzyme-substrate kinetics. Reproducibility of the proposed solution was of particular attention. Specifically, the non-linear parameterization procedure is delivered as a public open source web application where kinomic time series can be accurately decomposed into the model’s two parameter values measuring phosphorylation rate and capacity. The ability to deliver model parameterization entirely as a client side web application is an important result on its own given increasing scientific preoccupation with reproducibility. There is also no need for a potentially transitory and opaque server-side component maintained by the authors, nor of exchanging potentially sensitive data as part of the model parameterization process since the code is transferred to the browser client where it can be inspected and executed.
2. Mechanistic Parameterization of the Kinomic Signal in Peptide Arrays
PubMed Central
Dussaq, Alex; Anderson, Joshua C; Willey, Christopher D; Almeida, Jonas S
2016-01-01
Kinases play a role in every cellular process involved in tumorigenesis ranging from proliferation, migration, and protein synthesis to DNA repair. While genetic sequencing has identified most kinases in the human genome, it does not describe the ‘kinome’ at the level of activity of kinases against their substrate targets. An attempt to address that limitation and give researchers a more direct view of cellular kinase activity is found in the PamGene PamChip® system, which records and compares the phosphorylation of 144 tyrosine or serine/threonine peptides as they are phosphorylated by cellular kinases. Accordingly, the kinetics of this time dependent kinomic signal needs to be well understood in order to transduce a parameter set into an accurate and meaningful mathematical model. Here we report the analysis and mathematical modeling of kinomic time series, which achieves a more accurate description of the accumulation of phosphorylated product than the current model, which assumes first order enzyme-substrate kinetics. Reproducibility of the proposed solution was of particular attention. Specifically, the non-linear parameterization procedure is delivered as a public open source web application where kinomic time series can be accurately decomposed into the model’s two parameter values measuring phosphorylation rate and capacity. The ability to deliver model parameterization entirely as a client side web application is an important result on its own given increasing scientific preoccupation with reproducibility. There is also no need for a potentially transitory and opaque server-side component maintained by the authors, nor of exchanging potentially sensitive data as part of the model parameterization process since the code is transferred to the browser client where it can be inspected and executed. PMID:27601856
3. CCPP-ARM Parameterization Testbed Model Forecast Data
DOE Data Explorer
Klein, Stephen
2008-01-15
Dataset contains the NCAR CAM3 (Collins et al., 2004) and GFDL AM2 (GFDL GAMDT, 2004) forecast data at locations close to the ARM research sites. These data are generated from a series of multi-day forecasts in which both CAM3 and AM2 are initialized at 00Z every day with the ECMWF reanalysis data (ERA-40), for the year 1997 and 2000 and initialized with both the NASA DAO Reanalyses and the NCEP GDAS data for the year 2004. The DOE CCPP-ARM Parameterization Testbed (CAPT) project assesses climate models using numerical weather prediction techniques in conjunction with high quality field measurements (e.g. ARM data).
4. The causal structure of spacetime is a parameterized Randers geometry
Skakala, Jozef; Visser, Matt
2011-03-01
There is a well-established isomorphism between stationary four-dimensional spacetimes and three-dimensional purely spatial Randers geometries—these Randers geometries being a particular case of the more general class of three-dimensional Finsler geometries. We point out that in stably causal spacetimes, by using the (time-dependent) ADM decomposition, this result can be extended to general non-stationary spacetimes—the causal structure (conformal structure) of the full spacetime is completely encoded in a parameterized (t-dependent) class of Randers spaces, which can then be used to define a Fermat principle, and also to reconstruct the null cones and causal structure.
5. Modeling and parameterization of horizontally inhomogeneous cloud radiative properties
NASA Technical Reports Server (NTRS)
Welch, R. M.
1995-01-01
One of the fundamental difficulties in modeling cloud fields is the large variability of cloud optical properties (liquid water content, reflectance, emissivity). The stratocumulus and cirrus clouds, under special consideration for FIRE, exhibit spatial variability on scales of 1 km or less. While it is impractical to model individual cloud elements, the research direction is to model a statistical ensembles of cloud elements with mean-cloud properties specified. The major areas of this investigation are: (1) analysis of cloud field properties; (2) intercomparison of cloud radiative model results with satellite observations; (3) radiative parameterization of cloud fields; and (4) development of improved cloud classification algorithms.
6. Parameterization of interatomic potential by genetic algorithms: A case study
SciTech Connect
Ghosh, Partha S. Arya, A.; Dey, G. K.; Ranawat, Y. S.
2015-06-24
A framework for Genetic Algorithm based methodology is developed to systematically obtain and optimize parameters for interatomic force field functions for MD simulations by fitting to a reference data base. This methodology is applied to the fitting of ThO{sub 2} (CaF{sub 2} prototype) – a representative of ceramic based potential fuel for nuclear applications. The resulting GA optimized parameterization of ThO{sub 2} is able to capture basic structural, mechanical, thermo-physical properties and also describes defect structures within the permissible range.
7. A Parameterized Web-Based Testing Model for Project Management
Bodea, Constanta-Nicoleta; Dascalu, Maria
This paper proposes a web-based testing model for project management. The model is based on ontology for encoding project management knowledge, so it is able to facilitate resource extraction in the web-based testware environment. It also allows generation of parameterized tests, according to the targeted difficulty level. The authors present the theoretical approaches that led to the model: semantic nets and concept space graphs have an important role in model designing. The development of the ontology model is made with SemanticWorks software. The test ontology has applicability in project management certification, especially in those systems with different levels, as the IPMA four-level certification system.
8. Improving Bulk Microphysics Parameterizations in Simulations of Aerosol Effects
SciTech Connect
Wang, Yuan; Fan, Jiwen; Zhang, Renyi; Leung, Lai-Yung R.; Franklin, Charmaine N.
2013-06-05
To improve the microphysical parameterizations for simulations of the aerosol indirect effect (AIE) in regional and global climate models, a double-moment bulk microphysical scheme presently implemented in the Weather Research and Forecasting (WRF) model is modified and the results are compared against atmospheric observations and simulations produced by a spectral bin microphysical scheme (SBM). Rather than using prescribed aerosols as in the original bulk scheme (Bulk-OR), a prognostic doublemoment aerosol representation is introduced to predict both the aerosol number concentration and mass mixing ratio (Bulk-2M). The impacts of the parameterizations of diffusional growth and autoconversion and the selection of the embryonic raindrop radius on the performance of the bulk microphysical scheme are also evaluated. Sensitivity modeling experiments are performed for two distinct cloud regimes, maritime warm stratocumulus clouds (SC) over southeast Pacific Ocean from the VOCALS project and continental deep convective clouds (DCC) in the southeast of China from the Department of Energy/ARM Mobile Facility (DOE/AMF) - China field campaign. The results from Bulk-2M exhibit a much better agreement in the cloud number concentration and effective droplet radius in both the SC and DCC cases with those from SBM and field measurements than those from Bulk-OR. In the SC case particularly, Bulk-2M reproduces the observed drizzle precipitation, which is largely inhibited in Bulk-OR. Bulk-2M predicts enhanced precipitation and invigorated convection with increased aerosol loading in the DCC case, consistent with the SBM simulation, while Bulk-OR predicts the opposite behaviors. Sensitivity experiments using four different types of autoconversion schemes reveal that the autoconversion parameterization is crucial in determining the raindrop number, mass concentration, and drizzle formation for warm 2 stratocumulus clouds. An embryonic raindrop size of 40 μm is determined as a more
9. Tick removal
MedlinePlus
... are small, insect-like creatures that live in woods and fields. They attach to you as you ... your clothes and skin often while in the woods. After returning home: Remove your clothes. Look closely ...
10. Tattoo removal.
PubMed
Adatto, Maurice A; Halachmi, Shlomit; Lapidoth, Moshe
2011-01-01
Over 50,000 new tattoos are placed each year in the United States. Studies estimate that 24% of American college students have tattoos and 10% of male American adults have a tattoo. The rising popularity of tattoos has spurred a corresponding increase in tattoo removal. Not all tattoos are placed intentionally or for aesthetic reasons though. Traumatic tattoos due to unintentional penetration of exogenous pigments can also occur, as well as the placement of medical tattoos to mark treatment boundaries, for example in radiation therapy. Protocols for tattoo removal have evolved over history. The first evidence of tattoo removal attempts was found in Egyptian mummies, dated to have lived 4,000 years BC. Ancient Greek writings describe tattoo removal with salt abrasion or with a paste containing cloves of white garlic mixed with Alexandrian cantharidin. With the advent of Q-switched lasers in the late 1960s, the outcomes of tattoo removal changed radically. In addition to their selective absorption by the pigment, the extremely short pulse duration of Q-switched lasers has made them the gold standard for tattoo removal.
11. Tattoo removal.
PubMed
Adatto, Maurice A; Halachmi, Shlomit; Lapidoth, Moshe
2011-01-01
Over 50,000 new tattoos are placed each year in the United States. Studies estimate that 24% of American college students have tattoos and 10% of male American adults have a tattoo. The rising popularity of tattoos has spurred a corresponding increase in tattoo removal. Not all tattoos are placed intentionally or for aesthetic reasons though. Traumatic tattoos due to unintentional penetration of exogenous pigments can also occur, as well as the placement of medical tattoos to mark treatment boundaries, for example in radiation therapy. Protocols for tattoo removal have evolved over history. The first evidence of tattoo removal attempts was found in Egyptian mummies, dated to have lived 4,000 years BC. Ancient Greek writings describe tattoo removal with salt abrasion or with a paste containing cloves of white garlic mixed with Alexandrian cantharidin. With the advent of Q-switched lasers in the late 1960s, the outcomes of tattoo removal changed radically. In addition to their selective absorption by the pigment, the extremely short pulse duration of Q-switched lasers has made them the gold standard for tattoo removal. PMID:21865802
12. An updated subgrid orographic parameterization for global atmospheric forecast models
Choi, Hyun-Joo; Hong, Song-You
2015-12-01
A subgrid orographic parameterization (SOP) is updated by including the effects of orographic anisotropy and flow-blocking drag (FBD). The impact of the updated SOP on short-range forecasts is investigated using a global atmospheric forecast model applied to a heavy snowfall event over Korea on 4 January 2010. When the SOP is updated, the orographic drag in the lower troposphere noticeably increases owing to the additional FBD over mountainous regions. The enhanced drag directly weakens the excessive wind speed in the low troposphere and indirectly improves the temperature and mass fields over East Asia. In addition, the snowfall overestimation over Korea is improved by the reduced heat fluxes from the surface. The forecast improvements are robust regardless of the horizontal resolution of the model between T126 and T510. The parameterization is statistically evaluated based on the skill of the medium-range forecasts for February 2014. For the medium-range forecasts, the skill improvements of the wind speed and temperature in the low troposphere are observed globally and for East Asia while both positive and negative effects appear indirectly in the middle-upper troposphere. The statistical skill for the precipitation is mostly improved due to the improvements in the synoptic fields. The improvements are also found for seasonal simulation throughout the troposphere and stratosphere during boreal winter.
13. Evaluation of an Urban Canopy Parameterization in a Mesoscale Model
SciTech Connect
Chin, H S; Leach, M J; Sugiyama, G A; Leone, Jr., J M; Walker, H; Nasstrom, J; Brown, M J
2004-03-18
A modified urban canopy parameterization (UCP) is developed and evaluated in a three-dimensional mesoscale model to assess the urban impact on surface and lower atmospheric properties. This parameterization accounts for the effects of building drag, turbulent production, radiation balance, anthropogenic heating, and building rooftop heating/cooling. USGS land-use data are also utilized to derive urban infrastructure and urban surface properties needed for driving the UCP. An intensive observational period with clear-sky, strong ambient wind and drainage flow, and the absence of land-lake breeze over the Salt Lake Valley, occurring on 25-26 October 2000, is selected for this study. A series of sensitivity experiments are performed to gain understanding of the urban impact in the mesoscale model. Results indicate that within the selected urban environment, urban surface characteristics and anthropogenic heating play little role in the formation of the modeled nocturnal urban boundary layer. The rooftop effect appears to be the main contributor to this urban boundary layer. Sensitivity experiments also show that for this weak urban heat island case, the model horizontal grid resolution is important in simulating the elevated inversion layer. The root mean square errors of the predicted wind and temperature with respect to surface station measurements exhibit substantially larger discrepancies at the urban locations than the rural counterparts. However, the close agreement of modeled tracer concentration with observations fairly justifies the modeled urban impact on the wind direction shift and wind drag effects.
14. Comparison of parameterizations for homogeneous and heterogeneous ice nucleation
Koop, T.; Zobrist, B.
2009-04-01
The formation of ice particles from liquid aqueous aerosols is of central importance for the physics and chemistry of high altitude clouds. In this paper, we present new laboratory data on ice nucleation and compare them with two different parameterizations for homogeneous as well as heterogeneous ice nucleation. In particular, we discuss and evaluate the effect of solutes and ice nuclei. One parameterization is the λ-approach which correlates the depression of the freezing temperature of aqueous droplets in comparison to pure water droplets, Tf, with the corresponding depression, Tm, of the equilibrium ice melting point: Tf = λ × Tm. Here, λ is independent of concentration and a constant that is specific for a particular solute or solute/ice nucleus combination. The other approach is water-activity-based ice nucleation theory which describes the effects of solutes on the freezing temperature Tf via their effect on water activity: aw(Tf) = awi(Tf) + aw. Here, awi is the water activity of ice and aw is a constant that depends on the ice nucleus but is independent of the type of solute. We present new data on both homogeneous and heterogeneous ice nucleation with varying types of solutes and ice nuclei. We evaluate and discuss the advantages and limitations of the two approaches for the prediction of ice nucleation in laboratory experiments and atmospheric cloud models.
15. A Parameterization for the Triggering of Landscape Generated Moist Convection
NASA Technical Reports Server (NTRS)
Lynn, Barry H.; Tao, Wei-Kuo; Abramopoulos, Frank
1998-01-01
A set of relatively high resolution three-dimensional (3D) simulations were produced to investigate the triggering of moist convection by landscape generated mesoscale circulations. The local accumulated rainfall varied monotonically (linearly) with the size of individual landscape patches, demonstrating the need to develop a trigger function that is sensitive to the size of individual patches. A new triggering function that includes the effect of landscapes generated mesoscale circulations over patches of different sizes consists of a parcel's perturbation in vertical velocity (nu(sub 0)), temperature (theta(sub 0)), and moisture (q(sub 0)). Each variable in the triggering function was also sensitive to soil moisture gradients, atmospheric initial conditions, and moist processes. The parcel's vertical velocity, temperature, and moisture perturbation were partitioned into mesoscale and turbulent components. Budget equations were derived for theta(sub 0) and q(sub 0). Of the many terms in this set of budget equations, the turbulent, vertical flux of the mesoscale temperature and moisture contributed most to the triggering of moist convection through the impact of these fluxes on the parcel's temperature and moisture profile. These fluxes needed to be parameterized to obtain theta(sub 0) and q(sub 0). The mesoscale vertical velocity also affected the profile of nu(sub 0). We used similarity theory to parameterize these fluxes as well as the parcel's mesoscale vertical velocity.
16. Parameterization of Vegetation Aerodynamic Roughness of Natural Regions Satellite Imagery
NASA Technical Reports Server (NTRS)
Jasinski, Michael F.; Crago, Richard; Stewart, Pamela
1998-01-01
Parameterizations of the frontal area index and canopy area index of natural or randomly distributed plants are developed, and applied to the estimation of local aerodynamic roughness using satellite imagery. The formulas are expressed in terms of the subpixel fractional vegetation cover and one non-dimensional geometric parameter that characterizes the plant's shape. Geometrically similar plants and Poisson distributed plant centers are assumed. An appropriate averaging technique to extend satellite pixel-scale estimates to larger scales is provided. The parameterization is applied to the estimation of aerodynamic roughness using satellite imagery for a 2.3 sq km coniferous portion of the Landes Forest near Lubbon, France, during the 1986 HAPEX-Mobilhy Experiment. The canopy area index is estimated first for each pixel in the scene based on previous estimates of fractional cover obtained using Landsat Thematic Mapper imagery. Next, the results are incorporated into Raupach's (1992, 1994) analytical formulas for momentum roughness and zero-plane displacement height. The estimates compare reasonably well to reference values determined from measurements taken during the experiment and to published literature values. The approach offers the potential for estimating regionally variable, vegetation aerodynamic roughness lengths over natural regions using satellite imagery when there exists only limited knowledge of the vegetated surface.
17. On Parameterizing Turbulence in the Stably Stratified Atmospheric Boundary Layer
Wilson, Jordan M.; Venayagamoorthy, Subhas K.
2014-11-01
Parameterizing turbulent mixing in the stably stratified atmospheric boundary layer remains an active area of research connecting available field measurements with appropriate model parameters. The research presented studies the pertinent mixing lengths for shear- and buoyancy-dominated (or weakly stable and very stable) regimes in the stable atmospheric boundary layer (SABL). Incorporating shear and buoyancy effects, two length scales can be constructed, LkS =k 1 / 2 / S and LkN =k 1 / 2 / N , respectively. Extending the conceptual framework of Mater & Venayagamoorthy (2014), LkS and LkN are shown to be accurate representations of large-scale motions from which relevant model parameters are developed using observations from three field campaigns. An a priori analysis of large-eddy simulation (LES) data evaluates the efficacy of parameterizations applied to the vertical structure of the SABL. The results of this study provide a thorough evaluation of the pertinent mixing lengths in stably stratified turbulence through applications to atmospheric observations and numerical models for the boundary layer extendable to larger-scale weather prediction or global circulation models. S.K.V. gratefully acknowledges the support of the National Science Foundation under Grant No. OCE-1151838.
18. Transient Storage Parameterization of Wetland-dominated Stream Reaches
Wilderotter, S. M.; Lightbody, A.; Kalnejais, L. H.; Wollheim, W. M.
2014-12-01
Current understanding of the importance of transient storage in fluvial wetlands is limited. Wetlands that have higher connectivity to the main stream channel are important because they have the potential to retain more nitrogen within the river system than wetlands that receive little direct stream discharge. In this study, we investigated how stream water accesses adjacent fluvial wetlands in New England coastal watersheds to improve parameterization in network-scale models. Break through curves of Rhodamine WT were collected for eight wetlands in the Ipswich and Parker (MA) and Lamprey River (NH) watersheds, USA. The curves were inverse modeled using STAMMT-L to optimize the connectivity and size parameters for each reach. Two approaches were tested, a single dominant storage zone and a range of storage zones represented using a power-law distribution of storage zone connectivity. Multiple linear regression analyses were conducted to relate transient storage parameters to stream discharge, area, length-to-width ratio, and reach slope. Resulting regressions will enable more accurate parameterization of surface water transient storage in network-scale models.
19. The Reduced RUM as a Logit Model: Parameterization and Constraints.
PubMed
Chiu, Chia-Yi; Köhn, Hans-Friedrich
2016-06-01
Cognitive diagnosis models (CDMs) for educational assessment are constrained latent class models. Examinees are assigned to classes of intellectual proficiency defined in terms of cognitive skills called attributes, which an examinee may or may not have mastered. The Reduced Reparameterized Unified Model (Reduced RUM) has received considerable attention among psychometricians. Markov Chain Monte Carlo (MCMC) or Expectation Maximization (EM) are typically used for estimating the Reduced RUM. Commercial implementations of the EM algorithm are available in the latent class analysis (LCA) routines of Latent GOLD and Mplus, for example. Fitting the Reduced RUM with an LCA routine requires that it be reparameterized as a logit model, with constraints imposed on the parameters. For models involving two attributes, these have been worked out. However, for models involving more than two attributes, the parameterization and the constraints are nontrivial and currently unknown. In this article, the general parameterization of the Reduced RUM as a logit model involving any number of attributes and the associated parameter constraints are derived. As a practical illustration, the LCA routine in Mplus is used for fitting the Reduced RUM to two synthetic data sets and to a real-world data set; for comparison, the results obtained by using the MCMC implementation in OpenBUGS are also provided.
20. High-precision positioning of radar scatterers
Dheenathayalan, Prabu; Small, David; Schubert, Adrian; Hanssen, Ramon F.
2016-05-01
Remote sensing radar satellites cover wide areas and provide spatially dense measurements, with millions of scatterers. Knowledge of the precise position of each radar scatterer is essential to identify the corresponding object and interpret the estimated deformation. The absolute position accuracy of synthetic aperture radar (SAR) scatterers in a 2D radar coordinate system, after compensating for atmosphere and tidal effects, is in the order of centimeters for TerraSAR-X (TSX) spotlight images. However, the absolute positioning in 3D and its quality description are not well known. Here, we exploit time-series interferometric SAR to enhance the positioning capability in three dimensions. The 3D positioning precision is parameterized by a variance-covariance matrix and visualized as an error ellipsoid centered at the estimated position. The intersection of the error ellipsoid with objects in the field is exploited to link radar scatterers to real-world objects. We demonstrate the estimation of scatterer position and its quality using 20 months of TSX stripmap acquisitions over Delft, the Netherlands. Using trihedral corner reflectors (CR) for validation, the accuracy of absolute positioning in 2D is about 7 cm. In 3D, an absolute accuracy of up to ˜ 66 cm is realized, with a cigar-shaped error ellipsoid having centimeter precision in azimuth and range dimensions, and elongated in cross-range dimension with a precision in the order of meters (the ratio of the ellipsoid axis lengths is 1/3/213, respectively). The CR absolute 3D position, along with the associated error ellipsoid, is found to be accurate and agree with the ground truth position at a 99 % confidence level. For other non-CR coherent scatterers, the error ellipsoid concept is validated using 3D building models. In both cases, the error ellipsoid not only serves as a quality descriptor, but can also help to associate radar scatterers to real-world objects.
1. A Coordinated Effort to Improve Parameterization of High-Latitude Cloud and Radiation Processes
SciTech Connect
J. O. Pinto, A.H. Lynch
2005-12-14
The goal of this project is the development and evaluation of improved parameterization of arctic cloud and radiation processes and implementation of the parameterizations into a climate model. Our research focuses specifically on the following issues: (1) continued development and evaluation of cloud microphysical parameterizations, focusing on issues of particular relevance for mixed phase clouds; and (2) evaluation of the mesoscale simulation of arctic cloud system life cycles.
2. Total Cross Section Parameterizations for Pion Production in Nucleon-Nucleon Collisions
NASA Technical Reports Server (NTRS)
Norbury, John W.
2008-01-01
Total cross section parameterizations for neutral and charged pion production in nucleon-nuelcon collisions are compared to an extensive set of experimental data over the projectile momentum range from threshold to 300 GeV. Both proton-proton and proton-neutron reactions are considered. Good agreement between parameterizations and experiment is found, and therefore the parameterizations will be useful for applications, such as transport codes.
3. Survey of background scattering from materials found in small-angle neutron scattering
PubMed Central
Barker, J. G.; Mildner, D. F. R.
2015-01-01
Measurements and calculations of beam attenuation and background scattering for common materials placed in a neutron beam are presented over the temperature range of 300–700 K. Time-of-flight (TOF) measurements have also been made, to determine the fraction of the background that is either inelastic or quasi-elastic scattering as measured with a 3He detector. Other background sources considered include double Bragg diffraction from windows or samples, scattering from gases, and phonon scattering from solids. Background from the residual air in detector vacuum vessels and scattering from the 3He detector dome are presented. The thickness dependence of the multiple scattering correction for forward scattering from water is calculated. Inelastic phonon background scattering at small angles for crystalline solids is both modeled and compared with measurements. Methods of maximizing the signal-to-noise ratio by material selection, choice of sample thickness and wavelength, removal of inelastic background by TOF or Be filters, and removal of spin-flip scattering with polarized beam analysis are discussed. PMID:26306088
4. Scatter corrections for cone beam optical CT
Olding, Tim; Holmes, Oliver; Schreiner, L. John
2009-05-01
Cone beam optical computed tomography (OptCT) employing the VISTA scanner (Modus Medical, London, ON) has been shown to have significant promise for fast, three dimensional imaging of polymer gel dosimeters. One distinct challenge with this approach arises from the combination of the cone beam geometry, a diffuse light source, and the scattering polymer gel media, which all contribute scatter signal that perturbs the accuracy of the scanner. Beam stop array (BSA), beam pass array (BPA) and anti-scatter polarizer correction methodologies have been employed to remove scatter signal from OptCT data. These approaches are investigated through the use of well-characterized phantom scattering solutions and irradiated polymer gel dosimeters. BSA corrected scatter solutions show good agreement in attenuation coefficient with the optically absorbing dye solutions, with considerable reduction of scatter-induced cupping artifact at high scattering concentrations. The application of BSA scatter corrections to a polymer gel dosimeter lead to an overall improvement in the number of pixel satisfying the (3%, 3mm) gamma value criteria from 7.8% to 0.15%.
5. SU-E-T-597: Parameterization of the Photon Beam Dosimetry for a Commercial Linear Accelerator
SciTech Connect
Lebron, S; Lu, B; Yan, G; Kahler, D; Li, J; Barraclough, B; Liu, C
2015-06-15
Purpose: In radiation therapy, accurate data acquisition of photon beam dosimetric quantities is important for (1) beam modeling data input into a treatment planning system (TPS), (2) comparing measured and TPS modelled data, (3) a linear accelerator’s (linac) beam characteristics quality assurance process, and (4) establishing a standard data set for data comparison, etcetera. Parameterization of the photon beam dosimetry creates a portable data set that is easy to implement for different applications such as those previously mentioned. The aim of this study is to develop methods to parameterize photon percentage depth doses(PDD), profiles, and total scatter output factors(Scp). Methods: Scp, PDDs and profiles for different field sizes (from 2×2 to 40×40cm{sup 2}), depths and energies were measured in a linac using a three-dimensional water tank. All data were smoothed and profile data were also centered, symmetrized and geometrically scaled. The Scp and PDD data were analyzed using exponential functions. For modelling of open and wedge field profiles, each side was divided into three regions described by exponential, sigmoid and Gaussian equations. The model’s equations were chosen based on the physical principles described by these dosimetric quantities. The equations’ parameters were determined using a least square optimization method with the minimal amount of measured data necessary. The model’s accuracy was then evaluated via the calculation of absolute differences and distance–to–agreement analysis in low gradient and high gradient regions, respectively. Results: All differences in the PDDs’ buildup and the profiles’ penumbra regions were less than 2 mm and 0.5 mm, respectively. Differences in the low gradient regions were 0.20 ± 0.20% and 0.50 ± 0.35% for PDDs and profiles, respectively. For Scp data, all differences were less than 0.5%. Conclusion: This novel analytical model with minimum measurement requirements proved to accurately
6. FSP (Full Space Parameterization), Version 2.0
SciTech Connect
Fries, G.A.; Hacker, C.J.; Pin, F.G.
1995-10-01
This paper describes the modifications made to FSPv1.0 for the Full Space Parameterization (FSP) method, a new analytical method used to resolve underspecified systems of algebraic equations. The optimized code recursively searches for the necessary number of linearly independent vectors that are necessary to form the solution space. While doing this, it ensures that all possible combinations of solutions are checked, if needed, and handles complications which arise due to particular cases. In addition, two particular cases which cause failure of the FSP algorithm were discovered during testing of this new code. These cases are described in the context of how they are recognized and how they are handled by the new code. Finally, testing was performed on the new code using both isolated movements and complex trajectories for various mobile manipulators.
7. Parameterization of Aerosol Sinks in Chemical Transport Models
NASA Technical Reports Server (NTRS)
Colarco, Peter
2012-01-01
The modelers point of view is that the aerosol problem is one of sources, evolution, and sinks. Relative to evolution and sink processes, enormous attention is given to the problem of aerosols sources, whether inventory based (e.g., fossil fuel emissions) or dynamic (e.g., dust, sea salt, biomass burning). On the other hand, aerosol losses in models are a major factor in controlling the aerosol distribution and lifetime. Here we shine some light on how aerosol sinks are treated in modern chemical transport models. We discuss the mechanisms of dry and wet loss processes and the parameterizations for those processes in a single model (GEOS-5). We survey the literature of other modeling studies. We additionally compare the budgets of aerosol losses in several of the ICAP models.
8. A simple parameterization of aerosol emissions in RAMS
Letcher, Theodore
Throughout the past decade, a high degree of attention has been focused on determining the microphysical impact of anthropogenically enhanced concentrations of Cloud Condensation Nuclei (CCN) on orographic snowfall in the mountains of the western United States. This area has garnered a lot of attention due to the implications this effect may have on local water resource distribution within the Region. Recent advances in computing power and the development of highly advanced microphysical schemes within numerical models have provided an estimation of the sensitivity that orographic snowfall has to changes in atmospheric CCN concentrations. However, what is still lacking is a coupling between these advanced microphysical schemes and a real-world representation of CCN sources. Previously, an attempt to representation the heterogeneous evolution of aerosol was made by coupling three-dimensional aerosol output from the WRF Chemistry model to the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) (Ward et al. 2011). The biggest problem associated with this scheme was the computational expense. In fact, the computational expense associated with this scheme was so high, that it was prohibitive for simulations with fine enough resolution to accurately represent microphysical processes. To improve upon this method, a new parameterization for aerosol emission was developed in such a way that it was fully contained within RAMS. Several assumptions went into generating a computationally efficient aerosol emissions parameterization in RAMS. The most notable assumption was the decision to neglect the chemical processes in formed in the formation of Secondary Aerosol (SA), and instead treat SA as primary aerosol via short-term WRF-CHEM simulations. While, SA makes up a substantial portion of the total aerosol burden (much of which is made up of organic material), the representation of this process is highly complex and highly expensive within a numerical
9. Numerical-parameterized relativistic optimized effective potential for atoms
Buendía, E.; Gálvez, F. J.; Maldonado, P.; Sarsa, A.
2007-08-01
A numerical-parameterized solution of the relativistic optimized effective potential equations for atoms is proposed. The analytic continuation method is used to solve the single-particle Dirac equation. This method provides an accurate solution and allows for a straightforward use of the logarithmic transformation. The equations are solved within both a single and a multi-configurational framework. The single-configuration results for the ground state of the noble gases from Ne to Rn are compared with those obtained from a fully numerical solution of the relativistic optimized effective potential equations as well as with the Dirac-Hartree-Fock results. The performance of the multi-configuration version of the method is illustrated by studying a number of excited states of the carbon and iron atoms.
10. Parameterized Facial Expression Synthesis Based on MPEG-4
Raouzaiou, Amaryllis; Tsapatsoulis, Nicolas; Karpouzis, Kostas; Kollias, Stefanos
2002-12-01
In the framework of MPEG-4, one can include applications where virtual agents, utilizing both textual and multisensory data, including facial expressions and nonverbal speech help systems become accustomed to the actual feelings of the user. Applications of this technology are expected in educational environments, virtual collaborative workplaces, communities, and interactive entertainment. Facial animation has gained much interest within the MPEG-4 framework; with implementation details being an open research area (Tekalp, 1999). In this paper, we describe a method for enriching human computer interaction, focusing on analysis and synthesis of primary and intermediate facial expressions (Ekman and Friesen (1978)). To achieve this goal, we utilize facial animation parameters (FAPs) to model primary expressions and describe a rule-based technique for handling intermediate ones. A relation between FAPs and the activation parameter proposed in classical psychological studies is established, leading to parameterized facial expression analysis and synthesis notions, compatible with the MPEG-4 standard.
11. Criteria and algorithms for spectrum parameterization of MST radar signals
NASA Technical Reports Server (NTRS)
Rastogi, P. K.
1984-01-01
The power spectra S(f) of MST radar signals contain useful information about the variance of refractivity fluctuations, the mean radial velocity, and the radial velocity variance in the atmosphere. When noise and other contaminating signals are absent, these quantities can be obtained directly from the zeroth, first and second order moments of the spectra. A step-by-step procedure is outlined that can be used effectively to reduce large amounts of MST radar data-averaged periodograms measured in range and time to a parameterized form. The parameters to which a periodogram can be reduced are outlined and the steps in the procedure, that may be followed selectively, to arrive at the final set of reduced parameters are given. Examples of the performance of the procedure are given and its use with other radars are commented on.
12. Use of Cloud Computing to Calibrate a Highly Parameterized Model
Hayley, K. H.; Schumacher, J.; MacMillan, G.; Boutin, L.
2012-12-01
We present a case study using cloud computing to facilitate the calibration of a complex and highly parameterized model of regional groundwater flow. The calibration dataset consisted of many (~1500) measurements or estimates of static hydraulic head, a high resolution time series of groundwater extraction and disposal rates at 42 locations and pressure monitoring at 147 locations with a total of more than one million raw measurements collected over a ten year pumping history, and base flow estimates at 5 surface water monitoring locations. This modeling project was undertaken to assess the sustainability of groundwater withdrawal and disposal plans for insitu heavy oil extraction in Northeast Alberta, Canada. The geological interpretations used for model construction were based on more than 5,000 wireline logs collected throughout the 30,865 km2 regional study area (RSA), and resulted in a model with 28 slices, and 28 hydro stratigraphic units (average model thickness of 700 m, with aquifers ranging from a depth of 50 to 500 m below ground surface). The finite element FEFLOW model constructed on this geological interpretation had 331,408 nodes and required 265 time steps to simulate the ten year transient calibration period. This numerical model of groundwater flow required 3 hours to run on a on a server with two, 2.8 GHz processers and 16 Gb. RAM. Calibration was completed using PEST. Horizontal and vertical hydraulic conductivity as well as specific storage for each unit were independent parameters. For the recharge and the horizontal hydraulic conductivity in the three aquifers with the most transient groundwater use, a pilot point parameterization was adopted. A 7*7 grid of pilot points was defined over the RSA that defined a spatially variable horizontal hydraulic conductivity or recharge field. A 7*7 grid of multiplier pilot points that perturbed the more regional field was then superimposed over the 3,600 km2 local study area (LSA). The pilot point
13. Daily evaporation from drying soil: Universal parameterization with similarity
Brutsaert, Wilfried
2014-04-01
With supporting experimental evidence from three separate field studies of daily mean evaporation from bare soil with vastly different physical characteristics, it is shown that the process can be described as isothermal linear diffusion in a finite depth domain. The resulting solution leads directly to similarity variables and thus a universal parameterization, which should in principle be applicable to most field soils. In addition, a closed form expression is presented to estimate the weighted mean diffusivity for exponential type soil water diffusivities. In this solution, the widely used square root of inverse time proportionality of this phenomenon is its short time version, whereas the exponential decay proportionality, proposed however by several authors for vegetated surfaces, is its long time version. It appears that in many situations the soil layer contributing to evaporation is fairly shallow and only a few tens of centimeters thick.
14. Parameterization of ion channeling half-angles and minimum yields
Doyle, Barney L.
2016-03-01
A MS Excel program has been written that calculates ion channeling half-angles and minimum yields in cubic bcc, fcc and diamond lattice crystals. All of the tables and graphs in the three Ion Beam Analysis Handbooks that previously had to be manually looked up and read from were programed into Excel in handy lookup tables, or parameterized, for the case of the graphs, using rather simple exponential functions with different power functions of the arguments. The program then offers an extremely convenient way to calculate axial and planar half-angles, minimum yields, effects on half-angles and minimum yields of amorphous overlayers. The program can calculate these half-angles and minimum yields for axes and [h k l] planes up to (5 5 5). The program is open source and available at
15. Parameterized modeling and estimation of spatially varying optical blur
Simpkins, Jonathan D.; Stevenson, Robert L.
2015-02-01
Optical blur can display significant spatial variation across the image plane, even for constant camera settings and object depth. Existing solutions to represent this spatially varying blur requires a dense sampling of blur kernels across the image, where each kernel is defined independent of the neighboring kernels. This approach requires a large amount of data collection, and the estimation of the kernels is not as robust as if it were possible to incorporate knowledge of the relationship between adjacent kernels. A novel parameterized model is presented which relates the blur kernels at different locations across the image plane. The model is motivated by well-established optical models, including the Seidel aberration model. It is demonstrated that the proposed model can unify a set of hundreds of blur kernel observations across the image plane under a single 10-parameter model, and the accuracy of the model is demonstrated with simulations and measurement data collected by two separate research groups.
16. A stratiform cloud parameterization for General Circulation Models
SciTech Connect
Ghan, S.J.; Leung, L.R.; Chuang, C.C.; Penner, J.E.; McCaa, J.
1994-05-01
The crude treatment of clouds in General Circulation Models (GCMs) is widely recognized as a major limitation in the application of these models to predictions of global climate change. The purpose of this project is to develop a paxameterization for stratiform clouds in GCMs that expresses stratiform clouds in terms of bulk microphysical properties and their subgrid variability. In this parameterization, precipitating cloud species are distinguished from non-precipitating species, and the liquid phase is distinguished from the ice phase. The size of the non-precipitating cloud particles (which influences both the cloud radiative properties and the conversion of non-precipitating cloud species to precipitating species) is determined by predicting both the mass and number concentrations of each species.
17. Effects of Pre-Existing Ice Crystals on Cirrus Clouds and Comparison between Different Ice Nucleation Parameterizations with the Community Atmosphere Model (CAM5)
SciTech Connect
Shi, Xiangjun; Liu, Xiaohong; Zhang, Kai
2015-01-01
In order to improve the treatment of ice nucleation in a more realistic manner in the Community Atmospheric Model version 5.3 (CAM5.3), the effects of preexisting ice crystals on ice nucleation in cirrus clouds are considered. In addition, by considering the in-cloud variability in ice saturation ratio, homogeneous nucleation takes place spatially only in a portion of cirrus cloud rather than in the whole area of cirrus cloud. With these improvements, the two unphysical limiters used in the representation of ice nucleation are removed. Compared to observations, the ice number concentrations and the probability distributions of ice number concentration are both improved with the updated treatment. The preexisting ice crystals significantly reduce ice number concentrations in cirrus clouds, especially at mid- to high latitudes in the upper troposphere (by a factor of ~10). Furthermore, the contribution of heterogeneous ice nucleation to cirrus ice crystal number increases considerably.Besides the default ice nucleation parameterization of Liu and Penner (2005, hereafter LP) in CAM5.3, two other ice nucleation parameterizations of Barahona and Nenes (2009, hereafter BN) and Kärcher et al. (2006, hereafter KL) are implemented in CAM5.3 for the comparison. In-cloud ice crystal number concentration, percentage contribution from heterogeneous ice nucleation to total ice crystal number, and preexisting ice effects simulated by the three ice nucleation parameterizations have similar patterns in the simulations with present-day aerosol emissions. However, the change (present-day minus pre-industrial times) in global annual mean column ice number concentration from the KL parameterization (3.24×106 m-2) is obviously less than that from the LP (8.46×106 m-2) and BN (5.62×106 m-2) parameterizations. As a result, experiment using the KL parameterization predicts a much smaller anthropogenic aerosol longwave indirect forcing (0.24 W m-2) than that using the LP (0.46 W m-2
18. Parameterization of Infrared Absorption in Midlatitude Cirrus Clouds
SciTech Connect
Sassen, Kenneth; Wang, Zhien; Platt, C.M.R.; Comstock, Jennifer M.
2003-01-01
Employing a new approach based on combined Raman lidar and millimeter-wave radar measurements and a parameterization of the infrared absorption coefficient {sigma}{sub a}(km{sup -1}) in terms of retrieved cloud microphysics, we derive a statistical relation between {sigma}{sub a} and cirrus cloud temperature. The relations {sigma}{sub a} = 0.3949 + 5.3886 x 10{sup -3} T + 1.526 x 10{sup -5} T{sup 2} for ambient temperature (T,{sup o}C), and {sigma}{sub a} = 0.2896 + 3.409 x 10{sup -3} T{sub m} for midcloud temperature (T{sub m}, {sup o}C), are found using a second order polynomial fit. Comparison with two {sigma}{sub a} versus T{sub m} relations obtained primarily from midlatitude cirrus using the combined lidar/infrared radiometer (LIRAD) approach reveals significant differences. However, we show that this reflects both the previous convention used in curve fitting (i. e., {sigma}{sub a} {yields} 0 at {approx} 80 C), and the types of clouds included in the datasets. Without such constraints, convergence is found in the three independent remote sensing datasets within the range of conditions considered valid for cirrus (i.e., cloud optical depth {approx} 3.0 and T{sub m} < {approx}20 C). Hence for completeness we also provide reanalyzed parameterizations for a visible extinction coefficient {sigma}{sub a} versus T{sub m} relation for midlatitude cirrus, and a data sample involving cirrus that evolved into midlevel altostratus clouds with higher optical depths.
19. Modeling Jupiter's Quasi Quadrennial Oscillation (QQO) with Wave Drag Parameterizations
Cosentino, Rick; Morales-Juberias, Raul; Greathouse, Thomas K.; Orton, Glenn S.
2016-10-01
The QQO in Jupiter's atmosphere was first discovered after 7.8 micron infrared observations spanning the 1980's and 1990's detected a temperature oscillation near 10 hPa (Orton et al. 1991, Science 252, 537, Leovy et. al. 1991, Nature 354, 380, Friedson 1999, Icarus 137, 34). New observations using the Texas Echelon cross-dispersed Echelle Spectrograph (TEXES), mounted on the NASA Infrared Telescope facility (IRTF), have been used to characterize a complete cycle of the QQO between January 2012 and January 2016 (Greathouse et al. 2016, DPS) . These new observations not only show the thermal oscillation at 10 hPa, but they also show that the QQO extends upwards in Jupiter's atmosphere to pressures as high as 0.4 hPa. We incorporated three different wave-drag parameterizations into the EPIC General Circulation Model (Dowling et al. 1998, Icarus 132, 221) to simulate the observed Jovian QQO temperature signatures as a function of latitude, pressure and time using results from the TEXES datasets as new constraints. Each parameterization produces unique results and offers insight into the spectra of waves that likely exist in Jupiter's atmosphere to force the QQO. High-frequency gravity waves produced from convection are extremely difficult to directly observe but likely contribute a significant portion to the QQO momentum budget. We use different models to simulate the effects of waves such as these, to indirectly explore their spectrum in Jupiter's atmosphere by varying their properties. The model temperature outputs show strong correlations to equatorial and mid-latitude temperature fields retrieved from the TEXES datasets at different epochs. Our results suggest the QQO phenomenon could be more than one alternating zonal jet that descends over time in response to Jovian atmospheric forcing (e.g. gravity waves from convection).Research funding provided by the NRAO Grote Reber Pre-Doctoral Fellowship. Computing resources include the NMT PELICAN cluster and the CISL
20. Mesoscale Eddy Parameterization in an Idealized Primitive Equations Model
Anstey, J.; Zanna, L.
2014-12-01
Large-scale ocean currents such as the Gulf Stream and Kuroshio Extension are strongly influenced by mesoscale eddies, which have spatial scales of order 10-100 km. The effects of these eddies are poorly represented in many state-of-the-art ocean general circulation models (GCMs) due to the inadequate spatial resolution of these models. In this study we examine the response of the large-scale ocean circulation to the rectified effects of eddy forcing - i.e., the role played by surface-intensified mesoscale eddies in sustaining and modulating an eastward jet that separates from an intense western boundary current (WBC). For this purpose a primitive equations ocean model (the MITgcm) in an idealized wind-forced double-gyre configuration is integrated at eddy-resolving resolution to reach a forced-dissipative equilibrium state that captures the essential dynamics of WBC-extension jets. The rectified eddy forcing is diagnosed as a stochastic function of the large-scale state, this being characterized by the manner in which potential vorticity (PV) contours become deformed. Specifically, a stochastic function based on the Laplacian of the material rate of change of PV is examined in order to compare the primitive equations results with those of a quasi-geostrophic model in which this function has shown some utility as a parameterization of eddy effects (Porta Mana and Zanna, 2014). The key question is whether an eddy parameterization based on quasi-geostrophic scaling is able to carry over to a system in which this scaling is not imposed (i.e. the primitive equations), in which unbalanced motions occur.
1. Ameriflux data used for verification of surface layer parameterizations
Tassone, Caterina; Ek, Mike
2015-04-01
The atmospheric surface-layer parameterization is an important component in a coupled model, as its output, the surface exchange coefficients for momentum, heat and humidity, are used to determine the fluxes of these quantities between the land-surface and the atmosphere. An accurate prediction of these fluxes is therefore required in order to provide a correct forecast of the surface temperature, humidity and ultimately also the precipitation in a model. At the NOAA/NCEP Environmental Modeling Center, a one-dimensional Surface Layer Simulator (SLS) has been developed for simulating the surface layer and its interface. Two different configurations of the SLS exist, replicating in essence the way in which the surface layer is simulated in the GFS and the NAM, respectively. Input data for the SLS are the basic atmospheric quantities of winds, temperature, humidity and pressure evaluated at a specific height above the ground, surface values of temperature and humidity, and the momentum roughness length z0. The output values of the SLS are the surface exchange coefficients for heat and momentum. The exchange coefficients computed by the SLS are then compared with independent estimates derived from measured surface heat fluxes. The SLS is driven by a set of Ameriflux data acquired at 22 stations over a period of several years. This provides a large number of different vegetation characteristics and helps ensure statistical significance. Even though there are differences in the respective surface layer formulations between the GFS and the NAM, they are both based on similarity theory, and therefore lower boundary conditions, i.e. roughness lengths for momentum and heat, and profile functions are among the main components of the surface layer that need to be evaluated. The SLS is a very powerful tool for this type of evaluation. We present the results of the Ameriflux comparison and discuss the implications of our results for the surface layer parameterizations of the NAM
2. Systematic Parameterization of Monovalent Ions Employing the Nonbonded Model.
PubMed
Li, Pengfei; Song, Lin Frank; Merz, Kenneth M
2015-04-14
Monovalent ions play fundamental roles in many biological processes in organisms. Modeling these ions in molecular simulations continues to be a challenging problem. The 12-6 Lennard-Jones (LJ) nonbonded model is widely used to model monovalent ions in classical molecular dynamics simulations. A lot of parameterization efforts have been reported for these ions with a number of experimental end points. However, some reported parameter sets do not have a good balance between the two Lennard-Jones parameters (the van der Waals (VDW) radius and potential well depth), which affects their transferability. In the present work, via the use of a noble gas curve we fitted in former work (J. Chem. Theory Comput. 2013, 9, 2733), we reoptimized the 12-6 LJ parameters for 15 monovalent ions (11 positive and 4 negative ions) for three extensively used water models (TIP3P, SPC/E, and TIP4P(EW)). Since the 12-6 LJ nonbonded model performs poorly in some instances for these ions, we have also parameterized the 12-6-4 LJ-type nonbonded model (J. Chem. Theory Comput. 2014, 10, 289) using the same three water models. The three derived parameter sets focused on reproducing the hydration free energies (the HFE set) and the ion-oxygen distance (the IOD set) using the 12-6 LJ nonbonded model and the 12-6-4 LJ-type nonbonded model (the 12-6-4 set) overall give improved results. In particular, the final parameter sets showed better agreement with quantum mechanically calculated VDW radii and improved transferability to ion-pair solutions when compared to previous parameter sets. PMID:26574374
3. A parameterization of the ice-ocean drag coefficient
Lu, Peng; Li, Zhijun; Cheng, Bin; LeppäRanta, Matti
2011-07-01
A parameterization of the ice-ocean drag coefficient (Cw) was developed through partitioning the oceanic drag force into three components: (1) form drag on the floe edge, (2) form drag on the ridge keel, and (3) skin friction on the ice bottom. Through these quantities, Cw was expressed as a function of observable sea ice geometric parameters. Sensitivity studies were carried out to investigate the influence of varying sea ice conditions on Cw. The results revealed that Cw increases first and then decreases with increasing ice concentration (A), similar to the observations of the air-ice drag coefficient, and which is mainly attributed to the nonmonotonic variation of the form drag on the floe edge with ice concentration. Moreover, the form drag on the floe edge is always the dominant component, having a proportion of more than 60% in sea ice with a large aspect ratio (draft/length ≥ 1/100), indicating the necessity of including this term in sea ice dynamic models, particularly for the marginal ice zone (MIZ). The form drag on the ridge keel becomes dominant only when the ridging intensity is extremely high (depth/spacing ≥ 1/20). Additionally, a large value of Cw cannot be caused only by the inclusion of form drag terms but also by large skin friction over rough ice bottoms. Finally, for typical situations in the MIZ with moderate ridging intensity, the parameterization will underestimate Cw by approximately 30% for a rough ice bottom and by over 80% for a smooth ice bottom if no form drags are considered.
4. Sensitivity of Antarctic sea ice to form drag parameterization
Barbic, Gaia; Tsamados, Michel; Petty, Alek; Schroeder, David; Holland, Paul; Feltham, Daniel
2014-05-01
A new drag parametrization accounting explicitly for form drag has been recently formulated and applied to the Arctic sea ice (Lupkes et al, 2012 and Tsamados et al, 2014). We summarize here the fundamental elements of this formulation and we then adapt it to the Antarctic sea ice. Considering the general expression of the momentum balance of sea ice, we analyze the total (neutral) drag coefficients by studying separately air-ice and ocean-ice momentum fluxes, and by introducing the parameterization for both the atmospheric neutral drag coeffcient (ANDC) and the oceanic neutral drag coeffcient (ONDC). The two coefficients are calculated as a sum of their skin frictional contribution and form drag contribution, which comes from ridges and floe edges for the ANDC and keels and floe edges for the ONDC. Due to the contrasting geography of the two polar regions, there are important differences, both dynamic and thermodynamic, between Arctic and Antarctic sea ice. In the Antarctic, sea ice is younger, less ridged (hence thinner and smoother). Due to the intense snowfalls, the snow cover is generally thicker than in the Arctic, with values that vary significantly both seasonally and regionally and can affect the roughness of the surface and can lead to flooding of the ice. At the outer boundary of the Southern Ocean, the ice is unconstrained by land, divergent and subject to meridional advection, which leads to a much faster ice drift than in the Arctic. We show here how the new parameterization accounting for form drag influences the Antarctic sea ice characteristics.
5. Precisely parameterized experimental and computational models of tissue organization.
PubMed
Molitoris, Jared M; Paliwal, Saurabh; Sekar, Rajesh B; Blake, Robert; Park, JinSeok; Trayanova, Natalia A; Tung, Leslie; Levchenko, Andre
2016-02-01
Patterns of cellular organization in diverse tissues frequently display a complex geometry and topology tightly related to the tissue function. Progressive disorganization of tissue morphology can lead to pathologic remodeling, necessitating the development of experimental and theoretical methods of analysis of the tolerance of normal tissue function to structural alterations. A systematic way to investigate the relationship of diverse cell organization to tissue function is to engineer two-dimensional cell monolayers replicating key aspects of the in vivo tissue architecture. However, it is still not clear how this can be accomplished on a tissue level scale in a parameterized fashion, allowing for a mathematically precise definition of the model tissue organization and properties down to a cellular scale with a parameter dependent gradual change in model tissue organization. Here, we describe and use a method of designing precisely parameterized, geometrically complex patterns that are then used to control cell alignment and communication of model tissues. We demonstrate direct application of this method to guiding the growth of cardiac cell cultures and developing mathematical models of cell function that correspond to the underlying experimental patterns. Several anisotropic patterned cultures spanning a broad range of multicellular organization, mimicking the cardiac tissue organization of different regions of the heart, were found to be similar to each other and to isotropic cell monolayers in terms of local cell-cell interactions, reflected in similar confluency, morphology and connexin-43 expression. However, in agreement with the model predictions, different anisotropic patterns of cell organization, paralleling in vivo alterations of cardiac tissue morphology, resulted in variable and novel functional responses with important implications for the initiation and maintenance of cardiac arrhythmias. We conclude that variations of tissue geometry and topology
6. Synthesizing 3D Surfaces from Parameterized Strip Charts
NASA Technical Reports Server (NTRS)
Robinson, Peter I.; Gomez, Julian; Morehouse, Michael; Gawdiak, Yuri
2004-01-01
We believe 3D information visualization has the power to unlock new levels of productivity in the monitoring and control of complex processes. Our goal is to provide visual methods to allow for rapid human insight into systems consisting of thousands to millions of parameters. We explore this hypothesis in two complex domains: NASA program management and NASA International Space Station (ISS) spacecraft computer operations. We seek to extend a common form of visualization called the strip chart from 2D to 3D. A strip chart can display the time series progression of a parameter and allows for trends and events to be identified. Strip charts can be overlayed when multiple parameters need to visualized in order to correlate their events. When many parameters are involved, the direct overlaying of strip charts can become confusing and may not fully utilize the graphing area to convey the relationships between the parameters. We provide a solution to this problem by generating 3D surfaces from parameterized strip charts. The 3D surface utilizes significantly more screen area to illustrate the differences in the parameters and the overlayed strip charts, and it can rapidly be scanned by humans to gain insight. The selection of the third dimension must be a parallel or parameterized homogenous resource in the target domain, defined using a finite, ordered, enumerated type, and not a heterogeneous type. We demonstrate our concepts with examples from the NASA program management domain (assessing the state of many plans) and the computers of the ISS (assessing the state of many computers). We identify 2D strip charts in each domain and show how to construct the corresponding 3D surfaces. The user can navigate the surface, zooming in on regions of interest, setting a mark and drilling down to source documents from which the data points have been derived. We close by discussing design issues, related work, and implementation challenges.
7. Preprocessing and parameterizing bioimpedance spectroscopy measurements by singular value decomposition.
PubMed
2015-05-01
In several applications of bioimpedance spectroscopy, the measured spectrum is parameterized by being fitted into the Cole equation. However, the extracted Cole parameters seem to be inconsistent from one measurement session to another, which leads to a high standard deviation of extracted parameters. This inconsistency is modeled with a source of random variations added to the voltage measurement carried out in the time domain. These random variations may originate from biological variations that are irrelevant to the evidence that we are investigating. Yet, they affect the voltage measured by using a bioimpedance device based on which magnitude and phase of impedance are calculated.By means of simulated data, we showed that Cole parameters are highly affected by this type of variation. We further showed that singular value decomposition (SVD) is an effective tool for parameterizing bioimpedance measurements, which results in more consistent parameters than Cole parameters. We propose to apply SVD as a preprocessing method to reconstruct denoised bioimpedance measurements. In order to evaluate the method, we calculated the relative difference between parameters extracted from noisy and clean simulated bioimpedance spectra. Both mean and standard deviation of this relative difference are shown to effectively decrease when Cole parameters are extracted from preprocessed data in comparison to being extracted from raw measurements.We evaluated the performance of the proposed method in distinguishing three arm positions, for a set of experiments including eight subjects. It is shown that Cole parameters of different positions are not distinguishable when extracted from raw measurements. However, one arm position can be distinguished based on SVD scores. Moreover, all three positions are shown to be distinguished by two parameters, R0/R∞ and Fc, when Cole parameters are extracted from preprocessed measurements. These results suggest that SVD could be considered as an
8. Parameterization of tree-ring growth in Siberia
Tychkov, Ivan; Popkova, Margarita; Shishov, Vladimir; Vaganov, Eugene
2016-04-01
No doubt, climate-tree growth relationship is an one of the useful and interesting subject of studying in dendrochronology. It provides an information of tree growth dependency on climatic environment, but also, gives information about growth conditions and whole tree-ring growth process for long-term periods. New parameterization approach of the Vaganov-Shashkin process-based model (VS-model) is developed to described critical process linking climate variables with tree-ring formation. The approach (co-called VS-Oscilloscope) is presented as a computer software with graphical interface. As most process-based tree-ring models, VS-model's initial purpose is to describe variability of tree-ring radial growth due to variability of climatic factors, but also to determinate principal factors limiting tree-ring growth. The principal factors affecting on the growth rate of cambial cells in the VS-model are temperature, day light and soil moisture. Detailed testing of VS-Oscilloscope was done for semi-arid area of southern Siberia (Khakassian region). Significant correlations between initial tree-ring chronologies and simulated tree-ring growth curves were obtained. Direct natural observations confirm obtained simulation results including unique growth characteristic for semi-arid habitats. New results concerning formation of wide and narrow rings under different climate conditions are considered. By itself the new parameterization approach (VS-oscilloscope) is an useful instrument for better understanding of various processes in tree-ring formation. The work was supported by the Russian Science Foundation (RSF # 14-14-00219).
9. Research on aerosol profiles and parameterization scheme in Southeast China
Wang, Gang; Deng, Tao; Tan, Haobo; Liu, Xiantong; Yang, Honglong
2016-09-01
The vertical distribution of the aerosol extinction coefficient serves as a basis for evaluating aerosol radiative forcing and air quality modeling. In this study, MODIS AOD data and ground-based lidar extinction coefficients were employed to verify 6 years (2009-2014) aerosol extinction data obtained via CALIOP for Southeast China. The objective was mainly to provide the parameterization scheme of annual and seasonal aerosol extinction profiles. The results showed that the horizontal and vertical distributions of CALIOP extinction data were highly accurate in Southeast China. The annual average AOD below 2 km accounted for 64% of the total layer, with larger proportions observed in winter (80%) and autumn (80%) and lower proportions observed in summer (70%) and spring (59%). The AOD was maximum in the spring (0.58), followed by the autumn and winter (0.44), and reached a minimum in the summer (0.40). The near-surface extinction coefficient increased from summer, spring, autumn and winter, in that order. The Elterman profile is obviously lower than the profiles observed by CALIOP in Southeast China. The annual average and seasonal aerosol profiles showed an exponential distribution, and could be divided into two sections. Two sections exponential fitting was used in the parameterization scheme. In the first section, the aerosol scale height reached 2200 m with a maximum (3,500 m) in summer and a minimum (1,230 m) in winter, which meant that the aerosol extinction decrease with height slower in summer, but more rapidly in winter. In second section, the aerosol scale height was maximum in spring, which meant that the higher aerosol diffused in spring.
10. Parameterization of wind turbine impacts on hydrodynamics and sediment transport
Rivier, Aurélie; Bennis, Anne-Claire; Pinon, Grégory; Magar, Vanesa; Gross, Markus
2016-10-01
Monopile foundations of offshore wind turbines modify the hydrodynamics and sediment transport at local and regional scales. The aim of this work is to assess these modifications and to parameterize them in a regional model. In the present study, this is achieved through a regional circulation model, coupled with a sediment transport module, using two approaches. One approach is to explicitly model the monopiles in the mesh as dry cells, and the other is to parameterize them by adding a drag force term to the momentum and turbulence equations. Idealised cases are run using hydrodynamical conditions and sediment grain sizes typical from the area located off Courseulles-sur-Mer (Normandy, France), where an offshore windfarm is under planning, to assess the capacity of the model to reproduce the effect of the monopile on the environment. Then, the model is applied to a real configuration on an area including the future offshore windfarm of Courseulles-sur-Mer. Four monopiles are represented in the model using both approaches, and modifications of the hydrodynamics and sediment transport are assessed over a tidal cycle. In relation to local hydrodynamic effects, it is observed that currents increase at the side of the monopile and decrease in front of and downstream of the monopile. In relation to sediment transport effect, the results show that resuspension and erosion occur around the monopile in locations where the current speed increases due to the monopile presence, and sediments deposit downstream where the bed shear stress is lower. During the tidal cycle, wakes downstream of the monopile reach the following monopile and modify the velocity magnitude and suspended sediment concentration patterns around the second monopile.
11. Parameterization of wind turbine impacts on hydrodynamics and sediment transport
Rivier, Aurélie; Bennis, Anne-Claire; Pinon, Grégory; Magar, Vanesa; Gross, Markus
2016-09-01
Monopile foundations of offshore wind turbines modify the hydrodynamics and sediment transport at local and regional scales. The aim of this work is to assess these modifications and to parameterize them in a regional model. In the present study, this is achieved through a regional circulation model, coupled with a sediment transport module, using two approaches. One approach is to explicitly model the monopiles in the mesh as dry cells, and the other is to parameterize them by adding a drag force term to the momentum and turbulence equations. Idealised cases are run using hydrodynamical conditions and sediment grain sizes typical from the area located off Courseulles-sur-Mer (Normandy, France), where an offshore windfarm is under planning, to assess the capacity of the model to reproduce the effect of the monopile on the environment. Then, the model is applied to a real configuration on an area including the future offshore windfarm of Courseulles-sur-Mer. Four monopiles are represented in the model using both approaches, and modifications of the hydrodynamics and sediment transport are assessed over a tidal cycle. In relation to local hydrodynamic effects, it is observed that currents increase at the side of the monopile and decrease in front of and downstream of the monopile. In relation to sediment transport effect, the results show that resuspension and erosion occur around the monopile in locations where the current speed increases due to the monopile presence, and sediments deposit downstream where the bed shear stress is lower. During the tidal cycle, wakes downstream of the monopile reach the following monopile and modify the velocity magnitude and suspended sediment concentration patterns around the second monopile.
12. Precisely parameterized experimental and computational models of tissue organization†
PubMed Central
Sekar, Rajesh B.; Blake, Robert; Park, JinSeok; Trayanova, Natalia A.; Tung, Leslie; Levchenko, Andre
2016-01-01
Patterns of cellular organization in diverse tissues frequently display a complex geometry and topology tightly related to the tissue function. Progressive disorganization of tissue morphology can lead to pathologic remodeling, necessitating the development of experimental and theoretical methods of analysis of the tolerance of normal tissue function to structural alterations. A systematic way to investigate the relationship of diverse cell organization to tissue function is to engineer two-dimensional cell monolayers replicating key aspects of the in vivo tissue architecture. However, it is still not clear how this can be accomplished on a tissue level scale in a parameterized fashion, allowing for a mathematically precise definition of the model tissue organization and properties down to a cellular scale with a parameter dependent gradual change in model tissue organization. Here, we describe and use a method of designing precisely parameterized, geometrically complex patterns that are then used to control cell alignment and communication of model tissues. We demonstrate direct application of this method to guiding the growth of cardiac cell cultures and developing mathematical models of cell function that correspond to the underlying experimental patterns. Several anisotropic patterned cultures spanning a broad range of multicellular organization, mimicking the cardiac tissue organization of different regions of the heart, were found to be similar to each other and to isotropic cell monolayers in terms of local cell–cell interactions, reflected in similar confluency, morphology and connexin-43 expression. However, in agreement with the model predictions, different anisotropic patterns of cell organization, paralleling in vivo alterations of cardiac tissue morphology, resulted in variable and novel functional responses with important implications for the initiation and maintenance of cardiac arrhythmias. We conclude that variations of tissue geometry and
13. Preferences for tap water attributes within couples: An exploration of alternative mixed logit parameterizations
Scarpa, Riccardo; Thiene, Mara; Hensher, David A.
2012-01-01
Preferences for attributes of complex goods may differ substantially among members of households. Some of these goods, such as tap water, are jointly supplied at the household level. This issue of jointness poses a series of theoretical and empirical challenges to economists engaged in empirical nonmarket valuation studies. While a series of results have already been obtained in the literature, the issue of how to empirically measure these differences, and how sensitive the results are to choice of model specification from the same data, is yet to be clearly understood. In this paper we use data from a widely employed form of stated preference survey for multiattribute goods, namely choice experiments. The salient feature of the data collection is that the same choice experiment was applied to both partners of established couples. The analysis focuses on models that simultaneously handle scale as well as preference heterogeneity in marginal rates of substitution (MRS), thereby isolating true differences between members of couples in their MRS, by removing interpersonal variation in scale. The models employed are different parameterizations of the mixed logit model, including the willingness to pay (WTP)-space model and the generalized multinomial logit model. We find that in this sample there is some evidence of significant statistical differences in values between women and men, but these are of small magnitude and only apply to a few attributes.
14. Parameterization of clear-sky surface irradiance and its implications for estimation of aerosol direct radiative effect and aerosol optical depth
PubMed Central
Xia, Xiangao
2015-01-01
Aerosols impact clear-sky surface irradiance () through the effects of scattering and absorption. Linear or nonlinear relationships between aerosol optical depth (τa) and have been established to describe the aerosol direct radiative effect on (ADRE). However, considerable uncertainties remain associated with ADRE due to the incorrect estimation of (τa in the absence of aerosols). Based on data from the Aerosol Robotic Network, the effects of τa, water vapor content (w) and the cosine of the solar zenith angle (μ) on are thoroughly considered, leading to an effective parameterization of as a nonlinear function of these three quantities. The parameterization is proven able to estimate with a mean bias error of 0.32 W m−2, which is one order of magnitude smaller than that derived using earlier linear or nonlinear functions. Applications of this new parameterization to estimate τa from , or vice versa, show that the root-mean-square errors were 0.08 and 10.0 Wm−2, respectively. Therefore, this study establishes a straightforward method to derive from τa or estimate τa from measurements if water vapor measurements are available. PMID:26395310
15. Reactive uptake coefficients for N2O5 determined from aircraft measurements during the Second Texas Air Quality Study: Comparison to current model parameterizations
Brown, Steven S.; Dubé, William P.; Fuchs, Hendrik; Ryerson, Thomas B.; Wollny, Adam G.; Brock, Charles A.; Bahreini, Roya; Middlebrook, Ann M.; Neuman, J. Andrew; Atlas, Elliot; Roberts, James M.; Osthoff, Hans D.; Trainer, Michael; Fehsenfeld, Frederick C.; Ravishankara, A. R.
2009-04-01
This paper presents determinations of reactive uptake coefficients for N2O5, γ(N2O5), on aerosols from nighttime aircraft measurements of ozone, nitrogen oxides, and aerosol surface area on the NOAA P-3 during Second Texas Air Quality Study (TexAQS II). Determinations based on both the steady state approximation for NO3 and N2O5 and a plume modeling approach yielded γ(N2O5) substantially smaller than current parameterizations used for atmospheric modeling and generally in the range 0.5-6 × 10-3. Dependence of γ(N2O5) on variables such as relative humidity and aerosol composition was not apparent in the determinations, although there was considerable scatter in the data. Determinations were also inconsistent with current parameterizations of the rate coefficient for homogenous hydrolysis of N2O5 by water vapor, which may be as much as a factor of 10 too large. Nocturnal halogen activation via conversion of N2O5 to ClNO2 on chloride aerosol was not determinable from these data, although limits based on laboratory parameterizations and maximum nonrefractory aerosol chloride content showed that this chemistry could have been comparable to direct production of HNO3 in some cases.
16. Parameterization of clear-sky surface irradiance and its implications for estimation of aerosol direct radiative effect and aerosol optical depth
Xia, Xiangao
2015-09-01
Aerosols impact clear-sky surface irradiance () through the effects of scattering and absorption. Linear or nonlinear relationships between aerosol optical depth (τa) and have been established to describe the aerosol direct radiative effect on (ADRE). However, considerable uncertainties remain associated with ADRE due to the incorrect estimation of (τa in the absence of aerosols). Based on data from the Aerosol Robotic Network, the effects of τa, water vapor content (w) and the cosine of the solar zenith angle (μ) on are thoroughly considered, leading to an effective parameterization of as a nonlinear function of these three quantities. The parameterization is proven able to estimate with a mean bias error of 0.32 W m-2, which is one order of magnitude smaller than that derived using earlier linear or nonlinear functions. Applications of this new parameterization to estimate τa from , or vice versa, show that the root-mean-square errors were 0.08 and 10.0 Wm-2, respectively. Therefore, this study establishes a straightforward method to derive from τa or estimate τa from measurements if water vapor measurements are available.
17. Impact of Apex Model parameterization strategy on estimated benefit of conservation practices
Technology Transfer Automated Retrieval System (TEKTRAN)
Three parameterized Agriculture Policy Environmental eXtender (APEX) models for corn-soybean rotation on clay pan soils were developed with the objectives, 1. Evaluate model performance of three parameterization strategies on a validation watershed; and 2. Compare predictions of water quality benefi...
18. A shallow convection parameterization for the non-hydrostatic MM5 mesoscale model
SciTech Connect
Seaman, N.L.; Kain, J.S.; Deng, A.
1996-04-01
A shallow convection parameterization suitable for the Pennsylvannia State University (PSU)/National Center for Atmospheric Research nonhydrostatic mesoscale model (MM5) is being developed at PSU. The parameterization is based on parcel perturbation theory developed in conjunction with a 1-D Mellor Yamada 1.5-order planetary boundary layer scheme and the Kain-Fritsch deep convection model.
19. Improved parameterization for the vertical flux of dust aerosols emitted by an eroding soil
Technology Transfer Automated Retrieval System (TEKTRAN)
The representation of the dust cycle in atmospheric circulation models hinges on an accurate parameterization of the vertical dust flux at emission. However, existing parameterizations of the vertical dust flux vary substantially in their scaling with wind friction velocity, require input parameters...
20. Parameterization of spectral distributions for pion and kaon production in proton-proton collisions
NASA Technical Reports Server (NTRS)
Schneider, John P.; Norbury, John W.; Cucinotta, Frank A.
1995-01-01
Accurate semi-empirical parameterizations of the energy-differential cross sections for charged pion and kaon production from proton-proton collisions are presented at energies relevant to cosmic rays. The parameterizations depend on the outgoing meson momentum and also the proton energy, and are able to be reduced to very simple analytical formulas suitable for cosmic-ray transport.
1. The CCPP-ARM Parameterization Testbed (CAPT): Where Climate Simulation Meets Weather Prediction
SciTech Connect
Phillips, T J; Potter, G L; Williamson, D L; Cederwall, R T; Boyle, J S; Fiorino, M; Hnilo, J J; Olson, J G; Xie, S; Yio, J J
2003-11-21
To significantly improve the simulation of climate by general circulation models (GCMs), systematic errors in representations of relevant processes must first be identified, and then reduced. This endeavor demands, in particular, that the GCM parameterizations of unresolved processes should be tested over a wide range of time scales, not just in climate simulations. Thus, a numerical weather prediction (NWP) methodology for evaluating model parameterizations and gaining insights into their behavior may prove useful, provied that suitable adaptations are made for implementation in climate GCMs. This method entails the generation of short-range weather forecasts by realistically initialized climate GCM, and the application of six-hourly NWP analyses and observations of parameterized variables to evaluate these forecasts. The behavior of the parameterizations in such a weather-forecasting framework can provide insights on how these schemes might be improved, and modified parameterizations then can be similarly tested. In order to further this method for evaluating and analyzing parameterizations in climate GCMs, the USDOE is funding a joint venture of its Climate Change Prediction Program (CCPP) and Atmospheric Radiation Measurement (ARM) Program: the CCPP-ARM Parameterization Testbed (CAPT). This article elaborates the scientific rationale for CAPT, discusses technical aspects of its methodology, and presents examples of its implementation in a representative climate GCM. Numerical weather prediction methods show promise for improving parameterizations in climate GCMs.
2. Scatter correction for cone-beam computed tomography using self-adaptive scatter kernel superposition
Xie, Shi-Peng; Luo, Li-Min
2012-06-01
The authors propose a combined scatter reduction and correction method to improve image quality in cone beam computed tomography (CBCT). The scatter kernel superposition (SKS) method has been used occasionally in previous studies. However, this method differs in that a scatter detecting blocker (SDB) was used between the X-ray source and the tested object to model the self-adaptive scatter kernel. This study first evaluates the scatter kernel parameters using the SDB, and then isolates the scatter distribution based on the SKS. The quality of image can be improved by removing the scatter distribution. The results show that the method can effectively reduce the scatter artifacts, and increase the image quality. Our approach increases the image contrast and reduces the magnitude of cupping. The accuracy of the SKS technique can be significantly improved in our method by using a self-adaptive scatter kernel. This method is computationally efficient, easy to implement, and provides scatter correction using a single scan acquisition.
3. Impact of ice crystal habit on the parameterization of cloud microphysical properties when using 94ghz polarimetric scanning cloud radar during STORMVEX
Hammonds, Kevin Don
Through the analysis of scanning polarimetric W-band cloud radar data collected during STORMVEX, an algorithm has been developed to both identify and parameterize various ice crystal habits present within mixed-phase clouds. Armed with a unique dataset, the development of the algorithm took advantage of a slant 45° linear depolarization ratio (SLDR) measurement that was made as a function of the radar elevation angle when in range height indicator (RHI) scanning mode. This measurement technique proved to be invaluable in that it limited the influence of the particle's maximum dimension on the measured depolarization, which instead became more a function of the ice particle's shape. Validated through in situ measurements; pristine dendrites, lightly rimed dendrites, rimed stellar crystals, aggregates of dendrites, columns, and graupel particles were identified and matched with specific SLDR signatures. With a known ice particle habit and SLDR signature, the ice particle habit identification segment of the newly developed algorithm was then applied to the entire dataset consisting of 38,190 individual scans, in order to identify ice particle habits at a combined 849,745 range-heights and scanning angles. Through this analysis and the use of a chi-square test statistic, the predominant ice particle habit could be determined. Of primary interest in this study were the parameterizations of the ice particle mass and radar backscatter cross section. Through the modeling of the chosen ice particle habit as an oblate spheroid, these parameterizations were carried out in part by relying on previously published empirical studies as well as T-matrix scattering calculations of oblate spheroids composed of an ice/air mixture. Due to the computational expense of T-matrix calculations, however, a new T-matrix scaling factor was derived from the Clausius-Mossotti relation, which relates the refractive index of a material to its polarizability. With this scaling factor, new T
4. An Empirical Cumulus Parameterization Scheme for a Global Spectral Model
NASA Technical Reports Server (NTRS)
Rajendran, K.; Krishnamurti, T. N.; Misra, V.; Tao, W.-K.
2004-01-01
Realistic vertical heating and drying profiles in a cumulus scheme is important for obtaining accurate weather forecasts. A new empirical cumulus parameterization scheme based on a procedure to improve the vertical distribution of heating and moistening over the tropics is developed. The empirical cumulus parameterization scheme (ECPS) utilizes profiles of Tropical Rainfall Measuring Mission (TRMM) based heating and moistening derived from the European Centre for Medium- Range Weather Forecasts (ECMWF) analysis. A dimension reduction technique through rotated principal component analysis (RPCA) is performed on the vertical profiles of heating (Q1) and drying (Q2) over the convective regions of the tropics, to obtain the dominant modes of variability. Analysis suggests that most of the variance associated with the observed profiles can be explained by retaining the first three modes. The ECPS then applies a statistical approach in which Q1 and Q2 are expressed as a linear combination of the first three dominant principal components which distinctly explain variance in the troposphere as a function of the prevalent large-scale dynamics. The principal component (PC) score which quantifies the contribution of each PC to the corresponding loading profile is estimated through a multiple screening regression method which yields the PC score as a function of the large-scale variables. The profiles of Q1 and Q2 thus obtained are found to match well with the observed profiles. The impact of the ECPS is investigated in a series of short range (1-3 day) prediction experiments using the Florida State University global spectral model (FSUGSM, T126L14). Comparisons between short range ECPS forecasts and those with the modified Kuo scheme show a very marked improvement in the skill in ECPS forecasts. This improvement in the forecast skill with ECPS emphasizes the importance of incorporating realistic vertical distributions of heating and drying in the model cumulus scheme. This
5. Accuracy of cuticular resistance parameterizations in ammonia dry deposition models
Schrader, Frederik; Brümmer, Christian; Richter, Undine; Fléchard, Chris; Wichink Kruit, Roy; Erisman, Jan Willem
2016-04-01
Accurate representation of total reactive nitrogen (Nr) exchange between ecosystems and the atmosphere is a crucial part of modern air quality models. However, bi-directional exchange of ammonia (NH3), the dominant Nr species in agricultural landscapes, still poses a major source of uncertainty in these models, where especially the treatment of non-stomatal pathways (e.g. exchange with wet leaf surfaces or the ground layer) can be challenging. While complex dynamic leaf surface chemistry models have been shown to successfully reproduce measured ammonia fluxes on the field scale, computational restraints and the lack of necessary input data have so far limited their application in larger scale simulations. A variety of different approaches to modelling dry deposition to leaf surfaces with simplified steady-state parameterizations have therefore arisen in the recent literature. We present a performance assessment of selected cuticular resistance parameterizations by comparing them with ammonia deposition measurements by means of eddy covariance (EC) and the aerodynamic gradient method (AGM) at a number of semi-natural and grassland sites in Europe. First results indicate that using a state-of-the-art uni-directional approach tends to overestimate and using a bi-directional cuticular compensation point approach tends to underestimate cuticular resistance in some cases, consequently leading to systematic errors in the resulting flux estimates. Using the uni-directional model, situations where low ratios of total atmospheric acids to NH3 concentration occur lead to fairly high minimum cuticular resistances, limiting predicted downward fluxes in conditions usually favouring deposition. On the other hand, the bi-directional model used here features a seasonal cycle of external leaf surface emission potentials that can lead to comparably low effective resistance estimates under warm and wet conditions, when in practice an expected increase in the compensation point due to
6. Physically-Based Parameterization of Frozen Ground Processes in Watershed Runoff Modeling
Koren, V. I.
2004-05-01
parameters were used at all sites. Solid and liquid soil moisture contents, and soil temperature at five layers were simulated for 3-5 years. Test results suggest that a conceptual representation of soil moisture fluxes combined with a physically-based heat transfer model provides reasonable simulations of soil temperature for the entire soil profile. Ignoring soil moisture phase transitions can lead to significant biases of soil temperature. Simulated soil moisture states also agree well with measurements for the research watershed for an 18-year period. A second set of tests was performed for a few river basins when only outlet hydrographs were evaluated. A priori water balance model parameters were adjusted using automatic or manual calibration. Simulated and observed hydrographs agree better when the frozen ground parameterization was added specifically during transition periods from spring to summer. More importantly, the un-calibrated model with the frozen ground component outperforms the un-calibrated model with no frozen ground component for all tested basins. Spring floods analysis suggests also that it is impossible to remove runoff biases without modification of frozen ground hydraulic properties.
7. Frozen soil parameterization in a distributed biosphere hydrological model
Wang, L.; Koike, T.; Yang, K.; Jin, R.; Li, H.
2009-11-01
In this study, a frozen soil parameterization has been modified and incorporated into a distributed biosphere hydrological model (WEB-DHM). The WEB-DHM with the frozen scheme was then rigorously evaluated in a small cold area, the Binngou watershed, against the in-situ observations from the WATER (Watershed Allied Telemetry Experimental Research). In the summer 2008, land surface parameters were optimized using the observed surface radiation fluxes and the soil temperature profile at the Dadongshu-Yakou (DY) station in July; and then soil hydraulic parameters were obtained by the calibration of the July soil moisture profile at the DY station and by the calibration of the discharges at the basin outlet in July and August that covers the annual largest flood peak of 2008. The calibrated WEB-DHM with the frozen scheme was then used for a yearlong simulation from 21 November 2007 to 20 November 2008, to check its performance in cold seasons. Results showed that the WEB-DHM with the frozen scheme has given much better performance than the WEB-DHM without the frozen scheme, in the simulations of soil moisture profile at the DY station and the discharges at the basin outlet in the yearlong simulation.
8. Frozen soil parameterization in a distributed biosphere hydrological model
Wang, L.; Koike, T.; Yang, K.; Jin, R.; Li, H.
2010-03-01
In this study, a frozen soil parameterization has been modified and incorporated into a distributed biosphere hydrological model (WEB-DHM). The WEB-DHM with the frozen scheme was then rigorously evaluated in a small cold area, the Binngou watershed, against the in-situ observations from the WATER (Watershed Allied Telemetry Experimental Research). First, by using the original WEB-DHM without the frozen scheme, the land surface parameters and two van Genuchten parameters were optimized using the observed surface radiation fluxes and the soil moistures at upper layers (5, 10 and 20 cm depths) at the DY station in July. Second, by using the WEB-DHM with the frozen scheme, two frozen soil parameters were calibrated using the observed soil temperature at 5 cm depth at the DY station from 21 November 2007 to 20 April 2008; while the other soil hydraulic parameters were optimized by the calibration of the discharges at the basin outlet in July and August that covers the annual largest flood peak in 2008. With these calibrated parameters, the WEB-DHM with the frozen scheme was then used for a yearlong validation from 21 November 2007 to 20 November 2008. Results showed that the WEB-DHM with the frozen scheme has given much better performance than the WEB-DHM without the frozen scheme, in the simulations of soil moisture profile at the cold regions catchment and the discharges at the basin outlet in the yearlong simulation.
9. Effective parameterizations of three nonwetting phase relative permeability models
Yang, Zhenlei; Mohanty, Binayak P.
2015-08-01
Describing convective nonwetting phase flow in unsaturated porous media requires knowledge of the nonwetting phase relative permeability. This study was conducted to formulate and derive a generalized expression for the nonwetting phase relative permeability via combining with the Kosugi water retention function. This generalized formulation is then used to flexibly investigate the Burdine, Mualem, and Alexander and Skaggs models' prediction accuracy for relative nonwetting phase permeability. The model and data comparison results show that these three permeability models, if used in their original form, but applied to the nonwetting phase, could not predict the experimental data well. The optimum pore tortuosity and connectivity value is thus obtained for the improved prediction of relative nonwetting phase permeability. As a result, the effective parameterization of (α,β,η) parameters in the modified Burdine, modified Mualem, and modified Alexander and Skaggs permeability models were found to be (2.5, 2, 1), (2, 1, 2), and (2.5, 1, 1), respectively. These three suggested models display the highest accuracy among the nine relative permeability models investigated in this study. However, the corresponding discontinuous nonwetting phase and the liquid film flow should be accounted for in future for the improved prediction of nonwetting phase relative permeability at very high and very low water saturation range, respectively.
10. Specialized Knowledge Representation and the Parameterization of Context.
PubMed
Faber, Pamela; León-Araúz, Pilar
2016-01-01
Though instrumental in numerous disciplines, context has no universally accepted definition. In specialized knowledge resources it is timely and necessary to parameterize context with a view to more effectively facilitating knowledge representation, understanding, and acquisition, the main aims of terminological knowledge bases. This entails distinguishing different types of context as well as how they interact with each other. This is not a simple objective to achieve despite the fact that specialized discourse does not have as many contextual variables as those in general language (i.e., figurative meaning, irony, etc.). Even in specialized text, context is an extremely complex concept. In fact, contextual information can be specified in terms of scope or according to the type of information conveyed. It can be a textual excerpt or a whole document; a pragmatic convention or a whole culture; a concrete situation or a prototypical scenario. Although these versions of context are useful for the users of terminological resources, such resources rarely support context modeling. In this paper, we propose a taxonomy of context primarily based on scope (local and global) and further divided into syntactic, semantic, and pragmatic facets. These facets cover the specification of different types of terminological information, such as predicate-argument structure, collocations, semantic relations, term variants, grammatical and lexical cohesion, communicative situations, subject fields, and cultures. PMID:26941674
11. Sensitivity and Uncertainty in Detonation Shock Dynamics Parameterization
Chiquete, Carlos; Short, Mark; Jackson, Scott
2013-06-01
Detonation shock dynamics (DSD) is the timing component of an advanced programmed burn model of detonation propagation in high explosives (HE). In DSD theory, the detonation-driving zone is replaced with a propagating surface in which the surface normal velocity is a function of the local surface curvature, the so-called Dn - κ relation for the HE. This relation is calibrated by assuming a functional form relating Dn and κ, and then fitting the function parameters via minimization of a weighted error function of residuals based on shock-shape curves and a diameter effect curve. In general, for a given HE, the greater the available shock-shape data at different rate-stick radii, the less the uncertainty in the DSD fit. For a wide range of HEs, however, no shock shape data is available, and DSD calibrations must be based on diameter effect data alone. With this limited data, potentially large variations in the DSD parameters can occur that fit the diameter effect curve to within a given residual error. We explore uncertainty issues in DSD parameterization when limited calibration data is available and the implications of the resulting sensitivities in timing, highlighting differences between ideal, insensitive and non-ideal HEs such as Cyclotol, IMX-104 and ANFO.
12. Fire Detection and Parameterization with Msg-Seviri Sensor
Calle, A.; Casanova, J. L.; Moclán, C.; Romo, A.; Fraile, S.
2006-08-01
The detection of forest fires and the determination of their parameters has been a task usually carried out by polar-orbit sensors, AVHRR (A)ATSR, BIRD and MODIS mainly. However, their time resolution prevents them from operating in real time. On the other hand, the new geostationary sensors have very appropriate capacities for the observation of the Earth and for the monitoring of forest fires, as is being proved. GOES, MSG and MTSAT are already operative with time resolutions less than 30 minutes, 15 minutes for MSG, objective of this paper, and they have led the international community to think that the global observation network in real time may become a reality. The implementation of this network is the aim of the Global Observations of Forest Cover and Land Cover Dynamics (GOFC/GOLD) FIRE Mapping and Monitoring program, focused internationally on taking decisions concerning the research of the Global Change. In this paper, the operation in real time by the MSG- SEVIRI sensor over the Iberian Peninsula is carried out. Its capacity to detect hot forest fires smaller than 0.3 ha in Mediterranean latitudes has been analysed. Concerning fire parameterization two topics are analysed too: the possibility to use SWIR spectral channel in order to replace MIR in saturation situations and dependence of fire parameters versus the problem of resampling pixels.
13. Specialized Knowledge Representation and the Parameterization of Context
PubMed Central
Faber, Pamela
2016-01-01
Though instrumental in numerous disciplines, context has no universally accepted definition. In specialized knowledge resources it is timely and necessary to parameterize context with a view to more effectively facilitating knowledge representation, understanding, and acquisition, the main aims of terminological knowledge bases. This entails distinguishing different types of context as well as how they interact with each other. This is not a simple objective to achieve despite the fact that specialized discourse does not have as many contextual variables as those in general language (i.e., figurative meaning, irony, etc.). Even in specialized text, context is an extremely complex concept. In fact, contextual information can be specified in terms of scope or according to the type of information conveyed. It can be a textual excerpt or a whole document; a pragmatic convention or a whole culture; a concrete situation or a prototypical scenario. Although these versions of context are useful for the users of terminological resources, such resources rarely support context modeling. In this paper, we propose a taxonomy of context primarily based on scope (local and global) and further divided into syntactic, semantic, and pragmatic facets. These facets cover the specification of different types of terminological information, such as predicate-argument structure, collocations, semantic relations, term variants, grammatical and lexical cohesion, communicative situations, subject fields, and cultures. PMID:26941674
14. Population models for passerine birds: structure, parameterization, and analysis
USGS Publications Warehouse
Noon, B.R.; Sauer, J.R.; McCullough, D.R.; Barrett, R.H.
1992-01-01
Population models have great potential as management tools, as they use infonnation about the life history of a species to summarize estimates of fecundity and survival into a description of population change. Models provide a framework for projecting future populations, determining the effects of management decisions on future population dynamics, evaluating extinction probabilities, and addressing a variety of questions of ecological and evolutionary interest. Even when insufficient information exists to allow complete identification of the model, the modelling procedure is useful because it forces the investigator to consider the life history of the species when determining what parameters should be estimated from field studies and provides a context for evaluating the relative importance of demographic parameters. Models have been little used in the study of the population dynamics of passerine birds because of: (1) widespread misunderstandings of the model structures and parameterizations, (2) a lack of knowledge of life histories of many species, (3) difficulties in obtaining statistically reliable estimates of demographic parameters for most passerine species, and (4) confusion about functional relationships among demographic parameters. As a result, studies of passerine demography are often designed inappropriately and fail to provide essential data. We review appropriate models for passerine bird populations and illustrate their possible uses in evaluating the effects of management or other environmental influences on population dynamics. We identify environmental influences on population dynamics. We identify parameters that must be estimated from field data, briefly review existing statistical methods for obtaining valid estimates, and evaluate the present status of knowledge of these parameters.
15. Parameterizations in high resolution isopycnal wind-driven ocean models
Jensen, T. G.; Randall, D. A.
1994-01-01
For the Computer Hardware Advanced Mathematics and Model Physics (CHAMMP) project, developing a new multilayer ocean model, based on the hydrodynamic FSU Indian Ocean model was proposed. The new model will include prognostic temperature and salinity and will be coded for massively parallel machines. Other specific objectives for the proposed research were to: incorporate a oceanic mixed layer on top of the isopycnal deep layers; implement positive definite scheme for advection; determine effects of islands on large scale flow; and investigate lateral boundary conditions for boundary layer currents. The mixed layer model is proposed to be of a bulk type with prognostic equations for temperature and salinity. Development of parallel code will be done in cooperation with other CHAMMP participants, mainly the ocean modelling group at LANL. The main objective is model development, while the application is to determine the influence and parameterization of narrow flows along continents and through chains of small islands on the large scale oceanic circulation. Test runs with artificial wind stress and heat flux will be used to determine model stability, performance, and optimization for the new model configuration. Tests will include western boundary currents, coastal upwelling, and equatorial dynamics. This report discusses project progress for period January 1, 1993 through December 31, 1993.
16. Systematic multiscale parameterization of heterogeneous elastic network models of proteins.
PubMed
Lyman, Edward; Pfaendtner, Jim; Voth, Gregory A
2008-11-01
We present a method to parameterize heterogeneous elastic network models (heteroENMs) of proteins to reproduce the fluctuations observed in atomistic simulations. Because it is based on atomistic simulation, our method allows the development of elastic coarse-grained models of proteins under different conditions or in different environments. The method is simple and applicable to models at any level of coarse-graining. We validated the method in three systems. First, we computed the persistence length of ADP-bound F-actin, using a heteroENM model. The value of 6.1 +/- 1.6 microm is consistent with the experimentally measured value of 9.0 +/- 0.5 microm. We then compared our method to a uniform elastic network model and a realistic extension algorithm via covariance Hessian (REACH) model of carboxy myoglobin, and found that the heteroENM method more accurately predicted mean-square fluctuations of alpha-carbon atoms. Finally, we showed that the method captures critical differences in effective harmonic interactions for coarse-grained models of the N-terminal Bin/amphiphysin/Rvs (N-BAR) domain of amphiphysin, by building models of N-BAR both bound to a membrane and free in solution.
17. Factors influencing the parameterization of tropical anvils within GCMs
SciTech Connect
1994-03-01
The overall goal of this project is to improve the representation of anvil clouds and their effects in general circulation models (GCMs). We have concentrated on an important portion of the overall goal; the evolution of cumulus-generated anvil clouds and their effects on the large-scale environment. Because of the large range of spatial and temporal scales involved, we have been using a multi-scale approach. For the early-time generation and development of the citrus anvil we are using a cloud-scale model with a horizontal resolution of 1-2 kilometers, while for the transport of anvils by the large-scale flow we are using a mesoscale model with a horizontal resolution of 10-40 kilometers. The eventual goal is to use the information obtained from these simulations, together with available observations to develop an improved cloud parameterization for use in GCMS. The cloud-scale simulation of a midlatitude squall line case and the mesoscale study of a tropical anvil using an anvil generator were presented at the last ARM science team meeting. This paper concentrates on the cloud-scale study of a tropical squall line. Results are compared with its midlatitude counterparts to further our understanding of the formation mechanism of anvil clouds and the sensitivity of radiation to their optical properties.
18. Radiation Parameterization for Three-Dimensional Inhomogeneous Cirrus Clouds Applied to ARM Data and Climate Models
SciTech Connect
Kuo-Nan Liou
2003-12-29
19. Winter QPF Sensitivities to Snow Parameterizations and Comparisons to NASA CloudSat Observations
NASA Technical Reports Server (NTRS)
Molthan, Andrew; Haynes, John M.; Jedlovec, Gary J.; Lapenta, William M.
2009-01-01
Steady increases in computing power have allowed for numerical weather prediction models to be initialized and run at high spatial resolution, permitting a transition from larger scale parameterizations of the effects of clouds and precipitation to the simulation of specific microphysical processes and hydrometeor size distributions. Although still relatively coarse in comparison to true cloud resolving models, these high resolution forecasts (on the order of 4 km or less) have demonstrated value in the prediction of severe storm mode and evolution and are being explored for use in winter weather events . Several single-moment bulk water microphysics schemes are available within the latest release of the Weather Research and Forecast (WRF) model suite, including the NASA Goddard Cumulus Ensemble, which incorporate some assumptions in the size distribution of a small number of hydrometeor classes in order to predict their evolution, advection and precipitation within the forecast domain. Although many of these schemes produce similar forecasts of events on the synoptic scale, there are often significant details regarding precipitation and cloud cover, as well as the distribution of water mass among the constituent hydrometeor classes. Unfortunately, validating data for cloud resolving model simulations are sparse. Field campaigns require in-cloud measurements of hydrometeors from aircraft in coordination with extensive and coincident ground based measurements. Radar remote sensing is utilized to detect the spatial coverage and structure of precipitation. Here, two radar systems characterize the structure of winter precipitation for comparison to equivalent features within a forecast model: a 3 GHz, Weather Surveillance Radar-1988 Doppler (WSR-88D) based in Omaha, Nebraska, and the 94 GHz NASA CloudSat Cloud Profiling Radar, a spaceborne instrument and member of the afternoon or "A-Train" of polar orbiting satellites tasked with cataloguing global cloud
20. On testing two major cumulus parameterization schemes using the CSU Regional Atmospheric Modeling System
SciTech Connect
Kao, C.Y.J.; Bossert, J.E.; Winterkamp, J.; Lai, C.C.
1993-10-01
One of the objectives of the DOE ARM Program is to improve the parameterization of clouds in general circulation models (GCMs). The approach taken in this research is two fold. We first examine the behavior of cumulus parameterization schemes by comparing their performance against the results from explicit cloud simulations with state-of-the-art microphysics. This is conducted in a two-dimensional (2-D) configuration of an idealized convective system. We then apply the cumulus parameterization schemes to realistic three-dimensional (3-D) simulations over the western US for a case with an enormous amount of convection in an extended period of five days. In the 2-D idealized tests, cloud effects are parameterized in the parameterization cases with a coarse resolution, whereas each cloud is explicitly resolved by the microphysics cases with a much finer resolution. Thus, the capability of the parameterization schemes in reproducing the growth and life cycle of a convective system can then be evaluated. These 2-D tests will form the basis for further 3-D realistic simulations which have the model resolution equivalent to that of the next generation of GCMs. Two cumulus parameterizations are used in this research: the Arakawa-Schubert (A-S) scheme (Arakawa and Schubert, 1974) used in Kao and Ogura (1987) and the Kuo scheme (Kuo, 1974) used in Tremback (1990). The numerical model used in this research is the Regional Atmospheric Modeling System (RAMS) developed at Colorado State University (CSU).
1. Evaluation of Warm-Rain Microphysical Parameterizations in Cloudy Boundary Layer Transitions
Nelson, K.; Mechem, D. B.
2014-12-01
Common warm-rain microphysical parameterizations used for marine boundary layer (MBL) clouds are either tuned for specific cloud types (e.g., the Khairoutdinov and Kogan 2000 parameterization, "KK2000") or are altogether ill-posed (Kessler 1969). An ideal microphysical parameterization should be "unified" in the sense of being suitable across MBL cloud regimes that include stratocumulus, cumulus rising into stratocumulus, and shallow trade cumulus. The recent parameterization of Kogan (2013, "K2013") was formulated for shallow cumulus but has been shown in a large-eddy simulation environment to work quite well for stratocumulus as well. We report on our efforts to implement and test this parameterization into a regional forecast model (NRL COAMPS). Results from K2013 and KK2000 are compared with the operational Kessler parameterization for a 5-day period of the VOCALS-REx field campaign, which took place over the southeast Pacific. We focus on both the relative performance of the three parameterizations and also on how they compare to the VOCALS-REx observations from the NOAA R/V Ronald H. Brown, in particular estimates of boundary-layer depth, liquid water path (LWP), cloud base, and area-mean precipitation rate obtained from C-band radar.
2. A unified parameterization of clouds and turbulence using CLUBB and subcolumns in the Community Atmosphere Model
DOE PAGES
Thayer-Calder, K.; Gettelman, A.; Craig, C.; Goldhaber, S.; Bogenschutz, P. A.; Chen, C.-C.; Morrison, H.; Höft, J.; Raut, E.; Griffin, B. M.; et al
2015-12-01
Most global climate models parameterize separate cloud types using separate parameterizations. This approach has several disadvantages, including obscure interactions between parameterizations and inaccurate triggering of cumulus parameterizations. Alternatively, a unified cloud parameterization uses one equation set to represent all cloud types. Such cloud types include stratiform liquid and ice cloud, shallow convective cloud, and deep convective cloud. Vital to the success of a unified parameterization is a general interface between clouds and microphysics. One such interface involves drawing Monte Carlo samples of subgrid variability of temperature, water vapor, cloud liquid, and cloud ice, and feeding the sample points into amore » microphysics scheme. This study evaluates a unified cloud parameterization and a Monte Carlo microphysics interface that has been implemented in the Community Atmosphere Model (CAM) version 5.3. Model computational expense is estimated, and sensitivity to the number of subcolumns is investigated. Results describing the mean climate and tropical variability from global simulations are presented. The new model shows a degradation in precipitation skill but improvements in shortwave cloud forcing, liquid water path, long-wave cloud forcing, precipitable water, and tropical wave simulation.« less
3. A unified parameterization of clouds and turbulence using CLUBB and subcolumns in the Community Atmosphere Model
DOE PAGES
Thayer-Calder, K.; Gettelman, A.; Craig, C.; Goldhaber, S.; Bogenschutz, P. A.; Chen, C.-C.; Morrison, H.; Höft, J.; Raut, E.; Griffin, B. M.; et al
2015-06-30
Most global climate models parameterize separate cloud types using separate parameterizations. This approach has several disadvantages, including obscure interactions between parameterizations and inaccurate triggering of cumulus parameterizations. Alternatively, a unified cloud parameterization uses one equation set to represent all cloud types. Such cloud types include stratiform liquid and ice cloud, shallow convective cloud, and deep convective cloud. Vital to the success of a unified parameterization is a general interface between clouds and microphysics. One such interface involves drawing Monte Carlo samples of subgrid variability of temperature, water vapor, cloud liquid, and cloud ice, and feeding the sample points into amore » microphysics scheme. This study evaluates a unified cloud parameterization and a Monte Carlo microphysics interface that has been implemented in the Community Atmosphere Model (CAM) version 5.3. Results describing the mean climate and tropical variability from global simulations are presented. The new model shows a degradation in precipitation skill but improvements in short-wave cloud forcing, liquid water path, long-wave cloud forcing, precipitable water, and tropical wave simulation. Also presented are estimations of computational expense and investigation of sensitivity to number of subcolumns.« less
4. Preliminary Assessment of Mercury Atmosphere-Surface Exchange Parameterizations for Incorporation into Chemical Transport Models
Khan, T.; Agnan, Y.; Obrist, D.; Selin, N. E.; Urban, N. R.; Wu, S.; Perlinger, J. A.
2015-12-01
Inadequate representation of process-based mechanisms of exchange behavior of elemental mercury (Hg0) and decoupled treatment of deposition and emission are two major limitations of parameterizations of atmosphere-surface exchange flux commonly incorporated into chemical transport models (CTMs). Of nineteen CTMs for Hg0 exchange we reviewed (ten global, nine regional), eight global and seven regional models have decoupled treatment of Hg0 deposition and emission, two global models include no parameterization to account for emission, and the remaining two regional models include coupled deposition and emission parameterizations (i.e., net atmosphere-surface exchange). The performance of atmosphere-surface exchange parameterizations in CTMs depends on parameterization uncertainty (in terms of both accuracy and precision) and feasibility of implementation. We provide a comparison of the performance of three available parameterizations of net atmosphere-surface exchange. To evaluate parameterization accuracy, we compare predicted exchange fluxes to field measurements conducted over a variety of surfaces compiled in a recently developed global database of terrestrial Hg0 surface-atmosphere exchange flux measurements. To assess precision, we estimate the sensitivity of predicted fluxes to the imprecision in parameter input values, and compare this sensitivity to that derived from analysis of the global Hg0 flux database. Feasibility of implementation is evaluated according to the availability of input parameters, computational requirements, and the adequacy of uncertainty representation. Based on this assessment, we provide suggestions for improved treatment of Hg0 net exchange processes in CTMs.
5. [Formula: see text] regularity properties of singular parameterizations in isogeometric analysis.
PubMed
Takacs, T; Jüttler, B
2012-11-01
Isogeometric analysis (IGA) is a numerical simulation method which is directly based on the NURBS-based representation of CAD models. It exploits the tensor-product structure of 2- or 3-dimensional NURBS objects to parameterize the physical domain. Hence the physical domain is parameterized with respect to a rectangle or to a cube. Consequently, singularly parameterized NURBS surfaces and NURBS volumes are needed in order to represent non-quadrangular or non-hexahedral domains without splitting, thereby producing a very compact and convenient representation. The Galerkin projection introduces finite-dimensional spaces of test functions in the weak formulation of partial differential equations. In particular, the test functions used in isogeometric analysis are obtained by composing the inverse of the domain parameterization with the NURBS basis functions. In the case of singular parameterizations, however, some of the resulting test functions do not necessarily fulfill the required regularity properties. Consequently, numerical methods for the solution of partial differential equations cannot be applied properly. We discuss the regularity properties of the test functions. For one- and two-dimensional domains we consider several important classes of singularities of NURBS parameterizations. For specific cases we derive additional conditions which guarantee the regularity of the test functions. In addition we present a modification scheme for the discretized function space in case of insufficient regularity. It is also shown how these results can be applied for computational domains in higher dimensions that can be parameterized via sweeping.
6. Evaluating Parameterizations in General Circulation Models: Climate Simulation Meets Weather Prediction
SciTech Connect
Phillips, T J; Potter, G L; Williamson, D L; Cederwall, R T; Boyle, J S; Fiorino, M; Hnilo, J J; Olson, J G; Xie, S; Yio, J J
2004-05-06
To significantly improve the simulation of climate by general circulation models (GCMs), systematic errors in representations of relevant processes must first be identified, and then reduced. This endeavor demands that the GCM parameterizations of unresolved processes, in particular, should be tested over a wide range of time scales, not just in climate simulations. Thus, a numerical weather prediction (NWP) methodology for evaluating model parameterizations and gaining insights into their behavior may prove useful, provided that suitable adaptations are made for implementation in climate GCMs. This method entails the generation of short-range weather forecasts by a realistically initialized climate GCM, and the application of six-hourly NWP analyses and observations of parameterized variables to evaluate these forecasts. The behavior of the parameterizations in such a weather-forecasting framework can provide insights on how these schemes might be improved, and modified parameterizations then can be tested in the same framework. In order to further this method for evaluating and analyzing parameterizations in climate GCMs, the U.S. Department of Energy is funding a joint venture of its Climate Change Prediction Program (CCPP) and Atmospheric Radiation Measurement (ARM) Program: the CCPP-ARM Parameterization Testbed (CAPT). This article elaborates the scientific rationale for CAPT, discusses technical aspects of its methodology, and presents examples of its implementation in a representative climate GCM.
7. A unified parameterization of clouds and turbulence using CLUBB and subcolumns in the Community Atmosphere Model
Thayer-Calder, K.; Gettelman, A.; Craig, C.; Goldhaber, S.; Bogenschutz, P. A.; Chen, C.-C.; Morrison, H.; Höft, J.; Raut, E.; Griffin, B. M.; Weber, J. K.; Larson, V. E.; Wyant, M. C.; Wang, M.; Guo, Z.; Ghan, S. J.
2015-12-01
Most global climate models parameterize separate cloud types using separate parameterizations. This approach has several disadvantages, including obscure interactions between parameterizations and inaccurate triggering of cumulus parameterizations. Alternatively, a unified cloud parameterization uses one equation set to represent all cloud types. Such cloud types include stratiform liquid and ice cloud, shallow convective cloud, and deep convective cloud. Vital to the success of a unified parameterization is a general interface between clouds and microphysics. One such interface involves drawing Monte Carlo samples of subgrid variability of temperature, water vapor, cloud liquid, and cloud ice, and feeding the sample points into a microphysics scheme. This study evaluates a unified cloud parameterization and a Monte Carlo microphysics interface that has been implemented in the Community Atmosphere Model (CAM) version 5.3. Model computational expense is estimated, and sensitivity to the number of subcolumns is investigated. Results describing the mean climate and tropical variability from global simulations are presented. The new model shows a degradation in precipitation skill but improvements in shortwave cloud forcing, liquid water path, long-wave cloud forcing, precipitable water, and tropical wave simulation.
8. A unified parameterization of clouds and turbulence using CLUBB and subcolumns in the Community Atmosphere Model
Thayer-Calder, K.; Gettelman, A.; Craig, C.; Goldhaber, S.; Bogenschutz, P. A.; Chen, C.-C.; Morrison, H.; Höft, J.; Raut, E.; Griffin, B. M.; Weber, J. K.; Larson, V. E.; Wyant, M. C.; Wang, M.; Guo, Z.; Ghan, S. J.
2015-06-01
Most global climate models parameterize separate cloud types using separate parameterizations. This approach has several disadvantages, including obscure interactions between parameterizations and inaccurate triggering of cumulus parameterizations. Alternatively, a unified cloud parameterization uses one equation set to represent all cloud types. Such cloud types include stratiform liquid and ice cloud, shallow convective cloud, and deep convective cloud. Vital to the success of a unified parameterization is a general interface between clouds and microphysics. One such interface involves drawing Monte Carlo samples of subgrid variability of temperature, water vapor, cloud liquid, and cloud ice, and feeding the sample points into a microphysics scheme. This study evaluates a unified cloud parameterization and a Monte Carlo microphysics interface that has been implemented in the Community Atmosphere Model (CAM) version 5.3. Results describing the mean climate and tropical variability from global simulations are presented. The new model shows a degradation in precipitation skill but improvements in short-wave cloud forcing, liquid water path, long-wave cloud forcing, precipitable water, and tropical wave simulation. Also presented are estimations of computational expense and investigation of sensitivity to number of subcolumns.
SciTech Connect
Sorg, T.J.
1991-01-01
The U.S. Environmental Protection Agency proposed new and revised regulations on radionuclide contaminants in drinking water in June 1991. During the 1980's, the Drinking Water Research Division, USEPA conducted a research program to evaluate various technologies to remove radium, uranium and radon from drinking water. The research consisted of laboratory and field studies conducted by USEPA, universities and consultants. The paper summarizes the results of the most significant projects completed. General information is also presented on the general chemistry of the three radionuclides. The information presented indicates that the most practical treatment methods for radium are ion exchange and lime-soda softening and reverse osmosis. The methods tested for radon are aeration and granular activated carbon and the methods for uranium are anion exchange and reverse osmosis.
10. Cross-Section Parameterizations for Pion and Nucleon Production From Negative Pion-Proton Collisions
NASA Technical Reports Server (NTRS)
Norbury, John W.; Blattnig, Steve R.; Norman, Ryan; Tripathi, R. K.
2002-01-01
Ranft has provided parameterizations of Lorentz invariant differential cross sections for pion and nucleon production in pion-proton collisions that are compared to some recent data. The Ranft parameterizations are then numerically integrated to form spectral and total cross sections. These numerical integrations are further parameterized to provide formula for spectral and total cross sections suitable for use in radiation transport codes. The reactions analyzed are for charged pions in the initial state and both charged and neutral pions in the final state.
11. Improvement of the GEOS-5 AGCM upon Updating the Air-Sea Roughness Parameterization
NASA Technical Reports Server (NTRS)
Garfinkel, C. I.; Molod, A.; Oman, L. D.; Song, I.-S.
2011-01-01
The impact of an air-sea roughness parameterization over the ocean that more closely matches recent observations of air-sea exchange is examined in the NASA Goddard Earth Observing System, version 5 (GEOS-5) atmospheric general circulation model. Surface wind biases in the GEOS-5 AGCM are decreased by up to 1.2m/s. The new parameterization also has implications aloft as improvements extend into the stratosphere. Many other GCMs (both for operational weather forecasting and climate) use a similar class of parameterization for their air-sea roughness scheme. We therefore expect that results from GEOS-5 are relevant to other models as well.
12. Improvement of the GEOS-5 AGCM upon updating the air-sea roughness parameterization
Garfinkel, C. I.; Molod, A. M.; Oman, L. D.; Song, I.-S.
2011-09-01
The impact of an air-sea roughness parameterization over the ocean that more closely matches recent observations of air-sea exchange is examined in the NASA Goddard Earth Observing System, version 5 (GEOS-5) atmospheric general circulation model. Surface wind biases in the GEOS-5 AGCM are decreased by up to 1.2m/s. The new parameterization also has implications aloft as improvements extend into the stratosphere. Many other GCMs (both for operational weather forecasting and climate) use a similar class of parameterization for their air-sea roughness scheme. We therefore expect that results from GEOS-5 are relevant to other models as well.
13. Towards a parameterization of convective wind gusts in Sahel
Largeron, Yann; Guichard, Françoise; Bouniol, Dominique; Couvreux, Fleur; Birch, Cathryn; Beucher, Florent
2014-05-01
] who focused on the wet tropical Pacific region, and linked wind gusts to convective precipitation rates alone, here, we also analyse the subgrid wind distribution during convective events, and quantify the statistical moments (variance, skewness and kurtosis) in terms of mean wind speed and convective indexes such as DCAPE. Next step of the work will be to formulate a parameterization of the cold pool convective gust from those probability density functions and analytical formulaes obtained from basic energy budget models. References : [Carslaw et al., 2010] A review of natural aerosol interactions and feedbacks within the earth system. Atmospheric Chemistry and Physics, 10(4):1701{1737. [Engelstaedter et al., 2006] North african dust emissions and transport. Earth-Science Reviews, 79(1):73{100. [Knippertz and Todd, 2012] Mineral dust aerosols over the sahara: Meteorological controls on emission and transport and implications for modeling. Reviews of Geophysics, 50(1). [Marsham et al., 2011] The importance of the representation of deep convection for modeled dust-generating winds over west africa during summer.Geophysical Research Letters, 38(16). [Marticorena and Bergametti, 1995] Modeling the atmospheric dust cycle: 1. design of a soil-derived dust emission scheme. Journal of Geophysical Research, 100(D8):16415{16. [Menut, 2008] Sensitivity of hourly saharan dust emissions to ncep and ecmwf modeled wind speed. Journal of Geophysical Research: Atmospheres (1984{2012), 113(D16). [Pierre et al., 2012] Impact of vegetation and soil moisture seasonal dynamics on dust emissions over the sahel. Journal of Geophysical Research: Atmospheres (1984{2012), 117(D6). [Redelsperger et al., 2000] A parameterization of mesoscale enhancement of surface fluxes for large-scale models. Journal of climate, 13(2):402{421.
14. Scattering from binary optics
NASA Technical Reports Server (NTRS)
Ricks, Douglas W.
1993-01-01
There are a number of sources of scattering in binary optics: etch depth errors, line edge errors, quantization errors, roughness, and the binary approximation to the ideal surface. These sources of scattering can be systematic (deterministic) or random. In this paper, scattering formulas for both systematic and random errors are derived using Fourier optics. These formulas can be used to explain the results of scattering measurements and computer simulations.
15. Approximations for photoelectron scattering
Fritzsche, V.
1989-04-01
The errors of several approximations in the theoretical approach of photoelectron scattering are systematically studied, in tungsten, for electron energies ranging from 10 to 1000 eV. The large inaccuracies of the plane-wave approximation (PWA) are substantially reduced by means of effective scattering amplitudes in the modified small-scattering-centre approximation (MSSCA). The reduced angular momentum expansion (RAME) is so accurate that it allows reliable calculations of multiple-scattering contributions for all the energies considered.
16. Cirrus cloud model parameterizations: Incorporating realistic ice particle generation
NASA Technical Reports Server (NTRS)
Sassen, Kenneth; Dodd, G. C.; Starr, David OC.
1990-01-01
Recent cirrus cloud modeling studies have involved the application of a time-dependent, two dimensional Eulerian model, with generalized cloud microphysical parameterizations drawn from experimental findings. For computing the ice versus vapor phase changes, the ice mass content is linked to the maintenance of a relative humidity with respect to ice (RHI) of 105 percent; ice growth occurs both with regard to the introduction of new particles and the growth of existing particles. In a simplified cloud model designed to investigate the basic role of various physical processes in the growth and maintenance of cirrus clouds, these parametric relations are justifiable. In comparison, the one dimensional cloud microphysical model recently applied to evaluating the nucleation and growth of ice crystals in cirrus clouds explicitly treated populations of haze and cloud droplets, and ice crystals. Although these two modeling approaches are clearly incompatible, the goal of the present numerical study is to develop a parametric treatment of new ice particle generation, on the basis of detailed microphysical model findings, for incorporation into improved cirrus growth models. For example, the relation between temperature and the relative humidity required to generate ice crystals from ammonium sulfate haze droplets, whose probability of freezing through the homogeneous nucleation mode are a combined function of time and droplet molality, volume, and temperature. As an example of this approach, the results of cloud microphysical simulations are presented showing the rather narrow domain in the temperature/humidity field where new ice crystals can be generated. The microphysical simulations point out the need for detailed CCN studies at cirrus altitudes and haze droplet measurements within cirrus clouds, but also suggest that a relatively simple treatment of ice particle generation, which includes cloud chemistry, can be incorporated into cirrus cloud growth.
17. Parameterization of a ruminant model of phosphorus digestion and metabolism.
PubMed
Feng, X; Knowlton, K F; Hanigan, M D
2015-10-01
The objective of the current work was to parameterize the digestive elements of the model of Hill et al. (2008) using data collected from animals that were ruminally, duodenally, and ileally cannulated, thereby providing a better understanding of the digestion and metabolism of P fractions in growing and lactating cattle. The model of Hill et al. (2008) was fitted and evaluated for adequacy using the data from 6 animal studies. We hypothesized that sufficient data would be available to estimate P digestion and metabolism parameters and that these parameters would be sufficient to derive P bioavailabilities of a range of feed ingredients. Inputs to the model were dry matter intake; total feed P concentration (fPtFd); phytate (Pp), organic (Po), and inorganic (Pi) P as fractions of total P (fPpPt, fPoPt, fPiPt); microbial growth; amount of Pi and Pp infused into the omasum or ileum; milk yield; and BW. The available data were sufficient to derive all model parameters of interest. The final model predicted that given 75 g/d of total P input, the total-tract digestibility of P was 40.8%, Pp digestibility in the rumen was 92.4%, and in the total-tract was 94.7%. Blood P recycling to the rumen was a major source of Pi flow into the small intestine, and the primary route of excretion. A large proportion of Pi flowing to the small intestine was absorbed; however, additional Pi was absorbed from the large intestine (3.15%). Absorption of Pi from the small intestine was regulated, and given the large flux of salivary P recycling, the effective fractional small intestine absorption of available P derived from the diet was 41.6% at requirements. Milk synthesis used 16% of total absorbed P, and less than 1% was excreted in urine. The resulting model could be used to derive P bioavailabilities of commonly used feedstuffs in cattle production.
18. Evapotranspiration parameterizations at a grass site in Florida, USA
USGS Publications Warehouse
Rizou, M.; Sumner, David M.; Nnadi, F.
2007-01-01
In spite of the fact that grasslands account for about 40% of the ice-free global terrestrial land cover, their contribution to the surface exchanges of energy and water in local and regional scale is so far uncertain. In this study, the sensitivity of evapotranspiration (ET) and other energy fluxes to wetness variables, namely the volumetric Soil Water Content (SWC) and Antecedent Precipitation Index (API), over a non-irrigated grass site in Central Florida, USA (28.049 N, 81.400 W) were investigated. Eddy correlation and soil water content measurements were taken by USGS (U.S. Geological Survey) at the grass study site, within 100 m of a SFWMD (South Florida Water Management District) weather station. The soil is composed of fine sands and it is mainly covered by Paspalum notatum (bahia grass). Variable soil wetness conditions with API bounds of about 2 to 160 mm and water table levels of 0.03 to 1.22 m below ground surface, respectively, were observed throughout the year 2004. The Bowen ratio exhibited an average of 1 and values larger than 2 during few dry days. The daytime average ET was classified into two stages, first stage (energy-limited) and second stage (water- limited) based on the water availability. The critical values of API and SWC were found to be about 56 mm and 0.17 respectively, with the second one being approximately 33% of the SWC at saturation. The ET values estimated by the simple Priestley-Taylor (PT) method were compared to the actual values. The PT coefficient varied from a low bound of approximately 0.4 to a peak of 1.21. Simple relationships for the PT empirical factor were employed in terms of SWC and API to improve the accuracy of the second stage observations. The results of the ET parameterizations closely match eddy-covariance flux values on daily and longer time steps.
19. Parameterization of small intestinal water volume using PBPK modeling.
PubMed
Maharaj, Anil; Fotaki, Nikoletta; Edginton, Andrea
2015-01-25
To facilitate accurate predictions of oral drug disposition, mechanistic absorption models require optimal parameterization. Furthermore, parameters should maintain a biological basis to establish confidence in model predictions. This study will serve to calculate an optimal parameter value for small intestinal water volume (SIWV) using a model-based approach. To evaluate physiologic fidelity, derived volume estimates will be compared to experimentally-based SIWV determinations. A compartmental absorption and transit (CAT) model, created in Matlab-Simulink®, was integrated with a whole-body PBPK model, developed in PK-SIM 5.2®, to provide predictions of systemic drug disposition. SIWV within the CAT model was varied between 52.5mL and 420mL. Simulations incorporating specific SIWV values were compared to pharmacokinetic data from compounds exhibiting solubility induced non-proportional changes in absorption using absolute average fold-error. Correspondingly, data pertaining to oral administration of acyclovir and chlorothiazide were utilized to derive estimates of SIWV. At 400mg, a SIWV of 116mL provided the best estimates of acyclovir plasma concentrations. A similar SIWV was found to best depict the urinary excretion pattern of chlorothiazide at a dose of 100mg. In comparison, experimentally-based estimates of SIWV within adults denote a central tendency between 86 and 167mL. The derived SIWV (116mL) represents the optimal parameter value within the context of the developed CAT model. This result demonstrates the biological basis of the widely utilized CAT model as in vivo SIWV determinations correspond with model-based estimates.
20. A parameterization of nuclear track profiles in CR-39 detector
Azooz, A. A.; Al-Nia'emi, S. H.; Al-Jubbori, M. A.
2012-11-01
In this work, the empirical parameterization describing the alpha particles’ track depth in CR-39 detectors is extended to describe longitudinal track profiles against etching time for protons and alpha particles. MATLAB based software is developed for this purpose. The software calculates and plots the depth, diameter, range, residual range, saturation time, and etch rate versus etching time. The software predictions are compared with other experimental data and with results of calculations using the original software, TRACK_TEST, developed for alpha track calculations. The software related to this work is freely downloadable and performs calculations for protons in addition to alpha particles. Program summary Program title: CR39 Catalog identifier: AENA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENA_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Copyright (c) 2011, Aasim Azooz Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met • Redistributions of source code must retain the above copyright, this list of conditions and the following disclaimer. • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution This software is provided by the copyright holders and contributors “as is” and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall the copyright owner or contributors be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption) however caused and
1. A parameterization of nuclear track profiles in CR-39 detector
Azooz, A. A.; Al-Nia'emi, S. H.; Al-Jubbori, M. A.
2012-11-01
In this work, the empirical parameterization describing the alpha particles’ track depth in CR-39 detectors is extended to describe longitudinal track profiles against etching time for protons and alpha particles. MATLAB based software is developed for this purpose. The software calculates and plots the depth, diameter, range, residual range, saturation time, and etch rate versus etching time. The software predictions are compared with other experimental data and with results of calculations using the original software, TRACK_TEST, developed for alpha track calculations. The software related to this work is freely downloadable and performs calculations for protons in addition to alpha particles. Program summary Program title: CR39 Catalog identifier: AENA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENA_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Copyright (c) 2011, Aasim Azooz Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met • Redistributions of source code must retain the above copyright, this list of conditions and the following disclaimer. • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution This software is provided by the copyright holders and contributors “as is” and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall the copyright owner or contributors be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption) however caused and
2. Terahertz scattering by granular composite materials: An effective medium theory
Kaushik, Mayank; Ng, Brian W.-H.; Fischer, Bernd M.; Abbott, Derek
2012-01-01
Terahertz (THz) spectroscopy and imaging have emerged as important tools for identification and classification of various substances, which exhibit absorption characteristics at distinct frequencies in the THz range. The spectral fingerprints can potentially be distorted or obscured by electromagnetic scattering caused by the granular nature of some substances. In this paper, we present THz time domain transmission measurements of granular polyethylene powders in order to investigate an effective medium theory that yields a parameterized model, which can be used to estimate the empirical measurements to good accuracy.
