url stringlengths 14 1.76k | text stringlengths 100 1.02M | metadata stringlengths 1.06k 1.1k |
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https://people.maths.bris.ac.uk/~matyd/GroupNames/288/C3xD6.C8.html | Copied to
clipboard
## G = C3×D6.C8order 288 = 25·32
### Direct product of C3 and D6.C8
Series: Derived Chief Lower central Upper central
Derived series C1 — C6 — C3×D6.C8
Chief series C1 — C3 — C6 — C12 — C24 — C3×C24 — S3×C24 — C3×D6.C8
Lower central C3 — C6 — C3×D6.C8
Upper central C1 — C24 — C48
Generators and relations for C3×D6.C8
G = < a,b,c,d | a3=b6=c2=1, d8=b3, ab=ba, ac=ca, ad=da, cbc=b-1, bd=db, dcd-1=b3c >
Subgroups: 102 in 57 conjugacy classes, 34 normal (all characteristic)
C1, C2, C2, C3 [×2], C3, C4, C4, C22, S3, C6 [×2], C6 [×2], C8, C8, C2×C4, C32, Dic3, C12 [×2], C12 [×2], D6, C2×C6, C16, C16, C2×C8, C3×S3, C3×C6, C3⋊C8, C24 [×2], C24 [×2], C4×S3, C2×C12, M5(2), C3×Dic3, C3×C12, S3×C6, C3⋊C16, C48 [×2], C48 [×2], S3×C8, C2×C24, C3×C3⋊C8, C3×C24, S3×C12, D6.C8, C3×M5(2), C3×C3⋊C16, C3×C48, S3×C24, C3×D6.C8
Quotients: C1, C2 [×3], C3, C4 [×2], C22, S3, C6 [×3], C8 [×2], C2×C4, C12 [×2], D6, C2×C6, C2×C8, C3×S3, C24 [×2], C4×S3, C2×C12, M5(2), S3×C6, S3×C8, C2×C24, S3×C12, D6.C8, C3×M5(2), S3×C24, C3×D6.C8
Smallest permutation representation of C3×D6.C8
On 96 points
Generators in S96
(1 61 39)(2 62 40)(3 63 41)(4 64 42)(5 49 43)(6 50 44)(7 51 45)(8 52 46)(9 53 47)(10 54 48)(11 55 33)(12 56 34)(13 57 35)(14 58 36)(15 59 37)(16 60 38)(17 83 78)(18 84 79)(19 85 80)(20 86 65)(21 87 66)(22 88 67)(23 89 68)(24 90 69)(25 91 70)(26 92 71)(27 93 72)(28 94 73)(29 95 74)(30 96 75)(31 81 76)(32 82 77)
(1 47 61 9 39 53)(2 48 62 10 40 54)(3 33 63 11 41 55)(4 34 64 12 42 56)(5 35 49 13 43 57)(6 36 50 14 44 58)(7 37 51 15 45 59)(8 38 52 16 46 60)(17 91 78 25 83 70)(18 92 79 26 84 71)(19 93 80 27 85 72)(20 94 65 28 86 73)(21 95 66 29 87 74)(22 96 67 30 88 75)(23 81 68 31 89 76)(24 82 69 32 90 77)
(1 76)(2 69)(3 78)(4 71)(5 80)(6 73)(7 66)(8 75)(9 68)(10 77)(11 70)(12 79)(13 72)(14 65)(15 74)(16 67)(17 63)(18 56)(19 49)(20 58)(21 51)(22 60)(23 53)(24 62)(25 55)(26 64)(27 57)(28 50)(29 59)(30 52)(31 61)(32 54)(33 91)(34 84)(35 93)(36 86)(37 95)(38 88)(39 81)(40 90)(41 83)(42 92)(43 85)(44 94)(45 87)(46 96)(47 89)(48 82)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16)(17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32)(33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48)(49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64)(65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80)(81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96)
G:=sub<Sym(96)| (1,61,39)(2,62,40)(3,63,41)(4,64,42)(5,49,43)(6,50,44)(7,51,45)(8,52,46)(9,53,47)(10,54,48)(11,55,33)(12,56,34)(13,57,35)(14,58,36)(15,59,37)(16,60,38)(17,83,78)(18,84,79)(19,85,80)(20,86,65)(21,87,66)(22,88,67)(23,89,68)(24,90,69)(25,91,70)(26,92,71)(27,93,72)(28,94,73)(29,95,74)(30,96,75)(31,81,76)(32,82,77), (1,47,61,9,39,53)(2,48,62,10,40,54)(3,33,63,11,41,55)(4,34,64,12,42,56)(5,35,49,13,43,57)(6,36,50,14,44,58)(7,37,51,15,45,59)(8,38,52,16,46,60)(17,91,78,25,83,70)(18,92,79,26,84,71)(19,93,80,27,85,72)(20,94,65,28,86,73)(21,95,66,29,87,74)(22,96,67,30,88,75)(23,81,68,31,89,76)(24,82,69,32,90,77), (1,76)(2,69)(3,78)(4,71)(5,80)(6,73)(7,66)(8,75)(9,68)(10,77)(11,70)(12,79)(13,72)(14,65)(15,74)(16,67)(17,63)(18,56)(19,49)(20,58)(21,51)(22,60)(23,53)(24,62)(25,55)(26,64)(27,57)(28,50)(29,59)(30,52)(31,61)(32,54)(33,91)(34,84)(35,93)(36,86)(37,95)(38,88)(39,81)(40,90)(41,83)(42,92)(43,85)(44,94)(45,87)(46,96)(47,89)(48,82), (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16)(17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32)(33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48)(49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64)(65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80)(81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96)>;
G:=Group( (1,61,39)(2,62,40)(3,63,41)(4,64,42)(5,49,43)(6,50,44)(7,51,45)(8,52,46)(9,53,47)(10,54,48)(11,55,33)(12,56,34)(13,57,35)(14,58,36)(15,59,37)(16,60,38)(17,83,78)(18,84,79)(19,85,80)(20,86,65)(21,87,66)(22,88,67)(23,89,68)(24,90,69)(25,91,70)(26,92,71)(27,93,72)(28,94,73)(29,95,74)(30,96,75)(31,81,76)(32,82,77), (1,47,61,9,39,53)(2,48,62,10,40,54)(3,33,63,11,41,55)(4,34,64,12,42,56)(5,35,49,13,43,57)(6,36,50,14,44,58)(7,37,51,15,45,59)(8,38,52,16,46,60)(17,91,78,25,83,70)(18,92,79,26,84,71)(19,93,80,27,85,72)(20,94,65,28,86,73)(21,95,66,29,87,74)(22,96,67,30,88,75)(23,81,68,31,89,76)(24,82,69,32,90,77), (1,76)(2,69)(3,78)(4,71)(5,80)(6,73)(7,66)(8,75)(9,68)(10,77)(11,70)(12,79)(13,72)(14,65)(15,74)(16,67)(17,63)(18,56)(19,49)(20,58)(21,51)(22,60)(23,53)(24,62)(25,55)(26,64)(27,57)(28,50)(29,59)(30,52)(31,61)(32,54)(33,91)(34,84)(35,93)(36,86)(37,95)(38,88)(39,81)(40,90)(41,83)(42,92)(43,85)(44,94)(45,87)(46,96)(47,89)(48,82), (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16)(17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32)(33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48)(49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64)(65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80)(81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96) );
G=PermutationGroup([(1,61,39),(2,62,40),(3,63,41),(4,64,42),(5,49,43),(6,50,44),(7,51,45),(8,52,46),(9,53,47),(10,54,48),(11,55,33),(12,56,34),(13,57,35),(14,58,36),(15,59,37),(16,60,38),(17,83,78),(18,84,79),(19,85,80),(20,86,65),(21,87,66),(22,88,67),(23,89,68),(24,90,69),(25,91,70),(26,92,71),(27,93,72),(28,94,73),(29,95,74),(30,96,75),(31,81,76),(32,82,77)], [(1,47,61,9,39,53),(2,48,62,10,40,54),(3,33,63,11,41,55),(4,34,64,12,42,56),(5,35,49,13,43,57),(6,36,50,14,44,58),(7,37,51,15,45,59),(8,38,52,16,46,60),(17,91,78,25,83,70),(18,92,79,26,84,71),(19,93,80,27,85,72),(20,94,65,28,86,73),(21,95,66,29,87,74),(22,96,67,30,88,75),(23,81,68,31,89,76),(24,82,69,32,90,77)], [(1,76),(2,69),(3,78),(4,71),(5,80),(6,73),(7,66),(8,75),(9,68),(10,77),(11,70),(12,79),(13,72),(14,65),(15,74),(16,67),(17,63),(18,56),(19,49),(20,58),(21,51),(22,60),(23,53),(24,62),(25,55),(26,64),(27,57),(28,50),(29,59),(30,52),(31,61),(32,54),(33,91),(34,84),(35,93),(36,86),(37,95),(38,88),(39,81),(40,90),(41,83),(42,92),(43,85),(44,94),(45,87),(46,96),(47,89),(48,82)], [(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16),(17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32),(33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48),(49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64),(65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80),(81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96)])
108 conjugacy classes
class 1 2A 2B 3A 3B 3C 3D 3E 4A 4B 4C 6A 6B 6C 6D 6E 6F 6G 8A 8B 8C 8D 8E 8F 12A 12B 12C 12D 12E ··· 12J 12K 12L 16A 16B 16C 16D 16E 16F 16G 16H 24A ··· 24H 24I ··· 24T 24U 24V 24W 24X 48A ··· 48AF 48AG ··· 48AN order 1 2 2 3 3 3 3 3 4 4 4 6 6 6 6 6 6 6 8 8 8 8 8 8 12 12 12 12 12 ··· 12 12 12 16 16 16 16 16 16 16 16 24 ··· 24 24 ··· 24 24 24 24 24 48 ··· 48 48 ··· 48 size 1 1 6 1 1 2 2 2 1 1 6 1 1 2 2 2 6 6 1 1 1 1 6 6 1 1 1 1 2 ··· 2 6 6 2 2 2 2 6 6 6 6 1 ··· 1 2 ··· 2 6 6 6 6 2 ··· 2 6 ··· 6
108 irreducible representations
dim 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 type + + + + + + image C1 C2 C2 C2 C3 C4 C4 C6 C6 C6 C8 C8 C12 C12 C24 C24 S3 D6 C3×S3 C4×S3 M5(2) S3×C6 S3×C8 S3×C12 D6.C8 C3×M5(2) S3×C24 C3×D6.C8 kernel C3×D6.C8 C3×C3⋊C16 C3×C48 S3×C24 D6.C8 C3×C3⋊C8 S3×C12 C3⋊C16 C48 S3×C8 C3×Dic3 S3×C6 C3⋊C8 C4×S3 Dic3 D6 C48 C24 C16 C12 C32 C8 C6 C4 C3 C3 C2 C1 # reps 1 1 1 1 2 2 2 2 2 2 4 4 4 4 8 8 1 1 2 2 4 2 4 4 8 8 8 16
Matrix representation of C3×D6.C8 in GL2(𝔽97) generated by
61 0 0 61
,
62 0 0 36
,
0 36 62 0
,
12 0 0 85
G:=sub<GL(2,GF(97))| [61,0,0,61],[62,0,0,36],[0,62,36,0],[12,0,0,85] >;
C3×D6.C8 in GAP, Magma, Sage, TeX
C_3\times D_6.C_8
% in TeX
G:=Group("C3xD6.C8");
// GroupNames label
G:=SmallGroup(288,232);
// by ID
G=gap.SmallGroup(288,232);
# by ID
G:=PCGroup([7,-2,-2,-3,-2,-2,-2,-3,701,92,80,102,9414]);
// Polycyclic
G:=Group<a,b,c,d|a^3=b^6=c^2=1,d^8=b^3,a*b=b*a,a*c=c*a,a*d=d*a,c*b*c=b^-1,b*d=d*b,d*c*d^-1=b^3*c>;
// generators/relations
×
𝔽 | {"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": 0.9936057925224304, "perplexity": 3121.404857183477}, "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-2020-05/segments/1579250593937.27/warc/CC-MAIN-20200118193018-20200118221018-00288.warc.gz"} |
https://latex-programming.fandom.com/wiki/Tabular_(LaTeX_environment) | The tabular environment can be used to insert tables in text mode.
## Syntax
Columns are separated by &, and each row ends with a double backslash \\:
\begin{tabular}[position]{column definition}
Lorum & ipsum & dolor \\
sit & amet & consectetur \\
\end{tabular}
### Column definition
A tabular environment takes one required parameter, the column definition. A column definition of lcr would left-align the first column, center the second column, and right-align the third column.
The column definition can include vertical bars, e.g. l|c|r, to draw vertical borders.
### Position
As the tabular environment is rendered inline as a single large character, the optional parameter position controls the position of the table relative to the baseline of the surrounding text:
b bottom c center (default) t top
## Floating tabular
To make the table float, simply include it in a table environment or a figure environment.
\usepackage{hyperref}
...
\begin{table}
\caption{Caption needs to be before the label.}
\centering
\begin{tabular}{lll}
...
\end{tabular}
\label{tbl:tablelabel}
\end{table}
See example at \autoref{tbl:tablelabel}.
The \centering command may be preferable to the center environment in a float, as the center environment will add a paragraph and create extra whitespace in the float.
A tabular environment may be nested within a minipage to allow side-by-side tables within a table or figure environment, or to place an image next to a table:
\begin{figure}
\begin{minipage}{2in}
... image ...
\end{minipage}
\begin{minipage}{2in}
\begin{tabular}{lll}
... table ...
\end{tabular}
\end{minipage}
\end{figure}
LaTeX doesn't require any packages to use tabular by itself, so tabular is ubiquitous. The limitations of tabular are that it doesn't add sufficient whitespace around cells.
The booktabs package has a few commands that vastly improve the quality of tabular's tables, and the documentation for booktabs has some advice on typesetting tables properly. | {"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": 0.9369433522224426, "perplexity": 4572.837817632279}, "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-2022-27/segments/1656103983398.56/warc/CC-MAIN-20220702010252-20220702040252-00663.warc.gz"} |
https://pcbmode.readthedocs.io/en/latest/text.html | # Text¶
One of the unique features of PCBmodE is that any font – as long as it is in SVG form – can be used for any text on the board.
## Fonts¶
SVG fonts have an SVG path for every glyph, and other useful information about how to place the font so the glyphs align. PCBmodE uses that information to place text on the board’s layers.
The folder in which PCBmodE looks for a font is defined in the the configuration file `pcbmode_config.json`.
```{
"locations":
{
"boards": "boards/",
"components": "components/",
"fonts": "fonts/",
"build": "build/",
"styles": "styles/"
}
}
```
When looking for a font file, PCBmodE will first look at the local project folder and then where `pcbmode.py` is.
Tip
When you find a font that you’d like to use, search for an SVG version of it. Many fonts at http://www.fontsquirrel.com have an SVG version for download.
## Defining text¶
A text definition looks like the following
```{
"type": "text",
"layers": ["bottom"],
"font-family": "Overlock-Regular-OTF-webfont",
"font-size": "1.5mm",
"letter-spacing": "0mm",
"line-height": "1.5mm",
"location": [
-32.39372,
-33.739699
],
"rotate": 0,
"style": "fill",
}
```
type
`text`: place a text element
layers (optional; default `["top"]`)
list: layers to place the shape on (even if placing on a single layer, the definition needs to be in a form of a list)
font-family
text: The name of the font file, without the `.svg`
font-size
float: font size in mm (the `mm` must be present)
value
text: the text to display; use `\n` for newline
letter-spacing (optional; default `0mm`)
float: positive/negative value increases/decreases the spacing. `0mm` maintains the natural spacing defined by the font
line-height (optional; defaults to `font-size`)
float: the distance between lines; a negative value is allowed
location (optional; default `[0, 0]`)
list: `x` and `y` to place the center of the text object
rotate (optional; default `0`)
float: rotation, clock-wise degrees
style (optional; default depends on sheet)
`stroke` or `fill`: style of the shape
stroke-width (optional; default depends on sheet; ignored unless `style` is `stroke`)
float: stroke width | {"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": 0.9477545022964478, "perplexity": 5278.902717174566}, "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-2021-21/segments/1620243988725.79/warc/CC-MAIN-20210506023918-20210506053918-00229.warc.gz"} |
http://mathhelpforum.com/differential-equations/124439-having-trouble-ode-step.html | # Math Help - Having Trouble With ODE Step
1. ## Having Trouble With ODE Step
Hey. Looking through my notes here and I'm having trouble with a jump they've made.
$
e^X+(Ye^X-X)\frac{dX}{dY}=0
$
This can be written as:
$
\frac{dY}{dX}+Y=Xe^{-X}
$
I've been sitting trying to see how the top line can be written as the bottom line but I seem to be stumped.
Any help would be greatly appreciated .
2. $e^{x}+(ye^{x}-x)\frac{dy}{dx}=0$
Mult by $\frac{dx}{dy}$ to get
$e^{x}\frac{dx}{dy}+(ye^{x}-x)=0$
Divide by $e^{x}$ to get
$\frac{dx}{dy}+y-xe^{-x}=0$
3. Ahh, It's seems very simple now. Thanks man .
4. Originally Posted by Macca567
Hey. Looking through my notes here and I'm having trouble with a jump they've made.
$
e^X+(Ye^X-X)\frac{dX}{dY}=0
$
This can be written as:
$
\frac{dY}{dX}+Y=Xe^{-X}
$
I've been sitting trying to see how the top line can be written as the bottom line but I seem to be stumped.
Any help would be greatly appreciated .
It is easy
$e^x + \left(ye^x - x\right)\frac{dx}{dy} = 0$
$e^x\frac{dy}{dx} + e^xy = x$
$\left(e^xy\right)^{'} = x$
$e^xy = \frac{x^2}{2} + C$
$y = \left(\frac{x^2}{2} + C\right)e^{-x}$
5. Originally Posted by Ment
It is easy
$e^x + \left(ye^x - x\right)\frac{dx}{dy} = 0$
$e^x\frac{dy}{dx} + e^xy = x$
The question was how to get to this line! You can't say "It is easy" and them just write it down!
$\left(e^xy\right)^{'} = x$
$e^xy = \frac{x^2}{2} + C$
$y = \left(\frac{x^2}{2} + C\right)e^{-x}$ | {"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": 19, "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": 0.8808401823043823, "perplexity": 600.9957188132795}, "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-2015-14/segments/1427131304412.34/warc/CC-MAIN-20150323172144-00163-ip-10-168-14-71.ec2.internal.warc.gz"} |
https://tex.stackexchange.com/questions/378140/purely-vertical-and-lateral-wires-for-circuitikz | # Purely vertical and lateral wires for circuitikz
I am attempting to diagram a simple approach to an equality testing circuit for two four-bit inputs. Instead of the wires being at an oblique angle to connect the two points of gate inputs and outputs, can I force the lines to be purely vertical and lateral with right angles as necessary to connect the points. I need to do this while maintaining the ability to label the wires as shown. When I first made the diagram, the wires were as I had hoped with the '-|' argument or operator in place of 'to', but I could not find a way to get wires instantiated with that method to accept labels. Thank you very much for your assistance and consideration.
\documentclass[12pt,letterpaper]{article}
\usepackage{circuitikz}
\begin{document}
\begin{circuitikz} \draw
(0,0) node[xor port] (g7) {$g_7$}
(0,2) node[xor port] (g6) {$g_6$}
(0,4) node[xor port] (g5) {$g_5$}
(0,6) node[xor port] (g4) {$g_4$}
(3,1) node[or port] (g3) {$g_3$}
(3,5) node[or port] (g2) {$g_2$}
(6,3) node[or port] (g1) {$g_1$}
(g4.out) to [short,l=${w_4}$] (g2.in 1)
(g5.out) to [short,l=${w_5}$] (g2.in 2)
(g6.out) to [short,l=${w_6}$] (g3.in 1)
(g7.out) to [short,l=${w_7}$] (g3.in 2)
(g2.out) to [short,l=${w_2}$] (g1.in 1)
(g3.out) to [short,l=${w_3}$] (g1.in 2)
(g1.out) node[anchor=west] {$output$}
(g4.in 1) node[anchor=east] {$a_3$}
(g4.in 2) node[anchor=east] {$b_3$}
(g5.in 1) node[anchor=east] {$a_2$}
(g5.in 2) node[anchor=east] {$b_2$}
(g6.in 1) node[anchor=east] {$a_1$}
(g6.in 2) node[anchor=east] {$b_1$}
(g7.in 1) node[anchor=east] {$a_0$}
(g7.in 2) node[anchor=east] {$b_0$}
;\end{circuitikz}
\end{document}
You can place a label on a line by adding a node. See section 17.8 (Placing Nodes on a Line or Curve Explicitly) of the pgf/tikz manual.
\documentclass[12pt,letterpaper]{article}
\usepackage{circuitikz}
\begin{document}
\begin{circuitikz} \draw
(0,0) node[xor port] (g7) {$g_7$}
(0,2) node[xor port] (g6) {$g_6$}
(0,4) node[xor port] (g5) {$g_5$}
(0,6) node[xor port] (g4) {$g_4$}
(3,1) node[or port] (g3) {$g_3$}
(3,5) node[or port] (g2) {$g_2$}
(6,3) node[or port] (g1) {$g_1$}
(g4.out) -| (g2.in 1) node[midway, above] {$w_4$}
(g5.out) -| (g2.in 2) node[midway, below] {$w_5$}
(g6.out) -| (g3.in 1) node[midway, above] {$w_6$}
(g7.out) -| (g3.in 2) node[midway, below] {$w_7$}
(g2.out) -| (g1.in 1) node[midway, above] {$w_2$}
(g3.out) -| (g1.in 2) node[midway, below] {$w_3$}
(g1.out) node[anchor=west] {$output$}
(g4.in 1) node[anchor=east] {$a_3$}
(g4.in 2) node[anchor=east] {$b_3$}
(g5.in 1) node[anchor=east] {$a_2$}
(g5.in 2) node[anchor=east] {$b_2$}
(g6.in 1) node[anchor=east] {$a_1$}
(g6.in 2) node[anchor=east] {$b_1$}
(g7.in 1) node[anchor=east] {$a_0$}
(g7.in 2) node[anchor=east] {$b_0$}
;\end{circuitikz}
\end{document}
In this example I used midway, but there are other keys to fine tune the position of the label.
• I didn't consider adding a node, though now that you demonstrated it, that seems intuitive. Thank you for citing the documentation concerning it too. – Ken Goss Jul 4 '17 at 16:13
You can \draw lines with |- and -|.
Here is an extract of your example:
\documentclass[12pt,letterpaper]{article}
\usepackage{circuitikz}
\begin{document}
\begin{circuitikz} \draw
(0,4) node[xor port] (g5) {$g_5$}
(0,6) node[xor port] (g4) {$g_4$}
(3,5) node[or port] (g2) {$g_2$}
(g4.in 1) node[anchor=east] {$a_3$}
(g4.in 2) node[anchor=east] {$b_3$}
(g5.in 1) node[anchor=east] {$a_2$}
(g5.in 2) node[anchor=east] {$b_2$}
(g4.out) |- node[above right]{${w_4}$} (g2.in 1)
(g5.out) |- node[below right]{${w_3}$} (g2.in 2)
;
\end{circuitikz}
\end{document} | {"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": 0.7943394184112549, "perplexity": 23401.523838140973}, "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-2019-51/segments/1575540525598.55/warc/CC-MAIN-20191209225803-20191210013803-00345.warc.gz"} |
http://pyrcel.readthedocs.io/en/latest/install.html | Installation¶
Coming soon!
From PyPI¶
If you already have all the dependencies satisfied, then you can install the latest release from PyPI by using pip:
$pip install pyrcel From source code¶ To grab and build the latest bleeding-edge version of the model, you should use pip and point it to the source code repository on github: $ pip install git+git://github.com/darothen/pyrcel.git
This should automatically build the necessary Cython modules and export the code package to your normal package installation directory. If you wish to simply build the code and run it in place, clone the repository, navigate to it in a terminal, and invoke the build command by hand:
$python setup.py build_ext --inplace This should produce the compiled file parcel_aux.so in the model package. You can also install the code from the cloned source directory by invoking pip install from within it; this is useful if you’re updating or modifying the model, since you can install an “editable” package which points directly to the git-monitored code: $ cd path/to/pyrcel/
$pip install -e . Dependencies¶ This code was originally written for Python 2.7, and then futurized to Python 3.3+ with hooks for backwards compatibility. By far, the simplest way to run this code is to grab a scientific python distribution, such as Anaconda. This code should work out-of-the box with almost all dependencies filled (exception being numerical solvers) on a recent version (1.2+) of this distribution. To facilitate this, conda environments for Python versions 2.7 and 3.5+ are provided in the pyrcel/ci directory. Necessary dependencies¶ Note As of version 1.2.0, the model integration components are being re-written and only the CVODE interface is exposed. As such, Assimulo is temporarily a core and required dependency; in the future the other solvers will be re-enabled. You should first try to install Assimulo via conda $ conda install -c conda-forge assimulo
since this will automatically take care of obtaining necessary compiled dependencies like sundials. However, for best results you may want to manually install Assimulo, since the conda-forge recipe may default to a sundials/OpenBLAS combination which could degare the performance of the model.
Testing¶
A nose test-suite is under construction. To check that your model is configured and running correctly, you copy and run the notebook corresponding to the basic run example, or run the command-line interface version of the model with the pre-packed simple run case:
$cd path/to/pyrcel/$ ./run_parcel examples/simple.yml
Bugs / Suggestions¶
The code has an issue tracker on github and I strongly encourage you to note any problems with the model there, such as typos or weird behavior and results. Furthermore, I’m looking for ways to expand and extend the model, so if there is something you might wish to see added, please note it there or send me an e-mail. The code was written in such a way that it should be trivial to add physics in a modular fashion. | {"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": 0.24624775350093842, "perplexity": 2033.6577304892178}, "config": {"markdown_headings": false, "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-2018-30/segments/1531676588972.37/warc/CC-MAIN-20180715203335-20180715223312-00021.warc.gz"} |
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Mathematica 837 rep 814 Programming Puzzles & Code Golf 181 rep 11 Mathematics 175 rep 9 Physics 165 rep 4 Area 51 151 rep 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": 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": 0.2530592679977417, "perplexity": 9757.875653071256}, "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-2015-32/segments/1438042992543.60/warc/CC-MAIN-20150728002312-00096-ip-10-236-191-2.ec2.internal.warc.gz"} |
https://getrevising.co.uk/revision-cards/as_physics_unit_2 | # AS PHYSICS UNIT 2
Notes for UNIT 2 AS PHYSICS
HideShow resource information
## Mechanics Basics
SCALARS - magnitude e.g. speed (m/s)
VECTOR - magnitude + direction e.g. velocity (...m/s bearing North)
Resolving means involving the big P - (Pythagoras) par exemple: if the angle is unknown but one has the 2 side values (adjacent and opposite) then you can work out the resultant value by using.... and work out the angle by using SOH CAH TOA
'Simples'
1 of 4
## SUVAT Equations (motion avec constant acceleration
v = u + at
v2 = u2 + 2as
s = ut + ½ at2
s = ½ (u + v)t
Voila, c'est facile! Remember these (and what the symbols mean) and ensure you can rearrange them. Do these tasks my young padawan and the path to success will become clear.
2 of 4
## Free Fall and Projectile Vomi...
Instance Uno - No Initial Velocity (tis just a'fallin) g = a = -9.81
s = ½gt2 v = gt and s = vt/2
Instance Two - Initial Velocity Upwards (thrown into air) The equations are normal SUVAT ones
Instance Drei - Thrown Downwards. The downwards velocity is minus and a = minus but the rest is all SUVAT..y
When doing questions related to 'blah blah is fired at blah blah m/s, blah blah m above the ground. How long does blah blah take to hit the ground and how far does blah blah travel?' ensure that you think in terms of vertical motion and horizontal motion as two separate calculations.
3 of 4
## G to the R to the A to the P to the H to the S!!!
LOOK IN REVISION GUIDE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
That is all
4 of 4 | {"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": 0.9010162949562073, "perplexity": 4081.2706096527754}, "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-2016-44/segments/1476988722459.85/warc/CC-MAIN-20161020183842-00377-ip-10-171-6-4.ec2.internal.warc.gz"} |
https://zbmath.org/?q=ci%3A1146.11057 | ×
# zbMATH — the first resource for mathematics
On the quaternionic $$p$$-adic $$L$$-functions associated to Hilbert modular eigenforms. (English) Zbl 1253.11088
Int. J. Number Theory 8, No. 4, 1005-1039 (2012); erratum ibid. 12, No. 1, 305-311 (2016).
The author constructs $$p$$-adic $$L$$-functions associated to cuspidal Hilbert modular eigenforms of parallel weight two in certain dihedral or anticyclotomic extensions. The construction generalizes those of M. Bertolini and H. Darmon [Invent. Math. 126, No. 3, 413–456 (1996; Zbl 0882.11034); Ann. Math. (2) 162, No. 1, 1–64 (2005; Zbl 1093.11037)] in the ordinary case, as well as constructions of H. Darmon and A. Iovita [J. Inst. Math. Jussieu 7, No. 2, 291–325 (2008; Zbl 1146.11057)] and R. Pollack [Duke Math. J. 118, No. 3, 523–558 (2003; Zbl 1074.11061)] in the supersingular case. The proof uses the refinement of Waldspurger’s theorem, given by X. Yuan, S. Zhang and W. Zhang [Heights of CM points. I: Gross-Zagier formula, preprint, to appear in Annals of Mathematical Studies, Princeton University Press].
The author also gives an expression for the Iwasawa $$p$$-invariant associated to the constructed $$p$$-adic $$L$$-functions (Theorem 4.14) following the method of V. Vatsal [Duke Math. J. 116, No. 2, 219–261 (2003; Zbl 1065.11048)].
The last section contains a conjectural non-vanishing criterion of B. Howard type for these $$p$$-adic $$L$$-functions (compare [J. Reine Angew. Math. 597, 1–25 (2006; Zbl 1127.11072); Theorem 3.2.3(c)]. This criterion, if satisfied, can be used to reduce the associated Iwasawa main conjecture to a certain non-triviality criterion for families of $$p$$-adic $$L$$-functions (Lemma 5.3).
##### MSC:
11M38 Zeta and $$L$$-functions in characteristic $$p$$ 11F41 Automorphic forms on $$\mbox{GL}(2)$$; Hilbert and Hilbert-Siegel modular groups and their modular and automorphic forms; Hilbert modular surfaces 11G40 $$L$$-functions of varieties over global fields; Birch-Swinnerton-Dyer conjecture 11R23 Iwasawa theory
Full Text:
##### References:
[1] DOI: 10.1007/s002220050105 · Zbl 0882.11034 [2] DOI: 10.4007/annals.2005.162.1 · Zbl 1093.11037 [3] Bourbaki N., Actualities Scientifiques et Industrielles 1314, in: Algebre Commutative, Chapitre 7: Diviseurs (1965) [4] DOI: 10.1017/CBO9780511721267.005 [5] Darmon H., J. Inst. Math. Jussieu 7 pp 291– [6] DOI: 10.1007/BF01231768 · Zbl 0847.11025 [7] Garrett P. B., Holomorphic Hilbert Modular Forms (1990) · Zbl 0685.10021 [8] Goren E., Lectures on Hilbert Modular Varieties and Modular Forms (2001) · Zbl 1066.11018 [9] DOI: 10.1215/S0012-7094-04-12411-X · Zbl 1068.11071 [10] Howard B., J. Reine Angew. Math. 597 pp 1– [11] Jacquet H., Lecture Notes in Mathematics 278, in: Automorphic Forms on GL(2) (1970) · Zbl 0236.12010 [12] DOI: 10.1112/S0010437X08003813 · Zbl 1247.11071 [13] DOI: 10.1215/S0012-7094-03-11835-9 · Zbl 1074.11061 [14] Rajaei A., J. Reine Angew. Math. 537 pp 35– [15] Saito H., Compos. Math. 85 pp 99– [16] DOI: 10.1215/S0012-7094-78-04529-5 · Zbl 0394.10015 [17] DOI: 10.2307/2374441 · Zbl 0532.12015 [18] van der Geer G., Hilbert Modular Surfaces (1980) · Zbl 0634.14022 [19] DOI: 10.1007/s002220100183 · Zbl 1119.11035 [20] DOI: 10.1215/S0012-7094-03-11622-1 · Zbl 1065.11048 [21] Vigneras M.-F., Lecture Notes in Mathematics 800, in: Arithmétique des Algèbres des Quaternions (1980) [22] Waldspurger J.-P., Compos. Math. 54 pp 173–
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching. | {"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": 0.31549009680747986, "perplexity": 3403.479127956646}, "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/1631780057424.99/warc/CC-MAIN-20210923135058-20210923165058-00513.warc.gz"} |
https://www.tutorialspoint.com/weight-biased-leftist-trees-in-data-structure | # Weight-Biased Leftist Trees in Data Structure
Data StructureAnalysis of AlgorithmsAlgorithms
Here we will see another variation of Leftist Tree. Here we will consider the number of nodes in a subtree, rather than the length of a shortest path for root to external node. Here we will define the weight w(x) of node x, to be the number of internal nodes in the subtree with root x. If x is an external node, then the weight is 0. If x is internal node, then the weight is one more than the sum of weights of its children.
Here is an example of Weight Biased Leftist Tree (WBLT) −
Suppose the Binary tree is like this −
If we calculate w(x) values for each node, it will be like this −
Now the definition of WBLT is like −
A binary tree is called Weight Balanced Leftist Tree if and only if, at every internal node the w(x) of left child is greater than or equal to the w(x) of the right child. A max (min) WBLT is a max (min) tree that is also a WBLT.
Published on 11-Aug-2020 07:14:35 | {"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": 0.8172263503074646, "perplexity": 742.9311019854379}, "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/1634323585380.70/warc/CC-MAIN-20211021005314-20211021035314-00460.warc.gz"} |
http://www.ctanujit.in/2013/06/tricks-for-isi-entrance-exam.html | ## Pages
### Tricks for solving problems of ISI Entrance exam
MATH-TRICK-6
This is on Functional Equations explained through some solved problems.
Result:- If f is a continuous function that satisfies f(x+y)=f(x)+f(y) for all x,y, then f(x)=xf(1).
Proof:- (Hints)
We know that if f is a function satisfying f(x+y)=f(x)+f(y) for all x,y then f(x)=kx ,where k is a constant.
[To show this, Check the differentiability first.Then
f'(x)=Lt{f(x+h)-f}/h ,where h->0.
f'(x)=Lt {f(h)/h} where h->0
= f'(0)=k(say).
Then integrate both sides, you will get f(x)=kx+c ------(1)
Put x=y=0 in the given equation,then f(0)=0.
From (1), c=0, i.e. f(x)=kx. ]
Here f(1)=k ,so f(x)=kx=xf(1).
Problem:- [ISI Sample paper] Let g be a continuous function with g(1)=1 such that
g(x+y)=5g(x)g(y)
for all x,y. Find g(x).
Sol:- g(x+y)=5g(x)g(y)
5g(x+y)=5g(x)5g(y), taking log bothsides
=> log[5g(x+y)]=log[5g(x)] + log[5g(y)]
=> f(x+y)=f(x)+f(y), taking f(x+y)=log[5g(x+y)]
=> f(x)= xf(1) [By the above result]
So, log[5g(x)]=xlog[5g(1)]
=> 5g(x) = 5^x ,since g(1)=1 (given)
=> g(x) = 5^{x-1} . | {"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": 0.9707667827606201, "perplexity": 18903.70936200659}, "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-2021-43/segments/1634323587623.1/warc/CC-MAIN-20211025030510-20211025060510-00262.warc.gz"} |
https://www.physicsforums.com/threads/can-gamma-function-be-used-to-integrate-factorials.45088/ | # Can Gamma Function be used to Integrate Factorials?
1. Sep 28, 2004
### Hyperreality
By definite integral, gamma function can be defined as
$$\Gamma(z)= \int_{0}^{\infty} t^{z-1}e^{-t} dt$$
I've learnt some properties of Gamma function but my lecturer didn't tell us the domain of Gamma function. (I'm assuming it is defined for all non-negative real numbers).
I thought of this problem a while ago:
We know that
$$\sum_{n=0}^\infty \frac{x^n}{n!} = \lim_{n\rightarrow\infty} (1+x/n)^n=e^1$$
My question is, is there a numerical solution to
$$\int_{0}^{\infty}\frac{1}{x!} dx$$
where x is an non-negative real number over a continuous interval in terms of gamma function?
Last edited: Sep 28, 2004
2. Sep 29, 2004
### Zurtex
I've tried looking this up but to no avail sorry. I think you will find that the Gamma function is definied for all complex numbers except negative real integers (but obviously depends on context of what you are using it for to what you definie it for). But something worth noting is that:
$$x! = \Gamma (x + 1)$$ if and only if $$x \epsilon \mathbb{Z}, x \geq 0$$
So your question doesn't really make much sense, what you want to be asking is this:
$$\int_0^{\infty} \frac{1}{\Gamma (x + 1)}dx$$
Otherwise quite simply as x! is just a series of points:
$$\int_0^{\infty} \frac{1}{x!}dx = 0$$
P.S Err, also:
$$\sum_{n=0}^\infty \frac{x^n}{n!} \neq e^1$$
I think you will find that:
$$\sum_{n=0}^\infty \frac{x^n}{n!} = e^x$$
Last edited: Sep 29, 2004
3. Nov 9, 2008
### flouran
N! is just a series of points, where n is any whole number; whereas the Pi function can describe continuously. But there is a discrepancy; for instance, (1.5)! doesn't make sense in the traditional sense of the function, but it does according to the continuous Pi function. Thus, the integral of a factorial doesn't seem to make much sense. Besides, it wouldn't prove too useful anyways because in most mathematics, n! is presented as a constant and thus need not be integrated as a function over n.
Last edited: Nov 9, 2008
4. Nov 11, 2008
### yasiru89
You might try the Weierstrass product representation and have a go at
$$\int_0^{+\infty} \frac{1}{\Pi(t)}dt$$
, where [itex]\Pi(t) = \Gamma(t + 1)[/tex], but a nice answer probably won't result. You might try to get suitable Riemann sums at integer points on a general interval and try to bound the integral though.
Similar Discussions: Can Gamma Function be used to Integrate Factorials? | {"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": 0.97230464220047, "perplexity": 644.1930901594666}, "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-2017-09/segments/1487501171163.39/warc/CC-MAIN-20170219104611-00158-ip-10-171-10-108.ec2.internal.warc.gz"} |
https://math.stackexchange.com/questions/3270445/can-withdrawal-of-the-power-set-axiom-enable-absoluteness-for-set-size-statement | # Can withdrawal of the Power set axiom enable absoluteness for set size statements?
If we look to models of $$\small \sf ZFC$$ we can have two transitive models $$N,M$$ such that for some formula $$\phi$$ in the language of $$\small \sf ZFC$$ we have:
$$\forall \mathcal M ([\mathcal M\models ZFC] \to \mathcal M\models \exists!x (\phi))$$
$$M\models \exists x (\phi \land |x| = \kappa)$$
$$N\models \exists x (\phi \land |x| \neq \kappa)$$,
for example left $$\phi$$ be $$x=P(\omega)$$ and let $$\kappa= \omega_1$$. I'll refer to the above as "size statements about some sets theorized to uniquely exist by $$\small \sf ZFC$$, are not absolute".
Now examine this theory, the question is:
Can we have the above situation raised with it also? In other words, can it theorize the unique existence of some sets the size statements about which are not absolute?
Yes. Surely we can, under reasonable assumptions, find two transitive models $$M, N$$ of this theory, one of which (say $$M$$) has a powerset of $$\omega$$ and the other does not. Let $$\varphi(x)$$ be the formula which asserts that $$x$$ is $$\mathcal P(\omega)$$ if it exists and $$\emptyset$$ else. The given theory proves that there is a unique $$x$$ which satisfies $$\varphi$$. But now the respective witnesses in $$M$$ and $$N$$ have vastly different sizes. A variation of this trick works (essentially) whenever the given theory is incomplete (given that the question even makes sense for that theory). | {"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": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 22, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.95991051197052, "perplexity": 270.2514855009844}, "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/1581875145747.6/warc/CC-MAIN-20200223062700-20200223092700-00505.warc.gz"} |
https://worldwidescience.org/topicpages/l/line+region+kinematics.html | Sample records for line region kinematics
1. The broad line region of AGN: Kinematics and physics
Directory of Open Access Journals (Sweden)
Popović L.Č.
2006-01-01
Full Text Available In this paper a discussion of kinematics and physics of the Broad Line Region (BLR is given. The possible physical conditions in the BLR and problems in determination of the physical parameters (electron temperature and density are considered. Moreover, one analyses the geometry of the BLR and the probability that (at least a fraction of the radiation in the Broad Emission Lines (BELs originates from a relativistic accretion disk.
2. Imaging spectrophotometry of ionized gas in NGC 1068. I - Kinematics of the narrow-line region
Science.gov (United States)
Cecil, Gerald; Bland, Jonathan; Tully, R. Brent
1990-01-01
The kinematics of collisionally excited forbidden N II 6548, 6583 across the inner 1 arcmin diameter of the nearby Seyfert galaxy NGC 1068 is mapped using an imaging Fabry-Perot interferometer and low-noise CCD. The stack of monochromatic images, which spatially resolved the high-velocity gas, was analyzed for kinematic and photometric content. Profiles agree well with previous long-slit work, and their complete spatial coverage makes it possible to constrain the gas volume distribution. It is found that the narrow-line region is distributed in a thick center-darkened, line-emitting cylinder that envelopes the collimated radio jet. Three distinct kinematic subsystems, of which the cylinder is composed, are discussed in detail. Detailed behavior of the emission-line profiles, at the few points in the NE quadrant with simple kinematics, argues that the ionized gas develops a significant component of motion perpendicular to the jet axis.
3. A study of the structure and kinematics of the narrow-line region in Seyfert galaxies
International Nuclear Information System (INIS)
Veilleux, S.
1989-01-01
The results of a high resolution study of the narrow emission line profiles of 16 Seyfert galaxies are presented. It is shown that the line profile parameters published in earlier low resolution studies are sometimes strongly influenced by resolution effects. In spite of these important systematic errors, many of the results derived from low resolution data are confirmed in the high resolution data. The narrow line profiles of Seyfert galaxies have a stronger base relative to core than a Gaussian. Most of the emission lines present a blueward asymmetry in the lower portion of their profile. In some galaxies, the line widths and/or line asymmetries are correlated with the ionization potential and/or critical density of the lines. There is a weak correlation between the line asymmetry and the dust content of the narrow line region (NLR). The large scatter in this relation, the absence of a similar correlation in Seyfert 1 to 1.5 galaxies, and the presence of a blue asymmetry in galaxies with dustfree line-emitting regions suggest that dust obscuration is not the only mechanism responsible for the line asymmetry in active galaxies. An optically-thick disk close to the nucleus is proposed as the other source of line asymmetry. An important result is that the host galaxy is probably playing a role in the kinematics of some of the gas in the NLR. A multicomponent model of the NLR is proposed to explain these results
4. Outflow Kinematics Manifested by the Hα Line: Gas Outflows in Type 2 AGNs. IV
Energy Technology Data Exchange (ETDEWEB)
Kang, Daeun; Woo, Jong-Hak; Bae, Hyun-Jin, E-mail: woo@astro.snu.ac.kr [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)
2017-08-20
Energetic ionized gas outflows driven by active galactic nuclei (AGNs) have been studied as a key phenomenon related to AGN feedback. To probe the kinematics of the gas in the narrow-line region, [O iii] λ 5007 has been utilized in a number of studies showing nonvirial kinematic properties due to AGN outflows. In this paper, we statistically investigate whether the H α emission line is influenced by AGN-driven outflows by measuring the kinematic properties based on the H α line profile and comparing them with those of [O iii]. Using the spatially integrated spectra of ∼37,000 Type 2 AGNs at z < 0.3 selected from the Sloan Digital Sky Survey DR7, we find a nonlinear correlation between H α velocity dispersion and stellar velocity dispersion that reveals the presence of the nongravitational component, especially for AGNs with a wing component in H α . The large H α velocity dispersion and velocity shift of luminous AGNs are clear evidence of AGN outflow impacts on hydrogen gas, while relatively smaller kinematic properties compared to those of [O iii] imply that the observed outflow effect on the H α line is weaker than the case of [O iii].
5. THE GREEN BANK TELESCOPE H II REGION DISCOVERY SURVEY. III. KINEMATIC DISTANCES
Energy Technology Data Exchange (ETDEWEB)
Anderson, L. D. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Bania, T. M. [Institute for Astrophysical Research, Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Balser, Dana S. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Rood, Robert T., E-mail: Loren.Anderson@mail.wvu.edu [Astronomy Department, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903-0818 (United States)
2012-07-20
Using the H I emission/absorption method, we resolve the kinematic distance ambiguity and derive distances for 149 of 182 (82%) H II regions discovered by the Green Bank Telescope H II Region Discovery Survey (GBT HRDS). The HRDS is an X-band (9 GHz, 3 cm) GBT survey of 448 previously unknown H II regions in radio recombination line and radio continuum emission. Here, we focus on HRDS sources from 67 Degree-Sign {>=} l {>=} 18 Degree-Sign , where kinematic distances are more reliable. The 25 HRDS sources in this zone that have negative recombination line velocities are unambiguously beyond the orbit of the Sun, up to 20 kpc distant. They are the most distant H II regions yet discovered. We find that 61% of HRDS sources are located at the far distance, 31% at the tangent-point distance, and only 7% at the near distance. 'Bubble' H II regions are not preferentially located at the near distance (as was assumed previously) but average 10 kpc from the Sun. The HRDS nebulae, when combined with a large sample of H II regions with previously known distances, show evidence of spiral structure in two circular arc segments of mean Galactocentric radii of 4.25 and 6.0 kpc. We perform a thorough uncertainty analysis to analyze the effect of using different rotation curves, streaming motions, and a change to the solar circular rotation speed. The median distance uncertainty for our sample of H II regions is only 0.5 kpc, or 5%. This is significantly less than the median difference between the near and far kinematic distances, 6 kpc. The basic Galactic structure results are unchanged after considering these sources of uncertainty.
6. Radio recombination lines from H II regions
International Nuclear Information System (INIS)
Silverglate, P.R.
1978-01-01
Radio recombination lines have been observed from forty-six H II regions. The Arecibo 1000-foot radio telescope was used to provide high sensitivity and high angular resolution at 1400 MHz (gain approx. 7.7 0 K/Jy, HPBW = 3:2) and 2372 MHZ (gain approx. 6.3 0 K/Jy, HPBW = 2'). Observations were made at 1400 MHz in the frequency switching mode, and at 2372 MHz in the total power mode. Gaussians were fit to be observed lines to derive velocities, line widths, and line temperatures. From the velocities kinematic distances were derived. For eleven sources H I absorption measurements were also made. The absorption spectra enabled the kinematic distance ambiguity to be resolved for some sources. The absorption spectra themselves were found to have extremely sharp, non-gaussian edges. One explanation for these is a model where the interstellar medium contains many H I cloudlets with T/sub s/less than or equal to 100 0 K and turbulent velocities less than or equal to 3 km/s. The H I absorption spectrum is then a superposition of many narrow gaussian profiles. It was also found from a comparison of H I absorption velocities with radio recombination line velocities that peculiar motions exist in the interstellar medium with velocities of up to 10 km/s. Using the measured line temperatures and continuum temperatures, estimates were desired of emission measures, electron temperatures, and electron densities, using a non-LTE analysis. Non-LTE effects were important only for the hottest and densest H II regions. The non-LTE calculations were checked through a comparison derivation of electron temperatures using hydrogen beta lines
7. The emission-line regions in the nucleus of NGC 1313 probed with GMOS-IFU: a supergiant/hypergiant candidate and a kinematically cold nucleus
Science.gov (United States)
Menezes, R. B.; Steiner, J. E.
2017-04-01
NGC 1313 is a bulgeless nearby galaxy, classified as SB(s)d. Its proximity allows high spatial resolution observations. We performed the first detailed analysis of the emission-line properties in the nuclear region of NGC 1313, using an optical data cube obtained with the Gemini Multi-object Spectrograph. We detected four main emitting areas, three of them (regions 1, 2 and 3) having spectra typical of H II regions. Region 1 is located very close to the stellar nucleus and shows broad spectral features characteristic of Wolf-Rayet stars. Our analysis revealed the presence of one or two WC4-5 stars in this region, which is compatible with results obtained by previous studies. Region 4 shows spectral features (as a strong Hα emission line, with a broad component) typical of a massive emission-line star, such as a luminous blue variable, a B[e] supergiant or a B hypergiant. The radial velocity map of the ionized gas shows a pattern consistent with rotation. A significant drop in the values of the gas velocity dispersion was detected very close to region 1, which suggests that the young stars there were formed from this cold gas, possibly keeping low values of velocity dispersion. Therefore, although detailed measurements of the stellar kinematics were not possible (due to the weak stellar absorption spectrum of this galaxy), we predict that NGC 1313 may also show a drop in the values of the stellar velocity dispersion in its nuclear region.
8. Ionised gas kinematics in bipolar H II regions
Science.gov (United States)
Dalgleish, Hannah S.; Longmore, Steven N.; Peters, Thomas; Henshaw, Jonathan D.; Veitch-Michaelis, Joshua L.; Urquhart, James S.
2018-05-01
Stellar feedback plays a fundamental role in shaping the evolution of galaxies. Here we explore the use of ionised gas kinematics in young, bipolar H II regions as a probe of early feedback in these star-forming environments. We have undertaken a multi-wavelength study of a young, bipolar H II region in the Galactic disc, G316.81-0.06, which lies at the centre of a massive (˜103 M⊙) infrared-dark cloud filament. It is still accreting molecular gas as well as driving a ˜0.2 pc ionised gas outflow perpendicular to the filament. Intriguingly, we observe a large velocity gradient (47.81 ± 3.21 km s-1 pc-1) across the ionised gas in a direction perpendicular to the outflow. This kinematic signature of the ionised gas shows a reasonable correspondence with the simulations of young H II regions. Based on a qualitative comparison between our observations and these simulations, we put forward a possible explanation for the velocity gradients observed in G316.81-0.06. If the velocity gradient perpendicular to the outflow is caused by rotation of the ionised gas, then we infer that this rotation is a direct result of the initial net angular momentum in the natal molecular cloud. If this explanation is correct, this kinematic signature should be common in other young (bipolar) H II regions. We suggest that further quantitative analysis of the ionised gas kinematics of young H II regions, combined with additional simulations, should improve our understanding of feedback at these early stages.
9. Kinematic geometry of a line trajectory in spatial motion
Energy Technology Data Exchange (ETDEWEB)
Al-Ghefari, Reem A. [King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-Baky, Rashad A. [University of Assiut, Assiu (Egypt)
2015-09-15
This paper derives the equations of line-trajectory in spatial motion by means of the E. Study dual-line coordinates. A special emphasis goes to the second-order motion properties for deriving a new proof of the Disteli formulae. As an application concise explicit expressions of the inflection line congruence are directly obtained. Also, a new metric is developed and used to investigate the geometrical properties and kinematics of line trajectory as well as Disteli axis. Finally, a theoretical expressions of point trajectories with special values of velocity and acceleration, which can be considered as a form Euler-Savary equation, for spherical and planar motions are discussed.
10. New Constraints on Quasar Broad Absorption and Emission Line Regions from Gravitational Microlensing
Energy Technology Data Exchange (ETDEWEB)
Hutsemékers, Damien; Braibant, Lorraine; Sluse, Dominique [Institut d' Astrophysique et de Géophysique, Université de Liège, Liège (Belgium); Anguita, Timo [Departamento de Ciencias Fisicas, Universidad Andres Bello, Santiago (Chile); Goosmann, René, E-mail: hutsemekers@astro.ulg.ac.be [Observatoire Astronomique de Strasbourg, Université de Strasbourg, Strasbourg (France)
2017-09-29
Gravitational microlensing is a powerful tool allowing one to probe the structure of quasars on sub-parsec scale. We report recent results, focusing on the broad absorption and emission line regions. In particular microlensing reveals the intrinsic absorption hidden in the P Cygni-type line profiles observed in the broad absorption line quasar H1413+117, as well as the existence of an extended continuum source. In addition, polarization microlensing provides constraints on the scattering region. In the quasar Q2237+030, microlensing differently distorts the Hα and CIV broad emission line profiles, indicating that the low- and high-ionization broad emission lines must originate from regions with distinct kinematical properties. We also present simulations of the effect of microlensing on line profiles considering simple but representative models of the broad emission line region. Comparison of observations to simulations allows us to conclude that the Hα emitting region in Q2237+030 is best represented by a Keplerian disk.
11. New Constraints on Quasar Broad Absorption and Emission Line Regions from Gravitational Microlensing
Directory of Open Access Journals (Sweden)
Damien Hutsemékers
2017-09-01
Full Text Available Gravitational microlensing is a powerful tool allowing one to probe the structure of quasars on sub-parsec scale. We report recent results, focusing on the broad absorption and emission line regions. In particular microlensing reveals the intrinsic absorption hidden in the P Cygni-type line profiles observed in the broad absorption line quasar H1413+117, as well as the existence of an extended continuum source. In addition, polarization microlensing provides constraints on the scattering region. In the quasar Q2237+030, microlensing differently distorts the Hα and CIV broad emission line profiles, indicating that the low- and high-ionization broad emission lines must originate from regions with distinct kinematical properties. We also present simulations of the effect of microlensing on line profiles considering simple but representative models of the broad emission line region. Comparison of observations to simulations allows us to conclude that the Hα emitting region in Q2237+030 is best represented by a Keplerian disk.
12. Type 2 Active Galactic Nuclei with Double-peaked [O III] Lines. II. Single AGNs with Complex Narrow-line Region Kinematics are More Common than Binary AGNs
Science.gov (United States)
Shen, Yue; Liu, Xin; Greene, Jenny E.; Strauss, Michael A.
2011-07-01
Approximately 1% of low-redshift (z interpreted as either due to kinematics, such as biconical outflows and/or disk rotation of the narrow line region (NLR) around single black holes, or due to the relative motion of two distinct NLRs in a merging pair of AGNs. Here, we report follow-up near-infrared (NIR) imaging and optical slit spectroscopy of 31 double-peaked [O III] type 2 AGNs drawn from the Sloan Digital Sky Survey (SDSS) parent sample presented in Liu et al. The NIR imaging traces the old stellar population in each galaxy, while the optical slit spectroscopy traces the NLR gas. These data reveal a mixture of origins for the double-peaked feature. Roughly 10% of our objects are best explained by binary AGNs at (projected) kpc-scale separations, where two stellar components with spatially coincident NLRs are seen. ~50% of our objects have [O III] emission offset by a few kpc, corresponding to the two velocity components seen in the SDSS spectra, but there are no spatially coincident double stellar components seen in the NIR imaging. For those objects with sufficiently high-quality slit spectra, we see velocity and/or velocity dispersion gradients in [O III] emission, suggestive of the kinematic signatures of a single NLR. The remaining ~40% of our objects are ambiguous and will need higher spatial resolution observations to distinguish between the two scenarios. Our observations therefore favor the kinematics scenario with a single AGN for the majority of these double-peaked [O III] type 2 AGNs. We emphasize the importance of combining imaging and slit spectroscopy in identifying kpc-scale binary AGNs, i.e., in no cases does one of these alone allow an unambiguous identification. We estimate that ~0.5%-2.5% of the z ~ 150 km s-1. Based in part on observations obtained with the 6.5 m Magellan telescopes located at Las Campanas Observatory, Chile, and with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research
13. Extended Narrow-Line Region in Seyfert Galaxies
Energy Technology Data Exchange (ETDEWEB)
Congiu, Enrico [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Astronomical Observatory of Brera, National Institute for Astrophysics, Milan (Italy); Contini, Marcella [School of Physics and Astronomy, Tel Aviv University, Tel Aviv (Israel); Ciroi, Stefano; Cracco, Valentina [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Di Mille, Francesco [Las Campanas Observatory, La Serena (Chile); Berton, Marco [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Astronomical Observatory of Brera, National Institute for Astrophysics, Milan (Italy); Frezzato, Michele; La Mura, Giovanni; Rafanelli, Piero, E-mail: enrico.congiu@phd.unipd.it [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy)
2017-10-24
We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a) the contribution of shocks in ionizing the high velocity gas, (b) the complex kinematics showed by the profile of the emission lines, (c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.
14. Extended Narrow-Line Region in Seyfert Galaxies
International Nuclear Information System (INIS)
Congiu, Enrico; Contini, Marcella; Ciroi, Stefano; Cracco, Valentina; Di Mille, Francesco; Berton, Marco; Frezzato, Michele; La Mura, Giovanni; Rafanelli, Piero
2017-01-01
We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a) the contribution of shocks in ionizing the high velocity gas, (b) the complex kinematics showed by the profile of the emission lines, (c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.
15. A TALE OF TWO NARROW-LINE REGIONS: IONIZATION, KINEMATICS, AND SPECTRAL ENERGY DISTRIBUTIONS FOR A LOCAL PAIR OF MERGING OBSCURED ACTIVE GALAXIES
Energy Technology Data Exchange (ETDEWEB)
Hainline, Kevin N.; Hickox, Ryan C.; Chen, Chien-Ting; Carroll, Christopher M.; Jones, Mackenzie L.; Zervos, Alexandros S. [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Goulding, Andrew D. [Department Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
2016-05-20
We explore the gas ionization and kinematics, as well as the optical-IR spectral energy distributions for UGC 11185, a nearby pair of merging galaxies hosting obscured active galactic nuclei (AGNs), also known as SDSS J181611.72+423941.6 and J181609.37+423923.0 (J1816NE and J1816SW, z ≈ 0.04). Due to the wide separation between these interacting galaxies (∼23 kpc), observations of these objects provide a rare glimpse of the concurrent growth of supermassive black holes at an early merger stage. We use BPT line diagnostics to show that the full extent of the narrow-line emission in both galaxies is photoionized by an AGN, and confirm the existence of a 10 kpc-scale ionization cone in J1816NE, while in J1816SW the AGN narrow-line region is much more compact (1–2 kpc) and relatively undisturbed. Our observations also reveal the presence of ionized gas that nearly spans the entire distance between the galaxies, which is likely in a merger-induced tidal stream. In addition, we carry out a spectral analysis of the X-ray emission using data from XMM-Newton . These galaxies represent a useful pair to explore how the [O iii] luminosity of an AGN is dependent on the size of the region used to explore the extended emission. Given the growing evidence for AGN “flickering” over short timescales, we speculate that the appearances and impacts of these AGNs may change multiple times over the course of the galaxy merger, which is especially important given that these objects are likely the progenitors of the types of systems commonly classified as “dual AGNs.”.
16. The Kinematics of the Permitted C ii λ 6578 Line in a Large Sample of Planetary Nebulae
Energy Technology Data Exchange (ETDEWEB)
Richer, Michael G.; Suárez, Genaro; López, José Alberto; García Díaz, María Teresa, E-mail: richer@astrosen.unam.mx, E-mail: gsuarez@astro.unam.mx, E-mail: jal@astrosen.unam.mx, E-mail: tere@astro.unam.mx [Instituto de Astronomía, Universidad Nacional Autónoma de México, Ensenada, Baja California (Mexico)
2017-03-01
We present spectroscopic observations of the C ii λ 6578 permitted line for 83 lines of sight in 76 planetary nebulae at high spectral resolution, most of them obtained with the Manchester Echelle Spectrograph on the 2.1 m telescope at the Observatorio Astronómico Nacional on the Sierra San Pedro Mártir. We study the kinematics of the C ii λ 6578 permitted line with respect to other permitted and collisionally excited lines. Statistically, we find that the kinematics of the C ii λ 6578 line are not those expected if this line arises from the recombination of C{sup 2+} ions or the fluorescence of C{sup +} ions in ionization equilibrium in a chemically homogeneous nebular plasma, but instead its kinematics are those appropriate for a volume more internal than expected. The planetary nebulae in this sample have well-defined morphology and are restricted to a limited range in H α line widths (no large values) compared to their counterparts in the Milky Way bulge; both these features could be interpreted as the result of young nebular shells, an inference that is also supported by nebular modeling. Concerning the long-standing discrepancy between chemical abundances inferred from permitted and collisionally excited emission lines in photoionized nebulae, our results imply that multiple plasma components occur commonly in planetary nebulae.
17. Extended Narrow-Line Region in Seyfert Galaxies
Directory of Open Access Journals (Sweden)
Enrico Congiu
2017-10-01
Full Text Available We present our recent results about the extended narrow-line region (ENLR of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212 obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1 galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a the contribution of shocks in ionizing the high velocity gas, (b the complex kinematics showed by the profile of the emission lines, (c the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.
18. Clues to Quasar Broad Line Region Geometry and Kinematics
DEFF Research Database (Denmark)
Vestergaard, Marianne; Wilkes, B. J.; Barthel, P. D.
2000-01-01
width to show significant inverse correlations with the fractional radio core-flux density, R, the radio axis inclination indicator. Highly inclined systems have broader line wings, consistent with a high-velocity field perpendicular to the radio axis. By contrast, the narrow line-core shows...... no such relation with R, so the lowest velocity CIV-emitting gas has an inclination independent velocity field. We propose that this low-velocity gas is located at higher disk-altitudes than the high-velocity gas. A planar origin of the high-velocity CIV-emission is consistent with the current results...... and with an accretion disk-wind emitting the broad lines. A spherical distribution of randomly orbiting broad-line clouds and a polar high-ionization outflow are ruled out....
19. Kinematics of current region fragmentation in semi-inclusive deeply inelastic scattering
Energy Technology Data Exchange (ETDEWEB)
Boglione, M., E-mail: elena.boglione@to.infn.it [Dipartimento di Fisica, Università di Torino, INFN - Sezione Torino, Via P. Giuria 1, 10125 Torino (Italy); Collins, J., E-mail: jcc8@psu.edu [Department of Physics, Penn State University, University Park, PA 16802 (United States); Gamberg, L., E-mail: lpg10@psu.edu [Science Division, Penn State University Berks, Reading, PA 19610 (United States); Gonzalez-Hernandez, J.O., E-mail: jogh@jlab.org [Department of Physics, Old Dominion University, Norfolk, VA 23529 (United States); Theory Center, Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Rogers, T.C., E-mail: trogers@odu.edu [Department of Physics, Old Dominion University, Norfolk, VA 23529 (United States); Theory Center, Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Sato, N., E-mail: nsato@jlab.org [Theory Center, Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)
2017-03-10
Different kinematical regions of semi-inclusive deeply inelastic scattering (SIDIS) processes correspond to different underlying partonic pictures, and it is important to understand the transition between them. We find criteria in semi-inclusive deeply inelastic scattering (SIDIS) for identifying the current fragmentation region — the kinematical region where a factorization picture with fragmentation functions is appropriate, especially for studies of transverse-momentum-dependent (TMD) functions. This region is distinguished from the central (soft) and target fragmentation regions. The basis of our argument is in the errors in approximations used in deriving factorization. As compared with previous work, we show that it is essential to take account of the transverse momentum of the detected hadron, and we find a much more restricted range for genuine current fragmentation. We show that it is important to develop an extended factorization formulation to treat hadronization in the central region, as well as the current and target fragmentation regions, and to obtain a unified formalism spanning all rapidities for the detected hadron.
20. Clues to quasar broad-line region geometry and kinematics
NARCIS (Netherlands)
Vestergaard, M; Wilkes, BJ; Barthel, PD
2000-01-01
We present evidence that the high-velocity C IV lambda 1549 emission-line gas of radio-loud quasars may originate in a disklike configuration, in close proximity to the accretion disk often assumed to emit the low-ionization lines. For a sample of 36 radio-loud z approximate to 2 quasars, we find
1. Observations of far-infrared line profiles in the Orion-KL region
International Nuclear Information System (INIS)
Crawford, M.K.; Lugten, J.B.; Fitelson, W.; Genzel, R.; Melnick, G.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)
1986-01-01
Measurements of several far-infrared emission line profiles in the Orion-KL region are reported. The emission from the CO, OH, and forbidden O I emission lines toward the BN-KL and H2 peak 1 positions probably comes from dense, hot molecular gas in the Orion-KL shock. The CO and forbidden O I lines have similar profiles, suggesting that the high-velocity forbidden O I emission also arises in magnetohydrodynamic cloud shocks. The velocity centroids of the lines are somewhat blueshifted. The far-infrared data thus support the interpretation that the blue asymmetry of the H2 2 micron lines is not mainly due to differential dust extinction, but rather to the kinematics and geometry of the shocked gas in the Orion-KL outflow. The forbidden O I and CO lines, however, have significantly less extreme blueshifted emission than the H2 lines. Both the forbidden O I 63 micron and forbidden C II 158 micron lines have features strongly supporting a common origin near the surface of the Orion molecular cloud. 28 references
2. SPATIALLY RESOLVED KINEMATICS OF THE CENTRAL REGIONS OF M83: HIDDEN MASS SIGNATURES AND THE ROLE OF SUPERNOVAE
Energy Technology Data Exchange (ETDEWEB)
Piqueras Lopez, J.; Colina, L. [Centro de Astrobiologia, INTA-CSIC (Spain); Davies, R.; Orban de Xivry, G., E-mail: piqueraslj@cab.inta-csic.es [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, 85741 Garching (Germany)
2012-06-10
The barred grand-design spiral M83 (NGC 5236) is one of the most studied galaxies given its proximity, orientation, and particular complexity. Nonetheless, many aspects of the central regions remain controversial, conveying our limited understanding of the inner gas and stellar kinematics, and ultimately of the nucleus evolution. In this work, we present AO VLT-SINFONI data of its central {approx}235 Multiplication-Sign 140 pc with an unprecedented spatial resolution of {approx}0.2 arcsec, corresponding to {approx}4 pc. We have focused our study on the distribution and kinematics of the stars and the ionized and molecular gas by studying the Pa{alpha} and Br{gamma} emission in detail, the H{sub 2} 1-0S(1) line at 2.122 {mu}m, and the [Fe II] line at 1.644 {mu}m, together with the CO absorption bands at 2.293 {mu}m and 2.323 {mu}m. Our results reveal a complex situation where the gas and stellar kinematics are totally unrelated. Supernova explosions play an important role in shaping the gas kinematics, dominated by shocks and inflows at scales of tens of parsecs that make them unsuitable to derive general dynamical properties. We propose that the location of the nucleus of M83 is unlikely to be related to the off-center 'optical nucleus'. The study of the stellar kinematics reveals that the optical nucleus is a gravitationally bound massive star cluster with M{sub dyn} = (1.1 {+-} 0.4) Multiplication-Sign 10{sup 7} M{sub Sun }, formed by a past starburst. The kinematic and photometric analysis of the cluster yield that the stellar content of the cluster is well described by an intermediate age population of log T(yr) = 8.0 {+-} 0.4, with a mass of M* {approx_equal} (7.8 {+-} 2.4) Multiplication-Sign 10{sup 6} M{sub Sun }.
3. Diagnosing the Kinematics of the Tori in Active Galactic Nuclei with the Velocity-resolved Reverberation Mapping of the Narrow Iron K α Line
Energy Technology Data Exchange (ETDEWEB)
Liu Yuan; Li Xiaobo, E-mail: liuyuan@ihep.ac.cn, E-mail: lixb@ihep.ac.cn [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918-3, Beijing 100049 (China)
2017-07-20
The properties of the dusty tori in active galactic nuclei (AGNs) have been investigated in detail, mainly focusing on the geometry and components; however, the kinematics of the torus are still not clear. The narrow iron K α line at 6.4 keV is thought to be produced by the X-ray reflection from the torus. Thus, the velocity-resolved reverberation mapping of it is able to constrain the kinematics of the torus. Such effort is limited by the spectral resolution of current charged coupled device (CCD) detectors and should be possible with the microcalorimeter on the next generation X-ray satellite. In this paper, we first construct the response functions of the torus under a uniform inflow, a Keplerian rotation, and a uniform outflow. Then the energy-dependent light curve of the narrow iron K α line is simulated according to the performance of the X-ray Integral Field Unit in Athena. Finally, the energy-dependent cross-correlation function is calculated to reveal the kinematic signal. According to our results, 100 observations with 5 ks exposure of each are sufficient to distinguish the above three velocity fields. Although the real geometry and velocity field of the torus could be more complex than we assumed, the present result proves the feasibility of the velocity-resolved reverberation mapping of the narrow iron K α line. The combination of the dynamics of the torus with those of the broad-line region and the host galaxy is instructive for the understanding of the feeding and feedback process of AGNs.
4. KINEMATICS OF THE CO GAS IN THE INNER REGIONS OF THE TW Hya DISK
Energy Technology Data Exchange (ETDEWEB)
Rosenfeld, Katherine A.; Qi Chunhua; Andrews, Sean M.; Wilner, David J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Corder, Stuartt A. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Dullemond, C. P. [Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Lin Shinyi [Department of Physics, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Hughes, A. M. [Department of Astronomy, University of California at Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States); D' Alessio, Paola [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 72-3 (Xangari), 58089 Morelia, Michoacan (Mexico); Ho, P. T. P. [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China)
2012-10-01
We present a detailed analysis of the spatially and spectrally resolved {sup 12}CO J = 2-1 and J = 3-2 emission lines from the TW Hya circumstellar disk, based on science verification data from the Atacama Large Millimeter/submillimeter Array (ALMA). These lines exhibit substantial emission in their high-velocity wings (with projected velocities out to 2.1 km s{sup -1}, corresponding to intrinsic orbital velocities >20 km s{sup -1}) that trace molecular gas as close as 2 AU from the central star. However, we are not able to reproduce the intensity of these wings and the general spatio-kinematic pattern of the lines with simple models for the disk structure and kinematics. Using three-dimensional non-local thermodynamic equilibrium molecular excitation and radiative transfer calculations, we construct some alternative models that successfully account for these features by modifying either (1) the temperature structure of the inner disk (inside the dust-depleted disk cavity; r < 4 AU), (2) the intrinsic (Keplerian) disk velocity field, or (3) the distribution of disk inclination angles (a warp). The latter approach is particularly compelling because a representative warped disk model qualitatively reproduces the observed azimuthal modulation of optical light scattered off the disk surface. In any model scenario, the ALMA data clearly require a substantial molecular gas reservoir located inside the region where dust optical depths are known to be substantially diminished in the TW Hya disk, in agreement with previous studies based on infrared spectroscopy. The results from these updated model prescriptions are discussed in terms of their potential physical origins, which might include dynamical perturbations from a low-mass companion with an orbital separation of a few AU.
5. A Comparison of Moment Rates for the Eastern Mediterranean Region from Competitive Kinematic Models
Science.gov (United States)
Klein, E. C.; Ozeren, M. S.; Shen-Tu, B.; Galgana, G. A.
2017-12-01
Relatively continuous, complex, and long-lived episodes of tectonic deformation gradually shaped the lithosphere of the eastern Mediterranean region into its present state. This large geodynamically interconnected and seismically active region absorbs, accumulates and transmits strains arising from stresses associated with: (1) steady northward convergence of the Arabian and African plates; (2) differences in lithospheric gravitational potential energy; and (3) basal tractions exerted by subduction along the Hellenic and Cyprus Arcs. Over the last twenty years, numerous kinematic models have been built using a variety of assumptions to take advantage of the extensive and dense GPS observations made across the entire region resulting in a far better characterization of the neotectonic deformation field than ever previously achieved. In this study, three separate horizontal strain rate field solutions obtained from three, region-wide, GPS only based kinematic models (i.e., a regional block model, a regional continuum model, and global continuum model) are utilized to estimate the distribution and uncertainty of geodetic moment rates within the eastern Mediterranean region. The geodetic moment rates from each model are also compared with seismic moment release rates gleaned from historic earthquake data. Moreover, kinematic styles of deformation derived from each of the modeled horizontal strain rate fields are examined for their degree of correlation with earthquake rupture styles defined by proximal centroid moment tensor solutions. This study suggests that significant differences in geodetically obtained moment rates from competitive kinematic models may introduce unforeseen bias into regularly updated, geodetically constrained, regional seismic hazard assessments.
6. Hidden Broad-line Regions in Seyfert 2 Galaxies: From the Spectropolarimetric Perspective
International Nuclear Information System (INIS)
Du, Pu; Wang, Jian-Min; Zhang, Zhi-Xiang
2017-01-01
The hidden broad-line regions (BLRs) in Seyfert 2 galaxies, which display broad emission lines (BELs) in their polarized spectra, are a key piece of evidence in support of the unified model for active galactic nuclei (AGNs). However, the detailed kinematics and geometry of hidden BLRs are still not fully understood. The virial factor obtained from reverberation mapping of type 1 AGNs may be a useful diagnostic of the nature of hidden BLRs in type 2 objects. In order to understand the hidden BLRs, we compile six type 2 objects from the literature with polarized BELs and dynamical measurements of black hole masses. All of them contain pseudobulges. We estimate their virial factors, and find the average value is 0.60 and the standard deviation is 0.69, which agree well with the value of type 1 AGNs with pseudobulges. This study demonstrates that (1) the geometry and kinematics of BLR are similar in type 1 and type 2 AGNs of the same bulge type (pseudobulges), and (2) the small values of virial factors in Seyfert 2 galaxies suggest that, similar to type 1 AGNs, BLRs tend to be very thick disks in type 2 objects.
7. Constraints on the outer radius of the broad emission line region of active galactic nuclei
Science.gov (United States)
Landt, Hermine; Ward, Martin J.; Elvis, Martin; Karovska, Margarita
2014-03-01
Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow components of their emission lines. We show that the narrow component of the higher-order Paschen lines is absent in all sources, revealing a broad emission line profile with a broad, flat top. This indicates that the BELR is kinematically separate from the narrow emission line region. We use the virial theorem to estimate the BELR outer radius from the flat top width of the unblended profiles of the strongest Paschen lines, Paα and Paβ, and find that it scales with the ionizing continuum luminosity roughly as expected from photoionization theory. The value of the incident continuum photon flux resulting from this relationship corresponds to that required for dust sublimation. A flat-topped broad emission line profile is produced by both a spherical gas distribution in orbital motion and an accretion disc wind if the ratio between the BELR outer and inner radius is assumed to be less than ˜100-200. On the other hand, a pure Keplerian disc can be largely excluded, since for most orientations and radial extents of the disc the emission line profile is double-horned.
8. Kinematic model of some types of motion of matter in active regions
International Nuclear Information System (INIS)
Platov, Yu.V.
1983-01-01
The kinematics of matter motion in variable magnetic fields of active regions on the Sun in the MHD approximation of a strong field and cold plasma is investigated. It is shown that the variation of sunspot magnetic moments lead to the development of different active phenomena in the solar atmosphere. The development of such phenomena at first can occur at the phase of active region growth, when new sunspots together with developed sunspots emerge in an active region or relative motions take place in a sunspot group
9. CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging
Energy Technology Data Exchange (ETDEWEB)
Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Wang, Junfeng [Department of Astronomy, Physics Building, Xiamen University Xiamen, Fujian, 361005 (China); Storchi-Bergmann, Thaisa, E-mail: walter.maksym@cfa.harvard.edu [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, IF, CP 15051, 91501-970 Porto Alegre, RS (Brazil)
2017-07-20
The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra 's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O iii], [S ii], and H α , as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc) across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ∼10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include H α evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.
10. CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging
Science.gov (United States)
Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John; Wang, Junfeng; Storchi-Bergmann, Thaisa
2017-07-01
The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O III], [S II], and Hα, as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc) across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ˜10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include Hα evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.
11. CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging
International Nuclear Information System (INIS)
Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John; Wang, Junfeng; Storchi-Bergmann, Thaisa
2017-01-01
The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra 's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O iii], [S ii], and H α , as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc) across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ∼10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include H α evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.
12. A catapult model for the narrow-line region in Seyferts and radio galaxies
International Nuclear Information System (INIS)
Smith, M.D.
1984-01-01
The kinematics and stability of clouds falling radially into a supersonic wind are studied. A critical parameter is found, the ejection coefficient, which separates clouds which continue to gravitate inwards from those which are catapulted out by the ram pressure of the wind. This leads to a maximum size for ejected clouds. The clouds are partially broken up by fluid dynamic instabilities and the fragments expelled with enhanced velocities. This model is applied to the narrow-line region of Seyferts and radio galaxies. A quasi-steady picture may be established for the wind-ambient medium interaction zone. The wind is shocked and escapes through jets or bubbles; the ambient medium cools, forming the clouds which gravitate inwards. (author)
13. Spatial and kinematic structure of Monoceros star-forming region
Science.gov (United States)
Costado, M. T.; Alfaro, E. J.
2018-05-01
The principal aim of this work is to study the velocity field in the Monoceros star-forming region using the radial velocity data available in the literature, as well as astrometric data from the Gaia first release. This region is a large star-forming complex formed by two associations named Monoceros OB1 and OB2. We have collected radial velocity data for more than 400 stars in the area of 8 × 12 deg2 and distance for more than 200 objects. We apply a clustering analysis in the subspace of the phase space formed by angular coordinates and radial velocity or distance data using the Spectrum of Kinematic Grouping methodology. We found four and three spatial groupings in radial velocity and distance variables, respectively, corresponding to the Local arm, the central clusters forming the associations and the Perseus arm, respectively.
14. Nonpartonic Effects in Pion Electroproduction in the Hermes Kinematical Region
International Nuclear Information System (INIS)
Uleshchenko, V.; Szczurek, A.
2002-01-01
The presentation is concerned with higher twist corrections of nonpartonic origin to semi-inclusive observables in the kinematical region relevant for the HERMES experiment. We demonstrate a strong impact of the VDM-like interaction and the exclusive production of ρ 0 meson on the extraction of the (anti)d - (anti)u asymmetry from charged pion DIS multiplicities. We also show that it is the exclusive- ρ 0 channel which accounts for the experimentally observed effect of the excess of charged over neutral pions produced at large z. (author)
15. The SLUGGS survey: wide-field stellar kinematics of early-type galaxies
Energy Technology Data Exchange (ETDEWEB)
Arnold, Jacob A. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Romanowsky, Aaron J.; Brodie, Jean P.; Woodley, Kristin A. [University of California Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States); Forbes, Duncan A.; Blom, Christina; Kartha, Sreeja S.; Pastorello, Nicola; Pota, Vincenzo; Usher, Christopher [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Spitler, Lee R. [Department of Physics and Astronomy, Faculty of Sciences, Macquarie University, Sydney, NSW 2109 (Australia); Foster, Caroline, E-mail: romanow@ucolick.org [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW (Australia)
2014-08-20
We present stellar kinematics of 22 nearby early-type galaxies (ETGs), based on two-dimensional (2D) absorption line stellar spectroscopy out to ∼2-4 R {sub e} (effective radii), as part of the ongoing SLUGGS Survey. The galaxies span a factor of 20 in intrinsic luminosity, as well as a full range of environment and ETG morphology. Our data consist of good velocity resolution (σ{sub inst} ∼ 25 km s{sup –1}) integrated stellar-light spectra extracted from the individual slitlets of custom made Keck/DEIMOS slitmasks. We extract stellar kinematics measurements (V, σ, h {sub 3}, and h {sub 4}) for each galaxy. Combining with literature values from smaller radii, we present 2D spatially resolved maps of the large-scale kinematic structure in each galaxy. We find that the kinematic homogeneity found inside 1 R {sub e} often breaks down at larger radii, where a variety of kinematic behaviors are observed. While central slow rotators remain slowly rotating in their halos, central fast rotators show more diversity, ranging from rapidly increasing to rapidly declining specific angular momentum profiles in the outer regions. There are indications that the outer trends depend on morphological type, raising questions about the proposed unification of the elliptical and lenticular (S0) galaxy families in the ATLAS{sup 3D} survey. Several galaxies in our sample show multiple lines of evidence for distinct disk components embedded in more slowly rotating spheroids, and we suggest a joint photometric-kinematic approach for robust bulge-disk decomposition. Our observational results appear generally consistent with a picture of two-phase (in-situ plus accretion) galaxy formation.
16. H I versus H α - comparing the kinematic tracers in modelling the initial conditions of the Mice
Science.gov (United States)
Mortazavi, S. Alireza; Lotz, Jennifer M.; Barnes, Joshua E.; Privon, George C.; Snyder, Gregory F.
2018-03-01
We explore the effect of using different kinematic tracers (H I and H α) on reconstructing the encounter parameters of the Mice major galaxy merger (NGC 4676A/B). We observed the Mice using the SparsePak Integral Field Unit (IFU) on the WIYN telescope, and compared the H α velocity map with VLA H I observations. The relatively high spectral resolution of our data (R ≈ 5000) allows us to resolve more than one kinematic component in the emission lines of some fibres. We separate the H α-[N II] emission of the star-forming regions from shocks using their [N II]/H α line ratio and velocity dispersion. We show that the velocity of star-forming regions agree with that of the cold gas (H I), particularly, in the tidal tails of the system. We reconstruct the morphology and kinematics of these tidal tails utilizing an automated modelling method based on the IDENTIKIT software package. We quantify the goodness of fit and the uncertainties of the derived encounter parameters. Most of the initial conditions reconstructed using H α and H I are consistent with each other, and qualitatively agree with the results of previous works. For example, we find 210± ^{50}_{40} Myr, and 180± ^{50}_{40} Myr for the time since pericentre, when modelling H α and H I kinematics, respectively. This confirms that in some cases, H α kinematics can be used instead of H I kinematics for reconstructing the initial conditions of galaxy mergers, and our automated modelling method is applicable to some merging systems.
17. Kinematic space and wormholes
Energy Technology Data Exchange (ETDEWEB)
Zhang, Jian-dong [TianQin Research Center for Gravitational Physics, Sun Yat-sen University, Zhuhai 519082, Guangdong (China); Chen, Bin [Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, 5 Yiheyuan Rd, Beijing 100871 (China); Center for High Energy Physics, Peking University, 5 Yiheyuan Rd, Beijing 100871 (China)
2017-01-23
The kinematic space could play a key role in constructing the bulk geometry from dual CFT. In this paper, we study the kinematic space from geometric points of view, without resorting to differential entropy. We find that the kinematic space could be intrinsically defined in the embedding space. For each oriented geodesic in the Poincaré disk, there is a corresponding point in the kinematic space. This point is the tip of the causal diamond of the disk whose intersection with the Poincaré disk determines the geodesic. In this geometric construction, the causal structure in the kinematic space can be seen clearly. Moreover, we find that every transformation in the SL(2,ℝ) leads to a geodesic in the kinematic space. In particular, for a hyperbolic transformation defining a BTZ black hole, it is a timelike geodesic in the kinematic space. We show that the horizon length of the static BTZ black hole could be computed by the geodesic length of corresponding points in the kinematic space. Furthermore, we discuss the fundamental regions in the kinematic space for the BTZ blackhole and multi-boundary wormholes.
18. The case for inflow of the broad-line region of active galactic nuclei
Science.gov (United States)
Gaskell, C. Martin; Goosmann, René W.
2016-02-01
The high-ionization lines of the broad-line region (BLR) of thermal active galactic nuclei (AGNs) show blueshifts of a few hundred km/s to several thousand km/sec with respect to the low-ionization lines. This has long been thought to be due to the high-ionization lines of the BLR arising in a wind of which the far side of the outflow is blocked from our view by the accretion disc. Evidence for and against the disc-wind model is discussed. The biggest problem for the model is that velocity-resolved reverberation mapping repeatedly fails to show the expected kinematic signature of outflow of the BLR. The disc-wind model also cannot readily reproduce the red side of the line profiles of high-ionization lines. The rapidly falling density in an outflow makes it difficult to obtain high equivalent widths. We point out a number of major problems with associating the BLR with the outflows producing broad absorption lines. An explanation which avoids all these problems and satisfies the constraints of both the line profiles and velocity-resolved reverberation-mapping is a model in which the blueshifting is due to scattering off material spiraling inwards with an inflow velocity of half the velocity of the blueshifting. We discuss how recent reverberation mapping results are consistent with the scattering-plus-inflow model but do not support a disc-wind model. We propose that the anti-correlation of the apparent redshifting of Hβ with the blueshifting of C iv is a consequence of contamination of the red wings of Hβ by the broad wings of [O iii].
19. MICROLENSING OF QUASAR BROAD EMISSION LINES: CONSTRAINTS ON BROAD LINE REGION SIZE
Energy Technology Data Exchange (ETDEWEB)
Guerras, E.; Mediavilla, E. [Instituto de Astrofisica de Canarias, Via Lactea S/N, La Laguna E-38200, Tenerife (Spain); Jimenez-Vicente, J. [Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Campus de Fuentenueva, E-18071 Granada (Spain); Kochanek, C. S. [Department of Astronomy and the Center for Cosmology and Astroparticle Physics, The Ohio State University, 4055 McPherson Lab, 140 West 18th Avenue, Columbus, OH 43221 (United States); Munoz, J. A. [Departamento de Astronomia y Astrofisica, Universidad de Valencia, E-46100 Burjassot, Valencia (Spain); Falco, E. [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Motta, V. [Departamento de Fisica y Astronomia, Universidad de Valparaiso, Avda. Gran Bretana 1111, Valparaiso (Chile)
2013-02-20
We measure the differential microlensing of the broad emission lines between 18 quasar image pairs in 16 gravitational lenses. We find that the broad emission lines are in general weakly microlensed. The results show, at a modest level of confidence (1.8{sigma}), that high ionization lines such as C IV are more strongly microlensed than low ionization lines such as H{beta}, indicating that the high ionization line emission regions are more compact. If we statistically model the distribution of microlensing magnifications, we obtain estimates for the broad line region size of r{sub s} = 24{sup +22} {sub -15} and r{sub s} = 55{sup +150} {sub -35} lt-day (90% confidence) for the high and low ionization lines, respectively. When the samples are divided into higher and lower luminosity quasars, we find that the line emission regions of more luminous quasars are larger, with a slope consistent with the expected scaling from photoionization models. Our estimates also agree well with the results from local reveberation mapping studies.
20. Studies of kinematic elements in two multicenter sunspot groups
International Nuclear Information System (INIS)
Korobova, Z.B.
1983-01-01
Some features of kinematic elements (KE) in two multicenter sunspot groups were studied using Tashkent full-disc white light heliograms. KE and morphological elements do not reveal any relationship. A KE coincides with a unipolar or multipolar spot or with part of a spot. It may also contain an extended stream including several spots. Relation of KE to large-scale photospheric magnetic fields is less clear. The line of polarity reversal is, in most cases, the deviding line between two adjacent KE. At the same time, a KE can contain spots of both polarities. Sunspot trajectories in the leading polarity regions show the best similarity. Interactions of KE are greatly influenced by the meridional drift. (author)
1. Kinematic Study of Ionized and Molecular Gases in Ultracompact HII Region in Monoceros R2
Science.gov (United States)
Kim, Hwihyun; Lacy, John H.; Jaffe, Daniel Thomas
2017-06-01
Monoceros R2 (Mon R2) is an UltraCompact HII region (UCHII) surrounded by several PhotoDissociation Regions (PDRs). It is an excellent example to investigate the chemistry and physics of early stage of massive star formation due to its proximity (830pc) and brightness. Previous studies suggest that the wind from the star holds the ionized gas up against the dense molecular core and the higher pressure at the head drives the ionized gas along the shell. In order for the model to work, there should be evidence for dense molecular gas along the shell walls, irradiated by the UCHII region and perhaps entrained into the flow along the walls.We obtained the Immersion Grating INfrared Spectrograph (IGRINS) spectra of Mon R2 to study the kinematic patterns in the areas where ionized and molecular gases interact. The position-velocity maps from the high resolution (R~45,000) H- and K-band (1.4-2.5μm) IGRINS spectra demonstrate that the ionized gases (Brackett and Pfund series, He and Fe emission lines; Δv ≈ 40km/s) flow along the walls of the surrounding clouds. This is consistent with the model by Zhu et al. (2008). In the PV maps of the H2 emission lines there is no obvious motion (Δv ≈ 10km/s) of the molecular hydrogen right at the ionization boundary. This implies that the molecular gas is not taking part in the flow as the ionized gas is moving along the cavity walls.This work used the Immersion Grating Infrared Spectrograph (IGRINS) that was developed under a collaboration between the University of Texas at Austin and the Korea Astronomy and Space Science Institute (KASI) with the financial support of the US National Science Foundation (NSF; grant AST-1229522), of the University of Texas at Austin, and of the Korean GMTProject of KASI.
2. Fault-Tolerant Region-Based Control of an Underwater Vehicle with Kinematically Redundant Thrusters
Directory of Open Access Journals (Sweden)
Zool H. Ismail
2014-01-01
Full Text Available This paper presents a new control approach for an underwater vehicle with a kinematically redundant thruster system. This control scheme is derived based on a fault-tolerant decomposition for thruster force allocation and a region control scheme for the tracking objective. Given a redundant thruster system, that is, six or more pairs of thrusters are used, the proposed redundancy resolution and region control scheme determine the number of thruster faults, as well as providing the reference thruster forces in order to keep the underwater vehicle within the desired region. The stability of the presented control law is proven in the sense of a Lyapunov function. Numerical simulations are performed with an omnidirectional underwater vehicle and the results of the proposed scheme illustrate the effectiveness in terms of optimizing the thruster forces.
3. THE PHOTOMETRIC AND KINEMATIC STRUCTURE OF FACE-ON DISK GALAXIES. II. INTEGRATED LINE PROFILE CHARACTERIZATION AND THE ORIGIN OF LINE PROFILE ASYMMETRY
International Nuclear Information System (INIS)
Andersen, David R.; Bershady, Matthew A.
2009-01-01
We perform a moments analysis of H I and H II global line profiles for 33 nearly face-on disk galaxies for the threefold purpose of rationalizing and interpreting line profile indices in the literature, presenting robust moment definitions with analytic error functions calibrated against Monte Carlo simulation, and probing the physical origin of line profile asymmetries. The first four profile moments serve as viable surrogates for the recession velocity, line width, asymmetry, and profile shape, respectively. The first three moments are superior, by a factor of ∼2 in precision, to related quantities defined in the literature. First and third profile moments are related; skew can be used to calculate more accurate recession velocities from global profiles. Second and fourth profile moments are linked, corresponding to the known trend that narrow (but well resolved) line widths tend to be more Gaussian. Hα kurtosis also appears correlated with the spatially resolved line width of the ionized gas. No systematics appear between various measures of line width and true rotation speed other than the wide range of normalizations, which we calibrate. This conclusion and calibration, however, is highly sample dependent. The ratio of H II to H I widths is consistent with unity, even at low projected line width. There may be a trend toward a decrease in the ratio of H II to H I widths consistent with previous studies, but we also observe greater scatter. While there is good agreement between H I and H II first, second, and fourth moments, we find no positive correlation between skew measured from H I and H II profiles. Detailed analysis of the spatially resolved Hα distribution demonstrates that H II global profile asymmetries are dominated by differences in the gas distribution, not kinematic asymmetries.
4. Anisotropic ionizing radiation in Seyfert galaxies. I - The extended narrow-line region in Markarian 573
Science.gov (United States)
Tsvetanov, Zlatan; Walsh, J. R.
1992-01-01
The morphology, kinematics, and ionization state of the nuclear extended narrow-line region (ENLR) of the Seyfert 2 galaxy Mrk 573 are studied using narrow-band images of a grid of long-slit spectra. The entire ENLR is mapped spectroscopically, and velocity structure is studied. The velocity field map shows a typical galactic rotation picture with some important deviations. A simple geometric model, in accordance with the 'unified schemes', is employed to study the effects of various parameters of the observed picture. The best match is achieved when a biconical radiation field illuminates the ISM of the host galaxy that takes part in a normal galaxy rotation but also has radial motions close to the nucleus. The emission-line images reveal an ENLR elongated along the radio axis in the northwest-southeast direction, but a map of the flux ratio forbidden O III 5007/(H-alpha + forbidden N II) shows a different structure, with the highest excitation peak offset by about 4 arcsec along the radio axis to the southeast.
5. Inverse Kinematics
Directory of Open Access Journals (Sweden)
Joel Sereno
2010-01-01
Full Text Available Inverse kinematics is the process of converting a Cartesian point in space into a set of joint angles to more efficiently move the end effector of a robot to a desired orientation. This project investigates the inverse kinematics of a robotic hand with fingers under various scenarios. Assuming the parameters of a provided robot, a general equation for the end effector point was calculated and used to plot the region of space that it can reach. Further, the benefits obtained from the addition of a prismatic joint versus an extra variable angle joint were considered. The results confirmed that having more movable parts, such as prismatic points and changing angles, increases the effective reach of a robotic hand.
6. GASP. II. A MUSE View of Extreme Ram-Pressure Stripping along the Line of Sight: Kinematics of the Jellyfish Galaxy JO201
Science.gov (United States)
Bellhouse, C.; Jaffé, Y. L.; Hau, G. K. T.; McGee, S. L.; Poggianti, B. M.; Moretti, A.; Gullieuszik, M.; Bettoni, D.; Fasano, G.; D'Onofrio, M.; Fritz, J.; Omizzolo, A.; Sheen, Y.-K.; Vulcani, B.
2017-07-01
This paper presents a spatially resolved kinematic study of the jellyfish galaxy JO201, one of the most spectacular cases of ram-pressure stripping (RPS) in the GAs Stripping Phenomena in galaxies with MUSE (GASP) survey. By studying the environment of JO201, we find that it is moving through the dense intracluster medium of Abell 85 at supersonic speeds along our line of sight, and that it is likely accompanied by a small group of galaxies. Given the density of the intracluster medium and the galaxy’s mass, projected position, and velocity within the cluster, we estimate that JO201 must so far have lost ˜50% of its gas during infall via RPS. The MUSE data indeed reveal a smooth stellar disk accompanied by large projected tails of ionized ({{H}}α ) gas, composed of kinematically cold (velocity dispersion 100 km s-1) diffuse emission, that extend out to at least ˜ 50 {kpc} from the galaxy center. The ionized {{H}}α -emitting gas in the disk rotates with the stars out to ˜6 kpc but, in the disk outskirts, it becomes increasingly redshifted with respect to the (undisturbed) stellar disk. The observed disturbances are consistent with the presence of gas trailing behind the stellar component resulting from intense face-on RPS along the line of sight. Our kinematic analysis is consistent with the estimated fraction of lost gas and reveals that stripping of the disk happens outside-in, causing shock heating and gas compression in the stripped tails.
7. Inverse kinematic-based robot control
Science.gov (United States)
Wolovich, W. A.; Flueckiger, K. F.
1987-01-01
A fundamental problem which must be resolved in virtually all non-trivial robotic operations is the well-known inverse kinematic question. More specifically, most of the tasks which robots are called upon to perform are specified in Cartesian (x,y,z) space, such as simple tracking along one or more straight line paths or following a specified surfacer with compliant force sensors and/or visual feedback. In all cases, control is actually implemented through coordinated motion of the various links which comprise the manipulator; i.e., in link space. As a consequence, the control computer of every sophisticated anthropomorphic robot must contain provisions for solving the inverse kinematic problem which, in the case of simple, non-redundant position control, involves the determination of the first three link angles, theta sub 1, theta sub 2, and theta sub 3, which produce a desired wrist origin position P sub xw, P sub yw, and P sub zw at the end of link 3 relative to some fixed base frame. Researchers outline a new inverse kinematic solution and demonstrate its potential via some recent computer simulations. They also compare it to current inverse kinematic methods and outline some of the remaining problems which will be addressed in order to render it fully operational. Also discussed are a number of practical consequences of this technique beyond its obvious use in solving the inverse kinematic question.
8. Spectral properties of the narrow-line region in Seyfert galaxies selected from the SDSS-DR7
Science.gov (United States)
Vaona, L.; Ciroi, S.; Di Mille, F.; Cracco, V.; La Mura, G.; Rafanelli, P.
2012-12-01
Although the properties of the narrow-line region (NLR) of active galactic nuclei (AGN) have been deeply studied by many authors in the past three decades, many questions are still open. The main goal of this work is to explore the NLR of Seyfert galaxies by collecting a large statistical spectroscopic sample of Seyfert 2 and Intermediate-type Seyfert galaxies having a high signal-to-noise ratio in order to take advantage of a high number of emission lines to be accurately measured. 2153 Seyfert 2 and 521 Intermediate-type Seyfert spectra were selected from Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) with a diagnostic diagram based on the oxygen emission-line ratios. All the emission lines, broad components included, were measured by means of a self-developed code, after the subtraction of the stellar component. Physical parameters, such as internal reddening, ionization parameter, temperature, density, gas and stellar velocity dispersion were determined for each object. Furthermore, we estimated mass and radius of the NLR, kinetic energy of the ionized gas and black hole accretion rate. From the emission-line analysis and the estimated physical properties, it appears that the NLR is similar in Seyfert 2 and Intermediate-Seyfert galaxies. The only differences, lower extinction, gas kinematics in general not dominated by the host galaxy gravitational potential and higher percentage of [O III]λ5007 blue asymmetries in Intermediate-Seyfert, can be ascribed to an effect of inclination of our line of sight with respect to the torus axis.
9. Unveiling the inner morphology and gas kinematics of NGC 5135 with ALMA
Science.gov (United States)
Sabatini, G.; Gruppioni, C.; Massardi, M.; Giannetti, A.; Burkutean, S.; Cimatti, A.; Pozzi, F.; Talia, M.
2018-06-01
The local Seyfert 2 galaxy NGC 5135, thanks to its almost face-on appearance, a bulge overdensity of stars, the presence of a large-scale bar, an active galactic nucleus (AGN) and a supernova remnant, is an excellent target to investigate the dynamics of inflows, outflows, star formation, and AGN feedback. Here, we present a reconstruction of the gas morphology and kinematics in the inner regions of this galaxy, based on the analysis of Atacama Large Millimeter Array (ALMA) archival data. For this purpose, we combine the available ˜100 pc resolution ALMA 1.3 and 0.45 mm observations of dust continuum emission, the spectroscopic maps of two transitions of the CO molecule (tracer of molecular gas mass in star-forming and nuclear regions), and of the CS molecule (tracer of the dense star-forming regions) with the outcome of the spectral energy distribution decomposition. By applying the 3DBAROLO software (3D-Based Analysis of Rotating Objects from Line Observations), we have been able to fit the galaxy rotation curve using a 3D tilted-ring model of the disc. Most of the observed emitting features are described by our kinematic model. We also attempt an interpretation for the emission in a few regions that the axisymmetric model fails to reproduce. The most relevant of these is a region at the northern edge of the inner bar, where multiple velocity components overlap, as a possible consequence of the expansion of a superbubble.
10. Parallel kinematics type, kinematics, and optimal design
CERN Document Server
Liu, Xin-Jun
2014-01-01
Parallel Kinematics- Type, Kinematics, and Optimal Design presents the results of 15 year's research on parallel mechanisms and parallel kinematics machines. This book covers the systematic classification of parallel mechanisms (PMs) as well as providing a large number of mechanical architectures of PMs available for use in practical applications. It focuses on the kinematic design of parallel robots. One successful application of parallel mechanisms in the field of machine tools, which is also called parallel kinematics machines, has been the emerging trend in advanced machine tools. The book describes not only the main aspects and important topics in parallel kinematics, but also references novel concepts and approaches, i.e. type synthesis based on evolution, performance evaluation and optimization based on screw theory, singularity model taking into account motion and force transmissibility, and others. This book is intended for researchers, scientists, engineers and postgraduates or above with interes...
11. Water line positions in the 782–840 nm region
International Nuclear Information System (INIS)
Hu, S.-M.; Chen, B.; Tan, Y.; Wang, J.; Cheng, C.-F.; Liu, A.-W.
2015-01-01
A set of water transitions in the 782–840 nm region, including 38 H 2 16 O lines, 12 HD 16 O lines, and 30 D 2 16 O lines, were recorded with a cavity ring-down spectrometer calibrated using precise atomic lines. Absolute frequencies of the lines were determined with an accuracy of about 5 MHz. Systematic shifts were found in the line positions given in the HITRAN database and the upper energy levels given in recent MARVEL studies. - Highlights: • Cavity ring-down spectra of H 2 16 O, HD 16 O, and D 2 16 O lines in the 782–840 nm region were measured. • Absolute line positions of 80 water lines were determined with an accuracy of about 5 MHz. • The H 2 16 O positions given in HITRAN have a systematic shift of 0.001 cm −1 in the 796–840 nm region. • MARVEL D 2 16 O energies have a systematic deviation of about −0.008 cm −1
12. Kinematics of the inner thousand AU region around the young massive star AFGL 2591-VLA3: a massive disk candidate?
NARCIS (Netherlands)
Wang, K. -S.; van der Tak, F. F. S.; Hogerheijde, M. R.
Context. Recent detections of disks around young high-mass stars support the idea of massive star formation through accretion rather than coalescence, but the detailed kinematics in the equatorial region of the disk candidates is not well known, which limits our understanding of the accretion
13. A DOUBLE-RING ALGORITHM FOR MODELING SOLAR ACTIVE REGIONS: UNIFYING KINEMATIC DYNAMO MODELS AND SURFACE FLUX-TRANSPORT SIMULATIONS
International Nuclear Information System (INIS)
Munoz-Jaramillo, Andres; Martens, Petrus C. H.; Nandy, Dibyendu; Yeates, Anthony R.
2010-01-01
The emergence of tilted bipolar active regions (ARs) and the dispersal of their flux, mediated via processes such as diffusion, differential rotation, and meridional circulation, is believed to be responsible for the reversal of the Sun's polar field. This process (commonly known as the Babcock-Leighton mechanism) is usually modeled as a near-surface, spatially distributed α-effect in kinematic mean-field dynamo models. However, this formulation leads to a relationship between polar field strength and meridional flow speed which is opposite to that suggested by physical insight and predicted by surface flux-transport simulations. With this in mind, we present an improved double-ring algorithm for modeling the Babcock-Leighton mechanism based on AR eruption, within the framework of an axisymmetric dynamo model. Using surface flux-transport simulations, we first show that an axisymmetric formulation-which is usually invoked in kinematic dynamo models-can reasonably approximate the surface flux dynamics. Finally, we demonstrate that our treatment of the Babcock-Leighton mechanism through double-ring eruption leads to an inverse relationship between polar field strength and meridional flow speed as expected, reconciling the discrepancy between surface flux-transport simulations and kinematic dynamo models.
14. Suspension kinematic analysis of UTeM’s FV Malaysia electric vehicle racing car
NARCIS (Netherlands)
Abdul Manaf, M.Z.; Latif, M.F.A.; Razak, M.S.A.; Hassan, M.Z.B.; Rosley, M.I.F.
2016-01-01
The purpose of this paper is to investigate the kinematic performance of students’ racing car, namely UTeM’s FV Malaysia Electric Vehicle. An elasto-kinematic analysis approach is used to predict the car’s performance during straight line drive and curvature drive. Two suspension design factors
15. The End of the Lines for OX 169: No Binary Broad-Line Region
Science.gov (United States)
Halpern, J. P.; Eracleous, M.
2000-03-01
We show that unusual Balmer emission-line profiles of the quasar OX 169, frequently described as either self-absorbed or double peaked, are actually neither. The effect is an illusion resulting from two coincidences. First, the forbidden lines are quite strong and broad. Consequently, the [N II] λ6583 line and the associated narrow-line component of Hα present the appearance of twin Hα peaks. Second, the redshift of 0.2110 brings Hβ into coincidence with Na I D at zero redshift, and ISM absorption in Na I D divides the Hβ emission line. In spectra obtained over the past decade, we see no substantial change in the character of the line profiles and no indication of intrinsic double-peaked structure. The Hγ, Mg II, and Lyα emission lines are single peaked, and all of the emission-line redshifts are consistent once they are correctly attributed to their permitted and forbidden-line identifications. A systematic shift of up to 700 km s-1 between broad and narrow lines is seen, but such differences are common and could be due to gravitational and transverse redshift in a low-inclination disk. Stockton & Farnham had called attention to an apparent tidal tail in the host galaxy of OX 169 and speculated that a recent merger had supplied the nucleus with a coalescing pair of black holes that was now revealing its existence in the form of two physically distinct broad-line regions. Although there is no longer any evidence for two broad emission-line regions in OX 169, binary black holes should form frequently in galaxy mergers, and it is still worthwhile to monitor the radial velocities of emission lines that could supply evidence of their existence in certain objects.
16. THE DISCREPANT KINEMATICS OF ORLs AND CELs IN NGC 7009 AS A FUNCTION OF IONIZATION STRUCTURE
Energy Technology Data Exchange (ETDEWEB)
Richer, Michael G. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apartado Postal 106, 22800 Ensenada, BC (Mexico); Georgiev, Leonid; Torres-Peimbert, Silvia [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-264, CP 04510 Mexico DF (Mexico); Arrieta, Anabel, E-mail: richer@astrosen.unam.mx, E-mail: silvia@astroscu.unam.mx, E-mail: anabel.arrieta@ibero.mx [Departamento de Fisica y Matematicas, Universidad Iberoamericana, Prolongacion Paseo de la Reforma 880, Lomas de Santa Fe, CP 01210 Mexico DF (Mexico)
2013-08-20
We present spatially and velocity-resolved echelle spectroscopy for NGC 7009 obtained with the UVES spectrograph at the European Southern Observatory's Very Large Telescope. Our objective is to analyze the kinematics of emission lines excited by recombination and collisions with electrons to determine whether similarities or differences could be useful in elucidating the well-known abundance discrepancy derived from them. We construct position-velocity maps for recombination, fluorescence, charge transfer, and collisionally excited lines. We find a plasma component emitting in the C II, N II, O II, and Ne II recombination lines whose kinematics are discrepant: they are incompatible with the ionization structure derived from all other evidence and the kinematics derived from all of these lines are unexpectedly very similar. We find direct evidence for a recombination contribution to [N II] {lambda}5755. Once taken into account, the electron temperatures from [N II], [O III], and [Ne III] agree at a given position and velocity. The electron densities derived from [O II] and [Ar IV] are consistent with direct imaging and the distribution of hydrogen emission. The kinematics of the C II, N II, O II, and Ne II lines does not coincide with the kinematics of the [O III] and [Ne III] forbidden emission, indicating that there is an additional plasma component to the recombination emission that arises from a different volume from that giving rise to the forbidden emission from the parent ions within NGC 7009. Thus, the chemical abundances derived from either type of line are correct only for the plasma component from which they arise. Apart from [N II] {lambda}5755, we find no anomaly with the forbidden lines usually used to determine chemical abundances in ionized nebulae, so the abundances derived from them should be reliable for the medium from which they arise.
17. On the Intermediate Line Region in AGNs
Energy Technology Data Exchange (ETDEWEB)
Adhikari, Tek P.; Różańska, Agata; Hryniewicz, Krzysztof [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Czerny, Bozena [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Ferland, Gary J., E-mail: tek@camk.edu.pl [Department of Physics and Astronomy, The University of Kentucky, Lexington, KY (United States)
2017-09-29
In this paper we explore the intermediate line region (ILR) by using the photoionisation simulations of the gas clouds present at different radial distances from the center, corresponding to the locations from BLR out to NLR in four types of AGNs. We let for the presence of dust whenever conditions allow for dust existence. All spectral shapes are taken from the recent multi-wavelength campaigns. The cloud density decreases with distance as a power law. We found that the slope of the power law density profile does not affect the line emissivity radial profiles of major emission lines: Hβ, He II, Mg II, C III, and O III. When the density of the cloud at the sublimation radius is as high as 10{sup 11.5} cm{sup −3}, the ILR should clearly be seen in the observations independently of the shape of the illuminating radiation. Moreover, our result is valid for low ionization nuclear emission regions of active galaxies.
18. Probing the physics of Seyfert galaxies using their emission-line regions
Energy Technology Data Exchange (ETDEWEB)
Shastri, P., E-mail: prajval.shastri@gmail.com; Kharb, P.; Jose, J.; Ramya, S.; Bhatt, H. C.; Gupta, M. [Indian Institute of Astrophysics, Bangalore (India); Dopita, M.; Kewley, L.; Davies, R.; Sutherland, R.; Hampton, E. [RSAA, Australian National University, Canberra (Australia); Scharwächter, J. [LERMA, Paris Observatory (France); Banfield, J. [CSIRO Astronomy and Space Science, Epping (Australia); Srivastava, S. [Department of Physics, DDU Gorakhpur University, Gorakhpur (India); Jin, J. [Department of Physics, University of Durham (United Kingdom); Basurah, H. [Astronomy Department, King Abdulaziz University, Jeddah (Saudi Arabia); Fischer, S. [German Aerospace Center, Bonn (Germany); Panda, S. [National Institute of Technology, Rourkela (India); Indian Institute of Astrophysics, Bangalore (India); Sundar, M. N. [Jain University, Bangalore (India); Radhakrishnan, V. [Broadcom Corporation, Bangalore (India)
2015-12-31
Active galaxies have powerhouses of radiation in their nuclear regions that are driven by accreting super-massive black holes. The accretion system also generates outflows of ionized gas and synchrotron-emitting bipolar jets of plasma, which could have a significant impact on the host galaxy. We have initiated an investigation into the physics of nearby active galaxies by studying the morphology, kinematics, excitation abundance structure, and radio structure of about 120 nearby targets. We present a few early results from this investigation.
19. SPATIAL ANISOTROPY OF GALAXY KINEMATICS IN SLOAN DIGITAL SKY SURVEY GALAXY CLUSTERS
International Nuclear Information System (INIS)
Skielboe, Andreas; Wojtak, Radosław; Pedersen, Kristian; Rozo, Eduardo; Rykoff, Eli S.
2012-01-01
Measurements of galaxy cluster kinematics are important in understanding the dynamical state and evolution of clusters of galaxies, as well as constraining cosmological models. While it is well established that clusters exhibit non-spherical geometries, evident in the distribution of galaxies on the sky, azimuthal variations of galaxy kinematics within clusters have yet to be observed. Here we measure the azimuthal dependence of the line-of-sight velocity dispersion profile in a stacked sample of 1743 galaxy clusters from the Sloan Digital Sky Survey (SDSS). The clusters are drawn from the SDSS DR8 redMaPPer catalog. We find that the line-of-sight velocity dispersion of galaxies lying along the major axis of the central galaxy is larger than those that lie along the minor axis. This is the first observational detection of anisotropic kinematics of galaxies in clusters. We show that the result is consistent with predictions from numerical simulations. Furthermore, we find that the degree of projected anisotropy is strongly dependent on the line-of-sight orientation of the galaxy cluster, opening new possibilities for assessing systematics in optical cluster finding.
20. Kinematics of the symbiotic system R Aqr
Science.gov (United States)
Navarro, S.; Corral, L. J.; Steffen, W.
2014-04-01
We present the results of the kinematical analysis of the symbiotic system R Aqr. We obtained high dispersion spectra with the MES spectrograph at the 2.1 m telescope of San Pedro Mártir (MEZCAL). The used filter were Ha + [NII], (λc = 6575Å, Δλ = 90Å). We analyse the [NII] λλ6583 line. When the observations are compared with previous ones by Solf (1992) we detected an important change in the projected velocities of the observed knots, supporting the idea of a precessing jet. We are working also in a 3-D kinematic model for the object using the measured velocities and the state of the model is presented.
1. Observability of planet-disc interactions in CO kinematics
Science.gov (United States)
Pérez, Sebastián; Casassus, S.; Benítez-Llambay, P.
2018-06-01
Empirical evidence of planets in gas-rich circumstellar discs is required to constrain giant planet formation theories. Here we study the kinematic patterns which arise from planet-disc interactions and their observability in CO rotational emission lines. We perform three-dimensional hydrodynamical simulations of single giant planets, and predict the emergent intensity field with radiative transfer. Pressure gradients at planet-carved gaps, spiral wakes and vortices bear strong kinematic counterparts. The iso-velocity contours in the CO(2-1) line centroids vo reveal large-scale perturbations, corresponding to abrupt transitions from below sub-Keplerian to super-Keplerian rotation along with radial and vertical flows. The increase in line optical depth at the edge of the gap also modulates vo, but this is a mild effect compared to the dynamical imprint of the planet-disc interaction. The large-scale deviations from the Keplerian rotation thus allow the planets to be indirectly detected via the first moment maps of molecular gas tracers, at ALMA angular resolutions. The strength of these deviations depends on the mass of the perturber. This initial study paves the way to eventually determine the mass of the planet by comparison with more detailed models.
2. Evidence for non-axisymmetry in M 31 from wide-field kinematics of stars and gas
Science.gov (United States)
Opitsch, M.; Fabricius, M. H.; Saglia, R. P.; Bender, R.; Blaña, M.; Gerhard, O.
2018-03-01
Aim. As the nearest large spiral galaxy, M 31 provides a unique opportunity to study the structure and evolutionary history of this galaxy type in great detail. Among the many observing programs aimed at M 31 are microlensing studies, which require good three-dimensional models of the stellar mass distribution. Possible non-axisymmetric structures like a bar need to be taken into account. Due to M 31's high inclination, the bar is difficult to detect in photometry alone. Therefore, detailed kinematic measurements are needed to constrain the possible existence and position of a bar in M 31. Methods: We obtained ≈220 separate fields with the optical integral-field unit spectrograph VIRUS-W, covering the whole bulge region of M 31 and parts of the disk. We derived stellar line-of-sight velocity distributions from the stellar absorption lines, as well as velocity distributions and line fluxes of the emission lines Hβ, [O III] and [N I]. Our data supersede any previous study in terms of spatial coverage and spectral resolution. Results: We find several features that are indicative of a bar in the kinematics of the stars, we see intermediate plateaus in the velocity and the velocity dispersion, and correlation between the higher moment h3 and the velocity. The gas kinematics is highly irregular, but is consistent with non-triaxial streaming motions caused by a bar. The morphology of the gas shows a spiral pattern, with seemingly lower inclination than the stellar disk. We also look at the ionization mechanisms of the gas, which happens mostly through shocks and not through starbursts. This paper includes data taken at The McDonald Observatory of The University of Texas at Austin.This research was supported by the DFG cluster of excellence "Origin and Structure of the Universe".Full Tables B.4-B.7 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A38
3. SPATIALLY RESOLVED GAS KINEMATICS WITHIN A Lyα NEBULA: EVIDENCE FOR LARGE-SCALE ROTATION
Energy Technology Data Exchange (ETDEWEB)
Prescott, Moire K. M. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Martin, Crystal L. [Department of Physics, Broida Hall, Mail Code 9530, University of California, Santa Barbara, CA 93106 (United States); Dey, Arjun, E-mail: mkmprescott@dark-cosmology.dk [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
2015-01-20
We use spatially extended measurements of Lyα as well as less optically thick emission lines from an ≈80 kpc Lyα nebula at z ≈ 1.67 to assess the role of resonant scattering and to disentangle kinematic signatures from Lyα radiative transfer effects. We find that the Lyα, C IV, He II, and C III] emission lines all tell a similar story in this system, and that the kinematics are broadly consistent with large-scale rotation. First, the observed surface brightness profiles are similar in extent in all four lines, strongly favoring a picture in which the Lyα photons are produced in situ instead of being resonantly scattered from a central source. Second, we see low kinematic offsets between Lyα and the less optically thick He II line (∼100-200 km s{sup –1}), providing further support for the argument that the Lyα and other emission lines are all being produced within the spatially extended gas. Finally, the full velocity field of the system shows coherent velocity shear in all emission lines: ≈500 km s{sup –1} over the central ≈50 kpc of the nebula. The kinematic profiles are broadly consistent with large-scale rotation in a gas disk that is at least partially stable against collapse. These observations suggest that the Lyα nebula represents accreting material that is illuminated by an offset, hidden active galactic nucleus or distributed star formation, and that is undergoing rotation in a clumpy and turbulent gas disk. With an implied mass of M(
4. Line-shape asymmetry of water vapor absorption lines in the 720-nm wavelength region
Science.gov (United States)
Grossmann, Benoist E.; Browell, Edward V.
1991-01-01
Spectral line-shape analyses were performed for water vapor lines broadened by argon, oxygen, and xenon in the 720-nm wavelength region. A line-shape asymmetry was observed, which is attributed to statistical dependence or correlation between velocity- and state-changing collisions. The generalized (asymmetric) Galatry profile, which results from the soft-collision profile and includes correlation between velocity- and state-changing collisions, was fitted to the observed line shapes and was found to compare favorably with the observed data. The most prominent asymmetries were observed with xenon as the buffer gas.
5. Wide-field kinematic structure of early-type galaxy halos
Science.gov (United States)
Arnold, Jacob Antony
2013-12-01
The stellar halos of nearby galaxies bare the signatures of the mass-assembly processes that have driven galaxy evolution over the last ˜10 Gyr. Finding and interpreting these relict clues in galaxies within and beyond the local group offers one of the most promising avenues for understanding how galaxies accumulate their stars over time. To tackle this problem we have performed a systematic study of the wide-field kinematic structure of nearby (Dspectroscopy out to several effective radii (˜3 R e). The 22 galaxies presented here span a range of environments (field, group, and cluster), intrinsic luminosities (-22.4 infrared Calcium II triplet. For each spectrum, we parameterize the line-of-sight velocity distribution (LOSVD) as a truncated Gauss-Hermite series convolved with an optimally weighted combination of stellar templates. These kinematic measurements (V, sigma, h3, and h4) are combined with literature values to construct spatially resolved maps of large-scale kinematic structure. A variety of kinematic behaviors are observed beyond ~1 Re, potentially reflecting the stochastic and chaotic assembly of stellar bulges and halos in early-type galaxies. Next, we describe a global analysis (out to 5 Re) of kinematics and metallicity in the nearest S0 galaxy, NGC 3115, along with implications for its assembly history. The data include high-quality wide-field imaging and multi-slit spectra of the field stars and globular clusters (GCs). Within two effective radii, the bulge (as traced by the stars and metal-rich GCs) is flattened and rotates rapidly. At larger radii, the rotation declines dramatically, while the characteristic GC metallicities also decrease with radius. We argue that this pattern is not naturally explained by a binary major merger, but instead by a two-phase assembly process where the inner regions have formed in an early violent, dissipative phase, followed by the protracted growth of the outer parts via minor mergers. To test this hypothesis
6. MALT90 Kinematic Distances to Dense Molecular Clumps
Energy Technology Data Exchange (ETDEWEB)
Whitaker, J. Scott [Physics Department, Boston University, 590 Commonwealth Avenue, Boston, MA 02215 (United States); Jackson, James M.; Sanhueza, Patricio; Stephens, Ian W. [Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States); Rathborne, J. M. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW 1710 (Australia); Foster, J. B. [Department of Astronomy, Yale University, P.O. Box 28101, New Haven, CT 06520-8101 (United States); Contreras, Y. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Longmore, S. N., E-mail: scott@bu.edu [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom)
2017-10-01
Using molecular-line data from the Millimetre Astronomy Legacy Team 90 GHz Survey (MALT90), we have estimated kinematic distances to 1905 molecular clumps identified in the ATLASGAL 870 μ m continuum survey over the longitude range 295° < l < 350°. The clump velocities were determined using a flux-weighted average of the velocities obtained from Gaussian fits to the HCO{sup +}, HNC, and N{sub 2}H{sup +} (1–0) transitions. The near/far kinematic distance ambiguity was addressed by searching for the presence or absence of absorption or self-absorption features in 21 cm atomic hydrogen spectra from the Southern Galactic Plane Survey. Our algorithm provides an estimation of the reliability of the ambiguity resolution. The Galactic distribution of the clumps indicates positions where the clumps are bunched together, and these locations probably trace the locations of spiral arms. Several clumps fall at the predicted location of the far side of the Scutum–Centaurus arm. Moreover, a number of clumps with positive radial velocities are unambiguously located on the far side of the Milky Way at galactocentric radii beyond the solar circle. The measurement of these kinematic distances, in combination with continuum or molecular-line data, now enables the determination of fundamental parameters such as mass, size, and luminosity for each clump.
7. Outflows in the narrow-line region of bright Seyfert galaxies - I. GMOS-IFU data
Science.gov (United States)
Freitas, I. C.; Riffel, R. A.; Storchi-Bergmann, T.; Elvis, M.; Robinson, A.; Crenshaw, D. M.; Nagar, N. M.; Lena, D.; Schmitt, H. R.; Kraemer, S. B.
2018-05-01
We present two-dimensional maps of emission-line fluxes and kinematics, as well as of the stellar kinematics of the central few kpc of five bright nearby Seyfert galaxies - Mrk 6, Mrk 79, Mrk 348, Mrk 607, and Mrk 1058 - obtained from observations with the Gemini Multi-Object Spectrograph Integral Field Unit on the Gemini North Telescope. The data cover the inner 3.5 arcsec × 5.0 arcsec - corresponding to physical scales in the range 0.6 × 0.9-1.5 × 2.2 kpc2 - at a spatial resolution ranging from 110 to 280 pc with a spectral coverage of 4300-7100 Å and velocity resolution of ≈90 km s-1. The gas excitation is Seyfert like everywhere but show excitation gradients that are correlated with the gas kinematics, reddening and/or the gas density. The gas kinematics show in all cases two components: a rotation one similar to that observed in the stellar velocity field, and an outflow component. In the case of Mrk607, the gas is counter-rotating relative to the stars. Enhanced gas velocity dispersion is observed in association with the outflows according to two patterns: at the locations of the highest outflow velocities along the ionization axis or perpendicularly to it in a strip centred at the nucleus that we attribute to an equatorial outflow. Bipolar outflows are observed in Mrk 348 and Mrk 79, while in Mrk 1058 only the blueshifted part is clearly observed, while in cases of Mrk 6 and Mrk 607, the geometry of the outflow needs further constraints from modelling to be presented in a forthcoming study, where the mass flow rate and powers will also be obtained.
8. IONIZED GAS KINEMATICS AT HIGH RESOLUTION. V. [Ne ii], MULTIPLE CLUSTERS, HIGH EFFICIENCY STAR FORMATION, AND BLUE FLOWS IN HE 2–10
International Nuclear Information System (INIS)
Beck, Sara; Turner, Jean; Lacy, John; Greathouse, Thomas
2015-01-01
We measured the 12.8 μm [Ne ii] line in the dwarf starburst galaxy He 2–10 with the high-resolution spectrometer TEXES on the NASA IRTF. The data cube has a diffraction-limited spatial resolution of ∼1″ and a total velocity resolution, including thermal broadening, of ∼5 km s −1 . This makes it possible to compare the kinematics of individual star-forming clumps and molecular clouds in the three dimensions of space and velocity, and allows us to determine star formation efficiencies. The kinematics of the ionized gas confirm that the starburst contains multiple dense clusters. From the M/R of the clusters and the ≃30%–40% star formation efficiencies, the clusters are likely to be bound and long lived, like globulars. Non-gravitational features in the line profiles show how the ionized gas flows through the ambient molecular material, as well as a narrow velocity feature, which we identify with the interface of the H ii region and a cold dense clump. These data offer an unprecedented view of the interaction of embedded H ii regions with their environment
9. Non-Maxwellian Analysis of the Transition-region Line Profiles Observed by the Interface Region Imaging Spectrograph
Energy Technology Data Exchange (ETDEWEB)
Dudík, Jaroslav; Dzifčáková, Elena [Astronomical Institute of the Czech Academy of Sciences, Fričova 298, 251 65 Ondřejov (Czech Republic); Polito, Vanessa; Testa, Paola [Smithsonian Astrophysical Observatory, 60 Garden Street, MS 58, Cambridge, MA 02138 (United States); Zanna, Giulio Del, E-mail: dudik@asu.cas.cz [Department of Applied Mathematics and Theoretical Physics, CMS, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2017-06-10
We investigate the nature of the spectral line profiles for transition-region (TR) ions observed with the Interface Region Imaging Spectrograph (IRIS) . In this context, we analyzed an active-region observation performed by IRIS in its 1400 Å spectral window. The TR lines are found to exhibit significant wings in their spectral profiles, which can be well fitted with a non-Maxwellian κ distribution. The fit with a κ distribution can perform better than a double-Gaussian fit, especially for the strongest line, Si iv 1402.8 Å. Typical values of κ found are about 2, occurring in a majority of spatial pixels where the TR lines are symmetric, i.e., the fit can be performed. Furthermore, all five spectral lines studied (from Si iv, O iv, and S iv) appear to have the same full-width at half-maximum irrespective of whether the line is an allowed or an intercombination transition. A similar value of κ is obtained for the electron distribution by the fitting of the line intensities relative to Si iv 1402.8 Å, if photospheric abundances are assumed. The κ distributions, however, do not remove the presence of non-thermal broadening. Instead, they actually increase the non-thermal width. This is because, for κ distributions, TR ions are formed at lower temperatures. The large observed non-thermal width lowers the opacity of the Si iv line sufficiently enough for this line to become optically thin.
10. A GMOS-N IFU study of the central H II region in the blue compact dwarf galaxy NGC 4449: kinematics, nebular metallicity and star formation
Science.gov (United States)
Kumari, Nimisha; James, Bethan L.; Irwin, Mike J.
2017-10-01
We use integral field spectroscopic (IFS) observations from the Gemini Multi-Object Spectrograph North (GMOS-N) to study the central H II region in a nearby blue compact dwarf (BCD) galaxy NGC 4449. The IFS data enable us to explore the variation of physical and chemical conditions of the star-forming region and the surrounding gas on spatial scales as small as 5.5 pc. Our kinematical analysis shows possible signatures of shock ionization and shell structures in the surroundings of the star-forming region. The metallicity maps of the region, created using direct Te and indirect strong line methods (R23, O3N2 and N2), do not show any chemical variation. From the integrated spectrum of the central H II region, we find a metallicity of 12 + log(O/H) = 7.88 ± 0.14 ({˜ }0.15^{+0.06}_{-0.04} Z⊙) using the direct method. Comparing the central H II region metallicity derived here with those of H II regions throughout this galaxy from previous studies, we find evidence of increasing metallicity with distance from the central nucleus. Such chemical inhomogeneities can be due to several mechanisms, including gas loss via supernova blowout, galactic winds or metal-poor gas accretion. However, we find that the localized area of decreased metallicity aligns spatially with the peak of star-forming activity in the galaxy, suggesting that gas accretion may be at play here. Spatially resolved IFS data for the entire galaxy are required to confirm the metallicity inhomogeneity found in this study and determine its possible cause.
11. TIMASSS: the IRAS 16293-2422 millimeter and submillimeter spectral survey. I. Observations, calibration, and analysis of the line kinematics
Science.gov (United States)
Caux, E.; Kahane, C.; Castets, A.; Coutens, A.; Ceccarelli, C.; Bacmann, A.; Bisschop, S.; Bottinelli, S.; Comito, C.; Helmich, F. P.; Lefloch, B.; Parise, B.; Schilke, P.; Tielens, A. G. G. M.; van Dishoeck, E.; Vastel, C.; Wakelam, V.; Walters, A.
2011-08-01
Context. Unbiased spectral surveys are powerful tools to study the chemistry and the physics of star forming regions, because they can provide a complete census of the molecular content and the observed lines probe the physical structure of the source. Aims: While unbiased surveys at the millimeter and sub-millimeter wavelengths observable from ground-based telescopes have previously been performed towards several high mass protostars, very little exists on low mass protostars, which are believed to resemble our own Sun's progenitor. To help fill up this gap in our understanding, we carried out a complete spectral survey of the bands at 3, 2, 1, and 0.9 mm towards the solar type protostar IRAS 16293-2422. Methods: The observations covered a range of about 200 GHz and were obtained with the IRAM-30 m and JCMT-15 m telescopes during about 300 h of observations. Particular attention was devoted to the inter-calibration of the acquired spectra with previous observations. All the lines detected with more than 3σ confidence-interval certainty and free from obvious blending effects were fitted with Gaussians to estimate their basic kinematic properties. Results: More than 4000 lines were detected (with σ ≥ 3) and identified, yielding a line density of approximatively 20 lines per GHz, comparable to previous surveys in massive hot cores. The vast majority (about two-thirds) of the lines are weak and produced by complex organic molecules. The analysis of the profiles of more than 1000 lines belonging to 70 species firmly establishes the presence of two distinct velocity components associated with the two objects, A and B, forming the IRAS 16293-2422 binary system. In the source A, the line widths of several species increase with the upper level energy of the transition, a behavior compatible with gas infalling towards a ~1 M⊙ object. The source B, which does not show this effect, might have a much lower central mass of ~0.1 M⊙. The difference in the rest velocities
12. Aperture synthesis observations of recombination lines from compact HII regions
International Nuclear Information System (INIS)
Gorkom, J.H. van.
1980-01-01
This thesis describes a continuation of early attempts to attain a high spectral dynamic range in general and to study recombination lines from compact HII regions in particular. These observations are made with the WSRT, until recently, the only instrument with sufficient angular resolution and sensitivity to provide at 6 cm detailed line maps of compact HII regions. An investigation into the spectral stability of the WSRT is described. Chromatic errors were found and their effects on maps are shown. These errors were found in the 80 channel filter spectrometer which was still in use at that time. The advent of the digital line backend (DLB) improved the dynamic range by an order of magnitude. An experiment is described which was partially aimed at testing the spectral stability of the DLB. It concerns a search for HI emission from the high velocity system of NGC 1275. Recombination line observations of the compact components in five giant HII regions are presented. The author discusses the radiative transfer problem in recombination lines and shows that non-LTE effects and pressure broadening can be of importance in compact HII regions. Observations obtained with the DLB are also presented. Because of the much better instrumental quality and improved insight into calibration procedures, mapping the H110α emission of DR21 and both the H110α and H166α emission of W3 was succeeded. (Auth.)
13. A projected back-tracking line-search for constrained interactive inverse kinematics
DEFF Research Database (Denmark)
Engell-Nørregård, Morten Pol; Erleben, Kenny
2011-01-01
Inverse kinematics is the problem of manipulating the pose of an articulated figure in order to achieve a desired goal disregarding inertia and forces. One can approach the problem as a non-linear optimization problem or as non-linear equation solving. The former approach is superior in its...... of joint limits in an interactive solver. This makes it possible to compute the pose in each frame without the discontinuities exhibited by existing key frame animation techniques....
14. Spectroscopic observations of Nova Cygni 1975: The coronal line region revisited
International Nuclear Information System (INIS)
Ferland, G.J.; Lambert, D.L.; Woodman, J.H.
1986-01-01
A synopsis of the McDonald Observatory spectrophotometric observations of Nova Cyg 1975 (V1500 Cyg) is presented. We present these data in a form in which they can be readily accessed in the future, and also study the continous spectrum during the early nebular phase. We show that (1) the remnant probably maintained a luminosity at or above the Eddington limit for at least a year after outburst, (2) free-free emission from the coronal line region made a significant contribution to the optical continuum, and (3) the coronal line region was probably a significant source of ionizing radiation. The energetics of this nova appear to be dominated by the lift-off energy from the white dwarf and radiation from the coronal line region. Thus the light curve of Nova Cyg may tell more about the cooling of the coronal line region than about the decline of the central object. In appendices we discuss the argon abundance of Nova Cyg (less than 8 times solar) and describe how to obtain copies of the McDonald nova data
15. The Southern HII Region Discovery Survey: Preliminary Results
Science.gov (United States)
Shea, Jeanine; Wenger, Trey; Balser, Dana S.; Anderson, Loren D.; Armentrout, William P.; Bania, Thomas M.; Dawson, Joanne; Miller Dickey, John; Jordan, Christopher; McClure-Griffiths, Naomi M.
2017-01-01
HII regions are some of the brightest sources at radio frequencies in the Milky Way and are the sites of massive O and B-type star formation. They have relatively short (Bank Telescope. Candidate HII regions were selected from mid-infrared emission coincident with radio continuum emission, and confirmed as HII regions by the detection of radio recombination lines. Here we discuss the Southern HII Region Discovery Survey (SHRDS), a continuation of the HRDS using the Australia Telescope Compact Array over the Galactic longitude range 230 to 360 degrees. We have reduced and analyzed a small sub-set of the SHRDS sources and discuss preliminary results, including kinematic distances and metallicities.
16. Inverse Kinematics for Industrial Robots using Conformal Geometric Algebra
Directory of Open Access Journals (Sweden)
2016-01-01
Full Text Available This paper shows how the recently developed formulation of conformal geometric algebra can be used for analytic inverse kinematics of two six-link industrial manipulators with revolute joints. The paper demonstrates that the solution of the inverse kinematics in this framework relies on the intersection of geometric objects like lines, circles, planes and spheres, which provides the developer with valuable geometric intuition about the problem. It is believed that this will be very useful for new robot geometries and other mechanisms like cranes and topside drilling equipment. The paper extends previous results on inverse kinematics using conformal geometric algebra by providing consistent solutions for the joint angles for the different configurations depending on shoulder left or right, elbow up or down, and wrist flipped or not. Moreover, it is shown how to relate the solution to the Denavit-Hartenberg parameters of the robot. The solutions have been successfully implemented and tested extensively over the whole workspace of the manipulators.
17. A SAMPLE OF SEYFERT-2 GALAXIES WITH ULTRALUMINOUS GALAXY-WIDE NARROW-LINE REGIONS: QUASAR LIGHT ECHOES?
International Nuclear Information System (INIS)
Schirmer, M.; Diaz, R.; Levenson, N. A.; Winge, C.; Holhjem, K.
2013-01-01
We report the discovery of Seyfert-2 galaxies in SDSS-DR8 with galaxy-wide, ultraluminous narrow-line regions (NLRs) at redshifts z = 0.2-0.6. With a space density of 4.4 Gpc –3 at z ∼ 0.3, these 'green beans' (GBs) are amongst the rarest objects in the universe. We are witnessing an exceptional and/or short-lived phenomenon in the life cycle of active galactic nuclei (AGNs). The main focus of this paper is on a detailed analysis of the GB prototype galaxy J2240–0927 (z = 0.326). Its NLR extends over 26 × 44 kpc and is surrounded by an extended NLR. With a total [O III] λ5008 luminosity of (5.7 ± 0.9) × 10 43 erg s –1 , this is one of the most luminous NLRs known around any type-2 galaxy. Using VLT/XSHOOTER, we show that the NLR is powered by an AGN, and we derive resolved extinction, density, and ionization maps. Gas kinematics is disturbed on a global scale, and high-velocity outflows are absent or faint. This NLR is unlike any other NLR or extended emission line region known. Spectroscopy with Gemini/GMOS reveals extended, high-luminosity [O III] emission also in other GBs. WISE 24 μm luminosities are 5-50 times lower than predicted by the [O III] fluxes, suggesting that the NLRs reflect earlier, very active quasar states that have strongly subsided in less than a galaxy's light-crossing time. These light echoes, or ionization echoes, are about 100 times more luminous than any other such echo known to date. X-ray data are needed for photoionization modeling and to verify the light echoes.
18. [NEII] Line Velocity Structure of Ultracompact HII Regions
Science.gov (United States)
Okamoto, Yoshiko K.; Kataza, Hirokazu; Yamashita, Takuya; Miyata, Takashi; Sako, Shigeyuki; Honda, Mitsuhiko; Onaka, Takashi; Fujiyoshi, Takuya
Newly formed massive stars are embedded in their natal molecular clouds and are observed as ultracompact HII regions. They emit strong ionic lines such as [NeII] 12.8 micron. Since Ne is ionized by UV photons of E>21.6eV which is higher than the ionization energy of hydrogen atoms the line probes the ionized gas near the ionizing stars. This enables to probe gas motion in the vicinity of recently-formed massive stars. High angular and spectral resolution observations of the [NeII] line will thus provide siginificant information on structures (e.g. disks and outflows) generated through massive star formation. We made [NeII] spectroscopy of ultracompact HII regions using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the 8.2m Subaru Telescope in July 2002. Spatial and spectral resolutions were 0.5"" and 10000 respectively. Among the targets G45.12+0.13 shows the largest spatial variation in velocity. The brightest area of G45.12+0.13 has the largest line width in the object. The total velocity deviation amounts to 50km/s (peak to peak value) in the observed area. We report the velocity structure of [NeII] emission of G45.12+0.13 and discuss the gas motion near the ionizing star.
19. Integrating concepts and skills: Slope and kinematics graphs
Science.gov (United States)
Tonelli, Edward P., Jr.
The concept of force is a foundational idea in physics. To predict the results of applying forces to objects, a student must be able to interpret data representing changes in distance, time, speed, and acceleration. Comprehension of kinematics concepts requires students to interpret motion graphs, where rates of change are represented as slopes of line segments. Studies have shown that majorities of students who show proficiency with mathematical concepts fail accurately to interpret motion graphs. The primary aim of this study was to examine how students apply their knowledge of slope when interpreting kinematics graphs. To answer the research questions a mixed methods research design, which included a survey and interviews, was adopted. Ninety eight (N=98) high school students completed surveys which were quantitatively analyzed along with qualitative information collected from interviews of students (N=15) and teachers ( N=2). The study showed that students who recalled methods for calculating slopes and speeds calculated slopes accurately, but calculated speeds inaccurately. When comparing the slopes and speeds, most students resorted to calculating instead of visual inspection. Most students recalled and applied memorized rules. Students who calculated slopes and speeds inaccurately failed to recall methods of calculating slopes and speeds, but when comparing speeds, these students connected the concepts of distance and time to the line segments and the rates of change they represented. This study's findings will likely help mathematics and science educators to better assist their students to apply their knowledge of the definition of slope and skills in kinematics concepts.
20. Thermal wind model for the broad emission line region of quasars
International Nuclear Information System (INIS)
Weymann, R.J.; Scott, J.S.; Schiano, A.V.R.; Christiansen, W.A.
1982-01-01
Arguments are summarized for supposing that the clouds giving rise to the broad emission lines of QSOs are confined by the pressure of an expanding thermal gas and that a flux of relativistic particles with luminosity comparable to the photon luminosity streams through this gas. The resulting heating and momentum deposition produces a transonic thermal wind whose dynamical properties are calculated in detail. This wind accelerates and confines the emission line clouds, thereby producing the broad emission line (BEL) profiles. In a companion paper, the properties of the wind at much larger distances (approx.kpc) than the BEL region are used to explain the production of the broad absorption lines (BAL) observed in some QSOs. The same set of wind parameters can account for the properties of both the BEL and BAL regions, and this unification in the physical description of the BEL and BAL regions is one of the most important advantages of this model. A characteristic size of approx.1 pc for the QSO emission line region is one consequence of the model. This characteristic size is shown to depend upon luminosity in such a way that the ionization parameter is roughly constant over a wide range of luminosities. An X-ray luminosity due to thermal bremsstrahlung of approx.1%--10% of the optical luminosity is another consequence of the model. The trajectories of clouds under the combined influence of ram pressure acceleration and radiative acceleration are calculated. From these trajectories emission line profiles are also calculated, as well as the wind and cloud parameters yielding profiles in fair agreement with observed profiles explored. Opacity in the wind due to electron scattering displaces the line cores of optically thin lines to the blue. This is roughly compensated for by the redward skewing of optically thick lines due to preferential emission of photons from the back side of the clouds.void rapid depletion due to Compton losses are discussed
1. Mechanical versus kinematical shortening reconstructions of the Zagros High Folded Zone (Kurdistan region of Iraq)
Science.gov (United States)
Frehner, Marcel; Reif, Daniel; Grasemann, Bernhard
2012-06-01
This paper compares kinematical and mechanical techniques for the palinspastic reconstruction of folded cross sections in collision orogens. The studied area and the reconstructed NE-SW trending, 55.5 km long cross section is located in the High Folded Zone of the Zagros fold-and-thrust belt in the Kurdistan region of Iraq. The present-day geometry of the cross section has been constructed from field as well as remote sensing data. In a first step, the structures and the stratigraphy are simplified and summarized in eight units trying to identify the main geometric and mechanical parameters. In a second step, the shortening is kinematically estimated using the dip domain method to 11%-15%. Then the same cross section is used in a numerical finite element model to perform dynamical unfolding simulations taking various rheological parameters into account. The main factor allowing for an efficient dynamic unfolding is the presence of interfacial slip conditions between the mechanically strong units. Other factors, such as Newtonian versus power law viscous rheology or the presence of a basement, affect the numerical simulations much less strongly. If interfacial slip is accounted for, fold amplitudes are reduced efficiently during the dynamical unfolding simulations, while welded layer interfaces lead to unrealistic shortening estimates. It is suggested that interfacial slip and decoupling of the deformation along detachment horizons is an important mechanical parameter that controlled the folding processes in the Zagros High Folded Zone.
2. Kinematics in special and general relativity
International Nuclear Information System (INIS)
Woodside, R.W.M.
1979-05-01
This thesis investigates the problem of motion for extended bodies from the viewpoint of classical field theory, where the classical field is the body's energy-momentum or matter tensor. In special relativity a symmetric and divergence-free matter tensor combined with inertial frames is used to generate a kinematics for extended bodies. In general relativity the author suggests an analogous kinematics and applies it to the simplest non-trivial example of static, spherical stars, looking for special sets of vector fields whose matter currents are conserved. Such a set of ten vector fields defines a special frame, and integrals of the conserved matter currents define ten momenta whcih give the kinematics. Application of de Rham cohomology theory shows that the conserved matter currents for isolated bodies will have mechanical potentials which enable the momenta to be found from flux integrals evaluated in the vacuum region surrounding the body. These potentials contain the full Riemann curvature, allowing a body's general relativistic momenta to be determined by its vacuum graviational field
3. Kinematics analysis of a novel planar parallel manipulator with kinematic redundancy
Energy Technology Data Exchange (ETDEWEB)
Qu, Haibo; Guo, Sheng [Beijing Jiaotong University, Beijing (China)
2017-04-15
In this paper, a novel planar parallel manipulator with kinematic redundancy is proposed. First, the Degrees of freedom (DOF) of the whole parallel manipulator and the Relative DOF (RDOF) between the moving platform and fixed base are studied. The results indicate that the proposed mechanism is kinematically redundant. Then, the kinematics, Jacobian matrices and workspace of this proposed parallel manipulator with kinematic redundancy are analyzed. Finally, the statics simulation of the proposed parallel manipulator is performed. The obtained stress and displacement distribution can be used to determine the easily destroyed place in the mechanism configurations.
4. Kinematics analysis of a novel planar parallel manipulator with kinematic redundancy
International Nuclear Information System (INIS)
Qu, Haibo; Guo, Sheng
2017-01-01
In this paper, a novel planar parallel manipulator with kinematic redundancy is proposed. First, the Degrees of freedom (DOF) of the whole parallel manipulator and the Relative DOF (RDOF) between the moving platform and fixed base are studied. The results indicate that the proposed mechanism is kinematically redundant. Then, the kinematics, Jacobian matrices and workspace of this proposed parallel manipulator with kinematic redundancy are analyzed. Finally, the statics simulation of the proposed parallel manipulator is performed. The obtained stress and displacement distribution can be used to determine the easily destroyed place in the mechanism configurations
5. X-ray Emission Line Spectroscopy of Nearby Galaxies
Science.gov (United States)
Wang, Daniel
What are the origins of the diffuse soft X-ray emission from non-AGN galaxies? Preliminary analysis of XMM-Newton RGS spectra shows that a substantial fraction of the emission cannot arise from optically-thin thermal plasma, as commonly assumed, and may originate in charge exchange at the interface with neutral gas. We request the support for a comprehensive observing, data analysis, and modeling program to spectroscopically determine the origins of the emission. First, we will use our scheduled XMM-Newton AO-10 368 ks observations of the nearest compact elliptical galaxy M32 to obtain the first spectroscopic calibration of the cumulative soft X-ray emission from the old stellar population and will develop a spectral model for the charge exchange, as well as analysis tools to measure the spatial and kinematic properties of the X-ray line- emitting plasma. Second, we will characterize the truly diffuse emission from the hot plasma and/or its interplay with the neutral gas in a sample of galactic spheroids and active star forming/starburst regions in nearby galaxies observed by XMM-Newton. In particular, we will map out the spatial distributions of key emission lines and measure (or tightly constrain) the kinematics of hot plasma outflows for a few X-ray-emitting regions with high-quality RGS data. For galaxies with insufficient counting statistics in individual emission lines, we will conduct a spectral stacking analysis to constrain the average properties of the X-ray-emitting plasma. We will use the results of these X-ray spectroscopic analyses, together with complementary X-ray CCD imaging/spectral data and observations in other wavelength bands, to test the models of the emission. In addition to the charge exchange, alternative scenarios such as resonance scattering and relic AGN photo-ionization will also be examined for suitable regions. These studies are important to the understanding of the relationship between the diffuse soft X-ray emission and various
6. Self-Consistent Dynamical Model of the Broad Line Region
Energy Technology Data Exchange (ETDEWEB)
Czerny, Bozena [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Li, Yan-Rong [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Sredzinska, Justyna; Hryniewicz, Krzysztof [Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Panda, Swayam [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Wildy, Conor [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Karas, Vladimir, E-mail: bcz@cft.edu.pl [Astronomical Institute, Czech Academy of Sciences, Prague (Czech Republic)
2017-06-22
We develop a self-consistent description of the Broad Line Region based on the concept of a failed wind powered by radiation pressure acting on a dusty accretion disk atmosphere in Keplerian motion. The material raised high above the disk is illuminated, dust evaporates, and the matter falls back toward the disk. This material is the source of emission lines. The model predicts the inner and outer radius of the region, the cloud dynamics under the dust radiation pressure and, subsequently, the gravitational field of the central black hole, which results in asymmetry between the rise and fall. Knowledge of the dynamics allows us to predict the shapes of the emission lines as functions of the basic parameters of an active nucleus: black hole mass, accretion rate, black hole spin (or accretion efficiency) and the viewing angle with respect to the symmetry axis. Here we show preliminary results based on analytical approximations to the cloud motion.
7. Self-Consistent Dynamical Model of the Broad Line Region
Directory of Open Access Journals (Sweden)
Bozena Czerny
2017-06-01
Full Text Available We develop a self-consistent description of the Broad Line Region based on the concept of a failed wind powered by radiation pressure acting on a dusty accretion disk atmosphere in Keplerian motion. The material raised high above the disk is illuminated, dust evaporates, and the matter falls back toward the disk. This material is the source of emission lines. The model predicts the inner and outer radius of the region, the cloud dynamics under the dust radiation pressure and, subsequently, the gravitational field of the central black hole, which results in asymmetry between the rise and fall. Knowledge of the dynamics allows us to predict the shapes of the emission lines as functions of the basic parameters of an active nucleus: black hole mass, accretion rate, black hole spin (or accretion efficiency and the viewing angle with respect to the symmetry axis. Here we show preliminary results based on analytical approximations to the cloud motion.
8. Relativistic Kinematics
OpenAIRE
Sahoo, Raghunath
2016-01-01
This lecture note covers Relativistic Kinematics, which is very useful for the beginners in the field of high-energy physics. A very practical approach has been taken, which answers "why and how" of the kinematics useful for students working in the related areas.
9. Argument for a non-standard broad-line region
International Nuclear Information System (INIS)
Collin, S.
1987-01-01
The region emitting the broad lines (BLR) in quasars and AGN has a ''Standard Status''. It is shown that this status raises strong problems concerning the energetic budget and the thermal state of the BLR. A possible solution is proposed [fr
10. Modeling and interpretation of line observations*
Directory of Open Access Journals (Sweden)
Kamp Inga
2015-01-01
Full Text Available Models for the interpretation of line observations from protoplanetary disks are summarized. The spectrum ranges from 1D LTE slab models to 2D thermo-chemical radiative transfer models and their use depends largely on the type/nature of observational data that is analyzed. I discuss the various types of observational data and their interpretation in the context of disk physical and chemical properties. The most simple spatially and spectral unresolved data are line fluxes, which can be interpreted using so-called Boltzmann diagrams. The interpretation is often tricky due to optical depth and non-LTE effects and requires care. Line profiles contain kinematic information and thus indirectly the spatial origin of the emission. Using series of line profiles, we can for example deduce radial temperature gradients in disks (CO pure rotational ladder. Spectro-astrometry of e.g. CO ro-vibrational line profiles probes the disk structure in the 1–30 AU region, where planet formation through core accretion should be most efficient. Spatially and spectrally resolved line images from (submm interferometers are the richest datasets we have to date and they enable us to unravel exciting details of the radial and vertical disk structure such as winds and asymmetries.
11. VizieR Online Data Catalog: The kinematics of the C II λ6578 line in PNe (Richer+, 2017)
Science.gov (United States)
Richer, M. G.; Suarez, G.; Lopez, J. A.; Garcia Diaz, M. T.
2018-05-01
All of our observations are drawn from the San Pedro Martir Kinematic Catalogue of Planetary Nebulae (henceforth, SPM Catalogue; Lopez et al. 2012RMxAA..48....3L; http://kincatpn.astrosen.unam.mx/). Most of these spectra were acquired with the Manchester Echelle Spectrograph (MES: Meaburn et al. 1984MNRAS.210..463M, 2003RMxAA..39..185M) attached to the 2.1 m telescope at the Observatorio Astronomico Nacional on the Sierra San Pedro Martir (OAN-SPM). The MES uses interference filters to isolate the spectral order of interest, order 87 in this case, covering approximately the wavelength range 6545-6595 Å and containing the [N II] λλ6548, 6584, He II λ6560 (when present), Hα, and C II λ6578 emission lines. For most of the observations, a 150 μm slit was used, resulting in a spectral resolution of approximately 11 km/s when converted to velocity. (2 data files).
12. Kinematical Comparison of the 200 m Backstroke Turns between National and Regional Level Swimmers
Directory of Open Access Journals (Sweden)
Santiago Veiga
2013-12-01
Full Text Available The aims of this investigation were to determine the evolution of selected turn variables during competitive backstroke races and to compare these kinematic variables between two different levels of swimmers. Sixteen national and regional level male swimmers participant in the 200 m backstroke event at the Spanish Swimming Championships in short course (25 m were selected to analyze their turn performances. The individual distances method with two-dimensional Direct Linear Transformation (2D-DLT algorithms was used to perform race analyses. National level swimmers presented a shorter “turn time”, a longer “distance in”, a faster “underwater velocity” and “normalized underwater velocity”, and a faster “stroking velocity” than regional level swimmers, whereas no significant differences were detected between levels for the “underwater distance”. National level swimmers maintained similar “turn times” over the event and increased “underwater velocity” and “normalized underwater velocity” in the last (seventh turn segment, whereas regional level swimmers increased “turn time” in the last half of the race. For both national and regional level swimmers, turn “underwater distance” during the last three turns of the race was significantly shorter while no significant differences in distance into the wall occurred throughout the race. The skill level of the swimmers has an impact on the competitive backstroke turn segments. In a 200 m event, the underwater velocity should be maximized to maintain turn proficiency, whereas turn distance must be subordinated to the average velocity.
13. Rational kinematics
CERN Document Server
Angeles, Jorge
1988-01-01
A rational study of kinematics is a treatment of the subject based on invariants, i.e., quantities that remain essentially unchanged under a change of observer. An observer is understood to be a reference frame supplied with a clock (Truesdell 1966). This study will therefore include an introduction to invariants. The language of these is tensor analysis and multilinear algebra, both of which share many isomorphic relations, These subjects are treated in full detail in Ericksen (1960) and Bowen and Wang (1976), and hence will not be included here. Only a short account of notation and definitions will be presented. Moreover, definitions and basic concepts pertaining to the kinematics of rigid bodies will be also included. Although the kinematics of rigid bodies can be regarded as a particular case of the kinematics of continua, the former deserves attention on its own merits for several reasons. One of these is that it describes locally the motions undergone by continua. Another reason is that a whole area of ...
14. Small-scale kinematic dynamo and non-dynamo in inertial-range turbulence
International Nuclear Information System (INIS)
Eyink, Gregory L; Neto, Antonio F
2010-01-01
We investigate the Lagrangian mechanism of the kinematic 'fluctuation' magnetic dynamo in a turbulent plasma flow at small magnetic Prandtl numbers. The combined effect of turbulent advection and plasma resistivity is to carry infinitely many field lines to each space point, with the resultant magnetic field at that point given by the average over all the individual line vectors. As a consequence of the roughness of the advecting velocity, this remains true even in the limit of zero resistivity. We show that the presence of the dynamo effect requires sufficient angular correlation of the passive line vectors that arrive simultaneously at the same space point. We illustrate this in detail for the Kazantsev-Kraichnan model of the kinematic dynamo with a Gaussian advecting velocity that is spatially rough and white noise in time. In the regime where dynamo action fails, we also obtain the precise rate of decay of the magnetic energy. These exact results for the model are obtained by a generalization of the 'slow-mode expansion' of Bernard, Gawedzki and Kupiainen to non-Hermitian evolution. Much of our analysis applies also to magnetohydrodynamic turbulence.
15. Microphysical and Kinematic Characteristics of Regions of Flash Initiation in a Supercell Storm and a Multicell Storm Observed During the DC3 Field Program
Science.gov (United States)
DiGangi, E.; MacGorman, D. R.; Ziegler, C.; Betten, D.; Biggerstaff, M. I.
2017-12-01
Lightning initiation in thunderstorms requires that the local electric field magnitude exceed breakdown values somewhere, and this tends to occur between regions of positive and negative charge, where the largest electric field magnitudes tend to occur. Past studies have demonstrated that, near updrafts, storms with very strong updrafts tend to elevate regions of charge and of flash initiations higher, as well as to have more flashes initiated by small pockets of charge, than in storms with much weaker updrafts. In all thunderstorms, the source of these charge regions is generally thought to be microscopic charge separation via the relative growth rate noninductive mechanism, followed by macroscopic charge separation via sedimentation, although other charge generation mechanisms can contribute to charge in some regions. Charge generation and lightning initiation are therefore inherently dependent on the microphysical and kinematic characteristics of a given storm. This study compares the results of a hydrometeor classification algorithm applied to C-band mobile radar data with mixing ratios calculated by a diabatic Lagrangian analysis retrieval from the dual-Doppler wind fields for two storms, the 29-30 May 2012 supercell storm and the 21 June 2012 multicell storm, observed during the Deep Convective Clouds and Chemistry experiment. Using these data, we then compare the inferred microphysical and kinematic characteristics of regions in which the Oklahoma Lightning Mapping Array indicated that flashes were initiated in these two very different storms.
16. Design, Modeling and Control of a Biped Line-Walking Robot
Directory of Open Access Journals (Sweden)
Ludan Wang
2010-12-01
Full Text Available The subject of this paper is the design and analysis of a biped line walking robot for inspection of power transmission lines. With a novel mechanism the centroid of the robot can be concentrated on the axis of hip joint to minimize the drive torque of the hip joint. The mechanical structure of the robot is discussed, as well as forward kinematics. Dynamic model is established in this paper to analyze the inverse kinematics for motion planning. The line-walking cycle of the line-walking robot is composed of a single-support phase and a double-support phase. Locomotion of the line-walking robot is discussed in details and the obstacle-navigation process is planed according to the structure of power transmission line. To fulfill the demands of line-walking, a control system and trajectories generation method are designed for the prototype of the line-walking robot. The feasibility of this concept is then confirmed by performing experiments with a simulated line environment.
17. WHY IS NON-THERMAL LINE BROADENING OF SPECTRAL LINES IN THE LOWER TRANSITION REGION OF THE SUN INDEPENDENT OF SPATIAL RESOLUTION?
International Nuclear Information System (INIS)
De Pontieu, B.; Martinez-Sykora, J.; McIntosh, S.; Peter, H.; Pereira, T. M. D.
2015-01-01
Spectral observations of the solar transition region (TR) and corona show broadening of spectral lines beyond what is expected from thermal and instrumental broadening. The remaining non-thermal broadening is significant (5–30 km s −1 ) and correlated with intensity. Here we study spectra of the TR Si iv 1403 Å line obtained at high resolution with the Interface Region Imaging Spectrograph (IRIS). We find that the large improvement in spatial resolution (0.″33) of IRIS compared to previous spectrographs (2″) does not resolve the non-thermal line broadening which, in most regions, remains at pre-IRIS levels of about 20 km s −1 . This invariance to spatial resolution indicates that the processes behind the broadening occur along the line-of-sight (LOS) and/or on spatial scales (perpendicular to the LOS) smaller than 250 km. Both effects appear to play a role. Comparison with IRIS chromospheric observations shows that, in regions where the LOS is more parallel to the field, magneto-acoustic shocks driven from below impact the TR and can lead to significant non-thermal line broadening. This scenario is supported by MHD simulations. While these do not show enough non-thermal line broadening, they do reproduce the long-known puzzling correlation between non-thermal line broadening and intensity. This correlation is caused by the shocks, but only if non-equilibrium ionization is taken into account. In regions where the LOS is more perpendicular to the field, the prevalence of small-scale twist is likely to play a significant role in explaining the invariance and correlation with intensity. (letters)
18. Ultraviolet interstellar absorption toward stars in the small Magellanic Cloud. III. THe structure and kinematics of Small Magellanic Cloud
International Nuclear Information System (INIS)
Fitzpatrick, A.L.
1985-01-01
The structure and kinematical properties of the Small Magellanic Cloud (SMC) are investigated by combining ultraviolet data obtained from the International Ultraviolet Explorer (IUE) satellite with existing optical and radio data. The SMC structure is complicated, undoubtedly a result of gravitational interaction with the Milky Way and the Large Magellanic Cloud, and is poorly understood. It has been known for some time that most of the H I in the SMC is concentrated in two complexes at velocities of approximately 134 and 167 km s -1 (heliocentric). Recent 21 cm emission surveys have revealed two additional, widespread H I components at approx.100 and approx.200 km s -1 . With the radio data alone, however, the relative line-of-sight locations of those complexes cannot be determined, nor can the associations of stars with the complexes be deduced. By using the ultraviolet interstellar absorption-line data in conjunction with radio and optical data, the stellar-interstellar kinematical and morphological relationships can be established. We find that in the southwest region of the SMC, most of the stars observed by IUE, including a group with only low-dispersion IUE spectra, are associated with the 134 km s -1 H I complex
19. Molecular and Recombination Lines in the Central Region of Sagittarius B2
Science.gov (United States)
Curtis, J.; Langston, G.
2005-12-01
We present observations of recombination and molecular lines towards Sgr B2 in the frequency range 12.4 to 15.0 GHz. In this frequency range, Hα , β , and γ lines, Heα recombination lines and emission from the SO molecule are detected. Molecular absorption lines from OH, H2CO, and CH3CO are detected at velocity 62±3 km/s. Measurements of the line widths and intensities are presented for the central region of Sgr B2. We detect two previously un-reported molecular absorption lines at 12388.0 and 14625.8 MHz (v=0. in LSR Frame). For selected recombination and molecular lines, we present images of a 10x10 arc-minute region centered on Sgr B2(M). We discuss the sources of three H2CO absorption features detected at 62±3, 6±5, and 100±10 km/s. This was done as a summer REU project in 2005 at the National Radio Astronomy Observatory's Green Bank site, and was funded by the National Science Foundation's REU program.
20. THE ORIGIN AND KINEMATICS OF COLD GAS IN GALACTIC WINDS: INSIGHT FROM NUMERICAL SIMULATIONS
International Nuclear Information System (INIS)
Fujita, Akimi; Martin, Crystal L.; Low, Mordecai-Mark Mac; New, Kimberly C. B.; Weaver, Robert
2009-01-01
We study the origin of Na I-absorbing gas in ultraluminous infrared galaxies motivated by the recent observations by Martin of extremely superthermal linewidths in this cool gas. We model the effects of repeated supernova explosions driving supershells in the central regions of molecular disks with M d = 10 10 M sun , using cylindrically symmetric gas dynamical simulations run with ZEUS-3D. The shocked swept-up shells quickly cool and fragment by Rayleigh-Taylor (R-T) instability as they accelerate out of the dense, stratified disks. The numerical resolution of the cooling and compression at the shock fronts determines the peak shell density, and so the speed of R-T fragmentation. We identify cooled shells and shell fragments as Na I-absorbing gas and study its kinematics along various sightlines across the grid. We find that simulations with a numerical resolution of ≤0.2 pc produce multiple R-T fragmented shells in a given line of sight that appear to explain the observed kinematics. We suggest that the observed wide Na I absorption lines, (v) = 320 ± 120 km s -1 , are produced by these multiple fragmented shells traveling at different velocities. We also suggest that some shell fragments can be accelerated above the observed average terminal velocity of 750 km s -1 by the same energy-driven wind with an instantaneous starburst of ∼10 9 M sun . The mass carried by these fragments is only a small fraction of the total shell mass, while the bulk of mass is traveling with velocities consistent with the observed average shell velocity 330 ± 100 km s -1 . Our results show that an energy-driven bubble causing R-T instabilities can explain the kinematics of cool gas seen in the Na I observations without invoking additional physics relying primarily on momentum conservation, such as entrainment of gas by Kelvin-Helmholtz instabilities, ram pressure driving of cold clouds by a hot wind, or radiation pressure acting on dust.
1. Morphology of AGN Emission Line Regions in SDSS-IV MaNGA Survey
Science.gov (United States)
He, Zhicheng; Sun, Ai-Lei; Zakamska, Nadia L.; Wylezalek, Dominika; Kelly, Michael; Greene, Jenny E.; Rembold, Sandro B.; Riffel, Rogério; Riffel, Rogemar A.
2018-05-01
Extended narrow-line regions (NLRs) around active galactic nuclei (AGN) are shaped by the distribution of gas in the host galaxy and by the geometry of the circumnuclear obscuration, and thus they can be used to test the AGN unification model. In this work, we quantify the morphologies of the narrow-line regions in 308 nearby AGNs (z = 0 - 0.14, Lbol˜1042.4 - 44.1 erg s-1) from the MaNGA survey. Based on the narrow-line region maps, we find that a large fraction (81%) of these AGN have bi-conical NLR morphology. The distribution of their measured opening angles suggests that the intrinsic opening angles of the ionization cones has a mean value of 85-98° with a finite spread of 39-44° (1-σ). Our inferred opening angle distribution implies a number ratio of type I to type II AGN of 1:1.6-2.3, consistent with other measurements of the type I / type II ratio at low AGN luminosities. Combining these measurements with the WISE photometry data, we find that redder mid-IR color (lower effective temperature of dust) corresponds to stronger and narrower photo-ionized bicones. This relation is in agreement with the unification model that suggests that the bi-conical narrow-line regions are shaped by a toroidal dusty structure within a few pc from the AGN. Furthermore, we find a significant alignment between the minor axis of host galaxy disks and AGN ionization cones. Together, these findings suggest that obscuration on both circumnuclear (˜pc) and galactic (˜ kpc) scales are important in shaping and orienting the AGN narrow-line regions.
2. Probing the Physics of Narrow-line Regions in Active Galaxies. IV. Full Data Release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)
Energy Technology Data Exchange (ETDEWEB)
Thomas, Adam D.; Dopita, Michael A.; Davies, Rebecca; Hampton, Elise; Kewley, Lisa; Banfield, Julie; Groves, Brent; Sutherland, Ralph [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Shastri, Prajval; Sairam, Lalitha [Indian Institute of Astrophysics, Sarjapur Road, Bengaluru 560034 (India); James, Bethan L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Jin, Chichuan [Max-Planck-Institut für Extraterrestrische Physik, Garching (Germany); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Kharb, Preeti [National Centre for Radio Astrophysics—Tata Institute of Fundamental Research, Pune University Campus, Post Bag 3, Ganeshkhind Pune 411007 (India); Scharwächter, Julia [Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, Hawaii 96720 (United States); Shalima, P. [Regional Institute of Education, Manasagangotri, Mysore 570006 (India); Sundar, M. N. [Jain University, 3rd Block Jayanagar, Bengaluru 560011 (India); Zaw, Ingyin, E-mail: adam.thomas@anu.edu.au [New York University (Abu Dhabi), 70 Washington Sq. S, New York, NY 10012 (United States)
2017-09-01
We present the second and final data release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). Data are presented for 63 new galaxies not included in the first data release, and we provide 2D emission-line fitting products for the full S7 sample of 131 galaxies. The S7 uses the WiFeS instrument on the ANU 2.3 m telescope to obtain spectra with a spectral resolution of R = 7000 in the red (540–700 nm) and R = 3000 in the blue (350–570 nm), over an integral field of 25 × 38 arcsec{sup 2} with 1 × 1 arcsec{sup 2} spatial pixels. The S7 contains both the largest sample of active galaxies and the highest spectral resolution of any comparable integral field survey to date. The emission-line fitting products include line fluxes, velocities, and velocity dispersions across the WiFeS field of view, and an artificial neural network has been used to determine the optimal number of Gaussian kinematic components for emission-lines in each spaxel. Broad Balmer lines are subtracted from the spectra of nuclear spatial pixels in Seyfert 1 galaxies before fitting the narrow lines. We bin nuclear spectra and measure reddening-corrected nuclear fluxes of strong narrow lines for each galaxy. The nuclear spectra are classified on optical diagnostic diagrams, where the strength of the coronal line [Fe vii] λ 6087 is shown to be correlated with [O iii]/H β . Maps revealing gas excitation and kinematics are included for the entire sample, and we provide notes on the newly observed objects.
3. The EDGE-CALIFA survey: validating stellar dynamical mass models with CO kinematics
Science.gov (United States)
Leung, Gigi Y. C.; Leaman, Ryan; van de Ven, Glenn; Lyubenova, Mariya; Zhu, Ling; Bolatto, Alberto D.; Falcón-Barroso, Jesus; Blitz, Leo; Dannerbauer, Helmut; Fisher, David B.; Levy, Rebecca C.; Sanchez, Sebastian F.; Utomo, Dyas; Vogel, Stuart; Wong, Tony; Ziegler, Bodo
2018-06-01
Deriving circular velocities of galaxies from stellar kinematics can provide an estimate of their total dynamical mass, provided a contribution from the velocity dispersion of the stars is taken into account. Molecular gas (e.g. CO), on the other hand, is a dynamically cold tracer and hence acts as an independent circular velocity estimate without needing such a correction. In this paper, we test the underlying assumptions of three commonly used dynamical models, deriving circular velocities from stellar kinematics of 54 galaxies (S0-Sd) that have observations of both stellar kinematics from the Calar Alto Legacy Integral Field Area (CALIFA) survey, and CO kinematics from the Extragalactic Database for Galaxy Evolution (EDGE) survey. We test the asymmetric drift correction (ADC) method, as well as Jeans, and Schwarzschild models. The three methods each reproduce the CO circular velocity at 1Re to within 10 per cent. All three methods show larger scatter (up to 20 per cent) in the inner regions (R < 0.4Re) that may be due to an increasingly spherical mass distribution (which is not captured by the thin disc assumption in ADC), or non-constant stellar M/L ratios (for both the JAM and Schwarzschild models). This homogeneous analysis of stellar and gaseous kinematics validates that all three models can recover Mdyn at 1Re to better than 20 per cent, but users should be mindful of scatter in the inner regions where some assumptions may break down.
4. THE NATURE OF ACTIVE GALACTIC NUCLEI WITH VELOCITY OFFSET EMISSION LINES
Energy Technology Data Exchange (ETDEWEB)
Müller-Sánchez, F.; Comerford, J. [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Harrison, F. A. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
2016-10-10
We obtained Keck/OSIRIS near-IR adaptive optics-assisted integral-field spectroscopy to probe the morphology and kinematics of the ionized gas in four velocity-offset active galactic nuclei (AGNs) from the Sloan Digital Sky Survey. These objects possess optical emission lines that are offset in velocity from systemic as measured from stellar absorption features. At a resolution of ∼0.″18, OSIRIS allows us to distinguish which velocity offset emission lines are produced by the motion of an AGN in a dual supermassive black hole system, and which are produced by outflows or other kinematic structures. In three galaxies, J1018+2941, J1055+1520, and J1346+5228, the spectral offset of the emission lines is caused by AGN-driven outflows. In the remaining galaxy, J1117+6140, a counterrotating nuclear disk is observed that contains the peak of Pa α emission 0.″2 from the center of the galaxy. The most plausible explanation for the origin of this spatially and kinematically offset peak is that it is a region of enhanced Pa α emission located at the intersection zone between the nuclear disk and the bar of the galaxy. In all four objects, the peak of ionized gas emission is not spatially coincident with the center of the galaxy as traced by the peak of the near-IR continuum emission. The peaks of ionized gas emission are spatially offset from the galaxy centers by 0.″1–0.″4 (0.1–0.7 kpc). We find that the velocity offset originates at the location of this peak of emission, and the value of the offset can be directly measured in the velocity maps. The emission-line ratios of these four velocity-offset AGNs can be reproduced only with a mixture of shocks and AGN photoionization. Shocks provide a natural explanation for the origin of the spatially and spectrally offset peaks of ionized gas emission in these galaxies.
5. Peculiar A star HD 43819 - A photographic region line-identification study
International Nuclear Information System (INIS)
1985-01-01
A line identification study of the sharp-lined silicon star HD 43819 has been performed for the photographic region 3759-4924 A. Comparison of this star's spectrum with those of other silicon stars shows that it shares many of their apparent abundance anomalies. The TiII, CrII, FeI, and FeII spectra are well represented while the singly ionized rare earths are represented by at best a few lines per species. 21 references
6. THE KINEMATICS OF THE NEBULAR SHELLS AROUND LOW MASS PROGENITORS OF PNe WITH LOW METALLICITY
Energy Technology Data Exchange (ETDEWEB)
Pereyra, Margarita; López, José Alberto; Richer, Michael G., E-mail: mally@astrosen.unam.mx, E-mail: jal@astrosen.unam.mx, E-mail: richer@astrosen.unam.mx [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 106, C.P. 22800 Ensenada, BC, México (Mexico)
2016-03-15
We analyze the internal kinematics of 26 planetary nebulae (PNe) with low metallicity that appear to derive from progenitor stars of the lowest masses, including the halo PN population. Based upon spatially resolved, long-slit, echelle spectroscopy drawn from the San Pedro Mártir Kinematic Catalog of PNe, we characterize the kinematics of these PNe measuring their global expansion velocities based upon the largest sample used to date for this purpose. We find kinematics that follow the trends observed and predicted in other studies, but also find that most of the PNe studied here tend to have expansion velocities less than 20 km s{sup −1} in all of the emission lines considered. The low expansion velocities that we observe in this sample of low metallicity PNe with low mass progenitors are most likely a consequence of a weak central star (CS) wind driving the kinematics of the nebular shell. This study complements previous results that link the expansion velocities of the PN shells with the characteristics of the CS.
7. WEAK LINE QUASARS AT HIGH REDSHIFT: EXTREMELY HIGH ACCRETION RATES OR ANEMIC BROAD-LINE REGIONS?
International Nuclear Information System (INIS)
Shemmer, Ohad; Trakhtenbrot, Benny; Netzer, Hagai; Anderson, Scott F.; Brandt, W. N.; Schneider, Donald P.; Diamond-Stanic, Aleksandar M.; Fan Xiaohui; Lira, Paulina; Plotkin, Richard M.; Richards, Gordon T.; Strauss, Michael A.
2010-01-01
We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad Hβ line and place tight upper limits on the strengths of their [O III] lines. Virial, Hβ-based black hole mass determinations indicate normalized accretion rates of L/L Edd =0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of Γ = 1.91 +0.24 -0.22 , which supports the virial L/L Edd determination in this source. Our results suggest that the weakness of the broad emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.
8. The dependence of C IV broad absorption line properties on accompanying Si IV and Al III absorption: relating quasar-wind ionization levels, kinematics, and column densities
Energy Technology Data Exchange (ETDEWEB)
Filiz Ak, N.; Brandt, W. N.; Schneider, D. P.; Trump, J. R. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3 (Canada); Anderson, S. F. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Hamann, F. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Pâris, I. [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Petitjean, P. [Institut d' Astrophysique de Paris, Universite Paris 6, F-75014 Paris (France); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Shen, Yue [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); York, Don, E-mail: nfilizak@astro.psu.edu [Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 (United States)
2014-08-20
We consider how the profile and multi-year variability properties of a large sample of C IV Broad Absorption Line (BAL) troughs change when BALs from Si IV and/or Al III are present at corresponding velocities, indicating that the line of sight intercepts at least some lower ionization gas. We derive a number of observational results for C IV BALs separated according to the presence or absence of accompanying lower ionization transitions, including measurements of composite profile shapes, equivalent width (EW), characteristic velocities, composite variation profiles, and EW variability. We also measure the correlations between EW and fractional-EW variability for C IV, Si IV, and Al III. Our measurements reveal the basic correlated changes between ionization level, kinematics, and column density expected in accretion-disk wind models; e.g., lines of sight including lower ionization material generally show deeper and broader C IV troughs that have smaller minimum velocities and that are less variable. Many C IV BALs with no accompanying Si IV or Al III BALs may have only mild or no saturation.
9. Partial dust obscuration in active galactic nuclei as a cause of broad-line profile and lag variability, and apparent accretion disc inhomogeneities
Science.gov (United States)
Gaskell, C. Martin; Harrington, Peter Z.
2018-04-01
The profiles of the broad emission lines of active galactic nuclei (AGNs) and the time delays in their response to changes in the ionizing continuum ("lags") give information about the structure and kinematics of the inner regions of AGNs. Line profiles are also our main way of estimating the masses of the supermassive black holes (SMBHs). However, the profiles often show ill-understood, asymmetric structure and velocity-dependent lags vary with time. Here we show that partial obscuration of the broad-line region (BLR) by outflowing, compact, dusty clumps produces asymmetries and velocity-dependent lags similar to those observed. Our model explains previously inexplicable changes in the ratios of the hydrogen lines with time and velocity, the lack of correlation of changes in line profiles with variability of the central engine, the velocity dependence of lags, and the change of lags with time. We propose that changes on timescales longer than the light-crossing time do not come from dynamical changes in the BLR, but are a natural result of the effect of outflowing dusty clumps driven by radiation pressure acting on the dust. The motion of these clumps offers an explanation of long-term changes in polarization. The effects of the dust complicate the study of the structure and kinematics of the BLR and the search for sub-parsec SMBH binaries. Partial obscuration of the accretion disc can also provide the local fluctuations in luminosity that can explain sizes deduced from microlensing.
10. DENSITY WAVE KINEMATICS AND GIANT MOLECULAR ASSOCIATION FORMATION IN M51
NARCIS (Netherlands)
RAND, RJ
1993-01-01
New spectroscopic observations of the ionized gas (Halpha and [N II] lines) in M51 are combined with existing CO, H I, and Halpha data to look for kinematic evidence that the gas is responding to a spiral density wave. Possible mechanisms for the formation of the approximately 3 x 10(7) M. giant
11. Kinematics of SNRs CTB 109 and G206.9+2.3
Science.gov (United States)
Rosado, Margarita; Sánchez-Cruces, Mónica; Ambrocio-Cruz, Patricia
2017-11-01
We present results of optical observations in the lines of Hα and [SII] (λ 6717 and 6731 Å) obtained with the UNAM Scanning Fabry-Perot Interferometer PUMA (Rosado et al. 1995,RMxAASC, 3, 263 ) aimed at obtaining the kinematical distance, shock velocity and other important parameters of two supernova remnants (SNRs) with optical counterparts. We discuss on how kinematical distances thus obtained fit with other distance determinations. The studied SNRs are CTB 109 (SNR G109.1 - 1.0) hosting a magnetar (Sánchez-Cruces et al. 2017, in preparation) and the SNR G206.9 + 2.3 (Ambrocio-Cruz et al. 2014,RMxAA, 50, 323), a typical supernova remnant, to have a comparison. In Fig. 1 is depicted the [SII] line emission of two filaments of the optical counterpart of SNR CTB 109. We find complex radial velocity profiles obtained with the Fabry-Perot interferometer, revealing the presence of different velocity components. From these velocity profiles we obtain the kinematical distance, an expansion velocity of 188 km/s and an initial energy of 8.1 x 1050 ergs. These values are rather typical of other SNRs regardless that SNR CTB 109 hosts a magnetar. Thus, the mechanical energy delivered in the supernova explosion forming the magnetar does not seem to impact more than other SNe explosions the interstellar medium. This work has been funded by grants IN103116 and 253085 from DGAPA-UNAM and CONACYT, respectively.
12. THE STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. I. RECONSTRUCTED VELOCITY-DELAY MAPS
International Nuclear Information System (INIS)
Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C.; Horne, Keith; Bentz, M. C.; Denney, K. D.; Siverd, R.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Bord, D. J.; Che, X.
2013-01-01
We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the Hβ emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II λ4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.
13. THE STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. I. RECONSTRUCTED VELOCITY-DELAY MAPS
Energy Technology Data Exchange (ETDEWEB)
Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Ave, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland (United Kingdom); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Denney, K. D. [Marie Curie Fellow at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Siverd, R. [Department of Physics and Astronomy, Vanderbilt University, 5301 Stevenson Center, Nashville, TN 37235 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); and others
2013-02-10
We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H{beta} emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II {lambda}4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.
14. The role of reversed kinematics and double kinematic solutions in nuclear reactions studies
International Nuclear Information System (INIS)
Kaplan, M.; Parker, W.E.; Moses, D.J.; Lacey, R.; Alexander, J.M.
1993-01-01
The advantages of reversed kinematics in nuclear reactions studies are discussed, with particular emphasis on the origin of double solutions in the reaction kinematics. This possibility for double solutions does not exist in normal kinematics, and provides the basis for a new method of imposing important experimental constraints on the uniqueness of fitting complex observations. By gating on one or the other of the two solutions, light particle kinematics can be greatly influenced in coincidence measurements. The power of the method is illustrated with data for the reaction 1030 MeV 121 Sb+ 27 Al, where charged particle emissions arise from several different sources. (orig.)
15. Regional seismic lines reprocessed using post-stack processing techniques; National Petroleum Reserve, Alaska
Science.gov (United States)
Miller, John J.; Agena, W.F.; Lee, M.W.; Zihlman, F.N.; Grow, J.A.; Taylor, D.J.; Killgore, Michele; Oliver, H.L.
2000-01-01
This CD-ROM contains stacked, migrated, 2-Dimensional seismic reflection data and associated support information for 22 regional seismic lines (3,470 line-miles) recorded in the National Petroleum Reserve ? Alaska (NPRA) from 1974 through 1981. Together, these lines constitute about one-quarter of the seismic data collected as part of the Federal Government?s program to evaluate the petroleum potential of the Reserve. The regional lines, which form a grid covering the entire NPRA, were created by combining various individual lines recorded in different years using different recording parameters. These data were reprocessed by the USGS using modern, post-stack processing techniques, to create a data set suitable for interpretation on interactive seismic interpretation computer workstations. Reprocessing was done in support of ongoing petroleum resource studies by the USGS Energy Program. The CD-ROM contains the following files: 1) 22 files containing the digital seismic data in standard, SEG-Y format; 2) 1 file containing navigation data for the 22 lines in standard SEG-P1 format; 3) 22 small scale graphic images of each seismic line in Adobe Acrobat? PDF format; 4) a graphic image of the location map, generated from the navigation file, with hyperlinks to the graphic images of the seismic lines; 5) an ASCII text file with cross-reference information for relating the sequential trace numbers on each regional line to the line number and shotpoint number of the original component lines; and 6) an explanation of the processing used to create the final seismic sections (this document). The SEG-Y format seismic files and SEG-P1 format navigation file contain all the information necessary for loading the data onto a seismic interpretation workstation.
16. Application of robot kinematics methods to the simulation and control of neutron beam line positioning systems
Energy Technology Data Exchange (ETDEWEB)
James, Jonathan A. [Open University, Materials Engineering, Walton Hall, Milton Keynes, Buckinghamshire MK7 6AA (United Kingdom)]. E-mail: j.a.j.james@open.ac.uk; Edwards, Lyndon [Open University, Materials Engineering, Walton Hall, Milton Keynes, Buckinghamshire MK7 6AA (United Kingdom)
2007-02-11
Neutron stress measurements require specimens of complex geometry to be speedily and accurately positioned and oriented with respect to the neutron beam. Recognition that a majority of the specimen positioning systems in use at strain scanning facilities are effectively serial robot manipulators, suggests that the methods of serial robot kinematic modelling may be applied to advantage. The adoption of robotics methods provides a simple and reliable framework for controlling positioning systems of arbitrary geometry and complexity. In addition the numerical solution of the inverse kinematic problem is facilitated, allowing specimens to be automatically positioned and orientated so that pre-determined strain components are measured. It is also shown that, given sufficient degrees of freedom, a secondary characteristic of the measurement position such as the measurement count time may be simultaneously optimised.
17. X-ray heating and ionization of broad-emission-line regions in QSO's and active galaxies
International Nuclear Information System (INIS)
Weisheit, J.C.; Shields, G.A.; Tarter, C.B.
1980-07-01
Absorption of x-rays deep within the broad-line emitting clouds in QSO's and the nuclei of active galaxies creates extensive zones of warm (T approx. 10 4 K), partially ionized N/sub e//N approx. 0.1) gas. Because Lyman alpha photons are trapped in these regions, the x-ray energy is efficiently channeled into Balmer lines collisionally excited from the n = 2 level. The HI regions plus the HII regions created by ultraviolet photons illuminating the surfaces of the clouds give rise to integrated Lα/Hα line emission ratios between 1 and 2. Enhanced MgII line emission from the HI regions gives rise to integrated MgII/Hα ratios near 0.5. The OI line lambda 8446 is efficiently pumped by trapped Hα photons and in the x-ray heated zone an intensity ratio I (lambda 8446)/I(Hα) approx. < 0.1 is calculated. All of these computed ratios now are in agreement with observations
18. Variation of nuclear radii in the drip line regions
CERN Document Server
Beiner, M; Mas, D
1976-01-01
The authors are concerned with predictions of the energy density method with respect to the nuclear sizes (RMS radii). It is known that the commonly accepted A/sup 1/3/-type laws are only approximative and deviations are expected to grow significantly as one goes away from the beta -stability region. Particular attention is paid to the variation of nuclear radii in the drip line regions. Implications of the resulting large total Coulomb energy variations between neighbouring nuclei will be emphasized.
19. THE BOLOCAM GALACTIC PLANE SURVEY. XII. DISTANCE CATALOG EXPANSION USING KINEMATIC ISOLATION OF DENSE MOLECULAR CLOUD STRUCTURES WITH {sup 13}CO(1-0)
Energy Technology Data Exchange (ETDEWEB)
Ellsworth-Bowers, Timothy P.; Glenn, Jason [CASA, University of Colorado, UCB 389, Boulder, CO 80309 (United States); Rosolowsky, Erik [Department of Physics, 4-183 CCIS, University of Alberta, Edmonton, AB T6G 2E1 (Canada); Ginsburg, Adam [European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748 Garching bei München (Germany); Evans II, Neal J. [Department of Astronomy, University of Texas, 2515 Speedway, Stop C1400, Austin, TX 78712 (United States); Battersby, Cara [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Shirley, Yancy L.; Svoboda, Brian, E-mail: timothy.ellsworthbowers@colorado.edu [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
2015-01-20
We present an expanded distance catalog for 1710 molecular cloud structures identified in the Bolocam Galactic Plane Survey (BGPS) version 2, representing a nearly threefold increase over the previous BGPS distance catalog. We additionally present a new method for incorporating extant data sets into our Bayesian distance probability density function (DPDF) methodology. To augment the dense-gas tracers (e.g., HCO{sup +}(3-2), NH{sub 3}(1,1)) used to derive line-of-sight velocities for kinematic distances, we utilize the Galactic Ring Survey (GRS) {sup 13}CO(1-0) data to morphologically extract velocities for BGPS sources. The outline of a BGPS source is used to select a region of the GRS {sup 13}CO data, along with a reference region to subtract enveloping diffuse emission, to produce a line profile of {sup 13}CO matched to the BGPS source. For objects with a HCO{sup +}(3-2) velocity, ≈95% of the new {sup 13}CO(1-0) velocities agree with that of the dense gas. A new prior DPDF for kinematic distance ambiguity (KDA) resolution, based on a validated formalism for associating molecular cloud structures with known objects from the literature, is presented. We demonstrate this prior using catalogs of masers with trigonometric parallaxes and H II regions with robust KDA resolutions. The distance catalog presented here contains well-constrained distance estimates for 20% of BGPS V2 sources, with typical distance uncertainties ≲ 0.5 kpc. Approximately 75% of the well-constrained sources lie within 6 kpc of the Sun, concentrated in the Scutum-Centaurus arm. Galactocentric positions of objects additionally trace out portions of the Sagittarius, Perseus, and Outer arms in the first and second Galactic quadrants, and we also find evidence for significant regions of interarm dense gas.
20. Primate Anatomy, Kinematics, and Principles for Humanoid Design
Science.gov (United States)
Ambrose, Robert O.; Ambrose, Catherine G.
2004-01-01
The primate order of animals is investigated for clues in the design of Humanoid Robots. The pursuit is directed with a theory that kinematics, musculature, perception, and cognition can be optimized for specific tasks by varying the proportions of limbs, and in particular, the points of branching in kinematic trees such as the primate skeleton. Called the Bifurcated Chain Hypothesis, the theory is that the branching proportions found in humans may be superior to other animals and primates for the tasks of dexterous manipulation and other human specialties. The primate taxa are defined, contemporary primate evolution hypotheses are critiqued, and variations within the order are noted. The kinematic branching points of the torso, limbs and fingers are studied for differences in proportions across the order, and associated with family and genus capabilities and behaviors. The human configuration of a long waist, long neck, and short arms is graded using a kinematic workspace analysis and a set of design axioms for mobile manipulation robots. It scores well. The re emergence of the human waist, seen in early Prosimians and Monkeys for arboreal balance, but lost in the terrestrial Pongidae, is postulated as benefiting human dexterity. The human combination of an articulated waist and neck will be shown to enable the use of smaller arms, achieving greater regions of workspace dexterity than the larger limbs of Gorillas and other Hominoidea.
1. Distribution and kinematics of atomic and molecular gas inside the solar circle
Science.gov (United States)
Marasco, A.; Fraternali, F.; van der Hulst, J. M.; Oosterloo, T.
2017-11-01
The detailed distribution and kinematics of the atomic and the CO-bright molecular hydrogen in the disc of the Milky Way inside the solar circle are derived under the assumptions of axisymmetry and pure circular motions. We divide the Galactic disc into a series of rings, and assume that the gas in each ring is described by four parameters: its rotation velocity, velocity dispersion, midplane density and its scale height. We fit these parameters to the Galactic H I and 12CO (J = 1-0) data by producing artificial H I and CO line-profiles and comparing them with the observations. Our approach allows us to fit all parameters to the data simultaneously without assuming a-priori a radial profile for one of the parameters. We present the distribution and kinematics of the H I and H2 in both the approaching (QIV) and the receding (QI) regions of the Galaxy. Our best-fit models reproduces remarkably well the observed H I and CO longitude-velocity diagrams up to a few degrees of distance from the midplane. With the exception of the innermost 2.5 kpc, QI and QIV show very similar kinematics. The rotation curves traced by the H I and H2 follow each other closely, flattening beyond R = 6.5 kpc. Both the H I and the H2 surface densities show a) a deep depression at 0.5 < R < 2.5 kpc, analogous to that shown by some nearby barred galaxies, b) local overdensities that can be interpreted in terms of spiral arms or ring-like features in the disc. The H I (H2) properties are fairly constant in the region outside the depression, with typical velocity dispersion of 8.9 ± 1.1 (4.4 ± 1.2) km s-1, density of 0.43 ± 0.11 (0.42 ± 0.22) cm-3 and HWHM scale height of 202 ± 28 (64 ± 12) pc. We also show that the H I opacity in the LAB data can be accounted for by using an "effective" spin temperature of 150 K: assuming an optically thin regime leads to an underestimate of the H I mass by about 30%.
2. Gas Content and Kinematics in Clumpy, Turbulent Star-forming Disks
International Nuclear Information System (INIS)
White, Heidi A.; Abraham, Roberto G.; Fisher, David B.; Glazebrook, Karl; Murray, Norman; Bolatto, Alberto D.; Green, Andrew W.; Mentuch Cooper, Erin; Obreschkow, Danail
2017-01-01
We present molecular gas-mass estimates for a sample of 13 local galaxies whose kinematic and star-forming properties closely resemble those observed in z ≈ 1.5 main-sequence galaxies. Plateau de Bure observations of the CO[1-0] emission line and Herschel Space Observatory observations of the dust emission both suggest molecular gas-mass fractions of ∼20%. Moreover, dust emission modeling finds T dust < 30 K, suggesting a cold dust distribution compared to their high infrared luminosity. The gas-mass estimates argue that z ∼ 0.1 DYNAMO galaxies not only share similar kinematic properties with high- z disks, but they are also similarly rich in molecular material. Pairing the gas-mass fractions with existing kinematics reveals a linear relationship between f gas and σ / v c , consistent with predictions from stability theory of a self-gravitating disk. It thus follows that high gas-velocity dispersions are a natural consequence of large gas fractions. We also find that the systems with the lowest t dep (∼0.5 Gyr) have the highest ratios of σ / v c and more pronounced clumps, even at the same high molecular gas fraction.
3. Gas Content and Kinematics in Clumpy, Turbulent Star-forming Disks
Energy Technology Data Exchange (ETDEWEB)
White, Heidi A.; Abraham, Roberto G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H8 (Canada); Fisher, David B.; Glazebrook, Karl [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia); Murray, Norman [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto ON M5S 3H8 (Canada); Bolatto, Alberto D. [Department of Astronomy and Joint Space Institute, University of Maryland, College Park, MD 20642 (United States); Green, Andrew W. [Australian Astronomical Observatory, P.O. Box 970, North Ryde, NSW 1670 (Australia); Mentuch Cooper, Erin [Astronomy Department, University of Texas at Austin, Austin, TX 78712 (United States); Obreschkow, Danail [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, M468, Crawley, WA 6009 (Australia)
2017-09-01
We present molecular gas-mass estimates for a sample of 13 local galaxies whose kinematic and star-forming properties closely resemble those observed in z ≈ 1.5 main-sequence galaxies. Plateau de Bure observations of the CO[1-0] emission line and Herschel Space Observatory observations of the dust emission both suggest molecular gas-mass fractions of ∼20%. Moreover, dust emission modeling finds T {sub dust} < 30 K, suggesting a cold dust distribution compared to their high infrared luminosity. The gas-mass estimates argue that z ∼ 0.1 DYNAMO galaxies not only share similar kinematic properties with high- z disks, but they are also similarly rich in molecular material. Pairing the gas-mass fractions with existing kinematics reveals a linear relationship between f {sub gas} and σ / v {sub c}, consistent with predictions from stability theory of a self-gravitating disk. It thus follows that high gas-velocity dispersions are a natural consequence of large gas fractions. We also find that the systems with the lowest t {sub dep} (∼0.5 Gyr) have the highest ratios of σ / v{sub c} and more pronounced clumps, even at the same high molecular gas fraction.
4. Movement coordination and differential kinematics of the cervical and thoracic spines in people with chronic neck pain.
Science.gov (United States)
Tsang, Sharon M H; Szeto, Grace P Y; Lee, Raymond Y W
2013-07-01
Research on the kinematics and inter-regional coordination of movements between the cervical and thoracic spines in motion adds to our understanding of the performance and interplay of these spinal regions. The purpose of this study was to examine the effects of chronic neck pain on the three-dimensional kinematics and coordination of the cervical and thoracic spines during active movements of the neck. Three-dimensional spinal kinematics and movement coordination between the cervical, upper thoracic, and lower thoracic spines were examined by electromagnetic motion sensors in thirty-four individuals with chronic neck pain and thirty-four age- and gender-matched asymptomatic subjects. All subjects performed a set of free active neck movements in three anatomical planes in sitting position and at their own pace. Spinal kinematic variables (angular displacement, velocity, and acceleration) of the three defined regions, and movement coordination between regions were determined and compared between the two groups. Subjects with chronic neck pain exhibited significantly decreased cervical angular velocity and acceleration of neck movement. Cross-correlation analysis revealed consistently lower degrees of coordination between the cervical and upper thoracic spines in the neck pain group. The loss of coordination was most apparent in angular velocity and acceleration of the spine. Assessment of the range of motion of the neck is not sufficient to reveal movement dysfunctions in chronic neck pain subjects. Evaluation of angular velocity and acceleration and movement coordination should be included to help develop clinical intervention strategies to promote restoration of differential kinematics and movement coordination. Copyright © 2013 Elsevier Ltd. All rights reserved.
5. Nuclear reaction studies using inverse kinematics
International Nuclear Information System (INIS)
Shapira, D.
1985-01-01
Reaction studies with reversed kinematics refer to studies of nuclear reactions induced by a heavy projectile colliding with lighter target nuclei. The technique of using reversed kinematics is costly in terms of the available center-of-mass energy. Most of the projectile's energy goes into forward motion of the reaction products in the laboratory system. Examples are presented where the use of reversed kinematics techniques has provided new information on certain reaction processes. A list of kinematic properties and advantages they may afford is shown. Clearly the possible studies listed can be done without using reversed kinematics but because of the difficulty associated with some of these studies they were never performed until more energetic heavier beams have become available and the reversed kinematics technique was utilized
6. Line formation in the solar chromosphere. II - An optically thick region of the chromosphere-corona transition region observed with OSO 8
Science.gov (United States)
Lites, B. W.; Hansen, E. R.; Shine, R. A.
1980-01-01
The University of Colorado ultraviolet spectrometer aboard the Orbiting Solar Observatory 8(OSO 8) has measured self-reversed profiles of the resonance line of C IV lamda 1548.2 at the limb passage of an active region. The degree of the self-reversal together with the absolute intensity of the line profile determine the electron density in the active region at 10 to the 10th/cu cm at temperatures where the C IV line is formed. The nonthermal component of the broadening velocity is no more than 14km/s, and the physical thickness of an equivalent plane-parallel slab in hydrostatic equilibrium that would give rise to the observed line profiles is about 430 km.
7. Kinematics of the CSE in VY CMa
Science.gov (United States)
Choi, Yoon Kyung
2009-07-01
We report on astrometric results of H2O and SiO masers in the circumstellar envelopes of VY Canis Majoris (VY CMa) carried out with VERA for 2 years. Absolute positions and proper motions of 3 different frequencies of masers were measured with phase-referencing analyses. Using the positions and the 3-dimensional velocities of the masers, we considered the 3-dimensional structures and kinematics of the circumstellar envelopes around VY CMa. The H2O masers show bipolar outflow along the line of sight, and the SiO masers have both expanding and contracting motions with less than 5 km/s.
8. Kinematic Model of NAO Humanoid Robot
Directory of Open Access Journals (Sweden)
Miloš D. Jovanović
2014-06-01
Full Text Available This paper presents synthesis of kinematic model of NAO humanoid robot of Aldebaran Robotics. NAO humanoid robot has complex kinematic structure with 25 active degrees of freedom (DOF. Humanoid system is formed through 5 mutually depended kinematic chains. After that we applied standard aspects of kinematic chains synthesis and Denavit-Hartenberg parameters of each of 5 chains of robotic structure were introduced. Also, mutual relationships between chains were described, as well as their physical and structural dependence. Generated kinematic model will be the starting point for further dynamical modeling of NAO humanoid robot and motion synthesis on actual platform.
9. The Ca II resonance lines in M dwarf stars without H-alpha emission
Energy Technology Data Exchange (ETDEWEB)
Giampapa, M.S.; Cram, L.E.; Wild, W.J. (National Solar Observatory, Tucson, AZ (USA) Sydney Univ. (Australia) Arizona Univ., Tucson (USA))
1989-10-01
Spectra of the Ca II H and K lines in a sample of 31 M dwarf stars without H-alpha emission are used to calculate chromospheric K line radiative losses, F(k), and to study the joint response of Ca II K and H-alpha to chromospheric heating in dwarf M stars. It is suggested that the poor correlation found in the equivalent width - log F(K) diagram may be due either to radial segregation of the H-alpha and K line forming regions or to lateral inhomogeneities in the chromospheres. The results confirm the existence of dM stars with weak H-alpha absorption and K line emission only slightly weaker than that of the dMe stars, and show that dM stars with weak H-alpha but kinematics and metallicities representative of the young disk population belong to a class characterized by a comparatively high degree of chromospheric activity. 32 refs.
10. Kinematical Comparison of the 200 m Backstroke Turns between National and Regional Level Swimmers
Science.gov (United States)
Veiga, Santiago; Cala, Antonio; Frutos, Pablo González; Navarro, Enrique
2013-01-01
The aims of this investigation were to determine the evolution of selected turn variables during competitive backstroke races and to compare these kinematic variables between two different levels of swimmers. Sixteen national and regional level male swimmers participant in the 200 m backstroke event at the Spanish Swimming Championships in short course (25 m) were selected to analyze their turn performances. The individual distances method with two-dimensional Direct Linear Transformation (2D-DLT) algorithms was used to perform race analyses. National level swimmers presented a shorter “turn time”, a longer “distance in”, a faster “underwater velocity” and “normalized underwater velocity”, and a faster “stroking velocity” than regional level swimmers, whereas no significant differences were detected between levels for the “underwater distance”. National level swimmers maintained similar “turn times” over the event and increased “underwater velocity” and “normalized underwater velocity” in the last (seventh) turn segment, whereas regional level swimmers increased “turn time” in the last half of the race. For both national and regional level swimmers, turn “underwater distance” during the last three turns of the race was significantly shorter while no significant differences in distance into the wall occurred throughout the race. The skill level of the swimmers has an impact on the competitive backstroke turn segments. In a 200 m event, the underwater velocity should be maximized to maintain turn proficiency, whereas turn distance must be subordinated to the average velocity. Key Points The underwater turn velocity is as a critical variable related to the swimmers’ level of skill in a 200 m backstroke event. Best swimmers perform faster but no longer turn segments during a 200 m backstroke event. Best swimmers maintain their turn performance throughout the 200 m backstroke event by increasing the underwater velocity
11. Emission-line diagnostics of nearby H II regions including interacting binary populations
Science.gov (United States)
Xiao, Lin; Stanway, Elizabeth R.; Eldridge, J. J.
2018-06-01
We present numerical models of the nebular emission from H II regions around young stellar populations over a range of compositions and ages. The synthetic stellar populations include both single stars and interacting binary stars. We compare these models to the observed emission lines of 254 H II regions of 13 nearby spiral galaxies and 21 dwarf galaxies drawn from archival data. The models are created using the combination of the BPASS (Binary Population and Spectral Synthesis) code with the photoionization code CLOUDY to study the differences caused by the inclusion of interacting binary stars in the stellar population. We obtain agreement with the observed emission line ratios from the nearby star-forming regions and discuss the effect of binary-star evolution pathways on the nebular ionization of H II regions. We find that at population ages above 10 Myr, single-star models rapidly decrease in flux and ionization strength, while binary-star models still produce strong flux and high [O III]/H β ratios. Our models can reproduce the metallicity of H II regions from spiral galaxies, but we find higher metallicities than previously estimated for the H II regions from dwarf galaxies. Comparing the equivalent width of H β emission between models and observations, we find that accounting for ionizing photon leakage can affect age estimates for H II regions. When it is included, the typical age derived for H II regions is 5 Myr from single-star models, and up to 10 Myr with binary-star models. This is due to the existence of binary-star evolution pathways, which produce more hot Wolf-Rayet and helium stars at older ages. For future reference, we calculate new BPASS binary maximal starburst lines as a function of metallicity, and for the total model population, and present these in Appendix A.
12. Synthesis method based on solution regions for planar four bar straight line linkages
International Nuclear Information System (INIS)
Lai Rong, Yin; Cong, Mao; Jian you, Han; Tong, Yang; Juan, Huang
2012-01-01
An analytical method for synthesizing and selecting desired four-bar straight line mechanisms based on solution regions is presented. Given two fixed pivots, the point position and direction of the target straight line, an infinite number of mechanism solutions can be produced by employing this method, both in the general case and all three special cases. Unifying the straight line direction and the displacement from the given point to the instant center into the same form with different angles as parameters, infinite mechanism solutions can be expressed with different solution region charts. The mechanism property graphs have been computed to enable the designers to find out the involved mechanism information more intuitively and avoid aimlessness in selecting optimal mechanisms
13. Correlates between kinematics and baropodometric measurements for an integrated in-vivo assessment of the segmental foot function in gait.