3. Parameterizing Aggregation Rates: Results of cold temperature ice-ash hydrometeor experiments
Courtland, L. M.; Dufek, J.; Mendez, J. S.; McAdams, J.
2014-12-01
Recent advances in the study of tephra aggregation have indicated that (i) far-field effects of tephra sedimentation are not adequately resolved without accounting for aggregation processes that preferentially remove the fine ash fraction of volcanic ejecta from the atmosphere as constituent pieces of larger particles, and (ii) the environmental conditions (e.g. humidity, temperature) prevalent in volcanic plumes may significantly alter the types of aggregation processes at work in different regions of the volcanic plume. The current research extends these findings to explore the role of ice-ash hydrometeor aggregation in various plume environments. Laboratory experiments utilizing an ice nucleation chamber allow us to parameterize tephra aggregation rates under the cold (0 to -50 C) conditions prevalent in the upper regions of volcanic plumes. We consider the interaction of ice-coated tephra of variable thickness grown in a controlled environment. The ice-ash hydrometers interact collisionally and the interaction is recorded by a number of instruments, including high speed video to determine if aggregation occurs. The electric charge on individual particles is examined before and after collision to examine the role of electrostatics in the aggregation process and to examine the charge exchange process. We are able to examine how sticking efficiency is related to both the relative abundance of ice on a particle as well as to the magnitude of the charge carried by the hydrometeor. We here present preliminary results of these experiments, the first to constrain aggregation efficiency of ice-ash hydrometeors, a parameter that will allow tephra dispersion models to use near-real-time meteorological data to better forecast particle residence time in the atmosphere.
4. The Sensitivity of Intraseasonal Variability in the NCAR CCM3 to Changes in Convective Parameterization.
Maloney, Eric D.; Hartmann, Dennis L.
2001-05-01
The National Center for Atmospheric Research (NCAR) Community Climate Model, version 3.6 (CCM3) simulation of tropical intraseasonal variability in zonal winds and precipitation can be improved by implementing the microphysics of cloud with relaxed Arakawa-Schubert (McRAS) convection scheme of Sud and Walker. The default CCM3 convection scheme of Zhang and McFarlane produces intraseasonal variability in both zonal winds and precipitation that is much lower than is observed. The convection scheme of Hack produces high tropical intraseasonal zonal wind variability but no coherent convective variability at intraseasonal timescales and low wavenumbers. The McRAS convection scheme produces realistic variability in tropical intraseasonal zonal winds and improved intraseasonal variability in tropical precipitation, although the variability in precipitation is somewhat less than is observed. Intraseasonal variability in CCM3 with the McRAS scheme is highly sensitive to the parameterization of convective precipitation evaporation in unsaturated environmental air and unsaturated downdrafts. Removing these effects greatly reduces intraseasonal variability in the model. Convective evaporation processes in McRAS affect intraseasonal variability mainly through their time-mean effects and not through their variations. Convective rain evaporation and unsaturated downdrafts improve the modeled specific humidity and temperature climates of the Tropics and increase convection on the equator. Intraseasonal variability in CCM3 with McRAS is not improved by increasing the boundary layer relative humidity threshold for initiation of convection, contrary to the results of Wang and Schlesinger. In fact, intraseasonal variability is reduced for higher thresholds. The largest intraseasonal moisture variations during a model Madden-Julian oscillation life cycle occur above the boundary layer, and humidity variations within the boundary layer are small.
5. Nitrous Oxide Emissions from Biofuel Crops and Parameterization in the EPIC Biogeochemical Model
EPA Science Inventory
This presentation describes year 1 field measurements of N2O fluxes and crop yields which are used to parameterize the EPIC biogeochemical model for the corresponding field site. Initial model simulations are also presented.
6. SENSITIVITY OF THE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION MULTILAYER MODEL TO INSTRUMENT ERROR AND PARAMETERIZATION UNCERTAINTY
EPA Science Inventory
The response of the National Oceanic and Atmospheric Administration multilayer inferential dry deposition velocity model (NOAA-MLM) to error in meteorological inputs and model parameterization is reported. Monte Carlo simulations were performed to assess the uncertainty in NOA...
7. Parameterization of eddy sensible heat transports in a zonally averaged dynamic model of the atmosphere
NASA Technical Reports Server (NTRS)
Genthon, Christophe; Le Treut, Herve; Sadourny, Robert; Jouzel, Jean
1990-01-01
A Charney-Branscome based parameterization has been tested as a way of representing the eddy sensible heat transports missing in a zonally averaged dynamic model (ZADM) of the atmosphere. The ZADM used is a zonally averaged version of a general circulation model (GCM). The parameterized transports in the ZADM are gaged against the corresponding fluxes explicitly simulated in the GCM, using the same zonally averaged boundary conditions in both models. The Charney-Branscome approach neglects stationary eddies and transient barotropic disturbances and relies on a set of simplifying assumptions, including the linear appoximation, to describe growing transient baroclinic eddies. Nevertheless, fairly satisfactory results are obtained when the parameterization is performed interactively with the model. Compared with noninteractive tests, a very efficient restoring feedback effect between the modeled zonal-mean climate and the parameterized meridional eddy transport is identified.
8. A Comparative Study of Nucleation Parameterizations: 2. Three-Dimensional Model Application and Evaluation
EPA Science Inventory
Following the examination and evaluation of 12 nucleation parameterizations presented in part 1, 11 of them representing binary, ternary, kinetic, and cluster‐activated nucleation theories are evaluated in the U.S. Environmental Protection Agency Community Multiscale Air Quality ...
9. Parameterized Cross Sections for Pion Production in Proton-Proton Collisions
NASA Technical Reports Server (NTRS)
Blattnig, Steve R.; Swaminathan, Sudha R.; Kruger, Adam T.; Ngom, Moussa; Norbury, John W.; Tripathi, R. K.
2000-01-01
An accurate knowledge of cross sections for pion production in proton-proton collisions finds wide application in particle physics, astrophysics, cosmic ray physics, and space radiation problems, especially in situations where an incident proton is transported through some medium and knowledge of the output particle spectrum is required when given the input spectrum. In these cases, accurate parameterizations of the cross sections are desired. In this paper much of the experimental data are reviewed and compared with a wide variety of different cross section parameterizations. Therefore, parameterizations of neutral and charged pion cross sections are provided that give a very accurate description of the experimental data. Lorentz invariant differential cross sections, spectral distributions, and total cross section parameterizations are presented.
10. Impact of Multiple Scattering on Infrared Radiative Transfer involving Ice Clouds
Kuo, C. P.; Yang, P.; Huang, X.; Feldman, D.; Flanner, M.
2015-12-01
General circulation models (GCMs) facilitate a major tool to investigate climate on global scale. Since solar and terrestrial radiation control energy budget of global climate, developing an accurate yet computationally efficient radiative transfer model in GCMs is important. However, in most of the GCMs, absorption of ice cloud is the only mechanism considered for the longwave radiative transfer process. Implementation of longwave scattering in GCMs requires parameterizations of ice cloud. This study utilizes spectrally consistent ice particle model in MODIS collection 6 and more than 14,000 particle size distributions from aircraft in-situ observations to parameterize ice cloud longwave optical properties. The new parameterizations are compared with Fu-Liou parameterization implemented in the RRTM_LW (Longwave Rapid Radiative Transfer Model). As accurate and computationally efficient radiative transfer model is important in GCMs, comparison of different radiative transfer methods are performed. Specifically, RRTMG_LW (GCM version of RRTM_LW), one of the most widely utilized radiative transfer schemes in the GCMs, will be modified to include different scattering approximation methods. To evaluate the accuracy, DISORT (Discrete Ordinates Radiative Transfer Program for a Multi-Layered Plane-Parallel Medium) is implemented and compared with other methods in terms of cloud radiative effect and heating rate.
11. Scattering in optical materials
SciTech Connect
Musikant, S.
1983-01-01
Topics discussed include internal scattering and surface scattering, environmental effects, and various applications. Papers are presented on scattering in ZnSe laser windows, the far-infrared reflectance spectra of optical black coatings, the effects of standard optical shop practices on scattering, and the damage susceptibility of ring laser gyro class optics. Attention is also given to the infrared laser stimulated desorption of pyridine from silver surfaces, to electrically conductive black optical paint, to light scattering from an interface bubble, and to the role of diagnostic testing in identifying and resolving dimensional stability problems in electroplated laser mirrors.
12. A scheme for parameterizing ice cloud water content in general circulation models
NASA Technical Reports Server (NTRS)
Heymsfield, Andrew J.; Donner, Leo J.
1989-01-01
A method for specifying ice water content in GCMs is developed, based on theory and in-cloud measurements. A theoretical development of the conceptual precipitation model is given and the aircraft flights used to characterize the ice mass distribution in deep ice clouds is discussed. Ice water content values derived from the theoretical parameterization are compared with the measured values. The results demonstrate that a simple parameterization for atmospheric ice content can account for ice contents observed in several synoptic contexts.
13. Parameterized spectral distributions for meson production in proton-proton collisions
NASA Technical Reports Server (NTRS)
Schneider, John P.; Norbury, John W.; Cucinotta, Francis A.
1995-01-01
Accurate semiempirical parameterizations of the energy-differential cross sections for charged pion and kaon production from proton-proton collisions are presented at energies relevant to cosmic rays. The parameterizations, which depend on both the outgoing meson parallel momentum and the incident proton kinetic energy, are able to be reduced to very simple analytical formulas suitable for cosmic ray transport through spacecraft walls, interstellar space, the atmosphere, and meteorites.
14. Universal statistics of the scattering coefficient of chaotic microwave cavities
SciTech Connect
Hemmady, Sameer; Zheng, Xing; Antonsen, Thomas M. Jr.; Ott, Edward; Anlage, Steven M.
2005-05-01
We consider the statistics of the scattering coefficient S of a chaotic microwave cavity coupled to a single port. We remove the nonuniversal effects of the coupling from the experimental S data using the radiation impedance obtained directly from the experiments. We thus obtain the normalized scattering coefficient whose probability density function (PDF) is predicted to be universal in that it depends only on the loss (quality factor) of the cavity. We compare experimental PDFs of the normalized scattering coefficients with those obtained from random matrix theory (RMT), and find excellent agreement. The results apply to scattering measurements on any wave chaotic system.
15. Molecular graphene under the eye of scattering theory
Hammar, H.; Berggren, P.; Fransson, J.
2013-12-01
The recent experimental observations of designer Dirac fermions and topological phases in molecular graphene are addressed theoretically. Using scattering theory, we calculate the electronic structure of finite lattices of scattering centers dual to the honeycomb lattice. In good agreement with experimental observations, we obtain a V-shaped electron density of states around the Fermi energy. By varying the lattice parameter we simulate electron and hole doping of the structure, and by adding and removing scattering centers we simulate, respectively, vacancy and impurity defects. Specifically, for the vacancy defect we verify the emergence of a sharp resonance near the Fermi energy for increasing strength of the scattering potential.
16. Universal statistics of the scattering coefficient of chaotic microwave cavities.
PubMed
Hemmady, Sameer; Zheng, Xing; Antonsen, Thomas M; Ott, Edward; Anlage, Steven M
2005-05-01
We consider the statistics of the scattering coefficient S of a chaotic microwave cavity coupled to a single port. We remove the nonuniversal effects of the coupling from the experimental S data using the radiation impedance obtained directly from the experiments. We thus obtain the normalized scattering coefficient whose probability density function (PDF) is predicted to be universal in that it depends only on the loss (quality factor) of the cavity. We compare experimental PDFs of the normalized scattering coefficients with those obtained from random matrix theory (RMT), and find excellent agreement. The results apply to scattering measurements on any wave chaotic system.
17. An airfoil parameterization method for the representation and optimization of wind turbine special airfoil
Liu, Yixiong; Yang, Ce; Song, Xiancheng
2015-04-01
A new airfoil shape parameterization method is developed, which extended the Bezier curve to the generalized form with adjustable shape parameters. The local control parameters at airfoil leading and trailing edge regions are enhanced, where have significant effect on the aerodynamic performance of wind turbine. The results show this improved parameterization method has advantages in the fitting characteristics of geometry shape and aerodynamic performance comparing with other three common airfoil parameterization methods. The new parameterization method is then applied to airfoil shape optimization for wind turbine using Genetic Algorithm (GA), and the wind turbine special airfoil, DU93-W-210, is optimized to achieve the favorable Cl/Cd at specified flow conditions. The aerodynamic characteristic of the optimum airfoil is obtained by solving the RANS equations in computational fluid dynamics (CFD) method, and the optimization convergence curves show that the new parameterization method has good convergence rate in less number of generations comparing with other methods. It is concluded that the new method not only has well controllability and completeness in airfoil shape representation and provides more flexibility in expressing the airfoil geometry shape, but also is capable to find efficient and optimal wind turbine airfoil. Additionally, it is shown that a suitable parameterization method is helpful for improving the convergence rate of the optimization algorithm.
18. Implementation of stochastic parameterization of surface variables in ensemble forecasts
Weidle, F.; Wang, Y.; Wittmann, C.; Tang, J.; Xia, F.
2012-04-01
To represent uncertainties in the numerical weather prediction, various ensemble forecasting systems have been recently developed by different weather services around the world. Most ensemble systems account for uncertainties in the initial conditions and for limited area ensemble systems also errors in the lateral boundary conditions are considered by using one or more global ensemble systems as coupling model. To account for uncertainties in the model a stochastic physic scheme is one possibility which is in use in some ensemble systems. In forecast models surface processes are typically treated by parameterizations to represent physical processes at the interface between surface and atmosphere. Especially for the forecast quality of near surface fields these processes can play a crucial role but also for the formation of precipitation in the atmosphere. However, uncertainties in the forecast due to errors in the representation of surface processes, which can feed back to atmospheric processes are not yet considered in any operational ensemble system. The aim of the work is to investigate whether the representation of uncertainties in the surface scheme of an ensemble system can improve the probabilistic forecast. Therefore a stochastic physics scheme for surface processes, similar to the stochastic physics scheme that has been used for several years in the ECMWF-EPS, is implemented in ALADIN-LAEF, the operational limited area ensemble model of the Austrian Weather service. The stochastic physic method is used to randomly perturb tendencies of surface variables, for example soil moisture and surface temperature in the surface scheme, during the forecast. In the presentation the implementation in ALADIN-LAEF is introduced and simulations of high impact weather situations as well as a verification over 3 months against forecasts without perturbing surface fields will be presented. To verify the importance of the representation of uncertainties due to surface
19. Mantle Dynamics Studied with Parameterized Prescription From Mineral Physics Database
Tosi, N.; Yuen, D.; Wentzcovich, R.; deKoker, N.
2012-04-01
The incorporation of important thermodynamic and transport properties into mantle convection models has taken a long time for the community to appreciate, even though it was first spurred by the high-pressure experimental work at Mainz a quarter of a century ago and the experimental work at Bayreuth and St. Louis. The two quantities whose effects have yet to be widely appreciated are thermal expansivity α and thermal conductivity k, which are shown to impact mantle dynamics and thermal history in more ways than geoscientists have previously imagined. We have constructed simple parameterization schemes, which are cast analytically for describing α and k over a wide range of temperatures and pressures corresponding to the Earth's mantle. This approach employs the thermodynamics data set drawn from the VLAB at the University of Minnesota based on first-principles density functional theory [1] and also recent laboratory data from the Bayreuth group [2]. Using analytical formulae to determine α and k increases the computational speed of the convection code with respect to employing pre-calculated look-up tables and allows us to sweep out a wide parameter space. Our results, which also incorporate temperature and pressure dependent viscosity show the following prominent features: 1) The temperature-dependence of α is important in the upper mantle. It enhances strongly the rising hot plumes and inhibits the cold downwellings, thus making subduction more difficult for young slabs. 2) The pressure dependence of α is dominant in the lower mantle. It focuses upwellings and speeds them up during their upward rise. 3) The temperature-dependence of the thermal conductivity helps to homogenize the lateral thermal anomalies in cold downwellings and helps to maintain the heat in the upwellings, thus, in concert with alpha, helps to encourage fast hot plumes. 4) The lattice thermal conductivity of post-perovskite plays an important role in heat-transfer in the lower mantle and
20. Rainfall droplet size distributions (DSD) parameterization: physics and sensibility
2014-12-01
The CHUVA project (Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)) is a Brazillian experiment that aims to understand the several cloud processes that occur in different precipitating regimes. At present, the CHUVA project has conducted 6 field campaigns, the last one being in Manaus jointly with GoAmazon, IARA and ACRIDICON. The main focus of the present study is to bring into perspective the different characteristics of precipitation that reaches the surface in Brazil over several locations. To do so, disdrometer data is analyzed in detail, employing a Gamma fit for each DSD measurement which provides the respective parameters to be studied. Those are disposed in a 3D space, each axis corresponding to one parameter, and the patterns are analyzed. A correlation between the Gamma parameters is defined as a parametric surface that fits the observations with errors smaller than 10% and R2 greater than 0.95. In this way, one parameter can be estimated with respect to the other two, reducing the degrees of freedom of the problem from 3 to 2. As the 3 parameters are defined over this surface, it's possible to obtain a surface representing integral DSD properties such as rainfall intensity (RI). Sensibilities tests are conducted on this estimation and also on other DSD characteristics such as total droplet concentrations and mean mass-weighted diameter. It's shown that the DSD integral properties are generally very sensitive to the Gamma parameters. Nonetheless, the sensibility varies over the surface, being higher in a region where the parameters are not balanced (i.e. a relatively high value in one parameter and low values on the other two). It's suggested that any study proposing parameterization/estimation of DSD properties should be aware of this region of high sensitivity. To further the collaboration with GoAmazon and ACRIDICON, the disdrometer results
1. Selection and parameterization of cortical neurons for neuroprosthetic control
Wahnoun, Remy; He, Jiping; Helms Tillery, Stephen I.
2006-06-01
When designing neuroprosthetic interfaces for motor function, it is crucial to have a system that can extract reliable information from available neural signals and produce an output suitable for real life applications. Systems designed to date have relied on establishing a relationship between neural discharge patterns in motor cortical areas and limb movement, an approach not suitable for patients who require such implants but who are unable to provide proper motor behavior to initially tune the system. We describe here a method that allows rapid tuning of a population vector-based system for neural control without arm movements. We trained highly motivated primates to observe a 3D center-out task as the computer played it very slowly. Based on only 10-12 s of neuronal activity observed in M1 and PMd, we generated an initial mapping between neural activity and device motion that the animal could successfully use for neuroprosthetic control. Subsequent tunings of the parameters led to improvements in control, but the initial selection of neurons and estimated preferred direction for those cells remained stable throughout the remainder of the day. Using this system, we have observed that the contribution of individual neurons to the overall control of the system is very heterogeneous. We thus derived a novel measure of unit quality and an indexing scheme that allowed us to rate each neuron's contribution to the overall control. In offline tests, we found that fewer than half of the units made positive contributions to the performance. We tested this experimentally by having the animals control the neuroprosthetic system using only the 20 best neurons. We found that performance in this case was better than when the entire set of available neurons was used. Based on these results, we believe that, with careful task design, it is feasible to parameterize control systems without any overt behaviors and that subsequent control system design will be enhanced with
2. A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli
Berg, L. K.; Shrivastava, M.; Easter, R. C.; Fast, J. D.; Chapman, E. G.; Liu, Y.; Ferrare, R. A.
2015-02-01
A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud-aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it is anticipated
3. Comparing momentum and mass (aerosol source function) fluxes for the North Atlantic and the European Arctic using different parameterizations
Wróbel, Iwona; Piskozub, Jacek
2016-04-01
Wind speed has a disproportionate role in the forming of the climate as well it is important part in calculate of the air-sea interaction thanks which we can study climate change. It influences on mass, momentum and energy fluxes and the standard way of parametrizing those fluxes is use this variable. However, the very functions used to calculate fluxes from winds have evolved over time and still have large differences (especially in the case of aerosol sources function). As we have shown last year at the EGU conference (PICO presentation EGU2015-11206-1) and in recent public article (OSD 12,C1262-C1264,2015) there is a lot of uncertainties in the case of air-sea CO2 fluxes. In this study we calculated regional and global mass and momentum fluxes based on several wind speed climatologies. To do this we use wind speed from satellite data in FluxEngine software created within OceanFlux GHG Evolution project. Our main area of interest is European Arctic because of the interesting air-sea interaction physics (six-monthly cycle, strong wind and ice cover) but because of better data coverage we have chosen the North Atlantic as a study region to make it possible to compare the calculated fluxes to measured ones. An additional reason was the importance of the area for the North Hemisphere climate, and especially for Europe. The study is related to an ESA funded OceanFlux GHG Evolution project and is meant to be part of a PhD thesis (of I.W) funded by Centre of Polar Studies "POLAR-KNOW" (a project of the Polish Ministry of Science). We have used a modified version FluxEngine, a tool created within an earlier ESA funded project (OceanFlux Greenhouse Gases) for calculating trace gas fluxes to derive two purely wind driven (at least in the simplified form used in their parameterizations) fluxes. The modifications included removing gas transfer velocity formula from the toolset and replacing it with the respective formulas for momentum transfer and mass (aerosol production
4. Algorithmic scatter correction in dual-energy digital mammography
SciTech Connect
Chen, Xi; Mou, Xuanqin; Nishikawa, Robert M.; Lau, Beverly A.; Chan, Suk-tak; Zhang, Lei
2013-11-15
Purpose: Small calcifications are often the earliest and the main indicator of breast cancer. Dual-energy digital mammography (DEDM) has been considered as a promising technique to improve the detectability of calcifications since it can be used to suppress the contrast between adipose and glandular tissues of the breast. X-ray scatter leads to erroneous calculations of the DEDM image. Although the pinhole-array interpolation method can estimate scattered radiations, it requires extra exposures to measure the scatter and apply the correction. The purpose of this work is to design an algorithmic method for scatter correction in DEDM without extra exposures.Methods: In this paper, a scatter correction method for DEDM was developed based on the knowledge that scattered radiation has small spatial variation and that the majority of pixels in a mammogram are noncalcification pixels. The scatter fraction was estimated in the DEDM calculation and the measured scatter fraction was used to remove scatter from the image. The scatter correction method was implemented on a commercial full-field digital mammography system with breast tissue equivalent phantom and calcification phantom. The authors also implemented the pinhole-array interpolation scatter correction method on the system. Phantom results for both methods are presented and discussed. The authors compared the background DE calcification signals and the contrast-to-noise ratio (CNR) of calcifications in the three DE calcification images: image without scatter correction, image with scatter correction using pinhole-array interpolation method, and image with scatter correction using the authors' algorithmic method.Results: The authors' results show that the resultant background DE calcification signal can be reduced. The root-mean-square of background DE calcification signal of 1962 μm with scatter-uncorrected data was reduced to 194 μm after scatter correction using the authors' algorithmic method. The range of
5. Use of satellite data to improve parameterization of spatial and temporal variations of gaseous dry deposition in regional-scale models
SciTech Connect
Gao, Weigang; Wesely, M.L.
1994-01-01
The removal of gaseous substances from the atmosphere by dry deposition represents an important sink in the atmospheric budget for many trace gases. The surface removal rate, therefore, needs be described quantitatively in modeling atmospheric transport and chemistry with regional- and global-scale models. Because the uptake capability of a terrestrial surface is strongly influenced by the type and condition of its vegetation, the seasonal and spatial changes in vegetation should be described in considerable detail in large-scale models. The objective of the present study is to develop a model that links remote sensing data from satellites with the RADM dry deposition module to provide a parameterization of dry deposition over large scales with improved temporal and spatial coverage. This paper briefly discusses the modeling methods and initial results obtained by applying the improved dry deposition module to a tallgrass prairie, for which measurements of O{sub 3} dry deposition and simultaneously obtained satellite remote sensing data are available.
6. Assessment of aerosol-cloud interactions during southern African biomass burning activity, employing cloud parameterizations
Wiston, Modise; McFiggans, Gordon; Schultz, David
2015-04-01
In this study, we perform a simulation of the spatial distributions of particle and gas concentrations from a significantly large source of pollution event during a dry season in southern Africa and their interactions with cloud processes. Specific focus is on the extent to which cloud-aerosol interactions are affected by various inputs (i.e. emissions) and parameterizations and feedback mechanisms in a coupled mesoscale chemistry-meteorology model -herein Weather Research and Forecasting model with chemistry (WRF-Chem). The southern African dry season (May-Sep) is characterised by biomass burning (BB) type of pollution. During this period, BB particles are frequently observed over the subcontinent, at the same time a persistent deck of stratocumulus covers the south West African coast, favouring long-range transport over the Atlantic Ocean of aerosols above clouds. While anthropogenic pollutants tend to spread more over the entire domain, biomass pollutants are concentrated around the burning areas, especially the savannah and tropical rainforest of the Congo Basin. BB is linked to agricultural practice at latitudes south of 10° N. During an intense burning event, there is a clear signal of strong interactions of aerosols and cloud microphysics. These species interfere with the radiative budget, and directly affect the amount of solar radiation reflected and scattered back to space and partly absorbed by the atmosphere. Aerosols also affect cloud microphysics by acting as cloud condensation nuclei (CCN), modifying precipitation pattern and the cloud albedo. Key area is to understand the role of pollution on convective cloud processes and its impacts on cloud dynamics. The hypothesis is that an environment of potentially high pollution enables the probability of interactions between co-located aerosols and cloud layers. To investigate this hypothesis, we outline an approach to integrate three elements: i) focusing on regime(s) where there are strong indications of
7. A Fast Radiative Transfer Parameterization Under Cloudy Condition in Solar Spectral Region
Yang, Q.; Liu, X.; Yang, P.; Wang, C.
2014-12-01
8. Study on linear and nonlinear bottom friction parameterizations for regional tidal models using data assimilation
Zhang, Jicai; Lu, Xianqing; Wang, Ping; Wang, Ya Ping
2011-04-01
Data assimilation technique (adjoint method) is applied to study the similarities and the differences between the Ekman (linear) and the Quadratic (nonlinear) bottom friction parameterizations for a two-dimensional tidal model. Two methods are used to treat the bottom friction coefficient (BFC). The first method assumes that the BFC is a constant in the entire computation domain, while the second applies the spatially varying BFCs. The adjoint expressions for the linear and the nonlinear parameterizations and the optimization formulae for the two BFC methods are derived based on the typical Largrangian multiplier method. By assimilating the model-generated 'observations', identical twin experiments are performed to test and validate the inversion ability of the presented methodology. Four experiments, which employ the linear parameterization, the nonlinear parameterizations, the constant BFC and the spatially varying BFC, are carried out to simulate the M 2 tide in the Bohai Sea and the Yellow Sea by assimilating the TOPEX/Poseidon altimetry and tidal gauge data. After the assimilation, the misfit between model-produced and observed data is significantly decreased in the four experiments. The simulation results indicate that the nonlinear Quadratic parameterization is more accurate than the linear Ekman parameterization if the traditional constant BFC is used. However, when the spatially varying BFCs are used, the differences between the Ekman and the Quadratic approaches diminished, the reason of which is analyzed from the viewpoint of dissipation rate caused by bottom friction. Generally speaking, linear bottom friction parameterizations are often used in global tidal models. This study indicates that they are also applicable in regional ocean tidal models with the combination of spatially varying parameters and the adjoint method.
9. Spatially heterogeneous diapycnal mixing in the abyssal ocean: A comparison of two parameterizations to observations
Decloedt, Thomas; Luther, Douglas S.
2012-11-01
The spatial distributions of the diapycnal diffusivity predicted by two abyssal mixing schemes are compared to each other and to observational estimates based on microstructure surveys and large-scale hydrographic inversions. The parameterizations considered are the tidal mixing scheme by Jayne, St. Laurent and co-authors (JSL01) and the Roughness Diffusivity Model (RDM) by Decloedt and Luther. Comparison to microstructure surveys shows that both parameterizations are conservative in estimating the vertical extent to which bottom-intensified mixing penetrates into the stratified water column. In particular, the JSL01 exponential vertical structure function with fixed scale height decays to background values much nearer topography than observed. JSL01 and RDM yield dramatically different horizontal spatial distributions of diapycnal diffusivity, which would lead to quite different circulations in OGCMs, yet they produce similar basin-averaged diffusivity profiles. Both parameterizations are shown to yield smaller basin-mean diffusivity profiles than hydrographic inverse estimates for the major ocean basins, by factors ranging from 3 up to over an order of magnitude. The canonical 10-4 m2 s-1abyssal diffusivity is reached by the parameterizations only at depths below 3 km. Power consumption by diapycnal mixing below 1 km of depth, between roughly 32°S and 48°N, for the RDM and JSL01 parameterizations is 0.40 TW & 0.28 TW, respectively. The results presented here suggest that present-day mixing parameterizations significantly underestimate abyssal mixing. In conjunction with other recently published studies, a plausible interpretation is that parameterizing the dissipation of bottom-generated internal waves is not sufficient to approximate the global spatial distribution of diapycnal mixing in the abyssal ocean.
10. Development of embedded modulated scatterer technique: Single- and dual-loaded scatterers
Donnell, Kristen Marie
Health monitoring of infrastructure is an important ongoing issue. Therefore, it is important that a cost-effective and practical method for evaluating complex composite structures be developed. A promising microwave-based embedded sensor technology is developed based on the Modulated Scatterer Technique (MST). MST is based on illuminating a probe, commonly a dipole antenna loaded with a PIN diode (also referred to as a single-loaded scatterer, or SLS), with an electromagnetic wave. This impinging wave induces a current along the scatterer length, which causes a scattered field to be reradiated. Modulating the PIN diode also modulates the signal scattered by the probe, resulting in two different states of the probe. By measuring this scattered field, information about the material in the vicinity of the probe may be determined. Using the ratio of both states of the probe removes the dependency of MST on several measurement parameters. In order to separate the scattered signal from reflections from other targets present in the total detected signal, a swept-frequency measurement process and subsequent Fourier Transform (time-gate method) was incorporated into MST. Additionally, a full electromagnetic study of the SLS, as applied to MST, was also conducted. The increased measurement complexity and data processing resulting from the time-gate method prompted the development of a novel dual-loaded scatterer (DLS) probe design, with four possible modulation states. By taking a differential ratio, the reflections from other targets can be effectively removed, while preserving the measurement parameter independence of the SLS ratio. A full electromagnetic derivation and analysis of the capabilities of the DLS as applied to MST is included in this investigation, as well as representative measurements using the DLS probe.
11. Cloud Simulations in Response to Turbulence Parameterizations in the GISS Model E GCM
NASA Technical Reports Server (NTRS)
Yao, Mao-Sung; Cheng, Ye
2013-01-01
The response of cloud simulations to turbulence parameterizations is studied systematically using the GISS general circulation model (GCM) E2 employed in the Intergovernmental Panel on Climate Change's (IPCC) Fifth Assessment Report (AR5).Without the turbulence parameterization, the relative humidity (RH) and the low cloud cover peak unrealistically close to the surface; with the dry convection or with only the local turbulence parameterization, these two quantities improve their vertical structures, but the vertical transport of water vapor is still weak in the planetary boundary layers (PBLs); with both local and nonlocal turbulence parameterizations, the RH and low cloud cover have better vertical structures in all latitudes due to more significant vertical transport of water vapor in the PBL. The study also compares the cloud and radiation climatologies obtained from an experiment using a newer version of turbulence parameterization being developed at GISS with those obtained from the AR5 version. This newer scheme differs from the AR5 version in computing nonlocal transports, turbulent length scale, and PBL height and shows significant improvements in cloud and radiation simulations, especially over the subtropical eastern oceans and the southern oceans. The diagnosed PBL heights appear to correlate well with the low cloud distribution over oceans. This suggests that a cloud-producing scheme needs to be constructed in a framework that also takes the turbulence into consideration.
12. On parameterization of the inverse problem for estimating aquifer properties using tracer data
SciTech Connect
Kowalsky, M. B.; Finsterle, Stefan A.; Williams, Kenneth H.; Murray, Christopher J.; Commer, Michael; Newcomer, Darrell R.; Englert, Andreas L.; Steefel, Carl I.; Hubbard, Susan
2012-06-11
We consider a field-scale tracer experiment conducted in 2007 in a shallow uranium-contaminated aquifer at Rifle, Colorado. In developing a reliable approach for inferring hydrological properties at the site through inverse modeling of the tracer data, decisions made on how to parameterize heterogeneity (i.e., how to represent a heterogeneous distribution using a limited number of parameters that are amenable to estimation) are of paramount importance. We present an approach for hydrological inversion of the tracer data and explore, using a 2D synthetic example at first, how parameterization affects the solution, and how additional characterization data could be incorporated to reduce uncertainty. Specifically, we examine sensitivity of the results to the configuration of pilot points used in a geostatistical parameterization, and to the sampling frequency and measurement error of the concentration data. A reliable solution of the inverse problem is found when the pilot point configuration is carefully implemented. In addition, we examine the use of a zonation parameterization, in which the geometry of the geological facies is known (e.g., from geophysical data or core data), to reduce the non-uniqueness of the solution and the number of unknown parameters to be estimated. When zonation information is only available for a limited region, special treatment in the remainder of the model is necessary, such as using a geostatistical parameterization. Finally, inversion of the actual field data is performed using 2D and 3D models, and results are compared with slug test data.
13. Albedo of coastal landfast sea ice in Prydz Bay, Antarctica: Observations and parameterization
Yang, Qinghua; Liu, Jiping; Leppäranta, Matti; Sun, Qizhen; Li, Rongbin; Zhang, Lin; Jung, Thomas; Lei, Ruibo; Zhang, Zhanhai; Li, Ming; Zhao, Jiechen; Cheng, Jingjing
2016-05-01
The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica (off Zhongshan Station) during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was a combination of a gradual seasonal transition from spring to summer and abrupt changes resulting from synoptic events, including snowfall, blowing snow, and overcast skies. The measured albedo ranged from 0.94 over thick fresh snow to 0.36 over melting sea ice. It was found that snow thickness was the most important factor influencing the albedo variation, while synoptic events and overcast skies could increase the albedo by about 0.18 and 0.06, respectively. The in-situ measured albedo and related physical parameters (e.g., snow thickness, ice thickness, surface temperature, and air temperature) were then used to evaluate four different snow/ice albedo parameterizations used in a variety of climate models. The parameterized albedos showed substantial discrepancies compared to the observed albedo, particularly during the summer melt period, even though more complex parameterizations yielded more realistic variations than simple ones. A modified parameterization was developed, which further considered synoptic events, cloud cover, and the local landfast sea-ice surface characteristics. The resulting parameterized albedo showed very good agreement with the observed albedo.
14. Parameterized signal calibration for NMR cryoporometry experiment without external standard
Stoch, Grzegorz; Krzyżak, Artur T.
2016-08-01
In cryoporometric experiments non-linear effects associated with the sample and the probehead bring unwanted contributions to the total signal along with the change of temperature. The elimination of these influences often occurs with the help of an intermediate measurement of a separate liquid sample. In this paper we suggest an alternative approach under certain assumptions, solely based on data from the target experiment. In order to obtain calibration parameters the method uses all of these raw data points. Its reliability is therefore enhanced as compared to other methods based on lesser number of data points. Presented approach is automatically valid for desired temperature range. The need for intermediate measurement is removed and parameters for such a calibration are naturally adapted to the individual sample-probehead combination.
15. Limitations in scatter propagation
Lampert, E. W.
1982-04-01
A short description of the main scatter propagation mechanisms is presented; troposcatter, meteor burst communication and chaff scatter. For these propagation modes, in particular for troposcatter, the important specific limitations discussed are: link budget and resulting hardware consequences, diversity, mobility, information transfer and intermodulation and intersymbol interference, frequency range and future extension in frequency range for troposcatter, and compatibility with other services (EMC).
16. Deriving effective atomic numbers from DECT based on a parameterization of the ratio of high and low linear attenuation coefficients.
PubMed
Landry, Guillaume; Seco, Joao; Gaudreault, Mathieu; Verhaegen, Frank
2013-10-01
tissue substitutes were well fitted by the TSM with R(2) = 0.9930. Residuals on Zeff for the phantoms were similar between the TSM and spectral methods for Zeff < 8 while they were improved by the TSM for higher Zeff. The RTM fitted the reference tissue dataset well with R(2) = 0.9999. Comparing the Zeff extracted from TSM and the more complex RTM to the known values from the reference tissue dataset yielded errors of up to 0.3 and 0.15 units of Zeff respectively. The parameterization approach yielded standard deviations which were up to 0.3 units of Zeff higher than those observed with the spectral method for Zeff around 7.5. Procedures for the DECT estimation of Zeff removing the need for estimates of the CT scanner spectra have been presented. Both the TSM and the more complex RTM performed better than the spectral method. The RTM yielded the best results for the reference human tissue dataset reducing errors from up to 0.3 to 0.15 units of Zeff compared to the simpler TSM. Both TSM and RTM are simpler to implement than the spectral method which requires estimates of the CT scanner spectra.
17. Neutron scattering and models : molybdenum.
SciTech Connect
Smith, A.B.
1999-05-26
A comprehensive interpretation of the fast-neutron interaction with elemental and isotopic molybdenum at energies of {le} 30 MeV is given. New experimental elemental-scattering information over the incident energy range 4.5 {r_arrow} 10 MeV is presented. Spherical, vibrational and dispersive models are deduced and discussed, including isospin, energy-dependent and mass effects. The vibrational models are consistent with the ''Lane potential''. The importance of dispersion effects is noted. Dichotomies that exist in the literature are removed. The models are vehicles for fundamental physical investigations and for the provision of data for applied purposes. A ''regional'' molybdenum model is proposed. Finally, recommendations for future work are made.
18. Aureolegraph internal scattering correction.
PubMed
DeVore, John; Villanucci, Dennis; LePage, Andrew
2012-11-20
Two methods of determining instrumental scattering for correcting aureolegraph measurements of particulate solar scattering are presented. One involves subtracting measurements made with and without an external occluding ball and the other is a modification of the Langley Plot method and involves extrapolating aureolegraph measurements collected through a large range of solar zenith angles. Examples of internal scattering correction determinations using the latter method show similar power-law dependencies on scattering, but vary by roughly a factor of 8 and suggest that changing aerosol conditions during the determinations render this method problematic. Examples of corrections of scattering profiles using the former method are presented for a range of atmospheric particulate layers from aerosols to cumulus and cirrus clouds.
19. Aureolegraph internal scattering correction.
PubMed
DeVore, John; Villanucci, Dennis; LePage, Andrew
2012-11-20
Two methods of determining instrumental scattering for correcting aureolegraph measurements of particulate solar scattering are presented. One involves subtracting measurements made with and without an external occluding ball and the other is a modification of the Langley Plot method and involves extrapolating aureolegraph measurements collected through a large range of solar zenith angles. Examples of internal scattering correction determinations using the latter method show similar power-law dependencies on scattering, but vary by roughly a factor of 8 and suggest that changing aerosol conditions during the determinations render this method problematic. Examples of corrections of scattering profiles using the former method are presented for a range of atmospheric particulate layers from aerosols to cumulus and cirrus clouds. PMID:23207299
20. Physically based parameterizations of the short-wave radiative characteristics of weakly absorbing optically thick media: application to liquid-water clouds.
PubMed
Kokhanovsky, A A; Nakajima, T; Zege, E P
1998-07-20
We propose the physically based parameterization of the radiative characteristics of liquid-water clouds as functions of the wavelength, effective radius, and refractive index of particles, liquid-water path, ground albedo, and solar and observation angles. The formulas obtained are based on the approximate analytical solutions of the radiative transfer equation for optically thick, weakly absorbing layers and the geometrical optics approximation for local optical characteristics of cloud media. The accuracy of the approximate formulas was studied with an exact radiative transfer code. The relative error of the approximate formula for the reflection function at nadir observations was less then 15% for an optical thickness larger than 10 and a single-scattering albedo larger than 0.95.
1. Organic Aerosol Volatility Parameterizations and Their Impact on Atmospheric Composition and Climate
NASA Technical Reports Server (NTRS)
Tsigaridis, Kostas; Bauer, Susanne E.
2015-01-01
Despite their importance and ubiquity in the atmosphere, organic aerosols are still very poorly parameterized in global models. This can be explained by two reasons: first, a very large number of unconstrained parameters are involved in accurate parameterizations, and second, a detailed description of semi-volatile organics is computationally very expensive. Even organic aerosol properties that are known to play a major role in the atmosphere, namely volatility and aging, are poorly resolved in global models, if at all. Studies with different models and different parameterizations have not been conclusive on whether the additional complexity improves model simulations, but the added diversity of the different host models used adds an unnecessary degree of variability in the evaluation of results that obscures solid conclusions. Aerosol microphysics do not significantly alter the mean OA vertical profile or comparison with surface measurements. This might not be the case for semi-volatile OA with microphysics.
2. Organic Aerosol Volatility Parameterizations and Their Impact on Atmospheric Composition and Climate
NASA Technical Reports Server (NTRS)
Tsigaridis, Konsta; Bauer, Susanne E.
2015-01-01
Despite their importance and ubiquity in the atmosphere, organic aerosols are still very poorly parameterized in global models. This can be explained by two reasons: first, a very large number of unconstrained parameters are involved in accurate parameterizations, and second, a detailed description of semi-volatile organics is computationally very expensive. Even organic aerosol properties that are known to play a major role in the atmosphere, namely volatility and aging, are poorly resolved in global models, if at all. Studies with different models and different parameterizations have not been conclusive on whether the additional complexity improves model simulations, but the added diversity of the different host models used adds an unnecessary degree of variability in the evaluation of results that obscures solid conclusions.
3. A wave roughness Reynolds number parameterization of the sea spray source flux
Norris, Sarah J.; Brooks, Ian M.; Salisbury, Dominic J.
2013-08-01
of the sea spray aerosol source flux are derived as functions of wave roughness Reynolds numbers, RHa and RHw, for particles with radii between 0.176 and 6.61 µm at 80% relative humidity. These source functions account for up to twice the variance in the observations than does wind speed alone. This is the first such direct demonstration of the impact of wave state on the variability of sea spray aerosol production. Global European Centre for Medium-Range Weather Forecasts operational mode fields are used to drive the parameterizations. The source flux from the RH parameterizations varies from approximately 0.1 to 3 (RHa) and 5 (RHw) times that from a wind speed parameterization, derived from the same measurements, where the wave state is substantially underdeveloped or overdeveloped, respectively, compared to the equilibrium wave state at the local wind speed.
4. A second-order Budkyo-type parameterization of landsurface hydrology
NASA Technical Reports Server (NTRS)
Andreou, S. A.; Eagleson, P. S.
1982-01-01
A simple, second order parameterization of the water fluxes at a land surface for use as the appropriate boundary condition in general circulation models of the global atmosphere was developed. The derived parameterization incorporates the high nonlinearities in the relationship between the near surface soil moisture and the evaporation, runoff and percolation fluxes. Based on the one dimensional statistical dynamic derivation of the annual water balance, it makes the transition to short term prediction of the moisture fluxes, through a Taylor expansion around the average annual soil moisture. A comparison of the suggested parameterization is made with other existing techniques and available measurements. A thermodynamic coupling is applied in order to obtain estimations of the surface ground temperature.
5. Whys and Hows of the Parameterized Interval Analyses: A Guide for the Perplexed
Elishakoff, I.
2013-10-01
Novel elements of the parameterized interval analysis developed in [1, 2] are emphasized in this response, to Professor E.D. Popova, or possibly to others who may be perplexed by the parameterized interval analysis. It is also shown that the overwhelming majority of comments by Popova [3] are based on a misreading of our paper [1]. Partial responsibility for this misreading can be attributed to the fact that explanations provided in [1] were laconic. These could have been more extensive in view of the novelty of our approach [1, 2]. It is our duty, therefore, to reiterate, in this response, the whys and hows of parameterization of intervals, introduced in [1] to incorporate the possibly available information on dependencies between various intervals describing the problem at hand. This possibility appears to have been discarded by the standard interval analysis, which may, as a result, lead to overdesign, leading to the possible divorce of engineers from the otherwise beautiful interval analysis.
6. A review of recent research on improvement of physical parameterizations in the GLA GCM
NASA Technical Reports Server (NTRS)
Sud, Y. C.; Walker, G. K.
1990-01-01
A systematic assessment of the effect of a series of improvements in physical parameterizations of the Goddard Laboratory for Atmospheres (GLA) general circulation model (GCM) are summarized. The implementation of the Simple Biosphere Model (SiB) in the GCM is followed by a comparison of SiB GCM simulations with that of the earlier slab soil hydrology GCM (SSH-GCM) simulations. In the Sahelian context, the biogeophysical component of desertification was analyzed for SiB-GCM simulations. Cumulus parameterization is found to be the primary determinant of the organization of the simulated tropical rainfall of the GLA GCM using Arakawa-Schubert cumulus parameterization. A comparison of model simulations with station data revealed excessive shortwave radiation accompanied by excessive drying and heating to the land. The perpetual July simulations with and without interactive soil moisture shows that 30 to 40 day oscillations may be a natural mode of the simulated earth atmosphere system.
7. Exponential parameterization of neutrino mixing matrix with account of CP-violation data
Zhukovsky, Konstantin; Melazzini, Francisco
2016-08-01
The exponential parameterization of the Pontecorvo-Maki-Nakagawa-Sakata mixing matrix for neutrinos is discussed. The exponential form allows easy factorization and separate analysis of the CP-violating and Majorana terms. Based upon the recent experimental data on the neutrino mixing, the values for the exponential parameterization matrix for neutrinos are determined. The matrix entries for the pure rotational part in charge of the mixing without CP violation are derived. The complementarity hypothesis for quarks and neutrinos is demonstrated. A comparison of the results based on most recent and on old data is presented. The CP-violating parameter value is estimated, based on the so far imprecise experimental indications, regarding CP violation for neutrinos. The unitarity of the exponential parameterization and the CP-violating term transform is confirmed. The transform of the neutrino mass state vector by the exponential matrix with account of CP violation is shown.
8. Impact of a scale-aware cumulus parameterization in an operational NWP system modeling system
Chen, Baode; Yang, Yuhua; Wang, Xiaofeng
2014-05-01
To better understand the behavior of convective schemes across the grey zone, we carried out one-month (July of 2013) realtime-like experiment with an operational NWP system modeling system which includes the ADAS data assimilation scheme and WRF forecast model. The Grell-Freitas cumulus parameterization scheme, which is a scale-aware convective parameterization scheme and has been developed to better handle the transition in behavior of the sub-grid scale convective processes through the grey zone, was used in different resolution (15km, 9km and 3km) model set-up. Subjective and quantitative evaluations of the forecasts were conducted and the skills of the different experimental forecasts relatively to existing forecasting guidance were compared. A summary of the preliminary findings about the proportion of resolved vs unresolved physical processes in the gray zone will be presented along with a discussion of the potential operational impacts of the cumulus parameterization.
9. Developing a unified parameterization of diabatic heating for regional climate modeling simulations
Beltran-Przekurat, A. B.; Pielke, R. A., Sr.; Leoncini, G.; Gabriel, P.
2009-12-01
Conventionally, turbulence fluxes, short- and longwave radiative fluxes, and convective and stratiform cloud precipitation atmospheric processes are separately parameterized as a one-dimensional problem. Most of these physical effects occur at spatial scales too small to be explicitly resolved in the models. However, such a separation is not realistic as those processes are three-dimensional and interact with each other. Results from numerical weather prediction and climate models strongly suggest that subgrid-scale parameterizations represent a large source of model errors and sensitivities at a large computational cost. Improving the physical parameterizations and, in addition, reducing the fraction of the total computational time that they require is critical for improving the predictive skill of atmospheric models for both individual model realizations and for ensemble predictions. Our preliminary work presents a new methodology to incorporate parameterizations for use in atmospheric models. The effects of the parameterized physics on the diabatic heating and moistening/drying are incorporated into unified transfer functions, called Universal Look-Up Table (ULUT). The ULUT accepts as inputs the dependent variables and other information that are traditionally inserted into the parameterizations and produces the equivalent temperature and moisture changes that result from summing each parameterization. A similar concept using remotely-sensed data was proposed by Pielke Sr. et al. (2007) [Satellite-based model parameterization of diabatic heating. EOS, 88, 96-97].The major goal is to create a ULUT for the diabatic heating that would be able to reproduce the meteorological fields with the same accuracy as in the original model configuration but at a fraction of the cost. This effort is similar, although much broader in scope, to that of Leoncini et al. (2008, From model based parameterizations to Lookup Tables: An EOF approach. Wea. Forecasting, 23, 1127
10. The Parameterization of Solid Metal-Liquid Metal Partitioning of Siderophile Elements
NASA Technical Reports Server (NTRS)
Chabot, N. L.; Jones, J. H.
2003-01-01
The composition of a metallic liquid can significantly affect the partitioning behavior of elements. For example, some experimental solid metal-liquid metal partition coefficients have been shown to increase by three orders of magnitude with increasing S-content of the metallic liquid. Along with S, the presence of other light elements, such as P and C, has also been demonstrated to affect trace element partitioning behavior. Understanding the effects of metallic composition on partitioning behavior is important for modeling the crystallization of magmatic iron meteorites and the chemical effects of planetary differentiation. It is thus useful to have a mathematical expression that parameterizes the partition coefficient as a function of the composition of the metal. Here we present a revised parameterization method, which builds on the theory of the current parameterization of Jones and Malvin and which better handles partitioning in multi-light-element systems.
11. A numerical method for parameterization of atmospheric chemistry - Computation of tropospheric OH
NASA Technical Reports Server (NTRS)
Spivakovsky, C. M.; Wofsy, S. C.; Prather, M. J.
1990-01-01
An efficient and stable computational scheme for parameterization of atmospheric chemistry is described. The 24-hour-average concentration of OH is represented as a set of high-order polynomials in variables such as temperature, densities of H2O, CO, O3, and NO(t) (defined as NO + NO2 + NO3 + 2N2O5 + HNO2 + HNO4) as well as variables determining solar irradiance: cloud cover, density of the overhead ozone column, surface albedo, latitude, and solar declination. This parameterization of OH chemistry was used in the three-dimensional study of global distribution of CH3CCl3. The proposed computational scheme can be used for parameterization of rates of chemical production and loss or of any other output of a full chemical model.
12. Parameterization of the evaporation of rainfall for use in general circulation models
SciTech Connect
Feingold, G. )
1993-10-15
A parameterization of evaporation losses below cloud base is presented for use in general circulation models to assist in quantification of water content in the hydrological cycle. The scheme is based on detailed model calculations of the evolution of raindrop spectra below cloud base and includes the processes of collision coalescence/breakup. Evaporation is expressed as a percentage decrease in the liquid water ;mixing ratio, and the parameterization is formulated as an algebraic equation in (i) the cloud-base values o the mixing ratio and the drop concentration, (ii) the fall distance, and (iii) the lapse rate of temperature in the subcloud environment. Results show that when compared to the detailed model calculations, good estimates of evaporation (usually within 20% and often within 10%) are obtained for a wide range of conditions. An analysis of the errors in evaporation calculations associated with errors in the parameterization variables is performed. 29 refs., 34 figs., 3 tabs.
13. Parameterization of Forest Canopies with the PROSAIL Model
Austerberry, M. J.; Grigsby, S.; Ustin, S.
2013-12-01
Particularly in forested environments, arboreal characteristics such as Leaf Area Index (LAI) and Leaf Inclination Angle have a large impact on the spectral characteristics of reflected radiation. The reflected spectrum can be measured directly with satellites or airborne instruments, including the MASTER and AVIRIS instruments. This particular project dealt with spectral analysis of reflected light as measured by AVIRIS compared to tree measurements taken from the ground. Chemical properties of leaves including pigment concentrations and moisture levels were also measured. The leaf data was combined with the chemical properties of three separate trees, and served as input data for a sequence of simulations with the PROSAIL Model, a combination of PROSPECT and Scattering by Arbitrarily Inclined Leaves (SAIL) simulations. The output was a computed reflectivity spectrum, which corresponded to the spectra that were directly measured by AVIRIS for the three trees' exact locations within a 34-meter pixel resolution. The input data that produced the best-correlating spectral output was then cross-referenced with LAI values that had been obtained through two entirely separate methods, NDVI extraction and use of the Beer-Lambert law with airborne LiDAR. Examination with regressive techniques between the measured and modeled spectra then enabled a determination of the trees' probable structure and leaf parameters. Highly-correlated spectral output corresponded well to specific values of LAI and Leaf Inclination Angle. Interestingly, it appears that varying Leaf Angle Distribution has little or no noticeable effect on the PROSAIL model. Not only is the effectiveness and accuracy of the PROSAIL model evaluated, but this project is a precursor to direct measurement of vegetative indices exclusively from airborne or satellite observation.
14. Engelmann Spruce Site Index Models: A Comparison of Model Functions and Parameterizations
PubMed Central
Nigh, Gordon
2015-01-01
Engelmann spruce (Picea engelmannii Parry ex Engelm.) is a high-elevation species found in western Canada and western USA. As this species becomes increasingly targeted for harvesting, better height growth information is required for good management of this species. This project was initiated to fill this need. The objective of the project was threefold: develop a site index model for Engelmann spruce; compare the fits and modelling and application issues between three model formulations and four parameterizations; and more closely examine the grounded-Generalized Algebraic Difference Approach (g-GADA) model parameterization. The model fitting data consisted of 84 stem analyzed Engelmann spruce site trees sampled across the Engelmann Spruce – Subalpine Fir biogeoclimatic zone. The fitted models were based on the Chapman-Richards function, a modified Hossfeld IV function, and the Schumacher function. The model parameterizations that were tested are indicator variables, mixed-effects, GADA, and g-GADA. Model evaluation was based on the finite-sample corrected version of Akaike’s Information Criteria and the estimated variance. Model parameterization had more of an influence on the fit than did model formulation, with the indicator variable method providing the best fit, followed by the mixed-effects modelling (9% increase in the variance for the Chapman-Richards and Schumacher formulations over the indicator variable parameterization), g-GADA (optimal approach) (335% increase in the variance), and the GADA/g-GADA (with the GADA parameterization) (346% increase in the variance). Factors related to the application of the model must be considered when selecting the model for use as the best fitting methods have the most barriers in their application in terms of data and software requirements. PMID:25853472
15. Parameterization of aerodynamic roughness of China's land surface vegetation from remote sensing data
Hu, Deyong; Xing, Liwei; Huang, Shengli; Deng, Lei; Xu, Yingjun
2014-01-01
Aerodynamic roughness length (z0) is one of the important parameters that influence energy exchange at the land-atmosphere interface in numerical models, so it is of significance to accurately parameterize the land surface. To parameterize the z0 values of China's land surface vegetation using remote sensing data, we parameterized the vegetation canopy area index using the leaf area index and land cover products of moderate resolution imaging spectroradiometer data. Then we mapped the z0 values of different land cover types based on canopy area index and vegetation canopy height data. Finally, we analyzed the intra-annual monthly z0 values. The conclusions are: (1) This approach has been developed to parameterize large scale regional z0 values from multisource remote sensing data, allowing one to better model the land-atmosphere flux exchange based on this feasible and operational scheme. (2) The variation of z0 values in the parametric model is affected by the vegetation canopy area index and its threshold had been calculated to quantify different vegetation types. In general, the z0 value will increase during the growing season. When the threshold in the dense vegetation area or in the growing season is exceeded, the z0 values will decrease but the zero-plane displacement heights will increase. This technical scheme to parameterize the z0 can be applied to large-scale regions at a spatial resolution of 1 km, and the dynamic products of z0 can be used in high resolution land or atmospheric models to provide a useful scheme for land surface parameterization.
16. Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE
Schneider, Uwe; Hälg, Roger A.; Baiocco, Giorgio; Lomax, Tony
2016-08-01
The biological effectiveness of neutrons produced during proton therapy in inducing cancer is unknown, but potentially large. In particular, since neutron biological effectiveness is energy dependent, it is necessary to estimate, besides the dose, also the energy spectra, in order to obtain quantities which could be a measure of the biological effectiveness and test current models and new approaches against epidemiological studies on cancer induction after proton therapy. For patients treated with proton pencil beam scanning, this work aims to predict the spatially localized neutron energies, the effective quality factor, the weighting factor according to ICRP, and two RBE values, the first obtained from the saturation corrected dose mean lineal energy and the second from DSB cluster induction. A proton pencil beam was Monte Carlo simulated using GEANT. Based on the simulated neutron spectra for three different proton beam energies a parameterization of energy, quality factors and RBE was calculated. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed parameterizations in order to calculate the spatially localized neutron energy, quality factors and RBE for each treated patient. The parameterization represents the simple quantification of neutron energy in two energy bins and the quality factors and RBE with a satisfying precision up to 85 cm away from the proton pencil beam when compared to the results based on 3D Monte Carlo simulations. The root mean square error of the energy estimate between Monte Carlo simulation based results and the parameterization is 3.9%. For the quality factors and RBE estimates it is smaller than 0.9%. The model was successfully integrated into the PSI treatment planning system. It was found that the parameterizations for neutron energy, quality factors and RBE were independent of proton energy in the investigated energy range of interest for proton therapy. The pencil beam algorithm has
17. Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE.
PubMed
Schneider, Uwe; Hälg, Roger A; Baiocco, Giorgio; Lomax, Tony
2016-08-21
The biological effectiveness of neutrons produced during proton therapy in inducing cancer is unknown, but potentially large. In particular, since neutron biological effectiveness is energy dependent, it is necessary to estimate, besides the dose, also the energy spectra, in order to obtain quantities which could be a measure of the biological effectiveness and test current models and new approaches against epidemiological studies on cancer induction after proton therapy. For patients treated with proton pencil beam scanning, this work aims to predict the spatially localized neutron energies, the effective quality factor, the weighting factor according to ICRP, and two RBE values, the first obtained from the saturation corrected dose mean lineal energy and the second from DSB cluster induction. A proton pencil beam was Monte Carlo simulated using GEANT. Based on the simulated neutron spectra for three different proton beam energies a parameterization of energy, quality factors and RBE was calculated. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed parameterizations in order to calculate the spatially localized neutron energy, quality factors and RBE for each treated patient. The parameterization represents the simple quantification of neutron energy in two energy bins and the quality factors and RBE with a satisfying precision up to 85 cm away from the proton pencil beam when compared to the results based on 3D Monte Carlo simulations. The root mean square error of the energy estimate between Monte Carlo simulation based results and the parameterization is 3.9%. For the quality factors and RBE estimates it is smaller than 0.9%. The model was successfully integrated into the PSI treatment planning system. It was found that the parameterizations for neutron energy, quality factors and RBE were independent of proton energy in the investigated energy range of interest for proton therapy. The pencil beam algorithm has
18. Sub-grid Parameterization of Cumulus Vertical Velocities for Climate and Numerical Weather Prediction Models
Cooke, William; Donner, Leo
2015-04-01
Microphysical and aerosol processes determine the magnitude of climate forcing by aerosol-cloud interactions, are central aspects of cloud-climate feedback, and are important elements in weather systems for which accurate forecasting is a major goal of numerical weather prediction. Realistic simulation of these processes demands not only accurate microphysical and aerosol process representations but also realistic simulation of the vertical motions in which the aerosols and microphysics act. Aerosol activation, for example, is a strong function of vertical velocity. Cumulus parameterizations for climate and numerical weather prediction models have recently begun to include vertical velocities among the statistics they predict. These vertical velocities have been subject to only limited evaluation using observed vertical velocities. Deployments of multi-Doppler radars and dual-frequency profilers in recent field campaigns have substantially increased the observational base of cumulus vertical velocities, which for decades had been restricted mostly to GATE observations. Observations from TWP-ICE (Darwin, Australia) and MC3E (central United States) provide previously unavailable information on the vertical structure of cumulus vertical velocities and observations in differing synoptic contexts from those available in the past. They also provide an opportunity to independently evaluate cumulus parameterizations with vertical velocities tuned to earlier GATE observations. This presentation will compare vertical velocities observed in TWP-ICE and MC3E with cumulus vertical velocities using the parameterization in the GFDL CM3 climate model. Single-column results indicate parameterized vertical velocities are frequently greater than observed. Errors in parameterized vertical velocities exhibit similarities to vertical velocities explicitly simulated by cloud-system resolving models, and underlying issues in the treatment of microphysics may be important for both. The
19. Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE.
PubMed
Schneider, Uwe; Hälg, Roger A; Baiocco, Giorgio; Lomax, Tony
2016-08-21
The biological effectiveness of neutrons produced during proton therapy in inducing cancer is unknown, but potentially large. In particular, since neutron biological effectiveness is energy dependent, it is necessary to estimate, besides the dose, also the energy spectra, in order to obtain quantities which could be a measure of the biological effectiveness and test current models and new approaches against epidemiological studies on cancer induction after proton therapy. For patients treated with proton pencil beam scanning, this work aims to predict the spatially localized neutron energies, the effective quality factor, the weighting factor according to ICRP, and two RBE values, the first obtained from the saturation corrected dose mean lineal energy and the second from DSB cluster induction. A proton pencil beam was Monte Carlo simulated using GEANT. Based on the simulated neutron spectra for three different proton beam energies a parameterization of energy, quality factors and RBE was calculated. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed parameterizations in order to calculate the spatially localized neutron energy, quality factors and RBE for each treated patient. The parameterization represents the simple quantification of neutron energy in two energy bins and the quality factors and RBE with a satisfying precision up to 85 cm away from the proton pencil beam when compared to the results based on 3D Monte Carlo simulations. The root mean square error of the energy estimate between Monte Carlo simulation based results and the parameterization is 3.9%. For the quality factors and RBE estimates it is smaller than 0.9%. The model was successfully integrated into the PSI treatment planning system. It was found that the parameterizations for neutron energy, quality factors and RBE were independent of proton energy in the investigated energy range of interest for proton therapy. The pencil beam algorithm has
20. Effect of hygroscopic growth on the aerosol light-scattering coefficient: A review of measurements, techniques and error sources
Titos, G.; Cazorla, A.; Zieger, P.; Andrews, E.; Lyamani, H.; Granados-Muñoz, M. J.; Olmo, F. J.; Alados-Arboledas, L.
2016-09-01
Knowledge of the scattering enhancement factor, f(RH), is important for an accurate description of direct aerosol radiative forcing. This factor is defined as the ratio between the scattering coefficient at enhanced relative humidity, RH, to a reference (dry) scattering coefficient. Here, we review the different experimental designs used to measure the scattering coefficient at dry and humidified conditions as well as the procedures followed to analyze the measurements. Several empirical parameterizations for the relationship between f(RH) and RH have been proposed in the literature. These parameterizations have been reviewed and tested using experimental data representative of different hygroscopic growth behavior and a new parameterization is presented. The potential sources of error in f(RH) are discussed. A Monte Carlo method is used to investigate the overall measurement uncertainty, which is found to be around 20-40% for moderately hygroscopic aerosols. The main factors contributing to this uncertainty are the uncertainty in RH measurement, the dry reference state and the nephelometer uncertainty. A literature survey of nephelometry-based f(RH) measurements is presented as a function of aerosol type. In general, the highest f(RH) values were measured in clean marine environments, with pollution having a major influence on f(RH). Dust aerosol tended to have the lowest reported hygroscopicity of any of the aerosol types studied. Major open questions and suggestions for future research priorities are outlined.
1. Matching Pursuit with Asymmetric Functions for Signal Decomposition and Parameterization
PubMed Central
Spustek, Tomasz; Jedrzejczak, Wiesław Wiktor; Blinowska, Katarzyna Joanna
2015-01-01
The method of adaptive approximations by Matching Pursuit makes it possible to decompose signals into basic components (called atoms). The approach relies on fitting, in an iterative way, functions from a large predefined set (called dictionary) to an analyzed signal. Usually, symmetric functions coming from the Gabor family (sine modulated Gaussian) are used. However Gabor functions may not be optimal in describing waveforms present in physiological and medical signals. Many biomedical signals contain asymmetric components, usually with a steep rise and slower decay. For the decomposition of this kind of signal we introduce a dictionary of functions of various degrees of asymmetry – from symmetric Gabor atoms to highly asymmetric waveforms. The application of this enriched dictionary to Otoacoustic Emissions and Steady-State Visually Evoked Potentials demonstrated the advantages of the proposed method. The approach provides more sparse representation, allows for correct determination of the latencies of the components and removes the "energy leakage" effect generated by symmetric waveforms that do not sufficiently match the structures of the analyzed signal. Additionally, we introduced a time-frequency-amplitude distribution that is more adequate for representation of asymmetric atoms than the conventional time-frequency-energy distribution. PMID:26115480
2. RedMDStream: Parameterization and Simulation Toolbox for Coarse-Grained Molecular Dynamics Models
PubMed Central
Leonarski, Filip; Trylska, Joanna
2015-01-01
Coarse-grained (CG) models in molecular dynamics (MD) are powerful tools to simulate the dynamics of large biomolecular systems on micro- to millisecond timescales. However, the CG model, potential energy terms, and parameters are typically not transferable between different molecules and problems. So parameterizing CG force fields, which is both tedious and time-consuming, is often necessary. We present RedMDStream, a software for developing, testing, and simulating biomolecules with CG MD models. Development includes an automatic procedure for the optimization of potential energy parameters based on metaheuristic methods. As an example we describe the parameterization of a simple CG MD model of an RNA hairpin. PMID:25902423
3. Multiscale Modeling of Grain-Boundary Fracture: Cohesive Zone Models Parameterized From Atomistic Simulations
NASA Technical Reports Server (NTRS)
Glaessgen, Edward H.; Saether, Erik; Phillips, Dawn R.; Yamakov, Vesselin
2006-01-01
A multiscale modeling strategy is developed to study grain boundary fracture in polycrystalline aluminum. Atomistic simulation is used to model fundamental nanoscale deformation and fracture mechanisms and to develop a constitutive relationship for separation along a grain boundary interface. The nanoscale constitutive relationship is then parameterized within a cohesive zone model to represent variations in grain boundary properties. These variations arise from the presence of vacancies, intersticies, and other defects in addition to deviations in grain boundary angle from the baseline configuration considered in the molecular dynamics simulation. The parameterized cohesive zone models are then used to model grain boundaries within finite element analyses of aluminum polycrystals.
4. Simple parameterized coordinate transformation method for deep- and smooth-profile gratings.
PubMed
Xu, Xihong; Li, Lifeng
2014-12-01
A simple variable transformation that consists of two joined straight-line segments per grating period is proposed for the parameterized coordinate transformation method (the C method). With this bilinear parameterization, the C method can produce convergent numerical results for gratings of deep and smooth profiles with a groove depth-to-period ratio as high as 10, which to date has been far out of reach of the C method. The danger of getting divergent results due to inadvertently using an overly large truncation number is also practically eliminated.
5. Calculates Thermal Neutron Scattering Kernel.
1989-11-10
Version 00 THRUSH computes the thermal neutron scattering kernel by the phonon expansion method for both coherent and incoherent scattering processes. The calculation of the coherent part is suitable only for calculating the scattering kernel for heavy water.
6. Parameterization and analysis of 3-D radiative transfer in clouds
SciTech Connect
Varnai, Tamas
2012-03-16
7. Why different gas flux velocity parameterizations result in so similar flux results in the North Atlantic?
Piskozub, Jacek; Wróbel, Iwona
2016-04-01
The North Atlantic is a crucial region for both ocean circulation and the carbon cycle. Most of ocean deep waters are produced in the basin making it a large CO2 sink. The region, close to the major oceanographic centres has been well covered with cruises. This is why we have performed a study of net CO2 flux dependence upon the choice of gas transfer velocity k parameterization for this very region: the North Atlantic including European Arctic Seas. The study has been a part of a ESA funded OceanFlux GHG Evolution project and, at the same time, a PhD thesis (of I.W) funded by Centre of Polar Studies "POLAR-KNOW" (a project of the Polish Ministry of Science). Early results have been presented last year at EGU 2015 as a PICO presentation EGU2015-11206-1. We have used FluxEngine, a tool created within an earlier ESA funded project (OceanFlux Greenhouse Gases) to calculate the North Atlantic and global fluxes with different gas transfer velocity formulas. During the processing of the data, we have noticed that the North Atlantic results for different k formulas are more similar (in the sense of relative error) that global ones. This was true both for parameterizations using the same power of wind speed and when comparing wind squared and wind cubed parameterizations. This result was interesting because North Atlantic winds are stronger than the global average ones. Was the flux result similarity caused by the fact that the parameterizations were tuned to the North Atlantic area where many of the early cruises measuring CO2 fugacities were performed? A closer look at the parameterizations and their history showed that not all of them were based on North Atlantic data. Some of them were tuned to the South Ocean with even stronger winds while some were based on global budgets of 14C. However we have found two reasons, not reported before in the literature, for North Atlantic fluxes being more similar than global ones for different gas transfer velocity parametrizations
8. Parameterizations of Cloud Microphysics and Indirect Aerosol Effects
SciTech Connect
Tao, Wei-Kuo
2014-05-19
/hail. Each type is described by a special size distribution function containing 33 categories (bins). Atmospheric aerosols are also described using number density size-distribution functions (containing 33 bins). Droplet nucleation (activation) is derived from the analytical calculation of super-saturation, which is used to determine the sizes of aerosol particles to be activated and the corresponding sizes of nucleated droplets. Primary nucleation of each type of ice crystal takes place within certain temperature ranges. A detailed description of these explicitly parameterized processes can be found in Khain and Sednev (1996) and Khain et al. (1999, 2001). 2.3 Case Studies Three cases, a tropical oceanic squall system observed during TOGA COARE (Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment, which occurred over the Pacific Ocean warm pool from November 1992 to February 1993), a midlatitude continental squall system observed during PRESTORM (Preliminary Regional Experiment for STORM-Central, which occurred in Kansas and Oklahoma during May-June 1985), and mid-afternoon convection observed during CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and Cirrus Layers – Florida Area Cumulus Experiment, which occurred in Florida during July 2002), will be used to examine the impact of aerosols on deep, precipitating systems. 3. SUMMARY of RESULTS • For all three cases, higher CCN produces smaller cloud droplets and a narrower spectrum. Dirty conditions delay rain formation, increase latent heat release above the freezing level, and enhance vertical velocities at higher altitude for all cases. Stronger updrafts, deeper mixed-phase regions, and more ice particles are simulated with higher CCN in good agreement with observations. • In all cases, rain reaches the ground early with lower CCN. Rain suppression is also evident in all three cases with high CCN in good agreement with observations (Rosenfeld, 1999, 2000 and others). Rain
9. Final Technical Report for "Ice nuclei relation to aerosol properties: Data analysis and model parameterization for IN in mixed-phase clouds" (DOE/SC00002354)
SciTech Connect
Anthony Prenni; Kreidenweis, Sonia M.
2012-09-28
Clouds play an important role in weather and climate. In addition to their key role in the hydrologic cycle, clouds scatter incoming solar radiation and trap infrared radiation from the surface and lower atmosphere. Despite their importance, feedbacks involving clouds remain as one of the largest sources of uncertainty in climate models. To better simulate cloud processes requires better characterization of cloud microphysical processes, which can affect the spatial extent, optical depth and lifetime of clouds. To this end, we developed a new parameterization to be used in numerical models that describes the variation of ice nuclei (IN) number concentrations active to form ice crystals in mixed-phase (water droplets and ice crystals co-existing) cloud conditions as these depend on existing aerosol properties and temperature. The parameterization is based on data collected using the Colorado State University continuous flow diffusion chamber in aircraft and ground-based campaigns over a 14-year period, including data from the DOE-supported Mixed-Phase Arctic Cloud Experiment. The resulting relationship is shown to more accurately represent the variability of ice nuclei distributions in the atmosphere compared to currently used parameterizations based on temperature alone. When implemented in one global climate model, the new parameterization predicted more realistic annually averaged cloud water and ice distributions, and cloud radiative properties, especially for sensitive higher latitude mixed-phase cloud regions. As a test of the new global IN scheme, it was compared to independent data collected during the 2008 DOE-sponsored Indirect and Semi-Direct Aerosol Campaign (ISDAC). Good agreement with this new data set suggests the broad applicability of the new scheme for describing general (non-chemically specific) aerosol influences on IN number concentrations feeding mixed-phase Arctic stratus clouds. Finally, the parameterization was implemented into a regional
10. Alternative parameterizations of relatedness in whole genome association analysis of pre-weaning traits of Nelore-Angus calves
PubMed Central
Riley, David G.; Gill, Clare A.; Herring, Andy D.; Riggs, Penny K.; Sawyer, Jason E.; Sanders, James O.
2014-01-01
Gestation length, birth weight, and weaning weight of F2 Nelore-Angus calves (n = 737) with designed extensive full-sibling and half-sibling relatedness were evaluated for association with 34,957 SNP markers. In analyses of birth weight, random relatedness was modeled three ways: 1) none, 2) random animal, pedigree-based relationship matrix, or 3) random animal, genomic relationship matrix. Detected birth weight-SNP associations were 1,200, 735, and 31 for those parameterizations respectively; each additional model refinement removed associations that apparently were a result of the built-in stratification by relatedness. Subsequent analyses of gestation length and weaning weight modeled genomic relatedness; there were 40 and 26 trait-marker associations detected for those traits, respectively. Birth weight associations were on BTA14 except for a single marker on BTA5. Gestation length associations included 37 SNP on BTA21, 2 on BTA27 and one on BTA3. Weaning weight associations were on BTA14 except for a single marker on BTA10. Twenty-one SNP markers on BTA14 were detected in both birth and weaning weight analyses. PMID:25249774
Morris, C. L.
2015-12-01
Cosmic ray muons are ubiquitous, are highly penetrating, and can be used to measure material densities by either measuring the stopping rate or by measuring the scattering of transmitted muons. The Los Alamos team has studied scattering radiography for a number of applications. Some results will be shown of scattering imaging for a range of practical applications, and estimates will be made of the utility of scattering radiography for nondestructive assessments of large structures and for geological surveying. Results of imaging the core of the Toshiba Nuclear Critical Assembly (NCA) Reactor in Kawasaki, Japan and simulations of imaging the damaged cores of the Fukushima nuclear reactors will be presented. Below is an image made using muons of a core configuration for the NCA reactor.
12. Intra-beam scattering
Piwinski, A.
Intra-beam scattering is analysed and the rise times or damping times of the beam dimensions are derived. The theoretical results are compared with experimental values obtained on the CERN AA and SPS machines.
SciTech Connect
Thoreson, Gregory G.; Mitchell, Dean J; Theisen, Lisa Anne; Harding, Lee T.
2013-09-01
Radiation transport calculations were performed to compute the angular tallies for scattered gamma-rays as a function of distance, height, and environment. Greens Functions were then used to encapsulate the results a reusable transformation function. The calculations represent the transport of photons throughout scattering surfaces that surround sources and detectors, such as the ground and walls. Utilization of these calculations in GADRAS (Gamma Detector Response and Analysis Software) enables accurate computation of environmental scattering for a variety of environments and source configurations. This capability, which agrees well with numerous experimental benchmark measurements, is now deployed with GADRAS Version 18.2 as the basis for the computation of scattered radiation.
14. Rayleigh Scattering Diagnostics Workshop
NASA Technical Reports Server (NTRS)
Seasholtz, Richard (Compiler)
1996-01-01
The Rayleigh Scattering Diagnostics Workshop was held July 25-26, 1995 at the NASA Lewis Research Center in Cleveland, Ohio. The purpose of the workshop was to foster timely exchange of information and expertise acquired by researchers and users of laser based Rayleigh scattering diagnostics for aerospace flow facilities and other applications. This Conference Publication includes the 12 technical presentations and transcriptions of the two panel discussions. The first panel was made up of 'users' of optical diagnostics, mainly in aerospace test facilities, and its purpose was to assess areas of potential applications of Rayleigh scattering diagnostics. The second panel was made up of active researchers in Rayleigh scattering diagnostics, and its purpose was to discuss the direction of future work.
15. CONTINUOUS ROTATION SCATTERING CHAMBER
DOEpatents
Verba, J.W.; Hawrylak, R.A.
1963-08-01
An evacuated scattering chamber for use in observing nuclear reaction products produced therein over a wide range of scattering angles from an incoming horizontal beam that bombards a target in the chamber is described. A helically moving member that couples the chamber to a detector permits a rapid and broad change of observation angles without breaching the vacuum in the chamber. Also, small inlet and outlet openings are provided whose size remains substantially constant. (auth)
16. Positron-rubidium scattering
NASA Technical Reports Server (NTRS)
Mceachran, R. P.; Horbatsch, M.; Stauffer, A. D.
1990-01-01
A 5-state close-coupling calculation (5s-5p-4d-6s-6p) was carried out for positron-Rb scattering in the energy range 3.7 to 28.0 eV. In contrast to the results of similar close-coupling calculations for positron-Na and positron-K scattering the (effective) total integrated cross section has an energy dependence which is contrary to recent experimental measurements.
17. Parameterization of unresolved obstacles in wave modelling: A source term approach
Mentaschi, L.; Pérez, J.; Besio, G.; Mendez, F. J.; Menendez, M.
2015-12-01
In the present work we introduce two source terms for the parameterization of energy dissipation due to unresolved obstacles in spectral wave models. The proposed approach differs from the classical one based on spatial propagation schemes because it provides a local representation of phenomena such as unresolved wave energy dissipation. This source term-based approach presents the advantage of decoupling unresolved obstacles parameterization from the spatial propagation scheme, allowing not to reformulate, reimplement and revalidate the parameterization of unresolved obstacles for each propagation scheme. Furthermore it opens the way to parameterizations of other unresolved sheltering effects like rotation and redistribution of wave energy over frequencies. Proposed source terms estimate respectively local energy dissipation and shadow effect due to unresolved obstacles. Source terms validation through synthetic case studies has been carried out, showing their ability in reproducing wave dynamics comparable to those of high resolution models. The analysis of high resolution stationary wave simulations may help to better diagnose and study the effects of unresolved obstacles, providing estimations of transparency coefficients for each spectral component and allowing to understand and model unresolved effects of rotation and redistribution of wave energy over frequencies.
18. Regularized kernel PCA for the efficient parameterization of complex geological models
Vo, Hai X.; Durlofsky, Louis J.
2016-10-01
The use of geological parameterization procedures enables high-fidelity geomodels to be represented in terms of relatively few variables. Such parameterizations are particularly useful when the subspace representation is constructed to implicitly capture the key geological features that appear in prior geostatistical realizations. In this case, the parameterization can be used very effectively within a data assimilation framework. In this paper, we extend and apply geological parameterization techniques based on kernel principal component analysis (KPCA) for the representation of complex geomodels characterized by non-Gaussian spatial statistics. KPCA involves the application of PCA in a high-dimensional feature space and the subsequent reverse mapping of the feature-space model back to physical space. This reverse mapping, referred to as the pre-image problem, can be challenging because it (formally) involves a nonlinear minimization. In this work, a new explicit pre-image procedure, which avoids many of the problems with existing approaches, is introduced. To achieve (ensemble-level) flow responses in close agreement with those from reference geostatistical realizations, a bound-constrained, regularized version of KPCA, referred to as R-KPCA, is also introduced. R-KPCA can be viewed as a post-processing of realizations generated using KPCA. The R-KPCA representation is incorporated into an adjoint-gradient-based data assimilation procedure, and its use for history matching a complex deltaic fan system is demonstrated. Matlab code for the KPCA and R-KPCA procedures is provided online as Supplementary Material.
19. IMPLEMENTATION OF AN URBAN CANOPY PARAMETERIZATION FOR FINE-SCALE SIMULATIONS
EPA Science Inventory
The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) (Grell et al. 1994) has been modified to include an urban canopy parameterization (UCP) for fine-scale urban simulations ( 1 - km horizontal grid spacing ). The UCP accounts for dr...
20. Parameterizing the Transport Pathways for Cell Invasion in Complex Scaffold Architectures.
PubMed
Ashworth, Jennifer C; Mehr, Marco; Buxton, Paul G; Best, Serena M; Cameron, Ruth E
2016-05-01
Interconnecting pathways through porous tissue engineering scaffolds play a vital role in determining nutrient supply, cell invasion, and tissue ingrowth. However, the global use of the term "interconnectivity" often fails to describe the transport characteristics of these pathways, giving no clear indication of their potential to support tissue synthesis. This article uses new experimental data to provide a critical analysis of reported methods for the description of scaffold transport pathways, ranging from qualitative image analysis to thorough structural parameterization using X-ray Micro-Computed Tomography. In the collagen scaffolds tested in this study, it was found that the proportion of pore space perceived to be accessible dramatically changed depending on the chosen method of analysis. Measurements of % interconnectivity as defined in this manner varied as a function of direction and connection size, and also showed a dependence on measurement length scale. As an alternative, a method for transport pathway parameterization was investigated, using percolation theory to calculate the diameter of the largest sphere that can travel to infinite distance through a scaffold in a specified direction. As proof of principle, this approach was used to investigate the invasion behavior of primary fibroblasts in response to independent changes in pore wall alignment and pore space accessibility, parameterized using the percolation diameter. The result was that both properties played a distinct role in determining fibroblast invasion efficiency. This example therefore demonstrates the potential of the percolation diameter as a method of transport pathway parameterization, to provide key structural criteria for application-based scaffold design.
1. Integrated cumulus ensemble and turbulence (ICET): An integrated parameterization system for general circulation models (GCMs)
SciTech Connect
Evans, J.L.; Frank, W.M.; Young, G.S.
1996-04-01
Successful simulations of the global circulation and climate require accurate representation of the properties of shallow and deep convective clouds, stable-layer clouds, and the interactions between various cloud types, the boundary layer, and the radiative fluxes. Each of these phenomena play an important role in the global energy balance, and each must be parameterized in a global climate model. These processes are highly interactive. One major problem limiting the accuracy of parameterizations of clouds and other processes in general circulation models (GCMs) is that most of the parameterization packages are not linked with a common physical basis. Further, these schemes have not, in general, been rigorously verified against observations adequate to the task of resolving subgrid-scale effects. To address these problems, we are designing a new Integrated Cumulus Ensemble and Turbulence (ICET) parameterization scheme, installing it in a climate model (CCM2), and evaluating the performance of the new scheme using data from Atmospheric Radiation Measurement (ARM) Program Cloud and Radiation Testbed (CART) sites.
2. SPACS: A semi-empirical parameterization for isotopic spallation cross sections
Schmitt, C.; Schmidt, K.-H.; Kelić-Heil, A.
2014-12-01
A new semi-empirical parameterization for residue cross sections in spallation reactions is presented. The prescription named SPACS, for spallation cross sections, permits calculating the fragment production in proton- and neutron-induced collisions with light up to heavy non-fissile partners from the Fermi regime to ultra-relativistic energies. The model is fully analytical, based on a new parameterization of the mass yields, accounting for the dependence on bombarding energy. The formalism for the isobaric distribution consists of a commonly used functional form, borrowed from the empirical parameterization of fragmentation cross sections EPAX, with the observed suited adjustments for spallation, and extended to the charge-pickup channel. Structural and even-odd staggering related to the last stage of the primary-residue deexcitation process is additionally explicitly introduced with a new prescription. Calculations are benchmarked with recent data collected at GSI, Darmstadt as well as with previous measurements employing various techniques. The dependences observed experimentally on collision energy, reaction-partner mass, and proton-neutron asymmetry are well described. A fast analytical parameterization, such as SPACS, can be relevant to be implemented in complex simulations as used for practical issues at nuclear facilities and plants. Its predictive power also makes it useful for cross-section estimates in astrophysics and biophysics.
3. Impact of APEX parameterization and soil data on runoff, sediment, and nutrients transport assessment
Technology Transfer Automated Retrieval System (TEKTRAN)
Hydrological models have become essential tools for environmental assessments. This study’s objective was to evaluate a best professional judgment (BPJ) parameterization of the Agricultural Policy and Environmental eXtender (APEX) model with soil-survey data against the calibrated model with either ...
4. Creating a parameterized model of a CMOS transistor with a gate of enclosed layout
Vinogradov, S. M.; Atkin, E. V.; Ivanov, P. Y.
2016-02-01
The method of creating a parameterized spice model of an N-channel transistor with a gate of enclosed layout is considered. Formulas and examples of engineering calculations for use of models in the computer-aided Design environment of Cadence Vitruoso are presented. Calculations are made for the CMOS technology with 180 nm design rules of the UMC.
5. A Dynamically Computed Convective Time Scale for the Kain–Fritsch Convective Parameterization Scheme
EPA Science Inventory
Many convective parameterization schemes define a convective adjustment time scale τ as the time allowed for dissipation of convective available potential energy (CAPE). The Kain–Fritsch scheme defines τ based on an estimate of the advective time period for deep con...
6. A configurable B-spline parameterization method for structural optimization of wing boxes
Yu, Alan Tao
2009-12-01
This dissertation presents a synthesis of methods for structural optimization of aircraft wing boxes. The optimization problem considered herein is the minimization of structural weight with respect to component sizes, subject to stress constraints. Different aspects of structural optimization methods representing the current state-of-the-art are discussed, including sequential quadratic programming, sensitivity analysis, parameterization of design variables, constraint handling, and multiple load treatment. Shortcomings of the current techniques are identified and a B-spline parameterization representing the structural sizes is proposed to address them. A new configurable B-spline parameterization method for structural optimization of wing boxes is developed that makes it possible to flexibly explore design spaces. An automatic scheme using different levels of B-spline parameterization configurations is also proposed, along with a constraint aggregation method in order to reduce the computational effort. Numerical results are compared to evaluate the effectiveness of the B-spline approach and the constraint aggregation method. To evaluate the new formulations and explore design spaces, the wing box of an airliner is optimized for the minimum weight subject to stress constraints under multiple load conditions. The new approaches are shown to significantly reduce the computational time required to perform structural optimization and to yield designs that are more realistic than existing methods.
7. Parameterization of the GPFARM-Range model for simulating rangeland productivity
Technology Transfer Automated Retrieval System (TEKTRAN)
One of the major limitations to rangeland model usage is the lack of parameter values appropriate for reliable simulations at different locations and times. In this chapter we seek to show how the GPFARM-Range, a rangeland model, which has been previously parameterized, tested and validated for the ...
Dremin, I. M.
2013-01-01
Colliding high-energy hadrons either produce new particles or scatter elastically with their quantum numbers conserved and no other particles produced. We consider the latter case here. Although inelastic processes dominate at high energies, elastic scattering contributes considerably (18-25%) to the total cross section. Its share first decreases and then increases at higher energies. Small-angle scattering prevails at all energies. Some characteristic features can be seen that provide information on the geometrical structure of the colliding particles and the relevant dynamical mechanisms. The steep Gaussian peak at small angles is followed by the exponential (Orear) regime with some shoulders and dips, and then by a power-law decrease. Results from various theoretical approaches are compared with experimental data. Phenomenological models claiming to describe this process are reviewed. The unitarity condition predicts an exponential fall for the differential cross section with an additional substructure to occur exactly between the low momentum transfer diffraction cone and a power-law, hard parton scattering regime under high momentum transfer. Data on the interference of the Coulomb and nuclear parts of amplitudes at extremely small angles provide the value of the real part of the forward scattering amplitude. The real part of the elastic scattering amplitude and the contribution of inelastic processes to the imaginary part of this amplitude (the so-called overlap function) are also discussed. Problems related to the scaling behavior of the differential cross section are considered. The power-law regime at highest momentum transfer is briefly described.
9. Effective Tree Scattering at L-Band
NASA Technical Reports Server (NTRS)
Kurum, Mehmet; ONeill, Peggy E.; Lang, Roger H.; Joseph, Alicia T.; Cosh, Michael H.; Jackson, Thomas J.
2011-01-01
For routine microwave Soil Moisture (SM) retrieval through vegetation, the tau-omega [1] model [zero-order Radiative Transfer (RT) solution] is attractive due to its simplicity and eases of inversion and implementation. It is the model used in baseline retrieval algorithms for several planned microwave space missions, such as ESA's Soil Moisture Ocean Salinity (SMOS) mission (launched November 2009) and NASA's Soil Moisture Active Passive (SMAP) mission (to be launched 2014/2015) [2 and 3]. These approaches are adapted for vegetated landscapes with effective vegetation parameters tau and omega by fitting experimental data or simulation outputs of a multiple scattering model [4-7]. The model has been validated over grasslands, agricultural crops, and generally light to moderate vegetation. As the density of vegetation increases, sensitivity to the underlying SM begins to degrade significantly and errors in the retrieved SM increase accordingly. The zero-order model also loses its validity when dense vegetation (i.e. forest, mature corn, etc.) includes scatterers, such as branches and trunks (or stalks in the case of corn), which are large with respect to the wavelength. The tau-omega model (when applied over moderately to densely vegetated landscapes) will need modification (in terms of form or effective parameterization) to enable accurate characterization of vegetation parameters with respect to specific tree types, anisotropic canopy structure, presence of leaves and/or understory. More scattering terms (at least up to first-order at L-band) should be included in the RT solutions for forest canopies [8]. Although not really suitable to forests, a zero-order tau-omega model might be applied to such vegetation canopies with large scatterers, but that equivalent or effective parameters would have to be used [4]. This requires that the effective values (vegetation opacity and single scattering albedo) need to be evaluated (compared) with theoretical definitions of
10. Parameterization of ALMANAC crop simulation model for non-irrigated dry bean in semi-arid temperate areas in Mexico
Technology Transfer Automated Retrieval System (TEKTRAN)
Simulation models can be used to make management decisions when properly parameterized. This study aimed to parameterize the ALMANAC (Agricultural Land Management Alternatives with Numerical Assessment Criteria) crop simulation model for dry bean in the semi-arid temperate areas of Mexico. The par...
11. An Evaluation of Lightning Flash Rate Parameterizations Based on Observations of Colorado Storms during DC3
Basarab, B.; Fuchs, B.; Rutledge, S. A.
2013-12-01
Predicting lightning activity in thunderstorms is important in order to accurately quantify the production of nitrogen oxides (NOx = NO + NO2) by lightning (LNOx). Lightning is an important global source of NOx, and since NOx is a chemical precursor to ozone, the climatological impacts of LNOx could be significant. Many cloud-resolving models rely on parameterizations to predict lightning and LNOx since the processes leading to charge separation and lightning discharge are not yet fully understood. This study evaluates predicted flash rates based on existing lightning parameterizations against flash rates observed for Colorado storms during the Deep Convective Clouds and Chemistry Experiment (DC3). Evaluating lightning parameterizations against storm observations is a useful way to possibly improve the prediction of flash rates and LNOx in models. Additionally, since convective storms that form in the eastern plains of Colorado can be different thermodynamically and electrically from storms in other regions, it is useful to test existing parameterizations against observations from these storms. We present an analysis of the dynamics, microphysics, and lightning characteristics of two case studies, severe storms that developed on 6 and 7 June 2012. This analysis includes dual-Doppler derived horizontal and vertical velocities, a hydrometeor identification based on polarimetric radar variables using the CSU-CHILL radar, and insight into the charge structure using observations from the northern Colorado Lightning Mapping Array (LMA). Flash rates were inferred from the LMA data using a flash counting algorithm. We have calculated various microphysical and dynamical parameters for these storms that have been used in empirical flash rate parameterizations. In particular, maximum vertical velocity has been used to predict flash rates in some cloud-resolving chemistry simulations. We diagnose flash rates for the 6 and 7 June storms using this parameterization and compare
12. Sensitivity of the recent methane budget to LMDz sub-grid-scale physical parameterizations
Locatelli, R.; Bousquet, P.; Saunois, M.; Chevallier, F.; Cressot, C.
2015-09-01
With the densification of surface observing networks and the development of remote sensing of greenhouse gases from space, estimations of methane (CH4) sources and sinks by inverse modeling are gaining additional constraining data but facing new challenges. The chemical transport model (CTM) linking the flux space to methane mixing ratio space must be able to represent these different types of atmospheric constraints for providing consistent flux estimations. Here we quantify the impact of sub-grid-scale physical parameterization errors on the global methane budget inferred by inverse modeling. We use the same inversion setup but different physical parameterizations within one CTM. Two different schemes for vertical diffusion, two others for deep convection, and one additional for thermals in the planetary boundary layer (PBL) are tested. Different atmospheric methane data sets are used as constraints (surface observations or satellite retrievals). At the global scale, methane emissions differ, on average, from 4.1 Tg CH4 per year due to the use of different sub-grid-scale parameterizations. Inversions using satellite total-column mixing ratios retrieved by GOSAT are less impacted, at the global scale, by errors in physical parameterizations. Focusing on large-scale atmospheric transport, we show that inversions using the deep convection scheme of Emanuel (1991) derive smaller interhemispheric gradients in methane emissions, indicating a slower interhemispheric exchange. At regional scale, the use of different sub-grid-scale parameterizations induces uncertainties ranging from 1.2 % (2.7 %) to 9.4 % (14.2 %) of methane emissions when using only surface measurements from a background (or an extended) surface network. Moreover, spatial distribution of methane emissions at regional scale can be very different, depending on both the physical parameterizations used for the modeling of the atmospheric transport and the observation data sets used to constrain the inverse
13. Parameterization of plume chemistry into large-scale atmospheric models: Application to aircraft NOx emissions
Cariolle, D.; Caro, D.; Paoli, R.; Hauglustaine, D. A.; CuéNot, B.; Cozic, A.; Paugam, R.
2009-10-01
A method is presented to parameterize the impact of the nonlinear chemical reactions occurring in the plume generated by concentrated NOx sources into large-scale models. The resulting plume parameterization is implemented into global models and used to evaluate the impact of aircraft emissions on the atmospheric chemistry. Compared to previous approaches that rely on corrected emissions or corrective factors to account for the nonlinear chemical effects, the present parameterization is based on the representation of the plume effects via a fuel tracer and a characteristic lifetime during which the nonlinear interactions between species are important and operate via rates of conversion for the NOx species and an effective reaction rates for O3. The implementation of this parameterization insures mass conservation and allows the transport of emissions at high concentrations in plume form by the model dynamics. Results from the model simulations of the impact on atmospheric ozone of aircraft NOx emissions are in rather good agreement with previous work. It is found that ozone production is decreased by 10 to 25% in the Northern Hemisphere with the largest effects in the north Atlantic flight corridor when the plume effects on the global-scale chemistry are taken into account. These figures are consistent with evaluations made with corrected emissions, but regional differences are noticeable owing to the possibility offered by this parameterization to transport emitted species in plume form prior to their dilution at large scale. This method could be further improved to make the parameters used by the parameterization function of the local temperature, humidity and turbulence properties diagnosed by the large-scale model. Further extensions of the method can also be considered to account for multistep dilution regimes during the plume dissipation. Furthermore, the present parameterization can be adapted to other types of point-source NOx emissions that have to be
14. Evaluating the Role of Aerosol Mixing State in Cloud Droplet Nucleation using a New Activation Parameterization
Rothenberg, D. A.; Wang, C.
2013-12-01
An important source contributing to uncertainty in simulations with global climate models arises from the influence of aerosols on cloud properties. These so-called aerosol indirect effects arise from a single coupling in the model, representing how aerosols activate and serve as cloud condensation nuclei and ultimately cloud droplets. While it is possible to build explicit numerical models which describe this process in detail, these class of tools are untenable for use in global climate models due to their complexity. Instead, physically- or empirically-based parameterizations of activation are used in their place to efficiently approximate cloud droplet nucleation as a function of a few meteorological and aerosol physical/chemical properties. As global climate models are outfitted with more complex, size- and mixing state-resolving aerosol models, activation parameterizations are increasingly called upon to handle aerosol populations against which their performance has not been explicitly benchmarked. Here, a simple scheme is proposed to evaluate the performance of activation parameterizations against a spectrum of mixing states, and two schemes commonly used in global models are studied using this framework. It is shown that each scheme exhibits systematic biases when a complex mixing state is present. To help resolve these issues, a new scheme is derived using Polynomial Chaos Expansion to build meta-models representing a full complexity parcel model. The meta-models are shown to accurately handle activation in both single-mode and mixture cases. In addition, a global sensitivity analysis is applied to benchmark the performance of the meta-models and the activation parameterizations against a detailed parcel model, and it is shown that the meta-models tend to more accurately attribute variability in activation dynamics to each input parameter and their interactions with others when compared to the physically-based parameterizations. A variety of experiments
15. Dam removal increases American eel abundance in distant headwater streams
USGS Publications Warehouse
Hitt, Nathaniel P.; Eyler, Sheila; Wofford, John E.B.
2012-01-01
American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwater streams increased significantly after the removal of Embrey Dam. Observed eel abundances after dam removal exceeded predictions derived from autoregressive models parameterized with data prior to dam removal. Mann–Kendall analyses also revealed consistent increases in eel abundances from 2004 to 2010 but inconsistent temporal trends before dam removal. Increasing eel numbers could not be attributed to changes in local physical habitat (i.e., mean stream depth or substrate size) or regional population dynamics (i.e., abundances in Maryland streams or Virginia estuaries). Dam removal was associated with decreasing minimum eel lengths in headwater streams, suggesting that the dam previously impeded migration of many small-bodied individuals (<300 mm TL). We hypothesize that restoring connectivity to headwater streams could increase eel population growth rates by increasing female eel numbers and fecundity. This study demonstrated that dams may influence eel abundances in headwater streams up to 150 river kilometers distant, and that dam removal may provide benefits for eel management and conservation at the landscape scale.
16. Effect of physical parameterization schemes on track and intensity of cyclone LAILA using WRF model
Kanase, Radhika D.; Salvekar, P. S.
2015-08-01
The objective of the present study is to investigate in detail the sensitivity of cumulus parameterization (CP), planetary boundary layer (PBL) parameterization, microphysics parameterization (MP) on the numerical simulation of severe cyclone LAILA over Bay of Bengal using Weather Research & Forecasting (WRF) model. The initial and boundary conditions are supplied from GFS data of 1° × 1° resolution and the model is integrated in three twoway' interactive nested domains at resolutions of 60 km, 20 km and 6.6 km. Total three sets of experiments are performed. First set of experiments include sensitivity of Cumulus Parameterization (CP) schemes, while second and third set of experiments is carried out to check the sensitivity of different PBL and Microphysics Parameterization (MP) schemes. The fourth set contains initial condition sensitivity experiments. For first three sets of experiments, 0000 UTC 17 May 2010 is used as initial condition. In CP sensitivity experiments, the track and intensity is well simulated by Betts-Miller-Janjic (BMJ) schemes. The track and intensity of LAILA is very sensitive to the representation of large scale environmental flow in CP scheme as well as to the initial vertical wind shear values. The intensity of the cyclone is well simulated by YSU scheme and it depends upon the mixing treatment in and above PBL. Concentration of frozen hydrometeors, such as graupel in WSM6 MP scheme and latent heat released during auto conversion of hydrometeors may be responsible for storm intensity. An additional set of experiments with different initial vortex intensity shows that, small differences in the initial wind fields have profound impact on both track and intensity of the cyclone. The representation of the mid-tropospheric heating in WSM6 is mainly controlled by amount of graupel hydrometeor and thus might be one of the possible causes in modulating the storm's intensity.
17. Parameterized reduced order models from a single mesh using hyper-dual numbers
Brake, M. R. W.; Fike, J. A.; Topping, S. D.
2016-06-01
In order to assess the predicted performance of a manufactured system, analysts must consider random variations (both geometric and material) in the development of a model, instead of a single deterministic model of an idealized geometry with idealized material properties. The incorporation of random geometric variations, however, potentially could necessitate the development of thousands of nearly identical solid geometries that must be meshed and separately analyzed, which would require an impractical number of man-hours to complete. This research advances a recent approach to uncertainty quantification by developing parameterized reduced order models. These parameterizations are based upon Taylor series expansions of the system's matrices about the ideal geometry, and a component mode synthesis representation for each linear substructure is used to form an efficient basis with which to study the system. The numerical derivatives required for the Taylor series expansions are obtained via hyper-dual numbers, and are compared to parameterized models constructed with finite difference formulations. The advantage of using hyper-dual numbers is two-fold: accuracy of the derivatives to machine precision, and the need to only generate a single mesh of the system of interest. The theory is applied to a stepped beam system in order to demonstrate proof of concept. The results demonstrate that the hyper-dual number multivariate parameterization of geometric variations, which largely are neglected in the literature, are accurate for both sensitivity and optimization studies. As model and mesh generation can constitute the greatest expense of time in analyzing a system, the foundation to create a parameterized reduced order model based off of a single mesh is expected to reduce dramatically the necessary time to analyze multiple realizations of a component's possible geometry.
18. Influence of ground scattering on satellite auroral observations.
PubMed
Hays, P B; Anger, C D
1978-06-15
Satellite observations of the optical emission features in the aurora and nighttime airglow are usually contaminated by scattering from clouds and snow. It is shown here that this contamination can easily be removed when the emission layer is viewed against a surface of known albedo. The effect of the earth's curvature, parallax, and varying image angle are found to be significant but can be removed from the observation.
19. Influence of ground scattering on satellite auroral observations
NASA Technical Reports Server (NTRS)
Hays, P. B.; Anger, C. D.
1978-01-01
Satellite observations of the optical emission features in the aurora and nighttime airglow are usually contaminated by scattering from clouds and snow. It is shown here that this contamination can easily be removed when the emission layer is viewed against a surface of known albedo. The effect of the earth's curvature, parallax, and varying image angle are found to be significant but can be removed from the observation.
20. Migration of scattered teleseismic body waves
Bostock, M. G.; Rondenay, S.
1999-06-01
The retrieval of near-receiver mantle structure from scattered waves associated with teleseismic P and S and recorded on three-component, linear seismic arrays is considered in the context of inverse scattering theory. A Ray + Born formulation is proposed which admits linearization of the forward problem and economy in the computation of the elastic wave Green's function. The high-frequency approximation further simplifies the problem by enabling (1) the use of an earth-flattened, 1-D reference model, (2) a reduction in computations to 2-D through the assumption of 2.5-D experimental geometry, and (3) band-diagonalization of the Hessian matrix in the inverse formulation. The final expressions are in a form reminiscent of the classical diffraction stack of seismic migration. Implementation of this procedure demands an accurate estimate of the scattered wave contribution to the impulse response, and thus requires the removal of both the reference wavefield and the source time signature from the raw record sections. An approximate separation of direct and scattered waves is achieved through application of the inverse free-surface transfer operator to individual station records and a Karhunen-Loeve transform to the resulting record sections. This procedure takes the full displacement field to a wave vector space wherein the first principal component of the incident wave-type section is identified with the direct wave and is used as an estimate of the source time function. The scattered displacement field is reconstituted from the remaining principal components using the forward free-surface transfer operator, and may be reduced to a scattering impulse response upon deconvolution of the source estimate. An example employing pseudo-spectral synthetic seismograms demonstrates an application of the methodology.
1. Laser light scattering review
Schaetzel, Klaus
1989-08-01
Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.
2. Laser light scattering review
NASA Technical Reports Server (NTRS)
Schaetzel, Klaus
1989-01-01
Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.
3. Fiber optic probe for light scattering measurements
DOEpatents
Nave, Stanley E.; Livingston, Ronald R.; Prather, William S.
1995-01-01
A fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman-scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures. The first spectrum is subtracted from the second to remove background effects, and the resulting sample Raman spectrum is compared to a set of stored library spectra to determine the presence and concentration of the analyte.
4. Light Scattering on the High Temperature Superconductors
Slakey, Francis
The high temperature superconductors have been examined by the technique of Raman scattering in several limits: the insulating phase, the normal and superconducting state of the superconducting phase, and an optically induced metastable phase. In all cases, the analysis and proposed phenomenological models involved either an examination of the inelastic background scattering or the phonon excitation spectrum. Specifically, the character, temperature dependence, critical temperature dependence and the copper-oxygen covalency dependence of the inelastic background scattering has been studied in all three phases. Analysis of the superconducting phase reveals a marginal Fermi-liquid like character of the electronic polarizability, and a decidedly non-traditional shift of the scattering intensity of the electronic excitations at low temperature. On removing oxygen, the system passes through a metal-insulator transition and the inelastic background becomes dominantly magnetic in origin. Examinations of the 'allowed' Raman active phonons in the superconducting phase expose a strong coupling of two modes to the background electronic excitation spectrum, and a dramatic renormalization of these modes below T _{rm c}. Further, two sharply resonant Raman 'forbidden' modes can be bleached out of the spectrum at low temperature with a sufficiently high laser dosage. A transition from this optically induced metastable state to the normal state occurs on warming the crystal back to room temperature. On reducing the oxygen concentration, the coupling strength of the two asymmetric phonons diminishes rapidly, the renormalization effects vanish, and the compound no longer exhibits metastability.
5. Fiber optic probe for light scattering measurements
DOEpatents
Nave, S.E.; Livingston, R.R.; Prather, W.S.
1993-01-01
This invention is comprised of a fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman- scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures. The first spectrum is subtracted from the second to remove background effects, and the resulting sample Raman spectrum is compared to a set of stored library spectra to determine the presence and concentration of the analyte.
6. Ground-based remote sensing of aerosol climatology in China: Aerosol optical properties, direct radiative effect and its parameterization
Xia, X.; Che, H.; Zhu, J.; Chen, H.; Cong, Z.; Deng, X.; Fan, X.; Fu, Y.; Goloub, P.; Jiang, H.; Liu, Q.; Mai, B.; Wang, P.; Wu, Y.; Zhang, J.; Zhang, R.; Zhang, X.
2016-01-01
Spatio-temporal variation of aerosol optical properties and aerosol direct radiative effects (ADRE) are studied based on high quality aerosol data at 21 sunphotometer stations with at least 4-months worth of measurements in China mainland and Hong Kong. A parameterization is proposed to describe the relationship of ADREs to aerosol optical depth at 550 nm (AOD) and single scattering albedo at 550 nm (SSA). In the middle-east and south China, the maximum AOD is always observed in the burning season, indicating a significant contribution of biomass burning to AOD. Dust aerosols contribute to AOD significantly in spring and their influence decreases from the source regions to the downwind regions. The occurrence frequencies of background level AOD (AOD < 0.10) in the middle-east, south and northwest China are very limited (0.4%, 1.3% and 2.8%, respectively). However, it is 15.7% in north China. Atmosphere is pristine in the Tibetan Plateau where 92.0% of AODs are <0.10. Regional mean SSAs at 550 nm are 0.89-0.90, although SSAs show substantial site and season dependence. ADREs at the top and bottom of the atmosphere for solar zenith angle of 60 ± 5° are -16--37 W m-2 and -66--111 W m-2, respectively. ADRE efficiency shows slight regional dependence. AOD and SSA together account for more than 94 and 87% of ADRE variability at the bottom and top of the atmosphere. The overall picture of ADRE in China is that aerosols cool the climate system, reduce surface solar radiation and heat the atmosphere.
7. A new parameterization for ice cloud optical properties used in BCC-RAD and its radiative impact
Zhang, Hua; Chen, Qi; Xie, Bing
2015-01-01
8. Phenol removal pretreatment process
DOEpatents
Hames, Bonnie R.
2004-04-13
A process for removing phenols from an aqueous solution is provided, which comprises the steps of contacting a mixture comprising the solution and a metal oxide, forming a phenol metal oxide complex, and removing the complex from the mixture.
9. Turbomachinery debris remover
DOEpatents
Krawiec, Donald F.; Kraf, Robert J.; Houser, Robert J.
1988-01-01
An apparatus for removing debris from a turbomachine. The apparatus includes housing and remotely operable viewing and grappling mechanisms for the purpose of locating and removing debris lodged between adjacent blades in a turbomachine.
10. Wart remover poisoning
MedlinePlus
... Remover Panscol Paplex Ultra PediaPatch Sal-Acid Sal-Plant Salacid Salactic Film Trans-Plantar Trans-Ver-Sal ... you to do so. Flush the eyes with water and remove any medicine that remains on the ...
11. Exploring Mechanisms of Biofilm Removal
PubMed Central
Sahni, Karan; Khashai, Fatemeh; Forghany, Ali; Krasieva, Tatiana; Wilder-Smith, Petra
2016-01-01
exposed to air/water spray alone showed some disruption of the biofilm, leaving residual patches of biofilm that varied considerably in size. Test agent dip treatment followed by air/water spray broke up the continuous layer of biofilm leaving only very small, thin scattered islands of biofilm. Finally, the dynamic test agent spray followed by air/water spray removed the biofilm almost entirely, with evidence of only very few small, thin residual biofilm islands. Conclusion These studies demonstrate that test agent desiccant effect alone causes some disruption of dental biofilm. Additional dynamic rinsing is needed to achieve complete removal of dental biofilm. PMID:27413588
12. Electromagnetic scattering theory
NASA Technical Reports Server (NTRS)
Bird, J. F.; Farrell, R. A.
1986-01-01
Electromagnetic scattering theory is discussed with emphasis on the general stochastic variational principle (SVP) and its applications. The stochastic version of the Schwinger-type variational principle is presented, and explicit expressions for its integrals are considered. Results are summarized for scalar wave scattering from a classic rough-surface model and for vector wave scattering from a random dielectric-body model. Also considered are the selection of trial functions and the variational improvement of the Kirchhoff short-wave approximation appropriate to large size-parameters. Other applications of vector field theory discussed include a general vision theory and the analysis of hydromagnetism induced by ocean motion across the geomagnetic field. Levitational force-torque in the magnetic suspension of the disturbance compensation system (DISCOS), now deployed in NOVA satellites, is also analyzed using the developed theory.
13. MAGNETIC NEUTRON SCATTERING
SciTech Connect
ZALIZNYAK,I.A.; LEE,S.H.
2004-07-30
Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern science
14. Interstellar Dust Scattering Properties
Gordon, K. D.
2004-05-01
Studies of dust scattering properties in astrophysical objects with Milky Way interstellar dust are reviewed. Such objects are reflection nebulae, dark clouds, and the Diffuse Galactic Light (DGL). To ensure their basic quality, studies had to satisfy four basic criteria to be included in this review. These four criteria significantly reduced the scatter in dust properties measurements, especially in the case of the DGL. Determinations of dust scattering properties were found to be internally consistent for each object type as well as consistent between object types. The 2175 Å bump is seen as an absorption feature. Comparisons with dust grain models find general agreement with significant disagreements at particular wavelengths (especially in the far-ultraviolet). Finally, unanswered questions and future directions are enumerated.
15. Dynamic Scattering Mode LCDs
The following sections are included: * INTRODUCTION * CELL DESIGNING * EXPERIMENTAL OBSERVATIONS IN NEMATICS RELATED WITH DYNAMIC SCATTERING * Experimental Observations at D.C. Field and Electrode Effects * Experimental Observation at Low Frequency A.C. Fields * Homogeneously Aligned Nematic Regime * Williams Domains * Dynamic Scattering * Experimental Observation at High Frequency A.C. Field * Other Experimental Observations * THEORETICAL INTERPRETATIONS * Felici Model * Carr-Helfrich Model * D.C. Excitation * Dubois-Violette, de Gennes and Parodi Model * Low Freqency or Conductive Regime * High Frequency or Dielectric Regime * DYNAMIC SCATTERING IN SMECRIC A PHASE * ELECTRO-OPTICAL CHARACTERISTICS AND LIMITATIONS * Contrast Ratio vs. Voltage, Viewing Angle, Cell Gap, Wavelength and Temperature * Display Current vs. Voltage, Cell Gap and Temperature * Switching Time * Effect of Alignment * Effect of Conductivity, Temperature and Frequency * Addressing of DSM LCDs * Limitations of DSM LCDs * ACKNOWLEDGEMENTS * REFERENCES
16. Scattering Of Light Nuclei
SciTech Connect
Quaglioni, S; Navratil, P; Roth, R
2009-12-15
The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.
17. Impact of model structure and parameterization on Penman-Monteith type evaporation models
Ershadi, A.; McCabe, M. F.; Evans, J. P.; Wood, E. F.
2015-06-01
The impact of model structure and parameterization on the estimation of evaporation is investigated across a range of Penman-Monteith type models. To examine the role of model structure on flux retrievals, three different retrieval schemes are compared. The schemes include a traditional single-source Penman-Monteith model (Monteith, 1965), a two-layer model based on Shuttleworth and Wallace (1985) and a three-source model based on Mu et al. (2011). To assess the impact of parameterization choice on model performance, a number of commonly used formulations for aerodynamic and surface resistances were substituted into the different formulations. Model response to these changes was evaluated against data from twenty globally distributed FLUXNET towers, representing a cross-section of biomes that include grassland, cropland, shrubland, evergreen needleleaf forest and deciduous broadleaf forest. Scenarios based on 14 different combinations of model structure and parameterization were ranked based on their mean value of Nash-Sutcliffe Efficiency. Results illustrated considerable variability in model performance both within and between biome types. Indeed, no single model consistently outperformed any other when considered across all biomes. For instance, in grassland and shrubland sites, the single-source Penman-Monteith model performed the best. In croplands it was the three-source Mu model, while for evergreen needleleaf and deciduous broadleaf forests, the Shuttleworth-Wallace model rated highest. Interestingly, these top ranked scenarios all shared the simple lookup-table based surface resistance parameterization of Mu et al. (2011), while a more complex Jarvis multiplicative method for surface resistance produced lower ranked simulations. The highly ranked scenarios mostly employed a version of the Thom (1975) formulation for aerodynamic resistance that incorporated dynamic values of roughness parameters. This was true for all cases except over deciduous broadleaf
18. A process-based fire parameterization of intermediate complexity in a Dynamic Global Vegetation Model
Li, F.; Zeng, X. D.; Levis, S.
2012-07-01
A process-based fire parameterization of intermediate complexity has been developed for global simulations in the framework of a Dynamic Global Vegetation Model (DGVM) in an Earth System Model (ESM). Burned area in a grid cell is estimated by the product of fire counts and average burned area of a fire. The scheme comprises three parts: fire occurrence, fire spread, and fire impact. In the fire occurrence part, fire counts rather than fire occurrence probability are calculated in order to capture the observed high burned area fraction in areas of high fire frequency and realize parameter calibration based on MODIS fire counts product. In the fire spread part, post-fire region of a fire is assumed to be elliptical in shape. Mathematical properties of ellipses and some mathematical derivations are applied to improve the equation and assumptions of an existing fire spread parameterization. In the fire impact part, trace gas and aerosol emissions due to biomass burning are estimated, which offers an interface with atmospheric chemistry and aerosol models in ESMs. In addition, flexible time-step length makes the new fire parameterization easily applied to various DGVMs. Global performance of the new fire parameterization is assessed by using an improved version of the Community Land Model version 3 with the Dynamic Global Vegetation Model (CLM-DGVM). Simulations are compared against the latest satellite-based Global Fire Emission Database version 3 (GFED3) for 1997-2004. Results show that simulated global totals and spatial patterns of burned area and fire carbon emissions, regional totals and spreads of burned area, global annual burned area fractions for various vegetation types, and interannual variability of burned area are reasonable, and closer to GFED3 than CLM-DGVM simulations with the commonly used Glob-FIRM fire parameterization and the old fire module of CLM-DGVM. Furthermore, average error of simulated trace gas and aerosol emissions due to biomass burning
19. A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli
DOE PAGES
Berg, L. K.; Shrivastava, M.; Easter, R. C.; Fast, J. D.; Chapman, E. G.; Liu, Y.; Ferrare, R. A.
2015-02-24
A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convectivemore » cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain–Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud–aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as –50% when cloud–aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it
20. A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli
SciTech Connect
Berg, L. K.; Shrivastava, M.; Easter, R. C.; Fast, J. D.; Chapman, E. G.; Liu, Y.; Ferrare, R. A.
2015-02-24
A new treatment of cloud effects on aerosol and trace gases within parameterized shallow and deep convection, and aerosol effects on cloud droplet number, has been implemented in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) version 3.2.1 that can be used to better understand the aerosol life cycle over regional to synoptic scales. The modifications to the model include treatment of the cloud droplet number mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. These changes have been implemented in both the WRF-Chem chemistry packages as well as the Kain–Fritsch (KF) cumulus parameterization that has been modified to better represent shallow convective clouds. Testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS). The simulation results are used to investigate the impact of cloud–aerosol interactions on regional-scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column-integrated BC can be as large as –50% when cloud–aerosol interactions are considered (due largely to wet removal), or as large as +40% for sulfate under non-precipitating conditions due to sulfate production in the parameterized clouds. The modifications to WRF-Chem are found to account for changes in the cloud droplet number concentration (CDNC) and changes in the chemical composition of cloud droplet residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to the latest version of WRF-Chem, and it is
1. Spatially resolved scattering polarimeter.
PubMed
Kohlgraf-Owens, Thomas; Dogariu, Aristide
2009-05-01
We demonstrate a compact, spatially resolved polarimeter based on a coherent optical fiber bundle coupled with a thin layer of scattering centers. The use of scattering for polarization encoding allows the polarimeter to work across broad angular and spectral domains. Optical fiber bundles provide high spatial resolution of the incident field. Because neighboring elements of the bundle interact with the incident field differently, only a single interaction of the fiber bundle with the unknown field is needed to perform the measurement. Experimental results are shown to demonstrate the capability to perform imaging polarimetry. PMID:19412259
2. FINAL REPORT (DE-FG02-97ER62338): Single-column modeling, GCM parameterizations, and ARM data
SciTech Connect
Richard C. J. Somerville
2009-02-27
Our overall goal is the development of new and improved parameterizations of cloud-radiation effects and related processes, using ARM data at all three ARM sites, and the implementation and testing of these parameterizations in global models. To test recently developed prognostic parameterizations based on detailed cloud microphysics, we have compared SCM (single-column model) output with ARM observations at the SGP, NSA and TWP sites. We focus on the predicted cloud amounts and on a suite of radiative quantities strongly dependent on clouds, such as downwelling surface shortwave radiation. Our results demonstrate the superiority of parameterizations based on comprehensive treatments of cloud microphysics and cloud-radiative interactions. At the SGP and NSA sites, the SCM results simulate the ARM measurements well and are demonstrably more realistic than typical parameterizations found in conventional operational forecasting models. At the TWP site, the model performance depends strongly on details of the scheme, and the results of our diagnostic tests suggest ways to develop improved parameterizations better suited to simulating cloud-radiation interactions in the tropics generally. These advances have made it possible to take the next step and build on this progress, by incorporating our parameterization schemes in state-of-the-art three-dimensional atmospheric models, and diagnosing and evaluating the results using independent data. Because the improved cloud-radiation results have been obtained largely via implementing detailed and physically comprehensive cloud microphysics, we anticipate that improved predictions of hydrologic cycle components, and hence of precipitation, may also be achievable.
3. Development and Testing of Coupled Land-surface, PBL and Shallow/Deep Convective Parameterizations within the MM5
NASA Technical Reports Server (NTRS)
Stauffer, David R.; Seaman, Nelson L.; Munoz, Ricardo C.
2000-01-01
The objective of this investigation was to study the role of shallow convection on the regional water cycle of the Mississippi and Little Washita Basins using a 3-D mesoscale model, the PSUINCAR MM5. The underlying premise of the project was that current modeling of regional-scale climate and moisture cycles over the continents is deficient without adequate treatment of shallow convection. It was hypothesized that an improved treatment of the regional water cycle can be achieved by using a 3-D mesoscale numerical model having a detailed land-surface parameterization, an advanced boundary-layer parameterization, and a more complete shallow convection parameterization than are available in most current models. The methodology was based on the application in the MM5 of new or recently improved parameterizations covering these three physical processes. Therefore, the work plan focused on integrating, improving, and testing these parameterizations in the MM5 and applying them to study water-cycle processes over the Southern Great Plains (SGP): (1) the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) described by Wetzel and Boone; (2) the 1.5-order turbulent kinetic energy (TKE)-predicting scheme of Shafran et al.; and (3) the hybrid-closure sub-grid shallow convection parameterization of Deng. Each of these schemes has been tested extensively through this study and the latter two have been improved significantly to extend their capabilities.