Science.gov (United States)
Giacomozzi, Claudia; Leardini, Alberto; Caravaggi, Paolo
2014-08-22
14. Gene mutation in ATM/PI3K region of nasopharyngeal carcinoma cell lines
International Nuclear Information System (INIS)
Wang Hongmei; Wu Xinyao; Xia Yunfei
2002-01-01
Objective: To define the correlation between nasopharyngeal carcinoma (NPC) cell radiosensitivity and gene mutation in the ATM/PI3K coding region. Methods: The gene mutation in the ATM/PI3K region of nasopharyngeal carcinoma cell lines which vary in radiosensitivity, was monitored by reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence-marked ddNTP cycle sequencing technique. Results: No gene mutation was detected in the ATM/PI3K region of either CNE1 or CNE2. Conclusion: Disparity in intrinsic radiosensitivity between different NPC cell lines depends on some other factors and mechanism without being related to ATM/PI3K mutations
15. THE DiskMass SURVEY. III. STELLAR KINEMATICS VIA CROSS-CORRELATION
International Nuclear Information System (INIS)
Westfall, Kyle B.; Bershady, Matthew A.; Verheijen, Marc A. W.
2011-01-01
We describe a new cross-correlation (CC) approach used by our survey to derive stellar kinematics from galaxy-continuum spectroscopy. This approach adopts the formal error analysis derived by Statler, but properly handles spectral masks. Thus, we address the primary concerns regarding application of the CC method to censored data, while maintaining its primary advantage by consolidating kinematic and template-mismatch information toward different regions of the CC function. We identify a systematic error in the nominal CC method of approximately 10% in velocity dispersion incurred by a mistreatment of detector-censored data, which is eliminated by our new method. We derive our approach from first principles, and we use Monte Carlo simulations to demonstrate its efficacy. An identical set of Monte Carlo simulations performed using the well-established penalized-pixel-fitting code of Cappellari and Emsellem compares favorably with the results from our newly implemented software. Finally, we provide a practical demonstration of this software by extracting stellar kinematics from SparsePak spectra of UGC 6918.
16. Diffusion effects on the line intensities of He I and He II in the solar transition region
International Nuclear Information System (INIS)
Shine, R.; Gerola, H.; Linsky, J.L.
1975-01-01
A heuristic treatment of diffusion in the solar chromosphere-corona transition region is developed. Diffusion becomes increasingly important with steeper temperature gradients, in active and quiet regions relative to coronal holes, and with increasing excitation potential. Numerical calculations are made for the resonance lines of He i and He ii and show that diffusion can enhance these lines. Thus the helium lines may appear relatively weak in coronal holes due to a weakening of the enhancement mechanism. Most transition region lines will be less affected by diffusion than He i or He ii
17. Electron density in the emission-line region of Wolf-Rayet stars
International Nuclear Information System (INIS)
Varshni, Y.P.
1978-01-01
The Inglis-Teller relation, generalized for a hydrogen-like or alkali-like ion with an arbitrary core charge, is used to estimate the electron density in the emission-like region of Wolf-Rayet stars. It is found that the electron density in the region which gives rise to He II emission lines is approximately = 4 x 10 14 cm -3 . (Auth.)
18. KINEMATICS OF EXTREMELY METAL-POOR GALAXIES: EVIDENCE FOR STELLAR FEEDBACK
Energy Technology Data Exchange (ETDEWEB)
Olmo-García, A.; Sánchez Almeida, J.; Muñoz-Tuñón, C.; Filho, M. E. [Instituto Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Elmegreen, B. G. [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, NY 10598 (United States); Elmegreen, D. M. [Department of Physics and Astronomy, Vassar College, Poughkeepsie, NY 12604 (United States); Pérez-Montero, E. [Instituto de Astrofísica de Andalucía, CSIC, Granada (Spain); Méndez-Abreu, J., E-mail: jos@iac.es [School of Physics and Astronomy, University of St Andrews, St Andrews (United Kingdom)
2017-01-10
The extremely metal-poor (XMP) galaxies analyzed in a previous paper have large star-forming regions with a metallicity lower than the rest of the galaxy. Such a chemical inhomogeneity reveals the external origin of the metal-poor gas fueling star formation, possibly indicating accretion from the cosmic web. This paper studies the kinematic properties of the ionized gas in these galaxies. Most XMPs have a rotation velocity around a few tens of km s{sup −1}. The star-forming regions appear to move coherently. The velocity is constant within each region, and the velocity dispersion sometimes increases within the star-forming clump toward the galaxy midpoint, suggesting inspiral motion toward the galaxy center. Other regions present a local maximum in velocity dispersion at their center, suggesting a moderate global expansion. The H α line wings show a number of faint emission features with amplitudes around a few per cent of the main H α component, and wavelength shifts between 100 and 400 km s{sup −1}. The components are often paired, so that red and blue emission features with similar amplitudes and shifts appear simultaneously. Assuming the faint emission to be produced by expanding shell-like structures, the inferred mass loading factor (mass loss rate divided by star formation rate) exceeds 10. Since the expansion velocity far exceeds the rotational and turbulent velocities, the gas may eventually escape from the galaxy disk. The observed motions involve energies consistent with the kinetic energy released by individual core-collapse supernovae. Alternative explanations for the faint emission have been considered and discarded.
19. Modelling the gas kinematics of an atypical Ly α emitting compact dwarf galaxy
Science.gov (United States)
Forero-Romero, Jaime E.; Gronke, Max; Remolina-Gutiérrez, Maria Camila; Garavito-Camargo, Nicolás; Dijkstra, Mark
2018-02-01
Star-forming compact dwarf galaxies (CDGs) resemble the expected pristine conditions of the first galaxies in the Universe and are the best systems to test models on primordial galaxy formation and evolution. Here, we report on one of such CDGs, Tololo 1214-277, which presents a broad, single peaked, highly symmetric Ly α emission line that had evaded theoretical interpretation so far. In this paper, we reproduce for the first time these line features with two different physically motivated kinematic models: an interstellar medium composed by outflowing clumps with random motions and an homogeneous gaseous sphere undergoing solid body rotation. The multiphase model requires a clump velocity dispersion of 54.3 ± 0.6 km s-1 with outflows of 54.3 ± 5.1 km s-1 , while the bulk rotation velocity is constrained to be 348^{+75}_{-48} km s-1. We argue that the results from the multiphase model provide a correct interpretation of the data. In that case, the clump velocity dispersion implies a dynamical mass of 2 × 109 M⊙, 10 times its baryonic mass. If future kinematic maps of Tololo 1214-277 confirm the velocities suggested by the multiphase model, it would provide additional support to expect such kinematic state in primordial galaxies, opening the opportunity to use the models and methods presented in this paper to constrain the physics of star formation and feedback in the early generation of Ly α -emitting galaxies.
20. Inverse Kinematics using Quaternions
DEFF Research Database (Denmark)
Henriksen, Knud; Erleben, Kenny; Engell-Nørregård, Morten
In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection....
1. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability
International Nuclear Information System (INIS)
Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S.; Bentz, M. C.; Vestergaard, M.; Kilerci-Eser, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Dalla Bontà, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Ciroi, S.
2013-01-01
The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n e ∼ 10 5 cm –3 ) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.
2. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability
Energy Technology Data Exchange (ETDEWEB)
Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 610, Atlanta, GA 30303 (United States); Vestergaard, M.; Kilerci-Eser, E. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Dalla Bontà, E.; Ciroi, S. [Dipartimento di Fisica e Astronomia " G. Galilei," Università di Padova, Vicolo dell' Osservatorio 3 I-35122, Padova (Italy)
2013-12-20
The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n {sub e} ∼ 10{sup 5} cm{sup –3}) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.
3. Why is observable radio recombination line emission from galactic HII regions always close to LTE
International Nuclear Information System (INIS)
Shaver, P.A.
1980-01-01
There is no evidence for significant deviations from LTE in single-dish observations of radio recombination line emission from galactic HII regions. This is in agreement with the known properties of HII regions, particularly their density variations and limited range of excitation parameters; the optimum configuration for strong observable non-LTE effects, low electron density and high emission measure, simply does not exist in galactic HII regions, and the observed lines are emitted under near-LTE conditions. Models of the Orion Nebulae and NGC 6604 are presented which fit all available data and show only weak stimulated emission. It is concluded that reliable electron temperatures can indeed be obtained from straightforward analysis of appropriate radio recombination lines. (orig.)
4. BUBBLES AND KNOTS IN THE KINEMATICAL STRUCTURE OF THE BIPOLAR PLANETARY NEBULA NGC 2818
Energy Technology Data Exchange (ETDEWEB)
Vazquez, Roberto, E-mail: vazquez@astro.unam.mx [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, BC (Mexico)
2012-06-01
High-resolution Hubble Space Telescope archive imaging and high-dispersion spectroscopy are used to study the complex morphological and kinematical structure of the planetary nebula, NGC 2818. We analyze narrowband H{alpha}, [O III], [N II], [S II], and He II images, addressing important morphological features. Ground-based long-slit echelle spectra were obtained crossing NGC 2818 at five different positions to precisely determine kinematical features in the structure of the nebula. A distance of 2.5 kpc was used to determine physical scales. Constructing models to fit the data with modern computational tools, we find NGC 2818 is composed of (1) a non-uniform bipolar structure with a semimajor axis of 0.92 pc (75''), possibly deformed by the stellar wind, (2) a 0.17 pc (14'') diameter central region, which is potentially the remnant of an equatorial enhancement, and (3) a great number of cometary knots. These knots are preferentially located inside a radius of 0.24 pc (20'') around the central star. The major axis of the main structure is oriented at i {approx_equal} 60 Degree-Sign with respect to the line of sight and at P.A. = +89 Degree-Sign on the plane of the sky. Expansion velocities of this nebula are V{sub pol} = 105 km s{sup -1} and V{sub eq} = 20 km s{sup -1}, which lead to our estimate of the kinematical age of {tau}{sub k} {approx_equal} 8400 {+-} 3400 yr (assuming homologous expansion). Our observations do not support the idea that high-velocity collimated ejections are responsible for the formation of microstructures inside the nebula. We determine the systemic velocity of NGC 2818 to be V{sub HEL} = +26 {+-} 2 km s{sup -1}.
5. Advances in robot kinematics
CERN Document Server
Khatib, Oussama
2014-01-01
The topics addressed in this book cover the whole range of kinematic analysis, synthesis and design and consider robotic systems possessing serial, parallel and cable driven mechanisms. The robotic systems range from being less than fully mobile to kinematically redundant to overconstrained. The fifty-six contributions report the latest results in robot kinematics with emphasis on emerging areas such as design and control of humanoids or humanoid subsystems. The book is of interest to researchers wanting to bring their knowledge up to date regarding modern topics in one of the basic disciplines in robotics, which relates to the essential property of robots, the motion of mechanisms.
6. The 2 mrad crossing-angle ILC interaction region and extraction line
CERN Document Server
Appleby, Robert; Bambade, Philip; Dadoun, Olivier; Parker, Brett; Keller, Lewis; Moffeit, Kenneth C; Nosochkov, Yuri; Seryi, Andrei; Spencer, Cherrill M; Carter, John; Napoly, Olivier
2006-01-01
A complete optics design for the 2mrad crossing angle interaction region and extraction line was presented at Snowmass 2005. Since this time, the design task force has been working on developing and improving the performance of the extraction line. The work has focused on optimising the final doublet parameters and on reducing the power losses resulting from the disrupted beam transport. In this paper, the most recent status of the 2mrad layout and the corresponding performance are presented.
7. Conceptual design and kinematic analysis of a novel parallel robot for high-speed pick-and-place operations
Science.gov (United States)
Meng, Qizhi; Xie, Fugui; Liu, Xin-Jun
2018-06-01
This paper deals with the conceptual design, kinematic analysis and workspace identification of a novel four degrees-of-freedom (DOFs) high-speed spatial parallel robot for pick-and-place operations. The proposed spatial parallel robot consists of a base, four arms and a 1½ mobile platform. The mobile platform is a major innovation that avoids output singularity and offers the advantages of both single and double platforms. To investigate the characteristics of the robot's DOFs, a line graph method based on Grassmann line geometry is adopted in mobility analysis. In addition, the inverse kinematics is derived, and the constraint conditions to identify the correct solution are also provided. On the basis of the proposed concept, the workspace of the robot is identified using a set of presupposed parameters by taking input and output transmission index as the performance evaluation criteria.
8. Identification of new solar OH lines in the 10--12 micron region
International Nuclear Information System (INIS)
Goldman, A.; Murcray, F.J.; Gillis, J.R.; Murcray, D.G.
1981-01-01
High-resolution (0.02 cm -1 ) infrared solar spectra obtained with a balloon-borne interferometer reveal new solar absorption features, which appear as regularly spaced quartets, in the 825--960 cm -1 region. The lines are interpreted as high N'' (25--33) pure rotation lines of solar OH. An effective amount of approx.8 x 10 15 molecules cm -2 of OH is estimated from the spectra
9. Kinematic parameters of signed verbs.
Science.gov (United States)
Malaia, Evie; Wilbur, Ronnie B; Milkovic, Marina
2013-10-01
Sign language users recruit physical properties of visual motion to convey linguistic information. Research on American Sign Language (ASL) indicates that signers systematically use kinematic features (e.g., velocity, deceleration) of dominant hand motion for distinguishing specific semantic properties of verb classes in production ( Malaia & Wilbur, 2012a) and process these distinctions as part of the phonological structure of these verb classes in comprehension ( Malaia, Ranaweera, Wilbur, & Talavage, 2012). These studies are driven by the event visibility hypothesis by Wilbur (2003), who proposed that such use of kinematic features should be universal to sign language (SL) by the grammaticalization of physics and geometry for linguistic purposes. In a prior motion capture study, Malaia and Wilbur (2012a) lent support for the event visibility hypothesis in ASL, but there has not been quantitative data from other SLs to test the generalization to other languages. The authors investigated the kinematic parameters of predicates in Croatian Sign Language ( Hrvatskom Znakovnom Jeziku [HZJ]). Kinematic features of verb signs were affected both by event structure of the predicate (semantics) and phrase position within the sentence (prosody). The data demonstrate that kinematic features of motion in HZJ verb signs are recruited to convey morphological and prosodic information. This is the first crosslinguistic motion capture confirmation that specific kinematic properties of articulator motion are grammaticalized in other SLs to express linguistic features.
10. Kinematics Control and Analysis of Industrial Robot
Science.gov (United States)
Zhu, Tongbo; Cai, Fan; Li, Yongmei; Liu, Wei
2018-03-01
The robot’s development present situation, basic principle and control system are introduced briefly. Research is mainly focused on the study of the robot’s kinematics and motion control. The structural analysis of a planar articulated robot (SCARA) robot is presented,the coordinate system is established to obtain the position and orientation matrix of the end effector,a method of robot kinematics analysis based on homogeneous transformation method is proposed, and the kinematics solution of the robot is obtained.Establishment of industrial robot’s kinematics equation and formula for positive kinematics by example. Finally,the kinematic analysis of this robot was verified by examples.It provides a basis for structural design and motion control.It has active significance to promote the motion control of industrial robot.
11. Time variations of oxygen emission lines and solar wind dynamic parameters in low latitude region
Science.gov (United States)
Jamlongkul, P.; Wannawichian, S.; Mkrtichian, D.; Sawangwit, U.; A-thano, N.
2017-09-01
Aurora phenomenon is an effect of collision between precipitating particles with gyromotion along Earth’s magnetic field and Earth’s ionospheric atoms or molecules. The particles’ precipitation occurs normally around polar regions. However, some auroral particles can reach lower latitude regions when they are highly energetic. A clear emission from Earth’s aurora is mostly from atomic oxygen. Moreover, the sun’s activities can influence the occurrence of the aurora as well. This work studies time variations of oxygen emission lines and solar wind parameters, simultaneously. The emission’s spectral lines were observed by Medium Resolution Echelle Spectrograph (MRES) along with 2.4 meters diameter telescope at Thai National Observatory, Intanon Mountain, Chiang Mai, Thailand. Oxygen (OI) emission lines were calibrated by Dech-Fits spectra processing program and Dech95 2D image processing program. The correlations between oxygen emission lines and solar wind dynamics will be analyzed. This result could be an evidence of the aurora in low latitude region.
12. The ESO Nearby Abell Cluster Survey. VI. Spatial distribution and kinematics of early- and late-type galaxies
Science.gov (United States)
de Theije, P. A. M.; Katgert, P.
1999-01-01
Analysis of the data obtained in the ESO Nearby Abell Cluster Survey (ENACS) has shown that the space distribution and kinematics of galaxies with detectable emission lines in their spectra differ significantly from those of galaxies without emission lines. This result, and details of the kinematics, were considered as support for the idea that at least the spirals with emission lines are on orbits that are not isotropic. This might indicate that this subset of late-type galaxies either has first approach'-orbits towards the dense core of their respective clusters, or has orbits that avoid' the core. The galaxies with emission lines are essentially all late-type galaxies. On the other hand, the emission-line galaxies represent only about a third of the late-type galaxies, the majority of which do not show detectable emission lines. The galaxies without emission lines are therefore a mix of early- and late-type galaxies. In this paper we attempt to separate early- and late-type galaxies, and we study possible differences in distribution and kinematics of the two galaxy classes. For only about 10% of the galaxies in the ENACS, the morphology is known from imaging. Here, we describe our classification on the basis of the ENACS spectrum. The significant information in each spectrum is compressed into 15 Principal Components, which are used as input for an Artificial Neural Network. The latter is trained' with 150 of the 270 galaxies for which a morphological type is available from Dressler, and subsequently used to classify each galaxy. This yields a classification for two-thirds of the ENACS galaxies. The Artificial Neural Network has two output classes: early-type (E+S0) and late-type (S+I) galaxies. We do not distinguish E and S0 galaxies, because these cannot be separated very robustly on the basis of the spectrum. The success rate of the classification is estimated from the sample of 120 galaxies with Dressler morphologies which were not used to train the ANN
13. Gas kinematics in FIRE simulated galaxies compared to spatially unresolved H I observations
Science.gov (United States)
El-Badry, Kareem; Bradford, Jeremy; Quataert, Eliot; Geha, Marla; Boylan-Kolchin, Michael; Weisz, Daniel R.; Wetzel, Andrew; Hopkins, Philip F.; Chan, T. K.; Fitts, Alex; Kereš, Dušan; Faucher-Giguère, Claude-André
2018-06-01
The shape of a galaxy's spatially unresolved, globally integrated 21-cm emission line depends on its internal gas kinematics: galaxies with rotationally supported gas discs produce double-horned profiles with steep wings, while galaxies with dispersion-supported gas produce Gaussian-like profiles with sloped wings. Using mock observations of simulated galaxies from the FIRE project, we show that one can therefore constrain a galaxy's gas kinematics from its unresolved 21-cm line profile. In particular, we find that the kurtosis of the 21-cm line increases with decreasing V/σ and that this trend is robust across a wide range of masses, signal-to-noise ratios, and inclinations. We then quantify the shapes of 21-cm line profiles from a morphologically unbiased sample of ˜2000 low-redshift, H I-detected galaxies with Mstar = 107-11 M⊙ and compare to the simulated galaxies. At Mstar ≳ 1010 M⊙, both the observed and simulated galaxies produce double-horned profiles with low kurtosis and steep wings, consistent with rotationally supported discs. Both the observed and simulated line profiles become more Gaussian like (higher kurtosis and less-steep wings) at lower masses, indicating increased dispersion support. However, the simulated galaxies transition from rotational to dispersion support more strongly: at Mstar = 108-10 M⊙, most of the simulations produce more Gaussian-like profiles than typical observed galaxies with similar mass, indicating that gas in the low-mass simulated galaxies is, on average, overly dispersion supported. Most of the lower-mass-simulated galaxies also have somewhat lower gas fractions than the median of the observed population. The simulations nevertheless reproduce the observed line-width baryonic Tully-Fisher relation, which is insensitive to rotational versus dispersion support.
14. Inverse kinematics for the variable geometry truss manipulator via a Lagrangian dual method
Directory of Open Access Journals (Sweden)
Yanchun Zhao
2016-11-01
Full Text Available This article studies the inverse kinematics problem of the variable geometry truss manipulator. The problem is cast as an optimization process which can be divided into two steps. Firstly, according to the information about the location of the end effector and fixed base, an optimal center curve and the corresponding distribution of the intermediate platforms along this center line are generated. This procedure is implemented by solving a non-convex optimization problem that has a quadratic objective function subject to quadratic constraints. Then, in accordance with the distribution of the intermediate platforms along the optimal center curve, all lengths of the actuators are calculated via the inverse kinematics of each variable geometry truss module. Hence, the approach that we present is an optimization procedure that attempts to generate the optimal intermediate platform distribution along the optimal central curve, while the performance index and kinematic constraints are satisfied. By using the Lagrangian duality theory, a closed-form optimal solution of the original optimization is given. The numerical simulation substantiates the effectiveness of the introduced approach.
15. Autonomous Kinematic Calibration of the Robot Manipulator with a Linear Laser-Vision Sensor
Science.gov (United States)
Kang, Hee-Jun; Jeong, Jeong-Woo; Shin, Sung-Weon; Suh, Young-Soo; Ro, Young-Schick
This paper presents a new autonomous kinematic calibration technique by using a laser-vision sensor called "Perceptron TriCam Contour". Because the sensor measures by capturing the image of a projected laser line on the surface of the object, we set up a long, straight line of a very fine string inside the robot workspace, and then allow the sensor mounted on a robot to measure the point intersection of the line of string and the projected laser line. The data collected by changing robot configuration and measuring the intersection points are constrained to on a single straght line such that the closed-loop calibration method can be applied. The obtained calibration method is simple and accurate and also suitable for on-site calibration in an industrial environment. The method is implemented using Hyundai VORG-35 for its effectiveness.
16. Influence of chronic back pain on kinematic reactions to unpredictable arm pulls.
Science.gov (United States)
Götze, Martin; Ernst, Michael; Koch, Markus; Blickhan, Reinhard
2015-03-01
There is evidence that muscle reflexes are delayed in patients with chronic low back pain in response to perturbations. It is still unrevealed whether these delays accompanied by an altered kinematic or compensated by adaption of other muscle parameters. The aim of this study was to investigate whether chronic low back pain patients show an altered kinematic reaction and if such data are reliable for the classification of chronic low back pain. In an experiment involving 30 females, sudden lateral perturbations were applied to the arm of a subject in an upright, standing position. Kinematics was used to distinguish between chronic low back pain patients and healthy controls. A calculated model of a stepwise discriminant function analysis correctly predicted 100% of patients and 80% of healthy controls. The estimation of the classification error revealed a constant rate for the classification of the healthy controls and a slightly decreased rate for the patients. Observed reflex delays and identified kinematic differences inside and outside the region of pain during impaired movement indicated that chronic low back pain patients have an altered motor control that is not restricted to the lumbo-pelvic region. This applied paradigm of external perturbations can be used to detect chronic low back pain patients and also persons without chronic low back pain but with an altered motor control. Further investigations are essential to reveal whether healthy persons with changes in motor function have an increased potential to develop chronic back pain. Copyright © 2015 Elsevier Ltd. All rights reserved.
17. Temperature Measurements in the Solar Transition Region Using N III Line Intensity Ratios
Science.gov (United States)
Doron, R.; Doschek, G. A.; Laming, J. M.; Feldman, U.; Bhatia, A. K.
2003-01-01
UV emission from B-like N and O ions a rather rare opportunity for recording spectral lines in a narrow wavelength range that can potentially be used to derive temperatures relevant to the solar transition region. In these ions, the line intensity ratios of the type (2s2p(sup 2) - 2p(sup 3)) / (2s(sup 2)2p - 2s2p(sup 2)) are very sensitive to the electron temperature. Additionally, the lines involving the ratios fall within a range of only - 12 A; in N III the lines fall in the 980 - 992 A range and in O IV in the 780 - 791 A range. In this work, we explore the use of these atomic systems, primarily in N III, for temperature diagnostics of the transition region by analyzing UV spectra obtained by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer flown on the Solar and Heliospheric Observatory (SOHO). The N III temperature-sensitive line ratios are measured in more than 60 observations. Most of the measured ratios correspond to temperatures in the range 5.7x10(exp 4) - 6.7x10(exp 4) K. This range is considerably lower than the calculated temperature of maximum abundance of N III, which is approx. 7.6x10(exp 4) K. Detailed analysis of the spectra further indicates that the measured ratios are probably somewhat overestimated due to resonant scattering effects in the 2s(sup 2)2p - 2s2p(sup 2) lines and small blends in the 2s2p(sup 2) - 2p3 lines. Actual lower ratios would only increase the disagreement between the ionization balance calculations and present temperature measurements based on a collisional excitation model. In the case of the O IV spectra, we determined that due to the close proximity in wavelength of the weak line (2s2p(sup 2)-2p3 transitions) to a strong Ne VIII line, sufficiently accurate ratio measurements cannot be obtained. Subject headings: atomic data --- atomic processes --- Sun: transition region --- Sun: U V radiation --- techniques: spectroscopic
18. A DETAILED MORPHO-KINEMATIC MODEL OF THE ESKIMO, NGC 2392: A UNIFYING VIEW WITH THE CAT'S EYE AND SATURN PLANETARY NEBULAE
International Nuclear Information System (INIS)
García-Díaz, Ma. T.; López, J. A.; Steffen, W.; Richer, M. G.
2012-01-01
The three-dimensional and kinematic structure of the Eskimo nebula, NGC 2392, has been notoriously difficult to interpret in detail given its complex morphology, multiple kinematic components and its nearly pole-on orientation along the line of sight. We present a comprehensive, spatially resolved, high-resolution, long-slit spectroscopic mapping of the Eskimo planetary nebula. The data consist of 21 spatially resolved, long-slit echelle spectra tightly spaced over the Eskimo and along its bipolar jets. This data set allows us to construct a velocity-resolved [N II] channel map of the nebula with a resolution of 10 km s –1 that disentangles its different kinematic components. The spectroscopic information is combined with Hubble Space Telescope images to construct a detailed three-dimensional morpho-kinematic model of the Eskimo using the code SHAPE. With this model we demonstrate that the Eskimo is a close analog to the Saturn and the Cat's Eye nebulae, but rotated 90° to the line of sight. Furthermore, we show that the main characteristics of our model apply to the general properties of the group of elliptical planetary nebulae with ansae or FLIERS, once the orientation is considered. We conclude that this kind of nebula belongs to a class with a complex common evolutionary sequence of events.
19. KINEMATIC CLASSIFICATIONS OF LOCAL INTERACTING GALAXIES: IMPLICATIONS FOR THE MERGER/DISK CLASSIFICATIONS AT HIGH-z
International Nuclear Information System (INIS)
Hung, Chao-Ling; Larson, Kirsten L.; Sanders, D. B.; Rich, Jeffrey A.; Yuan, Tiantian; Kewley, Lisa J.; Casey, Caitlin M.; Smith, Howard A.; Hayward, Christopher C.
2015-01-01
The classification of galaxy mergers and isolated disks is key for understanding the relative importance of galaxy interactions and secular evolution during the assembly of galaxies. Galaxy kinematics as traced by emission lines have been used to suggest the existence of a significant population of high-z star-forming galaxies consistent with isolated rotating disks. However, recent studies have cautioned that post-coalescence mergers may also display disk-like kinematics. To further investigate the robustness of merger/disk classifications based on kinematic properties, we carry out a systematic classification of 24 local (U)LIRGs spanning a range of morphologies: from isolated spiral galaxies, ongoing interacting systems, to fully merged remnants. We artificially redshift the Wide Field Spectrograph observations of these local (U)LIRGs to z = 1.5 to make a realistic comparison with observations at high-z, and also to ensure that all galaxies have the same spatial sampling of ∼900 pc. Using both kinemetry-based and visual classifications, we find that the reliability of kinematic classification shows a strong trend with the interaction stage of galaxies. Mergers with two nuclei and tidal tails have the most distinct kinematics compared to isolated disks, whereas a significant population of the interacting disks and merger remnants are indistinguishable from isolated disks. The high fraction of mergers displaying disk-like kinematics reflects the complexity of the dynamics during galaxy interactions. Additional merger indicators such as morphological properties traced by stars or molecular gas are required to further constrain the merger/disk classifications at high-z
20. Biogas infrastructure from farm-scale to regional scale, line-pack storage in biogas grids
NARCIS (Netherlands)
Hengeveld, Evert Jan
2016-01-01
Biogas infrastructure from farm-scale to regional scale, line-pack storage in biogas grids. The number of local and regional initiatives encouraging the production and use of regional produced energy grows. In these new developments biogas can play a role, as a producer of energy, but also in
1. The peculiar A star HD 110066: a photographic region line identification study
International Nuclear Information System (INIS)
1988-01-01
A line identification study of the very sharp-lined peculiar A star HD 110066 has been performed using four high dispersion photographic region spectrograms. New species found include Al I, Si I, S II, Ti I, Co II, Zr II, Cd I, La II, Ce III, Gd III, Dy II, Er II and Tm II. The presence of these species is in accord with the continuity of the magnetic Ap star sequence. (author)
2. Are undesirable contact kinematics minimized after kinematically aligned total knee arthroplasty? An intersurgeon analysis of consecutive patients.
Science.gov (United States)
Howell, Stephen M; Hodapp, Esther E; Vernace, Joseph V; Hull, Maury L; Meade, Thomas D
2013-10-01
Tibiofemoral contact kinematics or knee implant motions have a direct influence on patient function and implant longevity and should be evaluated for any new alignment technique such as kinematically aligned total knee arthroplasty (TKA). Edge loading of the tibial liner and external rotation (reverse of normal) and adduction of the tibial component on the femoral component are undesirable contact kinematics that should be minimized. Accordingly, this study determined whether the overall prevalence of undesirable contact kinematics during standing, mid kneeling near 90 degrees and full kneeling with kinematically aligned TKA are minimal and not different between groups of consecutive patients treated by different surgeons. Three surgeons were asked to perform cemented, kinematically aligned TKA with patient-specific guides in a consecutive series of patients with their preferred cruciate-retaining (CR) implant. In vivo tibiofemoral contact positions were obtained using a 3- to 2-dimensional image registration technique in 69 subjects (Vanguard CR-TKA N = 22, and Triathlon CR-TKA N = 47). Anterior or posterior edge loading of the tibial liner was not observed. The overall prevalence of external rotation of the tibial component on the femoral component of 6 % was low and not different between surgeons (n.s.). The overall prevalence of adduction of the tibial component on the femoral component of 4 % was low and not different between surgeons (n.s.). Kinematically aligned TKA minimized the undesirable contact kinematics of edge loading of the tibial liner, and external rotation and adduction of the tibial component on the femoral component during standing and kneeling, which suggests an optimistic prognosis for durable long-term function. III.
3. Inverse Kinematic Analysis Of A Quadruped Robot
Directory of Open Access Journals (Sweden)
Muhammed Arif Sen
2017-09-01
Full Text Available This paper presents an inverse kinematics program of a quadruped robot. The kinematics analysis is main problem in the manipulators and robots. Dynamic and kinematic structures of quadruped robots are very complex compared to industrial and wheeled robots. In this study inverse kinematics solutions for a quadruped robot with 3 degrees of freedom on each leg are presented. Denavit-Hartenberg D-H method are used for the forward kinematic. The inverse kinematic equations obtained by the geometrical and mathematical methods are coded in MATLAB. And thus a program is obtained that calculate the legs joint angles corresponding to desired various orientations of robot and endpoints of legs. Also the program provides the body orientations of robot in graphical form. The angular positions of joints obtained corresponding to desired different orientations of robot and endpoints of legs are given in this study.
4. Covariant electromagnetic field lines
Science.gov (United States)
Hadad, Y.; Cohen, E.; Kaminer, I.; Elitzur, A. C.
2017-08-01
Faraday introduced electric field lines as a powerful tool for understanding the electric force, and these field lines are still used today in classrooms and textbooks teaching the basics of electromagnetism within the electrostatic limit. However, despite attempts at generalizing this concept beyond the electrostatic limit, such a fully relativistic field line theory still appears to be missing. In this work, we propose such a theory and define covariant electromagnetic field lines that naturally extend electric field lines to relativistic systems and general electromagnetic fields. We derive a closed-form formula for the field lines curvature in the vicinity of a charge, and show that it is related to the world line of the charge. This demonstrates how the kinematics of a charge can be derived from the geometry of the electromagnetic field lines. Such a theory may also provide new tools in modeling and analyzing electromagnetic phenomena, and may entail new insights regarding long-standing problems such as radiation-reaction and self-force. In particular, the electromagnetic field lines curvature has the attractive property of being non-singular everywhere, thus eliminating all self-field singularities without using renormalization techniques.
5. H I Kinematics along the Minor Axis of M82
Science.gov (United States)
Martini, Paul; Leroy, Adam K.; Mangum, Jeffrey G.; Bolatto, Alberto; Keating, Katie M.; Sandstrom, Karin; Walter, Fabian
2018-03-01
M82 is one of the best-studied starburst galaxies in the local universe, and is consequently a benchmark for studying star formation feedback at both low and high redshift. We present new VLA H I observations that reveal the cold gas kinematics along the minor axis in unprecedented detail. This includes the detection of H I up to 10 kpc along the minor axis toward the south and beyond 5 kpc to the north. A surprising aspect of these observations is that the line-of-sight H I velocity decreases substantially from about 120 to 50 {km} {{{s}}}-1 from 1.5 to 10 kpc off the midplane. The velocity profile is not consistent with the H I gas cooling from the hot wind. We demonstrate that the velocity decrease is substantially greater than the deceleration expected from gravitational forces alone. If the H I consists of a continuous population of cold clouds, some additional drag force must be present, and the magnitude of the drag force places a joint constraint on the ratio of the ambient medium to the typical cloud size and density. We also show that the H I kinematics are inconsistent with a simple conical outflow centered on the nucleus, but instead require the more widespread launch of the H I over the ∼1 kpc extent of the starburst region. Regardless of the launch mechanism for the H I gas, the observed velocity decrease along the minor axis is sufficiently great that the H I may not escape the halo of M82. The inferred H I outflow rate at 10 kpc off the midplane is much less than 1 {M}ȯ yr‑1.
6. Investigating The Kinematics of Canids and Felids
Science.gov (United States)
Sur, D.
2016-12-01
For all organisms, metabolic energy is critical for survival. While moving efficiently is a necessity for large carnivores, the influence of kinematics on energy demand remains poorly understood. We measured the kinematics of dogs, wolves, and pumas to detect any differences in their respective energy expenditures. Using 22 kinematic parameters measured on 78 videos, we used one-way ANOVAs and paired T-tests to compare 5 experimental treatments among gaits in dogs (n=11 in 3 breed groups), wolves (n=2), and pumas (n=2). Across the measured parameters, we found greater kinematic similarity than expected among dog breeds and no trend in any of the 22 parameters regarding the effect of steepness on locomotion mechanics. Similarly, treadmill kinematics were nearly identical to those measured during outdoor movement. However, in 3 inches of snow, we observed significant differences (pwolf. When comparing canids (wolves and dogs) to a felid (pumas), we found that pumas and dogs are the most kinematically distinct (differing in 13 of 22 parameters, compared with 5 of 22 for wolves and pumas). Lastly, compared with wolves, walking pumas had larger head angles (p=0.0025), forelimb excursion angles (p=0.0045), and hindlimb excursion angles (p=0.0327). After comparing the energetics of pumas and dogs with their respective kinematics, we noted that less dynamic kinematics result in energy savings. Through tracking the locations and gait behavior of large carnivores, novel sensor technology can reveal how indoor kinematics applies to wild animals and improve the conservation of these species.
7. Inverse Kinematics With Closed Form Solution For Denso Robot Manipulator
Directory of Open Access Journals (Sweden)
Ikhsan Eka Prasetia
2015-03-01
Full Text Available In this paper, the forward kinematics and inverse kinematics used on the Denso robot manipulator which has a 6-DOF. The forward kinematics will result in the desired position by end-effector, while inverse kinematics produce angel on each joint. Inverse kinematics problem are very difficult, therefor to obtain the solution of inverse kinematics using closed form solution with geometry approach. The simulation result obtained from forward kinematics and inverse kinematics is determining desired position by Denso robot manipulator. Forward kinematics produce the desired position by the end-effector. Inverse kinematics produce joint angle, where the inverse kinematics produce eight conditions obtained from closed form solution with geometry approach to reach the desired position by the end-effector.
8. Inverse Kinematics With Closed Form Solution For Denso Robot Manipulator
OpenAIRE
Ikhsan Eka Prasetia; Trihastuti Agustinah
2015-01-01
In this paper, the forward kinematics and inverse kinematics used on the Denso robot manipulator which has a 6-DOF. The forward kinematics will result in the desired position by end-effector, while inverse kinematics produce angel on each joint. Inverse kinematics problem are very difficult, therefor to obtain the solution of inverse kinematics using closed form solution with geometry approach. The simulation result obtained from forward kinematics and inverse kinematics is determining desire...
9. Spatially extended K Iλ7699 emission in the nebula of VY CMa: kinematics and geometry
Science.gov (United States)
Smith, Nathan
2004-04-01
Long-slit echelle spectra reveal bright extended emission from the K Iλ7699 resonance line in the reflection nebula surrounding the extreme red supergiant VY Canis Majoris. The central star has long been known for its unusually bright K I emission lines, but this is the first report of intrinsic emission from K I in the nebula. The extended emission is not just a reflected spectrum of the star, but is due to resonant scattering by K atoms in the outer nebula itself, and is therefore a valuable probe of the kinematics and geometry of the circumstellar environment of VY CMa. Dramatic velocity structure is seen in the long-slit spectra, and most lines of sight through the nebula intersect multiple distinct velocity components. A faint halo' at large distances from the star does appear to show a reflected spectrum, however, and suggests a systemic velocity of +40 km s-1 with respect to the Sun. The most striking feature is blueshifted emission from the filled interior of a large shell seen in images; the kinematic structure is reminiscent of a Hubble flow, and provides strong evidence for asymmetric and episodic mass loss due to localized eruptions on the stellar surface.
10. The Kinematics of Multiple-peaked Lyα Emission in Star-forming Galaxies at z ~ 2-3
Science.gov (United States)
Kulas, Kristin R.; Shapley, Alice E.; Kollmeier, Juna A.; Zheng, Zheng; Steidel, Charles C.; Hainline, Kevin N.
2012-01-01
We present new results on the Lyα emission-line kinematics of 18 z ~ 2-3 star-forming galaxies with multiple-peaked Lyα profiles. With our large spectroscopic database of UV-selected star-forming galaxies at these redshifts, we have determined that ~30% of such objects with detectable Lyα emission display multiple-peaked emission profiles. These profiles provide additional constraints on the escape of Lyα photons due to the rich velocity structure in the emergent line. Despite recent advances in modeling the escape of Lyα from star-forming galaxies at high redshifts, comparisons between models and data are often missing crucial observational information. Using Keck II NIRSPEC spectra of Hα (z ~ 2) and [O III]λ5007 (z ~ 3), we have measured accurate systemic redshifts, rest-frame optical nebular velocity dispersions, and emission-line fluxes for the objects in the sample. In addition, rest-frame UV luminosities and colors provide estimates of star formation rates and the degree of dust extinction. In concert with the profile sub-structure, these measurements provide critical constraints on the geometry and kinematics of interstellar gas in high-redshift galaxies. Accurate systemic redshifts allow us to translate the multiple-peaked Lyα profiles into velocity space, revealing that the majority (11/18) display double-peaked emission straddling the velocity-field zero point with stronger red-side emission. Interstellar absorption-line kinematics suggest the presence of large-scale outflows for the majority of objects in our sample, with an average measured interstellar absorption velocity offset of langΔv absrang = -230 km s-1. A comparison of the interstellar absorption kinematics for objects with multiple- and single-peaked Lyα profiles indicate that the multiple-peaked objects are characterized by significantly narrower absorption line widths. We compare our data with the predictions of simple models for outflowing and infalling gas distributions around
11. TIMASSS: the IRAS 16293-2422 millimeter and submillimeter spectral survey. I. Observations, calibration, and analysis of the line kinematics
NARCIS (Netherlands)
Caux, E.; Kahane, C.; Castets, A.; Coutens, A.; Ceccarelli, C.; Bacmann, A.; Bisschop, S.; Bottinelli, S.; Comito, C.; Helmich, F. P.; Lefloch, B.; Parise, B.; Schilke, P.; Tielens, A. G. G. M.; van Dishoeck, E.; Vastel, C.; Wakelam, V.; Walters, A.
Context. Unbiased spectral surveys are powerful tools to study the chemistry and the physics of star forming regions, because they can provide a complete census of the molecular content and the observed lines probe the physical structure of the source. Aims. While unbiased surveys at the millimeter
12. KINEMATIC ANALYSIS OF LINE-OUT THROWING IN ELITE INTERNATIONAL RUGBY UNION
Directory of Open Access Journals (Sweden)
Mark G.L. Sayers
2011-09-01
Full Text Available The rugby union line-out is a key aspect of game play and involves players from both teams contesting for the ball after it has been thrown in from the side line. Successful lines-out throws require the ball to be delivered accurately to the hands of a jumping and/or lifted team mate (approximately 3-3.5 m off the ground over distances of between 5- 18 m. Previous research has suggested considerable inter and intra-individual differences in the throwing techniques of international level players. Accordingly, this project investigated the interrelationships between accuracy and the line-out throwing characteristics of three elite international rugby players, and then analyzed whether these changed for throws over increasing length. Three-dimensional (3D data were developed from video footage (50 Hz of three elite international subjects for 30 throws over three distances (6 m, 10 m, and 15 m. Results showed notable differences between subjects in many variables at each of the key throw phases. However, several variables such as the degree of trunk flexion at the end of the backswing and at ball release, coupled with elbow flexion angle at ball release remained constant as throw length increased. All subjects exhibited high levels of consistency in movement patterns across all throw lengths. Findings indicated that these high performance line-out throwers shared several common characteristics that will provide useful guides in the development of training programs
13. On the kinematic reconstruction of deep inelastic scattering at HERA: the Σmethod
International Nuclear Information System (INIS)
Bassler, U.; Bernardi, G.
1994-12-01
We review and compare the reconstruction methods of the inclusive deep inelastic scattering variables used at HERA. We introduce a new prescription, the Sigma (Σ) method, which allows to measure the structure function of the proton F 2 (x, Q 2 ) in a large kinematic domain, and in particular in the low x-low Q 2 region, with small systematic errors and small radiative corrections. A detailed comparison between the Σ method and the other methods is shown. Extensions of the Σ method are presented. The effect of QED radiation on the kinematic reconstruction and on the structure function measurement is discussed. (orig.)
14. Evolution of upper limb kinematics four years after subacute robot-assisted rehabilitation in stroke patients.
Science.gov (United States)
Pila, Ophélie; Duret, Christophe; Gracies, Jean-Michel; Francisco, Gerard E; Bayle, Nicolas; Hutin, Émilie
2018-04-25
To assess functional status and robot-based kinematic measures four years after subacute robot-assisted rehabilitation in hemiparesis. Twenty-two patients with stroke-induced hemiparesis underwent a ≥3-month upper limb combined program of robot-assisted and occupational therapy from two months post-stroke, and received community-based therapy after discharge. Four years later, 19 (86%) participated in this follow-up study. Assessments 2, 5 and 54 months post-stroke included Fugl-Meyer (FM), Modified Frenchay Scale (MFS, at Month 54) and robot-based kinematic measures of targeting tasks in three directions, north, paretic and non-paretic: distance covered, velocity, accuracy (root mean square (RMS) error from straight line) and smoothness (number of velocity peaks; upward changes in accuracy and smoothness represent worsening). Analysis was stratified by FM score at two months: ≥17 (Group 1) or Kinematic changes (three directions pooled) were: distance -1[-17;2]% (ns); velocity, -8[-32;28]% (ns); accuracy, +6[-13;98]% (ns); smoothness, +44[-6;126]% (p robot-assisted upper limb training during subacute post-stroke phase, movement kinematics deteriorated despite community-based therapy, especially in more severely impaired patients. EudraCT 2016-005121-36. Registration: 2016-12-20. Date of enrolment of the first participant to the trial: 2009-11-24.
15. NARROW-LINE-WIDTH UV BURSTS IN THE TRANSITION REGION ABOVE SUNSPOTS OBSERVED BY IRIS
Energy Technology Data Exchange (ETDEWEB)
Hou, Zhenyong; Huang, Zhenghua; Xia, Lidong; Li, Bo; Madjarska, Maria S.; Fu, Hui; Mou, Chaozhou; Xie, Haixia, E-mail: z.huang@sdu.edu.cn, E-mail: xld@sdu.edu.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209 Shandong (China)
2016-10-01
Various small-scale structures abound in the solar atmosphere above active regions, playing an important role in the dynamics and evolution therein. We report on a new class of small-scale transition region structures in active regions, characterized by strong emissions but extremely narrow Si iv line profiles as found in observations taken with the Interface Region Imaging Spectrograph (IRIS). Tentatively named as narrow-line-width UV bursts (NUBs), these structures are located above sunspots and comprise one or multiple compact bright cores at sub-arcsecond scales. We found six NUBs in two data sets (a raster and a sit-and-stare data set). Among these, four events are short-lived with a duration of ∼10 minutes, while two last for more than 36 minutes. All NUBs have Doppler shifts of 15–18 km s{sup −1}, while the NUB found in sit-and-stare data possesses an additional component at ∼50 km s{sup −1} found only in the C ii and Mg ii lines. Given that these events are found to play a role in the local dynamics, it is important to further investigate the physical mechanisms that generate these phenomena and their role in the mass transport in sunspots.
16. Trajectory control of robot manipulators with closed-kinematic chain mechanism
Science.gov (United States)
Nguyen, Charles C.; Pooran, Farhad J.; Premack, Timothy
1987-01-01
The problem of Cartesian trajectory control of a closed-kinematic chain mechanism robot manipulator, recently built at CAIR to study the assembly of NASA hardware for the future Space Station, is considered. The study is performed by both computer simulation and experimentation for tracking of three different paths: a straight line, a sinusoid, and a circle. Linearization and pole placement methods are employed to design controller gains. Results show that the controllers are robust and there are good agreements between simulation and experimentation. The results also show excellent tracking quality and small overshoots.
17. TIME DEPENDENT NONEQUILIBRIUM IONIZATION OF TRANSITION REGION LINES OBSERVED WITH IRIS
Energy Technology Data Exchange (ETDEWEB)
Martínez-Sykora, Juan; Pontieu, Bart De; Hansteen, Viggo H. [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304 (United States); Gudiksen, Boris, E-mail: j.m.sykora@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway)
2016-01-20
The properties of nonstatistical equilibrium ionization of silicon and oxygen ions are analyzed in this work. We focus on five solar targets (quiet Sun; coronal hole; plage; quiescent active region, AR; and flaring AR) as observed with the Interface Region Imaging Spectrograph (IRIS). IRIS is best suited for this work owing to the high cadence (up to 0.5 s), high spatial resolution (up to 0.″32), and high signal-to-noise ratios for O iv λ1401 and Si iv λ1402. We find that the observed intensity ratio between lines of three times ionized silicon and oxygen ions depends on their total intensity and that this correlation varies depending on the region observed (quiet Sun, coronal holes, plage, or active regions) and on the specific observational objects present (spicules, dynamic loops, jets, microflares, or umbra). In order to interpret the observations, we compare them with synthetic profiles taken from 2D self-consistent radiative MHD simulations of the solar atmosphere, where the statistical equilibrium or nonequilibrium treatment of silicon and oxygen is applied. These synthetic observations show vaguely similar correlations to those in the observations, i.e., between the intensity ratios and their intensities, but only in the nonequilibrium case do we find that (some of) the observations can be reproduced. We conclude that these lines are formed out of statistical equilibrium. We use our time-dependent nonequilibrium ionization simulations to describe the physical mechanisms behind these observed properties.
18. HIGH-VELOCITY LINE FORMING REGIONS IN THE TYPE Ia SUPERNOVA 2009ig
International Nuclear Information System (INIS)
Marion, G. H.; Foley, Ryan J.; Challis, Peter; Kirshner, Robert P.; Vinko, Jozsef; Wheeler, J. Craig; Silverman, Jeffrey M.; Hsiao, Eric Y.; Brown, Peter J.; Filippenko, Alexei V.; Garnavich, Peter; Landsman, Wayne B.; Parrent, Jerod T.; Pritchard, Tyler A.; Roming, Peter W. A.; Wang, Xiaofeng
2013-01-01
We report measurements and analysis of high-velocity (HVF) (>20,000 km s –1 ) and photospheric absorption features in a series of spectra of the Type Ia supernova (SN) 2009ig obtained between –14 days and +13 days with respect to the time of maximum B-band luminosity (B-max). We identify lines of Si II, Si III, S II, Ca II, and Fe II that produce both HVF and photospheric-velocity (PVF) absorption features. SN 2009ig is unusual for the large number of lines with detectable HVF in the spectra, but the light-curve parameters correspond to a slightly overluminous but unexceptional SN Ia (M B = –19.46 mag and Δm 15 (B) = 0.90 mag). Similarly, the Si II λ6355 velocity at the time of B-max is greater than 'normal' for an SN Ia, but it is not extreme (v Si = 13,400 km s –1 ). The –14 days and –13 days spectra clearly resolve HVF from Si II λ6355 as separate absorptions from a detached line forming region. At these very early phases, detached HVF are prevalent in all lines. From –12 days to –6 days, HVF and PVF are detected simultaneously, and the two line forming regions maintain a constant separation of about 8000 km s –1 . After –6 days all absorption features are PVF. The observations of SN 2009ig provide a complete picture of the transition from HVF to PVF. Most SNe Ia show evidence for HVF from multiple lines in spectra obtained before –10 days, and we compare the spectra of SN 2009ig to observations of other SNe. We show that each of the unusual line profiles for Si II λ6355 found in early-time spectra of SNe Ia correlate to a specific phase in a common development sequence from HVF to PVF
19. THE SIZE, STRUCTURE, AND IONIZATION OF THE BROAD-LINE REGION IN NGC 3227
International Nuclear Information System (INIS)
Devereux, Nick
2013-01-01
20. Morphology and kinematics of filaments in Serpens and Perseus molecular clouds: a high resolution study
Science.gov (United States)
Dhabal, Arnab; Mundy, Lee; Rizzo, Maxime; Storm, Shaye; Teuben, Peter; CLASSy Collaboration
2018-01-01
Filamentary structures are prevalent in molecular clouds over a wide range of scales, and are often associated with active star formation. The study of filament morphology and kinematics provide insights into the physical processes leading to core formation in clustered environments. As part of the CARMA Large Area Star Formation Survey (CLASSy) follow-up, we observed five Herschel filaments in the Serpens Main, Serpens South and NGC1333 molecular clouds using the J=1-0 transitions of dense gas tracers H13CO+, HNC and H13CN. Of these, H13CO+ and H13CN are optically thin and serve as a test of the kinematics previously seen by the CLASSy in N2H+. The observations have an angular resolution of 7'' and a spectral resolution of 0.16 km/s. Although the large scale structure compares well with the CARMA N2H+ (J=1-0) maps and Herschel dust continuum maps, we resolve finer structure within the filaments identified by Herschel. Most regions are found to have multiple structures and filaments partially overlapping in the line-of-sight. In two regions overlapping structures have velocity differences as high as 1.4 km/s. We identify 8 individual filaments with typical widths of 0.03-0.06 pc in these tracers, which is significantly less than widths observed in the Herschel dust column density maps. At least 50% of the filaments have distinct velocity gradients perpendicular to their major axis with average values in the range 4-10 km s-1 pc-1. These findings are in support of the theoretical models of filament formation by 2-D inflow in the shock layer created by colliding turbulent cells. We also find evidence of velocity gradients along the length of two filaments; the gradients suggest that these filaments are inflowing towards the cloud core.
1. Extended Emission-Line Regions: Remnants of Quasar Superwinds?
Science.gov (United States)
Fu, Hai; Stockton, Alan
2009-01-01
We give an overview of our recent integral-field-unit spectroscopy of luminous extended emission-line regions (EELRs) around low-redshift quasars, including new observations of five fields. Previous work has shown that the most luminous EELRs are found almost exclusively around steep-spectrum radio-loud quasars, with apparently disordered global velocity fields, and little, if any, morphological correlation with either the host galaxy or the radio structure. Our new observations confirm and expand these results. The EELRs often show some clouds with velocities exceeding 500 km s-1, ranging up to 1100 km s-1, but the velocity dispersions, with few exceptions, are in the 30-100 km s-1 range. Emission-line ratios show that the EELRs are clearly photoionized by the quasars. Masses of the EELRs range up to 1010Msun. Essentially all of the EELRs show relatively low metallicities, and they are associated with quasars that, in contrast to most, show similarly low metallicities in their broad-line regions. The two objects in our sample that do not have classical double-lobed radio morphologies (3C 48, with a compact-steep-spectrum source; Mrk 1014, radio quiet, but with a weak compact-steep-spectrum source) are the only ones that appear to have recent star formation. While some of the less luminous EELRs may have other origins, the most likely explanation for those in our sample is that they are examples of gas swept out of the host galaxy by a large-solid-angle blast wave accompanying the production of the radio jets. The triggering of the quasar activity is almost certainly the result of the merger of a gas-rich galaxy with a massive, gas-poor galaxy hosting the supermassive black hole. Based in part on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the
2. A spatio-kinematic study of the interaction of the planetary nebula NGC 246 with the interstellar medium
NARCIS (Netherlands)
Muthu, C; Anandarao, BG; Pottasch, [No Value
Spatio-Kinematic observations were made on NGC 246 in the [OIII] 5007 Angstrom line using an Imaging Fabry-Perot Spectrometer. Evidence for the deceleration effect was found in the leading edge of the nebular shell, possibly due to its interaction with the interstellar medium. Further, we show that
3. The Emotional Modulation of Facial Mimicry: A Kinematic Study
Directory of Open Access Journals (Sweden)
Antonella Tramacere
2018-01-01
Full Text Available It is well-established that the observation of emotional facial expression induces facial mimicry responses in the observers. However, how the interaction between emotional and motor components of facial expressions can modulate the motor behavior of the perceiver is still unknown. We have developed a kinematic experiment to evaluate the effect of different oro-facial expressions on perceiver's face movements. Participants were asked to perform two movements, i.e., lip stretching and lip protrusion, in response to the observation of four meaningful (i.e., smile, angry-mouth, kiss, and spit and two meaningless mouth gestures. All the stimuli were characterized by different motor patterns (mouth aperture or mouth closure. Response Times and kinematics parameters of the movements (amplitude, duration, and mean velocity were recorded and analyzed. Results evidenced a dissociated effect on reaction times and movement kinematics. We found shorter reaction time when a mouth movement was preceded by the observation of a meaningful and motorically congruent oro-facial gesture, in line with facial mimicry effect. On the contrary, during execution, the perception of smile was associated with the facilitation, in terms of shorter duration and higher velocity of the incongruent movement, i.e., lip protrusion. The same effect resulted in response to kiss and spit that significantly facilitated the execution of lip stretching. We called this phenomenon facial mimicry reversal effect, intended as the overturning of the effect normally observed during facial mimicry. In general, the findings show that both motor features and types of emotional oro-facial gestures (conveying positive or negative valence affect the kinematics of subsequent mouth movements at different levels: while congruent motor features facilitate a general motor response, motor execution could be speeded by gestures that are motorically incongruent with the observed one. Moreover, valence
4. The Emotional Modulation of Facial Mimicry: A Kinematic Study.
Science.gov (United States)
Tramacere, Antonella; Ferrari, Pier F; Gentilucci, Maurizio; Giuffrida, Valeria; De Marco, Doriana
2017-01-01
It is well-established that the observation of emotional facial expression induces facial mimicry responses in the observers. However, how the interaction between emotional and motor components of facial expressions can modulate the motor behavior of the perceiver is still unknown. We have developed a kinematic experiment to evaluate the effect of different oro-facial expressions on perceiver's face movements. Participants were asked to perform two movements, i.e., lip stretching and lip protrusion, in response to the observation of four meaningful (i.e., smile, angry-mouth, kiss, and spit) and two meaningless mouth gestures. All the stimuli were characterized by different motor patterns (mouth aperture or mouth closure). Response Times and kinematics parameters of the movements (amplitude, duration, and mean velocity) were recorded and analyzed. Results evidenced a dissociated effect on reaction times and movement kinematics. We found shorter reaction time when a mouth movement was preceded by the observation of a meaningful and motorically congruent oro-facial gesture, in line with facial mimicry effect. On the contrary, during execution, the perception of smile was associated with the facilitation, in terms of shorter duration and higher velocity of the incongruent movement, i.e., lip protrusion. The same effect resulted in response to kiss and spit that significantly facilitated the execution of lip stretching. We called this phenomenon facial mimicry reversal effect , intended as the overturning of the effect normally observed during facial mimicry. In general, the findings show that both motor features and types of emotional oro-facial gestures (conveying positive or negative valence) affect the kinematics of subsequent mouth movements at different levels: while congruent motor features facilitate a general motor response, motor execution could be speeded by gestures that are motorically incongruent with the observed one. Moreover, valence effect depends on
5. Are Proplyds the Low-Energy Counterpart of Clouds Populating the AGNs Broad Line Region?
Science.gov (United States)
Dottori, H.
2000-11-01
The stability of the clouds producing the broadening of permitted lines in A GNs is a challenge for the persistence of these features during the galactic nucleus active fase lifetime. The formation of succesive generations of clouds in this very agressive enviroment, seems not to be the more adequated scenarion to explain this phenomenon. Why should new clouds be formed in regions where the UV radiation is so intense as to destroy the previously existing ones? The discovery of proplyds in Orion and NGC3603, as well as in 30Dor, shows that the formation of stars with protostars with surrounding disk is a common phenomenon in HII regions with very different radiation fields. We discuss that as a mechanism to explain the persistence of the clouds in the AGNs broad line regions.
6. Relationship between Lower Limb Angular Kinematic Variables and the Effectiveness of Sprinting during the Acceleration Phase
Directory of Open Access Journals (Sweden)
Artur Struzik
2016-01-01
Full Text Available The ability to reach a high running velocity over a short distance is essential to a high playing performance in team games. The aim of this study was to determine the relationship between running time over a 10-meter section of a 30-meter sprint along a straight line and changes in the angle and angular velocity that were observed in the ankle, knee, and hip joints. The possible presence may help to optimize motion efficiency during acceleration sprint phase. Eighteen girls involved in team sports were examined in the study. The Fusion Smart Speed System was employed for running time measurements. The kinematic data were recorded using the Noraxon MyoMotion system. Statistically significant relationships were found between running time over a 10-meter section and the kinematic variables of hip and ankle joints. An excessively large flexion in hip joints might have an unfavorable effect on running time during the acceleration phase. Furthermore, in order to minimize running time during the acceleration phase, stride should be maintained along a line (a straight line rather than from side to side. It is also necessary to ensure an adequate range of motion in the hip and ankle joints with respect to the sagittal axis.
7. Relationship between Lower Limb Angular Kinematic Variables and the Effectiveness of Sprinting during the Acceleration Phase.
Science.gov (United States)
Struzik, Artur; Konieczny, Grzegorz; Stawarz, Mateusz; Grzesik, Kamila; Winiarski, Sławomir; Rokita, Andrzej
2016-01-01
The ability to reach a high running velocity over a short distance is essential to a high playing performance in team games. The aim of this study was to determine the relationship between running time over a 10-meter section of a 30-meter sprint along a straight line and changes in the angle and angular velocity that were observed in the ankle, knee, and hip joints. The possible presence may help to optimize motion efficiency during acceleration sprint phase. Eighteen girls involved in team sports were examined in the study. The Fusion Smart Speed System was employed for running time measurements. The kinematic data were recorded using the Noraxon MyoMotion system. Statistically significant relationships were found between running time over a 10-meter section and the kinematic variables of hip and ankle joints. An excessively large flexion in hip joints might have an unfavorable effect on running time during the acceleration phase. Furthermore, in order to minimize running time during the acceleration phase, stride should be maintained along a line (a straight line) rather than from side to side. It is also necessary to ensure an adequate range of motion in the hip and ankle joints with respect to the sagittal axis.
8. Raft cultivation area extraction from high resolution remote sensing imagery by fusing multi-scale region-line primitive association features
Science.gov (United States)
Wang, Min; Cui, Qi; Wang, Jie; Ming, Dongping; Lv, Guonian
2017-01-01
In this paper, we first propose several novel concepts for object-based image analysis, which include line-based shape regularity, line density, and scale-based best feature value (SBV), based on the region-line primitive association framework (RLPAF). We then propose a raft cultivation area (RCA) extraction method for high spatial resolution (HSR) remote sensing imagery based on multi-scale feature fusion and spatial rule induction. The proposed method includes the following steps: (1) Multi-scale region primitives (segments) are obtained by image segmentation method HBC-SEG, and line primitives (straight lines) are obtained by phase-based line detection method. (2) Association relationships between regions and lines are built based on RLPAF, and then multi-scale RLPAF features are extracted and SBVs are selected. (3) Several spatial rules are designed to extract RCAs within sea waters after land and water separation. Experiments show that the proposed method can successfully extract different-shaped RCAs from HR images with good performance.
9. Kinematic aspects of pion-nucleus elastic scattering
International Nuclear Information System (INIS)
Weiss, D.L.; Ernst, D.J.
1982-01-01
The inclusion of relativistic kinematics in the theory of elastic scattering of pions from nuclei is examined. The investigation is performed in the context of the first order impulse approximation which incorporates the following features: (1) Relative momentum are defined according to relativistic theories consistent with time reversal invariance. (2) The two-nucleon interaction is a new, multichannel, separable potential model consistent with the most recent data derived from a recent nonpotential model of Ernst and Johnson. (3) The recoil of the pion-nucleon interacting pair and its resultant nonlocality are included. (4) The Fermi integral is treated by an optimal factorization approximation. It is shown how a careful definition of an intrinsic target density leads to an unambiguous method for including the recoil of the target. The target recoil corrections are found to be large for elastic scattering from 4 He and not negligible for scattering from 12 C. Relativistic potential theory kinematics, kinematics which result from covariant reduction approaches, and kinematics which result from replacing masses by energies in nonrelativistic formulas are compared. The relativistic potential theory kinematics and covariant reduction kinematics are shown to produce different elastic scattering at all pion energies examined (T/sub π/<300 MeV). Simple extensions of nonrelativistic kinematics are found to be reasonable approximations to relativistic potential theory
10. COMPLEX GAS KINEMATICS IN COMPACT, RAPIDLY ASSEMBLING STAR-FORMING GALAXIES
Energy Technology Data Exchange (ETDEWEB)
Amorin, R.; Vilchez, J. M.; Perez-Montero, E. [Instituto de Astrofisica de Andalucia-CSIC, Glorieta de la Astronomia S/N, E-18008 Granada (Spain); Haegele, G. F.; Firpo, V. [Facultad de Ciencias Astronomicas y Geofisicas, Universidad de la Plata, Paseo del Bosque S/N, 1900 La Plata (Argentina); Papaderos, P., E-mail: amorin@iaa.es [Centro de Astrofisica and Faculdade de Ciencias, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal)
2012-08-01
Deep, high-resolution spectroscopic observations have been obtained for six compact, strongly star-forming galaxies at redshift z {approx} 0.1-0.3, most of them also known as green peas. Remarkably, these galaxies show complex emission-line profiles in the spectral region including H{alpha}, [N II] {lambda}{lambda}6548, 6584, and [S II] {lambda}{lambda}6717, 6731, consisting of the superposition of different kinematical components on a spatial extent of few kiloparsecs: a very broad line emission underlying more than one narrower component. For at least two of the observed galaxies some of these multiple components are resolved spatially in their two-dimensional spectra, whereas for another one a faint detached H{alpha} blob lacking stellar continuum is detected at the same recessional velocity {approx}7 kpc away from the galaxy. The individual narrower H{alpha} components show high intrinsic velocity dispersion ({sigma} {approx} 30-80 km s{sup -1}), suggesting together with unsharped masking Hubble Space Telescope images that star formation proceeds in an ensemble of several compact and turbulent clumps, with relative velocities of up to {approx}500 km s{sup -1}. The broad underlying H{alpha} components indicate in all cases large expansion velocities (full width zero intensity {>=}1000 km s{sup -1}) and very high luminosities (up to {approx}10{sup 42} erg s{sup -1}), probably showing the imprint of energetic outflows from supernovae. These intriguing results underline the importance of green peas for studying the assembly of low-mass galaxies near and far.
11. The Impact of the Support System’s Kinematic Structure on Selected Kinematic and Dynamic Quantities of an Experimental Crane
Directory of Open Access Journals (Sweden)
2014-12-01
Full Text Available This paper presents a comparative analysis of two kinematic structures of the support system (with supports with bilateral and unilateral constraints, which were used in an experimental model of a crane. The computational model was developed by using the ADAMS software. The impact of the kinematic structure of the support system on selected kinematic and dynamic values that were recorded during the slewing motion was analysed. It was found, among other things, that an increased number of degrees of freedom of the support system leads to multiple distortions of time characteristics of kinematic and dynamic quantities.
12. Analytic structure of the n=7 scattering amplitude in N=4 SYM theory in multi-Regge kinematics. Conformal Regge cut contribution
International Nuclear Information System (INIS)
Bartels, Jochen; Kormilitzin, Andrey; Oxford Univ.; Lipatov, Lev N.; Oxford Univ.; St. Petersburg State Univ.
2014-11-01
In this second part of our investigation of the analytic structure of the 2→5 scattering amplitude in the planar limit of N=4 SYM in multi-Regge kinematics we compute, in all kinematic regions, the Regge cut contributions in leading order. The results are infrared finite and conformally invariant.
13. Survey for C-Band High Spectral Lines with the Arecibo Telescope
Science.gov (United States)
Tan, Wei Siang
High-mass stars have masses greater than 8 solar masses and are the main source of heavy elements such as iron in the interstellar medium. This type of stars form in giant molecular clouds. Studying the molecular environment in star-forming regions is crucial to understand the physical structure and conditions that lead to the formation of high-mass stars. This thesis presents observations conducted with the 305m Arecibo Telescope in Puerto Rico of twelve high-mass star forming regions. Every source was observed in multiple transitions of molecular species including CH, CH3OH, H2CS, and OH lines, and a radio recombination line. The observations were conducted with the C-Band High receiver of the Arecibo Telescope in the frequency range of 6.0 to 7.4GHz. The goals of the observations were to investigate the detectability of different molecular species (including new possible molecular masers) and obtain high sensitivity observations of the 6.7GHz CH3OH line to detect absorption and use it as a probe of the kinematics of the molecular material with respect to the ionized gas. Among the results of the observations, we report detection of 6.7GHz CH3OH masers toward nine regions, OH masers toward five sources, 6.7GHz CH3OH absorption toward four sources (including tentative detections), and detection of H2CS toward the star forming region G34.26+0.15. We also found a variable and recurrent 6.7GHz CH3OH maser in G45.12+0.13. The 6.7GHz CH 3OH and 6278.65MHz H2CS absorption lines were modeled using the radiative transfer code RADEX to investigate the physical conditions of the molecular clouds responsible for the absorption lines. Our analysis of the absorption lines supports the interpretation that the spectral lines are tracing molecular envelopes of HII regions. In the case of 6.7GHz CH 3OH absorption, our results and data from an extensive literature review indicate that absorption is rare, but that a population of 6.7GHz CH 3OH absorbers may be present at levels
14. JFKengine: A Jacobian and Forward Kinematics Generator
Energy Technology Data Exchange (ETDEWEB)
Fischer, K.N.
2003-02-13
During robot path planning and control the equations that describe the robot motions are determined and solved. Historically these expressions were derived analytically off-line. For robots that must adapt to their environment or perform a wide range of tasks, a way is needed to rapidly re-derive these expressions to take into account the robot kinematic changes, such as when a tool is added to the end-effector. The JFKengine software was developed to automatically produce the expressions representing the manipulator arm motion, including the manipulator arm Jacobian and the forward kinematic expressions. Its programming interface can be used in conjunction with robot simulation software or with robot control software. Thus, it helps to automate the process of configuration changes for serial robot manipulators. If the manipulator undergoes a geometric change, such as tool acquisition, then JFKengine can be invoked again from the control or simulation software, passing it parameters for the new arm configuration. This report describes the automated processes that are implemented by JFKengine to derive the kinematic equations and the programming interface by which it is invoked. Then it discusses the tree data structure that was chosen to store the expressions, followed by several examples of portions of expressions as represented in the tree. The C++ classes and their methods that implement the expression differentiation and evaluation operations are described. The algorithms used to construct the Jacobian and forward kinematic equations using these basic building blocks are then illustrated. The activity described in this report is part of a larger project entitled ''Multi-Optimization Criteria-Based Robot Behavioral Adaptability and Motion Planning'' that focuses on the development of a methodology for the generalized resolution of robot motion equations with time-varying configurations, constraints, and task objective criteria. A specific
15. Kinematic relations in heavy-ion reactions
International Nuclear Information System (INIS)
Gippner, P.; Kalpakchieva, R.
1988-01-01
The present work gives a short overview of the non-relativistic kinematics of nuclear reactions derived on the basis of the conservation laws of energy and linear momentum. Section 2 contains kinematic relations valid for two-body reactions, sections 3 makes use of these relations to describe sequential fission as a special case of reactions with three particles in the exit channel. It is the aim of this work to comprise the kinematic formulae essential for planning of experiments, data analysis and critical examination of the obtained results. (author)
16. [O III] EMISSION AND GAS KINEMATICS IN A LYMAN-ALPHA BLOB AT z {approx} 3.1
Energy Technology Data Exchange (ETDEWEB)
McLinden, Emily M. [McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States); Malhotra, Sangeeta; Rhoads, James E. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Hibon, Pascale [Gemini Observatory, La Serena (Chile); Weijmans, Anne-Marie [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Tilvi, Vithal [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)
2013-04-10
We present spectroscopic measurements of the [O III] emission line from two subregions of strong Ly{alpha} emission in a radio-quiet Lyman-alpha blob (LAB). The blob under study is LAB1 at z {approx} 3.1, and the [O III] detections are from the two Lyman break galaxies (LBGs) embedded in the blob halo. The [O III] measurements were made with LUCIFER on the 8.4 m Large Binocular Telescope and NIRSPEC on 10 m Keck Telescope. Comparing the redshift of the [O III] measurements to Ly{alpha} redshifts from SAURON allows us to take a step toward understanding the kinematics of the gas in the blob. Using both LUCIFER and NIRSPEC we find velocity offsets between the [O III] and Ly{alpha} redshifts that are modestly negative or consistent with 0 km s{sup -1} in both subregions studied (ranging from -72 {+-} 42- + 6 {+-} 33 km s{sup -1}). A negative offset means Ly{alpha} is blueshifted with respect to [O III] a positive offset then implies Ly{alpha} is redshifted with respect to [O III]. These results may imply that outflows are not primarily responsible for Lyman alpha escape in this LAB, since outflows are generally expected to produce a positive velocity offset. In addition, we present an [O III] line flux upper limit on a third region of LAB1, a region that is unassociated with any underlying galaxy. We find that the [O III] upper limit from the galaxy-unassociated region of the blob is at least 1.4-2.5 times fainter than the [O III] flux from one of the LBG-associated regions and has an [O III] to Ly{alpha} ratio measured at least 1.9-3.4 times smaller than the same ratio measured from one of the LBGs.
17. Line profile studies of hydrodynamical models of cometary compact H II regions
International Nuclear Information System (INIS)
Zhu, Feng-Yao; Zhu, Qing-Feng
2015-01-01
We simulate the evolution of cometary H II regions based on several champagne flow models and bow shock models, and calculate the profiles of the [Ne II] fine-structure line at 12.81 μm, the H30α recombination line and the [Ne III] fine-structure line at 15.55 μm for these models at different inclinations of 0°, 30° and 60°. We find that the profiles in the bow shock models are generally different from those in the champagne flow models, but the profiles in the bow shock models with lower stellar velocity (≤ 5 km s −1 ) are similar to those in the champagne flow models. In champagne flow models, both the velocity of peak flux and the flux weighted central velocities of all three lines point outward from molecular clouds. In bow shock models, the directions of these velocities depend on the speed of stars. The central velocities of these lines are consistent with the stellar motion in the high stellar speed cases, but they are opposite directions from the stellar motion in the low speed cases. We notice that the line profiles from the slit along the symmetrical axis of the projected 2D image of these models are useful for distinguishing bow shock models from champagne flow models. It is also confirmed by the calculation that the flux weighted central velocity and the line luminosity of the [Ne III] line can be estimated from the [Ne II] line and the H30α line. (paper)
18. Speeding up the learning of robot kinematics through function decomposition.
Science.gov (United States)
Ruiz de Angulo, Vicente; Torras, Carme
2005-11-01
The main drawback of using neural networks or other example-based learning procedures to approximate the inverse kinematics (IK) of robot arms is the high number of training samples (i.e., robot movements) required to attain an acceptable precision. We propose here a trick, valid for most industrial robots, that greatly reduces the number of movements needed to learn or relearn the IK to a given accuracy. This trick consists in expressing the IK as a composition of learnable functions, each having half the dimensionality of the original mapping. Off-line and on-line training schemes to learn these component functions are also proposed. Experimental results obtained by using nearest neighbors and parameterized self-organizing map, with and without the decomposition, show that the time savings granted by the proposed scheme grow polynomially with the precision required.
19. Kinematic adjustments to seismic recordings
Energy Technology Data Exchange (ETDEWEB)
Telegin, A.N.; Levii, N.V.; Volovik, U.M.
1981-01-01
The introduction of kinematic adjustments by adding the displaced blocks is studied theoretically and in test seismograms. The advantage to this method resulting from the weight variation in the trace is demonstrated together with its kinematic drawback. A variation on the displaced block addition method that does not involve realignment of the travel time curves and that has improved amplitude characteristics is proposed.
20. Biquaternions and relativistic kinematics
International Nuclear Information System (INIS)
Bogush, A.A.; Kurochkin, Yu.A.; Fedorov, F.I.
1979-01-01
The problems concerning the use of quaternion interpretation of the Lorentz group vector parametrization are considered for solving relativistic kinematics problems. A vector theory convenient for describing the characteristic features of the Lobachevsky space is suggested. The kinematics of elementary particle scattering is investigated on the basis of this theory. A synthesis of vector parametrization and of quaternion calculation has been shown to lead to natural formulation of the theory of vectors in the three-dimensional Lobachevsky space, realized on mass hyperboloids of relativistic particles
1. Kinematics and dynamics of a six-degree-of-freedom robot manipulator with closed kinematic chain mechanism
Science.gov (United States)
Nguyen, Charles C.; Pooran, Farhad J.
1989-01-01
This paper deals with a class of robot manipulators built based on the kinematic chain mechanism (CKCM). This class of CKCM manipulators consists of a fixed and a moving platform coupled together via a number of in-parallel actuators. A closed-form solution is derived for the inverse kinematic problem of a six-degre-of-freedom CKCM manipulator designed to study robotic applications in space. Iterative Newton-Raphson method is employed to solve the forward kinematic problem. Dynamics of the above manipulator is derived using the Lagrangian approach. Computer simulation of the dynamical equations shows that the actuating forces are strongly dependent on the mass and centroid of the robot links.
2. Kinematic analysis for the implementation of landslide mitigation measures
Science.gov (United States)
Delmonaco, Giuseppe; Margottini, Claudio; Spizzichino, Daniele
2010-05-01
The present work is finalised at the implementation of a landslide risk mitigation master plan of the ancient citadel of Machu Picchu. After the warning launched in March 2001, by the scientific community on potential collapse of the citadel from a near-disastrous landslide event different studies have been promoted to reconstruct landslide activity and suggest landslide risk mitigation measures for the protection and conservation of Machu Picchu cultural heritage. A site-scale analysis has been implemented following the application and integration of geomechanical classifications, ambient noise measurements and structural and kinematical analysis. The geology of the area is characterized by granitoid bodies that had been emplaced in the axial zones of the main rift system that are now exposed at the highest altitudes, together with country rocks (Precambrian and Lower Paleozoic metamorphics) originally constituting the rift ‘roots'. The bedrock of the Inca citadel of Machu Picchu is mainly composed by granite and subordinately granodiorite. This is mainly located in the lower part of the slopes. Superficially, the granite is jointed in blocks with variable dimensions, promoted by local structural setting. Single blocks vary from 10-1 to about 200 m3. Soil cover, widely outcropping in the area, is mainly composed by individual blocks and subordinately by coarse materials originated by chemical and physical weathering of minerals. Regional tectonic uplift and structural setting rule the general morphological features of the area and as a consequence, landslide type and evolution. Rock falls, rock slides, debris flows and debris slides are the main landslide typologies affecting the citadel slopes. In the last mission in May 2009, elastic and deformation rock parameters have been collected using a passive seismic innovative technique based on natural microtremor measurements and geostructural scan lines elaboration. A landslide zoning of the citadel has been
3. GNSS Precise Kinematic Positioning for Multiple Kinematic Stations Based on A Priori Distance Constraints
Science.gov (United States)
He, Kaifei; Xu, Tianhe; Förste, Christoph; Petrovic, Svetozar; Barthelmes, Franz; Jiang, Nan; Flechtner, Frank
2016-01-01
When applying the Global Navigation Satellite System (GNSS) for precise kinematic positioning in airborne and shipborne gravimetry, multiple GNSS receiving equipment is often fixed mounted on the kinematic platform carrying the gravimetry instrumentation. Thus, the distances among these GNSS antennas are known and invariant. This information can be used to improve the accuracy and reliability of the state estimates. For this purpose, the known distances between the antennas are applied as a priori constraints within the state parameters adjustment. These constraints are introduced in such a way that their accuracy is taken into account. To test this approach, GNSS data of a Baltic Sea shipborne gravimetric campaign have been used. The results of our study show that an application of distance constraints improves the accuracy of the GNSS kinematic positioning, for example, by about 4 mm for the radial component. PMID:27043580
4. The high-ion content and kinematics of low-redshift Lyman limit systems
International Nuclear Information System (INIS)
Fox, Andrew J.; Tumlinson, Jason; Bordoloi, Rongmon; Lehner, Nicolas; Howk, J. Christopher; Tripp, Todd M.; Katz, Neal; Prochaska, J. Xavier; Werk, Jessica K.; O'Meara, John M.; Oppenheimer, Benjamin D.; Davé, Romeel
2013-01-01
We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distribution. Here we extend that analysis to search for differences between the high-ion and kinematic properties of the metal-poor and metal-rich branches. We find that metal-rich LLSs tend to show higher O VI columns and broader O VI profiles than metal-poor LLSs. The total H I line width (Δv 90 statistic) in LLSs is not correlated with metallicity, indicating that the H I kinematics alone cannot be used to distinguish inflow from outflow and gas recycling. Among the 17 LLSs with O VI detections, all but two show evidence of kinematic sub-structure, in the form of O VI-H I centroid offsets, multiple components, or both. Using various scenarios for how the metallicities in the high-ion and low-ion phases of each LLS compare, we constrain the ionized hydrogen column in the O VI phase to lie in the range log N(H II) ∼ 17.6-20. The O VI phase of LLSs is a substantial baryon reservoir, with M(high-ion) ∼ 10 8.5-10.9 (r/150 kpc) 2 M ☉ , similar to the mass in the low-ion phase. Accounting for the O VI phase approximately doubles the contribution of low-z LLSs to the cosmic baryon budget.
5. The high-ion content and kinematics of low-redshift Lyman limit systems
Energy Technology Data Exchange (ETDEWEB)
Fox, Andrew J.; Tumlinson, Jason; Bordoloi, Rongmon [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lehner, Nicolas; Howk, J. Christopher [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Tripp, Todd M.; Katz, Neal [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Prochaska, J. Xavier; Werk, Jessica K. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); O' Meara, John M. [Department of Physics, Saint Michael' s College, One Winooski Park, Colchester, VT 05439 (United States); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Davé, Romeel, E-mail: afox@stsci.edu [University of the Western Cape, Robert Sobukwe Road, Bellville 7535 (South Africa)
2013-12-01
We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distribution. Here we extend that analysis to search for differences between the high-ion and kinematic properties of the metal-poor and metal-rich branches. We find that metal-rich LLSs tend to show higher O VI columns and broader O VI profiles than metal-poor LLSs. The total H I line width (Δv {sub 90} statistic) in LLSs is not correlated with metallicity, indicating that the H I kinematics alone cannot be used to distinguish inflow from outflow and gas recycling. Among the 17 LLSs with O VI detections, all but two show evidence of kinematic sub-structure, in the form of O VI-H I centroid offsets, multiple components, or both. Using various scenarios for how the metallicities in the high-ion and low-ion phases of each LLS compare, we constrain the ionized hydrogen column in the O VI phase to lie in the range log N(H II) ∼ 17.6-20. The O VI phase of LLSs is a substantial baryon reservoir, with M(high-ion) ∼ 10{sup 8.5-10.9} (r/150 kpc){sup 2} M {sub ☉}, similar to the mass in the low-ion phase. Accounting for the O VI phase approximately doubles the contribution of low-z LLSs to the cosmic baryon budget.
6. Analytic structure of the n=7 scattering amplitude in N=4 SYM theory at multi-Regge kinematics. Conformal Regge pole contribution
Energy Technology Data Exchange (ETDEWEB)
Bartels, Jochen; Kormilitzin, Andrey [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Lipatov, Lev [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; St. Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation)
2013-11-15
We investigate the analytic structure of the 2 {yields} 5 scattering amplitude in the planar limit of N=4 SYM in multi-Regge kinematics in all physical regions. We demonstrate the close connection between Regge pole and Regge cut contributions: in a selected class of kinematic regions (Mandelstam regions) the usual factorizing Regge pole formula develops unphysical singularities which have to be absorbed and compensated by Regge cut contributions. This leads, in the corrections to the BDS formula, to conformal invariant 'renormalized' Regge pole expressions in the remainder function. We compute these renormalized Regge poles for the 2 {yields} 5 scattering amplitude.
7. The Size of Narrow Line Region and [OIII] Luminosity Analyzed from ...
Indian Academy of Sciences (India)
Abstract. In this work, we constructed a sample of 4002 quasars from. SDSS DR7 quasar catalogue to calculate the electron density and size of narrow line region. We find that the electron densities are ∼103/cm3, and the sizes are between 27 and 775 pc. We also find that, in the ionization cone, the sizes are tightly ...
8. Properties of kinematic singularities
Energy Technology Data Exchange (ETDEWEB)
Coley, A A [Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia B3H 3J5 (Canada); Hervik, S [Department of Mathematics and Natural Sciences, University of Stavanger, N-4036 Stavanger (Norway); Lim, W C [Albert-Einstein-Institut, Am Muehlenberg 1, D-14476 Potsdam (Germany); MacCallum, M A H, E-mail: aac@mathstat.dal.c, E-mail: sigbjorn.hervik@uis.n, E-mail: wclim@aei.mpg.d, E-mail: m.a.h.maccallum@qmul.ac.u [School of Mathematical Sciences, Queen Mary University of London, E1 4NS (United Kingdom)
2009-11-07
The locally rotationally symmetric tilted perfect fluid Bianchi type V cosmological model provides examples of future geodesically complete spacetimes that admit a 'kinematic singularity' at which the fluid congruence is inextendible but all frame components of the Weyl and Ricci tensors remain bounded. We show that for any positive integer n there are examples of Bianchi type V spacetimes admitting a kinematic singularity such that the covariant derivatives of the Weyl and Ricci tensors up to the nth order also stay bounded. We briefly discuss singularities in classical spacetimes.
9. Elemental Abundances in the Broad Emission Line Region of Quasars at Redshifts larger than 4
DEFF Research Database (Denmark)
Dietrich, M.; Appenzeller, I.; Hamann, F.
2003-01-01
the chemical composition of the line emitting gas. Comparisons to photoionization calculations indicate gas metallicities in the broad emission line region in the range of solar to several times solar. The average of the mean metallicity of each high-z quasar in this sample is $Z/Z_\\odot = 4.3 \\pm 0... 10. Kinematic Chains in Ski Jumping In-run Posture. Science.gov (United States) Janurová, Eva; Janura, Miroslav; Cabell, Lee; Svoboda, Zdeněk; Vařeka, Ivan; Elfmark, Milan 2013-12-18 The concept of kinematic chains has been systematically applied to biological systems since the 1950s. The course of a ski jump can be characterized as a change between closed and open kinematic chains. The purpose of this study was to determine a relationship between adjacent segments within the ski jumper's body's kinematic chain during the in-run phase of the ski jump. The in-run positions of 267 elite male ski jumpers who participated in the FIS World Cup events in Innsbruck, Austria, between 1992 and 2001 were analyzed (656 jumps). Two-dimensional (2-D) kinematic data were collected from the bodies of the subjects. Relationships between adjacent segments of the kinematic chain in the ski jumper's body at the in-run position are greater nearer the chain's ground contact. The coefficient of determination between the ankle and knee joint angles is 0.67. Changes in the segments' positions in the kinematic chain of the ski jumper's body are stable during longitudinal assessment. Changes in shank and thigh positions, in the sense of increase or decrease, are the same. 11. Kinematically Optimal Robust Control of Redundant Manipulators Science.gov (United States) Galicki, M. 2017-12-01 This work deals with the problem of the robust optimal task space trajectory tracking subject to finite-time convergence. Kinematic and dynamic equations of a redundant manipulator are assumed to be uncertain. Moreover, globally unbounded disturbances are allowed to act on the manipulator when tracking the trajectory by the endeffector. Furthermore, the movement is to be accomplished in such a way as to minimize both the manipulator torques and their oscillations thus eliminating the potential robot vibrations. Based on suitably defined task space non-singular terminal sliding vector variable and the Lyapunov stability theory, we derive a class of chattering-free robust kinematically optimal controllers, based on the estimation of transpose Jacobian, which seem to be effective in counteracting both uncertain kinematics and dynamics, unbounded disturbances and (possible) kinematic and/or algorithmic singularities met on the robot trajectory. The numerical simulations carried out for a redundant manipulator of a SCARA type consisting of the three revolute kinematic pairs and operating in a two-dimensional task space, illustrate performance of the proposed controllers as well as comparisons with other well known control schemes. 12. Marketing plan for Pharmacare product line in the Moscow region Case Oriola-KD OpenAIRE Mashkilleyson, Peter 2012-01-01 The thesis was commissioned by Oriola-KD. It deals with a marketing plan for a product line called Pharmacare. The product line will be launched in 2012 in the Moscow region in the Russian Federation. The purpose of this thesis was to acquire useful information about the Moscow market for the target company and produce a marketing plan that they can implement. The research question was how to create an effective marketing plan and what it entails. The literary review consisted of the theo... 13. Wave kinematics and response of slender offshore structures. Vol 4: Wave kinematics Energy Technology Data Exchange (ETDEWEB) Riber, H.J. 1999-08-01 The kinematics of large surface waves has been measured by means of sonar's placed on the sea floor at the Tyra field. Measurements from the most severe storm are analysed and extreme wave velocity profiles are compared to Stoke wave velocity profiles. Statistical distributions of crest velocity and wave celerity are presented. The analysis shows how the deviation from the Stokes prediction varies with wave heights and steepness. Analyses of the directional wave field leads to the conclusion that the extreme waves are three-dimensional. It is shown that the peculiar kinematics of extreme waves is of great relevance to the design of jacket type structures. (au) 14. Inverse kinematics of OWI-535 robotic arm OpenAIRE DEBENEC, PRIMOŽ 2015-01-01 The thesis aims to calculate the inverse kinematics for the OWI-535 robotic arm. The calculation of the inverse kinematics determines the joint parameters that provide the right pose of the end effector. The pose consists of the position and orientation, however, we will focus only on the second one. Due to arm limitations, we have created our own type of the calculation of the inverse kinematics. At first we have derived it only theoretically, and then we have transferred the derivation into... 15. Expressions of manipulator kinematic equations via symbolic computation International Nuclear Information System (INIS) Sasaki, Shinobu 1993-09-01 While it is simple in principle to determine the position and orientation of the manipulator hand, its computational process has been regarded as extremely laborious since trigonometric functions must be calculated many times in operations of revolute or rotation. Due to development of a general class of kinematic algorithm based on iterative methods, however, we have come to a satisfactory settlement of this problem. In the present article, we consider to construct symbolic kinematic equations in an automatic fashion making use of the algorithm. To this end, recursive expressions are applied to a symbolic computation system REDUCE. As a concrete result, a complete kinematic model for a six-jointed arm having all kinematic attributes is provided. Together with work space analysis, the computer-aided generation of kinematic equations in symbolic form will serve to liberate us from their cumbersome derivations. (author) 16. 2nd Conference on Interdisciplinary Applications in Kinematics CERN Document Server Flores, Francisco 2015-01-01 This book collects a number of important contributions presented during the Second Conference on Interdisciplinary Applications of Kinematics (IAK 2013) held in Lima, Peru. The conference brought together scientists from several research fields, such as computational kinematics, multibody systems, industrial machines, robotics, biomechanics, mechatronics, computational chemistry, and vibration analysis, and embraced all key aspects of kinematics, namely, theoretical methods, modeling, optimization, experimental validation, industrial applications, and design. Kinematics is an exciting area of computational mechanics and plays a central role in a great variety of fields and industrial applications nowadays. Apart from research in pure kinematics, the field deals with problems of practical relevance that need to be solved in an interdisciplinary manner in order for new technologies to develop. The results presented in this book should be of interest for practicing and research engineers as well as Ph.D. stud... 17. Fingerprinting of cell lines by directed amplification of minisatellite-region DNA (DAMD Directory of Open Access Journals (Sweden) Silva L.M. 2001-01-01 Full Text Available The development of in vitro propagation of cells has been an extraordinary technical advance for several biological studies. The correct identification of the cell line used, however, is crucial, as a mistaken identity or the presence of another contaminating cell may lead to invalid and/or erroneous conclusions. We report here the application of a DNA fingerprinting procedure (directed amplification of minisatellite-region DNA, developed by Heath et al. [Nucleic Acids Research (1993 21: 5782-5785], to the characterization of cell lines. Genomic DNA of cells in culture was extracted and amplified by PCR in the presence of VNTR core sequences, and the amplicons were separated by agarose gel electrophoresis. After image capture with a digital camera, the banding profiles obtained were analyzed using a software (AnaGel specially developed for the storage and analysis of electrophoretic fingerprints. The fingerprints are useful for construction of a data base for identification of cell lines by comparison to reference profiles as well as comparison of similar lines from different sources and periodic follow-up of cells in culture. 18. THE H I CHRONICLES OF LITTLE THINGS BCDs: EVIDENCE FOR EXTERNAL PERTURBATIONS IN THE MORPHOLOGY AND KINEMATICS OF HARO 29 AND HARO 36 International Nuclear Information System (INIS) Ashley, Trisha; Simpson, Caroline E.; Elmegreen, Bruce G. 2013-01-01 We analyze high angular and velocity resolution H I line data of two LITTLE THINGS blue compact dwarfs (BCDs): Haro 29 and Haro 36. Both of these BCDs are disturbed morphologically and kinematically. Haro 29's H I data reveal a kinematic major axis that is offset from the optical major axis, and a disturbed outer H I component, indicating that Haro 29 may have had a past interaction. Position-velocity diagrams of Haro 36 indicate that it has two kinematically separate components at its center and a likely tidal tail in front of the galaxy. We find that Haro 36 most likely had an interaction in the past, is currently interacting with an unknown companion, or is a merger remnant 19. Kinematic Identification of Parallel Mechanisms by a Divide and Conquer Strategy DEFF Research Database (Denmark) Durango, Sebastian; Restrepo, David; Ruiz, Oscar 2010-01-01 using the inverse calibration method. The identification poses are selected optimizing the observability of the kinematic parameters from a Jacobian identification matrix. With respect to traditional identification methods the main advantages of the proposed Divide and Conquer kinematic identification...... strategy are: (i) reduction of the kinematic identification computational costs, (ii) improvement of the numerical efficiency of the kinematic identification algorithm and, (iii) improvement of the kinematic identification results. The contributions of the paper are: (i) The formalization of the inverse...... calibration method as the Divide and Conquer strategy for the kinematic identification of parallel symmetrical mechanisms and, (ii) a new kinematic identification protocol based on the Divide and Conquer strategy. As an application of the proposed kinematic identification protocol the identification... 20. Development of Calculation Algorithm for ECCS Kinematic Shock Energy Technology Data Exchange (ETDEWEB) Lee, Seung-Chan; Yoon, Duk-Joo; Ha, Sang-Jun [KHNP-CRI, Daejeon (Korea, Republic of) 2014-10-15 The void fraction of inverted U-pipes in front of SI(Safety Injection) pumps impact on the pipe system of ECCS(Emergency Core Cooling Systems). This phenomena is called as 'Kinematic Shock'. The purpose of this paper is to achieve the more exactly calculation when the kinematic shock is calculated by simplified equation. The behavior of the void packet of the ECCS pipes is illustrated by the simplified (other name is kinematic shock equation).. The kinematic shock is defined as the depth of total length of void clusters in the pipes of ECCS when the void cluster is continually reached along the part of pipes in vertical direction. In this paper, the simplified equation is evaluated by comparing calculation error each other.]. The more exact methods of calculating the depth of the kinematic shock in ECCS is achieved. The error of kinematic shock calculation is strongly depended on the calculation search gap and the order of Taylor's expansion. From this study, to select the suitable search gap and the suitable calculation order, differential root method, secant method, and Taylor's expansion form are compared one another. 1. 21st Century Kinematics : The 2012 NSF Workshop CERN Document Server 2013-01-01 21st Century Kinematics focuses on algebraic problems in the analysis and synthesis of mechanisms and robots, compliant mechanisms, cable-driven systems and protein kinematics. The specialist contributors provide the background for a series of presentations at the 2012 NSF Workshop. The text shows how the analysis and design of innovative mechanical systems yield increasingly complex systems of polynomials, characteristic of those systems. In doing so, takes advantage of increasingly sophisticated computational tools developed for numerical algebraic geometry and demonstrates the now routine derivation of polynomial systems dwarfing the landmark problems of even the recent past. The 21st Century Kinematics workshop echoes the NSF-supported 1963 Yale Mechanisms Teachers Conference that taught a generation of university educators the fundamental principles of kinematic theory. As such these proceedings will be provide admirable supporting theory for a graduate course in modern kinematics and should be of consid... 2. Study of NH3 Line Intensities in the THz and Far-IR Region Science.gov (United States) Yu, Shanshan Ammonia (NH3) exists in the interstellar medium, late-type stars and giant planets of our solar system. Its temperature and abundance profiles in these environments, which are derived with its line parameters as fixed input , are commonly used to provide constraints on retrieving minor species. Therefore NH3 line parameters are essential for interpreting astrophysical and planetary spectra from Herschel, SOFIA, ALMA and JWST. However, our work under a predecessor grant with the APRA program revealed significant deficiencies in NH3 intensities in the terahertz and FIR region, including some weak Delta(K)=3 forbidden transitions predicted to be 100 times stronger. The Delta(K)=3 transitions are the ones connecting levels with different K values and therefore the only way other than collisions and l-doubled states to excite NH3 to K>0 levels. Their intensities have to be corrected to explain the observed high K excitation, such as the detection of NH3 (J,K) = (1,1), (2,2)&(14,14) and (18,18) transitions toward the galactic center star forming region Sgr B2, and to provide insights into the radiative- transfer vs. collision excitation mechanics of interstellar NH3. This proposal will remedy the serious deficiencies in the current databases involving NH3 line parameters in the terahertz and FIR region. We will target transitions with intensities greater than 10^{-23} cm-1/ (molecule/cm2) at 296 K, which will be among new astrophysical detections made by SOFIA, ALMA and JWST, and are 1000 times weaker than the strongest ground state transitions. We will retrieve new positions and intensities from existing laboratory spectra, use them to evaluate the current databases and ab initio calculations, and repair the line positions and intensities by replacing poorly calculated values with our new measurements. The proposed research will result in (1) a validated linelist containing the positions, intensities and lower state energies for the very important Delta(K)=3 NH3 FIR 3. Static and kinematic formulation of planar reciprocal assemblies DEFF Research Database (Denmark) Parigi, Dario; Sassone, Mario; Kirkegaard, Poul Henning 2014-01-01 Planar reciprocal frames are two dimensional structures formed by elements joined together according to the principle of structural reciprocity. In this paper a rigorous formulation of the static and kinematic problem is proposed and developed extending the theory of pin-jointed assemblies....... This formulation is used to evaluate the static and kinematic determinacy of reciprocal assemblies from the properties of their equilibrium and kinematic matrices... 4. Genome-wide characterization of genetic variants and putative regions under selection in meat and egg-type chicken lines. Science.gov (United States) Boschiero, Clarissa; Moreira, Gabriel Costa Monteiro; Gheyas, Almas Ara; Godoy, Thaís Fernanda; Gasparin, Gustavo; Mariani, Pilar Drummond Sampaio Corrêa; Paduan, Marcela; Cesar, Aline Silva Mello; Ledur, Mônica Corrêa; Coutinho, Luiz Lehmann 2018-01-25 Meat and egg-type chickens have been selected for several generations for different traits. Artificial and natural selection for different phenotypes can change frequency of genetic variants, leaving particular genomic footprints throghtout the genome. Thus, the aims of this study were to sequence 28 chickens from two Brazilian lines (meat and white egg-type) and use this information to characterize genome-wide genetic variations, identify putative regions under selection using Fst method, and find putative pathways under selection. A total of 13.93 million SNPs and 1.36 million INDELs were identified, with more variants detected from the broiler (meat-type) line. Although most were located in non-coding regions, we identified 7255 intolerant non-synonymous SNPs, 512 stopgain/loss SNPs, 1381 frameshift and 1094 non-frameshift INDELs that may alter protein functions. Genes harboring intolerant non-synonymous SNPs affected metabolic pathways related mainly to reproduction and endocrine systems in the white-egg layer line, and lipid metabolism and metabolic diseases in the broiler line. Fst analysis in sliding windows, using SNPs and INDELs separately, identified over 300 putative regions of selection overlapping with more than 250 genes. For the first time in chicken, INDEL variants were considered for selection signature analysis, showing high level of correlation in results between SNP and INDEL data. The putative regions of selection signatures revealed interesting candidate genes and pathways related to important phenotypic traits in chicken, such as lipid metabolism, growth, reproduction, and cardiac development. In this study, Fst method was applied to identify high confidence putative regions under selection, providing novel insights into selection footprints that can help elucidate the functional mechanisms underlying different phenotypic traits relevant to meat and egg-type chicken lines. In addition, we generated a large catalog of line-specific and common 5. Probing the accretion flow and emission-line regions of M81, the nearest broad-lined low-luminosity AGN Science.gov (United States) Barth, Aaron 2017-08-01 The nucleus of M81 is an object of singular importance as a template for low-luminosity accretion flows onto supermassive black holes. We propose to obtain a complete, small-aperture, high S/N STIS UV/optical spectrum of the M81 nucleus and multi-filter WFC3 imaging covering the UV through near-IR. Such data have never previously been obtained with HST; the only prior archival UV/optical spectra of M81 have low S/N, incomplete wavelength coverage, and are strongly contaminated by starlight. Combined with new Chandra X-ray data, our proposed observations will comprise the definitive reference dataset on the spectral energy distribution of this benchmark low-luminosity AGN. These data will provide unique new constraints on the possible contribution of a truncated thin accretion disk to the AGN emission spectrum, clarifying a fundamental property of low-luminosity accretion flows. The data will additionally provide new insights into broad-line region structure and black hole mass scaling relationships at the lowest AGN luminosities, and spatially resolved diagnostics of narrow-line region excitation conditions at unprecedented spatial resolution to assess the impact of the AGN on the ionization state of the gas in the host galaxy bulge. 6. Kinematic control of robot with degenerate wrist Science.gov (United States) Barker, L. K.; Moore, M. C. 1984-01-01 Kinematic resolved rate equations allow an operator with visual feedback to dynamically control a robot hand. When the robot wrist is degenerate, the computed joint angle rates exceed operational limits, and unwanted hand movements can result. The generalized matrix inverse solution can also produce unwanted responses. A method is introduced to control the robot hand in the region of the degenerate robot wrist. The method uses a coordinated movement of the first and third joints of the robot wrist to locate the second wrist joint axis for movement of the robot hand in the commanded direction. The method does not entail infinite joint angle rates. 7. Simple Kinematic Pathway Approach (KPA) to Catchment-scale Travel Time and Water Age Distributions Science.gov (United States) Soltani, S. S.; Cvetkovic, V.; Destouni, G. 2017-12-01 The distribution of catchment-scale water travel times is strongly influenced by morphological dispersion and is partitioned between hillslope and larger, regional scales. We explore whether hillslope travel times are predictable using a simple semi-analytical "kinematic pathway approach" (KPA) that accounts for dispersion on two levels of morphological and macro-dispersion. The study gives new insights to shallow (hillslope) and deep (regional) groundwater travel times by comparing numerical simulations of travel time distributions, referred to as "dynamic model", with corresponding KPA computations for three different real catchment case studies in Sweden. KPA uses basic structural and hydrological data to compute transient water travel time (forward mode) and age (backward mode) distributions at the catchment outlet. Longitudinal and morphological dispersion components are reflected in KPA computations by assuming an effective Peclet number and topographically driven pathway length distributions, respectively. Numerical simulations of advective travel times are obtained by means of particle tracking using the fully-integrated flow model MIKE SHE. The comparison of computed cumulative distribution functions of travel times shows significant influence of morphological dispersion and groundwater recharge rate on the compatibility of the "kinematic pathway" and "dynamic" models. Zones of high recharge rate in "dynamic" models are associated with topographically driven groundwater flow paths to adjacent discharge zones, e.g. rivers and lakes, through relatively shallow pathway compartments. These zones exhibit more compatible behavior between "dynamic" and "kinematic pathway" models than the zones of low recharge rate. Interestingly, the travel time distributions of hillslope compartments remain almost unchanged with increasing recharge rates in the "dynamic" models. This robust "dynamic" model behavior suggests that flow path lengths and travel times in shallow 8. 3-D subduction dynamics in the western Pacific: Mantle pressure, plate kinematics, and dynamic topography. Science.gov (United States) Holt, A. F.; Royden, L.; Becker, T. W.; Faccenna, C. 2017-12-01 While it is well established that the slab pull of negatively buoyant oceanic plates is the primary driving force of plate tectonics, the dynamic "details" of subduction have proved difficult to pin down. We use the Philippine Sea Plate region of the western Pacific as a site to explore links between kinematic observables (e.g. topography and plate motions) and the dynamics of the subduction system (e.g. mantle flow, mantle pressure). To first order, the Philippine Sea Plate can be considered to be the central plate of a double slab system containing two slabs that dip in the same direction, to the west. This subduction configuration presents the opportunity to explore subduction dynamics in a setting where two closely spaced slabs interact via subduction-induced mantle flow and stresses transmitted through the intervening plate. We use a 3-D numerical approach (e.g. Holt et al., 2017), augmented by semi-analytical models (e.g. Jagoutz et al., 2017), to develop relationships between dynamic processes and kinematic properties, including plate velocities, lithospheric stress state, slab dip angles, and topography. When combined with subduction zone observables, this allows us to isolate the first order dynamic processes that are in operation in the Philippine Sea Plate region. Our results suggest that positive pressure build-up occurs in the asthenosphere between the two slabs (Izu-Bonin-Mariana and Ryukyu-Nankai), and that this is responsible for producing much of the observed kinematic variability in the region, including the steep dip of the Pacific slab at the Izu-Bonin-Mariana trench, as compared to the flat dip of the Pacific slab north of Japan. We then extend our understanding of the role of asthenospheric pressure to examine the forces responsible for the plate kinematics and dynamic topography of the entire Western Pacific subduction margin(s). References:Holt, A. F., Royden, L. H., Becker, T. W., 2017. Geophys. J. Int., 209, 250-265Jagoutz, O., Royden, L 9. Kinematic equations for resolved-rate control of an industrial robot arm Science.gov (United States) Barker, L. K. 1983-01-01 An operator can use kinematic, resolved-rate equations to dynamically control a robot arm by watching its response to commanded inputs. Known resolved-rate equations for the control of a particular six-degree-of-freedom industrial robot arm and proceeds to simplify the equations for faster computations are derived. Methods for controlling the robot arm in regions which normally cause mathematical singularities in the resolved-rate equations are discussed. 10. Singular surfaces in the open field line region of a diverted tokamak International Nuclear Information System (INIS) Reiman, A. 1996-01-01 The structure of the open field lines of a slightly nonaxisymmetric, poloidally diverted tokamak is explored by numerical integration of the field line equations for a simple model field. In practice, the nonaxisymmetry could be produced self-consistently by the nonlinear evolution of a free-boundary magnetohydrodynamic (MHD) mode, or it could be produced by field errors, or it could be imposed externally by design. In the presence of a nonaxisymmetric perturbation, the tokamak is shown to develop open field line regions of differing topology separated by singular surfaces. It is argued that the singular surfaces can be expected to play a role analogous to that of rational toroidal flux surfaces, in terms of constraining ideal MHD perturbations and thus constraining the free-energy that can be tapped by ideal MHD instabilities. The possibility of active control of free-boundary instabilities by means of currents driven on the open singular surfaces, which are directly accessible from the divertor plates, is discussed. copyright 1996 American Institute of Physics 11. ANALYSIS OF CORONAL RAIN OBSERVED BY IRIS , HINODE /SOT, AND SDO /AIA: TRANSVERSE OSCILLATIONS, KINEMATICS, AND THERMAL EVOLUTION Energy Technology Data Exchange (ETDEWEB) Kohutova, P.; Verwichte, E., E-mail: p.kohutova@warwick.ac.uk [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom) 2016-08-10 Coronal rain composed of cool plasma condensations falling from coronal heights along magnetic field lines is a phenomenon occurring mainly in active region coronal loops. Recent high-resolution observations have shown that coronal rain is much more common than previously thought, suggesting its important role in the chromosphere-corona mass cycle. We present the analysis of MHD oscillations and kinematics of the coronal rain observed in chromospheric and transition region lines by the Interface Region Imaging Spectrograph (IRIS) , the Hinode Solar Optical Telescope (SOT), and the Solar Dynamics Observatory ( SDO) Atmospheric Imaging Assembly (AIA). Two different regimes of transverse oscillations traced by the rain are detected: small-scale persistent oscillations driven by a continuously operating process and localized large-scale oscillations excited by a transient mechanism. The plasma condensations are found to move with speeds ranging from few km s{sup −1} up to 180 km s{sup −1} and with accelerations largely below the free-fall rate, likely explained by pressure effects and the ponderomotive force resulting from the loop oscillations. The observed evolution of the emission in individual SDO /AIA bandpasses is found to exhibit clear signatures of a gradual cooling of the plasma at the loop top. We determine the temperature evolution of the coronal loop plasma using regularized inversion to recover the differential emission measure (DEM) and by forward modeling the emission intensities in the SDO /AIA bandpasses using a two-component synthetic DEM model. The inferred evolution of the temperature and density of the plasma near the apex is consistent with the limit cycle model and suggests the loop is going through a sequence of periodically repeating heating-condensation cycles. 12. Kinematically Decoupled Cores in Dwarf (Elliptical) Galaxies NARCIS (Netherlands) Toloba, E.; Peletier, R. F.; Guhathakurta, P.; van de Ven, G.; Boissier, S.; Boselli, A.; Brok, M. d.; Falcón-Barroso, J.; Hensler, G.; Janz, J.; Laurikainen, E.; Lisker, T.; Paudel, S.; Ryś, A.; Salo, H. An overview is given of what we know about the frequency of kinematically decoupled cores in dwarf elliptical galaxies. New observations show that kinematically decoupled cores happen just as often in dwarf elliptical as in ordinary early-type galaxies. This has important consequences for the 13. Validation and structural analysis of the kinematics concept test Directory of Open Access Journals (Sweden) A. Lichtenberger 2017-04-01 Full Text Available The kinematics concept test (KCT is a multiple-choice test designed to evaluate students’ conceptual understanding of kinematics at the high school level. The test comprises 49 multiple-choice items about velocity and acceleration, which are based on seven kinematic concepts and which make use of three different representations. In the first part of this article we describe the development and the validation process of the KCT. We applied the KCT to 338 Swiss high school students who attended traditional teaching in kinematics. We analyzed the response data to provide the psychometric properties of the test. In the second part we present the results of a structural analysis of the test. An exploratory factor analysis of 664 student answers finally uncovered the seven kinematics concepts as factors. However, the analysis revealed a hierarchical structure of concepts. At the higher level, mathematical concepts group together, and then split up into physics concepts at the lower level. Furthermore, students who seem to understand a concept in one representation have difficulties transferring the concept to similar problems in another representation. Both results have implications for teaching kinematics. First, teaching mathematical concepts beforehand might be beneficial for learning kinematics. Second, instructions have to be designed to teach students the change between different representations. 14. Validation and structural analysis of the kinematics concept test Science.gov (United States) Lichtenberger, A.; Wagner, C.; Hofer, S. I.; Stern, E.; Vaterlaus, A. 2017-06-01 The kinematics concept test (KCT) is a multiple-choice test designed to evaluate students' conceptual understanding of kinematics at the high school level. The test comprises 49 multiple-choice items about velocity and acceleration, which are based on seven kinematic concepts and which make use of three different representations. In the first part of this article we describe the development and the validation process of the KCT. We applied the KCT to 338 Swiss high school students who attended traditional teaching in kinematics. We analyzed the response data to provide the psychometric properties of the test. In the second part we present the results of a structural analysis of the test. An exploratory factor analysis of 664 student answers finally uncovered the seven kinematics concepts as factors. However, the analysis revealed a hierarchical structure of concepts. At the higher level, mathematical concepts group together, and then split up into physics concepts at the lower level. Furthermore, students who seem to understand a concept in one representation have difficulties transferring the concept to similar problems in another representation. Both results have implications for teaching kinematics. First, teaching mathematical concepts beforehand might be beneficial for learning kinematics. Second, instructions have to be designed to teach students the change between different representations. 15. Validation and Structural Analysis of the Kinematics Concept Test Science.gov (United States) Lichtenberger, A.; Wagner, C.; Hofer, S. I.; Stem, E.; Vaterlaus, A. 2017-01-01 The kinematics concept test (KCT) is a multiple-choice test designed to evaluate students' conceptual understanding of kinematics at the high school level. The test comprises 49 multiple-choice items about velocity and acceleration, which are based on seven kinematic concepts and which make use of three different representations. In the first part… 16. Differences between kinematic synergies and muscle synergies during two-digit grasping Directory of Open Access Journals (Sweden) Michele eTagliabue 2015-03-01 Full Text Available The large number of mechanical degrees of freedom of the hand is not fully exploited during actual movements such as grasping. Usually, angular movements in various joints tend to be coupled, and EMG activities in different hand muscles tend to be correlated. The occurrence of covariation in the former was termed kinematic synergies, in the latter muscle synergies. This study addresses two questions: (i Whether kinematic and muscle synergies can simultaneously accommodate for kinematic and kinetic constraints. (ii If so, whether there is an interrelation between kinematic and muscle synergies. We used a reach-grasp-and-pull paradigm and recorded the hand kinematics as well as 8 surface EMGs. Subjects had to either perform a precision grip or side grip and had to modify their grip force in order to displace an object against a low or high load. The analysis was subdivided into three epochs: reach, grasp-and-pull, and static hold. Principal component analysis (PCA, temporal or static was performed separately for all three epochs, in the kinematic and in the EMG domain. PCA revealed that (i Kinematic- and muscle-synergies can simultaneously accommodate kinematic (grip type and kinetic task constraints (load condition. (ii Upcoming grip and load conditions of the grasp are represented in kinematic- and muscle-synergies already during reach. Phase plane plots of the principal muscle-synergy against the principal kinematic synergy revealed (iii that the muscle-synergy is linked (correlated, and in phase advance to the kinematic synergy during reach and during grasp-and-pull. Furthermore (iv, pair-wise correlations of EMGs during hold suggest that muscle-synergies are (in part implemented by coactivation of muscles through common input. Together, these results suggest that kinematic synergies have (at least in part their origin not just in muscular activation, but in synergiestic muscle activation. In short: kinematic synergies may result from muscle 17. Theoretical description of spectral line profiles of parent molecules in cometary comae International Nuclear Information System (INIS) Hu, Hong-Yao; Larson, H.P.; Hsieh, K.C. 1991-01-01 The present overview of cometary spectral-line profiles obtainable through advancements in high-resolution spectroscopic studies, which allow the retrieval of coma kinematic properties from velocity-resolved spectral-line profiles, incorporates the most important gas dynamic processes into an outflow model which is tailored to the interpretation of spectroscopic observations of parent molecules. The model is then used to study the influence on parent-molecule spectral line profile formation of the field-of-view, the expansion velocity, the kinetic temperature, and the anisotropic outflow distributions. 31 refs 18. A Case Study of a Quasi-Stationary Tropical Convective Line Science.gov (United States) 1989-08-01 G Scialom, and J. Testud , 1987: A tropical squall line observed during the COPT 81 experiment in West Africa. Part 1: Kinematic structure inferred...mesosynoptic analysis of the thunderstorms on 28 August 1958. Brit. Meteor. Office, Geophys. Memo., No. 106, 74 pp. Rcux, F., J. Testud , M. Payen and B. Pinty 19. Multibody Kinematics Optimization for the Estimation of Upper and Lower Limb Human Joint Kinematics: A Systematized Methodological Review. Science.gov (United States) Begon, Mickaël; Andersen, Michael Skipper; Dumas, Raphaël 2018-03-01 Multibody kinematics optimization (MKO) aims to reduce soft tissue artefact (STA) and is a key step in musculoskeletal modeling. The objective of this review was to identify the numerical methods, their validation and performance for the estimation of the human joint kinematics using MKO. Seventy-four papers were extracted from a systematized search in five databases and cross-referencing. Model-derived kinematics were obtained using either constrained optimization or Kalman filtering to minimize the difference between measured (i.e., by skin markers, electromagnetic or inertial sensors) and model-derived positions and/or orientations. While hinge, universal, and spherical joints prevail, advanced models (e.g., parallel and four-bar mechanisms, elastic joint) have been introduced, mainly for the knee and shoulder joints. Models and methods were evaluated using: (i) simulated data based, however, on oversimplified STA and joint models; (ii) reconstruction residual errors, ranging from 4 mm to 40 mm; (iii) sensitivity analyses which highlighted the effect (up to 36 deg and 12 mm) of model geometrical parameters, joint models, and computational methods; (iv) comparison with other approaches (i.e., single body kinematics optimization and nonoptimized kinematics); (v) repeatability studies that showed low intra- and inter-observer variability; and (vi) validation against ground-truth bone kinematics (with errors between 1 deg and 22 deg for tibiofemoral rotations and between 3 deg and 10 deg for glenohumeral rotations). Moreover, MKO was applied to various movements (e.g., walking, running, arm elevation). Additional validations, especially for the upper limb, should be undertaken and we recommend a more systematic approach for the evaluation of MKO. In addition, further model development, scaling, and personalization methods are required to better estimate the secondary degrees-of-freedom (DoF). 20. Simulation and experimental research on line throwing rocket with flight OpenAIRE Wen-bin Gu; Ming Lu; Jian-qing Liu; Qin-xing Dong; Zhen-xiong Wang; Jiang-hai Chen 2014-01-01 The finite segment method is used to model the line throwing rocket system. A dynamic model of line throwing rocket with flight motion based on Kane's method is presented by the kinematics description of the system and the consideration of the forces acting on the system. The experiment designed according to the parameters of the dynamic model is made. The simulation and experiment results, such as range, velocity and flight time, are compared and analyzed. The simulation results are basicall... 1. THE STELLAR AND GAS KINEMATICS OF THE LITTLE THINGS DWARF IRREGULAR GALAXY NGC 1569 International Nuclear Information System (INIS) Johnson, Megan; Hunter, Deidre A.; Zhang, Hong-Xin; Herrmann, Kimberly; Oh, Se-Heon; Elmegreen, Bruce; Brinks, Elias; Tollerud, Erik 2012-01-01 In order to understand the formation and evolution of Magellanic-type dwarf irregular (dIm) galaxies, one needs to understand their three-dimensional structure. We present measurements of the stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy. The stellar vertical velocity dispersion, σ z , coupled with the maximum rotational velocity derived from H I observations, V max , gives a measure of how kinematically hot the galaxy is, and, therefore, indicates its structure. We conclude that the stars in NGC 1569 are in a thick disk with a V max /σ z = 2.4 ± 0.7. In addition to the structure, we analyze the ionized gas kinematics from O III observations along the morphological major axis. These data show evidence for outflow from the inner starburst region and a potential expanding shell near supermassive star cluster (SSC) A. When compared to the stellar kinematics, the velocity dispersion of the stars increases in the region of SSC A supporting the hypothesis of an expanding shell. The stellar kinematics closely follow the motion of the gas. Analysis of high-resolution H I data clearly reveals the presence of an H I cloud that appears to be impacting the eastern edge of NGC 1569. Also, an ultra-dense H I cloud can be seen extending to the west of the impacting H I cloud. This dense cloud is likely the remains of a dense H I bridge that extended through what is now the central starburst area. The impacting H I cloud was the catalyst for the starburst, thus turning the dense gas into stars over a short timescale, ∼1 Gyr. We performed a careful study of the spectral energy distribution using infrared, optical, and ultraviolet photometry, producing a state-of-the-art mass model for the stellar disk. This mass modeling shows that stars dominate the gravitational potential in the inner 1 kpc. The dynamical mass of NGC 1569, derived from V max , shows that the disk may be dark matter deficient in the inner region, although, when compared to the 2. Force generation of bio-inspired hover kinematics NARCIS (Netherlands) Vandenheede, R.B.R.; Bernal, L.P.; Morrison, C.L.; Humbert, S. 2012-01-01 This paper presents the results of an experimental study of the aerodynamics of an elliptical flap plate wing in pitch-plunge motion. Several wing motion kinematics are derived from the kinematics of the Agrius Convolvuli (hawk moth) in hover. The experiments are conducted at a Reynolds number of 4, 3. A Novel Algorithm for the Generation of Distinct Kinematic Chain Science.gov (United States) Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao 2016-07-01 Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom. 4. Exploring the Origin of Kinematically Irregular Galaxies with MaNGA Science.gov (United States) Stark, David Vincent; Bundy, Kevin; Westfall, Kyle; Bershady, Matthew; Cheung, Edmond; Soler, Juan; Brinchmann, Jarle; Abraham, Roberto; Bizyaev, Dmitry; Masters, Karen; Weijmans, Anne-Marie; Chen, Yanmei; Jin, Yifei; Drory, Niv; Lopes, Alexandre Roman; Law, David 2018-01-01 Deviations from normal rotation in galaxies may have a number of potential drivers, including tidal interactions, gas inflows/outflows, spiral structure, bar/oval distortions, or other internally generated instabilities. Thanks to new massive IFU surveys like MaNGA, we can now characterize the gas and stellar kinematics of thousands of galaxies in the local universe, enabling statistical analyses on the frequency of disturbed kinematics, their origin, and their impact on their host galaxies. We present a census of kinematics in MaNGA using a modified version of the Radon transform to map radial variations in kinematic position angles (PA). We discuss the frequency of kinematically irregular disks, and describe commonly observed patterns in radial PA profiles. In order to constrain the drivers of these kinematic signatures, we analyze how they correlate with galaxy mass, environment, star formation history, and gas-phase metallicity. 5. Modeling neutrino-induced charged pion production on water at T2K kinematics Science.gov (United States) Nikolakopoulos, A.; González-Jiménez, R.; Niewczas, K.; Sobczyk, J.; Jachowicz, N. 2018-05-01 Pion production is a significant component of the signal in accelerator-based neutrino experiments. Over the last years, the MiniBooNE, T2K, and MINERvA collaborations have reported a substantial amount of data on (anti)neutrino-induced pion production on the nucleus. However, a comprehensive and consistent description of the whole data set is still missing. We aim at improving the current understanding of neutrino-induced pion production on the nucleus. To this end, the comparison of experimental data with theoretical predictions, preferably based on microscopic models, is essential to disentangle the different reaction mechanisms involved in the process. To describe single-pion production, we use a hybrid model that combines low- and a high-energy approaches. The low-energy model contains resonances and background terms. At high invariant masses, a high-energy model based on a Regge approach is employed. The model is implemented in the nucleus using the relativistic plane wave impulse approximation (RPWIA). We present a comparison of the hybrid-RPWIA and low-energy model with the recent neutrino-induced charged-current 1 π+ -production cross section on water reported by T2K. In order to judge the impact of final-state interactions (FSI), we confront our results with those of the nuwro Monte Carlo generator. The hybrid-RPWIA model and nuwro results compare favorably to the data, albeit that FSI are not included in the former. The need of a high-energy model at T2K kinematics is made clear. These results complement our previous work [Phys. Rev. D 97, 013004 (2018), 10.1103/PhysRevD.97.013004], in which we compared the models to the MINERvA and MiniBooNE 1 π+ data. The hybrid-RPWIA model tends to overpredict both the T2K and MINERvA data in kinematic regions where the largest suppression due to FSI is expected and agrees remarkably well with the data in other kinematic regions. On the contrary, the MiniBooNE data are underpredicted over the whole kinematic range. 6. Internal Stellar Kinematics of M32 from the SPLASH Survey: Dark Halo Constraints Science.gov (United States) Howley, K. M.; Guhathakurta, P.; van der Marel, R.; Geha, M.; Kalirai, J.; Yniguez, B.; Kirby, E.; Cuillandre, J.-C.; Gilbert, K. 2013-03-01 As part of the SPLASH survey of the Andromeda (M31) system, we have obtained Keck/DEIMOS spectra of the compact elliptical (cE) satellite M32. This is the first resolved-star kinematical study of any cE galaxy. In contrast to most previous kinematical studies that extended out to r information to account statistically for M31 contamination. The rotation curve and velocity dispersion profile extend well beyond the radius (r ~ 150'') where the isophotes are distorted. Unlike NGC 205, another close dwarf companion of M31, M32's kinematics appear regular and symmetric and do not show obvious sharp gradients across the region of isophotal elongation and twists. We interpret M31's kinematics using three-integral axisymmetric dynamical equilibrium models constructed using Schwarzschild's orbit superposition technique. Models with a constant mass-to-light ratio can fit the data remarkably well. However, since such a model requires an increasing tangential anisotropy with radius, invoking the presence of an extended dark halo may be more plausible. Such an extended dark halo is definitely required to bind a half-dozen fast-moving stars observed at the largest radii, but these stars may not be an equilibrium component of M32. Data herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. 7. Chiral quark model with relativistic kinematics International Nuclear Information System (INIS) Garcilazo, H.; Valcarce, A. 2003-01-01 The nonstrange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the σ meson) leads to an overall good description of the spectrum 8. Chiral quark model with relativistic kinematics OpenAIRE Garcilazo, H.; Valcarce, A. 2003-01-01 The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the$\\sigmameson) leads to an overall good description of the spectrum. 9. Plastic frames: Reduction of the kinematical inequality and optimization International Nuclear Information System (INIS) Brousse, P. 1979-01-01 It is well-known that the following inequality plays an essential part in the theory of perfectly plastic frames: for all kinematically admissible mechanisms and for bending moments associated with the hinge rotations by the flow rule, the plastic dissipation power is greater than or equal to the load power. This inequality will be termed as the kinematic inequality. It contains parameters generating the mechanisms. In simple cases, several ingenious authors obtained appreciable results excluding parameters. But, in more complicated cases, for instance when the given quantities are not numerical, the parameters remain in the kinematic inequality, thereby precluding exploitation of the kinematic approach. In the present work we overcome this dificulty: we reduce the kinematic inequality, i.e., we replace it by inequalities containing no variable parameter; we then state a process giving automatically such inequalities; finally, we treat a practical application. (orig.) 10. The Kinematic Learning Model using Video and Interfaces Analysis Science.gov (United States) Firdaus, T.; Setiawan, W.; Hamidah, I. 2017-09-01 An educator currently in demand to apply the learning to not be separated from the development of technology. Educators often experience difficulties when explaining kinematics material, this is because kinematics is one of the lessons that often relate the concept to real life. Kinematics is one of the courses of physics that explains the cause of motion of an object, Therefore it takes the thinking skills and analytical skills in understanding these symptoms. Technology is one that can bridge between conceptual relationship with real life. A framework of technology-based learning models has been developed using video and interfaces analysis on kinematics concept. By using this learning model, learners will be better able to understand the concept that is taught by the teacher. This learning model is able to improve the ability of creative thinking, analytical skills, and problem-solving skills on the concept of kinematics. 11. Development of Kinematic 3D Laser Scanning System for Indoor Mapping and As-Built BIM Using Constrained SLAM Directory of Open Access Journals (Sweden) Jaehoon Jung 2015-10-01 Full Text Available The growing interest and use of indoor mapping is driving a demand for improved data-acquisition facility, efficiency and productivity in the era of the Building Information Model (BIM. The conventional static laser scanning method suffers from some limitations on its operability in complex indoor environments, due to the presence of occlusions. Full scanning of indoor spaces without loss of information requires that surveyors change the scanner position many times, which incurs extra work for registration of each scanned point cloud. Alternatively, a kinematic 3D laser scanning system, proposed herein, uses line-feature-based Simultaneous Localization and Mapping (SLAM technique for continuous mapping. Moreover, to reduce the uncertainty of line-feature extraction, we incorporated constrained adjustment based on an assumption made with respect to typical indoor environments: that the main structures are formed of parallel or orthogonal line features. The superiority of the proposed constrained adjustment is its reduction for uncertainties of the adjusted lines, leading to successful data association process. In the present study, kinematic scanning with and without constrained adjustment were comparatively evaluated in two test sites, and the results confirmed the effectiveness of the proposed system. The accuracy of the 3D mapping result was additionally evaluated by comparison with the reference points acquired by a total station: the Euclidean average distance error was 0.034 m for the seminar room and 0.043 m for the corridor, which satisfied the error tolerance for point cloud acquisition (0.051 m according to the guidelines of the General Services Administration for BIM accuracy. 12. STAR FORMATION IN SELF-GRAVITATING DISKS IN ACTIVE GALACTIC NUCLEI. II. EPISODIC FORMATION OF BROAD-LINE REGIONS International Nuclear Information System (INIS) WangJianmin; Du Pu; Ge Junqiang; Hu Chen; Baldwin, Jack A.; Ferland, Gary J. 2012-01-01 This is the second in a series of papers discussing the process and effects of star formation in the self-gravitating disk around the supermassive black holes in active galactic nuclei (AGNs). We have previously suggested that warm skins are formed above the star-forming (SF) disk through the diffusion of warm gas driven by supernova explosions. Here we study the evolution of the warm skins when they are exposed to the powerful radiation from the inner part of the accretion disk. The skins initially are heated to the Compton temperature, forming a Compton atmosphere (CAS) whose subsequent evolution is divided into four phases. Phase I is the duration of pure accumulation supplied by the SF disk. During phase II clouds begin to form due to line cooling and sink to the SF disk. Phase III is a period of preventing clouds from sinking to the SF disk through dynamic interaction between clouds and the CAS because of the CAS overdensity driven by continuous injection of warm gas from the SF disk. Finally, phase IV is an inevitable collapse of the entire CAS through line cooling. This CAS evolution drives the episodic appearance of broad-line regions (BLRs). We follow the formation of cold clouds through the thermal instability of the CAS during phases II and III, using linear analysis. Since the clouds are produced inside the CAS, the initial spatial distribution of newly formed clouds and angular momentum naturally follow the CAS dynamics, producing a flattened disk of clouds. The number of clouds in phases II and III can be estimated, as well as the filling factor of clouds in the BLR. Since the cooling function depends on the metallicity, the metallicity gradients that originate in the SF disk give rise to different properties of clouds in different radial regions. We find from the instability analysis that clouds have column density N H ∼ 22 cm –2 in the metal-rich regions whereas they have N H ∼> 10 22 cm –2 in the metal-poor regions. The metal-rich clouds 13. Kinematics of the quaternary fault zones in the Kyeongju area of the southeastern Korean Peninsula Energy Technology Data Exchange (ETDEWEB) Kim, In Seob; Lee, Byeong Hyui; Kwon, Hyeok Sang [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)] (and others) 1998-09-15 The purposes of this study are to interpret the kinematics of the Quaternary fault zones in the Kyeongju area, to determine deformation mechanisms during faulting by analyzing micorstrucutres of fault rocks from the fault zones, and to unravel the technic evaluation of the regional fault structures in the Kyeongju-Wolsung area. The scope of this study consists of ; collection and interpretation of structural elements through a detailed geologic investigation on the Quaternary faults in the Kyeongju-Wolsung area, interpretation of fault-rock microstructures from the fault zones using oriented samples of faults rocks, determination of deformation processes and mechanisms of the fault rocks and, interpretation of faulting kinematics and evaluation of the fault zones. 14. Kinematics of the quaternary fault zones in the Kyeongju area of the southeastern Korean Peninsula International Nuclear Information System (INIS) Kim, In Seob; Lee, Byeong Hyui; Kwon, Hyeok Sang 1998-09-01 The purposes of this study are to interpret the kinematics of the Quaternary fault zones in the Kyeongju area, to determine deformation mechanisms during faulting by analyzing micorstrucutres of fault rocks from the fault zones, and to unravel the technic evaluation of the regional fault structures in the Kyeongju-Wolsung area. The scope of this study consists of ; collection and interpretation of structural elements through a detailed geologic investigation on the Quaternary faults in the Kyeongju-Wolsung area, interpretation of fault-rock microstructures from the fault zones using oriented samples of faults rocks, determination of deformation processes and mechanisms of the fault rocks and, interpretation of faulting kinematics and evaluation of the fault zones 15. Study of actinides fission induced by multi-nucleon transfer reactions in inverse kinematics International Nuclear Information System (INIS) Derkx, X. 2010-10-01 The study of actinide fission encounters two major issues. On one hand, measurements of the fission fragment distributions and the fission probabilities allow a better understanding of the fission process itself and the discrimination among the models of nuclear structure and dynamics. On the other hand, new measurements are required to improve nuclear data bases, which are a key component for the design of new generation reactors and radio-toxic waste incinerators. This thesis is in line with different French and American experimental projects using the surrogate method, i.e. transfer reactions leading to the same compound nuclei as in neutron irradiation, allowing the study of fission of actinides which are inaccessible by conventional techniques, whereas they are important for applications. The experiment is based on multi-nucleon transfer reactions between a 238 U beam and a 12 C target, using the inverse kinematics technique to measure, for each transfer channel, the complete isotopic distributions of the fission fragments with the VAMOS spectrometer. The work presented in this dissertation is focused on the identification of the transfer channels and their properties, as their angular distributions and the distributions of the associated excitation energy, using the SPIDER telescope to identify the target recoil nuclei. This work of an exploratory nature aims to generalize the surrogate method to heavy transfers and to measure, for the first time, the fission probabilities in inverse kinematics. The obtained results are compared with available direct kinematics and neutron irradiation measurements. (author) 16. Kinematic design considerations for minimally invasive surgical robots: an overview. Science.gov (United States) Kuo, Chin-Hsing; Dai, Jian S; Dasgupta, Prokar 2012-06-01 Kinematic design is a predominant phase in the design of robotic manipulators for minimally invasive surgery (MIS). However, an extensive overview of the kinematic design issues for MIS robots is not yet available to both mechanisms and robotics communities. Hundreds of archival reports and articles on robotic systems for MIS are reviewed and studied. In particular, the kinematic design considerations and mechanism development described in the literature for existing robots are focused on. The general kinematic design goals, design requirements, and design preferences for MIS robots are defined. An MIS-specialized mechanism, namely the remote center-of-motion (RCM) mechanism, is revisited and studied. Accordingly, based on the RCM mechanism types, a classification for MIS robots is provided. A comparison between eight different RCM types is given. Finally, several open challenges for the kinematic design of MIS robotic manipulators are discussed. This work provides a detailed survey of the kinematic design of MIS robots, addresses the research opportunity in MIS robots for kinematicians, and clarifies the kinematic point of view to MIS robots as a reference for the medical community. Copyright © 2012 John Wiley & Sons, Ltd. 17. Kinematic analysis of a posterior-stabilized knee prosthesis. Science.gov (United States) Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia 2015-01-20 The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion. Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, "rollback" compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis. 18. Kinematic Analysis of a Posterior-stabilized Knee Prosthesis Directory of Open Access Journals (Sweden) Zhi-Xin Zhao 2015-01-01 Full Text Available Background: The goal of total knee arthroplasty (TKA is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion. Results: Both the output data trends and the measured values derived from the normal knee′s kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, "rollback" compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis. 19. Kinematic Analysis of a Posterior-stabilized Knee Prosthesis Science.gov (United States) Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia 2015-01-01 Background: The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0–135° flexion. Results: Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, “rollback” compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis. PMID:25591565 20. Singular surfaces in the open field line region of a diverted tokamak International Nuclear Information System (INIS) Reiman, A. 1995-05-01 The structure of the open field lines of a slightly nonaxisymmetric, poloidally diverted tokamak is explored by numerical integration of the field line equations for a simple model field. In practice, the nonaxisymmetry could be produced self-consistently by the nonlinear evolution of a free-boundary MHD mode, or it could be produced by field errors, or it could be imposed externally by design. In the presence of a nonaxisymmetric perturbation, the tokamak is shown to develop open field line regions of differing topology separated by singular surfaces. It is argued that the singular surfaces can be expected to play a role analogous to that of rational toroidal flux surfaces, in terms of constraining ideal MHD perturbations and thus constraining the free-energy that can be tapped by ideal MHD instabilities. The possibility of active control of free-boundary instabilities by means of currents driven on the open singular surfaces, which are directly accessible from the divertor plates, is discussed. Also discussed is the possibility of early detection of imminent disruptions through localized measurement of the singular surface currents 1. Agent Control for Reconfigurable Open Kinematic Chain Manipulators Directory of Open Access Journals (Sweden) Janez Sluga 2013-10-01 Full Text Available This paper presents a method for the autonomous control of differently structured open kinematic chains based on multi-agent system technology. The appropriate level of distributing local autonomy (agents to a manipulative structure is defined, which makes it possible to dynamically change the number, type and structure of manipulative components without modifying their behavioural logic. To achieve fast reconfigurable and scalable manipulative systems, a new multi-agent method is developed for controlling the manipulator kinematics. The new method enables independent manipulator structure from the control system because of its structural and system modularity. The proposed method consists of kinematic equations for use in an agent environment, agent motion-planning algorithms, evaluation functions, agent control logic and kinematic algorithms. The results of simulations and real-world experiments demonstrate the usefulness of the approach for different non-redundant and redundant manipulation structures. 2. Damped least square based genetic algorithm with Gaussian distribution of damping factor for singularity-robust inverse kinematics International Nuclear Information System (INIS) Phuoc, Le Minh; Lee, Suk Han; Kim, Hun Mo; Martinet, Philippe 2008-01-01 Robot inverse kinematics based on Jacobian inversion encounters critical issues of kinematic singularities. In this paper, several techniques based on damped least squares are proposed to lead robot pass through kinematic singularities without excessive joint velocities. Unlike other work in which the same damping factor is used for all singular vectors, this paper proposes a different damping coefficient for each singular vector based on corresponding singular value of the Jacobian. Moreover, a continuous distribution of damping factor following Gaussian function guarantees the continuous in joint velocities. A genetic algorithm is utilized to search for the best maximum damping factor and singular region, which used to require ad hoc searching in other works. As a result, end effector tracking error, which is inherited from damped least squares by introducing damping factors, is minimized. The effectiveness of our approach is compared with other methods in both non-redundant robot and redundant robot 3. Damped least square based genetic algorithm with Gaussian distribution of damping factor for singularity-robust inverse kinematics Energy Technology Data Exchange (ETDEWEB) Phuoc, Le Minh; Lee, Suk Han; Kim, Hun Mo [Sungkyunkwan University, Suwon (Korea, Republic of); Martinet, Philippe [Blaise Pascal University, Clermont-Ferrand Cedex (France) 2008-07-15 Robot inverse kinematics based on Jacobian inversion encounters critical issues of kinematic singularities. In this paper, several techniques based on damped least squares are proposed to lead robot pass through kinematic singularities without excessive joint velocities. Unlike other work in which the same damping factor is used for all singular vectors, this paper proposes a different damping coefficient for each singular vector based on corresponding singular value of the Jacobian. Moreover, a continuous distribution of damping factor following Gaussian function guarantees the continuous in joint velocities. A genetic algorithm is utilized to search for the best maximum damping factor and singular region, which used to require ad hoc searching in other works. As a result, end effector tracking error, which is inherited from damped least squares by introducing damping factors, is minimized. The effectiveness of our approach is compared with other methods in both non-redundant robot and redundant robot 4. Kinematic Analysis of Continuum Robot Consisted of Driven Flexible Rods Directory of Open Access Journals (Sweden) Yingzhong Tian 2016-01-01 Full Text Available This paper presents the kinematic analysis of a continuum bionic robot with three flexible actuation rods. Since the motion of the end-effector is actuated by the deformation of the rods, the robot structure is with high elasticity and good compliance and the kinematic analysis of the robot requires special treatment. We propose a kinematic model based on the geometry with constant curvature. The analysis consists of two independent mappings: a general mapping for the kinematics of all robots and a specific mapping for this kind of robots. Both of those mappings are developed for the single section and for the multisections. We aim at providing a guide for kinematic analysis of the similar manipulators through this paper. 5. GEMINI NEAR INFRARED FIELD SPECTROGRAPH OBSERVATIONS OF THE SEYFERT 2 GALAXY MRK 573: IN SITU ACCELERATION OF IONIZED AND MOLECULAR GAS OFF FUELING FLOWS Energy Technology Data Exchange (ETDEWEB) Fischer, Travis C.; Straughn, A. N. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Machuca, C.; Crenshaw, D. M.; Baron, F.; Revalski, M.; Pope, C. L. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, 25 Park Place, Suite 605, Atlanta, GA 30303 (United States); Diniz, M. R.; Riffel, R. A. [Departamento de Física, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Kraemer, S. B. [Institute for Astrophysics and Computational Sciences, Department of Physics, The Catholic University of America, Washington, DC 20064 (United States); Schmitt, H. R. [Naval Research Laboratory, Washington, DC 20375 (United States); Storchi-Bergmann, T., E-mail: travis.c.fischer@nasa.gov [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, IF, CP 15051, 91501-970 Porto Alegre, RS (Brazil) 2017-01-01 We present near-infrared and optical emission-line and stellar kinematics of the Seyfert 2 galaxy Mrk 573 using the Near-Infrared Field Spectrograph (NIFS) at Gemini North and Dual Imaging Spectrograph at Apache Point Observatory, respectively. By obtaining full kinematic maps of the infrared ionized and molecular gas and stellar kinematics in a ∼700 × 2100 pc{sup 2} circumnuclear region of Mrk 573, we find that kinematics within the Narrow-Line Region are largely due to a combination of both rotation and in situ acceleration of material originating in the host disk. Combining these observations with large-scale, optical long-slit spectroscopy that traces ionized gas emission out to several kpcs, we find that rotation kinematics dominate the majority of the gas. We find that outflowing gas extends to distances less than 1 kpc, suggesting that outflows in Seyfert galaxies may not be powerful enough to evacuate their entire bulges. 6. Gemini Near Infrared Field Spectrograph Observations of the Seyfert 2 Galaxy MRK 573: In Situ Acceleration of Ionized and Molecular Gas Off Fueling Flows Science.gov (United States) Fischer, Travis C.; Machuca, C.; Diniz, M. R.; Crenshaw, D. M.; Kraemer, S. B.; Riffel, R. A.; Schmitt, H. R.; Baron, F.; Storchi-Bergmann, T.; Straughn, A. N.; 2016-01-01 We present near-infrared and optical emission-line and stellar kinematics of the Seyfert 2 galaxy Mrk 573 using the Near-Infrared Field Spectrograph (NIFS) at Gemini North and Dual Imaging Spectrograph at Apache Point Observatory, respectively. By obtaining full kinematic maps of the infrared ionized and molecular gas and stellar kinematics in approximately 700 x 2100 pc(exp 2) circumnuclear region of Mrk 573, we find that kinematics within the Narrow-Line Region are largely due to a combination of both rotation and in situ acceleration of material originating in the host disk. Combining these observations with large-scale, optical long-slit spectroscopy that traces ionized gas emission out to several kpcs, we find that rotation kinematics dominate the majority of the gas. We find that outflowing gas extends to distances less than 1 kpc, suggesting that outflows in Seyfert galaxies may not be powerful enough to evacuate their entire bulges. 7. International Nuclear Information System (INIS) Chemin, Laurent; Carignan, Claude; Foster, Tyler 2009-01-01 We present a new deep 21 cm survey of the Andromeda galaxy, based on high-resolution observations performed with the Synthesis Telescope and the 26 m antenna at the Dominion Radio Astrophysical Observatory. The H I distribution and kinematics of the disk are analyzed and basic dynamical properties are given. The rotation curve is measured out to 38 kpc, showing a nuclear peak at 340 km s -1 , a dip at 202 km s -1 around 4 kpc, two distinct flat parts at 264 km s -1 and 230 km s -1 , and an increase to 275 km s -1 in the outermost regions. Except for the innermost regions, the axisymmetry of the gas rotation is very good. A very strong warp of the H I disk is evidenced. The central regions appear less inclined than the average disk inclination of 74 0 , while the outer regions appear more inclined. Mass distribution models by ΛCDM Navarro-Frenk-White, Einasto or pseudo-isothermal dark matter halos with baryonic components are presented. They fail to reproduce the exact shape of the rotation curve. No significant differences are measured between the various shapes of halo. The dynamical mass of M31 enclosed within a radius of 38 kpc is (4.7 ± 0.5) x 10 11 M sun . The dark matter component is almost four times more massive than the baryonic mass inside this radius. A total mass of 1.0 x 10 12 M sun is derived inside the virial radius. The spectral structure of the observations is very complex, with sometimes up to five H I components detected per spectrum, which is very rarely seen in other galaxies. New H I structures are discovered in the datacube. The most remarkable new features are an external arm and thin H I spurs in the disk outskirts. A relationship between these spurs and outer stellar clumps is evidenced. The external arm is 32 kpc long, lies on the far side of the galaxy, and has no obvious counterpart on the other side of the galaxy. Its kinematics clearly differs from the outer adjacent disk. Both these H I perturbations could result from tidal 8. Shoulder and Scapular Kinematics during the Windmill Softball Pitch OpenAIRE Backus, Sherry I.; Kraszewski, Andrew; Kontaxis, Andreas; Gibbons, Mandi; Bido, Jennifer; Graziano, Jessica; Hafer, Jocelyn; Jones, Kristofer J.; Hillstrom, Howard; Fealy, Stephen 2013-01-01 Objectives: Pitch count has been studied extensively in the overhand throwing athlete. However, pitch count and fatigue have not been systematically evaluated in the female windmill (underhand) throwing athlete. Direct kinematic measurements of the glenohumeral and scapulo-thoracic joint have not to be correlated and determined. The purpose is to measure scapular kinematics for the high school female windmill softball pitcher and identify kinematic adaptions and changes in pitching performanc... 9. The launch region of the SVS 13 outflow and jet Energy Technology Data Exchange (ETDEWEB) Hodapp, Klaus W. [Institute for Astronomy, University of Hawaii, 640 North Aohoku Place, Hilo, HI 96720 (United States); Chini, Rolf, E-mail: hodapp@ifa.hawaii.edu, E-mail: rolf.chini@astro.ruhr-uni-bochum.de [Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum (Germany) 2014-10-20 We present the results of Keck telescope laser adaptive-optics integral field spectroscopy with OSIRIS of the innermost regions of the NGC 1333 SVS 13 outflow that forms the system of Herbig-Haro objects 7-11. We find a bright 0.''2 long microjet traced by the emission of shock-excited [Fe II]. Beyond the extent of this jet, we find a series of bubbles and fragments of bubbles that are traced in the lower excitation H{sub 2} 1-0 S(1) line. While the most recent outflow activity is directed almost precisely (P.A. ≈ 145°) to the southeast of SVS 13, there is clear indication that prior bubble ejections were pointed in different directions. Within these variations, a clear connection between the newly observed bubble ejection events and the well-known, poorly collimated HH 7-11 system of Herbig-Haro objects is established. The astrometry of the youngest of the expanding shock fronts at three epochs, covering a timespan of over 2 yr, gives kinematic ages for two of these bubbles. The kinematic age of the youngest bubble is slightly older than the historically observed last photometric outburst of SVS 13 in 1990, consistent with that event, launching the bubble and some deceleration of its expansion. A re-evaluation of historic infrared photometry and new data show that SVS 13 has not yet returned to its brightness before that outburst and thus reveal behavior similar to FUor outbursts, albeit with a smaller amplitude. We postulate that the creation of a series of bubbles and the changes in outflow direction are indicative of a precessing disk and accretion events triggered by a repetitive phenomenon possibly linked to the orbit of a close binary companion. However, our high-resolution images in the H and K bands do not directly detect any companion object. We have tried, but failed, to detect the kinematic rotation signature of the microjet in the [Fe II] emission line at 1.644 μm. 10. The Launch Region of the SVS 13 Outflow and Jet Science.gov (United States) Hodapp, Klaus W.; Chini, Rolf 2014-10-01 We present the results of Keck telescope laser adaptive-optics integral field spectroscopy with OSIRIS of the innermost regions of the NGC 1333 SVS 13 outflow that forms the system of Herbig-Haro objects 7-11. We find a bright 0.''2 long microjet traced by the emission of shock-excited [Fe II]. Beyond the extent of this jet, we find a series of bubbles and fragments of bubbles that are traced in the lower excitation H2 1-0 S(1) line. While the most recent outflow activity is directed almost precisely (P.A. ≈ 145°) to the southeast of SVS 13, there is clear indication that prior bubble ejections were pointed in different directions. Within these variations, a clear connection between the newly observed bubble ejection events and the well-known, poorly collimated HH 7-11 system of Herbig-Haro objects is established. The astrometry of the youngest of the expanding shock fronts at three epochs, covering a timespan of over 2 yr, gives kinematic ages for two of these bubbles. The kinematic age of the youngest bubble is slightly older than the historically observed last photometric outburst of SVS 13 in 1990, consistent with that event, launching the bubble and some deceleration of its expansion. A re-evaluation of historic infrared photometry and new data show that SVS 13 has not yet returned to its brightness before that outburst and thus reveal behavior similar to FUor outbursts, albeit with a smaller amplitude. We postulate that the creation of a series of bubbles and the changes in outflow direction are indicative of a precessing disk and accretion events triggered by a repetitive phenomenon possibly linked to the orbit of a close binary companion. However, our high-resolution images in the H and K bands do not directly detect any companion object. We have tried, but failed, to detect the kinematic rotation signature of the microjet in the [Fe II] emission line at 1.644 μm. 11. The launch region of the SVS 13 outflow and jet International Nuclear Information System (INIS) Hodapp, Klaus W.; Chini, Rolf 2014-01-01 We present the results of Keck telescope laser adaptive-optics integral field spectroscopy with OSIRIS of the innermost regions of the NGC 1333 SVS 13 outflow that forms the system of Herbig-Haro objects 7-11. We find a bright 0.''2 long microjet traced by the emission of shock-excited [Fe II]. Beyond the extent of this jet, we find a series of bubbles and fragments of bubbles that are traced in the lower excitation H 2 1-0 S(1) line. While the most recent outflow activity is directed almost precisely (P.A. ≈ 145°) to the southeast of SVS 13, there is clear indication that prior bubble ejections were pointed in different directions. Within these variations, a clear connection between the newly observed bubble ejection events and the well-known, poorly collimated HH 7-11 system of Herbig-Haro objects is established. The astrometry of the youngest of the expanding shock fronts at three epochs, covering a timespan of over 2 yr, gives kinematic ages for two of these bubbles. The kinematic age of the youngest bubble is slightly older than the historically observed last photometric outburst of SVS 13 in 1990, consistent with that event, launching the bubble and some deceleration of its expansion. A re-evaluation of historic infrared photometry and new data show that SVS 13 has not yet returned to its brightness before that outburst and thus reveal behavior similar to FUor outbursts, albeit with a smaller amplitude. We postulate that the creation of a series of bubbles and the changes in outflow direction are indicative of a precessing disk and accretion events triggered by a repetitive phenomenon possibly linked to the orbit of a close binary companion. However, our high-resolution images in the H and K bands do not directly detect any companion object. We have tried, but failed, to detect the kinematic rotation signature of the microjet in the [Fe II] emission line at 1.644 μm. 12. Heavy baryon spectroscopy with relativistic kinematics International Nuclear Information System (INIS) Valcarce, A.; Garcilazo, H.; Vijande, J. 2014-01-01 We present a comparative Faddeev study of heavy baryon spectroscopy with nonrelativistic and relativistic kinematics. We show results for different standard hyperfine interactions with both kinematics in an attempt to learn about the light quark dynamics. We highlight the properties of particular states accessible in nowadays laboratories that would help in discriminating between different dynamical models. The advance in the knowledge of light quark dynamics is a key tool for the understanding of the existence of exotic hadrons. 13. Deep-inelastic electroproduction of neutrons in the proton fragmentation region International Nuclear Information System (INIS) Kopeliovich, B.; Povh, B.; Potashnikova, I. 1996-01-01 Experiments at HERA looking for deep-inelastic electroproduction of neutrons in the proton fragmentation region are in process. They are aimed to measure the pion structure function at small Bjorken x. The important condition for such a study is to establish under what kinematical conditions the dominance of the pion-pole graph in the process is guaranteed. We analyse other sources of the leading neutron, in order to figure out the kinematical region where the one-pion exchange dominates. (orig.) 14. Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN Energy Technology Data Exchange (ETDEWEB) Ilić, Dragana [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Shapovalova, Alla I. [Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz (Russian Federation); Popović, Luka Č. [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Astronomical Observatory, Belgrade (Serbia); Chavushyan, Vahram [Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla (Mexico); Burenkov, Alexander N. [Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz (Russian Federation); Kollatschny, Wolfram [Institut fuer Astrophysik, Universitaet Goettingen, Göttingen (Germany); Kovačević, Andjelka [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Marčeta-Mandić, Sladjana [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Astronomical Observatory, Belgrade (Serbia); Rakić, Nemanja [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Faculty of Science, University of Banjaluka, Banjaluka, Republic of Srpska (Bosnia and Herzegovina); La Mura, Giovanni; Rafanelli, Piero, E-mail: dilic@math.rs [Department of Physics and Astronomy, University of Padova, Padova (Italy) 2017-09-14 We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN) coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1) AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR) of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties. 15. Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN Directory of Open Access Journals (Sweden) Dragana Ilić 2017-09-01 Full Text Available We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1 AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties. 16. Extended emission-line regions in active galaxies International Nuclear Information System (INIS) Hutchings, J.B.; Hickson, P. 1988-01-01 Long-slit spectra of four active galaxies in the redshift range 0.06-0.10 are presented. Two have interacting companions. Spectra of the galaxies show extended narrow emission lines in all cases. Continuum color changes, emision-line ratio changes, and velocity changes with 1 arcsec resolution can be detected. Relative velocities between AGN and companion galaxies are also given. These objects appear to lie in galaxies in which there is considerable star-formation activity, and very extended line emision. 20 references 17. Acute toxicity effects of perfluorooctane sulfonate on sperm vitality, kinematics and fertilization success in zebrafish Science.gov (United States) Xia, Jigang; Niu, Cuijuan 2017-07-01 Perfluorooctane sulfonate (PFOS) has emerged as one of the most concerning contaminants in recent years. This study aimed to investigate the acute toxicity effect of PFOS on sperm viability, kinematics and fertilization success in zebrafish ( Danio rerio). Sperm were activated in aqueous media containing a range of PFOS concentrations (0, 0.09, 0.9 and 9 mg/L). Viabilities and kinematics of the sperm exposed to different PFOS treatments were assessed via computer-assisted sperm analysis (CASA) at 20, 40, 60, and 80 s after activation. PFOS exposure decreased the percentage of motile sperm, the curvilinear velocity (VCL), and the mean angular displacement (MAD) of spermatozoa, but showed no influence on the straight-line velocity (VSL) or the angular path velocity (VAP). Furthermore, a significant decrease in fertilization success was observed in spermatozoa that were exposed to 0.9 mg/L PFOS or more. These findings indicate that PFOS pollution in natural aquatic environment may be a potential threaten to successful reproduction of fish. 18. Kinematic and neuromuscular relationships between lower extremity clinical movement assessments. Science.gov (United States) Mauntel, Timothy C; Cram, Tyler R; Frank, Barnett S; Begalle, Rebecca L; Norcross, Marc F; Blackburn, J Troy; Padua, Darin A 2018-06-01 Lower extremity injuries have immediate and long-term consequences. Lower extremity movement assessments can assist with identifying individuals at greater injury risk and guide injury prevention interventions. Movement assessments identify similar movement characteristics and evidence suggests large magnitude kinematic relationships exist between movement patterns observed across assessments; however, the magnitude of the relationships for electromyographic (EMG) measures across movement assessments remains largely unknown. This study examined relationships between lower extremity kinematic and EMG measures during jump landings and single leg squats. Lower extremity three-dimensional kinematic and EMG data were sampled from healthy adults (males = 20, females = 20) during the movement assessments. Pearson correlations examined the relationships of the kinematic and EMG measures and paired samples t-tests compared mean kinematic and EMG measures between the assessments. Overall, significant moderate correlations were observed for lower extremity kinematic (r avg = 0.41, r range = 0.10-0.61) and EMG (r avg = 0.47, r range = 0.32-0.80) measures across assessments. Kinematic and EMG measures were greater during the jump landings. Jump landings and single leg squats place different demands on the body and necessitate different kinematic and EMG patterns, such that these measures are not highly correlated between assessments. Clinicians should, therefore, use multiple assessments to identify aberrant movement and neuromuscular control patterns so that comprehensive interventions can be implemented. 19. IR finite one-loop box scalar integral with massless internal lines International Nuclear Information System (INIS) Duplancic, G.; Nizic, B. 2002-01-01 The IR finite one-loop box scalar integral with massless internal lines has been recalculated. The result is very compact, simple and valid for arbitrary values of the relevant kinematic variables. It is given in terms of only two dilogarithms and a few logarithms, all of very simple arguments. (orig.) 20. Inverse kinematics of a dual linear actuator pitch/roll heliostat Science.gov (United States) Freeman, Joshua; Shankar, Balakrishnan; Sundaram, Ganesh 2017-06-01 This work presents a simple, computationally efficient inverse kinematics solution for a pitch/roll heliostat using two linear actuators. The heliostat design and kinematics have been developed, modeled and tested using computer simulation software. A physical heliostat prototype was fabricated to validate the theoretical computations and data. Pitch/roll heliostats have numerous advantages including reduced cost potential and reduced space requirements, with a primary disadvantage being the significantly more complicated kinematics, which are solved here. Novel methods are applied to simplify the inverse kinematics problem which could be applied to other similar problems. 1. Interactive cervical motion kinematics: sensitivity, specificity and clinically significant values for identifying kinematic impairments in patients with chronic neck pain. Science.gov (United States) Sarig Bahat, Hilla; Chen, Xiaoqi; Reznik, David; Kodesh, Einat; Treleaven, Julia 2015-04-01 Chronic neck pain has been consistently shown to be associated with impaired kinematic control including reduced range, velocity and smoothness of cervical motion, that seem relevant to daily function as in quick neck motion in response to surrounding stimuli. The objectives of this study were: to compare interactive cervical kinematics in patients with neck pain and controls; to explore the new measures of cervical motion accuracy; and to find the sensitivity, specificity, and optimal cutoff values for defining impaired kinematics in those with neck pain. In this cross-section study, 33 patients with chronic neck pain and 22 asymptomatic controls were assessed for their cervical kinematic control using interactive virtual reality hardware and customized software utilizing a head mounted display with built-in head tracking. Outcome measures included peak and mean velocity, smoothness (represented by number of velocity peaks (NVP)), symmetry (represented by time to peak velocity percentage (TTPP)), and accuracy of cervical motion. Results demonstrated significant and strong effect-size differences in peak and mean velocities, NVP and TTPP in all directions excluding TTPP in left rotation, and good effect-size group differences in 5/8 accuracy measures. Regression results emphasized the high clinical value of neck motion velocity, with very high sensitivity and specificity (85%-100%), followed by motion smoothness, symmetry and accuracy. These finding suggest cervical kinematics should be evaluated clinically, and screened by the provided cut off values for identification of relevant impairments in those with neck pain. Such identification of presence or absence of kinematic impairments may direct treatment strategies and additional evaluation when needed. Copyright © 2014 Elsevier Ltd. All rights reserved. 2. Evaluation of Handwriting Movement Kinematics: From an Ecological to a Magnetic Resonance Environment Science.gov (United States) Bisio, Ambra; Pedullà, Ludovico; Bonzano, Laura; Ruggeri, Piero; Brichetto, Giampaolo; Bove, Marco 2016-01-01 Writing is a means of communication which requires complex motor, perceptual, and cognitive skills. If one of these abilities gets lost following traumatic events or due to neurological diseases, handwriting could deteriorate. Occupational therapy practitioners provide rehabilitation services for people with impaired handwriting. However, to determine the effectiveness of handwriting interventions no studies assessed whether the proposed treatments improved the kinematics of writing movement or had an effect at the level of the central nervous system. There is need to find new quantitative methodologies able to describe the behavioral and the neural outcomes of the rehabilitative interventions for handwriting. In the present study we proposed a combined approach that allowed evaluating the kinematic parameters of handwriting movements, acquired by means of a magnetic resonance-compatible tablet, and their neural correlates obtained simultaneously from a functional magnetic resonance imaging examination. Results showed that the system was reliable in term of reproducibility of the kinematic data during a test/re-test procedure. Further, despite the modifications with respect to an ecological writing movement condition, the kinematic parameters acquired inside the MR-environment were descriptive of individuals’ movement features. At last, the imaging protocol succeeded to show the activation of the cerebral regions associated with the production of writing movement in healthy people. From these findings, this methodology seems to be promising to evaluate the handwriting movement deficits and the potential alterations in the neural activity in those individuals who have handwriting difficulties. Finally, it would provide a mean to quantitatively assess the effect of a rehabilitative treatment. PMID:27746727 3. Evaluation of handwriting movement kinematics: from an ecological to a magnetic resonance environment Directory of Open Access Journals (Sweden) Ambra Bisio 2016-09-01 Full Text Available Writing is a means of communication which requires complex motor, perceptual and cognitive skills. If one of these abilities gets lost following traumatic events or due to neurological diseases, handwriting could deteriorate. Occupational therapy practitioners provide rehabilitation services for people with impaired handwriting. However, to determine the effectiveness of handwriting interventions no studies assessed whether the proposed treatments improved the kinematics of writing movement or had an effect at the level of the central nervous system. There is need to find new quantitative methodologies able to describe the behavioral and the neural outcomes of the rehabilitative interventions for handwriting. In the present study we proposed a combined approach that allowed evaluating the kinematic parameters of handwriting movements, acquired by means of a magnetic resonance-compatible tablet, and their neural correlates obtained simultaneously from a functional magnetic resonance imaging (fMRI examination. Results showed that the system was reliable in term of reproducibility of the kinematic data during a test/re-test procedure. Further, despite the modifications with respect to an ecological writing movement condition, the kinematic parameters acquired inside the MR-environment were descriptive of individuals’ movement features. At last, the imaging protocol succeeded to show the activation of the cerebral regions associated with the production of writing movement in healthy people. From these findings, this methodology seems to be promising to evaluate the handwriting movement deficits and the potential alterations in the neural activity in those individuals who have handwriting difficulties. Finally, it would provide a mean to quantitatively assess the effect of a rehabilitative treatment. 4. Kinematic Hardening: Characterization, Modeling and Impact on Springback Prediction International Nuclear Information System (INIS) Alves, J. L.; Bouvier, S.; Jomaa, M.; Billardon, R.; Oliveira, M. C.; Menezes, L. F. 2007-01-01 The constitutive modeling of the materials' mechanical behavior, usually carried out using a phenomenological constitutive model, i.e., a yield criterion associated to the isotropic and kinematic hardening laws, is of paramount importance in the FEM simulation of the sheet metal forming processes, as well as in the springback prediction. Among others, the kinematic behavior of the yield surface plays an essential role, since it is indispensable to describe the Bauschinger effect, i.e., the materials' answer to the multiple tension-compression cycles to which material points are submitted during the forming process. Several laws are usually used to model and describe the kinematic hardening, namely: a) the Prager's law, which describes a linear evolution of the kinematic hardening with the plastic strain rate tensor b) the Frederick-Armstrong non-linear kinematic hardening, basically a non-linear law with saturation; and c) a more advanced physically-based law, similar to the previous one but sensitive to the strain path changes. In the present paper a mixed kinematic hardening law (linear + non-linear behavior) is proposed and its implementation into a static fully-implicit FE code is described. The material parameters identification for sheet metals using different strategies, and the classical Bauschinger loading tests (i.e. in-plane forward and reverse monotonic loading), are addressed, and their impact on springback prediction evaluated. Some numerical results concerning the springback prediction of the Numisheet'05 Benchmark no. 3 are briefly presented to emphasize the importance of a correct modeling and identification of the kinematic hardening behavior 5. DIDACTIC AUTOMATED STATION OF COMPLEX KINEMATICS Directory of Open Access Journals (Sweden) Mariusz Sosnowski 2014-03-01 Full Text Available The paper presents the design, control system and software that controls the automated station of complex kinematics. Control interface and software has been developed and manufactured in the West Pomeranian University of Technology in Szczecin in the Department of Automated Manufacturing Systems Engineering and Quality. Conducting classes designed to teach programming and design of structures and systems for monitoring the robot kinematic components with non-standard structures was the reason for installation of the control system and software. 6. Kinematical coincidence method in transfer reactions Energy Technology Data Exchange (ETDEWEB) Acosta, L.; Amorini, F. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Auditore, L. [INFN Gruppo Collegato di Messina and Dipartimento di Fisica, Università di Messina (Italy); Berceanu, I. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cardella, G., E-mail: cardella@ct.infn.it [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Chatterjiee, M.B. [Saha Institute for Nuclear Physics, Kolkata (India); De Filippo, E. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Francalanza, L.; Gianì, R. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); Grassi, L. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Rudjer Boskovic Institute, Zagreb (Croatia); Grzeszczuk, A. [Institut of Physics, University of Silesia, Katowice (Poland); La Guidara, E. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Lanzalone, G. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Facoltà di Ingegneria e Architettura, Università Kore, Enna (Italy); Lombardo, I. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Scienze Fisiche, Università Federico II and INFN Sezione di Napoli (Italy); Loria, D.; Minniti, T. [INFN Gruppo Collegato di Messina and Dipartimento di Fisica, Università di Messina (Italy); Pagano, E.V. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); and others 2013-07-01 A new method to extract high resolution angular distributions from kinematical coincidence measurements in binary reactions is presented. Kinematics is used to extract the center of mass angular distribution from the measured energy spectrum of light particles. Results obtained in the case of {sup 10}Be+p→{sup 9}Be+d reaction measured with the CHIMERA detector are shown. An angular resolution of few degrees in the center of mass is obtained. The range of applicability of the method is discussed. 7. An adaptive inverse kinematics algorithm for robot manipulators Science.gov (United States) Colbaugh, R.; Glass, K.; Seraji, H. 1990-01-01 An adaptive algorithm for solving the inverse kinematics problem for robot manipulators is presented. The algorithm is derived using model reference adaptive control (MRAC) theory and is computationally efficient for online applications. The scheme requires no a priori knowledge of the kinematics of the robot if Cartesian end-effector sensing is available, and it requires knowledge of only the forward kinematics if joint position sensing is used. Computer simulation results are given for the redundant seven-DOF robotics research arm, demonstrating that the proposed algorithm yields accurate joint angle trajectories for a given end-effector position/orientation trajectory. 8. Kinematic top analyses at CDF Energy Technology Data Exchange (ETDEWEB) Grassmann, H.; CDF Collaboration 1995-03-01 We present an update of the top quark analysis using kinematic techniques in p{bar p} collisions at {radical}s = 1.8 TeV with the Collider Detector at Fermilab (CDF). We reported before on a study which used 19.3 pb{sup {minus}1} of data from the 1992--1993 collider run, but now we use a larger data sample of 67 pb{sup {minus}1}. First, we analyze the total transverse energy of the hard collision in W+{ge}3 jet events, showing the likely presence of a t{bar t} component in the event sample. Next, we compare in more detail the kinematic structure of W+ {ge}3 jet events with expectations for top pair production and with background processes, predominantly direct W+ jet production. We again find W+ {ge} 3 jet events which cannot be explained in terms of background, but show kinematic features as expected from top. These events also show evidence for beauty quarks, in agreement with expectations from top, but not compatible with expectations from backgrounds. The findings confirm the observation of top events made earlier in the data of the 1992--1993 collider run. 9. Kinematics of the Ethiopian Rift and Absolute motion of Africa and Somalia Plates Science.gov (United States) Muluneh, A. A.; Cuffaro, M.; Doglioni, C. 2013-12-01 The Ethiopian Rift (ER), in the northern part of East African Rift System (EARS), forms a boundary zone accommodating differential motion between Africa and Somalia Plates. Its orientation was influenced by the inherited Pan-African collisional system and related lithospheric fabric. We present the kinematics of ER derived from compilation of geodetic velocities, focal mechanism inversions, structural data analysis, and construction of geological profiles. GPS velocity field shows a systematic eastward magnitude increase in NE direction in the central ER. In the same region, incremental extensional strain axes recorded by earthquake focal mechanism and fault slip inversion show ≈N1000E orientation. This deviation between GPS velocity trajectories and orientation of incremental extensional strain is developed due to left lateral transtensional deformation. This interpretation is consistent with the en-échelon pattern of tensional and transtensional faults, the distribution of the volcanic centers, and the asymmetry of the rift itself. Small amount of vertical axis blocks rotation, sinistral strike slip faults and dyke intrusions in the rift accommodate the transtensional deformation. We analyzed the kinematics of ER relative to Deep and Shallow Hot Spot Reference Frames (HSRF). Comparison between the two reference frames shows different kinematics in ER and also Africa and Somalia plate motion both in magnitude and direction. Plate spreading direction in shallow HSRF (i.e. the source of the plumes locates in the asthenosphere) and the trend of ER deviate by about 27°. Shearing and extension across the plate boundary zone contribute both to the style of deformation and overall kinematics in the rift. We conclude that the observed long wavelength kinematics and tectonics are consequences of faster SW ward motion of Africa than Somalia in the shallow HSRF. This reference frame seems more consistent with the geophysical and geological constraints in the Rift. The 10. Hexagon OPE resummation and multi-Regge kinematics Energy Technology Data Exchange (ETDEWEB) Drummond, J.M. [School of Physics & Astronomy, University of Southampton,Highfield, Southampton, SO17 1BJ (United Kingdom); Theory Division, Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); LAPTh, CNRS, Université de Savoie,9 Chemin de Bellevue, F-74941 Annecy-le-Vieux Cedex (France); Papathanasiou, G. [LAPTh, CNRS, Université de Savoie,9 Chemin de Bellevue, F-74941 Annecy-le-Vieux Cedex (France) 2016-02-29 We analyse the OPE contribution of gluon bound states in the double scaling limit of the hexagonal Wilson loop in planar N=4 super Yang-Mills theory. We provide a systematic procedure for perturbatively resumming the contributions from single-particle bound states of gluons and expressing the result order by order in terms of two-variable polylogarithms. We also analyse certain contributions from two-particle gluon bound states and find that, after analytic continuation to the 2→4 Mandelstam region and passing to multi-Regge kinematics (MRK), only the single-particle gluon bound states contribute. From this double-scaled version of MRK we are able to reconstruct the full hexagon remainder function in MRK up to five loops by invoking single-valuedness of the results. 11. Latest Advances in Robot Kinematics CERN Document Server Husty, Manfred 2012-01-01 This book is of interest to researchers inquiring about modern topics and methods in the kinematics, control and design of robotic manipulators. It considers the full range of robotic systems, including serial, parallel and cable driven manipulators, both planar and spatial. The systems range from being less than fully mobile to kinematically redundant to overconstrained. In addition to recognized areas, this book also presents recent advances in emerging areas such as the design and control of humanoids and humanoid subsystems, and the analysis, modeling and simulation of human body motions, as well as the mobility analysis of protein molecules and the development of machines which incorporate man. 12. Kinematic sensitivity of robot manipulators Science.gov (United States) Vuskovic, Marko I. 1989-01-01 Kinematic sensitivity vectors and matrices for open-loop, n degrees-of-freedom manipulators are derived. First-order sensitivity vectors are defined as partial derivatives of the manipulator's position and orientation with respect to its geometrical parameters. The four-parameter kinematic model is considered, as well as the five-parameter model in case of nominally parallel joint axes. Sensitivity vectors are expressed in terms of coordinate axes of manipulator frames. Second-order sensitivity vectors, the partial derivatives of first-order sensitivity vectors, are also considered. It is shown that second-order sensitivity vectors can be expressed as vector products of the first-order sensitivity vectors. 13. Color-Kinematics Duality for QCD Amplitudes CERN Document Server Johansson, Henrik 2016-01-01 We show that color-kinematics duality is present in tree-level amplitudes of quantum chromodynamics with massive flavored quarks. Starting with the color structure of QCD, we work out a new color decomposition for n-point tree amplitudes in a reduced basis of primitive amplitudes. These primitives, with k quark-antiquark pairs and (n-2k) gluons, are taken in the (n-2)!/k! Melia basis, and are independent under the color-algebra Kleiss-Kuijf relations. This generalizes the color decomposition of Del Duca, Dixon, and Maltoni to an arbitrary number of quarks. The color coefficients in the new decomposition are given by compact expressions valid for arbitrary gauge group and representation. Considering the kinematic structure, we show through explicit calculations that color-kinematics duality holds for amplitudes with general configurations of gluons and massive quarks. The new (massive) amplitude relations that follow from the duality can be mapped to a well-defined subset of the familiar BCJ relations for gluo... 14. Coordinate transformations, orthographic projections, and robot kinematics International Nuclear Information System (INIS) Crochetiere, W.J. 1984-01-01 Humans do not consciously think of moving each of their joints while they move their hands from one place to another. Likewise, robot arms can be commanded to move about in cartesian space without the need to address the individual joints. To do this, the direct and inverse kinematic equations of any robot arm must be derived. The direct kinematic equations uniquely transform the joint positions into the position (and orientation) of the hand, whereas the inverse kinematic equations transform the position (and orientation) of the hand into joint positions. The derivation of the inverse kinematic equations for any particular robot is a difficult problem which may have more than one solution. In this paper, these equations are derived for a six degree of freedom robot arm. A combination of matrix operations to perform coordinate rotations, and trigonometry within the appropriate orthographic projects to perform coordinate translations is employed. This complementary approach yields a solution which is more easily obtained, and also more easily visualized. The resulting solution was programmed into a real-time computer as a part of a higher level software system to control the motion of the arm 15. The kinematic algebras from the scattering equations International Nuclear Information System (INIS) Monteiro, Ricardo; O’Connell, Donal 2014-01-01 We study kinematic algebras associated to the recently proposed scattering equations, which arise in the description of the scattering of massless particles. In particular, we describe the role that these algebras play in the BCJ duality between colour and kinematics in gauge theory, and its relation to gravity. We find that the scattering equations are a consistency condition for a self-dual-type vertex which is associated to each solution of those equations. We also identify an extension of the anti-self-dual vertex, such that the two vertices are not conjugate in general. Both vertices correspond to the structure constants of Lie algebras. We give a prescription for the use of the generators of these Lie algebras in trivalent graphs that leads to a natural set of BCJ numerators. In particular, we write BCJ numerators for each contribution to the amplitude associated to a solution of the scattering equations. This leads to a decomposition of the determinant of a certain kinematic matrix, which appears naturally in the amplitudes, in terms of trivalent graphs. We also present the kinematic analogues of colour traces, according to these algebras, and the associated decomposition of that determinant 16. Absorption-line strengths of 18 late-type spiral galaxies observed with SAURON NARCIS (Netherlands) Ganda, Katia; Peletier, Reynier F.; McDermid, Richard M.; Falcon-Barroso, Jesus; de Zeeuw, P. T.; Bacon, Roland; Cappellari, Michele; Davies, Roger L.; Emsellem, Eric; Krajnovic, Davor; Kuntschner, Harald; Sarzi, Marc; van de Ven, Glenn 2007-01-01 We present absorption line strength maps for a sample of 18 Sb-Sd galaxies observed using the integral-field spectrograph SAURON operating at the William Herschel Telescope on La Palma, as part of a project devoted to the investigation of the kinematics and stellar populations of late-type spirals, 17. Estimation of kinematic parameters in CALIFA galaxies: no-assumption on internal dynamics Science.gov (United States) García-Lorenzo, B.; Barrera-Ballesteros, J.; CALIFA Team 2016-06-01 We propose a simple approach to homogeneously estimate kinematic parameters of a broad variety of galaxies (elliptical, spirals, irregulars or interacting systems). This methodology avoids the use of any kinematical model or any assumption on internal dynamics. This simple but novel approach allows us to determine: the frequency of kinematic distortions, systemic velocity, kinematic center, and kinematic position angles which are directly measured from the two dimensional-distributions of radial velocities. We test our analysis tools using the CALIFA Survey 18. Kinematic seismic response of piles in layered soil profile International Nuclear Information System (INIS) Ahmad, I.; Khan, A.N. 2006-01-01 This paper is aimed at highlighting the importance of Kinematic Seismic Response of Piles, a phenomenon often ignored in dynamic analysis. A case study is presented where the end bearing pile is embedded in two layer soil system of highly contrasting stiffnesses; a typical case where kinematic loading plays important role. The pile soil system is modeled as continuous system and as discrete parameter system; both are based on BDWF (Beam on Dynamic Winkler Foundation) formulation. For discrete parameter system, a finite element software SAP2000 is used and the modeling technique of kinematic interaction in finite element software is discussed. For pile soil system modeled as continuous system, a general MATLAB code is developed capable of performing elastic site response analysis in two layer soil system, solving differential equation governing kinematic interaction, and giving as output the maximum ground displacement, maximum pile displacement, rotation, moment and shear distribution along pile length. The paper concludes that kinematic seismic actions must be evaluated particularly at the interface of soil layers of significantly differing soil stiffnesses. (author) 19. Inverse Kinematics of a Serial Robot Directory of Open Access Journals (Sweden) Amici Cinzia 2016-01-01 Full Text Available This work describes a technique to treat the inverse kinematics of a serial manipulator. The inverse kinematics is obtained through the numerical inversion of the Jacobian matrix, that represents the equation of motion of the manipulator. The inversion is affected by numerical errors and, in different conditions, due to the numerical nature of the solver, it does not converge to a reasonable solution. Thus a soft computing approach is adopted to mix different traditional methods to obtain an increment of algorithmic convergence. 20. The effect of ankle bracing on knee kinetics and kinematics during volleyball-specific tasks. Science.gov (United States) West, T; Ng, L; Campbell, A 2014-12-01 The purpose of this study was to examine the effects of ankle bracing on knee kinetics and kinematics during volleyball tasks. Fifteen healthy, elite, female volleyball players performed a series of straight-line and lateral volleyball tasks with no brace and when wearing an ankle brace. A 14-camera Vicon motion analysis system and AMTI force plate were used to capture the kinetic and kinematic data. Knee range of motion, peak knee anterior-posterior and medial-lateral shear forces, and peak ground reaction forces that occurred between initial contact with the force plate and toe off were compared using paired sample t-tests between the braced and non-braced conditions (P volleyball tasks. However, ankle bracing was demonstrated to reduce knee lateral shear forces during all of the lateral movement volleyball tasks. Wearing the Active Ankle T2 brace will not impact knee joint range of motion and may in fact reduce shear loading to the knee joint in volleyball players. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. 1. THE STELLAR AND GAS KINEMATICS OF THE LITTLE THINGS DWARF IRREGULAR GALAXY NGC 1569 Energy Technology Data Exchange (ETDEWEB) Johnson, Megan [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Hunter, Deidre A.; Zhang, Hong-Xin; Herrmann, Kimberly [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Oh, Se-Heon [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Elmegreen, Bruce [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Hts., NY 10598 (United States); Brinks, Elias [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom); Tollerud, Erik, E-mail: mjohnson@nrao.edu, E-mail: dah@lowell.edu, E-mail: hxzhang@lowell.edu, E-mail: herrmann@lowell.edu, E-mail: se-heon.oh@uwa.edu.au, E-mail: bge@us.ibm.com, E-mail: E.Brinks@herts.ac.uk, E-mail: etolleru@uci.edu [Center For Cosmology, Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States) 2012-11-01 In order to understand the formation and evolution of Magellanic-type dwarf irregular (dIm) galaxies, one needs to understand their three-dimensional structure. We present measurements of the stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy. The stellar vertical velocity dispersion, {sigma}{sub z}, coupled with the maximum rotational velocity derived from H I observations, V{sub max}, gives a measure of how kinematically hot the galaxy is, and, therefore, indicates its structure. We conclude that the stars in NGC 1569 are in a thick disk with a V{sub max}/{sigma}{sub z} = 2.4 {+-} 0.7. In addition to the structure, we analyze the ionized gas kinematics from O III observations along the morphological major axis. These data show evidence for outflow from the inner starburst region and a potential expanding shell near supermassive star cluster (SSC) A. When compared to the stellar kinematics, the velocity dispersion of the stars increases in the region of SSC A supporting the hypothesis of an expanding shell. The stellar kinematics closely follow the motion of the gas. Analysis of high-resolution H I data clearly reveals the presence of an H I cloud that appears to be impacting the eastern edge of NGC 1569. Also, an ultra-dense H I cloud can be seen extending to the west of the impacting H I cloud. This dense cloud is likely the remains of a dense H I bridge that extended through what is now the central starburst area. The impacting H I cloud was the catalyst for the starburst, thus turning the dense gas into stars over a short timescale, {approx}1 Gyr. We performed a careful study of the spectral energy distribution using infrared, optical, and ultraviolet photometry, producing a state-of-the-art mass model for the stellar disk. This mass modeling shows that stars dominate the gravitational potential in the inner 1 kpc. The dynamical mass of NGC 1569, derived from V{sub max}, shows that the disk may be dark matter deficient in the inner 2. Teaching about Kinematics Science.gov (United States) Nelson, Jane Bray; Nelson, Jim 2009-01-01 Written by Jim and Jane Nelson, Teaching About Kinematics is the latest AAPT/PTRA resource book. Based on physics education research, the book provides teachers with the resources needed to introduce students to some of the fundamental building blocks of physics. It is a carefully thought-out, step-by-step laboratory-based introduction to the… 3. Kinematic cross-correlation induces sensory integration across separate objects. Science.gov (United States) Debats, Nienke B; Ernst, Marc O; Heuer, Herbert 2017-12-01 In a basic cursor-control task, the perceived positions of the hand and the cursor are biased towards each other. We recently found that this phenomenon conforms to the reliability-based weighting mechanism of optimal multisensory integration. This indicates that optimal integration is not restricted to sensory signals originating from a single source, as is the prevailing view, but that it also applies to separate objects that are connected by a kinematic relation (i.e. hand and cursor). In the current study, we examined which aspects of the kinematic relation are crucial for eliciting the sensory integration: (i) the cross-correlation between kinematic variables of the hand and cursor trajectories, and/or (ii) an internal model of the hand-cursor kinematic transformation. Participants made out-and-back movements from the centre of a semicircular workspace to its boundary, after which they judged the position where either their hand or the cursor hit the boundary. We analysed the position biases and found that the integration was strong in a condition with high kinematic correlations (a straight hand trajectory was mapped to a straight cursor trajectory), that it was significantly reduced for reduced kinematic correlations (a straight hand trajectory was transformed into a curved cursor trajectory) and that it was not affected by the inability to acquire an internal model of the kinematic transformation (i.e. by the trial-to-trial variability of the cursor curvature). These findings support the idea that correlations play a crucial role in multisensory integration irrespective of the number of sensory sources involved. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd. 4. Kinematic variables of table vault on artistic gymnastics Directory of Open Access Journals (Sweden) Sarah Maria Boldrini FERNANDES 2016-03-01 Full Text Available Abstract The table vault is an event of male and female Artistics Gymnastics. Although it can be performed in a variety of rotations and body positions in different phases, it can be separated in three groups: handspring, Yurchenko and Tsukahara. It is believed that kinematic variables of vault may vary according to group of vault or gymnast body position, but few studies compares the real differences among the three groups of vaults, comparing and describing the variables in different phases. Vault kinematic variables could be diversifying according to the approach or position of the vaulting, but little has been studied about the biomechanical differences, comparing and describing behaviours at different stages. The aim of this study was to organize critical, objective and to systematize the most relevant kinematic variables to performance on vaulting. A Meta analysis over the basis Pubmed, Sport Discus and Web of Science were performed about this issue. From the selected references, we described and analyzed the kinematics of the table vault. Vault can be characterized in seven phases of analysis. Most of the studies are descriptive, and some do not descript all phases. Differences among vault variables according to group vaults, technical level and gender were analysed only in recent studies. There still gaps of knowledge about kinematic variables of table vault, in order to provide comprehensive information about all possibilities of vaults in this gymnastic event. It is concluded that kinematic variables of table vault depends upon vault group and may be considered to the improvement of technical performance. More researches are needed to approach the coaching interface with biomechanics applicable knowledge. 5. Dynamical evolution of star-forming regions - II. Basic kinematics Science.gov (United States) Parker, Richard J.; Wright, Nicholas J. 2016-04-01 We follow the dynamical evolution of young star-forming regions with a wide range of initial conditions and examine how the radial velocity dispersion, σ, evolves over time. We compare this velocity dispersion to the theoretically expected value for the velocity dispersion if a region were in virial equilibrium, σvir and thus assess the virial state (σ/σvir) of these systems. We find that in regions that are initially subvirial, or in global virial equilibrium but subvirial on local scales, the system relaxes to virial equilibrium within several million years, or roughly 25-50 crossing times, according to the measured virial ratio. However, the measured velocity dispersion, σ, appears to be a bad diagnostic of the current virial state of these systems as it suggests that they become supervirial when compared to the velocity dispersion estimated from the virial mass, σvir. We suggest that this discrepancy is caused by the fact that the regions are never fully relaxed, and that the early non-equilibrium evolution is imprinted in the one-dimensional velocity dispersion at these early epochs. If measured early enough (interquartile range (IQR) dispersion, with measures of spatial structure, places stronger constraints on the dynamical history of a region than using the velocity dispersion in isolation. 6. Abnormal tibiofemoral contact stress and its association with altered kinematics following center-center ACL reconstruction: an in vitro study Science.gov (United States) Imhauser, Carl; Mauro, Craig; Choi, Daniel; Rosenberg, Eric; Mathew, Stephen; Nguyen, Joseph; Ma, Yan; Wickiewicz, Thomas 2014-01-01 Background Abnormal tibiofemoral contact stress and aberrant kinematics may influence the progression of osteoarthritis in the ACL-deficient and the ACL-reconstructed knee. However, relationships between contact stress and kinematics following ACL reconstruction are poorly understood. Therefore, we posed the following research questions: (1) How do ACL deficiency and reconstruction affect kinematics of and contact stress in the tibiofemoral joint? (2) What kinematic differences are associated with abnormal contact stress following ACL reconstruction? Hypothesis/Purpose Center-center ACL reconstruction will not restore knee kinematics and contact stress. Correlations will exist between abnormal contact stress and aberrant kinematics following ACL reconstruction will exist. Study Design Controlled laboratory study Methods Clinical tests of anterior and rotational stability were simulated on eleven cadaveric knees using an industrial robot. Tests were conducted with the ACL intact, sectioned, and after single bundle ACL reconstruction using a quadrupled hamstring autograft with tunnels drilled through the center of the native footprints. Kinematics were recorded during the tests. Contact stress was continuously recorded from a stress transducer fixed to the tibial plateau and mean contact stress was calculated regionally. Results ACL deficiency resulted in increased mean contact stress in the posterior sectors of the medial and lateral compartments under anterior and rotational loads, respectively. Reconstruction reduced stress in these locations; however contact stress abnormalities remained. On average, kinematics were overconstrained following ACL reconstruction (≤1.8mm and ≤2.6° in all directions). However, combinations of overconstrained and underconstrained motions in ab/adduction and medial-lateral translation in response to combined moments, and axial rotation, anterior-posterior and medial-lateral translation in response to an anterior load were 7. Uncertainty estimation and multi sensor fusion for kinematic laser tracker measurements Science.gov (United States) Ulrich, Thomas 2013-08-01 Laser trackers are widely used to measure kinematic tasks such as tracking robot movements. Common methods to evaluate the uncertainty in the kinematic measurement include approximations specified by the manufacturers, various analytical adjustment methods and the Kalman filter. In this paper a new, real-time technique is proposed, which estimates the 4D-path (3D-position + time) uncertainty of an arbitrary path in space. Here a hybrid system estimator is applied in conjunction with the kinematic measurement model. This method can be applied to processes, which include various types of kinematic behaviour, constant velocity, variable acceleration or variable turn rates. The new approach is compared with the Kalman filter and a manufacturer's approximations. The comparison was made using data obtained by tracking an industrial robot's tool centre point with a Leica laser tracker AT901 and a Leica laser tracker LTD500. It shows that the new approach is more appropriate to analysing kinematic processes than the Kalman filter, as it reduces overshoots and decreases the estimated variance. In comparison with the manufacturer's approximations, the new approach takes account of kinematic behaviour with an improved description of the real measurement process and a reduction in estimated variance. This approach is therefore well suited to the analysis of kinematic processes with unknown changes in kinematic behaviour as well as the fusion among laser trackers. 8. Dose exposure work planning using DMU kinematics tools International Nuclear Information System (INIS) Rosli Darmawan 2010-01-01 The study on the possibility of using DMU Kinematics module in CAE tools for dose exposure work planning was carried out. A case scenario was created using 3D CAD software and transferred to DMU Kinematics module in CAE software. A work plan was created using DMU Kinematics tools and animated to simulate a real time scenario. Data on the phantom position against the radioactive source was collected by activating positioning sensors in the module. The data was used to estimate dose rate exposure for the phantom. The results can be used to plan the safest and optimum procedures in carrying out the radiation related task. (author) 9. Kinematic evolution of the Mbakop Pan-African granitoids (western Cameroon domain): An integrated AMS and EBSD approach Science.gov (United States) Bella Nké, B. E.; Njanko, T.; Mamtani, M. A.; Njonfang, E.; Rochette, P. 2018-06-01 This study integrates anisotropy of magnetic susceptibility, microstructural and crystallographic preferred orientation (CPO) data from the Mbakop granitic pluton (MGP; Pan-African age) in order to decipher its kinematic evolution. The MGP lies close to NE-SW branch of Central Cameroon Shear Zone (CCSZ) and is emplaced in gneissic basement. High mean magnetic susceptibility and presence of multi-domain magnetite are recorded. Quartz CPO measured using Electron Backscatter diffraction reveals dominance of rhomb , prism and prism slip in different samples, which is consistent with microstructures developed under upper greenschist/amphibolite facies conditions. Quartz CPO along with other kinematic indicators (feldspar porphyroclasts/mineral fish) indicate non-coaxial deformation was important during tectonic evolution of the MGP. Contrasting sense of shear is recorded implying multi-stage mylonitization in the Western Cameroon Domain. Top-towards-south sense of shear is related to regional D2 deformation (613-585 Ma), while top-towards-north is related to D3 (585-540 Ma). The magnetic fabric in MGP records D3. The obliquity between mean orientation of magnetic foliation (N12°E) and the NE-SW CCSZ branch (N48°E) gives kinematic vorticity number of 0.95. This indicates dominantly simple shear with a minor pure shear component. It is concluded that regional transpression was important during MGP emplacement. 10. Analisys and Choice of the Exoskeleton’s Actuator Kinematic Structure Directory of Open Access Journals (Sweden) A. A. Vereikin 2014-01-01 Full Text Available The urgency of designing of robotic exoskeletons as one of the most prospective means of modern robotics is proved. A literature review concerning the design issues of anthropomorphic walking robots and exoskeletons is performed. Some problems, accompanying the designing process of exoskeleton actuator, are highlighted. Among them synthesis of its tree-like kinematic structure takes leading place. Its complication is explained by the specific human-machine interaction.The problem of exoskeleton actuator kinematic scheme synthesis is formulated and possible approaches to its solution are shown. The paper presents the synthesis results obtained using the software complex CATIA-based means of ergonomic design. It investigates the degrees of freedom of human-operator’s foot, shin, and thigh. And it identifies a number of shortcomings of this software complex associated with the ambiguity to solve the inverse kinematics problem, leading to a significant complication of kinematics synthesis.A model of human lower limb on which further studies of the exoskeleton actuator kinematic scheme, ensuring fulfillment of the human-operator standard movements (squats, kick their feet, bending body, walking, running stairs, etc., are based, is developed in SolidWorks software complex. The reasonability of the exoskeleton kinematic scheme synthesis in software package SolidWorks using anthropometric data from the software complex CATIA, is justified.The proposed method allows to analyze different kinematic schemes of actuator for the stage of conceptual design and to choose the best of them in accordance with established criterions. Thus, the developer receives the final version of the kinematic scheme before the detailed design of the actuator starts, thus significantly reducing its labor costs. 11. Observation of top quark production using kinematic techniques Energy Technology Data Exchange (ETDEWEB) Kim, Shinhong [Tsukuba Univ., Ibaraki (Japan); CDF Collaboration 1995-05-17 We present analysis results of the top quark production using kinematic techniques in p{bar p} collisions at {radical}s = 1.8 TeV with the Collider Detector at Fermilab (CDF). We analyzed a data sample corresponding to an integrated luminosity of 67 pb{sup {minus}1}. First, we compare the kinematic properties, the second and third leading jet E{sub T} of W+ > 3 jet events with expectations for t{bar t} production and its back-ground processes, predominantly direct W + jet production. The probability that backgrounds fake the excess in the signal region was found to be less than 0.26%. Next, we use a scaler sum of the transverse energies of the lepton, neutrino and jets in W+{ge}4 jet events. This analysis shows t{bar t} events exist significantly in the event sample, and enables us to estimate the top quark mass to be M{sub top} = 180 {plus_minus} 12 {sub {minus}15}{sup +19} GeV/c{sup 2}. Finally, we analyse the dijet invariant mass in the W+{ge}4 jet events. It shows a significant mass peak consistent with a mass peak of W decaying into dijet. From these results and counting experiment, we have confirmed previous evidence reported in 1994 April and observed top quark production. 