4. Atom scattering from metals
Hayes, W. W.
In the initial portion of this dissertation studies of Ar scattering from Ru(0001) at thermal and hyperthermal energies are compared to calculations with classical scattering theory. These data exhibited a number of characteristics that are unusual in comparison to other systems for which atomic beam experiments have been carried out under similar conditions. The measured energy losses were unusually small. Some of the angular distributions exhibited an anomalous shoulder feature in addition to a broad peak near the specular direction and quantum mechanical diffraction was observed under conditions for which it was not expected. Many of the unusual features observed in the measurements are explained, but only upon using an effective surface mass of 2.3 Ru atomic masses, which implies collective effects in the Ru crystal. The large effective mass, because it leads to substantially larger Debye-Waller factors, explains and confirms the observations of diffraction features. It also leads to the interesting conclusion that Ru is a metal for which atomic beam scattering measurements in the purely quantum mechanical regime, where diffraction and single-phonon creation are dominant, should be possible not only with He atoms, but with many other atomic species with larger masses. A useful theoretical expression for interpreting and analyzing observed scattering intensity spectra for atomic and molecular collisions with surfaces is the differential reflection coefficient for a smooth, vibrating surface. This differential reflection coefficient depends on a parameter, usually expressed in dimensions of velocity, that arises due to correlated motions of neighboring regions of the surface and can be evaluated if the polarization vectors of the phonons near the surface are known. As a part of this dissertation experimental conditions are suggested under which this velocity paramenter may be more precisely measured than it has been in the past. Experimental data for scattering
5. Graphitic packing removal tool
SciTech Connect
Meyers, K.E.; Kolsun, G.J.
1996-12-31
Graphitic packing removal tools are described for removal of the seal rings in one piece from valves and pumps. The packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal.
6. Graphitic packing removal tool
DOEpatents
Meyers, K.E.; Kolsun, G.J.
1997-11-11
Graphitic packing removal tools for removal of the seal rings in one piece are disclosed. The packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal. 5 figs.
7. Graphitic packing removal tool
DOEpatents
Meyers, Kurt Edward; Kolsun, George J.
1997-01-01
Graphitic packing removal tools for removal of the seal rings in one piece. he packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal.
8. Fast engineering optimization: A novel highly effective control parameterization approach for industrial dynamic processes.
PubMed
Liu, Ping; Li, Guodong; Liu, Xinggao
2015-09-01
Control vector parameterization (CVP) is an important approach of the engineering optimization for the industrial dynamic processes. However, its major defect, the low optimization efficiency caused by calculating the relevant differential equations in the generated nonlinear programming (NLP) problem repeatedly, limits its wide application in the engineering optimization for the industrial dynamic processes. A novel highly effective control parameterization approach, fast-CVP, is first proposed to improve the optimization efficiency for industrial dynamic processes, where the costate gradient formulae is employed and a fast approximate scheme is presented to solve the differential equations in dynamic process simulation. Three well-known engineering optimization benchmark problems of the industrial dynamic processes are demonstrated as illustration. The research results show that the proposed fast approach achieves a fine performance that at least 90% of the computation time can be saved in contrast to the traditional CVP method, which reveals the effectiveness of the proposed fast engineering optimization approach for the industrial dynamic processes.
9. Application of Stochastic Radiative Transfer Theory to the ARM Cloud-Radiative Parameterization Problem
SciTech Connect
Veron, Dana E
2009-03-12
This project had two primary goals: 1) development of stochastic radiative transfer as a parameterization that could be employed in an AGCM environment, and 2) exploration of the stochastic approach as a means for representing shortwave radiative transfer through mixed-phase layer clouds. To achieve these goals, an analysis of the performance of the stochastic approach was performed, a simple stochastic cloud-radiation parameterization for an AGCM was developed and tested, a statistical description of Arctic mixed phase clouds was developed and the appropriateness of stochastic approach for representing radiative transfer through mixed-phase clouds was assessed. Significant progress has been made in all of these areas and is detailed below.
10. Application of Stochastic Radiative Transfer Theory to the ARM Cloud-Radiative Parameterization Problem
SciTech Connect
Dana E. Veron
2012-04-09
This project had two primary goals: (1) development of stochastic radiative transfer as a parameterization that could be employed in an AGCM environment, and (2) exploration of the stochastic approach as a means for representing shortwave radiative transfer through mixed-phase layer clouds. To achieve these goals, climatology of cloud properties was developed at the ARM CART sites, an analysis of the performance of the stochastic approach was performed, a simple stochastic cloud-radiation parameterization for an AGCM was developed and tested, a statistical description of Arctic mixed phase clouds was developed and the appropriateness of stochastic approach for representing radiative transfer through mixed-phase clouds was assessed. Significant progress has been made in all of these areas and is detailed in the final report.
11. Application of a semi-spectral cloud water parameterization to cooling tower plumes simulations
Bouzereau, Emmanuel; Musson Genon, Luc; Carissimo, Bertrand
2008-10-01
In order to simulate the plume produced by large natural draft cooling towers, a semi-spectral warm cloud parameterization has been implemented in an anelastic and non-hydrostatic 3D micro-scale meteorological code. The model results are compared to observations from a detailed field experiment carried out in 1980 at Bugey (location of an electrical nuclear power plant in the Rhône valley in East Central France) including airborne dynamical and microphysical measurements. Although we observe a slight overestimation of the liquid-water content, the results are satisfactory for all the 15 different cases simulated, which include different meteorological conditions ranging from low wind speed and convective conditions in clear sky to high wind and very cloudy. Such parameterization, which includes semi-spectral determination for droplet spectra, seems to be promising to describe plume interaction with atmosphere especially for aerosols and cloud droplets.
12. The interpretation of remotely sensed cloud properties from a model parameterization perspective
SciTech Connect
1995-09-01
The goals of ISCCP and FIRE are, broadly speaking, to provide methods for the retrieval of cloud properties from satellites, and to improve cloud radiation models and the parameterization of clouds in GCMs. This study suggests a direction for GCM cloud parameterizations based on analysis of Landsat and ISCCP satellite data. For low level single layer clouds it is found that the mean retrieved liquid water pathe in cloudy pixels is essentially invariant to the cloud fraction, at least in the range 0.2 - 0.8. This result is very important since it allows the cloud fraction to be estimated if the mean liquid water path of cloud in a general circulation model gridcell is known. 3 figs.
13. The meridional variation of the eddy heat fluxes by baroclinic waves and their parameterization
NASA Technical Reports Server (NTRS)
Stone, P. H.
1974-01-01
The meridional and vertical eddy fluxes of sensible heat produced by small-amplitude growing baroclinic waves are calculated using solutions to the two-level model with horizontal shear in the mean flow. The results show that the fluxes are primarily dependent on the local baroclinicity, i.e., the local value of the isentropic slopes in the mean state. Where the slope exceeds the critical value, the transports are poleward and upward; where the slope is less than the critical value, the transports are equatorward and downward. These results are used to improve an earlier parameterization of the tropospheric eddy fluxes of sensible heat based on Eady's model. Comparisons with observations show that the improved parameterization reproduces the observed magnitude and sign of the eddy fluxes and their vertical variations and seasonal changes, but the maximum in the poleward flux is too near the equator.
14. Evaluating and Understanding Parameterized Convective Processes and their Role in the Development of Mesoscale Precipitation Systems
NASA Technical Reports Server (NTRS)
Fritsch, J. Michael; Kain, John S.
1997-01-01
Research efforts during the second year have centered on improving the manner in which convective stabilization is achieved in the Penn State/NCAR mesoscale model MM5. Ways of improving this stabilization have been investigated by (1) refining the partitioning between the Kain-Fritsch convective parameterization scheme and the grid scale by introducing a form of moist convective adjustment; (2) using radar data to define locations of subgrid-scale convection during a dynamic initialization period; and (3) parameterizing deep-convective feedbacks as subgrid-scale sources and sinks of mass. These investigations were conducted by simulating a long-lived convectively-generated mesoscale vortex that occurred during 14-18 Jul. 1982 and the 10-11 Jun. 1985 squall line that occurred over the Kansas-Oklahoma region during the PRE-STORM experiment. The long-lived vortex tracked across the central Plains states and was responsible for multiple convective outbreaks during its lifetime.
15. Application of a planetary wave breaking parameterization to stratospheric circulation statistics
NASA Technical Reports Server (NTRS)
Randel, William J.; Garcia, Rolando R.
1994-01-01
The planetary wave parameterization scheme developed recently by Garcia is applied to statospheric circulation statistics derived from 12 years of National Meteorological Center operational stratospheric analyses. From the data a planetary wave breaking criterion (based on the ratio of the eddy to zonal mean meridional potential vorticity (PV) gradients), a wave damping rate, and a meridional diffusion coefficient are calculated. The equatorward flank of the polar night jet during winter is identified as a wave breaking region from the observed PV gradients; the region moves poleward with season, covering all high latitudes in spring. Derived damping rates maximize in the subtropical upper stratosphere (the 'surf zone'), with damping time scales of 3-4 days. Maximum diffusion coefficients follow the spatial patterns of the wave breaking criterion, with magnitudes comparable to prior published estimates. Overall, the observed results agree well with the parameterized calculations of Garcia.
16. A cumulus parameterization scheme designed for nested grid meso-{beta} scale models
SciTech Connect
Weissbluth, M.J.; Cotton, W.R.
1991-12-31
A generalized cumulus parameterization based upon higher order turbulence closure has been incorporated into one dimensional simulations. The scheme consists of a level 2.5w turbulence closure scheme mated with a convective adjustment scheme. The convective adjustment scheme includes a gradient term which can be interpreted as either a subsidence term when the scheme is used in large scale models or a mesoscale compensation term when the scheme is used in mesoscale models. The scheme also includes a convective adjustment term which is interpreted as a detrainment term in large scale models. In mesoscale models, the mesoscale compensation term and the advection by the mean vertical motions combine to yield no net advection which is desirable since the convective moistening and heating is now wholly accomplished by the convective adjustment term; double counting is then explicitly eliminated. One dimensional simulations indicate satisfactory performance of the cumulus parameterization scheme for a non-entraining updraft.
17. A cumulus parameterization scheme designed for nested grid meso-. beta. scale models
SciTech Connect
Weissbluth, M.J.; Cotton, W.R.
1991-01-01
A generalized cumulus parameterization based upon higher order turbulence closure has been incorporated into one dimensional simulations. The scheme consists of a level 2.5w turbulence closure scheme mated with a convective adjustment scheme. The convective adjustment scheme includes a gradient term which can be interpreted as either a subsidence term when the scheme is used in large scale models or a mesoscale compensation term when the scheme is used in mesoscale models. The scheme also includes a convective adjustment term which is interpreted as a detrainment term in large scale models. In mesoscale models, the mesoscale compensation term and the advection by the mean vertical motions combine to yield no net advection which is desirable since the convective moistening and heating is now wholly accomplished by the convective adjustment term; double counting is then explicitly eliminated. One dimensional simulations indicate satisfactory performance of the cumulus parameterization scheme for a non-entraining updraft.
18. Mesoscale model parameterizations for radiation and turbulent fluxes at the lower boundary
Somieski, Franz
1988-11-01
A radiation parameterization scheme for use in mesoscale models with orography and clouds was developed. Broadband parameterizations are presented for the solar and the terrestrial spectral ranges. They account for clear, turbid, or cloudy atmospheres. The scheme is one-dimensional in the atmosphere, but the effects of mountains (inclination, shading, elevated horizon) are taken into account at the surface. In the terrestrial brand, gray and black clouds are considered. The calculation of turbulent fluxes of sensible and latent heat and momentum at an inclined lower model boundary is described. Surface-layer similarity and the surface energy budget are used to evaluate the ground surface temperature. The total scheme is part of the mesoscale model MESOSCOP.
19. Lidar observations of mixed layer dynamics - Tests of parameterized entrainment models of mixed layer growth rate
NASA Technical Reports Server (NTRS)
Boers, R.; Eloranta, E. W.; Coulter, R. L.
1984-01-01
Ground based lidar measurements of the atmospheric mixed layer depth, the entrainment zone depth and the wind speed and wind direction were used to test various parameterized entrainment models of mixed layer growth rate. Six case studies under clear air convective conditions over flat terrain in central Illinois are presented. It is shown that surface heating alone accounts for a major portion of the rise of the mixed layer on all days. A new set of entrainment model constants was determined which optimized height predictions for the dataset. Under convective conditions, the shape of the mixed layer height prediction curves closely resembled the observed shapes. Under conditions when significant wind shear was present, the shape of the height prediction curve departed from the data suggesting deficiencies in the parameterization of shear production. Development of small cumulus clouds on top of the layer is shown to affect mixed layer depths in the afternoon growth phase.
20. Study of NWP parameterizations on extreme precipitation events over Basque Country
Gelpi, Iván R.; Gaztelumendi, Santiago; Carreño, Sheila; Hernández, Roberto; Egaña, Joseba
2016-08-01
The Weather Research and Forecasting model (WRF), like other numerical models, can make use of several parameterization schemes. The purpose of this study is to determine how available cumulus parameterization (CP) and microphysics (MP) schemes in the WRF model simulate extreme precipitation events in the Basque Country. Possible combinations among two CP schemes (Kain-Fritsch and Betts-Miller-Janjic) and five MP (WSM3, Lin, WSM6, new Thompson and WDM6) schemes were tested. A set of simulations, corresponding to 21st century extreme precipitation events that have caused significant flood episodes have been compared with point observational data coming from the Basque Country Automatic Weather Station Mesonetwork. Configurations with Kain-Fritsch CP scheme produce better quantity of precipitation forecast (QPF) than BMJ scheme configurations. Depending on the severity level and the river basin analysed different MP schemes show the best behaviours, demonstrating that there is not a unique configuration that solve exactly all the studied events.
1. Fluorescence and Light Scattering
ERIC Educational Resources Information Center
Clarke, Ronald J.; Oprysa, Anna
2004-01-01
The aim of the mentioned experiment is to aid students in developing tactics for distinguishing between signals originating from fluorescence and light scattering. Also, the experiment provides students with a deeper understanding of the physicochemical bases of each phenomenon and shows that the techniques are actually related.
2. Nanowire electron scattering spectroscopy
NASA Technical Reports Server (NTRS)
Hunt, Brian D. (Inventor); Bronikowski, Michael (Inventor); Wong, Eric W. (Inventor); von Allmen, Paul (Inventor); Oyafuso, Fabiano A. (Inventor)
2009-01-01
Methods and devices for spectroscopic identification of molecules using nanoscale wires are disclosed. According to one of the methods, nanoscale wires are provided, electrons are injected into the nanoscale wire; and inelastic electron scattering is measured via excitation of low-lying vibrational energy levels of molecules bound to the nanoscale wire.
3. Critical fluid light scattering
NASA Technical Reports Server (NTRS)
Gammon, Robert W.
1988-01-01
The objective is to measure the decay rates of critical density fluctuations in a simple fluid (xenon) very near its liquid-vapor critical point using laser light scattering and photon correlation spectroscopy. Such experiments were severely limited on Earth by the presence of gravity which causes large density gradients in the sample when the compressibility diverges approaching the critical point. The goal is to measure fluctuation decay rates at least two decades closer to the critical point than is possible on earth, with a resolution of 3 microK. This will require loading the sample to 0.1 percent of the critical density and taking data as close as 100 microK to the critical temperature. The minimum mission time of 100 hours will allow a complete range of temperature points to be covered, limited by the thermal response of the sample. Other technical problems have to be addressed such as multiple scattering and the effect of wetting layers. The experiment entails measurement of the scattering intensity fluctuation decay rate at two angles for each temperature and simultaneously recording the scattering intensities and sample turbidity (from the transmission). The analyzed intensity and turbidity data gives the correlation length at each temperature and locates the critical temperature. The fluctuation decay rate data from these measurements will provide a severe test of the generalized hydrodynamic theories of transport coefficients in the critical regions. When compared to equivalent data from binary liquid critical mixtures they will test the universality of critical dynamics.
4. Inelastic Scattering Form Factors
1992-01-01
ATHENA-IV computes form factors for inelastic scattering calculations, using single-particle wave functions that are eigenstates of motion in either a Woods-Saxon potential well or a harmonic oscillator well. Two-body forces of Gauss, Coulomb, Yukawa, and a sum of cut-off Yukawa radial dependences are available.
5. Elastic scattering using an artificial confining potential.
PubMed
Mitroy, J; Zhang, J Y; Varga, K
2008-09-19
The discrete energies of a scattering Hamiltonian calculated under the influence of an artificial confining potential of almost arbitrary functional form can be used to determine its phase shifts. The method exploits the result that two short-range Hamiltonians having the same energy will have the same phase shifts upon removal of the confining potential. An initial verification is performed on a simple model problem. Then the stochastic variational method is used to determine the energies of the confined e(-)-He(2)S(e) system and thus determine the low energy phase shifts.
6. Parameterizing the Transport Pathways for Cell Invasion in Complex Scaffold Architectures
PubMed Central
Ashworth, Jennifer C.; Mehr, Marco; Buxton, Paul G.; Best, Serena M.
2016-01-01
Interconnecting pathways through porous tissue engineering scaffolds play a vital role in determining nutrient supply, cell invasion, and tissue ingrowth. However, the global use of the term “interconnectivity” often fails to describe the transport characteristics of these pathways, giving no clear indication of their potential to support tissue synthesis. This article uses new experimental data to provide a critical analysis of reported methods for the description of scaffold transport pathways, ranging from qualitative image analysis to thorough structural parameterization using X-ray Micro-Computed Tomography. In the collagen scaffolds tested in this study, it was found that the proportion of pore space perceived to be accessible dramatically changed depending on the chosen method of analysis. Measurements of % interconnectivity as defined in this manner varied as a function of direction and connection size, and also showed a dependence on measurement length scale. As an alternative, a method for transport pathway parameterization was investigated, using percolation theory to calculate the diameter of the largest sphere that can travel to infinite distance through a scaffold in a specified direction. As proof of principle, this approach was used to investigate the invasion behavior of primary fibroblasts in response to independent changes in pore wall alignment and pore space accessibility, parameterized using the percolation diameter. The result was that both properties played a distinct role in determining fibroblast invasion efficiency. This example therefore demonstrates the potential of the percolation diameter as a method of transport pathway parameterization, to provide key structural criteria for application-based scaffold design. PMID:26888449
7. Land surface hydrology parameterization for atmospheric general circulation models including subgrid scale spatial variability
NASA Technical Reports Server (NTRS)
Entekhabi, D.; Eagleson, P. S.
1989-01-01
Parameterizations are developed for the representation of subgrid hydrologic processes in atmospheric general circulation models. Reasonable a priori probability density functions of the spatial variability of soil moisture and of precipitation are introduced. These are used in conjunction with the deterministic equations describing basic soil moisture physics to derive expressions for the hydrologic processes that include subgrid scale variation in parameters. The major model sensitivities to soil type and to climatic forcing are explored.
8. Approaches to highly parameterized inversion-A guide to using PEST for groundwater-model calibration
USGS Publications Warehouse
Doherty, John E.; Hunt, Randall J.
2010-01-01
Highly parameterized groundwater models can create calibration difficulties. Regularized inversion-the combined use of large numbers of parameters with mathematical approaches for stable parameter estimation-is becoming a common approach to address these difficulties and enhance the transfer of information contained in field measurements to parameters used to model that system. Though commonly used in other industries, regularized inversion is somewhat imperfectly understood in the groundwater field. There is concern that this unfamiliarity can lead to underuse, and misuse, of the methodology. This document is constructed to facilitate the appropriate use of regularized inversion for calibrating highly parameterized groundwater models. The presentation is directed at an intermediate- to advanced-level modeler, and it focuses on the PEST software suite-a frequently used tool for highly parameterized model calibration and one that is widely supported by commercial graphical user interfaces. A brief overview of the regularized inversion approach is provided, and techniques for mathematical regularization offered by PEST are outlined, including Tikhonov, subspace, and hybrid schemes. Guidelines for applying regularized inversion techniques are presented after a logical progression of steps for building suitable PEST input. The discussion starts with use of pilot points as a parameterization device and processing/grouping observations to form multicomponent objective functions. A description of potential parameter solution methodologies and resources available through the PEST software and its supporting utility programs follows. Directing the parameter-estimation process through PEST control variables is then discussed, including guidance for monitoring and optimizing the performance of PEST. Comprehensive listings of PEST control variables, and of the roles performed by PEST utility support programs, are presented in the appendixes.
9. Parameterization of biogeochemical sediment-water fluxes using in situ measurements and a diagenetic model
Laurent, A.; Fennel, K.; Wilson, R.; Lehrter, J.; Devereux, R.
2016-01-01
Diagenetic processes are important drivers of water column biogeochemistry in coastal areas. For example, sediment oxygen consumption can be a significant contributor to oxygen depletion in hypoxic systems, and sediment-water nutrient fluxes support primary productivity in the overlying water column. Moreover, nonlinearities develop between bottom water conditions and sediment-water fluxes due to loss of oxygen-dependent processes in the sediment as oxygen becomes depleted in bottom waters. Yet, sediment-water fluxes of chemical species are often parameterized crudely in coupled physical-biogeochemical models, using simple linear parameterizations that are only poorly constrained by observations. Diagenetic models that represent sediment biogeochemistry are available, but rarely are coupled to water column biogeochemical models because they are computationally expensive. Here, we apply a method that efficiently parameterizes sediment-water fluxes of oxygen, nitrate and ammonium by combining in situ measurements, a diagenetic model and a parameter optimization method. As a proof of concept, we apply this method to the Louisiana Shelf where high primary production, stimulated by excessive nutrient loads from the Mississippi-Atchafalaya River system, promotes the development of hypoxic bottom waters in summer. The parameterized sediment-water fluxes represent nonlinear feedbacks between water column and sediment processes at low bottom water oxygen concentrations, which may persist for long periods (weeks to months) in hypoxic systems such as the Louisiana Shelf. This method can be applied to other systems and is particularly relevant for shallow coastal and estuarine waters where the interaction between sediment and water column is strong and hypoxia is prone to occur due to land-based nutrient loads.
10. Parameterizing correlations between hydrometeor species in mixed-phase Arctic clouds
Larson, Vincent E.; Nielsen, Brandon J.; Fan, Jiwen; Ovchinnikov, Mikhail
2011-01-01
Mixed-phase Arctic clouds, like other clouds, contain small-scale variability in hydrometeor fields, such as cloud water or snow mixing ratio. This variability may be worth parameterizing in coarse-resolution numerical models. In particular, for modeling multispecies processes such as accretion and aggregation, it would be useful to parameterize subgrid correlations among hydrometeor species. However, one difficulty is that there exist many hydrometeor species and many microphysical processes, leading to complexity and computational expense. Existing lower and upper bounds on linear correlation coefficients are too loose to serve directly as a method to predict subgrid correlations. Therefore, this paper proposes an alternative method that begins with the spherical parameterization framework of Pinheiro and Bates (1996), which expresses the correlation matrix in terms of its Cholesky factorization. The values of the elements of the Cholesky matrix are populated here using a "cSigma" parameterization that we introduce based on the aforementioned bounds on correlations. The method has three advantages: (1) the computational expense is tolerable; (2) the correlations are, by construction, guaranteed to be consistent with each other; and (3) the methodology is fairly general and hence may be applicable to other problems. The method is tested noninteractively using simulations of three Arctic mixed-phase cloud cases from two field experiments: the Indirect and Semi-Direct Aerosol Campaign and the Mixed-Phase Arctic Cloud Experiment. Benchmark simulations are performed using a large-eddy simulation (LES) model that includes a bin microphysical scheme. The correlations estimated by the new method satisfactorily approximate the correlations produced by the LES.
11. A parameterization of respiration in frozen soils based on substrate availability
Schaefer, Kevin; Jafarov, Elchin
2016-04-01
Respiration in frozen soils is limited to thawed substrate within the thin water films surrounding soil particles. As temperatures decrease and the films become thinner, the available substrate also decreases, with respiration effectively ceasing at -8 °C. Traditional exponential scaling factors to model this effect do not account for substrate availability and do not work at the century to millennial timescales required to model the fate of the nearly 1100 Gt of carbon in permafrost regions. The exponential scaling factor produces a false, continuous loss of simulated permafrost carbon in the 20th century and biases in estimates of potential emissions as permafrost thaws in the future. Here we describe a new frozen biogeochemistry parameterization that separates the simulated carbon into frozen and thawed pools to represent the effects of substrate availability. We parameterized the liquid water fraction as a function of temperature based on observations and use this to transfer carbon between frozen pools and thawed carbon in the thin water films. The simulated volumetric water content (VWC) as a function of temperature is consistent with observed values and the simulated respiration fluxes as a function of temperature are consistent with results from incubation experiments. The amount of organic matter was the single largest influence on simulated VWC and respiration fluxes. Future versions of the parameterization should account for additional, non-linear effects of substrate diffusion in thin water films on simulated respiration. Controlling respiration in frozen soils based on substrate availability allows us to maintain a realistic permafrost carbon pool by eliminating the continuous loss caused by the original exponential scaling factors. The frozen biogeochemistry parameterization is a useful way to represent the effects of substrate availability on soil respiration in model applications that focus on century to millennial timescales in permafrost regions.
12. Subgrid-scale physical parameterization in atmospheric modeling: How can we make it consistent?
Yano, Jun-Ichi
2016-07-01
Approaches to subgrid-scale physical parameterization in atmospheric modeling are reviewed by taking turbulent combustion flow research as a point of reference. Three major general approaches are considered for its consistent development: moment, distribution density function (DDF), and mode decomposition. The moment expansion is a standard method for describing the subgrid-scale turbulent flows both in geophysics and engineering. The DDF (commonly called PDF) approach is intuitively appealing as it deals with a distribution of variables in subgrid scale in a more direct manner. Mode decomposition was originally applied by Aubry et al (1988 J. Fluid Mech. 192 115-73) in the context of wall boundary-layer turbulence. It is specifically designed to represent coherencies in compact manner by a low-dimensional dynamical system. Their original proposal adopts the proper orthogonal decomposition (empirical orthogonal functions) as their mode-decomposition basis. However, the methodology can easily be generalized into any decomposition basis. Among those, wavelet is a particularly attractive alternative. The mass-flux formulation that is currently adopted in the majority of atmospheric models for parameterizing convection can also be considered a special case of mode decomposition, adopting segmentally constant modes for the expansion basis. This perspective further identifies a very basic but also general geometrical constraint imposed on the massflux formulation: the segmentally-constant approximation. Mode decomposition can, furthermore, be understood by analogy with a Galerkin method in numerically modeling. This analogy suggests that the subgrid parameterization may be re-interpreted as a type of mesh-refinement in numerical modeling. A link between the subgrid parameterization and downscaling problems is also pointed out.
13. Global Simulations from CAM with a Unified Convection Parameterization using CLUBB and Subcolumns
Thayer-Calder, K.; Gettelman, A.; Craig, C.; Goldhaber, S.; Bogenschutz, P.; Chen, C. C.; Morrison, H.; Hoft, J.; Raut, E.; Griffin, B. M.; Weber, J. K.; Larson, V. E.; Wyant, M. C.; Wang, M.; Ghan, S.; Guo, Z.
2015-12-01
The newest version of the Community Atmosphere Model (CAM) will support subcolumns as a method to better couple sub-grid-scale convective and microphysical processes. We utilize this feature and samples from a PDF-based moist turbulence parameterization to produce a version of CAM where all convection (shallow, stratiform, and deep) is simulated with a single set of dynamic and microphysical equations. We call this version of the model CAM-CLUBB-SILHS, where CLUBB (Cloud Layers Unified By Binormals) is our higher-order closure convection and turbulence parameterization and SILHS (Subgrid Importance Latin Hypercube Sampler) is our sampler and the basis for our subcolumn generation. Each physics timestep in this model, the CLUBB parameterization runs to calculate convective tendencies. In order to close the higher order moments, CLUBB calculates a new multi-variate PDF describing the subgrid distribution of moisture and temperature at each level. SILHS samples from that PDF and creates profiles of vapor, temperature, vertical velocity, cloud water and ice, and cloud water and ice number concentration. The microphysics scheme runs on each subcolumn seperately. The resulting tendencies are averaged together and returned to the model as a grid mean tendency. This use of subcolumns allows us to explicitly represent subgrid scale clouds and moisture distributions for microphysical calculations. Using this framework and no other convective parameterizations, we are able to produce stable, realistic, global atmospheric simulations in CAM. This study will present results from long-term atmospheric simulations, discuss the impact of subcolumns on the model, and show improvements in the model's tropical wave simulation.
14. Limitations of one-dimensional mesoscale PBL parameterizations in reproducing mountain-wave flows
SciTech Connect
Munoz-Esparza, Domingo; Sauer, Jeremy A.; Linn, Rodman R.; Kosovic, Branko
2015-12-08
In this study, mesoscale models are considered to be the state of the art in modeling mountain-wave flows. Herein, we investigate the role and accuracy of planetary boundary layer (PBL) parameterizations in handling the interaction between large-scale mountain waves and the atmospheric boundary layer. To that end, we use recent large-eddy simulation (LES) results of mountain waves over a symmetric two-dimensional bell-shaped hill [Sauer et al., J. Atmos. Sci. (2015)], and compare them to four commonly used PBL schemes. We find that one-dimensional PBL parameterizations produce reasonable agreement with the LES results in terms of vertical wavelength, amplitude of velocity and turbulent kinetic energy distribution in the downhill shooting flow region. However, the assumption of horizontal homogeneity in PBL parameterizations does not hold in the context of these complex flow configurations. This inappropriate modeling assumption results in a vertical wavelength shift producing errors of ≈ 10 m s–1 at downstream locations due to the presence of a coherent trapped lee wave that does not mix with the atmospheric boundary layer. In contrast, horizontally-integrated momentum flux derived from these PBL schemes displays a realistic pattern. Therefore results from mesoscale models using ensembles of one-dimensional PBL schemes can still potentially be used to parameterize drag effects in general circulation models. Nonetheless, three-dimensional PBL schemes must be developed in order for mesoscale models to accurately represent complex-terrain and other types of flows where one-dimensional PBL assumptions are violated.
15. Limitations of one-dimensional mesoscale PBL parameterizations in reproducing mountain-wave flows
DOE PAGES
Munoz-Esparza, Domingo; Sauer, Jeremy A.; Linn, Rodman R.; Kosovic, Branko
2015-12-08
In this study, mesoscale models are considered to be the state of the art in modeling mountain-wave flows. Herein, we investigate the role and accuracy of planetary boundary layer (PBL) parameterizations in handling the interaction between large-scale mountain waves and the atmospheric boundary layer. To that end, we use recent large-eddy simulation (LES) results of mountain waves over a symmetric two-dimensional bell-shaped hill [Sauer et al., J. Atmos. Sci. (2015)], and compare them to four commonly used PBL schemes. We find that one-dimensional PBL parameterizations produce reasonable agreement with the LES results in terms of vertical wavelength, amplitude of velocitymore » and turbulent kinetic energy distribution in the downhill shooting flow region. However, the assumption of horizontal homogeneity in PBL parameterizations does not hold in the context of these complex flow configurations. This inappropriate modeling assumption results in a vertical wavelength shift producing errors of ≈ 10 m s–1 at downstream locations due to the presence of a coherent trapped lee wave that does not mix with the atmospheric boundary layer. In contrast, horizontally-integrated momentum flux derived from these PBL schemes displays a realistic pattern. Therefore results from mesoscale models using ensembles of one-dimensional PBL schemes can still potentially be used to parameterize drag effects in general circulation models. Nonetheless, three-dimensional PBL schemes must be developed in order for mesoscale models to accurately represent complex-terrain and other types of flows where one-dimensional PBL assumptions are violated.« less
16. Sensitivity of Tropical Cyclones to Parameterized Convection in the NASA GEOS5 Model
NASA Technical Reports Server (NTRS)
Lim, Young-Kwon; Schubert, Siegfried D.; Reale, Oreste; Lee, Myong-In; Molod, Andrea M.; Suarez, Max J.
2014-01-01
The sensitivity of tropical cyclones (TCs) to changes in parameterized convection is investigated to improve the simulation of TCs in the North Atlantic. Specifically, the impact of reducing the influence of the Relaxed Arakawa-Schubert (RAS) scheme-based parameterized convection is explored using the Goddard Earth Observing System version5 (GEOS5) model at 0.25 horizontal resolution. The years 2005 and 2006 characterized by very active and inactive hurricane seasons, respectively, are selected for simulation. A reduction in parameterized deep convection results in an increase in TC activity (e.g., TC number and longer life cycle) to more realistic levels compared to the baseline control configuration. The vertical and horizontal structure of the strongest simulated hurricane shows the maximum lower-level (850-950hPa) wind speed greater than 60 ms and the minimum sea level pressure reaching 940mb, corresponding to a category 4 hurricane - a category never achieved by the control configuration. The radius of the maximum wind of 50km, the location of the warm core exceeding 10 C, and the horizontal compactness of the hurricane center are all quite realistic without any negatively affecting the atmospheric mean state. This study reveals that an increase in the threshold of minimum entrainment suppresses parameterized deep convection by entraining more dry air into the typical plume. This leads to cooling and drying at the mid- to upper-troposphere, along with the positive latent heat flux and moistening in the lower-troposphere. The resulting increase in conditional instability provides an environment that is more conducive to TC vortex development and upward moisture flux convergence by dynamically resolved moist convection, thereby increasing TC activity.
17. Impact of Parameterized Lee Wave Drag on the Energy Budget of an Eddying Global Ocean Model
Trossman, D. S.; Arbic, B. K.; Garner, S.; Goff, J. A.; Jayne, S. R.; Metzger, E.; Wallcraft, A.
2012-12-01
We examine the impact of a lee wave drag parameterization on an eddying global ocean model. The wave drag parameterization represents the the momentum transfer associated with the generation of lee waves arising from geostrophic flow impinging upon rough topography. It is included in the online model, thus ensuring that abyssal currents and stratification in the simulation are affected by the presence of the wave drag. The model utilized here is the nominally 1/12th degree Hybrid Coordinate Ocean Model (HYCOM) forced by winds and air-sea buoyancy fluxes. An energy budget including the parameterized wave drag, quadratic bottom boundary layer drag, vertical eddy viscosity, and horizontal eddy viscosity is diagnosed during the model runs and compared with the wind power input and buoyancy fluxes. Wave drag and vertical viscosity are the largest of the mechanical energy dissipation rate terms, each more than half of a terawatt when globally integrated. The sum of all four dissipative terms approximately balances the rate of energy put by the winds and buoyancy fluxes into the ocean. An ad hoc global enhancement of the bottom drag at each grid point by a constant factor cannot serve as a perfect substitute for wave drag, particularly where there is little wave drag. Eddy length scales at the surface, sea surface height variance, surface kinetic energy, and positions of intensified jets in the model are compared with those inferred from altimetric observations. Vertical profiles of kinetic energy from the model are compared with mooring observations to investigate whether the model is improved when wave drag is inserted.; The drag and viscosity terms in our energy budget [log_10(W m^-2)]: (a) quadratic bottom boundary layer drag, (b) parameterized internal lee wave drag, (c) vertical viscosity, and (d) "horizontal" viscosity. Shown is an average of inline estimates over one year of the spin-up phase with wave drag.
18. Large eddy simulation for evaluating scale-aware subgrid cloud parameterizations
Huang, Wei; Chen, Baode; Bao, Jian-Wen
2016-04-01
We present results from an ongoing project that uses a Large-Eddy Simulation (LES) model to simulate deep organized convection in the extratropics for the purpose of evaluating scale-aware subgrid convective parameterizations. The simulation is carried out for a classical idealized supercell thunderstorm (Weisman and Klemp, 1982), using a total of 1201 × 1201 × 200 grid points at 100 m spacing in both the horizontal and vertical directions. The characteristics of simulated clouds exhibit a multi-mode vertical distribution ranging from deep to shallow clouds, which is similar to that observed in the real world. To use the LES dataset for evaluating scale-aware subgrid cloud parameterizations, the same case is also run with progressively larger grid sizes of 200 m, 400 m, 600 m, 1 km and 3 km. These simulations show a reasonable agreement with the benchmark LES in statistics such as convective available potential energy, convective inhibition, cloud fraction and precipitation rates. They provide useful information about the effect of horizontal grid resolution on the subgrid convective parameterizations. All these simulations reveal a similar multi-mode cloud distribution in the vertical direction. However, there are differences in the updraft-core cloud statistics, and convergence of statistical properties is found only between the LES benchmark and the simulation with grid size smaller than 400 m. Analysis of the LES results indicates that (1) the average subgrid mass flux increases as the horizontal grid size increases; (2) the vertical scale of subgrid transport varies spatially, suggesting a system dependence; and (3) at even 1 km, sub-grid convective transport is still large enough to be accounted for through parameterization.
19. Parameterizing correlations between hydrometeor species in mixed-phase Arctic clouds
SciTech Connect
Larson, Vincent E.; Nielsen, Brandon J.; Fan, Jiwen; Ovchinnikov, Mikhail
2011-08-16
Mixed-phase Arctic clouds, like other clouds, contain small-scale variability in hydrometeor fields, such as cloud water or snow mixing ratio. This variability may be worth parameterizing in coarse-resolution numerical models. In particular, for modeling processes such as accretion and aggregation, it would be useful to parameterize subgrid correlations among hydrometeor species. However, one difficulty is that there exist many hydrometeor species and many microphysical processes, leading to complexity and computational expense.Existing lower and upper bounds (inequalities) on linear correlation coefficients provide useful guidance, but these bounds are too loose to serve directly as a method to predict subgrid correlations. Therefore, this paper proposes an alternative method that is based on a blend of theory and empiricism. The method begins with the spherical parameterization framework of Pinheiro and Bates (1996), which expresses the correlation matrix in terms of its Cholesky factorization. The values of the elements of the Cholesky matrix are parameterized here using a cosine row-wise formula that is inspired by the aforementioned bounds on correlations. The method has three advantages: 1) the computational expense is tolerable; 2) the correlations are, by construction, guaranteed to be consistent with each other; and 3) the methodology is fairly general and hence may be applicable to other problems. The method is tested non-interactively using simulations of three Arctic mixed-phase cloud cases from two different field experiments: the Indirect and Semi-Direct Aerosol Campaign (ISDAC) and the Mixed-Phase Arctic Cloud Experiment (M-PACE). Benchmark simulations are performed using a large-eddy simulation (LES) model that includes a bin microphysical scheme. The correlations estimated by the new method satisfactorily approximate the correlations produced by the LES.
20. An efficient physically based parameterization to derive surface solar irradiance based on satellite atmospheric products
Qin, Jun; Tang, Wenjun; Yang, Kun; Lu, Ning; Niu, Xiaolei; Liang, Shunlin
2015-05-01
Surface solar irradiance (SSI) is required in a wide range of scientific researches and practical applications. Many parameterization schemes are developed to estimate it using routinely measured meteorological variables, since SSI is directly measured at a very limited number of stations. Even so, meteorological stations are still sparse, especially in remote areas. Remote sensing can be used to map spatiotemporally continuous SSI. Considering the huge amount of satellite data, coarse-resolution SSI has been estimated for reducing the computational burden when the estimation is based on a complex radiative transfer model. On the other hand, many empirical relationships are used to enhance the retrieval efficiency, but the accuracy cannot be guaranteed out of regions where they are locally calibrated. In this study, an efficient physically based parameterization is proposed to balance computational efficiency and retrieval accuracy for SSI estimation. In this parameterization, the transmittances for gases, aerosols, and clouds are all handled in full band form and the multiple reflections between the atmosphere and surface are explicitly taken into account. The newly proposed parameterization is applied to estimate SSI with both Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric and land products as inputs. These retrievals are validated against in situ measurements at the Surface Radiation Budget Network and at the North China Plain on an instantaneous basis, and moreover, they are validated and compared with Global Energy and Water Exchanges-Surface Radiation Budget and International Satellite Cloud Climatology Project-flux data SSI estimates at radiation stations of China Meteorological Administration on a daily mean basis. The estimation results indicates that the newly proposed SSI estimation scheme can effectively retrieve SSI based on MODIS products with mean root-mean-square errors of about 100 Wm- 1 and 35 Wm- 1 on an instantaneous and daily
1. Modeling late rectal toxicities based on a parameterized representation of the 3D dose distribution
Buettner, Florian; Gulliford, Sarah L.; Webb, Steve; Partridge, Mike
2011-04-01
Many models exist for predicting toxicities based on dose-volume histograms (DVHs) or dose-surface histograms (DSHs). This approach has several drawbacks as firstly the reduction of the dose distribution to a histogram results in the loss of spatial information and secondly the bins of the histograms are highly correlated with each other. Furthermore, some of the complex nonlinear models proposed in the past lack a direct physical interpretation and the ability to predict probabilities rather than binary outcomes. We propose a parameterized representation of the 3D distribution of the dose to the rectal wall which explicitly includes geometrical information in the form of the eccentricity of the dose distribution as well as its lateral and longitudinal extent. We use a nonlinear kernel-based probabilistic model to predict late rectal toxicity based on the parameterized dose distribution and assessed its predictive power using data from the MRC RT01 trial (ISCTRN 47772397). The endpoints under consideration were rectal bleeding, loose stools, and a global toxicity score. We extract simple rules identifying 3D dose patterns related to a specifically low risk of complication. Normal tissue complication probability (NTCP) models based on parameterized representations of geometrical and volumetric measures resulted in areas under the curve (AUCs) of 0.66, 0.63 and 0.67 for predicting rectal bleeding, loose stools and global toxicity, respectively. In comparison, NTCP models based on standard DVHs performed worse and resulted in AUCs of 0.59 for all three endpoints. In conclusion, we have presented low-dimensional, interpretable and nonlinear NTCP models based on the parameterized representation of the dose to the rectal wall. These models had a higher predictive power than models based on standard DVHs and their low dimensionality allowed for the identification of 3D dose patterns related to a low risk of complication.
2. Parameterization of the stomatal component of the DO3SE model for Mediterranean evergreen broadleaf species.
PubMed
Alonso, Rocío; Elvira, Susana; Sanz, María J; Emberson, Lisa; Gimeno, Benjamín S
2007-01-01
An ozone (O3) deposition model (DO3SE) is currently used in Europe to define the areas where O3 concentrations lead to absorbed O3 doses that exceed the flux-based critical levels above which phytotoxic effects would be likely recorded. This mapping exercise relies mostly on the accurate estimation of O3 flux through plant stomata. However, the present parameterization of the modulation of stomatal conductance (g(s)) behavior by different environmental variables needs further adjustment if O3 phytotoxicity is to be assessed accurately at regional or continental scales. A new parameterization of the model is proposed for Holm oak (Quercus ilex), a tree species that has been selected as a surrogate for all Mediterranean evergreen broadleaf species. This parameterization was based on a literature review, and was calibrated and validated using experimentally measured data of g(s) and several atmospheric and soil parameters recorded at three sites of the Iberian Peninsula experiencing long summer drought, and very cold and dry winter air (El Pardo and Miraflores) or milder conditions (Tietar). A fairly good agreement was found between modeled and measured data (R2 = 0.64) at Tietar. However, a reasonable performance (R2 = 0.47-0.62) of the model was only achieved at the most continental sites when g(s) and soil moisture deficit relationships were considered. The influence of root depth on g(s) estimation is discussed and recommendations are made to build up separate parameterizations for continental and marine-influenced Holm oak sites in the future.
3. Amplification of intrinsic emittance due to rough metal cathodes: Formulation of a parameterization model
Charles, T. K.; Paganin, D. M.; Dowd, R. T.
2016-08-01
Intrinsic emittance is often the limiting factor for brightness in fourth generation light sources and as such, a good understanding of the factors affecting intrinsic emittance is essential in order to be able to decrease it. Here we present a parameterization model describing the proportional increase in emittance induced by cathode surface roughness. One major benefit behind the parameterization approach presented here is that it takes the complexity of a Monte Carlo model and reduces the results to a straight-forward empirical model. The resulting models describe the proportional increase in transverse momentum introduced by surface roughness, and are applicable to various metal types, photon wavelengths, applied electric fields, and cathode surface terrains. The analysis includes the increase in emittance due to changes in the electric field induced by roughness as well as the increase in transverse momentum resultant from the spatially varying surface normal. We also compare the results of the Parameterization Model to an Analytical Model which employs various approximations to produce a more compact expression with the cost of a reduction in accuracy.
4. Comparison and validation of physical wave parameterizations in spectral wave models
Stopa, Justin E.; Ardhuin, Fabrice; Babanin, Alexander; Zieger, Stefan
2016-07-01
Recent developments in the physical parameterizations available in spectral wave models have already been validated, but there is little information on their relative performance especially with focus on the higher order spectral moments and wave partitions. This study concentrates on documenting their strengths and limitations using satellite measurements, buoy spectra, and a comparison between the different models. It is confirmed that all models perform well in terms of significant wave heights; however higher-order moments have larger errors. The partition wave quantities perform well in terms of direction and frequency but the magnitude and directional spread typically have larger discrepancies. The high-frequency tail is examined through the mean square slope using satellites and buoys. From this analysis it is clear that some models behave better than the others, suggesting their parameterizations match the physical processes reasonably well. However none of the models are entirely satisfactory, pointing to poorly constrained parameterizations or missing physical processes. The major space-time differences between the models are related to the swell field which stresses the importance of describing its evolution. An example swell field confirms the wave heights can be notably different between model configurations while the directional distributions remain similar. It is clear that all models have difficulty describing the directional spread. Therefore, knowledge of the source term directional distributions is paramount to improve the wave model physics in the future.
5. Parameterized data-driven fuzzy model based optimal control of a semi-batch reactor.
PubMed
Kamesh, Reddi; Rani, K Yamuna
2016-09-01
A parameterized data-driven fuzzy (PDDF) model structure is proposed for semi-batch processes, and its application for optimal control is illustrated. The orthonormally parameterized input trajectories, initial states and process parameters are the inputs to the model, which predicts the output trajectories in terms of Fourier coefficients. Fuzzy rules are formulated based on the signs of a linear data-driven model, while the defuzzification step incorporates a linear regression model to shift the domain from input to output domain. The fuzzy model is employed to formulate an optimal control problem for single rate as well as multi-rate systems. Simulation study on a multivariable semi-batch reactor system reveals that the proposed PDDF modeling approach is capable of capturing the nonlinear and time-varying behavior inherent in the semi-batch system fairly accurately, and the results of operating trajectory optimization using the proposed model are found to be comparable to the results obtained using the exact first principles model, and are also found to be comparable to or better than parameterized data-driven artificial neural network model based optimization results.
6. Intrinsic parameterization of a computational optical system for long-distance displacement structural monitoring
Martins, Luís F. Lages; Rebordão, José Manuel N. V.; Ribeiro, Álvaro Silva
2015-01-01
We aim at the intrinsic parameterization of a computational optical system applied in long-distance displacement measurement of large-scale structures. In this structural-monitoring scenario, the observation distance established between the digital camera and reference targets, which is composed of the computational optical system, can range from 100 up to 1000 m, requiring the use of long-focal length lenses in order to obtain a suitable sensitivity for the three-dimensional displacement measurement of the observed structure which can be of reduced magnitude. Intrinsic parameterization of long-focal length cameras is an emergent issue since conventional approaches applied for reduced focal length cameras are not suitable mainly due to ill-conditioned matrices in least squares estimation procedures. We describe the intrinsic parameterization of a long-focal length camera (600 mm) by the diffractive optical element method and present the obtained estimates and measurement uncertainties, discussing their contribution for the system's validation by calibration field test and displacement measurement campaigns in a long-span suspension bridge.
7. Intercomparison of Martian Lower Atmosphere Simulated Using Different Planetary Boundary Layer Parameterization Schemes
NASA Technical Reports Server (NTRS)
Natarajan, Murali; Fairlie, T. Duncan; Dwyer Cianciolo, Alicia; Smith, Michael D.
2015-01-01
We use the mesoscale modeling capability of Mars Weather Research and Forecasting (MarsWRF) model to study the sensitivity of the simulated Martian lower atmosphere to differences in the parameterization of the planetary boundary layer (PBL). Characterization of the Martian atmosphere and realistic representation of processes such as mixing of tracers like dust depend on how well the model reproduces the evolution of the PBL structure. MarsWRF is based on the NCAR WRF model and it retains some of the PBL schemes available in the earth version. Published studies have examined the performance of different PBL schemes in NCAR WRF with the help of observations. Currently such assessments are not feasible for Martian atmospheric models due to lack of observations. It is of interest though to study the sensitivity of the model to PBL parameterization. Typically, for standard Martian atmospheric simulations, we have used the Medium Range Forecast (MRF) PBL scheme, which considers a correction term to the vertical gradients to incorporate nonlocal effects. For this study, we have also used two other parameterizations, a non-local closure scheme called Yonsei University (YSU) PBL scheme and a turbulent kinetic energy closure scheme called Mellor- Yamada-Janjic (MYJ) PBL scheme. We will present intercomparisons of the near surface temperature profiles, boundary layer heights, and wind obtained from the different simulations. We plan to use available temperature observations from Mini TES instrument onboard the rovers Spirit and Opportunity in evaluating the model results.
8. Improving Parameterization of Entrainment Rate for Shallow Convection with Aircraft Measurements and Large-Eddy Simulation
DOE PAGES
Lu, Chunsong; Liu, Yangang; Zhang, Guang J.; Wu, Xianghua; Endo, Satoshi; Cao, Le; Li, Yueqing; Guo, Xiaohao
2016-02-01
This work examines the relationships of entrainment rate to vertical velocity, buoyancy, and turbulent dissipation rate by applying stepwise principal component regression to observational data from shallow cumulus clouds collected during the Routine AAF [Atmospheric Radiation Measurement (ARM) Aerial Facility] Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) field campaign over the ARM Southern Great Plains (SGP) site near Lamont, Oklahoma. The cumulus clouds during the RACORO campaign simulated using a large eddy simulation (LES) model are also examined with the same approach. The analysis shows that a combination of multiple variables can better represent entrainment ratemore » in both the observations and LES than any single-variable fitting. Three commonly used parameterizations are also tested on the individual cloud scale. A new parameterization is therefore presented that relates entrainment rate to vertical velocity, buoyancy and dissipation rate; the effects of treating clouds as ensembles and humid shells surrounding cumulus clouds on the new parameterization are discussed. Physical mechanisms underlying the relationships of entrainment rate to vertical velocity, buoyancy and dissipation rate are also explored.« less
9. Optimized conformal parameterization of cortical surfaces using shape based matching of landmark curves.
PubMed
2008-01-01
In this work, we find meaningful parameterizations of cortical surfaces utilizing prior anatomical information in the form of anatomical landmarks (sulci curves) on the surfaces. Specifically we generate close to conformal parametrizations that also give a shape-based correspondence between the landmark curves. We propose a variational energy that measures the harmonic energy of the parameterization maps, and the shape dissimilarity between mapped points on the landmark curves. The novelty is that the computed maps are guaranteed to give a shape-based diffeomorphism between the landmark curves. We achieve this by intrinsically modelling our search space of maps as flows of smooth vector fields that do not flow across the landmark curves, and by using the local surface geometry on the curves to define a shape measure. Such parameterizations ensure consistent correspondence between anatomical features, ensuring correct averaging and comparison of data across subjects. The utility of our model is demonstrated in experiments on cortical surfaces with landmarks delineated, which show that our computed maps give a shape-based alignment of the sulcal curves without significantly impairing conformality. PMID:18979783
10. Constructing the Coronal Magnetic Field: by Correlating Parameterized Magnetic Field Lines with Observed Coronal Plasma Structures
NASA Technical Reports Server (NTRS)
Gary, G. A.
1998-01-01
The reconstruction of the coronal magnetic field is carried out using a perturbation procedure. A set of magnetic field lines generated from magnetogram data is parameterized and then deformed by varying the parameterized values. The coronal fluxtubes associated with this field are adjusted until the correlation between the field lines and the observed coronal loops is maximized. A mathematical formulation is described which ensures (1) that the normal component of the photospheric field remains unchanged, (2) that the field is given in the entire corona, (3) that the field remains divergence free, and (4) that electrical currents are introduced into the field. It is demonstrated that a simple radial parameterization of a potential field, comprising a radial stretching of the field, can provide a match for a simple bipolar active region, AR 7999, which crossed the central meridian on 1996 Nov 26. At a coronal height of 30 km, the resulting magnetic field is a non-force free magnetic field with the maximum Lorentz force being on the order of 2.6 x 10(exp -9) dyn resulting from an electric current density of \$0.13 mu A/ sq m. This scheme is an important tool in generating a magnetic field solution consistent with the coronal flux tube observations and the observed photospheric magnetic field.
11. Refinement, Validation and Application of Cloud-Radiation Parameterization in a GCM
SciTech Connect
Dr. Graeme L. Stephens
2009-04-30
The research performed under this award was conducted along 3 related fronts: (1) Refinement and assessment of parameterizations of sub-grid scale radiative transport in GCMs. (2) Diagnostic studies that use ARM observations of clouds and convection in an effort to understand the effects of moist convection on its environment, including how convection influences clouds and radiation. This aspect focuses on developing and testing methodologies designed to use ARM data more effectively for use in atmospheric models, both at the cloud resolving model scale and the global climate model scale. (3) Use (1) and (2) in combination with both models and observations of varying complexity to study key radiation feedback Our work toward these objectives thus involved three corresponding efforts. First, novel diagnostic techniques were developed and applied to ARM observations to understand and characterize the effects of moist convection on the dynamical and thermodynamical environment in which it occurs. Second, an in house GCM radiative transfer algorithm (BUGSrad) was employed along with an optimal estimation cloud retrieval algorithm to evaluate the ability to reproduce cloudy-sky radiative flux observations. Assessments using a range of GCMs with various moist convective parameterizations to evaluate the fidelity with which the parameterizations reproduce key observable features of the environment were also started in the final year of this award. The third study area involved the study of cloud radiation feedbacks and we examined these in both cloud resolving and global climate models.
12. Size-resolved parameterization of primary organic carbon in fresh marine aerosols
SciTech Connect
Long, Michael S; Keene, William C; Erickson III, David J
2009-12-01
Marine aerosols produced by the bursting of artificially generated bubbles in natural seawater are highly enriched (2 to 3 orders of magnitude based on bulk composition) in marine-derived organic carbon (OC). Production of size-resolved particulate OC was parameterized based on a Langmuir kinetics-type association of OC to bubble plumes in seawater and resulting aerosol as constrained by measurements of aerosol produced from highly productive and oligotrophic seawater. This novel approach is the first to account for the influence of adsorption on the size-resolved association between marine aerosols and OC. Production fluxes were simulated globally with an eight aerosol-size-bin version of the NCAR Community Atmosphere Model (CAM v3.5.07). Simulated number and inorganic sea-salt mass production fell within the range of published estimates based on observationally constrained parameterizations. Because the parameterization does not consider contributions from spume drops, the simulated global mass flux (1.5 x 10{sup 3} Tg y{sup -1}) is near the lower limit of published estimates. The simulated production of aerosol number (2.1 x 10{sup 6} cm{sup -2} s{sup -1}) and OC (49 Tg C y{sup -1}) fall near the upper limits of published estimates and suggest that primary marine aerosols may have greater influences on the physiochemical evolution of the troposphere, radiative transfer and climate, and associated feedbacks on the surface ocean than suggested by previous model studies.
13. Analysis and parameterization of the combined coalescence, breakup, and evaporation processes
SciTech Connect
Brown, P.S. Jr.
1993-09-01
A parameterization of raindrop coalescence and breakup has been extended to include evaporation. The parameterization is developed through analysis of accurate numerical solutions of the coalescence/breakup/evaporation equation. Modeled drop size distributions are found to evolve first toward a trimodal form characteristic of the equilibrium distribution that occurs when only collisional processes are at work. With sustained evaporation, the trimodality disappears and a unimodal-type drop size distribution emerges. The results imply that the trimodal form occurs when collisional processes are dominant but that a unimodal distribution prevails as the water mass is reduced. The mass reduction causes collisions to become infrequent and allows evaporation to deplete the small-sized raindrop population. When subjected to continued evaporation, the coalescence/breakup equilibrium itself undergoes a transition from trimodal form, and it is this evolving form toward which all other drop size distributions converge. In the transition, the liquid water content decreases exponentially with a time constant of 300/S s, where S is the saturation deficit; furthermore, the shape of the evaporating distribution is determined by the ratio of liquid water content to the saturation deficit. The parameterization procedure makes use of the analysis results in order to describe system behavior.
14. X-ray scatter correction in breast tomosynthesis with a precomputed scatter map library
PubMed Central
Feng, Steve Si Jia; D’Orsi, Carl J.; Newell, Mary S.; Seidel, Rebecca L.; Patel, Bhavika; Sechopoulos, Ioannis
2014-01-01
Purpose: To develop and evaluate the impact on lesion conspicuity of a software-based x-ray scatter correction algorithm for digital breast tomosynthesis (DBT) imaging into which a precomputed library of x-ray scatter maps is incorporated. Methods: A previously developed model of compressed breast shapes undergoing mammography based on principal component analysis (PCA) was used to assemble 540 simulated breast volumes, of different shapes and sizes, undergoing DBT. A Monte Carlo (MC) simulation was used to generate the cranio-caudal (CC) view DBT x-ray scatter maps of these volumes, which were then assembled into a library. This library was incorporated into a previously developed software-based x-ray scatter correction, and the performance of this improved algorithm was evaluated with an observer study of 40 patient cases previously classified as BI-RADS® 4 or 5, evenly divided between mass and microcalcification cases. Observers were presented with both the original images and the scatter corrected (SC) images side by side and asked to indicate their preference, on a scale from −5 to +5, in terms of lesion conspicuity and quality of diagnostic features. Scores were normalized such that a negative score indicates a preference for the original images, and a positive score indicates a preference for the SC images. Results: The scatter map library removes the time-intensive MC simulation from the application of the scatter correction algorithm. While only one in four observers preferred the SC DBT images as a whole (combined mean score = 0.169 ± 0.37, p > 0.39), all observers exhibited a preference for the SC images when the lesion examined was a mass (1.06 ± 0.45, p < 0.0001). When the lesion examined consisted of microcalcification clusters, the observers exhibited a preference for the uncorrected images (−0.725 ± 0.51, p < 0.009). Conclusions: The incorporation of the x-ray scatter map library into the scatter correction algorithm improves the efficiency
15. Small angle neutron scattering
Cousin, Fabrice
2015-10-01
Small Angle Neutron Scattering (SANS) is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ˜ 1 nm up to ˜ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ˜ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area…) through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons) make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer), form factor analysis (I(q→0), Guinier regime, intermediate regime, Porod regime, polydisperse system), structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates), and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast). It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of spectrometer
16. Rayleigh's Scattering Revised
Kolomiets, Sergey; Gorelik, Andrey
This report is devoted to a discussion of applicability limits of Rayleigh’s scattering model. Implicitly, Rayleigh’s ideas are being used in a wide range of remote sensing applications. To begin with it must be noted that most techniques which have been developed to date for measurements by means of active instruments for remote sensing in case of the target is a set of distributed moving scatters are only hopes, to say so, on measurements per se. The problem is that almost all of such techniques use a priori information about the microstructure of the object of interest during whole measurement session. As one can find in the literature, this approach may happily be applied to systems with identical particles. However, it is not the case with respect to scattering targets that consist of particles of different kind or having a particle size distribution. It must be especially noted that the microstructure of most of such targets changes significantly with time and/or space. Therefore, the true measurement techniques designed to be applicable in such conditions must be not only adaptable in order to take into account a variety of models of an echo interpretation, but also have a well-developed set of clear-cut criteria of applicability and exact means of accuracy estimation. So such techniques will require much more parameters to be measured. In spite of the fact that there is still room for some improvements within classical models and approaches, it is multiwavelength approach that may be seen as the most promising way of development towards obtaining an adequate set of the measured parameters required for true measurement techniques. At the same time, Rayleigh’s scattering is an invariant in regard to a change of the wavelength as it follows from the point of view dominating nowadays. In the light of such an idea, the synergy between multivawelength measurements may be achieved - to a certain extent - by means of the synchronous usage of Rayleigh’s and
17. Integrated Raman and angular scattering of single biological cells
Smith, Zachary J.
2009-12-01
Raman, or inelastic, scattering and angle-resolved elastic scattering are two optical processes that have found wide use in the study of biological systems. Raman scattering quantitatively reports on the chemical composition of a sample by probing molecular vibrations, while elastic scattering reports on the morphology of a sample by detecting structure-induced coherent interference between incident and scattered light. We present the construction of a multimodal microscope platform capable of gathering both elastically and inelastically scattered light from a 38 mum2 region in both epi- and trans-illumination geometries. Simultaneous monitoring of elastic and inelastic scattering from a microscopic region allows noninvasive characterization of a living sample without the need for exogenous dyes or labels. A sample is illuminated either from above or below with a focused 785 nm TEM00 mode laser beam, with elastic and inelastic scattering collected by two separate measurement arms. The measurements may be made either simultaneously, if identical illumination geometries are used, or sequentially, if the two modalities utilize opposing illumination paths. In the inelastic arm, Stokes-shifted light is dispersed by a spectrograph onto a CCD array. In the elastic scattering collection arm, a relay system images the microscope's back aperture onto a CCD detector array to yield an angle-resolved elastic scattering pattern. Post-processing of the inelastic scattering to remove fluorescence signals yields high quality Raman spectra that report on the sample's chemical makeup. Comparison of the elastically scattered pupil images to generalized Lorenz-Mie theory yields estimated size distributions of scatterers within the sample. In this thesis we will present validations of the IRAM instrument through measurements performed on single beads of a few microns in size, as well as on ensembles of sub-micron particles of known size distributions. The benefits and drawbacks of the
18. Angle resolved scatter measurement of bulk scattering in transparent ceramics
Sharma, Saurabh; Miller, J. Keith; Shori, Ramesh K.; Goorsky, Mark S.
2015-02-01
Bulk scattering in polycrystalline laser materials (PLM), due to non-uniform refractive index across the bulk, is regarded as the primary loss mechanism leading to degradation of laser performance with higher threshold and lower output power. The need for characterization techniques towards identifying bulk scatter and assessing the quality. Assessment of optical quality and the identification of bulk scatter have been by simple visual inspection of thin samples of PLMs, thus making the measurements highly subjective and inaccurate. Angle Resolved Scatter (ARS) measurement allows for the spatial mapping of scattered light at all possible angles about a sample, mapping the intensity for both forward scatter and back-scatter regions. The cumulative scattered light intensity, in the forward scatter direction, away from the specular beam is used for the comparison of bulk scattering between samples. This technique employ the detection of scattered light at all angles away from the specular beam directions and represented as a 2-D polar map. The high sensitivity of the ARS technique allows us to compare bulk scattering in different PLM samples which otherwise had similar transmitted beam wavefront distortions.
19. Thermodynamic parameterization
Gorban, Alexander N.; Karlin, Iliya V.
1992-12-01
A new method of succesive construction of a solution is developed for problems of strongly nonequilibrium Boltzmann kinetics beyond normal solutions. Firstly, the method provides dynamic equations for any manifold of distributions where one looks for an approximate solution. Secondly, it gives a successive procedure of obtaining corrections to these approximations. The method requires meither small parameters, nor strong restrictions upon the initial approximation; it involves solutions of linear problems. It is concordant with the H-theorem at every step. In particular, for the Tamm-Mott-Smith approximation, dynamic equations are obtained, an expansion for the strong shock is introduced, and a linear equation for the first correction is found.
20. Parameterization and comparative evaluation of the CCN number concentration on Mt. Huang, China
Fang, Shasha; Han, Yongxiang; Chen, Kui; Lu, Chunsong; Yin, Yan; Tan, Haobo; Wang, Jin
2016-11-01
Quantifying regional CCN concentration is important for reliable estimations of aerosol indirect effects. Based on observational data of the number concentrations of total aerosol (NCN) and cloud condensation nuclei (NCCN), particle number size distribution (PNSD) and, size-resolved activation ratio (SRAR) obtained on Mt. Huang in southeast China from September 19 to October 11, 2012, seven parameterization schemes are used to calculate NCCN employing CCN spectra, bulk activation ratio, cut-off diameter and SRAR. The calculations and the observations are compared and analyzed at four supersaturations (S) from 0.109% to 0.67%. Results show that (1) the parameterization using the average cut-off diameter Dm, which is derived from the various measured PNSD and NCCN, provides the best estimate of NCCN, with coefficient of determination, R2 = 0.70-0.90 and NCCN,cal/NCCN,obs = 0.92-1.11, followed by the method of combining an average size-resolved activation curve with the PNSD, with R2 = 0.71-0.91 and NCCN,cal/NCCN,obs = 0.71-0.91; average D50 together with the PNSD also provides a rational scheme for NCCN prediction, with NCCN,cal/NCCN,obs = 0.86-0.94 and R2 = 0.70-0.89; (2) the method of parameterizing CCN spectra, though straightforward, has limits under polluted conditions. Reasonable NCCN estimate could only be obtained at high S (R2 ≥ 0.85 at S = 0.39% and 0.67%). (3) For the method employing the bulk activation ratio ARB(S), NCCN are substantially overestimated by using total mode-based ARB(S) (NCCN,cal/NCCN,obs = 0.94-1.39, R2 = 0.17-0.67), while applying ammonium sulfate-based ARB(S) yields improved CCN predictions (NCCN,cal/NCCN,obs = 0.91-1.11, R2 = 0.70-0.91). In southern China, when determining the parameterization schemes in climate models, it is first recommended to use the method of average cut-off diameter or SRAR, with the various measured PNSD to predict NCCN. Besides, the method using ammonium sulfate-based ARB(S) and parameterizing CCN spectra
1. Evaluation of Cloud Parameterizations in a High Resolution Atmospheric General Circulation Model Using ARM Data
SciTech Connect
Govindasamy, B; Duffy, P
2002-04-12
Typical state of the art atmospheric general circulation models used in climate change studies have horizontal resolution of approximately 300 km. As computing power increases, many climate modeling groups are working toward enhancing the resolution of global models. An important issue that arises when resolution of a model is changed is whether cloud and convective parameterizations, which were developed for use at coarser resolutions, will need to be reformulated or re-tuned. We propose to investigate this issue and specifically cloud statistics using ARM data. The data streams produced by highly instrumented sections of Cloud and Radiation Testbeds (CART) of ARM program will provide a significant aid in the evaluation of cloud and convection parameterization in high-resolution models. Recently, we have performed multiyear global-climate simulations at T170 and T239 resolutions, corresponding to grid cell sizes of 0.7{sup 0} and 0.5{sup 0} respectively, using the NCAR Community Climate Model. We have also a performed climate change simulation at T170. On the scales of a T42 grid cell (300 km) and larger, nearly all quantities we examined in T170 simulation agree better with observations in terms of spatial patterns than do results in a comparable simulation at T42. Increasing the resolution to T239 brings significant further improvement. At T239, the high-resolution model grid cells approach the dimensions of the highly instrumented sections of ARM Cloud and Radiation Testbed (CART) sites. We propose to form a cloud climatology using ARM data for its CART sites and evaluate cloud statistics of the NCAR Community Atmosphere Model (CAM) at higher resolutions over those sites using this ARM cloud climatology. We will then modify the physical parameterizations of CAM for better agreement with ARM data. We will work closely with NCAR in modifying the parameters in cloud and convection parameterizations for the high-resolution model. Our proposal to evaluate the cloud
2. An analysis of MM5 sensitivity to different parameterizations for high-resolution climate simulations
Argüeso, D.; Hidalgo-Muñoz, J. M.; Gámiz-Fortis, S. R.; Esteban-Parra, M. J.; Castro-Díez, Y.
2009-04-01
An evaluation of MM5 mesoscale model sensitivity to different parameterizations schemes is presented in terms of temperature and precipitation for high-resolution integrations over Andalusia (South of Spain). As initial and boundary conditions ERA-40 Reanalysis data are used. Two domains were used, a coarse one with dimensions of 55 by 60 grid points with spacing of 30 km and a nested domain of 48 by 72 grid points grid spaced 10 km. Coarse domain fully covers Iberian Peninsula and Andalusia fits loosely in the finer one. In addition to parameterization tests, two dynamical downscaling techniques have been applied in order to examine the influence of initial conditions on RCM long-term studies. Regional climate studies usually employ continuous integration for the period under survey, initializing atmospheric fields only at the starting point and feeding boundary conditions regularly. An alternative approach is based on frequent re-initialization of atmospheric fields; hence the simulation is divided in several independent integrations. Altogether, 20 simulations have been performed using varying physics options, of which 4 were fulfilled applying the re-initialization technique. Surface temperature and accumulated precipitation (daily and monthly scale) were analyzed for a 5-year period covering from 1990 to 1994. Results have been compared with daily observational data series from 110 stations for temperature and 95 for precipitation Both daily and monthly average temperatures are generally well represented by the model. Conversely, daily precipitation results present larger deviations from observational data. However, noticeable accuracy is gained when comparing with monthly precipitation observations. There are some especially conflictive subregions where precipitation is scarcely captured, such as the Southeast of the Iberian Peninsula, mainly due to its extremely convective nature. Regarding parameterization schemes performance, every set provides very
3. Quantification of the uncertainties in soil and vegetation parameterizations for regional climate predictions
Breil, Marcus; Schädler, Gerd
2016-04-01
The aim of the german research program MiKlip II is the development of an operational climate prediction system that can provide reliable forecasts on a decadal time scale. Thereby, one goal of MiKlip II is to investigate the feasibility of regional climate predictions. Results of recent studies indicate that the regional climate is significantly affected by the interactions between the soil, the vegetation and the atmosphere. Thus, within the framework of MiKlip II a workpackage was established to assess the impact of these interactions on the regional decadal climate predictability. In a Regional Climate Model (RCM) the soil-vegetation-atmosphere interactions are represented in a Land Surface Model (LSM). Thereby, the LSM describes the current state of the land surface by calculating the soil temperature, the soil water content and the turbulent heat fluxes, serving the RCM as lower boundary condition. To be able to solve the corresponding equations, soil and vegetation processes are parameterized within the LSM. Such parameterizations are mainly derived from observations. But in most cases observations are temporally and spatially limited and consequently not able to represent the diversity of nature completely. Thus, soil and vegetation parameterizations always exhibit a certain degree of uncertainty. In the presented study, the uncertainties within a LSM are assessed by stochastic variations of the relevant parameterizations in VEG3D, a LSM developed at the Karlsruhe Institute of Technology (KIT). In a first step, stand-alone simulations of VEG3D are realized with varying soil and vegetation parameters, to identify sensitive model parameters. In a second step, VEG3D is coupled to the RCM COSMO-CLM. With this new model system regional decadal hindcast simulations, driven by global simulations of the Max-Planck-Institute for Meteorology Earth System Model (MPI-ESM), are performed for the CORDEX-EU domain in a resolution of 0.22°. The identified sensitive model
4. A new parameterization of the post-fire snow albedo effect
Gleason, K. E.; Nolin, A. W.
2013-12-01
Mountain snowpack serves as an important natural reservoir of water: recharging aquifers, sustaining streams, and providing important ecosystem services. Reduced snowpacks and earlier snowmelt have been shown to affect fire size, frequency, and severity in the western United States. In turn, wildfire disturbance affects patterns of snow accumulation and ablation by reducing canopy interception, increasing turbulent fluxes, and modifying the surface radiation balance. Recent work shows that after a high severity forest fire, approximately 60% more solar radiation reaches the snow surface due to the reduction in canopy density. Also, significant amounts of pyrogenic carbon particles and larger burned woody debris (BWD) are shed from standing charred trees, which concentrate on the snowpack, darken its surface, and reduce snow albedo by 50% during ablation. Although the post-fire forest environment drives a substantial increase in net shortwave radiation at the snowpack surface, driving earlier and more rapid melt, hydrologic models do not explicitly incorporate forest fire disturbance effects to snowpack dynamics. The objective of this study was to parameterize the post-fire snow albedo effect due to BWD deposition on snow to better represent forest fire disturbance in modeling of snow-dominated hydrologic regimes. Based on empirical results from winter experiments, in-situ snow monitoring, and remote sensing data from a recent forest fire in the Oregon High Cascades, we characterized the post-fire snow albedo effect, and developed a simple parameterization of snowpack albedo decay in the post-fire forest environment. We modified the recession coefficient in the algorithm: α = α0 + K exp (-nr) where α = snowpack albedo, α0 = minimum snowpack albedo (≈0.4), K = constant (≈ 0.44), -n = number of days since last major snowfall, r = recession coefficient [Rohrer and Braun, 1994]. Our parameterization quantified BWD deposition and snow albedo decay rates and
5. Further Evaluation of an Urban Canopy Parameterization using VTMX and Urban 2000 Data
SciTech Connect
Chin, H S; Leach, M J
2004-06-04
Almost two-thirds of the U.S. population live in urbanized areas occupying less than 2% of the landmass. Similar statistics of urbanization exists in other parts of the world. With the rapid growth of the world population, urbanization appears to be an important issue on environmental and health aspects. As a result, the interaction between the urban region and atmospheric processes becomes a very complex problem. Further understanding of this interaction via the surface and/or atmosphere is of importance to improve the weather forecast, and to minimize the loss caused by the weather-related events, or even by the chemical-biological threat. To this end, Brown and Willaims, (1998) first developed an urban canopy scheme to parameterize the urban infrastructure effect. This parameterization accounts for the effects of drag, turbulent production, radiation balance, and anthropogenic and rooftop heating. Further modification was made and tested in our recent sensitivity study for an idealized case using a mesoscale model. Results indicated that the addition of the rooftop surface energy equation enables this parameterization to more realistically simulate the urban infrastructure impact (Chin et al., 2000). To further improve the representation of the urban effect in the mesoscale model, the USGS land-use data with different resolutions (200 and 30 meters) are adopted to derive the urban parameters via a look-up table approach (Leone et al., 2002; Chin et al., 2004). This approach can provide us the key parameters for urban infrastructure and urban surface characteristics to drive the urban canopy parameterization with geographic and temporal dependence. These urban characteristics include urban fraction, roof fraction, building height, anthropogenic heating, surface albedo, surface wetness, and surface roughness. The objective of this study is to evaluate the modified urban canopy parameterization (UCP) with the observed measurements. Another objective is to
6. Effects of cloud parameterization on the simulation of climate changes in the GISS GCM
SciTech Connect
Yao, M.S.; Del Genio, A.D.
1999-03-01
Climate changes obtained from five doubled CO{sub 2} experiments with different parameterizations of large-scale clouds and moist convection are studied by use of the Goddard Institute for Space Studies (GISS) GCM at 4{degree} lat x 5{degree} long resolution. The baseline for the experiments is GISS Model II, which uses a diagnostic cloud scheme with fixed optical properties and a convection scheme with fixed cumulus mass fluxes and no downdrafts. The global and annual mean surface air temperature change ({Delta}T{sub s}) of 4.2 C obtained by Hansen et al. using the Model II physics at 8{degree} lat x 10{degree} long resolution is reduced to 3.55 C at the finer resolution. This is due to a significant reduction of tropical cirrus clouds in the warmer climate when a finer resolution is used, despite the fact that the relative humidity increases there with a doubling of CO{sub 2}. When the new moist convection parameterization of Del Genio and Yao and prognostic large-scale cloud parameterization of Del Genio et al. are used, {Delta}T{sub s} is reduced to 3.09 C from 3.55 C. This is the net result of the inclusion of the feedback of cloud optical thickness and phase change of cloud water, and the presence of areally extensive cumulus anvil clouds. Without the optical thickness feedback, {Delta}T{sub s} is further reduced to 2.74 C, suggesting that this feedback is positive overall. Without anvil clouds, {Delta}T{sub s} is increased from 3.09 to 3.7 C, suggesting that anvil clouds of large optical thickness reduce the climate sensitivity. The net effect of using the new large-scale cloud parameterization without including the detrainment of convective cloud water is a slight increase of {Delta}T{sub s} from 3.56 to 3.7 C. The net effect of using the new moist convection parameterization without anvil clouds is insignificant.
7. Analyses of the stratospheric dynamics simulated by a GCM with a stochastic nonorographic gravity wave parameterization
Serva, Federico; Cagnazzo, Chiara; Riccio, Angelo
2016-04-01
The effects of the propagation and breaking of atmospheric gravity waves have long been considered crucial for their impact on the circulation, especially in the stratosphere and mesosphere, between heights of 10 and 110 km. These waves, that in the Earth's atmosphere originate from surface orography (OGWs) or from transient (nonorographic) phenomena such as fronts and convective processes (NOGWs), have horizontal wavelengths between 10 and 1000 km, vertical wavelengths of several km, and frequencies spanning from minutes to hours. Orographic and nonorographic GWs must be accounted for in climate models to obtain a realistic simulation of the stratosphere in both hemispheres, since they can have a substantial impact on circulation and temperature, hence an important role in ozone chemistry for chemistry-climate models. Several types of parameterization are currently employed in models, differing in the formulation and for the values assigned to parameters, but the common aim is to quantify the effect of wave breaking on large-scale wind and temperature patterns. In the last decade, both global observations from satellite-borne instruments and the outputs of very high resolution climate models provided insight on the variability and properties of gravity wave field, and these results can be used to constrain some of the empirical parameters present in most parameterization scheme. A feature of the NOGW forcing that clearly emerges is the intermittency, linked with the nature of the sources: this property is absent in the majority of the models, in which NOGW parameterizations are uncoupled with other atmospheric phenomena, leading to results which display lower variability compared to observations. In this work, we analyze the climate simulated in AMIP runs of the MAECHAM5 model, which uses the Hines NOGW parameterization and with a fine vertical resolution suitable to capture the effects of wave-mean flow interaction. We compare the results obtained with two
8. Proton Nucleus Elastic Scattering Data.
1993-08-18
Version 00 The Proton Nucleus Elastic Scattering Data file PNESD contains the numerical data and the related bibliography for the differential elastic cross sections, polarization and integral nonelastic cross sections for elastic proton-nucleus scattering.
9. Interface scattering in polycrystalline thermoelectrics
SciTech Connect
2014-03-28
We study the effect of electron and phonon interface scattering on the thermoelectric properties of disordered, polycrystalline materials (with grain sizes larger than electron and phonons' mean free path). Interface scattering of electrons is treated with a Landauer approach, while that of phonons is treated with the diffuse mismatch model. The interface scattering is embedded within a diffusive model of bulk transport, and we show that, for randomly arranged interfaces, the overall system is well described by effective medium theory. Using bulk parameters similar to those of PbTe and a square barrier potential for the interface electron scattering, we identify the interface scattering parameters for which the figure of merit ZT is increased. We find the electronic scattering is generally detrimental due to a reduction in electrical conductivity; however, for sufficiently weak electronic interface scattering, ZT is enhanced due to phonon interface scattering.
10. Joyce and Ulysses: integrated and user-friendly tools for the parameterization of intramolecular force fields from quantum mechanical data.
PubMed
Barone, Vincenzo; Cacelli, Ivo; De Mitri, Nicola; Licari, Daniele; Monti, Susanna; Prampolini, Giacomo
2013-03-21
The Joyce program is augmented with several new features, including the user friendly Ulysses GUI, the possibility of complete excited state parameterization and a more flexible treatment of the force field electrostatic terms. A first validation is achieved by successfully comparing results obtained with Joyce2.0 to literature ones, obtained for the same set of benchmark molecules. The parameterization protocol is also applied to two other larger molecules, namely nicotine and a coumarin based dye. In the former case, the parameterized force field is employed in molecular dynamics simulations of solvated nicotine, and the solute conformational distribution at room temperature is discussed. Force fields parameterized with Joyce2.0, for both the dye's ground and first excited electronic states, are validated through the calculation of absorption and emission vertical energies with molecular mechanics optimized structures. Finally, the newly implemented procedure to handle polarizable force fields is discussed and applied to the pyrimidine molecule as a test case. PMID:23389748
11. Joyce and Ulysses: integrated and user-friendly tools for the parameterization of intramolecular force fields from quantum mechanical data.
PubMed
Barone, Vincenzo; Cacelli, Ivo; De Mitri, Nicola; Licari, Daniele; Monti, Susanna; Prampolini, Giacomo
2013-03-21
The Joyce program is augmented with several new features, including the user friendly Ulysses GUI, the possibility of complete excited state parameterization and a more flexible treatment of the force field electrostatic terms. A first validation is achieved by successfully comparing results obtained with Joyce2.0 to literature ones, obtained for the same set of benchmark molecules. The parameterization protocol is also applied to two other larger molecules, namely nicotine and a coumarin based dye. In the former case, the parameterized force field is employed in molecular dynamics simulations of solvated nicotine, and the solute conformational distribution at room temperature is discussed. Force fields parameterized with Joyce2.0, for both the dye's ground and first excited electronic states, are validated through the calculation of absorption and emission vertical energies with molecular mechanics optimized structures. Finally, the newly implemented procedure to handle polarizable force fields is discussed and applied to the pyrimidine molecule as a test case.
12. An intermediate process-based fire parameterization in Dynamic Global Vegetation Model
Li, F.; Zeng, X.
2011-12-01
An intermediate process-based fire parameterization has been developed for global fire simulation. It fits the framework of Dynamic Global Vegetation Model (DGVM) which has been a pivot component in Earth System Model (ESM). The fire parameterization comprises three parts: fire occurrence, fire spread, and fire impact. In the first part, the number of fires is determined by ignition counts due to anthropogenic and natural causes and three constraints: fuel load, fuel moisture, and human suppression. Human caused ignition and suppression is explicitly considered as a nonlinear function of population density. The fire counts rather than fire occurrence probability is estimated to avoid underestimating the observed high burned area fraction in tropical savannas where fire occurs frequently. In the second part, post-fire region is assumed to be elliptical in shape with the wind direction along the major axis and the point of ignition at one of the foci. Burned area is determined by fire spread rate,fire duration, and fire counts. Mathematical characteristics of ellipse and some mathematical derivations are used to avoid redundant and unreasonable equations and assumptions in the CTEM-FIRE and make the parameterization equations self-consistently. In the third part, the impact of fire on vegetation component and structure, carbon cycle, trace gases and aerosol emissions are taken into account. The new estimates of trace gas and aerosol emissions due to biomass burning offers an interface with aerosol and atmospheric chemistry model in ESMs. Furthermore, in the new fire parameterization, fire occurrence part and fire spread part can be updated hourly or daily, and fire impact part can be updated daily, monthly, or annually. Its flexibility in selection of time-step length makes it easily applied to various DGVMs. The improved Community Land Model 3.0's Dynamic Global Vegetation Model (CLM-DGVM) is used as the model platform to assess the global performance of the new
13. Construction of an integrated Raman- and angular-scattering microscope.
PubMed
Smith, Zachary J; Berger, Andrew J
2009-04-01
We report on the construction of a multimodal microscope platform capable of gathering both elastically and inelastically scattered light from a 38 mum(2) region in both epi- and transillumination geometries. Simultaneous monitoring of elastic and inelastic scattering from a microscopic region allows noninvasive characterization of the chemistry and morphology of a living sample without the need for exogenous dyes or labels, thus allowing measurements to be made longitudinally in time on the same sample as it evolves naturally. A sample is illuminated either from above or below with a focused 785 nm TEM(00) mode laser beam, with elastic and inelastic scattering collected by two separate measurement arms. The measurements may be made either simultaneously, if identical illumination geometries are used, or sequentially, if the two modalities utilize opposing illumination paths. In the inelastic arm, Stokes-shifted light is dispersed by a spectrograph onto a charge-coupled device (CCD) array. In the elastic scattering collection arm, a relay system images the microscope's back aperture onto a CCD array. Postprocessing of the inelastic scattering to remove fluorescence signals yields high quality Raman spectra that report on the sample's chemical makeup. Comparison of the elastically scattered pupil images to generalized Lorenz-Mie theory yields estimated size distributions of scatterers within the sample. PMID:19405678
14. Coordinated Parameterization Development and Large-Eddy Simulation for Marine and Arctic Cloud-Topped Boundary Layers
NASA Technical Reports Server (NTRS)
Bretherton, Christopher S.
1998-01-01
The goal of this project was to compare observations of marine and arctic boundary layers with (i) parameterization systems used in climate and weather forecast models, and (ii) two and three dimensional eddy resolving (LES) models for turbulent fluid flow. Based on this comparison, we hoped to better understand, predict, and parameterize the boundary layer structure and cloud amount, type and thickness as functions of large scale conditions that are predicted by global climate models.
15. Predicting X-ray diffuse scattering from translation–libration–screw structural ensembles
DOE PAGES
Van Benschoten, Andrew H.; Afonine, Pavel V.; Terwilliger, Thomas C.; Wall, Michael E.; Jackson, Colin J.; Sauter, Nicholas K.; Adams, Paul D.; Urzhumtsev, Alexandre; Fraser, James S.
2015-07-28
Identifying the intramolecular motions of proteins and nucleic acids is a major challenge in macromolecular X-ray crystallography. Because Bragg diffraction describes the average positional distribution of crystalline atoms with imperfect precision, the resulting electron density can be compatible with multiple models of motion. Diffuse X-ray scattering can reduce this degeneracy by reporting on correlated atomic displacements. Although recent technological advances are increasing the potential to accurately measure diffuse scattering, computational modeling and validation tools are still needed to quantify the agreement between experimental data and different parameterizations of crystalline disorder. A new tool, phenix.diffuse, addresses this need by employing Guinier'smore » equation to calculate diffuse scattering from Protein Data Bank (PDB)-formatted structural ensembles. As an example case, phenix.diffuse is applied to translation–libration–screw (TLS) refinement, which models rigid-body displacement for segments of the macromolecule. To enable the calculation of diffuse scattering from TLS-refined structures, phenix.tls_as_xyz builds multi-model PDB files that sample the underlying T, L and S tensors. In the glycerophosphodiesterase GpdQ, alternative TLS-group partitioning and different motional correlations between groups yield markedly dissimilar diffuse scattering maps with distinct implications for molecular mechanism and allostery. These methods demonstrate how, in principle, X-ray diffuse scattering could extend macromolecular structural refinement, validation and analysis.« less
16. Predicting X-ray diffuse scattering from translation–libration–screw structural ensembles
PubMed Central
Van Benschoten, Andrew H.; Afonine, Pavel V.; Terwilliger, Thomas C.; Wall, Michael E.; Jackson, Colin J.; Sauter, Nicholas K.; Adams, Paul D.; Urzhumtsev, Alexandre; Fraser, James S.
2015-01-01
Identifying the intramolecular motions of proteins and nucleic acids is a major challenge in macromolecular X-ray crystallography. Because Bragg diffraction describes the average positional distribution of crystalline atoms with imperfect precision, the resulting electron density can be compatible with multiple models of motion. Diffuse X-ray scattering can reduce this degeneracy by reporting on correlated atomic displacements. Although recent technological advances are increasing the potential to accurately measure diffuse scattering, computational modeling and validation tools are still needed to quantify the agreement between experimental data and different parameterizations of crystalline disorder. A new tool, phenix.diffuse, addresses this need by employing Guinier’s equation to calculate diffuse scattering from Protein Data Bank (PDB)-formatted structural ensembles. As an example case, phenix.diffuse is applied to translation–libration–screw (TLS) refinement, which models rigid-body displacement for segments of the macromolecule. To enable the calculation of diffuse scattering from TLS-refined structures, phenix.tls_as_xyz builds multi-model PDB files that sample the underlying T, L and S tensors. In the glycerophosphodiesterase GpdQ, alternative TLS-group partitioning and different motional correlations between groups yield markedly dissimilar diffuse scattering maps with distinct implications for molecular mechanism and allostery. These methods demonstrate how, in principle, X-ray diffuse scattering could extend macromolecular structural refinement, validation and analysis. PMID:26249347
17. A Relativistic Multiple Scattering Theory for Nucleus-Nucleus Collisions with Delta Resonance Coupling
Werneth, Charles; Maung Maung, Khin; Norbury, John
2012-10-01
Non-relativistic multiple scattering theories (NRMST) are formulated by separating the unperturbed Hamiltonian from the interaction and writing the Lippmann-Schwinger equation as an infinite series in the multiple sums of pseudo two-body operators, known as the Watson tau-operators. The advantage of using the multiple scattering theory (MST) is that the pseudo two-body operators are often well approximated by free two-body nucleon-nucleon operators, which are obtained from parameterizations of experimental data. Relativistic theories are needed to properly describe the production of new particles, such as pions, from nucleus-nucleus collisions. Relativistic multiple scattering theories (RMST) have been developed for nucleon-nucleus scattering; however, no RMST for nucleus-nucleus scattering has yet been derived.footnotetextMaung K M, Norbury J W, and Coleman T 2007 J. Phys. G 34 1861. The purpose of this research is to derive an RMST for nucleus-nucleus scattering and to include delta degrees of freedom in the interaction, the minimum requirement for pion production.
18. Predicting X-ray diffuse scattering from translation–libration–screw structural ensembles
SciTech Connect
Van Benschoten, Andrew H.; Afonine, Pavel V.; Terwilliger, Thomas C.; Wall, Michael E.; Jackson, Colin J.; Sauter, Nicholas K.; Adams, Paul D.; Urzhumtsev, Alexandre; Fraser, James S.
2015-07-28
Identifying the intramolecular motions of proteins and nucleic acids is a major challenge in macromolecular X-ray crystallography. Because Bragg diffraction describes the average positional distribution of crystalline atoms with imperfect precision, the resulting electron density can be compatible with multiple models of motion. Diffuse X-ray scattering can reduce this degeneracy by reporting on correlated atomic displacements. Although recent technological advances are increasing the potential to accurately measure diffuse scattering, computational modeling and validation tools are still needed to quantify the agreement between experimental data and different parameterizations of crystalline disorder. A new tool, phenix.diffuse, addresses this need by employing Guinier's equation to calculate diffuse scattering from Protein Data Bank (PDB)-formatted structural ensembles. As an example case, phenix.diffuse is applied to translation–libration–screw (TLS) refinement, which models rigid-body displacement for segments of the macromolecule. To enable the calculation of diffuse scattering from TLS-refined structures, phenix.tls_as_xyz builds multi-model PDB files that sample the underlying T, L and S tensors. In the glycerophosphodiesterase GpdQ, alternative TLS-group partitioning and different motional correlations between groups yield markedly dissimilar diffuse scattering maps with distinct implications for molecular mechanism and allostery. These methods demonstrate how, in principle, X-ray diffuse scattering could extend macromolecular structural refinement, validation and analysis.
19. Predicting X-ray diffuse scattering from translation-libration-screw structural ensembles.
PubMed
Van Benschoten, Andrew H; Afonine, Pavel V; Terwilliger, Thomas C; Wall, Michael E; Jackson, Colin J; Sauter, Nicholas K; Adams, Paul D; Urzhumtsev, Alexandre; Fraser, James S
2015-08-01
Identifying the intramolecular motions of proteins and nucleic acids is a major challenge in macromolecular X-ray crystallography. Because Bragg diffraction describes the average positional distribution of crystalline atoms with imperfect precision, the resulting electron density can be compatible with multiple models of motion. Diffuse X-ray scattering can reduce this degeneracy by reporting on correlated atomic displacements. Although recent technological advances are increasing the potential to accurately measure diffuse scattering, computational modeling and validation tools are still needed to quantify the agreement between experimental data and different parameterizations of crystalline disorder. A new tool, phenix.diffuse, addresses this need by employing Guinier's equation to calculate diffuse scattering from Protein Data Bank (PDB)-formatted structural ensembles. As an example case, phenix.diffuse is applied to translation-libration-screw (TLS) refinement, which models rigid-body displacement for segments of the macromolecule. To enable the calculation of diffuse scattering from TLS-refined structures, phenix.tls_as_xyz builds multi-model PDB files that sample the underlying T, L and S tensors. In the glycerophosphodiesterase GpdQ, alternative TLS-group partitioning and different motional correlations between groups yield markedly dissimilar diffuse scattering maps with distinct implications for molecular mechanism and allostery. These methods demonstrate how, in principle, X-ray diffuse scattering could extend macromolecular structural refinement, validation and analysis.
20. Scattering fidelity in elastodynamics
Gorin, T.; Seligman, T. H.; Weaver, R. L.
2006-01-01
The recent introduction of the concept of scattering fidelity causes us to revisit the experiment by Lobkis and Weaver [Phys. Rev. Lett. 90, 254302 (2003)]. There, the “distortion” of the coda of an acoustic signal is measured under temperature changes. This quantity is, in fact, the negative logarithm of scattering fidelity. We reanalyze their experimental data for two samples, and we find good agreement with random matrix predictions for the standard fidelity. Usually, one may expect such an agreement for chaotic systems, only. While the first sample may indeed be assumed chaotic, for the second sample, a perfect cuboid, such an agreement is surprising. For the first sample, the random matrix analysis yields perturbation strengths compatible with semiclassical predictions. For the cuboid, the measured perturbation strengths are by a common factor of (5)/(3) too large. Apart from that, the experimental curves for the distortion are well reproduced.
1. Coherent Scatter Imaging Measurements
Ur Rehman, Mahboob
In conventional radiography, anatomical information of the patients can be obtained, distinguishing different tissue types, e.g. bone and soft tissue. However, it is difficult to obtain appreciable contrast between two different types of soft tissues. Instead, coherent x-ray scattering can be utilized to obtain images which can differentiate between normal and cancerous cells of breast. An x-ray system using a conventional source and simple slot apertures was tested. Materials with scatter signatures that mimic breast cancer were buried in layers of fat of increasing thickness and imaged. The result showed that the contrast and signal to noise ratio (SNR) remained high even with added fat layers and short scan times.
2. Scattering problems in elastodynamics
Diatta, Andre; Kadic, Muamer; Wegener, Martin; Guenneau, Sebastien
2016-09-01
In electromagnetism, acoustics, and quantum mechanics, scattering problems can routinely be solved numerically by virtue of perfectly matched layers (PMLs) at simulation domain boundaries. Unfortunately, the same has not been possible for general elastodynamic wave problems in continuum mechanics. In this Rapid Communication, we introduce a corresponding scattered-field formulation for the Navier equation. We derive PMLs based on complex-valued coordinate transformations leading to Cosserat elasticity-tensor distributions not obeying the minor symmetries. These layers are shown to work in two dimensions, for all polarizations, and all directions. By adaptative choice of the decay length, the deep subwavelength PMLs can be used all the way to the quasistatic regime. As demanding examples, we study the effectiveness of cylindrical elastodynamic cloaks of the Cosserat type and approximations thereof.
3. Syzygies probing scattering amplitudes
Chen, Gang; Liu, Junyu; Xie, Ruofei; Zhang, Hao; Zhou, Yehao
2016-09-01
We propose a new efficient algorithm to obtain the locally minimal generating set of the syzygies for an ideal, i.e. a generating set whose proper subsets cannot be generating sets. Syzygy is a concept widely used in the current study of scattering amplitudes. This new algorithm can deal with more syzygies effectively because a new generation of syzygies is obtained in each step and the irreducibility of this generation is also verified in the process. This efficient algorithm can also be applied in getting the syzygies for the modules. We also show a typical example to illustrate the potential application of this method in scattering amplitudes, especially the Integral-By-Part(IBP) relations of the characteristic two-loop diagrams in the Yang-Mills theory.
4. Acoustic bubble removal method
NASA Technical Reports Server (NTRS)
Trinh, E. H.; Elleman, D. D.; Wang, T. G. (Inventor)
1983-01-01
A method is described for removing bubbles from a liquid bath such as a bath of molten glass to be used for optical elements. Larger bubbles are first removed by applying acoustic energy resonant to a bath dimension to drive the larger bubbles toward a pressure well where the bubbles can coalesce and then be more easily removed. Thereafter, submillimeter bubbles are removed by applying acoustic energy of frequencies resonant to the small bubbles to oscillate them and thereby stir liquid immediately about the bubbles to facilitate their breakup and absorption into the liquid.
5. Anthralin stain removal.
PubMed
Wang, J C; Krazmien, R J; Dahlheim, C E; Patel, B
1986-11-01
Results of an anthralin stain removal study on white 65% polyester/35% cotton, white 100% polyester, white 100% cotton, a white shower curtain, white tile with crevice, and white ceramic shower tile are reported. An optimum stain removal technic was developed by using a 10-minute soak in full-strength chlorine bleach (Good Measure or Clorox) followed by a water rinse and air drying. This technic completely removed all stains of 24-hour duration from the test fabrics. The stain removal test on shower curtains, floor tiles, and ceramic shower tiles was also discussed.
6. Molecular-beam scattering
SciTech Connect
Vernon, M.F.
1983-07-01
The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N/sub 2/ from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl ..-->.. NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2/sup 2/P/sub 3/2/) and Na(3/sup 2/P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included.
7. Dynamic light scattering microscopy
Dzakpasu, Rhonda
An optical microscope technique, dynamic light scattering microscopy (DLSM) that images dynamically scattered light fluctuation decay rates is introduced. Using physical optics we show theoretically that within the optical resolution of the microscope, relative motions between scattering centers are sufficient to produce significant phase variations resulting in interference intensity fluctuations in the image plane. The time scale for these intensity fluctuations is predicted. The spatial coherence distance defining the average distance between constructive and destructive interference in the image plane is calculated and compared with the pixel size. We experimentally tested DLSM on polystyrene latex nanospheres and living macrophage cells. In order to record these rapid fluctuations, on a slow progressive scan CCD camera, we used a thin laser line of illumination on the sample such that only a single column of pixels in the CCD camera is illuminated. This allowed the use of the rate of the column-by-column readout transfer process as the acquisition rate of the camera. This manipulation increased the data acquisition rate by at least an order of magnitude in comparison to conventional CCD cameras rates defined by frames/s. Analysis of the observed fluctuations provides information regarding the rates of motion of the scattering centers. These rates, acquired from each position on the sample are used to create a spatial map of the fluctuation decay rates. Our experiments show that with this technique, we are able to achieve a good signal-to-noise ratio and can monitor fast intensity fluctuations, on the order of milliseconds. DLSM appears to provide dynamic information about fast motions within cells at a sub-optical resolution scale and provides a new kind of spatial contrast.
8. Calculating scattering amplitudes efficiently
SciTech Connect
Dixon, L.
1996-01-01
We review techniques for more efficient computation of perturbative scattering amplitudes in gauge theory, in particular tree and one- loop multi-parton amplitudes in QCD. We emphasize the advantages of (1) using color and helicity information to decompose amplitudes into smaller gauge-invariant pieces, and (2) exploiting the analytic properties of these pieces, namely their cuts and poles. Other useful tools include recursion relations, special gauges and supersymmetric rearrangements. 46 refs., 11 figs.
9. Molecular-beam scattering
Vernon, M. F.
1983-07-01
The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N2 from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HC1 (FEMALE) NAC1 + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2(2)P/sub 3/2/) and Na(3(2)P/sub 3/2) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included.
10. Concurrent electromagnetic scattering analysis
NASA Technical Reports Server (NTRS)
Patterson, Jean E.; Cwik, Tom; Ferraro, Robert D.; Jacobi, Nathan; Liewer, Paulett C.; Lockhart, Thomas G.; Lyzenga, Gregory A.; Parker, Jay
1989-01-01
The computational power of the hypercube parallel computing architecture is applied to the solution of large-scale electromagnetic scattering and radiation problems. Three analysis codes have been implemented. A Hypercube Electromagnetic Interactive Analysis Workstation was developed to aid in the design and analysis of metallic structures such as antennas and to facilitate the use of these analysis codes. The workstation provides a general user environment for specification of the structure to be analyzed and graphical representations of the results.
11. Neutron scattering in Australia
SciTech Connect
Knott, R.B.
1994-12-31
Neutron scattering techniques have been part of the Australian scientific research community for the past three decades. The High Flux Australian Reactor (HIFAR) is a multi-use facility of modest performance that provides the only neutron source in the country suitable for neutron scattering. The limitations of HIFAR have been recognized and recently a Government initiated inquiry sought to evaluate the future needs of a neutron source. In essence, the inquiry suggested that a delay of several years would enable a number of key issues to be resolved, and therefore a more appropriate decision made. In the meantime, use of the present source is being optimized, and where necessary research is being undertaken at major overseas neutron facilities either on a formal or informal basis. Australia has, at present, a formal agreement with the Rutherford Appleton Laboratory (UK) for access to the spallation source ISIS. Various aspects of neutron scattering have been implemented on HIFAR, including investigations of the structure of biological relevant molecules. One aspect of these investigations will be presented. Preliminary results from a study of the interaction of the immunosuppressant drug, cyclosporin-A, with reconstituted membranes suggest that the hydrophobic drug interdigitated with lipid chains.
12. Timelike Compton Scattering
Mkrtchyan, Arthur; Albayrak, Ibrahim; Horn, Tanja; Nadel-Turonski, Pawel
2015-04-01
Deeply Virtual Comtpon Scattering (DVCS) is deemed the simplest and cleanest way to access the Generalized Parton Distributions (GPDs) of the nucleon. The DVCS process interferes with the Bethe-Heitler process allowing one to access the DVCS amplitudes. The imaginary part of the Compton amplitude is now relatively well understood, primarily through measurements of DVCS. However, much less is known about the real part of the amplitude. Time-like Compton Scattering (TCS) is the inverse process of DVCS and provides a new and promising way for probing the real part of the amplitude, and so constraining GPDs. Comparing data from Time-like Compton Scattering and the space-like DVCS process will also allow for testing the universality of GPDs. First studies of TCS using real tagged and quasi-real untagged photons were carried out at Jefferson Lab 6 GeV. In this talk, preliminary results on asymmetries and extraction of the real part of the CFF using photoproduction data and a comparison to electroproduction data will be presented. We will also discuss future plans for dilepton production at Jefferson Lab 12 GeV. Supported in part by NSF Grant PHY-1306227.
13. Nanowire Electron Scattering Spectroscopy
NASA Technical Reports Server (NTRS)
Hunt, Brian; Bronikowsky, Michael; Wong, Eric; VonAllmen, Paul; Oyafuso, Fablano
2009-01-01
Nanowire electron scattering spectroscopy (NESS) has been proposed as the basis of a class of ultra-small, ultralow-power sensors that could be used to detect and identify chemical compounds present in extremely small quantities. State-of-the-art nanowire chemical sensors have already been demonstrated to be capable of detecting a variety of compounds in femtomolar quantities. However, to date, chemically specific sensing of molecules using these sensors has required the use of chemically functionalized nanowires with receptors tailored to individual molecules of interest. While potentially effective, this functionalization requires labor-intensive treatment of many nanowires to sense a broad spectrum of molecules. In contrast, NESS would eliminate the need for chemical functionalization of nanowires and would enable the use of the same sensor to detect and identify multiple compounds. NESS is analogous to Raman spectroscopy, the main difference being that in NESS, one would utilize inelastic scattering of electrons instead of photons to determine molecular vibrational energy levels. More specifically, in NESS, one would exploit inelastic scattering of electrons by low-lying vibrational quantum states of molecules attached to a nanowire or nanotube.
14. Light Scattering by Spheroids
Xie, Ya-Ming; Ji, Xia
Nowadays, with the development of technology, particles with size at nanoscale have been synthesized in experiments. It is noticed that anisotropy is an unavoidable problem in the production of nanospheres. Besides, nonspherical nanoparticles have also been extensively used in experiments. Comparing with spherical model, spheroidal model can give a better description for the characteristics of nonspherical particles. Thus the study of analytical solution for light scattering by spheroidal particles has practical implications. By expanding incident, scattered, and transmitted electromagnetic fields in terms of appropriate vector spheroidal wave functions, an analytic solution is obtained to the problem of light scattering by spheroids. Unknown field expansion coefficients can be determined with the combination of boundary conditions and rotational-translational addition theorems for vector spheroidal wave functions. Based on the theoretical derivation, a Fortran code has been developed to calculate the extinction cross section and field distribution, whose results agree well with those obtain by FDTD simulation. This research is supported by the National Natural Science Foundation of China No. 91230203.
15. Comparison of Gravity Wave Temperature Variances from Ray-Based Spectral Parameterization of Convective Gravity Wave Drag with AIRS Observations
NASA Technical Reports Server (NTRS)
Choi, Hyun-Joo; Chun, Hye-Yeong; Gong, Jie; Wu, Dong L.
2012-01-01
The realism of ray-based spectral parameterization of convective gravity wave drag, which considers the updated moving speed of the convective source and multiple wave propagation directions, is tested against the Atmospheric Infrared Sounder (AIRS) onboard the Aqua satellite. Offline parameterization calculations are performed using the global reanalysis data for January and July 2005, and gravity wave temperature variances (GWTVs) are calculated at z = 2.5 hPa (unfiltered GWTV). AIRS-filtered GWTV, which is directly compared with AIRS, is calculated by applying the AIRS visibility function to the unfiltered GWTV. A comparison between the parameterization calculations and AIRS observations shows that the spatial distribution of the AIRS-filtered GWTV agrees well with that of the AIRS GWTV. However, the magnitude of the AIRS-filtered GWTV is smaller than that of the AIRS GWTV. When an additional cloud top gravity wave momentum flux spectrum with longer horizontal wavelength components that were obtained from the mesoscale simulations is included in the parameterization, both the magnitude and spatial distribution of the AIRS-filtered GWTVs from the parameterization are in good agreement with those of the AIRS GWTVs. The AIRS GWTV can be reproduced reasonably well by the parameterization not only with multiple wave propagation directions but also with two wave propagation directions of 45 degrees (northeast-southwest) and 135 degrees (northwest-southeast), which are optimally chosen for computational efficiency.
16. Optical parametrically gated microscopy in scattering media
PubMed Central
Zhao, Youbo; Adie, Steven G.; Tu, Haohua; Liu, Yuan; Graf, Benedikt W.; Chaney, Eric J.; Marjanovic, Marina; Boppart, Stephen A.
2014-01-01
High-resolution imaging in turbid media has been limited by the intrinsic compromise between the gating efficiency (removal of multiply-scattered light background) and signal strength in the existing optical gating techniques. This leads to shallow depths due to the weak ballistic signal, and/or degraded resolution due to the strong multiply-scattering background – the well-known trade-off between resolution and imaging depth in scattering samples. In this work, we employ a nonlinear optics based optical parametric amplifier (OPA) to address this challenge. We demonstrate that both the imaging depth and the spatial resolution in turbid media can be enhanced simultaneously by the OPA, which provides a high level of signal gain as well as an inherent nonlinear optical gate. This technology shifts the nonlinear interaction to an optical crystal placed in the detection arm (image plane), rather than in the sample, which can be used to exploit the benefits given by the high-order parametric process and the use of an intense laser field. The coherent process makes the OPA potentially useful as a general-purpose optical amplifier applicable to a wide range of optical imaging techniques. PMID:25321724
17. The integration of improved Monte Carlo compton scattering algorithms into the Integrated TIGER Series.
SciTech Connect
Quirk, Thomas, J., IV
2004-08-01
The Integrated TIGER Series (ITS) is a software package that solves coupled electron-photon transport problems. ITS performs analog photon tracking for energies between 1 keV and 1 GeV. Unlike its deterministic counterpart, the Monte Carlo calculations of ITS do not require a memory-intensive meshing of phase space; however, its solutions carry statistical variations. Reducing these variations is heavily dependent on runtime. Monte Carlo simulations must therefore be both physically accurate and computationally efficient. Compton scattering is the dominant photon interaction above 100 keV and below 5-10 MeV, with higher cutoffs occurring in lighter atoms. In its current model of Compton scattering, ITS corrects the differential Klein-Nishina cross sections (which assumes a stationary, free electron) with the incoherent scattering function, a function dependent on both the momentum transfer and the atomic number of the scattering medium. While this technique accounts for binding effects on the scattering angle, it excludes the Doppler broadening the Compton line undergoes because of the momentum distribution in each bound state. To correct for these effects, Ribbefor's relativistic impulse approximation (IA) will be employed to create scattering cross section differential in both energy and angle for each element. Using the parameterizations suggested by Brusa et al., scattered photon energies and angle can be accurately sampled at a high efficiency with minimal physical data. Two-body kinematics then dictates the electron's scattered direction and energy. Finally, the atomic ionization is relaxed via Auger emission or fluorescence. Future work will extend these improvements in incoherent scattering to compounds and to adjoint calculations.
18. Rutherford scattering of electron vortices
Van Boxem, Ruben; Partoens, Bart; Verbeeck, Johan
2014-03-01
By considering a cylindrically symmetric generalization of a plane wave, the first-order Born approximation of screened Coulomb scattering unfolds two new dimensions in the scattering problem: transverse momentum and orbital angular momentum of the incoming beam. In this paper, the elastic Coulomb scattering amplitude is calculated analytically for incoming Bessel beams. This reveals novel features occurring for wide-angle scattering and quantitative insights for small-angle vortex scattering. The result successfully generalizes the well-known Rutherford formula, incorporating transverse and orbital angular momentum into the formalism.
19. Rainbow scattering in nuclear collisions
SciTech Connect
Berezhnoi-breve, Y.A.; Kuznichenko, A.V.; Onishchenko, G.M.; Pilipenko, V.V.
1987-03-01
The evolution of ideas about the rainbow phenomenon resulting from the refraction and reflection of light in water drops is briefly reviewed. The rainbow scattering of particles in quantum mechanics is treated on the basis of the semiclassical approximation, and the nuclear and Coulomb ''rainbows'' are discussed. Rainbow scattering of light ions by nuclei at energies Eapprox. >25--30 MeV/nucleon is considered. The results of theoretical analysis of experimental data on rainbow scattering are presented. The behavior of the nuclear part of the scattering phase shift deduced from experiment is discussed. The manifestation of rainbow scattering in quasielastic nuclear processes is considered. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.756556510925293, "perplexity": 2790.798305536931}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463607636.66/warc/CC-MAIN-20170523122457-20170523142457-00053.warc.gz"} |
http://mathhelpforum.com/differential-geometry/192606-euler-s-method-global-error.html | # Thread: Euler's Method - Global Error
1. ## Euler's Method - Global Error
Use Euler's method with $h = 1/2$ to estimate $y(1)$ for the IVP:
$y(0)=1$
$y'(t)=t^2-y(t)$
Assuming that $|y(t)| \le 1$ for $0 \le t \le 1$ determine the value of n needed to ensure that $|E_n| \le 10^{-2}$
The first part is easy enough:
$y_1=y_0+f(t_0,y_0)h=1+f(0,1)(1/2)=1/2$
$y_2=y_1+f(x_1,y_1)h=1/2-1/8=3/8$
$\Rightarrow y(1)=3/8$
I'm having trouble with the second part. I know I need to use:
$|E_n|\le \frac{T}{L}\left(e^{L(t_n-t_0)}-1\right)$
Could somebody explain to me how I find $L$ and $T$?
2. ## Re: Euler's Method - Global Error
Is this correct for $L$:
$|f(t,u)-f(t,v)|=|t^2-u-t^2+v|=|u-v|$
Lipschitz with $L=1$
3. ## Re: Euler's Method - Global Error
It's $T$ that I'm having trouble with... how would I find the upper bound for $|y''(t)|$? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 18, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8492217063903809, "perplexity": 792.1972012255688}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-48/segments/1386164746201/warc/CC-MAIN-20131204134546-00028-ip-10-33-133-15.ec2.internal.warc.gz"} |
http://trecs.se/ellipse.php | $\newcommand{\sech}{\mathop{\rm sech}\nolimits} \newcommand{\csch}{\mathop{\rm csch}\nolimits} \newcommand{\R}{\mathbb{R}} \newcommand{\basis}{\underline{\mathbf{e}}}$
Current Page
Ellipse
# Ellipse
Object type: Plane curve
### Definition
In $\mathbb{R}^2$, an ellipse $E$ is a set of points $(x, y)$ satisfying the equation $$\left(\frac{x}{a}\right)^2 + \left(\frac{y}{b}\right)^2 = 1$$ for some $a, b > 0$. If $a = b =: r$, then the curve is a circle of radius $r$. Assuming $a > b$, the quantities $a$ and $b$ are called the semimajor and semiminor axis length, respectively. The $x$ and $y$ axes are called the major and minor axes of the ellipse. If $a < b$, the names are reversed accordingly. From now on, we will assume that $x$ is the major axis (that is, $a > b$). In the figure below, $a = 2$ and $b = 1$.
The area enclosed by the ellipse is $A = a b \pi$.
### Parameterisations
This ellipse is a closed curve contained in the rectangle $\left[-a, a\right]\times \left[-b, b\right]$. It can be parameterised by the trigonometric functions. Indeed, the ellipse is the image $E = \mathbf{r}\left(\left[0, 2\pi\right[\right)$ where $$\mathbf{r} \left(t\right) = \underline{\mathbf{e}} \begin{pmatrix}a \cos{t} \\ b \sin{t}\end{pmatrix}, \quad\quad \forall t \in \left[0, 2\pi\right[,$$ as is evident from their definition using the unit circle. In addition, any point $\mathbf{r}\left(t\right)$ clearly satisfies the defining equation of an ellipse because of the trigonometric identity $\sin^2 {t} + \cos^2 {t} = 1$.
The defining equation of the ellipse is equivalent to $y = \pm b\sqrt{1 - x^2/a^2}$. Hence, the upper part ($y \ge 0$) of the ellipse can also be parameterised using $x \in \left[ -a, a\right]$ as parameter by putting $y = b\sqrt{1 - {x^2}/{a^2}}$, or, more explicitly, $$\mathbf{r}\left(t\right) = \underline{\mathbf{e}} \begin{pmatrix}t \\ b\sqrt{1 - {t^2}/ {a^2}}\end{pmatrix}, \quad\quad \forall t \in \left[-a, a\right].$$ In other words, the upper part is the graph of the function $x \mapsto b\sqrt{1 - {x^2}/{a^2}}$. The lower part of the ellipse can be parameterised by putting $y = -b\sqrt{1 - {x^2}/{a^2}}$.
### Curvature
Using the standard (trigonometric) parameterisation, the curvature function for the ellipse is $$\kappa(t) = \frac{ab}{\left(a^2 \sin^2 {t} + b^2 \cos^2 {t}\right)^{3/2}}.$$ In particular, the curvature of a circle of radius $r := a = b$ is $\kappa = 1/r$.
### Eccentricity and Foci
The eccentricity $\epsilon \in \left[0, 1\right[$ of the ellipse is defined as $$\epsilon = \sqrt{1−\frac{b^2}{a^2}}$$ and is (roughly) a measure of the how much a circle needs to be 'flattened' in order to conincide with the ellipse. Indeed, in the case of a circle, $a = b$ and so $\epsilon = 0$; on the other hand, if $a \gg b$, then $b/a \approx 0$ and so $\epsilon \approx 1$.
The two points $$F_1 = -\sqrt{a^2 − b^2} \mathbf{\hat{x}}$$ and $$F_2 = +\sqrt{a^2 − b^2} \mathbf{\hat{x}}$$ are called the foci of the ellipse. Notice that $F_1$ and $F_2$ both lie on the major axis, that $F_1 = -F_2$, and that $|F_1| = |F_2| = \sqrt{a^2−b^2} = a \sqrt{1 − b^2/a^2} = a \epsilon < a$, displaying the fact that both foci lie inside the ellipse. It is straightforward to prove that $$|P − F_1| + |F_2 − P| = 2a \quad \Leftrightarrow \quad P \in E.$$
A corollary of this result is a very easy way of drawing an ellipse using pen and paper. Fix two points on the paper – these will become the foci of the ellipse – and stick two drawing pins at these points. Then attach the ends of a string of length $2a$ to these pins, and hold a pencil against the string in such a way that the string is always fully extended. The curve drawn by the pen as the pen takes all possible positions is an ellipse of semi-major axis $a$.
The distance between any of the foci and the ellipse as measured along a line parallel to the minor axis is called the semi-latus rectum of the ellipse. It is readily verified that the semi-latus rectum is $a(1 - \epsilon^2)$.
### Polar Equation
The polar equation of an ellipse with semi-major axis along the $\varphi = 0$ axis and the right-most focus at the origin is $$r = \frac{a(1-\epsilon^2)}{1 + \epsilon \cos{\varphi}}.$$ We remark that the numerator is the semi-latus rectum of the ellipse.
### Examples
According to Kepler's first law of planetary motion, the orbit of every planet in the solar system is an ellipse with the sun at one of the foci. In fact, in any physical system in which the net force is given by an inverse-square law, the closed orbits are ellipses. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9845107793807983, "perplexity": 102.17373209159668}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257648205.76/warc/CC-MAIN-20180323083246-20180323103246-00275.warc.gz"} |
https://arxiv.org/list/hep-th/1612 | # High Energy Physics - Theory
## Authors and titles for Dec 2016
[ total of 615 entries: 1-25 | 26-50 | 51-75 | 76-100 | ... | 601-615 ]
[ showing 25 entries per page: fewer | more | all ]
[1]
Title: Spinning Kerr black holes with stationary massive scalar clouds: The large-coupling regime
Authors: Shahar Hod
Journal-ref: Journal of High Energy Physics 01, 030 (2017)
Subjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
[2]
Title: How Gaussian can our Universe be?