12. Contact kinematics of biomimetic scales Energy Technology Data Exchange (ETDEWEB) Ghosh, Ranajay; Ebrahimi, Hamid; Vaziri, Ashkan, E-mail: vaziri@coe.neu.edu [Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115 (United States) 2014-12-08 Dermal scales, prevalent across biological groups, considerably boost survival by providing multifunctional advantages. Here, we investigate the nonlinear mechanical effects of biomimetic scale like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models, and detailed finite element (FE) analysis. Our results reveal the existence of three distinct kinematic phases of operation spanning linear, nonlinear, and rigid behavior driven by kinematic interactions of scales. The response of the modified elastic beam strongly depends on the size and spatial overlap of rigid scales. The nonlinearity is perceptible even in relatively small strain regime and without invoking material level complexities of either the scales or the substrate. 13. Simulation and experimental research on line throwing rocket with flight Directory of Open Access Journals (Sweden) Wen-bin Gu 2014-06-01 Full Text Available The finite segment method is used to model the line throwing rocket system. A dynamic model of line throwing rocket with flight motion based on Kane's method is presented by the kinematics description of the system and the consideration of the forces acting on the system. The experiment designed according to the parameters of the dynamic model is made. The simulation and experiment results, such as range, velocity and flight time, are compared and analyzed. The simulation results are basically agreed with the test data, which shows that the flight motion of the line throwing rocket can be predicted by the dynamic model. A theoretical model and guide for the further research on the disturbance of rope and the guidance, flight control of line throwing rocket are provided by the dynamic modeling. 14. RNA expression in a cartilaginous fish cell line reveals ancient 3′ noncoding regions highly conserved in vertebrates Science.gov (United States) Forest, David; Nishikawa, Ryuhei; Kobayashi, Hiroshi; Parton, Angela; Bayne, Christopher J.; Barnes, David W. 2007-01-01 We have established a cartilaginous fish cell line [Squalus acanthias embryo cell line (SAE)], a mesenchymal stem cell line derived from the embryo of an elasmobranch, the spiny dogfish shark S. acanthias. Elasmobranchs (sharks and rays) first appeared >400 million years ago, and existing species provide useful models for comparative vertebrate cell biology, physiology, and genomics. Comparative vertebrate genomics among evolutionarily distant organisms can provide sequence conservation information that facilitates identification of critical coding and noncoding regions. Although these genomic analyses are informative, experimental verification of functions of genomic sequences depends heavily on cell culture approaches. Using ESTs defining mRNAs derived from the SAE cell line, we identified lengthy and highly conserved gene-specific nucleotide sequences in the noncoding 3′ UTRs of eight genes involved in the regulation of cell growth and proliferation. Conserved noncoding 3′ mRNA regions detected by using the shark nucleotide sequences as a starting point were found in a range of other vertebrate orders, including bony fish, birds, amphibians, and mammals. Nucleotide identity of shark and human in these regions was remarkably well conserved. Our results indicate that highly conserved gene sequences dating from the appearance of jawed vertebrates and representing potential cis-regulatory elements can be identified through the use of cartilaginous fish as a baseline. Because the expression of genes in the SAE cell line was prerequisite for their identification, this cartilaginous fish culture system also provides a physiologically valid tool to test functional hypotheses on the role of these ancient conserved sequences in comparative cell biology. PMID:17227856 15. Relationship between sagittal plane kinematics, foot morphology and vertical forces applied to three regions of the foot OpenAIRE Hannah, I.; Sawacha, Z.; Guiotto, A.; Mazza, C. 2016-01-01 Kinetic analysis of human motion with a multi-segment musculoskeletal foot model requires the distribution of loading applied to the modeled foot segments to be determined. This work thus examines the existence of any correlation between intersegmental foot kinematics, foot morphology, and the distribution of vertical loading in a multi-segment foot model. Gait analysis trials were performed by 20 healthy subjects at a self-selected speed with intersegmental foot joint angles and the distribu... 16. Abnormal tibiofemoral contact stress and its association with altered kinematics after center-center anterior cruciate ligament reconstruction: an in vitro study. Science.gov (United States) Imhauser, Carl; Mauro, Craig; Choi, Daniel; Rosenberg, Eric; Mathew, Stephen; Nguyen, Joseph; Ma, Yan; Wickiewicz, Thomas 2013-04-01 Abnormal tibiofemoral contact stress and aberrant kinematics may influence the progression of osteoarthritis in the anterior cruciate ligament (ACL)-deficient and the ACL-reconstructed knee. However, relationships between contact stress and kinematics after ACL reconstruction are poorly understood. Therefore, we posed the following research questions: (1) How do ACL deficiency and reconstruction affect the kinematics of and contact stress in the tibiofemoral joint? (2) What kinematic differences are associated with abnormal contact stress after ACL reconstruction? Center-center ACL reconstruction will not restore knee kinematics and contact stress. Correlations will exist between abnormal contact stress and aberrant kinematics after ACL reconstruction. Controlled laboratory study. Clinical tests of anterior and rotational stability were simulated on 11 cadaveric knees using an industrial robot. Tests were conducted with the ACL intact, sectioned, and after single-bundle ACL reconstruction using a quadrupled hamstring autograft with tunnels drilled through the center of the native footprints. Kinematics were recorded during the tests. Contact stress was continuously recorded from a stress transducer fixed to the tibial plateau, and mean contact stress was calculated regionally. ACL deficiency resulted in increased mean contact stress in the posterior sectors of the medial and lateral compartments under anterior and rotational loads, respectively. Reconstruction reduced stress in these locations; however, contact stress abnormalities remained. On average, kinematics were overconstrained after ACL reconstruction (≤1.8 mm and ≤2.6° in all directions). However, combinations of overconstrained and underconstrained motions in abduction/adduction and medial-lateral translation in response to combined moments, and anterior-posterior translation, medial-lateral translation, and axial rotation in response to an anterior load were associated with abnormal mean contact 17. The Maiden Voyage of a Kinematics Robot Science.gov (United States) Greenwolfe, Matthew L. 2015-04-01 In a Montessori preschool classroom, students work independently on tasks that absorb their attention in part because the apparatus are carefully designed to make mistakes directly observable and limit exploration to one aspect or dimension. Control of error inheres in the apparatus itself, so that teacher intervention can be minimal.1 Inspired by this example, I created a robotic kinematics apparatus that also shapes the inquiry experience. Students program the robot by drawing kinematic graphs on a computer and then observe its motion. Exploration is at once limited to constant velocity and constant acceleration motion, yet open to complex multi-segment examples difficult to achieve in the lab in other ways. The robot precisely and reliably produces the motion described by the students' graphs, so that the apparatus itself provides immediate visual feedback about whether their understanding is correct as they are free to explore within the hard-coded limits. In particular, the kinematic robot enables hands-on study of multi-segment constant velocity situations, which lays a far stronger foundation for the study of accelerated motion. When correction is anonymous—just between one group of lab partners and their robot—students using the kinematic robot tend to flow right back to work because they view the correction as an integral part of the inquiry learning process. By contrast, when correction occurs by the teacher and/or in public (e.g., returning a graded assignment or pointing out student misconceptions during class), students all too often treat the event as the endpoint to inquiry. Furthermore, quantitative evidence shows a large gain from pre-test to post-test scores using the Test of Understanding Graphs in Kinematics (TUG-K). 18. Action experience changes attention to kinematic cues Directory of Open Access Journals (Sweden) Courtney eFilippi 2016-02-01 Full Text Available The current study used remote corneal reflection eye-tracking to examine the relationship between motor experience and action anticipation in 13-month-old infants. To measure online anticipation of actions infants watched videos where the actor’s hand provided kinematic information (in its orientation about the type of object that the actor was going to reach for. The actor’s hand orientation either matched the orientation of a rod (congruent cue or did not match the orientation of the rod (incongruent cue. To examine relations between motor experience and action anticipation, we used a 2 (reach first vs. observe first x 2 (congruent kinematic cue vs. incongruent kinematic cue between-subjects design. We show that 13-month-old infants in the observe first condition spontaneously generate rapid online visual predictions to congruent hand orientation cues and do not visually anticipate when presented incongruent cues. We further demonstrate that the speed that these infants generate predictions to congruent motor cues is correlated with their own ability to pre-shape their hands. Finally, we demonstrate that following reaching experience, infants generate rapid predictions to both congruent and incongruent hand shape cues—suggesting that short-term experience changes attention to kinematics. 19. Effect of suspension kinematic on 14 DOF vehicle model Science.gov (United States) Wongpattananukul, T.; Chantharasenawong, C. 2017-12-01 Computer simulations play a major role in shaping modern science and engineering. They reduce time and resource consumption in new studies and designs. Vehicle simulations have been studied extensively to achieve a vehicle model used in minimum lap time solution. Simulation result accuracy depends on the abilities of these models to represent real phenomenon. Vehicles models with 7 degrees of freedom (DOF), 10 DOF and 14 DOF are normally used in optimal control to solve for minimum lap time. However, suspension kinematics are always neglected on these models. Suspension kinematics are defined as wheel movements with respect to the vehicle body. Tire forces are expressed as a function of wheel slip and wheel position. Therefore, the suspension kinematic relation is appended to the 14 DOF vehicle model to investigate its effects on the accuracy of simulate trajectory. Classical 14 DOF vehicle model is chosen as baseline model. Experiment data is collected from formula student style car test runs as baseline data for simulation and comparison between baseline model and model with suspension kinematic. Results show that in a single long turn there is an accumulated trajectory error in baseline model compared to model with suspension kinematic. While in short alternate turns, the trajectory error is much smaller. These results show that suspension kinematic had an effect on the trajectory simulation of vehicle. Which optimal control that use baseline model will result in inaccuracy control scheme. 20. Temperature and emission-line structure at the edges of H II regions International Nuclear Information System (INIS) Mallik, D.C.V. 1975-01-01 Models of ionization fronts located at the edges of expanding H ii regions are presented. These fronts are of the weak D-type and are preceded by shocks in the H i clouds. Since the energy input time is smaller than the cooling time, the gas is found to heat up to a high temperature immediately following ionization. At the trailing edge of the front, the temperature decreases and the ionized gas merges with the main bulk of the nebula where the physical processes are in equilibrium. The emission in O ii and N ii lines is greatly enhanced because of the high temperature at the front. The emission in these and other important lines is calculated and compared with Hβ. Effects of different velocities of flow, of different exciting stars, and of different gas densities on the structure of the fronts are also investigated 1. Integrated-light spectroscopy of globular clusters at the infrared Ca II lines Science.gov (United States) Armandroff, Taft E.; Zinn, Robert 1988-01-01 Integrated-light spectroscopy has been obtained for 27 globular clusters at the Ca II IR triplet. Line strengths and radial velocities have been measured from the spectra. For the well-studied clusters in the sample, the strength of the Ca II lines is very well correlated with previous metallicity estimates. Thus, the triplet is useful as a metallicity indicator in globular cluster integrated-light spectra. The greatly reduced effect of interstellar extinction at these wavelengths (compared to the blue region of the spectrum) has permitted observations of some of the most heavily reddened clusters in the Galaxy. For several such clusters, the Ca II triplet metallicities are in poor agreement with metallicity estimates from IR photometry by Malkan (1981). The strength of an interstellar band at 8621A has been used to estimate the amount of extinction towards these clusters. Using the new metallicity and radial-velocity data, the metallicity distribution, kinematics, and spatial distribution of the disk globular cluster system have been analyzed. Results very similar to those of Zinn (1985) have been found. The relation of the disk globulars to the stellar thick disk is discussed. 2. Nonlinear kinematics for piezoelectricity in ALEGRA-EMMA. Energy Technology Data Exchange (ETDEWEB) Mitchell, John Anthony; Fuller, Timothy Jesse 2013-09-01 This report develops and documents nonlinear kinematic relations needed to implement piezoelectric constitutive models in ALEGRA-EMMA [5], where calculations involving large displacements and rotations are routine. Kinematic relationships are established using Gausss law and Faradays law; this presentation on kinematics goes beyond piezoelectric materials and is applicable to all dielectric materials. The report then turns to practical details of implementing piezoelectric models in an application code where material principal axes are rarely aligned with user defined problem coordinate axes. This portion of the report is somewhat pedagogical but is necessary in order to establish documentation for the piezoelectric implementation in ALEGRA-EMMA. This involves transforming elastic, piezoelectric, and permittivity moduli from material principal axes to problem coordinate axes. The report concludes with an overview of the piezoelectric implementation in ALEGRA-EMMA and small verification examples. 3. Nonlinear kinematic hardening under non-proportional loading International Nuclear Information System (INIS) Ottosen, N.S. 1979-07-01 Within the framework of conventional plasticity theory, it is first determined under which conditions Melan-Prager's and Ziegler's kinematic hardening rules result in identical material behaviour. Next, assuming initial isotropy and adopting the von Mises yield criterion, a nonlinear kinematic hardening function is proposed for prediction of metal behaviour. The model assumes that hardening at a specific stress point depends on the direction of the new incremental loading. Hereby a realistic response is obtained for general reversed loading, and a smooth behaviour is assured, even when loading deviates more and more from proportional loading and ultimately results in reversed loading. The predictions of the proposed model for non-proportional loading under plane stress conditions are compared with those of the classical linear kinematic model, the isotropic model and with published experimental data. Finally, the limitations of the proposaed model are discussed. (author) 4. Kinematic variables and water transport control the formation and location of arc volcanoes. Science.gov (United States) Grove, T L; Till, C B; Lev, E; Chatterjee, N; Médard, E 2009-06-04 The processes that give rise to arc magmas at convergent plate margins have long been a subject of scientific research and debate. A consensus has developed that the mantle wedge overlying the subducting slab and fluids and/or melts from the subducting slab itself are involved in the melting process. However, the role of kinematic variables such as slab dip and convergence rate in the formation of arc magmas is still unclear. The depth to the top of the subducting slab beneath volcanic arcs, usually approximately 110 +/- 20 km, was previously thought to be constant among arcs. Recent studies revealed that the depth of intermediate-depth earthquakes underneath volcanic arcs, presumably marking the slab-wedge interface, varies systematically between approximately 60 and 173 km and correlates with slab dip and convergence rate. Water-rich magmas (over 4-6 wt% H(2)O) are found in subduction zones with very different subduction parameters, including those with a shallow-dipping slab (north Japan), or steeply dipping slab (Marianas). Here we propose a simple model to address how kinematic parameters of plate subduction relate to the location of mantle melting at subduction zones. We demonstrate that the location of arc volcanoes is controlled by a combination of conditions: melting in the wedge is induced at the overlap of regions in the wedge that are hotter than the melting curve (solidus) of vapour-saturated peridotite and regions where hydrous minerals both in the wedge and in the subducting slab break down. These two limits for melt generation, when combined with the kinematic parameters of slab dip and convergence rate, provide independent constraints on the thermal structure of the wedge and accurately predict the location of mantle wedge melting and the position of arc volcanoes. 5. Specific degradation of 3' regions of GUS mRNA in posttranscriptionally silenced tobacco lines may be related to 5'-3' spreading of silencing DEFF Research Database (Denmark) Braunstein, Thomas Hartig; Moury, Benoit; Johannessen, Marina 2002-01-01 background, we have performed detailed analyses of target regions in three spontaneously beta-glucuronidase (GUS) silencing tobacco lines of different origin. From quantitative cosuppression experiments, we show that the main target region in all three tobacco lines is found within the 3' half of the GUS...... VIGS. Surprisingly, only evidence for spreading of the target region in the 5'-3' direction was obtained. This finding may help explain why the majority of target regions examined to date lie within the 3' region of transgenes.... 6. Of gluons and gravitons. Exploring color-kinematics duality International Nuclear Information System (INIS) Isermann, Reinke Sven 2013-06-01 In this thesis color-kinematics duality will be investigated. This duality is a statement about the kinematical dependence of a scattering amplitude in Yang-Mills gauge theories obeying group theoretical relations similar to that of the color gauge group. The major consequence of this duality is that gravity amplitudes can be related to a certain double copy of gauge theory amplitudes. The main focus of this thesis is on exploring the foundations of color-kinematics duality and its consequences. It is shown how color-kinematics duality can be made manifest at the one-loop level for rational amplitudes. A Lagrangian-based argument will be given for the validity of the double copy construction for these amplitudes including explicit examples at four points. Secondly, it is studied how color-kinematics duality can be used to improve powercounting in gravity theories. To this end the duality is reformulated in terms of linear maps. It is shown as an example how this can be used to derive the large BCFW shift behavior of a gravity integrand constructed through the duality to any loop order up to subtleties inherent to the duality that is addressed. As it becomes clear the duality implies massive cancellations with respect to the usual powercounting of Feynman graphs indicating that gravity theories are much better behaved than naively expected. As another example the linear map approach will be used to investigate the question of UV-finiteness of N=8 supergravity, and it is seen that the amount of cancellations depends on the exact implementation of the duality at loop level. Lastly, color-kinematics duality is considered from a Feynman-graph perspective reproducing some of the results of the earlier chapters thus giving non-trivial evidence for the duality at the loop level from a different perspective. 7. Of gluons and gravitons. Exploring color-kinematics duality Energy Technology Data Exchange (ETDEWEB) Isermann, Reinke Sven 2013-06-15 In this thesis color-kinematics duality will be investigated. This duality is a statement about the kinematical dependence of a scattering amplitude in Yang-Mills gauge theories obeying group theoretical relations similar to that of the color gauge group. The major consequence of this duality is that gravity amplitudes can be related to a certain double copy of gauge theory amplitudes. The main focus of this thesis is on exploring the foundations of color-kinematics duality and its consequences. It is shown how color-kinematics duality can be made manifest at the one-loop level for rational amplitudes. A Lagrangian-based argument will be given for the validity of the double copy construction for these amplitudes including explicit examples at four points. Secondly, it is studied how color-kinematics duality can be used to improve powercounting in gravity theories. To this end the duality is reformulated in terms of linear maps. It is shown as an example how this can be used to derive the large BCFW shift behavior of a gravity integrand constructed through the duality to any loop order up to subtleties inherent to the duality that is addressed. As it becomes clear the duality implies massive cancellations with respect to the usual powercounting of Feynman graphs indicating that gravity theories are much better behaved than naively expected. As another example the linear map approach will be used to investigate the question of UV-finiteness of N=8 supergravity, and it is seen that the amount of cancellations depends on the exact implementation of the duality at loop level. Lastly, color-kinematics duality is considered from a Feynman-graph perspective reproducing some of the results of the earlier chapters thus giving non-trivial evidence for the duality at the loop level from a different perspective. 8. The complex jet- and bar-perturbed kinematics in NGC 3393 as revealed with ALMA and GEMINI-GMOS/IFU Science.gov (United States) Finlez, Carolina; Nagar, Neil M.; Storchi-Bergmann, Thaisa; Schnorr-Müller, Allan; Riffel, Rogemar A.; Lena, Davide; Mundell, C. G.; Elvis, Martin S. 2018-06-01 NGC 3393, a nearby Seyfert 2 galaxy with nuclear radio jets, large-scale and nuclear bars, and a posited secondary super massive black hole, provides an interesting laboratory to test the physics of inflows and outflows. Here we present and analyse the molecular gas (ALMA observations of CO J:2-1 emission over a field of view (FOV) of 45" × 45", at 0."56 (143 pc) spatial and 5 km/s spectral resolution), ionised gas and stars (GEMINI-GMOS/IFU; over a FOV of 4" × 5", at 0."62 (159 pc) spatial and 23 km/s spectral resolution) in NGC 3393. The ionised gas emission, detected over the complete GEMINI-GMOS FOV, has three identifiable kinematic components. A narrow (σ 115 km/s) redshifted component, detected near the NE and SW radio lobes; which we interpret as a radio jet driven outflow. And a broad (σ > 115 km/s) blueshifted component that shows high velocities in a region perpendicular to the radio jet axis; we interpret this as an equatorial outflow. The CO J:2-1 emission is detected in spiral arms on 5" - 20" scales, and in two disturbed circumnuclear regions. The molecular kinematics in the spiral arms can be explained by rotation. The highly disturbed kinematics of the inner region can be explained by perturbations induced by the nuclear bar and interactions with the large scale bar. We find no evidence for, but cannot strongly rule out, the presence of the posited secondary black hole. 9. Forward and inverse kinematics of double universal joint robot wrists Science.gov (United States) Williams, Robert L., II 1991-01-01 A robot wrist consisting of two universal joints can eliminate the wrist singularity problem found on many individual robots. Forward and inverse position and velocity kinematics are presented for such a wrist having three degrees of freedom. Denavit-Hartenberg parameters are derived to find the transforms required for the kinematic equations. The Omni-Wrist, a commercial double universal joint robot wrist, is studied in detail. There are four levels of kinematic parameters identified for this wrist; three forward and three inverse maps are presented for both position and velocity. These equations relate the hand coordinate frame to the wrist base frame. They are sufficient for control of the wrist standing alone. When the wrist is attached to a manipulator arm; the offset between the two universal joints complicates the solution of the overall kinematics problem. All wrist coordinate frame origins are not coincident, which prevents decoupling of position and orientation for manipulator inverse kinematics. 10. Kinematic analysis of competitive sprinting | Ansari | African Journal ... African Journals Online (AJOL) The results of the study showed that the kinematic variables i.e. knee angle, hip angle, ankle angle, shoulder rotation and extension had a significant influence on sprinting style. The results indicated that the kinematic variables of running style, knee angle at landing, hip flexion, ankle angle at landing, ankle angle at take-off, ... 11. Inverse kinematic control of LDUA and TWRMS International Nuclear Information System (INIS) Yih, T.C.; Burks, B.L.; Kwon, Dong-Soo 1995-01-01 A general inverse kinematic analysis is formulated particularly for the redundant Light Duty Utility Arm (LDUA) and Tank Waste Retrieval Manipulator System (TWRMS). The developed approach is applicable to the inverse kinematic simulation and control of LDUA, TWRMS, and other general robot manipulators. The 4 x 4 homogeneous Cylindrical coordinates-Bryant angles (C-B) notation is adopted to model LDUA, TWRMS, and any robot composed of R (revolute), P (prismatic), and/or S (spherical) joints 12. Dynamic Control of Kinematically Redundant Robotic Manipulators Directory of Open Access Journals (Sweden) Erling Lunde 1987-07-01 Full Text Available Several methods for task space control of kinematically redundant manipulators have been proposed in the literature. Most of these methods are based on a kinematic analysis of the manipulator. In this paper we propose a control algorithm in which we are especially concerned with the manipulator dynamics. The algorithm is particularly well suited for the class of redundant manipulators consisting of a relatively small manipulator mounted on a larger positioning part. 13. Scapula Kinematics of Youth Baseball Players Directory of Open Access Journals (Sweden) Oliver Gretchen 2015-12-01 Full Text Available Literature has revealed the importance of quantifying resting scapular posture in overhead athletes as well as quantifying scapular kinematics during dynamic movement. Prior to this project much of the attention in throwing research had been focused on the position of the humerus without description of the positioning of the scapula. Therefore, it was the purpose of this study to present scapular kinematics during pitching in youth baseball players. Twenty-five youth baseball players (age 11.3 + 1.0 years; body height 152.4 + 9.0 cm; body mass 47.5 + 11.3 kg, with no history of injury, participated in the study. Scapular kinematics at the events of maximum humeral external rotation (MER and maximum humeral internal rotation (MIR during the pitching motion were assessed three-dimensionally while pitching fastballs for strikes. Results revealed that at the event of MER, the scapula was in a position of retraction, upward rotation and a posterior tilt. While at the event of MIR, the scapula was protracted, upward rotated and tilted anteriorly. 14. Tune-shift with amplitude due to nonlinear kinematic effect CERN Document Server Wan, W 1999-01-01 Tracking studies of the Muon Collider 50 on 50 GeV collider ring show that the on-momentum dynamic aperture is limited to around 10 sigma even with the chromaticity sextupoles turned off. Numerical results from the normal form algorithm show that the tune-shift with amplitude is surprisingly large. Both analytical and numerical results are presented to show that nonlinear kinematic effect originated from the large angles of particles in the interaction region is responsible for the large tune-shift which in turn limits the dynamic aperture. A comparative study of the LHC collider ring is also presented to demonstrate the difference between the two machines. (14 refs). 15. PHYSICAL CONDITIONS IN THE INNER NARROW-LINE REGION OF THE SEYFERT 2 GALAXY MARKARIAN 573 International Nuclear Information System (INIS) Kraemer, S. B.; Trippe, M. L.; Crenshaw, D. M.; Fischer, T. C.; Melendez, M.; Schmitt, H. R. 2009-01-01 We have examined the physical conditions within a bright emission-line knot in the inner narrow-line region (NLR) of the Seyfert 2 galaxy Mrk 573 using optical spectra and photoionization models. The spectra were obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph, through the 0.''2 x 52.''0 slit, at a position angle of -71. 0 2, with the G430L and G750M gratings. Comparing the spatial emission-line profiles, we found [Fe X] λ 6734 barely resolved, [O III] λ5007 centrally peaked, but broader than [Fe X], and [O II] λ3727 the most extended. Spectra of the central knot were extracted from a region 1.''1 in extent, corresponding to the full width at zero intensity in the cross-dispersion direction, of the knot. The spectra reveal that [Fe X] is broader in velocity width and blueshifted compared with lines from less ionized species. Our estimate of the bolometric luminosity indicates that the active galactic nucleus (AGN) is radiating at or above its Eddington luminosity, which is consistent with its identification as a hidden Narrow-Line Seyfert 1. We were able to successfully match the observed emission-line ratios with a three-component photoionization model. Two components, one to account for the [O III] emission and another in which the [Fe X] arises, are directly ionized by the AGN, while [O II] forms in a third component, which is ionized by a heavily absorbed continuum. Based on our assumed ionizing continuum and the model parameters, we determined that the two directly ionized components are ∼55 pc from the AGN. We have found similar radial distances for the central knots in the Seyfert 2 galaxies Mrk 3 and NGC 1068, but much smaller radial distances for the inner NLR in the Seyfert 1 galaxies NGC 4151 and NGC 5548. Although in general agreement with the unified model, these results suggest that the obscuring material in Seyfert galaxies extends out to at least tens of parsecs from the AGN. 16. Gas dynamics in the inner few AU around the Herbig B[e] star MWC297. Indications of a disk wind from kinematic modeling and velocity-resolved interferometric imaging Science.gov (United States) Hone, Edward; Kraus, Stefan; Kreplin, Alexander; Hofmann, Karl-Heinz; Weigelt, Gerd; Harries, Tim; Kluska, Jacques 2017-10-01 Aims: Circumstellar accretion disks and outflows play an important role in star formation. By studying the continuum and Brγ-emitting region of the Herbig B[e] star MWC297 with high-spectral and high-spatial resolution we aim to gain insight into the wind-launching mechanisms in young stars. Methods: We present near-infrared AMBER (R = 12 000) and CRIRES (R = 100 000) observations of the Herbig B[e] star MWC297 in the hydrogen Brγ-line. Using the VLTI unit telescopes, we obtained a uv-coverage suitable for aperture synthesis imaging. We interpret our velocity-resolved images as well as the derived two-dimensional photocenter displacement vectors, and fit kinematic models to our visibility and phase data in order to constrain the gas velocity field on sub-AU scales. Results: The measured continuum visibilities constrain the orientation of the near-infrared-emitting dust disk, where we determine that the disk major axis is oriented along a position angle of 99.6 ± 4.8°. The near-infrared continuum emission is 3.6 × more compact than the expected dust-sublimation radius, possibly indicating the presence of highly refractory dust grains or optically thick gas emission in the inner disk. Our velocity-resolved channel maps and moment maps reveal the motion of the Brγ-emitting gas in six velocity channels, marking the first time that kinematic effects in the sub-AU inner regions of a protoplanetary disk could be directly imaged. We find a rotation-dominated velocity field, where the blue- and red-shifted emissions are displaced along a position angle of 24° ± 3° and the approaching part of the disk is offset west of the star. The visibility drop in the line as well as the strong non-zero phase signals can be modeled reasonably well assuming a Keplerian velocity field, although this model is not able to explain the 3σ difference that we measure between the position angle of the line photocenters and the position angle of the dust disk. We find that the fit can be 17. Numerical simulation of mesoscale surface pressure features with trailing stratiform squall lines using WRF -ARW model over Gangetic West Bengal region Science.gov (United States) Dawn, Soma; Satyanarayana, A. N. V. 2018-01-01 In the present study, an attempt has been made to investigate the simulation of mesoscale surface pressure patterns like pre-squall mesolow, mesohigh and wake low associated with leading convective line-trailing stratiform (TS) squall lines over Gangetic West Bengal (GWB). For this purpose, a two way interactive triple nested domain with high resolution WRF model having2 km grid length in the innermost domain is used. The model simulated results are compared with the available in-situ observations obtained as a part of Severe Thunderstorm: Observations and Regional Modeling (STORM) programme, reflectivity products of Doppler Weather Radar (DWR) Kolkata and TRMM rainfall. Three TS squall lines (15 May 2009, 5 May 2010 and 7 May 2010) are chosen during pre-monsoon thunderstorm season for this study. The model simulated results of diurnal variation of temperature, relative humidity, wind speed and direction at the station Kharagpur in GWB region reveal a sudden fall in temperature, increase in the amount of relative humidity and sudden rise in wind speed during the arrival of the storms. Such results are well comparable with the observations though there are some leading or lagging of time in respect of actual occurrences of such events. The study indicates that the model is able to predict the occurrences of three typical surface pressure features namely: pre-squall mesolow, meso high and wake low. The predicted surface parameters like accumulated rainfall, maximum reflectivity and vertical profiles (temperature, relative humidity and winds) are well accorded with the observations. The convective and stratiform precipitation region of the TS squall lines are well represented by the model. A strong downdraft is observed to be a contributory factor for formation of mesohigh in the convective region of the squall line. Wake low is observed to reside in the stratiform rain region and the descending dry air at this place has triggered the wake low through adiabatic 18. Rigid-body kinematics versus flapping kinematics of a flapping wing micro air vehicle NARCIS (Netherlands) Caetano, J.V.; Weehuizen, M.B.; De Visser, C.C.; De Croon, G.C.H.E.; Mulder, M. 2015-01-01 Several formulations have been proposed to model the dynamics of ornithopters, with inconclusive results regarding the need for complex kinematic formulations. Furthermore, the impact of assumptions made in the collected results was never assessed by comparing simulations with real flight data. In 19. Global-local optimization of flapping kinematics in hovering flight KAUST Repository Ghommem, Mehdi; Hajj, M. R.; Mook, Dean T.; Stanford, Bret K.; Bé ran, Philip S.; Watson, Layne T. 2013-01-01 The kinematics of a hovering wing are optimized by combining the 2-d unsteady vortex lattice method with a hybrid of global and local optimization algorithms. The objective is to minimize the required aerodynamic power under a lift constraint. The hybrid optimization is used to efficiently navigate the complex design space due to wing-wake interference present in hovering aerodynamics. The flapping wing is chosen so that its chord length and flapping frequency match the morphological and flight properties of two insects with different masses. The results suggest that imposing a delay between the different oscillatory motions defining the flapping kinematics, and controlling the way through which the wing rotates at the end of each half stroke can improve aerodynamic power under a lift constraint. Furthermore, our optimization analysis identified optimal kinematics that agree fairly well with observed insect kinematics, as well as previously published numerical results. 20. Global-local optimization of flapping kinematics in hovering flight KAUST Repository Ghommem, Mehdi 2013-06-01 The kinematics of a hovering wing are optimized by combining the 2-d unsteady vortex lattice method with a hybrid of global and local optimization algorithms. The objective is to minimize the required aerodynamic power under a lift constraint. The hybrid optimization is used to efficiently navigate the complex design space due to wing-wake interference present in hovering aerodynamics. The flapping wing is chosen so that its chord length and flapping frequency match the morphological and flight properties of two insects with different masses. The results suggest that imposing a delay between the different oscillatory motions defining the flapping kinematics, and controlling the way through which the wing rotates at the end of each half stroke can improve aerodynamic power under a lift constraint. Furthermore, our optimization analysis identified optimal kinematics that agree fairly well with observed insect kinematics, as well as previously published numerical results. 1. Overground-Propulsion Kinematics and Acceleration in Elite Wheelchair Rugby. Science.gov (United States) Haydon, David S; Pinder, Ross A; Grimshaw, Paul N; Robertson, William S P 2018-02-01 Maximal acceleration from standstill has been identified as a key performance indicator in wheelchair rugby; however, the impact of classification and kinematic variables on performance has received limited attention. This study aimed to investigate kinematic variables during maximal acceleration, with level of activity limitation accounted for using sport-classification scores. Based on their sporting classification scores, which reflect combined trunk, arm, and hand function, 25 elite wheelchair rugby players were analyzed in high-, mid-, and low-point groups before completing five 5-m sprints from a stationary position. Inertial measurement units and video analysis were used to monitor key kinematic variables. Significant differences in kinematic variables were evident across the classification groups, particularly for the first stroke-contact angle (1-way ANOVA F 2,122 = 51.5, P propulsion approaches exist across classification groups, with this information potentially informing individual wheelchair setups and training programs. 2. Kinematic gait analyses in healthy Golden Retrievers OpenAIRE Silva, Gabriela C.A.; Cardoso, Mariana Trés; Gaiad, Thais P.; Brolio, Marina P.; Oliveira, Vanessa C.; Assis Neto, Antonio; Martins, Daniele S.; Ambrósio, Carlos E. 2014-01-01 Kinematic analysis relates to the relative movement between rigid bodies and finds application in gait analysis and other body movements, interpretation of their data when there is change, determines the choice of treatment to be instituted. The objective of this study was to standardize the march of Dog Golden Retriever Healthy to assist in the diagnosis and treatment of musculoskeletal disorders. We used a kinematic analysis system to analyse the gait of seven dogs Golden Retriever, female,... 3. Kinematics and Dynamics of Roller Chain Drives DEFF Research Database (Denmark) Fuglede, Niels There are two main subjects of this work: Kinematic and dynamic modeling and analysis of roller chain drives. In the kinematic analysis we contribute first with a complete treatment of the roller chain drive modeled as a four-bar mechanism. This includes a general, exact and approximate analysis...... which is useful for predicting the characteristic loading of the roller chain drive. As a completely novel contribution, a kinematic model and analysis is presented which includes both spans and sprockets in a simple chain drive system. A general procedure for determination of the total wrapping length...... is presented, which also allows for exact sprocket center positions for a chain with a given number of links. Results show that the total chain wrapping length varies periodically with the tooth frequency. These results are of practical importance to both the design, installation and operation of roller chain... 4. Probabilistic approach to manipulator kinematics and dynamics International Nuclear Information System (INIS) Rao, S.S.; Bhatti, P.K. 2001-01-01 A high performance, high speed robotic arm must be able to manipulate objects with a high degree of accuracy and repeatability. As with any other physical system, there are a number of factors causing uncertainties in the behavior of a robotic manipulator. These factors include manufacturing and assembling tolerances, and errors in the joint actuators and controllers. In order to study the effect of these uncertainties on the robotic end-effector and to obtain a better insight into the manipulator behavior, the manipulator kinematics and dynamics are modeled using a probabilistic approach. Based on the probabilistic model, kinematic and dynamic performance criteria are defined to provide measures of the behavior of the robotic end-effector. Techniques are presented to compute the kinematic and dynamic reliabilities of the manipulator. The effects of tolerances associated with the various manipulator parameters on the reliabilities are studied. Numerical examples are presented to illustrate the procedures 5. Kinematic Optimization in Birds, Bats and Ornithopters Science.gov (United States) Reichert, Todd Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice. 6. Kinematics and design of a class of parallel manipulators Science.gov (United States) Hertz, Roger Barry 1998-12-01 This dissertation is concerned with the kinematic analysis and design of a class of three degree-of-freedom, spatial parallel manipulators. The class of manipulators is characterized by two platforms, between which are three legs, each possessing a succession of revolute, spherical, and revolute joints. The class is termed the "revolute-spherical-revolute" class of parallel manipulators. Two members of this class are examined. The first mechanism is a double-octahedral variable-geometry truss, and the second is termed a double tripod. The history the mechanisms is explored---the variable-geometry truss dates back to 1984, while predecessors of the double tripod mechanism date back to 1869. This work centers on the displacement analysis of these three-degree-of-freedom mechanisms. Two types of problem are solved: the forward displacement analysis (forward kinematics) and the inverse displacement analysis (inverse kinematics). The kinematic model of the class of mechanism is general in nature. A classification scheme for the revolute-spherical-revolute class of mechanism is introduced, which uses dominant geometric features to group designs into 8 different sub-classes. The forward kinematics problem is discussed: given a set of independently controllable input variables, solve for the relative position and orientation between the two platforms. For the variable-geometry truss, the controllable input variables are assumed to be the linear (prismatic) joints. For the double tripod, the controllable input variables are the three revolute joints adjacent to the base (proximal) platform. Multiple solutions are presented to the forward kinematics problem, indicating that there are many different positions (assemblies) that the manipulator can assume with equivalent inputs. For the double tripod these solutions can be expressed as a 16th degree polynomial in one unknown, while for the variable-geometry truss there exist two 16th degree polynomials, giving rise to 256 7. Photoionization Models of the H_2 Emission of the Narrow Line Region of AGNs Science.gov (United States) Aleman, I.; Gruenwald, R. 2011-05-01 The excitation mechanism of the narrow line region (NLR) of AGNs is still an open question. Excitation by UV radiation from O and B stars, x-rays from the central black hole, shock from supernovae or jets, or a combination of these mechanisms have been suggested. In the present work, we use photoionization models to study the excitation mechanisms of the H_2 infrared emission lines in the NLR. In the literature, analyzes of the H_2 emission have been done assuming that the molecules is present only in neutral regions (photodissociation regions, x-ray-dominated regions, or shocks; Veilleux et al. 1997, Krabbe et al. 2000, Rigopoulou et al. 2002, Rodriguez-Ardila et al. 2004, 2005, and Davies et al. 2005). However, they are not conclusive. In previous work (Aleman & Gruenwald 2004, 2011), we show that the H_2 emission from the ionized region of PNe can be significant for planetary nebulae (PNe) with hot central stars (T⋆ > 150000 K). Such stars produce copious amounts of high energy photons, which create an extended partially ionized region that favors the H_2 survival. The conditions in the NLR are similar to those in PNe with hot central stars, so we can expect that the H_2 emission might also be important. We obtain and analyze a grid of photoionization models for different NRL parameters. We study the resulting H_2 density and emission, as well as, the formation, destruction, excitation, and de-excitation mechanisms. The higher values observed for the H_2 1-0 S(1)/Brγ ratio cannot be reproduced by our models. The calculated ratios are between 10^-8 and 10^-1, while the observational ration can be as high as 10. The calculated ratio is strongly anti-correlated with the ionization parameter (U) and only models with U<10-3 result in ratios inside the observational range. We show that the NLR is an environment more hostile to the H_2 molecule than the ionized region of PNe. Another interesting result of our calculations is that the H_2 formation on grain surfaces 8. Chemical composition of stars in kinematical substructures of the galactic disk Directory of Open Access Journals (Sweden) Gorbaneva T.I. 2012-02-01 Full Text Available The Y, Zr, La, Ce, Nd , Sm and Eu abundances were found in LTE approach, and the abundance of Ba was computed in NLTE approximation for 280 FGK dwarfs in the region of metallicity of − 1<[Fe]< + 0.3. The selection of stars belonging to thin and thick disks and the stream Hercules was made on kinematic criteria. The analysis of enrichment of the different substructures of the Galaxy with α-element (Mg, Si, the iron peak (Ni and neutron-capture elements was carried out. 9. High energy production of gluons in a quasi-multi-Regge kinematics International Nuclear Information System (INIS) Fadin, V.S.; Lipatov, L.N. 1989-01-01 Inelastic gluon-gluon scattering amplitudes in the Born approximation for the quasi-multi-Regge kinematics are calculated, starting with the Veneziano-type expression for the inelastic amplitude of the gluon-tachyon scattering with its subsequent simplification in the region of large energies and the Regge slope α'→0. Results obtained allow one to determine the high order corrections to the gluon Regge trajectory, the reggeon-particle vertices and to the integral kernel of the Bethe-Salpeter equation for the vacuum t-channel partial waves. 10 refs.; 7 figs 10. The Gould's Belt Distances Survey (GOBELINS). IV. Distance, Depth, and Kinematics of the Taurus Star-forming Region Science.gov (United States) Galli, Phillip A. B.; Loinard, Laurent; Ortiz-Léon, Gisela N.; Kounkel, Marina; Dzib, Sergio A.; Mioduszewski, Amy J.; Rodríguez, Luis F.; Hartmann, Lee; Teixeira, Ramachrisna; Torres, Rosa M.; Rivera, Juana L.; Boden, Andrew F.; Evans, Neal J., II; Briceño, Cesar; Tobin, John J.; Heyer, Mark 2018-05-01 We present new trigonometric parallaxes and proper motions of young stellar objects in the Taurus molecular cloud complex from observations collected with the Very Long Baseline Array as part of the Gould’s Belt Distances Survey. We detected 26 young stellar objects and derived trigonometric parallaxes for 18 stars with an accuracy of 0.3% to a few percent. We modeled the orbits of six binaries and determined the dynamical masses of the individual components in four of these systems (V1023 Tau, T Tau S, V807 Tau, and V1000 Tau). Our results are consistent with the first trigonometric parallaxes delivered by the Gaia satellite and reveal the existence of significant depth effects. We find that the central portion of the dark cloud Lynds 1495 is located at d =129.5 ± 0.3 pc, while the B216 clump in the filamentary structure connected to it is at d = 158.1 ± 1.2 pc. The closest and remotest stars in our sample are located at d = 126.6 ± 1.7 pc and d = 162.7 ± 0.8 pc, yielding a distance difference of about 36 pc. We also provide a new distance estimate for HL Tau that was recently imaged. Finally, we compute the spatial velocity of the stars with published radial velocity and investigate the kinematic properties of the various clouds and gas structures in this region. 11. Cluster algebras in scattering amplitudes with special 2D kinematics Energy Technology Data Exchange (ETDEWEB) Torres, Marcus A.C. [Institut de Physique Theorique, CEA-Saclay, Gif-sur-Yvette Cedex (France) 2014-02-15 We study the cluster algebra of the kinematic configuration space Conf{sub n}(P{sup 3}P3) of an n-particle scattering amplitude restricted to the special 2D kinematics. We found that the n-point two-loop MHVremainder function in special 2D kinematics depends on a selection of the X-coordinates that are part of a special structure of the cluster algebra related to snake triangulations of polygons. This structure forms a necklace of hypercube beads in the corresponding Stasheff polytope. Furthermore at n = 12, the cluster algebra and the selection of theX-coordinates in special2Dkinematics replicates the cluster algebra and the selection of X-coordinates of the n = 6 two-loop MHV amplitude in 4D kinematics. (orig.) 12. A model for consecutive spallation and fragmentation reactions in inverse kinematics at relativistic energies International Nuclear Information System (INIS) Napolitani, P.; Tassan-Got, L.; Bernas, M.; Armbruster, P. 2003-04-01 Secondary reactions induced by relativistic beams in inverse kinematics in a thick target are relevant in several fields of experimental physics and technology, like secondary radioactive beams, production of exotic nuclei close to the proton drip line, and cross-section measurements for applications of spallation reactions for energy production and incineration of nuclear wastes. A general mathematical formulation is presented and successively applied as a tool to disentangle the primary reaction yields from the secondary production in the measurement of fission of a 238 U projectile impinging on a proton target at the energy of 1 A GeV. (orig.) 13. ACCRETION KINEMATICS THROUGH THE WARPED TRANSITION DISK IN HD 142527 FROM RESOLVED CO(6–5) OBSERVATIONS Energy Technology Data Exchange (ETDEWEB) Casassus, S.; Marino, S.; Pérez, S.; Plas, G. van der; Christiaens, V.; Montesinos, Matías [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Roman, P.; Dunhill, A.; Cuadra, J.; Cieza, L.; Moral, Victor [Millennium Nucleus “Protoplanetary Disks,” Chile (Chile); Armitage, P. J. [JILA, University of Colorado and NIST, UCB 440, Boulder, CO 80309 (United States); Wootten, A., E-mail: scasassus@u.uchile.cl [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States) 2015-10-01 The finding of residual gas in the large central cavity of the HD 142527 disk motivates questions regarding the origin of its non-Keplerian kinematics and possible connections with planet formation. We aim to understand the physical structure that underlies the intra-cavity gaseous flows, guided by new molecular-line data in CO(6–5) with unprecedented angular resolutions. Given the warped structure inferred from the identification of scattered-light shadows cast on the outer disk, the kinematics are consistent, to first order, with axisymmetric accretion onto the inner disk occurring at all azimuths. A steady-state accretion profile, fixed at the stellar accretion rate, explains the depth of the cavity as traced in CO isotopologues. The abrupt warp and evidence for near free-fall radial flows in HD 142527 resemble theoretical models for disk tearing, which could be driven by the reported low-mass companion, whose orbit may be contained in the plane of the inner disk. The companion’s high inclination with respect to the massive outer disk could drive Kozai oscillations over long timescales; high-eccentricity periods may perhaps account for the large cavity. While shadowing by the tilted disk could imprint an azimuthal modulation in the molecular-line maps, further observations are required to ascertain the significance of azimuthal structure in the density field inside the cavity of HD 142527. 14. Kinematics and Workspace of a 4-DOF Hybrid Palletizing Robot Directory of Open Access Journals (Sweden) Yong Tao 2014-06-01 Full Text Available We presented the kinematical analysis of a 4-DOF hybrid palletizing robot. The palletizing robot structure was proposed and the arm model of the robot was presented. The kinematical analysis of the end robotic manipulator was given. As a result, the position, velocity, and acceleration curves as well as the maximum workspace were demonstrated by simulation in Matlab. This study would be useful for the kinematical characteristics of the 4-DOF palletizing robot in space. 15. PROBING THE PHYSICS OF NARROW LINE REGIONS IN ACTIVE GALAXIES. II. THE SIDING SPRING SOUTHERN SEYFERT SPECTROSCOPIC SNAPSHOT SURVEY (S7) Energy Technology Data Exchange (ETDEWEB) Dopita, Michael A.; Davies, Rebecca; Kewley, Lisa; Hampton, Elise; Sutherland, Ralph [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Shastri, Prajval; Kharb, Preeti; Jose, Jessy; Bhatt, Harish; Ramya, S. [Indian Institute of Astrophysics, Koramangala 2 B Block, Bangalore 560034 (India); Scharwächter, Julia [LERMA, Observatoire de Paris, CNRS, UMR 8112, 61 Avenue de l’Observatoire, F-75014 Paris (France); Jin, Chichuan [Qian Xuesen Laboratory for Space Technology, Beijing (China); Banfield, Julie [CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW, 1710 Australia (Australia); Zaw, Ingyin [New York University (Abu Dhabi), 70 Washington Square South, New York, NY 10012 (United States); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); James, Bethan [Institute of Astronomy, Cambridge University, Madingley Road, Cambridge CB3 0HA (United Kingdom); Srivastava, Shweta, E-mail: Michael.Dopita@anu.edu.au [Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009 (India) 2015-03-15 Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph mounted on the ANU 2.3 m telescope located at the Siding Spring Observatory to deliver an integral field of 38 × 25 arcsec at a spectral resolution of R = 7000 in the red (530–710 nm), and R = 3000 in the blue (340–560 nm). From these data cubes we have extracted the narrow-line region spectra from a 4 arcsec aperture centered on the nucleus. We also determine the Hβ and [O iii] λ5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the Hβ and [O iii] λ5007 luminosities determined from spectra for which the stellar continuum has been removed. We present a set of images of the galaxies in [O iii] λ5007, [N ii] λ6584, and Hα, which serve to delineate the spatial extent of the extended narrow-line region and also to reveal the structure and morphology of the surrounding H ii regions. Finally, we provide a preliminary discussion of those Seyfert 1 and Seyfert 2 galaxies that display coronal emission lines in order to explore the origin of these lines. 16. A Closed Loop Inverse Kinematics Solver Intended for Offline Calculation Optimized with GA Directory of Open Access Journals (Sweden) Emil Dale Bjoerlykhaug 2018-01-01 Full Text Available This paper presents a simple approach to building a robotic control system. Instead of a conventional control system which solves the inverse kinematics in real-time as the robot moves, an alternative approach where the inverse kinematics is calculated ahead of time is presented. This approach reduces the complexity and code necessary for the control system. Robot control systems are usually implemented in low level programming language. This new approach enables the use of high level programming for the complex inverse kinematics problem. For our approach, we implement a program to solve the inverse kinematics, called the Inverse Kinematics Solver (IKS, in Java, with a simple graphical user interface (GUI to load a file with desired end effector poses and edit the configuration of the robot using the Denavit-Hartenberg (DH convention. The program uses the closed-loop inverse kinematics (CLIK algorithm to solve the inverse kinematics problem. As an example, the IKS was set up to solve the kinematics for a custom built serial link robot. The kinematics for the custom robot is presented, and an example of input and output files is also presented. Additionally, the gain of the loop in the IKS is optimized using a GA, resulting in almost a 50% decrease in computational time. 17. Engine cylinder pressure reconstruction using crank kinematics and recurrently-trained neural networks Science.gov (United States) Bennett, C.; Dunne, J. F.; Trimby, S.; Richardson, D. 2017-02-01 A recurrent non-linear autoregressive with exogenous input (NARX) neural network is proposed, and a suitable fully-recurrent training methodology is adapted and tuned, for reconstructing cylinder pressure in multi-cylinder IC engines using measured crank kinematics. This type of indirect sensing is important for cost effective closed-loop combustion control and for On-Board Diagnostics. The challenge addressed is to accurately predict cylinder pressure traces within the cycle under generalisation conditions: i.e. using data not previously seen by the network during training. This involves direct construction and calibration of a suitable inverse crank dynamic model, which owing to singular behaviour at top-dead-centre (TDC), has proved difficult via physical model construction, calibration, and inversion. The NARX architecture is specialised and adapted to cylinder pressure reconstruction, using a fully-recurrent training methodology which is needed because the alternatives are too slow and unreliable for practical network training on production engines. The fully-recurrent Robust Adaptive Gradient Descent (RAGD) algorithm, is tuned initially using synthesised crank kinematics, and then tested on real engine data to assess the reconstruction capability. Real data is obtained from a 1.125 l, 3-cylinder, in-line, direct injection spark ignition (DISI) engine involving synchronised measurements of crank kinematics and cylinder pressure across a range of steady-state speed and load conditions. The paper shows that a RAGD-trained NARX network using both crank velocity and crank acceleration as input information, provides fast and robust training. By using the optimum epoch identified during RAGD training, acceptably accurate cylinder pressures, and especially accurate location-of-peak-pressure, can be reconstructed robustly under generalisation conditions, making it the most practical NARX configuration and recurrent training methodology for use on production engines. 18. Spinal kinematics during smartphone texting - A comparison between young adults with and without chronic neck-shoulder pain. Science.gov (United States) Xie, Yan Fei; Szeto, Grace; Madeleine, Pascal; Tsang, Sharon 2018-04-01 To advance our understanding about the association between smartphone use and chronic neck-shoulder pain, the objective of this study was to compare spinal kinematics between different text-entry methods in smartphone users with and without chronic neck-shoulder pain. Symptomatic (n = 19) and healthy participants (n = 18) were recruited and they performed three tasks: texting on a smartphone with one hand, with two hands, and typing on a desktop computer. Three-dimensional kinematics were examined in the cervical, thoracic and lumbar regions for each task. This study suggests that altered kinematics may be associated with pain since significantly increased angles of cervical right side flexion during smartphone texting and greater postural changes in cervical rotation were found during all text-entry tasks in the symptomatic group. Two-handed texting was associated with increased cervical flexion while one-handed texting was correlated with an asymmetric neck posture, indicating both text-entry methods are not favorable in terms of spinal postures. Copyright © 2017 Elsevier Ltd. All rights reserved. 19. Understanding the central kinematics of globular clusters with simulated integrated-light IFU observations Science.gov (United States) Bianchini, Paolo; Norris, Mark A.; van de Ven, Glenn; Schinnerer, Eva 2015-10-01 The detection of intermediate-mass black holes in the centres of globular clusters is highly controversial, as complementary observational methods often deliver significantly different results. In order to understand these discrepancies, we develop a procedure to simulate integral field unit (IFU) observations of globular clusters: Simulating IFU Star Cluster Observations (SISCO). The inputs of our software are realistic dynamical models of globular clusters that are then converted in a spectral data cube. We apply SISCO to Monte Carlo cluster simulations with a realistic number of stars and concentrations. Using independent realizations of a given simulation we are able to quantify the stochasticity intrinsic to the problem of observing a partially resolved stellar population with integrated-light spectroscopy. We show that the luminosity-weighted IFU observations can be strongly biased by the presence of a few bright stars that introduce a scatter in the velocity dispersion measurements up to ≃40 per cent around the expected value, preventing any sound assessment of the central kinematic and a sensible interpretation of the presence/absence of an intermediate-mass black hole. Moreover, we illustrate that, in our mock IFU observations, the average kinematic tracer has a mass of ≃0.75 M⊙, only slightly lower than the mass of the typical stars examined in studies of resolved line-of-sight velocities of giant stars. Finally, in order to recover unbiased kinematic measurements we test different masking techniques that allow us to remove the spaxels dominated by bright stars, bringing the scatter down to a level of only a few per cent. The application of SISCO will allow us to investigate state-of-the-art simulations as realistic observations. 20. Kinematics of the Optically Visible YSOs toward the Orion B Molecular Cloud Energy Technology Data Exchange (ETDEWEB) Kounkel, Marina; Hartmann, Lee; Mateo, Mario [Department of Astronomy, University of Michigan, 1085 S. University Street, Ann Arbor, MI 48109 (United States); Bailey, John I. III, E-mail: mkounkel@umich.edu [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands) 2017-08-01 We present results from high-resolution optical spectra toward 66 young stars in the Orion B molecular cloud to study their kinematics and other properties. Observations of the H α and Li i 6707 Å lines are used to check membership and accretion properties. While the stellar radial velocities of NGC 2068 and L1622 are in good agreement with that of the molecular gas, many of the stars in NGC 2024 show a considerable offset. This could be a signature of either the expansion of the cluster, the high degree of the ejection of the stars from the cluster through dynamical interaction, or the acceleration of the gas due to stellar feedback. 1. The kinematics of machinery outlines of a theory of machines CERN Document Server Reuleaux, Franz 2012-01-01 A classic on the kinematics of machinery, this volume was written by the Father of Kinematics. Reuleaux writes with authority and precision, developing the subject from its fundamentals. 450 figures. 1876 edition. 2. Lingual Kinematics during Rapid Syllable Repetition in Parkinson's Disease Science.gov (United States) Wong, Min Ney; Murdoch, Bruce E.; Whelan, Brooke-Mai 2012-01-01 Background: Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). Aims: To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric… 3. Kinematics and resolution at future ep colliders International Nuclear Information System (INIS) Bluemlein, J.; Klein, M. 1992-01-01 Limitations due to resolution and kinematics are discussed of the (Q 2 , x) range accessible with electron-proton colliders after HERA. For the time after HERA one may think of two electron-proton colliders: an asymmetric energy machine and a rather symmetric one. Both colliders are compared here in order to study the influence of the different E l /E p ratios on the accessible kinematic range which is restricted due to angular coverage, finite detector resolution and calibration uncertainties 4. Kinematics Analysis and Simulation on Transfer Robot with Six Degrees of Freedom Directory of Open Access Journals (Sweden) Yi Lu 2014-08-01 Full Text Available Study focuses on transfer robot with Six Degrees of Freedom, establishing kinematic equation by D-H method, analyzing forward kinematics and obtaining inverse kinematics by using method of inverse transform. Based on vector product, it develops velocity Jacobian matrix of robot. The geometric model of robot virtual prototype is established by SolidWorks software and generates parameters such as mass and moment. Kinematic simulation for robot is performed by Mathematica software and develops curve graph of displacement, velocity and accelerated speed in x, y and z direction in end executor center of robot with measurement, analysis and assessment, which provides foundation for further kinematics analysis and structure optimization as well as motion control of robot. 5. Software Development for the Kinematic Analysis of a Lynx 6 Robot Arm OpenAIRE Baki Koyuncu; Mehmet Güzel 2007-01-01 The kinematics of manipulators is a central problem in the automatic control of robot manipulators. Theoretical background for the analysis of the 5 Dof Lynx-6 educational Robot Arm kinematics is presented in this paper. The kinematics problem is defined as the transformation from the Cartesian space to the joint space and vice versa. The Denavit-Harbenterg (D-H) model of representation is used to model robot links and joints in this study. Both forward and inverse kinematics solutions for th... 6. Form of relativistic dynamics with world lines International Nuclear Information System (INIS) Mukunda, N.; Sudarshan, E.C.G. 1981-01-01 In any Hamiltonian relativistic theory there are ten generators of the Poincare group which are realized canonically. The dynamical evolution is described by a Hamiltonian which is one of the ten generators in Dirac's generator formalism. The requirement that the canonical transformations reproduce the geometrical transformation of world points generates the world-line conditions. The Dirac identification of the Hamiltonian and the world-line conditions together lead to the no-interaction theorem. Interacting relativistic theories with world-line conditions should go beyond the Dirac theory and have eleven generators. In this paper we present a constraint dynamics formalism which describes an eleven-generator theory of N interacting particles using 8(N+1) variables with suitable constraints. The (N+1)th pair of four-vectors is associated with the uniform motion of a center which coincides with the center of energy for free particles. In such theories dynamics and kinematics cannot be separated out in a simple fashion 7. Augmented kinematic feedback from haptic virtual reality for dental skill acquisition. Science.gov (United States) Suebnukarn, Siriwan; Haddawy, Peter; Rhienmora, Phattanapon; Jittimanee, Pannapa; Viratket, Piyanuch 2010-12-01 We have developed a haptic virtual reality system for dental skill training. In this study we examined several kinds of kinematic information about the movement provided by the system supplement knowledge of results (KR) in dental skill acquisition. The kinematic variables examined involved force utilization (F) and mirror view (M). This created three experimental conditions that received augmented kinematic feedback (F, M, FM) and one control condition that did not (KR-only). Thirty-two dental students were randomly assigned to four groups. Their task was to perform access opening on the upper first molar with the haptic virtual reality system. An acquisition session consisted of two days of ten trials of practice in which augmented kinematic feedback was provided for the appropriate experimental conditions after each trial. One week after, a retention test consisting of two trials without augmented feedback was completed. The results showed that the augmented kinematic feedback groups had larger mean performance scores than the KR-only group in Day 1 of the acquisition and retention sessions (ANOVA, p0.05). The trends in acquisition and retention sessions suggest that the augmented kinematic feedback can enhance the performance earlier in the skill acquisition and retention sessions. 8. Sex Differences in Tibiocalcaneal Kinematics Directory of Open Access Journals (Sweden) Sinclair Jonathan 2014-08-01 Full Text Available Purpose. Female runners typically suffer more from chronic running injuries than age-matched males, although the exact biome-chanical mechanisms behind the increased susceptibility of female runners are unknown. This study aimed to compare sex differences in tibiocalcaneal kinematics during the stance phase of running. Methods. Twenty male and twenty female participants ran at 4.0 m · s–1. Tibiocalcaneal kinematics were measured using an eight-camera motion analysis system and compared using independent samples t tests. Results. Peak eversion and tibial internal rotation angles were shown to be significantly greater in female runners. Conclusions. based on these observations, it was determined that female runners may be at increased risk from chronic injury development in relation to excessive tibiocalcaneal motions in the coronal and transverse planes. 9. NEW STRONG-LINE ABUNDANCE DIAGNOSTICS FOR H II REGIONS: EFFECTS OF κ-DISTRIBUTED ELECTRON ENERGIES AND NEW ATOMIC DATA Energy Technology Data Exchange (ETDEWEB) Dopita, Michael A.; Sutherland, Ralph S.; Nicholls, David C.; Kewley, Lisa J.; Vogt, Frédéric P. A., E-mail: Michael.Dopita@anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University, Cotter Rd., Weston ACT 2611 (Australia) 2013-09-01 Recently, Nicholls et al., inspired by in situ observations of solar system astrophysical plasmas, suggested that the electrons in H II regions are characterized by a κ-distribution of energies rather than a simple Maxwell-Boltzmann distribution. Here, we have collected together new atomic data within a modified photoionization code to explore the effects of both the new atomic data and the κ-distribution on the strong-line techniques used to determine chemical abundances in H II regions. By comparing the recombination temperatures (T {sub rec}) with the forbidden line temperatures (T {sub FL}), we conclude that κ ∼ 20. While representing only a mild deviation from equilibrium, this result is sufficient to strongly influence abundances determined using methods that depend on measurements of the electron temperature from forbidden lines. We present a number of new emission line ratio diagnostics that cleanly separate the two parameters determining the optical spectrum of H II regions—the ionization parameter q or U and the chemical abundance, 12+log(O/H). An automated code to extract these parameters is presented. Using the homogeneous data set from van Zee et al., we find self-consistent results between all of these different diagnostics. The systematic errors between different line ratio diagnostics are much smaller than those found in the earlier strong-line work. Overall, the effect of the κ-distribution on the strong-line abundances derived solely on the basis of theoretical models is rather small. 10. Examining Acoustic and Kinematic Measures of Articulatory Working Space: Effects of Speech Intensity. Science.gov (United States) Whitfield, Jason A; Dromey, Christopher; Palmer, Panika 2018-04-18 The purpose of this study was to examine the effect of speech intensity on acoustic and kinematic vowel space measures and conduct a preliminary examination of the relationship between kinematic and acoustic vowel space metrics calculated from continuously sampled lingual marker and formant traces. Young adult speakers produced 3 repetitions of 2 different sentences at 3 different loudness levels. Lingual kinematic and acoustic signals were collected and analyzed. Acoustic and kinematic variants of several vowel space metrics were calculated from the formant frequencies and the position of 2 lingual markers. Traditional metrics included triangular vowel space area and the vowel articulation index. Acoustic and kinematic variants of sentence-level metrics based on the articulatory-acoustic vowel space and the vowel space hull area were also calculated. Both acoustic and kinematic variants of the sentence-level metrics significantly increased with an increase in loudness, whereas no statistically significant differences in traditional vowel-point metrics were observed for either the kinematic or acoustic variants across the 3 loudness conditions. In addition, moderate-to-strong relationships between the acoustic and kinematic variants of the sentence-level vowel space metrics were observed for the majority of participants. These data suggest that both kinematic and acoustic vowel space metrics that reflect the dynamic contributions of both consonant and vowel segments are sensitive to within-speaker changes in articulation associated with manipulations of speech intensity. 11. Broad line regions in Seyfert-1 galaxies International Nuclear Information System (INIS) Groningen, E. van. 1984-01-01 To reproduce observed emission profiles of Seyfert galaxies, rotation in an accretion disk has been proposed. In this thesis, the profiles emitted by such an accretion disk are investigated. Detailed comparison with the observed profiles yields that a considerable fraction can be fitted with a power-law function, as predicted by the model. The author analyzes a series of high quality spectra of Seyfert galaxies, obtained with the 2.5m telescope at Las Campanas. He presents detailed analyses of two objects: Mkn335 and Akn120. In both cases, strong evidence is presented for the presence of two separate broad line zones. These zones are identified with an accretion disk and an outflowing wind. The disk contains gas with very high densities and emits predominantly the lower ionization lines. He reports on the discovery of very broad wings beneath the strong forbidden line 5007. (Auth.) 12. Long-term Variability of H2CO Masers in Star-forming Regions Science.gov (United States) Andreev, N.; Araya, E. D.; Hoffman, I. M.; Hofner, P.; Kurtz, S.; Linz, H.; Olmi, L.; Lorran-Costa, I. 2017-10-01 We present results of a multi-epoch monitoring program on variability of 6 cm formaldehyde (H2CO) masers in the massive star-forming region NGC 7538 IRS 1 from 2008 to 2015, conducted with the Green Bank Telescope, the Westerbork Radio Telescope , and the Very Large Array. We found that the similar variability behaviors of the two formaldehyde maser velocity components in NGC 7538 IRS 1 (which was pointed out by Araya and collaborators in 2007) have continued. The possibility that the variability is caused by changes in the maser amplification path in regions with similar morphology and kinematics is discussed. We also observed 12.2 GHz methanol and 22.2 GHz water masers toward NGC 7538 IRS 1. The brightest maser components of CH3OH and H2O species show a decrease in flux density as a function of time. The brightest H2CO maser component also shows a decrease in flux density and has a similar LSR velocity to the brightest H2O and 12.2 GHz CH3OH masers. The line parameters of radio recombination lines and the 20.17 and 20.97 GHz CH3OH transitions in NGC 7538 IRS 1 are also reported. In addition, we observed five other 6 cm formaldehyde maser regions. We found no evidence of significant variability of the 6 cm masers in these regions with respect to previous observations, the only possible exception being the maser in G29.96-0.02. All six sources were also observed in the {{{H}}}213{CO} isotopologue transition of the 6 cm H2CO line; {{{H}}}213{CO} absorption was detected in five of the sources. Estimated column density ratios [{{{H}}}212{CO}]/[{{{H}}}213{CO}] are reported. 13. Accurate kinematic measurement at interfaces between dissimilar materials using conforming finite-element-based digital image correlation KAUST Repository Tao, Ran 2016-02-11 Digital image correlation (DIC) is now an extensively applied full-field measurement technique with subpixel accuracy. A systematic drawback of this technique, however, is the smoothening of the kinematic field (e.g., displacement and strains) across interfaces between dissimilar materials, where the deformation gradient is known to be large. This can become an issue when a high level of accuracy is needed, for example, in the interfacial region of composites or joints. In this work, we described the application of global conforming finite-element-based DIC technique to obtain precise kinematic fields at interfaces between dissimilar materials. Speckle images from both numerical and actual experiments processed by the described global DIC technique better captured sharp strain gradient at the interface than local subset-based DIC. © 2016 Elsevier Ltd. All rights reserved. 14. Human Gait Feature Extraction Including a Kinematic Analysis toward Robotic Power Assistance Directory of Open Access Journals (Sweden) Mario I. Chacon-Murguia 2012-09-01 Full Text Available The present work proposes a method for human gait and kinematic analysis. Gait analysis consists of the determination of hip, knee and ankle positions through video analysis. Gait kinematic for the thigh and knee is then generated from this data. Evaluations of the gait analysis method indicate an acceptable performance of 86.66% for hip and knee position estimation, and comparable findings with other reported works for gait kinematic. A coordinate systems assignment is performed according to the DH algorithm and a direct kinematic model of the legs is obtained. The legs' angles obtained from the video analysis are applied to the kinematic model in order to revise the application of this model to robotic legs in a power assisted system. 15. Stress Analysis of Boom of Special Mobile Crane for Plain Region in Transmission Line Science.gov (United States) Qin, Jian; Shao, Tao; Chen, Jun; Wan, Jiancheng; Li, Zhonghuan; Jiang, Ming 2017-10-01 Basis of the boom force analysis of special mobile crane for plain region in transmission line, the load type of boom design is confirmed. According to the different combinations of boom sections, the composite pattern of the different boom length is obtained to suit the actual conditions of boom overlapping. The large deformation model is employed with FEM to simulate the stress distribution of boom, and the calculation results are checked. The performance curves of rated load with different arm length and different working range are obtained, which ensures the lifting capacity of special mobile crane meeting the requirement of tower erection of transmission line. The proposed FEM of boom of mobile crane would provide certain guiding and reference to the boom design. 16. MODELING OF KINEMATICS OF A PLASTIC SHAPING AT CALIBRATION OF A THIN-WALLED PRECISION PIPE SINKING Directory of Open Access Journals (Sweden) E. D. Chertov 2014-01-01 Full Text Available Summary. The mathematical model of kinematics of a plastic shaping at the sinking of a thin-walled precision pipe applied to calibration of the ends of the unified elements of the pipeline of aircraft from titanic alloys and corrosion-resistant steel before assembly to the route by means of automatic argon-arc welding of ring joints is developed. For modeling, the power criterion of stability with use of kinematic possible fields of speeds is applied to receiving the top assessment of effort of deformation. The developed model of kinematics of a plastic current allows to receive power parameters of the main condition of process of calibration by sinking and can be used for the solution of a task on stability of process of deformation by results of comparison of power (power parameters for the main (steady and indignant states. Modeling is made in cylindrical system of coordinates by comparison of options of kinematic possible fields of the speeds of a current meeting a condition of incompressibility and kinematic regional conditions. The result of the modeling was selected discontinuous field of high-speed, in which the decrease outer radius (R occurs only by increasing the thickness of the pipe wall (t. For this option the size of pressure of sinking had the smallest value, therefore the chosen field of speeds closely to the valid. It is established that with increase in a step of giving 1 at calibration by the multisector tool the demanded pressure of sinking of q decreases. At an identical step of giving 1 pipe with the smaller relative thickness of (t/r needs to be calibrated the smaller pressure of sinking. With increase of a limit of fluidity at shift of material of pipe preparation pressure of sinking of (q increases. 17. Distances, Kinematics, And Structure Of The Orion Complex Science.gov (United States) Kounkel, Marina; Hartmann, Lee 2018-01-01 I present an analysis of the structure and kinematics of the Orion Molecular Cloud Complex in an effort to better characterize the dynamical state of the closest region of ongoing massive star formation. I measured stellar parallax and proper motions with Orion Complex. This includes the first direct distance measurements for sources that are located outside of the Orion Nebula. I identified a number of binary systems in the VLBI dataset and fitted their orbital motion, which allows for the direct measurement of the masses of the individual components. Additionally, I have identified several stars that have been ejected from the Orion Nebula due to strong gravitational interactions with the most massive members. I complemented the parallax and proper motion measurements with the observations of optical radial velocities of the stars toward the Orion Complex, probing the histories of both dynamic evolution and star formation in the region, providing a 6-dimensional model of the Complex. These observations can serve as a baseline for comparison of the upcoming results from the Gaia space telescope 18. Impact of uncertain reference-frame motions in plate kinematic reconstructions DEFF Research Database (Denmark) Iaffaldano, Giampiero; Stein, Seth 2017-01-01 Geoscientists infer past plate motions, which serve as fundamental constraints for a range of studies, from observations of magnetic isochrons as well as hotspots tracks on the ocean floor and, for stages older than the Cretaceous, from paleomagnetic data. These observations effectively represent...... time-integrals of past plate motions but, because they are made at present, yield plate kinematics naturally tied to a present-day reference-frame, which may be another plate or a hotspots system. These kinematics are therefore different than those occurred at the time when the rocks acquired...... – in a temporal sense – and prone to noise. This limitation is commonly perceived to hamper the correction of plate kinematic reconstructions for RFAMs, but the extent to which this may be the case has not been explored. Here we assess the impact of uncertain RFAMs on kinematic reconstructions using synthetic... 19. A kinematic approach for efficient and robust simulation of the cardiac beating motion. Directory of Open Access Journals (Sweden) Takashi Ijiri Full Text Available Computer simulation techniques for cardiac beating motions potentially have many applications and a broad audience. However, most existing methods require enormous computational costs and often show unstable behavior for extreme parameter sets, which interrupts smooth simulation study and make it difficult to apply them to interactive applications. To address this issue, we present an efficient and robust framework for simulating the cardiac beating motion. The global cardiac motion is generated by the accumulation of local myocardial fiber contractions. We compute such local-to-global deformations using a kinematic approach; we divide a heart mesh model into overlapping local regions, contract them independently according to fiber orientation, and compute a global shape that satisfies contracted shapes of all local regions as much as possible. A comparison between our method and a physics-based method showed that our method can generate motion very close to that of a physics-based simulation. Our kinematic method has high controllability; the simulated ventricle-wall-contraction speed can be easily adjusted to that of a real heart by controlling local contraction timing. We demonstrate that our method achieves a highly realistic beating motion of a whole heart in real time on a consumer-level computer. Our method provides an important step to bridge a gap between cardiac simulations and interactive applications. 20. Scattering forms and the positive geometry of kinematics, color and the worldsheet Science.gov (United States) Arkani-Hamed, Nima; Bai, Yuntao; He, Song; Yan, Gongwang 2018-05-01 The search for a theory of the S-Matrix over the past five decades has revealed surprising geometric structures underlying scattering amplitudes ranging from the string worldsheet to the amplituhedron, but these are all geometries in auxiliary spaces as opposed to the kinematical space where amplitudes actually live. Motivated by recent advances providing a reformulation of the amplituhedron and planar N = 4 SYM amplitudes directly in kinematic space, we propose a novel geometric understanding of amplitudes in more general theories. The key idea is to think of amplitudes not as functions, but rather as differential forms on kinematic space. We explore the resulting picture for a wide range of massless theories in general spacetime dimensions. For the bi-adjoint ϕ 3 scalar theory, we establish a direct connection between its "scattering form" and a classic polytope — the associahedron — known to mathematicians since the 1960's. We find an associahedron living naturally in kinematic space, and the tree level amplitude is simply the "canonical form" associated with this "positive geometry". Fundamental physical properties such as locality and unitarity, as well as novel "soft" limits, are fully determined by the combinatorial geometry of this polytope. Furthermore, the moduli space for the open string worldsheet has also long been recognized as an associahedron. We show that the scattering equations act as a diffeomorphism between the interior of this old "worldsheet associahedron" and the new "kinematic associahedron", providing a geometric interpretation and simple conceptual derivation of the bi-adjoint CHY formula. We also find "scattering forms" on kinematic space for Yang-Mills theory and the Non-linear Sigma Model, which are dual to the fully color-dressed amplitudes despite having no explicit color factors. This is possible due to a remarkable fact—"Color is Kinematics"— whereby kinematic wedge products in the scattering forms satisfy the same Jacobi 1. Interactive inverse kinematics for human motion estimation DEFF Research Database (Denmark) Engell-Nørregård, Morten Pol; Hauberg, Søren; Lapuyade, Jerome 2009-01-01 We present an application of a fast interactive inverse kinematics method as a dimensionality reduction for monocular human motion estimation. The inverse kinematics solver deals efficiently and robustly with box constraints and does not suffer from shaking artifacts. The presented motion...... to significantly speed up the particle filtering. It should be stressed that the observation part of the system has not been our focus, and as such is described only from a sense of completeness. With our approach it is possible to construct a robust and computationally efficient system for human motion estimation.... 2. An engineering geological appraisal of the Chamshir dam foundation using DMR classification and kinematic analysis, southwest of Iran Directory of Open Access Journals (Sweden) Torabi Kaveh Mehdi 2011-12-01 Full Text Available This paper describes the results of engineering geological investigations and rock mechanics studies carried out at the proposed Chamshir dam site. It is proposed that a 155 m high solid concrete gravity-arc dam be built across the Zuhreh River to the southeast of the city of Gachsaran in south-western Iran. The dam and its associated structures are mainly located on the Mishan formation. Analysis consisted of rock mass classification and a kinematic analysis of the dam foundation's rock masses. The studies were carried out in the field and the laboratory. The field studies included geological mapping, intensive discontinuity surveying, core drilling and sampling for laboratory testing. Rock mass classifications were made in line with RMR and DMR classification for the dam foundation. Dam foundation analysis regarding stability using DMR classification and kinematic analysis indicated that the left abutment's rock foundation (area 2 was unstable for planar, wedge and toppling failure modes. 3. A Deep Chandra ACIS Study of NGC 4151. II. The Innermost Emission Line Region and Strong Evidence for Radio Jet-NLR Cloud Collision Science.gov (United States) Wang, Junfeng; Fabbiano, Giuseppina; Elvis, Martin; Risaliti, Guido; Mundell, Carole G.; Karovska, Margarita; Zezas, Andreas 2011-07-01 We have studied the X-ray emission within the inner ~150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of blended O VII, O VIII, and Ne IX. These maps show extended structures that are spatially correlated with the radio outflow and optical [O III] emission. We find strong evidence for jet-gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [Fe II] emission, and optical clouds. In these regions, moreover, we find evidence of elevated Ne IX/O VII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that >~ 0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circumnuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe Kα emission is <~ 5% of the total, in disagreement with a previous claim that 65% of the Fe Kα emission originates in the extended narrow line region. 4. On the origin of gamma rays in Fermi blazars: beyond the broad line region. Science.gov (United States) Costamante, L.; Cutini, S.; Tosti, G.; Antolini, E.; Tramacere, A. 2018-05-01 The gamma-ray emission in broad-line blazars is generally explained as inverse Compton (IC) radiation of relativistic electrons in the jet scattering optical-UV photons from the Broad Line Region (BLR), the so-called BLR External Compton scenario. We test this scenario on the Fermi gamma-ray spectra of 106 broad-line blazars detected with the highest significance or largest BLR, by looking for cut-off signatures at high energies compatible with γ-γ interactions with BLR photons. We do not find evidence for the expected BLR absorption. For 2/3 of the sources, we can exclude any significant absorption (τmax 5). We conclude that for 9 out of 10 objects, the jet does not interact with BLR photons. Gamma-rays seem either produced outside the BLR most of the time, or the BLR is ˜100 × larger than given by reverberation mapping. This means that i) External Compton on BLR photons is disfavoured as the main gamma-ray mechanism, vs IC on IR photons from the torus or synchrotron self-Compton; ii) the Fermi gamma-ray spectrum is mostly intrinsic, determined by the interaction of the particle distribution with the seed-photons spectrum; iii) without suppression by the BLR, broad-line blazars can become copious emitters above 100 GeV, as demonstrated by 3C 454.3. We expect the CTA sky to be much richer of broad-line blazars than previously thought. 5. Kinematic and Dynamic Analysis of a Lower Limb Exoskeleton OpenAIRE Tawakal Hasnain Baluch; Adnan Masood; Javaid Iqbal; Umer Izhar; Umar Shahbaz Khan 2012-01-01 This paper will provide the kinematic and dynamic analysis of a lower limb exoskeleton. The forward and inverse kinematics of proposed exoskeleton is performed using Denevit and Hartenberg method. The torques required for the actuators will be calculated using Lagrangian formulation technique. This research can be used to design the control of the proposed exoskeleton. 6. Scapular kinematics during manual wheelchair propulsion in able-bodied participants NARCIS (Netherlands) Bekker, Michel J.; Vegter, Riemer J.K.; van der Scheer, Jan W.; Hartog, Johanneke; de Groot, Sonja; de Vries, Wiebe; Arnet, Ursina; van der Woude, Lucas H.V.; Veeger, Dirkjan (.H.E.J) Background: Altered scapular kinematics have been associated with shoulder pain and functional limitations. To understand kinematics in persons with spinal cord injury during manual handrim wheelchair propulsion, a description of normal scapular behaviour in able-bodied persons during this specific 7. Scapular kinematics during manual wheelchair propulsion in able-bodied participants NARCIS (Netherlands) Bekker, Michel J; Vegter, Riemer J K; van der Scheer, Jan W; Hartog, Johanneke; de Groot, Sonja; de Vries, Wiebe; Arnet, Ursina; van der Woude, Lucas H V; Veeger, Dirkjan H E J BACKGROUND: Altered scapular kinematics have been associated with shoulder pain and functional limitations. To understand kinematics in persons with spinal cord injury during manual handrim wheelchair propulsion, a description of normal scapular behaviour in able-bodied persons during this specific 8. Kinematic Fitting of Detached Vertices Energy Technology Data Exchange (ETDEWEB) Mattione, Paul [Rice Univ., Houston, TX (United States) 2007-05-01 The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the\\Xi_{5}$pentaquarks and investigate the excited$\\Xi$states. Specifically, the exotic$\\Xi_{5}^{--}$pentaquark will be sought by first reconstructing the$\\Xi^{-}$particle through its weak decays,$\\Xi^{-}\\to\\pi^{-}\\Lambda$and$\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction$\\gamma D\\rightarrow pp\\pi^{-}$was studied in order to correct the track measurements and covariance matrices of the charged particles. The$\\Lambda\\rightarrow p\\pi^{-}$and$\\Xi^{-}\\to\\pi^{-}\\Lambda\$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.
9. Sex Differences in Anthropometrics and Heading Kinematics Among Division I Soccer Athletes.
Science.gov (United States)
Bretzin, Abigail C; Mansell, Jamie L; Tierney, Ryan T; McDevitt, Jane K
Soccer players head the ball repetitively throughout their careers; this is also a potential mechanism for a concussion. Although not all soccer headers result in a concussion, these subconcussive impacts may impart acceleration, deceleration, and rotational forces on the brain, leaving structural and functional deficits. Stronger neck musculature may reduce head-neck segment kinematics. The relationship between anthropometrics and soccer heading kinematics will not differ between sexes. The relationship between anthropometrics and soccer heading kinematics will not differ between ball speeds. Pilot, cross-sectional design. Level 3. Division I soccer athletes (5 male, 8 female) were assessed for head-neck anthropometric and neck strength measurements in 6 directions (ie, flexion, extension, right and left lateral flexions and rotations). Participants headed the ball 10 times (25 or 40 mph) while wearing an accelerometer secured to their head. Kinematic measurements (ie, linear acceleration and rotational velocity) were recorded at 2 ball speeds. Sex differences were observed in neck girth ( t = 5.09, P soccer heading kinematics for sex and ball speeds. Neck girth and neck strength are factors that may limit head impact kinematics.
10. Kinematics of machinery through hyperworks
CERN Document Server
Rao, J S
2011-01-01
Using animations, this book explains the theory of machines concepts and the evolution of Kinematics. The book adopts HyperWorks MotionSolve to perform the analysis and visualizations, though the book is independent of the requirement of any software.
11. Kinematic measurements using an infrared sensor
International Nuclear Information System (INIS)
Marinho, F; Paulucci, L
2016-01-01
The use of an infrared sensor as a new alternative to measure position as a function of time in kinematic experiments was investigated using a microcontroller as the data acquisition and control device. These are versatile sensors that offer advantages over typical ultrasound devices. The setup described in this paper enables students to develop their own experiments, promoting opportunities for learning physical concepts such as the different types of forces that can act on a body (gravitational, elastic, drag, etc) and the resulting types of movements with good sensitivity within the 4–30 cm range. As a proof of concept we also present the application of a prototype designed to record the kinematics of mass-spring systems. (paper)
12. The kinematic advantage of electric cars
Science.gov (United States)
Meyn, Jan-Peter
2015-11-01
Acceleration of a common car with with a turbocharged diesel engine is compared to the same type with an electric motor in terms of kinematics. Starting from a state of rest, the electric car reaches a distant spot earlier than the diesel car, even though the latter has a better specification for engine power and average acceleration from 0 to 100 km h-1. A three phase model of acceleration as a function of time fits the data of the electric car accurately. The first phase is a quadratic growth of acceleration in time. It is shown that the tenfold higher coefficient for the first phase accounts for most of the kinematic advantage of the electric car.
13. An introduction to the mathematics of ocular kinematics
Directory of Open Access Journals (Sweden)
Graeme E MacKenzie
2006-12-01
Full Text Available The research surrounding ocular kinematics has widespread applications including the study of binocular vision, virtual reality and the detec-tion of ocular and neurologic pathologies. This field promises to have a significant impact on optometric diagnostic techniques. This paper in-troduces the terminology used in the description of eye rotations and explores a number of the mathematical approaches pertinent to the topic of ocular kinematics.
14. Joint kinematics estimation using a multi-body kinematics optimisation and an extended Kalman filter, and embedding a soft tissue artefact model.
Science.gov (United States)
Bonnet, Vincent; Richard, Vincent; Camomilla, Valentina; Venture, Gentiane; Cappozzo, Aurelio; Dumas, Raphaël
2017-09-06
To reduce the impact of the soft tissue artefact (STA) on the estimate of skeletal movement using stereophotogrammetric and skin-marker data, multi-body kinematics optimisation (MKO) and extended Kalman filters (EKF) have been proposed. This paper assessed the feasibility and efficiency of these methods when they embed a mathematical model of the STA and simultaneously estimate the ankle, knee and hip joint kinematics and the model parameters. A STA model was used that provides an estimate of the STA affecting the marker-cluster located on a body segment as a function of the kinematics of the adjacent joints. The MKO and the EKF were implemented with and without the STA model. To assess these methods, intra-cortical pin and skin markers located on the thigh, shank, and foot of three subjects and tracked during the stance phase of running were used. Embedding the STA model in MKO and EKF reduced the average RMS of marker tracking from 12.6 to 1.6mm and from 4.3 to 1.9mm, respectively, showing that a STA model trial-specific calibration is feasible. Nevertheless, with the STA model embedded in MKO, the RMS difference between the estimated and the reference joint kinematics determined from the pin markers slightly increased (from 2.0 to 2.1deg) On the contrary, when the STA model was embedded in the EKF, this RMS difference was slightly reduced (from 2.0 to 1.7deg) thus showing a better potentiality of this method to attenuate STA effects and improve the accuracy of joint kinematics estimate. Copyright © 2017 Elsevier Ltd. All rights reserved.
15. The cloud radiative feedback of a midlatitude squall line system and implication for climate study
International Nuclear Information System (INIS)
Chin, H.N.S.
1992-01-01
The main objectives of this study are (1) to study the impact of longwave and shortwave radiation on the thermodynamic and kinematic structure of a midlatitude squall line; and (2) to explore the influence of specifically including the ice phase in the cloud-radiation feedback mechanism for climate models
16. Effects of robotically modulating kinematic variability on motor skill learning and motivation.
Science.gov (United States)
Duarte, Jaime E; Reinkensmeyer, David J
2015-04-01
It is unclear how the variability of kinematic errors experienced during motor training affects skill retention and motivation. We used force fields produced by a haptic robot to modulate the kinematic errors of 30 healthy adults during a period of practice in a virtual simulation of golf putting. On day 1, participants became relatively skilled at putting to a near and far target by first practicing without force fields. On day 2, they warmed up at the task without force fields, then practiced with force fields that either reduced or augmented their kinematic errors and were finally assessed without the force fields active. On day 3, they returned for a long-term assessment, again without force fields. A control group practiced without force fields. We quantified motor skill as the variability in impact velocity at which participants putted the ball. We quantified motivation using a self-reported, standardized scale. Only individuals who were initially less skilled benefited from training; for these people, practicing with reduced kinematic variability improved skill more than practicing in the control condition. This reduced kinematic variability also improved self-reports of competence and satisfaction. Practice with increased kinematic variability worsened these self-reports as well as enjoyment. These negative motivational effects persisted on day 3 in a way that was uncorrelated with actual skill. In summary, robotically reducing kinematic errors in a golf putting training session improved putting skill more for less skilled putters. Robotically increasing kinematic errors had no performance effect, but decreased motivation in a persistent way. Copyright © 2015 the American Physiological Society.
17. A Smooth Tour Construction Approach for a Mobile Robot with Kinematic Constraints
Directory of Open Access Journals (Sweden)
Ahmet Yazici
2013-10-01
Full Text Available Mobile robots are increasingly used for service-like applications in which the service points are known and the mobile robot starts from a starting location, visits all the service points requested and returns to the starting location. The tour construction problem in these applications can be treated as a Travelling Salesman Problem (TSP. Classical tour construction algorithms that are proposed for the TSP find tours do not consider robot kinematic constraints. These tours may have sharp turns at some service points. When a mobile robot follows such a tour, it stops, turns and speeds up again. Therefore, the robots waste a considerable amount of power and time. In these cases, tour smoothing can be used to overcome this problem. However, smoothing an existing tour may result in unnecessarily long tours. In this study, a Smooth Tour Construction (STC approach is proposed for mobile robots with kinematic constraints. The STC approach considers tour construction and tour smoothing concurrently. The logic behind the tour construction part of the approach is based on the Savings Algorithm (SA. The tour smoothing is based on Dubins' arc-line approach. Experiments are conducted for P3-DX robots in a laboratory environment. Comparisons are also drawn with various tour smoothing algorithms in simulation environments to demonstrate the effectiveness of the proposed STC approach.
18. Derivation of three closed loop kinematic velocity models using normalized quaternion feedback for an autonomous redundant manipulator with application to inverse kinematics
Energy Technology Data Exchange (ETDEWEB)
Unseren, M.A.
1993-04-01
The report discusses the orientation tracking control problem for a kinematically redundant, autonomous manipulator moving in a three dimensional workspace. The orientation error is derived using the normalized quaternion error method of Ickes, the Luh, Walker, and Paul error method, and a method suggested here utilizing the Rodrigues parameters, all of which are expressed in terms of normalized quaternions. The analytical time derivatives of the orientation errors are determined. The latter, along with the translational velocity error, form a dosed loop kinematic velocity model of the manipulator using normalized quaternion and translational position feedback. An analysis of the singularities associated with expressing the models in a form suitable for solving the inverse kinematics problem is given. Two redundancy resolution algorithms originally developed using an open loop kinematic velocity model of the manipulator are extended to properly take into account the orientation tracking control problem. This report furnishes the necessary mathematical framework required prior to experimental implementation of the orientation tracking control schemes on the seven axis CESARm research manipulator or on the seven-axis Robotics Research K1207i dexterous manipulator, the latter of which is to be delivered to the Oak Ridge National Laboratory in 1993.
19. Derivation of three closed loop kinematic velocity models using normalized quaternion feedback for an autonomous redundant manipulator with application to inverse kinematics
International Nuclear Information System (INIS)
Unseren, M.A.
1993-04-01
The report discusses the orientation tracking control problem for a kinematically redundant, autonomous manipulator moving in a three dimensional workspace. The orientation error is derived using the normalized quaternion error method of Ickes, the Luh, Walker, and Paul error method, and a method suggested here utilizing the Rodrigues parameters, all of which are expressed in terms of normalized quaternions. The analytical time derivatives of the orientation errors are determined. The latter, along with the translational velocity error, form a dosed loop kinematic velocity model of the manipulator using normalized quaternion and translational position feedback. An analysis of the singularities associated with expressing the models in a form suitable for solving the inverse kinematics problem is given. Two redundancy resolution algorithms originally developed using an open loop kinematic velocity model of the manipulator are extended to properly take into account the orientation tracking control problem. This report furnishes the necessary mathematical framework required prior to experimental implementation of the orientation tracking control schemes on the seven axis CESARm research manipulator or on the seven-axis Robotics Research K1207i dexterous manipulator, the latter of which is to be delivered to the Oak Ridge National Laboratory in 1993
20. Elementary introduction to relativistic kinematics
International Nuclear Information System (INIS)
Gerber, H.J.
1979-01-01
This paper includes the most important results and applications of the theory of special relativity to high energy phenomena; it provides an analysis of the kinematics of particle decays and reactions as well as an introduction to the Lorentz group
1. Flaring radio lanterns along the ridge line: long-term oscillatory motion in the jet of S5 1803+784
Science.gov (United States)
Kun, E.; Karouzos, M.; Gabányi, K. É.; Britzen, S.; Kurtanidze, O. M.; Gergely, L. Á.
2018-04-01
We present a detailed analysis of 30 very long baseline interferometric observations of the BL Lac object S5 1803+784 (z = 0.679), obtained between mean observational time 1994.67 and 2012.91 at observational frequency 15 GHz. The long-term behaviour of the jet ridge line reveals the jet experiences an oscillatory motion superposed on its helical jet kinematics on a time-scale of about 6 years. The excess variance of the positional variability indicates the jet components being farther from the VLBI core have larger amplitude in their position variations. The fractional variability amplitude shows slight changes in 3-year bins of the component's position. The temporal variability in the Doppler boosting of the ridge line results in jet regions behaving as flaring "radio lanterns". We offer a qualitative scenario leading to the oscillation of the jet ridge line, that utilizes the orbital motion of the jet emitter black hole due to a binary black hole companion. A correlation analysis implies composite origin of the flux variability of the jet components, emerging due to possibly both the evolving jet-structure and its intrinsic variability.
2. The Size-Luminosity Relationship of Quasar Narrow-Line Regions
Science.gov (United States)
Dempsey, Ross; Zakamska, Nadia L.
2018-04-01
The presence of an active galactic nucleus (AGN) can strongly affect its host. Due to the copious radiative power of the nucleus, the effects of radiative feedback can be detected over the entire host galaxy and sometimes well into the intergalactic space. In this paper we model the observed size-luminosity relationship of the narrow-line regions (NLRs) of AGN. We model the NLR as a collection of clouds in pressure equilibrium with the ionizing radiation, with each cloud producing line emission calculated by Cloudy. The sizes of the NLRs of powerful quasars are reproduced without any free parameters, as long as they contain massive (105M⊙ to 107M⊙) ionization-bounded clouds. At lower AGN luminosities the observed sizes are larger than the model sizes, likely due to additional unmodeled sources of ionization (e.g., star formation). We find that the observed saturation of sizes at ˜10kpc which is observed at high AGN luminosities (Lion ≃ 1046erg/s) is naturally explained by optically thick clouds absorbing the ionizing radiation and preventing illumination beyond a critical distance. Using our models in combination with observations of the [O III]/IR ratio and the [O III] size - IR luminosity relationship, we calculate the covering factor of the obscuring torus (and therefore the type 2 fraction within the quasar population) to be f = 0.5, though this is likely an upper bound. Finally, because the gas behind the ionization front is invisible in ionized gas transitions, emission-based NLR mass calculations underestimate the mass of the NLR and therefore of the energetics of ionized-gas winds.
3. 2D CFD description of the kinematic effects of movable inlet and outlet die wall transport motion and punch shape geometry on the dynamics of viscous flow during ECAE through Segal 2θ-dies for a range of channel angles
Directory of Open Access Journals (Sweden)
Alexander V. Perig
2017-11-01
Full Text Available Minimization of the dead zone (DZA in the process of material forming is a materials science problem. Geometric and kinematic approaches to the minimization of the DZA during Equal Channel Angular Extrusion (ECAE have been proposed, developed, analyzed, and documented. The present article is focused on a 2D Computational Fluid Dynamics (CFD description of the kinematic effects of punch shape geometry and inlet (IDW and outlet (ODW die wall motion on the DZA during ECAE of Viscous Incompressible Continuum (VIC through a Segal 2θ-die for a range of channel angles 60° ≤ 2θ ≤ 135°. Due attention has been given to the independent alternating transport motions of the IDW and ODW. Punch shape geometry and the kinematic modes of IDW and ODW motions for DZA minimization have been determined with a numerical solution of the boundary value problem for the Navier-Stokes equations in curl transfer form for VIC. Experimental verification was accomplished with an introduction of initial circular gridlines-based physical simulation techniques. For the first time, experimental verification of CFD-derived results was made through an additional superposition of empirically-derived digital photos with deformed elliptical gridlines in the channel intersection deformation zones and correspondent 2D numerical plots with CFD-derived flow lines and full flow velocities. An empirical DZA localization was experimentally determined as the location of minimally-deformed near circular markers. The computational DZA localization was numerically determined as a flow-lines-free zone (the first hypothesis or as a zone with near-zero values of full flow velocities (the second hypothesis. The relative DZA was estimated as a ratio of the measured DZA with respect to the area of the deformation zone in the channel intersection region. A good agreement was obtained between DZA values obtained with the first hypothesis and experimental results.
4. STRUCTURAL IDENTIFICATION OF DISTINCT INVERSIONS OF PLANAR KINEMATIC CHAINS
Directory of Open Access Journals (Sweden)
Dr. Shubhashis Sanyal
2011-12-01
Full Text Available 0 0 1 171 979 International Islamic University 8 2 1148 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman";} Inversions are various structural possibilities of a kinematic chain. The number of inversions depends on the number of links of a kinematic chain. At the stage of structural synthesis, identification of distinct structural inversions of a particular type of kinematic chain is necessary. Various researchers have proposed methods for identification of distinct inversions. Present method based on Link joint connectivity is proposed to identify the distinct inversions of a planar kinematic chain. Method is tested successfully on single degree and multiple degree of freedom planar kinematic chains. ABSTRAK: Penyonsangan merupakan kebarangkalian pelbagai struktur suatu rangkaian kinematik. Jumlah songsangan bergantung kepada jumlah hubungan suatu rangkaian kinematik. Pada peringkat sintesis struktur, pengenalan songsangan struktur yang berbeza untuk suatu jenis rangkaian kinematik adalah perlu. Ramai penyelidik telah mencadangkan pelbagai kaedah pengenalan songsangan yang berbeza. Kaedah terkini berdasarkan hubungan kesambungan bersama telah dicadangkan untuk mengenalpasti songsangan yang berbeza dalam suatu satah rangkaian kinematik.
5. High-resolution Laboratory Measurements of Coronal Lines near the Fe IX Line at 171 Å
Science.gov (United States)
Beiersdorfer, Peter; Träbert, Elmar
2018-02-01
We present high-resolution laboratory measurements in the spectral region between 165 and 175 Å that focus on the emission from various ions of C, O, F, Ne, S, Ar, Fe, and Ni. This wavelength region is centered on the λ171 Fe IX channel of the Atmospheric Imaging Assembly on the Solar Dynamics Observatory, and we place special emphasis on the weaker emission lines of Fe IX predicted in this region. In general, our measurements show a multitude of weak lines missing in the current databases, where the emission lines of Ni are probably most in need of further identification and reclassification. We also find that the wavelengths of some of the known lines need updating. Using the multi-reference Møller–Plesset method for wavelength predictions and collisional-radiative modeling of the line intensities, we have made tentative assignments of more than a dozen lines to the spectrum of Fe IX, some of which have formerly been identified as Fe VII, Fe XIV, or Fe XVI lines. Several Fe features remain unassigned, although they appear to be either Fe VII or Fe X lines. Further work will be needed to complete and correct the spectral line lists in this wavelength region.
6. General analytical shakedown solution for structures with kinematic hardening materials
Science.gov (United States)
Guo, Baofeng; Zou, Zongyuan; Jin, Miao
2016-09-01
The effect of kinematic hardening behavior on the shakedown behaviors of structure has been investigated by performing shakedown analysis for some specific problems. The results obtained only show that the shakedown limit loads of structures with kinematic hardening model are larger than or equal to those with perfectly plastic model of the same initial yield stress. To further investigate the rules governing the different shakedown behaviors of kinematic hardening structures, the extended shakedown theorem for limited kinematic hardening is applied, the shakedown condition is then proposed, and a general analytical solution for the structural shakedown limit load is thus derived. The analytical shakedown limit loads for fully reversed cyclic loading and non-fully reversed cyclic loading are then given based on the general solution. The resulting analytical solution is applied to some specific problems: a hollow specimen subjected to tension and torsion, a flanged pipe subjected to pressure and axial force and a square plate with small central hole subjected to biaxial tension. The results obtained are compared with those in literatures, they are consistent with each other. Based on the resulting general analytical solution, rules governing the general effects of kinematic hardening behavior on the shakedown behavior of structure are clearly.
7. Kinematic power corrections in off-forward hard reactions.
Science.gov (United States)
Braun, V M; Manashov, A N
2011-11-11
We develop a general approach to the calculation of kinematic corrections ∝t/Q(2), m(2)/Q(2) in hard processes which involve momentum transfer from the initial to the final hadron state. As the principal result, the complete expression is derived for the time-ordered product of two electromagnetic currents that includes all kinematic corrections to twist-four accuracy. The results are immediately applicable, e.g., to the studies of deeply virtual Compton scattering.
8. Footpoints of the giant molecular loops in the Galactic center region
Science.gov (United States)
Riquelme, D.; Amo-Baladrón, M. A.; Martín-Pintado, J.; Mauersberger, R.; Martín, S.; Burton, M.; Cunningham, M.; Jones, P. A.; Menten, K. M.; Bronfman, L.; Güsten, R.
2018-05-01
Aims: We aim to reveal the morphology, chemical composition, kinematics, and to establish the main processes prevalent in the gas at the footpoints of the giant molecular loops (GMLs) in the Galactic center region. Methods: Using the 22-m Mopra telescope, we mapped the M-3.8+0.9 molecular cloud, placed at the footpoints of a GML, in 3-mm range molecular lines. To derive the molecular hydrogen column density, we also observed the 13CO(2 - 1) line at 1 mm using the 12-m APEX telescope. From the 3 mm observations 12 molecular species were detected, namely HCO+, HCN, H13CN, HNC, SiO, CS, CH3OH, N2H+, SO, HNCO, OCS, and HC3N. Results: Maps revealing the morphology and kinematics of the M-3.8+0.9 molecular cloud in different molecules are presented. We identify six main molecular complexes. We derive fractional abundances in 11 selected positions of the different molecules assuming local thermodynamical equilibrium. Conclusions: Most of the fractional abundances derived for the M-3.8+0.9 molecular cloud are very similar over the whole cloud. However, the fractional abundances of some molecules show significant difference with respect to those measured in the central molecular zone (CMZ). The abundances of the shock tracer SiO are very similar between the GMLs and the CMZ. The methanol emission is the most abundant species in the GMLs. This indicates that the gas is likely affected by moderate 30 km s-1 or even high velocity (50 km s-1) shocks, consistent with the line profile observed toward one of the studied position. The origin of the shocks is likely related to the flow of the gas throughout the GMLs towards the footpoints. OPRA and APEX final data cubes (FITS) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/613/A42
9. Surgical gesture classification from video and kinematic data.
Science.gov (United States)
Zappella, Luca; Béjar, Benjamín; Hager, Gregory; Vidal, René
2013-10-01
Much of the existing work on automatic classification of gestures and skill in robotic surgery is based on dynamic cues (e.g., time to completion, speed, forces, torque) or kinematic data (e.g., robot trajectories and velocities). While videos could be equally or more discriminative (e.g., videos contain semantic information not present in kinematic data), they are typically not used because of the difficulties associated with automatic video interpretation. In this paper, we propose several methods for automatic surgical gesture classification from video data. We assume that the video of a surgical task (e.g., suturing) has been segmented into video clips corresponding to a single gesture (e.g., grabbing the needle, passing the needle) and propose three methods to classify the gesture of each video clip. In the first one, we model each video clip as the output of a linear dynamical system (LDS) and use metrics in the space of LDSs to classify new video clips. In the second one, we use spatio-temporal features extracted from each video clip to learn a dictionary of spatio-temporal words, and use a bag-of-features (BoF) approach to classify new video clips. In the third one, we use multiple kernel learning (MKL) to combine the LDS and BoF approaches. Since the LDS approach is also applicable to kinematic data, we also use MKL to combine both types of data in order to exploit their complementarity. Our experiments on a typical surgical training setup show that methods based on video data perform equally well, if not better, than state-of-the-art approaches based on kinematic data. In turn, the combination of both kinematic and video data outperforms any other algorithm based on one type of data alone. Copyright © 2013 Elsevier B.V. All rights reserved.
10. Improved Inverse Kinematics Algorithm Using Screw Theory for a Six-DOF Robot Manipulator
OpenAIRE
Chen, Qingcheng; Zhu, Shiqiang; Zhang, Xuequn
2015-01-01
Based on screw theory, a novel improved inverse-kinematics approach for a type of six-DOF serial robot, “Qianjiang I”, is proposed in this paper. The common kinematics model of the robot is based on the Denavit-Hartenberg (D-H) notation method while its inverse kinematics has inefficient calculation and complicated solution, which cannot meet the demands of online real-time application. To solve this problem, this paper presents a new method to improve the efficiency of the inverse kinematics...
11. Kinematic synthesis of a new 3D printing solution
Directory of Open Access Journals (Sweden)
Giberti Hermes
2016-01-01
The object of this article is the kinematic synthesis of a 5Dofs robot, based on two PKM machines, for additive manufacturing in order to compliant with the requirements of this new technology. Robot kinematics have been optimized by genetic algorithm in order to cover the required workspace and the design of the robot and outline of the control system are also given.
12. Factors associated with cervical kinematic impairments in patients with neck pain.
Science.gov (United States)
Treleaven, Julia; Chen, Xiaoqi; Sarig Bahat, Hilla
2016-04-01
Cervical kinematics have functional relevance and are important for assessment and management in patients with neck disorders. A better understanding of factors that might influence cervical kinematics is required. The aim of this study was to determine any relationships between altered kinematics to the symptoms and signs of sensorimotor impairments, neck pain and disability and fear of neck motion in people with neck pain. Kinematics were measured in 39 subjects with chronic neck pain using a customized virtual reality system. Range of cervical motion, mean and peak velocity, time to peak velocity percentage, number of velocity peaks and accuracy were derived. Correlations between these measures to self-reported (neck pain intensity, disability, fear of motion, dizziness, visual disturbances) and sensorimotor measures and regression analyses were conducted. Range and velocity of motion of cervical rotation appeared to be most related to visual disturbances and pain or dynamic balance. Nevertheless these relationships only explained about 30% of the variance of each measure. Signs and symptoms of sensorimotor dysfunction should be considered and monitored in the management of altered cervical rotation kinematics in patients with chronic neck disorders. Future research should consider the effects of addressing these factors on neck kinematics and vice versa to aid functional recovery in those with neck pain. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.
13. SIMULTANEOUS ULTRAVIOLET AND OPTICAL EMISSION-LINE PROFILES OF QUASARS: IMPLICATIONS FOR BLACK HOLE MASS DETERMINATION
International Nuclear Information System (INIS)
Ho, Luis C.; Dong Xiaobo; Goldoni, Paolo; Ponti, Gabriele; Greene, Jenny E.
2012-01-01
The X-shooter instrument on the Very Large Telescope was used to obtain spectra of seven moderate-redshift quasars simultaneously covering the spectral range ∼3000 Å to 2.5 μm. At z ≈ 1.5, most of the prominent broad emission lines in the ultraviolet to optical region are captured in their rest frame. We use this unique data set, which mitigates complications from source variability, to intercompare the line profiles of C IV λ1549, C III] λ1909, Mg II λ2800, and Hα and evaluate their implications for black hole (BH) mass estimation. We confirm that Mg II and the Balmer lines share similar kinematics and that they deliver mutually consistent BH mass estimates with minimal internal scatter (∼<0.1 dex) using the latest virial mass estimators. Although no virial mass formalism has yet been calibrated for C III], this line does not appear promising for such an application because of the large spread of its velocity width compared to lines of both higher and lower ionization; part of the discrepancy may be due to the difficulty of deblending C III] from its neighboring lines. The situation for C IV is complex and, because of the limited statistics of our small sample, inconclusive. On the one hand, slightly more than half of our sample (4/7) have C IV line widths that correlate reasonably well with Hα line widths, and their respective BH mass estimates agree to within ∼0.15 dex. The rest, on the other hand, exhibit exceptionally broad C IV profiles that overestimate virial masses by factors of 2-5 compared to Hα. As C IV is widely used to study BH demographics at high redshifts, we urgently need to revisit our analysis with a larger sample.
14. A DEEP CHANDRA ACIS STUDY OF NGC 4151. II. THE INNERMOST EMISSION LINE REGION AND STRONG EVIDENCE FOR RADIO JET-NLR CLOUD COLLISION
International Nuclear Information System (INIS)
Wang Junfeng; Fabbiano, Giuseppina; Elvis, Martin; Risaliti, Guido; Karovska, Margarita; Zezas, Andreas; Mundell, Carole G.
2011-01-01
We have studied the X-ray emission within the inner ∼150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of blended O VII, O VIII, and Ne IX. These maps show extended structures that are spatially correlated with the radio outflow and optical [O III] emission. We find strong evidence for jet-gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [Fe II] emission, and optical clouds. In these regions, moreover, we find evidence of elevated Ne IX/O VII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that ∼> 0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circumnuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe Kα emission is ∼< 5% of the total, in disagreement with a previous claim that 65% of the Fe Kα emission originates in the extended narrow line region.
15. A multi-subject evaluation of uncertainty in anatomical landmark location on shoulder kinematic description.
Science.gov (United States)
Langenderfer, Joseph E; Rullkoetter, Paul J; Mell, Amy G; Laz, Peter J
2009-04-01
An accurate assessment of shoulder kinematics is useful for understanding healthy normal and pathological mechanics. Small variability in identifying and locating anatomical landmarks (ALs) has potential to affect reported shoulder kinematics. The objectives of this study were to quantify the effect of landmark location variability on scapular and humeral kinematic descriptions for multiple subjects using probabilistic analysis methods, and to evaluate the consistency in results across multiple subjects. Data from 11 healthy subjects performing humeral elevation in the scapular plane were used to calculate Euler angles describing humeral and scapular kinematics. Probabilistic analyses were performed for each subject to simulate uncertainty in the locations of 13 upper-extremity ALs. For standard deviations of 4 mm in landmark location, the analysis predicted Euler angle envelopes between the 1 and 99 percentile bounds of up to 16.6 degrees . While absolute kinematics varied with the subject, the average 1-99% kinematic ranges for the motion were consistent across subjects and sensitivity factors showed no statistically significant differences between subjects. The description of humeral kinematics was most sensitive to the location of landmarks on the thorax, while landmarks on the scapula had the greatest effect on the description of scapular elevation. The findings of this study can provide a better understanding of kinematic variability, which can aid in making accurate clinical diagnoses and refining kinematic measurement techniques.
16. Hallux valgus surgery affects kinematic parameters during gait.
Science.gov (United States)
Klugarova, Jitka; Janura, Miroslav; Svoboda, Zdenek; Sos, Zdenek; Stergiou, Nicholas; Klugar, Miloslav
2016-12-01
The aim of our study was to compare spatiotemporal parameters and lower limb and pelvis kinematics during the walking in patients with hallux valgus before and after surgery and in relation to a control group. Seventeen females with hallux valgus, who underwent first metatarsal osteotomy, constituted our experimental group. The control group consisted of thirteen females. Kinematic data during walking were obtained using the Vicon MX system. Our results showed that hallux valgus before surgery affects spatiotemporal parameters and lower limb and pelvis kinematics during walking. Hallux valgus surgery further increased the differences that were present before surgery. Specifically after hallux valgus surgery, the walking speed decreased even more (p=0.09, η 2 =0.19) while step time increased (p=0.002, η 2 =0.44) on both legs. The maximum ankle plantar flexion of the operated leg during toe-off decreased to a greater extend (p=0.03, η 2 =0.26). The asymmetry in the hip and the pelvis movements in the frontal plane (present preoperatively) persisted after surgery. Hallux valgus is not an isolated problem of the first ray, which could be just surgically addressed by correcting the foot's alignment. It is a long-term progressive malfunction of the foot affecting the entire kinematic chain of the lower extremity. Copyright © 2016 Elsevier Ltd. All rights reserved.
17. The affect of the use of graphical materials on teaching kinematics
International Nuclear Information System (INIS)
Yener, D.
2005-01-01
In this study, a review of literature about graphical materials and kinematics was done. Preparing traditional questions supported by graphical materials on kinematics that applied to 119 first year students at secondary education mathematics department, and physics, chemistry and biology departments at Selcuk University Educational Faculty. The effect of the usage of graphical materials on teaching kinematics were searched. The data obtained from traditional questions and graphical questions were evaluated by using SPSS (Statistical Social Science for Package Program). At the end of this evaluation, it is obvious that if kinematics are taught with graphical materials, students can learn the subject better, thus, they solve the questions easierly and more rapidly. As a result, the students were more successful to solve the questions with graphical materials than traditional questions
18. Transfer reactions in inverse kinematics at REX-ISOLDE
CERN Document Server
Tengborn, E
Research on the structure of exotic nuclei is one of the most intriguing topics in present day nuclear physics. With the use of facilities for isotope separation on-line, such as ISOLDE at CERN, short-lived isotopes can be studied experimentally. Since 2002, the REX-ISOLDE facility enables radioactive ions produced by ISOLDE to be post-accelerated, increasing the energy of the ions enough to do nuclear transfer reactions in inverse kinematics. In this thesis, transfer reactions are used to study the structure of neutron-rich lithium isotopes through a series of experiments at REX-ISOLDE. The first experiment used a 9Li beam at 2.36 MeV/u impinging on a deuterated polyethylene target to study 10Li, 9Li and 8Li. For the (d,p)-channel the resonance ground state and a first excited state are observed and the results agree with theoretical calculations. The elastic channel agrees with Optical Model, OM, calculations. For the (d,t)-channel the shape of the angular distribution agrees with Distorted Wave Born Approx...
19. Response (re-)programming in aging: a kinematic analysis.
Science.gov (United States)
Bellgrove, M A; Phillips, J G; Bradshaw, J L; Gallucci, R M
1998-05-01
Age-related motor slowing may reflect either motor programming deficits, poorer movement execution, or mere strategic preferences for online guidance of movement. We controlled such preferences, limiting the extent to which movements could be programmed. Twenty-four young and 24 older adults performed a line drawing task that allowed movements to be prepared in advance in one case (i.e., cue initially available indicating target location) and not in another (i.e., no cue initially available as to target location). Participants connected large or small targets illuminated by light-emitting diodes upon a graphics tablet that sampled pen tip position at 200 Hz. Older adults had a disproportionate difficulty initiating movement when prevented from programming in advance. Older adults produced slower, less efficient movements, particularly when prevented from programming under greater precision requirements. The slower movements of older adults do not simply reflect a preference for online control, as older adults have less efficient movements when forced to reprogram their movements. Age-related motor slowing kinematically resembles that seen in patients with cerebellar dysfunction.
20. Program realization of mathematical model of kinematic calculation of flat lever mechanisms
Directory of Open Access Journals (Sweden)
M. A. Vasechkin
2016-01-01
Full Text Available Calculation of kinematic mechanisms is very time-consuming work. Due to the content of a large number of similar operations can be automated using computers. Forthis purpose, it is necessary to implement a software implementation ofthe mathematical model of calculation of kinematic mechanisms of the second class. In the article on Turbo Pascal presents the text module to library procedures all kinematic studies of planar lever mechanisms of the second class. The determination of the kinematic characteristics of the mechanism and the construction of its provisions, plans, plans, speeds and accelerations carried out on the example of the six-link mechanism. The beginning of the motionless coordinate system coincides with the axis of rotation of the crank AB. It is assumed that the known length of all links, the positions of all additional points of links and the coordinates of all kinematic pairs rack mechanism, i.e. this stage of work to determine the kinematics of the mechanism must be preceded by a stage of synthesis of mechanism (determining missing dimensions of links. Denote the coordinates of point C and considering that the analogues of velocities and accelerations of this point is 0 (stationary point, appeal to the procedure that computes the kinematics group the Assyrians (GA third. Specify kinematic parameters of point D, taking the beginning of the guide slide E at point C, the angle, the analogue of the angular velocity and the analogue of the angular acceleration of the guide is zero, knowing the length of the connecting rod DE and the length of link 5, refer to the procedure for the GA of the second kind. The use of library routines module of the kinematic calculation, makes it relatively simple to organize a simulation of the mechanism motion, to calculate the projection analogues of velocities and accelerations of all links of the mechanism, to build plans of the velocities and accelerations at each position of the mechanism.
1. Inverse kinematics problem in robotics using neural networks
Science.gov (United States)
Choi, Benjamin B.; Lawrence, Charles
1992-01-01
In this paper, Multilayer Feedforward Networks are applied to the robot inverse kinematic problem. The networks are trained with endeffector position and joint angles. After training, performance is measured by having the network generate joint angles for arbitrary endeffector trajectories. A 3-degree-of-freedom (DOF) spatial manipulator is used for the study. It is found that neural networks provide a simple and effective way to both model the manipulator inverse kinematics and circumvent the problems associated with algorithmic solution methods.
2. Design of a Two-Step Calibration Method of Kinematic Parameters for Serial Robots
Science.gov (United States)
WANG, Wei; WANG, Lei; YUN, Chao
2017-03-01
Serial robots are used to handle workpieces with large dimensions, and calibrating kinematic parameters is one of the most efficient ways to upgrade their accuracy. Many models are set up to investigate how many kinematic parameters can be identified to meet the minimal principle, but the base frame and the kinematic parameter are indistinctly calibrated in a one-step way. A two-step method of calibrating kinematic parameters is proposed to improve the accuracy of the robot's base frame and kinematic parameters. The forward kinematics described with respect to the measuring coordinate frame are established based on the product-of-exponential (POE) formula. In the first step the robot's base coordinate frame is calibrated by the unit quaternion form. The errors of both the robot's reference configuration and the base coordinate frame's pose are equivalently transformed to the zero-position errors of the robot's joints. The simplified model of the robot's positioning error is established in second-power explicit expressions. Then the identification model is finished by the least square method, requiring measuring position coordinates only. The complete subtasks of calibrating the robot's 39 kinematic parameters are finished in the second step. It's proved by a group of calibration experiments that by the proposed two-step calibration method the average absolute accuracy of industrial robots is updated to 0.23 mm. This paper presents that the robot's base frame should be calibrated before its kinematic parameters in order to upgrade its absolute positioning accuracy.
3. A Projected Non-linear Conjugate Gradient Method for Interactive Inverse Kinematics
DEFF Research Database (Denmark)
Engell-Nørregård, Morten; Erleben, Kenny
2009-01-01
Inverse kinematics is the problem of posing an articulated figure to obtain a wanted goal, without regarding inertia and forces. Joint limits are modeled as bounds on individual degrees of freedom, leading to a box-constrained optimization problem. We present A projected Non-linear Conjugate...... Gradient optimization method suitable for box-constrained optimization problems for inverse kinematics. We show application on inverse kinematics positioning of a human figure. Performance is measured and compared to a traditional Jacobian Transpose method. Visual quality of the developed method...
4. Analysis of a closed-kinematic chain robot manipulator
Science.gov (United States)
Nguyen, Charles C.; Pooran, Farhad J.
1988-01-01
Presented are the research results from the research grant entitled: Active Control of Robot Manipulators, sponsored by the Goddard Space Flight Center (NASA) under grant number NAG-780. This report considers a class of robot manipulators based on the closed-kinematic chain mechanism (CKCM). This type of robot manipulators mainly consists of two platforms, one is stationary and the other moving, and they are coupled together through a number of in-parallel actuators. Using spatial geometry and homogeneous transformation, a closed-form solution is derived for the inverse kinematic problem of the six-degree-of-freedom manipulator, built to study robotic assembly in space. Iterative Newton Raphson method is employed to solve the forward kinematic problem. Finally, the equations of motion of the above manipulators are obtained by employing the Lagrangian method. Study of the manipulator dynamics is performed using computer simulation whose results show that the robot actuating forces are strongly dependent on the mass and centroid locations of the robot links.
5. WISDOM project - I. Black hole mass measurement using molecular gas kinematics in NGC 3665
Science.gov (United States)
Onishi, Kyoko; Iguchi, Satoru; Davis, Timothy A.; Bureau, Martin; Cappellari, Michele; Sarzi, Marc; Blitz, Leo
2017-07-01
As a part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM) project, we present an estimate of the mass of the supermassive black hole (SMBH) in the nearby fast-rotator early-type galaxy NGC 3665. We obtained the Combined Array for Research in Millimeter Astronomy (CARMA) B and C array observations of the 12CO(J = 2 - 1) emission line with a combined angular resolution of 0.59 arcsec. We analysed and modelled the three-dimensional molecular gas kinematics, obtaining a best-fitting SMBH mass M_BH=5.75^{+1.49}_{-1.18} × 108 M⊙, a mass-to-light ratio at H-band (M/L)H = 1.45 ± 0.04 (M/L)⊙,H and other parameters describing the geometry of the molecular gas disc (statistical errors, all at 3σ confidence). We estimate the systematic uncertainties on the stellar M/L to be ≈0.2 (M/L)⊙,H, and on the SMBH mass to be ≈0.4 × 108 M⊙. The measured SMBH mass is consistent with that estimated from the latest correlations with galaxy properties. Following our older works, we also analysed and modelled the kinematics using only the major-axis position-velocity diagram, and conclude that the two methods are consistent.
6. Kinematic Tests of Small Arms
Science.gov (United States)
2016-03-15
muzzle devices, such as flash suppressors and muzzle compensators, if the items are designed to be operator removable. Use the ammunition that will...muzzle brake or adding a sound suppressor . A kinematics study is also a diagnostic tool to investigate weapon problems such as poor functioning with
7. FT-IR measurements of NH3 in the 1.5 μm region: line positions, intensities and their quantum assignments
Science.gov (United States)
Sung, K.; Brown, L. R.; Huang, X.; Schwenke, D. W.; Lee, T. J.
2011-12-01
As part of an effort to provide a complete set of spectroscopic line parameters of NH3 in the 1.5 μm region, we have analyzed the laboratory spectra recorded at various temperatures (200 - 299 K) with the McMath-Pierce Fourier transform spectrometer (FTS) on Kitt Peak Observatory in Arizona. The integrated sum of observed line strengths is measured to be 4.7×10-19 cm/molecule in the 6300 - 7000 cm-1 region. In this poster, we present line positions and strengths for the lines from four strong bands (2v1, 2v3, v1+v3, v1+2v4 and v3+2v4), which contribute more than 65% of opacity in the region. Lower state energies and quantum assignments determined by constructing combination differences are also presented. A theoretical IR linelist (X. Huang, D. W. Schwenke, and T. J. Lee. J. Chem. Phys., 134, 044320/044321, 2011) built upon the recent HSL-2 potential energy surface (nonadiabatic corrections included) is complementarily used for the quantum assignments. This work will support spectroscopic studies of atmospheres of outer planets, low mass brown dwarfs, and possibly extrasolar planets, in the 1.5 μm region (the H-band), where ammonia is one of significant opacity sources. (Research described in this talk was performed at Jet Propulsion Laboratory, California Institute of Technology, and was supported by the Planetary Atmospheric Research Program under the National Aeronautics and Space Administration. The AMES group acknowledges support from the NASA APRA & Herschel GO Program, and X.H. acknowledges the support by NASA/SETI Institute Co-operative Agreement.)
8. Transverse masses and kinematic constraints: from the boundary to the crease
International Nuclear Information System (INIS)
Barr, Alan J.; Gripaios, Ben; Lester, Christopher G.
2009-01-01
We re-examine the kinematic variable m T2 and its relatives in the light of recent work by Cheng and Han. Their proof that m T2 admits an equivalent, but implicit, definition as the 'boundary of the region of parent and daughter masses that is kinematically consistent with the event hypothesis' is far-reaching in its consequences. We generalize their result both to simpler cases (m T , the transverse mass) and to more complex cases (m TGen ). We further note that it is possible to re-cast many existing and unpleasant proofs (e.g. those relating to the existence or properties of 'kink' and 'crease' structures in m T2 ) into almost trivial forms by using the alternative definition. Not only does this allow us to gain better understanding of those existing results, but it also allows us to write down new (and more or less explicit) definitions of (a) the variable that naturally generalizes m T2 to the case in which the parent or daughter particles are not identical, and (b) the inverses of m T and m T2 - which may be useful if daughter masses are known and bounds on parent masses are required. We note the implications that these results may have for future matrix-element likelihood techniques.
9. On the kinematics of visual binary and multiple stars of the FK4 cataloque
International Nuclear Information System (INIS)
Starikova, G.A.
1981-01-01
Kinematic features of single, binary and multiple stars are considered. To compare kinematics of such stars with the kinematics of single stars the data on positions and proper motions of those stars which are given in the basic catalogue FK4. Single as well as visual binary and multiple stars united because of their limited content in FK4 have been subdivided by spectra and classes of luminosity into groups with account for known kinematic peculiarities of various spectral groups. Kinematic features for the studied spectral groups are given. By the stars of the FK4 catalogue for various spectral classes the difference of kinematic features of single, visual binary and multiple stars is obtained. However the values of these differences need to be specified due to small number of stars included in five of six groups considered
10. A real-time computational model for estimating kinematics of ankle ligaments.
Science.gov (United States)
Zhang, Mingming; Davies, T Claire; Zhang, Yanxin; Xie, Sheng Quan
2016-01-01
An accurate assessment of ankle ligament kinematics is crucial in understanding the injury mechanisms and can help to improve the treatment of an injured ankle, especially when used in conjunction with robot-assisted therapy. A number of computational models have been developed and validated for assessing the kinematics of ankle ligaments. However, few of them can do real-time assessment to allow for an input into robotic rehabilitation programs. An ankle computational model was proposed and validated to quantify the kinematics of ankle ligaments as the foot moves in real-time. This model consists of three bone segments with three rotational degrees of freedom (DOFs) and 12 ankle ligaments. This model uses inputs for three position variables that can be measured from sensors in many ankle robotic devices that detect postures within the foot-ankle environment and outputs the kinematics of ankle ligaments. Validation of this model in terms of ligament length and strain was conducted by comparing it with published data on cadaver anatomy and magnetic resonance imaging. The model based on ligament lengths and strains is in concurrence with those from the published studies but is sensitive to ligament attachment positions. This ankle computational model has the potential to be used in robot-assisted therapy for real-time assessment of ligament kinematics. The results provide information regarding the quantification of kinematics associated with ankle ligaments related to the disability level and can be used for optimizing the robotic training trajectory.
11. Differences in foot kinematics between young and older adults during walking.
Science.gov (United States)
Arnold, John B; Mackintosh, Shylie; Jones, Sara; Thewlis, Dominic
2014-02-01
12. THE ARIZONA RADIO OBSERVATORY CO MAPPING SURVEY OF GALACTIC MOLECULAR CLOUDS. I. THE W51 REGION IN CO AND 13CO J = 2-1 EMISSION
International Nuclear Information System (INIS)
Bieging, John H.; Peters, William L.; Kang, Miju
2010-01-01
We present 38'' resolution maps of the CO and 13 CO J = 2-1 lines in the molecular clouds toward the H II region complex W51. The maps cover a 1. 0 25 x 1 0 section of the galactic plane and span +30 to +85 km s -1 (LSR) in velocity. The spectral resolution is ∼1.3 km s -1 . The velocity range of the images includes all the gas in the Sagittarius spiral arm. Color figures display the peak line brightness temperature, the velocity-integrated intensity, and 2 km s -1 channel-averaged maps for both isotopologs, and also the CO/ 13 CO J = 2-1 line intensity ratio as a function of velocity. The CO and 13 CO line intensity image cubes are made available in standard FITS format as electronically readable tables. We compare our molecular line maps with the 1.1 mm continuum image from the BOLOCAM Galactic Plane Survey. From our 13 CO image cube, we derive kinematic information for the 99 BGPS sources in the mapped field in the form of Gaussian component fits. The integrated 13 CO line intensity and the 1.1 mm source flux density show only a modest degree of correlation for the 99 sources, likely due to a range of dust and gas physical conditions within the sources. However, the 1.1 mm continuum surface brightness and the integrated 13 CO line intensity for small regions containing single BGPS sources and molecular clouds show very good correlations in many cases. Differences in the shapes of these correlations from one spatial region to another probably result from different physical conditions or structure in the clouds.
13. Kinematic Modeling of Distant Galaxies
Directory of Open Access Journals (Sweden)
Kipper Rain
2012-12-01
Full Text Available Evolution of galaxies is one of the most actual topics in astrophysics. Among the most important factors determining the evolution are two galactic components which are difficult or even impossible to detect optically: the gaseous disks and the dark matter halo. We use deep Hubble Space Telescope images to construct a two-component (bulge + disk model for stellar matter distribution of galaxies. Properties of the galactic components are derived using a three-dimensional galaxy modeling software, which also estimates disk thickness and inclination angle. We add a gas disk and a dark matter halo and use hydrodynamical equations to calculate gas rotation and dispersion profiles in the resultant gravitational potential. We compare the kinematic profiles with the Team Keck Redshift Survey observations. In this pilot study, two galaxies are analyzed deriving parameters for their stellar components; both galaxies are found to be disk-dominated. Using the kinematical model, the gas mass and stellar mass ratio in the disk are estimated.
14. Numerical simulations of sheared magnetic lines at the solar null line
Science.gov (United States)
Kuźma, B.; Murawski, K.; Solov'ev, A.
2015-05-01
Aims: We perform numerical simulations of sheared magnetic lines at the magnetic null line configuration of two magnetic arcades that are settled in a gravitationally stratified and magnetically confined solar corona. Methods: We developed a general analytical model of a 2.5D solar atmospheric structure. As a particular application of this model, we adopted it for the curved magnetic field lines with an inverted Y shape that compose the null line above two magnetic arcades, which are embedded in the solar atmosphere that is specified by the realistic temperature distribution. The physical system is described by 2.5D magnetohydrodynamic equations that are numerically solved by the FLASH code. Results: The magnetic field line shearing, implemented about 200 km below the transition region, results in Alfvén and magnetoacoustic waves that are able to penetrate solar coronal regions above the magnetic null line. As a result of the coupling of these waves, partial reflection from the transition region and scattering from inhomogeneous regions the Alfvén waves experience fast attenuation on time scales comparable to their wave periods, and the physical system relaxes in time. The attenuation time grows with the large amplitude and characteristic growing time of the shearing. Conclusions: By having chosen a different magnetic flux function, the analytical model we devised can be adopted to derive equilibrium conditions for a diversity of 2.5D magnetic structures in the solar atmosphere. Movie associated to Fig. 5 is available in electronic form at http://www.aanda.org
15. Adaptive control of an exoskeleton robot with uncertainties on kinematics and dynamics.
Science.gov (United States)
Brahmi, Brahim; Saad, Maarouf; Ochoa-Luna, Cristobal; Rahman, Mohammad H
2017-07-01
In this paper, we propose a new adaptive control technique based on nonlinear sliding mode control (JSTDE) taking into account kinematics and dynamics uncertainties. This approach is applied to an exoskeleton robot with uncertain kinematics and dynamics. The adaptation design is based on Time Delay Estimation (TDE). The proposed strategy does not necessitate the well-defined dynamic and kinematic models of the system robot. The updated laws are designed using Lyapunov-function to solve the adaptation problem systematically, proving the close loop stability and ensuring the convergence asymptotically of the outputs tracking errors. Experiments results show the effectiveness and feasibility of JSTDE technique to deal with the variation of the unknown nonlinear dynamics and kinematics of the exoskeleton model.
16. Constraining The Abundance Of Massive Black Hole Binaries By Spectroscopic Monitoring Of Quasars With Offset Broad Emission Lines
Science.gov (United States)
Liu, Xin; Shen, Y.
2012-05-01
A fraction of quasars have long been known to show significant bulk velocity offsets (of a few hundred to thousands of km/s) in the broad permitted emission lines with respect to host galaxy systemic redshift. Various scenarios may explain these features such as massive black hole binaries or broad line region gas kinematics. As previously demonstrated by the dedicated work of Eracleous and colleagues, long-term spectroscopic monitoring provides a promising test to discriminate between alternative scenarios. Here, we present a sample of 300 shifted-line quasars homogeneously selected from the SDSS DR7. For 60 of them, we have conducted second-epoch optical spectra using MMT/BCS, ARC 3.5m/DIS, and/or FLWO 1.5m/FAST. These new observations, combined with the existing SDSS spectra, enable us to constrain the velocity drifts of these shifted broad lines with time baselines of a few years up to a decade. Previous work has been focusing on objects with extreme velocity offsets: > 1000 km/s. Our work extends to the parameter space of smaller velocity offsets, where larger velocity drifts would be expected in the binary scenario. Our results may be used to identify strong candidates for and to constrain the abundance of massive black hole binaries, which are expected in the hierarchical universe, but have so far been illusive.
17. A School Experiment in Kinematics: Shooting from a Ballistic Cart
Science.gov (United States)
Kranjc, T.; Razpet, N.
2011-01-01
Many physics textbooks start with kinematics. In the lab, students observe the motions, describe and make predictions, and get acquainted with basic kinematics quantities and their meaning. Then they can perform calculations and compare the results with experimental findings. In this paper we describe an experiment that is not often done, but is…
18. Right-handed currents at B→ K l+l− kinematic endpoint
Indian Academy of Sciences (India)
2017-10-09
Oct 9, 2017 ... The recent LHCb measured values of these observables are used to conclude an evidence of right-handed currents at the kinematic endpoint of this decay mode. As the conclusion is drawn at the maximum dilepton invariant mass square ( q 2 ) kinematic endpoint, it relies only on heavy quark symmetries ...
19. Kinematic Analysis of 3-DOF Planer Robot Using Artificial Neural Network
Directory of Open Access Journals (Sweden)
Jolly Atit Shah
2012-07-01
Full Text Available Automatic control of the robotic manipulator involves study of kinematics and dynamics as a major issue. This paper involves the forward and inverse kinematics of 3-DOF robotic manipulator with revolute joints. In this study the Denavit- Hartenberg (D-H model is used to model robot links and joints. Also forward and inverse kinematics solution has been achieved using Artificial Neural Networks for 3-DOF robotic manipulator. It shows that by using artificial neural network the solution we get is faster, acceptable and has zero error.
20. Tibial rotation kinematics subsequent to knee arthroplasty
Science.gov (United States)
Collins, Duane J.; Khatib, Yasser H.; Parker, David A.; Jenkin, Deanne E.; Molnar, Robert B.
2015-01-01
Background The use of computer assisted joint replacement has facilitated precise intraoperative measurement of knee kinematics. The changes in “screw home mechanism” (SHM) resulting from Total Knee Arthroplasty (TKA) with different prostheses and constraints has not yet been accurately described. Methods A pilot study was first completed. Intraoperative kinematic data was collected two groups of 15 patients receiving different prostheses. Results On average, patients lost 5.3° of ER (SD = 6.1°). There was no significant difference between the prostheses or different prosthetic constraints. Conclusions There significant loss of SHM after TKA. Further research is required to understand its impact on patient function. PMID:25829754
1. Hemodiafiltration using pre-dilutional on-line citrate dialysate: A new technique for regional citrate anticoagulation: A feasibility study
Directory of Open Access Journals (Sweden)
2015-01-01
Full Text Available A prospective, observational, feasibility study was carried out on four patients with end-stage renal failure undergoing bicarbonate hemodialysis to study the feasibility of an on-line hemodiafiltration technique using a citrate dialysate with pre-dilutional infusion of citrate as a technique for regional citrate anticoagulation. All patients had contraindication to systemic heparin anticoagulation. The dialysis technique consisted of an on-line hemodiafiltration with a citrate dialysate without calcium using a Fresenius 4008S dialysis machine and Fresenius Polysulfone F60 dialyzers. The infusion solution was procured directly from the dialysate and was infused into the arterial line. To avoid the risk of hypocalcemia, calcium gluconate was infused to the venous return line. The study was carried out in two stages. During the first stage, the citrate infusion rate was 80 mL/min and the calcium infusion rate was 9 mmol/h. At the second stage, the rates were 100 mL/min and 11 mmol/h, respectively. The primary endpoint of this study was the incidence of thrombosis in the extracorporeal blood circuit and/or the dialyzer. A total of 78 sessions were conducted. All the sessions were well tolerated clinically and there were no major incidents in any of the four patients. At the first stage of the study, there were five incidences of small clots in the venous blood chamber, an incidence of extracorporeal blood circuit thrombosis of 12.5%. At the second stage of the study, no cases of extracorporeal blood circuit or dialyzer thrombosis were noted. Hemodiafiltration with on-line citrate dialysate infusion to the arterial line is safe and allows an effective regional anticoagulation of the extracorporeal blood circuit without the need for systemic anticoagulation.
2. Kinematic Analysis of Speech Sound Sequencing Errors Induced by Delayed Auditory Feedback.
Science.gov (United States)
Cler, Gabriel J; Lee, Jackson C; Mittelman, Talia; Stepp, Cara E; Bohland, Jason W
2017-06-22
Delayed auditory feedback (DAF) causes speakers to become disfluent and make phonological errors. Methods for assessing the kinematics of speech errors are lacking, with most DAF studies relying on auditory perceptual analyses, which may be problematic, as errors judged to be categorical may actually represent blends of sounds or articulatory errors. Eight typical speakers produced nonsense syllable sequences under normal and DAF (200 ms). Lip and tongue kinematics were captured with electromagnetic articulography. Time-locked acoustic recordings were transcribed, and the kinematics of utterances with and without perceived errors were analyzed with existing and novel quantitative methods. New multivariate measures showed that for 5 participants, kinematic variability for productions perceived to be error free was significantly increased under delay; these results were validated by using the spatiotemporal index measure. Analysis of error trials revealed both typical productions of a nontarget syllable and productions with articulatory kinematics that incorporated aspects of both the target and the perceived utterance. This study is among the first to characterize articulatory changes under DAF and provides evidence for different classes of speech errors, which may not be perceptually salient. New methods were developed that may aid visualization and analysis of large kinematic data sets. https://doi.org/10.23641/asha.5103067.
3. Synthetic tsunami waveform catalogs with kinematic constraints
Science.gov (United States)
Baptista, Maria Ana; Miranda, Jorge Miguel; Matias, Luis; Omira, Rachid
2017-07-01
In this study we present a comprehensive methodology to produce a synthetic tsunami waveform catalogue in the northeast Atlantic, east of the Azores islands. The method uses a synthetic earthquake catalogue compatible with plate kinematic constraints of the area. We use it to assess the tsunami hazard from the transcurrent boundary located between Iberia and the Azores, whose western part is known as the Gloria Fault. This study focuses only on earthquake-generated tsunamis. Moreover, we assume that the time and space distribution of the seismic events is known. To do this, we compute a synthetic earthquake catalogue including all fault parameters needed to characterize the seafloor deformation covering the time span of 20 000 years, which we consider long enough to ensure the representability of earthquake generation on this segment of the plate boundary. The computed time and space rupture distributions are made compatible with global kinematic plate models. We use the tsunami empirical Green's functions to efficiently compute the synthetic tsunami waveforms for the dataset of coastal locations, thus providing the basis for tsunami impact characterization. We present the results in the form of offshore wave heights for all coastal points in the dataset. Our results focus on the northeast Atlantic basin, showing that earthquake-induced tsunamis in the transcurrent segment of the Azores-Gibraltar plate boundary pose a minor threat to coastal areas north of Portugal and beyond the Strait of Gibraltar. However, in Morocco, the Azores, and the Madeira islands, we can expect wave heights between 0.6 and 0.8 m, leading to precautionary evacuation of coastal areas. The advantages of the method are its easy application to other regions and the low computation effort needed.
4. The Three-Dimensional Morphology of VY Canis Majoris. I. The Kinematics of the Ejecta
Science.gov (United States)
Humphreys, Roberta M.; Helton, L. Andrew; Jones, Terry J.
2007-06-01
Images of the complex circumstellar nebula associated with the famous red supergiant VY CMa show evidence for multiple and asymmetric mass-loss events over the past 1000 yr. Doppler velocities of the arcs and knots in the ejecta show that they are not only spatially distinct but also kinematically separate from the surrounding diffuse material. In this paper we describe second-epoch HST WFPC2 images to measure the transverse motions, which when combined with the radial motions provide a complete picture of the kinematics of the ejecta, including the total space motions and directions of the outflows. Our results show that the arcs and clumps of knots are moving at different velocities, in different directions, and at different angles relative to the plane of the sky and to the star, confirming their origin from eruptions at different times and from physically separate regions on the star. We conclude that the morphology and kinematics of the arcs and knots are consistent with a history of mass ejections not aligned with any presumed axis of symmetry. The arcs and clumps represent relatively massive outflows and ejections of gas very likely associated with large-scale convective activity and magnetic fields. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.
5. PHIBSS: MOLECULAR GAS, EXTINCTION, STAR FORMATION, AND KINEMATICS IN THE z = 1.5 STAR-FORMING GALAXY EGS13011166
Energy Technology Data Exchange (ETDEWEB)
Genzel, R.; Tacconi, L. J.; Kurk, J.; Wuyts, S.; Foerster Schreiber, N. M.; Gracia-Carpio, J. [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Giessenbachstr., D-85748 Garching (Germany); Combes, F.; Freundlich, J. [Observatoire de Paris, LERMA, CNRS, 61 Av. de l' Observatoire, F-75014 Paris (France); Bolatto, A. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Cooper, M. C. [Department of Physics and Astronomy, Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Neri, R. [IRAM, 300 Rue de la Piscine, F-38406 St. Martin d' Heres, Grenoble (France); Nordon, R. [Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Bournaud, F. [Service d' Astrophysique, DAPNIA, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex (France); Burkert, A. [Universitaetssternwarte der Ludwig-Maximiliansuniversitaet, Scheinerstr. 1, D-81679 Muenchen (Germany); Comerford, J. [Department of Astronomy and McDonald Observatory, 1 University Station, C1402 Austin, TX 78712-0259 (United States); Cox, P. [Department of Physics, Le Conte Hall, University of California, 94720 Berkeley, CA (United States); Davis, M. [Department of Astronomy, Campbell Hall, University of California, Berkeley, CA 94720 (United States); Garcia-Burillo, S. [Observatorio Astronomico Nacional-OAN, Observatorio de Madrid, Alfonso XII, 3, E-28014 Madrid (Spain); Naab, T. [Max-Planck Institut fuer Astrophysik, Karl Schwarzschildstrasse 1, D-85748 Garching (Germany); Lutz, D., E-mail: genzel@mpe.mpg.de, E-mail: linda@mpe.mpg.de; and others
2013-08-10
We report matched resolution imaging spectroscopy of the CO 3-2 line (with the IRAM Plateau de Bure millimeter interferometer) and of the H{alpha} line (with LUCI at the Large Binocular Telescope) in the massive z = 1.53 main-sequence galaxy EGS 13011166, as part of the ''Plateau de Bure high-z, blue-sequence survey'' (PHIBSS: Tacconi et al.). We combine these data with Hubble Space Telescope V-I-J-H-band maps to derive spatially resolved distributions of stellar surface density, star formation rate, molecular gas surface density, optical extinction, and gas kinematics. The spatial distribution and kinematics of the ionized and molecular gas are remarkably similar and are well modeled by a turbulent, globally Toomre unstable, rotating disk. The stellar surface density distribution is smoother than the clumpy rest-frame UV/optical light distribution and peaks in an obscured, star-forming massive bulge near the dynamical center. The molecular gas surface density and the effective optical screen extinction track each other and are well modeled by a ''mixed'' extinction model. The inferred slope of the spatially resolved molecular gas to star formation rate relation, N = dlog{Sigma}{sub starform}/dlog{Sigma}{sub molgas}, depends strongly on the adopted extinction model, and can vary from 0.8 to 1.7. For the preferred mixed dust-gas model, we find N = 1.14 {+-} 0.1.
6. Numerical kinematic transformation calculations for a parallel link manipulator
International Nuclear Information System (INIS)
Killough, S.M.
1993-01-01
Parallel link manipulators are often considered for particular robotic applications because of the unique advantages they provide. Unfortunately, they have significant disadvantages with respect to calculating the kinematic transformations because of the high-order equations that must be solved. Presented is a manipulator design that exploits the mechanical advantages of parallel links yet also has a corresponding numerical kinematic solution that can be solved in real time on common microcomputers
7. Assessing distances and consistency of kinematics in Gaia/TGAS
Science.gov (United States)
Schönrich, Ralph; Aumer, Michael
2017-12-01
We apply the statistical methods by Schönrich, Binney & Asplund to assess the quality of distances and kinematics in the Radial Velocity Experiment (RAVE)-Tycho-Gaia Astrometric Solution (TGAS) and Large Sky Area Multiobject Fiber Spectroscopic Telescope (LAMOST)-TGAS samples of Solar neighbourhood stars. These methods yield a nominal distance accuracy of 1-2 per cent. Other than common tests on parallax accuracy, they directly test distance estimations including the effects of distance priors. We show how to construct these priors including the survey selection functions (SSFs) directly from the data. We demonstrate that neglecting the SSFs causes severe distance biases. Due to the decline of the SSFs in distance, the simple 1/parallax estimate only mildly underestimates distances. We test the accuracy of measured line-of-sight velocities (vlos) by binning the samples in the nominal vlos uncertainties. We find: (i) the LAMOST vlos have a ∼-5 km s-1 offset; (ii) the average LAMOST measurement error for vlos is ∼7 km s-1, significantly smaller than, and nearly uncorrelated with the nominal LAMOST estimates. The RAVE sample shows either a moderate distance underestimate, or an unaccounted source of vlos dispersion (e∥) from measurement errors and binary stars. For a subsample of suspected binary stars in RAVE, our methods indicate significant distance underestimates. Separating a sample in metallicity or kinematics to select thick-disc/halo stars, discriminates between distance bias and e∥. For LAMOST, this separation yields consistency with pure vlos measurement errors. We find an anomaly near longitude l ∼ (300 ± 60)° and distance s ∼ (0.32 ± 0.03) kpc on both sides of the galactic plane, which could be explained by either a localized distance error or a breathing mode.
8. A non-linear kinematic hardening function
International Nuclear Information System (INIS)
Ottosen, N.S.
1977-05-01
Based on the classical theory of plasticity, and accepting the von Mises criterion as the initial yield criterion, a non-linear kinematic hardening function applicable both to Melan-Prager's and to Ziegler's hardening rule is proposed. This non-linear hardening function is determined by means of the uniaxial stress-strain curve, and any such curve is applicable. The proposed hardening function considers the problem of general reversed loading, and a smooth change in the behaviour from one plastic state to another nearlying plastic state is obtained. A review of both the kinematic hardening theory and the corresponding non-linear hardening assumptions is given, and it is shown that material behaviour is identical whether Melan-Prager's or Ziegler's hardening rule is applied, provided that the von Mises yield criterion is adopted. (author)
9. A REVISED BROAD-LINE REGION RADIUS AND BLACK HOLE MASS FOR THE NARROW-LINE SEYFERT 1 NGC 4051
International Nuclear Information System (INIS)
Denney, K. D.; Watson, L. C.; Peterson, B. M.
2009-01-01
We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of this campaign was to obtain either new or improved Hβ reverberation lag measurements for several relatively low luminosity active galactic nuclei (AGNs). We feature results for NGC 4051 here because, until now, this object has been a significant outlier from AGN scaling relationships, e.g., it was previously a ∼2-3σ outlier on the relationship between the broad-line region (BLR) radius and the optical continuum luminosity-the R BLR -L relationship. Our new measurements of the lag time between variations in the continuum and Hβ emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R BLR = 1.87 +0.54 -0.50 light days and black hole mass of M BH = (1.73 +0.55 -0.52 ) x 10 6 M sun . This radius is consistent with that expected from the R BLR -L relationship, based on the present luminosity of NGC 4051 and the most current calibration of the relation by Bentz et al.. We also present a preliminary look at velocity-resolved Hβ light curves and time delay measurements, although we are unable to reconstruct an unambiguous velocity-resolved reverberation signal.
10. Mass density slope of elliptical galaxies from strong lensing and resolved stellar kinematics
Science.gov (United States)
Lyskova, N.; Churazov, E.; Naab, T.
2018-04-01
We discuss constraints on the mass density distribution (parametrized as ρ ∝ r-γ) in early-type galaxies provided by strong lensing and stellar kinematics data. The constraints come from mass measurements at two pinch' radii. One pinch' radius r1 = 2.2REinst is defined such that the Einstein (i.e. aperture) mass can be converted into the spherical mass almost independently of the mass-model. Another pinch' radius r2 = Ropt is chosen so that the dynamical mass, derived from the line-of-sight velocity dispersion, is least sensitive to the anisotropy of stellar orbits. We verified the performance of this approach on a sample of simulated elliptical galaxies and on a sample of 15 SLACS lens galaxies at 0.01 ≤ z ≤ 0.35, which have already been analysed in Barnabè et al. by the self-consistent joint lensing and kinematic code. For massive simulated galaxies, the density slope γ is recovered with an accuracy of ˜13 per cent, unless r1 and r2 happen to be close to each other. For SLACS galaxies, we found good overall agreement with the results of Barnabè et al. with a sample-averaged slope γ = 2.1 ± 0.05. Although the two-pinch-radii approach has larger statistical uncertainties, it is much simpler and uses only few arithmetic operations with directly observable quantities.
11. Adding Image Constraints to Inverse Kinematics for Human Motion Capture
Science.gov (United States)
Jaume-i-Capó, Antoni; Varona, Javier; González-Hidalgo, Manuel; Perales, Francisco J.
2009-12-01
In order to study human motion in biomechanical applications, a critical component is to accurately obtain the 3D joint positions of the user's body. Computer vision and inverse kinematics are used to achieve this objective without markers or special devices attached to the body. The problem of these systems is that the inverse kinematics is "blinded" with respect to the projection of body segments into the images used by the computer vision algorithms. In this paper, we present how to add image constraints to inverse kinematics in order to estimate human motion. Specifically, we explain how to define a criterion to use images in order to guide the posture reconstruction of the articulated chain. Tests with synthetic images show how the scheme performs well in an ideal situation. In order to test its potential in real situations, more experiments with task specific image sequences are also presented. By means of a quantitative study of different sequences, the results obtained show how this approach improves the performance of inverse kinematics in this application.
12. Is Active Tectonics on Madagascar Consistent with Somalian Plate Kinematics?
Science.gov (United States)
Stamps, D. S.; Kreemer, C.; Rajaonarison, T. A.
2017-12-01
The East African Rift System (EARS) actively breaks apart the Nubian and Somalian tectonic plates. Madagascar finds itself at the easternmost boundary of the EARS, between the Rovuma block, Lwandle plate, and the Somalian plate. Earthquake focal mechanisms and N-S oriented fault structures on the continental island suggest that Madagascar is experiencing east-west oriented extension. However, some previous plate kinematic studies indicate minor compressional strains across Madagascar. This inconsistency may be due to uncertainties in Somalian plate rotation. Past estimates of the rotation of the Somalian plate suffered from a poor coverage of GPS stations, but some important new stations are now available for a re-evaluation. In this work, we revise the kinematics of the Somalian plate. We first calculate a new GPS velocity solution and perform block kinematic modeling to evaluate the Somalian plate rotation. We then estimate new Somalia-Rovuma and Somalia-Lwandle relative motions across Madagascar and evaluate whether they are consistent with GPS measurements made on the island itself, as well as with other kinematic indicators.
13. Interrogating Seyferts with NebulaBayes: Spatially Probing the Narrow-line Region Radiation Fields and Chemical Abundances
Science.gov (United States)
Thomas, Adam D.; Dopita, Michael A.; Kewley, Lisa J.; Groves, Brent A.; Sutherland, Ralph S.; Hopkins, Andrew M.; Blanc, Guillermo A.
2018-04-01
NebulaBayes is a new Bayesian code that implements a general method of comparing observed emission-line fluxes to photoionization model grids. The code enables us to extract robust, spatially resolved measurements of abundances in the extended narrow-line regions (ENLRs) produced by Active Galactic Nuclei (AGN). We observe near-constant ionization parameters but steeply radially declining pressures, which together imply that radiation pressure regulates the ENLR density structure on large scales. Our sample includes four “pure Seyfert” galaxies from the S7 survey that have extensive ENLRs. NGC 2992 shows steep metallicity gradients from the nucleus into the ionization cones. An inverse metallicity gradient is observed in ESO 138-G01, which we attribute to a recent gas inflow or minor merger. A uniformly high metallicity and hard ionizing continuum are inferred across the ENLR of Mrk 573. Our analysis of IC 5063 is likely affected by contamination from shock excitation, which appears to soften the inferred ionizing spectrum. The peak of the ionizing continuum E peak is determined by the nuclear spectrum and the absorbing column between the nucleus and the ionized nebula. We cannot separate variation in this intrinsic E peak from the effects of shock or H II region contamination, but E peak measurements nevertheless give insights into ENLR excitation. We demonstrate the general applicability of NebulaBayes by analyzing a nuclear spectrum from the non-active galaxy NGC 4691 using a H II region grid. The NLR and H II region model grids are provided with NebulaBayes for use by the astronomical community.
14. Fatigue effects on bar kinematics during the bench press.
Science.gov (United States)
Duffey, Michael J; Challis, John H
2007-05-01
The bench press is one of the most popular weight training exercises. Although most training regimens incorporate multiple repetition sets, there are few data describing how the kinematics of a lift change during a set to failure. To examine these changes, recreational lifters (10 men and 8 women) were recruited. The maximum weight each subject could bench press (1RM) was determined. Subjects then performed as many repetitions as possible at 75% of the 1RM load. Three-dimensional kinematic data were recorded and analyzed for all lifts. Statistical analysis revealed that differences between maximal and submaximal lifts and the kinematics of a submaximal lift change as a subject approaches failure in a set. The time to lift the bar more than doubled from the first to the last repetition, causing a decrease in both mean and peak upward velocity. Furthermore, the peak upward velocity occurred much earlier in the lift phase in these later repetitions. The path the bar followed also changed, with subjects keeping the bar more directly over the shoulder during the lift. In general, most of the kinematic variables analyzed became more similar to those of the maximal lift as the subjects progressed through the set, but there was considerable variation between subjects as to which repetition was most like the maximal lift. This study shows that there are definite changes in the lifting kinematics in recreational lifters during a set to failure and suggests it may be particularly important for coaches and less-skilled lifters to focus on developing the proper bar path, rather than reaching momentary muscular failure, in the early part of a training program.
15. KINEMATICS AND DYNAMICS MODELS OF CYLINDRICAL ROLLER BEARING OF RAILWAY TRANSPORT
Directory of Open Access Journals (Sweden)
A. V. Gaydamaka
2014-05-01
Full Text Available Purpose. Lack of kinematics models and imperfection of the known dynamics models of the roller bearings of railway rolling stock axle-boxes do not allow designing the optimal structure of bearing cages, providing the required service life and reliability of bearing units of wheel sets for cars and locomotives. The studies of kinematics and dynamics of roller bearings of axle boxes for cars and locomotives and modeling of their parts interaction to create the analytical method of bearing cages calculation are necessary. Methodology. This purpose has been achieved due to the modeling of kinematics of the ideal (without gaps and real (taking account the gaps, manufacturing and installation errors bearings, substantiation of the transfer mechanism of motion from the rollers to bearing cage, modeling the dynamics of rolling, research of interaction forces of the rollers with bearing cage. Findings. It is established that the kinematics of ideal bearing is determined by the contact deformations of the rollers and rings, when the kinematics of real bearing depends mainly on the side gaps in the windows of the bearing cage. On the basis of studies of the real bearing kinematics the dynamics models of the rollers and bearing cage interaction were constructed. The conducted studies of kinematics and dynamics of rolling bearings have changed our view of them as of the planetary mechanism, explained the reason of bearing cage loading, and confirmed the possibility of destruction during operation. Originality. It was first proposed a mechanism for motion transfer from the rollers to the bearing cage of roller bearings, consisting in that the side gap in the bearing cage window is reduced gradually multiple of the number of rollers of radial loading area according to the bearing cage motion. The models of roller bearing dynamics, which allow calculating the interaction forces of parts for all modes of operation, were improved. Practical value. Use of the
16. Isolated patellofemoral arthroplasty reproduces natural patellofemoral joint kinematics when the patella is resurfaced.
Science.gov (United States)
Vandenneucker, Hilde; Labey, Luc; Vander Sloten, Jos; Desloovere, Kaat; Bellemans, Johan
2016-11-01
The objectives of this in vitro project were to compare the dynamic three-dimensional patellofemoral kinematics, contact forces, contact areas and contact pressures of a contemporary patellofemoral prosthetic implant with those of the native knee and to measure the influence of patellar resurfacing and patellar thickness. The hypothesis was that these designs are capable to reproduce the natural kinematics but result in higher contact pressures. Six fresh-frozen specimens were tested on a custom-made mechanical knee rig before and after prosthetic trochlear resurfacing, without and with patellar resurfacing in three different patellar thicknesses. Full three-dimensional kinematics were analysed during three different motor tasks, using infrared motion capture cameras and retroflective markers. Patellar contact characteristics were registered using a pressure measuring device. The patellofemoral kinematic behaviour of the patellofemoral arthroplasty was similar to that of the normal knee when the patella was resurfaced, showing only significant (p patellofemoral kinematics acceptable well when the patella was resurfaced. From a kinematic point of view, patellar resurfacing may be advisable. However, the substantially elevated patellar contact pressures remain a point of concern in the decision whether or not to resurface the patella. This study therefore not only adds a new point in the discussion whether or not to resurface the patella, but also supports the claimed advantage that a patellofemoral arthroplasty is capable to reproduce the natural knee kinematics.
17. Long-term strain accommodation in the eastern margin of the Tibetan Plateau: Insights from 3D thermo-kinematic modelling
Science.gov (United States)
Tian, Y.; Vermeesch, P.; Carter, A.; Zhang, P.
2017-12-01
The Cenozoic deformation of the Tibetan Plateau were dominated by the north-south collision between the Indian and Eurasian continents since Early Cenozoic time. Numerous lines of evidence suggest that the plateau has expanded outward after the collision, forming a diverging stress-regime from the collisional belt to plateau margins. When and how the expansional strain had propagated to the current plateau margins has been hotly debated. This work presents results of an on-going projects for understanding the long-term strain history along the Longmen Shan, the eastern margin of the Tibetan Plateau, where deformation is controlled by three parallel NW-dipping faults. From foreland (southeast) to hinterland (northwest), the main faults are the Guanxian-Anxian fault, Yingxiu-Beichuan fault and Wenchuan-Maowen fault. Exhumation pattern constrained by one-dimensional modelling made from a compilation of published and unpublished thermochronometry data shows a strong structural control, with highest amounts of exhumation in the hinterland region, a pattern that is characteristic of out-of-sequence reverse faulting (Tian et al., 2013, Tectonics, doi:10.1002/tect.20043; Tian et al., 2015, Geophys. Res. Lett., doi:10.1002/2014GL062383). Three-dimensional thermo-kinematic modelling of these data suggests that the Longmen Shan faults are listric in geometry, merging into a detachment at a depth of 20-30 km. The models require a marked decrease in slip-rate along the frontal Yingxiu-Beichuan in the late Miocene, whereas the slip-rate along the hinterland Wenchuan-Maowen fault remained relatively constant since early Miocene time. The long-term pattern of strain accommodation revealed by the three-dimensional thermo-kinematic modelling have important implications for distinguishing geodynamic models proposed for explaining the eastward growth of the Tibetan Plateau.
18. On open and closed field line regions in Tsyganenko's field model and their possible associations with horse collar auroras
Science.gov (United States)
Birn, J.; Hones, E. W., Jr.; Craven, J. D.; Frank, L. A.; Elphinstone, R. D.; Stern, D. P.
1991-01-01
The boundary between open and closed field lines is investigated in the empirical Tsyganenko (1987) magnetic field model. All field lines extending to distances beyond -70 R(E), the tailward velocity limit of the Tsyganenko model are defined as open, while all other field lines, which cross the equatorial plane earthward of -70 R(E) and are connected with the earth at both ends, are assumed closed. It is found that this boundary at the surface of the earth, identified as the polar cap boundary, can exhibit the arrowhead shape, pointed toward the sun, which is found in horse collar auroras. For increasing activity levels, the polar cap increases in area and becomes rounder, so that the arrowhead shape is less pronounced. The presence of a net B(y) component can also lead to considerable rounding of the open flux region. The arrowhead shape is found to be closely associated with the increase of B(z) from the midnight region to the flanks of the tail, consistent with a similar increase of the plasma sheet thickness.
19. Climbing fibers predict movement kinematics and performance errors.
Science.gov (United States)
Streng, Martha L; Popa, Laurentiu S; Ebner, Timothy J
2017-09-01
Requisite for understanding cerebellar function is a complete characterization of the signals provided by complex spike (CS) discharge of Purkinje cells, the output neurons of the cerebellar cortex. Numerous studies have provided insights into CS function, with the most predominant view being that they are evoked by error events. However, several reports suggest that CSs encode other aspects of movements and do not always respond to errors or unexpected perturbations. Here, we evaluated CS firing during a pseudo-random manual tracking task in the monkey ( Macaca mulatta ). This task provides extensive coverage of the work space and relative independence of movement parameters, delivering a robust data set to assess the signals that activate climbing fibers. Using reverse correlation, we determined feedforward and feedback CSs firing probability maps with position, velocity, and acceleration, as well as position error, a measure of tracking performance. The direction and magnitude of the CS modulation were quantified using linear regression analysis. The major findings are that CSs significantly encode all three kinematic parameters and position error, with acceleration modulation particularly common. The modulation is not related to "events," either for position error or kinematics. Instead, CSs are spatially tuned and provide a linear representation of each parameter evaluated. The CS modulation is largely predictive. Similar analyses show that the simple spike firing is modulated by the same parameters as the CSs. Therefore, CSs carry a broader array of signals than previously described and argue for climbing fiber input having a prominent role in online motor control. NEW & NOTEWORTHY This article demonstrates that complex spike (CS) discharge of cerebellar Purkinje cells encodes multiple parameters of movement, including motor errors and kinematics. The CS firing is not driven by error or kinematic events; instead it provides a linear representation of each
20. The Chandra HRC View of the Subarcsecond Structures in the Nuclear Region of NGC 1068
Science.gov (United States)
Wang, Junfeng; Fabbiano, Giuseppina; Karovska, Margarita; Elvis, Martin; Risaliti, Guido
2012-09-01
We have obtained a high spatial resolution X-ray image of the nucleus of NGC 1068 using the High Resolution Camera (HRC-I) on board the Chandra X-ray Observatory, which provides an unprecedented view of the innermost 1 arcsec radius region of this galaxy. The HRC image resolves the narrow-line region into X-ray emission clumps matching bright emission-line clouds in the HST [OIII] λ5007 images and allows comparison with subarcsecond-scale radio jet for the first time. Two distinct X-ray knots are revealed at 1.3-1.4 arcsec northeast and southwest of the nucleus. Based on the combined X-ray, [O III], and radio continuum morphology, we identify the locations of intense radio jet-cloud interaction. The [O III] to soft X-ray ratios show that some of these clouds are strongly affected by shock heating, whereas in other locations the jet simply thrusts through with no signs of strong interaction. This is further strengthened by the presence of a kT ~ 1 keV collisionally ionized component in the ACIS spectrum of a shock-heated cloud HST-G. We estimate that the kinematic luminosity of the jet-driven shocks is 6 × 1038 erg s-1, a negligible fraction (10-4) of the estimated total jet power.
1. Kinematics of roller chain drives - Exact and approximate analysis
DEFF Research Database (Denmark)
Fuglede, Niels; Thomsen, Jon Juel
2016-01-01
An exact and approximate kinematic analysis of a roller chain drive modeled as a four-bar mechanism is presented. The span connects the sprockets such that they rotate in the same direction, and the sprocket size, number of teeth, and shaft center distance can be arbitrary. The driven sprocket...... to be very good agreement. All together this gives new insights into the characteristics of chain drive kinematics and the influence of main design parameters....
2. Direct reactions in inverse kinematics for nuclear structure studies far off stability at low incident energies
International Nuclear Information System (INIS)
Egelhof, P.
1997-02-01
The investigation of light-ion induced direct reactions with exotic beams in inverse kinematics gives access to a wide field of nuclear structure studies in the region far off stability. The present contribution will focus on the investigation of few-nucleon transfer reactions, which turn out to be most favourably studied with good-quality low-energy radioactive beams, as provided by the new generation of radioactive beam facilities presently planned or under construction at Caen, Grenoble, Munich, and elsewhere. An overview on the physics motivation, basically concerning nuclear structure and nuclear astrophysics questions, is given. Of particular interest are the nuclear shell model in the region far off stability, the two-body residual interaction in nuclei, the structure of halo nuclei, as well as the understanding of the r-process scenario. The experimental conditions, along with the experimental concept, for such measurements are discussed with particular emphasis on the kinematical conditions, the observables, as well as the appropriate detection schemes. The concept of a large solid angle TPC ionization chamber as an active target for experiments with low-energy radioactive beams is presented. It turns out to be a highly effective detection scheme, well suited for the present experimental conditions, at least for light exotic beams up to Z∼20. (orig.)
3. pynoddy 1.0: an experimental platform for automated 3-D kinematic and potential field modelling
Science.gov (United States)
Florian Wellmann, J.; Thiele, Sam T.; Lindsay, Mark D.; Jessell, Mark W.
2016-03-01
We present a novel methodology for performing experiments with subsurface structural models using a set of flexible and extensible Python modules. We utilize the ability of kinematic modelling techniques to describe major deformational, tectonic, and magmatic events at low computational cost to develop experiments testing the interactions between multiple kinematic events, effect of uncertainty regarding event timing, and kinematic properties. These tests are simple to implement and perform, as they are automated within the Python scripting language, allowing the encapsulation of entire kinematic experiments within high-level class definitions and fully reproducible results. In addition, we provide a link to geophysical potential-field simulations to evaluate the effect of parameter uncertainties on maps of gravity and magnetics. We provide relevant fundamental information on kinematic modelling and our implementation, and showcase the application of our novel methods to investigate the interaction of multiple tectonic events on a pre-defined stratigraphy, the effect of changing kinematic parameters on simulated geophysical potential fields, and the distribution of uncertain areas in a full 3-D kinematic model, based on estimated uncertainties in kinematic input parameters. Additional possibilities for linking kinematic modelling to subsequent process simulations are discussed, as well as additional aspects of future research. Our modules are freely available on github, including documentation and tutorial examples, and we encourage the contribution to this project.
4. How wing kinematics affect power requirements and aerodynamic force production in a robotic bat wing
International Nuclear Information System (INIS)
Bahlman, Joseph W; Swartz, Sharon M; Breuer, Kenneth S
2014-01-01
Bats display a wide variety of behaviors that require different amounts of aerodynamic force. To control and modulate aerodynamic force, bats change wing kinematics, which, in turn, may change the power required for wing motion. There are many kinematic mechanisms that bats, and other flapping animals, can use to increase aerodynamic force, e.g. increasing wingbeat frequency or amplitude. However, we do not know if there is a difference in energetic cost between these different kinematic mechanisms. To assess the relationship between mechanical power input and aerodynamic force output across different isolated kinematic parameters, we programmed a robotic bat wing to flap over a range of kinematic parameters and measured aerodynamic force and mechanical power. We systematically varied five kinematic parameters: wingbeat frequency, wingbeat amplitude, stroke plane angle, downstroke ratio, and wing folding. Kinematic values were based on observed values from free flying Cynopterus brachyotis, the species on which the robot was based. We describe how lift, thrust, and power change with increases in each kinematic variable. We compare the power costs associated with generating additional force through the four kinematic mechanisms controlled at the shoulder, and show that all four mechanisms require approximately the same power to generate a given force. This result suggests that no single parameter offers an energetic advantage over the others. Finally, we show that retracting the wing during upstroke reduces power requirements for flapping and increases net lift production, but decreases net thrust production. These results compare well with studies performed on C. brachyotis, offering insight into natural flight kinematics. (paper)
5. The kinematic footprints of five stellar streams in Andromeda's halo
Science.gov (United States)
Chapman, S. C.; Ibata, R.; Irwin, M.; Koch, A.; Letarte, B.; Martin, N.; Collins, M.; Lewis, G. F.; McConnachie, A.; Peñarrubia, J.; Rich, R. M.; Trethewey, D.; Ferguson, A.; Huxor, A.; Tanvir, N.
2008-11-01
We present a spectroscopic analysis of five stellar streams (A', B', Cr', Cp' and D') as well as the extended star cluster, EC4, which lies within StreamC', all discovered in the halo of M31 from our Canada-France-Hawaii Telescope/MegaCam survey. These spectroscopic results were initially serendipitous, making use of our existing observations from the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope, and thereby emphasizing the ubiquity of tidal streams that account for ~70 per cent of the M31 halo stars in the targeted fields. Subsequent spectroscopy was then procured in StreamC' and StreamD' to trace the velocity gradient along the streams. Nine metal-rich ([Fe/H] ~ -0.7) stars at vhel = -349.5kms-1,σv,corr ~ 5.1 +/- 2.5km s-1 are proposed as a serendipitous detection of StreamCr', with follow-up kinematic identification at a further point along the stream. Seven metal-poor ([Fe/H] ~-1.3) stars confined to a narrow, 15 km s-1 velocity bin centred at vhel = -285.6, σv,corr = 4.3+1.7-1.4 km s-1 represent a kinematic detection of StreamCp', again with follow-up kinematic identification further along the stream. For the cluster EC4, candidate member stars with average [Fe/H] ~-1.4, are found at vhel = -282 suggesting it could be related to StreamCp'. No similarly obvious cold kinematic candidate is found for StreamD', although candidates are proposed in both of two spectroscopic pointings along the stream (both at ~ -400km s-1). Spectroscopy near the edge of StreamB' suggests a likely kinematic detection at vhel ~ -330, σv,corr ~ 6.9km s-1, while a candidate kinematic detection of Stream`A' is found (plausibly associated to M33 rather than M31) with vhel ~ -170, σv,corr = 12.5km s-1. The low dispersion of the streams in kinematics, physical thickness and metallicity makes it hard to reconcile with a scenario whereby these stream structures as an ensemble are related to the giant southern stream. We conclude that the M31 stellar
6. Distal hindlimb kinematics of galloping Thoroughbred racehorses on dirt and synthetic racetrack surfaces.
Science.gov (United States)
Symons, J E; Garcia, T C; Stover, S M
2014-03-01
The effect of racetrack surface (dirt or synthetic) on distal hindlimb kinematics of racehorses running at competition speeds is not known. To compare distal hindlimb and hoof kinematics during stance of breezing (unrestrained gallop) racehorses between dirt and synthetic surfaces. Two-dimensional kinematic video analysis of 5 Thoroughbred racehorses galloping at high speeds (12-17 m/s) on a dirt racetrack and a synthetic racetrack. The positions of kinematic markers applied to the left hindlimb were recorded at 500 Hz. Position, velocity and acceleration of joint angles and hoof translation during stance were calculated in the sagittal plane. Peak translational and angular kinematic values were compared between the dirt and synthetic race surfaces using mixed model analyses of covariance. Maximum and heel-strike metatarsophalangeal (fetlock) angles were greater (Pdirt surface than on the synthetic surface. Maximum fetlock angle occurred earlier during stance on the dirt surface (Pdirt surface (Pdirt surface than on a synthetic surface. Synthetic race surfaces may mitigate risk of injury to hindlimb fetlock structures by reducing fetlock hyperextension and associated strains in fetlock support structures. Differences in hoof slide may contribute to different distal hindlimb kinematics between surfaces. © 2013 EVJ Ltd.
7. Directed Neutron Beams From Inverse Kinematic Reactions
Science.gov (United States)
Vanhoy, J. R.; Guardala, N. A.; Glass, G. A.
2011-06-01
Kinematic focusing of an emitted fairly mono-energetic neutron beam by the use of inverse-kinematic reactions, i.e. where the projectile mass is greater than the target atom's mass, can provide for the utilization of a significant fraction of the fast neutron yield and also provide for a safer radiation environment. We examine the merit of various neutron production reactions and consider the practicalities of producing the primary beam using the suitable accelerator technologies. Preliminary progress at the NSWC-Carderock Positive Ion Accelerator Facility is described. Possible important applications for this type of neutron-based system can be both advanced medical imaging techniques and active "stand-off" interrogation of contraband items.
8. 6th International Workshop on Computational Kinematics
CERN Document Server
Gracia, Alba
2014-01-01
Computational kinematics is an enthralling area of science with a rich spectrum of problems at the junction of mechanics, robotics, computer science, mathematics, and computer graphics. The covered topics include design and optimization of cable-driven robots, analysis of parallel manipulators, motion planning, numerical methods for mechanism calibration and optimization, geometric approaches to mechanism analysis and design, synthesis of mechanisms, kinematical issues in biomechanics, construction of novel mechanical devices, as well as detection and treatment of singularities. The results should be of interest for practicing and research engineers as well as Ph.D. students from the fields of mechanical and electrical engineering, computer science, and computer graphics. Indexed in Conference Proceedings Citation Index- Science (CPCI-S).
9. Plasma electron hole kinematics. I. Momentum conservation
Energy Technology Data Exchange (ETDEWEB)
Hutchinson, I. H.; Zhou, C. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2016-08-15
We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, which behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.
10. Failed Radiatively Accelerated Dusty Outflow Model of the Broad Line Region in Active Galactic Nuclei. I. Analytical Solution
Energy Technology Data Exchange (ETDEWEB)
Czerny, B.; Panda, S.; Wildy, C.; Sniegowska, M. [Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Li, Yan-Rong; Wang, J.-M. [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China); Hryniewicz, K.; Sredzinska, J. [Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716 Warsaw (Poland); Karas, V., E-mail: bcz@cft.edu.pl [Astronomical Institute, Academy of Sciences, Bocni II 1401, CZ-141 00 Prague (Czech Republic)
2017-09-10
The physical origin of the broad line region in active galactic nuclei is still unclear despite many years of observational studies. The reason is that the region is unresolved, and the reverberation mapping results imply a complex velocity field. We adopt a theory-motivated approach to identify the principal mechanism responsible for this complex phenomenon. We consider the possibility that the role of dust is essential. We assume that the local radiation pressure acting on the dust in the accretion disk atmosphere launches the outflow of material, but higher above the disk the irradiation from the central parts causes dust evaporation and a subsequent fallback. This failed radiatively accelerated dusty outflow is expected to represent the material forming low ionization lines. In this paper we formulate simple analytical equations to describe the cloud motion, including the evaporation phase. The model is fully described just by the basic parameters of black hole mass, accretion rate, black hole spin, and viewing angle. We study how the spectral line generic profiles correspond to this dynamic. We show that the virial factor calculated from our model strongly depends on the black hole mass in the case of enhanced dust opacity, and thus it then correlates with the line width. This could explain why the virial factor measured in galaxies with pseudobulges differs from that obtained from objects with classical bulges, although the trend predicted by the current version of the model is opposite to the observed trend.
11. The Effect of Direction on Cursor Moving Kinematics
Directory of Open Access Journals (Sweden)
Chiu-Ping Lu
2012-02-01
Full Text Available There have been only few studies to substantiate the kinematic characteristics of cursor movement. In this study, a quantitative experimental research method was used to explore the effect of moving direction on the kinematics of cursor movement in 24 typical young persons using our previously developed computerized measuring program. The results of multiple one way repeated measures ANOVAs and post hoc LSD tests demonstrated that the moving direction had effects on average velocity, movement time, movement unit and peak velocity. Moving leftward showed better efficiency than moving rightward, upward and downward from the kinematic evidences such as velocity, movement unit and time. Moreover, the unique pattern of the power spectral density (PSD of velocity (strategy for power application explained why the smoothness was still maintained while moving leftward even under an unstable situation with larger momentum. Moreover, the information from this cursor moving study can guide us to relocate the toolbars and icons in the window interface, especially for individuals with physical disabilities whose performances are easily interrupted while controlling the cursor in specific directions.
12. Collision-free inverse kinematics of a 7 link cucumber picking robot
NARCIS (Netherlands)
Henten, van E.J.; Schenk, E.J.J.; Willigenburg, van L.G.; Meuleman, J.; Barreiro, P.
2008-01-01
The paper presents results of research on inverse kinematics algorithms to be used in a functional model of a cucumber harvesting robot consisting of a redundant manipulator with one prismatic and six rotational joints (P6R). Within a first generic approach, the inverse kinematics problem was
13. Quantum-mechanical vs. semi-classical spectral-line widths and shifts from the line core in the non-impact region for the Ar-perturbed/ K-radiator system
International Nuclear Information System (INIS)
Kreye, W.C.
2007-01-01
New quantum-mechanical (QM) and semi-classical (SC) shifts (d's) and widths (HWHM's, w's) were measured from the line core of computed full spectral-line shapes for the Ar-perturbed/K-radiator system (K/Ar). The initial state of our model was based on a 4p 2 P 3/2,1/2 pseudo-potential for the K/Ar system, and the final state on a zero potential. The Fourier transform of the line shape formed the basis for the computations. Excellent agreement was found between the QM and SC values of d and of w in a high-pressure (P) non-impact region, which was characterized by a √P dependence of w and a P dependence of d. These agreements were shown to be another example of a correspondence between classical (SC) quantities and QM quantities in the limit of large quantum numbers. Typically at P=1x10 6 Torr and T=400 K, w QM =448 cm -1 and w SC =479 cm -1 , where the deviation from the mean is ±3.3%. Also, d QM =-3815 cm -1 and d SC =-3716 cm -1 , where the deviation from the mean is ±1.3%. A new general method was formulated which yielded a definite pressure P 0 , which was defined as an upper limit to the low-pressure impact approximation and a lower limit to the non-impact region
14. Baryon chiral perturbation theory extended beyond the low-energy region.
Science.gov (United States)
Epelbaum, E; Gegelia, J; Meißner, Ulf-G; Yao, De-Liang
We consider an extension of the one-nucleon sector of baryon chiral perturbation theory beyond the low-energy region. The applicability of this approach for higher energies is restricted to small scattering angles, i.e. the kinematical region, where the quark structure of hadrons cannot be resolved. The main idea is to re-arrange the low-energy effective Lagrangian according to a new power counting and to exploit the freedom of the choice of the renormalization condition for loop diagrams. We generalize the extended on-mass-shell scheme for the one-nucleon sector of baryon chiral perturbation theory by choosing a sliding scale, that is, we expand the physical amplitudes around kinematical points beyond the threshold. This requires the introduction of complex-valued renormalized coupling constants, which can be either extracted from experimental data, or calculated using the renormalization group evolution of coupling constants fixed in threshold region.
15. Baryon chiral perturbation theory extended beyond the low-energy region
International Nuclear Information System (INIS)
Epelbaum, E.; Gegelia, J.; Meissner, Ulf G.; Yao, De-Liang
2015-01-01
We consider an extension of the one-nucleon sector of baryon chiral perturbation theory beyond the low-energy region. The applicability of this approach for higher energies is restricted to small scattering angles, i.e. the kinematical region, where the quark structure of hadrons cannot be resolved. The main idea is to re-arrange the low-energy effective Lagrangian according to a new power counting and to exploit the freedom of the choice of the renormalization condition for loop diagrams. We generalize the extended on-mass-shell scheme for the one-nucleon sector of baryon chiral perturbation theory by choosing a sliding scale, that is, we expand the physical amplitudes around kinematical points beyond the threshold. This requires the introduction of complex-valued renormalized coupling constants, which can be either extracted from experimental data, or calculated using the renormalization group evolution of coupling constants fixed in threshold region. (orig.)
16. A serial-kinematic nanopositioner for high-speed atomic force microscopy
Energy Technology Data Exchange (ETDEWEB)
Wadikhaye, Sachin P., E-mail: sachin.wadikhaye@uon.edu.au; Yong, Yuen Kuan; Reza Moheimani, S. O. [School of Electrical Engineering and Computer Science, The University of Newcastle, Callaghan, NSW (Australia)
2014-10-15
A flexure-guided serial-kinematic XYZ nanopositioner for high-speed Atomic Force Microscopy is presented in this paper. Two aspects influencing the performance of serial-kinematic nanopositioners are studied in this work. First, mass reduction by using tapered flexures is proposed to increased the natural frequency of the nanopositioner. 25% increase in the natural frequency is achieved due to reduced mass with tapered flexures. Second, a study of possible sensor positioning in a serial-kinematic nanopositioner is presented. An arrangement of sensors for exact estimation of cross-coupling is incorporated in the proposed design. A feedforward control strategy based on phaser approach is presented to mitigate the dynamics and nonlinearity in the system. Limitations in design approach and control strategy are discussed in the Conclusion.
17. A serial-kinematic nanopositioner for high-speed atomic force microscopy
International Nuclear Information System (INIS)
Wadikhaye, Sachin P.; Yong, Yuen Kuan; Reza Moheimani, S. O.
2014-01-01
A flexure-guided serial-kinematic XYZ nanopositioner for high-speed Atomic Force Microscopy is presented in this paper. Two aspects influencing the performance of serial-kinematic nanopositioners are studied in this work. First, mass reduction by using tapered flexures is proposed to increased the natural frequency of the nanopositioner. 25% increase in the natural frequency is achieved due to reduced mass with tapered flexures. Second, a study of possible sensor positioning in a serial-kinematic nanopositioner is presented. An arrangement of sensors for exact estimation of cross-coupling is incorporated in the proposed design. A feedforward control strategy based on phaser approach is presented to mitigate the dynamics and nonlinearity in the system. Limitations in design approach and control strategy are discussed in the Conclusion
18. Pure Gravities via Color-Kinematics Duality for Fundamental Matter
CERN Document Server
Johansson, Henrik
2015-01-01
We give a prescription for the computation of loop-level scattering amplitudes in pure Einstein gravity, and four-dimensional pure supergravities, using the color-kinematics duality. Amplitudes are constructed using double copies of pure (super-)Yang-Mills parts and additional contributions from double copies of fundamental matter, which are treated as ghosts. The opposite-statistics states cancel the unwanted dilaton and axion in the bosonic theory, as well as the extra matter supermultiplets in supergravities. As a spinoff, we obtain a prescription for obtaining amplitudes in supergravities with arbitrary non-self-interacting matter. As a prerequisite, we extend the color-kinematics duality from the adjoint to the fundamental representation of the gauge group. We explain the numerator relations that the fundamental kinematic Lie algebra should satisfy. We give nontrivial evidence supporting our construction using explicit tree and loop amplitudes, as well as more general arguments.
19. Detailed solution to a complex kinematics chain manipulator
International Nuclear Information System (INIS)
March-Leuba, S.; Jansen, J.F.; Kress, R.L.; Babcock, S.M.
1992-01-01
This paper presents a relatively simple method based on planar geometry to analyze the inverse kinematics for closed kinematics chain (CKC) mechanisms. Although the general problem and method of approach are well defined, the study of the inverse kinematics of a closed-chain mechanism is a very complicated one. The current methodology allows closed-form solutions to be found, if a solution exists, for the displacements and velocities of all manipulator joints. Critical design parameters can be identified and optimized by using symbolic models. This paper will focus on planar closed-chain structures extended with a rotational base. However, with open and CKC mechanisms combined in different planes, the extension to the case is straightforward. Further, real-time algorithms are developed that can be handled by existing microprocessor technology. To clarify the methodology, the Soldier Robot Interface Project (SRIP) manipulator is analyzed, and a graphic simulation is presented as a verification of the results. This manipulator has 17 links, 24 one-degree-of-freedom (DOF) joints, and 7 CKC loops working in a plane and a rotational base, which determine its 3 DOFs. The SRIP manipulator allows a decoupled linear motion along the vertical or horizontal directions using only one of its linear actuators. The symbolic solution for the inverse kinematics allows optimization to be performed to further decouple the Cartesian motions by changing link lengths of the manipulator. The conclusion achieved by the optimization is that only two link lengths need to be changed to tune the manipulator for a perfect decoupling at each area of the workspace
20. Scapular kinematics and muscle activities during pushing tasks.
Science.gov (United States)
Huang, Chun-Kai; Siu, Ka-Chun; Lien, Hen-Yu; Lee, Yun-Ju; Lin, Yang-Hua
2013-01-01
Pushing tasks are functional activities of daily living. However, shoulder complaints exist among workers exposed to regular pushing conditions. It is crucial to investigate the control of shoulder girdles during pushing tasks. The objective of the study was to demonstrate scapular muscle activities and motions on the dominant side during pushing tasks and the relationship between scapular kinematics and muscle activities in different pushing conditions. Thirty healthy adults were recruited to push a four-wheel cart in six pushing conditions. The electromyographic signals of the upper trapezius (UT) and serratus anterior (SA) muscles were recorded. A video-based system was used for measuring the movement of the shoulder girdle and scapular kinematics. Differences in scapular kinematics and muscle activities due to the effects of handle heights and weights of the cart were analyzed using two-way ANOVA with repeated measures. The relationships between scapular kinematics and muscle activities were examined by Pearson's correlation coefficients. The changes in upper trapezius and serratus anterior muscle activities increased significantly with increased pushing weights in the one-step pushing phase. The UT/SA ratio on the dominant side decreases significantly with increased handle heights in the one-step pushing phase. The changes in upward rotation, lateral slide and elevation of the scapula decreased with increased pushing loads in the trunk-forward pushing phase. This study indicated that increased pushing loads result in decreased motions of upward rotation, lateral slide and elevation of the scapula; decreased handle heights result in relatively increased activities of the serratus anterior muscles during pushing tasks.
1. The brown dwarf kinematics project
Science.gov (United States)
Faherty, Jackie K.
2010-10-01
Brown dwarfs are a recent addition to the plethora of objects studied in Astronomy. With theoretical masses between 13 and 75 MJupiter , they lack sustained stable Hydrogen burning so they never join the stellar main sequence. They have physical properties similar to both planets and low-mass stars so studies of their population inform on both. The distances and kinematics of brown dwarfs provide key statistical constraints on their ages, moving group membership, absolute brightnesses, evolutionary trends, and multiplicity. Yet, until my thesis, fundamental measurements of parallax and proper motion were made for only a relatively small fraction of the known population. To address this deficiency, I initiated the Brown Dwarf Kinematics (BDKP). Over the past four years I have re-imaged the majority of spectroscopically confirmed field brown dwarfs (or ultracool dwarfs---UCDs) and created the largest proper motion catalog for ultracool dwarfs to date. Using new astrometric information I examined population characteristics such as ages calculated from velocity dispersions and correlations between kinematics and colors. Using proper motions, I identified several new wide co-moving companions and investigated binding energy (and hence formation) limitations as well as the frequency of hierarchical companions. Concurrently over the past four years I have been conducting a parallax survey of 84 UCDs including those showing spectral signatures of youth, metal-poor brown dwarfs, and those within 20 pc of the Sun. Using absolute magnitude relations in J,H, and K, I identified overluminous binary candidates and investigated known flux-reversal binaries. Using current evolutionary models, I compared the MK vs J-K color magnitude diagram to model predictions and found that the low-surface gravity dwarfs are significantly red-ward and underluminous of predictions and a handful of late-type T dwarfs may require thicker clouds to account for their scatter.
2. CHEMICAL EVOLUTION OF THE UNIVERSE AT 0.7 < z < 1.6 DERIVED FROM ABUNDANCE DIAGNOSTICS OF THE BROAD-LINE REGION OF QUASARS
Energy Technology Data Exchange (ETDEWEB)
Sameshima, H. [Laboratory of Infrared High-resolution Spectroscopy, Koyama Astronomical Observatory, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Yoshii, Y.; Kawara, K., E-mail: sameshima@cc.kyoto-su.ac.jp [Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)
2017-01-10
We present an analysis of Mg ii λ 2798 and Fe ii UV emission lines for archival Sloan Digital Sky Survey (SDSS) quasars to explore the diagnostics of the magnesium-to-iron abundance ratio in a broad-line region cloud. Our sample consists of 17,432 quasars selected from the SDSS Data Release 7 with a redshift range of 0.72 < z < 1.63. A strong anticorrelation between the Mg ii equivalent width (EW) and the Eddington ratio is found, while only a weak positive correlation is found between the Fe ii EW and the Eddington ratio. To investigate the origin of these differing behaviors of Mg ii and Fe ii emission lines, we perform photoionization calculations using the Cloudy code, where constraints from recent reverberation mapping studies are considered. We find from calculations that (1) Mg ii and Fe ii emission lines are created at different regions in a photoionized cloud, and (2) their EW correlations with the Eddington ratio can be explained by just changing the cloud gas density. These results indicate that the Mg ii/Fe ii flux ratio, which has been used as a first-order proxy for the Mg/Fe abundance ratio in chemical evolution studies with quasar emission lines, depends largely on the cloud gas density. By correcting this density dependence, we propose new diagnostics of the Mg/Fe abundance ratio for a broad-line region cloud. In comparing the derived Mg/Fe abundance ratios with chemical evolution models, we suggest that α -enrichment by mass loss from metal-poor intermediate-mass stars occurred at z ∼ 2 or earlier.
3. The magnetic field near power lines in the Moscow region: the results of measurements and their analyze
Directory of Open Access Journals (Sweden)
Prokofyeva A.S.
2014-12-01
Full Text Available The aim: to analyze the real power frequency magnetic field (50 Hz values near power lines. The material. Long-term measurements of the power frequency magnetic field (50 Hz near power lines of 110 kV, 220 kVand 500 kVin the Moscow region. Methods. Measurements were made by tracks which were perpendicular to the wires. Length of tracks was up to 40 m. Sensor of measurer was located on 1.8 m under the ground. General quantity of measurement points were 1103. The results. Was obtained general characteristics of real values of strength of electric field and values of magnetic flux density depending to distance to the projection last wire near power lines. Conclusion. Analysis of the results has the values of the magnetic field of power lines correspond to the Russian rules in all cases. Using additional World Health Organization safety criteria for magnetic fields (the class of carcinogenic risks 2B requires the expansion of the health safety zone 2-3 times.
4. Quantifying meniscal kinematics in dogs.
Science.gov (United States)
Park, Brian H; Banks, Scott A; Pozzi, Antonio
2017-11-06
The dog has been used extensively as an experimental model to study meniscal treatments such as meniscectomy, meniscal repair, transplantation, and regeneration. However, there is very little information on meniscal kinematics in the dog. This study used MR imaging to quantify in vitro meniscal kinematics in loaded dog knees in four distinct poses: extension, flexion, internal, and external rotation. A new method was used to track the meniscal poses along the convex and p | {"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": 0.8116136789321899, "perplexity": 4016.2148597416785}, "config": {"markdown_headings": false, "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-2022-33/segments/1659882570921.9/warc/CC-MAIN-20220809094531-20220809124531-00664.warc.gz"} |
https://plus.tuni.fi/comp.cs.140/fall-2022/modules_07/07_exercises_07_sevenzipsearch/ | # ⌛⌛ Text search inside a 7z file¶
The submission consists of a Maven project. Place your answer into the file pom.xml and into Java files named as you wish in the subdirectory src. Both the pom.xml file and the src subdirectory must in turn be located in the directory Round7/sevenzipsearch. Remember to pull task material from student_template_project.
In this task you will try handling files compressed with 7z compression by using by using the Apache Commons Compress library. You will actually need the following two libraries as dependencies:
7z files (Wikipedia article) are as such similar to zip files but they use a more efficient compression algorithm.
Your task is to implement a program that searches for occurrences of a given search word in the text files contained in a given 7z file. To be more precise, the program must work as follows:
• The program takes two command line parameters: a name of the file and a search word.
• The program assumes that the first command line parameter corresponds to a 7z file. The program scans the files in the given 7z file and performs a word search in each found text file.
• A file is recognized as a text file based on its ending: the search is performed if and only if the file ending is .txt”.
• At the beginning of each search the name of the file is printed out.
• At the end of each search one extra new line is printed.
• Performing the word search:
• The file is read one line at a time and all occurrences of the search word are searched from each line, ignoring character case.
• If at least one occurrence is found, the line in question is printed out in the form “line number: line”, where line number is the number of the line in question (the first line in the file has number 1), and line is the line in question formatted in such a way that all occurrences of the search word have been changed to use upper case letters.
The example outputs clarify the format.
The automatic tests (and the ones given below) assume that you make the following definitions in your pom.xml project file:
• The value of artifactId is sevenzipsearch.
• The value of version element is 1.0.
• A onejar plugin definition where the value of mainClass element refers to the main class of your program (which you can name freely in this task).
## Testing¶
You can test your program with the test input files java.7z and Dracula.7z, and the example output files output1.txt, output2.txt and output3.txt.
When implementing the task, it might be a good idea to inspect the contents of the 7z files java.7z and Dracula.7z. Many operating systems (e.g. Ubuntu Linux) know how to open 7z files without a separate program. Otherwise you can use some compression program that supports the 7z format. A suitable choice might be 7-zip (https://www.7-zip.org/), which is installed on the university computers.
Compile your program with mvn package and run the tests as java -jar target/sevenzipsearch-1.0.one-jar.jar java.7z oracle, java -jar target/sevenzipsearch-1.0.one-jar.jar Dracula.7z under and java -jar target/sevenzipsearch-1.0.one-jar.jar Dracula.7z press. The expected outputs of these three tests are depicted in the files output1.txt, output2.txt and output3.txt.
A+ presents the exercise submission form here.
Posting submission... | {"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": 0.4649026393890381, "perplexity": 2052.2874590606734}, "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/1679296945433.92/warc/CC-MAIN-20230326044821-20230326074821-00613.warc.gz"} |
https://infoscience.epfl.ch/record/217705 | Infoscience
Journal article
Measurement of the decay B -> Dl nu(l) in fully reconstructed events and determination of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cb vertical bar
We present a determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cb vertical bar using the decay B -> Dl nu(l) (l = e,mu) based on 711 fb(-1) of e(+)e(-) -> Upsilon(4S) data recorded by the Belle detector and containing 772 x 10(6) B (B) over bar pairs. One B meson in the event is fully reconstructed in a hadronic decay mode, while the other, on the signal side, is partially reconstructed from a charged lepton and either a D+ or D-0 meson in a total of 23 hadronic decay modes. The isospin-averaged branching fraction of the decay B -> Dl nu(l) is found to be B(B-0 -> D(-)l(vertical bar)nu(l)) = (2.31 +/- 0.03(stat) +/- 0.11(syst))%. Analyzing the differential decay rate as a function of the hadronic recoil with the parametrization of Caprini, Lellouch, and Neubert and using the form-factor prediction G(1) = 1.0541 +/- 0.0083 calculated by FNAL/MILC, we obtain eta(EW)vertical bar V-cb vertical bar = (40.12 +/- 1.34) x 10(-3), where eta(EW) is the electroweak correction factor. Alternatively, assuming the model-independent form-factor parametrization of Boyd, Grinstein, and Lebed and using lattice QCD data from the FNAL/MILC and HPQCD collaborations, we find eta(EW)vertical bar V-cb vertical bar = (41.10 +/- 1.14) x 10(-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": 0.9748579859733582, "perplexity": 6933.675627155082}, "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-2016-44/segments/1476988718309.70/warc/CC-MAIN-20161020183838-00552-ip-10-171-6-4.ec2.internal.warc.gz"} |
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0007290 | Research Article
# Characterization of a Natural Mutator Variant of Human DNA Polymerase λ which Promotes Chromosomal Instability by Compromising NHEJ
• Affiliation: Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
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• Affiliation: Laboratoire d'Ingénierie des Sistèmes Biologiques et des Procédés. UMR INSA/CNRS, Toulouse, France
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• Affiliation: CNRS-IPBS (Institute of Pharmacology and Structural Biology), Toulouse, France
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• Affiliations: Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
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• Affiliation: Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
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• Affiliations: Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain, Clinical Genetics Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
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• Affiliation: Laboratory of Translational Research, Institut Català d'Oncologia-IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain
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• Affiliation: CNRS-IPBS (Institute of Pharmacology and Structural Biology), Toulouse, France
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• Affiliation: CNRS-IPBS (Institute of Pharmacology and Structural Biology), Toulouse, France
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• Affiliation: CNRS-IPBS (Institute of Pharmacology and Structural Biology), Toulouse, France
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• Affiliation: Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
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• lblanco@cbm.uam.es (LB); jseb@ipbs.fr (JSH)
Affiliation: CNRS-IPBS (Institute of Pharmacology and Structural Biology), Toulouse, France
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• lblanco@cbm.uam.es (LB); jseb@ipbs.fr (JSH)
Affiliation: Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
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• Published: October 06, 2009
• DOI: 10.1371/journal.pone.0007290
Corrections
9 Oct 2009: Terrados G, Capp J-P, Canitrot Y, García-Díaz M, Bebenek K, et al. (2009) Correction: Characterization of a Natural Mutator Variant of Human DNA Polymerase λ which Promotes Chromosomal Instability by Compromising NHEJ. PLoS ONE 4(10): 10.1371/annotation/c20f5062-ddb8-4bc2-b374-f9a901a23170. doi: 10.1371/annotation/c20f5062-ddb8-4bc2-b374-f9a901a23170 | View correction
## Abstract
### Background
DNA polymerase lambda (Polλ) is a DNA repair polymerase, which likely plays a role in base excision repair (BER) and in non-homologous end joining (NHEJ) of DNA double-strand breaks (DSB).
### Principal Findings
Here, we described a novel natural allelic variant of human Polλ (hPolλ) characterized by a single nucleotide polymorphism (SNP), C/T variation in the first base of codon 438, resulting in the amino acid change Arg to Trp. In vitro enzyme activity assays of the purified W438 Polλ variant revealed that it retained both DNA polymerization and deoxyribose phosphate (dRP) lyase activities, but had reduced base substitution fidelity. Ectopic expression of the W438 hPolλ variant in mammalian cells increases mutation frequency, affects the DSB repair NHEJ pathway, and generates chromosome aberrations. All these phenotypes are dependent upon the catalytic activity of the W438 hPolλ.
### Conclusions
The expression of a cancer-related natural variant of one specialized DNA polymerase can be associated to generic instability at the cromosomal level, probably due a defective NHEJ. These results establish that chromosomal aberrations can result from mutations in specialized DNA repair polymerases.
### Introduction
The maintenance of genome integrity is dependent on numerous mechanisms, which notably allow fidelity of DNA replication and repair of damaged DNA [1]. Those processes require a large number of proteins including DNA polymerases. Nevertheless, the recent discovery that eukaryotic cells contain many more DNA polymerases than previously thought added further complexity to our appreciation of DNA transactions (review in [2]). Function of those recently discovered DNA polymerases remain still uncertain but numerous connections between their regulation, organisation, and coordinated action for DNA protection have been already made [3]. A novel family X DNA polymerase, named Polλ, has been independently identified in three different laboratories [4][6]. Polλ forms a Polβ-like core that consists of two domains: 31 kDa polymerization domain (bearing the three conserved subdomains: fingers, palm, thumb) and 8 kDa domain [7]. In agreement with their structural relationships (32% amino acid identity), the biochemical properties of Polλ are partly similar to those of Polβ, and suggest a role in DNA repair [8]. Indeed, as Polβ, Polλ has a dRP lyase activity [9], and accordingly, these enzymes both have a role in BER [10][13]. However, unlike Polβ, Polλ contains a BRCA1 C-terminal (BRCT) domain [4], [14], [15], required for a stable interaction with NHEJ factors [16][18]. Moreover, Polλ is able to perform alignment-based gap filling for NHEJ in human nuclear extracts [19], and the expression in mammalian cells of a catalytically inactive form of Polλ decreases the frequency of NHEJ events in response to I-Sce-I –induced DSB [20]. All these features support a potential role for Polλ in the NHEJ repair of DSB.
A number of polymorphic variants have been described in several DNA repair genes that could -when adequately combined- substantially alter overall DNA repair capacity. Conversely, few reports exist on the identification and characterization of polymorphic or altered isoforms of the known DNA polymerases, with the exception of Polβ [21][24]. Here, we report the identification of a natural allelic variant of hPolλ that has reduced base substitution fidelity in vitro and whose expression in cultured cells increases mutation frequency and compromises the DSB repair pathway NHEJ, resulting in radiosensitivity and chromosomal instability.
### Results
#### Identification of a SNP in the coding region of hPolλ
Several normal and tumoral cDNA samples were screened for possible nucleotide changes in the hPolλ gene. The complete coding region of hPolλ, comprising exons 1 to 9, was amplified by polymerase chain reaction (PCR) in five overlapping fragments, named a–e (Fig. 1A), and subjected to single-stranded conformational polymorphism (SSCP) analysis. Figure 1B illustrates a representative analysis using non-paired normal and tumor ovarian tissues. As shown, fragments a, b, c and d, covering the first seven exons of hPolλ, did not produce any band with altered mobility when normal and tumoral samples were compared. Moreover, no mobility alteration was detected for fragments a–d in any other tissues analyzed. However, PCR-SCCP analysis of fragment e (covering exon 8 and the first half of exon 9 of the transcript) identified an abnormal mobility pattern when comparing normal ovary vs ovarian carcinoma GI-101 (Fig. 1B). The same variation in the PCR-SSCP profile for fragment e was identified using other tissues from the normal and tumoral panel.
Sequence analysis of the PCR fragment e, revealed the existence of a SNP, C to T variation in nucleotide position 1311 (exon 8) of the coding region of hPolλ, resulting in a single arginine (R) to tryptophan (W) amino acid substitution in codon 438 (Fig. 1C). SNP reported here has been designated rs3730477 (http://www.ncbi.nlm.nih.gov/SNP/snp_ref.cgi?rs=3730477), and is one of the two SNPs altering the coding sequence identified to date in hPolλ.
#### hPolλ W438 variant has normal polymerase and dRP lyase activities
Polλ has been proposed to be a suitable candidate to participate in BER [12], [13], as it contains both gap-filling DNA synthesis and dRP lyase activities [8], [9]. To address if the W438 mutation affects any of these activities, the wild-type form (R438) and the W438 allelic variant were overexpressed in E. coli cells and purified in parallel to compare their biochemical properties. Both enzymes showed a similar DNA polymerization capacity, and a similar affinity for dNTPs (Fig. 2A). Furthermore, both hPolλ forms were capable to excise a dRP residue, generated by the 5′ cleavage of an AP site by human apurinic/apyrimidinic endonuclease (hAPE) (Fig. 2B,C). The combination of polymerization and dRP lyase activities present in the W438 variant allows to complete BER in vitro as efficiently as in the case of the R438 wild-type hPolλ form (Fig. 2D). Moreover, there was no diference between the two isoforms in the capacity to insert either dCTP or dATP in front of a 8-oxoG lesion, or in its further extension (Figure S1). Therefore, we can conclude that substitution of arginine 438 to tryptophane in hPolλ, as it occurs in the natural W438 variant, does not significantly affect its in vitro catalytic efficiency.
#### hPolλ W438 has a lower fidelity than hPolλ R438
A major property of DNA-dependent DNA polymerases is their DNA synthesis fidelity. It has been shown that a decrease in the fidelity of a particular DNA polymerase can lead to detrimental cellular effects, including cell death, cancer, and other genetic diseases [25], [26]. Moreover, several examples exist of point mutations in Polβ causing a dramatic decrease in fidelity [27][32]. To determine whether the tryptophan substitution at position 438 affects hPolλ fidelity, we measured base substitution and insertion-deletion error rates by the wild-type (R438) and the W438 hPolλ during a short gap filling reactions in M13mp2 reversion assays [27], [28]. Base substitution errors that revert a TGA codon encoding a faint blue plaque phenotype are scored as dark blue revertants. The DNA products yielded mutant frequencies of 9.0±4.4×10−4 (hPolλ R438) and 31±12×10−4 (hPolλ W438), as an average of four independent determinations (p = 0.0007). Sequence analysis of DNA amplified from blue-plaque revertants allows error rates to be calculated for each hPolλ form. The results (Table 1) indicate that, in comparison to the wild-type, the W438 variant is less accurate for T to C and G to T substitutions by factors of 4-fold (p = 0.001) and 8-fold (p<0.022), respectively. In contrast, the insertion-deletion mutant frequencies of the two forms were similar (data not shown) when examined using a 6-nucleotide gap-filling substrate containing a template TTTT run in the +1 reading frame.
We next investigated whether overexpression of the hPolλ W438 variant could affect mutation frequency in vivo. Thus, an eukaryotic expression vector harbouring the W438 variant or the R438 wild-type form of hPolλ was transfected into Chinese hamster ovary (CHO) cells to obtain isogenic strains expressing each isoform (R1 and R2, for R438; W1 and W2, for the W438 variant). Immunoblotting of cellular extracts using murine Polλ polyclonal antibodies [4] confirmed similar hPolλ levels in all overexpressing cell lines (Fig. 3A). The poor detection of the endogenous hamster Polλ in the control strains Dra10 and CT (transfected with the empty vector) precluded a proper quantification of the absolute ectopic expression levels. We next measured the frequency of spontaneous mutations by the conventional hypoxanthine phosphoribosyl transferase (HPRT) methodology that tests the appearance of a mutational event leading to 6-thioguanine resistance (6-TGR) [33]. Figure 3B shows that the mutation frequency corresponding to clones R1 and R2 was 2- to 3- fold higher than in control cell lines (clones DRA10 and CT). This agrees with previous data showing that Polβ overproduction increases (up to 4-fold) mutagenesis using the same assay [33]. More interestingly, overexpression of the W438 variant (clones W1 and W2) produced up to an 8-fold increase in the in vivo mutation frequency (Fig. 3B). Importantly, expression of a polymerization-deficient W438 variant (clone WD; see also Materials and Methods) did not produce such a mutation increase (Fig. 3B). Overall, these results show that cells expressing the W438 variant form of hPolλ, shown to be error-prone in vitro, acquire increased mutability.
#### 3D-structure of the W438 hPolλ variant
The structure of hPolλ in complex with DNA and an incoming dNTP has recently been reported [34]. This structure indicates that R438 is a surface residue located in a loop of the palm subdomain (Figure S2). The B-factors in this loop are high, suggesting a certain degree of disorder and, in fact, the density for R438 was not sufficient to build the entire side chain. To try to understand the effects of the R438W substitution we crystallized the 39 kDa domain of the W438 variant under the same conditions already reported for the R438. We were able to obtain crystals that diffracted to low (2.8 Å) resolution. The density was of sufficient quality to assess that the overall fold of the W438 variant is identical to that of the R438 wild-type form, indicating that the R438W substitution does not result in a major conformational alteration (the rmsd between the R and W structures is 0.509 for 324 C-a atoms). However, the loop containing residue 438 had a high degree of disorder and no density was observed for the W438 side chain (not shown), suggesting that the R438W substitution might result in local structural alterations. It can be speculated that such a flexibility could be relatable to a necessary conformational change of this loop (that could be altered by the W438 polymorphism), required to form the enzyme:DNA:dNTP ternary complex and thus having an impact on polymerization fidelity. Interestingly, this loop is located next to the N-terminal end of α-helix M in hPolλ, and it is known that a mutation in this α-helix in Polβ can severely affect enzyme fidelity [35]. Amino acid sequence comparison of DNA polymerases lambda from different species indicates that an arginine residue is not highly conserved, being substituted for some other amino acid residues as, lysine, glutamine, and even alanine. As a tryptophane is not included among the wild-type options, we would favour that the observed effects are probably due to that particular bulky aromatic amino acid (tryptophane) substitution of the human Polλ W438 variant.
#### Expression of the W438 hPolλ variant reduces cellular NHEJ activity
Considering the proposed role of Polλ in DSB repair, we examined survival after ionizing radiation (IR) exposure of the different hamster cell lines described above (Fig. 3), expressing comparable levels of either R438 or W438 forms of hPolλ. Expression of the W438 variant conferred a significantly higher sensitivity to IR relative to control or R438 expressing cells (Fig. 4A). Identical results were obtained in transfected human MRC5 fibroblasts (Figure S3, partA). Interestingly, this HPRT hypersensitivity, induced by the presence of the W438 form, was not observed in a NHEJ-defective cell line (XRCC4KDcells) (Figure S3, partB), suggesting that the presence of the W438 hPolλ variant may result in a defective NHEJ. We therefore evaluated the effect of both hPolλ isoforms directly on the cellular NHEJ activity. Cellular models (C′10 and A′7 cell lines) with stably integrated NHEJ substrates [20, 36; Fig. 4B] were transfected by each isoform (R438 and W438 variant) to obtain cellular clones (C′R, C′W, A′R, A′W), expressing similar levels as confirmed by immunoblotting (Fig. 4C). The fragment generated after I-Sce-I transfection allows to measure deletion and inversion events. In the first cell line (C′10) the two I-Sce-I sites are in direct orientation resulting in CD4 expression after deletion events (the most frequent events) or CD8 expression after invertion events. Expression of the WT form of hPolλ (R438) did not affect the generation of deletion (CD4) and inversion (CD8) events relative to control cells as previously reported [20]. In contrast, expression of the W438 form (C′W clone) decreased by 2.5-fold the CD8 events (inversion) and by 3-fold the frequency of CD4 events (deletion) relative to control cells (Fig. 4D-left panel). This was confirmed by the use of an additional cell line (A′7) in which the two I-Sce-I sites are in inverted orientation (Fig. 4B) resulting in CD4 expression after deletion events (still the most frequent events) and CD8 expression after inversion events. Again, while no effect was shown with the WT form as previously observed [20], cells expressing the R438W variant (A′W) produced a significant decrease in the generation of deletion events (CD4) and inversion events (CD8) (4- and 3-fold decrease respectively relative to control cells) (Fig. 4D-right panel). These data demonstrate that expression of the W438 polymorphic variant of hPolλ decreases the cellular NHEJ activity, probably interfering with the maturation of both non-complementary and, at a lesser extend, complementary DNA ends during the repair of DSB generated by I-Sce-1.
#### Expression of the W438 hPolλ variant leads to chromosomal aberrations
Since defects in the NHEJ pathway are known to lead to accumulation of chromosomal aberrations either spontaneously or after IR treatment [37], [38], we performed karyotypic analyses of the different cell lines described above. Examination of metaphase spreads showed a much higher generation of spontaneous or IR-induced chromosomal aberrations in cells expressing the W438 polymorphic variant of hPolλ relative to control cells or cells expressing the R438 hPolλ (Fig. 5). Dicentric and end-to-end chromatid fusion, hallmarks of a defective NHEJ, were the most common abnormalities seen in the W438 hPolλ expressing cells. We also found rings, triradial structures, and chromatid breaks (examples of some of these aberrations are given in Fig. 5). The level of spontaneous or IR-induced aneuploidy was also significantly enhanced in the W438 hPolλ expressing cells relative to control cells or cells expressing WT (R438) hPolλ. After IR, the effect is dramatic as aneuploidy reached 85% in the case of cells expressing the W438 variant (Fig. 5). Overall, these results show that expression of the W438 hPolλ induces major chromosomal instabilities, spontaneously or after IR treatment.