Comments: 26 + 18 pages, 2 figures. References added and minor typos corrected. Matches published version
Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
[3]
Title: Quantum quenches during inflation
Comments: 30 pages, 10 figures. v2: minor changes and details added. Matches version published in PRD
Journal-ref: Phys. Rev. D 95, 043516 (2017)
Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
[4]
Title: Comment on "AdS nonlinear instability: moving beyond spherical symmetry" [Class. Quantum Grav. 33 23LT01 (2016)]
Comments: 1 page, v2: missing $\theta$ dependence in eqs. (3,4) added
Journal-ref: Class. Quantum Grav. 34 (2017) 128001
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
[5]
Title: On entanglement spreading from holography
Authors: Márk Mezei
Comments: v2: presentation improved, typos fixed, 54 pages, 17 figures v1: 53 pages, 16 figures
Subjects: High Energy Physics - Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el)
[6]
Authors: Bin Chen, Jiang Long
Comments: 29 pages; More discussion on the partition function of primary operators, the contribution from spin-1 operator has been corrected
Journal-ref: Phys. Rev. D 96, 045006 (2017)
Subjects: High Energy Physics - Theory (hep-th)
[7]
Title: Semiholography for heavy ion collisions
Comments: 12 pages; 3 figures; Proceedings of Confinement XII @ Thessaloniki, Greece -- August 28 to September 4, 2016
Subjects: High Energy Physics - Theory (hep-th); High Energy Physics - Phenomenology (hep-ph)
[8]
Title: Understanding the holographic principle via RG flow
Comments: 19 pages; invited review to IJMPA
Journal-ref: International Journal of Modern Physics A Vol. 31, No. 34 (2016) 1630059
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
[9]
Title: Holographic duality and applications
Authors: Yago Bea
Comments: 238 pages, 28 figures. PhD Thesis, Universidade de Santiago de Compostela, Spain (September, 2016). arXiv admin note: substantial text overlap with arXiv:0906.5183 by other authors
Subjects: High Energy Physics - Theory (hep-th)
[10]
Title: Enhanced Asymptotic Symmetry Algebra of 2+1 Dimensional Flat Space
Journal-ref: Phys. Rev. D 95, 046008 (2017)
Subjects: High Energy Physics - Theory (hep-th)
[11]
Title: Supersymmetric $AdS_6$ vacua in six-dimensional $N=(1,1)$ gauged supergravity
Journal-ref: JHEP 01 (2017) 069
Subjects: High Energy Physics - Theory (hep-th)
[12]
Title: BPS Boojums in N=2 supersymmetric gauge theories II
Comments: 75 pages, 29 figures. This paper is a division of arXiv:1603.00447
Subjects: High Energy Physics - Theory (hep-th)
[13]
Title: Geometric interpretation of Planck-scale-deformed co-products
Comments: 9 pages, Contribution to the proceedings of the 9th Alexander Friedmann International Seminar, St. Petersburg, Russia, June 21-27, 2015
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
[14]
Title: Peccei-Quinn Transformations and Black Holes : Orbit Transmutations and Entanglement Generation
Subjects: High Energy Physics - Theory (hep-th); Quantum Physics (quant-ph)
[15]
Title: Stringy bounces and gradient instabilities
Journal-ref: Phys. Rev. D 95, 083506 (2017)
Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
[16]
Title: Irregular Conformal States and Spectral Curve: Irregular Matrix Model Approach
Authors: Chaiho Rim
Journal-ref: SIGMA 13 (2017), 012, 23 pages
Subjects: High Energy Physics - Theory (hep-th); Mathematical Physics (math-ph)
[17]
Title: Simple recipe for holographic Weyl anomaly
Authors: F. Bugini, D. E. Diaz
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); Mathematical Physics (math-ph)
[18]
Title: Black holes in quasi-topological gravity and conformal couplings
Comments: 15 pages, 2 figures. V2: References and a new section on conformally invariant quasitopological gravity added. V3: References and analysis of the unique vacuum case added. V4: References added and typos corrected. To appear in JHEP
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
[19]
Title: Recovering the spacetime metric from a holographic dual
Comments: 16 pages, 5 figures. To appear in the proceedings of the Strings conference, Beijing, August, 2016. v2: typo corrected
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
[20]
Title: New Relations for Gauge-Theory and Gravity Amplitudes at Loop Level
Comments: 6 pages; v2: references added, minor corrections, published version with updated reference on work in progress
Journal-ref: Phys. Rev. Lett. 118, 161601 (2017)
Subjects: High Energy Physics - Theory (hep-th)
[21]
Title: Factorization of differential expansion for non-rectangular representations
Authors: A. Morozov
Journal-ref: MPLA 33 No. 12 (2018) 1850062
Subjects: High Energy Physics - Theory (hep-th); Mathematical Physics (math-ph); Geometric Topology (math.GT); Quantum Algebra (math.QA)
[22]
Title: DBI from Gravity
Subjects: High Energy Physics - Theory (hep-th)
[23]
Journal-ref: JHEP 1703 (2017) 118
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); Quantum Physics (quant-ph)
[24]
Title: A Universe Without Dark Energy: Cosmic Acceleration from Dark Matter-Baryon Interactions | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.49441054463386536, "perplexity": 8453.758716550568}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376824675.15/warc/CC-MAIN-20181213101934-20181213123434-00267.warc.gz"} |
https://zims-en.kiwix.campusafrica.gos.orange.com/wikipedia_en_all_nopic/A/Equivalent_air_depth | # Equivalent air depth
The equivalent air depth (EAD) is a way of approximating the decompression requirements of breathing gas mixtures that contain nitrogen and oxygen in different proportions to those in air, known as nitrox.[1][2][3]
The equivalent air depth, for a given nitrox mix and depth, is the depth of a dive when breathing air that would have the same partial pressure of nitrogen. So, for example, a gas mix containing 36% oxygen (EAN36) being used at 27 metres (89 ft) has an EAD of 20 metres (66 ft).
## Calculations in metres
The equivalent air depth can be calculated for depths in metres as follows:
EAD = (Depth + 10) × Fraction of N2 / 0.79 10
Working the earlier example, for a nitrox mix containing 64% nitrogen (EAN36) being used at 27 metres, the EAD is:
EAD = (27 + 10) × 0.64 / 0.79 10
EAD = 37 × 0.81 10
So at 27 metres on this mix, the diver would calculate their decompression requirements as if on air at 20 metres.
## Calculations in feet
The equivalent air depth can be calculated for depths in feet as follows:
EAD = (Depth + 33) × Fraction of N2 / 0.79 33
Working the earlier example, for a nitrox mix containing 64% nitrogen (EAN36) being used at 90 feet, the EAD is:
EAD = (90 + 33) × 0.64 / 0.79 33
EAD = 123 × 0.81 33
So at 90 feet on this mix, the diver would calculate their decompression requirements as if on air at 67 feet.
## Derivation of the formulas
For a given nitrox mixture and a given depth, the equivalent air depth expresses the theoretical depth that would produce the same partial pressure of nitrogen if regular air (79% nitrogen) was used instead:
${\displaystyle ppN_{2}(nitrox,depth)=ppN_{2}(air,EAD)}$
Hence, following the definition of partial pressure:
${\displaystyle FN_{2}(nitrox)\cdot P_{depth}=FN_{2}(air)\cdot P_{EAD}}$
with ${\displaystyle FN_{2}}$ expressing the fraction of nitrogen and ${\displaystyle P_{depth}}$ expressing the pressure at the given depth. Solving for ${\displaystyle P_{EAD}}$ then yields a general formula:
${\displaystyle P_{EAD}={FN_{2}(nitrox) \over FN_{2}(air)}\cdot P_{depth}}$
In this formula, ${\displaystyle P_{EAD}\,}$ and ${\displaystyle P_{depth}\,}$ are absolute pressures. In practice, it is much more convenient to work with the equivalent columns of seawater depth, because the depth can be read off directly from the depth gauge or dive computer. The relationship between pressure and depth is governed by Pascal's law:
${\displaystyle P_{depth}=P_{atmosphere}+\rho _{seawater}\cdot g\cdot h_{depth}\,}$
Using the SI system with pressures expressed in pascal, we have:
${\displaystyle P_{depth}(Pa)=P_{atmosphere}(Pa)+\rho _{seawater}\cdot g\cdot h_{depth}(m)\,}$
Expressing the pressures in atmospheres yields a convenient formula (1 atm ≡ 101325 Pa):
${\displaystyle P_{depth}(atm)=1+{\frac {\rho _{seawater}\cdot g\cdot h_{depth}}{P_{atmosphere}(Pa)}}=1+{\frac {1027\cdot 9.8\cdot h_{depth}}{101325}}\ \approx 1+{\frac {h_{depth}(m)}{10}}}$
To simplify the algebra we will define ${\displaystyle {\frac {FN_{2}(nitrox)}{FN_{2}(air)}}=R}$. Combining the general formula and Pascal's law, we have:
${\displaystyle 1+{\frac {h_{EAD}}{10}}=R\cdot (1+{\frac {h_{depth}}{10}})}$
so that
${\displaystyle h_{EAD}=10\cdot (R+R\cdot {\frac {h_{depth}}{10}}-1)=R\cdot (h_{depth}+10)-10}$
Since ${\displaystyle h(ft)\approx 3.3\cdot h(m)\,}$, the equivalent formula for the imperial system becomes
${\displaystyle h_{EAD}(ft)=3.3\cdot {\Bigl (}R\cdot ({\frac {h_{depth}(ft)}{3.3}}+10)-10{\Bigr )}=R\cdot (h_{depth}(ft)+33)-33}$
Substituting R again, and noting that ${\displaystyle FN_{2}(air)=0.79}$, we have the concrete formulas:
${\displaystyle h_{EAD}(m)={\frac {FN_{2}(nitrox)}{0.79}}\cdot (h_{depth}(m)+10)-10}$
${\displaystyle h_{EAD}(ft)={\frac {FN_{2}(nitrox)}{0.79}}\cdot (h_{depth}(ft)+33)-33}$
## Dive tables
Although not all dive tables are recommended for use in this way, the Bühlmann tables are suitable for use with these kind of calculations. At 27 metres the Bühlmann 1986 table (0700 m) allows 20 minutes bottom time without requiring a decompression stop. While at 20 metres the no-stop time is 35 minutes. This shows that using EAN36 for a 27-metre dive can give a 75% increase in bottom time over using air.
US Navy tables have also been used with equivalent air depth, with similar effect. The calculations are theoretically valid for all Haldanean decompression models.
## References
1. Logan, JA (1961). "An evaluation of the equivalent air depth theory". United States Navy Experimental Diving Unit Technical Report. NEDU-RR-01-61. Retrieved 2008-05-01.
2. Berghage Thomas E, McCraken TM (December 1979). "Equivalent air depth: fact or fiction". Undersea Biomedical Research. 6 (4): 379–84. PMID 538866. Retrieved 2008-05-01.
3. Lang, Michael A. (2001). DAN Nitrox Workshop Proceedings. Durham, NC: Divers Alert Network. p. 197. Retrieved 2008-05-02. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 19, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9283500909805298, "perplexity": 3346.0527011720465}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593655890566.2/warc/CC-MAIN-20200706222442-20200707012442-00296.warc.gz"} |
https://www.aimsciences.org/article/doi/10.3934/dcds.2009.25.585 | # American Institute of Mathematical Sciences
July 2009, 25(2): 585-615. doi: 10.3934/dcds.2009.25.585
## Modeling solutions with jumps for rate-independent systems on metric spaces
1 Weierstraß-Institut, Mohrenstraße 39, 10117 D–Berlin, Germany 2 Dipartimento di Matematica, Università di Brescia, Via Valotti 9, I–25133 Brescia, Italy 3 Dipartimento di Matematica “F. Casorati”, Università di Pavia, Via Ferrata 1, I–27100 Pavia, Italy
Received July 2008 Revised January 2009 Published June 2009
Rate-independent systems allow for solutions with jumps that need additional modeling. Here we suggest a formulation that arises as limit of viscous regularization of the solutions in the extended state space. Hence, our parametrized metric solutions of a rate-independent system are absolutely continuous mappings from a parameter interval into the extended state space. Jumps appear as generalized gradient flows during which the time is constant. The closely related notion of BV solutions is developed afterwards. Our approach is based on the abstract theory of gradient flows in metric spaces, and comparison with other notions of solutions is given.
Citation: Alexander Mielke, Riccarda Rossi, Giuseppe Savaré. Modeling solutions with jumps for rate-independent systems on metric spaces. Discrete & Continuous Dynamical Systems - A, 2009, 25 (2) : 585-615. doi: 10.3934/dcds.2009.25.585
[1] Augusto Visintin. Structural stability of rate-independent nonpotential flows. Discrete & Continuous Dynamical Systems - S, 2013, 6 (1) : 257-275. doi: 10.3934/dcdss.2013.6.257 [2] Gianni Dal Maso, Alexander Mielke, Ulisse Stefanelli. Preface: Rate-independent evolutions. Discrete & Continuous Dynamical Systems - S, 2013, 6 (1) : i-ii. doi: 10.3934/dcdss.2013.6.1i [3] T. J. Sullivan, M. Koslowski, F. Theil, Michael Ortiz. Thermalization of rate-independent processes by entropic regularization. Discrete & Continuous Dynamical Systems - S, 2013, 6 (1) : 215-233. doi: 10.3934/dcdss.2013.6.215 [4] Riccarda Rossi, Giuseppe Savaré. A characterization of energetic and $BV$ solutions to one-dimensional rate-independent systems. Discrete & Continuous Dynamical Systems - S, 2013, 6 (1) : 167-191. doi: 10.3934/dcdss.2013.6.167 [5] Sylvia Serfaty. Gamma-convergence of gradient flows on Hilbert and metric spaces and applications. Discrete & Continuous Dynamical Systems - A, 2011, 31 (4) : 1427-1451. doi: 10.3934/dcds.2011.31.1427 [6] Daniele Davino, Ciro Visone. Rate-independent memory in magneto-elastic materials. Discrete & Continuous Dynamical Systems - S, 2015, 8 (4) : 649-691. doi: 10.3934/dcdss.2015.8.649 [7] Ulisse Stefanelli, Daniel Wachsmuth, Gerd Wachsmuth. Optimal control of a rate-independent evolution equation via viscous regularization. Discrete & Continuous Dynamical Systems - S, 2017, 10 (6) : 1467-1485. doi: 10.3934/dcdss.2017076 [8] Martin Heida, Alexander Mielke. Averaging of time-periodic dissipation potentials in rate-independent processes. Discrete & Continuous Dynamical Systems - S, 2017, 10 (6) : 1303-1327. doi: 10.3934/dcdss.2017070 [9] Michela Eleuteri, Luca Lussardi, Ulisse Stefanelli. A rate-independent model for permanent inelastic effects in shape memory materials. Networks & Heterogeneous Media, 2011, 6 (1) : 145-165. doi: 10.3934/nhm.2011.6.145 [10] Stefano Bosia, Michela Eleuteri, Elisabetta Rocca, Enrico Valdinoci. Preface: Special issue on rate-independent evolutions and hysteresis modelling. Discrete & Continuous Dynamical Systems - S, 2015, 8 (4) : i-i. doi: 10.3934/dcdss.2015.8.4i [11] Jaeyoo Choy, Hahng-Yun Chu. On the dynamics of flows on compact metric spaces. Communications on Pure & Applied Analysis, 2010, 9 (1) : 103-108. doi: 10.3934/cpaa.2010.9.103 [12] Luca Minotti. Visco-Energetic solutions to one-dimensional rate-independent problems. Discrete & Continuous Dynamical Systems - A, 2017, 37 (11) : 5883-5912. doi: 10.3934/dcds.2017256 [13] Alice Fiaschi. Rate-independent phase transitions in elastic materials: A Young-measure approach. Networks & Heterogeneous Media, 2010, 5 (2) : 257-298. doi: 10.3934/nhm.2010.5.257 [14] Martin Kružík, Johannes Zimmer. Rate-independent processes with linear growth energies and time-dependent boundary conditions. Discrete & Continuous Dynamical Systems - S, 2012, 5 (3) : 591-604. doi: 10.3934/dcdss.2012.5.591 [15] Michela Eleuteri, Luca Lussardi. Thermal control of a rate-independent model for permanent inelastic effects in shape memory materials. Evolution Equations & Control Theory, 2014, 3 (3) : 411-427. doi: 10.3934/eect.2014.3.411 [16] Oleksiy V. Kapustyan, Pavlo O. Kasyanov, José Valero, Michael Z. Zgurovsky. Strong attractors for vanishing viscosity approximations of non-Newtonian suspension flows. Discrete & Continuous Dynamical Systems - B, 2018, 23 (3) : 1155-1176. doi: 10.3934/dcdsb.2018146 [17] Martin Brokate, Pavel Krejčí. Optimal control of ODE systems involving a rate independent variational inequality. Discrete & Continuous Dynamical Systems - B, 2013, 18 (2) : 331-348. doi: 10.3934/dcdsb.2013.18.331 [18] Stefano Bianchini, Alberto Bressan. A case study in vanishing viscosity. Discrete & Continuous Dynamical Systems - A, 2001, 7 (3) : 449-476. doi: 10.3934/dcds.2001.7.449 [19] Umberto Mosco, Maria Agostina Vivaldi. Vanishing viscosity for fractal sets. Discrete & Continuous Dynamical Systems - A, 2010, 28 (3) : 1207-1235. doi: 10.3934/dcds.2010.28.1207 [20] Alexander J. Zaslavski. Stability of a turnpike phenomenon for a class of optimal control systems in metric spaces. Numerical Algebra, Control & Optimization, 2011, 1 (2) : 245-260. doi: 10.3934/naco.2011.1.245
2018 Impact Factor: 1.143 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6368693709373474, "perplexity": 7562.736110599124}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570987834649.58/warc/CC-MAIN-20191023150047-20191023173547-00205.warc.gz"} |
https://gamedev.stackexchange.com/questions/103246/generate-box2d-bodies-from-isometric-tiled-map | # generate box2d bodies from isometric tiled map
I followed the tutorial here to generate box2d bodies from a tiled map and that worked fine.... for orthogonal tiled maps. Unfortunately isometric maps use their own coordinate system where (0, 0) is at the leftmost corner of the map, and this causes the bodies to be in the wrong place.
I tried implementing a transformation matrix or just transforming the body but I don't think that is possible (or at least I could never find a way). How else can this be solved? Here is the relevant method that needs to be changed:
private Shape getPolygon(PolygonMapObject polygonObject) {
PolygonShape polygon = new PolygonShape();
float[] vertices = polygonObject.getPolygon().getTransformedVertices();
float[] worldVertices = new float[vertices.length];
for (int i = 0; i < vertices.length; ++i) {
worldVertices[i] = vertices[i] / units;
}
polygon.set(worldVertices);
return polygon;
}
As you can see I need a way to convert the isometric coordinates to game coordinates using just plain math or something else like a matrix. I think the only line needing to be changed is the line in the for loop.
• did you ever solve it? I'm having the same issue – Lior Iluz Apr 27 '16 at 10:12
• Did you ever end up fixing this? – Troy Dickie Apr 6 '17 at 6:28
• Yes I did end up solving I think. I can't remember how because I ended up converting my app to 3D because it made things much easier, but I will look through my old code and see if I can find the solution – Vincent Williams Apr 7 '17 at 17:01
I had the same question that I have been able to answer here Box2d collision on isometric maps built in Tiled
Get the vertices out of the polygon and transform them from orthographic space to isometric with code like this.
public static Vector2 TwoDToIso(Vector2 point){
Vector2 vel2 = new Vector2();
vel2.x = point.x - point.y;
vel2.y = -(point.x + point.y) / 2;
return vel2;
}
I had to minus the y value in my example because my object was flipped incorrectly.
I hope this helps | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.20673583447933197, "perplexity": 1391.5851715288127}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046150134.86/warc/CC-MAIN-20210724063259-20210724093259-00080.warc.gz"} |
https://api.philpapers.org/browse/derrida-philosophy-of-religion | This category needs an editor. We encourage you to help if you are qualified.
# Derrida: Philosophy of Religion
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1. Printing Religion after the Enlightenment.Timothy Stanley - 2022 - Lanham: Lexington Books | Rowman and Littlefield Publishers.
Over the course of the seventeenth to eighteenth centuries, an interior private notion of religion gained wide public recognition. It then spread through settler colonial contexts around the world. It has since been criticized for its abstract, immaterial nature as well as its irrelevance to traditions beyond the European context. However, such critiques obscure the contradiction between religion’s definition as a matter of interior privacy and its public visibility in various printed publications. Firstly, this monograph responds by re-evaluating the cultural (...)
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2. The Religion (without Religion) of the Living (without Life): Re-reading Derrida’s “Faith and Knowledge”.King-Ho Leung - 2021 - Eidos. A Journal for Philosophy of Culture 5 (3):35-49.
This article offers a reading of Jacques Derrida’s account of “religion” and “life” in his seminal essay “Faith and Knowledge.” Applying Derrida’s aporetic structure of “X without X” to his remarks on religion and life in “Faith and Knowledge,” this article suggests that underlying Derrida’s endeavor to “think religion abstractly” is a radical re-conception not only of religion as “religion without religion” but moreover a re-imagination of life as “life without life” that breaks away from the traditional metaphysical understandings of (...)
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3. This is an essay on Kant's neglected late tract On a Recently Adopted Prominent Tone in Philosophy (RTP) and Derrida's oblique commentary on this work in his D'un ton apocalyptique adopté naguère en philosophie. The theme of the essay is metaphilosophical and considers issues concerning the nature of critical philosophy, fanaticism (Schwärmerei), and the use of religious tropes in philosophy. I am primarily interested in the ways in which RTP thematises the legitimacy of speaking in an exalted, quasi-religious tone apropos (...)
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4. Wittgenstein's Ladder - Political Theology.Mehmet Karabela - 2019 - Political Theology Network.
…I see my list on political theology functioning like Wittgenstein’s ladder metaphor in his Tractatus. Once graduate students read and grasp these important texts, they should “throw away the ladder”, so to speak, and deconstruct all they have learned about political theology to illuminate contemporary problems on their own. Once they reach the top, they can throw away the ladder.
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5. Kenotic Chorology as A/theology in Nishida and beyond.John W. M. Krummel - 2019 - Sophia 58 (2):255-282.
In this paper, I explore a possible a/theological response to what Nietzsche called the ‘death of God’—or Hölderlin’s and Heidegger’s ‘flight of the gods’—through a juxtaposition of the Christian-Pauline concept of kenōsis and the ancient Greek-Platonic notion of chōra, and by taking Nishida Kitarō’s appropriations of these concepts as a clue and starting point. Nishida refers to chōra in 1926 to initiate his philosophy of place and then makes reference to kenōsis in 1945 in his final work that culminates—without necessarily (...)
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6. Pensées Magiques: Retour sur le 'Retour du Religieux'.Thomas Clément Mercier - 2019 - Revue ITER 1.
Dans cet essai, j'analyse les présuppositions du récit dudit « retour du religieux », du point de vue de la psychanalyse (Freud) et de la déconstruction (Derrida). Après avoir mis à jour l'eurocentrisme et le colonialisme inhérents aux concepts de « magie », « animisme », « religion » et « croyance » chez Freud (avec une attention particulière portée à Totem et tabou), j’offre une lecture déconstructrice des discours politiques contemporains sur le sécularisme, la foi et le savoir.
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7. Review of Ethics and Culture: Some Contemporary Indian Reflections Vol. 2. [REVIEW]Subhasis Chattopadhyay - 2017 - Prabuddha Bharata or Awakened India 122 (5):480.
The reviewer finds the much obfuscated (sic) logos explained in this gem of an anthology. The reviewer picks up the notion of the logos and his review turns around this philosophical stonewall. The genius of one of the contributors is in connecting logos to the Tao.
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8. Writing Faith.Timothy Stanley - 2017 - Minneapolis: Fortress Press.
This book provides a novel reevaluation of Jacques Derrida’s deconstructive account of writing. Derrida’s various essays on writing's materiality in books, scrolls, typewriters and digital displays, briefly touched on the question of religion. At times he directed his attention to the mediatic nature of Christianity. However, such comments have rarely been applied to formal aspects of religious texts. In response, this book investigates the rise of the Christian codex in its second-to-fifth-century-CE Jewish and Greco-Roman contexts. By better understanding the religious (...)
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9. Eckhart, Derrida, and The Gift of Love.David Newheiser - 2015 - Heythrop Journal 56 (6):1010-1021.
This paper argues that Jacques Derrida and Meister Eckhart both construe love as a gift that is entirely free of economic exchange, and both conclude on this basis that love cannot be grasped or identified. In my reading, Eckhart and Derrida do not rule out consideration of one’s own well-being, but their accounts do entail that calculated self-protection is external to love. For this reason, they suggest, lovers should not expect to balance love against a prudential restraint: although both demands (...)
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10. The Wonder and Spirit of Phenomenology and Theology: Rubenstein and Derrida on Heidegger's Formal Distinction of Philosophy from Theology.Peter Capretto - 2014 - Heythrop Journal 55 (4):599-611.
While Heidegger's earlier phenomenological writings inform much contemporary discourse in the continental philosophy of religion, his 1927 essay on ‘Phenomenology and Theology’ offers a largely uncontested distinction between philosophy and theology on the basis of their possibilities as sciences following ontological difference. This paper reconsiders Heidegger's distinction by invoking spirit and wonder, concepts Jacques Derrida and Mary-Jane Rubenstein have more recently emphasized as central to thought that is open to that which ruptures metaphysical schemas. I contend Heidegger's use of ontological (...)
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11. Kantian Transpositions: Derrida and the Philosophy of Religion.Eddis N. Miller - 2014 - Evanston, Illinois: Northwestern University Press.
Kantian Transpositions presents an important new reading of Jacques Derrida’s writings on religion and ethics. Eddis Miller argues that Derrida’s late texts on religion constitute an interrogation of the meaning and possibility of a “philosophy of religion.” It is the first book to fully engage Derrida’s claim, in “Faith and Knowledge: The Two Sources of ‘Religion’ at the Limits of Reason Alone” to be transposing the Kantian gesture of thinking religion “within the limits of reason alone.” Miller outlines the terms (...)
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12. Embodied Disbelief: Poststructural Feminist Atheism.Donovan O. Schaefer - 2014 - Hypatia 29 (2):371-387.
“I quite rightly pass for an atheist,” Jacques Derrida announces in Circumfession. Grace Jantzen's suggestion that the poststructuralist critique of modernity can also be trained on atheism helps us make sense of this playfully cryptic statement: although Derrida sympathizes with the “idea” of atheism, he is wary of the modern brand of atheism, with its insistence on rationally arranging—straightening out—religion. In this paper, I will argue that poststructural feminism, with its focus on embodied epistemology, offers a way to re-explain Derrida's (...)
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13. Of Globalatinology.Gil Anidjar - 2013 - Derrida Today 6 (1):11-22.
Have we ever been religious? It may seem strange to open an essay on Derrida with a Latourean question. Yet, with regard to religion, what Derrida demonstrates is quite unavoidably this: we have long been, and are still being, Christianized. Whatever else we may have been, perhaps still are, constitutes but the space or espacement offered or relinquished, however reluctantly or even grudgingly (though more often than not quite willingly) to Christianization. This is a space that goes beyond whatever is (...)
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14. Preface The ‘Deconstruction of Christianity’: A Special Issue.Gary Banham - 2013 - Derrida Today 6 (1):1-10.
The theme of the ‘deconstruction of Christianity’, which was selected for this special issue of Derrida Today, is one that arises not from the work of Derrida himself in the first instance but instead from that of Jean-L Nancy. Not only is this so but Derrida's ([2000] 2005) own view of the notion of the ‘deconstruction of Christianity’ seems, on the evidence available, to be at least open to quite a bit of interpretation given the ambiguous nature of some of (...)
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15. Touching the Opening of the World.Gary Banham - 2013 - Derrida Today 6 (1):58-77.
In this article I seek to address the way that Jean-Luc Nancy's project of the ‘deconstruction of Christianity’ relates to the understanding of what might be meant by ‘Christian art’. In the process of looking at Nancy's treatment of some signal ‘Christian’ scenes I describe some ways in which the motif of ‘touching’ arises as significant for how Nancy addresses the possibility of ‘alienation from the world’, a possibility that he takes to be central to the self-deconstructive potential of ‘Christianity’. (...)
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16. Surviving Christianity.Clayton Crockett - 2013 - Derrida Today 6 (1):23-35.
In his essay ‘The Deconstruction of Christianity’, Jean-Luc Nancy identifies Christianity with the heart of the West, thus following René Girard's claim that Christianity is the religion that exposes the workings of scapegoating and mimetic violence that drive most religions and cultures. However, in On Touching, Derrida distances himself from Nancy's project, and I argue that this is precisely because he is aware that a straightforward embrace of the deconstruction of Christianity is a ruse, as it will end up in (...)
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17. Between the canon and the Messiah: the structure of faith in contemporary Continental thought.Colby Dickinson - 2013 - New York: Bloomsbury Academic.
The legacy of an antinomian messianism within a Jewish historical context -- Jacques Derrida and Giorgio Agamben on the processes of messianicity and canonicity -- Conclusions formulated on the basis of part I: recognizing the challenges of a "political theology of immanence" -- The radical hermeneutics of theology -- The "violence" of the canon: a contemporary context for the canonical form -- The necessity of hermeneutics.
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18. Seeing the World and Knowing God: Hebrew Wisdom and Christian Doctrine in a Late-Modern Context.Paul S. Fiddes - 2013 - Oxford University Press.
This creates a Christian theology of wisdom for the present day, in discussion with two sets of conversation-partners: The writers of the 'wisdom literature' in ancient Israel and the Jewish community in Alexandria; and the philosophers and thinkers of the late-modern age, among them Derrida, Levinas, Kristeva, Ricoeur, and Arendt.
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19. Postmetaphysics in this book is interpreted as thinking through metaphysics at the closure of metaphysics by thinking the impossible possibility of metaphysics. In this site of the closure of metaphysics and the turn to language, the grammar of faith is discovered as the grammar of language or writing. The logic or grammatology of writing and thus of reality is revealed, not contra to philosophy or metaphysics, but when thinking through metaphysics to its end or closure, and there in that site (...)
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20. Derrida, Jacques. I. Derrida and Jewishness.D. Newheiser - 2013 - In D. Allison, V. Leppin, C. Seow, H. Spieckermann, B. D. Walfish & E. Ziolkowski (eds.), The Encyclopedia of the Bible and its Reception, Volume 6. Berlin: Walter de Gruyter.
Dictionary entry on Jacques Derrida's relation to Judaism.
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21. The Word Became Machine: Derrida's Technology of Incarnation.Steven Shakespeare - 2013 - Derrida Today 6 (1):36-57.
For Derrida, the technological, automatic and mechanical could never simply be defined as external or opposed to the voluntary, conscious and spiritual. The articulation and repeatability of the trace means that there is something machinic that is inseparable from the possibilities of meaning, choice and faith. This paper will draw on various texts – including ‘Faith and Knowledge’, Without Alibi and On Touching – to explore the mutual unravelling of machine and flesh in the Christian doctrine of the incarnation. It (...)
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22. Shallow Graves: Toward a Philosophical Comedy of Tears Over the Serial Dying of Gods.Yvonne Sherwood & Ward Blanton - 2013 - Derrida Today 6 (1):78-96.
Recent debates about the legacy (and, sometimes, surpassing) of Derridean philosophy have often oriented themselves around questions of a new austerity in relation to the implicit philosophical functioning of God. Indeed, an increasing philosophical vigilance about the death or nonexistence of God has begun to be presented as a hallmark of recent criticisms of earlier receptions of Derrida and, by way of messianic structures of time, of Derridean politics as well. We argue that the inflating value of atheism in recent (...)
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23. Donner la mort? Phénoménologie et sacrifice Note sur une interprétation de Derrida.Dan Arbib - 2012 - Studia Phaenomenologica 12:383-397.
This article claims to dispute Derrida’s interpretation of Isaac’s sacrifice proposed in Donner la mort by means of three sources: 1) midrashic sources, which impose to read the sacrifice not as a requirement of murder, but as sacrifice of the sacrifice; 2) the phenomenology of Levinas which allows to measure the violence of the interpretation of Derrida and to return the biblical episode to the complications of the relationships between ethics and rationality; 3) the phenomenology of Marion, which, by refusing (...)
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24. The End of Comparative Philosophy and the Task of Comparative Thinking: Heidegger, Derrida, and Daoism. By Steven Burik.Jay Goulding - 2012 - Journal of Chinese Philosophy 39 (2):317-320.
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25. Science and transcendence: Westphal, Derrida, and responsibility.Nathan Kowalsky - 2012 - Zygon 47 (1):118-139.
Abstract. On the naive reading, “radical social constructivism” would be the result of “deconstructing” science. Science would simply be a contingent construction in accordance with social determinants. However, postmodernism does not necessarily abandon fidelity to the objects of thought. Merold Westphal's Derridean philosophy of religion emphasizes that even theology need not eliminate the transcendence of the divine other. By drawing an analogy between natural and supernatural transcendence, I argue that science is similarly called to responsibility in the encounter with that (...)
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26. Democracia y mesianicidad : consideraciones en torno a lo político en el pensamiento de Derrida.Laura Llevadot - 2012 - Enrahonar: Quaderns de Filosofía 48:95-109.
El objetivo de este trabajo es demostrar que aquello que vincula la deconstrucción con lo político es la idea de acontecimiento y, en concreto, la fe en el acontecimiento. Lo mesiánico consiste en esta fe en el acontecimiento que Derrida recupera de Marx. Para demostrar esta tesis procederé, en primer lugar, a distinguir la idea de mesianicidad de la idea reguladora kantiana; en segundo lugar, se analizará el concepto de creencia que, según Derrida, debe habitar el concepto mismo de democracia; (...)
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27. Miracle and Machine: Jacques Derrida and the Two Sources of Religion, Science, and the Media.Michael Naas - 2012 - Fordham University Press.
Miracle and Machine is a sort of "reader's guide" to Jacques Derrida's 1994 essay "faith and knowledge," his most important work on the nature of religion in general and on the unprecedented forms it is taking today through science and the ...
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28. The philosophy and literature of the death penalty: Two sides of the same sovereign.Michael Naas - 2012 - Southern Journal of Philosophy 50 (s1):39-55.
This essay demonstrates that in his 1999–2000 Death Penalty Seminar Jacques Derrida pursues the deconstruction of political theology that he had been pursuing in a more or less explicit fashion for more than two decades. Derrida's interest in the theme of the death penalty can be traced back in large part, it is argued, to the theological and essentially Judeo-Christian origins that Derrida finds in discourses both for and against the death penalty. This emphasis on the theological origins of the (...)
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29. The Young Derrida and French Philosophy, 1945–1968.Edward Baring - 2011 - Cambridge University Press.
Machine generated contents note: Introduction; Part I. Derrida Post-Existentialist: 1. Humanist pretensions: Catholics, Communists and Sartre's struggle for existentialism in post-war France; 2. Derrida's 'Christian' existentialism; 3. Normalization: the École Normale Supe;rieure and Derrida's turn to Husserl; 4. Genesis as a problem: Derrida reading Husserl; 5. The God of mathematics: Derrida and the origin of geometry; Part II. Between Phenomenology and Structuralism: 6. A history of diffe;rance; 7. L'ambiguite; du concours: the deconstruction of commentary and interpretation in Speech and Phenomena; (...)
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30. Der „religiöse“ Charakter von Heideggers philosophischer Methode: relegere, re-eligere, relinquere.Vincent Blok - 2011 - Studia Phaenomenologica 11:285-307.
The question addressed in this article is to what extent a destructed concept of religion can be said to characterize the philosophical method of Martin Heidegger. In order to approach this question, we first characterize his method as “Vollzug der Fraglichkeit”: philosophy in its deepest sense does not mean to give answers to questions but to ask questions. According to Heidegger, the execution of questioning consists in the “transforming repetition” of the leading question of philosophy in order to ask the (...)
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31. For Derrida, the ‘‘as if’’, as a regulative principle directly appropriated and modified from its Kantian context, becomes the central lynchpin for understanding, not only Derrida's philosophical system as a whole, but also his numerous seemingly enigmatic references to his ‘‘jewishness’’. Through an analysis of the function of the ‘‘as if’’ within the history of thought, from Greek tragedy to the poetry of Wallace Stevens, I hope to show how Derrida can only appropriate his Judaic roots as an act of (...)
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32. Radical Atheism: Derrida and the Time of Life.Adam Kelly - 2011 - International Journal of Philosophical Studies 19 (5):761 - 768.
International Journal of Philosophical Studies, Volume 19, Issue 5, Page 761-768, December 2011.
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33. Remove from this list
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34. Learning to live up to death -- finally: Ricoeur and Derrida on the textuality of immortality.B. Keith Putt - 2011 - Philosophy and Social Criticism 37 (2):239-247.
In the ninth fragment of his posthumous work Living Up to Death , Paul Ricoeur reflects on Jacques Derrida’s final interview given to the French newspaper Le Monde just months prior to his death. Although he confesses to a genuine distanciation from Derrida regarding salient aspects of their individual memento mori , he does so within the context of significant concessions of agreement. I argue in this article that their differing positions de facto agree at a critical structural level with (...)
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35. Economy of "invisible debt" and ethics of "radical hospitality": Toward a paradigm change of hospitality from "gift" to "forgiveness".Ilsup Ahn - 2010 - Journal of Religious Ethics 38 (2):243-267.
The purpose of this paper is to reconstruct a Christian theology of “hospitality” through a critical reading of Jacques Derrida and Friedrich Nietzsche as well as through an in-depth biblical and theological reflection on the ethics of hospitality. Out of this reconstructive investigation, I propose a new Christian ethics of hospitality as a radical kind. As a new paradigm, this radical hospitality is distinguished from other types in that it is no longer conceived on the model of “gift”. The new (...)
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36. The genealogy of debt and the phenomenology of forgiveness: Nietzsche, Marion, and Derrida on the meaning of the peculiar phenomenon.Ilsup Ahn - 2010 - Heythrop Journal 51 (3):454-470.
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37. Thinking on the edge: Heidegger, Derrida, and the daoist gateway ( men 門).Steven Burik - 2010 - Philosophy East and West 60 (4):499-516.
Beware of the abysses and the gorges, but also of the bridges and the barriers.It is fair to say that many philosophical interpretations of the Daoist classics have proceeded, or continue to proceed, to read into these works the quest for a transcendental, foundational principle, a permanent moment of rest beyond the turmoil of ever-changing things. According to this interpretation the Daoist sages are those who have for all time found this metaphysical ground of all things—"The Way" (dao 道)—and who (...)
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38. Islam and the West: A Conversation with Jacques Derrida , by Mustapha Chérif. [REVIEW]David Frost - 2010 - Philosophical Papers 39 (2):271-279.
Originally published as L'Islam et l'occident, 2006. Translated by Teresa Lavender Fagan. Chicago: University of Chicago Press, 2008. xxii + 114 pp. Hardback, $19.99. Remove from this list Direct download (3 more) Export citation Bookmark 39. Negative Theology and Conversion: Derrida's Neoplatonic Compulsions.Stephen Gersh - 2010 - In Miriam Leonard (ed.), Derrida and Antiquity. Oxford University Press. pp. 101. Remove from this list Export citation Bookmark 40. Review of Steven Shakespeare, Derrida and Theology[REVIEW]Sarah Hammerschlag - 2010 - Notre Dame Philosophical Reviews 2010 (8). Remove from this list Direct download Export citation Bookmark 41. The Figural Jew: Politics and Identity in Postwar French Thought.Sarah Hammerschlag - 2010 - University of Chicago Press. Introduction -- Roots, rootlessness, and fin de siècle France -- Stranger and self: Sartre's Jew -- Anti-Semite and Jew -- Dialectical history, unhappy consciousness, and the Messiah -- The ethics of uprootedness: Emmanuel Levinas's postwar project -- Literary unrest: Maurice Blanchot's rewriting of Levinas --"The Last of the Jews": Jacques Derrida and the case of the figure -- The cut -- The exemplar -- Conclusion. Remove from this list Direct download Export citation Bookmark 6 citations 42. Returning (to) the gift of death: violence and history in Derrida and Levinas.Jeffrey Hanson - 2010 - International Journal for Philosophy of Religion 67 (1):1 - 15. The purpose of this paper is to establish a proper context for reading Jacques Derrida's The Gift of Death, which, I contend, can only be understood fully against the backdrop of "Violence and Metaphysics." The later work cannot be fully understood unless the reader appreciates the fact that Derrida returns to "a certain Abraham" not only in the name of Kierkegaard but also in the name of Levinas himself. The hypothesis of the reading that follows therefore would be that Derrida (...) Remove from this list Direct download (4 more) Export citation Bookmark 1 citation 43. John Llewelyn: Margins of religion: between Kierkegaard and Derrida: Indiana University Press, Bloomington, IN, 2009, xiv + 470 pp,$85 , \$34.95. [REVIEW]Patricia Altenbernd Johnson - 2010 - International Journal for Philosophy of Religion 67 (1):55-60.
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44. Derrida: Profanations.Patrick O'Connor - 2010 - Continuum.
This book closely examines how the phenomenological lineage is received in deconstruction, especially the relation between deconstruction and Derrida's radical ...
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45. Lost in Translation: On the Untranslatable and its Ethical Implications for Religious Pluralism.Lovisa Bergdahl - 2009 - Journal of Philosophy of Education 43 (1):31-44.
In recent years, there have been reports about increased religious discrimination in schools. As a way of acknowledging the importance of religion and faith communities in the public sphere and to propose a solution to the exclusion of religious citizens, the political philosopher Jürgen Habermas suggests an act of translation for which both secular and religious citizens are mutually responsible. What gets lost in Habermas's translation, this paper argues, is the condition that makes translation both necessary and possible. Drawing on (...)
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46. The Secular to Come: Interrogating the Derridean "Secular".Mark Cauchi - 2009 - Journal for Cultural and Religious Theory 10 (1):25.
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47. Sufism and deconstruction: A comparative study of Derrida and Ibn arabi. By Ian Almond: Book reviews. [REVIEW]Amer Gheitury - 2009 - Heythrop Journal 50 (4):743-744.
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48. 'Messianicity' in Social Theory? A Critique of a Thesis of Jacques Derrida.Austin Harrington - 2009 - Thesis Eleven 98 (1):52-68.
Jacques Derrida's vision of 'messianicity' in his book Specters of Marx and the essay 'Faith and Knowledge: The Two Sources of “Religion” at the Limits of Reason Alone' has been widely appreciated by scholars. Yet little fundamentally critical engagement appears to have been made with some important historical-sociological questions raised by Derrida's ideas in these texts. Drawing on earlier reference-points in 20th-century critical theory and sociology, the present article argues for some objections to Derrida's presentation of the significance of religious (...)
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49. Returning to God after God: Levinas, Derrida, Ricoeur.Richard Kearney - 2009 - Research in Phenomenology 39 (2):167-183.
This essay discusses the anatheist option of returning to God after the atheistic critique of the traditional God of ontotheology. It begins by reviewing the contributions that Levinas and Derrida have made toward this position and the atheistic criticisms of Freud and Nietzsche. The work of Paul Ricoeur is then discussed, showing how the atheist critique is a necessary moment in the development of genuine faith that involves a renunciation of fear and dependency as well as a reaffirmation of life (...) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3262244462966919, "perplexity": 12046.349206279358}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764499801.40/warc/CC-MAIN-20230130034805-20230130064805-00821.warc.gz"} |
https://web2.0calc.com/questions/intigration | +0
# INTIGRATION
0
309
1
(cotx/sinx-tan^2x- tanx/cos+2x/cos^2x)dx
Guest Aug 29, 2017
#1
+93356
+3
(cotx/sinx-tan^2x- tanx/cos+2x/cos^2x)dx
NOTE I have added an x after cos as I think that you forgot it. :)
$$\int (\frac{cotx}{sinx}-tan^2x-\frac{ tanx}{cosx}+\frac{2x}{cos^2x})dx\\ =\int \frac{cotx}{sinx}dx-\int tan^2x dx-\int\frac{ tanx}{cosx} dx+\int\frac{2x}{cos^2x}dx\\ =\int \frac{cotx}{sinx}dx-\int tan^2x dx-\int\frac{ tanx}{cosx} dx+\int\frac{2x}{cos^2x}dx\\~\\ -----\\ \int \frac{cotx}{sinx}dx=\int \frac{cosx}{sin^2x}dx=\int cosx(sinx)^{-2}dx=-(sinx)^{-1}+c_1=-cosecx+c_1\\ \int tan^2x dx=\int \frac{sin^2x}{cos^2x} dx=\int\;(sec^2x-1)dx=tanx-x+c_2\\ \int\frac{ tanx}{cosx} dx=\int\frac{ sinx}{cos^2x} dx=(cosx)^{-1}+c_3=secx+c_3\\~\\ \text{So far I have }\\ =\:-cosecx-(tanx-x)-(secx)+\int\frac{2x}{cos^2x}dx\\ =\:-cosecx-tanx+x-secx+\int\frac{2x}{cos^2x}dx$$
$$=\:-cosecx-tanx+x-secx+\int\frac{2x}{cos^2x}dx\\ consider\;\;\;\int\frac{2x}{cos^2x}dx\\ =\int(2x(sec^2x)dx\\ \text{Solve using integration by parts}\\ u=2x \qquad v'=sec^2x\\ u'=2 \qquad v=tanx\\ \int\;uv'dx=uv-\int(vu')dx\\ =2xtanx-\int(2tanx)dx\\ =2xtanx-2\int(\frac{sinx}{cosx})dx\\ =2xtanx+2ln(cosx))+c_4\\~\\ \text{So my final answer is}\\ =\:-cosecx-tanx+x-secx+2xtanx+2ln(cosx)+c\\$$
Melody Aug 29, 2017
#1
+93356
+3
(cotx/sinx-tan^2x- tanx/cos+2x/cos^2x)dx
NOTE I have added an x after cos as I think that you forgot it. :)
$$\int (\frac{cotx}{sinx}-tan^2x-\frac{ tanx}{cosx}+\frac{2x}{cos^2x})dx\\ =\int \frac{cotx}{sinx}dx-\int tan^2x dx-\int\frac{ tanx}{cosx} dx+\int\frac{2x}{cos^2x}dx\\ =\int \frac{cotx}{sinx}dx-\int tan^2x dx-\int\frac{ tanx}{cosx} dx+\int\frac{2x}{cos^2x}dx\\~\\ -----\\ \int \frac{cotx}{sinx}dx=\int \frac{cosx}{sin^2x}dx=\int cosx(sinx)^{-2}dx=-(sinx)^{-1}+c_1=-cosecx+c_1\\ \int tan^2x dx=\int \frac{sin^2x}{cos^2x} dx=\int\;(sec^2x-1)dx=tanx-x+c_2\\ \int\frac{ tanx}{cosx} dx=\int\frac{ sinx}{cos^2x} dx=(cosx)^{-1}+c_3=secx+c_3\\~\\ \text{So far I have }\\ =\:-cosecx-(tanx-x)-(secx)+\int\frac{2x}{cos^2x}dx\\ =\:-cosecx-tanx+x-secx+\int\frac{2x}{cos^2x}dx$$
$$=\:-cosecx-tanx+x-secx+\int\frac{2x}{cos^2x}dx\\ consider\;\;\;\int\frac{2x}{cos^2x}dx\\ =\int(2x(sec^2x)dx\\ \text{Solve using integration by parts}\\ u=2x \qquad v'=sec^2x\\ u'=2 \qquad v=tanx\\ \int\;uv'dx=uv-\int(vu')dx\\ =2xtanx-\int(2tanx)dx\\ =2xtanx-2\int(\frac{sinx}{cosx})dx\\ =2xtanx+2ln(cosx))+c_4\\~\\ \text{So my final answer is}\\ =\:-cosecx-tanx+x-secx+2xtanx+2ln(cosx)+c\\$$
Melody Aug 29, 2017 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9985681176185608, "perplexity": 8422.433302104104}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267161350.69/warc/CC-MAIN-20180925083639-20180925104039-00503.warc.gz"} |
https://www.physicsforums.com/threads/system-of-equations-4-variable.298694/ | # Homework Help: System of equations 4 variable
1. Mar 10, 2009
### synergix
1. The problem statement, all variables and given/known data
Solve
2w + 2x - 5y + z = -16 (1)
-w + x + 6y - z = 15 (2)
2w - x + y + 6z = 3 (3)
w + x + 2y - z = 7 (4)
3. The attempt at a solution
(2) + (4) = 2x + 8y - 2z = 22 (5)
2(2) + (3)= x + 13y + 4z = 33(6)
2(2) + (1)= 4x + 7y - z = 14 (7)
--------------------------------------
-2(6) + (5)= -18y - 10z = -44 (8)
-4(6) + (7)= -45y - 17z = -118(9)
-------------------------------------------
-17(8) + 10 (9)= y = 432/90 (10)
then start substituting. is this the best way to do it I found it very tedious and my answers didnt check I obviously made a mistake somewhere but I cant say I know what I did wrong (w,x,y,z) (62/85,207/85,24/5,98/17)
2. Mar 10, 2009
### synergix
I found my mistake y=3
3. Mar 10, 2009
### buffordboy23
The best way to solve the problem depends on your mathematical background. It seems evident that you don't have any experience with matrices, or else you would have used likely used Gaussian elimination (which is usually quicker, especially with a computer).
The work for you to learn this tool (Gaussian elimination) in solving systems of linear equations should be relatively easy for you to obtain with your current background. If your interested, see the link with example: http://en.wikipedia.org/wiki/Gaussian_elimination#Example
4. Mar 10, 2009
### arildno
(5), (6) ,(7), (8), (9) are right.
In (10), however, the y-coefficient, (-17)*(-18)-45*10=-144, rather than -90. (RHS equals -432.
Thus, the y-value out to be 432/144=3
Thus, z=-1, and you can calculate x and w yourself.
5. Mar 10, 2009
### synergix
actually in my math course matrices are not covered for whatever reason. we stop right before the chapter on matrices. and completely skip it. I will have to ask my instructor why.
6. Mar 10, 2009
### synergix
yes somehow I got 90 from that subtraction not sure how but I figured it out now thx. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8084251880645752, "perplexity": 1025.7925330708429}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-43/segments/1539583512592.60/warc/CC-MAIN-20181020055317-20181020080817-00404.warc.gz"} |
http://mathhelpforum.com/geometry/65216-help-circles-print.html | # help on circles
• Dec 16th 2008, 03:14 AM
helloying
1 Attachment(s)
help on circles
help me solve part (b)
• Dec 16th 2008, 05:13 AM
Area
Hello -
Area of APBC = 2 x Area of triangle OBC + area of sector OAPB, found in part (a)
Area of triangle OBC = 0.5 x base x height, where base = OC and height = perpendicular distance from B to OP.
Height = OB x sin (angle BOP), and angle BOP = 2 x angle BCP (angle at centre = twice angle at circumference.
I hope you can do it now.
• Dec 17th 2008, 04:34 PM
helloying
Quote:
Hello -
Area of APBC = 2 x Area of triangle OBC + area of sector OAPB, found in part (a)
Area of triangle OBC = 0.5 x base x height, where base = OC and height = perpendicular distance from B to OP.
Height = OB x sin (angle BOP), and angle BOP = 2 x angle BCP (angle at centre = twice angle at circumference.
I hope you can do it now.
In triangle OBT we know OB = 6, angle BOT = $\frac{\pi}{3}$ and angle OBT = $90^o$. So you can work out the length of BT and hence the area of the triangle. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 2, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8242577314376831, "perplexity": 3751.0893014692656}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-40/segments/1474738662022.71/warc/CC-MAIN-20160924173742-00201-ip-10-143-35-109.ec2.internal.warc.gz"} |
https://docs.openmc.org/en/stable/usersguide/depletion.html | # 10. Depletion and Transmutation¶
OpenMC supports transport-coupled and transport-independent depletion, or burnup, calculations through the openmc.deplete Python module. OpenMC uses transmutation reaction rates to solve a set of transmutation equations that determine the evolution of nuclide densities within a material. The nuclide densities predicted at some future time are then used to determine updated reaction rates, and the process is repeated for as many timesteps as are requested.
The depletion module is designed such that the reaction rate solution (the transport “operator”) is completely isolated from the solution of the transmutation equations and the method used for advancing time.
openmc.deplete supports multiple time-integration methods for determining material compositions over time. Each method appears as a different class. For example, openmc.deplete.CECMIntegrator runs a depletion calculation using the CE/CM algorithm (deplete over a timestep using the middle-of-step reaction rates). An instance of TransportOperator is passed to one of these Integrator classes along with the timesteps and power level:
power = 1200.0e6 # watts
timesteps = [10.0, 10.0, 10.0] # days
openmc.deplete.CECMIntegrator(op, timesteps, power, timestep_units='d').integrate()
The depletion problem is executed, and once it is done a depletion_results.h5 file is written. The results can be analyzed using the openmc.deplete.Results class. This class has methods that allow for easy retrieval of k-effective, nuclide concentrations, and reaction rates over time:
results = openmc.deplete.Results("depletion_results.h5")
time, keff = results.get_keff()
Note that the coupling between the reaction rate solver and the transmutation solver happens in-memory rather than by reading/writing files on disk. OpenMC has two categories of transport operators for obtaining transmutation reaction rates.
## 10.1. Transport-coupled depletion¶
This category of operator solves the transport equation to obtain transmutation reaction rates. At present, the openmc.deplete module offers a single transport-coupled operator, openmc.deplete.CoupledOperator (which uses the OpenMC transport solver), but in principle additional transport-coupled operator classes based on other transport codes could be implemented and no changes to the depletion solver itself would be needed. The openmc.deplete.CoupledOperator class requires a Model instance containing material, geometry, and settings information:
model = openmc.Model()
...
op = openmc.deplete.CoupledOperator(model)
Any material that contains a fissionable nuclide is depleted by default, but this can behavior can be changed with the Material.depletable attribute.
Important
The volume must be specified for each material that is depleted by setting the Material.volume attribute. This is necessary in order to calculate the proper normalization of tally results based on the source rate.
### 10.1.1. Fixed-Source Transmutation¶
When the power or power_density argument is used for one of the Integrator classes, it is assumed that OpenMC is running in k-eigenvalue mode, and normalization of tally results is performed based on energy deposition. It is also possible to run a fixed-source simulation and perform normalization based on a known source rate. First, as with all fixed-source calculations, we need to set the run mode:
settings.run_mode = 'fixed source'
Additionally, all materials that you wish to deplete need to be marked as such using the Material.depletable attribute:
mat = openmc.Material()
mat.depletable = True
When constructing the CoupledOperator, you should indicate that normalization of tally results will be done based on the source rate rather than a power or power density:
op = openmc.deplete.CoupledOperator(model, normalization_mode='source-rate')
Finally, when creating a depletion integrator, use the source_rates argument:
integrator = openmc.deplete.PredictorIntegrator(op, timesteps, sources_rates=...)
As with the power argument, you can provide a different source rate for each timestep in the calculation. A zero source rate for a given timestep will result in a decay-only step, where all reaction rates are zero.
### 10.1.2. Caveats¶
#### 10.1.2.1. Energy Deposition¶
The default energy deposition mode, "fission-q", instructs the CoupledOperator to normalize reaction rates using the product of fission reaction rates and fission Q values taken from the depletion chain. This approach does not consider indirect contributions to energy deposition, such as neutron heating and energy from secondary photons. In doing this, the energy deposited during a transport calculation will be lower than expected. This causes the reaction rates to be over-adjusted to hit the user-specific power, or power density, leading to an over-depletion of burnable materials.
There are some remedies. First, the fission Q values can be directly set in a variety of ways. This requires knowing what the total fission energy release should be, including indirect components. Some examples are provided below:
# use a dictionary of fission_q values
fission_q = {"U235": 202e+6} # energy in eV
# create a Model object
model = openmc.Model(geometry, settings)
# create a modified chain and write it to a new file
chain = openmc.deplete.Chain.from_xml("chain.xml", fission_q)
chain.export_to_xml("chain_mod_q.xml")
op = openmc.deplete.CoupledOperator(model, "chain_mod_q.xml")
# alternatively, pass the modified fission Q directly to the operator
op = openmc.deplete.CoupledOperator(model, "chain.xml",
fission_q=fission_q)
A more complete way to model the energy deposition is to use the modified heating reactions described in Heating and Energy Deposition. These values can be used to normalize reaction rates instead of using the fission reaction rates with:
op = openmc.deplete.CoupledOperator(model, "chain.xml",
normalization_mode="energy-deposition")
These modified heating libraries can be generated by running the latest version of openmc.data.IncidentNeutron.from_njoy(), and will eventually be bundled into the distributed libraries.
#### 10.1.2.2. Local Spectra and Repeated Materials¶
It is not uncommon to explicitly create a single burnable material across many locations. From a pure transport perspective, there is nothing wrong with creating a single 3.5 wt.% enriched fuel fuel_3, and placing that fuel in every fuel pin in an assembly or even full core problem. This certainly expedites the model making process, but can pose issues with depletion. Under this setup, openmc.deplete will deplete a single fuel_3 material using a single set of reaction rates, and produce a single new composition for the next time step. This can be problematic if the same fuel_3 is used in very different regions of the problem.
As an example, consider a full-scale power reactor core with vacuum boundary conditions, and with fuel pins solely composed of the same fuel_3 material. The fuel pins towards the center of the problem will surely experience a more intense neutron flux and greater reaction rates than those towards the edge of the domain. This indicates that the fuel in the center should be at a more depleted state than periphery pins, at least for the fist depletion step. However, without any other instructions, OpenMC will deplete fuel_3 as a single material, and all of the fuel pins will have an identical composition at the next transport step.
This can be countered by instructing the operator to treat repeated instances of the same material as a unique material definition with:
op = openmc.deplete.CoupledOperator(model, chain_file,
diff_burnable_mats=True)
For our example problem, this would deplete fuel on the outer region of the problem with different reaction rates than those in the center. Materials will be depleted corresponding to their local neutron spectra, and have unique compositions at each transport step. The volume of the original fuel_3 material must represent the volume of all the fuel_3 in the problem. When creating the unique materials, this volume will be equally distributed across all material instances.
Note
This will increase the total memory usage and run time due to an increased number of tallies and material definitions.
## 10.2. Transport-independent depletion¶
Warning
This feature is still under heavy development and has yet to be rigorously verified. API changes and feature additions are possible and likely in the near future.
This category of operator uses pre-calculated one-group microscopic cross sections to obtain transmutation reaction rates. OpenMC provides the IndependentOperator for this method of calculation. While the one-group microscopic cross sections can be calculated using a transport solver, IndependentOperator is not directly coupled to any transport solver. The IndependentOperator class requires a openmc.Materials object, a MicroXS object, and a path to a depletion chain file:
# load in the microscopic cross sections
materials = openmc.Materials()
...
micro_xs = openmc.deplete.MicroXS.from_csv(micro_xs_path)
op = openmc.deplete.IndependentOperator(materials, micro_xs, chain_file)
Note
The same statements from Transport-coupled depletion about which materials are depleted and the requirement for depletable materials to have a specified volume also apply here.
An alternate constructor, from_nuclides(), accepts a volume and dictionary of nuclide concentrations in place of the openmc.Materials object:
nuclides = {'U234': 8.92e18,
'U235': 9.98e20,
'U238': 2.22e22,
'U236': 4.57e18,
'O16': 4.64e22,
'O17': 1.76e19}
volume = 0.5
op = openmc.deplete.IndependentOperator.from_nuclides(volume,
nuclides,
micro_xs,
chain_file,
nuc_units='atom/cm3')
A user can then define an integrator class as they would for a coupled transport-depletion calculation and follow the same steps from there.
Note
Ideally, one-group cross section data should be available for every reaction in the depletion chain. If a nuclide that has a reaction associated with it in the depletion chain is present in the nuclides parameter but not the cross section data, that reaction will not be simulated.
### 10.2.1. Generating Microscopic Cross Sections¶
Users can generate the one-group microscopic cross sections needed by IndependentOperator using the MicroXS class:
import openmc
model = openmc.Model.from_xml()
micro_xs = openmc.deplete.MicroXS.from_model(model,
model.materials[0],
chain_file)
The from_model() method will produce a MicroXS object with microscopic cross section data in units of barns, which is what IndependentOperator expects the units to be. The MicroXS class also includes functions to read in cross section data directly from a .csv file or from data arrays:
micro_xs = MicroXS.from_csv(micro_xs_path)
nuclides = ['U234', 'U235', 'U238']
reactions = ['fission', '(n,gamma)']
data = np.array([[0.1, 0.2],
[0.3, 0.4],
[0.01, 0.5]])
micro_xs = MicroXS.from_array(nuclides, reactions, data)
Important
Both from_csv() and from_array() assume the cross section values provided are in barns by defualt, but have no way of verifying this. Make sure your cross sections are in the correct units before passing to a IndependentOperator object.
### 10.2.2. Caveats¶
#### 10.2.2.1. Reaction Rate Normalization¶
The IndependentOperator class supports two methods for normalizing reaction rates:
Important
Make sure you set the correct parameter in the openmc.abc.Integrator class. Use the source_rates parameter when normalization_mode == source-rate, and use power or power_density when normalization_mode == fission-q.
1. source-rate normalization, which assumes the source_rate provided by the time integrator is a flux, and obtains the reaction rates by multiplying the cross-sections by the source-rate.
2. fission-q normalization, which uses the power or power_density provided by the time integrator to obtain reaction rates by computing a value for the flux based on this power. The general equation for the flux is
$\phi = \frac{P}{\sum\limits_i (Q_i \sigma^f_i N_i)}$
where $$P$$ is the power, $$Q_i$$ is the fission Q value for nuclide $$i$$, $$\sigma_i^f$$ is the microscopic fission cross section for nuclide $$i$$, and $$N_i$$ is the number of atoms of nuclide $$i$$. This equation makes the same assumptions and issues as discussed in Energy Deposition. Unfortunately, the proposed solution in that section does not apply here since we are decoupled from transport code. However, there is a method to converge to a more accurate value for flux by using substeps during time integration. This paper provides a good discussion of this method.
Warning
The accuracy of results when using fission-q is entirely dependent on your depletion chain. Make sure it has sufficient data to resolve the dynamics of your particular scenario.
#### 10.2.2.2. Multiple Materials¶
Running a depletion simulation with multiple materials using the source-rate normalization method treats each material as completely separate with respect to reaction rates. This can be useful for running many different cases of a particular scenario. However, running a depletion simulation with multiple materials using the fission-q normalization method treats each material as part of the same “reactor” due to how fission-q normalization accumulates energy values from each material to a single value. This behavior may change in the future.
#### 10.2.2.3. Time integration¶
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https://www.nature.com/articles/s41467-021-25219-w?error=cookies_not_supported&code=8455a68a-d0e9-4a13-bb90-07ef27a33b5c | ## Introduction
Economic choice is mediated by a large number of brain regions, including several in the prefrontal cortex1,2,3. The principles delineating the allocation of specific choice-related functions to specific regions remain unclear. On one hand, modular theories hold that specific brain regions can be associated with particular nameable functions, such as evaluation, comparison, and action selection1,4,5,6. On the other hand, distributed approaches to understanding choice hold that particular elements of choice do not correspond neatly to anatomical regions7,8,9,10. These distributed approaches are inspired by classic connectionist theories as well as by modern deep learning approaches9,11,12,13. They are also inspired by cognitive and philosophical theories of distributed cognition14,15,16, and by analogy to the form vision system, where gradient-based models have come to replace historically dominant modular models10,17.
Within the domain of distributed models, early mass-action and equipotentiality models have lately been supplanted by hierarchical distributed models3,18,19. We and others have proposed a related but conceptually distinct approach defined by a gradual transformation of information9,10,20,21. For example, specific circuits within the prefrontal cortex may be organized into a gradient, so that each anatomical region implements part of a transformation of task-relevant information from a domain of options to a domain of actions10. We have proposed that each region untangles information about the best action, which is latent in the early representations and which, through serial processing, is transformed into appropriate choice actions10. This view is inspired by and is an extension of, modern untangling-based models of form vision17.
A critical prediction of gradient-based models is that it should be possible to arrange medial prefrontal regions into a series on the basis of their functional properties. Discussions of prefrontal gradients have typically focused on the lateral surface, or, when examining the medial wall, on the rostrocaudal axis22,23,24,25,26,27,28. However, even in the lateral prefrontal cortex, there is evidence of shared functionality between distinct subregions. Differential contributions appear to be quantitative and indicative of a graded flow of information29. We were interested, instead, in the ventrodorsal dimension of the medial prefrontal cortex. Neuroeconomists have long proposed that the orbitofrontal and ventromedial prefrontal cortices serve as the entry point of choice-relevant sensory information into the prefrontal cortex and that the motor cortex serves as the output5,30,31,32. The medial wall inferior to the premotor cortex, which includes areas 14, 25, 32, and dorsal anterior cingulate cortex (dACC), which we call area 24, looks to be a likely pathway linking OFC to pre/motor areas. These regions also have prominent limbic, visceral, and reward-related functions, suggesting they may contribute to valuation and perhaps to choice as well33,34,35.
However, there are several possible functional gradients that are consistent with known anatomy. First, it could follow topology in a rough ventrodorsal direction (14→25→32→24). Second, it could match the contour of the genu of the corpus callosum (25→14→32→24). Third, cytoarchitecture suggests that the less differentiated cingulate areas (25, 32, and 24) may precede the more differentiated area 1436. Other cytoarchitectural studies suggest that pre- and subgenual regions (14, 25, and 32) may have shared functions but differ qualitatively from the postgenual 2437. These specific pathways have not, to our knowledge, been functionally evaluated. Despite this, identifying the functional gradient, if one exists, is critical for establishing the neuroscience of economic choice1.
We examined a composite dataset consisting of single-unit responses collected in these four brain regions. We included previously published data for 14, 25, and 24, and newly collected data for area 3238,39,40. Instead of looking for specific functions that would distinguish these regions from each other, we took a function-first approach: we selected key putative signatures of participation in specific elements of choice before beginning the study and then characterized each region in these functions.
Here, we show two major results. First, the regions all show signatures of all tested functions and do not differ qualitatively in whether they carry certain information or have signatures of choice processes. Second, a decoding analysis shows both stronger decodability on twelve dimensions consistent with a single gradient, specifically one that progresses from 14→25→32→24 (that is, that follows a ventrodorsal direction). This second result is complemented by a demonstration that intrinsic timescale shows the same pattern. Together these results support a specific ventrodorsal medial prefrontal gradient and, simultaneously, argue against a modular view in which conceptually distinct functions are reified in neuroanatomy.
## Results
### Behavioral results
Rhesus macaques (Macaca mulatta) performed one of two structurally similar two-alternative forced-choice gambling tasks38,39 (see Methods). Briefly, subjects chose between two risky options presented asynchronously (Fig. 1A, B). After the second offer was presented, a go cue indicated that the subject was free to shift gaze toward the target option to indicate a choice. Thus, the task was naturally divided into three epochs, corresponding to the periods immediately following offer 1, offer 2, and choice. The offer 2 epoch was the first during which the subject could compare subjective values and select an action. Note, however, that subjects can and likely do form tentative partial choices based solely on the value of the first offer39.
Behavior in these tasks has been explored at length and is not reanalyzed here (the most detailed analyses are published in ref. 41). Briefly, behavior reflected an understanding of all important task variables with very weak order or side biases. We defined the expected value of an offer as the product of the offer magnitude (in µL juice) and the probability of reward. Thus, for a basic characterization of behavior, we computed the frequency with which a given offer was chosen when it had a higher expected value. We determined the proportion of trials on which the subject chose the first offer and we compared it to the difference in expected values of the two offers for each trial. Subjects’ behavior described a sigmoidal function (Fig. 1C). Subjects most frequently chose the offer with the higher expected value (ventromedial prefrontal cortex (vmPFC) sessions: 84.55% of trials; subgenual ACC (sgACC) sessions: 78.62%; pregenual ACC (pgACC) sessions: 74.97%; dACC sessions: 75.57%; p < 0.0001 in all cases; 1-sample t test), consistent with the idea that they had a basic understanding of the task.
### Firing rates in all regions encode values of offers
We recorded neuronal activity from four brain regions: 156 neurons (106 from subject B and 50 from subject H) in vmPFC area 14, 146 neurons (77 from subject B and 69 from subject J) in sgACC area 25, 213 neurons (110 from subject B and 103 from subject V) in pgACC area 32, and 129 neurons (55 from subject B and 74 from subject J) in dACC area 24. The data from pgACC have not been previously published. Some data from vmPFC, sgACC, and dACC have been previously published, although the key analyses here have not previously been reported38,39,40,42,43,44. We collected these recordings from 4 subjects (B, H, V & J see Methods and Fig. 1D). For each area, we recorded from two subjects, although we did not use the same subjects for all areas. We did not observe marked behavioral differences across subjects and therefore did not expect nor observe qualitative differences between subjects. We collected data from dACC and sgACC in the token risky choice task; we collected data from vmPFC and pgACC in the risky choice task (Fig. 1A, B). The basic format for each of the tasks during the selected time period for analysis, from within each trial, is essentially the same. We do not believe the small differences between the two tasks influenced the results we present here.
### Neuronal activity is modulated by offer value
We examined the proportion of neurons in each region selective for the value of offer 1 during epoch 1. Figure 2B–E shows the average firing rate responses of an example neuron from each of the four regions. In all four regions, a significant proportion of neurons encoded the value of offer 1 during the offer 1 epoch (vmPFC: 16.03%; sgACC: 10.27%; pgACC: 10.98%; dACC: 26.36%; p < 0.01 in all areas, binomial test). Likewise, neurons in three of the four regions encoded the value of offer 2 during epoch 2 (vmPFC: 14.1%; sgACC: 7.53%; pgACC: 10.98%; dACC: 14.73%; p < 0.01 in all areas except sgACC (trending at p = 0.063), binomial test). Finally, neurons encoded the value of offer 1 during epoch 2 (i.e., presumably, working memory for value, vmPFC: 9.62%; sgACC: 10.27%; pgACC: 9.41%; dACC: 14.73%; p < 0.01 in all areas, binomial test; Fig. 3). We also plotted the average explained variance (r2 computed from the correlation analyses used to demonstrate neuronal modulation by offer value), for each region across time.
### Putative signatures of the choice process are found in all four regions
We next asked whether each brain region contains a value signal that reflects the integration of the two features that determine value: probability and magnitude44. For each brain region, we computed regression weights for each neuron’s normalized (z-scored) firing rates for the two variables. We then examined how those variables related to each other across the population. A positive correlation between regression coefficients indicates that both offer features are encoded using a correlated coding scheme. In other words, it indicates that the population of neurons has thrown out information about the details of the components and has begun to compute an integrated value signal44. We observed a significant positive relationship in all regions (p < 0.001 in all regions; Fig. 4A). This result indicates that feature integration is not a unique feature of any region, but instead, is broadly shared across the medial PFC.
When attention shifts from one option to another, it is possible that the same population of neurons encodes the new option in the same manner as it encoded the first one, like neurons in the visual cortex do for visual stimuli45,46,47. In other words, neurons may act as a flexible filter for value; we have called this principle attentional alignment (as opposed to a labeled line code for value46). We next asked whether the attentional alignment is a principle shared in all four of our regions. To do so, we regressed normalized firing rates from epoch 1 onto the expected value of offer 1 and regressed normalized firing rates from epoch 2 on the expected value of offer 2. We then correlated these resulting coefficients. A positive correlation is evidence for attentional alignment. All four regions exhibited significant (p < 0.01) positive correlations (Fig. 4B).
We next asked if there was evidence for direct comparison between offers by the principle of mutual inhibition38,39. We regressed normalized firing rates from epoch 2 on offer 1 onto responses from epoch 2 on offer 2. If the encoding for value 1 and value 2 during the same epoch are anti-correlated, then the encoding of one value comes at the expense of the other. It is an indication of the direct comparison of offers and thus a signal of choice. All recorded regions exhibited significant (p < 0.05) negative correlations (Fig. 4C) between regression weights. This result indicates that all four regions show evidence of value comparison via mutual inhibition.
### Overlapping neuronal populations
Next, we asked if there were distinct or shared populations of neurons encoding the previously described functions. We repeated the integration, alignment, and inhibition analyses (i.e., the correlations of select regression weights), but now with absolute (i.e., unsigned) values of the regression weights. We have previously shown that such correlations indicate shared or overlapping functional populations48. If the (unsigned) strength of encoding of one offer (or feature) is positively correlated with the degree of encoding of the other offer, then the populations associated with encoding the two variables overlap more than expected by chance. We found a significant positive correlation (vmPFC: r = 0.31; sgACC: r = 0.31; pgACC: r = 0.44; dACC: r = 0.41; p < 0.001, all areas, Pearson’s correlation) between unsigned regression coefficients for the integration function (epoch 1 firing rates regressed on offer 1 magnitude and on offer 1 probability). We also found a significant positive correlation between unsigned regression coefficients for all areas (vmPFC: r = 0.34; sgACC: r = 0.23; pgACC: r = 0.33; p < 0.01, Pearson’s correlation), except for dACC (r = 0.17, p = 0.058, Pearson’s correlation), representing alignment (epoch 1 firing rates regressed on expected value 1 and epoch 2 regressed on expected value 2). Finally, vmPFC (r = 0.29) and pgACC (r = 0.25) showed significantly positive correlations (p < 0.001 in both cases, Pearson’s correlation) between unsigned regression coefficients for inhibition (epoch 2 firing rates on the expected value of each offer). These results indicate that, in most areas and across functions, encoding is mostly supported by the same, or at least overlapping, sets of neurons.
### Intrinsic timescales are longest at the top of the anatomical gradient
The results presented so far demonstrate broadly overlapping functions across regions. We next asked whether there is evidence of a functional gradient. We first considered intrinsic timescales. Intrinsic timescales are a population-level statistic describing fluctuations in a neuronal signal that are agnostic to the task and corresponding variables32. Murray and colleagues32 proposed that intrinsic fluctuations are a function of increased modulatory strength. They suggested that increased modulation is due to increased recurrent network activity, which in turn increases along an anatomical gradient. Thus, longer intrinsic timescales would be indicative of increased modulatory strength and, therefore, a higher position along the gradient.
We estimated and compared the intrinsic timescales of each recorded region from a temporal decay function. The neural activity used to estimate the intrinsic timescales came from the last two seconds of the inter-trial interval, that is, before the onset of the first offer on the next trial (similar to ref. 32). This period is absent of any cues or information about either the previous or pending trial. We used the decay function to fit the autocorrelation of pre-trial spike data across a range of lags (see Methods). We found an increase of intrinsic timescale that seemed to map a medial prefrontal gradient onto a rough ventrodorsal gradient (vmPFC: 109.8 ms; sgACC: 152.76 ms; pgACC: 321.85 ms; dACC: 446.51 ms; Fig. 5). We confirmed a positive monotonic relationship by correlating the intrinsic timescales with the observed order (1–4) across the areas. The results showed a significant positive correlation between increasing order across the four areas, and the increasing intrinsic timescale (r = 0.98, p = 0.022, Pearson’s correlation).
### Decoding accuracy supports a clear functional gradient
We hypothesized that the accuracy with which expected value and choice can be decoded from firing rate patterns should increase along the anatomical gradient. To test this hypothesis, we trained (and cross-validated) a linear classifier to decode ten binary labels (specifically: high/low expected values for offer 1 and for offer 2, the difference between expected values of the two offers, offer position, choice, chosen offer position, chosen offer value, unchosen offer value, the choice on the previous trial, and reward on the previous trial) from firing rates. We investigated decoding accuracy for two of these variables (expected value of offer 1 and chosen offer position) in two different epochs, thereby yielding a total of 12 independent decoding analyses (see Methods).
We first looked at how accurately the offer 1 value could be decoded from firing rates in epoch 1 (Fig. 6A). The classifier decoded whether offer 1 on each trial had greater or lesser value than the mean offer value across trials significantly better than chance (binomial test, p < 0.0001) for all regions: vmPFC (61.4%), sgACC (63.1%), pgACC (69.8%), and dACC (73.7%). Notably, when we compared the proposed gradient order with the decoding accuracy distributions, decoding accuracy increased with gradient order ( = 0.81, p < 0.001, Spearman’s correlation). The same principle applied to offer 1 value in epoch 2 (a putative signature of working memory for value49; Fig. 6B). The classifier decoded whether offer 1 on each trial had greater or lesser value than the mean offer value (binomial test, p < 0.001) for all regions: vmPFC (57.7%), sgACC (60.1%), pgACC (68.5%), and dACC (69.4%). As above, decoding accuracy increased with gradient order ( = 0.69, p < 0.001, Spearman’s correlation).
We next looked at how accurately offer 2 values (greater or less than mean) could be decoded from firing rates in epoch 2 (Fig. 6C). As above, the proposed gradient order (binomial test, p < 0.0001) for all regions: vmPFC (62.6%), sgACC (64.9%), pgACC (69.2%), and dACC (66.6%), accuracy increased with gradient order ( = 0.24, p < 0.001, Spearman’s correlation). The same pattern is observed with the difference between offer values (greater or less than mean) in epoch 2 (Fig. 6D, binomial test, p < 0.001) for all regions: vmPFC (54.9%), sgACC (62.3%), pgACC (67%), and dACC (70.2%). Decoding accuracy increased with gradient order ( = 0.82, p < 0.001, Spearman’s correlation).
Next, we looked at how accurately the chosen offer (offer 1 or 2) could be decoded from firing rates in the choice epoch (Fig. 6E). Note that this variable is orthogonal to the offer side since we observed essentially no spatial biases in choice. The classifier decoded choice on each trial (binomial test, p < 0.0001) for all regions: vmPFC (64.2%), sgACC (70.5%), pgACC (70.6%), and dACC (72.5%). Decoding accuracy increased with gradient order ( = 0.77, p < 0.001, Spearman’s correlation). The same pattern is observed with the expected value of the chosen offer (Fig. 6F, binomial test, p < 0.0001) for all regions: vmPFC (66.1%), sgACC (69.1%), pgACC (69.8%), and dACC (70.8%). Decoding accuracy increased with gradient order ( = 0.59, p < 0.001, Spearman’s correlation). This pattern was also observed with the expected value of the unchosen offer (offer 1 or 2, Fig. 6G, binomial test, p < 0.0001) for all regions: vmPFC (67.1%), sgACC (68.1%), pgACC (69.3%), and dACC (66.4%). Although the effect was nearly significant, decoding accuracy did not significantly increase with gradient order ( = −0.03, p = 0.058, Spearman’s correlation).
Finally, we looked at how accurately the chosen offer (offer 1 or 2) from the previous trial could be decoded from firing rates in the current choice epoch (Fig. 6H). The classifier decoded choice on each trial (binomial test, p < 0.0001) for all regions: vmPFC (61.3%), sgACC (67.1%), pgACC (67.4%), and dACC (67.9%). Decoding accuracy increased with gradient order ( = 0.51, p < 0.001, Spearman’s correlation). The same pattern was observed with experienced reward (rewarded or not rewarded) from the previous trial (Fig. 6I, binomial test, p < 0.0001) for all regions: vmPFC (66.7%), sgACC (68.1%), pgACC (72.1%), and dACC (70.3%). Decoding accuracy increased with gradient order ( = 0.66, p < 0.001, Spearman’s correlation).
### Graded organization of coding of spatial information
We looked at how accurately the position of the offer on the monitor could be decoded from firing rates in epoch 1 (Fig. 6J). The classifier decoded whether offer 1 on each trial was on the right or left (binomial test, p < 0.0001) for all regions: vmPFC (64.5%), sgACC (69.5%), pgACC (72.6%), and dACC (77.2%). Decoding accuracy increased with gradient order ( = 0.94, p < 0.001, Spearman’s correlation). We also looked at how accurately the position of the chosen offer on the monitor could be decoded from firing rates in the choice epoch (Fig. 6K). The classifier decoded whether the chosen side on each trial was on the right or left (binomial test, p < 0.0001) for all regions: vmPFC (64.7%), sgACC (70%), pgACC (70.4%), and dACC (75.6%). Decoding accuracy increased with gradient order ( = 0.93, p < 0.001, Spearman’s correlation).
We also looked at how accurately the position of the chosen offer on the monitor could be decoded from firing rates in the post-choice epoch50 (Fig. 6L). The classifier decoded whether the chosen side on each trial was on the right or left (binomial test, p < 0.0001) for all regions: vmPFC (69.3%), sgACC (72.4%), pgACC (70.8%), and dACC (83%). Decoding accuracy increased with gradient order ( = 0.81, p < 0.001, Spearman’s correlation). Finally, we looked at the average accuracy across all 12 decoders (Fig. 6M). Average accuracy across all decoders was above chance (binomial test, p < 0.0001) for all regions: vmPFC (63.4%), sgACC (67.1%), pgACC (69.8%), and dACC (71.9%). Average decoding accuracy significantly increased with order ( = 1, p = 0.017, Spearman’s correlation).
We next asked whether the number of neurons collected in each region had some effect on measures of decodability, in case the different number of neurons collected for each region was contributing to our effects. We, therefore, decimated our datasets until each had the same number of cells (specifically, 125, a number chosen before analysis). We observed that for all of our twelve measures the order was unchanged, relative to the original results. Importantly, when we averaged the decoding accuracy across all decoders, we found a significant increase with gradient order. We conclude from this control analysis that our original findings are robust and do not depend on the number of cells in each sample.
Another possible confound comes from the fact that the expected value here is a continuous variable. If some structures have graded coding of the variable, a binary classifier may not be sensitive to this property. To address this concern, as an additional control, we performed a regression-based multinomial classifier for decoding multiple EV bins. To discretize EV, while still ensuring there would be a usable number of trials in each bin, we separated the expected value into six equally sized, consecutive bins. We separated trials based on the corresponding binned EVs and used these separated responses to construct pseudo-samples, following the same approach already described. We then trained the SVM and used the model to predict the offered and the chosen EV on an untrained cross-validation set. We found that the proposed gradient in the majority of our other findings (vmPFC->sgACC->pgACC->dACC) was also evident when we decoded these variables using multiple bins. As the results remain unchanged from the binary decoding of EV, we do not discuss them further.
### Baseline firing rates do not differ between structures
First, we asked whether there were any differences in the intrinsic firing properties of neurons between the target structures. To measure baseline firing rates in each structure, we computed the average firing rate for each neuron during the 1-s pre-trial period, from −2 s to 0 s, where time 0 was set to the onset of offer 1. (Note that this is the same time window on which we performed our analysis of intrinsic timescales, see Methods). The baseline firing rate in vmPFC was 3.11 spikes/s. The baseline firing rate in sgACC was 3.69 spikes/s. The baseline firing rate in pgACC was 0.75 spikes/s. Finally, the baseline firing rate in dACC was 5.06 spikes/s. A Spearman correlation of these baseline firing rates with the proposed order was not significant ( = 0.4, p = 0.75, Spearman correlation). As the results are non-significant, we cannot draw any additional conclusions from this analysis.
Next, we wanted to determine if variability in the firing rates differed between structures. To measure firing rate variability, we computed the average Fano Factor (FF) across neurons in each region, replicating the procedure outlined in Chang et al.51. We segmented each 500 ms epoch into 100 ms bins. For each neuron, we calculate the variance and mean across trials within a given 100 ms bin. We then computed the FF as the variance divided by the mean and averaged this FF across neurons. Finally, in order to compare the FF across structures against the proposed gradient, we performed a Spearman correlation between the average FF across time bins and the expected gradient order. Across the time bins in epoch 1, the average FF in vmPFC was 1.93 ± 0.199 (SEM). The average FF in sgACC was 1.24 ± 0.023. The average FF in pgACC was 1.23 ± 0.025. The average FF in dACC was 1.35 ± 0.042. (Epoch 2, vmPFC: 1.92 ± 0.171; sgACC: 1.24 ± 0.025; pgACC: 1.23 ± 0.024; dACC: 1.32 ± 0.042). There was no significant correlation between gradient order and FF across the structure in either epoch 1 (ρ = −0.4, p = 0.75, Spearman correlation) or epoch 2 (ρ = 0.4, p = 0.74, Spearman correlation). As the results are nonsignificant, we cannot draw any additional conclusions from this analysis.
Lastly, we reasoned that qualitative encoding differences between structures would be associated with differences in the degree of dimensionality in neural activity between structures. To measure intrinsic dimensionality, we performed a principal component analysis on the normalized firing rates across neurons in each of the offer epochs, independently for each structure. For each neuron, we isolated the firing rates from both offer epochs. We calculated the mean firing rate across trials for each 20 ms time bin. Using these average responses, we composed a matrix of time X neurons. We performed an eigenvalue decomposition and computed the explained variance due to each of the first three principal components (PCs). We then calculated the degree of change, by calculating the slope, in explained variance from the first PC to the second PC, and again from the second PC to the third. We performed this same analysis for each offer epoch independently. Finally, we asked if the change in explained variance between the first three PCs was significantly correlated with the proposed order. We found that in epoch 1, the change in explained variance between PC1 and PC2 did not significantly change with gradient order ( = −1, p = 0.083, Spearman correlation). Similarly, the change in explained variance between PC2 and PC3, in epoch 1, did not significantly change with gradient order ( = −1, p = 0.083, Spearman correlation). We found that in epoch 2, the change in explained variance between PC1 and PC2 did not significantly change with gradient order ( = −1, p = 0.083, Spearman correlation). The change in explained variance between PC2 and PC3, in epoch 2, did not significantly decrease with gradient order ( = −0.4, p = 0.75, Spearman correlation). As the results are not significant, in any of these three analyses of intrinsic properties, we were unable to identify any qualitative differences in signatures of neural activity between the target structures.
### Offer encoding latency does not differ between areas
First, we confirmed our hypothesis that there would be no differences between areas in stimulus (i.e., the offer) response latencies. For both offer 1 and offer 2, we computed the latency of neural responses (see Methods). We defined latency as the time elapsed from the onset of the offer stimulus until firing rates in the respective epoch reached their maximum within the epoch. We used a 4 (area) × 2 (offer 1 or 2) ANOVA to test for differences. Neither the main effect of area (F = 1.96, p = 0.297) nor offer number (F = 5.04, p = 0.110) was statistically significant (Fig. 3A). Neuronal responses to the onset of offer 1 reached maximum firing (spikes per millisecond) in epoch 1 after an average of 258.55 ms from the offer onset (vmPFC = 265.6 ms; sgACC = 242.5 ms; pgACC = 252 ms; dACC = 274.1 ms). Neuronal responses in epoch 2 reached their maximum, on average, 245.04 ms after the onset of offer 2 (vmPFC = 241.8 ms; sgACC = 242.2 ms; pgACC = 245.6 ms; dACC = 250.5 ms).
We also tested latency using an alternative method. Specifically, we focused on the time at which firing rates reached a significance threshold in response to the variable. We defined latency as the time elapsed from the earliest point in the epoch at which firing rates register as significantly correlated with the expected value until firing rates reached their maximum within the epoch. We used a 4 (area) × 2 (offer 1 or 2) ANOVA to test for differences. Neither the main effect of area (F = 0.89, p = 0.538) nor offer number (F = 1.23, p = 0.346) was statistically significant. Using this definition of a significance threshold, we also computed the time elapsed from the onset of the offer to the first time point at which firing rates were significantly correlated with the expected value. We averaged latency across neurons and used a 4 (area) × 2 (offer 1 or 2) ANOVA to test for differences. Neither the main effect of area (F = 1.14, p = 0.457) nor the offer number (F = 0.041, p = 0.853) was statistically significant.
Finally, we also calculated latency as the time elapsed from the onset of an offer (in each epoch) to both the peak change in firing rate and to the first significant change in firing rate, irrespective of variable encoding. To do this, we calculated the mean firing rate for each neuron across trials. We then calculated both the mean and standard deviation in firing rate across each epoch. Next, for each time bin, we calculated the absolute value of the difference between firing rate and mean firing rate. We then identified the time bin of the peak change in firing rate relative to the mean firing rate for each neuron. For each epoch, we calculated the time elapsed from the onset of the offer to the peak change in firing rate and averaged these latencies across neurons. We performed a 4 (area) × 2 (offer 1 or 2) ANOVA to look for differences in time elapsed to peak change in firing rate. For both the main effect of area (F = 0.44, p = 0.742) and the main effect of offer (F = 3.84, p = 0.145) we found no significant differences. We then defined the time of the first significant change in firing rate as the first time at which firing rates were either greater than 2 standard deviations above or below (to account for neurons with firing rates that decrease) the mean. For each neuron, we then calculated the time elapsed between the onset of the offer and this first significant change in firing rate. For each epoch, we averaged latencies across neurons and performed a 4 (area) × 2 (offer 1 or 2) ANOVA to look for differences in time elapsed to the first significant change in firing rate. For both the main effect of area (F = 0.76, p = 0.448) and the main effect of offer (F = 0.17, p = 0.912) we found no significant differences.
## Discussion
Here, we examined neuronal correlates of multiple elements of economic choice in four medial prefrontal cortex regions. Confirming and extending our previous results, we find that these regions show largely similar value-related signals38,40. Indeed, by none of the measures we chose did these regions differ qualitatively. This result suggests that the regions do not have conspicuous qualitative differences along the dimensions we studied but leaves open the possibility that they differ quantitatively. Our major finding is that, by several measures, the regions appear to be organized by the functional gradient. First, twelve basic task variables are consistently more decodable later in the gradient. These include both abstract (economic) and spatial variables. Second, the intrinsic timescale is longer later in the gradient. Overall, our results are consistent with the idea that the four regions serve as part of a roughly ventral-to-dorsal functional gradient that gradually transforms neural encodings10.
The idea that prefrontal regions have a largely gradient-based organization was pioneered by Fuster, who proposed a functional gradient from the sensory to the motor areas and involving the “association cortex” between them18. Although he (like many subsequent thinkers) was mainly focused on the lateral prefrontal cortex, the same logic may extend to medial areas. However, the most logical organization of such areas is not obvious, either anatomically or functionally. There are many possibilities. Primarily using anatomical connectivity patterns, Price and colleagues classify all four of our recorded regions in his “medial network”, which they propose are responsible for visceromotor functions, and contrasting with the “orbital network”, responsible for sensory functions52,53. Based on cytoarchitecture and laminar connectivity patterns, Barbas and Pandya36 take a somewhat different view. For them, areas 25, 24, and 32, as relatively undifferentiated cingulate cortex, are all placed in a similar, low position in a mediodorsal gradient. Area 14, split between the mediodorsal and basoventral trends, occupies a somewhat higher position in the gradient. Our results (although we interpret them differently with respect to a gradient) are not necessarily inconsistent with such a framework, as increased decodability and timescales may simply be a hallmark of less-differentiated PFC regions.
Alternatively, topology would suggest possible ventrodorsal (14→25→32→24) or genu-adhering (25→14→32→24) gradients. The first one is consistent with the idea that OFC (Price’s orbital network) serves as the entryway for economic information to the prefrontal cortex, and area 14 as its next station3,54. Our work supports the ventrodorsal hypothesis most strongly, thereby offering the first electrophysiological evidence for one specific medial prefrontal gradient. One prediction of this gradient is that medial area 9 (dorsomedial prefrontal cortex) should be one step above the recorded areas in our analyses55. We might also expect that sensory choice information is received by orbitofrontal cortical area 13, and then relayed to the medial prefrontal cortex; thus we would expect area 13 to be below the recorded areas in this gradient, to have shorter intrinsic timescales, and to have less decodable information.
Our results suggest that these four regions have largely overlapping functions in the domain of economic choice. Notably, our results do not imply that these regions have identical functions, nor that their differences are solely quantitative. Indeed, there is plentiful evidence that these regions have important qualitative differences37,56,57. To give an example, in a social aggression paradigm, activation of the ventral medial prefrontal cortex correlates with skin conductance response, perhaps reflecting its strong interactions with the hypothalamus and periaqueductal gray, while activation of the dorsal medial prefrontal cortex is more cognitive in nature58. Our results do not challenge or invalidate such categorical functional differences. Rather, they suggest that these regions have qualitative differences in some domains and quantitative differences in at least one domain, the domain of economic choice. Indeed, our results do point to a potential limitation too much of traditional functional neuroanatomy. Much of that work is focused exclusively on identifying the unique contributions of particular regions. While that work is critically important, it necessarily ignores the kinds of brain functions that are not uniquely implemented by specific regions. We believe that economic choice is one such function10.
We propose that there are essentially three primary organizations the system could take: (1) modular, (2) hierarchical, and (3) a continuum/gradient. In a modular organization, each structure would be responsible for performing some unique and distinct set of computations. The differences between structures would be qualitative. That is, the type of information encoded would differ, but there would not necessarily be differences in the amount of information encoded or the speed at which it is encoded. In a hierarchical organization, information encoding would differ both quantitatively and qualitatively between structures. By contrast, in a gradient organization information encoded by distinct structure would differ primarily only in the amount of encoded information of a given type. There is a general view in neuroeconomics that early reward representations encoded offers and value and later ones encode choice27. While there is a large body of empirical work supporting that view, our results are in keeping with several studies, included some of our own, that argue against it. In particular, in previous studies, we have demonstrated robust spatial selectivity in putative early reward regions, an indication of an action plan involving the spatial orientation of the intended choice43,59. In keeping with these previous findings, our results support an alternative view. Rather than a goods-to-action transformation, information is the same earlier in the functional gradient as it is later, which is more in line with a cognitive map that tracks choices and potential outcomes. Such representational schemes are particularly likely to be useful in complex and continuous decision-making tasks60. One possibility is that there is a modular organization of a somewhat different form than we have proposed. Specifically, it is possible that each region in the series represents a large qualitative step from the one before. Unfortunately, our data are not sufficient to differentiate this organization from smoother ones. Either way, our data are consistent with a series in which each area carries information in a progressively more legible format.
Our results demonstrate a clear monotonic organization of decodability across areas. One important question that our results do not address is the specific form of this monotonic organization. For example, it is possible that the processing occurs in a smooth and gradual form; another possibility is that it occurs in a series of steps; indeed, our data cannot reject the hypothesis that it is steplike for some variables and smooth for others. Successful adjudication between these two hypotheses would require two things, (1) much denser sampling of the medial prefrontal cortex, including medial prefrontal areas that we did not sample at all and sampling across all layers of the cortex, and (2) the development of statistical techniques that can unambiguously dissociate ramping from stepping. We are optimistic that new recording technologies will enable (1) and that the existence of data from (1) will motivate that development of (2). In any case, the specific structure of the organization of change across areas remains an open question.
A broad reading of the electrophysiological literature highlights that many functions have traces that are quite similar in multiple regions9. Many scholars draw a distinction between sensory areas, for which a strong modularity case can be made, and “association areas”. For example, as Prinz15 points out, even Fodor, a great advocate of modularity, was more willing to consider distributed function outside of sensory and motor regions61. Likewise, Uttal14 identifies Olds’ work on classical (trace) conditioning (1972), which shows that correlates of trace conditioning can be found in nearly every part of the rat brain.
## Methods
### Surgical procedures
The University Committee on Animal Resources at the University of Rochester and the University of Minnesota approved all animal procedures. Animal procedures were designed and conducted in compliance with the Public Health Service’s Guide for the Care and Use of Animals. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols (#2005-619 38127A) of the University of Minnesota. The protocol was approved by the Committee on the Ethics of Animal Experiments of the University of Minnesota (NIH permit number: A3456-01). Four male rhesus macaques (Macaca mulatta) served as subjects for both tasks. A small prosthesis head fixation was used. Animals were habituated to laboratory conditions and then trained to perform oculomotor tasks for liquid rewards. We place a Cilux recording chamber (Crist Instruments) over the area of interest (see Behavioral tasks for breakdown). We verified positioning by magnetic resonance imaging with the aid of a Brainsight system (Rogue Research). Animals received appropriate analgesics and antibiotics after all procedures. Throughout both behavioral and physiological recording sessions, we kept the chamber with regular antibiotic washes, and we sealed them with sterile caps.
### Recording sites
We approached our brain regions through standard recording grids (Crist Instruments) guided by a micromanipulator (NAN Instruments). We recorded neuronal activity from four brain regions: 156 neurons (106 from subject B and 50 from subject H) in vmPFC, 146 neurons (77 from subject B and 69 from subject J) in sgACC area 5, 213 neurons (110 from subject B and 103 from subject V) in pgACC area 32, and 129 neurons (55 from subject B and 74 from subject J) in dACC area 24.
Here, vmPFC (coordinates corresponding to area 1462) is defined as the structure rostral to the interaural plane by 29–44 mm, on the coronal plane. On the horizontal plane, it is located from 0 to 9 mm from the brain’s ventral surface. On the sagittal plane, the structure is located 0–8 mm from the medial wall (Fig. 2B).
Here, sgACC (coordinates corresponding to area 2562) is defined as the structure rostral to the interaural plane by 24–36 mm, on the coronal plane. On the horizontal plane, it is located from 17.33 to 25.12 mm from the brain’s dorsal surface. On the sagittal plane, the structure is located 0–5.38 mm from the medial wall (Fig. 2B).
Here, pgACC (coordinates corresponding to area 3262) is defined as the structure rostral to the interaural plane by 30.90–40.10 mm, on the coronal plane. On the horizontal plane, it is located from 7.30 to 15.50 mm from the brain’s dorsal surface. On the sagittal plane, the structure is located 0–4.5 mm from the medial wall (Fig. 2B).
Here, dACC (coordinates corresponding to area 2462) is defined as the structure rostral to the interaural plane by 29.50–34.50 mm, on the coronal plane. On the horizontal plane, it is located from 4.12 to 7.52 mm from the brain’s dorsal surface. On the sagittal plane, the structure is located 0–5.24 mm from the medial wall (Fig. 2B).
To confirm the recording sites, we used our Brainsight system. We corroborated the sites against structural magnetic resonance images that were acquired prior to the start of the experiment. These structural images were taken on a Siemens 3 T MAGNETOM Trio Tim, at the Rochester Center for Brain Imagine (0.5 mm voxels). During recording, loci were confirmed by listening for white and gray matter signatures and checked against the Brainsight system, to be within an error of ~1 and ~2 mm in the horizontal and vertical planes, respectively.
For consistency in how we plot our data, each brain area was assigned a color. That color was repeated in all figures corresponding to the data generated from that specific brain area. Importantly, we used an online palette generator specifically designed to allow for selecting color schemes that are visually distinguishable to people with protanopia, deuteranopia, and tritanopia (https://davidmathlogic.com/colorblind).
### Electrophysiological techniques
Either single (FHC; starting impedance 4 MΩ) or multi-contact electrodes (V-Probe, Plexon) were lowered using a microdrive (NAN Instruments) until waveforms between one and three neuron(s) were isolated. Individual action potentials were isolated on a Plexon system (Plexon, Dallas, TX) or Ripple Neuro (Salt Lake City, UT). Neurons were selected for study solely on the basis of the quality of isolation; we never preselected based on task-related response properties. All cells were hand-sorted using Plexon OLS. All collected neurons for which we managed to obtain at least 300 trials were analyzed; no neurons that surpassed our isolation criteria were excluded from the analysis.
### Eye-tracking and reward delivery
Eye position was sampled at 1000 Hz by an infrared eye-monitoring camera system (SR Research). Stimuli were controlled by a computer running Matlab (Mathworks) with Psychtoolbox and Eyelink Toolbox. Visual stimuli were colored rectangles on a computer monitor placed 57 cm from the animal and centered on its eyes (Fig. 1A). A standard solenoid valve controlled the duration of juice delivery. Solenoid calibration was performed daily.
Four monkeys performed two different tasks with the same basic structure. For the neuronal recordings in vmPFC, subjects B and H performed the risky choice task; and for dACC and sgACC, subjects B and J performed the token risky choice task (Fig. 2C). Both tasks made use of vertical rectangles indicating reward amount and probability. We have shown in a variety of contexts that this method provides reliable communication of abstract concepts such as reward, probability, delay, and rule to monkeys63,64,65,66.
Risky choice task (vmPFC and pgACC 32). All tasks were based on a standardized general structure for gambling tasks67,68,69,70. The task presented two offers on each trial. A rectangle 300 pixels tall and 80 pixels wide represented each offer (11.35° of visual angle tall and 4.08° of visual angle wide; Fig. 2B). Two parameters defined gamble offers, reward size, and probability. Two portions divided each gamble rectangle, one red and the other either gray, blue, or green. The size of the color portions signified the probability of winning a small (125 μL), medium (mean 165 μL), or large reward (mean 240 μL), respectively. We drew a uniform distribution between 0 and 100% for these probabilities. Red-colored the rest of the bar; the size of the red portion indicated the probability of no reward. Offer types were selected at random with a 43.75% probability of blue (medium magnitude) gamble, a 43.75% probability of green (high magnitude) gambles, and a 12.5% probability of gray options (safe offers).
On each trial, one offer appeared on the left side of the screen and the other appeared on the right. We randomized the sides of the first and second offers (left and right). Each offer appeared for 400 ms and was followed by a 600-ms blank period. After the offers were presented separately, a central fixation spot appeared, and the monkey fixated on it for 100 ms. Following this, both offers appeared simultaneously and the animal indicated its choice by shifting gaze to its preferred offer and maintaining fixation on it for 200 ms. Failure to maintain gaze for 200 ms did not lead to the end of the trial but instead returned the monkey to a choice state; thus monkeys were free to change their mind if they did so within 200 ms (although in our observations, they seldom did so). Following a successful 200-ms fixation, the trial immediately resolved the gamble and delivered the reward. We considered trials that took ~7 s as inattentive trials and we did not include them in the analyses (this removed ~1% of trials). Outcomes that yielded rewards were accompanied by a visual cue: a white circle in the center of the chosen offer. All trials were followed by an 800-ms intertrial interval with a blank screen.
Token risky choice task (sgACC 25 and dACC 24). Another similarly structured gambling task, where gambles each had two potential outcomes, wins or losses in terms of “tokens” displayed on the screen as cyan circles. A small reward (100 μL) was administered concurrently with gamble feedback on each trial, regardless of gamble outcome. Trials in which the monkey accumulated six or more tokens triggered an extra “jackpot” epoch in which a very large reward (300 μL) was administered (Fig. 2C).
### Behavioral analysis
To confirm the statistical validity of the behavioral results, we first identified the chosen offer (first or second) for each trial. We then calculated the proportion of trials, for each recording session, in which the offer with the higher value was chosen. We then analyzed the vector of choice proportions using a one-sample t-test, to determine if the average proportion of greater value choices was statistically different from zero.
### Reuse of data
Some of these data were previously published (vmPFC dataset in Strait et al.38; sgACC and dACC data sets in Azab and Hayden, 201739; data from pgACC have not been previously published).
### Statistical methods
We constructed peristimulus time histograms by aligning spike rasters to the presentation of the first offer and averaging firing rates across multiple trials. We calculated firing rates in 20-ms bins, but we generally analyzed them in longer (500 ms) epochs. For display, we smoothed peristimulus time histograms using a 200-ms running boxcar. Some statistical tests of neuron activity were only appropriate when applied to single neurons because of variations in response properties across the population. In such cases, a binomial test was used to determine if a significant portion of single neurons reached significance on their own, thereby allowing conclusions about the neural population as a whole.
### Offer encoding latency
We computed an average latency score for each area and both offers. First, we isolated firing rates for both epochs, as each was binned to the onset of one of the offers. Each epoch consisted of a 500 ms window constituted by 20 ms bins. Next, we calculated the average firing rate for each neuron, for each 20 ms bin, across trials. Then, for each neuron, we determined how much time (in ms) passed for a given neuron to reach its peak firing rate for the epoch. Finally, we calculated the average latency to peak firing rate across all neurons in the region.
### Intrinsic timescales
To measure intrinsic timescales, we followed similar steps previously described32. We isolated a 2-s time window preceding the onset of offer 1, to remain independent of trial variables. Using a 20 ms sliding window, we then computed the autocorrelation for the 2 s window with a given lag k$$\varDelta$$ between time i and time j, where k$$\varDelta$$ = |i − j|. The lag ranged from 20 and 720 ms. We then determined that the autocorrelation decay in each structure could be well-fit by an exponential decay function
$$R(k\varDelta )=A[{\exp }(-k\varDelta /\tau )+B],$$
where A = the amplitude of the autocorrelation, k$$\varDelta$$ = the lag, $$\tau$$ = intrinsic timescale, and B = the offset to account for long timeframes outside of the measured window. This formula follows what was previously described32.
### Decoding analysis
We built a pseudo-population of pseudo-trials. First, we isolated each epoch and collapsed the firing rates for each trial into an average for the 500 ms period. Then, we separated the data set for each neuron by the given variable label (choice of first or second offer; choice of left or right offer; offer one position left or right; offer two positions left or right; offer one value higher or lower than the mean value and offer value higher or lower than the mean). We randomly selected 1000 samples for each neuron resulting in 2n × 1000 matrices (one for each label level), where n represented the number of neurons recorded from each region. This constituted the pseudo-population or pseudo-trials. To execute the decoder, each matrix was split in half and concatenated with the half from the other label. We used one of these matrices to train a binary support vector machine, the other was used for cross-validation. We used the trained model to predict the binary label for each pseudo-trial in the cross-validation set. We then compared the predicted outcome to the known choice outcome and an accuracy rate was calculated across pseudo-trials. This process was repeated 1000 times for each target structure and for each of the given labels and epochs to get a distribution of accuracy rates. Thus, the standard error of the mean, used in displaying the error bars, represents the standard error over the variance of the cross-validations. In addition, the exact process was repeated on randomly shuffled data, to confirm that expected prediction accuracy was 50% when randomized.
We performed a Spearman correlation across decoding accuracy distributions from all structures. For each decoder, we generate a distribution of decoder accuracies from 1000 permutations per brain area. Each accuracy in the distribution was assigned a value from 1 to 4, corresponding to the proposed gradient order (1 = vmPFC, 2 = sgACC, 3 = pgACC, and 4 = dACC). We then aggregated the distributions into a single matrix and performed a Spearman correlation between the distribution of accuracies and the assigned gradient order.
### Reporting summary
Further information on research design is available in the Nature Research Reporting Summary linked to this article. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6873514652252197, "perplexity": 2230.9747704951083}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710662.60/warc/CC-MAIN-20221128203656-20221128233656-00629.warc.gz"} |
http://buzzsta.com/tags/Happy | # #happy
367.4M Posts
13 seconds ago
Not all thinking and all emotions are all of the ego. They turn into ego only when you identify with them and they take over completely, that's is to say, when they become I. - quote @eckhart.tolle ❤️. All thoughts and emotions are inner energy and if you let them control you it will drain you . #livefromyoursoul #liveinthemoment #happy #smile #eckharttolle #selflove #healthylifestyle #healthybodyandmind #fitness #exercise #yoga #yogaeverydamnday #positivevibes #positiveenergy #love #❤
13 seconds ago
バナナ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Give it a like 💙💚💛💜💖💗💘 and comment below 🙏🙏🙏🙏🙏🙏🙏 . . . . . . Ignore tags ⏬⏬⏬⏬ . . . . . . #love #instagood #me #tbt #cute #follow #followme #photooftheday #happy #tagforlikes #beautiful #self #girl #picoftheday #like4like #smile #friends #fun #like #fashion #summer #instadaily #igers #instalike #food #swag #amazing #tflers #follow4follow #bestoftheday | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9024017453193665, "perplexity": 4322.942776674023}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463607702.58/warc/CC-MAIN-20170523202350-20170523222350-00466.warc.gz"} |
http://mathematica.stackexchange.com/questions/44809/image-processing-edge-detection-of-the-tumor-on-tomogram-%D0%A1alculation-area-of-t?answertab=oldest | # Image Processing: Edge detection of the tumor on tomogram. Сalculation area of the tumor
The task is to identify the image region of the tumor.
I try to use example from documentation centre:
tom1 = Import["http://i.stack.imgur.com/mZ4fR.jpg"];
tumor = SelectComponents[
DeleteBorderComponents[ Binarize[ tom1, {0.75, 1}]],
{"Area", "Holes"}, 2800 < #1 < 2900 && #2 > 0 &];
circle = ComponentMeasurements[
ImageMultiply[ tom1, tumor],
Show[ tom1, Graphics[{Red, Thick, Circle @@ # & /@ circle}]]
but get unsatisfactory result:
i try to identify tumor like this but selection was noisy:
SelectComponents[
DeleteBorderComponents[ Binarize[ tom1, {0.75, 1}]],
{"Area", "Holes"}, 2800 < #1 < 2900 && #2 > 0 &]
So, can you help me to make clearer allocation of the tumor and then calculate the area of selection?
-
If this is a tomogram wouldn't it be better to measure the tumor volume in 3D instead of the area of a single slice? – s0rce Mar 26 '14 at 20:30
Your approach is quite good. I would smooth the data a bit and do an Opening to cut one extra part:
tom1 = Import["http://i.stack.imgur.com/mZ4fR.jpg"];
smooth = GaussianFilter[tom1, 2];
tumor = SelectComponents[
DeleteBorderComponents[
Opening[Binarize[smooth, {0.8, 1}], 1]], {"Area", "Holes"},
2000 < #1 < 2200 &];
HighlightImage[tom1, tumor]
And for the second part of your question, you can then use, as pointed out by bobthechemist
ComponentMeasurements[tumor, "Area"]
(* {1 -> 2062.} *)
-
+1. Should you include something like ComponentMeasurements[tumor, "Area"] to answer the 2nd part of the question? – bobthechemist Mar 26 '14 at 20:06
@bobthechemist I have missed this completely. Thanks. – halirutan Mar 26 '14 at 20:18 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7000685930252075, "perplexity": 4945.3515967677295}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-07/segments/1454701987329.64/warc/CC-MAIN-20160205195307-00244-ip-10-236-182-209.ec2.internal.warc.gz"} |
http://arxiver.moonhats.com/2017/06/19/pre-supernova-mixing-in-cemp-no-source-stars-ssa/ | # Pre-supernova mixing in CEMP-no source stars [SSA]
Context. CEMP-no stars are long-lived low-mass stars with a very low iron content, overabundances of carbon and no or minor signs for the presence of s- or r-elements. Although their origin is still a matter of debate, they are often considered as being made of a material ejected by a previous stellar generation (source stars). Aims. We place constraints on the source stars from the observed abundance data of CEMP-no stars. Methods. We computed source star models of 20, 32, and 60 M\${\odot}\$ at Z = 10\$^{-5}\$ with and without fast rotation. For each model we also computed a case with a late mixing event occurring between the hydrogen and helium-burning shell \$\sim\$ 200 yr before the end of the evolution. This creates a partially CNO-processed zone in the source star. We use the 12C/13C and C/N ratios observed on CEMP-no stars to put constraints on the possible source stars (mass, late mixing or not). Then, we inspect more closely the abundance data of six CEMP-no stars and select their preferred source star(s). Results. Four out of the six CEMP-no stars studied cannot be explained without the late mixing process in the source star. Two of them show nucleosynthetic signatures of a progressive mixing (due e.g. to rotation) in the source star. We also show that a 20 M\${\odot}\$ source star is preferred compared to one of 60 M\${\odot}\$ and that likely only the outer layers of the source stars were expelled to reproduce the observed 12C/13C. Conclusions. The results suggest that (1) a late mixing process could operate in some source stars, (2) a progressive mixing, possibly achieved by fast rotation, is at work in several source stars, (3) \$\sim\$ 20 M\${\odot}\$ source stars are preferred compared to \$\sim\$ 60 M\$_{\odot}\$ ones, and (4) the source star might have preferentially experienced a low energetic supernova with large fallback.
A. Choplin, S. Ekstrom, G. Meynet, et. al.
Mon, 19 Jun 17
7/48
Comments: 17 pages, 12 figures, Accepted for publication in A&A | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8779650330543518, "perplexity": 3075.317051318424}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084886964.22/warc/CC-MAIN-20180117193009-20180117213009-00371.warc.gz"} |
http://www.npsm-kps.org/journal/view.html?uid=6360&vmd=Full | Title Author Keyword ::: Volume ::: Vol. 68Vol. 67Vol. 66Vol. 65Vol. 64Vol. 63Vol. 62Vol. 61Vol. 60Vol. 59Vol. 58Vol. 57Vol. 56Vol. 55Vol. 54Vol. 53Vol. 52Vol. 51Vol. 50Vol. 49Vol. 48Vol. 47Vol. 46Vol. 45Vol. 44Vol. 43Vol. 42Vol. 41Vol. 40Vol. 39Vol. 38Vol. 37Vol. 36Vol. 35Vol. 34Vol. 33Vol. 32Vol. 31Vol. 30Vol. 29Vol. 28Vol. 27Vol. 26Vol. 25Vol. 24Vol. 23Vol. 22Vol. 21Vol. 20Vol. 19Vol. 18Vol. 17Vol. 16Vol. 15Vol. 14Vol. 13Vol. 12Vol. 11Vol. 10Vol. 9Vol. 8Vol. 7Vol. 6Vol. 5Vol. 4Vol. 3Vol. 2Vol. 1 ::: Issue ::: No. 12No. 11No. 10No. 9No. 8No. 7No. 6No. 5No. 4No. 3No. 2No. 1
https://doi.org/10.3938/NPSM.67.1264
Magnetic Property of the High-Temperature Superconductor GdBCO Coated Conductor
Byung Du PARK, Kyu Jeong SONG*
Division of Science Education (Physics) and Institute of Science Education, Chonbuck National University, Jeonju 54896, Korea
Correspondence to: songkj@jbnu.ac.kr
Received September 29, 2017; Revised October 13, 2017; Accepted October 13, 2017.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The basic electrical and magnetic superconducting properties of the commercially available High-Temperature Superconductor (HTS) GdBCO coated conductor (CC) specimens were investigated by using both a four-probe method and a magnetometer magnetization method with a physical property measurement system (PPMS). The $H_{irr}(T)$ data in the region near the superconducting temperature $T_c$ coincided very well with the power-law relation $H_{irr}$ = $H_{irr}(0)(1-T/T_{c})^{n}$. Similarly, the $H_{c2}(T)$ data agreed well with the Bardeen, Cooper, and Schrieffer (BCS) type function $H_{c2}$ = $H_{c2}(0)[1-(T/T_{c})^{\alpha}]^{\beta}$ in the region near the $T_c$. On the other hand, the irreversible magnetic moment $\Delta m_{irr}$ was obtained by measuring the magnetic moment $m(H)$. The Bean model was applied to obtain the related superconducting current density, $J_c$, of the GdBCO CC. The magnetic flux behavior was investigated from the relationship $J_c \propto H^{-\delta}$. At temperatures near $T_c$, the value of $\delta$ when the magnetic field was parallel to the ab-plane of the specimen was two times greater than the value of $\delta$ when it was parallel to the c-axis, but the difference between the $\delta$ values gradually decreased as the temperature was decreased.
PACS numbers: 74.25.-q, 74.25.F-, 74.25.Ha, 74.72.-h, 74.78.-w
Keywords: GdBCO-coated conductor, Irreversibility field, Upper critical field, Irreversibility magnetic moment, Critical current density, Giant flux creep
March 2018, 68 (3) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.30460840463638306, "perplexity": 17944.86042348176}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-17/segments/1524125937440.13/warc/CC-MAIN-20180420100911-20180420120911-00234.warc.gz"} |
http://anglo-celtic-connections.blogspot.com/2012/09/how-to-use-probability-in-genealogy.html | ## Tuesday, 4 September 2012
### How to use probability in genealogy - part 1
I've blogged previously on how genealogical proof could be made more convincing, beyond the textual reasoning presently employed, by adopting a probabilistic approach. The example here, based on the non-genealogical example in this YouTube video, uses simple arithmetic with calculations done on a spreadsheet.
This genealogical example draws on some of the evidence presented in the article "Sally Hemings's Children: A Genealogical Analysis of the Evidence" by Helen Leary published in the NGS Quarterly in September 2001 which documents why the evidence now points to Thomas Jefferson (TJ) as being the father of six of the children.
This will be a three part post, the first being where the initial believe is that it's unlikely TJ was the father, a view now held by a minority. We'll assign a probability, known as the prior probability, of 1%, or 0.01 that TJ was the father. We'll accept the opinion that it was a relative of TJ descended for the same paternal grandfather who was the children's father. We'll assign a probability of 98%, 0.98. There's also a small probability it could be someone else which we'll give the probability 1%, 0.01, to make the probability total 100%, or 1.0.
Now consider the evidence that Sally's son Eston had a "striking similarity" to TJ. We need to estimate the probability that there was a striking similarity to TJ because TJ was the father. It's called the conditional probability. I'll estimate that 5 in 10,000 sons bear a striking resemblance to their father, 1 in 10,000 a striking resemblance if descended through another male line from the same paternal grandfather, and 1 in 1,000,000 if descended from an unrelated person. These are my estimates. Yours may differ and what matters is the ratio between the conditional probabilities, not the absolute value.
The above values are entered into a spreadsheet in the second and fourth columns.
Now calculate the Joint Probability by multiplying the prior and conditional probabilities across the row. The final stage is to divide the joint probability in each row by the sum of the all the joint probabilities in the column to obtain the posterior probabilities after accounting for the striking similarity. In this case adding the information has increased the probability of TJ being the father from 0.01 to nearly 0.05, and using the Canon of Probabilities mentioned here this is a change from extremely improbable to very improbable. That's because we started off not believing that TJ was the father and the striking similarly evidence fails to provide highly significant discrimination.
Now add additional evidence, in this case the coincidence between the dates Sally Hemings conceived her children and when TJ was present at Montecello where Hemings lived. Analysis by Neiman in "Coincidence or Causal Connection" in William and Mary Quarterly, January 2000, accepted unquestioningly by Leary, gives about 1.5% chance that TJ was not the father of the six children. This is the basis for the conditional probabilities.
The analysis proceeds as before with the posterior probabilities from the "striking similarity" calculation becoming the prior probabilities in this one.
Taking both items of evidence together the probability that TJ was the father has jumped to 83% or probable. The evidence of TJ visits to Montecello is strong but without the striking similarity evidence the probability that TJ was the father would have been 50%, even odds.
If you start out doubting that TJ was the father it takes a lot of evidence to change the probabilities. The same applies if you start out doubting that a probabilistic approach can be useful in genealogy.
In future posts we'll look at starting with other initial (prior) probabilities that TJ was the father. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8766137957572937, "perplexity": 1763.3514588392695}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1410657116650.48/warc/CC-MAIN-20140914011156-00113-ip-10-196-40-205.us-west-1.compute.internal.warc.gz"} |
https://codegolf.stackexchange.com/questions/99304/find-the-unwrapped-size-of-a-list?noredirect=1 | # Find the “unwrapped size” of a list
Let's define the "unwrapped size" function u of a nested list l (containing only lists) by the following rules:
• If l is empty, then u(l) is 1.
• If l is non-empty, u(l) is equal to the sum of the unwrapped sizes of every element in l, plus one.
Your task is to write a program (or function) that takes a list as input and outputs (or returns) the unwrapped size of the list.
## Test Cases:
[] -> 1
[[[]],[]] -> 4
[[[]],[[[[]],[]]],[[[]],[[[[]],[[],[[]]]]]]] -> 19
[[[[]]]] -> 4
This is , so the shortest program (in bytes) wins.
• Can input be taken as a string, i.e. with enclosing quote marks? Can we use () instead of []? – Luis Mendo Nov 10 '16 at 15:49
• can we take input in this format [[[]][]] instead of this [[[]],[]] in your second example? – Mukul Kumar Nov 10 '16 at 16:50
• What is the size of ["This is some text [with square brackets in] ...[& maybe more than one pair]"]? – Jonathan Allan Nov 10 '16 at 16:54
• Possible duplicate of Find the occurrences of a character in an input string – James Nov 11 '16 at 4:40
• @DrMcMoylex I disagree. While counting the number of ] does seem to be the shortest solution in many languages, there are also a lot of answers that actually solve this challenge via list manipulation, and at least in esolangs counting the occurrences of a fixed character is also quite different from counting the occurrences of an input character. – Martin Ender Nov 11 '16 at 8:19
# Retina, 1 byte
]
Try it online! (The first line enables a linefeed-separated test suite.)
By default, Retina counts the number of matches of the given regex in the input. The unwrapped size is simply equal to the number of [] pairs in the input and therefore to the number of ].
• Thre right tool for the job! – Cyoce Nov 11 '16 at 8:21
• @MartinEnder do you ever add new functions to your language in order to save bytes in a codegolf question? – lois6b Nov 11 '16 at 9:45
• @lois6b not retroactively, but I do occasionally improve the language to make it more powerful for future uses. That said, this answer would have worked in the very first version of Retina from back when it was simply a way to run a single regex (/substitution) against the input without syntactic overhead. – Martin Ender Nov 11 '16 at 10:05
## Mathematica, 9 bytes
LeafCount
Turns out there's a built-in for that...
Note that this wouldn't work if the lists actually contained non-list elements. What LeafCount really does is count the number of atomic subexpressions. For input {{}, {{}}}, the expression actually reads:
List[List[], List[List[]]]
Here the atomic subexpressions are actually the heads List.
• Mathematica has a built-in for everything... – kirbyfan64sos Nov 10 '16 at 22:31
• @Challenger5 Oy, plagiarism. :P – Martin Ender Nov 14 '16 at 21:43
## Brainfuck, 7161 59 bytes
+[>,]<[>-[<->---]+<------[->[-]<]>[-<+>]<[-<[<]<+>>[>]]<]<.
Takes input from STDIN in the format given in the question, and outputs the character whose ASCII code is the list's "unwrapped size."
I'm still a complete amateur at Brainfuck, so there are most likely many optimizations that can still be made.
Try it online!
Ungolfed:
read input to tape
>>+[>,]<
current tape: (0 0 1 a b *c)
where abc represents input and * is IP
now we loop over each character (from the end)
this loops assumes we are starting on the (current) last char
and it zeroes the entire string by the time it finishes
[
subtract 91 from this character
technically we only subtract 85 here and correct the answer
with the 6 minus signs below
>-[<->---]
current tape: (0 0 1 a b cminus91 *0)
invert the result and put that in the next cell
+<------[->[-]<]>
current tape: (0 0 1 a b 0 *c==91)
move that result back to the original cell
[-<+>]<
current tape: (0 0 1 a b *c==91)
if the result is true we found a brace
increment the very first cell if so
[-<[<]<+>>[>]]<
current tape: (count 0 1 a *b)
]
current tape: (count *0)
<.