#### Requirement of a functional DNA polymerase activity for the W438-associated phenotypes
A cDNA coding for a catalytically inactive form of hPolλ, in which two catalytic aspartates (D427 and D429) were changed to Ala, was obtained by site-directed mutagenesis on the pRSETB plasmid carrying the cDNA sequence of the variant W438 hPolλ gene. This construct was used to overproduce the inactive (dead) variant W438 (WD) in E. coli, that was purified as previously described [8]. As expected, DNA polymerization activity in the mutant form (WD) of the hPolλ W438 was negligible (Fig. 6A). The corresponding cDNA was transferred to the pIRES vector, and transfected into DRA10 cells, as described in Materials and Methods, to obtain the “dead” mutant clone WD. As shown in Figure 6, all the phenotypes associated with expression of the W438 variant were abolished when the inactive WD mutant was expressed. Thus, mutant WD displayed a normal NHEJ activity (Fig. 6B), a normal sensitivity to IR (Fig. 6C), and a normal karyotype analysis (Fig. 6D).
That indicates that the observed phenotyes intrinsically depend on the polymerization capacity of the variant DNA polymerase, but not indirectly due to any DNA repair disbalance produced by eventual titration (via protein:protein interactions) of NHEJ factors by the overproduced polymerase. Therefore, it must be assumed that the more frequent errors made by the polymerase variant are the direct responsible for the observed phenotypes.
### Discussion
We describe here a coding SNP in exon 8 of the POLL gene resulting in an amino acid substitution at position 438, coding for a tryptophan (W) instead of an arginine (R). This polymorphism did not affect dramatically the protein structure at the polymerization active site and consistent with this observation, in vitro assays using purified hPolλ forms R438 and W438 did not show significant differences neither in polymerase and dRP lyase activities, nor in reconstituted BER reactions. However, we found that purified W438 hPolλ displays higher error rate in vitro, and that its expression in mammalian cells severely affects maintenance of the genome stability by enhancing mutation frequency, by compromising NHEJ, and by generating spontaneous or IR-induced chromosomal aberrations. We also prove that the observed defects are directly linked to the activity of the polymerase ruling out the hypothesis of any effect of imbalance in protein/protein interactions. How does the reduced fidelity of the W438 variant could affect NHEJ and chromosome instability? Whereas the overall effects observed on NHEJ efficiency and chromosomal instability are very dramatic, it is not obvious that they might be simply due to the observed/quantified effect (3-8 fold) on nucleotide insertion fidelity. However, it is important to emphasize that although the fidelity measurements are given as a mean value, figures can be higher when considering particular mismatches, and they can be even much higher when considering mismatches made in a particular sequence context (hot spots). On the other hand, reduced polymerization accuracy may have a more drastic effect during NHEJ, as the errors introduced during such unstable gap-filling synthesis could hinder ligation, the final step of the repair pathway. Alternatively, we cannot rule out the possibility that the W438 mutation affects the direct interaction of this variant Pol lambda with some other NHEJ factors.
Interestingly, restriction fragment length polymorphism (RFLP) analysis of a collection of above 300 cases-control indicated that the W438 variant is associated to rectal cancer, and the allelic frequency of the W438 allele is 0.27 in the caucasian population (manuscript in preparation). The findings shown here demonstrate that overexpression of a cancer-related natural variant of one specialized DNA polymerase can be associated to genetic instability at the chromosomal level, probably due to a defective NHEJ. There is evidence that overexpression of Pol lambda, as well as Pol beta, occurs frequently in human tumors [39]. Analysis of the heterozygote population R/W in colorectal cancer patients shows that both alleles are expressed at the same level (our unpublished data). Therefore, expression of the W438 allele does not likely affect the global DSB repair capacity in these heterozygots in a normal physiological situation, but may predispose the cells, perhaps due to DNA repair fidelity issues, to accumulate chromosomal aberrations when excessive DSBs are generated, as it occurs in pre-cancerous hyperplasia tissues [40], or when an additional factor involved in DSB repair is altered.
In spite of their key role in DNA repair, polymorphic forms of DNA repair polymerases have been poorly described, except in several studies carried out with Polι and Polβ, where a significant number of genetic alterations were reported [35], [21][23], [41], [42]. More recently, an association between the presence of altered forms of Polβ and their overall DNA repair capacity, resulting in cellular transformation, has been described [24], [32]. Identification of which mutations in human genes are determining the genetic basis of diseases is a challenge. In this sense, the vast data generated during the human genome project only provide a minimal help to establish the relationship between sequence variation and susceptibility to disease. In addition to polymorphisms that are simply associated to causative mutations, those responsible for functional differences that directly contribute to disease are of greater importance. Loss of proofreading by a replicative polymerase as Polδ increases spontaneous tumour development in mice [43]. Is the human Polλ mutation W438 actually causative or contributory to oncogenesis? Although we do have shown an association of this mutation with rectal cancer (manuscript in preparation), it is unlikely that this sole mutation is causative to oncogenesis, but it could contribute to enhance genetic instability, one of the major hallmark in cancer cells. As proposed by Hanahan and Weinberg [44], a variant DNA repair enzyme, as that described here, might accelerate carcinogenesis by increasing genetic instability, at the nucleotide as well as at the chromosomal levels, which in turn confers a selective growth advantage during cancer-cell evolution.
### Materials and Methods
#### PCR-SSCP, cloning and sequencing
A panel of cDNAs from normal and tumoral human tissues (Clontech) was used as a template to search for possible genetic alterations in the hPolλ gene. The set of overlapping primers selected was used to cover the entire coding sequence of the gene. The sequences of primers used were: hPolλex1s:5′TAGCTTGGCCAGTAGTCGACC; hPolλex3as:5′GAAGGGAGCTCAGCCACTC; hPolλex2s:5′ATACTTCAATGGATCCCAGGG; hPolλex4as:5′TTGGGTGTTTGGTGCCTC; hPolλex4s:5′GAGGCACCAAACACCCAA; hPolλex5as:5′TCCACTTGTCTCCCTGAACAC; hPolλex5s:5′TCCATAAGCCTGTCACCTCG; hPolλex7as: 5′ GGGCATACGTTCCAGGAAG. cDNA templates were 5-fold diluted and the resulting aliquot was used as 5x stock for PCR. All PCR reactions (10 µl) were conducted using 1 µM of each primer, 0.25 mM dNTPs, 1x Taq buffer (10 mM Tris pH 8.5, 50 mM NaCl, 1,5 mM MgCl2, gelatin, 0.2 mg/ml bovine serum albumin (BSA)) and 0.25 U of Taq polymerase. Cycle parameters were as follows: 94°C, 15 s; 62°C, 30 s; 72°C, 15 s; 35 cycles. PCR products were then subjected to SSCP analysis carried out as described [45], [46]. Fragments exhibiting altered mobility patterns were cloned into the TA cloning vector pCRII (Invitrogen) and sequenced on an ABI 373 (Applied Biosystems) automatic sequencer.
#### Enzymes, DNA substrates and nucleotides
Synthetic oligonucleotides purified by polyacrylamide gel electrophoresis (PAGE) were obtained from Life Technologies. Ultrapure deoxynucleoside triphosphates, activated calf thymus DNA, [γ-32P]ATP, [α-32P]dATP, [α-32P]dCTP and [α-32P]ddATP (3000 Ci/mmol) were from Amersham Pharmacia Biotech. Terminal deoxynucleotidiltransferase (TdT) was from Promega. Human recombinant Polλ (R438 and W438 forms) were overexpressed in E. coli and purified as described [8]. Human uracil DNA glycosilase (hUDG) and hAPE were generous gifts of Dr. Samuel H. Wilson (NIEHS, NC). T4 polynucleotide kinase (PNK) was from New England Biolabs.
#### DNA polymerization assays
Reactions on activated DNA were carried out as described in [8] and were initiated by adding either the indicated or a fixed amount (60 ng; 35 nM) of each hPolλ variant, in the presence of different concentrations of the indicated dNTPs. Polymerization activity, determined as total dNMP incorporated, was calculated from the amount of radioactivity present in the excluded volume, determined by counting Cerenkov radiation. Primer extension assays were performed as described in [47] with 100 nM of either hPolλ R or hPolλ W and the indicated concentration of dNTP and incubated at 37°C for 20 min.
#### dRPlyase activity and in vitro reconstitution of BER
Reactions were performed as previously described [9]. The reaction was initiated by adding different amounts of R438 or W438 forms and incubated for 20 min at 37°C.
#### Fidelity assays
The base substitution reversion assay was performed as described [27]. Gap-filling reaction mixtures (20 µl) contained 50 mM Tris-HCl, pH 7.5, 10 mM MgCl2, 1 mM dithiothreitol, 2 µg of BSA, 4% glycerol, 1.6 nM gapped DNA, 500 µM each of dATP, dGTP, dCTP, and dTTP, 400 units of T4 DNA ligase, and 100 nM hPolλ (either R438 or W438 forms). After 1 h incubation at 37°C, the products were separated on an agarose gel, and the covalently closed circular DNA products were electroeluted from gel slices. DNA products were introduced into E. coli by electroporation and followed by plating as described [48].
#### Generation of hPolλ overexpressing cells
hPolλ expressing plasmids pIRES-hPolλ R438 and pIRES-hPolλ W438 were constructed by PCR amplification from a pRSETB plasmid carrying the cDNA sequences of either the wild-type hPolλ gene (R438 form) or the variant W438 hPolλ gene, respectively, and cloning into pIRES vector (Clontech). The construction of a catalyticaly inactive mutant of W438 (WD) was carried out as described [20]. Upon transfection in CHO-DRA10, XR-1 (XRCC4 mutant cells), and MRC5 cell lines, different clones (DRA10-R1; DRA10-R2; DRA10-W1; DRA10-W2; MRC5-R; MRC5-W; XR-1-W1; XR-1-W2) were obtained. Expression of the different hPolλ protein variants was measured by immunoblotting of total cellular extracts (75 µg) with Polλ polyclonal antibodies [4] and the actin antibodies AC-40 (Sigma-Aldrich Chemical Co).
#### Mutagenesis assay in mammalian cells
For determination of spontaneous mutagenesis, replica cultures of cells were plated at the density of 5×105 cells by plate (5 plates per experiment) and exposed to 20 µM of 6-thioguanine (6-TG) containing media in order to determine the number of HPRT mutants that are resistant to 6-TG treatment. After 8 days, plates were stained and macroscopic colonies of more than 50 cells were scored and mutation frequencies were calculated by correcting for plating efficiency.
#### Cytotoxicity studies
Cytotoxicity of ionizing radiation was determined by clonogenic assay [20]. Survival was expressed as the plating efficiency of treated cells relative to the untreated control cells. Results are the mean+/−SD of 3 independent experiments.
#### Measurement of cellular NHEJ activity
NHEJ activity was measured as described in [20]. The C′10 and A′7 cell lines were cultured in DMEM medium (GIBCO BRL, France) as previously described [34]. The C′W and A′7W clones, and the C′WD and A′7WD clones were obtained after transfection with the pIRESpuro2 vector (Clontech) containing the cDNA coding for the W438 hPolλ (W) or the inactive form of the W438 hPolλ (WD), respectively. Individual clones were obtained after transfection with jetPEI (Qbiogen, Illkirch, France) and selection with puromycin (5 µg/mL).
#### Karyotype analyses
Cells were unirradiated or irradiated at 2 Gy as described previously. Karyotype analyses were performed as described in [49]. Chromosomal distributions and aberration percentages included the analysis of at least 100 metaphases spreads for each experiment.
### Supporting Information
Figure S1.
TLS of 8oxoG lesions by hPolλ variants R438 and W438.The scheme shows the sequence of the DNA used to analyze nucleotide insertion reactions opposite dG or 8oxoG (A) or extension of primers paired to 8oxoG (B). Reactions were carried out as described under Materials and Methods, with 100 nM of either R438 or W438 isoforms of hPolλ, and using 1 µM of each indicated dNTP (A) or the indicated concentrations of dG (B). Extension of the 5′ end labeled primer (*) was examined by PAGE.
doi:10.1371/journal.pone.0007290.s001
(4.91 MB EPS)
Figure S2.
Location of the R438 residue in the crystal structure of hPolλ. Ribbon representation of the ternary pre-catalytic complex of hPolλ (PDBid 1XSN). Arg438 (magenta; pointed with an arrow) is located in a loop (shown in green) in the palm subdomain. This loop is next to the N-terminal end of α-helix M. Both α-helices M and N (shown in dark gray) are critical to position the substrates and assemble the nascent base pair binding pocket. The DNA duplex is shown in light blue. The templating base is yellow and the incoming ddTTP is red.
doi:10.1371/journal.pone.0007290.s002
(5.26 MB EPS)
Figure S3.
Cell survival after ionizing radiation. Cell survival after ionizing radiation for MRC5 control cells (MRC5), or expressing the R438 (MRC5-R) or W438 (MRC5-W) forms of hPolλ (A), and for NHEJ-defective cells (XRCC4-defficient), control (XR-1), complemented by XRCC4 (X4-V; 20), or expressing the W438 (XR-1-W1; XR-1-W2) form of hPolλ (B).
doi:10.1371/journal.pone.0007290.s003
(4.79 MB EPS)
### Author Contributions
Conceived and designed the experiments: TK JSH LB. Performed the experiments: GT JPC YC MGD KB TK FB VB. Wrote the paper: JSH LB. Supervised research: KB AV CC TK JSH.
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42. 42. Wang L, Patel U, Ghosh L, Banerjee S (1992) DNA polymerase beta mutations in human colorectal cancer. Cancer Res 52: 4824–4827.
43. 43. Goldsby R, Lawrence N, Hays L, Olmsted E, Chen X, et al. (2001) Defective DNA polymerase-delta proofreading causes cancer susceptibility in mice. Nat Med 7: 638–639.
44. 44. Hanahan D, Weinberg RA (2000) The hallmarks of cancer. Cell 100: 57–70.
45. 45. Tomka M, Kirchhoff T, Kulcsar L, Stevurkova V, Zajac V (1998) The combination of heteroduplex analysis and protein truncation test for exact detection of the APC gene mutations. Neoplasma 45: 345–348.
46. 46. Kirchhoff T, Kulcsar L, Tomka M, Stevurkova V, Zajac V (1999) Characterization of APC exon 15 germ-line mutation in FAP family with severe phenotype showing extracolonic symptoms. Neoplasma 46: 290–294.
47. 47. Picher AJ, Blanco L (2007) Human DNA polymerase lambda is a proficient extender of primer ends paired to 7,8-dihydro-8-oxoguanine. DNA Repair (Amst) 6: 1749–1756.
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Ambra 2.10.7 Managed Colocation provided
by Internet Systems Consortium. | {"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": 0.8025398254394531, "perplexity": 21882.05016236256}, "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/1413507444829.13/warc/CC-MAIN-20141017005724-00255-ip-10-16-133-185.ec2.internal.warc.gz"} |
http://weblib.cern.ch/collection/Future%20Circular%20Collider%20Documents?ln=en | # Future Circular Collider Documents
2018-05-22
16:30
Social Cost Benefit Analysis of HL-LHC / Bastianin, Andrea (Università degli Studi e INFN Milano (IT)) ; Florio, Massimo (Università degli Studi e INFN Milano (IT)) We present a Social Cost–Benefit Analysis (CBA) of the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), assessing its economic costs and benefits up to 2038. The Net Present Value (NPV) of the HL-LHC project is positive at the end of the observation period. [...] CERN-ACC-2018-0014.- Geneva : CERN, 2018 Fulltext: FCC-1805221620-ABA_OverviewCBA_HLLHCandFCC - XLSX; FCC-1805221620-ABA_OverviewCBA_HLLHCandFCC_2 - XLSX; CERN-ACC-2018-0014 - PDF;
2018-05-09
14:50
Considerations on operation schedule and maintenance aspects of FCC-hh / Niemi, Arto (CERN) ; Apollonio, Andrea (CERN) ; Foraz, Katy (CERN) The Future Circular Hadron Collider (FCC-hh) has ambitious goals for integrated luminosity production. Reaching these goals requires reducing the time for planned technical stops and commissioning, compared to the LHC. [...] CERN-ACC-2018-0013.- Geneva : CERN, 2018 Fulltext: PDF;
2018-04-03
11:54
FUTURE CIRCULAR COLLIDER LOGISTICS STUDY / Beißert, Ulrike (IML) ; Horstmann, Konstantin (IML) ; Kuhlmann, Gerd (IML) ; Nettsträter, Andreas (IML) ; Prasse, Christian (IML) ; Wohlfahrt, Andreas (IML) The Large Hadron Collider (LHC) at the European Organization for Nuclear Research CERN in Geneva is the largest and most powerful collider in the world. CERN and its research and experimental infrastructure is not only a focus for the science community but is also very much in the public eye [...] CERN-ACC-2018-0012.- Geneva : CERN, 2018 Access to fulltext document: DOCX;
2018-02-27
17:02
GPU-Powered Modelling of Nonlinear Effects due to Head-On Beam-Beam Interactions in High-Energy Hadron Colliders. / Furuseth, Sondre (EPFL - Ecole Polytechnique Federale Lausanne (CH)) The performance of high-energy circular hadron colliders, as the Large Hadron Collider, is limited by beam-beam interactions. The strongly nonlinear force between the two opposing beams causes diverging Hamiltonians and resonances, which can lead to a reduction of the lifetime of the beams. [...] CERN-ACC-2018-0008.- Geneva : CERN, 2017 Fulltext: PDF;
2018-01-30
16:57
An Open Modelling Approach for Availability and Reliability of Systems - OpenMARS / Penttinen, Jussi-Pekka ; Niemi, Arto (Tampere University of Technology (FI)) ; Gutleber, Johannes (CERN) This document introduces and gives specification for OpenMARS, which is an open modelling approach for availability and reliability of systems. It supports the most common risk assessment and operation modelling techniques. [...] CERN-ACC-2018-0006.- Geneva : CERN, 2018 Access to fulltext document: PDF;
2018-01-29
15:33
HOM power in FCC-ee cavities / Karpov, Ivan (CERN) ; Calaga, Rama (CERN) ; Chapochnikova, Elena (CERN) This Note summarizes the results of the power loss calculations for FCC-ee machines with 400.79 MHz cavity options. The requirements for the single-cell cavity design and for the operation with beam are obtained from the results for the high-current FCC-ee machine (Z). [...] CERN-ACC-2018-0005.- Geneva : CERN, 2018 Fulltext: PDF;
2017-09-05
18:45
Status of FCC-ee / FCC-hh: a story of synergy and complementarity / Blondel, Alain (Universite de Geneve (CH)) Presentation given during a lepton-photon conference CERN-ACC-SLIDES-2017-0009.- Geneva : CERN, 2017 Fulltext: PDF;
2017-08-29
16:16
Crystal collimator systems for high energy frontier / Sytov, Alexei (Universita di Ferrara & INFN (IT)) ; Tikhomirov, Viktor (Byelorussian State University (BY)) ; Lobko, Alexander (Byelorussian State University (BY)) Crystalline collimators can potentially considerably improve the cleaning performance of the presently used collimator systems using amorphous collimators. A crystal-based collimation scheme which relies on the channeling particle deflection in bent crystals has been proposed and extensively studied both theoretically and experimentally. [...] CERN-ACC-2017-0084.- Geneva : CERN, 2017 - 11 p. - Published in : Phys. Rev. Accel. Beams 20 (2017) 071001 Fulltext: PDF; In : 2nd Annual Meeting of the Future Circular Collider study 2016, Rome, Italy, 11 - 15 Apr 2016
2017-08-29
16:08
Magnetic refrigeration down to 1.6 K for the future circular collider e$^+$e$^-$ / Tkaczuk, Jakub (CEA (FR)) ; Millet, Francois ; Rousset, Bernard (CEA (FR)) ; Duval, Jean Marc (CEA (FR)) High-field superconducting rf cavities of the future circular collider e+e− may require a kW-range superfluid helium refrigeration down to 1.6 K. Magnetic refrigeration operating below 4.2 K can be an alternative to the compression/expansion helium refrigeration. [...] CERN-ACC-2017-0082.- Geneva : CERN, 2017 - Published in : Phys. Rev. Accel. Beams 20 (2017) 041001 Fulltext: PDF; In : 2nd Annual Meeting of the Future Circular Collider study 2016, Rome, Italy, 11 - 15 Apr 2016
2017-08-29
15:42
Impact of process parameters and design options on heat leaks of straight cryogenic distribution lines / Duda, Pawel (Wroclaw University of Technology (PL)) ; Chorowski, Maciej Pawel ; Polinski, J (Wroclaw University of Technology (PL)) The Future Circular Collider (FCC) accelerator will require a helium distribution system that will exceed the presently exploited transfer lines by almost 1 order of magnitude. The helium transfer line will contain five process pipes protected against heat leaks by a common thermal shield. [...] CERN-ACC-2017-0081.- Geneva : CERN, 2017 - Published in : Phys. Rev. Accel. Beams 30 (2017) 033202 Fulltext: PDF; In : 2nd Annual Meeting of the Future Circular Collider study 2016, Rome, Italy, 11 - 15 Apr 2016
Focus on:
[restricted] | {"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": 0.6622580289840698, "perplexity": 17379.00121220059}, "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-2018-22/segments/1526794865450.42/warc/CC-MAIN-20180523043959-20180523063959-00509.warc.gz"} |
http://cms.math.ca/10.4153/CJM-2012-047-x | location: Publications → journals → CJM
Abstract view
# From Quantum Groups to Groups
Published:2013-02-06
Printed: Oct 2013
In this paper we use the recent developments in the representation theory of locally compact quantum groups, to assign, to each locally compact quantum group $\mathbb{G}$, a locally compact group $\tilde {\mathbb{G}}$ which is the quantum version of point-masses, and is an invariant for the latter. We show that quantum point-masses" can be identified with several other locally compact groups that can be naturally assigned to the quantum group $\mathbb{G}$. This assignment preserves compactness as well as discreteness (hence also finiteness), and for large classes of quantum groups, amenability. We calculate this invariant for some of the most well-known examples of non-classical quantum groups. Also, we show that several structural properties of $\mathbb{G}$ are encoded by $\tilde {\mathbb{G}}$: the latter, despite being a simpler object, can carry very important information about $\mathbb{G}$.
MSC Classifications: 46L89 - Other noncommutative'' mathematics based on $C^*$-algebra theory [See also 58B32, 58B34, 58J22] | {"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": 0.6254844665527344, "perplexity": 551.3995435474355}, "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/1410657136494.66/warc/CC-MAIN-20140914011216-00237-ip-10-234-18-248.ec2.internal.warc.gz"} |
https://www.neetprep.com/question/26303-catalytic-reaction-involving-formation-ammonia-Habers-process-NH--NH-rate-appearance-NH-measured--x--mol-LS-rate-disappearance-H-will--x--mol-LS--x--mol-LS--x--mol-LS--x--mol-LS/54-Chemistry--Chemical-Kinetics/662-Chemical-Kinetics | # NEET Chemistry Chemical Kinetics Questions Solved
In a catalytic reaction involving the formation of ammonia by Haber's process N2+3H2 → 2NH3, the rate of appearance of NH3 was measured as 2.5 x 10-4 mol L-1S-1 The rate of disappearance of H2 will be
1. 2.5 x 10-4 mol L-1S-1
2. 1.25 x 10-4 mol L-1S-1
3. 3.75 x 10-4 mol L-1S-1
4. 15.00 x 10-4 mol L-1S-1
(3) N2+3H2 → 2N3
-1/3dH2/dt = -1/2dNH2/dt
-dH2/dt = 1/2x3x2.5x10-4
-dH2/dt = 3.75 x 10-4 mol L-1S-1
Difficulty Level:
• 8%
• 21%
• 66%
• 6%
Crack NEET with Online Course - Free Trial (Offer Valid Till August 25, 2019) | {"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": 0.9166544079780579, "perplexity": 29099.315345854895}, "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-2019-35/segments/1566027317847.79/warc/CC-MAIN-20190823041746-20190823063746-00060.warc.gz"} |
https://cs.stackexchange.com/questions/11678/upper-bound-on-register-machine-contents | # Upper bound on register machine contents
I am doing some work on register machine theory which revolves around a 2-register register machine and attempting to show that it is not possible to compute an upper-bound on the final contents of its two registers on the basis of its program code and initial input, in halting configurations only. I believe this can be related in some way to the busy beaver problem, but I cannot quite see how, and the stipulations that it is for halting configurations only has confused me somewhat.
What do I know so far?
• Clearly a register machine configuration specified by the 3-tuple (instruction label, register 0, register 1) has an infinite number of possible states, owing to the abstract nature of the machines, as no practical limit is imposed on the size of the natural numbers which can be stored in each register.
• I considered whether I could simply define a partial function $f : \mathbb{N}^3 \to \mathbb{N}$ where the arguments are the program encoded as a natural number and the initial contents of the two registers, but I do not think this gets me anywhere. I defined the function to be undefined when the partial function computed by the register machine specification is undefined on the given input, as the problem specifies computing the upper bound for halting configurations only.
Therefore, I cannot use a diagonal argument to suggest it would imply the halting problem, because being undefined for a non-halting configuration suggests it would not.
• Secondly, I tried to come up with a proof on the basis that there is an infinite number of possible configurations which a 2-register machine can be in. In particular, there is an infinite number of possible programs $e \in \mathbb{N}$ which could be executed, and each of those programs can be executed on an infinite number of initial register configurations $\mathbb{N}^2$.
By construction, if there is a machine which can decide this partial function for any given combination, then I thought it may be the case that it required an infinite number of states in which to do so - which is of course not possible, as a register machine must be specified by a finite number of instructions.
I am not confident that either approach is correct or not, and wonder whether either of the above is a correct tact or if a formal proof exists for this? | {"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": 0.8574950695037842, "perplexity": 213.968141688469}, "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/1570986660323.32/warc/CC-MAIN-20191015205352-20191015232852-00015.warc.gz"} |
https://www.mersenneforum.org/showpost.php?s=d726c35fc2cddde5a73db0a71a9fbc0c&p=544489&postcount=6 | Thread: Not the largest prime View Single Post
2020-05-03, 01:46 #6
Dr Sardonicus
Feb 2017
Nowhere
66478 Posts
Quote:
Originally Posted by Tomws And secondly given the well known proof that there are an infinite number of primes, how many digits are there in the answer if all primes less than or equal to 'my' prime are multiplied together?
Believe it or not, this question runs you smack-dab into the Prime Number Theorem (PNT)!
Alas, the answer is not known as precisely as one might wish, but still...
What you want is a "reasonable" estimate for
log(2) + log(3) + ... + log(p),
where p is the largest prime <= X, X some "large" positive number. In PNT-related literature, it is the natural log, log to the base e, or ln, that is used. And a statement equivalent to PNT is
$\sum_{p\le X}\ln(p) \;\sim \; X$
(ratio of RHS to LHS approaches 1 as X increases without bound) so that the number of decimal digits in the product of the primes up to X is something like X/ln(10). | {"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": 0, "mimetex.cgi": 1, "/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": 0.827121376991272, "perplexity": 786.8274820252878}, "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-2020-40/segments/1600402128649.98/warc/CC-MAIN-20200930204041-20200930234041-00055.warc.gz"} |
http://www.astroml.org/book_figures/chapter3/fig_uniform_mean.html | # Convergence of mean for uniformly distributed values¶
Figure 3.21.
A comparison of the sample-size dependence of two estimators for the location parameter of a uniform distribution, with the sample size ranging from N = 100 to N =10,000. The estimator in the top panel is the sample mean, and the estimator in the bottom panel is the mean value of two extreme values. The theoretical 1-, 2-, and 3-sigma contours are shown for comparison. When using the sample mean to estimate the location parameter, the uncertainty decreases proportionally to 1/ N, and when using the mean of two extreme values as 1/N. Note different vertical scales for the two panels.
The two methods of estimating the mean are:
• , with an error that scales as .
• , with an error that scales as .
The shaded regions on the plot show the expected 1, 2, and 3- error. Notice the difference in scale between the y-axes of the two plots.
# Author: Jake VanderPlas
# The figure produced by this code is published in the textbook
# "Statistics, Data Mining, and Machine Learning in Astronomy" (2013)
# To report a bug or issue, use the following forum:
import numpy as np
from matplotlib import pyplot as plt
from scipy.stats import uniform
#----------------------------------------------------------------------
# This function adjusts matplotlib settings for a uniform feel in the textbook.
# Note that with usetex=True, fonts are rendered with LaTeX. This may
# result in an error if LaTeX is not installed on your system. In that case,
# you can set usetex to False.
if "setup_text_plots" not in globals():
from astroML.plotting import setup_text_plots
setup_text_plots(fontsize=8, usetex=True)
#------------------------------------------------------------
# Generate the random distribution
np.random.seed(0)
N = (10 ** np.linspace(2, 4, 1000)).astype(int)
mu = 0
W = 2
rng = uniform(mu - 0.5 * W, W) # uniform distribution between mu-W and mu+W
#------------------------------------------------------------
# Compute the cumulative mean and min/max estimator of the sample
mu_estimate_mean = np.zeros(N.shape)
mu_estimate_minmax = np.zeros(N.shape)
for i in range(len(N)):
x = rng.rvs(N[i]) # generate N[i] uniformly distributed values
mu_estimate_mean[i] = np.mean(x)
mu_estimate_minmax[i] = 0.5 * (np.min(x) + np.max(x))
# compute the expected scalings of the estimator uncertainties
N_scaling = 2. * W / N / np.sqrt(12)
root_N_scaling = W / np.sqrt(N * 12)
#------------------------------------------------------------
# Plot the results
fig = plt.figure(figsize=(5, 3.75))
# upper plot: mean statistic
ax.scatter(N, mu_estimate_mean, c='b', lw=0, s=4)
for nsig in (1, 2, 3):
ax.fill(np.hstack((N, N[::-1])),
np.hstack((nsig * root_N_scaling,
-nsig * root_N_scaling[::-1])), 'b', alpha=0.2)
ax.set_xlim(N[0], N[-1])
ax.set_ylim(-0.19, 0.199)
ax.set_ylabel(r'$\bar{\mu}$')
ax.xaxis.set_major_formatter(plt.NullFormatter())
ax.text(0.99, 0.95,
r'$\bar\mu = \mathrm{mean}(x)$',
ha='right', va='top', transform=ax.transAxes)
ax.text(0.99, 0.02,
r'$\sigma = \frac{1}{\sqrt{12}}\cdot\frac{W}{\sqrt{N}}$',
ha='right', va='bottom', transform=ax.transAxes)
# lower plot: min/max statistic
ax.scatter(N, mu_estimate_minmax, c='g', lw=0, s=4)
for nsig in (1, 2, 3):
ax.fill(np.hstack((N, N[::-1])),
np.hstack((nsig * N_scaling,
-nsig * N_scaling[::-1])), 'g', alpha=0.2)
ax.set_xlim(N[0], N[-1])
ax.set_ylim(-0.0399, 0.039)
ax.set_xlabel('$N$')
ax.set_ylabel(r'$\bar{\mu}$')
ax.text(0.99, 0.95,
r'$\bar\mu = \frac{1}{2}[\mathrm{max}(x) + \mathrm{min}(x)]$',
ha='right', va='top', transform=ax.transAxes)
ax.text(0.99, 0.02,
r'$\sigma = \frac{1}{\sqrt{12}}\cdot\frac{2W}{N}$',
ha='right', va='bottom', transform=ax.transAxes)
plt.show() | {"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": 0.8898191452026367, "perplexity": 5895.45488790962}, "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/1620243991921.61/warc/CC-MAIN-20210516232554-20210517022554-00344.warc.gz"} |
http://math.stackexchange.com/questions/150514/classifying-a-matrix-matrix-representation-of-an-operator-with-linear-operator | # Classifying A Matrix - matrix representation of an operator with linear operators as entries
Say that one has a matrix representation of an operator A with differential operators as entries in the matrix A.
Is this a non-linear matrix? Since the differential is a linear operator and A is composed of linear operators, I'm leaning towards A being a linear operator.
If one were to take the conjugate transpose of A, would the differential operators be modified? I'm trying to prove that A is anti-hermitian, and it seems to me that the differential operators would have to be negated when A is conjugate-transposed in order for A to be anti-hermitian.
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I think there are at least 2 questions here. Matrix acting on vectors is a linear operation. How do you define a non-linear matrix? With regards to hermitian operators, conjugate is usually defined as transposed and complex conjugate. Perhaps you could give an example you're working on? – Valentin May 27 '12 at 22:13 | {"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": 0.8872509002685547, "perplexity": 220.10213817458606}, "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/1466783397111.67/warc/CC-MAIN-20160624154957-00042-ip-10-164-35-72.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/power-series-expansion-of-hyperbolic-functions.289121/ | # Power Series expansion of hyperbolic functions
1. Feb 1, 2009
### thanksie037
1. The problem statement, all variables and given/known data
power series expansion of:
((cosh x)/(sinh x)) - (1/x)
2. Relevant equations
cosh x = (1/2)(ex + e-x)
sinh x = (1/2)(ex - e-x)
3. The attempt at a solution
what i have so far:
I simplified the first part of the eq to read :
e2x-1
e2x-1
2. Feb 1, 2009
### NoMoreExams
You simplified for it to be $$\frac{e^{2x}-1}{e^{2x}-1}$$? Isn't that just 1?
3. Feb 1, 2009
### mjsd
error in simplification:
$$\frac{e^{2x}+1}{e^{2x}-1}$$
4. Feb 1, 2009
### thanksie037
I'm sorry that was a typo. Should I just expand both was like you would ex? how about the 1/x part?
5. Feb 1, 2009
### NoMoreExams
I would and then hopefully things will cancel, for example what's the expansion for $$e^{2x} - 1$$?
6. Feb 2, 2009
### mjsd
How do one usually find the taylor series of a given function?
now you have a function, what do you do? | {"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": 0.8447192311286926, "perplexity": 3763.495458335277}, "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/1484560282935.68/warc/CC-MAIN-20170116095122-00315-ip-10-171-10-70.ec2.internal.warc.gz"} |
http://tex.stackexchange.com/questions/9136/beamer-xetex-right-to-left | # Beamer XeTeX Right to Left
I am preparing Farsi slides in beamer which is a right to left language just like Hebrew. I have problems in the presentation which I briefly discuss:
• The TOC is left to right:
• The itemize can be forced to be right to left but it flushes to the left
• the frame title is shown in the left (this one is solved thanks to Mr.Vafa Khalighi the solution is \setbeamertemplate{frametitle}[default][right] command)
I found this web site very helpful to solve some problems, but the mentioned problems are still unresolved. the code is shown below
% XeLaTeX can use any Mac OS X font. See the setromanfont command below.
% Input to XeLaTeX is full Unicode, so Unicode characters can be typed directly into the source.
% The next lines tell TeXShop to typeset with xelatex, and to open and save the source with Unicode encoding.
%!TEX TS-program = xelatex
%!TEX encoding = UTF-8 Unicode
\documentclass[11pt]{beamer}
\usetheme{Warsaw}
\usecolortheme{crane}
%\usepackage{geometry} % See geometry.pdf to learn the layout options. There are lots.
%\geometry{letterpaper} % ... or a4paper or a5paper or ...
%\geometry{landscape} % Activate for for rotated page geometry
%\usepackage[parfill]{parskip} % Activate to begin paragraphs with an empty line rather than an indent
\usepackage{graphicx}
\usepackage{amssymb}
% Will Robertson's fontspec.sty can be used to simplify font choices.
% To experiment, open /Applications/Font Book to examine the fonts provided on Mac OS X,
% and change "Hoefler Text" to any of these choices.
\TeXXeTstate=1
\usepackage{fontspec,xltxtra,xunicode}
\usepackage{bidi}
\defaultfontfeatures{Mapping=tex-text}
\setromanfont[Mapping=tex-text]{X Zar}
\setsansfont[Scale=MatchLowercase,Mapping=tex-text]{Gill Sans}
\setsansfont[Scale=MatchLowercase,Mapping=tex-text]{X Zar}
\setmonofont[Scale=MatchLowercase]{X Zar}
% \newfontfamily{\A}{X Zar}
\title{امنیت در اجرای همروند یک پروتکل احراز اصالت}
\author{یاسر صبحدل}
\date{\today}
\begin{document}
\frame{\titlepage}
\section[چارچوب]{}
\frame{\tableofcontents}
%\maketitle
% For many users, the previous commands will be enough.
% If you want to directly input Unicode, add an Input Menu or Keyboard to the menu bar
% using the International Panel in System Preferences.
% Unicode must be typeset using a font containing the appropriate characters.
% Remove the comment signs below for examples.
% \newfontfamily{\H}[Scale=0.9]{Lucida Grande}
% \newfontfamily{\J}[Scale=0.85]{Osaka}
\section{مقدمه}
\subsection{مروری بر پروتکلهای احراز اصالت}
\frame
{
\frametitle{محاسبات چندجانبه امن}
\begin{flushright}
از ۳ منظر مورد بررسی قرار میگیرد:\\
\end{flushright}
\setRL
{
\begin{itemize}
\item مورد اول
\item مورد دوم
\end{itemize}
}
}
\end{document}
BTW, I just didn't use the \newfontfamily command because the whole document is persian and only some words are english, so I changed the main font with a persian one.
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Unfortunately there isn't good bidi support for beamer, which is what you would need to solve some of these problems. At least at the moment, the author of bidi doesn't seem willing to provide such support: bit.ly/faDMh0 – Alan Munn Jan 17 '11 at 13:02
Side remark: You should additionally use the polyglossia package (though it won't help with your immediate problem, as it relies on bidi for rtl text). – Caramdir Jan 17 '11 at 17:53
@user2716: nothing in therms of rtl (except that it includes bidi). But it does a variety of things that beamer does for standard latex (dates, numerals, etc.) – Caramdir Jan 19 '11 at 6:22
@user2716 Vafa, perhaps my choice of words wasn't the best. I realise that the job is a big task, and since everything most of us do is done on a volunteer basis, fixing beamer isn't on your agenda at the moment. Everyone appreciates your work on bidi. – Alan Munn Jan 20 '11 at 21:59
@user2716: Are you planning to fill in at least a bit of your profile at some point? (Suggestion: go to tex.stackexchange.com/users/edit/2716 and fill in something better than "user2716" for "Display Name".) – SamB Jan 21 '11 at 19:01
Yasser, use bidipresentation class, at Parsilatex website, you can find useful template and help to achieve your aim. | {"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": 0.7179206609725952, "perplexity": 6922.066827089426}, "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/1410657137190.70/warc/CC-MAIN-20140914011217-00266-ip-10-234-18-248.ec2.internal.warc.gz"} |
https://mathsnetalevel.com/215 | Go to content
Circles are described by the Cartesian equation:
where (a,b) is the centre and r is the radius of the circle.
The equation of the circle whose centre is at the origin is x^2+y^2=r^2
The equation of the unit circle whose centre is at the origin is x^2+y^2=1
## Summary/Background
Circles can be displayed on your graphic calculator, for example, on the TI-83: Select the Y= screen:Enter Y1 = √(R-(X-A))+BEnter Y2 = -√(R-(X-A))+BThen select the GRAPH screen. You can then choose different values for the constants A, B and R. For example, to make R = 4, press 4 ALPHA R. You may also need to adjust the scaling to get a good display of the circle.
You can get a better display of the maths by downloading special TeX fonts from jsMath. In the meantime, we will do the best we can with the fonts you have, but it may not be pretty and some equations may not be rendered correctly.
## Glossary
### cartesian equation
An equation that shows a relationship between the x and y cartesian coordinates.
### circle
a conic curve with equation (x-a)²+(y-b)²=r²
### equation
A statement that two mathematical expressions are equal.
### graph
A diagram showing a relationship between two variables.
The diagram shows a vertical y axis and a horizontal x axis.
### origin
The point from where all measurements of coordinates are made; usually the point where the two axes of a graph cross.
### union
The union of two sets A and B is the set containing all the elements of A and B.
Full Glossary List
## This question appears in the following syllabi:
SyllabusModuleSectionTopicExam Year
AQA A-Level (UK - Pre-2017)C1Coordinate geometryCircles - geometry-
AQA AS Maths 2017Pure MathsStraight Lines and CirclesCircle Geometry-
AQA AS/A2 Maths 2017Pure MathsStraight Lines and CirclesCircle Geometry-
CBSE XI (India)Coordinate GeometryConic SectionsCircle, parabola, ellipse, hyperbola, point & straight line-
CCEA A-Level (NI)C2Coordinate geometryCircles - geometry-
Edexcel A-Level (UK - Pre-2017)C2Coordinate geometryCircles - geometry-
Edexcel AS Maths 2017Pure MathsCirclesCircle Geometry-
Edexcel AS/A2 Maths 2017Pure MathsCirclesCircle Geometry-
Methods (UK)M1Coordinate geometryCircles - geometry-
OCR A-Level (UK - Pre-2017)C1Coordinate geometryCircles - geometry-
OCR AS Maths 2017Pure MathsLines and CirclesCircle Geometry-
OCR MEI AS Maths 2017Pure MathsLines and CirclesCircle Geometry-
OCR-MEI A-Level (UK - Pre-2017)C1Coordinate geometryCircles - geometry-
Pre-Calculus (US)C6Coordinate geometryCircles - geometry-
Pre-U A-Level (UK)2Coordinate geometryCircles - geometry-
Scottish (Highers + Advanced)HM2Coordinate geometryCircles - geometry-
Scottish HighersM2Coordinate geometryCircles - geometry-
Universal (all site questions)CCoordinate geometryCircles - geometry-
WJEC A-Level (Wales)C2Coordinate geometryCircles - geometry- | {"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": 0.8077992796897888, "perplexity": 6334.484284487506}, "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/1631780058263.20/warc/CC-MAIN-20210927030035-20210927060035-00223.warc.gz"} |
https://researchers.general.hokudai.ac.jp/profile/en.36980a110fbe9592520e17560c007669.html | Researcher Database
JINZENJI Masao Faculty of Science Mathematics Mathematics Associate Professor
Researcher Profile and Settings
Affiliation
• Faculty of Science Mathematics Mathematics
Job Title
Associate Professor
Research Interests
• Topological Field Theory
Research Areas
• Mathematics / Geometry
• Physics / Mathematical physics/Fundamental condensed matter physics
• Mathematics / Algebra
• Physics / Mathematical physics/Fundamental condensed matter physics
• Mathematics / Geometry
• 2007 - Associate Professor
Research Activities
Books etc
• Classical Mirror Symmetry
Springer Singapore 2018/04 978-981-13-0055-4 148 Single Work
MISC
• Masao Jinzenji 2017/12 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we outline geometrical proof of the generalized mirror transformation of genus 0 Gromov-Witten invariants of degree k hypersurface in CP^{N-1}.
• Masao Jinzenji, Masahide Shimizu Communications in Number Theory and Physics, Volume 7, Number 3, 411-468, 2013 2013/05 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we propose a geometrical approach to mirror computation of genus 0 Gromov-Witten invariants of CP^2. We use multi-point virtual structure constants, which are defined as intersection numbers of a compact moduli space of quasi maps from CP^1 to CP^2 with 2+n marked points. We conjecture that some generating functions of them produce mirror map and the others are translated into generating functions of Gromov-Witten invariants via the mirror map. We generalize this formalism to open string case. In this case, we have to introduce infinite number of deformation parameters to obtain results that agree with some known results of open Gromov-Witten invariants of CP^2. We also apply multi-point virtual structure constants to compute closed and open Gromov-Witten invariants of a non-nef hypersurface in projective space. This application simplifies the computational process of generalized mirror transformation.
• Masao Jinzenji, Masahide Shimizu International Journal of Geometric Methods in Modern Physics, Vol.11, No.1 (2014) 1450005 2011/08 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we generalize Walcher's computation of the open Gromov-Witten invariants of the quintic hypersurface to Fano and Calabi-Yau projective hypersurfaces. Our main tool is the open virtual structure constants. We also propose the generalized mirror transformation for the open Gromov-Witten invariants, some parts of which are proven explicitly. We also discuss possible modification of the multiple covering formula for the case of higher dimensional Calabi-Yau manifolds. The generalized disk invariants for some Calabi-Yau and Fano manifolds are shown and they are certainly integers after re-summation by the modified multiple covering formula. This paper also contains the direct integration method of the period integrals for higher dimensional Calabi-Yau hypersurfaces in the appendix.
• Masao Jinzenji Communications in Mathematical Physics, 323, 747--811 (2013) 2010/06 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we extend our geometrical derivation of expansion coefficients of mirror maps by localization computation to the case of toric manifolds with two K\"ahler forms. Especially, we take Hirzebruch surfaces F_{0}, F_{3} and Calabi-Yau hypersurface in weighted projective space P(1,1,2,2,2) as examples. We expect that our results can be easily generalized to arbitrary toric manifold.
• Masao Jinzenji Journal of Geometry and Physics, Vol. 61, Issue 8, (2011) 1564-1573 61- (8) 1564 -1573 2009/02 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we directly derive generalized mirror transformation of projective hypersurfaces up to degree 3 genus 0 Gromov-Witten invariants by comparing Kontsevich localization formula with residue integral representation of the virtual structure constants. We can easily generalize our method for rational curves of arbitrary degree except for combinatorial complexities.
• Brian Forbes, Masao Jinzenji Adv.Theor.Math.Phys.11:175-197,2007 2006/09 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We continue our study of equivariant local mirror symmetry of curves, i.e. mirror symmetry for X_k=O(k)+O(-2-k) over P^1 with torus action (lambda_1,lambda_2) on the bundle. For the antidiagonal action lambda_1=-lambda_2, we find closed formulas for the mirror map and a rational B model Yukawa coupling for all k. Moreover, we give a simple closed form for the B model genus 1 Gromov-Witten potential. For the diagonal action lambda_1=lambda_2, we argue that the mirror symmetry computation is equivalent to that of the projective bundle P(O+O(k)+O(-2-k)) over P^1. Finally, we outline the computation of equivariant Gromov-Witten invariants for A_n singularities and toric tree examples via mirror symmetry.
• Brian Forbes, Masao Jinzenji Int.J.Mod.Phys.A22:2327-2360,2007 2006/03 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We develop techniques for computing the equivariant local mirror symmetry of curves, i.e. mirror symmetry for O(k)+O(-2-k) over P^1 for k greater than 0. We also describe related methods for dealing with mirror symmetry of non-nef toric varieties. The basic tools are equivariant I functions and their Birkhoff factorization.
• Masao Jinzenji, Toru Sasaki JHEP 0209 (2002) 002 2002/03 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We propose a recipe for determination of the partition function of ${\cal N}=4$ $ADE$ gauge theory on $K3$ by generalizing our previous results of the SU(N) case. The resulting partition function satisfies Montonen-Olive duality for $ADE$ gauge group.
• Masao Jinzenji, Toru Sasaki JHEP 0112:002,2001 2001/09 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We derive the partition function of {\cal N}=4 supersymmetric Yang-Mills theory on orbifold-T^4/{\bf Z}_2 for gauge group SU(N). We generalize the method of our previous work for the SU(2) case to the SU(N) case. The resulting partition function is represented as the sum of the product of G\"ottche formula of singular quotient space $T^4/{\bf Z}_2$ and of blow-up formulas including A_{N-1} theta series with level N.
• Masao Jinzenji Int.J.Math. 13 (2002) 445-478 2001/09 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we discuss some applications of Givental's differential equations to enumerative problems on rational curves in projective hypersurfaces. Using this method, we prove some of the conjectures on the structure constants of quantum cohomology of projective hypersurfaces, proposed in our previous article. Moreover, we clarify the correspondence between the virtual structure constants and Givental's differential equations when the projective hypersurface is Calabi-Yau or general type.
• Masao Jinzenji Mod.Phys.Lett. A15 (2000) 629-650 15- 629 -650 2000/02 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we propose another characterization of the generalized mirror transformation on the quantum cohomology rings of general type projective hypersurfaces. This characterics is useful for explicit determination of the form of the generalized mirror transformation. As applications, we rederive the generalized mirror transformation up to $d=3$ rational Gromov-Witten invariants obtained in our previous article, and determine explicitly the the generalized mirror transformation for the $d=4, 5$ rational Gromov-Witten invariants in the case when the first Chern class of the hypersurface equals $-H$ (i.e., $k-N=1$).
• Masao Jinzenji, Toru Sasaki Mod.Phys.Lett. A16 (2001) 411-428 2000/12 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We derive the partition function of N=4 supersymmetric Yang-Mills theory on orbifold-$T^4/{\bf Z}_2$. In classical geometry, K3 surface is constructed from the orbifold-$T^4/{\bf Z}_2$. Along the same way as the orbifold construction, we construct the partition function of K3 surface from orbifold-$T^4/{\bf Z}_2$. The partition function is given by the product of the contribution of the untwisted sector of $T^4/{\bf Z}_2$, and that of the twisted sector of $T^4/{\bf Z}_2$ i.e., ${\cal O}(-2)$ curve blow-up formula.
• Brian Forbes, Masao Jinzenji JHEP0603:061,2006 2005/11 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we first derive an intrinsic definition of classical triple intersection numbers of K_S, where S is a complex toric surface, and use this to compute the extended Picard-Fuchs system of K_S of our previous paper, without making use of the instanton expansion. We then extend this formalism to local fourfolds K_X, where X is a complex 3-fold. As a result, we are able to fix the prepotential of local Calabi-Yau threefolds K_S up to polynomial terms of degree 2. We then outline methods of extending the procedure to non canonical bundle cases.
• Masao Jinzenji Letters in Mathematical Physics, Vol.86, No.2-3, 99-114 (2008) 86- (2-3) 99 -114 2007/12 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we derive the virtual structure constants used in mirror computation of degree k hypersurface in CP^{N-1}, by using localization computation applied to moduli space of polynomial maps from CP^{1} to CP^{N-1} with two marked points. We also apply this technique to non-nef local geometry O(1)+O(-3)->CP^{1} and realize mirror computation without using Birkhoff factorization.
• Masao Jinzenji Int.J.Mod.Phys. A20 (2005) 2131-2156 20- (10) 2131 -2156 2003/10 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we explicitly derive the generalized mirror transformation of quantum cohomology of general type projective hypersurfaces, proposed in our previous article, as an effect of coordinate change of the virtual Gauss-Manin system.
• Tohru Eguchi, Masao Jinzenji JHEP 0002 (2000) 028 1999/11 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We discuss a possible generalization of the Calabi-Yau/Landau-Ginzburg correspondence to a more general class of manifolds. Specifically we consider the Fermat type hypersurfaces $M_N^k$: $\sum_{i=1}^N X_i^k =0$ in ${\bf CP}^{N-1}$ for various values of k and N. When k2. We assume that this massless sector is described by a Landau-Ginzburg (LG) theory of central charge $c=3N(1-2/k)$ with N chiral fields with U(1) charge $1/k$. We compute the topological invariants (elliptic genera) using LG theory and massive vacua and compare them with the geometrical data. We find that the results agree if and only if k=even and N=even. These are the cases when the hypersurfaces have a spin structure. Thus we find an evidence for the geometry/LG correspondence in the case of spin manifolds.
• M. Jinzenji Mod.Phys.Lett. A15 (2000) 101-120 15- 101 -120 1999/10 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we propose the formulas that compute all the rational structural constants of the quantum K\"ahler sub-ring of Fano hypersurfaces.
• Brian Forbes, Masao Jinzenji J.Math.Phys. 46 (2005) 082302 46- (8) 1 -82302 2005/03 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We propose an extended set of differential operators for local mirror symmetry. If $X$ is Calabi-Yau such that $\dim H_4(X,\Z)=0$, then we show that our operators fully describe mirror symmetry. In the process, a conjecture for intersection theory for such $X$ is uncovered. We also find new operators on several examples of type $X=K_S$ through similar techniques. In addition, open string PF systems are considered.
• Jinzenji Masao Soryushiron Kenkyu 97- (4) D119 -D127 1998/07 [Not refereed] [Not invited]
In this paper, we review recent discovery of connection between Virasoro algebra and topological sigma model coupled to topological gravity.
• Brian Forbes, Masao Jinzenji Commun.Num.Theor.Phys.1,2007 729 2007/09 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We solve the problem of equivariant mirror symmetry for O(-3)->P^2 for the (three) cases of one independent equivariant parameter. This gives a decomposition of mirror symmetry for local P^2 into that of three subspaces, each of which may be considered independently. Finally, we give a new interpretation of mirror symmetry for O(k)+O(-2-k)->P^1.
• M. Jinzenji Int.J.Mod.Phys.A15:1557-1596,2000 1998/11 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In this paper, we study the structure of the quantum cohomology ring of a projective hypersurface with non-positive 1st Chern class. We prove a theorem which suggests that the mirror transformation of the quantum cohomology of a projective Calabi-Yau hypersurface has a close relation with the ring of symmetric functions, or with Schur polynomials. With this result in mind, we propose a generalized mirror transformation on the quantum cohomology of a hypersurface with negative first Chern class and construct an explicit prediction formula for three point Gromov-Witten invariants up to cubic rational curves. We also construct a projective space resolution of the moduli space of polynomial maps, which is in a good correspondence with the terms that appear in the generalized mirror transformation.
• Tohru Eguchi, Masao Jinzenji, Chuan-Sheng Xiong Nucl.Phys. B510 (1998) 608-622 1997/09 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
In our previous article we have proposed that the Virasoro algebra controls the quantum cohomology of Fano varieties at all genera. In this paper we construct a free field description of Virasoro operators and quantum cohomology. We shall show that to each even (odd) homology class of a K\"{a}hler manifold we have a free bosonic (fermionic) field and Virasoro operators are given by a simple bilinear form of these fields. We shall show that the Virasoro condition correctly reproduces the Gromov-Witten invariants also in the case of manifolds with non-vanishing non-analytic classes ($h^{p,q}\not=0,p\not=q$) and suggest that the Virasoro condition holds universally for all compact smooth K\"{a}hler manifolds.
• A. Collino, M. Jinzenji Commun.Math.Phys. 206 (1999) 157-183 1996/11 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We give an explicit procedure which computes for degree $d \leq 3$ the correlation functions of topological sigma model (A-model) on a projective Fano hypersurface $X$ as homogeneous polynomials of degree $d$ in the correlation functions of degree 1 (number of lines). We extend this formalism to the case of Calabi-Yau hypersurfaces and explain how the polynomial property is preserved. Our key tool is the construction of universal recursive formulas which express the structural constants of the quantum cohomology ring of $X$ as weighted homogeneous polynomial functions in the constants of the Fano hypersurface with the same degree and dimension one more. We propose some conjectures about the existence and the form of the recursive formulas for the structural constants of rational curves of arbitrary degree. Our recursive formulas should yield the coefficients of the hypergeometric series used in the mirror calculation. Assuming the validity of the conjectures we find the recursive laws for rational curves of degree 4 and 5.
• Masao Jinzenji J.Math.Phys. 38 (1997) 6613-6638 38- (12) 6613 -6638 1995/11 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
Using the torus action method, we construct one variable polynomial representation of quantum cohomology ring for degree $k$ hypersurface in $CP^{N-1}$ . The results interpolate the well-known result of $CP^{N-2}$ model and the one of Calabi-Yau hypersuface in $CP^{N-1}$. We find in $k\leq N-2$ case, principal relation of this ring have very simple form compatible with toric compactification of moduli space of holomorphic maps from $CP^{1}$ to $CP^{N-1}$.
• Masao Jinzenji Int.J.Mod.Phys. A12 (1997) 5775-5802 12- (32) 5775 -5802 1995/05 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We calculate correlation functions of topological sigma model (A-model) on Calabi-Yau hypersurfaces in $CP^{N-1}$ using torus action method. We also obtain path-integral represention of free energy of the theory coupled to gravity.
• Masao Jinzenji, Masaru Nagura Int.J.Mod.Phys. A11 (1996) 1217-1252 1994/09 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
We consider an (N-2)-dimensional Calabi-Yau manifold which is defined as the zero locus of the polynomial of degree N (of Fermat type) in CP^{N-1} and its mirror manifold. We introduce the (N-2)-point correlation function (generalized Yukawa coupling) and evaluate it both by solving the Picard-Fuchs equation for period integrals in the mirror manifold and also by explicitly calculating the contribution of holomorphic maps of degree 1 to the Yukawa coupling in the Calabi-Yau manifold using the method of Algebraic geometry...
• Masao Jinzenji, Yi Sun Int.J.Mod.Phys. A11 (1996) 171-202 11- (1) 171 -202 1994/12 [Not refereed] [Not invited] Institution technical report and pre-print, etc.
Using the associativity relations of the topological Sigma Models with target spaces, $CP^3, CP^4$ and $Gr(2,4)$ , we derive recursion relations of their correlation and evaluate them up to certain order in the expansion over the instantons. The expansion coeffieients are regarded as the number of rational curves in $CP^3, CP^4$ and $Gr(2,4)$ which intersect various types of submanifolds corresponding to the choice of BRST invariant operators in the correlation functions.
Research Grants & Projects
• Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(C))
Date (from‐to) : 2010 -2012
Author : Masao JINZENJI
北海道大学We reconstructed the mirror map, which is used in the mirror computation of Gromov-Witten invariants, as a generating function of intersection numbers of the moduli space of quasi maps. With this result, we reinterpreted the mirror computation of Gromov-Witten invariants as a way of computing Gromov-Witten invariants by using the difference of compactification of the moduli space of holomorphic maps. We also used this reconstruction to generalize the mirror computation of open Gromov-Witten invariants to wide class of complex manifolds.
Educational Activities
Teaching Experience
• 現代数学概説
開講年度 : 2017
課程区分 : 修士課程
開講学部 : 理学院
• Geometry
開講年度 : 2017
課程区分 : 修士課程
開講学部 : 理学院
キーワード : はめ込みとしずめ込み 横断性 交差理論 ポアンカレ－ホップの定理
• Overview of Modern Mathematics
開講年度 : 2017
課程区分 : 修士課程
開講学部 : 理学院
キーワード : 【有限鏡映群について】 鏡映群, 折り返し, 平面分割, 空間分割 【有理曲線の数え上げとミラー対称性】 有理曲線、グロモフ‐ウィッテン不変量、ミラー対称性
• Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
開講年度 : 2017
課程区分 : 修士課程
開講学部 : 大学院共通科目
キーワード : 【有限鏡映群について】 鏡映群, 折り返し, 平面分割, 空間分割 【有理曲線の数え上げとミラー対称性】 有理曲線、グロモフ‐ウィッテン不変量、ミラー対称性
開講年度 : 2017
課程区分 : 学士課程
開講学部 : 理学部
キーワード : はめ込みとしずめ込み 横断性 交差理論 ポアンカレ－ホップの定理
• Calculus I
開講年度 : 2017
課程区分 : 学士課程
開講学部 : 全学教育
キーワード : 数列, 収束, 関数, 極限, 微分, 偏微分, テイラ－の定理
• Calculus II
開講年度 : 2017
課程区分 : 学士課程
開講学部 : 全学教育
キーワード : 原始関数, 積分, 重積分, リ－マン和, 変数変換
• Exercises on Basic Mathematics C
開講年度 : 2017
課程区分 : 学士課程
開講学部 : 理学部
キーワード : 実数、数列、収束、連続、微分、積分 | {"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": 0.8603803515434265, "perplexity": 2439.166306371594}, "config": {"markdown_headings": false, "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-2019-43/segments/1570986659097.10/warc/CC-MAIN-20191015131723-20191015155223-00500.warc.gz"} |
https://www.jobilize.com/online/course/5-5-linear-algebra-other-norms?qcr=www.quizover.com | # 5.5 Linear algebra: other norms
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This module is part of the collection, A First Course in Electrical and Computer Engineering . The LaTeX source files for this collection were created using an optical character recognition technology, and because of this process there may be more errors than usual. Please contact us if you discover any errors.
Sometimes we find it useful to use a different definition of distance, corresponding to an alternate norm for vectors. For example, consider the l-norm defined as
${||x||}_{1}=\left(|{x}_{1}|+|{x}_{2}|+\cdots +|{x}_{n}|\right),$
where $|{x}_{i}|$ is the magnitude of component x i . There is also the sup-norm , the “supremum” or maximum of the components ${x}_{1},...,{x}_{n}$ :
${||x||}_{sup}=max\left(|{x}_{1}|,|{x}_{2}|,...,|{x}_{n}|\right).$
The following examples illustrate what the Euclidean norm, the l-norm, and the sup-norm look like for typical vectors.
Consider the vector $x=-3l2$ . Then
1. $||x||={\left[{\left(-3\right)}^{2}+{\left(1\right)}^{2}+{\left(2\right)}^{2}\right]}^{1/2}={\left(14\right)}^{1/2}$ ;
2. ${||x||}_{1}=\left(|-3|+|1|+|2|\right)=6$ ; and
3. ${||x||}_{sup}=max\left(|-3|,|1|,|2|\right)=3.$
Figure 1 shows the locus of two-component vectors $x={x}_{1}{x}_{2}$ with the property that $||x||={1,||x||}_{1}=1$ , or ${||x||}_{sup}=1.$
The next example shows how the l-norm is an important part of city life.
The city of Metroville was laid out by mathematicians as shown in Figure 2 . A person at the intersection of Avenue 0 and Street $-2$ (point A ) is clearly two blocks from the center of town (point C). This is consistent with both the Euclidean norm
$||A||=\sqrt{{0}^{2}+{\left(-2\right)}^{2}}=\sqrt{4}=2$
and the l-norm
${||A||}_{1}=\left(|0|+|-2|\right)=2.$
But how far from the center of town is point $B$ at the intersection of Avenue-2 and Street 1? According to the Euclidean norm, the distance is
$||B||=\sqrt{{\left(-2\right)}^{2}+{\left(1\right)}^{2}}=\sqrt{5}.$
While it is true that point $B$ is $\sqrt{5}$ blocks from $C$ , it is also clear that the trip would be three blocks by any of the three shortest routes on roads. Theappropriate norm is the l-norm:
$|{1}^{B}{||}_{1}=\left(|-2|+|1|\right)=3.$
Even more generally, we can define a norm for each value of $p$ from 1 to infinity. The so-called p-norm is
${|Ix||}_{p}=\left(|{x}_{1}{|}^{p}+|{x}_{2}{|}^{p}+\cdots +|{x}_{n}{{|}^{p}\right)}^{1/p}.$
DEMO 4.1 (MATLAB). From the command level of MATLAB, type the following lines:
Check to see whether the answer agrees with the definition of vector subtraction. Now type
Check the answer to see whether it agrees with the definition of scalar multiplication. Now type
This is how MATLAB does the inner product. Check the result. Type
Now type your own MATLAB expression to find the cosine of the angle between vectors $x$ and $y$ . Put the result in variable $t$ . Then find the angle $\theta$ by typing
The angle $\theta$ is in radians. You may convert it to degrees if you wish by multiplying it by $180/\pi$ :
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
how did you get the value of 2000N.What calculations are needed to arrive at it
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Got questions? Join the online conversation and get instant answers! | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 28, "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": 0.5385878086090088, "perplexity": 1536.28866577817}, "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-2019-39/segments/1568514574710.66/warc/CC-MAIN-20190921231814-20190922013814-00297.warc.gz"} |
https://www.physicsforums.com/threads/help-with-a-pde-system.155888/ | # Help with a PDE system
1. Feb 12, 2007
### Magister
Hi
Solving a Killing vector problem, in General Relativity, I got the following PDE system:
$$\frac{\partial X^0}{\partial x}=0$$
$$\frac{\partial X^1}{\partial y}=0$$
$$\frac{\partial X^2}{\partial z}=0$$
$$\frac{\partial X^0}{\partial y} + \frac{\partial X^1}{\partial x}=0$$
$$\frac{\partial X^0}{\partial z} + \frac{\partial X^2}{\partial x}=0$$
$$\frac{\partial X^1}{\partial z} + \frac{\partial X^2}{\partial y}=0$$
where $X^a , a=0,1,2$ are the three components of the Killing vector that I am looking for. I have spend a lot of time trying to solve this system but I am not getting any solution.
Thanks for any idea.
Last edited: Feb 12, 2007
2. Feb 12, 2007
### Mute
I don't know what a Killing vector is, so assuming that is has a "nice" form, where by "nice" I mean it satisfies the continuity conditions, etc, which mean that equality between mixed partial derivatives holds, i.e., $\partial_{x}\partial_{y} = \partial_{y}\partial_{x}$, then it follows that
$$\partial_{yy}X^{0} = 0$$
$$\partial_{zz}X^{0} = 0$$
$$\partial_{xx}X^{1} = 0$$
$$\partial_{zz}X^{1} = 0$$
$$\partial_{xx}X^{2} = 0$$
$$\partial_{yy}X^{2} = 0$$
You get these by differentiating your coupled equations with respect to one of the variables for which the derivative of $X^a$ is zero, then swap the order of the partials and that term goes away. You can do that twice with each equation.
I haven't thought of this much past that - my guess is that integrating those and then making sure the arbitrary functions of integration/boundary conditions work out should be sufficient.
Last edited: Feb 12, 2007
3. Feb 12, 2007
### Magister
Yes, you can assume that they are "nice".
Can you tell me how many solutions should I expect and why? The problem is that I always get lost with the vairous solutions I get.
Thanks for the replies
4. Feb 13, 2007
### Mute
Well, the second order differential equations will give you two linearly independent solutions. In this case, since the derivative is equal to zero, your solutions will just be a term proportional to the variable and a constant - where you have to note that the constant is actually a function of the other two variables which you did not differentiate with respect to.
You have three differential equations for each $X^a$, two of which are second order and one of which is first order. Solving all three is easy, and so after that you just have to match up the arbitrary functions so that the $X^a$ satisfies all three of its differential equations. | {"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": 0.969767153263092, "perplexity": 269.54724868626494}, "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-2017-39/segments/1505818687906.71/warc/CC-MAIN-20170921205832-20170921225832-00156.warc.gz"} |
https://worldwidescience.org/topicpages/a/aluminum+hydride+phases.html | #### Sample records for aluminum hydride phases
1. Luminescent properties of aluminum hydride
Energy Technology Data Exchange (ETDEWEB)
Baraban, A.P.; Gabis, I.E.; Dmitriev, V.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Dobrotvorskii, M.A., E-mail: mstislavd@gmail.com [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Kuznetsov, V.G. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Matveeva, O.P. [National Mineral Resources University, Saint Petersburg 199106 (Russian Federation); Titov, S.A. [Petersburg State University of Railway Transport, Saint-Petersburg 190031 (Russian Federation); Voyt, A.P.; Elets, D.I. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation)
2015-10-15
We studied cathodoluminescence and photoluminescence of α-AlH{sub 3}– a likely candidate for use as possible hydrogen carrier in hydrogen-fueled vehicles. Luminescence properties of original α-AlH{sub 3} and α-AlH{sub 3} irradiated with ultraviolet were compared. The latter procedure leads to activation of thermal decomposition of α-AlH{sub 3} and thus has a practical implementation. We showed that the original and UV-modified aluminum hydride contain luminescence centers ‐ structural defects of the same type, presumably hydrogen vacancies, characterized by a single set of characteristic bands of radiation. The observed luminescence is the result of radiative intracenter relaxation of the luminescence center (hydrogen vacancy) excited by electrons or photons, and its intensity is defined by the concentration of vacancies, and the area of their possible excitation. UV-activation of the dehydrogenation process of aluminum hydride leads to changes in the spatial distribution of the luminescence centers. For short times of exposure their concentration increases mainly in the surface regions of the crystals. At high exposures, this process extends to the bulk of the aluminum hydride and ends with a decrease in concentration of luminescence centers in the surface region. - Highlights: • Aluminum hydride contains hydrogen vacancies which serve as luminescence centers. • The luminescence is the result of radiative relaxation of excited centers. • Hydride UV-irradiation alters distribution and concentration of luminescence centers.
2. Regeneration of aluminum hydride
Science.gov (United States)
Graetz, Jason Allan; Reilly, James J; Wegrzyn, James E
2012-09-18
The present invention provides methods and materials for the formation of hydrogen storage alanes, AlH.sub.x, where x is greater than 0 and less than or equal to 6 at reduced H.sub.2 pressures and temperatures. The methods rely upon reduction of the change in free energy of the reaction between aluminum and molecular H.sub.2. The change in free energy is reduced by lowering the entropy change during the reaction by providing aluminum in a state of high entropy, and by increasing the magnitude of the change in enthalpy of the reaction or combinations thereof.
3. Activated aluminum hydride hydrogen storage compositions and uses thereof
Science.gov (United States)
Sandrock, Gary; Reilly, James; Graetz, Jason; Wegrzyn, James E.
2010-11-23
In one aspect, the invention relates to activated aluminum hydride hydrogen storage compositions containing aluminum hydride in the presence of, or absence of, hydrogen desorption stimulants. The invention particularly relates to such compositions having one or more hydrogen desorption stimulants selected from metal hydrides and metal aluminum hydrides. In another aspect, the invention relates to methods for generating hydrogen from such hydrogen storage compositions.
4. Hydrogen storage in sodium aluminum hydride.
Energy Technology Data Exchange (ETDEWEB)
Ozolins, Vidvuds; Herberg, J.L. (Lawrence Livermore National Laboratories, Livermore, CA); McCarty, Kevin F.; Maxwell, Robert S. (Lawrence Livermore National Laboratories, Livermore, CA); Stumpf, Roland Rudolph; Majzoub, Eric H.
2005-11-01
Sodium aluminum hydride, NaAlH{sub 4}, has been studied for use as a hydrogen storage material. The effect of Ti, as a few mol. % dopant in the system to increase kinetics of hydrogen sorption, is studied with respect to changes in lattice structure of the crystal. No Ti substitution is found in the crystal lattice. Electronic structure calculations indicate that the NaAlH{sub 4} and Na{sub 3}AlH{sub 6} structures are complex-ionic hydrides with Na{sup +} cations and AlH{sub 4}{sup -} and AlH{sub 6}{sup 3-} anions, respectively. Compound formation studies indicate the primary Ti-compound formed when doping the material at 33 at. % is TiAl{sub 3} , and likely Ti-Al compounds at lower doping rates. A general study of sorption kinetics of NaAlH{sub 4}, when doped with a variety of Ti-halide compounds, indicates a uniform response with the kinetics similar for all dopants. NMR multiple quantum studies of solution-doped samples indicate solvent interaction with the doped alanate. Raman spectroscopy was used to study the lattice dynamics of NaAlH{sub 4}, and illustrated the molecular ionic nature of the lattice as a separation of vibrational modes between the AlH{sub 4}{sup -} anion-modes and lattice-modes. In-situ Raman measurements indicate a stable AlH{sub 4}{sup -} anion that is stable at the melting temperature of NaAlH{sub 4}, indicating that Ti-dopants must affect the Al-H bond strength.
5. Photoelectron spectroscopy of boron aluminum hydride cluster anions
Energy Technology Data Exchange (ETDEWEB)
Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Gantefoer, Gerd; Bowen, Kit H., E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Li, Xiang [Center for Space Science and Technology, University of Maryland–Baltimore County, Baltimore, Maryland 21250 (United States); Kiran, Boggavarapu, E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry and Physics, McNeese State University, Lake Charles, Louisiana 70609 (United States); Kandalam, Anil K. [Department of Physics, West Chester University, West Chester, Pennsylvania 19383 (United States)
2014-04-28
Boron aluminum hydride clusters are studied through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations. Boron aluminum hydride cluster anions, B{sub x}Al{sub y}H{sub z}{sup −}, were generated in a pulsed arc cluster ionization source and identified by time-of-flight mass spectrometry. After mass selection, their photoelectron spectra were measured by a magnetic bottle-type electron energy analyzer. The resultant photoelectron spectra as well as calculations on a selected series of stoichiometries reveal significant geometrical changes upon substitution of aluminum atoms by boron atoms.
6. Synthesis and Hydrogen Desorption Properties of Aluminum Hydrides.
Science.gov (United States)
Jeong, Wanseop; Lee, Sang-Hwa; Kim, Jaeyong
2016-03-01
Aluminum hydride (AlH3 or alane) is known to store maximum 10.1 wt.% of hydrogen at relatively low temperature (hydrogen desorption are still not clear. To understand the desorption properties of hydrogen in alane, thermodynamically stable α-AlH3 was synthesized by employing an ethereal reaction method. The dependence of pathways on phase formation and the properties of hydrogen evolution were investigated, and the results were compared with the ones for γ-AlH3. It was found that γ-AlH3 requires 10 degrees C higher than that of γ-AlH3 to form, and its decomposition rate demonstrated enhanced endothermic stabilities. For desorption, all hydrogen atoms of alane evolved under an isothermal condition at 138 degrees C in less than 1 hour, and the sample completely transformed to pure aluminum. Our results show that the total amount of desorbed hydrogen from α-AlH3 exceeded 9.05 wt.%, with a possibility of further increase. Easy synthesis, thermal stability, and a large amount of hydrogen desorption of alane fulfill the requirements for light-weight hydrogen storage materials once the pathway of hydrogen cycling is provided.
7. Synthesis of Renewable Energy Materials, Sodium Aluminum Hydride by Grignard Reagent of Al
OpenAIRE
Jun-qin Wang; Jian-feng Gao; Zhi-gang Wu; Guo-li Ou; Yu Wang
2015-01-01
The research on hydrogen generation and application has attracted widespread attention around the world. This paper is to demonstrate that sodium aluminum hydride can be synthesized under simple and mild reaction condition. Being activated through organics, aluminum powder reacts with hydrogen and sodium hydride to produce sodium aluminum hydride under atmospheric pressure. The properties and composition of the sample were characterized by FTIR, XRD, SEM, and so forth. The results showed that...
8. Synthesis of Renewable Energy Materials, Sodium Aluminum Hydride by Grignard Reagent of Al
Directory of Open Access Journals (Sweden)
Jun-qin Wang
2015-01-01
Full Text Available The research on hydrogen generation and application has attracted widespread attention around the world. This paper is to demonstrate that sodium aluminum hydride can be synthesized under simple and mild reaction condition. Being activated through organics, aluminum powder reacts with hydrogen and sodium hydride to produce sodium aluminum hydride under atmospheric pressure. The properties and composition of the sample were characterized by FTIR, XRD, SEM, and so forth. The results showed that the product through this synthesis method is sodium aluminum hydride, and it has higher purity, perfect crystal character, better stability, and good hydrogen storage property. The reaction mechanism is also discussed in detail.
9. Aluminum-titanium hydride-boron carbide composite provides lightweight neutron shield material
Science.gov (United States)
Poindexter, A. M.
1967-01-01
Inexpensive lightweight neutron shield material has high strength and ductility and withstands high internal heat generation rates without excessive thermal stress. This composite material combines structural and thermal properties of aluminum, neutron moderating properties of titanium hydride, and neutron absorbing characteristics of boron carbide.
10. Aluminum hydride as a hydrogen and energy storage material: Past, present and future
International Nuclear Information System (INIS)
Aluminum hydride (AlH3) and its associated compounds make up a fascinating class of materials that have motivated considerable scientific and technological research over the past 50 years. Due primarily to its high energy density, AlH3 has become a promising hydrogen and energy storage material that has been used (or proposed for use) as a rocket fuel, explosive, reducing agent and as a hydrogen source for portable fuel cells. This review covers the past, present and future research on aluminum hydride and includes the latest research developments on the synthesis of α-AlH3 and the other polymorphs (e.g., microcrystallization reaction, batch and continuous methods), crystallographic structures, thermodynamics and kinetics (e.g., as a function of crystallite size, catalysts and surface coatings), high-pressure hydrogenation experiments and possible regeneration routes.
11. Micro-scale fracture experiments on zirconium hydrides and phase boundaries
Science.gov (United States)
Chan, H.; Roberts, S. G.; Gong, J.
2016-07-01
Fracture properties of micro-scale zirconium hydrides and phase boundaries were studied using microcantilever testing methods. FIB-machined microcantilevers were milled on cross-sectional surfaces of hydrided samples, with the most highly-stressed regions within the δ-hydride film, within the α-Zr or along the Zr-hydride interface. Cantilevers were notched using the FIB and then tested in bending using a nanoindenter. Load-displacement results show that three types of cantilevers have distinct deformation properties. Zr cantilevers deformed plastically. Hydride cantilevers fractured after a small amount of plastic flow; the fracture toughness of the δ-hydride was found to be 3.3 ± 0.4 MPam1/2 and SEM examination showed transgranular cleavage on the fracture surfaces. Cantilevers notched at the Zr-hydride interface developed interfacial voids during loading, at loads considerably lower than that which initiate brittle fracture of hydrides.
12. Gallium Nitride Nanowires Grown by Hydride Vapor Phase Epitaxy
Institute of Scientific and Technical Information of China (English)
LIU Zhan-Hui; XIU Xiang-Qan; YAN Huai-Yue; ZHANG Rong; XIE Zi-Li; HAN Ping; SHI Yi; ZHENG You-Dou
2011-01-01
@@ GaN nanowires are grown by hydride vapor phase epitaxy using nickel as a catalyst.The properties of the obtained GaN nanowires are characterized by scanning and transmission electron microscopy,electron diffraction,roomtemperature photoluminescence and energy dispersive spectroscopy.The results show that the nanowires are wurtzite single crystals growing along the[0001]direction and a redshift in the photoluminescence is observed due to a superposition of several effects.The Raman spectra are close to those of the bulk GaN and the significantly broadening of those modes indicates the phonon confinement effects associated with the nanoscale dimensions of the system.%GaN nanowires are grown by hydride vapor phase epitaxy using nickel as a catalyst. The properties of the obtained GaN nanowires are characterized by scanning and transmission electron microscopy, electron diffraction, room-temperature photoluminescence and energy dispersive spectroscopy. The results show that the nanowires are wurtzite single crystals growing along the [0001] direction and a redshift in the photoluminescence is observed due to a superposition of several effects. The Raman spectra are close to those of the bulk GaN and the significantly broadening of those modes indicates the phonon confinement effects associated with the nanoscale dimensions of the system.
13. Crystal structure of the superconducting phase of sulfur hydride
Science.gov (United States)
Einaga, Mari; Sakata, Masafumi; Ishikawa, Takahiro; Shimizu, Katsuya; Eremets, Mikhail I.; Drozdov, Alexander P.; Troyan, Ivan A.; Hirao, Naohisa; Ohishi, Yasuo
2016-09-01
A superconducting critical temperature above 200 K has recently been discovered in H2S (or D2S) under high hydrostatic pressure. These measurements were interpreted in terms of a decomposition of these materials into elemental sulfur and a hydrogen-rich hydride that is responsible for the superconductivity, although direct experimental evidence for this mechanism has so far been lacking. Here we report the crystal structure of the superconducting phase of hydrogen sulfide (and deuterium sulfide) in the normal and superconducting states obtained by means of synchrotron X-ray diffraction measurements, combined with electrical resistance measurements at both room and low temperatures. We find that the superconducting phase is mostly in good agreement with the theoretically predicted body-centred cubic (bcc) structure for H3S. The presence of elemental sulfur is also manifest in the X-ray diffraction patterns, thus proving the decomposition mechanism of H2S to H3S + S under pressure.
14. Well-Defined Silica Supported Aluminum Hydride: Another Step Towards the Utopian Single Site Dream?
KAUST Repository
Werghi, Baraa
2015-07-17
Reaction of triisobutylaluminum with SBA15700 at room temperature occurs by two parallel pathways involving either silanol or siloxane bridges. It leads to the formation of a well-defined bipodal [(≡SiO)2Al-CH2CH(CH3)2] 1a, silicon isobutyl [≡Si-CH2CH(CH3)2] 1b and a silicon hydride [≡Si-H] 1c. Their structural identity was characterized by FT-IR and advance solid-state NMR spectroscopies (1H, 13C, 29Si, 27Al and 2D multiple quantum), elemental and gas phase analysis, and DFT calculations. The reaction involves the formation of a highly reactive monopodal intermediate: [≡SiO-Al-[CH2CH(CH3)2]2], with evolution of isobutane. This intermediate undergoes two parallel routes: Transfer of either one isobutyl fragment or of one hydride to an adjacent silicon atom. Both processes occur by opening of a strained siloxane bridge, ≡Si-O-Si≡ but with two different mechanisms, showing that the reality of “single site” catalyst may be an utopia: DFT calculations indicate that isobutyl transfer occurs via a simple metathesis between the Al-isobutyl and O-Si bonds, while hydride transfer occurs via a two steps mechanism, the first one is a ß-H elimination to Al with elimination of isobutene, whereas the second is a metathesis step between the formed Al-H bond and a O-Si bond. Thermal treatment of 1a (at 250 °C) under high vacuum (10-5 mbar) generates Al-H through a ß-H elimination of isobutyl fragment. These supported well-defined Al-H which are highly stable with time, are tetra, penta and octa coordinated as demonstrated by IR and 27Al–1H J-HMQC NMR spectroscopy. All these observations indicate that surfaces atoms around the site of grafting play a considerable role in the reactivity of a single site system.
15. A quantitative phase field model for hydride precipitation in zirconium alloys: Part I. Development of quantitative free energy functional
International Nuclear Information System (INIS)
A temperature dependent, quantitative free energy functional was developed for the modeling of hydride precipitation in zirconium alloys within a phase field scheme. The model takes into account crystallographic variants of hydrides, interfacial energy between hydride and matrix, interfacial energy between hydrides, elastoplastic hydride precipitation and interaction with externally applied stress. The model is fully quantitative in real time and real length scale, and simulation results were compared with limited experimental data available in the literature with a reasonable agreement. The work calls for experimental and/or theoretical investigations of some of the key material properties that are not yet available in the literature
16. Lightweight hydride storage materials
Energy Technology Data Exchange (ETDEWEB)
Thomas, G.J.; Guthrie, S.E.; Bauer, W. [Sandia National Labs., Livermore, CA (United States)
1995-09-01
The need for lightweight hydrides in vehicular applications has prompted considerable research into the use of magnesium and its alloys. Although this earlier work has provided some improved performance in operating temperature and pressure, substantial improvements are needed before these materials will significantly enhance the performance of an engineered system on a vehicle. We are extending the work of previous investigators on Mg alloys to reduce the operating temperature and hydride heat of formation in light weight materials. Two important results will be discussed in this paper: (1) a promising new alloy hydride was found which has better pressure-temperature characteristics than any previous Mg alloy and, (2) a new fabrication process for existing Mg alloys was developed and demonstrated. The new alloy hydride is composed of magnesium, aluminum and nickel. It has an equilibrium hydrogen overpressure of 1.3 atm. at 200{degrees}C and a storage capacity between 3 and 4 wt.% hydrogen. A hydrogen release rate of approximately 5 x 10{sup -4} moles-H{sub 2}/gm-min was measured at 200{degrees}C. The hydride heat of formation was found to be 13.5 - 14 kcal/mole-H{sub 2}, somewhat lower than Mg{sub 2}Ni. The new fabrication method takes advantage of the high vapor transport of magnesium. It was found that Mg{sub 2}Ni produced by our low temperature process was better than conventional materials because it was single phase (no Mg phase) and could be fabricated with very small particle sizes. Hydride measurements on this material showed faster kinetic response than conventional material. The technique could potentially be applied to in-situ hydride bed fabrication with improved packing density, release kinetics, thermal properties and mechanical stability.
17. Spray Forming Aluminum - Final Report (Phase II)
Energy Technology Data Exchange (ETDEWEB)
D. D. Leon
1999-07-08
The U.S. Department of Energy - Office of Industrial Technology (DOE) has an objective to increase energy efficient and enhance competitiveness of American metals industries. To support this objective, ALCOA Inc. entered into a cooperative program to develop spray forming technology for aluminum. This Phase II of the DOE Spray Forming Program would translate bench scale spray forming technology into a cost effective world class process for commercialization. Developments under DOE Cooperative Agreement No. DE-FC07-94ID13238 occurred during two time periods due to budgetary constraints; April 1994 through September 1996 and October 1997 and December 1998. During these periods, ALCOA Inc developed a linear spray forming nozzle and specific support processes capable of scale-up for commercial production of aluminum sheet alloy products. Emphasis was given to alloys 3003 and 6111, both being commercially significant alloys used in the automotive industry. The report reviews research performed in the following areas: Nozzel Development, Fabrication, Deposition, Metal Characterization, Computer Simulation and Economics. With the formation of a Holding Company, all intellectual property developed in Phases I and II of the Project have been documented under separate cover for licensing to domestic producers.
18. New nanomaterials for hydrogen storage. A new class of aluminum hydrides; Neue Nanomaterialien zur Wasserstoffspeicherung. Eine neue Klasse von Aluminiumhydriden
Energy Technology Data Exchange (ETDEWEB)
Cordes, Joern
2009-02-13
19. Possible "Magnéli" Phases and Self-Alloying in the Superconducting Sulfur Hydride
Science.gov (United States)
Akashi, Ryosuke; Sano, Wataru; Arita, Ryotaro; Tsuneyuki, Shinji
2016-08-01
We theoretically give an infinite number of metastable crystal structures for the superconducting sulfur hydride HxS under pressure. Previously predicted crystalline phases of H2S and H3S have been thought to have important roles for experimentally observed low and high Tc, respectively. The newly found structures are long-period modulated crystals where slablike H2S and H3S regions intergrow on a microscopic scale. The extremely small formation enthalpy for the H2S -H3S boundary indicated by first-principles calculations suggests possible alloying of these phases through the formation of local H3S regions. The modulated structures and gradual alloying transformations between them not only explain the peculiar pressure dependence of Tc in sulfur hydride observed experimentally, but also could prevail in the experimental samples under various compression schemes.
20. Heat capacity and magnetic phase diagram of the hydride CeRuSiH
Energy Technology Data Exchange (ETDEWEB)
Fernandez, J RodrIguez; Rojas, D P [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Gaudin, E; Chevalier, B, E-mail: rodrigufj@unican.es [CNRS, Universit de Bordeaux, ICMCB, 87 Avenue Dr. A. Schweitzer, 33608 Pessac (France)
2011-01-01
The hydride CeRuSiH exhibits antiferromagnetic order with two transitions at T{sub N1} = 7.5 and T{sub N2} = 3.1 K. Furthermore, magnetization measurements M (H) up to H = 45 kOe shows a metamagnetic double transition at low temperatures, suggesting a complex magnetic phase diagram. Here, we present magnetization measurements and heat capacity data up to 90 kOe, which allows as to complete the magnetic phase diagram. In addition, from the analysis of the heat capacity, we propose a model for the crystal field splitting.
1. Multiphysics phase field modeling of hydrogen diffusion and delta-hydride precipitation in alpha-zirconium
Science.gov (United States)
Jokisaari, Andrea M.
Hydride precipitation in zirconium is a significant factor limiting the lifetime of nuclear fuel cladding, because hydride microstructures play a key role in the degradation of fuel cladding. However, the behavior of hydrogen in zirconium has typically been modeled using mean field approaches, which do not consider microstructural evolution. This thesis describes a quantitative microstructural evolution model for the alpha-zirconium/delta-hydride system and the associated numerical methods and algorithms that were developed. The multiphysics, phase field-based model incorporates CALPHAD free energy descriptions, linear elastic solid mechanics, and classical nucleation theory. A flexible simulation software implementing the model, Hyrax, is built on the Multiphysics Object Oriented Simulation Environment (MOOSE) finite element framework. Hyrax is open-source and freely available; moreover, the numerical methods and algorithms that have been developed are generalizable to other systems. The algorithms are described in detail, and verification studies for each are discussed. In addition, analyses of the sensitivity of the simulation results to the choice of numerical parameters are presented. For example, threshold values for the CALPHAD free energy algorithm and the use of mesh and time adaptivity when employing the nucleation algorithm are studied. Furthermore, preliminary insights into the nucleation behavior of delta-hydrides are described. These include a) the sensitivities of the nucleation rate to temperature, interfacial energy, composition and elastic energy, b) the spatial variation of the nucleation rate around a single precipitate, and c) the effect of interfacial energy and nucleation rate on the precipitate microstructure. Finally, several avenues for future work are discussed. Topics encompass the terminal solid solubility hysteresis of hydrogen in zirconium and the effects of the alpha/delta interfacial energy, as well as thermodiffusion, plasticity
2. Stable High-Energy Density Super-Atom Clusters of Aluminum Hydride
Institute of Scientific and Technical Information of China (English)
Ke-yan Lian; Yuan-fei Jiang; De-hou Fei; Wei Feng; Ming-xing Jin; Da-jun Ding; Yi Luo
2012-01-01
With the concept of super-atom,first principles calculations propose a new type of super stable cage clusters AlnH3n that are much more energetic stable than the well established clusters,AlnHn+2.In the new clusters,the aluminum core-frame acts as a super-atom with n vertexes and 2n Al-Al edges,which allow to adsorb n hydrogen atoms at the top-site and 2n at the bridge-site.Using Al12H36 as the basic unit,stable chain structures,(Al12H36)m,have been constructed following the same connection mechanism as for (AlH3)n linear polymeric structures.Apart from high hydrogen percentage per molecule,calculations have shown that these new clusters possess large heat of formation values and their combustion heat is about 4.8 times of the methane,making them a promising high energy density material.
3. Verification and Validation Strategy for Implementation of Hybrid Potts-Phase Field Hydride Modeling Capability in MBM
Energy Technology Data Exchange (ETDEWEB)
Jason D. Hales; Veena Tikare
2014-04-01
The Used Fuel Disposition (UFD) program has initiated a project to develop a hydride formation modeling tool using a hybrid Pottsphase field approach. The Potts model is incorporated in the SPPARKS code from Sandia National Laboratories. The phase field model is provided through MARMOT from Idaho National Laboratory.
4. Influence of the V/III ratio in the gas phase on thin epitaxial AlN layers grown on (0001) sapphire by high temperature hydride vapor phase epitaxy
Energy Technology Data Exchange (ETDEWEB)
Claudel, A., E-mail: arnaud.claudel@grenoble-inp.org [ACERDE, 354 Voie Magellan — Alpespace, 73800 Ste Hélène du Lac (France); Fellmann, V. [ACERDE, 354 Voie Magellan — Alpespace, 73800 Ste Hélène du Lac (France); Science et Ingénierie des Matériaux et des Procédés, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Hères (France); Gélard, I. [ACERDE, 354 Voie Magellan — Alpespace, 73800 Ste Hélène du Lac (France); Coudurier, N. [ACERDE, 354 Voie Magellan — Alpespace, 73800 Ste Hélène du Lac (France); Science et Ingénierie des Matériaux et des Procédés, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Hères (France); Sauvage, D. [ACERDE, 354 Voie Magellan — Alpespace, 73800 Ste Hélène du Lac (France); Balaji, M. [ACERDE, 354 Voie Magellan — Alpespace, 73800 Ste Hélène du Lac (France); Science et Ingénierie des Matériaux et des Procédés, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Hères (France); Crystal Growth Center, Anna University, Chennai 600025 (India); and others
2014-12-31
Thin (0001) epitaxial aluminum nitride (AlN) layers were grown on c-plane sapphire using high temperature hydride vapor phase epitaxy. The experimental set-up consists of a vertical cold-wall quartz reactor working at low pressure in which the reactions take place on a susceptor heated by induction. The reactants used are ammonia and aluminum chlorides in situ formed via hydrogen chloride reaction with high purity aluminum pellets. As-grown AlN layers have been characterized by scanning electron microscopy, atomic force microscopy, X-ray diffraction, transmission electron microscopy, photoluminescence and Raman spectroscopies. The influence of the V/III ratio in the gas phase, from 1.5 to 15, on growth rate, surface morphology, roughness and crystalline quality is investigated in order to increase the quality of thin epitaxial AlN layers grown at high temperature. Typical growth rates of around 0.45 μm/h were obtained for such thin epitaxial AlN layers. The growth rate was unaffected by the V/III ratio. An optimum for roughness, crystalline quality and optical properties seems to exist at V/III = 7.5. As a matter of fact, for a V/III ratio of 7.5, best root mean square roughness and crystalline quality — measured on 0002 symmetric reflection — as low as 6.9 nm and 898 arcsec were obtained, respectively. - Highlights: • Growth of thin epitaxial AlN layers by high temperature hydride vapor phase epitaxy • Influence of V/III ratio on growth rate, morphology and crystalline quality • The effect of surface morphology on strain state and crystal quality is established.
5. Chemical Liquid Phase Deposition of Thin Aluminum Oxide Films
OpenAIRE
Sun, Jie; Sun, Yingchun
2007-01-01
Thin aluminum oxide films were deposited by a new and simple physicochemical method called chemical liquid phase deposition (CLD) on semiconductor materials. Aluminum sulfate with crystallized water and sodium bicarbonate were used as precursors for film growth, and the control of the system pH value played an important role in this experiment. The growth rate is 12 nm/h at room temperature. Post-growth annealing not only densifies and purifies the films, but results in film crystallization a...
6. Ab initio study of H and He migrations in β-phase Sc, Y, and Er hydrides
Institute of Scientific and Technical Information of China (English)
Chen Ru-Cheng; Yang Li; Dai Yun-Ya; Zhu Zi-Qiang; Peng Shu-Ming; Long Xing-Gui; Gao Fei; Zu Xiao-Tao
2012-01-01
Ab initio calculations based on the density functional theory have been performed to investigate the migrations of hydrogen(H)and helium(He)atoms in β-phase scandium(Sc),yttrium(Y),and erbium(Er)hydrides with three different ratios of H to metal.The results show that the migration mechanisms of H and He atoms mainly depend on the crystal structures of hydrides,but their energy barriers are affected by the host-lattice in metal hydrides.The formation energies of octahedral-occupancy H(Hoct)and tetrahedral vacancy(Vtet)pairs are almost the same(about 1.2 eV).It is of interest to note that the migration barriers of H increase with increasing host-lattice atomic number.In addition,the results show that the favorable migration mechanism of He depends slightly on the Vtet in the Sc hydride,but strongly on that in the Y and Er hydrides,which may account for different behaviours of initial He release from ScT2 and ErT2.
7. Luminescence transients in highly excited GaN grown by hydride vapor-phase epitaxy
Energy Technology Data Exchange (ETDEWEB)
Jursenas, S.; Miasojedovas, S.; Kurilcik, G.; Zukauskas, A. [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-2040 Vilnius (Lithuania); Hageman, P.R. [University of Nijmegen, Fac. of Science, Dept. of Exp. Solid State Physics III, Toernooiveld 1, 6525 ED Nijmegen (Netherlands)
2004-01-01
Luminescence transients has been studied in GaN grown by hydride vapor-phase epitaxy (HVPE) under intense photoexcitation conditions. The HVPE grown GaN layer exhibited luminescence decay time of 205 ps, that implies the room-temperature free-carrier lifetime of 420 ps. The obtained carrier lifetime of HVPE-grown GaN is significantly higher that the typical values of carrier lifetime measured for GaN heterolayers grown by metalorganic chemical vapor deposition, what suggests high potential of HVPE growth technique for light-emitting diode and blue laser applications. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
8. Electrical, optical, and structural properties of GaN films prepared by hydride vapor phase epitaxy
International Nuclear Information System (INIS)
Highlights: • GaN films are prepared by hydride vapor phase epitaxy (HVPE). • Residual donors and deep traps show a minimum density versus growth temperature. • This minimum is located close to the HVPE growth temperature of 950 °C. • Good crystalline GaN with residual donor density < 1016 cm−3 can be grown at 950 °C. - Abstract: Two sets of undoped GaN films with the thickness of 10–20 μm were prepared by hydride vapor phase epitaxy (HVPE) and characterized by capacitance–voltage (C–V) profiling, microcathodoluminescence (MCL) spectra measurements, MCL imaging, electron beam induced current (EBIC) imaging, EBIC dependence on accelerating voltage, deep levels transient spectroscopy, high resolution X-ray diffraction measurements. The difference in growth conditions was mainly related to the lower (850 °C, group 1) or higher (950 °C, group 2) growth temperature. Both groups of samples showed similar crystalline quality with the dislocation density close to 108 cm−2, but very different electrical and optical properties. In group 1 samples the residual donors concentration was ∼1017 cm−3 or higher, the MCL spectra were dominated by the band-edge luminescence, and the diffusion length of charge carriers was close to 0.1 μm. Group 2 samples had a 2–4.5 μm thick highly resistive layer on top, for which MCL spectra were determined by green, yellow and red defect bands, and the diffusion length was 1.5 times higher than in group 1. We also present brief results of growth at the “standard” HVPE growth temperature of 1050 °C that show the presence of a minimum in the net donor concentration and deep traps density as a function of the growth temperature. Possible reasons for the observed results are discussed in terms of the electrical compensation of residual donors by deep traps
9. Hangzhou Jinjiang Group Shanxi Fusheng Aluminum Phase I 800,000 t/a Aluminum Oxide Project Started Operation
Institute of Scientific and Technical Information of China (English)
2014-01-01
<正>On October 19,the Shanxi Province Pinglu County Phase I 800,000t/a Aluminum Oxide Project of Shanxi Fusheng Aluminum Co.,Ltd,a subordinate of Hangzhou Jinjiang Group,started operation.This is the fourth Aluminum oxide project constructed and operated by Jinjiang Group.
10. Point defect dynamics in sodium aluminum hydrides - a combined quasielastic neutron scattering and density functional theory study
DEFF Research Database (Denmark)
Shi, Qing; Voss, Johannes; Jacobsen, H.S.;
2007-01-01
Understanding the catalytic role of titanium-based additives on the reversible hydrogenation of complex metal hydrides is an essential step towards developing hydrogen storage materials for the transport sector. Improved bulk diffusion of hydrogen is one of the proposed catalytic effects, and here...
11. Clean Grain Boundary Found in C14/Body-Center-Cubic Multi-Phase Metal Hydride Alloys
Directory of Open Access Journals (Sweden)
Hao-Ting Shen
2016-06-01
Full Text Available The grain boundaries of three Laves phase-related body-center-cubic (bcc solid-solution, metal hydride (MH alloys with different phase abundances were closely examined by scanning electron microscopy (SEM, transmission electron microscopy (TEM, and more importantly, electron backscatter diffraction (EBSD techniques. By using EBSD, we were able to identify the alignment of the crystallographic orientations of the three major phases in the alloys (C14, bcc, and B2 structures. This finding confirms the presence of crystallographically sharp interfaces between neighboring phases, which is a basic assumption for synergetic effects in a multi-phase MH system.
12. Hysteresis in Metal Hydrides.
Science.gov (United States)
Flanagan, Ted B., And Others
1987-01-01
This paper describes a reproducible process where the irreversibility can be readily evaluated and provides a thermodynamic description of the important phenomenon of hysteresis. A metal hydride is used because hysteresis is observed during the formation and decomposition of the hydride phase. (RH)
13. Electrical, optical, and structural properties of GaN films prepared by hydride vapor phase epitaxy
Energy Technology Data Exchange (ETDEWEB)
Polyakov, A.Y. [National University of Science and Technology MISiS, Moscow (Russian Federation); School of Advanced Materials Engineering and Research Center of Advanced Materials Development, Chonbuk National University, Jeonju (Korea, Republic of); Smirnov, N.B. [National University of Science and Technology MISiS, Moscow (Russian Federation); Institute of Rare Metals, Moscow (Russian Federation); Yakimov, E.B. [Institute of Microelectronics Technology and High Purity Materials Russian Academy of Science, Chernogolovka (Russian Federation); Usikov, A.S. [Nitride Crystals, Inc., Deer Park (United States); Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, Saint Petersburg (Russian Federation); Helava, H. [Nitride Crystals, Inc., Deer Park (United States); Shcherbachev, K.D. [School of Advanced Materials Engineering and Research Center of Advanced Materials Development, Chonbuk National University, Jeonju (Korea, Republic of); Govorkov, A.V. [Institute of Rare Metals, Moscow (Russian Federation); Makarov, Yu N. [Nitride Crystals, Inc., Deer Park (United States); Lee, In-Hwan, E-mail: ihlee@jbnu.ac.kr [School of Advanced Materials Engineering and Research Center of Advanced Materials Development, Chonbuk National University, Jeonju (Korea, Republic of)
2014-12-25
Highlights: • GaN films are prepared by hydride vapor phase epitaxy (HVPE). • Residual donors and deep traps show a minimum density versus growth temperature. • This minimum is located close to the HVPE growth temperature of 950 °C. • Good crystalline GaN with residual donor density < 10{sup 16} cm{sup −3} can be grown at 950 °C. - Abstract: Two sets of undoped GaN films with the thickness of 10–20 μm were prepared by hydride vapor phase epitaxy (HVPE) and characterized by capacitance–voltage (C–V) profiling, microcathodoluminescence (MCL) spectra measurements, MCL imaging, electron beam induced current (EBIC) imaging, EBIC dependence on accelerating voltage, deep levels transient spectroscopy, high resolution X-ray diffraction measurements. The difference in growth conditions was mainly related to the lower (850 °C, group 1) or higher (950 °C, group 2) growth temperature. Both groups of samples showed similar crystalline quality with the dislocation density close to 10{sup 8} cm{sup −2}, but very different electrical and optical properties. In group 1 samples the residual donors concentration was ∼10{sup 17} cm{sup −3} or higher, the MCL spectra were dominated by the band-edge luminescence, and the diffusion length of charge carriers was close to 0.1 μm. Group 2 samples had a 2–4.5 μm thick highly resistive layer on top, for which MCL spectra were determined by green, yellow and red defect bands, and the diffusion length was 1.5 times higher than in group 1. We also present brief results of growth at the “standard” HVPE growth temperature of 1050 °C that show the presence of a minimum in the net donor concentration and deep traps density as a function of the growth temperature. Possible reasons for the observed results are discussed in terms of the electrical compensation of residual donors by deep traps.