# JavaScript (ES6), 29 27 bytes
f=([x,...a])=>x?f(x)+f(a):1
i love it when a recursion turns out this cleanly. This is basically a depth-first search of the input, adding 1 whenever the end of an array is reached.
If an empty array were falsy in JS, this could be 24 bytes:
f=a=>a?f(a.pop())+f(a):1
But alas, it's not. Other attempts:
f=a=>a.reduce((n,x)=>n+f(x),1) // Works, but 3 bytes longer
f=a=>a.map(x=>n+=f(x),n=1)&&n // Works, but 2 bytes longer
f=a=>(x=a.pop())?f(x)+f(a):1 // Works, but 1 byte longer
f=a=>a[0]?f(a.pop())+f(a):1 // Works, but same byte count
f=a=>a+a?f(a.pop())+f(a):1 // Doesn't work on any array containing 1 sub-array
f=a=>a-1?f(a.pop())+f(a):1 // Same
• Would f=a=>a[0]?f(a.pop())+f(a):1 work? (Same byte count though.) – Neil Nov 10 '16 at 16:14
• @Neil Yes, that's one of the solutions I've already tried. I don't think it's possible to get any shorter... – ETHproductions Nov 10 '16 at 16:16
• (By the way, I would have gone for the extravagant f=a=>a.reduce((n,a)=>n+f(a),1). Now, f=(n,a)=>n+a.reduce(f,1) is only 24 bytes, but sadly the parameters are in the wrong order.) – Neil Nov 10 '16 at 16:19
• @Neil I actually did that first, except shortening it by 1 byte: f=a=>a.map(a=>n+=f(a),n=1)&&n – ETHproductions Nov 10 '16 at 16:23
• Ah, sorry, I hadn't thought to browse the edit history. – Neil Nov 10 '16 at 16:49
# Perl, 98 7 + 1 = 8 bytes
Requires the -p flag
$_=y;[; Thanks to @Dada for two byte saves (I'm loving this semicolon exploit btw) • -p to save 1 byte ;) – Dada Nov 10 '16 at 15:05 • You can use y;[; to save one more byte – Dada Nov 10 '16 at 17:57 # CJam, 7 5 bytes Thanks to Peter Taylor for removing 2 bytes! (e= instead of f=:+) r'[e= Try it online! r e# Read input '[ e# Push open bracket char e= e# Count occurrences. Implicit display # 05AB1E, 4 bytes I'[¢ I Get input as a string '[¢ Count the opening square brackets and implicitly print them Try it online! I think it can be golfed more but that 'I' is mandatory, otherwise the input is considered an actual array instead of a string • "[[[]],[[[[]],[]]],[[[]],[[[[]],[[],[[]]]]]]]" in the input removes that I requirement, though I don't know if that is allowed. – Magic Octopus Urn Nov 10 '16 at 15:49 • @carusocomputing: It's not currently allowed, but that could change (I see Luis asking the OP that same question) – Emigna Nov 10 '16 at 15:54 • Dang, 14 hours before me. – Oliver Ni Nov 11 '16 at 5:30 ## Labyrinth, 8 bytes &- #,(/! Try it online! ### Explanation This counts the opening brackets via a bit of bitwise magic. If we consider the results of the character codes of the bitwise AND of [, , and ] with 2, we get: [ , ] 2 0 0 So if we just sum up the result of this operation for each character, we get twice the value we want. As for the code itself, the 2x2 block at the beginning is a small loop. On the first iteration &- don't really do anything except that they put an explicit zero on top of the implicit ones at the bottom of the stack. This will be the running total (and it will actually be negative to save a byte later). Then the loop goes as follows: , Read character. At EOF this gives -1 which causes the instruction pointer to leave the loop. Otherwise, the loop continues. # Push the stack depth, 2. & Bitwise AND. - Subtract from running total. Once we leave the loop, the following linear bit is executed: ( Decrement to turn the -1 into a -2. / Divide negative running total by -2 to get desired result. ! Print. The IP then hits a dead and turns around. When it tries to executed / again, the program terminates due to the attempted division by zero. ## Python 3 2, 36 23 bytes lambda x:x.count("[") I noticed that u(l) is equal to the number of [ in the string representation of l, so this program tries to do that. It could probably be golfed further by finding another way to do this, though... • 23 bytes: lambda x:x.count("[") – acrolith Nov 10 '16 at 15:20 # Python, 26 bytes f=lambda a:sum(map(f,a))+1 Simple recursive formula. # C#, 46 41 bytes int u(string l){return l.Count(c=>c=='[');} l is the string of nested list. Test it here. • Use the 4 spaces (before the code) for formatting it into a code block – user41805 Nov 10 '16 at 19:23 • @KritixiLithos oops, I forgot to correctly do that. Thanks for pointing it out :) – Ave Nov 10 '16 at 19:24 • And this has to be a program or a function, this is neither. – user41805 Nov 10 '16 at 19:27 • @KritixiLithos oops, thanks for pointing it out, just fixed it. – Ave Nov 10 '16 at 19:31 • You can drop the curly braces and return by using an expression bodied function. Also char implicitly casts to int so you can use 91 instead of '[': int u(string l)=>l.Count(c=>c==91); Further, you could drop the function signature and use a lambda method: l=>l.Count(c=>c==91);. – milk Nov 10 '16 at 19:55 # Jelly, 4 bytes ߀S‘ Doesn't use string manipulation. Try it online! or verify all test cases. ### How it works ߀S‘ Main link. Argument: A (array) ߀ Map the main link over A. S Sum. For empty arrays, this yields zero. ‘ Increment. # Ruby, 13 (+1) bytes p$_.count ?[
Called with -n argument:
ruby -ne 'p $_.count ?[' EDIT: Changed to actually print out the answer • This doesn't seem to print anything. (Unless this is a REPL answer, in which case the language should be specified as Ruby REPL.) – Martin Ender Nov 10 '16 at 17:20 • @Martin Ender♦ The specification allowed for returning the value instead of printing it. – Lee W Nov 10 '16 at 19:18 • That refers to function submissions. E.g. ->s{s.count ?[} would be a valid submission. – Martin Ender Nov 10 '16 at 19:31 • Is that a general rule? – Lee W Nov 10 '16 at 19:44 • See this post for admissible I/O methods. – Martin Ender Nov 10 '16 at 19:49 # Regex, 1 byte ] Try it online! • I'm not sure Regex is a programming language, but even if it is, there's already an identical Retina answer. – Dennis Nov 12 '16 at 15:24 # Brain-Flak, 63, 61 bytes {({}[(((()()()){}){}()){({}[()])}{}]){{}(<>{}())(<>)}{}}<> Try it online! 58 bytes of code, and +3 for the -a flag enabling ASCII input. Readable version/explanation: #While non-empty: { #subtract ({}[ #91 (((()()()){}){}()){({}[()])}{} ]) #if non-zero { # Remove the difference {} #Increment the counter on the other stack (<>{}()) #Push a zero onto the main stack (<>) } #pop the left-over zero {} #endwhile } #Move back to the stack with the counter, implicitly display <> # Befunge, 2218 16 bytes ~:0#@#.!#$_3%!+
TryItOnline!
Edit: Thanks to Martin Ender for shaving off 4 bytes!
Edit2: Credit to David Holderness for optimizing out two more
# ///, 13 bytes
/[/0//]///,//
Output in unary.
Try it online!
Explanation:
/[/0/ Replace every [ with 0
/]///,// Remove every ] and ,
• How do you pronounce /// ? – roblogic Dec 16 '16 at 0:41
• @ropata Slashes – acrolith Dec 16 '16 at 12:21
# PHP, 35 bytes
<?=preg_match_all('/\[/',$argv[1]); preg_match_all finds all of the matching instances of the regular expression and returns a number, which is why the short echo tags are needed. Like most answers, it counts the number of [ in the input and outputs that number • If you use ] instead of [, you won't have to escape it. – Martin Ender Nov 10 '16 at 15:36 • count_chars()[91]; does much the same thing but is shorter. – user59178 Nov 10 '16 at 16:27 ## Racket 82 bytes (define n 0)(let p((l l))(if(null? l)(set! n(+ 1 n))(begin(p(car l))(p(cdr l)))))n Ungolfed: (define (f l) (define n 0) (let loop ((l l)) (if (null? l) (set! n (add1 n)) (begin (loop (first l)) (loop (rest l))))) n) Testing: (f '[]) (f '[[[]] []]) (f '[[[]] [[[[]] []]] [[[]] [[[[]] [[] [[]]]]]]]) (f '[[[[]]]]) Output: 1 4 19 4 # V, 10 bytes ÓÛ ÒC0@" Try it online! This contains some unprintable characters, here is the readable version: ÓÛ Ò<C-a>C0<esc>@" <C-a> represents "ctrl-a" (ASCII 0x01) and <esc> represents the escape key (ASCII 0x1b). ÓÛ " Remove all '['s " Ò<C-a> " Replace what's left with '<C-a>' (the increment command) C " Delete this line 0<esc> " And replace it with a '0' @" " Run what we just deleted as V code (A bunch of increment commands More fun, less golfy version: o0kòf]mjòd Try it online! o0<esc> " Put a '0' on the line below us k " Move back up a line ò ò " Recursively: f] " Move to a right-bracket m " Add this location to our jumplist j " Move down a line <C-a> " Increment this number <C-o> " Move to the previous location d " Delete the bracket line " Implicitly display # Scala, 15 bytes s=>s.count(92<) Ungolfed: s=>s.count(c=>92<c) count counts how many elements satisfy a predicate, in this case 92<, which is the method < of 92. # O, 15 bytes i~{1\{nJ+}d}J;J Try it here! In the input, any commas must be either removed or replaced by spaces. ## Explanation i~{1\{nJ+}d}J;J i Read a line of input. ~ Evaluate it. { }J; Define a function and save it into the J variable. Currently, the input array is at the top of the stack. 1\ Push 1 and swap it with the input array. { }d For each element in the array... Because the array was popped by d, 1 is at the TOS. nJ+ Recurse and add the result to 1. J Initiate the function call. The result is printed implicitly. ## If we're allowed to take work on a string: 10 bytes ie\']-e@-p # ><>, 2120 18 bytes 0i:0(90.;n?|3%0=+! Edit: score 1 for goto statements! Edit 2: Apparently ><> differs from Befunge in that it allows non-zero IP offset after wrapping (in other words, by using a trampoline instruction, I can wrap to (1, 0) instead of (0, 0)). Interesting. TryItOnline! ## Brainfuck, 28 bytes , [ - [ - [ >+<- [->] ] >[>>] <<< ] , ] >. Try it online. This counts the number of input characters divisible by 3, i.e. the number of ] characters. Alternate 34-byte solution counting [ characters directly and relying on 8-bit cells: , [ <-[>-<---] >------ [>-<[-]] >+<, ] >. # C, 48 46 Bytes Saved two bytes thanks to kirbyfan64sos i;f(char*v){for(i=0;*v;i+=*v++==91);return i;} i;f(char*v){for(i=0;*v;*v++^91?0:i++);return i;} Test code main() { printf("%d\n", f("[]")); printf("%d\n", f("[[[]] []]")); printf("%d\n", f("[[[]] [[[[]] []]] [[[]] [[[[]] [[] [[]]]]]]]")); } Test cases a.exe 1 4 19 • Change *v++^91?0:i++ to i+=*v==91 to save 3 bytes. – kirbyfan64sos Nov 10 '16 at 22:45 • @kirbyfan64sos Thanks! I still need to increment v but I can use i+=*v++==91 to save two bytes. – cleblanc Nov 11 '16 at 14:13 ## tinylisp repl, 39 bytes (d u(q((L)(i L(s(u(h L))(s 0(u(t L))))1 Defines a function u that can be called like (u (q ((())()) )) (for the second test case). Doing it in the repl saves 4 bytes due to auto-closed parentheses. ### Explanation (d u ) Define u as (q ) the following, unevaluated ( ) list (which acts as a function in tinylisp): (L) Given arglist of one element, L, return: (i L ) If L (is nonempty): (s(u(h L)) ) Call u on head of L and subtract (s 0 ) 0 minus (u(t L)) call u on tail of L 1 Else, 1 The x-(0-y) construct is necessary because tinylisp doesn't have a built-in addition function, only subtraction. # Befunge-98, 121110 9 bytes ~3%!+2j@. TryItOnline! Edit: Thanks to Martin Ender for shaving off a byte # Haskell, 20 19 17 bytes f s=sum[1|']'<-s] Try it online! Takes the list as string and puts a 1 in a list for each ], then sums up all the 1s. Pointfree version: (19 bytes) length.filter(>'[') Assumes , [ ] are the only chars in the string. Filters the list to get all chars greater than [, which are all ] and returns the length. Usage: Prelude> length.filter(=='[')$"[[[]],[[[[]],[]]],[[[]],[[[[]],[[],[[]]]]]]]"
19
# Bash + coreutils, 29 bytes
f()(echo \$1|tr -d -c [|wc -c)
• You can remove most of this and just do tr -d -c [|wc -c, which will by default read the list from standard input. – kirbyfan64sos Nov 10 '16 at 22:42
# DASH, 14 bytes
(ss[len;!> ="]
Simply counts ]'s. Usage:
(ss[len;!> ="]"])"[[]]"
# Bonus solution, 15 bytes
a\@+1sum ->#a#0
This one recursively counts from a real list. Usage:
(f\@+1sum ->#f#0)[[]]
` | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2065264731645584, "perplexity": 3885.7364992185426}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439738819.78/warc/CC-MAIN-20200811180239-20200811210239-00317.warc.gz"} |
https://studydaddy.com/question/acc-291-week-4-discussion-question-2 | QUESTION
# ACC 291 Week 4 Discussion Question 2
In this work ACC 291 Week 4 Discussion Question 2 you will find right answers on the following questions: "What are some common ratios used to analyze financial information? Which are the most important? What are some examples of how ratios are used in the decision making process? Two popular methods of financial statement analysis are horizontal analysis and vertical analysis. What are the differences between these two methods?"
• @
• 1 order completed
Tutor has posted answer for $5.19. See answer's preview$5.19 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.16985952854156494, "perplexity": 1289.0285101180734}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257649095.35/warc/CC-MAIN-20180323220107-20180324000107-00285.warc.gz"} |
https://eprint.iacr.org/2020/166 | ## Cryptology ePrint Archive: Report 2020/166
Non Atomic Payment Splitting in Channel Networks
Stefan Dziembowski and Paweł Kędzior
Abstract: Off-chain channel networks are one of the most promising technologies for dealing with blockchain scalability and delayed finality issues. Parties that are connected within such networks can send coins to each other without interacting with the blockchain. Moreover, these payments can be routed'' over the network. Thanks to this, even the parties that do not have a channel in common can perform payments between each other with the help of intermediaries.
In this paper, we introduce a new notion that we call Non-Atomic Payment Splitting (NAPS) protocols that allow the intermediaries in the network to split the payments recursively into several subpayments in such a way that the payment can be successful partially'' (i.e.~not all the requested amount may be transferred). This is in contrast with the existing splitting techniques that are atomic'' in the sense that they did not allow such partial payments (we compare the atomic'' and non-atomic'' approaches in the paper). We define NAPS formally and then present a protocol that we call EthNA'', that satisfies this definition. EthNA is based on very simple and efficient cryptographic tools, and in particular, it does not use any expensive cryptographic primitives. We implement a simple variant of \EthNA in Solidity and provide some benchmarks. We also report on some experiments with routing using \Ethna.
Category / Keywords: cryptographic protocols / blockchain, smart contracts, payment networks
Date: received 12 Feb 2020, last revised 20 Nov 2021
Contact author: stefan dziembowski at crypto edu pl, pk332217 at students mimuw edu pl
Available format(s): PDF | BibTeX Citation
Note: major revision (including title change)
Short URL: ia.cr/2020/166
[ Cryptology ePrint archive ] | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6209152936935425, "perplexity": 3457.258525941616}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662530553.34/warc/CC-MAIN-20220519235259-20220520025259-00218.warc.gz"} |
http://physics.stackexchange.com/questions/39090/what-is-the-physical-size-of-a-black-hole/39091 | What is the physical size of a black hole?
Something that's always confused me. How large is a black hole's physical size - not mass?
From descriptions, it would seem that the 'singularity' is a single point, but is it really?
Say for arguments sake, a 110 solar mass black hole. Obviously it's not going to be the same massive size as a 110 solar mass star (such as Cygnus OB2-12 at a physical size of 246 R☉), but would it really be a tiny point smaller than say a pin head?
-
1) We don't know what happens with objects of volume smaller than $\ell_{p}^{3}$, where $\ell_{p}$ is the Planck length, which is approximately $10^{-35}$ m. The known laws of physics do not hold for anything that small.
2) General relativity, in its classical glory, predicts that objects will collapse down to a shape with zero volume. A spinning black hole will take the shape of a ring, with a radius determined by the angular momentum and mass of the black hole. Since it is virtually impossible to tune down the angular momentum of physical objects to exactly zero, we will expect most singularities to be ring-shaped, perhaps having a $\ell_{p}$ thickness.
3) the singularity is not expected to be observable to outside observers, so most astrophysicists will instead talk about the size of the black hole horizon, which is a macroscopic size.
-
Both of these are great, thanks! – Ben Griffiths Oct 5 '12 at 0:05
Usually the size of the black hole is considered to be the point known as the Schwarzschild radius. This is the point at which time slows down to the extent that matter is never seen crossing it - one becomes frozen in time approaching this point. It is given by $2 G M/c^2$. As you can see the black hole can in principle be as small or as large as one desires, although interactions other than gravitational might prevent very tiny black holes from forming (it is an interesting question what is the smallest possible size of a black hole, to think of it). I suggest you read more about it here: http://en.wikipedia.org/wiki/Schwarzschild_radius
-
Both of these are great, thanks! I'll have to give the answer to Jerry though as that goes into a little more of the specifics of the object itself – Ben Griffiths Oct 5 '12 at 0:04
this answer might be a bit misleading. Incoming matter may appear to be frozen at the Schwarzschild radius, never seen crossing it, but in reality incoming matter does cross the Schwarzschild radius and keeps on going into the singularity at r=0. Only the outgoing light rays are frozen. So the real size of any black hole is 0, as stated in the first answer. Of course this does not take into account any quantum effect at Planck length. – magma Oct 6 '12 at 15:26
Is this really true though? I was wondering about this myself. If you look at the coordinates of the objects as the asymptotic observer sees it, the object approaching the event horizon actually slows down and does not cross the horizon. I am happy to rewrite my answer if you can convince me that it is only the light rays that make the object appear as if it had not crossed the horizon but that it actually did. – SMeznaric Oct 7 '12 at 19:28
BH is usually defined to be a region of spacetime where nothing can come out of. In that sense, an event horizon (for stationary BH) is the boundary of a BH. – Demian Cho Oct 11 '12 at 21:52
In-fall object crosses horizon in in its own frame and hit the singularity in finite proper time in BH. – Demian Cho Oct 11 '12 at 21:54 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7422990202903748, "perplexity": 209.59623608152538}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1406510273676.54/warc/CC-MAIN-20140728011753-00083-ip-10-146-231-18.ec2.internal.warc.gz"} |
https://www.ncbi.nlm.nih.gov/pubmed/9002493?dopt=Abstract | Format
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JAMA. 1997 Jan 22-29;277(4):307-11.
# The costs of adverse drug events in hospitalized patients. Adverse Drug Events Prevention Study Group.
### Author information
1
Division of General Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
### Abstract
#### DESIGN:
Nested case-control study within a prospective cohort study.
#### PARTICIPANTS:
The cohort included 4108 admissions to a stratified random sample of 11 medical and surgical units in 2 tertiary-care hospitals over a 6-month period. Cases were patients with an ADE, and the control for each case was the patient on the same unit as the case with the most similar pre-event length of stay.
#### MAIN OUTCOME MEASURES:
Postevent length of stay and total costs.
#### METHODS:
Incidents were detected by self-report stimulated by nurses and pharmacists and by daily chart review, and were classified as to whether they represented ADEs. Information on length of stay and charges was obtained from billing data, and costs were estimated by multiplying components of charges times hospital-specific ratios of costs to charges.
#### RESULTS:
During the study period, there were 247 ADEs among 207 admissions. After outliers and multiple episodes were excluded, there were 190 ADEs, of which 60 were preventable. In paired regression analyses adjusting for multiple factors, including severity, comorbidity, and case mix, the additional length of stay associated with an ADE was 2.2 days (P=.04), and the increase in cost associated with an ADE was $3244 (P=.04). For preventable ADEs, the increases were 4.6 days in length of stay (P=.03) and$5857 in total cost (P=.07). After adjusting for our sampling strategy, the estimated postevent costs attributable to an ADE were $2595 for all ADEs and$4685 for preventable ADEs. Based on these costs and data about the incidence of ADEs, we estimate that the annual costs attributable to all ADEs and preventable ADEs for a 700-bed teaching hospital are $5.6 million and$2.8 million, respectively.
#### CONCLUSIONS:
The substantial costs of ADEs to hospitals justify investment in efforts to prevent these events. Moreover, these estimates are conservative because they do not include the costs of injuries to patients or malpractice costs.
PMID:
9002493
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https://gmatclub.com/forum/mary-s-annual-income-is-15-000-and-john-s-annual-income-is-148714.html | It is currently 17 Dec 2017, 13:53
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04 Mar 2013, 06:50
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Mary’s annual income is $15,000 and John’s annual income is$18,000. By how much must Mary’s annual income increase so that it constitutes 55% of Mary and John’s combined income?
(A) $3,000 (B)$4,000
(C) $7,000 (D)$11,000
(E) $25,000 Source: Gmat Hacks 1800 [Reveal] Spoiler: OA _________________ Kudos [?]: 277 [2], given: 91 Director Status: Tutor - BrushMyQuant Joined: 05 Apr 2011 Posts: 613 Kudos [?]: 814 [1], given: 59 Location: India Concentration: Finance, Marketing Schools: XLRI (A) GMAT 1: 700 Q51 V31 GPA: 3 WE: Information Technology (Computer Software) Re: Mary’s annual income is$15,000 and John’s annual income is [#permalink]
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04 Mar 2013, 07:02
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megafan wrote:
Mary’s annual income is $15,000 and John’s annual income is$18,000. By how much must Mary’s annual income increase so that it constitutes 55% of Mary and John’s combined income?
(A) $3,000 (B)$4,000
(C) $7,000 (D)$11,000
(E) $25,000 Source: Gmat Hacks 1800 Let Mary's income increase by x, then the equation will be 15,000 + x= (55/100)* (15,000 + x + 18000 ) 15,000 + x = (11/20) * (33,000 + x) 300,000 + 20x = 11x + 363,000 9 x = 63,000 x = 7,000 So, Answer will be C Hope it helps! _________________ Ankit Check my Tutoring Site -> Brush My Quant GMAT Quant Tutor How to start GMAT preparations? How to Improve Quant Score? Gmatclub Topic Tags Check out my GMAT debrief How to Solve : Statistics || Reflection of a line || Remainder Problems || Inequalities Kudos [?]: 814 [1], given: 59 Math Expert Joined: 02 Sep 2009 Posts: 42652 Kudos [?]: 135978 [1], given: 12719 Re: Mary’s annual income is$15,000 and John’s annual income is [#permalink]
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04 Mar 2013, 11:09
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megafan wrote:
Mary’s annual income is $15,000 and John’s annual income is$18,000. By how much must Mary’s annual income increase so that it constitutes 55% of Mary and John’s combined income?
(A) $3,000 (B)$4,000
(C) $7,000 (D)$11,000
(E) $25,000 Source: Gmat Hacks 1800 Plug in method works for this question perfectly. Try the middle number: if Mary's annual income increase by$7,000, her income will be $22,000 and combined income will be 22,000 + 18,000 =$40,000. 55% of $40,000 is exactly$22,000.
Hope it helps.
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04 Feb 2014, 13:23
megafan wrote:
Mary’s annual income is $15,000 and John’s annual income is$18,000. By how much must Mary’s annual income increase so that it constitutes 55% of Mary and John’s combined income?
(A) $3,000 (B)$4,000
(C) $7,000 (D)$11,000
(E) $25,000 Source: Gmat Hacks 1800 Should they mention to constitute 55% of Mary and John combined income after the increase? Cause for me it is not 100% clear. What do you guys think about the language? Cheers J Kudos [?]: 759 [0], given: 355 SVP Status: The Best Or Nothing Joined: 27 Dec 2012 Posts: 1848 Kudos [?]: 2794 [0], given: 193 Location: India Concentration: General Management, Technology WE: Information Technology (Computer Software) Re: Mary’s annual income is$15,000 and John’s annual income is [#permalink]
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23 Jun 2014, 02:33
Mary................. John ............... Total
15000 ................ 18000 ................... 33000
Lets say Mary's income increases by x
15000+x .............. 18000 .................... 33000+x
Post increment, Mary's income should constitute 55% of total combined; this also means that John's income should constitute 45%
This step helps variable "x" to be in only one side of the equation
$$\frac{45}{100} (33000+x) = 18000$$
x = 7000
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26 Mar 2015, 04:36
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megafan wrote:
Mary’s annual income is $15,000 and John’s annual income is$18,000. By how much must Mary’s annual income increase so that it constitutes 55% of Mary and John’s combined income?
(A) $3,000 (B)$4,000
(C) $7,000 (D)$11,000
(E) $25,000 Source: Gmat Hacks 1800 Current ratio is $$\frac{15000}{33000} = \frac{15}{33}$$ what should be added to denominator and numerator to make it $$\frac{55}{100}$$ or $$\frac{11}{20}$$ or $$\frac{22}{40}$$ . Adding 7 will make $$\frac{15+7}{33+7}$$ = $$\frac{22}{40}$$ Answer 7000. C _________________ Thanks, Lucky _______________________________________________________ Kindly press the to appreciate my post !! Kudos [?]: 574 [1], given: 75 Non-Human User Joined: 09 Sep 2013 Posts: 14796 Kudos [?]: 288 [0], given: 0 Re: Mary’s annual income is$15,000 and John’s annual income is [#permalink]
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Re: Mary’s annual income is $15,000 and John’s annual income is [#permalink] ### Show Tags 28 Aug 2017, 14:19 the trick is to use 11/20 rather than 0.55, there is no secret in this question. It should not be hard at all. Kudos [?]: 53 [0], given: 1489 Re: Mary’s annual income is$15,000 and John’s annual income is [#permalink] 28 Aug 2017, 14:19
Display posts from previous: Sort by | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3199189603328705, "perplexity": 21934.445377108877}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-51/segments/1512948597585.99/warc/CC-MAIN-20171217210620-20171217232620-00691.warc.gz"} |
http://mathhelpforum.com/advanced-math-topics/25039-measure-theory.html | ## Measure Theory
Can anyone recommend a math book that gives a gentle introduction to Measure Theory?
Much appreciated. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9925045967102051, "perplexity": 2632.4036663473835}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-32/segments/1438042989018.48/warc/CC-MAIN-20150728002309-00046-ip-10-236-191-2.ec2.internal.warc.gz"} |
http://mathhelpforum.com/calculus/34330-another-volume-integral.html | # Math Help - Another volume integral
1. ## Another volume integral
Let R be the region in the first quadrant bounded by the curves y = x^3 and y = 2x-x^2. Calculate the following quantities.
(a) The area of R
(I did this already and got 37/12 units squared)
(b) The volume obtained by rotating R about the x-axis
(Having trouble with this one. I feel like I know what I'm doing, but can't seem to get a satisfactory answer. I split it into two integrals:
$V = \pi \int_0^1((2x-x^2)^2 -(x^3)^2)~dx + \pi\int_{-2}^0((x^3)^2 -(2x-x^2)^2) ~dx$
But the second integral keeps returning negative volume, and I don't understand why. I am pretty sure I put the correct function on top, and that I took it over the correct interval. :/ I could just switch the sign (and hope that I did everything else correctly, it's an even problem so don't know the answer) but I wouldn't have any idea why I was doing that other than the method I thought should work didn't.
(c) The volume obtained by rotating R about the y-axis
(haven't even attempted this yet, can't get past b)
2. ## Ok
Originally Posted by angel.white
Let R be the region in the first quadrant bounded by the curves y = x^3 and y = 2x-x^2. Calculate the following quantities.
(a) The area of R
(I did this already and got 37/12 units squared)
(b) The volume obtained by rotating R about the x-axis
(Having trouble with this one. I feel like I know what I'm doing, but can't seem to get a satisfactory answer. I split it into two integrals:
$V = \pi \int_0^1((2x-x^2)^2 -(x^3)^2)~dx + \pi\int_{-2}^0((x^3)^2 -(2x-x^2)^2) ~dx$
But the second integral keeps returning negative volume, and I don't understand why. I am pretty sure I put the correct function on top, and that I took it over the correct interval. :/ I could just switch the sign (and hope that I did everything else correctly, it's an even problem so don't know the answer) but I wouldn't have any idea why I was doing that other than the method I thought should work didn't.
(c) The volume obtained by rotating R about the y-axis
(haven't even attempted this yet, can't get past b)
you should have that $V=\pi\int_{-2}^{0}x^6-(2x-x^2)^2dx$ $+\pi\int_0^1{(2x-x^2)^2-x^6dx}$...is the volume $\frac{531\pi}{35}$?
3. Originally Posted by Mathstud28
you should have that $V=\pi\int_{-2}^{0}x^6-(2x-x^2)^2dx$ $+\pi\int_0^1{(2x-x^2)^2-x^6dx}$...is the volume $\frac{531\pi}{35}$?
I don't know, it's an even problem so the book doesn't say.
I have a theory, though: Since when x <1, y<1. This means that even though the function y=x^3 appears to be on top, it is actually the inner function (once they are flipped around the x-axis, it will be on the bottom. This means that I should be integrating outer - inner all the way along, and so I can do it with a single integral $\int_{-2}^1 ((2x-x^2)^2-(x^3)^2)~dx$
I am feeling pretty confident in this answer, it makes sense to me, and explains why the integral returned negative volume earlier (because I was taking the inner radius - the outer radius). I think I got confused because I was mixing concepts for areas with concepts for volumes.
EDIT: For the last one, rotated about the y-axis, I got (63/10)*pi Does anyone have any way of checking whether this is correct?
4. Since they're asking for the first quadrant, we only need to integrate from 0 to 1.
Here are both methods for both axes.
Shells: $2{\pi}\int_{0}^{1}y(y^{\frac{1}{3}}-(1-\sqrt{1-y}))dy=\frac{41{\pi}}{105}$
Washers: ${\pi}\int_{0}^{1}\left[(2x-x^{2})^{2}-x^{6}\right]=\frac{41{\pi}}{105}dx$
Shells: $2{\pi}\int_{0}^{1}x(2x-x^{2}-x^{3})dx=\frac{13\pi}{30}$
Washers: ${\pi}\int_{0}^{1}\left[y^{\frac{2}{3}}-(1-\sqrt{1-y})^{2}\right]dy=\frac{13\pi}{30}$
5. Originally Posted by galactus
Since they're asking for the first quadrant, we only need to integrate from 0 to 1.
well . Why don't I ever read the instructions?
Thank you so much, you saved me from getting -2 points (we get negative points if we do the wrong problem)
Going back over it, I was able to get the same answers as you ^_^ I appreciate it, you've been very helpful today. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 13, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8768981099128723, "perplexity": 375.3180318420364}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-41/segments/1410657102753.15/warc/CC-MAIN-20140914011142-00045-ip-10-196-40-205.us-west-1.compute.internal.warc.gz"} |
https://socratic.org/questions/5a4671bb11ef6b47e7481091 | Physics
Topics
Question #81091
Dec 30, 2017
From Bohr's model of atom we know that the electron is held in a circular orbit by electrostatic attraction. In case of equilibrium the centripetal force is equal to the Coulomb force.
$\frac{{m}_{e} {v}^{2}}{r} = \frac{Z {k}_{e} {e}^{2}}{r} ^ 2$
where ${m}_{e}$ is mass of electron, $e$ is the charge of electron, ${k}_{e}$ is Coulomb's constant and $Z$ is the atomic number of atom and $r$ is radius of orbit.
For Hydrogen $Z = 1$, therefore above equation reduces to
$\frac{{m}_{e} {v}^{2}}{r} = \frac{{k}_{e} {e}^{2}}{r} ^ 2$
Rewriting above in terms of Kinetic energy of electron we have
$K E = \frac{1}{2} {m}_{e} {v}^{2} = \frac{1}{2} \frac{{k}_{e} {e}^{2}}{r}$ ......(1)
From Coulomb's Law have have potential energy of the system as
$P E = - \frac{{k}_{e} {e}^{2}}{r}$ .......(2)
Comparing (1) and (2) we see that
$P E = - 2 K E$ .....(3)
and Total energy
$T E = P E + K E = - K E$ ..........(4)
To check which of the given (4) statements are true you need to remember (3) and (4) and test each statement.
Also see that potential energy in ground state is taken to be zero. Potential energy of a system is dependent on the reference. With the change of reference, both $P E \mathmr{and} T E$ change.
Impact of this question
668 views around the world | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 13, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9616438746452332, "perplexity": 452.6847458507112}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964360803.6/warc/CC-MAIN-20211201143545-20211201173545-00024.warc.gz"} |
https://www.clutchprep.com/physics/practice-problems/146636/an-object-weighing-1-840-kg-has-a-volume-of-0-0015-m3-what-is-the-density-of-the | Density Video Lessons
Concept
Problem: An object weighing 1.840 kg has a volume of 0.0015 m3. what is the density of the object in g/cm3?
FREE Expert Solution
Density is given by:
$\overline{){\mathbf{d}}{\mathbf{e}}{\mathbf{n}}{\mathbf{s}}{\mathbf{i}}{\mathbf{t}}{\mathbf{y}}{\mathbf{=}}\frac{\mathbf{m}\mathbf{a}\mathbf{s}\mathbf{s}}{\mathbf{v}\mathbf{o}\mathbf{l}\mathbf{u}\mathbf{m}\mathbf{e}}}$
91% (94 ratings)
Problem Details
An object weighing 1.840 kg has a volume of 0.0015 m3. what is the density of the object in g/cm3? | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 1, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5865495800971985, "perplexity": 2887.09327711487}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780057524.58/warc/CC-MAIN-20210924110455-20210924140455-00547.warc.gz"} |
https://cs.stackexchange.com/questions/89145/dimension-of-1x1-convolution-output | Dimension of 1x1 convolution output
I am having a hard time understanding maths behind a 1x1 convolution and how is it actually performed.
Assuming that I have a 6x6x32 input to my 1x1xK convolution layer similar to the one presented in this video and shown below. I understand that I would take a 1x1x32 slice from the input ( blue in the image below), but what operation would I actually perform?
Do I just take one value, let's say at [1,1,1] of yellow and multiply each value in the input slice with this value, or do I multiply each value from the slice with the corresponding value in the 1x1x32 part.
Also what is meant by #filters? Doesn't it need to match 32 in a given example? | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8652085065841675, "perplexity": 503.12630914502455}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-10/segments/1581875145538.32/warc/CC-MAIN-20200221203000-20200221233000-00537.warc.gz"} |
https://www.mail-archive.com/search?l=ntg-context%40ntg.nl&q=date%3A20170124&a=1&o=newest | ### [NTG-context] Bug in \startdocument
Dear devs, It is really convenient to set PDF metadata in \startdocument, however I noticed that there is a bug. The PDF subject is not set using metadata:subject but with metadata:subtitle. This is not a big issue by itself but merely a little confusing. What’s worse is that using
### Re: [NTG-context] A better \definesymbol sought
On 2017-01-24 03:34, Hans Hagen wrote: On 1/24/2017 4:04 AM, Rik wrote: What I want is that the background of the page (yellow in this case) should show through. That is what is done with fill / reverse / cycle, as in: \setupbackgrounds [page]
### Re: [NTG-context] problem with math: "\left" leads to "udefined symbol" --solved (sort of)
On 1/24/2017 4:47 PM, j. van den hoff wrote: well after incrementally deleting most everything from my document I now seem to have a reproducible example: 8< \definesynonyms[MySymbol][MySymbols][\meaning] \MySymbol [whaever] {this} { means }
### Re: [NTG-context] problem with math: "\left" leads to "udefined symbol" --solved (sort of)
well after incrementally deleting most everything from my document I now seem to have a reproducible example: 8< \definesynonyms[MySymbol][MySymbols][\meaning] \MySymbol [whaever] {this} { means } \starttext \startformula x = \left ( 1 + 2
### Re: [NTG-context] problem with math: "\left" leads to "udefined symbol"
Hans Hagen writes: > > this just works here ... so can others confirm it? > > \starttext > > \startformula > x = \left ( 1 + 2 \right ) > \stopformula > > \stoptext > > Here too: resolvers | trees | analyzing 'home:texmf' resolvers | globbing | confusing
### Re: [NTG-context] problem with math: "\left" leads to "udefined symbol"
On Tue, 24 Jan 2017 15:15:09 +0100, luigi scarso wrote: On Tue, Jan 24, 2017 at 3:02 PM, Hans Hagen wrote: this just works here ... so can others confirm it? \starttext \startformula x = \left ( 1 + 2 \right ) \stopformula \stoptext no
### Re: [NTG-context] problem with math: "\left" leads to "udefined symbol"
On Tue, Jan 24, 2017 at 3:02 PM, Hans Hagen wrote: > this just works here ... so can others confirm it? > > \starttext > > \startformula > x = \left ( 1 + 2 \right ) > \stopformula > > \stoptext > > no problem here with This is LuaTeX, Version 1.0.2 (TeX Live 2017/dev)
### Re: [NTG-context] problem with math: "\left" leads to "udefined symbol"
On 1/24/2017 2:33 PM, j. van den hoff wrote: On Tue, 24 Jan 2017 14:15:08 +0100, Hans Hagen wrote: thanks for the quick reply and sorry for my not being precise. correction/addition follows: On 1/24/2017 11:33 AM, j. van den hoff wrote: hi everybody, after a 2 year hiatus
### Re: [NTG-context] problem with math: "\left" leads to "udefined symbol"
On Tue, 24 Jan 2017 14:15:08 +0100, Hans Hagen wrote: thanks for the quick reply and sorry for my not being precise. correction/addition follows: On 1/24/2017 11:33 AM, j. van den hoff wrote: hi everybody, after a 2 year hiatus I'm just giving context' a second try (so,
### Re: [NTG-context] problem with math: "\left" leads to "udefined symbol"
On 1/24/2017 11:33 AM, j. van den hoff wrote: hi everybody, after a 2 year hiatus I'm just giving context' a second try (so, really not much experience so far). I updated to the latest version (0.63) before proceeding. 0.63 what? luatex? then you need to check things as we're beyond 1.00
### Re: [NTG-context] Chapter-subtitle and a short version of a (long) chapter title to fit in the header
On 24 Jan 2017, at 09:34 , Aditya Mahajan wrote: > > On Tue, 10 Jan 2017, Robert Blackstone wrote: > >> So my main problem is that I need, in the command \startchapter, a third >> form for the chapter title to fit in the header and a compatible version >> of the setup for
### Re: [NTG-context] mathmatrix and grid: followup
Bump On 01/06/2017 10:33 AM, Henri Menke wrote: > Bump and (belated) Happy New Year! > > On 12/10/2016 10:37 AM, Henri Menke wrote: >> Bump >> >> On 11/27/2016 07:45 PM, Henri Menke wrote: >>> Bump >>> >>> On 11/22/2016 02:18 PM, Henri Menke wrote: Dear list, some time ago I asked
### [NTG-context] problem with math: "\left" leads to "udefined symbol"
hi everybody, after a 2 year hiatus I'm just giving `context' a second try (so, really not much experience so far). I updated to the latest version (0.63) before proceeding. two observations: 1. in a new document including assorted equations everything went fine until I tried something
### Re: [NTG-context] A better \definesymbol sought
On 1/24/2017 4:04 AM, Rik wrote: On 2017-01-23 14:09, Rik Kabel wrote: On 2017-01-23 00:06, Alan Braslau wrote: > On Sun, 22 Jan 2017 22:39:53 -0500 Rik Kabel > wrote: > >> So, how can I make the inner glyph (‘?’ in the example below) >> transparent, so that the | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7881028056144714, "perplexity": 10929.80816698114}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178389472.95/warc/CC-MAIN-20210309061538-20210309091538-00521.warc.gz"} |
https://tex.stackexchange.com/questions/371341/diagnosing-incorrect-indent-in-caption-of-code-using-listings-package | # Diagnosing incorrect indent in caption of code using listings package
I am using the listings package to insert code into my document, using code from a Stack Overflow answer.
In my document, the caption is shifted right by about one tabstop (relative to page number):
I am using a customized LaTeX document class (MastersDoctoralThesis), which I suspect is the issue.
Here is my MWE:
\documentclass[11pt,oneside,english,singlespacing]{MastersDoctoralThesis}
\usepackage{color}
\usepackage{xcolor}
\usepackage{listings}% http://ctan.org/pkg/listings
\usepackage{caption}
\DeclareCaptionFont{white}{\color{white}}
\DeclareCaptionFormat{listing}{\colorbox{gray}{\parbox{\textwidth}{#1#2#3}}}
\captionsetup[lstlisting]{format=listing,labelfont=white,textfont=white}
\begin{document}
Here is some code.
\begin{lstlisting}[label=some-code,caption={Some Code},language=python]
def prioritize():
while True:
if ( SOC <= 20 ):
toggleRelay( relayHigh, 'off' )
\end{lstlisting}
\end{document}
• your MWE can use that class (it's generally known (notorious one might say:-) so it should be easy to make a MWE, just start from a copy of the document and delete everything except that float and then delete any package not needed for the example. – David Carlisle May 24 '17 at 6:44
• @DavidCarlisle done... in writing my thesis I've learned a tremendous amount about LaTeX, and gradually realized I should not have used this class. But this code is going in the final section of the final appendix, so a bit late to change it now. – LShaver May 24 '17 at 14:02
Some weird interaction which I could debug (if I really had to:-) , but the log tells you that it is 106pt too wide so this works
\DeclareCaptionFormat{listing}{\hspace*{-53pt}\colorbox{gray}{\parbox{\textwidth}{#1#2#3}}\hspace*{-53pt}}
• If you are interested why this indentation occurs, see the other answer :-) – Johannes_B May 25 '17 at 7:53
The template puts a margin to all captions. What you want is to remove that margin for listings captions. Or all captions if you like. Simply add margin=0pt while setting up the captions of your listings.
\documentclass[11pt,oneside,english,singlespacing]{MastersDoctoralThesis}
\usepackage{blindtext}
\usepackage{mwepage}
\usepackage{xcolor}
\usepackage{listings}% http://ctan.org/pkg/listings
\DeclareCaptionFont{white}{\color{white}}
\DeclareCaptionFormat{listing}{\colorbox{gray}{\parbox{\textwidth}{#1#2#3}}}
\captionsetup[lstlisting]{format=listing,labelfont=white,textfont=white,margin=0pt}
\begin{document}
\blindtext
\begin{figure}
\caption{\blindtext}
\end{figure}
\begin{lstlisting}[label=some-code,caption={Some Wombat},language=python]
def prioritize():
while True:
\end{lstlisting}
\end{document}
• yes this should get the tick really:-) – David Carlisle May 25 '17 at 8:20 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8820914626121521, "perplexity": 3255.0723363182724}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-10/segments/1581875145981.35/warc/CC-MAIN-20200224193815-20200224223815-00417.warc.gz"} |
https://mitpress.mit.edu/index.php?q=books/morphology-and-computation | Hardcover | $13.75 Short | £10.50 | ISBN: 9780262193146 | 314 pp. | 6.3 x 9.1 in | April 1992 Paperback |$28.00 Short | £19.95 | ISBN: 9780262527026 | 314 pp. | 6.3 x 9.1 in | April 1992
## Overview
This book provides the first broad yet thorough coverage of issues in morphological theory. It includes a wide array of techniques and systems in computational morphology (including discussion of their limitations), and describes some unusual applications.Sproat motivates the study of computational morphology by arguing that a computational natural language system, such as a parser or a generator, must incorporate a model of morphology. He discusses a range of applications for programs with knowledge of morphology, some of which are not generally found in the literature. Sproat then provides an overview of some of the basic descriptive facts about morphology and issues in theoretical morphology and (lexical) phonology, as well as psycholinguistic evidence for human processing of morphological structure. He takes up the basic techniques that have been proposed for doing morphological processing and discusses at length various systems (such as DECOMP and KIMMO) that incorporate part or all of those techniques, pointing out the inadequacies of such systems from both a descriptive and a computational point of view. He concludes by touching on interesting peripheral areas such as the analysis of complex nominals in English, and on the main contributions of Rumelhart and McClelland's connectionism to the computational analysis of words. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.42468953132629395, "perplexity": 1434.190432240169}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-22/segments/1464049277592.42/warc/CC-MAIN-20160524002117-00138-ip-10-185-217-139.ec2.internal.warc.gz"} |
https://thecubics.com/classification-of-machines-in-physics/ | # What is Machine?
Machines are devices by which work can be done easily. Examples of machines are , hammers, scissors , wheel barrow , pulley, Crowbar or anything at all that can help you do your work at ease.
# Terminology of simple machine
1. Mechanical advantage: it is defined as the ratio of load to the Effort, that is
$M.A=\frac { L }{ E }$
where M.A = mechanical advantage, L = Load, and E = effort. Mechanical advantage depends on part on friction and the construction of the machines. So the smaller the friction the smaller the Effort and larger the mechanical advantage.
1. Velocity Ratio (V.R) of Machine: it is defined as the ratio of distance moved by the Effort to the distance moved by the load, that is
$V.R=\frac { x }{ y }$
where X = distance moved by Effort, Y = distance moved by the load and V.R = Velocity Ratio.
1. Efficiency : It can be defined as the ratio of work output to work input, that
$\varepsilon =\frac { Work\quad output }{ work\quad input } \times 100%$
where Ɛ =n Efficiency. Efficiency can also be give as
$\varepsilon =\frac { M.A }{ V.R } \times 100%$
The above equation can be used to solve problems, but it is not a basic definition of Efficiency. The equation is only the relationship between Efficiency, M.A and V.R
## Classification of Machines
Machines can be classified into, FIRST ORDER LEVER, SECOND ORDER LEVER AND THIRD ORDER LEVER, MACHINES. The position of Fulcrum Effort and Load determine whether a Machines are First, Second or Third Order.
1. First Order Lever Machine: IThey Machines that have their Fulcrum (where It is pivoted or supported) in between the Effort and the Load Example – Claw Hammer, Pliers, and Crowbar.
2. Second Order Lever: It is the type of that has it load in between the Fulcrum and Effort. Example. Nutcracker, Wheel Barrow, etc.
3. Third Order Lever Machine: This is the type of that has its Effort in between The Fulcrum and Load. Example – Fore-arm, Tongs etc.
### Friction in Machines
Friction can be defined as opposing force which act at the surface of separation of two bodies in contact. Friction opposes motion. It depends on the nature of the surface in contact, but not on the area in contact. The Frictional Force can be give as
# F = ɥR
Where μ = Coefficient of Friction, R = the reaction of weight in contact which is equal and opposite and F = Frictional force
The reaction R can also be give as
R = Mg, where M = mass of the body, g = acceleration due gravity
### How to reduce Friction
1. By using ball and roller bearing
2. Using lubricating oil
3. By streamlining
4. By smoothing and polishing
1. It makes walking and running on ground possible
2. It enable vehicle to stop
3. It converts Mechanical energy to Heart energy.
1. It opposes motion
2. It reduces the Efficiency of machine
3. It causes wears and tears in Machine’s moving parts
4. It causes unwanted heat
Examples
1. A Machine with V.R 5 requires 1000j of work to raise a load of 500N through a vertical distance of 1.5M. Find the Efficient and M.A of Machine
2. A machine has a velocity Ratio 5 and is 80% Efficient. What Effort would be needed to lift a Load of 2000N with the aid of this Machine
Solutions
(1)
Use
$\varepsilon =\frac { Work\quad output }{ work\quad input } \times 100%$
$=\frac { 500\times 1.5 }{ 1000 } 100%$
=75%
But
$\varepsilon =\frac { M.A }{ V.R } \times 100%$
Therefore,
$75=\frac { M.A }{ 5 } \times 100%=3.75$
M.A = 3.75
Solution(2)
Using
$\varepsilon \frac { M.A }{ V.R } =\frac { \frac { L }{ E } }{ V.R }$
But Ɛ = 80%
Therefore
$\frac { 80 }{ 100 } =\frac { \frac { 2000 }{ E } }{ 5 }$
or
$E=\frac { 2000 }{ 4 } =500$
Effort required = 500N | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 11, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8320974707603455, "perplexity": 1881.2141816729547}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-13/segments/1552912202506.45/warc/CC-MAIN-20190321072128-20190321094128-00176.warc.gz"} |
http://mathhelpforum.com/math-topics/195971-hey-i-m-new-here-i-need-help-intro-real-analysis-completely-lost.html | ## Hey I'm new here. I need help with Intro to Real Analysis;completely lost
Hey I'm new here.
I'm going to college to become a high school math teacher, but some of these math courses are pretty intense. Actually the only ones that are difficult are the proof based courses. I really need help.
This is my homework and I'm completely lost and unsure how to go about doing it. We started and completely went over this topic for supS and infS in our last class. That was last Thursday. We are on spring break so we have time, but it's due next Tuesday. My teacher said he would be unavailable over break for questions so I'm SoL. Help would be greatly appreciated. I hope I'm posting this in the right section of the forums. This is for Real Analysis.
1. For each set, find inf S and sup S. State whether or not these numbers are in S.
(a) S ={x : x^2 − 3 < 0}
(b) S ={y : y = (x^2)/(x^2 + 1), x ≥ 0
(c) S = {x : 0 < x < 5, sin x = 0}
2. Let S_1, S_2 be subsets of R1. Define S = {x : x = x_1 · x_2, x_1 ∈ S_1, x_2 ∈ S_2}. Find sup S and inf S in
terms of sup S_1, inf S_1, sup S_2, and inf S_2. Discuss all cases.
3. Let S be a nonempty set of real numbers that is bounded below. Let L = inf S and suppose that
L is not an element of S.
(a) Prove that every open interval containing L contains infinitely many elements of S.
(b) Prove that there is a nonincreasing sequence {x_n} such that x_n ∈ S for all n ∈ N and
lim n→∞ x_n = L. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8675742745399475, "perplexity": 910.1817215465344}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-48/segments/1448398468396.75/warc/CC-MAIN-20151124205428-00232-ip-10-71-132-137.ec2.internal.warc.gz"} |
http://www.standfirminfaith.com/?/sf/page/17979 | October 28, 2016
August 31, 2010
# [Bumped For Obvious Reasons] Anglicanism Upside Down Down Under? Understanding Lay Administration
The question of Lay Presidency of the Lord’s Supper has been placed firmly on the global Anglican agenda by the recent motion by the Synod of the Diocese of Sydney. The motion read as follows:
Synod –
(a) accepts the report concerning legal barriers to lay and diaconal administration of the Lord’s Supper which was submitted to the 3rd session of the 47th Synod, and
(b) affirms again its conviction that lay and diaconal administration of the Lord’s Supper is consistent with the teaching of Scripture, and
(c) affirms that the Lord’s Supper in this diocese may be administered by persons other than presbyters,
and requests the Diocesan Secretary to send a copy of The Lord’s Supper in Human Hands to all bishops who attended the GAFCON.
and was passed overwhelmingly. Subsequently the Archbishop made it clear that he would not consider licensing laity to administer communion, out of respect to those that objected. Thus we are now at the position where the Diocese of Sydney approves of Diaconal Administration.
Almost as soon as the news got out there were strong responses. Perhaps the most concerned were GAFCON partners who saw the move as a serious breach in Anglican order. A clear example would be the following from Peter Toon of the Prayer Book Society of the USA:
...what the Diocese of Sydney has recently re-affirmed and confirmed as its public doctrine stands in total opposition to the doctrinal and public stance of GAFCON.
This is, quite clearly, an issue where Anglicans are divided - and divided where, previously, they had stood together.
So what has moved the Synod of Sydney to take this decision, knowing that it would upset and even offend many of their global partners - partners that only months earlier they had work so hard to win over? How should orthodox Anglicans all over the Communion understand these actions? What are the convictions that drive the motion and how can it be that evangelicals at Sydney should, in good conscience, pass such a resolution without considering it to be in any way a contradiction of their dearly-held Anglican identity?
This piece is not an apologetic for that decision, although the reader should not be ignorant of the fact that I am broadly in favour of Synod’s position - which places me somewhat at odds with my blogging colleagues at Stand Firm. As things stand I am an ordained Deacon in the Diocese and I wait, after the Rector has canvassed the opinion of church members, for my Church Council’s approval for me to administer Communion. I am, myself, an object of the current controversy and I realise that even that simple fact causes distress to some of our readers.
Nevertheless, I wanted to spend the time working hard at helping our more “Catholic”-minded friends understand how Sydney had reached this point. I won’t pretend to be neutral, rather I intend to set out (to the best of my ability) how we have ended up in this place. Along the way we will tap into some of the deeper debates that have been had in this place and others about the nature of Anglican identity. That cannot be avoided. As John Richardson observed in his recent address to the Lincoln branch of Forward in Faith in the UK,
the ‘farmer’ of Anglo-Catholicism and the ‘cowman’ of Conservative Evangelicalism can, indeed, be friends
while, in the same speech laying out a great number of areas of challenge to his audience. I would suggest that our shared convictions (or, at least our claim to share convictions) should make us eager to listen to each other, particularly on areas of deeper disagreement.
### Defining the Issue
What is indicated by the term “Lay Administration”? Are we talking about assistance at Communion, what others may call “distribution”? More than that is intended. When one reads over the legion documents produced in Sydney over this issue, it immediately becomes apparent that presidency at the Lord’s Supper is indicated. This terminology is consistent with the 1662 BCP so, for example, in the prayers at Communion you have this:
Give grace, O heavenly Father, to all Bishops and Curates, that they may both by their life and doctrine set forth thy true and lively Word, and rightly and duly administer thy holy Sacraments.
and in the next notice:
EARLY beloved, on——- day next I purpose, through God’s assistance, to administer to all such as shall be religiously and devoutly disposed the most comfortable Sacrament of the Body and Blood of Christ; to be by them received in remembrance of his meritorious Cross and Passion;
Presidency, including consecration, is obviously in view. Indeed, the service is properly titled “The Order of the Administration of the Lord’s Supper”.
### Legal/Canonical Objections
The question of a legal or canonical objection is not something that can be simply ringfenced from other areas. For our Anglo-Catholic friends church order, including the matter of canons, overlaps heavily with theology. It is not simply a question of whether something is legally or canonically permitted that makes something be in good order. The endorsement of the election of Gene Robinson, for example, did not make the action any more valid.
With this in mind, we must still consider the question of legal objections. This issue was dealt with by the Standing Committe of Sydney’s synod back in 1993. The report can be found here. (A number of other relevant reports, going back over 20 years, may be found here. Such a provenance of this position should indicate to the reader a high degree of conservatism, rather than an impulsive rush, in the area of legislating for controversial changes). The report notes that the 1985 General Synod of the Church in Australia passed a canon on the ordination of Deacons. I will let the report make it’s own argument:
5. Two notable changes occur in the service. First, the restriction upon the deacon, who could previously only baptise infants in the absence of the priest,[6] is removed so that the deacon may baptise a candidate of any age and do so, if appropriate, in the presence of the priest. Second, the authority to preach, which was previously dependent upon the bishop’s permission is replaced with the bishop’s instruction: “to preach the word of God in the place to which you are licensed.” In other words, the licence to preach, which was not inherent in the BCP service, is now constitutive of the order of deacon.[7]
6. Under the 1985 canon, both of these changes are highlighted in the words of the bishop when he gives the deacon a copy of the New Testament: “Receive this sign of your authority to proclaim God’s word and to assist in the administration of the sacraments.”
7. These changes have been universally recognised as an authorisation of the deacon to preach God’s word and to administer baptism to candidates of any age. In many ways this represented a liturgical catch up as many deacons had baptised candidates other than infants, and the recognition that there are occasions when it is appropriate for a deacon to baptise, notwithstanding the presence of a priest. However, what is curious about the wording of the 1985 service is the explicit inclusion of the holy communion in the deacon’s responsibilities. On three occasions the term “administration” of the sacraments is used in the service, whereas the word “baptism” does not occur at all.
...
11. What pertains to the authority to administer baptism pertains to the authority to administer holy communion. There is no differentiation in the service between the deacon’s authority to administer either sacrament. In both cases the deacon is assisting the priest, whether it be in administering baptism or in administering holy communion.
If Deacons are to assist the Priest in baptism by performing baptisms, argued the report, then surely the same should be accepted for communion - the ordination canon made no distinction between the too. (Remember, at this point we are speaking only to the legal objections). The legal position is founded upon the premise that the Deacon’s role has been raised in all areas to that of the Priest by leglislation.
### Theological Objections
The Report cited above contains an Appendix, the contents of which are a report by the Doctrine Commission of the Diocese. Again, it would be best to allow them to speak for themselves:
2. Theological Assumptions
2.1 The Doctrine Commission accepts the finding of the 1983 report that the arguments against lay presidency at the Lord’s Supper, such as those expressed in the General Synod Doctrine Commission Report Towards a Theology of Ordination, are incorrect, and that “there is no Scriptural or doctrinal barrier to lay presidency”.
2.2 Moreover there do exist positive reasons, theological, historical and practical, for allowing lay presidency at the Lord’s Supper.
(a) The welcome development of lay preaching ministry over many years has resulted in a distortion of our Anglican order which has, in effect, elevated the Sacrament above the Word in that those authorised to preach are not necessarily authorised to preside (note the words “vice versa” in the 1985 report quoted above). To preserve the balance of Anglican order there is a need for lay ministry of the Sacrament to develop in a way corresponding to lay ministry of the Word.
(b) On the grounds that Jesus Christ alone was the proper sacramentum given us by God (1 Tim 2:3-7; 3: 14-1 6), the 16th century Reformers worked to heal the split between Word and Sacrament endemic to medieval theology and practice. Anglican writers of the period when the formularies were being composed “regarded the ministry of the word and that of the two sacraments as closely bound up together, and were, generally speaking, entirely free from those sacerdotal conceptions which put the ministry of the eucharist in a class by itself” (i) While the question of lay presidency at the Lord’s Supper hardly arose in this period, this was because lay ministry was generally only envisaged in cases of necessity or “highly remote theory”.[ii] Normally a layman could neither preach nor administer the sacraments. Where opposition to lay presidency was expressed, it was in terms of the general argument propounded by Calvin, which was based on the concept of those “called and authorised” to each and administer the sacraments.”[iii] The main stream of Anglican writers did not apply Calvin’s argument narrowly, as can be seen in their views of lay baptism, and, at least theoretically, of lay preaching. The development of Anglican lay ministry generally in more recent times has likewise not accepted a restricted application of Calvin’s principles of order to modern church life. We have recognised that lay people too may be “called and authorised” for various ministries. However the separation we now see between preaching and sacraments was inconceivable to the Reformers. This separation has developed in the climate created in Anglicanism by the theology of the 19th century Tractarian movement which reverted to pre-Reformation views of Church and ministry.[iv]
(c) It follows that the role of presiding at the Lord’s Supper should not be elevated above the role of presiding when the congregation of God’s people gathers for prayer and the hearing of God’s Word. This is not a diminution of the importance of the Lord’s Supper: it is, rather, a recognition of the importance of every gathering of God’s household. At the centre of every such assembly must be the word of Christ, the gospel of Jesus Christ and him crucified. We have rightly recognised that the headship of Christ over his household allows for any suitably mature and gifted member of the congregation to be authorised to preside at Morning and Evening Prayer (see the conclusion to the 1983 Doctrine Commission Report, 1.1 above). It follows that the prohibition of lay presidency at the Lord’s Supper is today a serious inconsistency, which has distorted Anglican order as envisaged in our formularies (see (d) below).
(d) The anomaly of churches, schools, colleges which have regular Anglican ministry, but must bring in an outside priest on certain occasions in order to conduct the Lord’s Supper suggests the “Mass priest” concept rightly rejected by our forebears.
(e) When lay people are permitted to share in every form of ministry except one in the regular meetings of the congregation, except one, the impression can be given that the prohibited thing is the essence of ordained ministry. A sacerdotal view of the priesthood is difficult to avoid. Again this is a distortion of Anglican order due to the welcome developments in lay ministry which have not however been matched in the ministry of the Sacraments.
It has been suggested to me that it is worth considering the original intent of much of the order put in place durning the 16th Century Reformation. Why, for example, were only some Priests licensed to preach their own sermons whereas all were licensed to preside at Communion? The answer, of course, is that Cranmer had provided the words for Communion, whereas sermons came from the Priest’s own pen. Hence the need for homilies.
This action was not to raise the Sacrament over the Word and its preaching but, rather, to protect what Cranmer clearly saw as of first importance - the preaching of the word of God. He was obviously no sacerdotalist.
Of course, we now have (particularly in Sydney) a situation where not only the clergy but much of the laity are theologically literate and competent. We are, rightly, licensing many men to preach. We have ended up with a situation where what was previously prioritised and reserved (the preaching of the word) no longer needs to be whereas that which could not be so readily abused and was previously not so constrained (the sacrament) is now more restricted. This is, surely, contrary to Cranmer’s original intention. His original change was gospel-minded, prioritising and protecting the word of God. Perhaps, some in Sydney are suggesting, another like-minded change is required?
The current Dean of Sydney, Philip Jensen, puts it more simply in his recent piece “Traditions Old and New”:
There is no reason to retain or to dispense with some custom just because it is old - anymore than there is any reason to embrace something because it is new. What pleases God is that we put forward the Gospel of Jesus clearly so that His people can understand His ways and respond in obedient faith.
The move from Sydney must be recognised as coming from a sincere (although some may argue incorrectly focussed) gospel imperative.
### Anglican Identity
The question of Cranmer’s original intent, outlined above, and his understanding of the gospel strike to the very heart of current discussions over the nature of Anglican Identity. Sydney Anglicans would see themselves firmly in the line of those Reformers of the 1500’s, who they understand to have be unfeignedly protestant.
This is, of course, where the real fault-line lies. Conservative evangelicals, such as those typically found in Sydney, do not see themselves as bound to tradition as their High Church friends. Indeed, they are more than happy to reject Tradition if they understand it to be contrary to the Scriptures, as they understand Cranmer and his peers felt impelled to do. It is no surprise that Sydney is a place that, while having a very low rate of usage of the Prayer Book, has a very high allegiance to the 39 Articles and the theology of the Prayer Book. It is a strange combination, but perhaps more understandable with reference to Article 34:
XXXIV. Of the Traditions of the Church.
IT is not necessary that traditions and ceremonies be in all places one or utterly alike; for at all times they have been diverse, and may be changed according to the diversity of countries, times, and men’s manners, so that nothing be ordained against God’s word. Whosoever through his private judgement willingly and purposely doth openly break the traditions and ceremonies of the Church which be not repugnant to the word of God, and be ordained and approved by common authority, ought to be rebuked openly that other may fear to do the like, as he that offendeth against common order of the Church, and hurteth the authority of the magistrate, and woundeth the conscience of the weak brethren.
Every particular or national Church hath authority to ordain, change, and abolish ceremonies or rites of the Church ordained only by man’s authority, so that all things be done to edifying.
Many here would look to that Article and see in it a mandate to change traditions and ceremonies so that the gospel be most clearly communicated to the culture in which we find ourselves.
It is not a mystery that much of the opposition to Lay Presidency from those who would be more generally included in the “orthodox” camp comes from the “Higher” church Anglo-Catholics - those who look not to Cranmer but Laud, Pusey and, of course, Newman for their identity. This, of course, is an issue we have discussed in this place before. Readers will be under no illusions as to where I stand on the matter but perhaps I might quote again from Richardson. His words may be better received as “wounds from a friend”, or at least serve to outline the nature of the evangelical objection:
...the Anglo-Catholic must face the fact that many things precious to the tradition are, in fact, at odds with the formal position of the denomination. The onus is, therefore, on the innovator to justify their position.
Above all the Anglo-Catholic must, if progress is to be made, demonstrate the coherence of his own position within Anglicanism.
As I have stated, this is a place where the 39 Articles are taken seriously. The consitution of the Australian Church sets the Articles as the standard of doctrine and in Sydney oaths to uphold that doctrine are said and believed.
### Drawing Lines?
I do not think it would be too much to state that a frank response from many in Sydney who accuse them of innovation with their move to Lay Presidency would include a challenge to consider who the real innovators were. That is not to say that in Sydney there is great antipathy amongst the leadership to Anglo-Catholicism. On the contrary. Peter Jensen worked hard at GAFCON to build as many bridges as possible. Back here in Australia he joined with Anglo-Catholics in forming the “Association for Apostolic Ministry” in response to the consecration of women bishops.
Nevertheless, the move to widen the administration of the Lord’s Supper is bound to increase, not decrease, pre-existing divisions in the Communion. What for Sydney is an imperative of the gospel is seen by others as close to a denial of it. Still, if we are to have this discussion it is better to have it as well-informed as possible as to what it is exactly that our opponent believes. I trust this article will work towards that end.
### Recent Related Posts
• That lay preaching (in the main service, as opposed to, for example, catechism) is indeed welcome. (Personally I sympathise with this to an extent, but even so the point needs to be established by reasoned argument.)
• It does not follow that because laymen can preach that they can also preside over the sacrament. This would follow (for example) if one could demonstrate that the spiritual gift required for teaching is identical to the gift required for administration. This is not clear to me. In Ephesians 4 apostles and teachers are listed as separate gifts. From the letters of Ignatius, we know that the ability to preside over the Eucharist is limited to those with the apostolic charism (the Bishops), and those whom the Bishops license to represent them (more on this later). Both these gifts may be given to the same person, but it does not follow, and indeed is violent against the text, that it has to be so.
• If the link between preaching and administration is confirmed, then, given the testimony of the Church’s tradition, it is more an argument against lay preaching than for lay administration.
• It needs to be demonstrated that the balance of Anglican order’ is something desirable (and the term should also be defined), and that restricting the administration to the presbytery destroys it.
• It is not clear that allowing only the presbytery to administer elevates the sacrament above the word. Both are sacrament and word are essential, as seen by that they each have a prominent place in the liturgy, but their relative importance cannot be determined by the form in which they take or who is authorised to preside. As an illustration, suppose that in a string quartet one member can play both the violin and the cello, while another member can only play the violin. Does this make the cello more important than the violin when they perform?
(e) When lay people are permitted to share in every form of ministry except one in the regular meetings of the congregation, except one, the impression can be given that the prohibited thing is the essence of ordained ministry. A sacerdotal view of the priesthood is difficult to avoid. Again this is a distortion of Anglican order due to the welcome developments in lay ministry which have not however been matched in the ministry of the Sacraments. Again, this point is full of logical fallacies.
• It must be demonstrated that a sacerdotal view of the presbytery is undesirable beyond all doubt (I say beyond all doubt’ because if it is true then the sacraments would be invalid if performed by a deacon; but if the administration is (incorrectly) restricted to the presbytery then there is no damage of that magnitude). (My own position is against the Roman view of the priesthood, but not with absolute certainty).
• It is not established that a sacerdotal view of the ministry automatically follows from restricting the administration to the presbytery;
• While a sacerdotal theology leads to the restriction, it may not be the only theology that leads to it. Thus it is possible to reject the sacerdotal theology and still restrict the administration to the presbytery. In the absence of a valid positive argument, arguments must be presented to reject all those theologies before the restriction can be lifted, and I do not see that this has been done.
• It must be established that the essence of the presbytery is not directed towards the Eucharist. My understanding is that it is. There must be a certain group of people licensed by the Bishop who are allowed to represent him at the Eucharist (surely you would not allow just anyone off the street to preside? there must be some determination of who can and cannot preside, and thus a Bishop’s licence); and this group must be set apart and, for identification purposes, given its own name. We may as well call them presbyters.’ In classical theology, it is precisely the relation to the Eucharist which distinguishes the presbyter from the lower’ orders (Deacon and lay, and the others—by lower I do not mean that those orders are less essential or their spiritual gifts and contributions to the church less important; I am merely adopting a traditional terminology). Aquinas is probably the wrong authority to quote in this company, but he is easily accessible and happens to be the person I first thought of. That the reformers emphasized the ministry of the word does not negate this distinction. In particular, the deacons and readers are not authorised at their ordination or licensing services to minister the sacrament; the presbyter is.
• Therefore an argument about whether the ministration of the sacrament is necessarily connected to authority in the church and the teaching of the word is irrelevant to the question of whether presbyters alone can administer. If that argument can be shown, then it would suggest that it is possible to remove those functions from the presbyter; not that other orders can preside. (In practice, I believe that that at least the functions of authority and discipline and the ability to preside both follow from the apostolic gift, so these are linked together and should be found in the same person; but that is a separate topic).
• Evangelical Anglicanism to my mind is the perfect fusion of Protestant and Catholic. It removes those Catholic heresies (sorry folks) which were developed from the fourth and fifth centuries (as an example), while maintaining those matters of order and church practice which unquestionably date from the apostolic period. For example, we do not, unlike our radical brethren, discard the Apostolic order or infant baptism along with transubstantiation. That is why I like Anglicanism so much. The restriction of the administration, being testified by the apostle’s immediate successors, is one part of catholic tradition which clearly dates from the order established by the apostles; thus it is something which we should follow.
• It goes against the clear instructions of 1662 (and earlier) BCPs that only the Presbyter can preside or say absolution. If you feel so strongly that you have to proceed with this, then form your own new church rather than rewriting the rules of ours.
• We treat the order of deacons badly enough in the Anglican church as it is. They are a separate order with separate—and vital—gifts and functions. Allowing deacons to preside further erodes the distinction between deacon and priest, which is already (as far as I can see) eroded too far in the Church of England, and diminishes the importance of what they should be doing.
[7] Posted by Boring Bloke on 11-19-2008 at 06:09 AM · [top] I am not absolutely certain of the answer myself as to the position of deacons, but accept the position of the BCP 1662 and Articles, but this question goes back to whether in the Communion we do things together or just all do our own thing. But keep digging diggers. [8] Posted by Pageantmaster ن on 11-19-2008 at 06:29 AM · [top] Also, I think it best to let the arguments stand and fall on their own merits not on the number of scholars who side with one or the other argument…its a good thing Copernicus did not let the weight of professional opinion prevent him from noting the obvious. [9] Posted by Matt Kennedy on 11-19-2008 at 06:36 AM · [top] “there must be some determination of who can and cannot preside, and thus a Bishop’s licence); and this group must be set apart and, for identification purposes, given its own name.” That they need to be approved is self evident, but why do they need to be named? We have a group of lay people who assist in communion without their being named differently. [10] Posted by Steven Pascoe on 11-19-2008 at 06:41 AM · [top] Dear David You wrote ” This action was not to raise the Sacrament over the Word and its preaching but, rather, to protect what Cranmer clearly saw as of first importance - the preaching of the word of God. He was obviously no sacerdotalist.” In all my studies of Cranmer, I have not come across this conclusion before. Do you have any sources for the assertion that Cranmer considered preaching more important than the Lord’s Supper administration? Did he ever say as much? Thanks Mark [11] Posted by Mark Carroll on 11-19-2008 at 06:46 AM · [top] I am not sure David that you have dealt with the rubric of the Order of the administration of The Lord’s Supper or Holy Communion from the BCP 1662 which clearly refers to administration by a Priest or with Articles XXIII ‘Of Ministering in the Congregation’ and XXXVI ‘Consecration of Bishops and Ministers’ which is carried through in the rest of the Articles XXX which make a clear distinction between administration by the priest and receipt by the laity. Whatever the reasoning, I do not see that Sydney’s little number can be claimed to be consistent with the BCP or Articles so is it worth considering again your position David notwithstanding all the enthusiastic people of the church in Sydney? [12] Posted by Pageantmaster ن on 11-19-2008 at 06:50 AM · [top] a few comments before I go to bed (and, no doubt, awake to find my inbox chokka block). Phil Snyder, I think the argument with respect to Tradition (since I’m sure you agree that Scripture is not broken with the move) is that of Article 34 - there is a need to change traditions to meet local circumstances as long as Scripture is not broken. Do you think that’s a fair reading of Article 34? Mark, thanks for the comments, I’ll take them on board. It does strike me, though, that to build in a difference between who may preside and who may preach is saying that there is a difference. Boring Bloke, I’m intrigued by your suggestion of a spiritual gift of presiding. Where in the Scriptures do you gain such an understanding? Also, I’m familiar with what Ignatius said - but Ignatius isn’t Scripture, is it? Pagaent - I think you strike at the heart of it. If there is any offence here, it is in the speed (relative!) of the move. That’s it, I’ll try and make some response tomorrow morning or, alternatively, just watch the discussion flow. One last thought - please remember this is an opportunity to understand better. As one of the commenters on this very thread once taught me in seminary - there is great value is seeking to be as sympathetic as possible to the position of those we instinctively disagree with. [13] Posted by David Ould on 11-19-2008 at 06:54 AM · [top] #13 David Sleep well, even if it is upside down. [14] Posted by Pageantmaster ن on 11-19-2008 at 07:17 AM · [top] #10: In the very act of setting them apart we are giving them a name, even if that name is just those authorised by the Bishop to preside at the Eucharist.’ #13 Sorry, I was a little hasty in writing that response. I probably used the wrong word, and should have written grace’ or character’ rather than spiritual gift.’ Of course your question still stands, but I’ll need to wait until I have enough free time to reply in detail. One question, though: if the essence of order is not directed towards the Eucharist, as claimed in your post, then what is it directed towards? In other words, how do you distinguish the order of the presbyter from deacon, lay, Bishop (or anything else)? [15] Posted by Boring Bloke on 11-19-2008 at 07:44 AM · [top] Please explain how this is any different than TEC consecrating a homosexual bishop. They also believed that they were following a “gospel imperative.” What is the point of having a communion if each part can go ahead and do its own thing? Haven’t we just spent five years dealing with the consequences of TEC using that line of thinking? [16] Posted by Ann Castro on 11-19-2008 at 08:23 AM · [top] subscribe [17] Posted by AndrewA on 11-19-2008 at 08:45 AM · [top] David, Scripture is indeed silent on deacons presiding at Holy Communion. But the Tradition is not. Can you show me where it is imperitive that deacons preside in Sydney? How is that local adaptation different from TEC’s statement that blessing same sex unions is imperitive in the USA? While I agree that TEC is violating scripture, you are violating tradition. Can you show the reason that these persons should not be ordained to the prebyteriat instead of simply licensed? It would accomplish the same end - providing enough people to preside at services of Holy Communion - and not violate the Tradition of the Church nor the character of the diaconate or laity. YBIC, Phil Snyder [18] Posted by Philip Snyder on 11-19-2008 at 08:48 AM · [top] I’m not certain of the word I want… Offense? Let’s go with that. The offense is not so much that “action x” has been taken, but that it has been taken unilaterally and under full knowledge that it could be a communion breaker for some. I can say the same thing about WO. Perhaps it may be found that it’s just and right for women to be presbyters. This decision, as with lay presidency, should be should be taken in council with, at the very minimum, all Anglican provinces. Preferably with the RCC and EO churches, too. It is fine for province Y to support decision X, but it is not fine for province Y to act on decision X until the rest of the communion is in agreement. Province Y’s job until the communion agrees is to lobby the other provinces and invite them into conversation. Province Y’s job is not to give the finger to its partners and do action X, anyway. As it is, WO came about because one small group of Anglicans decided to go ahead and do it. Then a larger, yet still local group, decided to affirm it. Finally, here and there around the world, we have entire provinces doing it “because they’re doing it over in that other province, so why can’t we?” Now it’s progressed to female bishops. And not only that, but female bishops forced upon everyone whether they like it or not, and objectors can just keep silent, thanks. Mark my words, lay presidency in 30 years’ time will be all over the Anglican world and in some places you’ll find it coming out of a vending machine. What Sydney has done may be, in the end, correct. How Sydney went about it, “Mind your own bloody business,” is entirely wrong and cannot be justified one iota as a communion partner. There’s an undercurrent of arrogance about acting on the decision, too. 2000 years of study, debate and agreement is being tossed to the wind like so much chaf. Apparently, those in Sydney are the only humans to have been blessed with a modicum of sense and can tell all the other Christians for the past 2 millenia how it’s supposed to be done. Again, taking the decision is one thing. Change can’t ever happen unless somebody takes a point that change is needed. However, acting on that change without consensus is arrogance at best, certainly heresy in the eyes of the rest of the church catholic, and apostasy at worst. Repent, Syndey, and hold off acting on this decision until the rest of the Communion agrees. Keep the decision. Delay action. My last observation is this: This is what we (the entire Anglican world) get when we put theological issues under the control of any group other than bishops. Laity in synod should be voting on budgets, mission, building, etc. Theology belongs in the councils of bishops. At this point, however, the idea of catholicity is all but abandoned in this “one catholic and apostolic church.” I doubt if the multiple genies can ever be put back into their bottles. [19] Posted by Antique on 11-19-2008 at 09:22 AM · [top] I am totally against lay presidency of the Eucharist, and I believe that Sydney’s decision was made arrogantly, without regard or respect for the rest of the communion. Their decision to go against church order is, to my mind, equally unorthodox as the decision to ordain practicing homosexuals. I do hope that Sydney will quickly see its error and change course. Please note that it does not matter that the Bible says nothing about who should preside at Holy Communion—what matters is that the Bible does talk about maintaining good order and protecting the faith. For that reason, we make sure that those who celebrate are called by God to that ministry, are well-trained and are approved by the Church for that role. We have set clear standards, and those who meet them are ordained to the presbyterate. Why would anyone short-circuit this centuries-old process? I suspect that, in the end, they have such a terribly low view of the Eucharist that they really don’t care about maintaining high standards for who celebrates. Sad that they also don’t seem to care about what everyone else in the Communion thinks. [20] Posted by Hindustaaniwalla Hatterr on 11-19-2008 at 09:30 AM · [top] I have nothing to add to what my brother Deacon Phil said other than my support for what he said. In the Tradition of the Church, deacons should be deacons until the Communion discerns otherwise. Thanks Phil for your thoughtful comments. [21] Posted by Capt. Father Warren on 11-19-2008 at 09:57 AM · [top] David writes: Boring Bloke, I’m intrigued by your suggestion of a spiritual gift of presiding. Where in the Scriptures do you gain such an understanding? Also, I’m familiar with what Ignatius said - but Ignatius isn’t Scripture, is it?David, I am sorry to pile on in what must be a disconceting conversation here. So you know where I am coming from, as a former Episcopalian now Eastern Orthodox, I am in essential agreement with Boring Bloke’s comments in #7. I am in fundamental disagreement with both the action and the theology of diaconal presidency not to mention lay presidency. That being said, to the point. Granted Ignatius of Antioch’s writing is not within the canon of Scripture as his writing clearly comes as a second generation of writers. Ignatius probably never met Jesus during his mortal life. He knew the apostles. He probably helped determine the Canon of Scripture. While his writings are not Scripture, they help determine what is. His writing is not Scripture ... neither is this decision on the part of Sydney. As your choices stand in opposition to those who defined the canon and in opposition to two thousand years of essential worship and teaching, the onus is on Sydney not only to show that such a choice is scriptural but why the worshipping Church for two thousand years has been wrong. Perhaps outward unity with the Christians who have been the Church for two thousand years (such as the Eastern Orthodox and Rome) is undesirable in Sydney but I tell you my own opinion: in this move to lay presidency, you set yourself apart from the Anglican Communion even as Plymouth Bretheren or Taize do. Whether this is not formally recognized by various “instruments of unity” or provinces is irrelevant. Equally importantly to driving the point home, IMHO you set yourself apart from those present here. God and I love Southern Baptists but we don’t have much to discuss aside from “Jesus loves me this I know for the Bible tells me so.” That is a wonderful thing but said quite shortly. [22] Posted by monologistos on 11-19-2008 at 10:23 AM · [top] Hmmm . . . the word is “prophetic,” isn’t it? Honestly, I think Sydney should pull out of GAFCON leadership until you all rethink, stop posturing, and start acting with (a) responsibility, given the situation in the Communion, and (b) Christian charity (something about “causing people to stumble” and “weaker brethren”, maybe you can help me remember those passages—and those even if you’re right, which you’re not). Aside from that, two critiques for David: (a) The reasoning on diaconal “administration” (“celebration” or presidency” would be more accurate, since “administration” implies something different for those of us who reserve) seems hollow. Lay baptisms are valid—in emergency situations for instance. Normative, no; valid, yes. Nobody has ever claimed otherwise. Likewise, at least in the Western tradition, marriage is actually celebrated between the couple: if my true love (of opposite gender—thought I should specify that given the current clime of the church) and I ended up alone on a desert island, with the intent to form a lifelong union we could marry one another, and any sexual relations would not be considered fornication—again, not normative, but still valid. The same is not claimed of other sacraments. By the rationale you cite here, you should also be advocating for diaconal ordinations, etc. Because either ordination is a sacrament, and deacons are to “assist” by “doing,” and should therefore conduct ordinations, or else it is something less than a sacrament and there was no good reason for restricting that function to one order in the first place. Or to put it succinctly, “assisting in the administration of” and “administering” are two different things, and the argument presented here doesn’t successfully get around that. (b) I find it ironic that you cite Cranmer, since that example is actually the exact opposite of your position. Yes, preaching is important (I would disagree that it’s more important than the Sacrament, but then I am unabashedly catholic—although I prefer to think of it as “correct” —and believe in a God who shows up and does things) but preaching does shape belief and is therefore important in guarding against heresy. Or, alternatively, it can lead people into heresy. One of the arguments I’ve heard several times for lay presidency is that the standards required for ordination are too high—but if people are well-trained enough to preach, why aren’t they well-trained enough to be ordained? By making this about “lay presidency” rather than ordination standards, it looks an awful lot like Sydney is just exercising itself in anti-catholicism (and fwiw—granted I wasn’t there—but the reports I heard sounded like Abp. Jensen was more interested in railroading GAFCON to hardline evangelical protestantism than in building bridges with catholics; or maybe, railroad bridges?). (c) Finally, I think you all (in Sydney) are ignoring the reality of the role of the priesthood as a sacrament—or, if you’re going to insist on reading more into the 39 Articles than is actually there, at least as a “sacramental”: a sign of the Church, a sign of the people of God, and therefore a sign of God himself, in the midst of society. I would think that this is intrinsically connected to issues of headship—and thereby, to issues of headship at the table. [23] Posted by tk+ on 11-19-2008 at 10:26 AM · [top] Oh, and David—uncritical acceptance of Newman is hardly a universal characteristic of Anglo-catholicism. He did, after all, get rid of the Vincentian Canon. Are you sure you’re not just playing him as a “went-to-Rome” bogeyman? [24] Posted by tk+ on 11-19-2008 at 10:28 AM · [top] monologistos, I think this Southern Baptist could share more with you than the simple love of Christ. In the Baptist Churches I’ve been in and part of the idea of ‘any member’ being able to lead the service of the Lord’s Supper would be thought utter rubbish. An ordained Preacher leads the Lord’s Supper. Some of the congregations might find a Deacon doing so ‘acceptable’, but only if they had no Preacher. The abscence of the Preacher would make preaching by the Deacon the ‘right thing’, but they’d just not hold the Lord’s Supper until they could ‘call’ another ‘preacher’. (I know the ‘oders’ within the baptist’s churches isn’t considered valid by the folks here. That’s not relevant to the Baptist’s own view of the limitions on who can preside. Even those of use who consider ‘ordination’ to be the laying on of hands by the congregations don’t support the idea of those who haven’t been so ordained leading in the Lord’s Supper.) [25] Posted by Bo on 11-19-2008 at 12:48 PM · [top] Innovation is to Anglicans what crack is to addicts. [26] Posted by Nikolaus on 11-19-2008 at 01:14 PM · [top] ‘any member’ being able to lead the service of the Lord’s Supper would be thought utter rubbish My observation growing up as a Baptist was that only a pastor or minister would lead Lord’s Supper, though beats me if anyone ever took the time to explain why. Most of the rare, once a quarter sermons involving the Lord’s Supper spent half the time denying any degree of sacramentalism. I’m curious as to whether Sydney has licensed female lay preachers or would be willing to license female lay presiders were they to actually implement these ideas. Unfortunately one of the side effects of this thread has been to add to my suspicion that the only theologically coherent options available to me are Baptist on one end and Eastern Orthodox on the other end, and, liturgical preferences aside, giving up all together on Anglicanism. [27] Posted by AndrewA on 11-19-2008 at 01:18 PM · [top] Very funny, but not true, Niklaus #26. [28] Posted by Theodora on 11-19-2008 at 01:24 PM · [top] The Big Fella’s Supper - Sydney style “Again after the Barbi he took the tinny and after saying good one mate he handed it round saying take a swig of this, this is good stuff and will do you good coz I made all the bad stuff go away. Do this loads to remember what a bonza thing I’ve done for you….........” [29] Posted by Pageantmaster ن on 11-19-2008 at 01:51 PM · [top] Bo #25, of course we do. But it is difficult to talk about things coherently because our vocabulary and contexts for theology and worship are quite different even though quite familiar in many instances. I may be wrong but it seems to me that if I have any purpose for seeking clarity here (in addition of course to being a witness in expressing my gratitude, praise and thanksgiving to our Lord), it is that I served about an Anglican altar for twenty five years before I became Orthodox over a decade ago. You soak quite a bit of visceral stuff through daily liturgical worship in but the interested churchgoer is likely to reference as a common vocabulary the ideas of men such as Phillips Brooks who writes of the preacher, “He come sout on to open ground. His work grows freer, and bolder and broader. He loves the simplest texts, and the great truths which run like rivers through all of life. God’s sovereignty, Christ’s redemption, man’s hope in the Spirit, the privilege of duty, the love of man in the Saviour, make the strong music which his soul tries to catch.”Men like F. P. Harton, Dean of Wells sharpen our understanding of ascetical theology. Our understanding of priesthood is deepened by the words of W.C.E. Newbolt, canon and chancellor of St. Paul’s Cathedral at Oxford who writes: S. Paul in this passage sets out with his own hand the distinguishing marks and characteristics of the priestly life. “You suspect me; you would pierce and shatter the shell which masks my life? Very well. This is what I am; attack this; penetrate here. It is the only defense I offer; what I strive to be in my ministrations, what by God’s grace I am.” So that we may almost say that we have in these verses a portrait of himself, by himself - a true speculum sacerdotum, into which a priest may look for instruction, guidance, and rectification of life; an ideal portrait of what a priest ought to be; painted, it may be, in strong colours, with features which stand out in high relief; a portrait neither attractive to look at nor easy to copy; a portrait at once unexpected in its details and startling in its suggestions. And yet, inasmuch as we believe, true; and further, deserveing of the most careful study in those who aspire to follow his footsteps, as the servants of God and instructors of men.”Without effort, the poetry of George Herbert informs our use of words even as much as the thoughts of John Cassian inform our theology and combine by God’s grace in the formed personality such that we are surprised and awed but not unmade when the Spirit edifies each man according to his capacity, revealing in glimpses the truth of what we proclaim of the Eucharist and of the Ekkelesia so gathered ... so that we might know the Lord more dearly and serve Him in our neighbor. I know there are holy men of wisdom in other traditions ... I’m speaking to something greater than a cultural affinity here; yet, it is not non-cultural either. The lights of Anglicanism cannot be reduced to something English or Protestant or evangelical or Catholic. They form an organic unity, miraculously uninterrupted by wars, death and all human failure ... not by leaping over intervening history but as pilgrims following Christ’s Way until God’s Kingdom comes. I would not see that proud church enter into a dhimmitude to the Zeitgeist. [30] Posted by monologistos on 11-19-2008 at 01:57 PM · [top] David Ould, forgive me if I have read your summary incorrectly. I think it says that the canon on deacon’s preaching was changed, so that the deacon no longer required the bishop’s authorization to preach. This is then what has caused people to think that deacons should be able to consecrate the communion as well. The one change justifies the other? And as to lay preaching and presidency in general, why? Does Sydney lack sufficient numbers of ordained men, so that the people are denied preaching and the sacraments? Surely “good order” which has been an Anglican hallmark calls for properly called and trained men to lead the people in hearing God’s Word and to administer the Holy Communion. I don’t see the need for these changes, barring emergency. [31] Posted by Katherine on 11-19-2008 at 02:08 PM · [top] Hello Rev. Ould. Although limiting presidency to the Priest or Bishop is not explicitly taught in Scripture—I certainly believe that it is the implicit teaching of Scripture as I believe that infant Baptism is implicitly taught (although going into this is more than I have time to do at this point—for that matter responding to any further posts may take more time than I have at this point). Further, the universal understanding of Scripture by the Church on this matter is authoritative for our understanding—as Cranmer likewise said regarding the definitive authority of the universal Church’s interpretation of Scripture (while speaking to the implicit Scriptural teaching of infant Baptism). Confutation of Unwritten Verities: Austen was more circumspect than to think, that any doctrine might be proved by use and custom without the Scripture. For baptism of infants he bringeth in this text, Except a man be born again of water and the Holy Ghost, he cannot be my disciple. And because the Donatists, like as the Anabaptists do now, wrest this to them that be of years of discretion ; against this exposition, he allegeth the manner of the Church in christening of infants. By the which he proveth that the Church hath alway taken this sentence, Except a man be born again, to be spoken also of infants. What manner of argument should this be of Austen ? The exposition of the Scripture, and the use of the sacraments, may be judged by the custom used in the holy Church alway : Ergo, the Church may make a new sacrament, and ordain any new article of our faith, without the Scripture. By the sentences before cited of Austen himself, it may be easily judged. I also grant, that every exposition of the Scripture, whereinsoever the old, holy, and true Church did agrec, is necessary to be believed. Blessings in Christ, William Scott p.s. Although I believe Scripture teaches that the Priest and Bishop are the proper administers of the Sacrament, I believe that the Holy Communion is not rendered empty or invalid simply because of a lack in the presider. I believe (as Luther and others have noted) that the Power of the Unfailing Word and Promise of God (particularly coupled with the prayers of His people) in the Celebration of Holy Communion overcomes any lack in the presider (as is the case in Baptism and the Reading of God’s Word, etc). And I certainly do not believe that the Lord fails to provide the Promised grace in Holy Communion (the grace of Holy Communion being “generally necessary for Salvation”) to the worthy recepient simply because of a lack in the presider. Gal 3:26 For ye are all the children of God by faith in Christ Jesus. 27 For as many of you as have been baptized into Christ have put on Christ. [32] Posted by William on 11-19-2008 at 02:21 PM · [top] Bo, as an example of talking different theologies, I understand that the Baptists (some/all?) consider themselves the inheritors of the Donatist tradition. I don’t want to make this into a tangent but the common criticism of Catholic “works righteousness” seems an oddly self-referential one in that context. Point being, while I don’t want to only emphasize in what way we are different, it is worthy of our attention to note that both TEC and the Diocese of Sydney are inclined to use theological words very differently than other Anglicans might. We will continue to talk past one another and to add to the chaos of the Tower of Babel if we fail to recognize this difficulty. We may, however, pray that the Holy Spirit grant us both the tongue and the ears to understand one another, that we may be one. [33] Posted by monologistos on 11-19-2008 at 02:22 PM · [top] Note: “Austen” in the Confutation of Unwritten Verities is Augustine [34] Posted by William on 11-19-2008 at 02:23 PM · [top] The concept of lay presidency is part of the same revising trajectory of which the Filioque, women’s ordination, LGBT ordination and marriage, are a part. The distinguishing note is that it’s pretty much an evangelical Protestant revisionist heresy lurking within a Catholic Body. [35] Posted by A Senior Priest on 11-19-2008 at 03:16 PM · [top] monologistos Yes, our vocabulary would initially be different, and there wouldn’t be a large number of Baptists that would be willing to spend the time to learn a common dialect. However, some of us are willing to make the effort (well, at least I try to be). The seminarians might consider themselves in the Donatist tradition. Those of us in the pews would only think that a ‘Preacher’ who lived contrary to the instruction of Scripture should be removed from the pulpit. We’d not count his soul as lost, nor would his ordination be removed, he would however suffer the baptist version of ‘inhibition’ or perhaps ‘deposition’. (I’m not 100% sure of the Donatist Tradition, perhaps I’ve made an icorrect correlation….) I’ve been concerned myself about the apparent intermix of ‘lay’ and ‘deacon’ in this discussion. Deacons in my ‘lexicon’ are ‘Ordained’, and hence not ‘Lay’. My attraction to the Anglicans started with the theology expressed in the Service for HM Charles I, King and Martyr. From that the expolation of the 39 Articles and the BCP 1662 followed. I can affirm all 39, love the wording and prayers of the BCP 1662 (so refined and so true!), and find the idea of a married male episcopate to be in accordance with Scripture. I now attend an Anglican (+Nzimbi) Wednesday service (when I can) in Glen St. Mary, Florida, though my Sunday Service is still with First Baptist, Macclenny Florida. [36] Posted by Bo on 11-19-2008 at 03:17 PM · [top] Hi David+, I agree with others here that Lay Administration does not conflict with scripture—nor is it necessarily consistent with it I might add, scripture is silent—and for that reason I am not prepared to break communion with Sydney over what I believe to be a disputable matter. I also agree that preaching is a means of grace to congregations. I do not say that preaching is more important than the eucharist but neither do I say it is less. I think they are vital for different purposes. My objection is more to do with the timing…whether the rest of the communion or Sydney represents the “weaker brother” in this instance I do not know, but it certainly seems an issue over which perhaps the conscience of others ought to have been a more pressing concern. [37] Posted by Matt Kennedy on 11-19-2008 at 03:26 PM · [top] AA, I’m blessed to be in a ‘high church baptist’ congregation (monologistos, I’ll try to explain the term in this context), the Preacher (dual PhDs) refers to the Lord’s Supper as a ‘mystery’ not a sacrement, and distances himself from ‘actual flesh’ being in the bread, and from ‘blood’ in the ‘cup’ (grape juice, not wine), but does say that nonetheless, in a mystery the Lord is present in the elements, as he is present in ourselves. He also stresses the danger to those who might partake unworthily (this is the basis for his ‘mystery’ as it is certainly more than mere memorial if it can cause sickness and death). monologistos . Some features of High Church Baptists: . Dedication of the Infants’ Parents. . Stained Glass with the Life of Christ portrayed. . Use of Advent Candles . Reading of the Scripture distinct from and before the start of the ‘Sermon’ (which is always on the Scripture read, though other Scripture passages and verses are often cited as well). . People stand for the Reading of the Scripture . Prayer inventing the Holy Ghost to superintend the messagenger, message, and people. . Deacons are not ordained until they have served a year in those duties as a ‘yolkfellow’ under the close supervision of the Pastor and an assigned Deacon. . No women in places of public service or authority in the Church. [38] Posted by Bo on 11-19-2008 at 03:33 PM · [top] Could I rephrase my post #1? I don’t even know what the Anglican Ordinal is. It can’t be very important in that wikipedia doesn’t have an article about it. (That’s a joke.) What does it say about the presidency of the Eucharist. [39] Posted by robroy on 11-19-2008 at 03:54 PM · [top] Half way through this argument, I was forcibly reminded of Bishop Michael Ingham. I think it’s around the “we’ve been discussing this for 40 years…long discussion, doctrinal justification…really we’re quite conservative” bit. Exactly what they say about same-sex blessing. No doubt Sydney thinks it is right, but then, so do New Westminster. Catholic Christendom, of which Anglicanism is a part, rejects this innovation. The Church does not approve it as consonant with Scripture interpreted by the Fathers, and neither does the Anglican tradition. If someone want to do it, feel free—there’s a Baptist church down the road. But Anglicans have never done this—if I’m wrong on that, I’d love to be corrected, but our conception of what Jeremy Taylor calls “the office ministerial” has always held up to me, and I’d be deeply uncomfortable with Sydney striking out on its own, especially after telling TEC and the Anglican Church of Canada to pull their heads in and consider the wider Church. I submit “Take the beam out of your own eye” applies. [40] Posted by Andrewesman on 11-19-2008 at 04:11 PM · [top] I find the attempts at theologizing a radically novel change in the way the Church from time immemorial administered the sacraments amusing, but ultimately unconvincing in the effort, but ultimately unconvincing. They remind me of something one of my heroes wrote, “I employed all the arguments of theology, which, when handled with a little judgement, are elastic to serve any purpose….” Charles Maurice, Prince de Talleyrand, twice a Bishop, Memoirs Vol 1, pg 41, Broglie ed. 1891 [41] Posted by A Senior Priest on 11-19-2008 at 04:13 PM · [top] Thanks all of you. Perhaps a further note of clarification before I head out on my day off. First, the question was raised over “arrogance”. I think that’s a big accusation to make and somewhat unnecessary. Sydney has been in large discussion with many African partners over this issue and has had a fair deal of success persuading them. I certainly sense a real concern here to do everything charitably and with the maximum partnership. To simply clal it “arrogant” is to be unaware of the dynamics. Next, someone asked about necessity. Two things have pushed us to this moment. First, we have taken the decision that men will only be ordained as presbyters when they are ready to lead whole parishes, not simply because it’s 10 months after their ordination as deacons. That has somewhat restricted the numbers. Second, the church is growing rapidly in many areas with deacons leading church plants and individual congregations. They are not able to preside and so our people are left without the sacrament - a situation which we consider regretable. Thus tyou have a push out of necessity, a clear evangelical conviction about the nature of ministry, and no obvious Scriptural impendiment. [42] Posted by David Ould on 11-19-2008 at 04:28 PM · [top] David, Is this then really about letting Deacons lead, not the unordained laymen? [43] Posted by Bo on 11-19-2008 at 04:31 PM · [top] David, isn’t the necessity somewhat artificial if it’s been created by delaying ordination? [44] Posted by oscewicee on 11-19-2008 at 04:45 PM · [top] Next, someone asked about necessity. Two things have pushed us to this moment. First, we have taken the decision that men will only be ordained as presbyters when they are ready to lead whole parishes, not simply because it’s 10 months after their ordination as deacons. That has somewhat restricted the numbers. So because of your voluntary self administered policy, you have a shortage, and now you are expecting the rest of the Communion to approve your innovations that are designed to address a self-created problem? That is a bit like the Big 3 US automakers unionizing themselves to death and then expecting the US taxpayer to bail them out. Easy solution: Curates. Second, the church is growing rapidly in many areas with deacons leading church plants and individual congregations. They are not able to preside and so our people are left without the sacrament - a situation which we consider regretable. Thes historic solution, very much consistent with Evangelical Anglicanism, was to have non-Eucharistic services when a priest was not available. Thus tyou have a push out of necessity, a clear evangelical conviction about the nature of ministry, and no obvious Scriptural impendiment. It is quite obvious to TEC that they have a Scriptural mandate for their innovations. And again: It is a self-created shortage, so pardon me if I’m not sympathetic. [45] Posted by AndrewA on 11-19-2008 at 04:50 PM · [top] Peter…thanks for a good essay. [46] Posted by mark harris on 11-19-2008 at 04:53 PM · [top] Bo, thanks for your info on “high church” Baptists - the largest Baptist church in my community would pretty much fit this description, but it’s something they’ve evolved to over the last 30 years or so. They recently took out their non-representational stained glass and put in, for instance, a Good Shepherd window. In addition to using an Advent wreath, they hold an Ash Wednesday service. I have wondered how much theology underlies these changes and how much is just a change in worship style, as it were. Are some congregationalist, non-liturgical churches growing back toward the church catholic? monologistos, thank you for your #30. [47] Posted by oscewicee on 11-19-2008 at 05:07 PM · [top] OK, having completely failed to do what I was meant to be doing today, I’ll add to my earlier comment and answer David’s question. First of all, some methodology, and unfortunately I’ve decided to pretend to be Richard Swinburne and adopt a probabilistic argument. Suppose that we are trying to judge whether some proposition T is correct upon which assessment we will perform action A. P(T) is the probability that proposition T is correct, based on the evidence available to us and P(!T) is the probability that it is incorrect. This probability is made from two factors: (1) There might be a specific and direct revelation concerning the matter at hand. the probability of this I label P(R); and it is related to the probability that the interpretation of the particular passage of scripture required to establish T is correct, or that the tradition of the church implies a uniform apostolic practice. P(R) does not mean that T is denied by scripture, only that there is no evidence. (2) there is background knowledge based on how likely T is given what else we know about theology (i.e. an argument applied from reason applied to other scripture). I label this P(I), and it is based on how firm the theological evidence for T is and how confidently we can apply it to the question of T. Thus P(T) = P(R) + P(!R)P(I|!R) if T is a positive proposition and P(T) = 1-P(R) - P(I|!R)P(!R)=P(!I|!R)P(!R) if T is a negative proposition (i.e. denying that a positive argument !T is correct), where I and R are in this case the probabilities for arguments supporting !T. If T is correct then pursuing A will lead to a series of benefits X_i, each with a probability of P(X_i) of occurring if we do a, and each giving a benefit B(x_i) (measured with respect to what would happen if we don’t do A). If T is incorrect, then a serious of (negative) consequences Y_i might entail, each with their own probability P(Y_i) and the weight given to each of these costs is C(y_i). For the purposes of simplicity I will assume that all the probabilities regarding the benefits and costs are statistically independent of P(T) and each other. Thus, to decide whether to proceed with A based on a negative proposition we need to evaluate the condition C=(P(!I|!R)P(!R)\sum_i P(X_i)B(X_i) > (1-P(!I|!R)P(!R))\sum_i P(Y_i)R(Y_i)) (This is essentially the same argument as Pascal’s wager, and, I think though I don’t know much about the subject, one of the fundamentals on which game theory is based). Now let’s apply this to the case of lay/diaconal presidency. This is a negative proposition since it denies the statement that only the Bishops and presbyters can preside that the Eucharist. Thus R and I are the probabilities given to the evidence supporting that only Bishops and Presbyters can preside, evaluated according to: scripture, right reason and tradition. I can see three benefits of the proposition: 1) it relieves pressure caused by a lack of presbyters (though this can be resolved by ordaining more people); 2) it removes doubt about certain matters of theology (though I am unclear that the theological concerns are correct); 3) it provides balance to the Anglican orders (though I’m not sure what this means). All of these benefits are small, for the reasons outlined in above posts. Now let’s look at the risks. 1) Invalid Eucharists will be performed; thus members of your congregations will not eat my flesh and drink my blood’ and therefore have no life in you.’ This cost associated with this risk is clearly very large, since it is a matter of salvation (given what is at stake, one might say close to infinite). You might say that this large cost depends on a Catholic theology which (being evangelicals) has only a small probability, but a small number times a very large number is still a large number. 2) There is the damage this will cause to the Anglican communion. This is (in my view) less important than the question of sacramental validity, but it is nonetheless very important. And the probability of it occurring if you proceed with A is surely close to 1. Thus the risks if you proceed with lay presidency are clearly substantially larger than the benefits, and you have to be overwhelmingly sure of your ground to go ahead. There may be other benefits/risks that I haven’t considered, but I think that I have covered the main points well enough to establish what I am trying to say. I’ll make a small digression by discussing the question of article 34 and whether the diocesan synod has the authority to make this judgment, which is an independent issue from whether the judgment is correct. The last paragraph states, Every particular or national Church hath authority to ordain, change, and abolish ceremonies or rites of the Church ordained only by man’s authority, so that all things be done to edifying. I agree with this statement. However, the issue of Lay presidency concerns the doctrines of the Eucharist, which was established by the Lord, and the question of the threefold order of ministry, for which a strong argument can be made to say it was either established by the Lord or by the apostles. By this article, a diocesan synod does not authority to change the ceremonies and rites relating to these doctrines. In fact, I would argue against an ecumenical synod having this authority. Now, back to my main argument, and an attempt to P(!I|!R), i.e. the probability that T is correct if there was no direct evidence; and this leads me into the doctrines of the Eucharist and spiritual gifts, since from Ephesians 4, Romans 12 etc we know that the various offices in the Church are associated with spiritual gifts, and I will here elaborate why I believe that the office of presiding at the Eucharist is associated with one of the gifts. I need to establish the probabilities of the various (popular) Eucharistic theologies.; and I will unashamedly base this on my own prejudices. I do not accept transubstantiation, partly because the articles tell me not to, but mostly because I do not believe that the Aristotelean metaphysics upon which it is built is correct (and the same goes for Wycliffe’s consubstantiation). I am also not a Zwinglian, because I cannot reconcile that doctrine with passages such as 1 Corinthians 11:27; 1 Corinthians 10:17, John 6:53,55, neither with the universal tradition of the apostolic fathers. That leaves me stuck somewhere between Luther and Calvin. However, I do accept Justin Martyr’s statement For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh. We do not permit just anybody to preside, so there must be something which sets apart those who are authorized to preside from those who are not. In other words, these people possess a power which those who cannot legally preside do not. Since the presider cannot change the bread and wine by his own power, and neither is it is an ability that we can in any way earn (Calvin forbid!), it must be given to the president by God through grace, and if given it follows by definition that it must be a spiritual gift or a imprinted character. This is what I meant when I used the term spiritual gift’ which I mentioned in my post above. I have not yet argued whether this spiritual power is given at Baptism, Confirmation, Ordination, or on another occasion. Another occasion seems quite unlikely, since I can’t think of any other possibilities; we do not let those newly baptized or confirmed preside, which implies that the power is given at ordination; and the ordination of the presbyter since only that service confers the right to minister the sacraments. In the next paragraph, I will discuss whether it is plausible that it is associated with the apostolic gift, which would mean that it is given at ordination. But first, we need to establish whether a gift is given. If Zwingli is correct, then there is no change in the bread and wine, and I do not believe that a gift is needed. If Zwingli is incorrect, and there is a change in the bread and wine, so that Christ is present in some way, whether substantial, spiritual or something else, then the probability that a spiritual gift or imprinted character is required to preside is very high for reasons I have given. Thus the probability that a spiritual gift is required for the ability to preside at the Eucharist is a little less than the probability that Zwingli is wrong, which I take to be very high. [48] Posted by Boring Bloke on 11-19-2008 at 05:10 PM · [top] I associate this gift with the apostolic gift mentioned in (for example) Ephesians 4. I cannot prove this, because scripture is silent on the matter, however I think that it can demonstrate that the apostolic gift is associated with various pseudo-sacraments in scripture; increasing the plausibility that it is also associated with the true sacrament of the Eucharist. For example, the ability to administer the spirit through the laying on of hands (Acts 8:17) is apostolic, and this power is not given to all the Baptized (Acts 8:18, OK I know that Simon Magus is not the best example, but still it establishes my point). There is the ability to forgive sins (John 20:33), to anoint the sick (James 5:14) - where it is expressly said that this should be done by the presbyters, to appoint for ministry by the laying of hands (2 Timothy 1:6 etc.), and, of course, one interpretation of scripture (given, e.g., in Aquinas) is that only those with the same office as those to whom Jesus said Do this in remembrance of me’ can actually do it. Thus I do not think it unreasonable from independent theology to say that there is a spiritual gift which enables one to preside over the Eucharist, specifically the apostolic gift. This is far from certain based on my argument so far, but the probability is still respectable. I cannot prove it from scripture, but it is consistent with what scripture says on other matters. Now I come to the question of the gift associated with the presbytery. First of all, we need to define what we mean when we refer to a presbyter. There seem to me to be four possible definitions: 1) We can say that the essence of the presbytery is directed towards the teaching ministry. 2) Directed towards the ability to preside at the sacraments, particularly the Eucharist. 3) Directed towards the pastoral responsibilities. 4) Directed towards leadership in a local congregation. (There may, of course, be other possibilities which I haven’t thought of, but I won’t list them because I haven’t thought of them). We have to choose one of these definitions as our starting point. Of course, if, for example, it can be shown that the teaching ministry is necessarily associated with the presiding ministry, and vice versa, then definitions (1) and (2) are equivalent, and either definition will lead to the same result. If they are not necessarily connected, then we cannot choose both definitions simultaneously, and this will mean that either some people can be (using the same example) teachers but not presiders, or some presiders but not teachers, or both. Your quest is therefore to pick one of these definitions, and demonstrate that it is not essentially linked with definition (2). In my earlier posts, I chose to define the presbytery in terms of option (2) (following Aquinas). Thus the question of lay presidency is for me a complete non-starter because I define the offices of laity and the deaconite as those not able to preside at the Eucharist.’ This definition is a perfectly reasonable starting point, and, it seems to me, perfectly consistent with both Roman and Anglican dogma. But presumably you adopt a different definition. You have explicitly denied option (1) in your post. Option (3) seems less plausible, since the lay and deacons also pastor. That leaves option (4), which at least has the authority of Peter to back it up: So I exhort the elders (πρεσβυτερους) among you, as a fellow elder (συμπρεσβυτερος) and a witness of the sufferings of Christ, as well as a partaker in the glory that is going to be revealed: shepherd the flock of God that is among you, exercising oversight, not under compulsion, but willingly, as God would have you; not for shameful gain, but eagerly; 3 not domineering over those in your charge, but being examples to the flock. 4 And when the chief Shepherd appears, you will receive the unfading crown of glory. You might say that Peter trumps Aquinas (and, unfortunately, you’re right), although as a matter of definition it is not so important: ultimately it doesn’t matter how we define the terms as long as we are self consistent and properly translate’ scripture into our own notation.’ Note that Peter claims to be a presbyter himself; which implies that Peter possess the spiritual gift which enables one to be a presbyter. This suggests (but does not prove, but none the less has a high probability) that since Peter possessed the apostolic gift that the presbyter’s gift is precisely this one (and, I think, this is strengthened by other evidence; also I am ignoring here the possibility that the distinction between Bishop and presbyter didn’t become important until the second century; which were I competent enough to present this argument properly I would have to do). Thus, even with this definition of the presbytery ministry, the probability is significant that both the leadership and presiding ministries are given by the same spiritual gift, that of the apostle. Thus P(I) is substantial whether or not there is direct revelation to support T; and P(!I|!R) is small, though perhaps not very small. As a digression, I note that if you adopt this definition of the presbytery, the question you should be arguing is whether (or not) the leadership within the congregation is equivalent to the ability to preside over the Eucharist; you spent your time addressing the issue of whether the teaching ministry is equivalent to the presiding ministry, which is utterly irrelevant to the question at hand. Now I need to assess the probability for T from direct revelation (P(R)). Scripture, as you well know, is silent on the matter of who can preside at the Eucharist. From this you might suppose that P(R) is 0. But there are other sources of revelation, even if they are not, as article VI and Luther’s principle insist, infallible. It is clear that the apostles would have given instructions based on Christ’s teaching to the churches they founded. Assuming that these instructions were consistent, and that they can be determined to at least a reasonable degree of confidence I hope that you agree that we should follow them because they come from Christ (or at worst the apostles). But no such instructions are recorded in scripture. The best we can do is attempt to work out what they were from the records of the post-apostolic churches. The practice of the early church seems to give clear and unanimous testimony: only those appointed to lead in the church can preside over the Eucharist. I cited Ignatius because he is one of the earliest examples, demonstrating that this teaching goes back to the time immediately following the apostles. But he is not the only example. The teaching is widespread, with notable dissenting voices. Can we be absolutely certain that this teaching is apostolic? No. Ignatius is, as you say, not infallible. It is possible that every church spontaneously decided at the close of the first century, despite having no apostolic precedent one way or the other (or a precedent to the contrary), to institute a rule that only the Bishops and presbyters could preside. It is, however, exceptionally unlikely. Thus the probability from revelation that the leadership office and the ability to preside at the Eucharist are equivalent, P(R), is very high, even though that revelation is recorded in the apostolic tradition rather than scripture. Thus P(!R) is exceptionally small, and P(T) = P(!R)P(!I|!R) is even smaller. Thus P(!T)= (1-P(T)) >> P(T). To return to the beginning, we have P(!T) >> P(T) and \sum_i P(Y_i) C(Y_i) >> \sum_i P(X_i) B(X_i). Thus P(T) \sum_i P(X_i) B(X_i) - P(!T) P(Y_i) C(Y_i) << 0, and proceeding with lay presidency is a big mistake. [49] Posted by Boring Bloke on 11-19-2008 at 05:10 PM · [top] [42] I appreciate the commitment to evangelism shown by the growth, but I can’t help but wonder if the whole controversy might have been avoided by the liberal procurement and distribution of tabernacles for storage, enabling continuation of the deacon’s mass. [50] Posted by tired on 11-19-2008 at 05:11 PM · [top] David Ould, The first point that strikes me is the presence in the sacraments of the epiklesis, which is not a component of the preaching. If the Eucharist were simply a memorial, I don’t think that lay presidency would constitute much of a problem. But, at least for those who can honestly be referred to as Anglo-Catholic, signifying belief in the True Presence of Christ, it is much more than a simple memorial. It is the means whereby Christ enters us and through which our sinful lives are transformed. Somehow, for reasons I cannot fully explain in words, it seems to me that this alone places it on a different plane (not necessarily higher, but separate) from preaching. Blessings and regards, Martial Artist [51] Posted by Militaris Artifex on 11-19-2008 at 05:37 PM · [top] I am put in mind of a ship of the Royal Navy, which, having no chaplain, the Captain read the service. He also pronounced Absolution. The Commander (Exec to us Americans) whispered that as he was not a priest, he could not absolve. On the Captain’s remarking, “oh, you’re right” the Chief Boatswain’s mate, in a focsle voice, announced to the crew, “Sins not absolved! Right turn! Quick march!”* Why would Sidney not just issue certificates to their deacons to the effect that they were to be considered as having been advanced to the priesthood? If they really think they can’t do that, they need to think some more about the whole thing. *from Fabulous Admirals, author on request [52] Posted by Ed the Roman on 11-19-2008 at 05:56 PM · [top] My questions in this are: 1. Is this a “may” (permission) issue or a “can” (able to) issue? both issues? 2. Would lay presidency bring into question apostolic succession? [53] Posted by Fr. Dale on 11-19-2008 at 06:19 PM · [top] Way to loose me after the first sentance, Boring Bloke. Got a way to express the idea in terms a history student can understand? [54] Posted by AndrewA on 11-19-2008 at 06:39 PM · [top] David Ould, I know the responses here are not comfortable and the message is not appreciative. Consider the distress caused by TEC’s unilateral innovations and ask yourself whether we should be acting likewise. Though I am persuaded otherwise, I do respectfully thank you for your conscientious work in laying out the Sydney argument.Regarding the Eucharist, for what it’s worth, the national canons of TEC still require a belief in the Real Presence in order for one to receive communion in the Episcopal Church. Not that those canons are respected by those who have set their face against the Gospel.Boring Bloke, your dispatches have greatly entertained me! My thanks. [55] Posted by monologistos on 11-19-2008 at 06:44 PM · [top] (e) When lay people are permitted to share in every form of ministry except one in the regular meetings of the congregation, except one, the impression can be given that the prohibited thing is the essence of ordained ministry. A sacerdotal view of the priesthood is difficult to avoid. Again this is a distortion of Anglican order due to the welcome developments in lay ministry which have not however been matched in the ministry of the Sacraments. From the Orthodox PoV, “the prohibited thing” - i.e., celebrating the Eucharist - is indeed the essence of the priesthood, just as the Eucharist is the essence of the Church. This is the ancient tradition of the Undivided Church, of which Anglicanism is an heir. Sydney’s proposed move can only serve to confuse (if not undermine) both the ecclesiology and the theology of holy orders in Anglicanism. Sydney wants to erase the traditional understanding of priesthood. But what do they propose to give us in its place? By taking away the defining characteristic of the presbyterate, they will make it redundant unless they give it a new definition. The resulting debate over 1) whether to abolish priesthood, and/or 2) how to redefine the priestly order could become the bloodiest battleground yet in Anglicanism. [56] Posted by Roland on 11-19-2008 at 07:25 PM · [top] oscewicee [47] Some is likely to be just ‘what the people want’. However, I’ve been blessed to be in such a church (though in different states, and counties) for all of the time I can remember, so I can’t directly speak to the ‘evolution’. I do know that the answer my current pastor had to the objection to the candles (by a former RC member) was “Rejecting Tradition has become our Baptist Tradition. We should be, rather than by our own habit and tradition rejecting ‘tradition’, instead looking to what the Traditional Aids to Worship sought to do, and if they sought proper ends, and did in fact help achieve them, and do not lead to conflict with the scriptures, embracing them.” After that encounter our (former) RC fellow mentioned Christmas Eve Mass, and guess what, our Baptist Preacher said ‘The Anglicans will be holding one. They’ll have a chamber group there to help celebrate, why not sit with me there?’ We don’t baptize babies (though my preacher sees it as ‘not harmful’), as baptism serves for us what confirmation does for most - the mark of entry into the local church communion. [57] Posted by Bo on 11-19-2008 at 07:27 PM · [top] Sorry, I should mention that the Christmas Eve service at the Anglicans was among the last service the Anglicans held in the building which is now Episcopalian (DNF - Howard). Not likely to be nearly so nice a service in the ‘rental place’ where we meet now. [58] Posted by Bo on 11-19-2008 at 07:30 PM · [top] Oh, yeah, one more thing (sorry) We are part of the catholic church, and so we are taught. By this I mean that in the lessons on how to spot a false “gospel”, the usefulness of the Nicene Creed as a ‘litmus test’ has been taught. We used a copy of it with the ‘Supporting Scriptures’ laid out, such that the charge of ‘creedalism’ could be countered. [59] Posted by Bo on 11-19-2008 at 07:36 PM · [top] #55—that’s one canon I have never heard of. I thought the only rule for receiving in TEC was that you be elegible to receive in your own Church! I admit I have never read the TEC canons in detail, but I have skimmed through them once in a while. Maybe you could explain why TEC canons always trump both the Bible and church tradition. The folks in Sydney need the same information. [60] Posted by GB on 11-19-2008 at 07:37 PM · [top] First, we have taken the decision that men will only be ordained as presbyters when they are ready to lead whole parishes, not simply because it’s 10 months after their ordination as deacons. In Orthodoxy, we make a similar distinction in a different way. We have gradations within each of the three orders. Anglicanism has maintained a special status for archbishops within the episcopacy. In Orthodoxy we also have archpriests within the presbyterate. As I understand it, most priests are eventually elevated to archpriest, but only after they have demonstrated maturity and leadership. [61] Posted by Roland on 11-19-2008 at 07:38 PM · [top] When Jesus breathed the Spirit (John 20:21-23) onto the Apostles and then gave the Apostles the power to bind and loose (Matt 16:19/18:18) He did not breathe the Spirit or give powers to the 4000 or the 5000 and he had opportunity and obviously being God, the power to do so but he did not. He gave the charism to the Apostles and they in turn laid hands on Timothy, by way of the power to bind. This is the plain read of Scripture and it has no room for what has been twisted into the present suggestion. God has chosen the few or one for specific purposes many, many times. God chose the Jews not the Egyptians he chose prophets far and few in between, he choose Apostles not the entire town of Galilee. All the one Holy and Catholic Church has recognized and honored this from the Apostles forward except the extremists of the Reformation and now Sydney. Lay presidency overthrows Christ’s ordaining of his apostles and giving them the power to govern and guide the Church with the guidance of the Holy Ghost. WO led to VGR and broke the Communion what will the fallout be from this foolishness? The whole idea behind WO is there is no difference between gender and gifts of the HG or roles in the Bible and this is the basis of the homosexual argument and it is dead wrong (pun intended). Arrogance has been rightly discussed in other posts and I would like to flesh it out a bit and say that Sydney has chosen to not only to ignore the Patristic Fathers, all of the faithful for centuries, the Roman and Orthodox Communions, but in my view the Holy Ghost as well as defy Christ’s direct founding of his priesthood in Scripture. Have we forgot the Epistle to the Hebrews with Paul speaking of our Great High Priest? The Order of Mechelzidek? If there be A high priest it only follows there be a priesthood. The denial of the work of the Holy Ghost in all the Church is what is spectacular about this claim. Thank God for Sydney to finally get it right after 2000 years of failure. I wish I could have been there to see the Holy Ghost finally descend after being 2000 years late. The priesthood has been bound by the Church by the successors to the Apostles and has continued under the guidance of the Holy Ghost. There can be no Communion with the unlawful. It was unlawfulness that brought us to our present predicament and this innovation will lead to further chaos. It demonstrates the weakness of the Gafcon coalition and it demonstrates the common cause partners may not have as much in common as was thought. Someone mentioned the Baptist preoccupation with preaching against what they realized they had thrown out and now must twist and sway to justify. When the Methodists figured out what they had done they wanted to make it right: “Wesley in his “Korah” sermon, scathingly censured those who would depart from the Apostolic Order, and Dr. Coke, one of the first Superintendents, as they were then called, of the Methodists in this country, made proposals to Bishops White and Seabury, that he and Mr. Ashbury (the resident Methodist Superintendent) should be consecrated Bishops, and proposed a reunion of Methodists and Churchman on a basis conceding a reordination of their ministers.” Grafton Is this what lies in store for Sydney? Can we never learn but chase after every clanging cymbal? Canst thou, O Sydney, bind the sweet influences of Pleiades, or loose the bands of Orion? Job 38. [62] Posted by Just Wondering on 11-19-2008 at 07:43 PM · [top] Meant to say “Laid hands on Timothy and others” such as is my typing in a hurry. [63] Posted by Just Wondering on 11-19-2008 at 07:58 PM · [top] David, I thank you for posting this piece on Sydney’s consideration of lay presidency, given the seriousness of the issue as it pertains to the present and future unity of orthodox Anglicans, and I wish I had time to write a more comprehensive response. But let me, at least, offer a few thoughts, beginning with the Articles of Religion and the 1662 and 1552 Ordinals. XXIII. Of Ministering in the Congregation. It is not lawful for any man to take upon him the office of public preaching, or ministering the Sacraments in the Congregation, before he be lawfully called, and sent to execute the same. And those we ought to judge lawfully called and sent, which be chosen and called to this work by men who have public authority given unto them in the Congregation, to call and send Ministers into the Lord’s vineyard. The article is wonderfully Elizabethan in its use of language, and perhaps not as direct (or circumspect with regard to the potential for misinterpretation) as one might be in writing a confessional statement, church canon, or policy today. However, the article is saying that only those who are lawfully called and sent may engage in preaching or ministering the sacraments in a congregation, and that only those who have public authority to call and send Ministers into the Lord’s vineyard can do this calling and sending. In other words, this is talking about ordination. How can we be sure it is talking about ordination? Because of the way those who wrote the Articles applied them. The uniform practice of the Church from that time to the present was that the Ministers (clergy) did the preaching and the administration of the sacraments. (See “Article XXXVI Of Consecration of Bishops and Ministers” where the context demonstrates that here and in every instance in which the term “Ministers” is used in the Articles, it means the clergy, functioning in such manner as pertains to their order.) Regarding the application of these Articles, we notice this language from the 1662 ordination service from the Deacon: The Bishop says. IT appertaineth to the Office of a Deacon, in the Church where he shall be appointed to serve, to assist the Priest in Divine Service, and specially when he [i.e., the Priest] ministereth the holy Communion, and to help him in the distribution thereof; and to read Holy Scriptures and Homilies in the Church; and to instruct the youth in the Catechism; in the absence of the Priest to baptize infants; and to preach, if he be admitted thereto by the Bishop. And furthermore, it is his Office, where provision is so made, to search for the sick, poor, and impotent people of the Parish, to intimate their estates, names, and places where they dwell, unto the Curate, that by his exhortation they may be relieved with the alms of the Parishioners, or others. Will you do this gladly and willingly? Answer. I will so do, by the help of God. Further, note these differences in the services of ordination for a deacon and a priest: (From the Ordination of a Deacon) Then shall the Bishop deliver to every one of them the New Testament, saying, TAKE thou Authority to read the Gospel in the Church of God, and to preach the same, if thou be thereto licensed by the Bishop himself. (From the Ordination of a Priest) Then the Bishop shall deliver to every one of them kneeling the Bible into his hand, saying, TAKE thou Authority to preach the Word of God, and to minister the holy Sacraments in the Congregation, where thou shalt be lawfully appointed thereunto. (These words are virtually unchanged from the earlier 1552 book, favored by many evangelicals.) Most significantly, perhaps, in the Preface to the Ordinal we read: IT is evident unto all men diligently reading holy Scripture and ancient Authors, that from the Apostles’ time there have been these Orders of Ministers in Christ’s Church; Bishops, Priests, and Deacons. Which Offices were evermore had in such reverend Estimation, that no man might presume to execute any of them, except he were first called, tried, examined, and known to have such qualities as are requisite for the same; and also by publick Prayer, with Imposition of Hands, were approved and admitted thereunto by lawful Authority. And therefore, to the intent that these Orders may be continued, and reverently used and esteemed in the Church of England, no man shall be accounted or taken to be a lawful Bishop, Priest, or Deacon, in the Church of England, or suffered to execute any of the said Functions, except he be called, tried, examined, and admitted thereunto, according to the Form hereafter following, or hath had Episcopal Consecration, or Ordination. Finally, XXVI. Of the unworthiness of the Ministers, which hinders not the effect of the Sacraments. ALTHOUGH in the visible Church the evil be ever mingled with the good, and sometime the evil have chief authority in the ministration of the word and sacraments; yet forasmuch as they do not the same in their own name, but in Christ’s, and do minister by His commission and authority, we may use their ministry both in hearing the word of God and in the receiving of the sacraments. Neither is the effect of Christ’s ordinance taken away by their wickedness, nor the grace of God’s gifts diminished from such as by faith and rightly do receive the sacraments ministered unto them, which be effectual because of Christ’s institution and promise, although they be ministered by evil men. Nevertheless it appertaineth to the discipline of the Church that inquiry be made of evil ministers, and that they be accused by those that have knowledge of their offences; and finally, being found guilty by just judgement, be deposed. From this Article we see three things: 1. the Sacraments have an effect; 2. unworthiness of the ministers does not diminish or hinder that effect, and 3. the sacraments are administered by the ministers. Another thread on Stand Firm dealing with this issue is entitled: Dan Martins on the Sydney Stance: Evangelicals to Liberals: “Psst! Meet Me in Back of the Barn”. And there is one sense in which I fear this comparison of Sydney Evangelicals with western Liberals is apt: Both seem to be saying (1.) “we know more about how the church should function than our Anglican forebears did” and (2.) “we believe that what we are doing (be it lay presidency or same sex blessings) is a ‘Gospel imperative’.” While the Diocese of Sydney asserts that its position is based on a Gospel imperative,” it does not actually or convincingly demonstrate how that is so. There is also a tendency in the Sydney position to attribute too much to the bogeyman of Anglo-Catholicism and a supposed sacerdotal conception of the priesthood, when all we are really talking about is Church order as it has been traditionally understood by Anglicans and as reflected in the 1552 and 1662 Book of Common Prayer. If we wish to remain consistent with the 39 Articles as an expression of our Anglican identity, the burden of proof must fall on those who wish to implement lay presidency to show that laity or even deacons were ever authorized to administer the Lord’s Supper. And, if the language I quoted from the Preface to the Ordinal is correct, it cannot be shown from the Scriptures or the whole history of the Christian Church that this was ever the case. Robert S. Munday Nashotah House I also blog at To All the World and Anglican Revivalist [64] Posted by ToAllTheWorld on 11-19-2008 at 08:01 PM · [top] Back when I was still an Anglo-Catholic (less than two years ago), one bit of my stock rhetoric was that Anglicanism, unlike Lutheranism and Calvinism, did not have an eponymous founder; we were not Cranmerians. It would appear that Sydney disagrees with me on this point. So, perhaps, when they are booted from the communion, they can style themselves after the pattern of the ELCA as the Evangelical Cranmerian Church in Australia! But, seriously, Anglicanism as it is now constituted is not the church of Cranmer. That church came to an end with the accession of Queen Mary in 1553. Anglicanism as we know it was founded under Queen Elizabeth. The underlying principle of the Elizabethan Settlement was that Englishmen of both conservative (High Church) and reforming (Puritan) tendencies should find in Anglicanism what they deemed essential to Christianity, and that they should be able to worship as Anglicans in good conscience. The Puritans had to put up with a lot of stuff they would rather have jettisoned, and the High Churchmen were deprived of many things they would rather have retained. But most could live with the result, however grudgingly. There have been recurring attempts by the Puritan faction to overthrow the Elizabethan Settlement. But their attempts to do away with the episcopate and the prayerbook have been consistently rejected. It appears to me that Sydney is trotting out the Puritan agenda for another go. This time, instead of attacking the episcopate directly, they are trying to undermine the lower orders by erasing the distinction between deacon and presbyter. But if they succeed you can be sure they will go for the episcopate next. [65] Posted by Roland on 11-19-2008 at 08:16 PM · [top] #64 Dean Munday - thank you for setting that out. #65 Roland - I am not sure that you are right about the disjunct you see between the Church of Edward VI and Cranmer and the Church of Elizabeth I, James I and VI and Charles I. There were certainly developments but I am very uncomfortable with the idea I hear from Americans that the Elizabethan Settlement was some sort of anything goes free for all. If you actually read the Prayer book and Articles they are quite clear and rather strict. You also have to remember that in England they had [and to some extent still do have] the force of law. [66] Posted by Pageantmaster ن on 11-19-2008 at 08:50 PM · [top] There is an excellent online version of the BCP 1662 including the Articles here thanks to Lynda Howell in case it is helpful [67] Posted by Pageantmaster ن on 11-19-2008 at 08:55 PM · [top] Pageantmaster [65], I’m American and see a disconnect between the CoE pre and post Mary I, while not at all seeing the origin and current development of the Anglican Communion/Church as being a ‘lawless free-for-all’. HM Henry VIII was a Roman Catholic in Schism. HM Edward VI (and/or his regents) were most certainly NOT Roman Catholics. HM Mary I was a Roman Catholic. HM Elizabeth I brought about the ‘find accommodation within the bounds of Scripture’ solution. As some one else pointed out on this board, both of the ‘extreme edges’ of Religious thought of the time had to accept less than they wanted in the the newly re-established independent national Church. HM Charles I, II and James II & VII wouldn’t have been at all comfortable with the Edward VI CoE. (The later of course wasn’t ‘comfortable’ but was able - at first anyway, to ‘accept’ the Established Reformed Catholic Church) Had the HM Edward VI version of the CoE been restored on the accession of HM Elizabeth I, the Sydney ‘Anglicans’ would likely have become the norm within the ‘Established Church’. [68] Posted by Bo on 11-19-2008 at 10:25 PM · [top] For those wishing to do the morning, evening prayers from the BCP 1662, and the night prayer in traditional language, the http://www.oremus.org/cofe.html website is great! [69] Posted by Bo on 11-19-2008 at 10:30 PM · [top] David+ (particularly in reference to 42, but also in general) By what Scriptural imperative was it determined that all priests must be rectors? This seems the heart of the issue. Here in N. Michigan, we have priests underfoot all over the place, because the ordain almost anyone who volunteers. I would stipulate that any of Sydney’s deacons, and quite probably many potential lay presiders would have better credentials than some of the priests here. But, the logic of your argument seems to hinge on the “necessity” of lay presiders because only those who are prepared to lead entire congregations (ie- rectors) may be priests- which is certainly outside of all Tradition as I know it. One would think that if it were good enough for Cranmer, it would be sufficiently Protestant for most Anglicans. It clearly writes off Anglo Catholics. I do not see that any of us would ever knowingly receive Communion from a layman, and I am unclear as to what degree of even synodical relationship could be maintained, although, of course, I would cede the floor on that to Bishop Iker or Bishop Ackerman. [70] Posted by tjmcmahon on 11-19-2008 at 10:48 PM · [top] Hi #68 Bo It is quite helpful to read Queen Elizabeth’s Act of Uniformity by which she restored the work of her brother including the Prayer book very deliberately here. Thanks for your reference in #69. [71] Posted by Pageantmaster ن on 11-19-2008 at 10:49 PM · [top] For many of us, the defence of diaconal and lay presidency or administration of Holy Communion comes out of left field. I think David Ould is warning us, especially those of us committed to the GAFCON movement, not to jump to condemnation before we talk with brothers and sisters in Christ (see JD clause 12). Of course, the same could be said of the Anglicans in Sydney. They say that their decision is the fruit of a thirty-year argument and synods that predate GAFCON. I find that only partially satisfying, and it almost looks like they wanted to let the horse out of the barn before the issue could get to a wider forum. In any case, diaconal presidency is now a “fact on the ground” like women’s ordination. I also think we need to beware jumping to draw a moral equivalence between the actions of Sydney synod and those of TEC. They are right to say that there is no clear command in Scripture as to who presides at the Communion, whereas the Bible is full of normative statements and commands on marriage and sexuality, which TEC has brazenly contravened. Having said that, their decision is a major breach of catholic order and the practice of the Church of England and Anglican Communion. The burden of defence is on them, in my opinion. I have received the book The Lord’s Supper in Human Hands: Who Should Administer?, a series of essays by John Woodhouse, Mark Thompson, Peter Bolt, Bp. Glenn Davies, and Robert Tong (of these, Bp. Davies is not actually arguing for the change theologically but only legally in terms of an Appellate Tribunal decision in the Anglican Church of Australia). I am working on a review of this book, but I do want here to note that it seems to put forth different and possibly contradictory arguments for the new practice. The first argument, forwarded primarily by Dr. Woodhouse, is that it is an evangelical mandate. He writes: “We cannot be content with practices which obscure or distort the gospel” (p. 7), and he then lists 5 distortions: 1. That exclusive clergy presidency suggests a “power” which a lay person cannot have; 2. That higher qualifications are required for presiding than preaching (the comparison with lay preaching is a recurrent theme); 3. That the validity of the sacrament depends on the person presiding; 4. That ordination has more to do with the Sacrament than preaching (see #2); 5. That a priest is essential to the Lord’s Supper and no other practice. This then leads him to identify the traditional practice with the BCP’s warning against “things that at first were of godly intent and purpose devised, and yet at length turned to vanity and superstition.” So the argument would seem to go like this: • Evangelical Christians must uphold the gospel. • There is no basis in Scripture for priest-only administration of Communion • There are historical developments in the idea of priestly power that raise the Sacrament over the Word. • Therefore it is a gospel mandate to change the practice. However, Sydney’s defenders also seem to argue that priestly presidency is an “indifferent” matter, not commanded in Scripture and therefore subject to local option. Hence the reference to Article XXXIV. Woodhouse himself seems to concede that the traditional practice is not essentially contrary to Scripture but only that it has been distorted. He argues that the Reformers’ insistence on priestly presidency was a pragmatic, “quality control” decision, due to the shortage of educated church leaders (p. 11). Frankly, I think the Reformers, and not just the Anglican ones as Robert Munday points out, had stronger reasons for believing in “orders” and corresponding duties of those orders. Some of their stance may have reflected the hierarchical worldview of their day, but some of it is of permanent and biblical character. This issue, like that of women’s ordination (which curiously is bound up with it, as female deacons in Sydney may now preside!), is a major challenge to ecumenical discussion within the Fellowship of Confessing Anglicans. It may be that certain convictions held by members of FCA are “incoherent” as Dr. Radner has recently asserted (though I think he might reflect on the coherence of his own church before he criticizes others). But before we throw in the towel, let’s listen to what each other is saying. That is the freedom we have in Christ and cut loose from the byzantine politics of TEC. Even within Sydney, I think there are those who believe this decision is mistaken (the book refers to arguments made by Abp. Donald Robinson but unfortunately I could not get access to his articles), and others like Abp. Jensen are aware of its potential to distract from the wider Gospel mandate for a “Global Anglican Future.” So as we used to say in TEC, let’s continue the dialogue. [72] Posted by Stephen Noll on 11-19-2008 at 11:18 PM · [top] I read the act a bit differently… ....Be it therefore Enacted by the Authority of this present Parliament, That the said Statute of Repeal and everything therein contained, only concerning the said Book and the Service, Administration of Sacraments, Rites, and Ceremonies contained or appointed in or by the said Book shall be void and of none effect, from and after the Feast of the Nativity of Saint John Baptist next coming. And that the said Book with the Order of Service and of the Administration of Sacraments, Rites, and Ceremonies, with the Alterations and Additions, therein added and appointed by this Statute, shall stand and be from and after the said Feast of the Nativity of Saint John Baptist in full force and effect according to the tenor and effect of this Statute; Any thing in the aforesaid Statute of Repeal to the contrary notwithstanding…. ....and the Form of the Litany altered and corrected, and two Sentences only added in the delivery of the Sacrament to the Communicants…. Changes to the Litnay and the Sacrament. Not quite her brother’s book… (the And the real “kicker” ... Provided always, and be it Enacted, That such Ornaments of the Church and of the Ministers thereof, shall be retained, and be used, as was in this Church of England, by Authority of Parliament, in the second Year of the Reign of King Edward the Sixth, until other order shall be therein taken by the Authority of the Queen’s Majesty, with the Advice of her Commissioners appointed and authorized under the Great Seal of England for Causes Ecclesiastical, or of the Metropolitan of this Realm. And also, that if there shall happen any Contempt or Irreverence to be used in the Ceremonies or Rites of the Church, by the misusing of the Orders appointed in this Book, the Queen’s Majesty may, by the like advice of the said Commissioners or Metropolitan, ordain and publish such further Ceremonies or Rites as may be most for the advancement of God’s Glory, the edifying of his Church, and the due reverence of Christ’s holy Mysteries and Sacraments…. Whereby her Archbishops really brought the Church into her customary ‘Rule by halves’. Of Course the most wonderful BCP had to wait for the Restoration…. [73] Posted by Bo on 11-19-2008 at 11:22 PM · [top] I think Deacons doing the Lord’s Supper is OK in some of the other provinces already (++Nzimbi allows it I think….) [74] Posted by Bo on 11-19-2008 at 11:28 PM · [top] I’ve found it very interesting to follow this thread and the overwhelming number of responses opposed to “Lay Administration”. I think at best it shows many with a deep affection for the Anglican ethos, and a desire for there to be no further fracturing amongst those of us who call ourselves orthodox Anglicans. What I do find a little disturbing is the blurring of weight and authority, in regard to what is and what is not suitable justification for one’s position. One commentator spoke eloquently of Ignatius and many others concerning the differing versions of the BCP. Yet I’ll throw in Jerome and my favorite version of the BCP, that allows for expanded lay administration, (IMHO)and we’re back to square one. If we cannot arrive and agree upon what is and is not authoritative, then we are doomed to forever “box our own shadow”, as we slip further and further into irrelevance in the eyes of the world. Another concern is that everyone is so interested in getting their point across, that no one is addressing the underlying issue… that in several places around the world, in addition to Australia, that there is a serious lack of trained or mature mentors to disciple and serve new converts to the faith. If we insist upon the “Anglican way” then some of you are going to have give up your six figure salaries , and go into the bush to serve these areas newly opened for the Gospel. I believe that an Equitable distribution of Priests and Bishops could put this issue to rest. Who wants to sign up first. [75] Posted by Abishai on 11-19-2008 at 11:36 PM · [top] Get me through the process, and I’ll take the Job. Mind the ‘discernment’ might be a hurdle (I may carry too much Baptist Baggage), and the ‘seminary’ I can’t afford, and I’m remarried (though my first divorce was ‘for cause’, and I the ‘innocent party’).... [76] Posted by Bo on 11-19-2008 at 11:40 PM · [top] OOPS, I don’t have six-figure salary to give up. (I don’t think that’ll hurt my chances though, I’m sure the poor can serve the poor….) [77] Posted by Bo on 11-19-2008 at 11:41 PM · [top] On a more ‘authoritative point’ isn’t the 1662 to BCP of GAFCON? [78] Posted by Bo on 11-19-2008 at 11:42 PM · [top] Robroy #39, the “Ordinal” is found in the Prayer Book, in the 1928, beginning at page 529. Reading through the services for ordaining deacons and priests in that Prayer Book makes the distinctions between the offices of Deacon and Priest very clear. It seems to me that Sydney has created this dilemma for itself. It has changed the priesthood to include only those who are capable of being Rectors, eliminating assistant priests, and it has changed the Deacons’ responsibilities, and, finding itself without sufficient qualified clergy under its new system, now needs to consider having men who are deacons or unordained do what priests have done before. The simple solution would be to change back to the original system, making Deacons people who help the Priest and assist the poor and Priests be men fully authorized by ordination to preach on their own steam and to consecrate the Holy Communion. These functions are very clear in the traditional Anglican Prayer Book. [79] Posted by Katherine on 11-20-2008 at 02:05 AM · [top] Prof. Noll (Steve - #72), I was not aware of the book The Lord’s Supper in Human Hands: Who Should Administer?, though I will make certain to obtain a copy. But from your itemization of the points in the book, I would like to offer a response. 1. That exclusive clergy presidency suggests a “power” which a lay person cannot have; No, clergy presidency suggests a function to which a lay person is not called. 2. That higher qualifications are required for presiding than preaching (the comparison with lay preaching is a recurrent theme); In Acts, Stephen and Phillip (both deacons) were obviously preachers; and Phillip baptized the Ethiopian eunuch—whether it was a case of necessity, or whether deacons routinely baptized, we are not told. However, there is no scriptural evidence for diaconal or lay presidency at the Lord’s Supper. And the early Fathers, who were in the best position to observe how the Scriptures were applied in the matter of eucharistic presidency, always considered it reserved to the presbyterate. 3. That the validity of the sacrament depends on the person presiding; The validity of the sacrament depends on the authority of the person presiding, which is made clear in the Preface to the 1662 Ordinal (quoted in my post above [#64]). 4. That ordination has more to do with the Sacrament than preaching (see #2); Our Anglican forebears were almost equally restrictive regarding preaching as they were the sacraments. Only clergy were to preach. It was to be done primarily by presbyters and only secondarily by deacons who had been licensed by the bishop. The fact that laypeople may be articulate teachers and speakers on many occasions and at many types of Christian gatherings does not mean that they should assume the function of the preacher in congregational worship. If someone shows that kind of calling to the task of preaching, the Church should ordain him. But (speaking hypothetically), if ordination did have more to do with the sacrament than with preaching, so what? It would be a matter of a calling to a function rather than elevation to a position of power. In Article XXXVI. Of Consecration of Bishops and Ministers, the writers seem to have anticipated the concern that ordination created a special priestly caste: The Book of Consecration of Bishops, and Ordering of Priests and Deacons… doth contain all things necessary to such Consecration and Ordering; neither hath it any thing that, of itself, is superstitious and ungodly. In other words, one need not worry that the making of bishops, priests, and deacons is, in and of itself, a cause of superstition or ungodliness—though it often seems to me that members of the Sydney diocese view it as precisely that. 5. That a priest is essential to the Lord’s Supper and no other practice. A physician is essential to the practice of medicine, and an electrician is essential to wiring a house. But both are pretty much interchangeable with any other individual, other than when they are exercising their respective callings. It is a matter of function. But what if priests (due to their being set apart for a particular function in the church) were more essential to the sacraments than any other function? So what? This seems to spring more from a superstitious aversion to clergy and sacraments than anything that is grounded in Scripture, Anglican tradition, or even sound reason. I agree that we need to dialogue very earnestly with our brothers and sisters in Sydney about this. I merely pray that they do not do something unilaterally that jeopardizes the unity of an orthodox Anglican entity before it even gets off the ground. [80] Posted by ToAllTheWorld on 11-20-2008 at 02:31 AM · [top] AndrewA, #54 On reflection, I made a few errors in my initial paragraph (treating various probabilities as statistically independent when they are not; not counting the cost to the communion if Sydney go ahead and are right in their theology). I could also have done (or more likely others who actually agree with the theology I was trying to justify could have done) a better job of trying to justify catholic theology from scripture in the middle section of my post. That’s what you get when you try to write something as lengthy as that at 10:00 at night without time to properly review it. The argument can probably be amended to correct these errors. But my main point, which I think stands despite my numerous shortcomings, was that the costs if you have got your theology wrong (and the catholics right in their view of the sacraments) are too large and the benefits of proceeding (since you can just ordain lots more presbyters which also solves the problem, and nobody would have an issue with that) too small and the chance that this theology is right (i.e. in agreement with what Christ told his apostles to establish in the churches they founded) too low (seeing what is what is written in the church fathers - we are sola scripture not solo scripture, therefore we must give some weight to other sources of authority where they do not contradict scripture, including the fathers, and additionally that there is a small (we’re evangelicals, after all) but non-zero possibility that the catholics have correctly interpreted scripture in this matter) for this action to be worth taking. Was that any easier to understand? [81] Posted by Boring Bloke on 11-20-2008 at 05:02 AM · [top] Thank you Stephen, for your words. You’re right that we need to work harder to understand each other. As for others - I’m tempted to try and answer observations but questions that I’ve raised so far don’t get much of an answer. I also get the feeling that making the post itself is controversial enough! I may just let you all run on some more while answering specific points of query. To that end: tjmacmahon (#70): You would have to ask the Archbishop! However, I think the intent was to put some more meaning into the term “presbyter” (elder). Mark Harris (#46) - I think you have confused with the clone. RobRoy (#39)- the ordinal is the ordination service I’ll go on providing clarifying answers, if necessary. [82] Posted by David Ould on 11-20-2008 at 06:00 AM · [top] A lot of folks quoting the Articles for and against but unless one can prove that the authors of the Articles (which are not Scripture) would have approved of an ordinand being a woman or that a lay man could preside at the Eucharist your only superimposing your own agenda over what they have said. In other words your putting words in the mouths of the dead who obviously cannot answer and that is an easy thing to do and will only convince those who are immature in the faith. The Scripture is clear as that no one but the Apostles was given power to loose and bind to forgive or not forgive sins and to pass on this charism. John 15:16 “Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you”. Mark 3:14 “And he ordained twelve, that they should be with him, and that he might send them forth to preach, And to have power to heal sicknesses, and to cast out devils:... and after the Apostles are named the passage goes on to say ... “And if a kingdom be divided against itself, that kingdom cannot stand”. That an argument that Scripture is silent seems mightily strained and very dangerous to me. [83] Posted by Just Wondering on 11-20-2008 at 09:06 AM · [top] David, “tjmacmahon (#70): You would have to ask the Archbishop! However, I think the intent was to put some more meaning into the term “presbyter” (elder). “ If you are going to use an opinion (that presbyters MUST be rectors) as a linchpin of your case, you need to be able to support it on Scriptural grounds. The Archbishop is not immediately available to me as a reference. You might at least have been good enough to cite some available reference to support your argument. Certainly, one cannot overthrow 2000 years of church tradition on the basis of a whim of an archbishop, a whim that apparently his deacons are not prepared to defend, or even define. [84] Posted by tjmcmahon on 11-20-2008 at 09:10 AM · [top] #84 TJ Agreed The whole point about having curates in training posts is to give ordinands on the job experience under more experienced priests. If they are not unutterably hopeless they will likely move on to have their own parish. The fact that Sydney have decided to hamstring themselves in this peculiar way and not give the newly ordained the opportunity to gain by working with more experienced priests before flying solo is hardly a persuasive argument, but what do I know? [85] Posted by Pageantmaster ن on 11-20-2008 at 09:20 AM · [top] sorry that should read the newly ordained rather than ordinands. [86] Posted by Pageantmaster ن on 11-20-2008 at 09:23 AM · [top] I’m starting to think that Anglicans need something like the Precautionary Principle of international law, so that an innovation like this would require consensus among the provinces. [87] Posted by tired on 11-20-2008 at 11:28 AM · [top] In very few words: This Sydney innovation makes no sense whatsoever. It has no sufficient support from any Scriptural, theological, historical, traditional, communion, or reasonable perspective. The argument is far from convincing. This continual piercing of the body of Christ with wounds from a thousand cuts is very painful, frustrating and heart breaking to me. I am sure I am not alone in this thought. I have spent the better part of this morning reading this and the postings and the more I read the more I keep asking myself “what was/is Sydney thinking?” This is sad, very sad indeed. Fr. Kingsley Jon-Ubabuco [88] Posted by Spiro on 11-20-2008 at 12:45 PM · [top] #62 Best comment on this thread. Well said. [89] Posted by evan miller on 11-20-2008 at 01:34 PM · [top] Boring Bloke, et al: Your mathematical (?) chain of reasoning left me with a swirling head. I’m not a math person. After reading through most of the comments, my attention span was used up so I jumped down here to add my bit. 1) After witnessing Anglican highjinks for more than 30 years, I reached a “plague on all your houses” position. I decided for myself that my understanding of the Eucharist would be: the sacrament is effected entirely by God the Holy Spirit. No man (or woman) has any inherent or delegated spiritual power to effect it, ordination notwithstanding. 2)Ordination confers authority to celebrate the Eucharist within the jurisdiction of the ordaining authority. It is a matter of permission or authorization, not of charism. 3)This point of view does not exclude lay-celebration, as distinct from lay administration of the Sacrament to communicants. Lay celebration (presidency) is a matter of consent by Authority and the congregation being served. 4)None of this is very Anglican, or Catholic, or Eastern. It is basically a Protestant view which regards the grace of the Sacrament as given by God and the Presider merely ministers it to the people and himself. They are all receivers, the Lord is the only giver. 5) After seeing the shenanigans of too many in Holy Orders, I have come to doubt that there is anything such as a charism of Orders. I see it as a matter of church order and administration, the Church human. Burn me at the stake if you must, but I will remain always: Dumb Sheep. [90] Posted by dumb sheep on 11-20-2008 at 02:59 PM · [top] dumb sheep As you say, “None of this is very Anglican.” [91] Posted by evan miller on 11-20-2008 at 03:22 PM · [top] Dr. Noll, So as we used to say in TEC, let’s continue the dialogue. And in the meantime? The “and” is missing from your statement. Did you mean to say: 1. So as we used to say in TEC, let’s continue the dialogue and in the meantime, put a moritorium on this practice until it is settled. 2. So as we used to say in TEC, let’s continue the dialogue. and in the meantime, Syndey can do whatever Sydney decides is right and others can hop onto that wagon if they wish as we continue our dialog. 3. So as we used to say in TEC, let’s continue the dialogue and [something else]. Do you have an opinion as to what should be status of Sydney’s active practices during the dialog? I’d like to hear it. I’m on record as seeing it needs to cease immediately and not resume until there is consensus for it from the Primates or Lambeth (and preferably with the RCC and EO). [92] Posted by Antique on 11-20-2008 at 04:01 PM · [top] The “let’s dialog” remark sent the hair up on the back of my neck. Thanks Evan I am glad you got the point even with the grammatical errors! I was in a hurry. I suppose that if our “Great High Priest” “ordaining” his Apostles giving them power and Spirit is not convincing enough as to who who preside at the His Eucharist than surely we can not condemn flying an airliner into a building because there is nothing in Scripture proscribing such an action. [93] Posted by Just Wondering on 11-20-2008 at 10:32 PM · [top] Dear Antique, I was not being flippant in suggesting we continue the dialogue, though I was contrasting the true meaning of the phrase with the manipulative way it has been used in TEC. I think diaconal presidency is a fait accompli for the moment in Sydney and maybe in some other places in the Anglican Communion. There is nothing “we” can do about it. There is not even anything the Archbishop of Sydney can do about it in the short run. In this regard it is a lot like women’s ordination elsewhere. The difference is this. Those who have promoted this practice in Sydney believe it is in accordance with Scripture and not at odds with classic Reformed Anglican teaching, and they have now put forth their reasons in all seriousness (available so far as I can see only through the Anglican Church League). I think they are mistaken and that a large majority of Anglican Evangelicals (and others) would disagree with them. However, the issue has been localized in Sydney, and Sydney itself has seen itself on the periphery of the wider Communion, even among the churches of the Global South. With the entry of Abp. Jensen and others into the GAFCON movement, that position on the fringe is changing, though some in that diocese are acting as if it weren’t. What Sydney does now matters to Uganda and Nigeria and many others in the Fellowship of Confessing Anglicans. The positive news is that the FCA has a substantive basis (the Jerusalem Declaration and the authorities it recognizes) and a body (the Primates Council) by which its members can deliberate on issues of importance to the wider church. I hope and trust that biblically and historically informed arguments to the effect that this innovation is unwarranted may be presented to the promoters in Sydney. But to do this one needs to understand their position. I believe that in the long run they will conclude either that this is a misreading of God’s will in Scripture and history or at least that it is an indifferent matter whose time has NOT come. In the short term, I think the Archbishop will prevent the diocese from authorizing lay presidency and the practice by deacons will be limited. (David, any statistics on how many deacons there are, how many are leading congregations, and what the male/female breakdown is?) So this is what I mean by continuing the dialogue. The appearance of this issue is not only a public relations problem for FCA (see Graham Kings), but an initial test as to whether the GAFCON movement is prepared to practice what it preaches (again I cite JD clause 12). Because the issue is inter-connected with other questions of ecclesiology, such as the ordination of women and the nature of the 3-fold order of ministry, I think it is an opportunity as well as a threat. [94] Posted by Stephen Noll on 11-20-2008 at 10:33 PM · [top] Dr Noll, I was not being flippant in suggesting we continue the dialogueI didn’t think you were and I meant not to covey such. It was a legitimate question. I agree, the dialog must be taken. But there remains the deed to be dealt with while dialoging. I simply wanted your view on that point. Thank you for the further thoughts but I gather you decline to comment directly, otherwise I missed your pointed response. No reason you should have to give a direct reply to the likes of me, but I was rather hoping for some insight from a senior cleric elsewhere in the world. What ++Jensen may likely do, whether it’s a challenge to GAFCON, etc., is all good commentary and I find myself agreeing with most of it. But as to what you think Sydney should do while that dialog is continuing? Stop? Carry on? It’s obvious Sydney will carry on. But like ordaining non-celibate gays to the episcopate, or WO, or easy divorce and remarriage, or supporting abortion on demand, or denying the Trinity, etc. ... while the talks are continuing, what is your opinion on a moritorium? Or perhaps I’m putting you on the spot and you’d rather not answer. I can understand that. But I value input from senior clerics far more than my own input and most of the commenters here. I’d love to hear what PB Schori thinks. What the GS primates think. What Rowan thinks. What every bishop and dean thinks. You’ve volunteered some interest in this thread so I thought I might get you to weigh in on enforcement, the lack of which has permitted us to get to the stage we are in the AC. Should Sydney police itself until the all-clear is given at a future date? Not “will,” as I think we can be assured they won’t, but “should?” And thank you so much for your time, futher response forthcoming or no. [95] Posted by Antique on 11-21-2008 at 12:45 AM · [top] Stephen (#94) I can’t give overall statistics. My ordination grouop this year contained 49 deacons, of whom 5 were female. That was the largest ever in Sydney. I don’t think any of the women had anything other than a conservative stance on the WO question and I don’t think many of them will even want to preside. the current policy of reassessing the presbyterate has only been in place for a few years so the number of deacons is low, relative to presbyters. This is bound to change in the future. I, for instance, have every intention of remaining where I am for the foreseeable future (ie not seeking arectorship elsewhere) and so have little likelihood of being ordained to the prebyterate. It seems common sense to us that I should expand my role to mirror that of my senior minister. That’s how it seen down here. [96] Posted by David Ould on 11-21-2008 at 03:13 AM · [top] I suppose that if our “Great High Priest” “ordaining” his Apostles giving them power and Spirit is not convincing enough as to who who preside at the His Eucharist than surely we can not condemn flying an airliner into a building because there is nothing in Scripture proscribing such an action. I don’t disagree with your point, but I also don’t think that this is the best example. Exodus 20:13 Thou shalt not kill’ comes to mind. And, depending on the circumstances, Exodus 20:15 Thou shalt not steal’ might be relevant as well. And if you are thinking of flying your own unmanned aircraft into your own unoccupied building, I’m sure there is something in scripture warning against excessive stupidity. Sorry, this post doesn’t have a much of a link to the diocese of Sydney. (Unless there is something else we should be worrying about.) [97] Posted by Boring Bloke on 11-21-2008 at 04:16 AM · [top] While perceived suitability for incumbency has been accentuated of late in Sydney as a leading criterion for presbyteral ordination, matters aren’t quite as hard and fast as some might infer from this. Some lucky parishes here still enjoy the odd curate or two; also, there doesn’t seem to be anything which stops rectors from, say, moving back into chaplaincy when that is mutually deemed expedient. [98] Posted by Michael Canaris on 11-21-2008 at 04:54 AM · [top] David remarks: It does strike me, though, that to build in a difference between who may preside and who may preach is saying that there is a difference. Well, of course there is, and there always has been in Anglicanism. Although Morning Prayer in the 1552 BCP assumes a priest will be present (though not necessarily presiding at the service), the 1662 book (and the US 1928 book) distinguish carefully between “minister” and “priest”, and indeed in the tradition of the Church a head of household may preside at a service of Morning or Evening Prayer for his family. But he may not pronounce absolution; that is reserved for a priest, according to the rubrics—as is presiding at the Eucharist. The “sacerdotal priesthood” is part of what Anglicanism is. If you want to be Presbyterians or Methodists, that’s fine and God bless you. But please don’t try to pretend that Cranmer would approve; I at least am completely fed up with this sort of special pleading and spinning to justify doctrinal innovation. [99] Posted by Craig Goodrich on 11-21-2008 at 05:43 AM · [top]
I suppose that if our “Great High Priest” “ordaining” his Apostles giving them power and Spirit is not convincing enough as to who who preside at the His Eucharist than surely we can not condemn flying an airliner into a building because there is nothing in Scripture proscribing such an action. I don’t disagree with your point,
I do! Where does one find Jesus “ordaining” his Apostles (and the word was used specifically so I am intrigued as to where it is derived from? Then, how does one go from there to establish that Jesus intended only Presbyters and not Deacons to administer communion? It seems a fair stretch to me. [100] Posted by David Ould on 11-21-2008 at 06:00 AM · [top] The “sacerdotal priesthood” is part of what Anglicanism is. On the contrary. Cranmer took an entirely Reformed position: XXVIII. Of the Lord’s Supper. The Supper of the Lord is not only a sign of the love that Christians ought to have among themselves one to another, but rather it is a Sacrament of our Redemption by Christ’s death: insomuch that to such as rightly, worthily, and with faith, receive the same, the Bread which we break is a partaking of the Body of Christ; and likewise the Cup of Blessing is a partaking of the Blood of Christ. Transubstantiation (or the change of the substance of Bread and Wine) in the Supper of the Lord, cannot be proved by Holy Writ; but is repugnant to the plain words of Scripture, overthroweth the nature of a Sacrament, and hath given occasion to many superstitions. The Body of Christ is given, taken, and eaten, in the Supper, only after an heavenly and spiritual manner. And the mean whereby the Body of Christ is received and eaten in the Supper, is Faith. The Sacrament of the Lord’s Supper was not by Christ’s ordinance reserved, carried about, lifted up, or worshipped. XXXI. Of the one Oblation of Christ finished upon the Cross. The Offering of Christ once made is that perfect redemption, propitiation, and satisfaction, for all the sins of the whole world, both original and actual; and there is none other satisfaction for sin, but that alone. Wherefore the sacrifices of Masses, in the which it was commonly said, that the Priest did offer Christ for the quick and the dead, to have remission of pain or guilt, were blasphemous fables, and dangerous deceits. That’s a pretty obvious rejection of sacerdotalism. I really appreciate the discussion above on the distinction between Presbyter and Deacon, but let’s not pursue the old chestnut of how Cranmer was really a sacerdotalist. The evidence just won’t support it. [101] Posted by David Ould on 11-21-2008 at 06:11 AM · [top] I have to say David that from what you say part of this has come about from problems caused by the growth of Sydney and a consequent shortage of the ordained [We should be so lucky!]. I have followed and been impressed by the Connect ‘09 aims and materials for spreading the Good News. If the problems do result from this and the pressures then I would have thought the simple answer is to ordain the diaconate as appropriate rather than making it dependant on incumbancy which is a real novelty to me, when the rest of the church is moving towards seeing mission as not bound to parishes and traditional forms of geographical limitation. I would have thought with your training you should finish the job and equip yourself as God has called you in all the fullness of the laying on of hands and commissioning to administer all the sacraments [as the Articles make clear they are]. I suppose Sydney is in the position of TEC when the rest of the Communion said “Please don’t do this”. Well we know what the Americans did. I would like to think that Australians were capable of better. God bless in your calling to mission and thank you for this enlightening thread. PM [102] Posted by Pageantmaster ن on 11-21-2008 at 06:18 AM · [top] thanks PM. I can’t say, personally, that I’m massively happy with the new distinction here between deacon and presbyter, although I appreciate what they are trying to achieve. However, I don’t think that the argument re Diaconal Administration hangs on it. Rather, it has precipitated it. I am satisfied that it would be right for a deacon to preside, even if we didn’t have the current issue here and questions of timing not withstanding. [103] Posted by David Ould on 11-21-2008 at 06:33 AM · [top] OK, David #101, I’ll head in again, and try not to embarrass myself further. When I wrote I don’t disagree with your point’ I should have written I don’t challenge your point which is a closer representation of my view. I guess that your reply is still I do.’ But in any case, I think that the link is derived from the theology of the absolution (and giving of the spirit by the laying on hands) and the Eucharist. In both the absolution and the Eucharist, the presbyter or Bishop is said to be speaking in persona Christ, as shown by the use of the first person in the words of institution This is my body.’’ In both the administration and the laying on hands the presbyter is asking for one of the persons of the Trinity to come onto a material object, either the spirit onto the believer or the son into the bread or wine (in a spiritual sense, of course, to be consistent with Cramner). Thus the same processes are involved, which means that it should be restricted to the same people. Is this argument completely convincing? Not in my view; it contains a couple of assumptions and extrapolations which I have not been able to establish in my thoughts on the subject; and it also needs to be demonstrated that these gifts are given to the apostles alone (Acts 8 is a good place to start for the laying on hands). But it does seem to me to be very plausible; and I challenge you to disprove this theology (or better, the theology as described by somebody who actually understands the Catholic position rather than as described by a self-confessed theological ignoramus such as myself) from scripture. [104] Posted by Boring Bloke on 11-21-2008 at 06:51 AM · [top] Though admittedly getting a Calvinist like David Ould to admit that there is a small possibility that one small part of Catholic doctrine that stands in his way may be correct is probably about as likely as getting the pope to say That]http://www.zenit.org/article-24302?l=english”]That is why Luther’s expression “sola fide” is true.[/url]’ [105] Posted by Boring Bloke on 11-21-2008 at 07:49 AM · [top] I should of course preview my post before publishing a link. [106] Posted by Boring Bloke on 11-21-2008 at 07:51 AM · [top] David, We all have our theological outlook which shapes our reading of scripture. And part of the beauty of Anglicanism is that it allows for Sydney type evangelicals and Anglo-Catholics to be part of the same Communion. But the real issue in this debate isn’t whether you have biblical or missional warrant for your actions. The issue is whether you are going to continue to submit to catholic order or break from it. If you refuse to turn back from the outcry of the majority within the Communion (i.e., place your theological outlook above the catholic order of the Communion), you had better be prepared to say that this is a defining issue of the faith, i.e., that the substance of Christianity is at issue. (Which obviously places an incredible burden of proof on Sydney). If not, you are acting in a schismatic fashion by turning your back on the rest of the Communion over a matter that is not essential to biblical faith. The real issue here is not biblical faith but catholic order. Does Sydney respect catholic order or not? Without catholic order, we cease to be Anglican in any meaningful sense, and the Anglican Communion is truly doomed…no effort to reform it is possible. My prayer is that GAFCON will move swiftly to overturn this threat to catholic order from the right with as much determination as it has done so to overturn the threat to both catholic order and biblical faith on the left. Discipline is essential if we are to become a faithful witness to Christ as a Communion. The left’s action may be more abhorent, but the right’s action may be even more destructive in that it divides us over matters that are not essential to the faith. Please do not go the way of sectarianism! Uphold the Nicene Creed, and maintain your allegiance to the one, holy, catholic and apostolic Church. [107] Posted by Rob Paris on 11-21-2008 at 10:09 AM · [top] There is an ontological difference between a Deacon and a Priest. The Bishop lays hands on a Deacon and recognizes that person’s calling to be a unique ministry of service to God and the Church. A Bishop and other Priest’s assembled lays hands on a Priest creating a person whose unique calling is to serve God and His people through their leadership, pastoral ministry, teaching and preaching, and in the confecting of the Sacraments. The three-fold order of clergy in the Church has been around for a very long time: please consult the Acts of the Apostles. If a Deacon wishes to celebrate the Mass, then that Deacon should discern his calling to the priesthood according to the canons of his diocese and seek ordination from his Bishop. Once again, it seems that the personal desires and wants of a few are dictating far reaching and massive changes in tradition and theology for the many. The tail continues to wag the dog. [108] Posted by Sacerdotal451 on 11-21-2008 at 01:10 PM · [top] On “sacredotal priesthood” the Anglican Reformers certainly denied the “sacredotal priesthood” they saw in the “Romish Sacrifice of the Mass.” But they also affirmed the “Eucharist Sacrifice” in the sense the Church Fathers laid out—citing the teaching of the Church Fathers as the true Scriptural teaching on the matter. As Bishop Jewel stated to the Roman Catholic Harding on the matter of “Eucharistic Sacrifice” in his Defense of the Apology: We deny not but it may well be said, Christ at His last supper offered up Himself unto His Father; albeit, not really and indeed, but, according to M. Harding’s own distinction, in a figure or in a mystery; in such sort, as we say, CHRIST was offered in the sacrifices of the old law: and as St. John says, The Lamb was slain from the beginning of the world. “As for our part,” St. Augustine saith, “Christ hath given us to celebrate in His Church, an image or token of that Sacrifice for the remembrance of His Passion.” Again he saith, “After CHRIST’S ascension into heaven, the Flesh and Blood of this Sacrifice is continued by a Sacrament of remembrance.” Eusebius saith, “We burn a Sacrifice unto GOD, the remembrance of that great Sacrifice upon the cross, and CHRIST commanded us to offer up a remembrance of His death, instead of a Sacrifice.” It were an infinite labour to report all that may be said. To be short, St. Hierome saith, turning himself unto CHRIST: “Then shalt Thou, O CHRIST, receive Sacrifice, either when Thou offerest up Thyself for us unto Thy Father,” (which was only upon the cross,) “or else, when Thou receivest of us praises and thanksgiving.” St. Cyprian saith, “We offer the LORD’S cup,” meaning thereby, the wine contained in the cup. So likewise St. Augustine saith: “The Church offereth up the Sacrifice of bread and wine.” If there be any darkness in this manner of speech, both St. Cyprian and St. Augustine have plainly expounded their meaning. St. Cyprian, in the same Epistle before alleged, saith thus: “The cup is offered in remembrance of CHRIST: by the wine CHRIST’S Blood is shewed, or signified: therefore wine is used, that by wine we may understand the LORD’S Blood: water only without wine, cannot express the Blood of CHRIST: in the water we understand the people: in the wine CHRIST’S Blood is represented: in all our Sacrifices, we work the memory of CHRIST’S passion: the Sacrifice that we offer, is the Passion of our LORD.” Thus much St. Cyprian in the same epistle. St. Augustine saith, “In this Sacrifice is a Thanksgiving, and a remembrance of the Flesh of CHRIST, that He hath offered for us, and of the Blood of CHRIST that He shed for us.” Thus saith St. Cyprian: thus saith St. Augustine: thus say the old godly learned fathers of the Church of Christ. [Of course someone can produce numerous quotes from the English Reformers strongly denouncing the “Romish Sacrifice of the Mass” (which, of course, is the case)—But this is beside the point. The point is that the English Reformers held the truth of the “Eucharistic Sacrifice” as laid out by the Church Fathers.] Finally, there is the related issue (in regards to both the “Eucharistic Sacrifice” and the lay and diaconal celebration of the Eucharist), which I raised above. That is, the traditional Anglican position on submission to the real (though secondary) authority of “tradition.” As Cranmer stated clearly in his Confutation of Unwritten Verities: I also grant [with St. Augustine], that every exposition of the Scripture, whereinsoever the old, holy, and true Church did agree, is necessary to be believed. And Canon 6 from the 1571 Bishop’s Convocation which ratified the 39 Articles (and this Canon affirm the truth of the 39 Articles and the 1559 Prayer Book and Ordinal immediately after this statement—thus showing that the Anglican Formularies are necessarily intended to be understood in accordance with the teaching of the “Catholic fathers and ancient bishops”): Preachers shall behave themselves modestly and soberly in every department of their life. But especially shall they see to it that they teach nothing in the way of a sermon, which they would have religiously held and believed by the people, save what is agreeable to the teaching of the Old or New Testament, and what the Catholic fathers and ancient bishops have collected from this selfsame doctrine. [Again, someone can produce plenty of quotes regarding the vastly superior authority of Scripture over any single Church Father, etc (which I certainly agree with, by the way) or condemnations of the “vain traditons of men”—But this is, again, beside the point, because: 1. The universal understanding or interpretation of Scripture by the “Catholic fathers and ancient bishops” is clearly not being counted here among the “vain traditions of men” by the English Reformers, and 2. The secondary authority of the Church Fathers or “tradition” in comparison to Sacred Scripture’s inerrant and infallible witness of the Apostolic faith is already understood.] Blessings in Christ, William Scott Gal 3:26 For ye are all the children of God by faith in Christ Jesus. 27 For as many of you as have been baptized into Christ have put on Christ. [109] Posted by William on 11-21-2008 at 02:49 PM · [top] p.s. Just to know where I’m coming from in the above comments—I’m not an “Anglo-Catholic” (although the term is used so elasticly that I don’t know if that actually matters)—although I certainly hold “catholic” doctrines such as the Creedal doctrine of Baptismal regeneration taught in the BCP—namely that “it is certain by God’s Word, that children being Baptized have all things necessary for Salvation and be undoubtedly saved” 1552/1559 BCP. Simply put, I take seriously the Anglican principle of the “catholic faith” stated by Bishop Jewel in his Apology of the Church of England—regarding the central authority (though of course secondary to Sacred Scripture) of the patristic faith of the “old Catholic Fathers”: “We have returned to the Apostles and the old Catholic Fathers. We have planted no new religion, but only preserved the old that was undoubtedly founded and used by the Apostles of Christ and other holy Fathers of the Primitive Church.” Blessings in Christ, William Scott Gal 3:26 For ye are all the children of God by faith in Christ Jesus. 27 For as many of you as have been baptized into Christ have put on Christ. [110] Posted by William on 11-21-2008 at 04:01 PM · [top] During the first fifty to one hundred years, I imagine that there were a multitude of instances where ‘lay’/ordinary folk who ‘led’ groups in sharing the Lord’s Supper. [111] Posted by Bill C on 11-21-2008 at 04:09 PM · [top] Bill C. “During the first fifty to one hundred years, I imagine that there were a multitude of instances where ‘lay’/ordinary folk who ‘led’ groups in sharing the Lord’s Supper.” I think the operative word here is ‘imagine’. That means that you are guessing that it happened but you have no evidence that it did happen. I think this is a great discussion on the topic of Lay Presidency and only wish that it had taken place before the fact not after the fact. Those that have initiated lay presidency have failed to honor their brothers and sisters in the rest of the communion. They have failed to discern the body. [112] Posted by Fr. Dale on 11-21-2008 at 05:37 PM · [top] thanks all for the latest posts, received overnight. Let me just take up what BoringBloke had to say (#104) But in any case, I think that the link is derived from the theology of the absolution (and giving of the spirit by the laying on hands) and the Eucharist. In both the absolution and the Eucharist, the presbyter or Bishop is said to be speaking in persona Christ, as shown by the use of the first person in the words of institution This is my body.’’ I think the counter would be to show that at the Supper the President speaks in the third person of Christ, as he clearly does. Indeed, I would argue that the absolution is a higher moment in the service than the Supper. It is, pardon the term, a “raw” gospel moment. The promises of the gospel have been read, explained and affirmed, sin has been confessed and now forgiveness is announced. In a sense, the gospel is cystallised at that moment. Whereas at the Supper we are remembering that gospel event. It is subtley different. No less important, of course, but one is dependent upon the other. It’s also interesting to note that the absolution is the only part of the communion service that the rubrick requires the bishop, if present, to speak to (to be fair, he is also required to give the final benediction). Again, that’s not an argument for Diaconal presidency, but it goes towards seeing what Cranmer prioritised in the service. As for the matter you raise of Anglo-Catholics being welcome in the Communion - I wouldn’t want to add more than the piece from Richardson that I originally cited (all of it - I have only cited a couple of sentences directly pertinent to the point I was making at the time). That’s not meant to be confrontational, rather to express the honest tensions that many of us, on both sides of the discussion, feel. [113] Posted by David Ould on 11-21-2008 at 05:53 PM · [top] David, “Indeed, I would argue that the absolution is a higher moment in the service than the Supper” Could you clarify what you mean by using the word “higher”? Absolution deals with forgiveness of sins. The Supper is communion with Christ Himself. [114] Posted by Fr. Dale on 11-21-2008 at 06:38 PM · [top] sure, my fellow Deacon… I would question the way you phrase your question and the assumption within it. “Communion” is not somehow placing us closer to Christ than a simple response to the gospel can. Indeed, it is interesting that the BCP consistently speaks of the Lord’s Supper, not “Communion”. Here is my understanding (which I have set out elsewhere) of what is going on in that section of the service. The confession and absolution come prior to the supper and provide the grounding for it. If there is a highest “gospel moment” in teh service it is that point, for that is where we see the essence of the gospel - confession, trust in Christ and forgiveness. From there we move to a remembrance (so the continuous usage of the words in the prayer of consecration) of what Christ achieved for us on the cross. Having established our right status in front of God, we are strengthened by feeding upon Christ in our hearts. Thus, the absolution is the high point - it is the raw gospel moment. The supper then looks back to that moment and reinforces it. Does that help clarify where I’m coming from? [115] Posted by David Ould on 11-21-2008 at 06:49 PM · [top] David, I believe that the supper does look back but it also has a present and future dimension. For example, in the BCP Eucharistic Prayer “C” it is stated, “Let the grace of this Holy Communion make us one body, one spirit in Christ, that we may worthily serve the world in his name.” When I listen to your understanding of the Eucharist (what you prefer to call the Lord’s Supper) I think back to my Baptist roots at the carving on the church altar. “Do this in remembrance of me”. I think there, we saw communion only as a remembrance. This distinction in our perspectives may have some bearing on the issue at hand. Additionally, I do not believe as a deacon that I can (am able) to consecrate the bread and wine. [116] Posted by Fr. Dale on 11-21-2008 at 07:25 PM · [top] It’s ironic, this. I came to Anglicanism out of the Plymouth Brethren. The Brethren themselves separated from Anglicanism over some of the same theological convictions that are so prevalent in Sydney today. I remember reading some of the debates between John Nelson Darby and various CofE ministers and Church of Ireland over these same issues… no one (including Darby) suggested that lay-presidency was in any way compatible with the Anglican formularies. What Sydney is doing is not new and it is not Anglican. This is an old argument and one that had been answered fairly definitively back in the 19th century. [117] Posted by Fr. David McElrea (formerly farstrider+) on 11-21-2008 at 07:36 PM · [top] That should read “Cof E and Church of Ireland ministers.” [118] Posted by Fr. David McElrea (formerly farstrider+) on 11-21-2008 at 07:36 PM · [top] I believe that the supper does look back but it also has a present and future dimension. For example, in the BCP Eucharistic Prayer “C” it is stated, “Let the grace of this Holy Communion make us one body, one spirit in Christ, that we may worthily serve the world in his name.” Yes, perhaps I wasn’t clear enough. I meant to communicate that the Supper looks back in the service to the gospel set out and entered into in the confession and absolution. [119] Posted by David Ould on 11-21-2008 at 07:43 PM · [top] FarStrider, do you have a link to Darby on this matter? I can only find records of his eschatological material - which seems to garner far more interest across the internet! [120] Posted by David Ould on 11-21-2008 at 07:47 PM · [top] Farstrider, “What Sydney is doing is not new and it is not Anglican” As I begin to understand things better, I would agree with your summation. Maybe the differences have been there all along and not visible b/c the focus was on the revisionists. [121] Posted by Fr. Dale on 11-21-2008 at 07:53 PM · [top] David, Alas, no. My father had the “Collected Writings of John Nelson Darby”—all 34 volumes of them, but they have since been sold off. Within those volumes, however, there are a number of polemical pieces directed towards Anglican ecclesiology and Roman Catholicism. Much is on the nature of the Church itself, much is on the nature of the Lord’s Supper, which is interpreted in thoroughly Zwinglian terms. Following their convictions on the essentially mystical nature of the Body of Christ, and the emphasis on the autonomy of the local assembly, the forerunners of the Brethren (many of whom were Anglican ministers and/or members of the Aristocracy) gathered around the Lord’s Table together with Baptists, Methodists, Quakers and more. In short order, non-Anglican clergy and then laity began to administer the elements of bread and wine. This led to the threat of discipline and the inevitable departure from Anglicanism. As my own forbears left Anglicanism, it behooved me to understand the arguments involved and be able to give a reason for my “re-entry.” I imagine Moore Theological College might have the aforementioned series… it seems like someone oer there has been influenced by certain of the early Brethren writers anyway. [122] Posted by Fr. David McElrea (formerly farstrider+) on 11-21-2008 at 08:07 PM · [top] I might add, the biblical basis for “lay-presidency” (it wasn’t called this because the Brethren do not recognize any such thing as clergy/laity distinctions) was that of the priesthood of all believers. To acknowledge clergy was to acknowledge an underlying sacerdotalist mindset which was contrary to Scripture. I’m hearing echoes of this too, here and from some of my Sydney friends. Where will it stop, I wonder? [123] Posted by Fr. David McElrea (formerly farstrider+) on 11-21-2008 at 08:23 PM · [top] To acknowledge clergy was to acknowledge an underlying sacerdotalist mindset which was contrary to Scripture. Yes, and this was an over-reaction. Scripture makes it clear that there are deacons, elders and overseers (are the latter much the same in Scripture?) that have specific functions. Nevertheless, the same Scripture that sets out those functions does not include presidence at the Supper. And there lies the tension. [124] Posted by David Ould on 11-21-2008 at 08:27 PM · [top] Just a quick question - David do you recognise as Anglican the sacramental theologies that appear from the early seventeenth century onwards (eg Andrewes) amongst Church of England theologians? I understand you disagree with such thinking but am unclear if you think those theologies should be part of the the ongoing life of the Anglican family of churches. [125] Posted by driver8 on 11-21-2008 at 08:43 PM · [top] driver8 - no, I would consider them a move away from the theology of the 16th C Anglican Reformation. Again, this is the tension that Richardson has pointed to - that there are prevailing theologies in the Anglican Communion that are somewhat at odds with the Articles. [126] Posted by David Ould on 11-21-2008 at 08:49 PM · [top] David, They had deacons and elders (elder and overseer were considered the same office), but these positions were not distinguished as “clergy.” If you’re going for a purely New Testament pattern (acknowledging that this is speculation-bound to some extent) it would be hard to argue with the Brethren writings. If, however, you accept the idea that Tradition has anything to say to us at all (as per Hooker for example, this isn’t the way to go. [127] Posted by Fr. David McElrea (formerly farstrider+) on 11-21-2008 at 08:59 PM · [top] Thanks David - I am always thankful your clarity - even when I disagree deeply with your conclusions. Are there sixteenth century Anglican theologians who argue for diaconal or lay presidency at holy communion? Is it a view held by Cranmer himself? I recall that lay preaching was strongly disapproved in the reformation Church of England. [128] Posted by driver8 on 11-21-2008 at 09:04 PM · [top] Are there sixteenth century Anglican theologians who argue for diaconal or lay presidency at holy communion? Is it a view held by Cranmer himself? No, I don’t think the position was held out specifically. But there are reasons for that. Your next question helps explain: I recall that lay preaching was strongly disapproved in the reformation Church of England. Yes, although initially not because of any clericalism but because everyone was so poorly biblically literate. As I suggest above, this was the reason for the homilies - so that even those who were not trained might be able to share a useful word. Now, of course, the reverse is true (at least here in Sydney). We have a highly biblically literate clergy and laity and so the protections that Cranmer rightly put in place are no longer needed. I want to suggest that Cranmer would only approve of the broadening of this ministry now that the Bible was truly heard and understood. [129] Posted by David Ould on 11-21-2008 at 09:12 PM · [top] Writing, admittedly, as an outsider but a long-ago Anglican, I can’t help being very puzzled by Mr. Ould’s discussion. He says: It is no surprise that Sydney is a place that, while having a very low rate of usage of the Prayer Book, has a very high allegiance to the 39 Articles and the theology of the Prayer Book. He also discounts completely the universal practice of the Anglican Church, enshrined clearly in its ordinal, of maintaining the three Apostolic orders of ministry with their appropriate functions. Now, my question is: if you don’t use the BCP and don’t intend to follow the Anglican practice of the ministry, what makes you an Anglican Church, beyond, perhaps, the sign out front? If you deny the distinctives of Anglicanism, it would seem far more honest to join a free church where you would not be expected to use the BCP and where anyone who wanted to could preside at Communion. Rather than introducing more confusion and willful tampering with Anglican doctrine and practice, why not just go your own way and leave the Anglicans to continue to practice their faith as they always have? [130] Posted by Fr. S. J. on 11-21-2008 at 09:27 PM · [top] Thanks for a very fine article. I think a separate article would be very helpful; one that specifically addresses (1) the difference between this and the ordination of women to the diaconal, priestly and episcopal office and (2) the difference between this and the ordination of LGBT people to diaconal, priestly and episcopal office. Thank you in advance. [131] Posted by THATKindofChristian on 11-21-2008 at 09:44 PM · [top] The Homilies also initially served to control the preaching of clergy who were ordained before the various splits with Rome. Likewise the attempts to control seperatist anabaptist house churches speaks not only to a concern about biblical illiteracy but a focus on curbing what might be seen as subversive activity. As I understand it, the reformation Church of England argued that it was the clergy who exercised spiritual authority over Word and Table, as an expression of the Royal Supremacy. In other words theirs was an authority derived from the Sovereign’s rule over the church. So we see in the early reformation Church of England a kind of tactical clericalism. In principle churches might be rightly ordered in a variety of ways. In the Church of England the Magistrate (monarch) had decreed the fittingness of the three fold order of ministry. I guess one question, on this kind of reformed understanding, is who is the appropriate authority to make such a decision now? I note the possibility that it may come, in the end, to the secular courts in Australia. Perhaps ironically this may be a setting most fitting for a church that looks so strongly to the 1560s and 1570s for its theology. [132] Posted by driver8 on 11-21-2008 at 09:46 PM · [top] #129 David We have a highly biblically literate clergy and laity and so the protections that Cranmer rightly put in place are no longer needed. I want to suggest that Cranmer would only approve of the broadening of this ministry now that the Bible was truly heard and understood. It is hard for us to catch up with that great seat of learning, Sydney and the highly educated young people of Australia who have brought us the linguistic development of the Australian rising interrogative inflection and are now fully trained to minister without training for ordination and are fully cognisant of the Articles and Book of Common Prayer without apparently the need to read them? I am like in awe? [133] Posted by Pageantmaster ن on 11-21-2008 at 09:51 PM · [top] oh Elizabeth! You know very well the differences. Homosexual practice is quite clearly proscribed in Scripture whereas administration of the Supper is not even mentioned. Not, of course, that you stand much for the authority of Scripture. I do note that your last sermon published on your site managed to call both Matthew and Zephaniah “wretched”. There is a world of difference between your, frankly, disgraceful unwillingness to sit under Scripture and the discussions being had here. That you would even begin to equate the two indicates how little you understand or farily represent those you would criticise. But then you call yourself “evangelical” on your blog, so accurate use of words has never been a strong point. [134] Posted by David Ould on 11-21-2008 at 09:54 PM · [top] It is hard for us to catch up with that great seat of learning, Sydney and the highly educated young people of Australia who have brought us the linguistic development of the Australian rising interrogative inflection and are now fully trained to minister without training for ordination and are fully cognisant of the Articles and Book of Common Prayer without apparently the need to read them? I am like in awe? Wot you is not realisin’, is that the English church has been full of geezers ‘oo’s grammar is all over thah shop. it’s pukka. I think you are overstating my position. I did not claim (nor require) that all those that minister do not read to read the BCP. David “Diamond” Ould. [135] Posted by David Ould on 11-21-2008 at 09:59 PM · [top] David, in TEC Liberal Land, “evangelical vs catholic” seems to be mostly about how much incense people use. I’ve been told before by a TEC Liberal that Anglo-Catholic is merely a liturgical tradition, not a theology. The same person said, in reference to the Bible, “We got rid of the Pope a long time ago and now we are finally getting rid of the Paper Pope”. [136] Posted by AndrewA on 11-21-2008 at 10:01 PM · [top] Yes - if we accept the premise that we’re working within a particular kind of reformed theology - a theology that predominated within the Church of England between say 1560 and 1620 - then churches can be rightly ordered in a variety of ways that are consonant with Scripture. However, homosexuality is clearly prohibited within Scripture. The real debate to be had here is about: 1. The place of other theological starting points (premises) within the Anglican tradition. 2. Who has authority within Anglicanism to take such decisions about church order. That’s a good reformation question and I’d like to see David argue why an Archdiocese has such authority. [137] Posted by driver8 on 11-21-2008 at 10:08 PM · [top] #100 Authorized Version: John 15:16 Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you. Acts 1:21Wherefore of these men which have companied with us all the time that the Lord Jesus went in and out among us, 22Beginning from the baptism of John, unto that same day that he was taken up from us, must one be ordained to be a witness with us of his resurrection. 23And they appointed two, Joseph called Barsabas, who was surnamed Justus, and Matthias. 24And they prayed, and said, Thou, Lord, which knowest the hearts of all men, shew whether of these two thou hast chosen, 25That he may take part of this ministry and apostleship, from which Judas by transgression fell, that he might go to his own place. Now we can say what we want but the KJV is a literal translation and not a dynamic equivalent like the NIV. Perhaps the argument is framed here the way it is because one side is not reading a Bible but a facsimile. Acts 14:23 And when they had ordained them elders in every church, and had prayed with fasting, they commended them to the Lord, on whom they believed. 16:4 And as they went through the cities, they delivered them the decrees for to keep, that were ordained of the apostles and elders which were at Jerusalem. Here the Scripture interprets itself regarding the power to bind and loose: Romans 13:1 Let every soul be subject unto the higher powers. For there is no power but of God: the powers that be are ordained of God. 2Whosoever therefore resisteth the power, resisteth the ordinance of God: and they that resist shall receive to themselves damnation. 3For rulers are not a terror to good works, but to the evil. Wilt thou then not be afraid of the power? do that which is good, and thou shalt have praise of the same: 1 Tim 2:7 Whereunto I am ordained a preacher, and an apostle, (I speak the truth in Christ, and lie not;) a teacher of the Gentiles in faith and verity. Titus 1:5 For this cause left I thee in Crete, that thou shouldest set in order the things that are wanting, and ordain elders in every city, as I had appointed thee: Explaining the difference between the Order of Aaron and Melchisedec: Hebrews 5:1 For every high priest taken from among men is ordained for men in things pertaining to God, that he may offer both gifts and sacrifices for sins: 2Who can have compassion on the ignorant, and on them that are out of the way; for that he himself also is compassed with infirmity. 3And by reason hereof he ought, as for the people, so also for himself, to offer for sins…. 6As he saith also in another place, Thou art a priest for ever after the order of Melchisedec. [138] Posted by Just Wondering on 11-21-2008 at 10:10 PM · [top] thanks Driver8: I’d like to see David argue why an Archdiocese has such authority. As I argued above, I think Article 34 provides the authority. Of course, that also means that we are taking a different view as to what sort of (T/t)radition the question of administration is. [139] Posted by David Ould on 11-21-2008 at 10:10 PM · [top] I’ve been told before by a TEC Liberal that Anglo-Catholic is merely a liturgical tradition, not a theology. Which reflects more on the ignorance of the TEC liberal than it does of Anglo-Catholicism. [140] Posted by oscewicee on 11-21-2008 at 10:11 PM · [top] the difference between this and the ordination of women to the diaconal, priestly and episcopal office and Actually in my mind it is exactly the same. In both cases, a lay person is pretending to a function which is not theirs. Unfortuanate, but it recently occured to me that if those that are really particular about such things are willing to put up with WO, then there is little reason they shouldn’t be willing to put up with lay presidency, as long as no one is forcing it on them. (2) the difference between this and the ordination of LGBT people to diaconal, priestly and episcopal office. When did GLBT become LGBT? My concern on that matter is limited exclusivly to the behavoir and teachings of said individuals, not to any imagined categories that the activists have boxed them into based on their sexual desires. [141] Posted by AndrewA on 11-21-2008 at 10:17 PM · [top] David, are you arguing that the Archdiocese is a “particular” church under the terms of Article 34? If so, I think it’s a case to be made rather than asserted. It might help your case - at least in your own terms - if you could show that the Archdiocese of York was considered a “particular” church under the terms of this article. [142] Posted by driver8 on 11-21-2008 at 10:23 PM · [top] David, In your post on #115 you state, “it is interesting that the BCP consistently speaks of the Lord’s Supper, not “Communion”.” I think you are confusing the ‘Lord’s Supper’ in “A prayerbook for Australia” (1998) with “Holy Communion” in the BCP. Also in the Australian Prayerbook, the rubrics specifically state that 1. the priest pronounces the absolution and 2. offers the “authorized prayer of Thanksgiving and Consecration”. How can a diocese approve a deacon or lay person presiding if it would be against the rubrics of your prayerbook? [143] Posted by Fr. Dale on 11-21-2008 at 10:24 PM · [top] thanks just wondering, let me take your points in turn: John 15:16 uses eklegw -a simple word of choice or selection, Acts 1:22 simply states in greek that “one of these men must become a witness…” (ie there is no choice or ordination language), 14:23 has “xeirotonew” - “to choose by hand”, and 16:4 speaks of decisions “ordained” (better translated as “judged” (the greek being krinw). I’m not sure how you build this up to a sacerdotal doctrine of ordination. In fact I’m flummoxed as to how you get there. Similarly 1Tim 2 7 has a form of “tithemi” - to be placed. Titus 1 5 has similar “katisthemis” - to put in place. Again, there is no sacerdotal indication in any of these words. As for Romans 13, it speaks of how God has ordained (for want of a better word) the power of civic authorities. I’m not sure what you are arguing here - that the civic authorities have a similar status to clergy? Finally with respect to the Aaronic and Melchizedek priesthoods I am not clear what you are arguing. The book of Hebrews compares the two, pointing out that the Aaronis was insufficient and temporary and that Christ is of the greater and perfect order - Melchizedek. from there I am not sure what you are arguing. The term “priest” (hiereus) is only ever used in the NT of Jesus, the OT priests who foreshadowed His work, and all believers (so 1Pet 2:5&9;). It is interesting that nowhere does the NT refer to church leaders specifically as priests. [144] Posted by David Ould on 11-21-2008 at 10:26 PM · [top] Which reflects more on the ignorance of the TEC liberal than it does of Anglo-Catholicism. Yes it does, which is why one recent liberal commentor can call themselves “evangelical, anglo-catholic and orthodox” with a straight face. They’re either ignorant or willfully ignoring the facts. [145] Posted by David Ould on 11-21-2008 at 10:29 PM · [top] #143 Dcn D, I think I’ve already gone over the presentation of the argument in the OP. I’m not sure what I can add to it. [146] Posted by David Ould on 11-21-2008 at 10:30 PM · [top] Holy Communion. So many as intend to be partakers of the holy Communion shall signify their names to the Curate at least some time the day before. If a Minister be persuaded that any person who presents himself to be a partaker of the holy Communion ought not to be admitted thereunto by reason of malicious and open contention with his neighbours, or other grave and open sin without repentance, he shall give an account of the same to the Ordinary of the place, and therein obey his order and direction, but so as not to refuse the Sacrament to any person until in accordance with such order and direction he shall have called him and advertised him that in any wise he presume not to come to the Lord’s Table; Provided that in case of grave and immediate scandal to the Congregation the Minister shall not admit such person, but shall give an account of the same to the Ordinary within seven days after at the latest and therein obey the order and direction given to him by the Ordinary; Provided also that before issuing his order and direction in relation to any such person the Ordinary shall afford him an opportunity for interview. The Table at the Communion time having a fair white linen cloth upon it, shall stand in the body of the Church, or in the Chancel, where Morning and Evening Prayer are appointed to be said. And the Priest standing at the north side of the Table shall say the Lord’s Prayer, with the Collect following, the people kneeling. BCP1662 [147] Posted by tjmcmahon on 11-21-2008 at 10:34 PM · [top] If one of you with a print copy would be good enough to check it against my 147 above….I seem to have some of my electronic copies mixed up, if I accidentally posted from the 1549 or 1552 I do apologize. The compilers of the various BCPs did not foresee the modern computer age- too many files on my computer named “Morning Prayer.rtf” etc. [148] Posted by tjmcmahon on 11-21-2008 at 10:47 PM · [top] thanks tjm. you are right, I have overstated my case. Both sets of terms were used. [149] Posted by David Ould on 11-21-2008 at 10:47 PM · [top] If one of you with a print copy would be good enough to check it against my 147 above….I seem to have some of my electronic copies mixed up, if I accidentally posted from the 1549 or 1552 I do apologize. The compilers of the various BCPs did not foresee the modern computer age- too many files on my computer named “Morning Prayer.rtf” etc. No need, I have already checked both my 1662 AND 1552. You are correct on both counts. [150] Posted by David Ould on 11-21-2008 at 10:49 PM · [top] As I understand it David is not arguing that lay or diaconal presidency is to be found within the BCP, Ordinal, or heretofore within any Anglican church. What he is arguing is that the Anglican reformers accepted a diversity of church orderings as being consonant with Scripture. In addition he is arguing that Sydney is rightly to be understood as a separate church body and so has the right to order the church in a way consonant with Scripture even if it is novel in Anglicanism. The questions remain: 1. Anglican theology didn’t stop in 1620. Many Anglicans have argued (against the Anglican reformers) that the three fold ministry is not an adiaphoron. In other words they accept as a premise a differing view of Tradition - or if you want the work of the Holy Trinity in time - than the Anglican reformers did. Is there place for their theology within Anglicanism? How will Sydney take into account the evident fact that some folks who see themselves as orthodox and wholly within Anglicanism argue what Sydney proposes to do is a communion breaking matter. 2. Even on their own reformed understanding - is the Archdiocese of Sydney a “particular” church? (It’s certainly not a “national” church). If they are not, even according to the Articles, they have no authority to change church order. [151] Posted by driver8 on 11-21-2008 at 10:52 PM · [top] The point is ‘justification by silence alone’ is not enough to overturn centuries of the churches practice guided by the Holy Ghost. What I am saying is that the translators (70 of them to render the AV with no dissent on the selection of the word ‘ordain’) of the Anglican Bible choose to use ‘ordain’ as the best way to describe what was implied by the whole of Scripture. Fact: the English Church saw fit to retained the ordained priesthood because the English Reformation restored catholicity. Call it what you will but no where is any presidency by those outside this order, this agency, implied or specified or ever mentioned prior to the reformation. Whether to be set aside, ordained how ever you want to frame it it is still what it is. Polycarp was ‘ordained’ by St John. Irenaeus referred to “the succession from the apostles” Chrystostom wrote a great work on the subject. Cyprian talks about the priesthood regularly “the office of our priesthood”; “the vigor of the priesthood”; “hands were placed upon the repentant by the bishops and clergy”; “the Church is founded upon the bishops, and every act of the Church is controlled by these same rulers”; Ignatius- “It is not right either to baptize or to celebrate the agape apart from the bishop; but whatever he approves is also pleasing to God—so that everything you do may be secure and valid. Another Biblical example of ordained men ordaining others: Acts 6:5-6: “And the saying pleased the whole multitude: and they chose Stephen, a man full of faith and of the Holy Ghost, and Philip, and Prochorus, and Nicanor, and Timon, and Parmenas, and Nicolas a proselyte of Antioch: Whom they set before the apostles: and when they had prayed, they laid their hands on them.” Your problem is you have the weight of centuries to overturn and all the holy people that continued in the faith so you could challenge them and that you know more than the translators of the KJV, the Anglican Divines, the early church, what was and is seen buy the vast majority of Christians living and asleep as God’s design. Even second guessing the men who were ordained by Apostles or ordained by men ordained by Apostles . You have questioned much but have proved nothing to support LP other than you have your heart set on your own personal interpretation (2 Pet 1:20) I guess my big dig is that none of this is consistent with the Church as a whole and while different have errors when you superimpose them the errors become easily identifiable: in the same manner seeing what has been believed by the majority of those through out the history of the Church performs the same function. Lay presidency simply does not meet the test of history or necessity. The onus is not on me, I have claimed no man made innovation but you must make a case from Scripture for your lay presidency. I have offered many passages you have not offered a single one proving that the average man of faith went out and celebrated a Eucharist on his own- zero- zip. I am no expert but what I have read about the people of that time and their reaction to the gospel and the Apostles and those they ordained it is counter intuitive much less unscriptural to think they would assume responsibility for the Body and Blood of our Lord so cavalierly. [152] Posted by Just Wondering on 11-21-2008 at 11:34 PM · [top] Sorry I am not getting something right I mean to address Mr. Ould [153] Posted by Just Wondering on 11-21-2008 at 11:37 PM · [top] Just Wondering: What I am saying is that the translators (70 of them to render the AV with no dissent on the selection of the word ‘ordain’) of the Anglican Bible choose to use ‘ordain’ as the best way to describe what was implied by the whole of Scripture. You misunderstand me, I am quite happy for each of those words to be translated as “ordain”, given that it has a wider semantic range. What I am asking you to demonstrate is that any of those original words have the sacerdotal understanding of “ordain” that you keep insisting upon. [154] Posted by David Ould on 11-21-2008 at 11:38 PM · [top] I wonder if my connection is a problem I included a quote with the verses you answered but it did not show??? ShouId read: ” guess my big dig is that none of this is consistent with the Church as a whole and while different bible translations have errors when you superimpose them the errors become easily identifiable” [155] Posted by Just Wondering on 11-21-2008 at 11:41 PM · [top] David, “Communion” is not somehow placing us closer to Christ than a simple response to the gospel can. And there, I think, is the crux of the matter, at least in terms of why so many look upon Sydney’s decision and resulting actions as non-catholic. You may as well have said baptism is not somehow placing us closer to Christ than a simple response to the gospel. Whether Sydney views baptism in this light is not the point. I am simply trying to help you understand how the majority of us receive this statement. Indeed, it is interesting that the BCP consistently speaks of the Lord’s Supper, not “Communion”. Here you are emphatically and demonstrably incorrect. From Sydney’s own web site, Form 1 of the service uses the word supper 1 time (in the service title only), and Communion 4 times. In Form 2 (A and B), supper is found 4 times (of which 2 times are in the A and B titles), and Communion is found 5 times. In reference to the 1662 BCP, which is the standard to which GAFCON has ascribed, the word supper, counting both upper- and lower-case S, appears exactly 6 times in the service text; once in the title and these 5: * “...I intend, by God’s grace, to celebrate the Lord’s Supper” * “...withdrawing yourselves from this holy Supper…” * “...Likewise after supper he (d) took the Cup…” * “...shall be no celebration of the Lord’s Supper…” * “...it is ordained in this Office for the Administration of the Lord’s Supper…” The word Communion, with capital C, is mentioned in the service title and 27 other times: * “So many as intend to be partakers of the holy Communion…” * “...any person who presents himself to be a partaker of the holy Communion…” * “The Table at the Communion time…” * “...shall notice be given of the Communion…” * “And when there is a Communion…” * “...the celebration of the holy Communion…” * “...otherwise the receiving of the holy Communion…” * “...that no man should come to the holy Communion, but with a full trust in God’s mercy…” * “...in case he shall see the people negligent to come to the holy Communion…” * “...that ye will be partakers of this holy Communion.” * “...so it is your duty to receive the Communion…” * “At the time of the Celebration of the Communion…” * “...ye that mind to come to the holy Communion…” * “Then shall the Priest say to them that come to receive the holy Communion…” * “...in the name of all those that are minded to receive the holy Communion…” * “...in the name of all them that shall receive the Communion…” * “Then shall the Minister first receive the Communion…” * “...who are partakers of this holy Communion…” * “...when there is no Communion…” * “...the Collects either of Morning or Evening Prayer, Communion, or Litany…” * “...(if there be no Communion)...” * “...all that is appointed at the Communion…” * “...to receive the Communion…” * “...yet there shall be no Communion…” * “...they shall all receive the Communion…” * “The Bread and Wine for the Communion shall be provided by the Curate and the Church-wardens…” * “...for the avoiding of such profanation and disorder in the holy Communion…” This of course does not refute Sydney’s debating position, but it is incorrect of you to make such a claim as the neither the 1662 nor Sydney’s own text consistently speaks of the Lord’s Supper, not “Communion”. The fact is, exactly the opposite is true. [156] Posted by Antique on 11-21-2008 at 11:44 PM · [top] I do not remember using the word “sacerdotal”. But since you bring it up and in light of the volume of verses I have offered including those of Hebrews I would ask you to use the Scripture alone and disprove it. Can you do that? After all it is your standard and I have the Fathers on my side. [157] Posted by Just Wondering on 11-21-2008 at 11:46 PM · [top] This of course does not refute Sydney’s debating position, but it is incorrect of you to make such a claim as the neither the 1662 nor Sydney’s own text consistently speaks of the Lord’s Supper, not “Communion”. The fact is, exactly the opposite is true. Yes, I had already explicitly noted that in comments 149&150;above. As for your points on the understanding of the sacraments, I wholly agree. [158] Posted by David Ould on 11-21-2008 at 11:48 PM · [top] I do not remember using the word “sacerdotal”. But since you bring it up and in light of the volume of verses I have offered including those of Hebrews I would ask you to use the Scripture alone and disprove it. I have already noted that the NT Scriptures never use the “hierius” word group to describe “ordained” ministers. Rather the letter to the Hebrews itself states that Jesus is the inheritor of that priesthood. Even in Hebrews leaders are mentioned (ie 13:17), but not as “priests”. Can you, in turn, show anywhere in the NT Scriptures where church leaders are described as “priests”? Since there is not such place I am not clear as to why there is this insistence upon it. After all, as Anglicans (or at least as an Anglican Clergyman) we hold that: VI. Of the Sufficiency of the Holy Scriptures for Salvation. Holy Scripture containeth all things necessary to salvation: so that whatsoever is not read therein, nor may be proved thereby, is not to be required of any man, that it should be believed as an article of the Faith, or be thought requisite or necessary to salvation. What cannot be read in Scripture cannot be required. That includes the naming and understanding of NT church leaders as “priest”. Cyprian and others may have thought otherwise, but that does not change what Scripture says. And yes, that is me saying that, in this instance, they are wrong to insist upon that which Scripture does not insist upon. Let God be true and every man a liar. [159] Posted by David Ould on 11-21-2008 at 11:55 PM · [top] Does every man include you? I still read nothing about lay presidency in Scripture and you demand proof from scripture but only quote the Articles from your modern perspective. [160] Posted by Just Wondering on 11-21-2008 at 11:59 PM · [top] [152] Just Wondering wrote: What I am saying is that the translators (70 of them to render the AV with no dissent on the selection of the word ‘ordain’) of the Anglican Bible choose to use ‘ordain’ as the best way to describe what was implied by the whole of Scripture. It should be remembered that the AV was not translated in a vacuum. The translators were given guidelines to constrain their efforts. One of which was: The old ecclesiastical words shall be kept, viz. The word ‘church’ not to be translated ‘congregation.’ In other words, the translation was a priori not allowed to threaten the established ecclesiastical order. The modern translations (NASB, ESV) are therefore much better gauges of proper word choice in this regard. carl [161] Posted by carl on 11-21-2008 at 11:59 PM · [top] Some new translations do the same thing and do not render Bishop but some other word knowing that Episcopoi undermines Calvin’s invention. [162] Posted by Just Wondering on 11-22-2008 at 12:01 AM · [top] “Cyprian and others may have thought otherwise, but that does not change what Scripture says. “ I live in the south and on a farm that saw action during the Civil War. I know how many yankees trespassed here and when and what armies and commanders were nearby and that was 145 years ago. You would have us believe that a man ordained by St John or the man ordained by him did not understand or remember what St John either said to them or what he practiced himself in less than a generation and that they were to feeble to be clear to their students. That people willing to die for their faith would either change the faith for some unknown reason or distort it. Where is your proof? That is a lot to swallow Mr. Ould. I think that the secrecy required to maintain the faith ought not be used as a vehicle to impose one’s prejudices on it. My read is the literal read. When Jesus says I am the way and the life I believe him. When he says I am the bread of life I believe it. What is more is I understand it somehow when I receive. That alone speaks more than all the Continentals combined. [163] Posted by Just Wondering on 11-22-2008 at 12:11 AM · [top] [162] Just Wondering Some new translations do the same thing and do not render Bishop but some other word knowing that Episcopoi undermines Calvin’s invention. There is no concept of “Bishop” in Scripture. There is simply no way to exegetically separate ‘presbyteros’ and ‘episkopos’ into separate categories. They are interchangeable terms as far as Paul is concerned. The office of Bishop is a tradition. You may argue that it is a good and useful tradition, but it is a tradition none the less. carl [164] Posted by carl on 11-22-2008 at 12:16 AM · [top] It does seem to me that Sydney’s proposal brings into question the extent to which the 1662 BCP and Ordinal can function as a standard of church order around which Anglicans can unite. [165] Posted by driver8 on 11-22-2008 at 12:17 AM · [top] “Cyprian and others may have thought otherwise, but that does not change what Scripture says. “ BTW you still have not met your own standard and proved your positions by “what Scripture says” So Mr. Ould what does Scripture say about your positions? [166] Posted by Just Wondering on 11-22-2008 at 12:20 AM · [top] I would argue episkopos is bishop as bishop is episkopos. Bishop as a word is a derivative… language changes but the underlying understanding is the same. The reason it is left out is not because another word is more accurate it is because that word reflects that which the Contintental Reformers lost and cannot bring themselves to admit it. Except of course the Methodists who did admit it if for a moment: “Wesley in his “Korah” sermon, scathingly censured those who would depart from the Apostolic Order, and Dr. Coke, one of the first Superintendents, as they were then called, of the Methodists in this country, made proposals to Bishops White and Seabury, that he and Mr. Ashbury (the resident Methodist Superintendent) should be consecrated Bishops, and proposed a reunion of Methodists and Churchman on a basis conceding a reordination of their ministers.” [167] Posted by Just Wondering on 11-22-2008 at 12:25 AM · [top] #164 I think put crudely that the Anglican reformers view is that episcopacy is consonant with Scripture and thus the Magistrate (monarch) is quite within his or her rights to determine it as a fitting mode of ordering the church within England. Outside England other forms of church ordering (eg presbyterian) might be equally consonant with Scripture and legitimately authorised by the relevant authority. Of course, relatively quickly (within two or three generations) Anglicans began to argue that episcopacy was divinely mandated. (Such was broadly the view taken at the Restoration in 1660. Thus the demand that presbyterian ministers be episcopally reordained) [168] Posted by driver8 on 11-22-2008 at 12:26 AM · [top] Carl, I have no problem with right Tradition it is the work of the Holy Ghost. Unless of course you can prove by Scripture that the Holy Ghost did not come to the early Church and guide it. [169] Posted by Just Wondering on 11-22-2008 at 12:30 AM · [top] only quote the Articles from your modern perspective Yes, this is your claim - but you have not demonstrated it. What do you think Article VI means when it states: VI. Of the Sufficiency of the Holy Scriptures for Salvation. Holy Scripture containeth all things necessary to salvation: so that whatsoever is not read therein, nor may be proved thereby, is not to be required of any man, that it should be believed as an article of the Faith, or be thought requisite or necessary to salvation. ? I think it means that nothing should be required to be believed by us, except that which can be read in or proved by Scripture. What do you think it means? [170] Posted by David Ould on 11-22-2008 at 12:58 AM · [top] [169] Just Wondering I have no problem with right Tradition it is the work of the Holy Ghost. Unless of course you can prove by Scripture that the Holy Ghost did not come to the early Church and guide it. The burden of proof is upon you to show why your tradition is binding upon another if that tradition is not fundamentally rooted in Scripture. Tradition is not ontologically equal with Scripture. It is not theopneustos. It is not and never has been a separate form of revelation to man. How then is it binding? If the concept of ‘bishop’ cannot be exegetically derived from Scripture (and it cannot) that how is the conscience bound by that tradition? You say the Holy Spirit guided the church. But the means by which the Holy Spirit guides the church is Scripture. That means traditions cannot stand Scripture on its head - like for example carving ‘presbyteros’ and ‘episkopos’ into separate categories where no such separation exists. Does a man sin if he rejects the monarchial episcopate? Here I think is the real crux of this argument on Lay Presidency. There has been very little response to the central question in David Ould’s argument: “What does a presbyter contribute to Holy Communion that is essential?” There has instead been much fulmination about the impact of Lay Presidency on Anglican ecclesiology. But if that order is rooted only in tradition, why can you not let Sydney do what it likes? Why do you insist on binding its conscience? And that is what has happened on this thread. Count how many times it has been stated that “It just isn’t Anglican. Go be a Presbyterian or Baptist or (gasp!) a Darbyite if you like, but leave the Anglican Chruch alone!” That isn’t much of an argument, and it is even less an argument if the tradition in question cannot be successfully rooted in Scripture. carl [171] Posted by carl on 11-22-2008 at 12:59 AM · [top] I’ll just throw this out for general consumption of information. I know it won’t make a difference, but it is an interesting set of correlated statements. According the Prayer Book Society of Australia: “THE BOOK OF COMMON PRAYER (1662) which includes THE ORDINAL for the making, ordaining and consecrating the bishops, priests and deacons in the Anglican Church, together with THE THIRTY-NINE ARTICLES OF RELIGION, is declared by the Constitution of the Anglican Church of Australia to be ‘the authorised standard of worship and doctrine in this Church, and none of its principles may be contravened’ and, according to the 1662 BCP, The Form and Manner of Making of Deacons: IT appertaineth to the Office of a Deacon, in the Church where he shall be appointed to serve, to assist the Priest in Divine Service, and specially when he ministereth the holy Communion, and to help him in the distribution thereof; and to read Holy Scriptures and Homilies in the Church; and to instruct the youth in the Catechism; in the absence of the Priest to baptize infants; and to preach, if he be admitted thereto by the Bishop. And furthermore, it is his Office, where provision is so made, to search for the sick, poor, and impotent people of the Parish, to intimate their estates, names, and places where they dwell, unto the Curate, that by his exhortation they may be relieved with the alms of the Parishioners, or others. Will you do this gladly and willingly? [172] Posted by Antique on 11-22-2008 at 01:31 AM · [top] #170 David, I think “proved” is the key word there. I don’t know the history of interpretation of the article but have a couple of thoughts: 1. Does “proved” here carry its now almost archaic meaning of “tested”? In other words doctrine must be tested against Scripture. As in the often misquoted proverb, “the proof of the pudding is in the eating” which of course means that one tests the quality of a pudding by eating it. 2. Or perhaps some standard of logical or legal reasoning (proof) is indeed intended. Deductive necessity? Inductive? Abductive inference to the best explanation? Beyond reasonable doubt (according to whom)? In other words, I agree that the Article is very significant but that it is capable of being genuinely affirmed as truthful by people with a wide variety of theologies and ecclesiologies. [173] Posted by driver8 on 11-22-2008 at 02:38 AM · [top] #171 You need to specify what you mean by “exegetically derived”. What patterns of reasoning are appropriate as the church seeks to understand Scripture? For some of us tradition, in the sense I think you are using it, is nothing other than the church’s authoritative interpretation of Scripture. Jesus promised that the Spirit would lead the church into all truth. So: 1. Coming to an understanding of who is the church of which Jesus is speaking, is highly significant. (That looks to me to be, at least partially, an extra-Scriptural question). 2. How does one determine proper doctrinal development/clarification? That isn’t entirely separate from the first question but entails considering in addition what kinds of reasoning are appropriate to the church’s articulation of the deposit of faith. [174] Posted by driver8 on 11-22-2008 at 02:51 AM · [top] #171 Apologies - my first sentence sounds rude and was certainly not intended to - you don’t “need” to do anything! If you wanted to lay out the kinds of reasoning that allow one to say something is “exegetically derived” I would find it helpful. [175] Posted by driver8 on 11-22-2008 at 02:56 AM · [top] Rev. Ould, I must respectfully disagree regarding your statements that the Prayer Book counts Holy Communion as an inferior source of grace to Absolution. Ridley states that “we understand his [Christ’s] benefits to be greatest in the sacrament.”—that is, in comparison to the other means of grace (Absolution, etc). Blessings in Christ, William Scott Gal 3:26 For ye are all the children of God by faith in Christ Jesus. 27 For as many of you as have been baptized into Christ have put on Christ. [176] Posted by William on 11-22-2008 at 05:30 AM · [top] thanks William, that’s helpful. Where does Ridley say that? [177] Posted by David Ould on 11-22-2008 at 06:05 AM · [top] Rev Ould, Per this discussion, this is where I see you and I in disagreement. 1. We do not agree on the relative merit of Absolution and Communion. 2. We do not agree on what constitutes reformed Catholicism. 3. We do not agree on the relative contribution made by Tradition. 4. We do not agree on how damaging Lay Presidency is to the rest of the Anglican Communion. I appreciate the conversation but as I said on an earlier post, this conversation should have taken place before the fact not after the fact. I hope the practice will be revisited and reconsidered. I would be interested to know if this thread has had any effect on your position. [178] Posted by Fr. Dale on 11-22-2008 at 08:55 AM · [top] “The burden of proof is upon you to show why your tradition is binding upon another if that tradition is not fundamentally rooted in Scripture. Tradition is not ontologically equal with Scripture. It is not theopneustos. It is not and never has been a separate form of revelation to man. How then is it binding? You can’t have it both ways! You want to create a tradition out of thin air and deny that which was bound from the earliest time! There simply is no record that supports the existence of an alternative tradition that supports your argument and or speaks with the same definitiveness you demand of the one recognized bythe Fathers! No, the burden of proof is with the innovators. And as I have said, you have no equal tradition to site, only a man made idea based on a desire to interpret what you characterize as silence and then dismiss those who came before who had the power to bind and loose. You ask for proof from Scripture for tradition but Scripture is undeniably a product of inspired tradition. The same men operating under the guidance of the Holy Ghost who were ordained by Sts John and Paul and having the power to bind and loose are the same who mention the priesthood and passed down the Scriptures resulting in Athanasius’s pronouncement in his 39th festal letter to Alexandria. I remind you the power to bind and loose and to forgive sin’s or retain them was given in 33’ not 365’ or at the later councils that solidified the Canon or at the Reformation it was given By Christ not Calvin. Mr. Ould admits the Fathers say what they say but he and those supporting his position have not offered any reason why the Fathers did not receive the power to bind or loose prior to the Canon. Carl your argument on tradition requires a vacuum. It was remarked that Princes, according to a Council can overturn the Order and that the AV is a product of James intent to ‘colour’ the translation. James is a King preserving what was known to be God ordained. If a Prince can opverride the Apostolic Order surely a King can continue it. Mechelzidek was a King and a Priest. I leave you with this advice From Hebrews 13” 7Remember your leaders, who spoke the word of God to you. Consider the outcome of their way of life and imitate their faith. 8Jesus Christ is the same yesterday and today and forever. 9Do not be carried away by all kinds of strange teachings. It is good for our hearts to be strengthened by grace, not by ceremonial foods, which are of no value to those who eat them. 10We have an altar from which those who minister at the tabernacle have no right to eat. We have an “altar” that the Aaronic Order may not eat from we have a Great High Priest in the Order of Mechelzidek, The Apostles received power and the Spirt the laid hands on those they raised up to start and govern churches Not Aaronic but Mechelzidek. [179] Posted by Just Wondering on 11-22-2008 at 09:29 AM · [top] David, Article 6 is referring to the fact that nothing can be construed as necessary for salvation that is contrary to scripture. The ordering of the church is decidedly not bound by this stricture. The church has the authority to ordain rites and ceremonies according to tradition and any who break with it by their private opinion are to be disciplined (I do not have my BCP handy, but it is Article 34, I believe). Which is precisely what needs to happen to Sydney in this instance. This again, is my problem with Sydney’s actions. I agree that the three-fold order cannot be proven by scripture, and that the Articles hold out the possibility of a change in the structure and function of church government. But, in a global communion (which did not exist at the time) Sydney’s actions are akin to a bishop of the Church of England in the 1600’s trying to establish a puritan vision of the church in his diocese…it was not tolerated then, and should not be tolerated now because it overturns catholic order. Again, as mentioned before (107 above), how do you justify your sectarianism??? Arguing from scripture is simply not enough. Every evangelical sect does this…but unless you want to become another sect, you cannot argue this way. We are reformed and catholic. You can become a ‘bible’ church if you want. Been there, done that, had enough of the individualistic heresy here in America. You are making a big step away from the catholic order of the church and it is a big mistake. Also, I find it highly amusing that this argument is rooted in a concern to define the priesthood as relegated to those who would be rectors. You strengthen the priesthood in one direction by confinung its authority to ‘eldership’ while failing to recognize that the scripture speaks of elders (plural) in the local church repeatedly. Strikes me as patently unbiblical. No one is telling Sydney they have to believe in a sacerdotal priesthood…but neither is it ok for Sydney to tell everyone else that such an understanding cannot be retained (i.e., that it is worth breaking the catholic order over). Nothing in scripture requires it, but nothing in scripture forbids it either. [180] Posted by Rob Paris on 11-22-2008 at 10:51 AM · [top] It is from Ridley’s 1555 Disputation (which is a very detailed and informative read on this issue—of course, the same may be said of his other writings on the Sacrament). Blessings in Christ, William Scott Gal 3:26 For ye are all the children of God by faith in Christ Jesus. 27 For as many of you as have been baptized into Christ have put on Christ. [181] Posted by William on 11-22-2008 at 11:56 AM · [top] Sorry all—my last post is a response to Rev. Ould’s post #177 [182] Posted by William on 11-22-2008 at 11:58 AM · [top] The Ordinal states that the Historic Episcopate is the teaching of Scripture. IT is evident unto all men diligently reading holy Scripture and ancient Authors, that from the Apostles’ time there have been these Orders of Ministers in Christ’s Church; Bishops, Priests, and Deacons. Which Offices were evermore had in such reverend Estimation, that no man might presume to execute any of them, except he were first called, tried, examined, and known to have such qualities as are requisite for the same; and also by publick Prayer, with Imposition of Hands, were approved and admitted thereunto by lawful Authority. And therefore, to the intent that these Orders may be continued, and reverently used and esteemed in the Church of England, no man shall be accounted or taken to be a lawful Bishop, Priest, or Deacon, in the Church of England, or suffered to execute any of the said Functions, except he be called, tried, examined, and admitted thereunto, according to the Form hereafter following, or hath had Episcopal Consecration, or Ordination. Blessings in Christ, William Scott Gal 3:26 For ye are all the children of God by faith in Christ Jesus. 27 For as many of you as have been baptized into Christ have put on Christ. [183] Posted by William on 11-22-2008 at 12:10 PM · [top] p.s. Don’t know if I’ll be able to really resond to any further posts for the next while [184] Posted by William on 11-22-2008 at 12:11 PM · [top] Sorry, I expressed myself poorly in 180. Of course, nothing is to be believed that is contrary to scripture at any time. What I meant to say is that nothing is to be required for salvation that is not explicitly taught in scripture. The order of the church cannot contradict scripture, but it does not have to be explicitly taught therein according to the Artiles. For Sydney’s actions to be right, they either need to wait for the rest of the Communion to agree to such order as they desire to set out or prove that the current system actually goes against scripture, which is certainly not the case. [185] Posted by Rob Paris on 11-22-2008 at 01:43 PM · [top] #185 Do you think homoousios is taught explicitly in Scripture? [186] Posted by driver8 on 11-22-2008 at 01:51 PM · [top] Driver8, In the sense that the Articles meant it, yes I believe it is…I was using short-hand for the teaching in Article 6, which states, ...whatsoever is not read therein (Holy Scripture), nor may be proved thereby, is not to be required of any man, that it should be believed as an article of the Faith, or be thought requisite or necessary to salvation. I believe homoousios is proved by scripture in that it is requisite to make sense of what scripture teaches. I recognize that ‘explicit’ was not the best word to use in this instance since for many it connotes the idea that an idea must be proven by chapter and verse. But if an idea cannot be avoided in making sense of what scripture teaches repeatedly and consistently, it may also be called explicit. In such a situation, it is not merely implied, but ‘read out’ from scripture’s testimony as a whole. It is in this sense that I would say that homoousis is explicitly taught by scripture (and it is in this sense that I believe the Reformers also would have defended it as an Article of Faith necesssary to salvation). My real point, however, was to call attention to the fact that the evangelical insistence on scriptural warrant is not enough in matters of church order. There is no claim coming from me or any other Anglican evangelical that lay presidency hinders salvation. I believe my Baptist brothers and sisters, to whom I once belonged, are truly saved (though even many of them would not go so far as endorse lay presidency). The issue is church order, where respect for the rest of the catholic community should hold our conscience captive. Only practices which are clearly repugnant to the Word of God are to be rejected. Priestly presidency over the Eucharist may not be explicitly warranted by scripture, but it certainly is not contrary to it, either. All Sydney can do is present a case from silence, which they declare gives them license. I am simply arguing that they are acting like a ‘Bible’ church, not an Anglican church. We are a people who adhere to catholic order. So, again, I cry out, cease and desist. [187] Posted by Rob Paris on 11-22-2008 at 05:07 PM · [top] And therein lies the rub. Homoousios is not explicitly contained within Scripture. One might argue that it can be deduced from what is explicitly contained within Scripture both about Jesus and about the being of God. But if you permit such reasoning - and I take all orthodox are bound to do so - many other third, fourth and fifth century theological clarifications/developments (pick your favourite terminology) that are not explicit (remember homoousios is not once mentioned in Scripture) might at least claim, using just the same kind of reasoning, to be “proved” from Scripture. So for me a high ecclesiology begins with Jesus founding the church as the New Temple with its unbloody sacrifice (the eucharist) - with a distinctive and particular role given to apostles (Rock, Pillar etc..), christians as living stones, Christ as Cornerstone. [188] Posted by driver8 on 11-22-2008 at 05:57 PM · [top] Driver8, I think the issue lies in what ‘proven’ means. As one who leans more to the evangelical than the Anglo-Catholic side (though, I hope it is obvious that I have strong catholic concern as well), I am not ready to give the Church the ability to define what is necessary to salvation beyond scripture. But, the Church does have the authority to declare what scripture proves in controversial matters (Article 20). And this is precisely what the councils were doing. They were not creating new doctrine, but clarifying what is taught in scripture. So, I appreciate the position you seem to be laying out, but for a variety of reasons, cannot go there. Scripture remains the source of all doctrine, including homoousios. The Church merely ratifies what it finds explicitly (in the sense laid out in 187 above) taught there. But, matters of church order are not held to so strict a level of interpretation of scripture. On matters of order the church can speak without the explicit teachings of scripture to back them. In matters of church order, it is enough that nothing is ordained contrary, to scripture. Sydney will not allow itself to be bound by something it does not find explicitly taught in scripture. I am trying to point out that it does not need to be explicitly taught for it is not a matter of salvation. You can disagree with me that homoousios is ‘explicitly’ taught in scripture, but I feel that if it is not, it was not right for the council to ratify it as necessary to salvation. I believe homoousios is explicitly taught, not because the word is used, but because the New Testament makes no sense of God without it. Are there other similar doctrines (such as Christ’s two natures)? Yes. Does this in any way hinder my belief in scripture as the norm for doctrine rather than tradition? Not in the least. Thanks for the interesting discussion. [189] Posted by Rob Paris on 11-22-2008 at 06:49 PM · [top] My point is if we can count homoousios as appropriately derived from Scripture (ie if that kind of reasoning is what counts as “proof” in this circumstance) then we should, in principle, be able to look at other doctrines of the third, fourth and fifth century and see if they are “proved” from Scripture in a similar manner. In other words - you define homoousios as Scripture rather than Tradition even though it is never mentioned in Scripture - because it is capable of being deduced from what is contained in Scripture. If you reason in this way - and I think all orthodox are obliged to do so - it’s worth thinking what other doctrines are similarly contained “within” Scripture even though not explicitly mentioned. [190] Posted by driver8 on 11-22-2008 at 07:07 PM · [top] Driver8, No argument from me…I completely agree with the way you stated it. [191] Posted by Rob Paris on 11-22-2008 at 08:27 PM · [top] In other words - you define homoousios as Scripture rather than Tradition even though it is never mentioned in Scripture - because it is capable of being deduced from what is contained in Scripture. If you reason in this way - and I think all orthodox are obliged to do so - it’s worth thinking what other doctrines are similarly contained “within” Scripture even though not explicitly mentioned. Yes, some things are clearly stated, even if the early church used other means of expression. So, for example, the term homoousious was necessary to distinguish from Arius’s “homoioisious”. Nevertheless, the concept is almost explicit. For example, “the Word WAS God”. It just doesn’t get clearer than that. [192] Posted by David Ould on 11-22-2008 at 09:44 PM · [top] On the contrary - homoousios only makes sense in the context of a series of other, if you want, deductions from Scripture (e.g. divine simplicity). In other words, what it means to “be” God (or, if you want, what language we must use to talk about the being of God) needed itself to be “deduced” from Scripture. Or, to put it exegetically, the move from John 1 to homoousios entails a view of the being of God that itself was not directly stated but “deduced” from the text of Scripture. [193] Posted by driver8 on 11-22-2008 at 11:54 PM · [top] The Baptist church of my youth has the pastor cite the words of institution and the deacons distribute. Doing something other than that, while I doubt it is in writing anywhere, would be unthinkable. I find it quite odd that Anglicans would have so much difficulty with something that Baptists simply accept. Siangombe Bapto-Catholic [194] Posted by Siangombe on 11-23-2008 at 08:27 AM · [top] Siangombe, There is nothing odd about it at all. If you knew as much about Anglicans and Catholics as you think you do, you would uinderstand that. The odd thing is what Baptists do—your clergy are not ordained at all in the sense that Anglicans all over the world use the term ordination. That is also the case with your deacons. The problem is that Anglicans in Sydney are not fully Anglican in the sense that the word “anglican” is used all over the world. The correct name for their religion is “Anti-Catholicism”—as your’s is also. This is not what Christianity is all about, according to the beliefs of most of the world’s remaining Anglicans. And that is why they want lay people to say Mass—anything that will be the opposite of “catholic” is what they want. Does that help you to make better sense of it? [195] Posted by GB on 11-23-2008 at 09:21 AM · [top] [195]: The odd thing is what Baptists do—your clergy are not ordained at all in the sense that Anglicans all over the world use the term ordination. It’s been a long thread, which I confess I had not thoroughly read myself before posting. I suggest you do a search of the thread on the word “Baptist”. You will note considerable variation on what the word means. That’s because “Baptist” is much more generic than “Anglican”; there are many different flavors and practices. For example, I have a friend who was ordained a deacon in a Baptist church (he now attends an Anglican church). Yet I never saw a deacon ordained growing up. The correct name for their religion is “Anti-Catholicism”—as your’s is also. That’s a misinterpretation of my post, confusing my history (inferred from my signature) with my standing. I am Anglican. As a matter of fact, you would find me falling right into the First Things mainstream of those seeking rapprochement of orthodox Christians everywhere, from flaming Pentecostal to Coptic Egyptian. My point was that if even Baptists consider the Lord’s Supper something to be “done” by an ordained person who is not a deacon, but someone resembling a presbyter, how much more should that be the case in an Anglican setting? Also note that my signature line was lighthearted. “Bapto-Catholics” are a very odd breed, indeed, if they exist, as are Anglo-Baptists, but maybe Pente-Baptists not so much. Apologies if my levity mislead. And a more general question: I see that some referred to Baptists as Donatists. As far as this is not a category error (not sure that Donatism applies to an expression of Christianity that only weakly uses sacramental theology), I have never seen evidence for that. Most Baptists I run into feel free to accept communion anywhere and consider such to be a valid partaking of communion, though they would avoid attending the church of an avowed heretic in the first place. I think that donatism would be more an issue with those breaking off from TEC. Indeed, I have witnessed donatistic statements by those expressing discontent with TEC from within a TEC parish. I say “weakly uses” sacramental theology, because I have often heard Baptist pastors refer to the ordinances as “sign, seal, and symbol”. What is that, if not sacrament? It’s smoke and mirrors, in reality. Make the equation: Baptist infant dedication = Catholic baptism and Baptist baptism = Catholic confirmation, and from a secular anthropological standpoint at least, when you think in terms of rites of initiation and rites of passage, you’ve got pretty much the same stuff going on. And maybe refusal to give credit to the above equations is a sort of Donatism? Are we really ready to disparage Baptist rites because theirs are defined differently and have somewhat different theological content than Anglican ones, which in turn have different content than that of Roman Catholics? Ditto for Baptist (or Presbyterian) ordination? Again I’m being general rather than specific to your post: I’ve seen far too much anti-Baptist sentiment in Anglican circles, much of it based upon ignorance. Siangombe Musing [196] Posted by Siangombe on 11-23-2008 at 05:07 PM · [top] Siangombe, we don’t go to church to have someone tell us what Baptists believe. Many of us aleady know more than we want to about what Baptists believe. We go to church to worship God, and to learn how to apply Christian beliefs to our daily live. That’s why we go to the Anglican Church. [197] Posted by GB on 11-23-2008 at 05:41 PM · [top] This has been a long thread, and I must admit that I have not read every comment, so I apologize if my question seems redundant or overly simple. Does the Diocese of Sydney advocate a belief in the Real Presence, or not? If not, then might I suggest that the problem can be solved by the Diocese shift to using Morning Prayer. Any lay person can officiate at the Daily Office, and the effect of this versus a lay lead “communion” would be exactly the same. [198] Posted by Sacerdotal451 on 11-23-2008 at 06:28 PM · [top] #198—a very good idea. If they really are orthodox, that is exactly what they will do. [199] Posted by GB on 11-23-2008 at 06:45 PM · [top] GB: Siangombe, we don’t go to church to have someone tell us what Baptists believe. Many of us aleady know more than we want to about what Baptists believe. We go to church to worship God, and to learn how to apply Christian beliefs to our daily live. That’s why we go to the Anglican Church. True, but this is a discussion board, and as indicated previously, I was not just responding to you. As for me, I am curious about what other denominations and religions believe, and I don’t mind discussing it in church, because it tends to sharpen my own beliefs. Worship is more than piety, than sitting in a pew and working one’s way through the BCP. It’s also about study and service. Today’s gospel reading, about the King being found through service to his subjects, is indicative of that. [200] Posted by Siangombe on 11-23-2008 at 07:16 PM · [top] #198 My understanding is that this is not being proposed because there are not enough presbyters to preside. It is being proposed because many folks in Sydney think it is theologically appropriate. Sydney’s eucharistic theology seems closer to the, so called, real absence than real presence. (In this they stand nearer to the early Anglican reformers than most contemporary Anglican eucharistic theology). There’s a new book on Cranmer’s eucharistic theology which may help in understanding the view of the eucharist that underlies Sydney’s discussions. [201] Posted by driver8 on 11-23-2008 at 10:10 PM · [top] GB, I think the point Siangombe was trying to make in his first comment (#194) is that even Baptists look to their ordained ministers to preside over Communion services and the deacons to assist in the distribution. The fact that even those who don’t believe in any concept of real presence, and who take a strictly memorialist view of the Lord’s Supper, have enough reverence for what is happening there to have ordained clergy preside over it is certainly an lesson from another tradition that Anglicans should find instructive. [202] Posted by ToAllTheWorld on 11-23-2008 at 10:56 PM · [top] It may be just ‘bread’ and just ‘juice’, but it ain’t just ‘supper’. I can not imagine a Baptist layman thinking to preside at a Lord’s Supper Service at Church. And you folks are telling me that Anglicans are planning to do so (Inconceivable). [203] Posted by Bo on 11-23-2008 at 11:26 PM · [top] Sydney’s eucharistic theology seems closer to the, so called, real absence than real presence. (In this they stand nearer to the early Anglican reformers than most contemporary Anglican eucharistic theology). Well no, not quite. For Christ is present by faith in the Supper. You are quite right that we stand far nearer to the early Anglican reformers than most contemporary Anglican Communion theology. But is that really a bad place as an Anglican to stand (or sit, or kneel - however you receive the elements )? After all, our official doctrine is the doctrine of those reformers. The body of Christ is given, taken, and eaten in the Supper, only after an heavenly and spiritual manner. And the mean whereby the body of Christ is received and eaten in the Supper is Faith. (Article XXVIII) The Prayer of Consecration functions in the same manner. We are reminded consistently that this is a memorial (both in the preamble and the words of institution) and that the elements are creatures (ie created). In the administration, there is a clear distinction made between the true body and blood of Christ, on which we feed by faith in our hearts, and the elements given to us which prompt us to “Take and eat this in remembrance that Christ died for thee”. There is the notion of memorial once again. It is not that there is no presence, but there is no presence in the elements. Rather they remind us of our Lord’s body and blood and so we feed on Him by once more placing our faith in Him and, in particular, His death on our behalf. He is, thus, very very really there - as real as any time anyone places their faith upon Him and all the more so (if it were possible) since this is a sincere deliberate act. That is, it seems to me, the plain understanding of the doctrine of the Anglican Reformers, as set out in the Articles and Prayer Book. I am not sure why, then, it should be considered somehow wrong for an Anglican to hold such a position, let alone be described as “unAnglican”. [204] Posted by David Ould on 11-24-2008 at 12:35 AM · [top] Come on David give me at least a tiny space for humour - the “real absence” has always brought a smile to my face. Once we begin to get into the ways in which Christ is present - sacramentally (as I would say) or by faith (as you say) - or the way in which the sacrament functions as a sign - we’d be nuancing our comments forever with little opportunity for cheap gags. I think the issue is that the reformers theology is not one with which many Anglicans agree. Is there to be space for sacramental Anglicans (for want of a better phrase) in the Anglican family? [205] Posted by driver8 on 11-24-2008 at 01:06 AM · [top] Come on David give me at least a tiny space for humour - the “real absence” has always brought a smile to my face. Yes, forgive me. I had actually noticed it and appreciated it. I also just used it as an opportunity to set a few things out Once we begin to get into the ways in which Christ is present - sacramentally (as I would say) or by faith (as you say) - or the way in which the sacrament functions as a sign - we’d be nuancing our comments forever with little opportunity for cheap gags. of course, and don’t stop! I think the issue is that the reformers theology is not one with which many Anglicans agree. Is there to be space for sacramental Anglicans (for want of a better phrase) in the Anglican family? Yes, I’m sure there is a space, although (as Richardson is quoted in noting above) it strikes me as being a rather ill-fitting space. I am merely objecting in the strongest possible terms to being told that my sacramental theology is somehow wrong as an Anglican, when it’s simply the theology of the Anglican Articles and Prayer Book!!! [206] Posted by David Ould on 11-24-2008 at 01:15 AM · [top] Yes, your sacramental theology is, given the little we’ve discussed, in broad continuity with the Anglican reformers. (Less so with Luther, perhaps but Luther and the Reformed folks never could quite come together on the sacraments). It’s profoundly discontinuous with much Anglican theology that was thought to represent where the Communion stands now on matters sacrmental, e.g. ARCIC. What did Anglicans in Australia do with the various ARCIC reports - was there a response by the whole church? [207] Posted by driver8 on 11-24-2008 at 01:30 AM · [top] Sydney Diocese has repeatedly rejected those reports where they have contradicted the stated position of the Church, ie the Articles and PrayerBook [208] Posted by David Ould on 11-24-2008 at 01:47 AM · [top] I should also say that ISTM that the COE (my church or origin) is much more theologically diverse than big chunks of TEC. Evangelicals are threaded through most COE dioceses and are a very visible theological presence. In big chunks of TEC, at the clerical level, evangelicals are almost completely absent. Several times, I’ve heard TEC bishops and clergy refer to pretty standard evangelical theology as unanglican. (“Fundamentalist” is the preferred term of abuse). Now you know I disagree with you but I’ve been friends with enough evangelical clergy in England to know that your (terribly wrong) views are very often squarely within the Anglican tradition. (Lay presidency being the glaring exception). [209] Posted by driver8 on 11-24-2008 at 01:51 AM · [top] Now you know I disagree with you but I’ve been friends with enough evangelical clergy in England to know that your (terribly wrong) views are very often squarely within the Anglican tradition… Does that not strike you as a rather perculiar thing to state? My position is “within the Anglican tradition”, although terribly wrong. Yet that “terribly wrong position” is the same as the constitutionally defined position of vast portions of the Anglican Communion! ...Lay presidency being the glaring exception Well, of course. :-D [210] Posted by David Ould on 11-24-2008 at 02:35 AM · [top] Well it’s strange if you expect Anglicanism to be church (or collection of churches) with a single predominant theology. It’s that, I’m denying. Anglicanism has been a contested theological territory since at least the 1620s. I can recognize that you faithfully represent one major strain in that dialogue. It happens to be one with which I disagree in some significant ways but it would be untruthful and lacking in charity not to recognise that the folks I disagree with are not Anglicans too. (Oops double negative - I hope you get by gist). Indeed one might say that Anglicans greatest achievement has been to hold in one Communion almost all the main strains of western theology. It is also Anglicanisms greatest weakness. I [211] Posted by driver8 on 11-24-2008 at 02:43 AM · [top] it would be untruthful and lacking in charity not to recognise that the folks I disagree with are not Anglicans too. Yes, I entirely agree. Which is my point - that I am often incredulous to be accused of holding an unAnglican position. Those in my position have more right than many others to claim the label Anglican. [212] Posted by David Ould on 11-24-2008 at 02:49 AM · [top] Yes, I entirely agree. Which is my point - that I am often incredulous to be accused of holding an unAnglican position. Those in my position have more right than many others to claim the label Anglican. I agree with you that we should look to the reformers to find “authentic Anglicanism” (sorry Anglo-Catholics). And I agree that you would fit with them better than many people posting here. But I don’t think that you would fit perfectly. Reading the Homilies, Cramner, Jewel, Hooker etc. it is clear that they placed a very high regard on the early Church fathers (though admittedly less of a regard than they placed on scripture). Jewel’s main point, from what I recall (with which I agree) was that the Church of England was more in line with that of the fathers than the Roman Catholicism of his day. In the homilies, they continually write things such as Neither proved by warrant of scripture or in any of the ancient writers’ (not an exact quote, I’m working from my rather dodgy memory). Hooker wrote against the puritans who wanted to have the reformation move beyond merely stripping out the unscriptural practices of Popery. Yet you seem to hold no regard for their writings; none at all, not in the least, absolutely nothing - at least when they disagree with you on a matter about which you claim that scripture is silent. You might agree with the reformer’s theology (although I’ve always read the BCP and articles as following Calvin’s Eucharistic theology rather than Zwingli’s) in most matters, but not, I think, in their underlying methods which was to regard the fathers as well as the (more important) scripture (and that others make the more serious error of raising the fathers too high doesn’t negate my point); which is what has led you to propose this measure against the Anglican reformer’s BCP and ordinal. But you still haven’t answered my main point. If you cannot disprove Ignatius, Clement etc. from scripture, then you have to admit what they wrote is possibly correct (i.e. in line with God’s intention for the Church, which is ultimately the question we must be trying to answer; my sola scriptura, your solo scriptura, the catholic magisterium of the church etc. only being methods to find the answer to that question), including the dire consequences of a layman administrating the Eucharist (e.g. Apostolic Constitutions III. X: he shall suffer the fate of Uzziah). Why undertake such a risky venture when you cannot be certain by the only means that you seem to accept (direct proof from scripture) that your theology is well founded? [213] Posted by Boring Bloke on 11-24-2008 at 06:04 AM · [top] David, Yes, your low view of the Church and Sacraments is within the pale. It is lay presidency that is unanglican, something no reformers or Anglicans held to. Also, I must take exception to your effort to read Anglicanism through the lens of the Reformation as a whole. The Reformation period holds no authority over the Anglican Church. Only the Articles and the Ordinals do. They may have been produced in this period, but you cannot jump from this to the views of Cranmer to say that you are ‘more Anglican.’ The simple fact is that the Articles were written to allow for flexibility rather than rigidity in doctrine. And this is why you can hold to a low or high view of the Church and the Sacraments and remain Anglican. Lay presidency, however, has never been a part of the Anglican teaching or practice. It is simply unanglican (it is also inconsistent with the practice of Christians throughout the world). You can utilize Article 34 to justify this change, but I would use the same Article to call you to wait for the rest of the Communion so as not to fall prey to the ‘private judgement’ of one part of the Body at the expense of the Communion as a whole. I am still waiting for you to respond to any of my posts regarding your (lack of) concern for catholic order. [214] Posted by Rob Paris on 11-24-2008 at 08:56 AM · [top] Thank you, driver8. The doctrine of the real absence is one I will have to remember. [215] Posted by GB on 11-24-2008 at 09:19 AM · [top] The simple fact is that the Articles were written to allow for flexibility rather than rigidity in doctrine. I’m not so sure how flexible the 39 articles are. They strike me as being much more Reformed than the everyday orthodox Anglican would be comfortable with. And as to AngloCatholics, I don’t think they would particularly like this part of Article XXV: The Sacraments were not ordained of Christ to be gazed upon, or to be carried about, but that we should duly use them. [216] Posted by Siangombe on 11-24-2008 at 09:37 AM · [top] Siangombe, it isn’t the “gazing upon” or “carrying about” that is important to me so that part of Article XXV isn’t particularly worrisome. But I think “Anglo-Catholic” is a descriptor that is at times being packed with meanings that don’t exactly fit. [217] Posted by oscewicee on 11-24-2008 at 09:52 AM · [top] Siangombe, it isn’t the “gazing upon” or “carrying about” that is important to me so that part of Article XXV isn’t particularly worrisome. What about the vigils or monstrances in the presence of the reserved host? [218] Posted by Siangombe on 11-24-2008 at 10:25 AM · [top] Davil Ould, I disagree with all of your arguments in favor of lay and diaconal presidency, as well as much of what you apparantly believe about the nature of the church. that said, I want to thank you for the calm, gracious, manner in which you have stated your position and answered your critics. Your unfailing civility is an example to us all. [219] Posted by evan miller on 11-24-2008 at 11:00 AM · [top] Obviously, should have been “David”. Need to get the heat fixed. My fingers are cold. [220] Posted by evan miller on 11-24-2008 at 11:02 AM · [top] The Sacraments were not ordained of Christ to be gazed upon, or to be carried about, but that we should duly use them. As an Anglo-catholic, I wholeheartedly agree with this statement. To take just the Eucharist (since I think we’d all agree that that is the sacrament in question here) I think we’d all agree that the purpose of the Eucharist is Communion with our Lord by receiving the Body and Blood. I.e., the Eucharist was “ordained of Christ” so that “we should duly use” it by receiving it. But I don’t see anything in the literal meaning of the article that prohibits additional devotions: it simply states that those devotions are not the purpose for which it was instituted; i.e., eucharistic devotions should not take the place of receiving the Holy Communion—which had in fact happened in the medieval church against which the reformers were protesting. And, if one is able to accept the words of Christ, “this is my Body,” “This is my blood,” and “whosoever eats my flesh and drinks my blood abides in me and I in him” etc. without resorting to the contortionistic eisegesis necessary to maintain that He didn’t really mean what He said, the Eucharist is necessarily the center and focal point of the Christian life . . . and one might think that as such additional devotions surrounding it are a natural and even a healthy development, so long as they do not undermine the purpose of Christ in instituting the sacrament, which is what makes it so central to the Christian life in the first place. [221] Posted by tk+ on 11-24-2008 at 11:59 AM · [top] Ould quoted the following: “The body of Christ is given, taken, and eaten in the Supper, only after an heavenly and spiritual manner. And the mean whereby the body of Christ is received and eaten in the Supper is Faith.”(Article XXVIII) It should be noted Rev. (or, Deacon?) Ould, what Bishop Guest (who was a primary author of this particular portion of the 28th Article and who was also one of the Bishops who revised the 1552 BCP to the standard 1559 BCP) states regarding this Article: “I told him plainly that this word only in the foresaid Article [Article 28] did not exclude ye presence of Christ’s Body from the Sacrament, but only ye grossness and sensibleness in ye receiving thereof: For I said unto him though he took Christ’s Body in his hand, received it with his mouth, and that corporally naturally really substantially and carnally as ye doctors do write, yet did he not for all that see it, feel it, smell it, nor taste it.” “Then ye may saye it in ye Sacrament His very Body is present yea really that is to saye, in deede, substantially that is in substance, and corporally carnally and naturally, by ye wich words is ment that His verye Bodye His very flesh and His very humane nature is there not after corporall carnall or naturall wise, but invisibly unspeakeably supernaturally spiritually divinely and by waye unto Him onlye knowen.” Continued on following post [222] Posted by William on 11-24-2008 at 12:43 PM · [top] Continued from above Now, Bishop Guest initially objected to the later inclusion (almost 10 years later) in the 39 Articles of St. Augustine’s statement on the wicked not feeding on Christ in the Sacrament in the newly added Article 29—because of the concern of a possible denial therein of Christ’s “spiritual, heavenly” presence in the Consecrated Elements—but he withdrew this initial objection within a few days. Of course, Article 29 does not deny the presence of Christ in the Eucharist. Rather, it simply affirms with St. Augustine and others that regardless of whether the Sacramental presence of Christ may be said to come in judgment with the Sacrament into the wicked or not, yet His Sacramental presence is not truly feed upon, that is, in the soul/heart or “inwardly” (as St. Augustine says—on the authority of the Gospel of John iteself: “He that eats my flesh, and drinks my blood, dwells in me, and I in him.” This it is, therefore, for a man to eat that meat and to drink that drink, to dwell in Christ, and to have Christ dwelling in him. Consequently, he that dwells not in Christ, and in whom Christ dwells not, doubtless neither eats His flesh [spiritually] nor drinks His blood [although he may press the sacrament of the body and blood of Christ carnally and visibly with his teeth], but rather does he eat and drink the sacrament of so great a thing to his own judgment, because he, being unclean, has presumed to come to the sacraments of Christ, which no man takes worthily except he that is pure: of such it is said, “Blessed are the pure in heart, for they shall see God.” Matthew 5:8 And St. Augustine states further (and the BCPs words “...feed on him in thy heart by faith with thanksgiving” seem to have likely been derived from the following statements of St. Augustine). “This, then, is the bread that comes down from heaven, that if any man eat thereof, he shall not die.” But this is what belongs to the virtue of the sacrament, not to the visible sacrament; he that eats within, not without; who eats in his heart, not who presses with his teeth.)). 11…Moses ate manna, Aaron ate manna, Phinehas ate manna, and many ate manna, who were pleasing to the Lord, and they are not dead. Why? Because they understood the visible food spiritually, hungered spiritually, tasted spiritually, that they might be filled spiritually. For even we at this day receive visible food: but the sacrament is one thing, the virtue of the sacrament another. How many do receive at the altar and die, and die indeed by receiving? Whence the apostle says, “Eats and drinks judgment to himself.” 1 Corinthians 11:29 As for Cranmer it was the historic witness of the Monk/Priest Rathumnus in the 9th century (and apparently—in particular—the teaching of the Church Fathers which Rathumnus brought forward) that was foundational in his later understanding of Holy Communion (now one might validly question whether Cranmer always applied the Church Fathers accurately on the Eucharist—but he made it clear to the end of his life that his intention was to teach no other doctrine than the Church Fathers themselves had taught (explicitly submitting himself to the testimonty of the Church Fathers on the Eucharist to the end of his life), and that the Church Fathers—drawn to his attention most notably by Rathrumnus—were foundational in coming to his later views on the Eucharist). Rathumnus’ excellent exposition on the Sacrament can be read here (though a number of Anglicans interpreted him in a more “receptionist” or “virtualist” sense in my opinion his views accord better with the presence of Christ (after a “heavenly or spiritual manner”) in the Consecrated Elements held by a number of the Anglican Divines): http://books.google.com/books?id=we8CAAAAQAAJ&pg=PA1&dq=bertram+“concerning+the+body+and+blood”#PPA1,M1 Blessings in Christ. William Scott p.s. The “receptionist”/”virtualist” position itself is actually similar to some of the views maintained among Eastern Orthodox on the presence of Christ in the Sacrament. [223] Posted by William on 11-24-2008 at 12:44 PM · [top] I realized after posting I should have been more clear…the ‘flexibility’of the Articles is in relation to the other Reformed confessions and articles that were being promulgated at the time. They retain a decidedly Reformed leaning, but they stop far short of what was being promoted on the Continent, which helps to demonstrate that you cannot simply read the times into the Articles. They were intentionally creating room for those who would not go so far as the Continental Reformers. I did not mean that they are ‘loose’ as in ‘lacking conviction.’ [224] Posted by Rob Paris on 11-24-2008 at 03:09 PM · [top] I want to thank you for the calm, gracious, manner in which you have stated your position and answered your critics. Your unfailing civility is an example to us all. You are, perhaps, a little too kind, Evan. I don’t think I’ve been unfailingly civil and for that I apologise. Nevertheless, thanks for your kind words. [225] Posted by David Ould on 11-24-2008 at 05:13 PM · [top] But you still haven’t answered my main point. If you cannot disprove Ignatius, Clement etc. from scripture, then you have to admit what they wrote is possibly correct I still have absolutely no idea why I need to disprove them! Ignatius, Clement and even Athanasius may all have written strongly on the subject and, indeed, have helpful things to say but derive our doctrine from Scripture. What cannot be established from Scripture cannot be demanded of anyone to believe or even disprove. What is established in the New Testament is:
1. Leadership of congregations by the episkopos/presbyter. Their prime function was to teach the gospel in the word. No mention is ever made of their specific duties with respect to the Lord’s Supper
2. A fulfilment of the OT priestly functions in the high-priesthood of the Lord Jesus Christ and the priesthood of all believers
3. The Lord’s Supper in remembrance of His death
Beyond that, Scripture has next to nothing to say about the current debate and so I will, with the greatest respect, not consider myself bound by extra-Scriptural sources, however helpful they may be. Nor should I, since in Scripture we have everything that is required. It would be wrong of me to be bound in doctrine to more than that, both as an Anglican (by virtue of our Articles) and (more importantly) as a Christian man by virtue of my allegiance to the One who gave us those sufficient Scriptures in the first place. [226] Posted by David Ould on 11-24-2008 at 05:20 PM · [top] Yes, David, we know you are a Christian. And please remember that we are, also. As such, a mutual respect for one anothers’ key theological beliefs would seem to be in order. Surely, you should realize by now that your proposal for lay presidency crosses a line that is intolerable for most orthodox Anglicans—give it up, and let us have some peace, please! [227] Posted by GB on 11-24-2008 at 07:18 PM · [top] I have thought for a number of years that a deacon’s mass was permissible in the absence of a priest. The host administered by the deacon would be previously consecrated and taken from the aumbrey. Of course, lay administration is something altogether different. James Kennish [228] Posted by jaroke on 11-24-2008 at 09:05 PM · [top] Matthew 26: 26 Now as they were eating, Jesus took bread, and after blessing it broke it and gave it to the disciples, and said, “Take, eat; this is my body.” 27 And he took a cup, and when he had given thanks he gave it to them, saying, “Drink of it, all of you, 28 for this is my blood of the covenant, which is poured out for many for the forgiveness of sins. 29 I tell you I will not drink again of this fruit of the vine until that day when I drink it new with you in my Father’s kingdom.” Mark 22: 22 And as they were eating, he took bread, and after blessing it broke it and gave it to them, and said, “Take; this is my body.” 23 And he took a cup, and when he had given thanks he gave it to them, and they all drank of it. 24 And he said to them, “This is my blood of the covenant, which is poured out for many. 25 Truly, I say to you, I will not drink again of the fruit of the vine until that day when I drink it new in the kingdom of God.” Luke 22: ‘14 And when the hour came, he reclined at table, and the apostles with him. 15 And he said to them, “I have earnestly desired to eat this Passover with you before I suffer. 16 For I tell you I will not eat it until it is fulfilled in the kingdom of God.” 17 And he took a cup, and when he had given thanks he said, “Take this, and divide it among yourselves. 18 For I tell you that from now on I will not drink of the fruit of the vine until the kingdom of God comes.” 19 And he took bread, and when he had given thanks, he broke it and gave it to them, saying, “This is my body, which is given for you. Do this in remembrance of me.” 20 And likewise the cup after they had eaten, saying, “This cup that is poured out for you is the new covenant in my blood.’ 1 Corinthians 11: 23 For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread, 24 and when he had given thanks, he broke it, and said, “This is my body which is for you. Do this in remembrance of me.” 25 In the same way also he took the cup, after supper, saying, “This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.” 26 For as often as you eat this bread and drink the cup, you proclaim the Lord’s death until he comes. Folks, Correct me if I’m wrong, but I find no warrant in scripture for anything other then for ‘lay presidency’. So in accordance with scripture I am under obligation to Christ to remind my family, or anyone else I’m with, at each and every meal of Christ’s sacrifice for us. Unlike ‘the Passover meal, that occurred once a year, Christ instituted a replacement that covers each and every meal we partake of. In other words, remembrance and proclamation of Christ’s sacrifice is not limited to what we do in a formal ‘Church’ setting, and only if we have someone present with a dog collar! Christ is Lord of all of Life, so his commands cover all of life, not just when we are in a ‘special building, on one day a week, and with ‘specially’ designated people there. Your free to hold your own opinion, but I confident to stand before our Lord on the last day on this one. [229] Posted by HughBP on 11-24-2008 at 09:17 PM · [top] Yes, David, we know you are a Christian. And please remember that we are, also. I do not recall suggesting anywhere on this thread anything like that. As such, a mutual respect for one anothers’ key theological beliefs would seem to be in order. Well of course, but respecting is not the same as agreeing. Surely, you should realize by now that your proposal for lay presidency crosses a line that is intolerable for most orthodox Anglicans—give it up, and let us have some peace, please! Well, a couple of things. It’s not my proposal. I did, however, set out to explain to readers here is the reasoning behind the decision of Sydney’s synod to take this decision. Now, there may have been a line crossed that is intolerable for others. What I have been pointing out, however, is that that line is not set by Scripture and so your (and others) demands that I give “peace” or whatever else it may be is not a demand that can be laid upon a Christian, let alone an Anglican, since it’s basis is not from Scripture. Now, complain all you like about Sydney’s position - you are free to do so. But when you demand that people of such a mind adhere to an authority that is not that of Scripture, well then you cannot expect not to have others disagree with you. [230] Posted by David Ould on 11-24-2008 at 11:01 PM · [top] David, I can only say “no comment”. [231] Posted by GB on 11-25-2008 at 02:52 AM · [top] I still have absolutely no idea why I need to disprove them! I explained in my post #48/#49 above. What I am discussing is prudence; weighing up the possibilities with the benefits and risks that ensue to ensure that the action we take is the one most likely to edify the church (Article XXXIV, and if we cannot be certain, which on this subject we both agree we cannot because scripture gives no completely compelling answer either way, most likely’ is the best that we can do). If you cannot disprove them from scripture, you have to admit the possibility that they are right and that you are wrong with the devastating consequences that follow if you proceed. You wrote at the top of this thread that Ignatius’s writings aren’t infallible. Fine. I fully agree. Neither am I (by a long distance); Neither are you (by a considerably shorter distance); neither are the Professors at Moore’s college, and neither (though it pains me to write this, and I can sense your incoming missiles of accusation) were the reformers who wrote article VI. So we have to in humility ask ourselves who is the less likely to have made a mistake in interpreting Christ’s teachings: Somebody who learned the gospel from the lips of the apostle John, or somebody sitting at a computer nearly 2000 years later trying to piece everything together as best he can. And, turning from the Anglo-Catholic argument to the more familiar (to me) evangelical one, if you want a scriptural argument not mentioned so far (I think, I’m not going to reread this whole thread to check). As Paul wrote, even if something is permissible, that does not make it beneficial or, in the word of article XXXIV, edifying. Now turn to the first verses of Acts chapter 6. Deacons were appointed to wait on tables’ to enable the apostles to concentrate on their duties. Now you, as a deacon, want to take over (against article XXIII) the presbyterial duties (as defined in article XXXVI via the BCP ordinal): leading the congregations, preaching, administrating the sacraments. So when you spend all your time doing that, who will be there to ensure that the Greek widows get their share? Or are you saying that you and all your fellow deacons in Sydney can do what was too much for the apostles? Or that tending to the needs of the Greek widows is unimportant and not something that the Church ought to worry about? [232] Posted by Boring Bloke on 11-25-2008 at 05:09 AM · [top] As to whether the Sydney innovation has any claim to being “more” representative of being a scripturally led church, I probably should make no comment other than to throw up my hands. The Sydney argument or at least what David has presented here in that regards seems to me to categorically ignore the the context of both Scripture and Article so that one’s own intentions might be followed. The worshipping church wrote Holy Scripture and has things to say about what it is that they mean. This is why we are accountable to men such as Ignatius of Antioch, Clement of Rome and others here who knew the apostles. For that matter, the logic of David’s argument places his reading of, for instance, the Gospel according to John above that of what the gospeller might say about this gospel. I read part of this as naivete and part as pure self-willed cussedness. Post #229’s twist on the Eucharist can equally (poorly and wrongly) be drawn from scripture according to your standards ... that what we are talking about is simply that we are supposed to pray a little ditti every time we eat to remember what came before.By my lights, this argument does for the Bible what the Medieval Schoolmen (Scholasticism) did to the Sacraments ... carrying it about and adoring it without participating in it. It is indeed a doctrine of Real Absence and a proclamation that Jesus is not present in the Sacraments. I don’t know if David or the Diocese of Syndey accompanies this error with likewise a doctrine of Baptism that denies the gift of the Holy Spirit therein ... but if so, then in intent, though you use water and say the right words, you do not mean what the Church means and you are no Christian but have established your own religion which is worship of the Bible. If the doctrine of Transubstantiation comes close to a magical understanding of physics and theology to make of the Eucharist something akin to cannibalism, Zwingeli makes of the Eucharist something so merely symbolic that it approaches a neo-Gnosticism. This has been one of the shortcomings of theology often heard in TEC these days. I recall people arguing that the ELCA-ECUSA Concordat was going to make both more Christian! The ELCA had belief in the Bible to bring whilest the ECUSA had the outward form of laying on of hands to offer. This seems to be the ecumenicism of Anglicanism today which is to bring the crumbs under the table back together and declare it a loaf ... rather than breaking bread together. Throw an Eastern Orthodox icon (of Malcolm X) on the wall and call it ecumenicism. I am alternatively heartened and disheartened for the hope of the Anglican Communion becoming a church as I read through this thread. [233] Posted by monologistos on 11-25-2008 at 06:37 AM · [top] Recalling the story of the road to Emmaus: it is Christ’s PRESENCE that brings Scripture to life. This is revealed in the breaking of the bread. It is a mystery of our faith. If Jesus is not present, His Body is not present. It is time that Sydney grapples with theology of sacrament ... failure to do so will lead inevitably to departure from the Anglican Communion. It may be that this is inevitable for they seem to have their own gospel apart from the gospel known to the Fathers (or Ecumenical Councils) who wrote, collected and canonized Scripture. It should be added that by these standards that David puts forth, there should be no special pleading for the Apostles’ or Nicene Creed ... OR for the 39 Articles. [234] Posted by monologistos on 11-25-2008 at 06:56 AM · [top] Regarding worship of the dead letter, that’s like saying we know John the Baptist because we have his body. Without the head attached, it is hard to know much about the man though you may rifle his pockets. [235] Posted by monologistos on 11-25-2008 at 07:06 AM · [top] Sydney’s action and the discussion in this thread is a replay of the controversies leading to the Elizabethan Settlement. Sydney (and apparently Deacon Ould) seek to undo the Elizabethan Settlement in favor of the a more radical Protestant view. The questions regarding the theology of the Church Fathers and the way the authority of Scripture are critical questions - the answers are significant in defining the differences between Protestant denominations. I think for many on this forum a more profitable questions is: Does the Elizabethan Settlement define Anglicanism? Does Anglican mean Apostolic, Catholic, and Reformed? What is lost if means only one (Reformed) or a combination of just two? Admittedly, there is some tension between these three perspectives, but it was has been that all three are necessary and essential to Anglicanism. If Sydney wishes to undo the Elizabethan Settlement, then it is fair to question whether it should continue to be considered Anglican. BTW, by placing the Elizabethan Settlement at the center of Anglican identity the work of the Caroline divines, who were responsible for making the Settlement work, becomes very significant. sy [236] Posted by Tractarian on 11-25-2008 at 07:45 AM · [top] David, several times you have said, “What cannot be established from Scripture cannot be demanded of anyone to believe or even disprove.” However, the Church can demand things of you that are not established in Scripture in order to maintain order. As Anglicans, we believe that tradition—especially Apostolic tradition—is important to consider, and it is largely on the basis of that tradition that we have established the church order we have. If you don’t want to keep to that church order, then you may be Christian but you are certainly not being faithful to Anglicanism. You remind me of a teenager who rebels against his parents, saying, “Why do we have these rules, and not others more to my liking?” As my dad used to say to me when I was a teenager, “Son, you need to learn to act like you have a family!” [237] Posted by Hindustaaniwalla Hatterr on 11-25-2008 at 08:30 AM · [top] monologistos, I think you and Paulinus are both correct. The Sydneyites are very close to establishing a new denomination (if not a new religion) which is focused on anti-Catholicism, and does worship the Bible more than the God who is in the Bible. Undoing the Elizabethan Settlement is exactly what they are talking about. So why do they continue to quote the Articles of Religion as if they are some type of authority on a par with Scripture? Most of the commentators which I have read who go to this same extreme will also reject the Articles as being too catholic. (Believe it or not.) [238] Posted by GB on 11-25-2008 at 08:31 AM · [top] And BTW, very few people so far have had opportunity to examine the prayerbook edition published by the Anglican Catholic Church—the Articles of Religion are still there just as originally written. [239] Posted by GB on 11-25-2008 at 08:50 AM · [top] Amen to 236 and 237…the church has authority in matters of controversy (20) and private opinion shall be bound by church order (34). Nothing is to be required for salvation that is not proved from scripture (6), but much may be required for church order so long as it is not contrary to scripture (34). This is the point I keep putting before David, but he has, as yet, failed to acknowledge this as the clear teaching of the Articles, which he has upbraided others for not upholding. Lay presidency is not a matter of doctrine, but of order. Also, church leadership is often in the plural in the New Testament, not the singular. So, if you want to make the case that you are being ‘more biblical’ rather than following tradition, in your understanding of the church government, you need to abandon the claim that priesthood is tied to rectorship. This appears to be driving the need for lay presidency and is a bizarre and local tradition of Sydney that has no basis in scripture whatsoever. [240] Posted by Rob Paris on 11-25-2008 at 10:20 AM · [top] GB, when I was an Episcopalian, daily faced with the slide into apostasy everywhere rampant, I tended to argue against setting up the Articles as a kind of Anglican Confessional regardless of their historical significance in keeping the peace at a very difficult time in English history. I argued against them on two grounds in particular despite the many really wonderful things to be found therein. First, I said, we ought to be a creedal church rather than a confessional church. I still think in that distinction, Anglicanism might find great profit. Second, I find them overly Calvinist. Still, while arguing for membership in the one, holy, catholic and apostolic church, I would often cite the articles as a moderating authority. I would cite the language of metaphysics in claiming an ontological change takes place during ordinations/consecrations against a merely functional view of orders as found within Methodism, for example. Much of this dialog has been formed within the tension between Catholicism and Protestantism and our understanding of the issues themselves begins with this period. However, it was not so from the beginning. All these issues are taken up by the early church but within a different context. Read the ecumenical councils. For that matter, read the writing of Ignatius of Antioch. Read the writing of Clement of Rome. But even more than these, look at their manner of living and dying and ask if it bears testimony to the Good News and to the Holy Spirit. The self-emptying of Christ is the divine humility. The self-emptying (kenosis) of the Holy Spirit is that the Spirit bears witness to the Second Person and not to Himself. Christ bears witness to the Father. Who then bears witness to the Holy Spirit? I would argue that it is the lives of the saints. Look then to the testimony of the lives of the saints throughout the past two thousand years of the church. You cannot participate fully without discerning the Body. The Body of Christ isn’t only Reformed churchmen of the past half millenium. The attempt to leap over Tradition, which I would cite as the life of the Holy Spirit in the Church, back to the writers of the Canon over a millenium and a half is the leap of a New Age Religion. Mohammed did it. Joseph Smith did it. I would have the Diocese of Sydney not follow that mistake, even in part. To be part of the organic worship of the one, holy, catholic and apostolic church gives us the same spiritual resources and hearkens to the one dispensation of the Holy Spirit.I have a question that might address the question of orders. How do you understand the gift of the Holy Spirit given by the Risen Lord to the disciples as he breathed upon them versus the gift of the Holy Spirit at Pentecost. Might the first be the general gift and the second a specific empowering? Seems counterintuitive at first but I would encourage you to prayerfully take a look at this idea. [241] Posted by monologistos on 11-25-2008 at 10:43 AM · [top] Monologistos, Look then to the testimony of the lives of the saints throughout the past two thousand years of the church. You cannot participate fully without discerning the Body. The Body of Christ isn’t only Reformed churchmen of the past half millenium. The attempt to leap over Tradition, which I would cite as the life of the Holy Spirit in the Church, back to the writers of the Canon over a millenium and a half is the leap of a New Age Religion. Mohammed did it. Joseph Smith did it. I would have the Diocese of Sydney not follow that mistake, even in part. To be part of the organic worship of the one, holy, catholic and apostolic church gives us the same spiritual resources and hearkens to the one dispensation of the Holy Spirit. [241] Well stated. [242] Posted by Tractarian on 11-25-2008 at 10:49 AM · [top] The attempt to leap over Tradition, which I would cite as the life of the Holy Spirit in the Church, back to the writers of the Canon over a millenium and a half is the leap of a New Age Religion. Mohammed did it. Joseph Smith did it. So did the founder of the Jehovah’s Witnesses, and how many others? [243] Posted by oscewicee on 11-25-2008 at 10:57 AM · [top] Oscewicee, so did the Campbellites. In their proper appreciation for the early church, they attempted to begin again with the apostles and made it about as far back as the Nineteenth Century ... their own day. There is a mistaken notion that the disciples were primatives who invented liturgy, scorned architecture, and had “house church” which was invented afresh by every father of the house. The disciples in Jerusalem continued to worship in the Temple until it’s destruction. We are the inheritors of Jewish worship traditions and all of the apostles were worshipping Jews. The prototypes of the sacraments are also present in Judaism of that time. Granted, we do not make it dogma in the sense of necessary for belief that one might be an inheritor of the Kingdom of Heaven that one believe in three seperate but equal orders or especially in pietistic traditions (small t) such as the assumption of Mary’s body or papal infallibility. But the Church may establish house rules for the ordering of the Body. The Church may authorize the use of it’s power as granted to the Church by Christ and the Spirit…not simply as it sees fit but according to “Lex orandi, lex credendi”. I would argue that the Church does not say where the Holy Spirit cannot act but it does say where it does. We worship what we know. We know that we receive our Lord in Eucharist. The Eucharist is the central and formative act of Christian worship as the Church. The Ekklesia, those called apart by God, gather to be the Church ... for Eucharist. Attempts to make that into a legalistic formula may fall short on a variety of grounds. Rubrics do not themselves guarantee the Real Presence and yet the Church is obliged to define rubrics. If they do not, pretty soon someone will be substituting Chicken ala King for bread, milk for wine, and preaching on Jesus our Mother Hen. The preface to the Ordinal clearly defines apostolic succession by laying on of hands. This house rule defines for us where we know the Church is. Even as church doctrine was often defined in reaction to error the early community defined leadership in reaction to false teachers, false prophets. By the time of Ignatius around 110, the two emergent systems of communities led by presbyters and communities led by bishops with deacons was combined into the monarchical episcopate with assisting presbyters ... and deacons assigned by the bishop with that important element of the kerygma of the Gospel that involves feeding the hungry, clothing the naked, etc. No doubt there were variations in places but the exception does not make the rule. Many exceptions were rank heresies. It would be something of a category mistake to say we don’t believe in a monarchical episcopate because we believe in the Bible. Similarly, I think it is a mistake to take the scriptural use of heiros (applied to Christ, to the Aaronic priesthood and to the priesthood of all believers) and then say that the priesthood of all believers is the same thing as every believer is a priest. Every believer is not Christ. Only as the Body of Christ are we the Church. The Church has authorized some men, acting with the authority of the Church, to speak on behalf of the Church which speaks the words of Christ Himself and speak the words of institution ... not as Christ but for Christ. These men do not have the power of Christ and they do not become Christ. If it is not too much to try to say, I would venture to say that Christ is in heaven and thus while we liturgically live out a linear worship with moments such as the anemnesis and epiklesis, it is not a new sacrifice but a participation in the once for all actual event of the Incarnate Lord which stands at the center of time in eternity. [244] Posted by monologistos on 11-25-2008 at 12:26 PM · [top] ah, that was “hiereus” or sacerdos. My spelling is wack. [245] Posted by monologistos on 11-25-2008 at 12:43 PM · [top] #244 AMEN! [246] Posted by evan miller on 11-25-2008 at 01:11 PM · [top] I finally found the other reference I was looking for, translated from “The Decrees of the Ecumenical Councils” and being a canon from the 1st such council which took place in Nicaea in 325. Canon 18 (emphasis mine) : “It has come to the attention of this holy and great synod that in some places and cities deacons give communion to presbyters, although neither canon nor custom allows this, namely that those who have no authority to offer should give the body of Christ to those who do offer. Moreover it has become known that some of the deacons now receive the eucharist even before the bishops. All these practices must be suppressed. Deacons must remain within their own limits, knowing that they are the ministers of the bishop and subordinate to the presbyters. Let them receive the eucharist according to their order after the presbyters from the hands of the bishop or the presbyter. Nor shall permission be given for the deacons to sit among the presbyters, for such an arrangement is contrary to the canon and to rank. If anyone refuses to comply even after these decrees, he is to be suspended from the diaconate.” It begs the question—If GAFCON and FCA adhere to the first 7 Ecumenical Councils’s rulings, how then can Sydney be in compliance, or if somehow Sydney is in compliance, how then can FCA be said to adhere to the first 7 councils and at the same not do so? If Sydney’s position is that Sydney has, by whatever means, superceded or nullified this canon, then let Sydney clearly say this in so many words to the other members of the FCA. If the FCA’s position is that Sydney is in compliance, then let the FCA say to the world, “we deem canon 18 of the First Council of Nicaea to be nullified.” Then let the chips fall where they may. [247] Posted by Antique on 11-25-2008 at 01:51 PM · [top] monologistos, Paulinus, Boring Bloke and William - I just wanted to thank you all for your excellent posts on this thread. I appreciate your taking time to post in depth and so insightfully. [248] Posted by oscewicee on 11-25-2008 at 02:05 PM · [top] #248 I heartily concur. and oscewicee, your own contributions have been outstanding as well. Thank you all. [249] Posted by evan miller on 11-25-2008 at 02:30 PM · [top] 232: The Seven in Acts 6 were not called “Deacons.” Rather, they did diakonia, or “waited on tables” as part of their ministry. Granted, tradition grounds the diaconate in Acts 6. However, if you look at the ministry of the Seven, in Acts 7-8, their work is more apostolic than diaconal. Space does not permit a full exposition, but to summarize my own thinking: At the book-level discourse level, note this schema: (Acts 1: Choosing of Mattias through lots to round out the number of the Twelve.) Acts 6: Choosing of the Seven. Acts 7: The Passion of Stephen (greatly resembling Christ’s crucifixion) and his beatific vision in Paul’s presence. Acts 8: The Acts of Philip, carrying out the Acts 1 commission to “the ends of the Earth,” in the form of the Ethiopian, whom he baptizes. Acts 9: Paul’s (not so) beatific vision… ...and I claim that, in Luke’s editorial judgment, Paul replaces Stephen as one of the Seven! Note also the numerological parallel in the gospel of Luke, with the sending of the 12 (Matthew: exclusively to the Jews) and the sending of the 70, probably to Samaria and possibly to Idumea as well. Note also how the Lukan model for house to house mission in pairs is maintained by both Peter (and John) and Paul (and Barnabas, Silas) in Acts. If you want a model deacon (in fact the only deacon in the NT), I would suggest Phoebe in Romans 16. She was likely the leader of a house church who provided hospitality to the apostles, she was called a deacon, and she was also sent on mission to Rome representing Paul. [250] Posted by Siangombe on 11-25-2008 at 03:24 PM · [top] You’re claiming the apostles appointed other apostles to wait table for them? And that Paul was one of these waiters? [251] Posted by Bo on 11-25-2008 at 04:07 PM · [top] #250 ...and I claim that, in Luke’s editorial judgment, Paul replaces Stephen as one of the Seven! Funny. That’s not the claim Paul made for himself over and over and over again. [252] Posted by Fr. David McElrea (formerly farstrider+) on 11-25-2008 at 04:33 PM · [top] And why do you think Phoebe was “likely the leader of a house church”? Eisogete much? [253] Posted by Fr. David McElrea (formerly farstrider+) on 11-25-2008 at 04:35 PM · [top] The Sydneyites are very close to establishing a new denomination (if not a new religion) which is focused on anti-Catholicism, and does worship the Bible more than the God who is in the Bible This sort of accusation is entirely unnecessary and quite without foundation. If anti-Catholicism and Bibliolatry are the foundation of Sydney Anglicanism then it must be a different Sydney to the one I have spent 5 years in. It is, in fact, a slur on a great number of very godly men and women. [254] Posted by David Ould on 11-25-2008 at 04:37 PM · [top] David, The folks in Sydney seem determined to define a new order for the Church (well, it would be a new order for the Anglicans), an ‘authorized leader for the public celebration Lord’s Supper’ who is not ordained. Am I missing something? [255] Posted by Bo on 11-25-2008 at 09:41 PM · [top] 251: You’re claiming the apostles appointed other apostles to wait table for them? No. The Seven served Greek speakers. And they served them the same way the Twelve did for the Aramaic speakers. There is no indication that the Twelve stopped serving entirely. (That would have violated the Lord’s commands regarding serving, wouldn’t it?) The form that table service took could well have included presiding over worship. 252: I don’t see the conflict you are asserting. To Luke, he was an apostle. He saw the risen Christ. So did Stephen. Both could therefore be called apostles. Paul himself used “apostle” to describe people other than the Twelve. 252 (second post): You are mixing accusation with question. I would remind you of the “Before you post” rule on this website. The language about Phoebe indicates that she gave hospitality to Paul, as a householder. She had sufficient status and means in ministry that Paul made her an envoy to Rome. If she didn’t lead the church that met in her home, she certainly had a major say in who did. I refer you to House Church and Mission: The Importance of Household Structures in Early Christianity at http://tinyurl.com/64yj5o regarding the significance of the house church in the NT. [256] Posted by Siangombe on 11-25-2008 at 10:26 PM · [top] #256 There is nothing within the text to suggest that Phoebe was the leader of a house church. Yes, she was (as a widow) the mater familias of her household; she was a business owner she was wealthy and she had a home large enough to both offer hospitality and serve as a gathering place for the Church. But on what Scriptural basis do you say that she had a huge say in who led the church that met in her house? If it is because she is wealthy, how well would that gel with commands (such as that in James) to show no partiality within the Church to those who are wealthy? Yes, it was an accusation mixed with a question. Your comment requires a huge leap from what Scripture actually says about Phoebe to what you (and many feminist theologians) seem to want it to say. [257] Posted by Fr. David McElrea (formerly farstrider+) on 11-25-2008 at 10:49 PM · [top] I think Scripture suggests a connection between priesthood and Eucharist. In Genesis 14:18 we read And Melchizadek king of Salem brought out bread and wine; he was priest of God Most High… Psalm 110:4 connects this to the Messiah: The LORD has sworn and will not change his mind, “You are a priest for ever after the order of Melchizedek.” Hebrews 7:3-5 connects the Melchizedek incident to Jesus, noting that: [Melchizedek] is without father or mother or genealogy, and has neither beginning of days nor end of life, but resembling the Son of God he continues a priest for ever. And finally, we have the institution of the Eucharist itself, in which, reminiscent of Melchizedek, the Lord utilizes bread and wine, and adminishes the apostles to “Do this in remembrance of me.” It seems to me that the Melchizedech account in Genesis finds its fulfillment in both the institution of the Eucharist and in its continued celebration througout history. And, according to Psalm 110 and Hebrews, Melchizedech’s role as priest is not merely incidental. [258] Posted by slcath on 11-26-2008 at 01:09 AM · [top] There is nothing within the text to suggest that Phoebe was the leader of a house church. There is. Here’s the NIV text: 1I commend to you our sister Phoebe, a servant[footnote: or deacon] of the church in Cenchrea. 2I ask you to receive her in the Lord in a way worthy of the saints and to give her any help she may need from you, for she has been a great help to many people, including me. And the CEV: 1I have good things to say about Phoebe, who is a leader in the church at Cenchreae. 2Welcome her in a way that is proper for someone who has faith in the Lord and is one of God’s own people. Help her in any way you can. After all, she has proved to be a respected leader for many others, including me. When you were wealthy in the Greek world, you were expected to become a benefactor or patron of the community, even to the point of sponsoring public works. Furthermore, you were expected to host visitors. All this required management expertise, and Paul respected this to the point that he made her an envoy to a very significant community. Why didn’t he choose a man for such an important mission? Paul looked to wealthy people for hospitality, for their management acumen, for their natural leadership talents. Wealth was a secondary consideration for picking leaders, but it was an indicator of talent, and such people would have naturally risen to leadership. Furthermore, Paul frequently sought hospitality and patronage from such people. Acts has a number of examples of this. People who know me will know that I am far from being a feminist, that I am skeptical about WO, and far from wealthy. But the sociological and linguistic facts underlying the passage lead me to my conclusion. Your mileage may vary, of course. [259] Posted by Siangombe on 11-26-2008 at 09:49 AM · [top] ask you to receive her in the Lord in a way worthy of the saints and to give her any help she may need from you, for she has been a great help to many people, including me. And only deacons are servants of the Lord, lead in the church and help other people? [260] Posted by oscewicee on 11-26-2008 at 09:53 AM · [top] #259, Siangombe. Sorry if I was a bit sharp, but I have to say I still don’t agree with the final conclusions that you’ve drawn from the above passage. Everything you’ve said about the social context is correct… her being a Patron (even Paul’s patron) says nothing about her role in the Church. About the CEV (which translation I have suddenly lost a great deal of respect for) quotation above… here’s the passage in its original. 1συνιστημι δε υμιν φοιβην την αδελφην ημων ουσαν [και] διακονον της εκκλησιας της εν κεγχρεαις 2ινα προσδεξησθε αυτην εν κυριω αξιως των αγιων και παραστητε αυτη εν ω αν υμων χρηζη πραγματι και γαρ αυτη προστατις πολλων εγενηθη και εμου αυτου I can understand how one might argue from the language of verse 1 that she was a deacon. Not sure I agree, but the Greek could be translated as either “servant” or “deacon”. In verse 2 we have the word “προστατις,” which can be translated as “patron”. Paul’s main point is that Phoebe is well-connected and she is wealthy, but she is also truly humble (and so an example to the Roman elite). They are to receive her as generously as she has received Paul and others. This says nothing
about her being in church leadership. Note as well that the CEV translation of this passage has chosen to go well beyond the actual meaning of this passage… I wouldn’t base my understanding on it if I were you.
No, that is not quite true. Article XXXVI prescribes that one should be ordained according to the ordinal. The Church in Australia has changed that ordinal slightly, in a way that is in no means repugnant to Scripture. [301] Posted by David Ould on 12-1-2008 at 07:02 AM · [top] Again, let me repeat what is already stated. At my ordination I was permitted. That is now the legal position of the Anglican Church of Australia, which the Sydney Synod has now recognised and affirmed. If this is true, you seem to be saying that I handed you complete victory with my last post. That’s annoying. Though having reread your legal objections’ above, I’m not convinced that you were so ordained; although not having read the service I can’t be sure. Partly because I don’t like this distinction between legal and theological distinction. Mostly because the reasoning presented seems faulty. The Church of England has always (or at least Hooker), rightly or wrongly, said that even laymen and women can baptise, though only in emergency situations, so there has always been a distinction in our church between presiding at baptism and presiding the Eucharist. The document linked to in your initial post above seems to assume that there is none, and what applies to baptism also applies to the Eucharist; without any discussion that I noticed to establish this point. I don’t see that it follows, and points 20-22 aren’t convincing, more an argument from silence than anything else. And if there is a link between presiding at baptism and the Eucharist, it is just as much an argument that only presbyters should baptise as deacons allowed to preside at the Eucharist. Your link above notes three changes to the ordinal; in two cases the phrasing “assist the priest” is retained from the 1662 ordinal, which suggests that you can assist, but not administer (or preside); these changes do not support your case, because nothing essential has been changed. Most significantly, the authorisations adopt this wording. The third change troubles me, and might support your conclusion: Will you take your part in reading the holy scriptures in the church, in teaching the doctrine of Christ, and in administering the sacraments?’ There is no mention of assisting here (though your part’ might be seen to limit the scope of `administering the sacraments.’). But again, you also have to demonstrate that the National church was correct when making this change. I would also feel more comfortable it if it were made explicit in the authorisations, as it is in the case of the ordination of the priest. [302] Posted by Boring Bloke on 12-1-2008 at 08:13 AM · [top] Lay - Administration? Who has a valid “Holy Spirit Real Presence” in their offered up bread, cracker, wine, or grape juice? Wow, this is an interesting thread. Folks passionately believe and defend their positions. I knew a man, who went away to study to be a RC priest. One of his old friends from years earlier, an orthodox Episcopal Priest saw him and told him something like “ Looking forward to your ordination, and our being brothers (brother priests)” The RC’s response was something like “You and I will never be brothers!”. So, here you have once again another hurtful claim that another Christian’s ministry is totally invalid, useless, and probably leading the sheep to hell. So, some RC’s and Orthodox’s have used it from time to time on each other over the centuries. Some male Christian Priests have used it on female Christian Priests and proclaimed that as being a salvation issue. Some Baptists have said that if you are not baptized by immersion, then you are going to hell. Some evangelicals over the years have made similar claims about the RC’s. Some high Anglo-Catholic Episcopal/Anglican/Continuing Priests will not allow one of their own Deacons to administer pre - consecrated bread/wine to the sheep if the Priest is not present. So, are the sheep not to be fed? Some church leaders are “out of communion” with others due to obviously clearly defined Biblical sin issues and that is understandable. The clearly defined Holy Scriptural truths are not to be compromised. We are called to spiritual purity and not to be part of this world’s carnal spirituality. Boundaries must be set up to protect the pure from the evil. But when the issue is a style issue, that is not clearly prohibited or warned against in the Bible, then I still celebrate seeing the name of Jesus Christ lifted up even if it is done in a different style than my personal prideful preferences. If you support a Priest only administration for the bread and the wine, Are you saying that any Priestly duty done by a non-priest ministry is invalid? Are you saying that Salvation experiences, Marriages, Baptisms, and Lord’s Supper ministries performed in another’s Christian Church are invalid because the minister does not meet “your” definition of being a valid “priest” in whatever denomination / province you happen to belong to this year? Where does Biblical / Holy Spirit discernment become second place to my own human spiritual pride? Never I pray! My job description does not include being God and making salvation determinations on other human beings. This, have I pondered, for about 37 years as an Anglican Christian and about 51 years as a Christian total. In my humble opinion, I think Dumb Sheep #90 nailed it (excluding the plague comment) with his posting: (If you have to burn me at the stake with him, then have at it) ... 1) After witnessing Anglican highjinks for more than 30 years, I reached a “plague on all your houses” position. I decided for myself that my understanding of the Eucharist would be: the sacrament is effected entirely by God the Holy Spirit. No man (or woman) has any inherent or delegated spiritual power to effect it, ordination notwithstanding. 2)Ordination confers authority to celebrate the Eucharist within the jurisdiction of the ordaining authority. It is a matter of permission or authorization, not of charism. 3)This point of view does not exclude lay-celebration, as distinct from lay administration of the Sacrament to communicants. Lay celebration (presidency) is a matter of consent by Authority and the congregation being served. 4)None of this is very Anglican, or Catholic, or Eastern. It is basically a Protestant view which regards the grace of the Sacrament as given by God and the Presider merely ministers it to the people and himself. They are all receivers, the Lord is the only giver. 5) After seeing the shenanigans of too many in Holy Orders, I have come to doubt that there is anything such as a charism of Orders. I see it as a matter of church order and administration, the Church human. Burn me at the stake if you must, but I will remain always: Dumb Sheep. [303] Posted by Truthseeker on 12-1-2008 at 09:57 AM · [top] Again, no one has answered these questions in re: Councils and Tradition. The first question was asked by Antique earlier on with regard to the Jerusalem Declaration which says: “We uphold the four Ecumenical Councils and the three historic Creeds as expressing the rule of faith of the one holy catholic and apostolic Church.” The First of the great Ecumenical Councils (at Nicea) states (again): “It has come to the attention of this holy and great synod that in some places and cities deacons give communion to presbyters, although neither canon nor custom allows this, namely that those who have no authority to offer should give the body of Christ to those who do offer. Moreover it has become known that some of the deacons now receive the eucharist even before the bishops. All these practices must be suppressed. Deacons must remain within their own limits, knowing that they are the ministers of the bishop and subordinate to the presbyters. Let them receive the eucharist according to their order after the presbyters from the hands of the bishop or the presbyter. Nor shall permission be given for the deacons to sit among the presbyters, for such an arrangement is contrary to the canon and to rank. If anyone refuses to comply even after these decrees, he is to be suspended from the diaconate.” In signing the Jerusalem Declaration Sydney agreed to abide by the ruling of this Council for the sake of Anglican unity. Why is this acceptable? If TEC and the ACoC end up signing the anticipated Covenant (as some fear they will) all the while intending to do what they want, will Sydney have any moral authority to challenge them? The second question is to do with Tradition. Scripture and Tradition have constantly been played off against one another in this thread, yet we only know what books belong in the canon because Tradition tells us which books the Church recognized as Scripture. How can you reject the Great Tradition while, at the same time, appealing to those books which that Tradition has placed in your hands? [304] Posted by Fr. David McElrea (formerly farstrider+) on 12-1-2008 at 12:57 PM · [top] Scripture and Tradition have constantly been played off against one another in this thread, yet we only know what books belong in the canon because Tradition tells us which books the Church recognized as Scripture. How can you reject the Great Tradition while, at the same time, appealing to those books which that Tradition has placed in your hands? I don’t think this “little” detail can be hammered enough. [305] Posted by oscewicee on 12-1-2008 at 01:31 PM · [top] It seems to me that the good purpose in arguing against what has been construed here as the position of the Diocese of Sydney is precisely for the hope of maintaining communion with Sydney or perhaps maintaining the hope of growing into it. If the Diocese of Sydney continues in its path of schism, it separates itself yet further from the one, holy, catholic and apostolic church and the hope of restoration grows yet dimmer while in this world. Hope for restoration to the churches who gave birth to Anglicanism is all but dead forever. Sydney’s hope for restoration to a meaningful and real communion with the Anglican Communion is fading. It hardly matters if TEC has argued strenuously for what it desires contrary to all Christians in all times except their own. Likewise, it hardly matters that Sydney (apparently) has been arguing its case for twenty years. For about thirty years, TEC has likewise demanded its right to go its separate way and has moved from schism to apostasy, leaving stranded pockets of believers. We have a pretty clear example for Sydney in the undoing of TEC. Do your own thing apart from all Christians throughout time except in your pocket of humanity for two decades out of two millenium and you go alone. I suppose the next thing down the road will be the necessity of declaring Sydney a mission territory and setting up a parallel province that excludes David Ould who fails to see that the Church AND her Canon is something in particular. As to the fear that Sydney’s departure will cause the Anglican Communion to founder, it is God that maintains the Church. If this were not so, the Church would long ago have ceased to continue in time. It may be that the Anglican Communion will founder but the Church will not. But this continuing scatter pattern is not necessary. Even now, Sydney can choose to simply harken to the voices calling them back into unity. At some point, fellow Anglicans must grant them their status as adults and if they stop coming to church, so be it. What Anglicanism cannot do, as TEC has tried, is to declare that “the world” is the same as the Church. If you withdraw from eucharistic fellowship with the Church, you simply don’t realize Church when you gather…or perhaps you have a dim remaining picture of eucharistic unity such that the medicine lacks the strength to heal and innoculates against the metanoia necessary to accept Grace and turn to follow His Way apart from our way. Sure, God will be with you as He is with all peoples including those who worship Kali or their ancestors or nature. This adulteration of the faith has happened and is happening with TEC. Don’t think that whatever one might do is God’s will. That way lies spiritual delusion, self-worship and death.The three-fold orders have been given for the building up of the Church. The differing orders have evolved according to the life of the Holy Spirit in the Church for so building up and naming the differing gifts of the laity according to what Christ has shown us. When deaconal (servant) ministry becomes presidency, it diminishes that which is highest and best in the iconic teaching of the diaconate and instead merges into the icon of priesthood. If you want to be all things to all people, be a layman or an apostle. If you want to redefine the Church, go and start your own. A purely functional understanding of the Church will inevitably begin to follow these reductions. Throw out the bread and wine and substitute something more handy ... a soup kitchen for the poor ... and pretty soon, you have TEC which no longer serves the Great Commission but is morphing into a social service/social justice advocacy group ... on the world’s terms. [306] Posted by monologistos on 12-1-2008 at 01:48 PM · [top] To put it another way, the same authority upon which the canonizing of Scripture stands, has given us the three-fold order of ministry. If you deny the latter, you undercut the former. [307] Posted by monologistos on 12-1-2008 at 01:53 PM · [top] It looks like I deleted a part of the first question in #304 before I posted it… sorry about that. It should read: In signing the Jerusalem Declaration Sydney agreed to abide by the ruling of this Council for the sake of Anglican unity. Yet now it is breaking faith with its co-signers by passing resolutions which abrogate its commitment to uphold both the Jerusalem Declaration and the Council of Nicea. Why is this acceptable? The restored text is in italics. [308] Posted by Fr. David McElrea (formerly farstrider+) on 12-1-2008 at 02:02 PM · [top] Monologistos, I am in complete agreement with #307. In re: #306, I am not sure Sydeny runs the risk of becoming like TEC in terms of liberalism (if I understand you correctly); I see them as moving more towards a Brethren (perhaps) or similar non-conformist ecclesiology—conservative and devout, but not very Anglican. [309] Posted by Fr. David McElrea (formerly farstrider+) on 12-1-2008 at 02:09 PM · [top] #304 Amen on both points! [310] Posted by evan miller on 12-1-2008 at 02:35 PM · [top] How different from the Southern Baptist Convention would the new rules make the Diocese of Sydney? [311] Posted by Bo on 12-1-2008 at 03:04 PM · [top] Way to go Sydney! [312] Posted by Wright Wall on 12-3-2008 at 09:36 AM · [top] The Free Church of England has always (since its inception) allowed deacons to preside at the Lord’s Supper if the Bishops gives his permission and there is no presbyter. In the Evangelical Connexion of the FCE we remain faithful to that, feeling that it is better that individuals should be able to celebrate the memorial of the Last Supper than that some man-made law should hold sway. And, what is a ‘lay’ person? What is a bona fide ‘presider’? The Church of Rome would say many who do preside but are not of ‘their ilk’ are not fit to do so, etcetera. [313] Posted by Luthergibt on 12-29-2008 at 12:25 PM · [top] #313 Fine and good, if all it is is a memorial, but I think most of us believe it to be something rather more - a great deal more, actually. [314] Posted by evan miller on 12-29-2008 at 12:33 PM · [top] Jesus tells us in His own words that it is a memorial, so I’ll go with Him if you don’t mind. [315] Posted by Luthergibt on 12-30-2008 at 04:55 AM · [top] Bishop, A Memorial it is, but a memorial meal with deadly consequences isn’t just a remembrance supper. Christians get sick and die when they partake unworthily. Is it meet and proper to give administration of such a meal to those not ordained to that service? [316] Posted by Bo on 12-30-2008 at 05:25 AM · [top] #315 He also tells us in His own words that, “This is My Body.” It is both a partaking of Christ’s real body and blood, in a manner that is frankly a holy mystery, AND a memorial. Jesus said it is both. [317] Posted by evan miller on 12-30-2008 at 08:08 AM · [top] Bo, as the Prayer Book makes quite clear (quoting from Paul) it is up to the individual receiving it to receive worthily, not up to the minister to have control over that matter - we cannot be judge and jury over fitness to partake in the bread and wine. Evan, as the Prayer Book points out we receive Christ ‘in faith’, and this is not unconnected with Bo’s point - that is, if we have faith then the remembrance feeds our faith, if we do not then it condemns. [318] Posted by Luthergibt on 12-30-2008 at 08:31 AM · [top] Sorry, Bishop, but we’ll just have to disagree. Participating in a memorial without faith, can’t harm one. Recieving the body and blood of our Lord unworthily, however, condemns. [319] Posted by evan miller on 12-30-2008 at 08:38 AM · [top] Bishop, If we warn someone and then continue in sin, we are free of their blood. If we see them in error and do not warn them, they die for their error, and the their blood is on own hands. The fact that the receiver should know enough to reverence the supper is not enough to remove the responsibility for presenting it. this is not a responsibility that can be passed off by a ‘he should have known’ dodge. St. Paul’s letter wasn’t to the faithless, it was to the faithful, some of whom were sick, and some who slept because they ate unworthily. It ain’t the lost souls whose bodies die from eating unworthily. The care of the faithful (including warning them not to partake) is not something one gives lightly. [320] Posted by Bo on 12-30-2008 at 09:03 AM · [top] Those who use the Prayer Book Lord’s Supper faithfully, including the warning passage, and who exercise pastoral sensitivity outside the Lord’s Supper service itself (challenging and encouraging Christians to live in a worthy manner), cannot be held responsible for those who continue to partake of the bread and wine. But what am I to do when an individual whom I have never met before and whose life and lifestyle I do not know presents themselves at the table - am I guilty? It reminds me of the comment from Spurgeon - ‘If you truly knew the state of my heart you wouldn’t sit here listening to me, and if I knew the state of yours I wouldn’t be preaching to you.’ Following your dictum, if I understand you correctly, I would be loath to share communion with anyone - “for all are sinners and have fallen short of the glory of God” - and I would be judged for that? [321] Posted by Luthergibt on 12-30-2008 at 09:16 AM · [top] I haven’t done an in depth study of the developments of doctrine that occur at the Reformation within Anglicanism. What I would note is that the Church in England was Roman Catholic. The theology of the Church in England was Roman Catholic. During the Reformation, a new theology was forged. Apparently, some believe that they are capable of doing so apart from the historic Church of the first millenium. The early church, prior to the selection an authorization by the Church of the body of the Canon, were not simply adrift until the magical moment when “Holy Scripture” comes to be. The worshipping Church existed and flourished and this is the immediate source of Holy Scripture though the ultimate source is of course God. I’m sure that the writers here are holy men and women ... it would be wrong of me to question either their intent or their sanctification. I will presume that none here knew the apostles personally. If not, I would suggest that those who did might have a better notion of what Scripture means than those of us who literally are unable to read Holy Scripture without using the TULIP lens or whatever. Fact is, Holy Scripture is not dependent upon Calvinists or Lutherans or Anglicans even for its meaning. The meaning of Holy Scripture is not a Rorshak ink blot test whereby we apply “magic” or “psychology” to get out what God wants. That simply gets at what we want.As an Eastern Orthodox, I listen to the various discussions here that seem to assume that the early church, which, as the immediate source and authorizer of Holy Scripture, is perhaps clueless compared to ourselves when defining what Jesus said and I just have to shake my head. Certainly, Rome went off the deep end following the logic (and errors) of Augustine’s notion of Original Sin ... which lead logically to the very Marian dogmas that Protestantism universally rejects as not necessary to salvation and thus not appropriately dogma (such as the Immaculate Conception of Mary and the Assumption of Mary) ... yet I don’t find Reformed churches rejecting Augustine’s notions of Original Sin that lead to the same. The rest of the historical churchs do not jump on Augustine’s bandwagon on this ... but the western church takes a sharp turn here and Protestantism is mired in the same legalistic formulations of sin and redemption that beset Rome. Granted, for those who like to believe they *CAN* lay everything out nice and logically, whether Thomists or “ultra-conservatives”, and make lists of fundamentals that must be believed for salvation, perhaps this appeals to a particular personality type. I don’t agree that matching theology to personality type is helpful for salvation. The Protestant enterprise of defining which fundamentals are necessary and then battling over the definitions of the same apparently continues in Anglicanism today and like a Tower of Babel that keeps on giving, the ongoing schism has seeded the world with sects of Christianity who have self-defined vital differences that prevent them from true koinonia.I know quite a few Anglicans that have joined Eastern Orthodox parishes and many are flourishing. But the gig is up. All your useless value to the great enterprise of Protestantism becomes irrelevant. All your kibbitzing needs to stop so that you can get along with learning to be quiet and honor the Holy Spirit’s work of sanctification. In fact, a great deal of your scholarship is pointless because in Orthodoxy, nobody really cares about TULIP or the Pope or YOUR interpretation of Scripture except insofar as they care about you. Of course, we all come with our expectations. Most of us come with our insistance that the Church ought to resemble something we have known in our life but lost. Not all congregations are healthy places where edification happens. Having the fullness of the Christian faith does not mean we know how to appreciate that ... but appreciation begins with gratitude and gratitude is expressed by thanksgiving in earnest prayer with God. If we spent a bit more time going into our rooms, closing the door, and giving thanks to God and most important *listening* to Him, we would have less time for the politics that goes by the name of theology in so many places. [322] Posted by monologistos on 12-30-2008 at 09:25 AM · [top] monologistos,I would like to know more about the Orthodox view that precedes Augustinian “original sin.” This thread is probably not the place for it. Perhaps you would send me a private message? [323] Posted by oscewicee on 12-30-2008 at 09:35 AM · [top] Bishop Said Those who use the Prayer Book Lord’s Supper faithfully, including the warning passage, and who exercise pastoral sensitivity outside the Lord’s Supper service itself (challenging and encouraging Christians to live in a worthy manner), cannot be held responsible for those who continue to partake of the bread and wine. , and I agree with him! He then asks But what am I to do when an individual whom I have never met before and whose life and lifestyle I do not know presents themselves at the table - am I guilty? . And it is a very good question. One the presenter would need to know how to answer (such that resonated with the Scripture, and the safety of the souls involved). This brings the point about being ordained to this ministry into focus. If the path to ordination is followed, discernment and training are both used to make sure the one presiding can answer well and faithfully the question. That is part of what should distinguish the difference in the training and spirit of a deacon from a priest. Deacons aren’t supposed to find themselves in that circumstance. (If you didn’t take the time to find out before you administered the poison, I think you’d be guilty) We are all sinners, but not all are unworthy of the Lord’s Supper (or we all would sleep). If you truly think that being a sinner would keep one from the Lord’s Supper, then you should by all means avoid it. Mind, I’m not saying that the meal is ‘invalid’ if presented by laymen. I have done so in my own home. I am saying it is unwise to put such a responsibility on those not specifically called and ordained to the role in public, where they have to face the very hard question you asked. If Sydney needs more priests for the service of the Lord’s Supper, they should license them (God will provide for our needs), not impose this dangerous duty on those who aren’t ordained (properly prepared and bathed in prayer and anointed) to it. It also gives offense to those who hold a more ‘mystery’ view, is not commanded of scripture, and seems even more ‘congregational’ than the Baptist churches. Why do all that when those who qualify for deacon willing to risk it would also qualify as priest? [324] Posted by Bo on 12-30-2008 at 09:46 AM · [top] #323, I would like to know more about the Orthodox view that precedes Augustinian “original sin.” Precedes and follows. Augustine is not particularly *central* with us. We honor the saints but do not take the entire corpus of their teachings as canon, holding that even the Fathers can and do err from time to time. Very shortly, Augustine’s theology of Original Sin is based on a mistranslation made by Jerome (eph ho versus in quo). We all are affected by the consequences of the Fall. However, we are not personally culpable for it ... thus infants are not damned if not baptized. This may look Arminian to TULIP people but we do not understand it so. God’s freedom we place higher than the determinism insisted by some. But this thread runs throughout Protestantism’s understanding of salvation and atonement forcing the development of endless orbital epicycles to buttress the notion of the perfect circle of “justification by faith alone”. I wonder what they will do with it with Rome beginning to recognize the problem and doing away with the “pastoral” fudge factor of Limbo. Over-explanations tend, like the concept of Karma, to define what God is capable of according to the measure of man’s understanding. I grant you the liberals in TEC may misuse such reasoning for their libertine attempts to declare the church an antinomian affair but misuse is not the sole territory of any party. [325] Posted by monologistos on 12-30-2008 at 10:08 AM · [top] As a thought experiment, what if Augustine had never lived ... would the Church be maimed? What if Protestantism had never happened? Would the Church have ceased to be? I often marvel at those Episcopalians who claim they would never belong to a church that doesn’t have “open communion” and yet it wasn’t “open” until a few short years ago. If we would only belong to a church that has achieved acceptability to us in the past thirty years perhaps, or 500 years even, does this make our modern choice a “New Age” church? I don’t mean these as fighting words but it is an interesting experiement. [326] Posted by monologistos on 12-30-2008 at 10:16 AM · [top] Thank you, monologistos. We all are affected by the consequences of the Fall. However, we are not personally culpable for it ... thus infants are not damned if not baptized. This may look Arminian to TULIP people but we do not understand it so. God’s freedom we place higher than the determinism insisted by some. But this thread runs throughout Protestantism’s understanding of salvation and atonement forcing the development of endless orbital epicycles to buttress the notion of the perfect circle of “justification by faith alone”. How does the Orthodox church view justification? I confess to not knowing what TULIP stands for. Your point about when does innovation stop being “new” (500 years, 30, yesterday?) is a good one. Bo, you have the simple answer in #324, and I wonder why Sydney does not choose it? If Sydney needs more priests for the service of the Lord’s Supper, they should license them [327] Posted by oscewicee on 12-30-2008 at 10:28 AM · [top] Bo, the Church has often been given priests who were unready for the job, who were theologically untrained. “Sometimes” they fall short of what God desires for each but we trust that if the Church authorizes that person to act on it’s behalf according to Christ’s own words, what we ask in His name is done for us. Truly, it would be ludicrous to assume that it is a three year seminary course that makes for “valid” Eucharists. Sydney is under no constraints but those of their own making. They can ordain men to the priesthood for a time who are perhaps not well trained ... as an acceptable exception. I note that much of priestly formation happens *after* ordination. I think I may have to disagree with the thrust of Bishop’s comments regarding responsibility for communicants. This is an important consideration in raising men up for positions of responsibility. We have an obligation to the priests also in this for the priest’s salvation may be lost if he through refusal to accept responsibility brings about the damnation of a member of his flock. This does not make the priest *fully* responsible of course ... it makes him responsible for what he has been given. If he marries a couple who have no business marrying and the marriage fails, he has a measure of responsibility. If priests don’t like this, they ought not to become priests…or bishops. It is an aspect of fatherhood and of headship. So also was Eli responsible for not having reigned in his sons. Though he performed the priestly role of introducing Samuel to the Lord, a good thing, this did not undo his other failure. It would be wrong of me to speculate on Eli’s ultimate salvation in heaven but he died because his irresponsibility for his children was reckoned as sin before God. [328] Posted by monologistos on 12-30-2008 at 10:34 AM · [top] Salvation is more a matter of our relationship with God in Christ and less about whether we can determine by some definition and calculation whether we are “saved”. Justification *tends* to be a legal calculation. Legal language certainly has a place in Scripture and is loved by those who believe they are justified while retaining grave doubts about their neighbor. I would say that I have been saved, that I am being saved, and that I hope to be saved. Keeping those things in tension can be difficult. There are those whose personality does not lend itself to ambiguity and so resort to manipulation (magic) or calculation (bargaining) but salvation depends on a relationship with God that is summed up by the first and greatest commandment and the second which is like unto it. We can safely assume that God is there for us and that He loves us. We cannot assume upon that relationship without losing the gift of humility. The process of perfection (sanctification) by the Holy Spirit requires our cooperation in response to God’s initiative, as mouse poor and tiny as that may be next to Grace. This really isn’t anything strange or foreign to any of us here but we often get caught up defining ourselves in reaction to error such that we end up overstating the case to the point that we are equally offbase. That we have a very logical formulation and many clever definitions of Justification means very little as justification is not an IQ test. If it were, then the Kingdom of Heaven would hardly be catholic ... being only for scribes and lawyers who like logical systems. We should not suppose that God’s Truth lies along a simple single dimension such that at one polar end, you have, for instance, communism and at the other end fascism and that sums these up as opposites. Our calculation of what it means to be a middle needs a lot more refinement which of course complicates things until perhaps we see the model is not that helpful…it is perfectly possible to achieve simplemindedness with great complexity and thus become publishable ... but that is a different enterprise. But with God, we cannot adequately force our relationship with Him into such schemes. I would sum up by saying that it is not helpful to view salvation as entirely linear even though that may be one aspect of reality ... that at one end of the line is damnation, that we move like a vector as a point on that line towards or away from God at the other end ... and that there is some point on the line that marks “justification” and if we are past that, we are justified. Repentance is a struggle which continues until the moment we die. And no, we are not saved BY struggle but without struggle and without suffering, we cannot be Christians in this world. My advice would be to pay less attention to justification, especially various doctrines of Justification, and more to praise and thanksgiving to the living God, trusting in Him. The publican who prayed, “Have mercy on me a sinner” left his prayer justified. Should we make acknowledgement of sin and also humility the measure of Justification? It’s a good start - prayer, that is. What is lacking for so many, is that they do this on their own ... that they no longer have corporate disciplines or even corporate worship. [329] Posted by monologistos on 12-30-2008 at 11:42 AM · [top] monologistos, Thanks for your #329. One of the most sensible comments on this or any other thread I’ve read in quite a while. [330] Posted by evan miller on 12-30-2008 at 12:06 PM · [top] but salvation depends on a relationship with God that is summed up by the first and greatest commandment and the second which is like unto it. We can safely assume that God is there for us and that He loves us. We cannot assume upon that relationship without losing the gift of humility. The process of perfection (sanctification) by the Holy Spirit requires our cooperation in response to God’s initiative, as mouse poor and tiny as that may be next to Grace. monologistos, thank you so much for this post. Especially for the above and this: My advice would be to pay less attention to justification, especially various doctrines of Justification, and more to praise and thanksgiving to the living God, trusting in Him. The publican who prayed, “Have mercy on me a sinner” left his prayer justified. [331] Posted by oscewicee on 12-30-2008 at 12:22 PM · [top] Hello monologistos, I agree with many of your statements but I believe that it is important to note that according to Sacred Scripture, we should never pay “less attention” to our justification, for our justification is the central cause for our praise and thanksgiving to the Living God. (And yes, I mean our “forensic” justification in the purging of all our guilt (both in omission and commission) before the Throne of God through the Blood of Christ—so that we stand (despite the continual great imperfections of our heart in this life) perfectly righteous or “whiter than snow” before our Heavenly Father in Christ Jesus (with Whom we are “clothed” before the Father), as both the Scriptures and Church Fathers teach). The knowledge that we are washed from all stain of sin and made whiter than snow before our Heavenly Father through the Blood of Christ in our Baptism, and that we are continually renewed in this perfect washing through a living faith, although we are still imperfect and sinful in all our works during this life, is something we should always keep before our eyes (that we may always be humble as the Publican, and always recognizing and rejoicing in the greatness of the debt which Christ forgives in our life—as the man who was forgiven the larger debt in Christ’s Parable and therefore had greater love towards His Lord). And although we are being transformed more and more into the image of our Lord in this life—yet sin is ever present with us—For we always stand, according to our works (in thought, word, and deed) condemned as the Publican before the Awesome Holiness of our God (Whose Holy Law requires the absolute sinlessness of perfect love toward God and neighbor at every moment) and therefore we must rely wholly on the Perfect righteousness of our Lord Jesus Christ’s Incarnate Life in this world—wherein He perfectly fulfilled the Law (both in His life and death) for our full and complete justification before Almighty God. The Heavenly Father declared Christ fully justified in resurrecting Him from the dead—and Christ was justified on the basis of His sinless or perfectly righteous life and death. And through our spiritual union with Christ we are likewise declared fully justified with Christ in His resurrection by the Heavenly Father—not on the basis of any of our imperfect good works but on the basis of Christ’s perfect life and obedience alone (for, again, the Heavenly Father declared Christ (and we in Him) justified in raising Him from the dead—not on the basis of any righteousness we have done but on the basis of the righteousness of our Incarnate Lord and Savior life in this world). St. Bernard of Clairvaux stated these points well: What can all our righteousness be before God? Shall it not, according to the prophet, be viewed as “a filthy rag;” and if it is strictly judged, shall not all our righteousness turn out to be mere unrighteousness and deficiency? What, then, shall it be concerning our sins, when not even our righteousness can answer for itself? Wherefore, exclaiming vehemently with the Prophet, “Enter not into judgment with Thy servant, O Lord!” let us flee, with all humility, to Mercy, which alone can save our souls. . . . Whosoever, feeling compunction for his sins, hungers and thirsts after righteousness, let him believe in Thee, who “justifiest the ungodly;” and thus, being justified by faith alone, he shall have peace with God. . . . Thy Passion is the last refuge, the alone remedy. When wisdom fails, when righteousness is insufficient, when the merits of holiness succumb, it succours us. For who, either from his own wisdom, or from his own righteousness, or from his own holiness, shall presume on a sufficiency for salvation?’ Blessings in Christ, William Scott [332] Posted by William on 12-31-2008 at 01:15 AM · [top] Just noticed a glaring typo (left out the ‘s on Savior): “...(for, again, the Heavenly Father declared Christ (and we in Him) justified in raising Him from the dead—not on the basis of any righteousness we have done but on the basis of the righteousness of our Incarnate Lord and Savior’s life in this world).” [333] Posted by William on 12-31-2008 at 01:31 AM · [top] I should note regarding Baptism in the above post that I am not intending to contradict what St. Aquinas taught regarding the Baptism of desire—namely that an unbaptized adult through a living faith or the “desire of Baptism” (a living faith always containing, according to St. Aquinas, either an explicit or implicit desire of Baptism) begins to partake in the blessed washing of Baptism even before receiving the Sacramental consummation of that washing (which vital “consummation” occurs through the inward washing with the Spirit and the Blood of Christ which occurs when the worthy recepient enters the Sacramental waters of Baptism). Blessings in Christ, William Scott [334] Posted by William on 12-31-2008 at 02:06 AM · [top] Another quick correction—this time for misspelling, etc: “...(which vital “consummation” occurs through the inward washing with the Spirit and the Blood of Christ which the worthy recipient receives when he enters the Sacramental waters of Baptism).” [335] Posted by William on 12-31-2008 at 02:16 AM · [top] David, Actions have consequences, everywhere. If Sydney does this,. or carries this through without consultation with GAFCON Partners and the wider Communion, then it makes GAFCON as complicit as TEC in violation of both Scripture and tradition. If therefore GAFCON (Sydney)becomes a bedfellow with TEC, I am afraid I must withdraw from FCA and GAFCON, which displeases me immensely, simply because pig headed Sydney Synod wanted their way without reference to brothers and sisters elsewhere. ACTIONS HAVE CONSEQUENCES indeed. Brian+ [336] Posted by Brian on 8-31-2010 at 07:57 PM · [top] If Sydney does this,. or carries this through without consultation with GAFCON Partners and the wider Communion, then it makes GAFCON as complicit as TEC in violation of both Scripture and tradition. Well hang on. Having review the thread let me make a point that was already argued earlier up. You accuse those who support diaconal administration as violating Scripture. As above, I would ask where does the Scripture actually proscribe such a course of actions? You accuse those who support diaconal administration as violating Tradition. As above, I would ask why are we bound to Tradition where it places a burden on us not actually found in Scripture? Now, as I have repeatedly conceded, I am more than happy to listen to the argument on wounding our partners feelings and, perhaps, raise the issue of the weaker brother. But the kind of strident claims being made here should, I feel, be responded too. Are these really the lines we are going to draw and break fellowship over? [337] Posted by David Ould on 8-31-2010 at 08:29 PM · [top] [336] Brian Actions have consequences, everywhere. OK, but in this case the consequences are punitive, and one wonders why punitive consequences should attach to the action. What is Sydney doing that is so terrible? It is talking about overturning tradition. So what? Do you defend tradition simply for the sake of defending it? What is the rationale behind the tradition? What do you lose by forsaking it? What do you gain by forsaking it? Why was this tradition established in the first place? This should be the ground of the argument. Instead what I see is this: Anti-Sydney: “Thou shalt not forsake tradition!” Sydney: “Why? What does a priest add that is essential?” Anti-Sydney: “You are an anti-Anglican heretic for even asking that question! [Removes shoe and pounds it on the table.] THOU SHALT NOT FORSAKE TRADITION, or thou shalt be CAST OUT!” Sydney: Where stands it written? Anti-Sydney: [Throws shoe] IT IS WRITTEN IN THE TRADITION OF THE CHURCH! This kind of argumentation is not intended to persuade. It is intended to intimidate. And the vehemence of the attempted intimidation only reveals the lack of true authority in the tradition. carl [338] Posted by carl on 8-31-2010 at 08:54 PM · [top] David, There is a two-fold problem for evangelical Anglicans in the way Sydney Synod is going about this issue: 1. The Anglican reformers (and indeed the continental reformers at the same period, such as Calvin) were clear on the essentials of church government: The celebration of Holy Communion is one of the essential functions of Presbyters (or elders/pastors/priests, whichever term you like to use). By contrast, the functions of deacons are to ASSIST the Presbyter in celebrating Holy Communion, to preach (but under the bishop’s authority), to baptise (but under the presbyter’s authority) etc. In other words, Sydney appears to be changing fundamental Anglican polity laid down since the Reformation. If you are going to change something that has been at the very foundation of Anglican church government since Thomas Cranmer, its not enough to say: “The Bible permits this”. The question is, “Why do it at all?” There are real concerns among orthodox Anglicans that Sydney is not being honest with itself, that it is in fact being suborned by the spirit of the age. It can happen to the best of us. And it is no answer to say: “Deaconesses working in all-female institutions need to be able to celebrate communion”, because the Sydney measures (now that I have looked at them) go much further than that. They permit communion to be led by a deaconess even when there are men present. 2. This leads on to the second problem: Why isn’t this just “WO by stealth”? If a deaconess can function effectively as a rector (which is where we seem to be headed), then isn’t she really just a presbyter? I am a long-time Sydney lay person, I well remember the debating tactics used by Patricia Brennan (who went to school with my Mum) Keith Mason et al during the attempts to get Sydney to adopt WO in the 1980s. Some of the arguments used by proponents of diaconal administration at recent Synods sound very similar, in tone and content. [339] Posted by MichaelA on 8-31-2010 at 09:37 PM · [top] Mr. Ould, to the degree that the three fold order exits in Scripture, Deacons are not ones in authority. Authority is required to deny the communion. The communion is to be denied to those unrepentant. It follows to this simple mind that deacons do not biblically lead communion (except perhaps in their own household where the authority is that of husband and father?). Where is the biblical basis for a deacon to have the authority to deny communion? Without authority to deny, there is no regulation of the Lord’s Supper. Communion of the unbaptised anyone? [340] Posted by Bo on 8-31-2010 at 10:58 PM · [top] #338 I don’t think that is quite right. The sixteenth century reformation in the COE enforced (occasionally severely) all sorts of things that aren’t demanded by Scripture but were deemed to be fitting, consonant with Scripture and within the lawful jurisdiction of the authorities to decide. I think for example, of wearing vestments or making the sign of the cross at baptism. So the theological question is not tradition vs Scripture, but the right of the appropriate authority to order the church, consonant with Scripture, in whatever way seems fitting. Sydney seem to be claiming this authority for themselves and it’s not obvious to me that they have the right to do so. Doubtless the authority structures of the Communion are desperately lacking in clarity nevertheless I see the Communion as a whole as in genetic continuity with the church of a single “realm” out of which it grew. Within the “realm” or “realms” of an appropriate authority the Reformers expected and enforced uniformity of church order - both in Calvin’s Geneva and Cranmer’s England. Of course if one were to claim that the three fold ordering, rightly interpreted, is itself not consonant with Scripture, there one would depart from the mainstream COE Reformers. [341] Posted by driver8 on 9-1-2010 at 12:02 AM · [top] RE: “Are these really the lines we are going to draw and break fellowship over?” That’s been made very clear for years now—it is of sufficient seriousness that Anglicans will not be in the same organization with those who practice it. As to whether that unwillingness to be in the same organization with practitioners of lay administration is the same as “breaking fellowship” that could be debated either way. In one sense, all denominations are a “broken fellowship” in that numerous Christians have made the decision to be a part of one organization while rejecting the others. I am “in fellowship” with Baptists—but I certainly do not wish to be a Baptist or a part of the Southern Baptist Convention. So I’m not certain that Anglicans not being in the same organization together *always* has to mean “we’ve broken fellowship with one another.” RE: “Ok, but in this case the consequences are punitive, and one wonders why punitive consequences should attach to the action.” Actually, *painful* or *serious* consequences for actions are not necessarily “punitive” at all. Punitive implies the intention to punish, and I don’t think that the acknowledgement that one will not be willing to be a part of an organization whose members practice certain things unacceptable to others is “punitive.” Indeed, Brian merely points out—as so many others have—that *he himself* will experience the consequences by having to depart the organization that has a diocese enact lay administration. RE: “What is Sydney doing that is so terrible?” Of course, you already know the answer to this question, and repeating it over and over doesn’t make it any more compelling or relevant. What Sydney is doing is “so terrible” not to Carl—who is not an Anglican—but to many many Anglicans within the Anglican Communion. There is no need to explain why it is so terrible, since Anglicans and Carl don’t share the same foundational values or principles in a number of areas, and so no explanation will suffice. Obviously, we’ve learned the same thing for those pushing this practice and those resisting it. No explanation will suffice for either side, since the two groups’ conception of ordination, the clergy, the sacraments, etc, etc, are intrinsically contradictory in many aspects important to both sides. RE: “This kind of argumentation is not intended to persuade.” Indeed—not only is it not intended to persuade, it’s not even an argument. Nor does it intend to be an “argument.” It merely points out what will happen—reality. RE: “It is intended to intimidate. And the vehemence of the attempted intimidation only reveals the lack of true authority in the tradition.” Spoken like a True Schori-ite. People pointing out the consequences of one diocese taking an action that others find profoundly heretical is not “intimidation”—it is factual. That allows the potential actor to make some decisions about his behavior with clear knowledge of the consequences. We know how TEC made those decisions. They were warned very clearly and all pretenses of shock or confusion simply makes them even less admirable in their character. [342] Posted by Sarah on 9-1-2010 at 12:05 AM · [top] I want to add a slight irony that brings a smile to my face about some of this. For TEC is already in full communion with a church that permits under some circumstances not diaconal but lay presidency at the eucharist: namely, the ELCA. So I think we have to take the hands thrown up in horror by the TEC progressives with a knowing smile and a big pinch of salt. Of course it’s not the TEC progressives with whom Sydney ought to be concerned but the many orthodox Anglicans who disagree profoundly that Sydney has the authority to enact any such proposal. [343] Posted by driver8 on 9-1-2010 at 12:28 AM · [top] You accuse those who support diaconal administration as violating Tradition. As above, I would ask why are we bound to Tradition where it places a burden on us not actually found in Scripture? Scripture may not be specific (although I think what inferences that can be made are against diaconal administration, e.g. the only examples in scripture we have of the breaking of bread one of the apostles presided, and we know none where a deacon or member of the laity presided), but we can be certain that the apostles and Christ himself held one view (that administration was reserved for presbyter/bishops, or that it was a matter indifferent). Do you want to risk practising something that the apostles condemned even if that condemnation is not recorded in scripture? This matter may not be necessary for salvation—obviously, since baptism, communion and the Church itself are not necessary for salvation (the thief on the cross), but that doesn’t mean that this is not an essential matter for the right ordering of the Church. The only inference we have to find the apostle’s and Christ’s commands on this matter is the tradition of the primitive church—which is both early and unanimous. Secondly all the magisterial reformers, but with Anglicanism as the clearest example, adopted the policy that where scripture is silent and there is an early and unanimous tradition, we should follow that tradition. The argument against the Romans was and remains that they had added to the polity of the Church in opposition to what was practised in the earliest days. With this, Sydney is doing the same. Even if what you are doing is permitted, it is not in accordance with the polity of the Anglican Church (just as the issues of polity where differ from ourselves may not exclude them from being Christian, but it certainly excludes them from being Anglican). Thirdly, a diocesan synod does not have the authority to overturn a matter of Church polity that originates with the apostles. Taking on a local synod this kind of authority which it does not have is one of the mistakes made by those who speak in favour of women’s ordination. Early and universal tradition matters because part of the polity of the Anglican Church and the wishes of the reformers is to follow it where it does not clearly contradict with scripture. [344] Posted by Boring Bloke on 9-1-2010 at 12:42 AM · [top] Dean Munday posts an excellent, extraordinarily well-supported and researched summation here: http://toalltheworld.blogspot.com/2010/08/what-should-we-think-of-lay-presidency.html . [345] Posted by Athanasius Returns on 9-1-2010 at 02:15 AM · [top] David, I refer you to Matt No 37 I refer you to Fastracker No 289 You make dispersions that “I accuse” X 2 nothing of the sort.. It is obvious you overlooked my first word “IF”, making it hypothetical, so please don’t make me something I’m not. I repeat, IF Sydney goes ahead with this without reference to Gafcon and the wider Communion, then they are no better than TEC and its blatant hypocricy. Brian [346] Posted by Brian on 9-1-2010 at 02:48 AM · [top] subscribe [347] Posted by merlenacushing on 9-1-2010 at 08:00 AM · [top] [342] SarahOf course, you already know the answer to this question, and repeating it over and over doesn’t make it any more compelling or relevant. Oh, I understand quite well the non-answers you are giving over and over and over again. But those answers don’t address the questions I keep posing. They serve only to avoid the issue. The irony of your post is how clearly it demonstrates the template of conversation I provided. You have misunderstood my part in this argument from the beginning. I am not advocating for or against Lay Presidency. I am attempting to push the argument away from a mindless assertion of tradition. If you have an actual case to make against Lay Presidency, then make it. Typically, that involves argument. Carl—who is not an Anglican Is David Ould an Anglican? Does he share the “same foundational values or principles” of other Anglicans? Should I go back through all the threads on SFIF and pull up those places where you have called him an Anglican? But he asks the same questions, and you won’t answer him either. So of what relevance is this statement? Or should I understand that you have indirectly charged David Ould with ‘Anti-Anglican heresy’ by pointing out that I am not an Anglican? There is no need to explain why it is so terrible, since Anglicans and Carl don’t share the same foundational values or principles in a number of areas, and so no explanation will suffice. Of course. If I disagree with a Baptist on baptism, it must be the result of differing “foundational values or principles.” Argument is therefore impossible, and reasoning together from Scripture is excluded. If I disagree with a Dispensationalist on Eschatology it must be the result of differing “foundational values or principles.” Argument is therefore impossible, and reasoning together from Scripture is excluded. If I disagree with a Lutheran on the nature of Communion, it must be the result of differing “foundational values or principles.” Argument is therefore impossible, and reasoning together from Scripture is excluded. Each collection of the Church becomes by definition its own hermetically-sealed unit incapable of communicating beyond its own presuppositions. Do we not share a common Lord? Do we not share a common faith, and a Gospel, and a common Spirit, and a common Scripture to which we are all in submission and to which we can all appeal? This is why we limited finite creatures can reason together about our disagreements - because we do share the same “foundational values or principles.” It is true that I am not an Anglican. But I am a Christian, and I do share the foundational values and principles of the Christian faith with those who run this blog. If it were not so, I would not be here. I would not have invested some portion of the last four years of my life commenting here. It is in fact beyond dispute that you, Protestant Sarah, share foundational values and principles with me far more tightly that you do with your Roman Catholic allies on this thread. And yet you blithely dismiss me as ‘non-Anglican.’ Not all disagreements are presuppositional, Sarah. People who share presuppositions can still disagree. When they disagree, they can lean upon those common presuppositions and reason together. If you do not believe these things, then I wonder why you even write on these subjects. Do you write to edify me? No, for you assert you cannot convince by argument. Do you write to teach me? No, for you assert you cannot convince by reason. Do you write to help me, or assist me, or aid me in any way? You have precluded all these things by your blanket assertion of differing “foundational values and principles.” Do you then write to proclaim judgment on those with whom you disagree? Is that the sum total of your involvement? Do you speak the truth only so that the hearer will be condemned by what he hears? What are you doing on this thread? carl [348] Posted by carl on 9-1-2010 at 08:18 AM · [top] RE: “I am attempting to push the argument away from a mindless assertion of tradition. If you have an actual case to make against Lay Presidency, then make it.” I understand that you are attempting to do that. But Anglicans don’t believe that tradition is “mindless.” I have no need to make an “actual case” against Lay Presidency—those cases have been made for years and years and years—and Sydney has made the opposite case for years and years and years. At the end of the day it comes down to . . . Sydney does not share the same theology about clergy, sacraments, tradition and much more than the rest of the Anglican Communion. The fact that you wish to sidetrack the discussion into “let’s run down the same rabbit trails again and demonstrate again to the world that “lookie, the two groups are unalterably opposed” may satisfy Carl’s idea of entertainment but in the end it’s merely the distraction that Carl seems to pursue whenever he’s actually merely angry over the consequences of difference among Christians. RE: “Argument is therefore impossible, and reasoning together from Scripture is excluded.” Argument is certainly possible. ; > ) RE: “If you do not believe these things, then I wonder why you even write on these subjects.” I adore communicating ideas with clarity and passion and I shall continue to do so. And just because I do not wish to satisfy your need for distraction by arguing with you pointlessly does not mean that I do not get to communicate. The issues would be clear even after many many many many more hundreds of hours of pointless Buddhist prayer wheel argument. The issues are 1) one rather large group of Anglicans holds at the least a lowest common denominator belief about the clergy, ordination, laity, sacraments and church tradition and 2) another much smaller group of Anglicans does not hold those beliefs but wishes to institute practices that stand as an icon of confirmation for them that there is no significant difference between the laity and the clergy and 3) those actions are not adiaphora for the first group. RE: “Do you write to edify me?” No, not at all. Though I sometimes have been privileged to edify others. RE: “Do you write to teach me?” No. Nor to persuade either. I am utterly disinterested in teaching or persuading you and consider those usually to be side benefits of writing, not the main point. RE: “Do you write to help me, or assist me, or aid me in any way?” No I do not. I would never presume to assume that I am “helping you” since I do not know you nor have you asked me to help you or assist you. Often writers write with someone in mind—and I do do that. But those people—those faces—are usually people whom I know personally so that I can write with their thoughts and needs and feelings in mind. This serves to make my writing, I hope, personal and meaningful to some—an audience out there that is kind and thankful for things I’ve written that have—happily—helped them. But certainly my writing is not personal and meaningful and helpful to all. That’s okay with me—writers aren’t for everyone. RE: “Do you then write to proclaim judgment on those with whom you disagree?” I do often write to help others see the inconsistency of certain views or assertions. It is helpful for others to be able to articulate those inconsistencies and thus navigate their way to unified, coherent arguments for themselves. Nevertheless, this thread is not about me and your frustration with my refusal to engage in your preferred mode of communication. If you have issues with me feel free to email me—although it will not, ultimately, provide you any satisfaction, I suspect, since I’ll continue communicating about these issues in a way that you do not like. [349] Posted by Sarah on 9-1-2010 at 09:34 AM · [top] Rev Mr. Ould You have rightly brought up the question of Art VI of the 39 articles and it is on this ground that I want to meet you head on. Art VI reads, “Holy Scripture containeth all things necessary to salvation: so that whatsoever is not read therein, nor may be proved thereby, is not to be required of any man, that it should be believed as an article of the Faith, or be thought requisite or necessary to salvation.” It is precisely this that seems to me to forbid, lay presidency at the Eucharist. For the scriptures tell us explicitly in 2 Thess 2:15 and by implication in other places that we are to hold to the oral teachings of the apostles. Thus if for example St. Ignatius was to say, “St John told me X” or “St John told Y who told me X” then X would have to be received as true, unless Y or St. Ignatius were shown to be liars. Further, since ours is a faith of actions not word only, James 1:22-25. The acts of the apostles observed and followed by the church fathers are thus by implication to be treated in a like manor. The witness of the undivided church (and also of the Monophisite and Arian heretics) is for the threefold ministry and the restriction of the Presidency of the Eucharist to the Priests and Bishops. Now granted this is not the same as having a passage of the scriptures that says “no lay presidency” and it is therefor not “read therein,” but it is a teaching that “may be proved thereby.” Further, I dispute that you need lay presidency because you don’t have enough priests. If your missions and parishes have both morning and evening services on the Lord’s Day, as they should, then one priest is enough to celebrate the Eucharist on Sunday once a fortnight at each of four missions. This would also allow the same priest to supervise the deacons running the four missions who after all are not being ordained priest because they are not judged yet ready to be Rectors. Further, I do not understand the reasoning that says “we won’t have assisting priests because that offends our reformed sensibilities,” but then decides to turn deacons into assisting priests by allowing them to preside at the Eucharist. How is this reasonable? Further, Sydney is breaking Catholic order, by its “prophetic” act of authorizing lay presidency. How this is different from WO or unrepentant GLBT ordination escapes me. Thus I call upon Sydney and you my brother to repent. Yours in Christ, Cuthbert Stephenson [350] Posted by CuthbertStephenson on 9-1-2010 at 11:04 AM · [top] Well, all I can say to this development is that if my parishioners, or anyone else for that matter, travelling to that diocese should ask me what they ought to do, I would tell them that having a lay person merely licensed by a bishop purport to administer Holy Communion would produce a completely invalid result, ecclesiastically. The same as any sacramental services conducted by Carolyn Tanner-Irish, who was baptized a Mormon but never subsequently baptized a Christian before her various purported ordinations. However, in Mrs Irish’s case, her sacramental ministrations are not only invalid but also null. [351] Posted by A Senior Priest on 9-1-2010 at 01:45 PM · [top] David Ould, On Stand Firm you will find people from a wide variety of backgrounds. You will indeed find some who argue from an “apostolic tradition” or “sacerdotal” background - such is the nature of the beast. Their arguments are poorly formulated and I would not expect you or anyone else in Dio. Sydney to take any notice of them. But I hope that those in Sydney who support diaconal administration will read carefully and take to heart the many admonitions by those who write from a classical Anglican reformation perspective. For example: * My post at #339, * Bo at #340, * Driver8 at #341 and #343, * Boring Bloke at #344, * Athanasius Returns at #345, * Brian at #346. Each of these members (none of whom I know, and being a Sydney-ite myself I doubt that I even share a continent with them) writes more in sorrow than anything else. The thrust of their message is that, in permitting diaconal administration Sydney is doing great damage to the fabric of true orthodoxy in the Anglican Communion, because it is departing from fundamental tenets of Anglican polity, firmly and clearly laid down by the Anglican reformers (and indeed also by the continental reformers). I hope that this message will be taken to heart by many in Sydney. If you believe that these brethren are incorrect in what they write, then by all means lets discuss it. But their concerns cannot be simply dismissed as being based on “sacerdotal” assumptions - rather, they are concerned that fundamental doctrine held by Cranmer, Bucer, Calvin et al. are being tossed in the bin by Sydney, for no clear or justifiable reason. [352] Posted by MichaelA on 9-1-2010 at 05:58 PM · [top] Carl #348 I am attempting to push the argument away from a mindless assertion of tradition. If you have an actual case to make against Lay Presidency, then make it. Typically, that involves argument. Carl, I love the fact that you are here on Stand Firm. But the above excerpt demonstrates why you cannot moderate (in the broadest sense of the term) this kind of discussion. It’s like a liberal stepping in and denouncing an evangelical’s arguing from Scripture because he/she sees it as extraneous to the real work to be done. For Anglicans, Scripture and Tradition both have an authoritative voice, even granting that some give Tradition more mileage than others. You’ve been around here long enough to know this, but you can’t seem to help from chastising those who won’t look at the matter through your particular Baptist (or whatever denomination’s) lenses. Sometimes I think you get us. Other times I realize we still speak different languages. [353] Posted by Fr. David McElrea (formerly farstrider+) on 9-2-2010 at 01:17 AM · [top] Carl, I have argued against it from scripture (where has the deacon the ‘authority’ to properly regulate the Lord’s Supper)? Will Sydney make it up of whole cloth, as those who support open WO do? [354] Posted by Bo on 9-2-2010 at 02:53 AM · [top] [353] farstrider I wasn’t terribly clear in that sentence. When I wrote ‘mindless assertion of tradition’ I would analogize the concept I had in mind to me simply asserting the authority of Scripture without ever actually quoting any Scripture. It was this particular set of questions from [338] that I had in mind. Do you defend tradition simply for the sake of defending it? What is the rationale behind the tradition? What do you lose by forsaking it? What do you gain by forsaking it? Why was this tradition established in the first place? This should be the ground of the argument. There are to my mind two coherent arguments that have been raised against Syndey’s proposal. 1. It will threaten church unity by repudiating the sacramental priesthood. 2. It will threaten church order by undermining the authority of the clergy. It is the later contention to which Sarah has alluded by saying that Sydney wants to eliminate the distinction between clergy and laity. She has justified this assertion by appeal to tradition, but she has never provided any actual substance to her argument. That is what I was talking about. The greater argument that should be addressed, but will not be addressed would involve answering David’s two questions from [337]: You accuse those who support diaconal administration as violating Scripture. As above, I would ask where does the Scripture actually proscribe such a course of actions? You accuse those who support diaconal administration as violating Tradition. As above, I would ask why are we bound to Tradition where it places a burden on us not actually found in Scripture? When those questions are asked (especially the second), the response is fulminating rage. One suspects the rage is meant to cover the weakness of the authority. Anglicans may have a concept of Tradition, but it is certainly not the Sacred Tradition that is found in Rome. Anyway, It’s nice to know I am at least a little appreciated. carl [355] Posted by carl on 9-2-2010 at 08:11 AM · [top] [354] Bo I have argued against it from scripture (where has the deacon the ‘authority’ to properly regulate the Lord’s Supper)? That is not an argument from Scripture. That is an argument from silence. Where does the Scripture assert that only Elders may administer Communion? It simply doesn’t. carl [356] Posted by carl on 9-2-2010 at 08:17 AM · [top] It does assert that elders have authority, and are to watch over our souls, and that communion taken unworthily is deadly. 1 Corinthians 11:29-30 My Argument, as with all novelties, is ‘show me the text’. We know to whom authority is given (elders/presbyters/pastors/shepherds/bishops) from scripture. Show me text before you add deacons to the list of those who are to shepherd my soul. [357] Posted by Bo on 9-2-2010 at 10:20 AM · [top] Carl, Why do you want the Anglican church to abandon the doctrinal understanding of Thomas Cranmer, and of continental reformers with whom Cranmer corresponded, notably John Calvin? That is a major issue here which you just seem to be ignoring. Cranmer and Calvin (following scripture) laid down a polity whereby presbyters preside over Holy Communion and deacons assist in that function (and of course many others as well). If a whole church is organised on that form of church government, why on earth should one diocese change it, for no apparent reason? It is the lack of apparent reason which leads many of us to be concerned that it is really Women’s Ordination “by stealth”. What is your problem with Cranmer and Calvin? I don’t understand. [358] Posted by MichaelA on 9-2-2010 at 04:38 PM · [top] [358] MichaelA Why do you want the Anglican church to abandon the doctrinal understanding of Thomas Cranmer, and of continental reformers with whom Cranmer corresponded, notably John Calvin? I don’t necessarily want the Anglican church to abandon anything. It isn’t my purpose to say that Sydney is right or wrong. In fact, I have never advocated for Sydney’s position in any of the threads on this subject. So then what am I doing? 1. You might have noticed the long list of allies that David Ould has on these threads, which besides me ... is ... well ... no one. At least I can’t think of another. David (and by extension Sydney) is making an argument to which I am theologically sympathetic. It’s a serious argument, and it deserves both a hearing and a defense. I simply can’t let him stand alone on this matter. In some sense, I hesitate to say this because I can just hear people saying “See, David? See? The only ally you can find isn’t even Anglican!” But since Sarah has already played that card, I guess it doesn’t matter. 2. It’s important to establish the difference between Scripture and Tradition. Only Scripture binds the conscience. If Scripture says “Thou shalt not ...” there is no option to say “Maybe we should reconsider this idea.” Whether we like it or not, we are bound to submit to its imperatives. Tradition on the other hand applies probative weight. Tradition is not a source of theology. It does not provide us knowledge of God. It gives us knowledge of the ideas and practices of past generations. This means that tradition (unlike Scripture) does not foreclose an argument. We are free to challenge and ultimately overturn a tradition. This means engaging in an argument to uncover the purpose and benefit and cost of the tradition. In effect, the tradition becomes the voice of the dead in a conversation that spans time. Such a voice is important to reveal the unobserved biases that we the living bring to the conversation, but it is not a voice of ultimate authority. Too much of the case against Sydney is presented from a presumed authority of Tradition that does not exist and should not be acknowledged. You can’t just claim that tradition closes the case. You have to justify that the tradition is still worthy of being upheld. That means respecting those who are questioning the tradition, and doing them the honor of examining the tradition from first principles. It does not mean saying “How dare you question these thing! We are Anglicans, and that means we have our traditions, and if you don’t like it then you should just go find another church!” 3. Much has been made of the impact that would be inflicted on the rest of the Anglican world if Sydney enacts this proposal. I wonder what this impact would be, and how it could possibly be greater than the impact of allowing both Catholic and Protestant concepts of priesthood in the same church. This makes me suspect the true fear is not theological in nature, but in fact clerical in nature. The people who run the church are worried that this act will undermine the authority of clergy. As in “Why, if you do this, then the masses will think they are as good as us, and then they will end up full of themselves, and get uppity, and start thinking they can act above their station. That way is chaos and ruin!” Deep down, I believe that is the actual pulsating fear-driven response to Sydney’s action, and the explanation for why it produces such a vehement reaction. I hope this clarifies my participation. I am honestly not pulling for Sydney to either enact or not enact this proposal. I am defending the right of Sydney to bring this proposal to light, and receive a respectful hearing. I am defending the right of Sydney to act in Christian freedom if it so sees fit. They may be cast out for doing so, but it will be a hypocritical act by a church that otherwise manages to fudge the difference between Catholic and Protestant concepts of priesthood. If it can tolerate that glaring inconsistency, then certainly it should be able to find a place for Sydney. carl [359] Posted by carl on 9-2-2010 at 06:57 PM · [top] Only Scripture binds the conscience. Including obeying the lawful authority? The Anglican view (as against the anabaptists) is firstly that the lawful authority may order the church in any way consonant with Scripture and enforce uniformity in accordance with such lawful authority. Secondly that the three fold ordering of ministers is, rightly interpreted, consonant with Scripture. Denying either of these truth claims is viewed as heretical by the mainstream Reformation in England. [360] Posted by driver8 on 9-2-2010 at 07:15 PM · [top] [360] driver8 [L]awful authority may order the church in any way consonant with Scripture and enforce uniformity Has Sydney been accused of acting unlawfully, or is it now a violation of lawful authority to question a tradition? [T]he three fold ordering of ministers is, rightly interpreted, consonant with Scripture. That’s a nice assertion, but it is exegetically false. There are two offices presented in Scripture, and not three. I have seen some arguments by inference that attempt to justify the office of bishop, but said office does not exist in the Pastoral Epistles. This is simply not debatable. Denying either of these truth claims is viewed as heretical The second being an excellent example of why tradition cannot be binding and cannot be used to define heresy. carl [361] Posted by carl on 9-2-2010 at 07:40 PM · [top] Carl and those supporting this ‘Sydney Plan’, Do you disagree with the statement that the presbyter/pastor/priest/shepherd/bishop is the office with authority in the local church, and the deacon is an office under that authority? Do you disagree with the idea that authority is to be exercised by the church with regard who may or may not communion? [362] Posted by Bo on 9-2-2010 at 08:34 PM · [top] [362] Bo ... and those supporting this ‘Sydney Plan’ ... [looking around] ... [chirping crickets] ... You mean me, right? Do you disagree with the statement that the presbyter/pastor/priest/shepherd/bishop is the office with authority in the local church, and the deacon is an office under that authority? No. Bishop is a traditional office, of course. Do you disagree with the idea that authority is to be exercised by the church with regard who may or may not [take?] communion? Given my assumption about the missing word, no. carl [363] Posted by carl on 9-2-2010 at 08:50 PM · [top] #361 I haven’t argued that tradition has any authority. I have argued : 1. that Scripture teaches Christians to obey lawful authority (eg Homily X in the First Book of Homilies) 2. that the mainstream COE Reformers viewed seveal patterns of church ordering, including the three fold ordering, as consonant with Scripture. 2. that within these limits, church ordering falls within the legitimate jurisdiction of the relevant lawful authority. (Art. XXXIV and XXXVII) Thus having made that argument, I have several times in this thread suggested that Sydney does not in fact possess the relevant jurisdiction. I see, you disagree with 2. In so doing you disagree with every mainstream English COE reformer. It’s no surprise then that you’re not Anglican. It would be more surprising if such a view were to be held by folks asserting the general truthfulness of the COE reformers’ views. [364] Posted by driver8 on 9-2-2010 at 09:08 PM · [top] Carl, I’m sure there are more than you supporting the ‘new thang’ in Sydney, whatever reason they have being quite (One is internet deprived at the time, I think…) Where is my logic flawed? (real question, I did OK in boolean logic for programming, but ‘formal logic’ is another beastie!) You agree with point one (Deacons haven’t authority in the church). You agree with point two (Authority must be exercised by the church when the Lord’s Supper is taken). Yet you don’t agree with the conclusion that deacons can’t be ‘in charge’ when the Lord’s Supper is taken. Too me it seems to flow from scripture that this innovation is ‘counter to the text’, not because their is nothing saying ‘deacons can’t lead the Lord’s Supper’, but because there is text that defines authority in the Church, and requires exercise of that authority when the Lord’s Supper is taken. Obviously I’m not getting that across well… [365] Posted by Bo on 9-2-2010 at 09:10 PM · [top] Carl, 1. You seem to answer every question except the one I asked. Please stop dodging the issue – several (at least a dozen) members have asked searching questions about Sydney’s actions from an evangelical or Anglican reformation perspective, and you don’t appear to be prepared to respond to them. 2. You wrote: “You might have noticed the long list of allies that David Ould has on these threads, which besides me ... is ... well ... no one.” That is not correct at all. Firstly, the tone of most of the posts has been that of querying a brother, not confronting an adversary. David Ould is of course held in very high regard personally, but most of the posts also demonstrate deep respect for Sydney Diocese as well. Several posts say so explicitly – how often do they have to write this before the message sinks in? Secondly, there have actually been at least three other members from Sydney Diocese (apart from David and myself) contributing to these threads, including a lecturer from Moore College, and they have defended Sydney’s position. 3. You also wrote: “It’s important to establish the difference between Scripture and Tradition…” Of course. So why are you denigrating those of us who firmly hold to the solas of the reformation, and yet still have serious problem with Sydney’s actions? You cannot have failed to read post after post written from an evangelical/reformed perspective and which query Sydney’s decision. So stop pretending that those people are all closet disciples of Tomas de Torquemada. 4. You also wrote: “Too much of the case against Sydney is presented from a presumed authority of Tradition that does not exist and should not be acknowledged”. Actually, very little of it has been presented from that perspective. Most of the posts on the Stand Firm threads seem to have been written from an evangelical or Anglican reformed perspective. Rather, it appears that you only want to debate those who believe in Apostolic Tradition and you refuse to acknowledge that there are plenty of evangelicals with real concerns about Sydney’s actions. 5. Now I will ask the questions again: (a) Thomas Cranmer and the other Anglican reformers laid down a system of church government wherein Presbyters administer Holy Communion, and Deacons *assist* the Presbyter to administer Holy Communion. Why does Sydney want to change that? (b) John Calvin in Geneva followed the same system: Presbyters administer Holy Communion; Deacons assist the Presbyter but do not themselves do the administering. Again, why would Sydney want to depart from a system endorsed by Calvin? (c) Both Cranmer and Calvin didn’t just adopt this polity by accident – Calvin in particular gives detailed reasoning from scripture and from church history why this is the correct way to do it. Have you read Calvin’s reasoning on this (its all in Book IV chapter 3 of the Institutes)? (d) The fact that Dio. Sydney doesn’t seem to be able to come up with convincing reasons as to why it needs to change the Anglican system of church government (i.e. its own system of church government for the past 200+ years) raises real concerns that there is some other motivation driving this. I, in particular, as a Sydney Anglican, am concerned that what is really happening is “Women’s Ordination by stealth”. [366] Posted by MichaelA on 9-2-2010 at 10:26 PM · [top] [366] MichaelA Please stop dodging the issue I never intentionally dodge the issue. I spent a good amount of time on that post with the intent of fairly addressing your questions. I obviously failed. I have also made you angry for which I apologize. It was never my intent to denigrate ether you or your concerns. Let me try again. First I will address your four questions. Please accept that there is no flippancy intended in these answers. Thomas Cranmer and the other Anglican reformers laid down a system of church government wherein Presbyters administer Holy Communion, and Deacons *assist* the Presbyter to administer Holy Communion. Why does Sydney want to change that? Ask Sydney. I am not advocating for their position. You will search in vain through my comments to find a statement like “Sydney should approve lay presidency.” John Calvin in Geneva followed the same system: Presbyters administer Holy Communion; Deacons assist the Presbyter but do not themselves do the administering. Again, why would Sydney want to depart from a system endorsed by Calvin? Ask Sydney. I am not advocating for their position. You will search in vain through my comments to find a statement like “Sydney should approve lay presidency.” Both Cranmer and Calvin didn’t just adopt this polity by accident – Calvin in particular gives detailed reasoning from scripture and from church history why this is the correct way to do it. Have you read Calvin’s reasoning on this (its all in Book IV chapter 3 of the Institutes)? Ask Sydney. I am not advocating for their position. You will search in vain through my comments to find a statement like “Sydney should approve lay presidency.” The fact that Dio. Sydney doesn’t seem to be able to come up with convincing reasons as to why it needs to change the Anglican system of church government (i.e. its own system of church government for the past 200+ years) raises real concerns that there is some other motivation driving this. I, in particular, as a Sydney Anglican, am concerned that what is really happening is “Women’s Ordination by stealth”. Ask Sydney. I am not advocating for their position. You will search in vain through my comments to find a statement like “Sydney should approve lay presidency.” I had hoped to communicate this in my first response. As I have said repeatedly, I am not trying to convince anyone that Sydney is correct. I am instead saying the following: 1. There is no Scriptural impediment to this proposal. I am not unique on these threads by saying so. 2. The lack of Scriptural impediment means that the proposal is properly classified as a matter of Christian freedom. I am not unique on these threads by saying so. 3. Opposition to this proposal be it ever so well-reasoned does not and can not originate from a source of authority that compels Sydney to withdraw this proposal. 4. There is no basis therefore to impose sanction on Sydney should this proposal be enacted - and certainly not given the fact that a sacramental priesthood is accepted without troubled conscience. Now let me address a few other matters. That is not correct at all. Firstly, the tone of most of the posts has been that of querying a brother, not confronting an adversary. David Ould is of course held in very high regard personally, but most of the posts also demonstrate deep respect for Sydney Diocese as well. Several posts say so explicitly – how often do they have to write this before the message sinks in? When I wrote ‘ally’ I meant someone who was saying something besides “Sydney shouldn’t do this.” Before I wrote that line I scanned my memory and couldn’t come up with anyone else. Memories are fallible, of course, and the perception of feeling alone can certainly distort one’s perspective. That’s why I added At least I can’t think of another. If I was wrong, I will certainly admit it. But I am not too far wrong. There are very few people on SFIF who do not oppose Sydney on this matter.So why are you denigrating those of us who firmly hold to the solas of the reformation, and yet still have serious problem with Sydney’s actions? Point out where I have denigrated you, and I will withdraw it. Such was never my intent. It makes perfect sense to me that many people will have serious problems with Sydney’s actions, and therefore oppose it. What makes no sense to me at all is that people would threaten to break communion over this subject. It is patently ridiculous to suggest that Sydney is just like TEC in this matter - going its own way. Upon what grounds are they being condemned in such a manner? It is certainly not Scripture that Sydney seeks to overturn. What then does it seek to overturn? You say the conflict is not about the authority of tradition… Actually, very little of it has been presented from that perspective. Most of the posts on the Stand Firm threads seem to have been written from an evangelical or Anglican reformed perspective. Rather, it appears that you only want to debate those who believe in Apostolic Tradition and you refuse to acknowledge that there are plenty of evangelicals with real concerns about Sydney’s actions. ... and yet I see no other authority in play. Criticizing this proposal from a Reformed Evangelical Anglican perspective does not change the fact that no Scriptural imperative binds Sydney to stop. It simply means you are criticizing this idea from an implicit Reformed Evangelical Anglican tradition. You are not wrong as a result, but you also cannot assert “It is written!” This is why David asked these two questions that have never been answered directly: You accuse those who support diaconal administration as violating Scripture. As above, I would ask where does the Scripture actually proscribe such a course of actions? You accuse those who support diaconal administration as violating Tradition. As above, I would ask why are we bound to Tradition where it places a burden on us not actually found in Scripture? Those questions are the issue to me. Those questions are why I have participated in this thread, and others like it. carl [367] Posted by carl on 9-3-2010 at 12:15 AM · [top] Again—understanding that there is no persuading of Carl—to respond yet once more to his assertions for the sake of clarity: RE: “There is no Scriptural impediment to this proposal.” Irrelevant even if granted. RE: “The lack of Scriptural impediment means that the proposal is properly classified as a matter of Christian freedom.” Irrelevant even if granted. RE: “Opposition to this proposal be it ever so well-reasoned does not and can not originate from a source of authority that compels Sydney to withdraw this proposal.” Well, the only thing that could compel Sydney to withdraw the proposal—unlikely but still maybe—would be the authority of the Anglican Communion. “Compel” is a strong word—“persuade” might be a better word. But if one insists on using the word “compel” than yes—*nothing* can “compel” Sydney to do anything. Therefore irrelevant, even if granted. RE: “There is no basis therefore to impose sanction on Sydney should this proposal be enacted - and certainly not given the fact that a sacramental priesthood is accepted without troubled conscience.” An interesting use of the word “therefore” since the first three points have absolutely nothing to do with whether there is a “basis” to impose sanction. Sydney is a part of the Anglican Communion. The Anglican Communion has determined a number of matters that are intrinsic to being in the Anglican Communion, among them a baseline reegarding the clergy, ordination, laity, sacraments, and the place of Church tradition. [The acceptance of a sacramental priesthood, or goat sacrifice, or Incan virgin sacrifice, or TEC gay-all-the-time has nothing whatsoever to do with anything.] If Sydney desires to be a part of an organization that has made the place and identity of the clergy/sacraments/etc crystal clear, time after time after time, then it will need to adhere to accepted and long-spelled-out practices. That is not a denial of Sydney’s “Christian freedom”—it is free to be Christian within any organization that will accept it and its practices. There are plenty of Christian organizations that have various rules for belonging that may also demand or reject practices that “have no Christian impediment.” In fact, I would venture to suppose that every single Christian denomination has requirements against practices for which there is “no Scriptural impediment.” If Christians wish to practice certain things that those organizations do not allow—for example, if I wish to follow David’s time-honored act of worship by dancing half-naked in front of the people—then those Christians will need to move to another organization that allows those practices. In the case of lay administration one is hard-pressed to come up with such a Christian organization—perhaps we can recommend the Plymouth Brethren, as that is the only one that springs to mind. [368] Posted by Sarah on 9-3-2010 at 12:36 AM · [top] Carl, You wrote (several times): Ask Sydney. I am not advocating for their position. You will search in vain through my comments to find a statement like “Sydney should approve lay presidency.” This is not correct. You have continually asserted that Sydney is entitled to approve lay presidency. At least have the decency, integrity and honour to admit the position that you have advocated throughout. “The lack of Scriptural impediment means that the proposal is properly classified as a matter of Christian freedom.” This is not a scriptural teaching. “Christian freedom” may be limited by many things. For one thing, we are specifically forbidden to exercise any christian freedom if it may cause a brother to stumble [e.g. Romans 14:19-21]. For another, the Apostle Paul in several places emphasises that the affairs of churches should be conducted decently and in order [e.g. 1 Cor 14:26-39]. It is therefore perfectly legitimate for other Anglicans to ask advocates of diaconal administration why they are departing from the clear teaching of the Anglican and continental reformers. If Sydney did not claim to be Anglican, this question would not matter. But in fact Sydney is proudly Anglican, and I have asked this question because I know that it is one that will trouble many Sydney Anglicans. It is a question that the advocates of diaconal administration have been avoiding. [369] Posted by MichaelA on 9-3-2010 at 01:18 AM · [top] [369] MichaelA This is not correct. You have continually asserted that Sydney is entitled to approve lay presidency. At least have the decency, integrity and honour to admit the position that you have advocated throughout. Yes, I have continually asserted that Sydney is entitled to approve lay presidency. That is not the same as saying it should approve lay presidency. And, actually, I believe I have conducted myself with decency, integrity and honor on this thread. carl [370] Posted by carl on 9-3-2010 at 07:22 AM · [top] Carl, You can PM the answer to my question in 365…. I really do wish to know…. [371] Posted by Bo on 9-3-2010 at 10:49 AM · [top] [365] Bo I don’t accept the idea that one in authority must be present to exercise that authority. As it is written: [Jesus] was not far from the house when the centurion sent friends to say to him: “Lord, don’t trouble yourself, for I do not deserve to have you come under my roof. That is why I did not even consider myself worthy to come to you. But say the word, and my servant will be healed. For I myself am a man under authority, with soldiers under me. I tell this one, ‘Go,’ and he goes; and that one, ‘Come,’ and he comes. I say to my servant, ‘Do this,’ and he does it.” Luke 7:6-8 NASB In otherwords, I allow for the possibility that good order can be maintained in the stead of the priest. I have more to say, but at this point I do not want to put the rest of my reasoning on this or any other thread on this subject. So look for a PM. carl [372] Posted by carl on 9-3-2010 at 12:19 PM · [top] My question remains to the proponents of Diaconal Administration in the Diocese of Sydney: What is the reason for changing a principle of church order and government which Sydney has adhered to for over two centuries, and which was established by the Anglican and continental reformers? What is the real reason for changing the order established by Cranmer and Calvin? 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https://topanswers.xyz/tex?q=494 | or
CarLaTeX
tikz
As you can see, the VaR tick is longer than the one under the y axis.
How can I have them equals without manually drawing the tick under the y axis?
P.S. = The skewed Normal distribution is from https://tex.stackexchange.com/a/461839/101651.
~~~
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\l = abs(\l);
\e = exp(-(\x^2)/2);
return (\l == 0) ? 1 / sqrt(2 * pi) * \e: (
(\x < -3/\l) ? 0 : (
(\x < -1/\l) ? \e / (8 * sqrt(2 * pi)) * h1(\x, \x*\l) : (
(\x < 1/\l) ? \e / (4 * sqrt(2 * pi)) * h2(\x, \x*\l) : (
(\x < 3/\l) ? \e / (8 * sqrt(2 * pi)) * h3(\x, \x*\l) : (
sqrt(2/pi) * \e)))));
};
}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
assi,
enlarge x limits={value=.04,upper},
enlarge y limits={value=.02,lower},
ymax=.73,
xscale=1.2,
xlabel = {Loss},
x label style={at=(current axis.right of origin),
anchor=west},
ylabel = {Probability\\ density},
y label style={%at=(current axis.above origin),
anchor=north east, align=center, %inner sep=0pt
},
]
\pgfmathsetmacro{\limiteinf}{-1.9}
\pgfmathsetmacro{\limitesup}{2.8}
\pgfmathsetmacro{\VaRx}{1.6}
\pgfmathsetmacro{\VaR}{skewnorm(\VaRx+.6,2)}
\begin{scope}[on background layer]
{skewnorm((x+.6), 2)} \closedcycle;
\end{scope}
\draw (axis cs:\VaRx,0) -- (axis cs:\VaRx,\VaR);
\draw (axis cs:\VaRx,0) -- (axis cs:\VaRx,-.02)
node[below=4pt, inner sep=0pt] {$\mathrm{VaR}_\alpha$};
\node (unomenoalfa) at (axis cs:2.3,0.12) {$1-\alpha$};
\draw[-Stealth] (unomenoalfa) -- (axis cs:1.7,0.015);
\end{axis}
\end{tikzpicture}
\end{document}
~~~
samcarter
Not sure if this counts as "not drawing it manually", but at the moment, the line below the origin comes from enlarge y limits={value=.02,lower}. You could instead set ymin to the same value as your tick at VaR.
The reason enlarge y limits={value=.02,lower} did not work as expected is that this seems to be a relative value. From the pgfplots docu:
> \pgfplotsset{enlarge x limits={value=0.2,upper}} will enlarge (only) the upper axis limit by 20% of the axis range.
\documentclass[11pt]{standalone}
% tikz
\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{arrows.meta}
\usetikzlibrary{positioning}
\usetikzlibrary{backgrounds}
\pgfplotsset{
assi/.style={
axis lines=middle,
axis line style={-Stealth},
ticks=none,
samples=300,
clip=false,
},
}
\usetikzlibrary{math}
\tikzmath{%
function h1(\x, \lx) { return (9*\lx + 3*((\lx)^2) + ((\lx)^3)/3 + 9); };
function h2(\x, \lx) { return (3*\lx - ((\lx)^3)/3 + 4); };
function h3(\x, \lx) { return (9*\lx - 3*((\lx)^2) + ((\lx)^3)/3 + 7); };
function skewnorm(\x, \l) {
\x = (\l < 0) ? -\x : \x;
\l = abs(\l);
\e = exp(-(\x^2)/2);
return (\l == 0) ? 1 / sqrt(2 * pi) * \e: (
(\x < -3/\l) ? 0 : (
(\x < -1/\l) ? \e / (8 * sqrt(2 * pi)) * h1(\x, \x*\l) : (
(\x < 1/\l) ? \e / (4 * sqrt(2 * pi)) * h2(\x, \x*\l) : (
(\x < 3/\l) ? \e / (8 * sqrt(2 * pi)) * h3(\x, \x*\l) : (
sqrt(2/pi) * \e)))));
};
}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
assi,
enlarge x limits={value=.04,upper},
% enlarge y limits={value=.03,lower},
ymin=-0.02,
ymax=.73,
xscale=1.2,
xlabel = {Loss},
x label style={at=(current axis.right of origin),
anchor=west},
ylabel = {Probability\\ density},
y label style={%at=(current axis.above origin),
anchor=north east, align=center, %inner sep=0pt
},
]
\pgfmathsetmacro{\limiteinf}{-1.9}
\pgfmathsetmacro{\limitesup}{2.8}
\pgfmathsetmacro{\VaRx}{1.6}
\pgfmathsetmacro{\VaR}{skewnorm(\VaRx+.6,2)}
\begin{scope}[on background layer]
{skewnorm((x+.6), 2)} \closedcycle;
\end{scope}
\draw (axis cs:\VaRx,0) -- (axis cs:\VaRx,\VaR);
\draw (axis cs:\VaRx,0) -- (axis cs:\VaRx,-.02)
node[below=4pt, inner sep=0pt] {$\mathrm{VaR}_\alpha$};
\node (unomenoalfa) at (axis cs:2.3,0.12) {$1-\alpha$};
\draw[-Stealth] (unomenoalfa) -- (axis cs:1.7,0.015);
\end{axis}
\end{tikzpicture}
\end{document}
How can I have the tick under the y axis equal to the tick of a label?
Yes. It only happens if you use larger values, which however can happen very easily. (I had some bitter experience with that using some recursive function. The recursion required tikzmath, but tikzmath is not compatible with fpu, at least not with fpu the way I tryied to use at that time.)
I used it because I copied it :). I use standalone and then include the output pdf in the main document, till now I didn't find any problem.
@CarLaTeX I'd like to discourage you from using tikzmath for pgfplots. AFAIK this does not really use the fpu machinery, so you may easily get dimension too large errors, | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9204636812210083, "perplexity": 18257.61244104569}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585370496669.0/warc/CC-MAIN-20200330054217-20200330084217-00311.warc.gz"} |
https://mcqexams.com/cbse/mcq-questions-for-class-11-medical-physics/ | # MCQ Questions for Class 11 Medical Physics Quiz with Answers Chapter Wise PDF Download
CBSE Multiple Choice Type Questions for 11th Class Medical Physics PDF formatted study resources are available for free download. These Grade 11 Medical Physics CBSE MCQ Mock Test helps you learn & practice the concepts in a fun learning way.
## Class 11 Medical Physics MCQs Multiple Choice Questions with Answers
Here are the chapterwise CBSE MCQ Quiz Test Questions for Class 11th Medical Physics in pdf format that helps you access & download so that you can practice online/offline easily.
### Gravitation Questions and Answers
Gravitation Quiz Question Answer
A man is standing on an international space station, which is orbiting earth at an altitude 520$$\mathrm { km }$$ with a constant speed 7.6 $$\mathrm { km } / \mathrm { s }$$ . If the men's weight is 50$$\mathrm { kg }$$ , his acceleration is 8.4$$m / s ^ { 2 }$$
In the usual notation, the acceleration due to gravity at a height $$h$$ from the surface of the earth is ......... $$g= \frac{GM}{(R+h)^2}$$
The value of the acceleration due to gravity at a height from Earth's surface decreases by $$1\%$$. What will be the value of height from the surface?(Take the radius of earth =$$6400\ km$$) $$32\ km$$
If the acceleration due to gravity at a height 'h' from the surface of the earth is $$96$$% less than its value on the surface, then h= ______R where R is the radius of the earth. $$4$$
The change in the value of $$^ { \prime } g ^ { \prime }$$ at a height $$^ { \prime }$$ h'above the surface of the earth is same as at a depth 'd'. If d and h are much smaller than the radius of earth, then which one of the following is correct?
$$d=2h$$
A particle would take a time $$t$$ to move down a straight tube from the surface of earth (supposed to be a homogeneous sphere) to its centre. If gravity were to remain constant, then the time would be $$t$$. The ratio of $$t/t$$ will be $$\dfrac{ \pi }{ 2\sqrt { 2 } }$$
A satellite is revolving around Earth in a circular orbit whose radius is R.work done by gravitational force in one revolution is zero
Which of the following laws are conserved, if the areal acceleration is zero Law of conservation of angular momentum
The gravitational potential energy is the work done in bringing an object from infinity to radius r
Earth can be considered as uniform solid sphere of radius $$R. g_{1}$$ and $$g_{2}$$ be acceleration due to gravity at points $$R/2$$ below the surface and $$R/2$$ above the surface of earth respectively. Then $$\dfrac {g_{1}}{g_{2}}$$ equals to $$\dfrac {9}{8}$$
### Kinetic Theory Questions and Answers
Kinetic Theory Quiz Question Answer
A helium-filled latex balloon initially at room temperature is placed in a freezer. The latex remains flexible. The balloon’s volume decrease
One kg of a diatomic gas is at a pressure of $$8\times {10}^{4}N/{m}^{2}$$. The density of gas is $$4kg/{m}^{2}$$. What is the energy of the gas due to its thermal motion? $$5\times {10}^{4}J$$
If temperature of body increases by 10%, then increase in radiated energy of the body is : 46 %
A thin walled hollow cylinder is rolling down an incline , without slipping. At any instant, without slipping. At any instant the ratio "Rotational K.E : Translational K.E : Total K.E" is $$2 : 1 : 3$$
A gas undergoes a process such that $$P \propto \dfrac{1}{T}$$. If the molar heat capacity for this process is $$24.93 \,J/mol \,K$$, then what is the degree of freedom of the molecules of the gas? $$2$$
If water at $$0^0C$$, kept in a container with an open top, is placed in a large evacuated chamber, part of the water will vaporize and the rest will freeze
Hydrogen is a diatomic gas. Its molar specific heat at constant volume is very nearly $$\frac { 5 R } { 2 }$$
Half mole of an ideal monoatomic gas is heated at constant pressure of 1 atm from $${ 20 }^{ 0 }C$$ to $${ 90 }^{ 0 }C$$ . Work done by gas is close to : ( gas constant R=8.31 j / mol -k ) 581 j
Who amongst the following shows lowest tendency towards reduction in gaseous state. Se
The mean free path of nitrogen molecules at a pressure of 1.0 atm and temperature $$0^0 C$$ is $$0.8 \times 10^{-7} m$$. If the number of density of molecules is $$2.7 \times 10^{25}$$ per $$m^3$$, then the molecular diameter is $$3.2 A^0$$
### Laws Of Motion Questions and Answers
Laws Of Motion Quiz Question Answer
If an external force and the frictional force acting on a body cancel each other the frictional force is Static friction
A uniform rod of mass M has an impulse applied at right angles to one end. If the other end begins to move with speed V, the magnitude of the impulse is $$\cfrac {2MV} {3}$$
What is product of force and the time for which force act called?
Impulse of force
The momentum of the body does not depend on- acceleration of the body
For which type of surface magnitude of frictional force would be less?
Glass surface
Momentum gives the measure of the quantity of motion
In kinetic theory of gases , a molecule of mass $$m$$ of an ideal gas collides with a wall of vessel with velocity $$V$$. The change in the linear momentum of the molecule is $$2 \,mV$$
The total momentum of the molecules of $$1\,gm\, mol$$of a gas in a container at rest of $$300\,K$$ is Zero
Impulse is equal to
change in momentum
A $$10$$ gm bullet is fired from a rifle horizontally into a $$5$$ kg block of wood suspended by a string and the bullet gets embedded in the block. The impact causes the block to switch to an a height of $$2.5$$ cm above its initial level. The velocity of the bullet is $$1000$$m/sec
### Mechanical Properties Of Fluids Questions and Answers
Mechanical Properties Of Fluids Quiz Question Answer
A metal ball is being weighed in a liquid whose temperature is raised continuously. Then the apparent weight of the ball : increases
A man of mass 100 kg stands on a wood plank of area $$4\, m^2$$. What is the pressure exerted on the floor? Assume the area of a human foot to be $$200\, cm^2$$. 250 N
The base area of a boat is $$2m^{2}$$. A man weighing $$76kg$$ weight steps in to the boat. Calculate the depth in to which the boat sinks further in to water. $$3.8\ cm$$
An orifice of area $$10sq.mm$$ is made at the bottom of a vessel containing water to a height of $$10m$$ above the orifice. What is the force on the vessal $$1.96N$$
A liquid is coming out from the orifice of tank and falls up to a maximum horizon distance of $$6m$$ . The height $$h$$ is equal to $$3.0m$$
Barometer was constructed by : Torricelli
The height up to which water will rise in a capillary tube will be Minimum when water temperature is $$4^{\circ}C$$
Equal volumes of a liquid is poured into containers A and B such that the area of cross-section of container A is double the area of cross-section of container B. If $$P_A$$ and $$P_B$$ are the pressures exerted at the bottom of the containers then $$P_A : P_B =$$__________
1 : 2
For a liquid which is rising in a capillary, the angle of contact is Acute
As we go higher and higher atmospheric pressure _______. Decreases
### Mechanical Properties Of Solids Questions and Answers
Mechanical Properties Of Solids Quiz Question Answer
The bulk modulus of a spherical object is B. If it is subjected to uniform pressure p, the fractional decrease in radius is $$\frac{p}{3B}$$
A 2.0 m long steel cable has cross-sectional area of $$0.30 cm^2$$. A 550 kg load is now hung from the cable. Assume that the cable behaves like a solid rod with an uniform cross-sectional area. Then the stress of the cable is: $$1.8 \times 10^8 Pa$$
Two wires of same material and length but cross-sections in the ratio $$1:2$$ are used to suspend the same loads. The extensions in them will be in the ratio
$$2:1$$
The length of an iron wire is $$L$$ and area of cross-section is $$A$$. The increase in length is $$l$$ on applying the force $$F$$ on its two ends. Which of the statement is correct? Increase in length is inversely proportional to area of cross-section
Two wires are made of the same material and have the same volume. However wire 1 has cross-sectional area $$A$$ and wire 2 has cross- sectional area $$3A$$. If the length of wire 1 increases by $$\Delta \mathrm{x}$$ on applying force $$\mathrm{F}$$, how much force is needed to stretch wire 2 by the same amount ?
$$9\mathrm{F}$$
At $$40^oC$$, a brass wire of $$1 mm$$ radius is hung from the ceiling. A small mass, $$M$$ is hung from the free end of the wire. When the wire is cooled down from $$40^oC$$ to $$20^oC$$ it regains its original length of $$0.2 m$$. The value of $$M$$ is close to :
(Coefficient of linear expansion and Young's modulus of brass are $$10^{-5} / ^oC$$ and $$10^{11} \ N/m^2$$, respectively; $$g = 10 ms^{-2}$$)
$$9 \ kg$$
A uniformly tapering conical wire is made from a material of Young's modulus $$Y$$ and has a normal, unextended length $$L$$. The radii, at the upper and lower ends of this conical wire, have values $$R$$ and $$3R$$, respectively. The upper end of the wire is fixed to a rigid support and a mass $$M$$ is suspended from its lower end. The equilibrium extended length, of this wire, would equal to:
$$L\left( 1+\dfrac { 1 }{ 3 } \dfrac { Mg }{ \pi \Upsilon { R }^{ 2 } } \right)$$
A thin 1 m long rod has a radius of 5 mm.1 A force of 50 $$\pi kN$$ is applied at one end to determine its Young's modulus. Assume that the force is exactly known. If the least count in the measurement of all lengths is 0.01 mm, which of the following statements is false ?
The maximum value of Y that can be determined is $$10^{14} N/m^2$$.
If speed(V), acceleration(A) and force(F) are considered as fundamental units, the dimension of Young's modulus will be? $$V^{-4}A^2F$$
A bottle has an opening of radius $$a$$ and length $$b$$. A cork of length $$b$$ and radius $$(a+ \Delta a)$$ where $$(\Delta a << a)$$ is compressed to fit into the opening completely (See figure). If the bulk modulus of cork is B and the frictional coefficient between the bottle and cork is $$\mu$$ then the force needed to push the cork into the bottle is :
$$(4\pi \mu B b)\Delta a$$
### Motion In A Plane Questions and Answers
Motion In A Plane Quiz Question Answer
The minimum number of vectors of unequal magnitude required to produce a zero resultant is : $$3$$
A single velocity time graph can be drawn for 1 dimension only.
Which of the following motions is different from the rest? a bird flying in the air
A fly wheel rotating at 600 rev/min is brought under uniform deceleration and stopped after 2 minutes, then what is angular deceleration in $$rad/sec^2$$? $$\frac{\pi}{6}$$
What is the rage of a projectile thrown with velocity $$98 \,m/sec$$ with angle $$30^o$$ from horizontal? $$490\sqrt{3}$$ meter
A curved section of road is banked for a speed v. if there is no friction between road and tyres of the car , then :
car is more likely to slip at speeds higher than V
At what angle 2 forces (P+Q) & (P-Q) act so that resultant is $$\sqrt{2} (p^2+ q^2)$$
A body of mass 1 kg is projected from the ground at an angle $${30^0}$$ with horizontal on the level ground at a speed 50m/s.
$$50kg\;m{s^{ - 1}}$$
Which of the following physical quantities is different from others?
Average velocity
A water fountain on the ground sprinkles water all around it. If the speed of water coming out of the fountain is $$v$$, the total area around the fountain that gets wet is : $$\displaystyle \pi\dfrac{\mathrm{v}^{4}}{\mathrm{g}^{2}}$$
### Motion In A Straight Line Questions and Answers
Motion In A Straight Line Quiz Question Answer
A man throws balls with the same speed vertically upwards one after the other at an interval of $$2$$ second. What should be the speed of the throw so that more than two balls are in sky at any time? (Given $$g=9.8$$ $${m/s^2}$$) Only with speed $$19.6$$ $${m/s}$$
A particle starts from rest and travels a total distance of 18m along a straight path.The first half of the distance was travelled with a uniform acceleration of 2 $$ms^{-2}$$ and the rest uniform velocity.The average velocity for the whole journey is (in $$ms^{-1}$$) 6
At any instant, the velocity and acceleration of a particle moving along a straight line v and a. The speed of the particle is increasing if v > 0, a > 0
A lizard, at an initial distance of $$21$$ cm behind an insect, moves from rest with an
acceleration of $$2 cm/s^{2}$$ and pursues the insect which is crawling uniformly along a
straight line at a speed of $$20$$ cm/s. Then the lizard will catch the insect after
$$21$$ s
Two points $$A$$ and $$B$$ move from rest along a straight line with same acceleration $$f$$ and $$f'$$ respectively. If $$A$$ takes $$m\ \text{sec}$$ more than $$B$$ and describes $$n$$ units more than $$B$$ in acquiring the same speed then $$(f^{'}-f)n=\frac{1}{2}ff^{'}m^{2}$$
Two stones are thrown up simultaneously from the edge of a cliff $$240\ m$$ high with initial speed $$10\ m/s$$ and $$40\ m/s$$ respectively. Which of the following graph best represents the time variation of relative position of the second stone with respect to the first ?
(Assume stones do not rebound after hitting the ground and neglect air resistance, take $$g = 10\ m /s^2$$)
(The figures are schematic and not drawn to scale.)
STATEMENT-1: For an observer looking out through the window of a fast moving train, the nearby objects appear to move in the opposite direction to the train, while the distant objects appear to be stationary.
STATEMENT-2:
If the observer and the object are moving at velocities $$\vec{\mathrm{V}}_{1}$$ and $$\vec{\mathrm{V}}_{2}$$ respectively with reference to a laboratory frame, the velocity of the object with respect to the observer is $$\vec{\mathrm{V}}_{2}-\vec{\mathrm{V}}_{1}$$.
STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1
A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field $$\overrightarrow{E}$$. Due to the force $$q\overrightarrow{E}$$, its velocity increases from $$0$$ to $$6\ m/s$$ in one-second duration. At that instant, the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the average speed of the toy car between $$0$$ to $$3$$ seconds are respectively: $$1$$ m/s, $$3$$ m/s
A ball is dropped from a bridge $$122.5 m$$ high. After the first ball has fallen for $$2 seconds$$, a second ball is thrown straight down after it, what must be the initial velocity of the second ball be, so that both the balls hit the surface of water at the same time? $$26.1 {m}/{s}$$
If a car at rest accelerated uniformly to a speed of $$144 {km}/{hour}$$ in $$20 second$$ it covers a distance: $$400 m$$
### Oscillations Questions and Answers
Oscillations Quiz Question Answer
If a body of mass 0.98 kg is made to oscillate on a spring of force constant 4.84 N/m, the angular frequency of the body is
State whether true or false.
Piston of the engine in a motor car exhibits Oscillatory motion.
True
A man of mass $$60 kg$$ is standing on a platform executing $$SHM$$ in the vertical plane. The displacement from the mean position varies as $$y=0.5 sin\left(2\pi ft \right)$$. The value of $$f$$, for which the man will feel weightlessness at the highest point, is (y in metre) $${ \dfrac{ \sqrt{2g} }{ 2\pi }}$$
A particle makes SHM along a straight and tis velocity when passing through point $$3cm$$ and $$4cm$$ from the mean position $$16mc/sec$$ and $$12cm/sec$$ respectively. then time period is $$\dfrac{\pi}{2}sec$$
A particle performing SIIM is found at its equilibrium at $$t = 1$$ sec and it is found to have a speed of $$0.25 \mathrm { m } / \mathrm { s }$$ at $$t = 2$$ sec. If the period of oscillation is $$6$$ sec . Calculate amplitude of oscillation
$$\frac { 3 } { 2 \pi } m$$
The equation of a particle executing SHM is $$\frac{2 d^{2} x}{d t^{2}}+32 x=0 .$$ Then the time period of the body is $$\frac{\pi}{2}$$
A stone is swinging in a horizontal circle $$0.8m$$ in diameter, at $$30rev/min$$. A distant light causes a shadow of the stone to be formed on a nearby wall. What is the amplitude of the motion of the shadow? What is the frequency? $$0.4m,0.5Hz$$
A particle executes SHM with an emplitude of 10 cm and frequency 2Hz. At t=0, the particle is at a point where speed is $$1\sqrt{2}$$ times of maximum speed. Which of these may be representing variation of displacement(x) with time (t)? (x) is measured from mean position $$x=0.1sin\left ( 4\pi t+\frac{\pi }{4} \right )$$
A particle performs simple harmonic motion with amplitude A. Its speed is tripled at the instant that it is at a distance $$\displaystyle\frac{2A}{3}$$ from equilibrium position. The new amplitude of the motion is. $$\displaystyle\frac{7A}{3}$$
A body is in simple harmonic motion with time period half second $$(T=0.5s)$$ and amplitude one cm $$(A=1 cm)$$. Find the average velocity in the interval in which it moves from equilibrium position to half of its amplitude. $$12 cm/s$$
### Physical World Questions and Answers
Physical World Quiz Question Answer
The Steam engine is based on which scientific principle? Laws of thermodynamics
The magnitude of non-contact force depends upon:
distance between two bodies
Name the Indian scientist who has contributed in the discovery of inelastic scattering of light by molecules. C.V. Raman
Which of the following is not correct about nuclear forces?
They are the short-range attractive force
No contact force acts on a bucket when it is being pulled out of a well using a rope False
What was the major contribution/discoveries of Archimedes? Principle of buoyancy; Principle of the lever
Earth pulls every object towards it with a force called: Gravity
Which of the following is true regarding the physical science? Both a and b
_____ suggested that the ships should be marked with load lines.
Samuel plimsoll
Earth has no gravitational force: False
### Systems Of Particles And Rotational Motion Questions and Answers
Systems Of Particles And Rotational Motion Quiz Question Answer
A potter's wheel has ______ motion rotatory
The moment of inertia of a fly-wheel is $$4\, kg\ m^2$$. A torque of $$10$$ Newton-meter is applied on it. The angular acceleration produced will be : $$2.5 \,radians/sec^2$$
The centre of a mass of a rigid body lies either $$(a)$$ or $$(b)$$
On doubling the speed of of an object its:
Momentum is doubled
A man weighing $$60kg$$ is standing on a trolley weighing $$240 kg$$. The trolley is resting on friction less horizontal rails. If the man starts walking on the trolley with a velocity of $$1ms^{-1}$$, then after $$4s$$, his dispalcement relative to the ground is $$1m$$
A body of mass 'm' falls from a height 'h' and rebounds. If 'e' is the coefficient of restitution between the ground and the body, the change in linear momentum of the body is $$m(1+e) \sqrt{2gh}$$
A girl seated on a stool that is free to rotate about a vertical axis holds a bicycle wheel rotating in a horizontal plane in clockwise direction. When see inverts the wheel upside down she rotates in clockwise direction along with the stool
Figure shows a thin metallic triangular sheet ABC. The mass of the sheet is M. The moment of inertia of the sheet about side AC is :
$$\frac{Ml^2 }{12}$$
A scalene triangular lamina of uniform mass density and negligible thickness has one of its vertices at the origin. The position vectors of its other two vertices are $$\vec a$$ and $$\vec b$$. The location of its centre of mass will be $$\frac{\vec a + \vec b}{3}$$
The angular speed of a body changes from $$\omega_1$$ to $$\omega_2$$ without applying a torque but due to change in its moment of inertia.the ratio of radii of gyration in the two cases is $$\sqrt \omega_2 : \sqrt \omega_1$$
### Thermal Properties Of Matter Questions and Answers
Thermal Properties Of Matter Quiz Question Answer
One mole of a perfect gas in a cylinder fitted with a piston has a pressure P, volume V and temperature is increased by 1 K keeping pressure constant , the increase in volume is $$\dfrac { V }{ 273 }$$
A marble tile would feel cold as compared to a wooden tile on a winter morning, because the marble tile is a better conductor of heat than the wooden tile.
A pond has an ice layer of thickness 3 cm. If K of ice is 0.005 CGS units, surface temperature of surroundings is $$-20^\circ C$$, density of ice is $$0.9 gm/cc$$, the time taken for the thickness to increase by 1 cm is 42 min
Which of the following is more close to a black body? Black holes
A gas is taken through cyclic process $$ABCA$$ is shown in figure. If $$2.4$$ cal of heat is given in the process, what is value of $$J$$?
$$\text{4.17 J/ cal}$$
At what temperature is the r.m.s velocity of a hydrogen molecule equal to that of an oxygen molecule at $${47}^{o}C$$? $$20K$$
The graph $$AB$$ shown in the figure is a plot of the temperature of a body in degree Celsius and degree Fahrenheit. Then
slope of line $$AB$$ is $$\dfrac {5}{9}$$
Two metal spheres have radii r and 2r and they emit thermal radiation with maximum intensities at wavelengths $$\lambda$$ and $$2\lambda$$ respectively. The respective ratio of the radiant energy emitted by them per second will be 4 : 1
When the temperature of a rod increases from $$T$$ to $$T+\Delta T$$, its moment of inertia increase from $$I$$ to $$I+\Delta I$$. If $$\alpha$$ is the coefficient of linear expansion of the rod, then the value of $$\cfrac{\Delta I}{I}$$ is: $$2\alpha \Delta T$$
Radius of the sun is $$7\times { 10 }^{ 8 }m$$ and the energy radiated by it is $$38\times { 10 }^{ 28 }W$$. Calculate the magnitude of energy propagation poynting vector (i.e., energy flowing per second per unit area) on the surface of sun:- $$6.17\times { 10 }^{ 10 }W/{ m }^{ 2 }$$
### Units And Measurement Questions and Answers
Units And Measurement Quiz Question Answer
Given $$x = a + b t + c t ^ { 2 }$$ where $$x$$ in metre and $$t$$ in second. Find the dimensional formula of $$b$$
$$L T ^ { - 1 }$$
If L be the inductance, R resistance and C be the capacitance of a capacitor, then dimensional formula of $$\cfrac {L}{R}$$ and RC are $$M^oL^oT, M^oL^oT$$
The dimensions of $$(\mu_{0}\epsilon_{0})^{-\dfrac {1}{2}}$$ are $$[L T^{-1}]$$
If C be the capacitance and V be the electric potential,then the dimensional formula of $$CV^2$$ is $$[ML^2T^{-2} A^o]$$
Given $$x = a + b t + c t ^ { 2 }$$ where $$x$$ in metre and $$t$$ in second. Find the dimensional formula of $$C$$ $$L T ^ { - 2 }$$
Given that m is the mass suspended from a spring force constant k. The dimension of the formula for $$\sqrt{m/k}$$ is same as that for time period
Velocity gradient has dimension of
Frequency
A body of mass $$m_{1}$$, moving with uniform velocity of $$40\ m/s$$ collides with another mass $$m_{2}$$ at rest and then the two together begin to move in a uniform velocity of $$30\ m/s$$. The ratio of their masses $$(m_{1}/m_{2})$$ is $$3.0$$
The dimensions of (force constant \ mass)$$^ { 1 / 2 }$$ are the same as that angular velocity
If area $$(A)$$, velocity $$(v)$$ and density $$(\rho)$$ are base units, then the dimensional formula of force can be represented $$\left [ Av^{2}\rho \right ]$$
### Waves Questions and Answers
Waves Quiz Question Answer
Two sources A and B are sounding notes of frequency 660Hz.A listener move from A to B with a constant velocity u.If the speed of sound is 330m/s ,what must be the value of u so that he hears 8 beats per seconds? $$2 . 8 m/s$$
If two tuning fork side by side are vibrating at $$225$$ and $$257\ Hz$$, then their combined effect would be : that of middle $$C$$
The speed of the wave travelling on the uniform circular hoop of string, rotating clockwise in absence of gravity with tangential speed $$v_0$$, is : $$v=v_0$$
A wave equation which gives the displacement along the Y direction is given by $$y = 10^{-4} sin (60t + 2x)$$ where x and y are in metres and t is time in seconds. This represents a wave of amplitude $$10^{-4}$$ metre
A standing wave arises on a string when two waves of equal amplitude, frequency, and wavelength traveling in opposite directions superimpose. If the frequency of two-component wäves is doubled, then the frequency of oscillation of the standing waves gets doubled
The space density of the potential energy $$PE = E_p(x, t)$$ at a point (x, t) in the space is $$E_p = \dfrac{\rho a^2 \omega^2}{2} sin^2\space kx\space cos^2 \omega t$$
Two sine waves of slightly different frequencies $$f_1$$ and $$f_2 (f_1 > f_2)$$ with zero phase difference, same amplitudes, travelling in the same direction superimpose. A maxima appears at a time $$1/[2(f_1 - f_2)]$$ later (or earlier) than a minima appears.
The equation of a progressive wave is given by $$y=10 sin (5t-x)$$. The wave gets reflected from a open boundary. The equation of the reflected wave is $$y=10 sin (5t+x)$$
A particle performs SHM with amp $$A$$. Its speed is hetled when at $$\dfrac {2A}{3}$$ from equation. Two new amp is $$\dfrac {7A}{3}$$
A small mass executes linear SHM about O with amplitude a and period T. Its displacement from O attime T/8 after passing through O is: $$\dfrac{a}{\sqrt2}$$
### Work, Energy And Power Questions and Answers
Work, Energy And Power Quiz Question Answer
A vibrating body possesses: sound energy
A force $$\vec { F } =\left( { 3x }^{ 2 }+2x-7 \right)$$ N acts on a 2 kg body as a result of which the body gest displaced x=0 to x=5 cm. The work done by the force will be- 115 Joule
A particle moves along the x-axis from x=0 to x=5 m under the influence of a force given by $$F=\left( { 7-2x+3x }^{ 2 } \right) N.$$ The work done in the process is 135 J
A uniform elastic string has length $$a_{1}$$ when tension is $$T_{1}$$ and length $$a_{2}$$ when tension is $$T_{2}$$. The amount of work done in stretching it from its natural length to a length $$(a_{1}+ a_{2})$$ is ? $$\dfrac {1}{2}\dfrac {(a_{1}T_{1}-a_{2}T_{2})^{2}}{2(T_{1}-T_{2})(a_{1}- a_{2})}$$
Velocity-time graph of a particle of mass 2 kg moving in a straight line is as shown in figure. Work done by all the forces on the particle during the motion is:
$$400 J$$
A particle is displaced from a position $$(2\hat { i } -\hat { j } +\hat { k } )$$ metre to another position $$(3\hat { i } +2\hat { j } -2\hat { k } )$$ meter under the action of force $$(2\hat { i } +\hat { j } -\hat { k } )$$ N. Work done by the force is: 8 J
A balloon with its contents weighing 160 N is moving down with an acceleration of g/2 $${ ms }^{ -2 }$$ the mass to be removed from it so that the balloon moves up with an acceleration of g/3$${ ms }^{ -2 }$$ is 10 kg
In $$10 s$$, a body of $$6 kg$$ mass is dragged $$8 m$$ with uniform velocity across a floor by a steady force of $$20 N$$. The K.E of the body is: $$1.92 J$$
A body of mass 5 Kg initially at rest is moved by a horizontal force of 2 N on a smooth horizontal surface. The work done by the force in 10 s is 40 J
A force of $$\left(4 x^{2}+3 x\right)$$ N acts on a particle which displaces it from $$x=2 m$$ to $$x=3 \mathrm{m}$$.
The work done by the force is
$$32.8 J$$
### Medical Physics MCQ Questions for Class 11 - Practice Test with Solutions
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• Keep passing this interesting approach of practicing Plus One CBSE Medical Physics Gravitation MCQ Questions to your co-students and help them in attempting the entrance exams like JEE & NEET. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8143771886825562, "perplexity": 589.2692718613694}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446711121.31/warc/CC-MAIN-20221206225143-20221207015143-00123.warc.gz"} |
https://learnzillion.com/lesson_plans/3415-8-comparing-unit-size-and-measured-length-c | # 8. Comparing Unit Size and Measured Length (C)
teaches Common Core State Standards CCSS.Math.Content.2.MD.A.1 http://corestandards.org/Math/Content/2/MD/A/1
teaches Common Core State Standards CCSS.Math.Content.2.MD.A.2 http://corestandards.org/Math/Content/2/MD/A/2
teaches Common Core State Standards CCSS.Math.Practice.MP2 http://corestandards.org/Math/Practice/MP2
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Lesson objective: Understand that the size of the unit impacts the number of units in a measured length.
Students bring prior knowledge of measurement from 2.MD.A.1. This prior knowledge is extended to reasoning about the relationship between the unit size and number of units in a measured length as students compare two measured lengths. A conceptual challenge students may encounter is understanding that the relationship is an inverse relationship.
The concept is developed through work with problems evaluating a task or situation in which students explore and analyze different measurement systems and the related units.
This work helps students deepen their understanding of equivalence because the inverse relationship shows that the smaller the measurement unit, the more units are needed in the measured length.
Students engage in Mathematical Practice 2 (Reason abstract and quantitatively) as they reason and make sense of the problems as they compare lengths measured using different units.
Key vocabulary:
• foot
• inch
• inverse
• length
• meter
• meter stick
• relationship
• ruler
• tape measure
• tool
• unit of measure
• yard
• yardstick
Special materials needed:
• centimeter ruler
• inch ruler
• meter stick
• ruler
• tape measure
• yardstick
Related content | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9362915754318237, "perplexity": 6853.571807987064}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-04/segments/1484560280239.54/warc/CC-MAIN-20170116095120-00121-ip-10-171-10-70.ec2.internal.warc.gz"} |
https://hal-univ-avignon.archives-ouvertes.fr/hal-03194569 | # Anosov representations as holonomies of globally hyperbolic spatially compact conformally flat spacetimes
Abstract : Anosov representations were introduced by F. Labourie [18] for fundamental groups of closed negatively curved surfaces, and generalized by O. Guichard and A. Wienhard [19] to representations of arbitrary Gromov hyperbolic groups into real semisimple Lie groups. In this paper, we focus on Anosov representations into the identity component O0(2, n) of O(2, n) for n ≥ 2. Our main result is that any Anosov representation with negative limit set as defined in [8] is the holonomy group of a spatially compact, globally hyperbolic maximal (abbrev. CGHM) conformally flat spacetime. The proof of the spatial compactness needs a particular care. The key idea is to notice that for any spacetime M , the space of lightlike geodesics of M is homeomorphic to the unit tangent bundle of a Cauchy hypersurface of M. For this purpose, we introduce the space of causal geodesics containing timelike and lightlike geodesics of anti-de Sitter space and lightlike geodesics of its conformal boundary: the Einstein spacetime. The spatial compactness is a consequence of the following theorem : Any Anosov representation acts properly discontinuously by isometries on the set of causal geodesics avoiding the limit set; besides, this action is cocompact. It is stated in a general setting by O. Guichard, F. Kassel and A. Wienhard in [11]. We can see this last result as a Lorentzian analogue of the action of convex cocompact Kleinian group on the complementary of the limit set in H n. Lastly, we show that the conformally flat spacetime in our main result is the union of two conformal copies of a strongly causal AdS-spacetime with boundary which contains-when the limit set is not a topological (n − 1)-sphere-a globally hyperbolic region having the properties of a black hole as defined in [2], [3], [4].
Document type :
Preprints, Working Papers, ...
Domain :
https://hal-univ-avignon.archives-ouvertes.fr/hal-03194569
Contributor : Rym Smai <>
Submitted on : Monday, April 12, 2021 - 9:57:38 PM
Last modification on : Wednesday, April 14, 2021 - 3:02:53 AM
Long-term archiving on: : Tuesday, July 13, 2021 - 6:08:36 PM
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Anosov representations and Bla...
Files produced by the author(s)
### Identifiers
• HAL Id : hal-03194569, version 1
• ARXIV : 2104.06021
### Citation
Rym Smai. Anosov representations as holonomies of globally hyperbolic spatially compact conformally flat spacetimes. 2021. ⟨hal-03194569⟩
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https://stats.stackexchange.com/questions/52829/why-is-a-likelihood-ratio-test-distributed-chi-squared | Why is a likelihood-ratio test distributed chi-squared?
Why is the test statistic of a likelihood ratio test distributed chi-squared?
$2(\ln \text{ L}_{\rm alt\ model} - \ln \text{ L}_{\rm null\ model} ) \sim \chi^{2}_{df_{\rm alt}-df_{\rm null}}$
• – Nick Sabbe Mar 20 '13 at 16:09
• Thanks for the reference. Here's one from me: stats.stackexchange.com/faq#etiquette – Dr. Beeblebrox Mar 20 '13 at 16:50
• Notice the "Bring your sense of humour" there. I did not intend to be rude, but the answer to this question would be relatively tedious and consist, basically, of the contents of that article (or some of the better statistics textbooks). If you state your precise problem with the explanation in one of these, I shall be glad to help you. – Nick Sabbe Mar 20 '13 at 17:17
• Direct link to Wilks' original paper with no paywall. – ayorgo Aug 25 '19 at 14:49
As mentioned by @Nick this is a consequence of Wilks' theorem. But note that the test statistic is asymptotically $\chi^2$-distributed, not $\chi^2$-distributed.
I am very impressed by this theorem because it holds in a very wide context. Consider a statistical model with likelihood $l(\theta \mid y)$ where $y$ is the vector observations of $n$ independent replicated observations from a distribution with parameter $\theta$ belonging to a submanifold $B_1$ of $\mathbb{R}^d$ with dimension $\dim(B_1)=s$. Let $B_0 \subset B_1$ be a submanifold with dimension $\dim(B_0)=m$. Imagine you are interested in testing $H_0\colon\{\theta \in B_0\}$.
The likelihood ratio is $$lr(y) = \frac{\sup_{\theta \in B_1}l(\theta \mid y)}{\sup_{\theta \in B_0}l(\theta \mid y)}.$$ Define the deviance $d(y)=2 \log \big(lr(y)\big)$. Then Wilks' theorem says that, under usual regularity assumptions, $d(y)$ is asymptotically $\chi^2$-distributed with $s-m$ degrees of freedom when $H_0$ holds true.
It is proven in Wilk's original paper mentioned by @Nick. I think this paper is not easy to read. Wilks published a book later, perhaps with an easiest presentation of his theorem. A short heuristic proof is given in Williams' excellent book.
• Sad that this theorem is not mentioned in the wikipedia page devoted to Samuel S. Wilks – Stéphane Laurent Mar 20 '13 at 17:33
• Oh come on Stephane. This is Wikipedia, you can edit it and improve it! – StasK Mar 20 '13 at 19:19
• @StasK I know that but I have never tried. And I already spend too much time of my life with statistics & mathematics ;) – Stéphane Laurent Mar 20 '13 at 19:23
• Is there an intuition for why the 2 is in front of the log in the definition of the deviance? – user56834 Feb 13 '18 at 18:58
• @Programmer2134 It is derived from a second order taylor expansion. – Frank Vel Sep 19 '18 at 12:50
I second Nick Sabbe's harsh comment, and my short answer is, It is not. I mean, it only is in the normal linear model. For absolutely any other sort of circumstances, the exact distribution is not a $\chi^2$. In many situations, you can hope that Wilks' theorem conditions are satisfied, and then asymptotically the log-likelihood ratio test statistics converges in distribution to $\chi^2$. Limitations and violations of the conditions of Wilks' theorem are too numerous to disregard.
1. The theorem assumes i.i.d. data $\Rightarrow$ expect issues with dependent data, such as time series or unequal probability survey samples (for which the likelihoods are poorly defined, anyway; the "regular" $\chi^2$ tests, such as independence tests in contingency tables, start behaving as a sum $\sum_k a_k v_k, v_k \sim \mbox{i.i.d.} \chi^2_1$ (Rao & Scott). For i.i.d. data, $a_k=1$, and the sum becomes the $\chi^2$. But for non-independent data, this is no longer the case.
2. The theorem assumes the true parameter to be in the interior of the parameter space. If you have a Euclidean space to work with, that's not an issue. However, in some problems, the natural restrictions may arise, such as variance $\ge$ 0 or correlation between -1 and 1. If the true parameter is one the boundary, then the asymptotic distribution is a mixture of $\chi^2$ with different degrees of freedom, in the sense that the cdf of the test is the sum of such cdfs (Andrews 2001, plus two or three more of his papers from the same period, with history going back to Chernoff 1954).
3. The theorem assumes that all the relevant derivatives are non-zero. This can be challenged with some nonlinear problems and/or parameterizations, and/or situations when a parameter is not identified under the null. Suppose you have a Gaussian mixture model, and your null is one component $N(\mu_0,\sigma^2_0)$ vs. the alternative of two distinct components $f N(\mu_1,\sigma_1^2) + (1-f) N(\mu_2,\sigma_2^2)$ with a mixing fraction $f$. The null is apparently nested in the alternative, but this can be expressed in a variety of ways: as $f=0$ (in which case the parameters $\mu_1,\sigma_1^2$ are not identified), $f=1$ (in which case $\mu_2, \sigma_2^2$ are not identified), or $\mu_1=\mu_2, \sigma_1=\sigma_2$ (in which case $f$ is not identified). Here, you can't even say how many degrees of freedom your test should have, as you have different number of restrictions depending on how you parameterize the nesting. See the work of Jiahua Chen on this, e.g. CJS 2001.
4. The $\chi^2$ may work OK if the distribution has been correctly specified. But if it was not, the test will break down again. In the (largely neglected by statisticians) subarea of multivariate analysis known as structural equation covariance modeling, a multivariate normal distribution is often assumed, but even if the structure is correct, the test will misbehave if the distribution is different. Satorra and Bentler 1995 show that the distribution will become $\sum_k a_k v_k, v_k \sim \mbox{i.i.d.} \chi^2_1$, the same story as with non-independent data in my point 1, but they've also demonstrated how the $a_k$s depend on the structure of the model and the fourth moments of the distribution.
5. For finite samples, in a large class of situations likelihood ratio is Bartlett-correctible: while ${\rm Prob}[d(y) \le x]=F(x;\chi^2_d)[1+O(n^{-1})]$ for a sample of size $n$, and $F(x;\chi^2_d)$ being the distribution function of the $\chi^2_d$ distribution, for the regular likelihood problems you can find a constant $b$ such that ${\rm Prob}[d(y)/(1+b/n) \le x]=F(x;\chi^2_d)[1+O(n^{-2})]$, i.e., to a higher order of accuracy. So the $\chi^2$ approximation for finite samples can be improved (and arguably should be improved if you know how). The constant $b$ depends on the structure of the model, and sometimes on the auxiliary parameters, but if it can be consistently estimated, that works, too, in improving the order of coverage.
For a review of these and similar esoteric issues in likelihood inference, see Smith 1989.
• Thanks! Very instructive. What do you mean by "it only is in the normal linear model" ? For a Fisher test when $B_0$ and $B_1$ are linear subspaces, then the deviance is a monotone function of the Fisher statistic, and it is only asymptotically $\chi^2$. – Stéphane Laurent Mar 20 '13 at 19:46
• With known variance, I should add. – StasK Mar 20 '13 at 19:51
As other commentators have pointed out, Wilks' theorem (Wilks 1938) only shows that, under various regularity conditions, this statistic is asymptotically chi-squared distributed. The asymptotic result follows from taking a multivariate Taylor expansion of the log-likelihood function and looking at what happens when the MLE is a critical point of the function. Using various asymptotic results relating to the MLE it is possible to eliminate all terms in the expansion except for the second-order term, which turns asymptotically into the squared norm of a normal random vector.
Derivations of Wilks' theorem can be found in various textbooks on estimation theory, and there are also versions floating around in online statistics lecture notes (see e.g., here). The general derivation requires a knowledge of mutivariate Taylor series and results pertaining to the MLE of a vector parameter. A simpler version of the derivation can be shown in the scalar case where the alternative model has only one more (scalar) parameter than the null model. For illustrative purposes, I will show the heuristic derivation of the result in this case.
Heuristic demonstration of Wilks' theorem with one degree-of-freedom: Consider the simple case where we have an alternative hypothesis with only one scalar parameter $$\theta$$ that is fixed to the value $$\theta_0$$ under the null hypothesis. In this case we have $${df}_A - {df}_0 = 1$$ so the asymptotic distribution is a chi-squared distribution with one degree-of-freedom. To derive this asymptotic distribution we will use the following Taylor expansion:
$$\ell_\mathbf{x}(\theta_0) = \ell_\mathbf{x}(\hat{\theta}_n) + \ell_\mathbf{x}'(\hat{\theta}_n) (\theta_0 - \hat{\theta}_n) + \frac{\ell_\mathbf{x}''(\hat{\theta}_n)}{2} (\theta_0 - \hat{\theta}_n)^2 + \mathcal{O}((\theta_0 - \hat{\theta}_n)^3).$$
To facilitate our analysis, we define the standardised estimation error $$E_n(\theta) \equiv (\theta - \hat{\theta}_n) \sqrt{n\mathcal{I}(\theta)}$$ where $$\mathcal{I}$$ is the Fisher information function. Now, suppose that the MLE $$\hat{\theta}_n$$ occurs at a critical point of the log-likelihood function so that $$\ell_\mathbf{x}'(\hat{\theta}_n) = 0$$. This gives the following simplified form for the Taylor expansion:
\begin{aligned} \ell_\mathbf{x}(\theta_0) &= \ell_\mathbf{x}(\hat{\theta}_n) + \frac{\ell_\mathbf{x}''(\hat{\theta}_n)}{2} (\theta_0 - \hat{\theta}_n)^2 + \mathcal{O}((\theta_0 - \hat{\theta}_n)^3) \\[6pt] &= \ell_\mathbf{x}(\hat{\theta}_n) + \frac{\ell_\mathbf{x}''(\hat{\theta}_n)}{2 n \mathcal{I}(\theta_0)} \cdot E_n(\theta_0)^2 + \mathcal{O} \bigg( \frac{E_n(\theta_0)^3}{n^{3/2}} \bigg). \\[6pt] \end{aligned}
Substituting this expansion into the likelihood-ratio statistic we get:
\begin{aligned} W_n &\equiv 2(\ell_\mathbf{x}(\hat{\theta}_n) - \ell_\mathbf{x}(\theta_0)) \\[6pt] &= - \frac{\ell_\mathbf{x}''(\hat{\theta}_n)}{n \mathcal{I}(\theta_0)} \cdot E_n(\theta_0)^2 + \mathcal{O} \bigg( \frac{E_n(\theta_0)^3}{n^{3/2}} \bigg). \\[6pt] \end{aligned}
Now, suppose you are looking at the distribution of $$W_n$$ under the null hypothesis that $$\theta = \theta_0$$. Under some regularity conditions, it is known that we get the asymptotic distribution $$E_n(\theta_0) \sim \text{N}(0, 1)$$ and we also get the limiting result $$\ell_\mathbf{x}''(\hat{\theta}_n)/n \rightarrow -\mathcal{I}(\theta_0)$$. This means that the order term in the above expansion will vanish asymptotically, and so we have the asymptotic result:
\begin{aligned} W_n \rightarrow E_n(\theta_0)^2 \sim \chi_{1}^2. \\[6pt] \end{aligned}
This is the chi-squared asymptotic result that holds in the case where the alternative model has only one more degree-of-freedom than the null model. The more general derivation is essentially the same, but it involves use of a multivariate parameter vector, which means we use the multivariate Taylor series and the properties of the MLE for a vector parameter.
As others have noted, Wilks' theorem uses a number of regularity conditions, and these conditions do not always hold. The result assumes that the MLE occurs at an interior point of the parameter space which is a critical point of the log-likelihood function. Additionally, it assumes all the required conditions for the standard asymptotic normality results for the MLE. Even when these various regularity conditions hold (which actually happens in quite a broad range of cases), the result is only an asymptotic result, and so it might not be a particularly good approximation for small sample sizes. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 15, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9588682651519775, "perplexity": 394.1623805802779}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610703496947.2/warc/CC-MAIN-20210115194851-20210115224851-00333.warc.gz"} |
https://tutorial.math.lamar.edu/Classes/Alg/LinearApps.aspx | Paul's Online Notes
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### Section 2-3 : Applications of Linear Equations
We now need to discuss the section that most students hate. We need to talk about applications to linear equations. Or, put in other words, we will now start looking at story problems or word problems. Throughout history students have hated these. It is my belief however that the main reason for this is that students really don’t know how to work them. Once you understand how to work them, you’ll probably find that they aren’t as bad as they may seem on occasion. So, we’ll start this section off with a process for working applications.
#### Process for Working Story/Word Problems
2. READ THE PROBLEM AGAIN. Okay, this may be a little bit of overkill here. However, the point of these first two steps is that you must read the problem. This step is the MOST important step, but it is also the step that most people don’t do properly.
You need to read the problem very carefully and as many times as it takes. You are only done with this step when you have completely understood what the problem is asking you to do. This includes identifying all the given information and identifying what you are being asked to find.
Again, it can’t be stressed enough that you’ve got to carefully read the problem. Sometimes a single word can completely change how the problem is worked. If you just skim the problem you may well miss that very important word.
3. Represent one of the unknown quantities with a variable and try to relate all the other unknown quantities (if there are any of course) to this variable.
4. If applicable, sketch a figure illustrating the situation. This may seem like a silly step, but it can be incredibly helpful with the next step on occasion.
5. Form an equation that will relate known quantities to the unknown quantities. To do this make use of known formulas and often the figure sketched in the previous step can be used to determine the equation.
6. Solve the equation formed in the previous step and write down the answer to all the questions. It is important to answer all the questions that you were asked. Often you will be asked for several quantities in the answer and the equation will only give one of them.
7. Check your answer. Do this by plugging into the equation, but also use intuition to make sure that the answer makes sense. Mistakes can often be identified by acknowledging that the answer just doesn’t make sense.
Let’s start things off with a couple of fairly basic examples to illustrate the process. Note as well that at this point it is assumed that you are capable of solving fairly simple linear equations and so not a lot of detail will be given for the actual solution stage. The point of this section is more on the set up of the equation than the solving of the equation.
Example 1 In a certain Algebra class there is a total of 350 possible points. These points come from 5 homework sets that are worth 10 points each and 3 hour exams that are worth 100 points each. A student has received homework scores of 4, 8, 7, 7, and 9 and the first two exam scores are 78 and 83. Assuming that grades are assigned according to the standard scale and there are no weights assigned to any of the grades is it possible for the student to receive an A in the class and if so what is the minimum score on the third exam that will give an A? What about a B?
Show Solution
Okay, let’s start off by defining $$p$$ to be the minimum required score on the third exam.
Now, let’s recall how grades are set. Since there are no weights or anything on the grades, the grade will be set by first computing the following percentage.
$\frac{{{\mbox{actual points}}}}{{{\mbox{total possible points}}}} = {\mbox{ grade percentage}}$
Since we are using the standard scale if the grade percentage is 0.9 or higher the student will get an A. Likewise, if the grade percentage is between 0.8 and 0.9 the student will get a B.
We know that the total possible points is 350 and the student has a total points (including the third exam) of,
$4 + 8 + 7 + 7 + 9 + 78 + 83 + p = 196 + p$
The smallest possible percentage for an A is 0.9 and so if $$p$$ is the minimum required score on the third exam for an A we will have the following equation.
$\frac{{196 + p}}{{350}} = 0.9$
This is a linear equation that we will need to solve for $$p$$.
$196 + p = 0.9\left( {350} \right) = 315\hspace{0.25in}\,\,\,\, \Rightarrow \hspace{0.25in}\,\,\,p = 315 - 196 = 119$
So, the minimum required score on the third exam is 119. This is a problem since the exam is worth only 100 points. In other words, the student will not be getting an A in the Algebra class.
Now let’s check if the student will get a B. In this case the minimum percentage is 0.8. So, to find the minimum required score on the third exam for a B we will need to solve,
$\frac{{196 + p}}{{350}} = 0.8$
Solving this for $$p$$ gives,
$196 + p = 0.8\left( {350} \right) = 280\hspace{0.25in}\,\,\,\, \Rightarrow \hspace{0.25in}\,\,\,p = 280 - 196 = 84$
So, it is possible for the student to get a B in the class. All that the student will need to do is get at least an 84 on the third exam.
Example 2 We want to build a set of shelves. The width of the set of shelves needs to be 4 times the height of the set of shelves and the set of shelves must have three shelves in it. If there are 72 feet of wood to use to build the set of shelves what should the dimensions of the set of shelves be?
Show Solution
We will first define $$x$$ to be the height of the set of shelves. This means that 4$$x$$ is width of the set of shelves. In this case we definitely need to sketch a figure so we can correctly set up the equation. Here it is,
Now we know that there are 72 feet of wood to be used and we will assume that all of it will be used. So, we can set up the following word equation.
$\left( \begin{array}{c}{\mbox{length of }}\\ {\mbox{vertical pieces}}\end{array} \right) + \left( \begin{array}{c}{\mbox{length of }}\\ {\mbox{horizontal pieces}}\end{array} \right) = 72$
It is often a good idea to first put the equation in words before actually writing down the equation as we did here. At this point, we can see from the figure there are two vertical pieces; each one has a length of $$x$$. Also, there are 4 horizontal pieces, each with a length of 4$$x$$. So, the equation is then,
\begin{align*}4\left( {4x} \right) + 2\left( x \right) & = 72\\ 16x + 2x & = 72\\ 18x & = 72\\ x & = 4\end{align*}
So, it looks like the height of the set of shelves should be 4 feet. Note however that we haven’t actually answered the question however. The problem asked us to find the dimensions. This means that we also need the width of the set of shelves. The width is 4(4)=16 feet. So the dimensions will need to be 4x16 feet.
#### Pricing Problems
The next couple of problems deal with some basic principles of pricing.
Example 3 A calculator has been marked up 15% and is being sold for $78.50. How much did the store pay the manufacturer of the calculator? Show Solution First, let’s define $$p$$ to be the cost that the store paid for the calculator. The stores markup on the calculator is 15%. This means that 0.15$$p$$ has been added on to the original price ($$p$$) to get the amount the calculator is being sold for. In other words, we have the following equation $p + 0.15p = 78.50$ that we need to solve for $$p$$. Doing this gives, $1.15p = 78.50\hspace{0.5in} \Rightarrow \hspace{0.5in}p = \frac{{78.50}}{{1.15}} = 68.26087$ The store paid$68.26 for the calculator. Note that since we are dealing with money we rounded the answer down to two decimal places.
Example 4 A shirt is on sale for 15.00 and has been marked down 35%. How much was the shirt being sold for before the sale? Show Solution This problem is pretty much the opposite of the previous example. Let’s start with defining $$p$$ to be the price of the shirt before the sale. It has been marked down by 35%. This means that 0.35$$p$$ has been subtracted off from the original price. Therefore, the equation (and solution) is, \begin{align*}p - 0.35p & = 15.00\\ 0.65p & = 15.00\\ p & = \frac{{15.00}}{{0.65}} = 23.0769\end{align*} So, with rounding it looks like the shirt was originally sold for23.08.
#### Distance/Rate Problems
These are some of the standard problems that most people think about when they think about Algebra word problems. The standard formula that we will be using here is
${\mbox{Distance}} = {\mbox{Rate }} \times {\mbox{ Time}}$
All of the problems that we’ll be doing in this set of examples will use this to one degree or another and often more than once as we will see.
Example 5 Two cars are 500 miles apart and moving directly towards each other. One car is moving at a speed of 100 mph and the other is moving at 70 mph. Assuming that the cars start moving at the same time how long does it take for the two cars to meet?
Show Solution
Let’s let $$t$$ represent the amount of time that the cars are traveling before they meet. Now, we need to sketch a figure for this one. This figure will help us to write down the equation that we’ll need to solve.
From this figure we can see that the Distance Car A travels plus the Distance Car B travels must equal the total distance separating the two cars, 500 miles.
Here is the word equation for this problem in two separate forms.
$\begin{array}{c} \left( \begin{array}{c}{\mbox{Distance}}\\ {\mbox{of Car A}}\end{array} \right) + \left( \begin{array}{c}{\mbox{Distance}}\\ {\mbox{of Car B}}\end{array} \right) = 500\\ \\ \left( \begin{array}{c}{\mbox{Rate of}}\\ {\mbox{ Car A}}\end{array} \right)\left( \begin{array}{c}{\mbox{Time of}}\\ {\mbox{ Car A}}\end{array}\right) + \left( \begin{array}{c}{\mbox{Rate of}}\\ {\mbox{ Car B}}\end{array} \right)\left( \begin{array}{c}{\mbox{Time of}}\\ {\mbox{ Car B}}\end{array} \right) = 500 \end{array}$
We used the standard formula here twice, once for each car. We know that the distance a car travels is the rate of the car times the time traveled by the car. In this case we know that Car A travels at 100 mph for $$t$$ hours and that Car B travels at 70 mph for $$t$$ hours as well. Plugging these into the word equation and solving gives us,
\begin{align*}100t + 70t & = 500\\ 170t & = 500\\ t & = \frac{{500}}{{170}} = 2.941176{\mbox{ hrs}}\end{align*}
So, they will travel for approximately 2.94 hours before meeting.
Example 6 Repeat the previous example except this time assume that the faster car will start 1 hour after slower car starts.
Show Solution
For this problem we are going to need to be careful with the time traveled by each car. Let’s let $$t$$ be the amount of time that the slower travel car travels. Now, since the faster car starts out 1 hour after the slower car it will only travel for $$t - 1$$ hours.
Now, since we are repeating the problem from above the figure and word equation will remain identical and so we won’t bother repeating them here. The only difference is what we substitute for the time traveled for the faster car. Instead of $$t$$ as we used in the previous example we will use $$t - 1$$ since it travels for one hour less that the slower car.
Here is the equation and solution for this example.
\begin{align*}100\left( {t - 1} \right) + 70t & = 500\\ 100t - 100 + 70t & = 500\\ 170t & = 600\\ t & = \frac{{600}}{{170}} = 3.529412{\mbox{ hrs}}\end{align*}
In this case the slower car will travel for 3.53 hours before meeting while the faster car will travel for 2.53 hrs (1 hour less than the slower car...).
Example 7 Two boats start out 100 miles apart and start moving to the right at the same time. The boat on the left is moving at twice the speed as the boat on the right. Five hours after starting the boat on the left catches up with the boat on the right. How fast was each boat moving?
Show Solution
Let’s start off by letting $$r$$ be the speed of the boat on the right (the slower boat). This means that the boat to the left (the faster boat) is moving at a speed of 2$$r$$. Here is the figure for this situation.
From the figure it looks like we’ve got the following word equation.
$100 + \left( \begin{array}{c}{\mbox{Distance}}\\ {\mbox{of Boat B}}\end{array} \right) = \left( \begin{array}{c}{\mbox{Distance}}\\ {\mbox{of Boat A}}\end{array} \right)$
Upon plugging in the standard formula for the distance gives,
$100 + \left( \begin{array}{c}{\mbox{Rate of}}\\ {\mbox{ Boat B}}\end{array} \right)\left( \begin{array}{c}{\mbox{Time of}}\\ {\mbox{ Boat B}}\end{array} \right) = \left( \begin{array}{c}{\mbox{Rate of}}\\ {\mbox{ Boat A}}\end{array} \right)\left( \begin{array}{c}{\mbox{Time of}}\\ {\mbox{ Boat A}}\end{array} \right)$
For this problem we know that the time each is 5 hours and we know that the rate of Boat A is 2$$r$$ and the rate of Boat B is $$r$$. Plugging these into the work equation and solving gives,
\begin{align*}100 + \left( r \right)\left( 5 \right) & = \left( {2r} \right)\left( 5 \right)\\ 100 + 5r & = 10r\\ 100 & = 5r\\ 20 & = r\end{align*}
So, the slower boat is moving at 20 mph and the faster boat is moving at 40 mph (twice as fast).
#### Work/Rate Problems
These problems are actually variants of the Distance/Rate problems that we just got done working. The standard equation that will be needed for these problems is,
$\left( \begin{array}{c}{\mbox{Portion of job }}\\ {\mbox{done in given time}}\end{array} \right) = \left( \begin{array}{c}{\mbox{Work}}\\ {\mbox{Rate}}\end{array} \right) \times \left( \begin{array}{c}{\mbox{Time Spent}}\\ {\mbox{Working}}\end{array} \right)$
As you can see this formula is very similar to the formula we used above.
Example 8 An office has two envelope stuffing machines. Machine A can stuff a batch of envelopes in 5 hours, while Machine B can stuff a batch of envelopes in 3 hours. How long would it take the two machines working together to stuff a batch of envelopes?
Show Solution
Let $$t$$ be the time that it takes both machines, working together, to stuff a batch of envelopes. The word equation for this problem is,
$\begin{array}{c}\left( \begin{array}{c}{\mbox{Portion of job }}\\ {\mbox{done by Machine A}}\end{array} \right) + \left( \begin{array}{c}{\mbox{Portion of job }}\\ {\mbox{done by Machine B}}\end{array} \right) = 1{\mbox{ Job}}\\ \\ \left( \begin{array}{c}{\mbox{Work Rate}}\\ {\mbox{of Machine A}}\end{array} \right)\left( \begin{array}{c}{\mbox{Time Spent}}\\ {\mbox{Working}}\end{array} \right) + \left( \begin{array}{c}{\mbox{Work Rate}}\\ {\mbox{of Machine B}}\end{array} \right)\left( \begin{array}{c}{\mbox{Time Spent}}\\ {\mbox{Working}}\end{array} \right) = 1\end{array}$
We know that the time spent working is $$t$$ however we don’t know the work rate of each machine. To get these we’ll need to use the initial information given about how long it takes each machine to do the job individually. We can use the following equation to get these rates.
$1{\mbox{ Job}} = \left( \begin{array}{c}{\mbox{Work}}\\ {\mbox{Rate}}\end{array} \right) \times \left( \begin{array}{c}{\mbox{Time Spent}}\\ {\mbox{Working}}\end{array} \right)$
$1{\mbox{ Job}} = \left( {{\mbox{Work Rate of A}}} \right) \times \left( 5 \right)\hspace{0.25in} \Rightarrow \hspace{0.25in}{\mbox{Work Rate of A}} = \frac{1}{5}$
Now, Machine B.
$1{\mbox{ Job}} = \left( {{\mbox{Work Rate of B}}} \right) \times \left( 3 \right)\hspace{0.25in} \Rightarrow \hspace{0.25in}{\mbox{Work Rate of B}} = \frac{1}{3}$
Plugging these quantities into the main equation above gives the following equation that we need to solve.
\begin{align*}\frac{1}{5}t + \frac{1}{3}t & = 1\hspace{0.5in}{\mbox{Multiplying both sides by 15}}\\ 3t + 5t & = 15\\ 8t & = 15\\ t & = \frac{{15}}{8} = 1.875{\mbox{ hours}}\end{align*}
So, it looks like it will take the two machines, working together, 1.875 hours to stuff a batch of envelopes.
Example 9 Mary can clean an office complex in 5 hours. Working together John and Mary can clean the office complex in 3.5 hours. How long would it take John to clean the office complex by himself?
Show Solution
Let $$t$$ be the amount of time it would take John to clean the office complex by himself. The basic word equation for this problem is,
$\begin{array}{c}\left( \begin{array}{c}{\mbox{Portion of job }}\\ {\mbox{done by Mary}}\end{array} \right) + \left( \begin{array}{c}{\mbox{Portion of job }}\\ {\mbox{done by John}}\end{array} \right) = 1{\mbox{ Job}}\\ \\ \left( \begin{array}{c}{\mbox{Work Rate}}\\ {\mbox{of Mary}}\end{array} \right)\left( \begin{array}{c}{\mbox{Time Spent}}\\ {\mbox{Working}}\end{array} \right) + \left( \begin{array}{c}{\mbox{Work Rate}}\\ {\mbox{of John}}\end{array} \right)\left( \begin{array}{c}{\mbox{Time Spent}}\\ {\mbox{Working}}\end{array} \right) = 1\end{array}$
This time we know that the time spent working together is 3.5 hours. We now need to find the work rates for each person. We’ll start with Mary.
$1{\mbox{ Job}} = \left( {{\mbox{Work Rate of Mary}}} \right) \times \left( 5 \right)\hspace{0.25in} \Rightarrow \hspace{0.25in}{\mbox{Work Rate of Mary}} = \frac{1}{5}$
Now we’ll find the work rate of John. Notice however, that since we don’t know how long it will take him to do the job by himself we aren’t going to be able to get a single number for this. That is not a problem as we’ll see in a second.
$1{\mbox{ Job}} = \left( {{\mbox{Work Rate of John}}} \right) \times \left( t \right)\hspace{0.25in} \Rightarrow \hspace{0.25in}{\mbox{Work Rate of John}} = \frac{1}{t}$
Notice that we’ve managed to get the work rate of John in terms of the time it would take him to do the job himself. This means that once we solve the equation above we’ll have the answer that we want. So, let’s plug into the work equation and solve for the time it would take John to do the job by himself.
\begin{align*}\frac{1}{5}\left( {3.5} \right) + \frac{1}{t}\left( {3.5} \right) & = 1\hspace{0.5in}{\mbox{Multiplying both sides by }}5t\\ 3.5t + \left( {3.5} \right)\left( 5 \right) & = 5t\\ 17.5 & = 1.5t\\ \frac{{17.5}}{{1.5}} & = t\hspace{0.5in} \Rightarrow \hspace{0.5in}t = 11.67{\mbox{ hrs}}\end{align*}
So, it looks like it would take John 11.67 hours to clean the complex by himself.
#### Mixing Problems
This is the final type of problems that we’ll be looking at in this section. We are going to be looking at mixing solutions of different percentages to get a new percentage. The solution will consist of a secondary liquid mixed in with water. The secondary liquid can be alcohol or acid for instance.
The standard equation that we’ll use here will be the following.
$\left( \begin{array}{c}{\mbox{Amount of secondary}}\\ {\mbox{liquid in the water}}\end{array} \right) = \left( \begin{array}{c}{\mbox{Percentage of}}\\ {\mbox{Solution}}\end{array} \right) \times \left( \begin{array}{c}{\mbox{Volume of}}\\ {\mbox{Solution}}\end{array} \right)$
Note as well that the percentage needs to be a decimal. So if we have an 80% solution we will need to use 0.80.
Example 10 How much of a 50% alcohol solution should we mix with 10 gallons of a 35% solution to get a 40% solution?
Show Solution
Okay, let $$x$$ be the amount of 50% solution that we need. This means that there will be $$x + 10$$ gallons of the 40% solution once we’re done mixing the two.
Here is the basic work equation for this problem.
$\begin{array}{c}\left( \begin{array}{c}{\mbox{Amount of alcohol}}\\ {\mbox{in 50% Solution}}\end{array} \right) + \left( \begin{array}{c}{\mbox{Amount of alcohol}}\\ {\mbox{in 35% Solution}}\end{array} \right) = \left( \begin{array}{c}{\mbox{Amount of alcohol}}\\ {\mbox{in 40% Solution}}\end{array} \right)\\ \\ \left( {0.5} \right)\left( \begin{array}{c}{\mbox{Volume of }}\\ {\mbox{50% Solution}}\end{array} \right) + \left( {0.35} \right)\left( \begin{array}{c}{\mbox{Volume of }}\\ {\mbox{35% Solution}}\end{array} \right) = \left( {0.4} \right)\left( \begin{array}{c}{\mbox{Volume of }}\\ {\mbox{40% Solution}}\end{array} \right)\end{array}$
Now, plug in the volumes and solve for $$x$$.
\begin{align*}0.5x + 0.35\left( {10} \right) & = 0.4\left( {x + 10} \right)\\ 0.5x + 3.5 & = 0.4x + 4\\ 0.1x & = 0.5\\ x & = \frac{{0.5}}{{0.1}} = 5\,{\mbox{gallons}}\end{align*}
So, we need 5 gallons of the 50% solution to get a 40% solution.
Example 11 We have a 40% acid solution and we want 75 liters of a 15% acid solution. How much water should we put into the 40% solution to do this?
Show Solution
Let $$x$$ be the amount of water we need to add to the 40% solution. Now, we also don’t how much of the 40% solution we’ll need. However, since we know the final volume (75 liters) we will know that we will need $$75 - x$$ liters of the 40% solution.
Here is the word equation for this problem.
$\left( \begin{array}{c}{\mbox{Amount of acid}}\\ {\mbox{in the water}}\end{array} \right) + \left( \begin{array}{c}{\mbox{Amount of acid}}\\ {\mbox{in 40% Solution}}\end{array} \right) = \left( \begin{array}{c}{\mbox{Amount of acid}}\\ {\mbox{in 15% Solution}}\end{array} \right)$
Notice that in the first term we used the “Amount of acid in the water”. This might look a little weird to you because there shouldn’t be any acid in the water. However, this is exactly what we want. The basic equation tells us to look at how much of the secondary liquid is in the water. So, this is the correct wording. When we plug in the percentages and volumes we will think of the water as a 0% percent solution since that is in fact what it is. So, the new word equation is,
$\left( 0 \right)\left( \begin{array}{c}{\mbox{Volume }}\\ {\mbox{of Water}}\end{array} \right) + \left( {0.4} \right)\left( \begin{array}{c}{\mbox{Volume of }}\\ {\mbox{40% Solution}}\end{array} \right) = \left( {0.15} \right)\left( \begin{array}{c}{\mbox{Volume of }}\\ {\mbox{15% Solution}}\end{array} \right)$
Do not get excited about the zero in the first term. This is okay and will not be a problem. Let’s now plug in the volumes and solve for $$x$$.
\begin{align*}\left( 0 \right)\left( x \right) + \left( {0.4} \right)\left( {75 - x} \right) & = \left( {0.15} \right)\left( {75} \right)\\ 30 - 0.4x & = 11.25\\ 18.75 & = 0.4x\\ x & = \frac{{18.75}}{{0.4}} = 46.875{\mbox{ liters}}\end{align*}
So, we need to add in 46.875 liters of water to 28.125 liters of a 40% solution to get 75 liters of a 15% solution. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 2, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8414506912231445, "perplexity": 357.58485586883734}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593657140337.79/warc/CC-MAIN-20200712211314-20200713001314-00481.warc.gz"} |
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• Large-time behavior of the spherically symmetric compressible
Navier–Stokes equations with degenerate viscosity coefficients
• Abstract: This paper is concerned with the vacuum free boundary problem for the compressible spherically symmetric Navier–Stokes equations with an external force and degenerate viscosities in $$\mathbb {R}^{n}(n\ge 2)$$ . When the initial data are a small perturbation of the stationary profile and the viscosity coefficients are proportional to $$\rho ^{\theta }$$ with $$\theta \in {\left\{ \begin{array}{ll} (0,2(\gamma -1))\cap (0,\frac{\gamma }{2}]&{}n=2\\ (0,\frac{\gamma }{2}]&{}n\ge 3 \end{array}\right. }$$ , a result on the global existence as well as sharper time decay rates of the weak solution is obtained which improves the one in Wei et al. (SIAM J Math Anal 40:869–904, 2008). The proof is based on some weighted energy estimates, and in our analysis, no smallness constraint is prescribed upon the derivatives of the initial data. It is also worth pointing out that our result covers the interesting case of the Saint-Venant shallow water model (i.e., $$\gamma =2$$ and $$\theta =1$$ ).
PubDate: 2019-03-12
DOI: 10.1007/s00033-019-1101-7
• On instability of standing waves for the mass-supercritical fractional
nonlinear Schrödinger equation
• Abstract: We consider the focusing $$L^2$$ -supercritical fractional nonlinear Schrödinger equation \begin{aligned} i\partial _t u - (-\varDelta )^s u = - u ^\alpha u, \quad (t,x) \in \mathbb {R}^+ \times \mathbb {R}^d, \end{aligned} where $$d\ge 2, \frac{d}{2d-1} \le s <1$$ and $$\frac{4s}{d}<\alpha <\frac{4s}{d-2s}$$ . By means of the localized virial estimate, we prove that the ground-state standing wave is strongly unstable by blowup. This result is a complement to a recent result of Peng–Shi (J Math Phys 59:011508, 2018) where the stability and instability of standing waves were studied in the $$L^2$$ -subcritical and $$L^2$$ -critical cases.
PubDate: 2019-03-11
DOI: 10.1007/s00033-019-1104-4
• Global existence and blowup for a coupled parabolic system with
time-weighted sources on a general domain
• Abstract: We consider the parabolic problem $$\mathbf{u}_{t}-\Delta \mathbf{u} = F(t, \mathbf{u})$$ in $$\Omega \times (0,T)$$ with homogeneous Dirichlet boundary conditions. The nonlinear term is given by \begin{aligned} F(t, \mathbf{u})=(f_1(t) u_2^{p_1}, \ldots , f_m(t) u_1^{p_m}), \end{aligned} where $$\mathbf{u}=(u_1, \ldots , u_m)$$ , $$p_i \ge 1$$ , and $$f_i \in C[0,\infty ),$$ for $$i=1,\ldots ,m$$ . The set of initial data is $$\left\{ \mathbf{u}_0=(u_{0,1},\ldots ,u_{0,m}) \in \right. \left. C_0(\Omega )^m; u_{i,0}\ge 0\right\}$$ , where $$\Omega$$ is an arbitrary domain (either bounded or unbounded) with smooth boundary. We determine conditions that guarantee either the global existence or the blowup in finite time of nonnegative solutions. These conditions are given in terms of the asymptotic behavior of $$\Vert \mathbf{S }(t) { \mathbf u}_0\Vert _{L^\infty (\Omega )}$$ , where $$(\mathbf{S }(t){ \mathbf u}_0)_{t\ge 0}$$ is the heat semigroup on $$C_0(\Omega )^m$$ .
PubDate: 2019-03-09
DOI: 10.1007/s00033-019-1103-5
• Boundary stabilization of Bresse systems
• Abstract: We analyze the Bresse system with partial boundary dissipation. Our main result is to prove that these dissipative mechanisms are enough to stabilize exponentially the whole system provided the wave propagation speeds are equal.
PubDate: 2019-03-07
DOI: 10.1007/s00033-019-1102-6
• Finite-time blow-up of classical solutions to the rotating shallow water
system with degenerate viscosity
• Abstract: In this paper, we study the rotating shallow water system with initial data containing vacuum, the viscosity of the system is degenerate, and the Coriolis force, the capillary force and the turbulent drag force from fiction are involved. When a positive mass is surrounding by a bounded vacuum region (isolated mass group), initially, we prove that any classical solutions to the initial-boundary-value problem and periodic problem will blow up in finite time. This shows that the global weak solutions obtained in Bresch and Desjardins (Commun Math Phys 238(1–2):211–223, 2003) cannot be a classical one as long as the initial data admit an isolated mass group. It also shows that compared with the smoothing properties provided by capillarity and drag terms, the degeneracy of viscosity plays a prominent role in the global regularity problem and leads to finite-time singularity of smooth solutions.
PubDate: 2019-03-06
DOI: 10.1007/s00033-019-1093-3
• Analysis of a drift–diffusion model for organic semiconductor
devices
• Abstract: We discuss drift–diffusion models for charge carrier transport in organic semiconductor devices. The crucial feature in organic materials is the energetic disorder due to random alignment of molecules and the hopping transport of carriers between adjacent energetic sites. The former leads to statistical relations with Gauss–Fermi integrals, which describe the occupation of energy levels by electrons and holes. The latter gives rise to complicated mobility models with a strongly nonlinear dependence on temperature, density of carriers, and electric field strength. We present the state-of-the-art modeling of the transport processes and provide a first existence result for the stationary drift–diffusion model taking all of the peculiarities of organic materials into account. The existence proof is based on Schauder’s fixed-point theorem.
PubDate: 2019-03-06
DOI: 10.1007/s00033-019-1089-z
• Infinitely many positive solutions for Kirchhoff equations with competing
coefficients
• Abstract: In this paper, we consider the following Kirchhoff problem \begin{aligned} -\left( a+b\int \limits _{\mathbb R^3} \nabla u ^2\mathrm{d}x\right) \Delta u+V( x )u=Q( x )u^{p},\quad x\in \mathbb {R}^3, \end{aligned} where $$a,b>0$$ , $$1<p<5$$ , V(r) and Q(r) are bounded and positive functions. Assume that V(r) and Q(r) have the following expansions \begin{aligned} V(r)=1+\frac{d_1}{r^m}+O\left( \frac{1}{r^{m+\theta }}\right) ,\quad Q(r)=1+\frac{d_2}{r^n}+O\left( \frac{1}{r^{n+\kappa }}\right) , \end{aligned} as $$r\rightarrow \infty$$ , for some $$d_1>0,d_2\in \mathbb {R}$$ , $$m,n>2$$ and $$\theta ,\kappa >0$$ . Infinitely many nonradial positive solutions are constructed either $$d_2>0$$ and $$m<n$$ or $$d_2<0$$ .
PubDate: 2019-03-05
DOI: 10.1007/s00033-019-1099-x
• Distributed-order fractional constitutive stress–strain relation in
wave propagation modeling
• Abstract: Distributed-order fractional model of viscoelastic body is used to describe wave propagation in an infinite media. Existence and uniqueness of fundamental solution to the generalized Cauchy problem is obtained explicitly. The wave propagation speed is found to be related to the material properties at initial time. The fundamental solutions corresponding to four thermodynamically acceptable classes of linear fractional constitutive models and power-type distributed-order models are also obtained.
PubDate: 2019-03-04
DOI: 10.1007/s00033-019-1097-z
• Large deformations of Timoshenko and Euler beams under distributed load
• Abstract: In this paper, the general equilibrium equations for a geometrically nonlinear version of the Timoshenko beam are derived from the energy functional. The particular case in which the shear and extensional stiffnesses are infinite, which correspond to the inextensible Euler beam model, is studied under a uniformly distributed load. All the global and local minimizers of the variational problem are characterized, and the relative monotonicity and regularity properties are established.
PubDate: 2019-03-04
DOI: 10.1007/s00033-019-1098-y
• Bound state solutions for some non-autonomous asymptotically cubic
Schrödinger–Poisson systems
• Abstract: We are concerned with the following Schrödinger–Poisson systems \begin{aligned} \left\{ \begin{array}{l@{\quad }l} -\Delta u+u+K(x)\phi (x)u=q(x)f(u), &{}\quad x\in {\mathbb {R}}^3, \\ -\Delta \phi =K(x)u^2, &{} \quad x\in {\mathbb {R}}^3, \end{array} \right. \end{aligned} where f is asymptotically cubic, $$\lim _{ x \rightarrow \infty }K(x)=0$$ and $$\lim _{ x \rightarrow \infty }q(x)=q_{\infty }>0$$ . We establish the existence of bound state solutions to this problem by using the method developed in Szulkin and Weth [20, 21].
PubDate: 2019-03-02
DOI: 10.1007/s00033-019-1096-0
• How strongly does diffusion or logistic-type degradation affect existence
of global weak solutions in a chemotaxis–Navier–Stokes system'
• Abstract: This paper considers the chemotaxis–Navier–Stokes system with nonlinear diffusion and logistic-type degradation term \begin{aligned} {\left\{ \begin{array}{ll} n_t + u\cdot \nabla n = \nabla \cdot (D(n)\nabla n) - \nabla \cdot (n \chi (c) \nabla c) + \kappa n - \mu n^\alpha , &{}\quad x\in \Omega ,\ t>0, \\ c_t + u\cdot \nabla c = \Delta c - nf(c), &{}\quad x \in \Omega ,\ t>0, \\ u_t + (u\cdot \nabla )u = \Delta u + \nabla P + n\nabla \Phi + g, \quad \nabla \cdot u = 0, &{}\quad x \in \Omega ,\ t>0, \end{array}\right. } \end{aligned} where $$\Omega \subset \mathbb {R}^3$$ is a bounded smooth domain; $$D \ge 0$$ is a given smooth function such that $$D_1 s^{m-1} \le D(s) \le D_2 s^{m-1}$$ for all $$s\ge 0$$ with some $$D_2 \ge D_1 > 0$$ and some $$m > 0$$ ; $$\chi ,f$$ are given smooth functions satisfying \begin{aligned} { \left( \frac{f}{\chi } \right) ' >0, \quad \left( \frac{f}{\chi } \right) '' \le 0, \quad (\chi f)' \ge 0 \quad \text{ on } \ [0,\infty ); } \end{aligned} $$\kappa \in \mathbb {R},\mu \ge 0,\alpha >1$$ are constants. This paper shows existence of global weak solutions to the above system under the condition that \begin{aligned} m>\frac{2}{3},\quad \mu \ge 0 \quad \text{ and }\quad \alpha >1 \end{aligned} hold or that \begin{aligned} m> 0, \quad \mu>0 \quad \text{ and } \quad \alpha > \frac{4}{3} \end{aligned} hold. This result asserts that “strong” diffusion effect or “strong” logistic damping derives existence of global weak solutions even though the other effect is “weak” and can include previous works (Kurima and Mizukami in Nonlinear Anal Real World Appl, 2018. arXiv:1802.08807 [math.AP]; Lankeit in Math Models Methods Appl Sci 26:2071–2109, 2016; Winkler in Ann Inst H Poincaré Anal Non Linéaire 33:1329–1352, 2016; Zhang and Li in J Differ Equ 259:3730–3754, 2015).
PubDate: 2019-02-21
DOI: 10.1007/s00033-019-1092-4
• Spectral analysis of sheared nanoribbons
• Abstract: We investigate the spectrum of the Dirichlet Laplacian in a unbounded strip subject to a new deformation of “shearing”: the strip is built by translating a segment oriented in a constant direction along an unbounded curve in the plane. We locate the essential spectrum under the hypothesis that the projection of the tangent vector of the curve to the direction of the segment admits a (possibly unbounded) limit at infinity and state sufficient conditions which guarantee the existence of discrete eigenvalues. We justify the optimality of these conditions by establishing a spectral stability in opposite regimes. In particular, Hardy-type inequalities are derived in the regime of repulsive shearing.
PubDate: 2019-02-20
DOI: 10.1007/s00033-019-1090-6
• On thin inclusions in elastic bodies with defects
• Abstract: An equilibrium problem for a 2D elastic body with thin inclusions and defects is analyzed. The presence of defects means that the problem is formulated in a non-smooth domain. The defects are characterized by a positive damage parameter. Nonlinear boundary conditions at the defect faces are imposed to prevent a mutual penetration between the faces. An existence of solutions is proved, and different formulations of the problem are proposed. We study an asymptotics of solutions with respect to the damage parameter and analyze the limit models. Moreover, we study the dependence of the solution on the rigidity parameter of the inclusions. In particular, passages to infinity and to zero of the rigidity parameter are investigated.
PubDate: 2019-02-19
DOI: 10.1007/s00033-019-1091-5
• New realization method for calculating convective heat transfer near the
hypersonic aircraft surface
• Abstract: The feasibility of a realization method for the three-dimensional surface of an aircraft moving with hypersonic velocity is numerically investigated. An approximate mathematical method, which has the same accuracy at much lower computational cost, is used for calculating convective heat transfer over complex geometric shape of a vehicle. Unstructured grids are applied for numerical tests. The hypersonic aircraft computational aerodynamic predictions and comparisons with experimental data are performed.
PubDate: 2019-02-19
DOI: 10.1007/s00033-019-1095-1
• Viscous profiles in models of collective movement with negative
diffusivity
• Abstract: In this paper, we consider an advection–diffusion equation, in one space dimension, whose diffusivity can be negative. Such equations arise in particular in the modeling of vehicular traffic flows or crowds dynamics, where a negative diffusivity simulates aggregation phenomena. We focus on traveling-wave solutions that connect two states whose diffusivity has different signs; under some geometric conditions, we prove the existence, uniqueness (in a suitable class of solutions avoiding plateaus) and sharpness of the corresponding profiles. Such results are then extended to the case of end states where the diffusivity is positive, but it becomes negative in some interval between them. Also the vanishing viscosity limit is considered. At last, we provide and discuss several examples of diffusivities that change sign and show that our conditions are satisfied for a large class of them in correspondence of real data.
PubDate: 2019-02-19
DOI: 10.1007/s00033-019-1094-2
• Analysis of a linear 3D fluid–mesh–shell interaction problem
• Abstract: We study a linear fluid–structure interaction problem between an incompressible, viscous 3D fluid flow, a 2D linearly elastic Koiter shell, and an elastic 1D net of curved rods. This problem is motivated by studying fluid–structure interaction between blood flow through coronary arteries treated with metallic mesh-like devices called stents. The flow is assumed to be laminar, modeled by the time-dependent Stokes equations, and the structure displacement is assumed to be small, modeled by a system of linear Koiter shell equations allowing displacement in all three spatial directions. The fluid and the mesh-supported structure are coupled via the kinematic and dynamic coupling conditions describing continuity of velocity and balance of contact forces. The coupling conditions are evaluated along a linearized fluid–structure interface, which coincides with the fixed fluid domain boundary. No smallness on the structure velocity is assumed. We prove the existence of a weak solution to this linear fluid–composite structure interaction problem. This is the first result in the area of fluid–structure interaction that includes a 1D elastic mesh and takes into account structural displacements in all three spatial directions. Numerical simulations based on the finite element discretization of the coupled FSI problem are presented.
PubDate: 2019-02-18
DOI: 10.1007/s00033-019-1087-1
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9771056175231934, "perplexity": 1245.8040650050011}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-17/segments/1618038066981.0/warc/CC-MAIN-20210416130611-20210416160611-00184.warc.gz"} |
http://mathhelpforum.com/calculus/6811-subsequence.html | ## Subsequence
Let (an) be a bounded sequence. Let sn=sup{ak:k is greater than or equal to n}. Let b=inf{sn}. Show that there exists a subsequence (ank) that converges to b.
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https://www.physicsforums.com/threads/impulse-how-to-figure-out.282442/ | # Impulse how to figure out?
1. Jan 2, 2009
### fumalicious
Hello... new to the forum and not sure where to post, I see a warning everywhere lol Hope I'm not in the wrong spot.
I haven't been in school in well over a decade, but I'm the kind of guy that went out and got math books on my own because I was jonsing to do some math... it's fun for me. But right now I'm just trying to remember the concept of Impulse and how it was calculated and well, it's been a while. (I did search through the forums before posting btw, didn't find my answer)
I remember watching my teacher throw an egg at a sheet and suggesting throwing it at a wall, then pointing out the difference in impact was measured in Impulse... right?
If I wanted to figure out the difference in force, say the egg would feel, hitting wall A and wall B (the sheet)... how would I measure that? Is that even a valid question? I'm confused.. Difference in acceleration during each impact = different amount of time = difference in force... so if I know the distance the egg travels while being absorbed into the sponginess (also knowing it's initial velocity) vs. the other impact (0 since it is an instant impact..), can I find out the force involved?
If that's too vague I can input more... or too complicated it can be simplified lol I just want to "get it" again and be able to figure out different scenerios if you see what I'm getting at...
Thanks for any help!
2. Jan 2, 2009
### HallsofIvy
You can certainly find out the average force on the egg (finding the force at each instant would be far more difficult). I would suggest using "conservation of energy". If the egg has mass m and initial speed v, its kinetic energy is (1/2)mv<sup>2</sup>. After it has stopped its kinetic energy is, of course, 0 so the change in kinetic energy is (1/2)mv<sup>2</sup> and that must be equal to the work done on the egg: force times distance. If F is the (average) force with which the egg hits the wall and x is "the distance the egg travels while being absorbed into the sponginess" then Fx= (1/2)mv<sup>2</sup> so F= (1/2)mv<sup>2</sup>/x.
3. Jan 2, 2009
### fumalicious
Excellent! Thank you! It was that x = distance factor I was messing up in my head.. I was thinking I needed to input the difference in time rather then distance... man I miss doing this stuff. Thanks again!
Similar Discussions: Impulse how to figure out? | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8654777407646179, "perplexity": 848.7361311478152}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084890823.81/warc/CC-MAIN-20180121175418-20180121195418-00141.warc.gz"} |
https://stkwans.blogspot.com/2012/05/ | ## Saturday, May 19, 2012
### SDHC USB Bootloader and Logging Firmware work!
I have the old Logomatic 2.3 working with the new SDHC USB bootloader. At first, FAT32 was not enabled. because the mass storage part doesn't even need a filesystem driver, the host takes care of it. However, In order to find and install FW.SFE, the bootloader needs FAT32 however, so this version has it.
Also, the old Logomatic firmware has been updated the minimum amount to use SDHC and FAT32.
All of this works for me, and generates log files, but it sometimes takes a LONG time to mount over USB (sometimes a minute or more).
So now I have put my code where my mouth is.
Logomatic_SDHC_FAT32.zip
## Friday, May 18, 2012
### More on SDHC
So here's the problem. There are in fact two SD card drivers in the Logomatic firmware. Hey, by the engineering method, anything that works is good, and the Logomatic code works, but it's not great code. There are entire sections that are included but not used, like the USB driver in the main logging firmware. Now we have two pieces of code to do the same thing -- access the SD card. There is Roland Riegel's code used by rootdir.c and used by both the bootloader and main code to read and write the card, and there is the code used by the USB driver, which is entirely separate and entirely unready to do SDHC.
So, I am going to update the USB driver to use Roland's code. This just means mapping what the code is doing now to the various parts of sd_raw.c . Piece of cake, probably. We'll see.
Anyway, once this is done, I'll post a message about it on the Sparkfun forums, direct them here, and get literally some readers on this blog, rather than just myself like I get now.
No bragging until I can put my code where my mouth is.
By the way: I am doing all of this development on the Loginator 1.1, so the SD card slot and USB port work. Yay for me!
### The LPC1768
It's sooooo close to being awesome. Cortex M3 with all the improvements (don't be scared by the word Harvard, the program-visible memory map is flat) and full pin compatibility with the 2368.
Almost.
This part has no SD/MMC port. Still, with SPI and DMA, maybe we don't need SD/MMC. The part is otherwise pin-compatible with the 2368, so the 2368 breakout board should work with a 1768 also.
I am going to get a 2368 talking to an SD card and sensor before I try messing around with the 1768.
I have every confidence that the board is correct. I have tested that the known bugs in the old board have been eradicated. I have every confidence that the parts are properly placed and that all joints are good. I have tested the power supply, charge circuit, and lights.
So why am I not more confident in this board?
Is it live...
...or is it Memorex?
All of the switches and the battery terminal were partially melted/burned with hot air. The power switch is especially bad. Everything seems to work, though. It's just ugly. Next time, we bake the plastic parts. Maybe we bake everything. Maybe we salvage this board by lifting all the burned parts, replacing them, and baking it. Maybe we just don't make this board again. I would kinda like to get out of the 2148 business and into the 2368 business.
Update: The thing is alive, the Arduino terminal just doesn't know how to talk to it. I sent ? and saw 'Synchronized' on the logic analyzer (great device, I'll write a review some day). It just didn't show up in the serial terminal. This means that the controller is alive enough to communicate over serial, which means that the crystal and decoupling caps are on and the power is properly hooked up. The thing was running on battery when I tested this, so the whole battery part works too. Wow, I guess a lot is tested just with "Synchronized".
I wish these pictures showed the glorious royal purple and gold of the boards.
This is a NON-FLIGHT configuration. Not that the Loginator is ever intended to fly, anyway. This is just so that I can learn how to talk to the sensors and get the IMUinator working
## Wednesday, May 16, 2012
### 11DoF is working
I finally put together an 11DoF. All sensors are on board, but I decided to forgo the OR gates until I see that I need them. That means that both solder bridges on the back are closed, and the board is subject to Analog silliness if it decides to show its head.
Here we have the design...
And here is the physical implementation. Is reality ever as clean as design?
All of these sensors work, in that the I2C compass and baro/temp sensor actually work, and the SPI accel and gyro respond to SPI commands and return their proper chip IDs. I haven't tested full functionality on those guys yet.
So, do I start making and selling these things for $50 each? Or do I just release the design and say "have at it" yourself? If the latter, here are the files: 11DoF Schematic (Eagle 6.x) 11DoF Board Next version? There's always a next version. Both STMicro (makers of the L3G4200D) and Invensense (makers of the ITG3200 that I gave a glowing review to) have 6DoF sensors, and one of them even makes a 9DoF sensor with a magnetometer in the same chip as the accelerometer and gyro. The problem is that these parts are not yet available from Digikey, and therefore not really available at all. Also, the interfaces are ugly: Both parts have two SPI interfaces. The Invensense part has one for the gyro and one for the accelerometer, while the STMicro part has one for the gyro and one for the acc/compass. It is almost as if two devices are just crammed into the same case. I can cram together parts, in fact that's what the 11DoF board is. I want a 6/9DoF part to have a single SPI interface with a single chip select, and perhaps more importantly, I want the acc and gyro to sample at the same time and have one interrupt line. ## Wednesday, May 9, 2012 ### Designing a large charlieplex I saw a new cool way to design a charlieplex, one which is easy and obvious, even for an extremely large LED matrix. This was buried in a post below where I blather on about my own problems, so I broke it out into a post that Google is more likely to find. ## Monday, May 7, 2012 ### Details Matter... ...and they seem to cost about$50 each.
The boards for Precision 1.1 arrived on Saturday, part of an ocean of purple boards. I had previously ordered all the electronics for it, so I was all ready to assemble it, except...
1. In Eagle, I copied the crystal from some other source, and it was still labelled 12MHz like it was from some LPC2148 board. Before, I had manually ordered parts, but this time I used add-digikey.ulp, which dutifully noted that the part was 12MHz and the same case as the Logomatic crystals, so it ordered a 12MHz crystal and I missed it.
2. I had decided to use 91Ω resistors to try to solve the "extra lights" problem, but after having the clock set up, I decided that brightness was more important than extra lights, so I decided back to use 47Ω resistors like with Precision 1.0
This wasn't that much of a problem, as I had a complete but unusable board from a previous forgotten detail, so I could lift the 47Ω packs and 16MHz crystal from it, without ruining the working front board I already had. This avoids the "one brief shining moment" problem, when you have something that kinda works, but you want to improve it and destroy it in the process. I still have a working Precision 1.0 front board.
Now for today's $50 detail. The primary features of Precision 1.1 are the green wire fixes from last time and a port for the UP501 GPS unit in place of the EM406 port from 1.0. Well, I was planning on using the back board from Precision 1.0 as-is, since it already has$50 of blue and green lights on it. However, it has the old GPS port on it, with certain pins grounded and certain pins connected to VCC - the wrong pins, as it turns out. One of the new 3.3V pins matches one of the old VCC pins, so there is a direct 1.7V short, which I'm surprised didn't completely burn out the FT232. Maybe it did partially burn it out, but there is no way to check right now. The new PPS pin is grounded on the old board, in a flood of polygon that is impossible to isolate. Even though the back board has no electronics on it, it still interferes. This is the \$50 detail. Now I have to order a new set of lights. Or... I can lift the lights off of the old board, but that would create a brief shining moment problem. So, it will be new lights. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.24553067982196808, "perplexity": 1969.2645274313186}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-30/segments/1531676589618.52/warc/CC-MAIN-20180717070721-20180717090721-00557.warc.gz"} |
https://uwaterloo.ca/graduate-studies-postdoctoral-affairs/future-students/programs/german-ma-intercultural-german-studies-waterloo | # German - MA (Intercultural German Studies) at Waterloo
## At a glance:
### Research areas
• Applied Linguistics/Language Acquisition
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• Minimum average of 78% overall in final two years.
• Students whose native language is neither English nor German and who have not taken their first degree in a program taught in either language will have their language skills assessed by the admitting university.
• While every student will be registered at both the University of Waterloo and the Universität Mannheim during the two-year program, students should apply to the university that they will consider their home-university, via that university’s application system. This means that Canadian students should apply to the University of Waterloo while German students should apply to the Universität Mannheim.
• Proof of English language proficiency, if applicable. TOEFL 90 (writing 25, speaking 25), IELTS 7.0 (writing 6.5, speaking 6.5)
### Approximate tuition, fees, and living costs
• Canadian and permanent resident students, full-time: $2,254.00 tuition and$470.90 incidental fees per term (as of fall 2019)
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• Due to funding restrictions, the Faculty of Arts is currently limiting the number of international students we can admit. Please contact the department's Associate Chair, Graduate Studies prior to applying to discuss your interest in this program.
• Study and living costs | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.183553084731102, "perplexity": 9191.638477564939}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986666959.47/warc/CC-MAIN-20191016090425-20191016113925-00203.warc.gz"} |
http://physics.stackexchange.com/questions/35690/classical-dynamics-on-group-manifold-su2 | # classical dynamics on group manifold SU(2)
I am trying to understand how to formulate classical dynamics on group manifold SU(2). This will be an exercise for me to the more advanced subject of path integral on group manifold.
Does someone know of good (pedestrian) lecture notes on classical dynamics on SU(2)? For example, why the free particle Lagrangian look like that: $L=\frac{1}{2}tr\dot{U}\dot{U}^\dagger$? why the trace , whats the role of $U$?
-
Please see the following work, by George Chavchanidze, for a full solution of the classical and quantum dynamics of a particle moving freely on SU(2). The solution can be summarized as follows:
At the classical level, the group SU(2), equipped with the invariant metric is isometric to the round three sphere $S^3$. Thus the free particle trajectories (which are geodesics) are great circles on $S^3$.
More importantly, the Noether charges corresponding to the invariance of the dynamics under the action of $SU(2)$ are the angular momentum components. Which are conserved both classically and quantum mechanically.
At the quantum level all matrix element of a representation of SU(2) are solutions of the free Schrodinger equation on the group manifold, this is the Peter-Weyl theorem.
The reason that the Lagrangian takes the given form is because in the canonical coordinates $\{\phi_1, \phi_2, \phi_3 \}$, such that $U=e^{i\sigma_k \phi_k}$ (where $\sigma_k$ are the Pauli matrices), the Lagrangian takes the form
$L= \frac{1}{2} tr(\dot{U} \dot{U}) = \frac{1}{2} g_{ij}\dot{ \phi}_i\dot{ \phi}_j$
where $g_{ij}$ is the invariant metric on $SU(2)$ and the Euler-Lagrange equation corresponding to this metric is the geodesic equation.
Finally, a good review of the classical and quantum dynamics on an arbitrary compact group manifolds by: Marinov and Terentyev (In this review the quantum dynamics is treated by means of the path integral) is available in Prof. Marinov's memorial page.
Update related to the Hydrogen atom:
The dynamics of the electon in the hydrogen atom is not a free motion on a group manifold. However, Lie groups play a very important role in the hydrogen atom dynamics. Classical and quantum dynamics of the hydrogen atom can be constructed geometrically, on phase spaces which are coadjoint orbits (which are certain coset spaces) of the group $SO(3,2)$, please see for example the following work by: Bruno Cordani. (The people of geometric quantization often refer to the hydrogen atom problem by the name of Kepler problem for the obvious reason).
It is important to mention that here the coadjoint orbits constitute of the full phase space, and not of the configuration space, i.e., the directions along the "momenta" are also curved in contrast to the free motion where the momenta are "flat" (motion on a cotangent bundle). Dynamis of this form requires a different type of path integrals sometimes named by "Coherent state path integrals". The research on these subjects is still ongoing.
-
Thanks for the explanation. I will look at the two papers especially Marinov's one. Basically, does path integral on SU(2) is the way to calculate path integral for the hydrogen atom? – bill Sep 5 '12 at 14:33
I added an update answering the question about the hydrogen atom – David Bar Moshe Sep 5 '12 at 16:21
I will read more about it, toda – bill Sep 5 '12 at 16:41 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8636886477470398, "perplexity": 374.57223691433586}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246660628.16/warc/CC-MAIN-20150417045740-00205-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://physics.stackexchange.com/questions/176518/why-is-the-actual-gauge-group-of-the-standard-model-su3-times-su2-times?noredirect=1 | # Why is the “actual” gauge group of the standard model $SU(3) \times SU(2) \times U(1) /N$?
In this paper John Baez says the actual gauge group of the standard model is $SU(3) \times SU(2) \times U(1) /N$. Can someone explain the logic behind this line of thought?
• Firstly, does this group $N$ has some name?
• How can we see that $N$ acts "trivially on all the particles in the Standard Model" ?
• Does this factoring change anything or why isn't this "real" gauge group mentioned anywhere else?
• The logic behind this line of thought will, obviously, be contained in the paper. I think you should make your question (a lot) more specific: What exactly do you not understand? – Danu Apr 16 '15 at 18:26
• Now that I've taken a look at the paper, it is even more unclear to me what your issue is. The reasoning is simple, almost trivial. There is a "redundant subgroup", so we quotient it out. That's it. What's your issue? – Danu Apr 16 '15 at 18:32
• @Danu Could you elaborate why this is a "redundant subgroup"? Why redundant? Subgroup of which group? I can't see why $N$ "acts trivially on all particles"... And lastly, why isn't this mentioned anywhere else if it is that obvious? – Tim Apr 16 '15 at 19:48
• Honestly, I don't really know why Baez starts by saying the things he does---I just think that the reasoning he presents is quite simple. Now that you've updated the question, I think it's much better and I have upvoted accordingly. – Danu Apr 16 '15 at 20:12
Baez actually has another paper (with Huerta) that goes into more detail about this. In particular, Sec. 3.1 is where it's explained, along with some nice examples. The upshot is that the hypercharges of known particles work out just right so that the action of that generator is trivial. Specifically, we have
Left-handed quark Y = even integer + 1/3
Left-handed lepton Y = odd integer
Right-handed quark Y = odd integer + 1/3
Right-handed lepton Y = even integer
Because these are the only values for known fermions in the Standard Model, that generator does nothing. So basically, you can just take the full group modulo the subgroup generated by $(\alpha, \alpha^{-3}, \alpha^2)$ -- where $\alpha$ is a sixth root of unity.
There's also this paper by Saller, which goes into greater detail about the "central correlations" of the Standard Model's gauge group, but in a more technical presentation. Saller also goes into some detail in chapter 6.5.3 of his book.
• Thanks for the great reading recommendation. I found the explanation in books.google.de/… very illuminating, too – Tim Apr 17 '15 at 8:41
How can we see that the group $N$ generated by $$g = (e^{2\pi i/3} I, -I, e^{i\pi /3}) \in SU(3)\times SU(2)\times U(1)$$ acts trivially on all fields in the Standard Model?
First of all, note that $g$ is in the center of $SU(3)\times SU(2)\times U(1)$. Therefore its representative in the adjoint representation is the identity. Since gauge bosons transform in the adjoint representation, $N$ acts trivially on them.
The left-handed lepton fields are in the trivial representation of $SU(3)$ and are an $SU(2)\times U(1)$ doublet, $$\Psi = \begin{pmatrix} \nu_L \\ \psi_L \end{pmatrix}.$$ Baez is using a normalization of charge such that these fields have $U(1)$ charge $-3$., so they also transform trivially under $N$. The right-handed lepton $\psi_R$ has $U(1)$ charge $-6$ in this system, so it too is trivial.
The left (right) handed quarks have $U(1)$ charge $1$ ($4$ or $-2$) in this system and transform under $SU(3)$. It is simple to see that they also transform trivially under $N$.
(Note that various sources put the $1/3$ ratio between quark and lepton charges in various places, so be careful comparing.)
The main point is that if one has a consistent gauge theory containing matter with gauge group $$G:=SU(3)\times SU(2)\times U(1),$$ and if one divides $G$ with a normal subgroup $N$, then the matter representations of the matter fields could potentially become multi-valued. However, it is possible to choose $N=\mathbb{Z}_6$ in such a way that the standard model matter fields are invariant. And $N=\mathbb{Z}_6$ happens to be the maximal possible in this case.
See also this & this Phys.SE posts and links therein for a similar discussion for the electroweak sector. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9064241647720337, "perplexity": 274.8345419856266}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439735881.90/warc/CC-MAIN-20200804161521-20200804191521-00012.warc.gz"} |
http://zbmath.org/?q=an:0970.65086 | # zbMATH — the first resource for mathematics
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Asymptotic correction of Numerov’s eigenvalue estimates with natural boundary conditions. (English) Zbl 0970.65086
The method of asymptotic correction was first studied by this author to improve numerical approximations to eigenvalues of regular Sturm-Liouville problems
$-{y}^{\text{'}\text{'}}+qy=\lambda y,\phantom{\rule{1.em}{0ex}}y\left(a\right)=y\right)\pi \right)=0·$
The key idea of this method is that, at least for sufficiently $q$ and for certain classes of finite difference and finite element schemes, the leading asymptotic term in the error is a computed eigenvalue is independent of $a$. Asymptotic correction, at negligible extra cost, can greatly improve the accuracy of approximations to higher eigenvalues. Here, the method is extended to problems with natural boundary conditions to improve approximations obtained by Numerov’s finite difference scheme.
##### MSC:
65L15 Eigenvalue problems for ODE (numerical methods) 65L12 Finite difference methods for ODE (numerical methods) 34L16 Numerical approximation of eigenvalues and of other parts of the spectrum 34B24 Sturm-Liouville theory | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 3, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7978082895278931, "perplexity": 6811.505649521837}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-48/segments/1386164921422/warc/CC-MAIN-20131204134841-00085-ip-10-33-133-15.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/need-help-inverse-of-an-operator.7777/ | # Need help! Inverse of an operator
1. Oct 26, 2003
### einai
Another quantum question.....I feel dumb .
A Hermitian operator A has the spectral decomposition
A = Σ an|n><n| (summation in n)
where A|n> = an|n> (the an's are eigenvalues of A, and |n>'s the eigenstates).
So, how can I find the spectral decomposition of the inverse of A so that
AA-1 = A-1A = 1?
My intuition would be A = Σ (1/an)|n><n| (summation in n), since 1 = Σ |k><k| (summation in k), but I don't think it's that easy.
2. Oct 26, 2003
### Hurkyl
Staff Emeritus
Try multiplying the given sum for A and your sum for A-1 and see if you get 1 as the answer.
3. Oct 26, 2003
### einai
Thanks. I have a question about multiplying the 2 sums though. Should I make n --> n' for one of them, then sum over n and n'? Like this:
A = Σ an|n><n| (summation in n)
A-1 = Σ (1/an')|n'><n'| (summation in n')
then AA-1 = ΣΣ an(1/an') |n><n|n'><n'| (summation in n and n') ?
And what is the condition imposed on A so that the inverse exists? I have no idea...
Last edited: Oct 26, 2003
4. Oct 26, 2003
### Hurkyl
Staff Emeritus
Right, that's how you do the summation. (it will simplify to 1)
As for the condition imposed on A, your formula for A-1 contains a strong hint as to what that condition might me...
5. Oct 26, 2003
### einai
Thank you!
Hmm......is it that A and A-1 must have the same eigenstates, so that <n|n'> gives a delta function? And eigenvalues of A must be none zero otherwise the term in the inverse diverges?
6. Oct 26, 2003
### Hurkyl
Staff Emeritus
It is true that A and A-1 have the same eigenstates. For example, if |1> is an eigenstate of A with nonzero eigenvalue λ, then:
|1> = A-1A|1> = A-1λ|1>
and thus A-1|1> = λ-1|1>
So any eigenstate of A is an eigenstate of A-1 (and vice-versa, by symmetry).
More importantly, we can always choose an orthonormal eigenbasis, in which <n|n'> would indeed be a delta function. (I would presume the basis used by spectral decomposition would be orthonormal, but don't quote me on that!)
And yes, the right condition here is that all of the eigenvalues of A be nonzero. However, there is still work to do! At the moment, your formula only proves that if all of the eigenvalues of A are nonzero then there exists an inverse! You still need to prove that if A has a zero eigenvalue then it cannot have an inverse.
7. Oct 26, 2003
### einai
That's a very good explanation, thank you.
Yes, they're orthonormal basis since it's the summation over the eigenstates.
Yikes, I'm not too sure if I understand this part... I mean, if A has a zero eigenvalue, then its inverse would have an eigenstate with eigenvalue 1/0 which diverges....couldn't that prove A cannot have an inverse?
8. Oct 26, 2003
### Hurkyl
Staff Emeritus
I'm not sure if you're off the right track, or if you're on the right track but are missing a detail or two... so I'll give an example of a wrong proof and a right proof.
Wrong proof:
A-1 is given by that formula, and if we plug in a zero for one of the eigenvalues, the sum diverges, so A-1 doesn't exist.
This is wrong because you haven't proved that A-1 must have the form given by your formula; you can only prove that the formula works when the eigenvalues are nonzero.
It might be the case that there's another formula that will give you the inverse when one of the eigenvalues is zero. (It turns out that this is not the case, but from just the information I mentioned above, we can't determine this fact!)
Right proof:
Suppose |1> is an eigenstate of A with eigenvalue 0. Then:
|1> = A-1A|1> = A-10|1> = A-1 0 = 0
But since |1> is not the zero vector, we have a contradiction in assuming A-1 exists.
This is kinda like what you were saying, because we have:
|1> = 0 A-1 |1>
Implying A-1 has an "infinite" eigenvalue which is impossible... I just wasn't sure if you were aiming at this ponit or not.
9. Oct 26, 2003
### einai
Oh, I see! Now I understand... I've always been bad at proving things . Thank you again for your help!
Similar Discussions: Need help! Inverse of an operator | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9657920598983765, "perplexity": 1081.5935250522177}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-17/segments/1492917118477.15/warc/CC-MAIN-20170423031158-00610-ip-10-145-167-34.ec2.internal.warc.gz"} |
http://mathoverflow.net/questions/111637/intersection-of-vector-spaces?sort=votes | # Intersection of vector spaces
Let $\{v_{1,j},\ldots, v_{n,j}\}$ be a basis of the $n$-dimensional vector space $V$ for $j=1\ldots k$ (and assume $2k\leq n$). Let $V_i$ be the subspace spanned by $v_{i,1},\ldots, v_{i,k}$ for $i=1\ldots n$. (So the dimension of each $V_i$ can be anything between $1$ and $k$.) Is it true that $V_1\cap V_2\cap \ldots \cap V_{2k}=0$ (or likewise any intersection of $2k$ of the $V_i$ is trivial)?
(The answer to the question is needed to proof a quite technical lemma, the details of which I prefer not to spread in full length. In any case I want to do something like span "as much of $V$ as possible, using as few $V_i$ as possible".)
I seem not be able to construct a counterexample, neither to do a proof by induction, though I suspect the latter should be possible. Any pointer to a reference or hint to a simple argument is appreciated!
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I believe the answer is no if $n\ge4$. Here is a counterexample for $n=4$, $k=2$: Let $v$ be the sum $v_{1,1}+v_{2,1}+v_{3,1}+v_{4,1}$ of the vectors of the first basis. Define the second basis by $v_{i,2}=v-v_{i,1}$. Then $v\in V_i$ for $i=1,2,3,4$, a contradiction as $v\ne 0$. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9744486808776855, "perplexity": 91.91050589760351}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-35/segments/1440645298065.68/warc/CC-MAIN-20150827031458-00041-ip-10-171-96-226.ec2.internal.warc.gz"} |
http://math.stackexchange.com/questions/275874/a-system-of-equations-of-vietnamese-mathematical-olympiad-2013?answertab=oldest | # A system of equations of Vietnamese Mathematical Olympiad 2013
This is a system of equation of Vietnamese Mathematical Olympiad 2013, the first day. Solve the system of equations $$\begin{cases} \sqrt{\sin^2 x + \dfrac{1}{\sin^2 x}} + \sqrt{\cos^2 y + \dfrac{1}{\cos^2 y}} = \sqrt{\dfrac{20y}{x+y}},\\ \sqrt{\sin^2 y + \dfrac{1}{\sin^2 y}} + \sqrt{\cos^2 x + \dfrac{1}{\cos^2 x}} = \sqrt{\dfrac{20x}{x+y}}. \end{cases}$$
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Hint: add the equations and show that $\sqrt{\sin^2 x + \dfrac{1}{\sin^2 x}} + \sqrt{\cos^2 x + \dfrac{1}{\cos^2 x}}$ is minimized when $\sin^2 x = \cos^2 x = 1/2$. The rest is easy. – whuber Jan 11 '13 at 18:04
Cross-posted at mathematica.stackexchange.com/questions/17621/…. – whuber Jan 13 '13 at 0:19 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9477044343948364, "perplexity": 944.4191722478735}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-35/segments/1440645265792.74/warc/CC-MAIN-20150827031425-00288-ip-10-171-96-226.ec2.internal.warc.gz"} |
https://icml.cc/Conferences/2021/ScheduleMultitrack?event=8761 | Timezone: »
Poster
Single Pass Entrywise-Transformed Low Rank Approximation
Yifei Jiang · Yi Li · Yiming Sun · Jiaxin Wang · David Woodruff
Thu Jul 22 09:00 PM -- 11:00 PM (PDT) @ None #None
In applications such as natural language processing or computer vision, one is given a large $n \times n$ matrix $A = (a_{i,j})$ and would like to compute a matrix decomposition, e.g., a low rank approximation, of a function $f(A) = (f(a_{i,j}))$ applied entrywise to $A$. A very important special case is the likelihood function $f\left( A \right ) = \log{\left( \left| a_{ij}\right| +1\right)}$. A natural way to do this would be to simply apply $f$ to each entry of $A$, and then compute the matrix decomposition, but this requires storing all of $A$ as well as multiple passes over its entries. Recent work of Liang et al. shows how to find a rank-$k$ factorization to $f(A)$ using only $n \cdot \poly(\eps^{-1}k\log n)$ words of memory, with overall error $10\|f(A)-[f(A)]_k\|_F^2 + \poly(\epsilon/k) \|f(A)\|_{1,2}^2$, where $[f(A)]_k$ is the best rank-$k$ approximation to $f(A)$ and $\|f(A)\|_{1,2}^2$ is the square of the sum of Euclidean lengths of rows of $f(A)$. Their algorithm uses $3$ passes over the entries of $A$. The authors pose the open question of obtaining an algorithm with $n \cdot \poly(\eps^{-1}k\log n)$ words of memory using only a single pass over the entries of $A$. In this paper we resolve this open question, obtaining the first single-pass algorithm for this problem and for the same class of functions $f$ studied by Liang et al. Moreover, our error is $\|f(A)-[f(A)]_k\|_F^2 + \poly(\epsilon/k) \|f(A)\|_F^2$, where $\|f(A)\|_F^2$ is the sum of squares of Euclidean lengths of rows of $f(A)$. Thus our error is significantly smaller, as it removes the factor of $10$ and also $\|f(A)\|_F^2 \leq \|f(A)\|_{1,2}^2$. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8911569714546204, "perplexity": 187.9786066114475}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585203.61/warc/CC-MAIN-20211018124412-20211018154412-00595.warc.gz"} |
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# One pump drains one-half of a pond in 3 hours, and then a second pump
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One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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Updated on: 27 Jan 2016, 10:22
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One pump drains one-half of a pond in 3 hours, and then a second pump starts draining the pond. The two pumps working together finish emptying the pond in one-half hour. How long would it take the second pump to drain the pond if it had to do the job alone?
A. 1 hour
B. 1.2 hour
C. 3 hours
D. 5 hours
E. 6 hours
Originally posted by saumzi on 16 Oct 2011, 09:55.
Last edited by Bunuel on 27 Jan 2016, 10:22, edited 1 time in total.
Renamed the topic and edited the question.
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Re: One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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27 Jan 2016, 10:17
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saumzi wrote:
i know its terribly easy but still i m stuck somewhere...
One pump drains one-half of a pond in 3 hours, and then a second pump starts draining the pond.The two pumps working together finish emptying the pond in one-half hour.How long would it take the second pump to drain the pond if it had to do the job alone???
A.1 hour
B.1.2 hour
C.3 hours
D.5 hours
E.6 hours
The tricky part here, I believed is one half hour = 1/2. Then everything would be easy.
We have the 1st pump working rate/hour = 1/2 : 3 = 1/6
Working rate of 2 pumps: 1/2 : 1/2 = 1.
Working rate of 2nd pump: 1 -1/6 = 5/6 --> Time taken for the 2nd pump to finish: 1 : 5/6 = 6/5 = 1.2 hours.
Hope it help
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Re: One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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16 Oct 2011, 10:56
saumzi wrote:
i know its terribly easy but still i m stuck somewhere...
One pump drains one-half of a pond in 3 hours, and then a second pump starts draining the pond.The two pumps working together finish emptying the pond in one-half hour.How long would it take the second pump to drain the pond if it had to do the job alone???
A.1 hour
B.1.2 hour
C.3 hours
D.5 hours
E.6 hours
Can you please check the question? I am getting the answer which is not in option.
Pump 1 drains half of the pond in 3 hrs ==>it will take 6hrs for Pump 1 to drain the entire pond.
Number of hrs taken by pump 2 = Y
If both pumps working together will empty the pond in 1.5hrs==>3/2
==>1/6 + 1/Y = 2/3
==>1/Y = 2/3-1/6 ==>(4-1)/6 =1/2
Y =2
Number of hrs taken by Pump 2 to drain the entire pond = 2hrs
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Re: One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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16 Oct 2011, 12:26
1/6 + 1/Tb = 1/1.5
1/6 + 1/Tb= 2/3
solving for Tb= 2 hrs
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Re: One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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27 Jan 2016, 20:04
First pump drains 1/2 of the tank in 3 hours
so 6 hours it will take to drain the full tank.
Let, 2nd pump drains the full tank in a hours
so both together can drain (1/6+1/a) part in 1 hour
son in 1/2 hour they drain 1/2*(1/6+1/a) part of the tank
given that in 1/2 hour they drain 1/2 of the tank
hence we can say
1/2*(1/6+1/a) = 1/2
solving u get a = 6/5=1.2
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One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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17 Feb 2016, 15:48
if pump 1 drains 1/12 of pond in 1/2 hour,
then pump 2 must drain 1/2-1/12=5/12 of pond in 1/2 hour
let t=pump 2's time to drain entire pond alone
(5/12)/(1/2))=1/t
t=1.2 hours
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One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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04 Mar 2016, 20:58
rate of pump 1=1/6
rate of pump 1+pump 2=1
rate of pump 2=1-(1/6)=5/6
inverting, 6/5=1.2 hours for pump 2 to drain pond alone
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Re: One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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13 Aug 2017, 19:48
Let the total capacity of pond be 6.
Pump 1 drains 3 in 3 hrs, i.e. 1 per hour
both pumps finishes draining remaining 3 in 0.5 hour, i.e 6 per hour
Thus rate of pump 2 has to be (total rate - rate of pump 1) = (6-1) = 5 per hour
Pump 2 needs to drain complete 6 @ 5 per hour so time taken is $$\frac{6}{5}$$ = 1.2 hrs
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Re: One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink]
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13 Aug 2017, 19:55
performance of the first pomp 1/6
then 1/6*1/2+x*1/2=1/2 (half of the pound)
1/12 +x/2 = 1/2
x/2=5/12
12x= 10
x =10/12
so the performance of the second pomp is 5/6
then if the first one has performance of 1/6 and drains the pound in 6 hours, then the second will do that in 6/5 = 1.2h
Re: One pump drains one-half of a pond in 3 hours, and then a second pump [#permalink] 13 Aug 2017, 19:55
Display posts from previous: Sort by | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6145561337471008, "perplexity": 9776.150432491448}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-22/segments/1558232257624.9/warc/CC-MAIN-20190524124534-20190524150534-00209.warc.gz"} |
https://www.jse.ac.cn/EN/Y2017/V55/I3/200 | J Syst Evol ›› 2017, Vol. 55 ›› Issue (3): 200-207.
• Research Articles •
### Identification and characterization of Rubisco activase genes in Oryza punctata
Si Xu1†, Zong-Yan Qin1, Pi-Chang Gong2, Qian-Li Dong3, and Ying Bao1†*
1. 1School of Life Sciences, Qufu Normal University, Qufu 273165, Shandong, China
2State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
3Key Laboratory of Molecular Epigenetics of the Ministry of Education, Northeast Normal University, Changchun 130024, China These authors contributed equally to this work.
• Received:2016-09-27 Published:2017-05-12
Abstract: Rubisco activase (Rca), a specific chaperone, catalyzes the in vivo activation of Rubisco, and thus plays a major role in plant photosynthesis. Although the genes encoding Rubisco activase have been studied in many model or economic plants, few studies have analyzed their homologs in plants of closely related crop species. In this study, an Rca gene was identified and characterized in a wild relative of rice, Oryza punctata Kotschy ex Steud. The gene was 2747 bp long and possessed six exons and five introns with 47% GC content. Furthermore, cDNA sequencing produced two transcripts, RcaL and RcaS, that differed in the sequence by an inclusion of 99 bp at the carboxy terminus of RcaL. Sequence comparison between the two transcripts and the genomic DNA showed that there was a 20-bp alternative splicing event that occurred at the fifth intron of the gene leading to the synthesis of a short polypeptide. The leaf transcriptome analysis showed that RcaS had a higher expression level than that of RcaL in a normal growth environment. In addition, the yeast two-hybrid assays showed the small isoform of Rubisco activase in close contact with the large subunit of the Rubisco in this species, supporting the side-on binding model of interaction between two proteins. This study broadens our understanding of the molecular characteristics of some essential genes in photosynthesis. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.17551305890083313, "perplexity": 9492.420370408168}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323584913.24/warc/CC-MAIN-20211016170013-20211016200013-00541.warc.gz"} |
http://oftankonyv.reak.bme.hu/tiki-index.php?page=T2+relaxation&structure=Tank%C3%B6nyv+Fizikusoknak | # T2 relaxation
The other relaxation process called transverse or relaxation will be presented here intuitively in a classical model. Assume we have a bunch of magnetic moments originally point to the direction of the external field, then we rotate them to the transverse plane with an RF pulse. The local magnetic field a specific spin experiences is the sum of the external field and the small fields of the neighbouring spins. The latter small fields vary in space that leads to different local precession frequencies. Therefore the spins tend to fan out in time as shown in Figure 1, this is usually called dephasing. Since the measureable magnetization is the vector (or complex) sum of the individual magnetic moments, the net magnetization decreases over time. This reduction brings forth another exponential decay with characteristic time that adds to the time derivative of the transverse component of the magnetization. We can express it by adding an exponential term to the transverse component of the magnetization. In the laboraroty frame:
(1)
And in the rotating system:
(2)
If the frequency of the rotating frame equals to the Larmor frequency and there are no other magnetic fields like RF excitation then the effective field becomes zero and the solution of (2) become a simple exponential decay:
(3)
Figure 1. Dephasing of the individual moments in the rotating frame and the decreasing net magnetization as a result. | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9218876361846924, "perplexity": 338.7774433834376}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030334620.49/warc/CC-MAIN-20220925225000-20220926015000-00671.warc.gz"} |