14. Determination of arsenic and selenium by hydride generation and headspace solid phase microextraction coupled with optical emission spectrometry
Energy Technology Data Exchange (ETDEWEB)
Tyburska, Anna; Jankowski, Krzysztof, E-mail: kj@ch.pw.edu.pl; Rodzik, Agnieszka
2011-07-15
A hydride generation headspace solid phase microextraction technique has been developed in combination with optical emission spectrometry for determination of total arsenic and selenium. Hydrides were generated in a 10 mL volume septum-sealed vial and subsequently collected onto a polydimethylsiloxane/Carboxen solid phase microextraction fiber from the headspace of sample solution. After completion of the sorption, the fiber was transferred into a thermal desorption unit and the analytes were vaporized and directly introduced into argon inductively coupled plasma or helium microwave induced plasma radiation source. Experimental conditions of hydride formation reaction as well as sorption and desorption of analytes have been optimized showing the significant effect of the type of the solid phase microextraction fiber coating, the sorption time and hydrochloric acid concentration of the sample solution on analytical characteristics of the method developed. The limits of detection of arsenic and selenium were 0.1 and 0.8 ng mL{sup -1}, respectively. The limit of detection of selenium could be improved further using biosorption with baker's yeast Saccharomyces cerevisiae for analyte preconcentration. The technique was applied for the determination of total As and Se in real samples.
15. Identification of Si and O donors in hydride-vapor-phase epitaxial GaN
Science.gov (United States)
Moore, W. J.; Freitas, J. A.; Braga, G. C. B.; Molnar, R. J.; Lee, S. K.; Lee, K. Y.; Song, I. J.
2001-10-01
Donor impurity excitation spectra in the infrared from two high-quality, not-intentionally doped, hydride-vapor-phase epitaxial GaN wafers are reported. Two previously observed shallow donors which we designate N1 and N2 were observed in both wafers. However, spectra of one wafer are dominated by N1 and spectra of the other by N2. A comparison of infrared and secondary ion mass spectroscopic data allows identification of N1 as Si and N2 as O. Silicon is the shallowest uncompensated donor in these samples with an activation energy of 30.18±0.1 meV in the freestanding Samsung wafer. The activation energy of O is found to be 33.20±0.1 meV. An unidentified third donor with an activation energy of 31.23±0.1 meV also was observed. Integrated absorption cross sections are found to be 8.5×10-14 cm for Si and 8.6×10-14 cm for O.
16. Epitaxial growth of three dimensionally structured III-V photonic crystal via hydride vapor phase epitaxy
International Nuclear Information System (INIS)
Three-dimensional (3D) photonic crystals are one class of materials where epitaxy, and the resultant attractive electronic properties, would enable new functionalities for optoelectronic devices. Here we utilize self-assembled colloidal templates to fabricate epitaxially grown single crystal 3D mesostructured GaxIn1−xP (GaInP) semiconductor photonic crystals using hydride vapor phase epitaxy (HVPE). The epitaxial relationship between the 3D GaInP and the substrate is preserved during the growth through the complex geometry of the template as confirmed by X-ray diffraction (XRD) and high resolution transmission electron microscopy. XRD reciprocal space mapping of the 3D epitaxial layer further demonstrates the film to be nearly fully relaxed with a negligible strain gradient. Fourier transform infrared spectroscopy reflection measurement indicates the optical properties of the photonic crystal which agree with finite difference time domain simulations. This work extends the scope of the very few known methods for the fabrication of epitaxial III-V 3D mesostructured materials to the well-developed HVPE technique
17. Gradual variation method for thick GaN heteroepitaxy by hydride vapour phase epitaxy
Institute of Scientific and Technical Information of China (English)
Du Yan-Hao; Wu Jie-Jun; Luo Wei-Ke; John Goldsmith; Han Tong; Tao Yue-Bin; Yang Zhi-Jian; Yu Tong-Jun; Zhang Guo-Yi
2011-01-01
Two strain-state samples of GaN,labelled the strain-relief sample and the quality-improved sample,were grown by hydride vapour phase epitaxy (HVPE),and then characterized by high-resolution X-ray diffraction,photoluminescence and optical microscopy. Two strain states of GaN in HVPE,like 3D and 2D growth modes in metal-organic chemical vapour deposition (MOCVD),provide an effective way to solve the heteroepitaxial problems of both strain relief and quality improvement. The gradual variation method (GVM),developed based on the two strain states,is characterized by growth parameters' gradual variation alternating between the strain-relief growth conditions and the qualityimproved growth conditions. In GVM,the introduction of the strain-relief amplitude,which is defined by the range from the quality-improved growth conditions to the strain-relief growth conditions,makes the strain-relief control concise and effective. The 300-4m thick bright and crack-free GaN film grown on a two-inch sapphire proves the effectiveness of GVM.
18. Epitaxial growth of three dimensionally structured III-V photonic crystal via hydride vapor phase epitaxy
Energy Technology Data Exchange (ETDEWEB)
Zheng, Qiye; Kim, Honggyu; Zhang, Runyu; Zuo, Jianmin; Braun, Paul V., E-mail: pbraun@illinois.edu [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Sardela, Mauro [Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Balaji, Manavaimaran; Lourdudoss, Sebastian; Sun, Yan-Ting [Laboratory of Semiconductor Materials, Department of Materials and Nano Physics, Royal Institute of Technology (KTH), Electrum 229, 164 40 Kista (Sweden)
2015-12-14
Three-dimensional (3D) photonic crystals are one class of materials where epitaxy, and the resultant attractive electronic properties, would enable new functionalities for optoelectronic devices. Here we utilize self-assembled colloidal templates to fabricate epitaxially grown single crystal 3D mesostructured Ga{sub x}In{sub 1−x}P (GaInP) semiconductor photonic crystals using hydride vapor phase epitaxy (HVPE). The epitaxial relationship between the 3D GaInP and the substrate is preserved during the growth through the complex geometry of the template as confirmed by X-ray diffraction (XRD) and high resolution transmission electron microscopy. XRD reciprocal space mapping of the 3D epitaxial layer further demonstrates the film to be nearly fully relaxed with a negligible strain gradient. Fourier transform infrared spectroscopy reflection measurement indicates the optical properties of the photonic crystal which agree with finite difference time domain simulations. This work extends the scope of the very few known methods for the fabrication of epitaxial III-V 3D mesostructured materials to the well-developed HVPE technique.
19. Nucleation of GaN on sapphire substrates at intermediate temperatures by Hydride Vapor Phase Epitaxy
Energy Technology Data Exchange (ETDEWEB)
Lukin, G.; Niederschlag, E.; Paetzold, O.; Stelter, M. [Institute of Nonferrous Metallurgy and Purest Materials, TU Bergakademie Freiberg (Germany); Roeder, C.; Kortus, J. [Institute of Theoretical Physics, TU Bergakademie Freiberg (Germany); Shashev, Y.; Muehle, U.; Rafaja, D. [Institute of Materials Science, TU Bergakademie Freiberg (Germany)
2012-02-15
A novel approach to deposit GaN layers directly on a sapphire substrate by Hydride Vapor Phase Epitaxy is presented. The two-step deposition process includes the growth of GaN nucleation layers at intermediate temperatures in the range of 750 - 900 C and subsequent high-temperature overgrowth at about 1040 C. Closed and non-closed nucleation layers with a thickness of up to 2 {mu}m were produced and characterized by scanning and transmission electron microscopy, micro-Raman spectroscopy and X-ray diffraction. A growth temperature of 780 C is found to be optimal with respect to density and size distribution of nucleation islands. Raman measurements performed on the nucleation layers reveal nearly zero residual stress indicating effective stress relaxation on cooling down from growth temperature. The results of first overgrowth experiments demonstrate the possibility to grow 10 {mu}m thick, crack-free GaN layers of high crystalline quality on the nucleation layers. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
20. Computational fluid dynamics-aided analysis of a hydride vapor phase epitaxy reactor
Science.gov (United States)
Schulte, Kevin L.; Simon, John; Roy, Abhra; Reedy, Robert C.; Young, David L.; Kuech, Thomas F.; Ptak, Aaron J.
2016-01-01
We report the development of a computational fluid dynamics (CFD) model of a dual chamber hydride vapor phase epitaxial (HVPE) growth reactor. Uniformity of reactant concentrations in the growth stream, transient reactor flows, and cross doping between the two growth chambers, all factors critical to the deposition of uniform, low defect semiconductor layers, were modeled. Simulation results were generated by solving the fundamental continuity, momentum and energy equations over a discretized reactor volume by a finite volume analysis with the aid of CFD-ACE+ commercial software. We demonstrated uniformity of the vapor composition within ±1% across the substrate, achieved due to specific features of the reactor design. Small compositional non-uniformity (±2% absolute) in In1-xGaxP layers grown in our reactor was correlated with calculated temperature non-uniformity across the substrate. Gas switching was modeled and the transient time predicted by the model was confirmed by measurement of doping transients in a sample grown in the reactor. Lastly the gas curtains that chemically isolate the reactor chambers were modeled and the results were compared to experimental data for cross doping between the chambers. As an example, we demonstrate, based on insight from the model, that our HVPE reactor is suitable for the deposition of GaAs PV devices. CFD modeling is a critical tool for the scale up of laboratory level processes to industrial levels.
1. Planarization and Processing of Metamorphic Buffer Layers Grown by Hydride Vapor-Phase Epitaxy
Science.gov (United States)
Zutter, Brian T.; Schulte, Kevin L.; Kim, Tae Wan; Mawst, Luke J.; Kuech, T. F.; Foran, Brendan; Sin, Yongkun
2014-04-01
Hydride vapor-phase epitaxy (HVPE) is a high-growth-rate, cost-effective means to grow epitaxial semiconductor material. Thick HVPE-based metamorphic buffer layers (MBLs) can serve as "pseudosubstrates" with controllable lattice parameter. In our structures, the indium content in In x Ga1- x As is gradually increased from zero to the final composition corresponding to the desired lattice constant, and then a thick (˜10 μm) constant-composition capping layer is grown. This thick capping layer promotes maximum strain relaxation while permitting use of polishing procedures to achieve surface planarity. Lattice-mismatched growth of MBLs invariably results in rough, cross-hatched surface morphology exhibiting up to 200 nm peak-to-valley roughness. This roughness can be eliminated by chemical mechanical planarization, thus creating a suitable surface for subsequent regrowth. Polishing of In x Ga1- x As is complicated by the sensitivity of the surface layer to the polishing parameters, particularly the applied pressure. Polishing at high applied pressure (12 psi) results in the formation of circular asperities hundreds of nanometers high and tens of microns in diameter. When lower applied pressure (4 psi) was used, the cross-hatching height of MBLs was lowered from 200 nm to <10 nm over a 350 μm lateral scale. The successfully planarized In0.20Ga0.80As MBLs were used as a substrate for a superlattice (SL) structure such as that used in quantum cascade lasers. Use of planarization before regrowth of the SL resulted in a reduction of the high-resolution x-ray diffraction peak full-width at half-maximum from 389″ to 159″.
2. Polycrystalline indium phosphide on silicon by indium assisted growth in hydride vapor phase epitaxy
Energy Technology Data Exchange (ETDEWEB)
Metaferia, Wondwosen; Sun, Yan-Ting, E-mail: yasun@kth.se; Lourdudoss, Sebastian [Laboratory of Semiconductor Materials, Department of Materials and Nano Physics, KTH—Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Pietralunga, Silvia M. [CNR-Institute for Photonics and Nanotechnologies, P. Leonardo da Vinci, 32 20133 Milano (Italy); Zani, Maurizio; Tagliaferri, Alberto [Department of Physics Politecnico di Milano, P. Leonardo da Vinci, 32 20133 Milano (Italy)
2014-07-21
Polycrystalline InP was grown on Si(001) and Si(111) substrates by using indium (In) metal as a starting material in hydride vapor phase epitaxy (HVPE) reactor. In metal was deposited on silicon substrates by thermal evaporation technique. The deposited In resulted in islands of different size and was found to be polycrystalline in nature. Different growth experiments of growing InP were performed, and the growth mechanism was investigated. Atomic force microscopy and scanning electron microscopy for morphological investigation, Scanning Auger microscopy for surface and compositional analyses, powder X-ray diffraction for crystallinity, and micro photoluminescence for optical quality assessment were conducted. It is shown that the growth starts first by phosphidisation of the In islands to InP followed by subsequent selective deposition of InP in HVPE regardless of the Si substrate orientation. Polycrystalline InP of large grain size is achieved and the growth rate as high as 21 μm/h is obtained on both substrates. Sulfur doping of the polycrystalline InP was investigated by growing alternating layers of sulfur doped and unintentionally doped InP for equal interval of time. These layers could be delineated by stain etching showing that enough amount of sulfur can be incorporated. Grains of large lateral dimension up to 3 μm polycrystalline InP on Si with good morphological and optical quality is obtained. The process is generic and it can also be applied for the growth of other polycrystalline III–V semiconductor layers on low cost and flexible substrates for solar cell applications.
3. Chemical Liquid Phase Deposition of Thin Aluminum Oxide Films
Institute of Scientific and Technical Information of China (English)
SUN,Jie(孙捷); SUN,Ying-Chun(孙迎春)
2004-01-01
Thin aluminum oxide films were deposited by a new and simple physicochemical method called chemical liquid phase deposition (CLD) on semiconductor materials. Aluminum sulfate with crystallized water and sodium bicarbonate were used as precursors for film growth, and the control of the system's pH value played an important role in this experiment. The growth rate is 12 nm/h with the deposition at [Al2(SO4)3]=0.0837 mol·L-1, [NaHCO3]=0.214 mol·L-1, 15 ℃. Post-growth annealing not only densifies and purifies the films, but results in film crystallization as well, Excellent quality of A12O3 films in this work is supported by electron dispersion spectroscopy,Fourier transform infrared spectrum, X-ray diffraction spectrum and scanning electron microscopy photograph.
4. A New Reducing Regent: Dichloroindium Hydride
Institute of Scientific and Technical Information of China (English)
A. BABA; I. SHIBATA; N. HAYASHI
2005-01-01
@@ 1Introduction Among the hydride derivatives of group 13 elements, various types of aluminum hydrides and boron hydrides have been employed as powerful reduction tools. Indium hydrides have not received much attention,whereas the synthesis of indium trihydride (InH3) was reported several decades ago[1]. There have been no precedents for monometallic indium hydrides having practical reactivity, while activated hydrides such as an ate complex LiPhn InH4-n (n = 0- 2) and phosphine-coordinated indium hydrides readily reduce carbonyl compounds. In view of this background, we focused on the development of dichloroindium hydrides (Cl2InH) as novel reducing agents that bear characteristic features in both ionic and radical reactions.
5. First Principles Studies of Phase Stability and Reaction Dynamics in Complex Metal Hydrides
Energy Technology Data Exchange (ETDEWEB)
Chou, Mei-Yin
2014-09-29
Complex metal hydrides are believed to be one of the most promising materials for developing hydrogen storage systems that can operate under desirable conditions. At the same time, these are also a class of materials that exhibit intriguing properties. We have used state-of-the-art computational techniques to study the fundamental properties of these materials.
6. Effect of Reactor Pressure on Qualities of GaN Layers Grown by Hydride Vapour Phase Eqitaxy
Institute of Scientific and Technical Information of China (English)
QIU Kai; WANG Yu-Qi; YIN Zhi-Jun; LI Xin-Hua; ZHONG Fei; JI Chang-Jian; HAN Qi-Feng; CAO Xian-cun; CHEN Jia-Rong; LUO Xiang-Dong
2007-01-01
The influence of reactor pressure on GaN layers grown by hydride vapour phase epitaxy (HVPE) is investigated. By decreasing the reactor pressure from 0.7 to 0.5atm,he GaN layer growth mode changes from the island-like one to the step flow. The improvements in structural and optical properties and surface morphology of GaN layers are observed in the step now growth mode. The results clearly indicate that the reactor pressure, similarly to the growth temperature, is one of the important parameters to influence the qualities of GaN epilayers grown by HVPE, due to the change of growth mode.
7. Flow analysis-hydride generation-gas phase derivative molecular absorption spectrophotometric determination of antimony in antileishmanial drugs
Directory of Open Access Journals (Sweden)
Máximo Gallignani
2009-01-01
Full Text Available In the present work, the development of a method based on the coupling of flow analysis (FA, hydride generation (HG, and derivative molecular absorption spectrophotometry (D-EAM in gas phase (GP, is described in order to determine total antimony in antileishmanial products. Second derivative order (D²224nm of the absorption spectrum (190 - 300 nm is utilized as measurement criterion. Each one of the parameters involved in the development of the proposed method was examined and optimized. The utilization of the EAM in GP as detection system in a continuous mode instead of atomic absorption spectrometry represents the great potential of the analytic proposal.
8. Guangxi Shanglin Aluminum Plant cross-regional technical upgrade project(phase 1)put into operation
Institute of Scientific and Technical Information of China (English)
2007-01-01
<正>The project(Phase 1)of cross-regional techni- cal upgrade of the aluminum plant of Guangxi Shanglin Nannan Industrial Co.was completed and put into operation on June 8,2007.The plant is a cross-regional technical upgrade pro- ject of Nanning Aluminum Plant,featuring the integration of coal,electricity and aluminum.
9. YNi and its hydrides: Phase stabilities, electronic structures and chemical bonding properties from first principles
Energy Technology Data Exchange (ETDEWEB)
Matar, S.F., E-mail: matar@icmcb-bordeaux.cnrs.fr [CNRS, Universite de Bordeaux, ICMCB, 87 avenue du Docteur Albert Schweitzer, F-33608 Pessac (France); Nakhl, M. [Universite Libanaise, Laboratoire de Chimie-Physique des Materiaux LCPM, Fanar (Lebanon); Al Alam, A.F.; Ouaini, N. [Universite Saint-Esprit de Kaslik, Faculte des Sciences et de Genie Informatique, Jounieh (Lebanon); Chevalier, B. [CNRS, Universite de Bordeaux, ICMCB, 87 avenue du Docteur Albert Schweitzer, F-33608 Pessac (France)
2010-11-25
Graphical abstract: Base centered orthorhombic YNiH{sub X} structure. For x = 3, only H1 and H2 are present. Highest hydrogen content YNiH{sub 4} is obtained when H3 are added. - Abstract: Within density functional theory, establishing the equations of states of YNi in two different controversial structures in the literature, leads to determine the orthorhombic FeB-type as the ground state one with small energy difference. For YNiH{sub 3} and YNiH{sub 4} hydrides crystallizing in the orthorhombic CrB-type structure the geometry optimization and the ab initio determination of the H atomic positions show that the stability of hydrogen decreases from the tri- to the tetra- hydride. New states brought by hydrogen within the valence band lead to its broadening and to enhanced localization of metal density of states. The chemical bonding analysis shows a preferential Ni-H bonding versus Y-H.
10. Ca2LiC3H: a new complex carbide hydride phase grown in metal flux.
Science.gov (United States)
Lang, David A; Zaikina, Julia V; Lovingood, Derek D; Gedris, Thomas E; Latturner, Susan E
2010-12-15
The reaction of carbon and CaH2 in a calcium/lithium flux mixture produces crystals of the new compound Ca2LiC3H. This phase forms with a new structure type in tetragonal space group P4/mbm (a = 6.8236(1) Å, c = 3.7518(1) Å, Z = 2, R1 = 0.0151). This is a stuffed variant of the Cs2(NH2)N3 structure, containing hydride anions in octahedral sites; the structure determination by single-crystal X-ray diffraction surprisingly allowed the hydrogen to be detected. The Ca2LiC3H structure also features the rarely seen C3(4-) carbide anion; the protolysis reaction of this compound with ammonium chloride produces C3H4. The electronic properties of Ca2LiC3H were studied by quantum-chemical calculations including band structure and electron localization function (ELF) analysis; the phase is a charge-balanced semiconductor with a calculated band gap of 0.48 eV. This is in agreement with (7)Li, (13)C, and (1)H MAS NMR data, which show resonances in the ionic region instead of the Knight shifted region. ELF analysis of the theoretical nonhydrided Ca2LiC3 structure confirms the ability of these calculations to properly locate hydrides and supports the structural model based on X-ray diffraction data.
11. Gas-Phase Combustion Synthesis of Aluminum Nitride Powder
Science.gov (United States)
Axelbaum, R. L.; Lottes, C. R.; Huertas, J. I.; Rosen, L. J.
1996-01-01
Due to its combined properties of high electrical resistivity and high thermal conductivity aluminum nitride (AlN) is a highly desirable material for electronics applications. Methods are being sought for synthesis of unagglomerated, nanometer-sized powders of this material, prepared in such a way that they can be consolidated into solid compacts having minimal oxygen content. A procedure for synthesizing these powders through gas-phase combustion is described. This novel approach involves reacting AlCl3, NH3, and Na vapors. Equilibrium thermodynamic calculations show that 100% yields can be obtained for these reactants with the products being AlN, NaCl, and H2. The NaCl by-product is used to coat the AlN particles in situ. The coating allows for control of AlN agglomeration and protects the powders from hydrolysis during post-flame handling. On the basis of thermodynamic and kinetic considerations, two different approaches were employed to produce the powder, in co-flow diffusion flame configurations. In the first approach, the three reactants were supplied in separate streams. In the second, the AlCl3 and NH3 were premixed with HCl and then reacted with Na vapor. X-ray diffraction (XRD) spectra of as-produced powders show only NaCl for the first case and NaCl and AlN for the second. After annealing at 775 C tinder dynamic vacuum, the salt was removed and XRD spectra of powders from both approaches show only AlN. Aluminum metal was also produced in the co-flow flame by reacting AlCl3 with Na. XRD spectra of as-produced powders show the products to be only NaCl and elemental aluminum.
12. Interstellar Hydrides
CERN Document Server
Gerin, Maryvonne; Goicoechea, Javier R
2016-01-01
Interstellar hydrides -- that is, molecules containing a single heavy element atom with one or more hydrogen atoms -- were among the first molecules detected outside the solar system. They lie at the root of interstellar chemistry, being among the first species to form in initially-atomic gas, along with molecular hydrogen and its associated ions. Because the chemical pathways leading to the formation of interstellar hydrides are relatively simple, the analysis of the observed abundances is relatively straightforward and provides key information about the environments where hydrides are found. Recent years have seen rapid progress in our understanding of interstellar hydrides, thanks largely to far-IR and submillimeter observations performed with the Herschel Space Observatory. In this review, we will discuss observations of interstellar hydrides, along with the advanced modeling approaches that have been used to interpret them, and the unique information that has thereby been obtained.
13. Metal hydride/chemical heat-pump development project, phase 1
Science.gov (United States)
Argabright, T. A.
1982-02-01
The metal hydride/chemical heat pump (MHHP) is a chemical heat pump containing two hydrides for the storage and/or recovery of thermal energy. It utilizes the heat of reaction of hydrogen with specific metal alloys. The MHHP design can be tailored to provide heating and/or cooling or temperature upgrading over a wide range of input and ambient temperatures. The system can thus be used with a variety of heat sources including waste heat, solar energy or a fossil fuel. The conceptual design of the MHHP was developed. A national market survey including a study of applications and market sectors was conducted. The technical tasks including conceptual development, thermal and mechanical design, laboratory verification of design and material performance, cost analysis and the detailed design of the Engineering Development Test Unit (EDTU) were performed. As a result of the market study, the temperature upgrade cycle of the MHHP was chosen for development. Operating temperature ranges for the upgrader were selected to be from 70 to 1100 C (160 to 2300 F) for the source heat and 140 to 1900 C (280 to 3750 F) for the product heat.
14. Superconductivity and the structural phase transitions in palladium hydride and palladium deuteride
International Nuclear Information System (INIS)
The results of two experimental studies of the superconducting transition temperature, T/sub c/, of palladium hydride, PdH/sub x/, and palladium deuteride, PdD/sub x/, are presented. In the first study, the superconducting transition temperature of PdH/sub x/(D/sub x/) is studied as a function of H(D) concentration, x, in the temperature range from 0.2 K to 4K. The data join smoothly with those reported previously by Miller and Satterthwaite at higher temperatures, and the composite data are described by the empirical relation T/sub c/ = 150.8 (x-x/sub o/)2244, where x/sub o/ = 0.715 for hydride samples and 0.668 for deuteride samples. The results, when compared with the theoretical predictions of Klein and Papaconstantopoulos, et al., raise questions about the validity of their explanation of the reverse isotope effect, which is based solely on a difference in force constants. In the second study, the effect of the order-disorder structural transition associated with the 50 K anomaly on the superconductivity of PdH/sub x/(D/sub x/) is investigated. Samples were quenched to low temperatures in the disordered state, and their transition temperatures measured. The samples were then annealed just below the anomaly temperature, and the ordering process followed by monitoring the change in sample resistance. The transition temperatures in the ordered state were then measured
15. Hydrogen, lithium, and lithium hydride production
Science.gov (United States)
Brown, Sam W; Spencer, Larry S; Phillips, Michael R; Powell, G. Louis; Campbell, Peggy J
2014-03-25
A method of producing high purity lithium metal is provided, where gaseous-phase lithium metal is extracted from lithium hydride and condensed to form solid high purity lithium metal. The high purity lithium metal may be hydrided to provide high purity lithium hydride.
16. Effect of vapor phase corrosion inhibitor on microbial corrosion of aluminum alloys.
Science.gov (United States)
Yang, S S; Ku, C H; Bor, H J; Lin, Y T
1996-02-01
Vapor phase corrosion inhibitors were used to investigate the antimicrobial activities and anticorrosion of aluminum alloy. Aspergillus flavus, A. niger, A. versicolor, Chaetomium globosum and Penicillium funiculosum had moderate to abundant growth on the aluminum alloy AA 1100 at Aw 0.901, while there was less growth at Aw 0.842. High humidity stimulated microbial growth and induced microbial corrosion. Dicyclohexylammonium carbonate had a high inhibitory effect on the growth of test fungi and the microbial corrosion of aluminum alloy, dicyclohexylammonium caprate and dicyclohexylammonium stearate were the next. Aluminum alloy coating with vapor phase corrosion inhibitor could prevent microbial growth and retard microbial corrosion. PMID:10592784
17. Effect of AlN intermediate layer on growing GaN film by hydride vapor phase epitaxy
Institute of Scientific and Technical Information of China (English)
LIN Chaotong; RUTERANA Pierre; CHEN Jun; YU Guanghui; LEI Benliang; WANG Xinzhong; YE Haohua; MENG Sheng; QI Ming; LI Aizhen; NOUET Gérard
2006-01-01
Thick GaN layer deposited by hydride vapor phase epitaxy (HVPE) on a metalorganic chemical vapor deposition (MOCVD) GaN template with a thin low temperature (LT) AlN intermediate layer was investigated.High resolution X-ray resolution diffraction (HRXRD) shows that the crystalline quality of thick GaN layer was improved compared with the template.As confirmed by atomic force microscopy (AFM) observations, the surface morphology of AlN intermediate layer helps to improve the nucleation of GaN epilayer.Photoluminescence (PL) spectra measurement shows its high optical quality and low compressive stress, and micro Raman measurement confirms the latter result.Thus, the deposition of the LT-AlN interlayer has promoted the growth of an HVPE-GaN layer with an excellent crystalline quality.
18. Properties of GaN on different polarity buffer layers by hydride vapour phase epitaxy
Institute of Scientific and Technical Information of China (English)
Qiu Kai; Zhong Fei; Li Xin-Hua; Yin Zhi-Jun; Ji Chang-Jian; Han Qi-Feng; Chen Jia-Rong; Cao Xian-Cun; Wang Yu-Qi
2007-01-01
This paper reports on N-, mixed-, and Ga-polarity buffer layers are grown by molecular beam epitaxy (MBE) on sapphire (0001) substrates, with the GaN thicker films grown on the buffer layer with different polarity by hydride vapour epitaxy technique (HVPE). The surface morphology, structural and optical properties of these HVPF-GaN epilayers are characterized by wet chemical etching, scanning electron microscope, x-ray diffraction, and photoluminescence spectrum respectively. It finds that the N-polarity film is unstable against the higher growth temperature and wet chemical etching,while that of GaN polarity one is stable. The results indicate that the crystalline quality of HVPE-GaN epilayers depends on the polarity of buffer layers.
19. Hydride Generation for Headspace Solid-Phase Extraction with CdTe Quantum Dots Immobilized on Paper for Sensitive Visual Detection of Selenium.
Science.gov (United States)
Huang, Ke; Xu, Kailai; Zhu, Wei; Yang, Lu; Hou, Xiandeng; Zheng, Chengbin
2016-01-01
A low-cost, simple, and highly selective analytical method was developed for sensitive visual detection of selenium in human urine both outdoors and at home, by coupling hydride generation with headspace solid-phase extraction using quantum dots (QDs) immobilized on paper. The visible fluorescence from the CdTe QDs immobilized on paper was quenched by H2Se from hydride generation reaction and headspace solid-phase extraction. The potential mechanism was investigated by using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) as well as Density Functional Theory (DFT). Potential interferences from coexisting ions, particularly Ag(+), Cu(2+), and Zn(2+), were eliminated. The selectivity was significantly increased because the selenium hydride was effectively separated from sample matrices by hydride generation. Moreover, due to the high sampling efficiency of hydride generation and headspace solid phase extraction, the sensitivity and the limit of detection (LOD) were significantly improved compared to conventional methods. A LOD of 0.1 μg L(-1) and a relative standard deviation (RSD, n = 7) of 2.4% at a concentration of 20 μg L(-1) were obtained when using a commercial spectrofluorometer as the detector. Furthermore, a visual assay based on the proposed method was developed for the detection of Se, 5 μg L(-1) of selenium in urine can be discriminated from the blank solution with the naked eye. The proposed method was validated by analysis of certified reference materials and human urine samples with satisfactory results. PMID:26631425
20. Prediction of the zeta potentials and ionic descriptors of a silica hydride stationary phase with mobile phases of different pH and ionic strength.
Science.gov (United States)
Kulsing, Chadin; Yang, Yuanzhong; Matyska, Maria T; Pesek, Joseph J; Boysen, Reinhard I; Hearn, Milton T W
2015-02-15
In this study, the zeta potentials of a silica hydride stationary phase (Diamond Hydride™) in the presence of different water-acetonitrile mixtures (from 0-80% (v/v) acetonitrile) of different ionic strengths (from 0-40mM) and pH values (from pH 3.0-7.0) have been investigated. Debye-Hückel theory was applied to explain the effect of changes in the pH and ionic strength of these aqueous media on the negative zeta potential of this stationary phase. The experimental zeta potentials of the Diamond Hydride™ particles as a function of acetonitrile content up to 50% (v/v) correlated (R(2)=0.998) with the predicted zeta potential values based on this established theory, when the values of the dissociation constant of all related species, as well as viscosity, dielectric constant and refractive index of the aqueous medium were taken into consideration. Further, the retention behavior of basic, acidic and neutral analytes was investigated under mobile phase conditions of higher pH and lower ionic strength. Under these conditions, the Diamond Hydride™ stationary phase surface became more negative, as assessed from the increasingly more negative zeta potentials, resulting in the ion exchange characteristics becoming more dominant and the basic analytes showing increasing retention. Ionic descriptors were derived from these chromatographic experiments based on the assumption that linear solvation energy relationships prevail. The results were compared with predicted ionic descriptors based on the different calculated zeta potential values resulting in an overall correlation of R(2)=0.888. These studies provide fundamental insights into the impact on the separation performance of changes in the zeta potential of the Diamond Hydride™ surface with the results relevant to other silica hydride and, potentially, to other types of stationary phase materials.
1. Determination of trace selenium in high purity tellurium by hydride generation atomic fluorescence spectrometry after solid phase extraction of a diaminobenzidine-selenium chelate
Science.gov (United States)
Tong, Wang; Ying, Zeng; Jinyong, Xu
2016-09-01
Macroporous adsorption resin was used as the sorbent for solid phase extraction and determination of the trace Se content in high purity tellurium prior to hydride generation atomic fluorescence spectrometry analysis. Selenium was converted into an organic Se chelate using 3,3‧-diaminobenzidine and was separated from the tellurium matrix by solid phase extraction. The resin was packed as a column for solid phase extraction. Under optimum conditions, trace Se can be quantitatively extracted and the tellurium matrix can be removed. The Se in the eluate was determined by hydride generation atomic fluorescence spectrometry. The limit of detection (3σ) of this method was 0.22 ng g- 1 and the relative standard deviation (RSD, n = 5) ranged from 2.0 to 2.5% for the three investigated tellurium samples. The proposed method was successfully applied for the determination of the trace Se content in high purity tellurium samples.
2. Crystallographic measurement of the β to α phase transformation and δ-hydride precipitation in a laser-welded Zircaloy-2 tube by electron backscattering diffraction
International Nuclear Information System (INIS)
Crystallographic measurement of the β to α phase transformation and δ-hydride precipitation in a laser-welded Zircaloy-2 ferrule tube were carried out using an electron backscattering diffraction pattern (EBSP). A basket-weave structure with sub-micron lath width caused by quenching from the β to α phase was observed in the heat-affected and fusion zones, and mainly showed a grain boundary misorientation angle of 60 deg. with an rotation axis. This result is consistent with the Burgers orientation relationship of {1 1 0}β//(0 0 0 1)α and β//α for the β to α phase transformation. The texture of the quenched α' phase was strongly inherited from the original α phase, having a radial (0 0 0 1) basal pole and axial {1 1 2-bar0} textures, even in the fusion zone. The primary hydride habit plane in the welded Zircaloy-2 was (0 0 0 1)α//{1 1 1}δ, matching previously obtained results for recrystallized cladding tubes. In addition to the primary habit plane, secondary habit planes were observed for the other low-index planes {1 0 1-bar0} and {1 0 1-bar1} in the fusion zone. The heterogeneous accumulation of hydrides in the transition zone between heat-affected and unaffected zones was mainly due to the residual stress distribution in the narrow region.
3. Crystallographic measurement of the β to α phase transformation and δ-hydride precipitation in a laser-welded Zircaloy-2 tube by electron backscattering diffraction
Science.gov (United States)
Une, K.; Ishimoto, S.
2009-06-01
Crystallographic measurement of the β to α phase transformation and δ-hydride precipitation in a laser-welded Zircaloy-2 ferrule tube were carried out using an electron backscattering diffraction pattern (EBSP). A basket-weave structure with sub-micron lath width caused by quenching from the β to α phase was observed in the heat-affected and fusion zones, and mainly showed a grain boundary misorientation angle of 60° with an rotation axis. This result is consistent with the Burgers orientation relationship of {1 1 0} β//(0 0 0 1) α and β// α for the β to α phase transformation. The texture of the quenched α' phase was strongly inherited from the original α phase, having a radial (0 0 0 1) basal pole and axial {1 1 2¯ 0} textures, even in the fusion zone. The primary hydride habit plane in the welded Zircaloy-2 was (0 0 0 1) α//{1 1 1} δ, matching previously obtained results for recrystallized cladding tubes. In addition to the primary habit plane, secondary habit planes were observed for the other low-index planes {1 0 1¯ 0} and {1 0 1¯ 1} in the fusion zone. The heterogeneous accumulation of hydrides in the transition zone between heat-affected and unaffected zones was mainly due to the residual stress distribution in the narrow region.
4. Precipitation and Deposition of Aluminum-Containing Phases in Tank Wastes
International Nuclear Information System (INIS)
Aluminum-containing phases compose the bulk of solids precipitating during the processing of radioactive tank wastes. Processes designed to minimize the volume of high-level waste through conversion to glassy phases require transporting waste solutions near-saturated with aluminum-containing species from holding tank to processing center. The uncontrolled precipitation within transfer lines results in clogged pipes and lines and fouled ion exchangers, with the potential to shut down processing operations
5. Precipitation and Deposition of Aluminum-Containing Phases in Tank Wastes
Energy Technology Data Exchange (ETDEWEB)
Daniel M. Dabbs; Ilhan A. Aksay
2005-01-12
Aluminum-containing phases compose the bulk of solids precipitating during the processing of radioactive tank wastes. Processes designed to minimize the volume of high-level waste through conversion to glassy phases require transporting waste solutions near-saturated with aluminum-containing species from holding tank to processing center. The uncontrolled precipitation within transfer lines results in clogged pipes and lines and fouled ion exchangers, with the potential to shut down processing operations.
6. Density functional theory study on LaNi4.5Al0.5 hydride phase: electronic properties and sites occupation
Institute of Scientific and Technical Information of China (English)
Chen Dong; Yu Ben-Hai; Wang Chun-Lei; Gao Tao
2007-01-01
In this paper the crystal structure, electronic structure and hydrogen site occupation of LaNi4.5Al0.5Hy hydride phase (y=5.0, 6.0) have been investigated by using full-potential linearized augmented plane wave method. The hydrogen atoms were found to prefer the 6m, 12o and 12n sites, while no 4h sites were occupied. A narrowed Ni-d band is found due to the lattice expansion, the total density of states at EF increases with y, which indicates that the compounds become less stable. The interaction between Al and Ni, H plays a dominant role in the stability of LaNi4.sAl0.5Hy hydride phase. The smaller the shift of EF towards the higher energy region, the more stable the compounds will be. The obtained results are compared with experimental data and discussed in the light of previous works.
7. Theoretical Study of Hydrogenated Tetrahedral Aluminum Clusters
CERN Document Server
Ichikawa, Kazuhide; Wagatsuma, Ayumu; Watanabe, Kouhei; Szarek, Pawel; Tachibana, Akitomo
2011-01-01
We report on the structures of aluminum hydrides derived from a tetrahedral aluminum Al4 cluster using ab initio quantum chemical calculation. Our calculation of binding energies of the aluminum hydrides reveals that stability of these hydrides increases as more hydrogen atoms are adsorbed, while stability of Al-H bonds decreases. We also analyze and discuss the chemical bonds of those clusters by using recently developed method based on the electronic stress tensor.
8. Preparation of Porous GaN Buffer and Its Influence on the Residual Stress of GaN Epilayers Grown by Hydride Vapor Phase Epitaxy
Institute of Scientific and Technical Information of China (English)
2007-01-01
The preparation of porous structure on the molecular beam epitaxy (MBE)-grown mixed-polarity GaN epilayers was reported by using the wet chemical etching method. The effect of this porous structure on the residual stress of subsequent-growth GaN epilayers was studied by Raman and photoluminescence (PL) spectrum.Substantial decrease in the biaxial stresse can be achieved by employing the porous buffers in the hydride vapour phase epitaxy (HVPE) epilayer growth.
9. Photo-electrochemical etching of free-standing GaN wafer surfaces grown by hydride vapor phase epitaxy
International Nuclear Information System (INIS)
An investigation into the photo-electrochemical (PEC) etching of free-standing GaN wafers produced by hydride vapor phase epitaxial growth (HVPE) has found that etching is only possible with UV illumination in an acidic or basic electrolyte. Through photo-current measurement and X-ray analysis it was determined that lack of etching in a neutral electrolyte can be attributed to the formation of an oxide film on the GaN surface. Surface damage was also found to be a significant factor, with the etching rate and photo current density of surfaces treated by grinding and mechanical polishing being markedly less compared to a finely polished surface. Subsequent investigation of the luminescence and the etching characteristics of the intentionally-introduced scratches indicated that subsurface damage is difficult to remove from GaN by PEC etching due to the trapping of photo-excited carriers. A peculiar surface feature of concentric ring structures made up of alternating small and large pores was observed on the GaN surface along with small island regions, which is attributed to variations in the electronic properties of the GaN crystal that is created during HVPE growth
10. Hydride development for hydrogen storage
Energy Technology Data Exchange (ETDEWEB)
Thomas, G.J.; Guthrie, S.E.; Bauer, W.; Yang, N.Y.C. [Sandia National Lab., Livermore, CA (United States); Sandrock, G. [SunaTech, Inc., Ringwood, NJ (United States)
1996-10-01
The purpose of this project is to develop and demonstrate improved hydride materials for hydrogen storage. The work currently is organized into four tasks: hydride development, bed fabrication, materials support for engineering systems, and IEA Annex 12 activities. At the present time, hydride development is focused on Mg alloys. These materials generally have higher weight densities for storing hydrogen than rare earth or transition metal alloys, but suffer from high operating temperatures, slow kinetic behavior and material stability. The authors approach is to study bulk alloy additions which increase equilibrium overpressure, in combination with stable surface alloy modification and particle size control to improve kinetic properties. This work attempts to build on the considerable previous research in this area, but examines specific alloy systems in greater detail, with attention to known phase properties and structures. The authors have found that specific phases can be produced which have significantly improved hydride properties compared to previous studies.
11. Structural phase stability, electronic structure and mechanical properties of alkali metal hydrides AMH4 (A=Li, Na; M=B, AL)
Science.gov (United States)
Santhosh, M.; Rajeswarapalanichamy, R.
2016-01-01
The structural stability of Alkali metal hydrides AMH4 (A=Li, Na; M=B, Al) is analyzed among the various crystal structures, namely hexagonal (P63mc), tetragonal (P42/nmc), tetragonal (P-421c), tetragonal (I41/a), orthorhombic (Pnma) and monoclinic (P21/c). It is observed that, orthorhombic (Pnma) phase is the most stable structure for LiBH4, monoclinic (P21/c) for LiAlH4, tetragonal (P42/nmc) for NaBH4 and tetragonal (I41/a) for NaAlH4 at normal pressure. Pressure induced structural phase transitions are observed in LiBH4, LiAlH4, NaBH4 and NaAlH4 at the pressures of 4 GPa, 36.1 GPa, 26.5 GPa and 46 GPa respectively. The electronic structure reveals that these metal hydrides are wide band gap insulators. The calculated elastic constants indicate that these metal hydrides are mechanically stable at normal pressure.
12. Probing the cerium/cerium hydride interface using nanoindentation
Energy Technology Data Exchange (ETDEWEB)
Brierley, Martin, E-mail: martin.brierley@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom); University of Manchester, Manchester M13 9PL (United Kingdom); Knowles, John, E-mail: john.knowles@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom)
2015-10-05
Highlights: • A disparity exists between the minimum energy and actual shape of a cerium hydride. • Cerium hydride is found to be harder than cerium metal by a ratio of 1.7:1. • A zone of material under compressive stress was identified surrounding the hydride. • No distribution of hardness was apparent within the hydride. - Abstract: A cerium hydride site was sectioned and the mechanical properties of the exposed phases (cerium metal, cerium hydride, oxidised cerium hydride) were measured using nanoindentation. An interfacial region under compressive stress was observed in the cerium metal surrounding a surface hydride that formed as a consequence of strain energy generated by the volume expansion associated with precipitation of the hydride phase.
13. Probing the cerium/cerium hydride interface using nanoindentation
International Nuclear Information System (INIS)
Highlights: • A disparity exists between the minimum energy and actual shape of a cerium hydride. • Cerium hydride is found to be harder than cerium metal by a ratio of 1.7:1. • A zone of material under compressive stress was identified surrounding the hydride. • No distribution of hardness was apparent within the hydride. - Abstract: A cerium hydride site was sectioned and the mechanical properties of the exposed phases (cerium metal, cerium hydride, oxidised cerium hydride) were measured using nanoindentation. An interfacial region under compressive stress was observed in the cerium metal surrounding a surface hydride that formed as a consequence of strain energy generated by the volume expansion associated with precipitation of the hydride phase
14. Kinetics of hydride front in Zircaloy-2 and H release from a fractional hydrided surface
Energy Technology Data Exchange (ETDEWEB)
Diaz, M.; Gonzalez-Gonzalez, A.; Moya, J. S.; Remartinez, B.; Perez, S.; Sacedon, J. L. [Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain); Iberdrola, Tomas Redondo 3, 28033 Madrid (Spain); Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain)
2009-07-15
The authors study the hydriding process on commercial nuclear fuel claddings from their inner surface using an ultrahigh vacuum method. The method allows determining the incubation and failure times of the fuel claddings, as well as the dissipated energy and the partial pressure of the desorbed H{sub 2} from the outer surface of fuel claddings during the hydriding process. The correlation between the hydriding dissipated energy and the amount of zirconium hydride (formed at different stages of the hydriding process) leads to a near t{sup 1/2} potential law corresponding to the time scaling of the reaction for the majority of the tested samples. The calibrated relation between energy and hydride thickness allows one to calculate the enthalpy of the {delta}-ZrH{sub 1.5} phase. The measured H{sub 2} desorption from the external surface is in agreement with a proposed kinetic desorption model from the hydrides precipitated at the surface.
15. Formation of uniform magnetic structures and epitaxial hydride phases in Nd/Pr superlattices
DEFF Research Database (Denmark)
Goff, J.P.; Bryn-Jacobsen, C.; McMorrow, D.F.;
1997-01-01
The chemical and magnetic structures of neodymium/praseodymium superlattices grown by molecular-beam epitaxy have been determined using x-ray and neutron-diffraction techniques. The x-ray measurements show that the superlattices have a dhcp structure of high crystalline quality, and that the stac...... these light rare-earth samples are found to react with hydrogen to form new single-crystal phases, which are coherent with the epitaxial structure.......The chemical and magnetic structures of neodymium/praseodymium superlattices grown by molecular-beam epitaxy have been determined using x-ray and neutron-diffraction techniques. The x-ray measurements show that the superlattices have a dhcp structure of high crystalline quality......, and that the stacking sequence is coherent over many bilayer repeats. The neutron measurements show that for the hexagonal sites of the dhcp structure, the Nd magnetic order propagates coherently through the Pr, whereas the order on the cubic sites is either suppressed or confined to single Nd blocks. It is also shown...
16. Research on Metal Hydride Compressor System
Institute of Scientific and Technical Information of China (English)
1999-01-01
Ti-Zr series Laves phase hydrogen storage alloys with good hydrogen storage properties, such as large hydrogen capacity, rapid hydriding and dehydriding rate, high compression ratio, gentle plateau, small hysteresis, easily being activated and long cyclic stability etc. for metal hydride compressor have been investigated. In addition, a hydride compressor with special characteristics, namely, advanced filling method, good heat transfer effect and reasonable structural design etc. has also been constructed. A hydride compressor cryogenic system has been assembled coupling the compressor with a J-T micro-throttling refrigeration device and its cooling capacity can reach 0.4 W at 25 K.
17. Planar gas chromatography column on aluminum plate with multi-walled carbon nanotubes as stationary phase
Science.gov (United States)
Platonov, I. A.; Platonov, V. I.; Pavelyev, V. S.
2016-04-01
The high selectivity of the adsorption layer for low-boiling alkanes is shown, the separation factor (α) couple iso-butane / butane is 1.9 at a column temperature of 50 °C.The paper presents sorption and selective properties of planar gas chromatography column on aluminum plate with multi-walled carbon nanotubes as the stationary phase.
18. Guangxi Pingguo Aluminum Alumina 3rd Phase Project to Put Into Production
Institute of Scientific and Technical Information of China (English)
2008-01-01
<正>In April,the handover ceremony was held for the first completed sub-project of the 3rd phase of 900,000-ton alumina project of China Alu- minum Guangxi Company (Pingguo Aluminum in short),standing for the commencement of
19. Precipitation and Deposition of Aluminum-Containing Phases in Tank Wastes. Final Report
International Nuclear Information System (INIS)
Aluminum-containing phases compose the bulk of solids precipitating during the processing of radioactive tank wastes. Processes designed to minimize the volume of high-level waste through conversion to glassy phases require transporting waste solutions near-saturated with aluminum-containing species from holding tank to processing center. The uncontrolled precipitation within transfer lines results in clogged pipes and lines and fouled ion exchangers, with the potential to shut down processing operations. The principal focus of our research was to maintain the fluidity of aluminum- or silicon-containing suspensions and solutions during transport, whether by preventing particle formation, stabilizing colloidal particles in suspension, or by combining partial dissolution with particle stabilization. We have found that all of these can be effected in aluminum-containing solutions using the simple organic, citric acid. Silicon-containing solutions were found to be less tractable, but we have strong indications that chemistries similar to the citric acid/aluminum suspensions can be effective in maintaining silicon suspensions at high alkalinities. In the first phase of our study, we focused on the use of simple organics to raise the solubility of aluminum oxyhydroxides in high alkaline aqueous solvents. In a limited survey of common organic acids, we determined that citric acid had the highest potential to achieve our goal. However, our subsequent investigation revealed that the citric acid appeared to play two roles in the solutions: first, raising the concentration of aluminum in highly alkaline solutions by breaking up or inhibiting 'seed' polycations and thereby delaying the nucleation and growth of particles; and second, stabilizing nanometer-sized particles in suspension when nucleation did occur. The second phase of our work involved the solvation of silicon, again in solutions of high alkalinity. Here, the use of polyols was determined to be effective in
20. Catalyst-assisted hydride vapor phase epitaxy of GaN nanowires: exceptional length and constant rod-like shape capability
Science.gov (United States)
Lekhal, K.; Avit, G.; André, Y.; Trassoudaine, A.; Gil, E.; Varenne, C.; Bougerol, C.; Monier, G.; Castelluci, D.
2012-10-01
The hydride vapor phase epitaxy (HVPE) process exhibits unexpected properties when growing GaN semiconductor nanowires (NWs). With respect to the classical well-known methods such as metal organic vapor phase epitaxy and molecular beam epitaxy, this near-equilibrium process based on hot wall reactor technology enables the synthesis of nanowires with a constant cylinder shape over unusual length. Catalyst-assisted HVPE shows a record short time process (less than 20 min) coupled to very low precursor consumption. NWs are grown at a fast solidification rate (50 μm h-1), facilitated by the high decomposition frequency of the chloride molecules involved in the HVPE process as element III precursors. In this work growth temperature and V/III ratio were investigated to determine the growth mechanism which led to such long NWs. Analysis based on the Ni-Ga phase diagram and the growth kinetics of near-equilibrium HVPE is proposed.
1. Numerical and experimental study of phase transformation in resistance spot welding of 6082 aluminum alloy
Institute of Scientific and Technical Information of China (English)
TANG Xinxin; SHA Ping; LUO Zhen; LUO Baofa
2009-01-01
Resistance spot welding(RSW) is an efficient and convenient joining process for aluminum alloy sheet assembly. Because the RSW has the character of energy concentration and quick cooling rate, the microstructure transformation of the base metal can be confined in the least limit. The material properties and the welding parameters have significant effects on thequality of the nugget. To predict the microstructure evolution in the melted zone and the heat-affected zone, an electrical, thermal, metallurgical and mechanical coupled finite element model is described and applied to simulate the welding process of the 6082 aluminum alloy. Experimental tests are also carried out. The comparison between experimental and numerical results shows that the adopted model is effective enough to well interpret and predict some important phenomena in terms of the phase transformation in spot welding of 6082 aluminum alloy.
2. Electromagnetic separation of primary iron-rich phases from aluminum-silicon melt
Institute of Scientific and Technical Information of China (English)
李天晓; 许振明; 孙宝德; 疏达; 周尧和
2003-01-01
The difference of conductivity between primary iron-rich phases and aluminum melt has been used toseparate them by electromagnetic force (EMF) which is induced by imposing a direct electric current and a steadymagnetic field in molten Al-Si alloy. Theoretical analysis and experiments on self-designed electromagnetic separa-tion indicates that primary needle-like β phases are difficult to separate; while primary a iron-rich phases can be sepa-rated by electromagnetic separation. Primary iron-rich phases have been removed from the melt successfully whenthe molten metal flows horizontally through separation channel. The iron content is reduced from 1.13% to 0.41%.
3. Interface properties and phase formation between surface coated SKD61 and aluminum alloys
Institute of Scientific and Technical Information of China (English)
Se-Weon CHOI; Young-Chan KIM; Se-Hun CHANG; Ik-Hyun OH; Joon-Sik PARK; Chang-Seog KANG
2009-01-01
The intermediate phase formation and surface protection effects between SKD61 die mold alloys and aluminum alloys were investigated during a simulated die-casting process. The surface coatings of SKD61 alloy were carried out via Si pack cementation coatings at 900 ℃ for 10 h and the e-FeSi phase formed. When the coated SKD61 alloy was dipped in the liquid aluminum alloy (ALDC12), the surface coated SKD61 alloys showed better surface properties compared with uncoated SKD61 alloys, i.e., the intermediate phases (FeSiAl compound) were not produced for the coated SKD61 alloy. The coating layer of e-FeSi served as a diffusion barrier for the formation of FeSiAl compounds.
4. GaAs Solar Cells Grown by Hydride Vapor-Phase Epitaxy and the Development of GaInP Cladding Layers
Energy Technology Data Exchange (ETDEWEB)
Simon, John; Schulte, Kevin L.; Young, David L.; Haegel, Nancy M.; Ptak, Aaron J.
2016-01-01
The high cost of high-efficiency III-V photovoltaic devices currently limits them to niche markets. Hydride vapor-phase epitaxy (HVPE) growth of III-V materials recently reemerged as a low-cost, high-throughput alternative to conventional metal- organic vapor-phase epitaxy (MOVPE) growth of high-efficiency solar cells. Previously, we demonstrated unpassivated HVPEgrown GaAs p-n junctions with good quantum efficiency and high open-circuit voltage (Voc). In this work, we demonstrate the growth of GaInPby HVPE for use as a high-quality surface passivation layer to GaAs solar cells. Solar cells grown with GaInP window layers show significantly improved quantum efficiency compared with unpassivated cells, increasing the short-circuit current (JSC) of these low-cost devices. These results show the potential of low-cost HVPE for the growth of high-quality III-V devices.
5. Thick orientation-patterned growth of GaP on wafer-fused GaAs templates by hydride vapor phase epitaxy for frequency conversion
Science.gov (United States)
Vangala, Shivashankar; Kimani, Martin; Peterson, Rita; Stites, Ron; Snure, Michael; Tassev, Vladimir
2016-10-01
Quasi-phase-matched (QPM) GaP layers up to 300 μm thick have been produced by low-pressure hydride vapor phase epitaxy (LP-HVPE) overgrowth on orientation-patterned GaAs (OPGaAs) templates fabricated using a wafer-fusion bonding technique. The growth on the OPGaAs templates resulted in up to 200 μm thick vertically propagating domains, with a total GaP thickness of 300 μm. The successful thick growth on OPGaAs templates is the first step towards solving the material problems associated with unreliable material quality of commercially available GaP wafers and making the whole process of designing QPM frequency conversion devices molecular beam epitaxy free and more cost-effective.
6. Thermomechanical properties of hafnium hydride
International Nuclear Information System (INIS)
Fine bulk samples of delta-phase Hf hydride with various hydrogen contents (CH) ranging from 1.62 to 1.72 in the atomic ratio (H/Hf) were prepared, and their thermomechanical properties were characterized. At room temperature, the sound velocity and Vickers hardness were measured. The elastic modulus was calculated from the measured sound velocity. In the temperature range from room temperature to 673 K, the thermal expansion was measured by using a dilatometer, and the linear thermal expansion coefficient was calculated. Empirical equations describing the thermomechanical properties of Hf hydride as a function of CH were proposed. (author)
7. Comminution by hydriding-dehydriding process of the U-Zr-Nb alloys stabilized at different phases by aging heat treatment
Energy Technology Data Exchange (ETDEWEB)
Cantagalli, Natalia Mattar; Pais, Rafael Witter Dias; Braga, Daniel Martins; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa, E-mail: ferrazw@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG) Belo Horizonte, MG (Brazil)
2011-07-01
Powders of the U-Zr-Nb alloys are raw materials for obtaining plate-type dispersion fuel of high density and medium enrichment for research and test reactors as well as small power reactors. U-2.5Zr-7.5Nb and U-3Zr-9Nb (wt%) alloys, initially homogenized at high temperatures, were transformed at different phases by means aging heat treatments, and then comminuted by hydriding-dehydriding process to powder production. The phases transformations were obtained by the homogenization of the U-2.5Zr-7.5Nb and U-3Zr-9Nb alloys at high temperatures (1000 deg C for 1 and 16 h), followed by aging heat treatment at 600 deg C, in times of 0.5 h, 3.0 h and 24h, and subsequently quenched in water to stabilize the desired phase. The comminution process was performed at 200 deg C for different times ranging from 20 minutes to 4 hours. The powders were then characterized by scanning electron microscopy, X-ray diffraction and determination of particle size distribution by means of laser equipment CILAS. One of the main objectives of this study was to verify the influence of the different phases in the characteristics of the obtained powders. It was found that alloys stabilized in gamma phase produced powders with smaller particles sizes than those with cellular structure of the {alpha} and {gamma} phases. Regardless of retained phases, the produced powders consist of agglomerates with irregular morphology. (author)
8. Crystalline Phase and Decomposition Dynamics of Aluminum Titanate at Different Temperature
Institute of Scientific and Technical Information of China (English)
林寿; 阮玉忠; 沈阳; 罗金荣
2012-01-01
The crystalline phase formed during aluminum titanate at 750-1300 ℃ as well as the relationship between its content change and decomposition dynamics was mainly discussed in this paper.Dynamical equation was established for calculating the reaction activation energy.It aimed at providing dynamics basic data for taking up necessary measures to inhibit the decomposition of aluminum titanate.Experimental results showed that aluminum titanate would decompose into TiO2 and corundum at 750-1300 ℃.Content of aluminum titanate would reduce with the increase of decomposition time,and the order of decomposition rates at different temperature was 1100 1200 1000 900 ℃.The decomposition was a chemical reaction with control steps,and could meet the first order reaction dynamic equation-F（G） = [（1-G）-2/3-1] = Kt.According to the calculation,rate constants of different decomposition reaction dynamic equations were K900 = 2.2×10-3,K1000 = 1.2×10-2,K1100 = 4×10-1 and K1200 = 1.5×10-1,and the reaction activation energy ΔGave = 203.21 KJ/mol.
9. Cross-stacked carbon nanotubes assisted self-separation of free-standing GaN substrates by hydride vapor phase epitaxy
Science.gov (United States)
Wei, Tongbo; Yang, Jiankun; Wei, Yang; Huo, Ziqiang; Ji, Xiaoli; Zhang, Yun; Wang, Junxi; Li, Jinmin; Fan, Shoushan
2016-06-01
We report a novel method to fabricate high quality 2-inch freestanding GaN substrate grown on cross-stacked carbon nanotubes (CSCNTs) coated sapphire by hydride vapor phase epitaxy (HVPE). As nanoscale masks, these CSCNTs can help weaken the interface connection and release the compressive stress by forming voids during fast coalescence and also block the propagation of threading dislocations (TDs). During the cool-down process, thermal stress-induced cracks are initiated at the CSCNTs interface with the help of air voids and propagated all over the films which leads to full self-separation of FS-GaN substrate. Raman and photoluminescence spectra further reveal the stress relief and crystalline improvement of GaN with CSCNTs. It is expected that the efficient, low cost and mass-producible technique may enable new applications for CNTs in nitride optoelectronic fields.
10. Preparation of Ag Schottky contacts on n-type GaN bulk crystals grown in nitrogen rich atmosphere by the hydride vapor phase epitaxy technique
Energy Technology Data Exchange (ETDEWEB)
Stübner, R., E-mail: ronald.stuebner@physik.tu-dresden.de; Kolkovsky, Vl.; Weber, J. [Technische Universität Dresden, 01062 Dresden (Germany); Leibiger, Gunnar; Habel, Frank [Freiberger Compound Materials GmbH, 09599 Freiberg (Germany)
2014-10-14
Electrical properties of Schottky contacts on n-type GaN grown in nitrogen rich atmosphere with different N/Ga ratios by hydride vapor phase epitaxy were investigated. We show that tunneling of electrons from the conduction band of GaN to the metal is dominant in our samples. The quality of Schottky contacts does not only depend on surface preparation but also on the growth conditions of the crystals. Schottky contacts on these crystals show an increasing deterioration when higher N/Ga growth ratios are used. We correlate our results with the presence of negatively charged gallium vacancies in the samples. These charges compensate the positively charged donors and lead to a significant increase in series resistance.
11. GaN Growth with Low-Temperature GaN Buffer Layers Directly on Si(111) by Hydride Vapour Phase Epitaxy
Institute of Scientific and Technical Information of China (English)
俞慧强; 陈琳; 张荣; 修向前; 谢自力; 叶宇达; 顾书林; 沈波; 施毅; 郑有蚪
2004-01-01
GaN films are grown on Si(111) with low-temperature GaN (LT-GaN) layers as buffer layers by hydride vapour phase epitaxy (HVPE). The deposition temperature of the LT-GaN layers is changed from 400 to 900 ℃. When the LT-GaN layer is deposited at 600 ℃, GaN films show only c-oriented GaN (0002) and have the band edge emission at 365 nm with no yellow luminescence bands. The results indicate that the LT-GaN layer can effectively block the unexpected Si etching by reactive gas during the GaN growth. However, the surface roughness of these GaN films grown on Si(111) is larger than that of GaN films on c-plane sapphire.
12. The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components Delayed Hydride Cracking
CERN Document Server
Puls, Manfred P
2012-01-01
By drawing together the current theoretical and experimental understanding of the phenomena of delayed hydride cracking (DHC) in zirconium alloys, The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components: Delayed Hydride Cracking provides a detailed explanation focusing on the properties of hydrogen and hydrides in these alloys. Whilst the focus lies on zirconium alloys, the combination of both the empirical and mechanistic approaches creates a solid understanding that can also be applied to other hydride forming metals. This up-to-date reference focuses on documented research surrounding DHC, including current methodologies for design and assessment of the results of periodic in-service inspections of pressure tubes in nuclear reactors. Emphasis is placed on showing that our understanding of DHC is supported by progress across a broad range of fields. These include hysteresis associated with first-order phase transformations; phase relationships in coherent crystalline metallic...
13. Investigation of phase explosion in aluminum induced by nanosecond double pulse technique
Energy Technology Data Exchange (ETDEWEB)
Jafarabadi, Marzieh Akbari; Mahdieh, Mohammad Hossein, E-mail: mahdm@iust.ac.ir
2015-08-15
Highlights: • Single and collinear double pulse configurations were used for laser ablation of aluminum target in air. • The 5, 10, 15 and 20 ns delay times between pre pulse and main pulse in double pulse arrangement was investigated. • In comparison between single and double pulse regimes, the phase explosion threshold fluence is decreased in double pulse configuration. • The plasma shielding effect reduces the crater depth in lower laser fluence in double pulse configuration rather that its in single pulse configuration. - Abstract: In this paper, the influence of double pulse technique on phase explosion threshold in laser ablation of an aluminum target is investigated. Single and double pulse laser ablation of aluminum target was performed by a high power Nd:YAG laser beam in ambient air. In the double pulse excitation, the two pulses were from a single laser source which separated by a delay time in the range of 5–20 ns. Measuring ablation depth and rate, the phase explosion threshold was estimated in double pulse configuration as well as in the single pulse regime. The results show that in comparison between single and double pulse regimes, the phase explosion threshold fluence is decreased in double pulse configuration. The lowest phase explosion threshold fluence of 0.9 J/cm{sup 2} was obtained at 5 ns delay time. The results also show that plasma shielding effect reduced crater depth at a laser fluence which depended on the laser ablation configuration (single pulse or double pulse). The reduction of crater depth occurs at lower laser fluences for double pulse regime.
14. Precipitation and Deposition of Aluminum-Containing Phases in Tank Wastes
Energy Technology Data Exchange (ETDEWEB)
Dabbs, Daniel M.; Aksay, I.A.
2005-12-01
In the first phase of our study, we focused on the use of simple organics to raise the solubility of aluminum oxyhydroxides in high alkaline aqueous solvents. In a limited survey of common organic acids, we determined that citric acid had the highest potential to achieve our goal. However, our subsequent investigation revealed that the citric acid appeared to play two roles in the solutions: first, raising the concentration of aluminum in highly alkaline solutions by breaking up or inhibiting ''seed'' polycations and thereby delaying the nucleation and growth of particles; and second, stabilizing nanometer-sized particles in suspension when nucleation did occur. The results of this work were recently published in Langmuir: D.M. Dabbs, U. Ramachandran, S. Lu, J. Liu, L.-Q. Wang, I.A. Aksay, ''Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid'' Langmuir, 21, 11690-11695 (2005). The second phase of our work involved the solvation of silicon, again in solutions of high alkalinity. Citric acid, due to its unfavorable pKa values, was not expected to be useful with silicon-containing solutions. Here, the use of polyols was determined to be effective in maintaining silicon-containing particles under high pH conditions but at smaller size with respect to standard suspensions of silicon-containing particles. There were a number of difficulties working with highly alkaline silicon-containing solutions, particularly in solutions at or near the saturation limit. Small deviations in pH resulted in particle formation or dissolution in the absence of the organic agents. One of the more significant observations was that the polyols appeared to stabilize small particles of silicon oxyhydroxides across a wider range of pH, albeit this was difficult to quantify due to the instability of the solutions.
15. A comparative study of interatomic potentials for copper and aluminum gas phase sputter atom transport simulations
CERN Document Server
Kuwata, K T; Doyle, J R
2003-01-01
A comparative study of interatomic potential models for use in gas phase sputter atom transport simulations is presented. Quantum chemical interatomic potentials for argon-copper and argon-aluminum are calculated using Kohn-Sham density functional theory utilizing the PW91 functional. These potentials (PW91) are compared to the commonly used Born-Mayer potentials calculated by Abrahamson [Phys. Rev. 178 (1969) 76] using the Thomas-Fermi-Dirac model (TFD) and the screened Coulomb potentials derived from the 'universal' form calculated by Ziegler, Biersack and Littmark (ZBL). Monte Carlo simulations of gas phase sputter atom transport were performed to determine the average energy of atoms arriving at the substrate versus pressure for the three potential models. Overall, the ZBL potential gave results in much better agreement with the PW91 potential than the TFD potential. A characteristic thermalization pressure-distance product of approx 0.11 mTorr cm was found for both copper and aluminum using the PW91 pote...
16. The effect warming time of mechanical properties and structural phase aluminum alloy nickel
International Nuclear Information System (INIS)
Ferrous aluminum alloys as fuel cladding will experience the process of heat treatment above the recrystallization temperature. Temperature and time of heat treatment will affect the nature of the metal. Heating time allows will affect change in mechanical properties, thermal and structure of the metal phase. This study aims to determine the effect of time of heat treatment on mechanical properties and phase metal alloys. Testing the mechanical properties of materials, especially violence done by the method of Vickers. Observation of microstructural changes made by metallographic-optical and phase structure were analyzed Based on the x-ray diffraction patterns Elemental analysis phase alloy compounds made by EDS-SEM. Test results show the nature of violence AlFeNiMg alloy by heating at 500°C with a warm-up time 1 hour, 2 hours and 3 hours respectively decreased range 94.4 HV, 87.6 HV and 85.1 HV. The nature of violence AlFeNi alloy showed a decrease in line with the longer heating time. Metallographic-optical observations show the microstructural changes with increasing heating time. Microstructure shows the longer the heating time trend equi axial shaped grain structure of growing and the results showed a trend analyst diffraction pattern formation and phase θ α phase (FeAl3) in the alloy. (author)
17. Effect of intermetallic phases on the anodic oxidation and corrosion of 5A06 aluminum alloy
Science.gov (United States)
Li, Song-mei; Li, Ying-dong; Zhang, You; Liu, Jian-hua; Yu, Mei
2015-02-01
Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered intermetallic particles were examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) after pretreatment. The anodic film was investigated by transmission electron microscopy (TEM), and its corrosion resistance was analyzed by electrochemical impedance spectroscopy (EIS) and Tafel polarization in NaCl solution. The results show that the size of Al-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the anodic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.
18. Effect of previous phase formation on densification and microstructure of aluminum titanate
International Nuclear Information System (INIS)
Aluminum titanate based ceramics are potential candidates for many industrial applications mainly due to their low coefficient of thermal expansion and high thermal shock resistance. However, these ceramics are susceptible to phase dissociation in temperature range between 1100 and 1300 deg C, with consequent deterioration of properties. In this paper, it was assessed the effect of previous formation of Al2TiO5, obtained by calcination and subsequent grinding of equimolar mixtures of Al2O3 and TiO2, containing MgO and SiO2, additives which promote Al2TiO5 stabilization. Compacted samples from calcinated and non-calcinated powders were evaluated considering densification, formed crystalline phases, as well as grains size and morphology, by means of dilatometer studies, sintering treatments, X-ray diffraction and scanning electron microscopy. The effect of previous formation of Al2TiO5 was associated with the properties and obtained features. (author)
19. Threshold for plasma phase transition of aluminum single crystal induced by hypervelocity impact
International Nuclear Information System (INIS)
Molecular dynamics method is used to study the threshold for plasma phase transition of aluminum single crystal induced by hypervelocity impact. Two effective simulation methods, piston-driven method and multi-scale shock technique, are used to simulate the shock wave. The simulation results from the two methods agree well with the experimental data, indicating that the shock wave velocity is linearly dependent on the particle velocity. The atom is considered to be ionized if the increase of its internal energy is larger than the first ionization energy. The critical impact velocity for plasma phase transition is about 13.0 km/s, corresponding to the threshold of pressure and temperature which is about 220 GPa and 11.0 × 103 K on the shock Hugoniot, respectively
20. Threshold for plasma phase transition of aluminum single crystal induced by hypervelocity impact
Energy Technology Data Exchange (ETDEWEB)
Ju, Yuanyuan; Zhang, Qingming, E-mail: qmzhang@bit.edu.cn [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)
2015-12-15
Molecular dynamics method is used to study the threshold for plasma phase transition of aluminum single crystal induced by hypervelocity impact. Two effective simulation methods, piston-driven method and multi-scale shock technique, are used to simulate the shock wave. The simulation results from the two methods agree well with the experimental data, indicating that the shock wave velocity is linearly dependent on the particle velocity. The atom is considered to be ionized if the increase of its internal energy is larger than the first ionization energy. The critical impact velocity for plasma phase transition is about 13.0 km/s, corresponding to the threshold of pressure and temperature which is about 220 GPa and 11.0 × 10{sup 3 }K on the shock Hugoniot, respectively.
1. Phase III Advanced Anodes and Cathodes Utilized in Energy Efficient Aluminum Production Cells
Energy Technology Data Exchange (ETDEWEB)
R.A. Christini; R.K. Dawless; S.P. Ray; D.A. Weirauch, Jr.
2001-11-05
During Phase I of the present program, Alcoa developed a commercial cell concept that has been estimated to save 30% of the energy required for aluminum smelting. Phase ii involved the construction of a pilot facility and operation of two pilots. Phase iii of the Advanced Anodes and Cathodes Program was aimed at bench experiments to permit the resolution of certain questions to be followed by three pilot cells. All of the milestones related to materials, in particular metal purity, were attained with distinct improvements over work in previous phases of the program. NiO additions to the ceramic phase and Ag additions to the Cu metal phase of the cermet improved corrosion resistance sufficiently that the bench scale pencil anodes met the purity milestones. Some excellent metal purity results have been obtained with anodes of the following composition: Further improvements in anode material composition appear to be dependent on a better understanding of oxide solubilities in molten cryolite. For that reason, work was commissioned with an outside consultant to model the MeO - cryolite systems. That work has led to a better understanding of which oxides can be used to substitute into the NiO-Fe2O3 ceramic phase to stabilize the ferrites and reduce their solubility in molten cryolite. An extensive number of vertical plate bench electrolysis cells were run to try to find conditions where high current efficiencies could be attained. TiB2-G plates were very inconsistent and led to poor wetting and drainage. Pure TiB2 did produce good current efficiencies at small overlaps (shadowing) between the anodes and cathodes. This bench work with vertical plate anodes and cathodes reinforced the importance of good cathode wetting to attain high current efficiencies. Because of those conclusions, new wetting work was commissioned and became a major component of the research during the third year of Phase III. While significant progress was made in several areas, much work needs to be
2. Pole figure measurement of the initial growth of GaN nanoneedles on GaN/Si(111) by using hydride vapor phase epitaxy
Science.gov (United States)
Jeon, Injun; Lee, Ha Young; Noh, Ji-Yeon; Ahn, Hyung Soo; Yi, Sam Nyung; Jeon, Hunsoo; Shin, Min Jeong; Yu, Young Moon; Ha, Dong Han
2016-09-01
We report on crystallographic analyses of one-dimensional GaN nanoneedles grown on a n-GaN epilayer by using hydride vapor phase epitaxy. The nanoneedles were grown with a HCl:NH3 gas flow ratio of 1:38 at 600 °C. The growth time of the GaN nanoneedles affected their morphologies. As time progressed, GaN dots nucleated and then evolved as nanoneedles. The vertical growth rate of GaN nanoneedles was higher than the lateral growth rate under optimized growth conditions. X-ray pole figure measurements were carried out using a four-axis diffractometer. For the sample grown for 20 min, we obtained discrete patterns with six strong dots and weak dough-nut and cotton swab patterns, indicating that most of the nanoneedles were grown ideally, but partially, in the x- y plane with an azimuthal rotation angle ϕ = 15 ~ 45° rotated to the substrate, and a few GaN nanoneedles were tilted by ±4° or by more than 32° from the vertical c-axis.
3. Compression and phase diagram of lithium hydrides at elevated pressures and temperatures by first-principles calculation
Science.gov (United States)
Chen, Yang M.; Chen, Xiang R.; Wu, Qiang; Geng, Hua Y.; Yan, Xiao Z.; Wang, Yi X.; Wang, Zi W.
2016-09-01
High pressure and high temperature properties of AB (A = 6Li, 7Li; B = H, D, T) are comprehensively investigated with first-principles methods. It is found that H‑sublattice features in the low-pressure electronic structure near the Fermi level of LiH are shifted to that dominated by the Li+ sublattice under compression. The lattice dynamics are studied in quasi-harmonic approximation, from which the phonon contribution to the free energy and the isotopic effects are accurately modelled with the aid of a parameterized double-Debye model. The equation of state (EOS) obtained matches perfectly with available static experimental data. The calculated principal Hugoniot is also in accordance with that derived from shock wave experiments. Using the calculated principal Hugoniot and the previous theoretical melting curve, we predict a shock melting point at 56 GPa and 1923 K. In order to establish the phase diagram for LiH, the phase boundaries between the B1 and B2 solid phases are explored. The B1–B2-liquid triple point is determined at about 241 GPa and 2413 K. The remarkable shift in the phase boundaries with isotopic effect and temperature reveal the significant role played by lattice vibrations. Furthermore, the Hugoniot of the static-dynamic coupling compression is assessed. Our EOS suggests that a precompression of the sample to 50 GPa will allow the shock Hugoniot to pass through the triple point and enter the B2 solid phase. This transition leads to a discontinuity with 4.6% volume collapse—about four times greater than the same B1–B2 transition at zero temperature.
4. Compression and phase diagram of lithium hydrides at elevated pressures and temperatures by first-principles calculations
CERN Document Server
Chen, Yang M; Wu, Qiang; Geng, Hua Y; Yan, Xiao Z; Wang, Yi X; Wang, Zi W
2016-01-01
High pressure and high temperature properties of AB (A = $^6$Li, $^7$Li; B = H, D, T) are investigated with first-principles method comprehensively. It is found that the H$^{-}$ sublattice features in the low-pressure electronic structure near the Fermi level of LiH are shifted to that dominated by the Li$^{+}$ sublattice in compression. The lattice dynamics is studied in quasi-harmonic approximation, from which the phonon contribution to the free energy and the isotopic effects are accurately modelled with the aid of a parameterized double-Debye model. The obtained equation of state (EOS) matches perfectly with available static experimental data. The calculated principal Hugoniot is also in accordance with that derived from shock wave experiments. Using the calculated principal Hugoniot and the previous theoretical melting curve, we predict a shock melting point at 56 GPa and 1923 K. In order to establish the phase diagram for LiH, the phase boundaries between the B1 and B2 solid phases are explored. The B1-...
5. Regenerative Hydride Heat Pump
Science.gov (United States)
Jones, Jack A.
1992-01-01
Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.
6. On-line electrochemically controlled in-tube solid phase microextraction of inorganic selenium followed by hydride generation atomic absorption spectrometry.
Science.gov (United States)
Asiabi, Hamid; Yamini, Yadollah; Seidi, Shahram; Shamsayei, Maryam; Safari, Meysam; Rezaei, Fatemeh
2016-05-30
In this work, for the first time, a rapid, simple and sensitive microextraction procedure is demonstrated for the matrix separation, preconcentration and determination of inorganic selenium species in water samples using an electrochemically controlled in-tube solid phase microextraction (EC-in-tube SPME) followed by hydride generation atomic absorption spectrometry (HG-AAS). In this approach, in which EC-in-tube SPME and HG-AAS system were combined, the total analysis time, was decreased and the accuracy, repeatability and sensitivity were increased. In addition, to increases extraction efficiency, a novel nanostructured composite coating consisting of polypyrrole (PPy) doped with ethyleneglycol dimethacrylate (EGDMA) was prepared on the inner surface of a stainless-steel tube by a facile electrodeposition method. To evaluate the offered setup and the new PPy-EGDMA coating, it was used to extract inorganic selenium species in water samples. Extraction of inorganic selenium species was carried out by applying a positive potential through the inner surface of coated in-tube under flow conditions. Under the optimized conditions, selenium was detected in amounts as small as 4.0 parts per trillion. The method showed good linearity in the range of 0.012-200 ng mL(-1), with coefficients of determination better than 0.9996. The intra- and inter-assay precisions (RSD%, n = 5) were in the range of 2.0-2.5% and 2.7-3.2%, respectively. The validated method was successfully applied for the analysis of inorganic selenium species in some water samples and satisfactory results were obtained. PMID:27154830
7. Synthesis, structure and gas-phase reactivity of the mixed silver hydride borohydride nanocluster [Ag3(μ3-H)(μ3-BH4)L(Ph)3]BF4 (L(Ph) = bis(diphenylphosphino)methane).
Science.gov (United States)
Zavras, Athanasios; Ariafard, Alireza; Khairallah, George N; White, Jonathan M; Mulder, Roger J; Canty, Allan J; O'Hair, Richard A J
2015-11-21
Borohydrides react with silver salts to give products that span multiple scales ranging from discrete mononuclear compounds through to silver nanoparticles and colloids. The cluster cations [Ag3(H)(BH4)L3](+) are observed upon electrospray ionization mass spectrometry of solutions containing sodium borohydride, silver(I) tetrafluoroborate and bis(dimethylphosphino)methane (L(Me)) or bis(diphenylphosphino)methane (L(Ph)). By adding NaBH4 to an acetonitrile solution of AgBF4 and L(Ph), cooled to ca. -10 °C, we have been able to isolate the first mixed silver hydride borohydride nanocluster, [Ag3(μ3-H)(μ3-BH4)L(Ph)3]BF4, and structurally characterise it via X-ray crystallography. Combined gas-phase experiments (L(Me) and L(Ph)) and DFT calculations (L(Me)) reveal how loss of a ligand from the cationic complexes [Ag3(H)(BH4)L3](+) provides a change in geometry that facilitates subsequent loss of BH3 to produce the dihydride clusters, [Ag3(H)2Ln](+) (n = 1 and 2). Together with the results of previous studies (Girod et al., Chem. - Eur. J., 2014, 20, 16626), this provides a direct link between mixed silver hydride/borohydride nanoclusters, silver hydride nanoclusters, and silver nanoclusters.
8. Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications
Energy Technology Data Exchange (ETDEWEB)
Rodak, L.E.; Kuchibhatla, S.; Famouri, P.; Ting, L.; Korakakis, D.
2008-01-01
Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.
9. Role of aluminum doping on phase transformations in nanoporous titania anodic oxides
Energy Technology Data Exchange (ETDEWEB)
Bayata, Fatma [Istanbul Bilgi University, Department of Mechanical Engineering, 34060, Eyup, Istanbul (Turkey); Ürgen, Mustafa, E-mail: urgen@itu.edu.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469, Maslak, Istanbul (Turkey)
2015-10-15
The role of aluminium doping on anatase to rutile phase transformation of nanoporous titanium oxide films were investigated. For this purpose pure and aluminum doped metal films were deposited on alumina substrates by cathodic arc physical deposition. The nanoporous anodic oxides were prepared by porous anodizing of pure and aluminum doped titanium metallic films in an ethylene glycol + NH{sub 4}F based electrolyte. Nanoporous amorphous structures with 60–80 nm diameter and 2–4 μm length were formed on the surfaces of alumina substrates. The amorphous undoped and Al-doped TiO{sub 2} anodic oxides were heat-treated at different temperatures in the range of 280–720 °C for the investigation of their crystallization behavior. The combined effects of nanoporous structure and Al doping on crystallization behavior of titania were investigated using X-ray diffraction (XRD) and micro Raman analysis. The results indicated that both Al ions incorporated into the TiO{sub 2} structure and the nanoporous structure retarded the rutile formation. It was also revealed that presence or absence of metallic film underneath the nanopores has a major contribution to anatase-rutile transformation. - Highlights: • Al-doped TiO{sub 2} nanopores were grown on alumina substrates using anodization method. • The crystallization behavior of nanoporous Al-doped TiO{sub 2} were investigated. • Al doping into nanoporous TiO{sub 2} retarded the anatase-rutile transformation. • Nanostructuring has significant role in controlling rutile formation temperature. • The absence of the metallic film under the nanopores delayed the rutile formation.
10. The effect of ductile phase reinforcements on dynamic fracture toughness of discontinuously reinforced aluminum (D.R.A.) alloys
International Nuclear Information System (INIS)
Discontinuously Reinforced Aluminum Alloys were tested under impact loading using the modified fracture bar apparatus. The apparatus is a modified version of split Hopkinson pressure bar and uses stress wave theory to give an experimental reading of Force-time history during crack initiation and propagation. Specimens of composite 840-854 materials under investigation were made of 7093 Al/SiC/15p toughened with different ductile phase -3 reinforcements. The ductile phase reinforcements were made with different Aluminum Alloys and commercially) sites, Journal of pure aluminum. The purpose of ductile phase reinforcements was to introduce impediments in the crack path thus increasing the crack propagation energy. The crack propagation velocity was measured using crack propagation gages. Stress intensity factor as a function of time was calculated to find out the peak values of K/sub dyn/(t) at crack initiation. Investigations were also made to find out the Crack Arrest Fracture Toughness. It was found out that the commercial purity aluminum reinforcements could act as crack arrestors by blunting the crack tip. (author)
11. Characterization of Phases in an As-cast Copper-Manganese-Aluminum Alloy
Institute of Scientific and Technical Information of China (English)
2006-01-01
Copper-manganese-aluminum (CMA) alloys, containing small additions of Fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their microstructure can show wide variations. The morphology, crystallography and composition of the phases presented in an as-cast (CMA) alloy of nominal composition Cu-14%Mn-8%Al-3%Fe-2%Ni were investigated using optical, electron optical, and microprobe analytical techniques. The as-cast microstructure consisted of the grains of fcc α and bcc β-phases alongwith intermetallic precipitates of various morphologies. The dendritic-shaped particles and the cuboid-shaped precipitates, which were rich in Fe and Mn and had an fcc DO3 structure. These four different morphologies of intermetallic precipitates exhibited discrete orientationrelationships with the α-matrix. The β-grains only contained very small cuboid shaped precipitates, which could only be resolved through transmission electron microscopy. These precipitates were found to be based on Fe3Al and had the DO3 structure.
12. Spin Forming Aluminum Crew Module (CM) Metallic Aft Pressure Vessel Bulkhead (APVBH) - Phase II
Science.gov (United States)
Hoffman, Eric K.; Domack, Marcia S.; Torres, Pablo D.; McGill, Preston B.; Tayon, Wesley A.; Bennett, Jay E.; Murphy, Joseph T.
2015-01-01
13. Electrochemical and Optical Properties of Magnesium-Alloy Hydrides Reviewed
Directory of Open Access Journals (Sweden)
Thirugnasambandam G. Manivasagam
2012-10-01
Full Text Available As potential hydrogen storage media, magnesium based hydrides have been systematically studied in order to improve reversibility, storage capacity, kinetics and thermodynamics. The present article deals with the electrochemical and optical properties of Mg alloy hydrides. Electrochemical hydrogenation, compared to conventional gas phase hydrogen loading, provides precise control with only moderate reaction conditions. Interestingly, the alloy composition determines the crystallographic nature of the metal-hydride: a structural change is induced from rutile to fluorite at 80 at.% of Mg in Mg-TM alloy, with ensuing improved hydrogen mobility and storage capacity. So far, 6 wt.% (equivalent to 1600 mAh/g of reversibly stored hydrogen in MgyTM(1-yHx (TM: Sc, Ti has been reported. Thin film forms of these metal-hydrides reveal interesting electrochromic properties as a function of hydrogen content. Optical switching occurs during (dehydrogenation between the reflective metal and the transparent metal hydride states. The chronological sequence of the optical improvements in optically active metal hydrides starts with the rare earth systems (YHx, followed by Mg rare earth alloy hydrides (MgyGd(1-yHx and concludes with Mg transition metal hydrides (MgyTM(1-yHx. In-situ optical characterization of gradient thin films during (dehydrogenation, denoted as hydrogenography, enables the monitoring of alloy composition gradients simultaneously.
14. Conference 'Chemistry of hydrides' Proceedings
International Nuclear Information System (INIS)
This collection of thesis of conference of Chemistry hydrides presents the results of investigations concerning of base questions of chemistry of nonorganic hydrides, including synthesis questions, studying of physical and chemical properties, thermodynamics, analytical chemistry, investigation of structure, equilibriums in the systems of metal-hydrogen, behaviour of nonorganic hydrides in non-water mediums and applying investigations in the chemistry area and technology of nonorganic hydrides
15. Determination of As(III) and total inorganic As in water samples using an on-line solid phase extraction and flow injection hydride generation atomic absorption spectrometry
Energy Technology Data Exchange (ETDEWEB)
Sigrist, Mirna, E-mail: msigrist@fiq.unl.edu.ar [Laboratorio Central, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2654-Piso 6, (3000) Santa Fe (Argentina); Albertengo, Antonela; Beldomenico, Horacio [Laboratorio Central, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2654-Piso 6, (3000) Santa Fe (Argentina); Tudino, Mabel [Laboratorio de Analisis de Trazas, Departamento de Quimica Inorganica, Analitica y Quimica Fisica/INQUIMAE, Facultad de Ciencias Exactas y Naturales, Pabellon II, Ciudad Universitaria (1428), Buenos Aires (Argentina)
2011-04-15
A simple and robust on-line sequential injection system based on solid phase extraction (SPE) coupled to a flow injection hydride generation atomic absorption spectrometer (FI-HGAAS) with a heated quartz tube atomizer (QTA) was developed and optimized for the determination of As(III) in groundwater without any kind of sample pretreatment. The method was based on the selective retention of inorganic As(V) that was carried out by passing the filtered original sample through a cartridge containing a chloride-form strong anion exchanger. Thus the most toxic form, inorganic As(III), was determined fast and directly by AsH{sub 3} generation using 3.5 mol L{sup -1} HCl as carrier solution and 0.35% (m/v) NaBH{sub 4} in 0.025% NaOH as the reductant. Since the uptake of As(V) should be interfered by several anions of natural occurrence in waters, the effect of Cl{sup -}, SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, HPO{sub 4}{sup 2-}, HCO{sub 3}{sup -} on retention was evaluated and discussed. The total soluble inorganic arsenic concentration was determined on aliquots of filtered samples acidified with concentrated HCl and pre-reduced with 5% KI-5% C{sub 6}H{sub 8}O{sub 6} solution. The concentration of As(V) was calculated by difference between the total soluble inorganic arsenic and As(III) concentrations. Detection limits (LODs) of 0.5 {mu}g L{sup -1} and 0.6 {mu}g L{sup -1} for As(III) and inorganic total As, respectively, were obtained for a 500 {mu}L sample volume. The obtained limits of detection allowed testing the water quality according to the national and international regulations. The analytical recovery for water samples spiked with As(III) ranged between 98% and 106%. The sampling throughput for As(III) determination was 60 samples h{sup -1}. The device for groundwater sampling was especially designed for the authors. Metallic components were avoided and the contact between the sample and the atmospheric oxygen was carried to a minimum. On-field arsenic species
16. Effects of AlN nucleation layers on the growth of AlN films using high temperature hydride vapor phase epitaxy
Energy Technology Data Exchange (ETDEWEB)
Balaji, M. [Science et Ingenierie des Materiaux et des Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Heres (France); ACERDE, 452 rue des sources, 38920 Crolles (France); Crystal Growth Centre, Anna University-Chennai, Chennai 600025 (India); Claudel, A. [ACERDE, 452 rue des sources, 38920 Crolles (France); Fellmann, V. [Science et Ingenierie des Materiaux et des Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Heres (France); Gelard, I. [ACERDE, 452 rue des sources, 38920 Crolles (France); Blanquet, E., E-mail: elisabeth.blanquet@simap.grenoble-inp.fr [Science et Ingenierie des Materiaux et des Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Heres (France); Boichot, R. [Science et Ingenierie des Materiaux et des Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Heres (France); Pierret, A. [Departement de Mesures Physiques, ONERA, Chemin de la Huniere, 91761 Palaiseau Cedex (France); CEA-CNRS Group ' NanoPhysique et SemiConducteurs' , INAC/SP2M/NPSC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble, Cedex 9 (France); and others
2012-06-15
Highlights: Black-Right-Pointing-Pointer Growth of AlN Nucleation layers and its effect on high temperature AlN films quality were investigated. Black-Right-Pointing-Pointer AlN nucleation layers stabilizes the epitaxial growth of AlN and improves the surface morphology of AlN films. Black-Right-Pointing-Pointer Increasing growth temperature of AlN NLs as well as AlN films improves the structural quality and limits the formation of cracks. - Abstract: AlN layers were grown on c-plane sapphire substrates with AlN nucleation layers (NLs) using high temperature hydride vapor phase epitaxy (HT-HVPE). Insertion of low temperature NLs, as those typically used in MOVPE process, prior to the high temperature AlN (HT-AlN) layers has been investigated. The NLs surface morphology was studied by atomic force microscopy (AFM) and NLs thickness was measured by X-ray reflectivity. Increasing nucleation layer deposition temperature from 650 to 850 Degree-Sign C has been found to promote the growth of c-oriented epitaxial HT-AlN layers instead of polycrystalline layers. The growth of polycrystalline layers has been related to the formation of dis-oriented crystallites. The density of such disoriented crystallites has been found to decrease while increasing NLs deposition temperature. The HT-AlN layers have been characterized by X-ray diffraction {theta} - 2{theta} scan and (0 0 0 2) rocking curve measurement, Raman and photoluminescence spectroscopies, AFM and field emission scanning electron microscopy. Increasing the growth temperature of HT-AlN layers from 1200 to 1400 Degree-Sign C using a NL grown at 850 Degree-Sign C improves the structural quality as well as the surface morphology. As a matter of fact, full-width at half-maximum (FWHM) of 0 0 0 2 reflections was improved from 1900 to 864 arcsec for 1200 Degree-Sign C and 1400 Degree-Sign C, respectively. Related RMS roughness also found to decrease from 10 to 5.6 nm.
17. Nanoindentation measurements of the mechanical properties of zirconium matrix and hydrides in unirradiated pre-hydrided nuclear fuel cladding
Science.gov (United States)
Rico, A.; Martin-Rengel, M. A.; Ruiz-Hervias, J.; Rodriguez, J.; Gomez-Sanchez, F. J.
2014-09-01
It is well known that the mechanical properties of the nuclear fuel cladding may be affected by the presence of hydrides. The average mechanical properties of hydrided cladding have been extensively investigated from a macroscopic point of view. In addition, the mechanical and fracture properties of bulk hydride samples fabricated from zirconium plates have also been reported. In this paper, Young's modulus, hardness and yield stress are measured for each phase, namely zirconium hydrides and matrix, of pre-hydrided nuclear fuel cladding. To this end, nanoindentation tests were performed on ZIRLO samples in as-received state, on a hydride blister and in samples with 150 and 1200 ppm of hydrogen homogeneously distributed along the hoop direction of the cladding. The results show that the measured mechanical properties of the zirconium hydrides and ZIRLO matrix (Young's modulus, hardness and yield stress) are rather similar. From the experimental data, the hydride volume fraction in the cladding samples with 150 and 1200 ppm was estimated and the average mechanical properties were calculated by means of the rule of mixtures. These values were compared with those obtained from ring compression tests. Good agreement between the results obtained by both methods was found.
18. Submillimeter Spectroscopy of Hydride Molecules
Science.gov (United States)
Phillips, T. G.
1998-05-01
Simple hydride molecules are of great importance in astrophysics and astrochemistry. Physically they dominate the cooling of dense, warm phases of the ISM, such as the cores and disks of YSOs. Chemically they are often stable end points of chemical reactions, or may represent important intermediate stages of the reaction chains, which can be used to test the validity of the process. Through the efforts of astronomers, physicists, chemists, and laboratory spectroscopists we have an approximate knowledge of the abundance of some of the important species, but a great deal of new effort will be required to achieve the comprehensive and accurate data set needed to determine the energy balance and firmly establish the chemical pathways. Due to the low moment of inertia, the hydrides rotate rapidly and so have their fundamental spectral lines in the submillimeter. Depending on the cloud geometry and temperature profile they may be observed in emission or absorption. Species such as HCl, HF, OH, CH, CH(+) , NH_2, NH_3, H_2O, H_2S, H_3O(+) and even H_3(+) have been detected, but this is just a fraction of the available set. Also, most deduced abundances are not nearly sufficiently well known to draw definitive conclusions about the chemical processes. For example, the most important coolant for many regions, H_2O, has a possible range of deduced abundance of a factor of 1000. The very low submillimeter opacity at the South Pole site will be a significant factor in providing a new capabilty for interstellar hydride spectroscopy. The new species and lines made available in this way will be discussed.
19. ENVIRONMENTALLY COMPLIANT CORROSION-ACTIVATED INHIBITOR SYSTEM FOR ALUMINUM ALLOYS - PHASE I
Science.gov (United States)
The federal government is estimated to spend $1 billion on painting/repainting aircraft annually. Aircraft have surfaces composed of aluminum alloys that are highly susceptible to corrosion and must be protected with corrosion-preventative treatments that typically conta... 20. Results of NDE Technique Evaluation of Clad Hydrides Energy Technology Data Exchange (ETDEWEB) Dennis C. Kunerth 2014-09-01 This report fulfills the M4 milestone, M4FT-14IN0805023, Results of NDE Technique Evaluation of Clad Hydrides, under Work Package Number FT-14IN080502. During service, zirconium alloy fuel cladding will degrade via corrosion/oxidation. Hydrogen, a byproduct of the oxidation process, will be absorbed into the cladding and eventually form hydrides due to low hydrogen solubility limits. The hydride phase is detrimental to the mechanical properties of the cladding and therefore it is important to be able to detect and characterize the presence of this constituent within the cladding. Presently, hydrides are evaluated using destructive examination. If nondestructive evaluation techniques can be used to detect and characterize the hydrides, the potential exists to significantly increase test sample coverage while reducing evaluation time and cost. To demonstrate the viability this approach, an initial evaluation of eddy current and ultrasonic techniques were performed to demonstrate the basic ability to these techniques to detect hydrides or their effects on the microstructure. Conventional continuous wave eddy current techniques were applied to zirconium based cladding test samples thermally processed with hydrogen gas to promote the absorption of hydrogen and subsequent formation of hydrides. The results of the evaluation demonstrate that eddy current inspection approaches have the potential to detect both the physical damage induced by hydrides, e.g. blisters and cracking, as well as the combined effects of absorbed hydrogen and hydride precipitates on the electrical properties of the zirconium alloy. Similarly, measurements of ultrasonic wave velocities indicate changes in the elastic properties resulting from the combined effects of absorbed hydrogen and hydride precipitates as well as changes in geometry in regions of severe degradation. However, for both approaches, the signal responses intended to make the desired measurement incorporate a number of contributing 1. Gaseous Phase and Electrochemical Hydrogen Storage Properties of Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu for Nickel Metal Hydride Battery Applications Directory of Open Access Journals (Sweden) Jean Nei 2016-07-01 Full Text Available Structural, gaseous phase hydrogen storage, and electrochemical properties of a series of the Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu metal hydride alloys were studied. X-ray diffraction (XRD and scanning electron microscopy (SEM revealed the multi-phase nature of all alloys, which were composed of a stoichiometric TiNi matrix, a hyperstoichiometric TiNi minor phase, and a Ti2Ni secondary phase. Improvement in synergetic effects between the main TiNi and secondary Ti2Ni phases, determined by the amount of distorted lattice region in TiNi near Ti2Ni, was accomplished by the substitution of an element with a higher work function, which consequently causes a dramatic increase in gaseous phase hydrogen storage capacity compared to the Ti50Zr1Ni49 base alloy. Capacity performance is further enhanced in the electrochemical environment, especially in the cases of the Ti50Zr1Ni49 base alloy and Ti50Zr1Ni44Co5 alloy. Although the TiNi-based alloys in the current study show poorer high-rate performances compared to the commonly used AB5, AB2, and A2B7 alloys, they have adequate capacity performances and also excel in terms of cost and cycle stability. Among the alloys investigated, the Ti50Zr1Ni44Fe5 alloy demonstrated the best balance among capacity (394 mAh·g−1, high-rate performance, activation, and cycle stability and is recommended for follow-up full-cell testing and as the base composition for future formula optimization. A review of previous research works regarding the TiNi metal hydride alloys is also included. 2. Preliminary results on the determination of ultratrace amounts of cadmium in tea samples using a flow injection on-line solid phase extraction separation and preconcentration technique to couple with a sequential injection hydride generation atomic fluorescence spectrometry. Science.gov (United States) Duan, Taicheng; Song, Xuejie; Jin, Dan; Li, Hongfei; Xu, Jingwei; Chen, Hangting 2005-10-31 In this work, a method was developed for determination of ultra-trace levels of Cd in tea samples by atomic fluorescence spectrometry (AFS). A flow injection solid phase extraction (FI-SPE) separation and preconcentration technique, to on-line couple with a sequential injection hydride generation (SI-HG) technique is employed in this study. Cd was preconcentrated on the SPE column, which was made from a neutral extractant named Cyanex 923, while other matrix ions or interfering ions were completely or mostly separated off. Conditions for the SPE separation and preconcentration, as well as conditions for the HG technique, were studied. Due to the separation of interfering elements, Cd hydride generation efficiency could be greatly enhanced with the sole presence of Co(2+) with a concentration of 200mugL(-1), which is much lower than those in other works previously reported. Interferences on both the Cd separation and preconcentration, and Cd hydride generation (HG) were investigated; it showed that both the separation and preconcentration system, and the HG system had a strong anti-interference ability. The SPE column could be repeatedly used at least 400 times, a R.S.D. of 0.97% was obtained for 6 measurements of Cd with 0.2mugL(-1) and a correlation coefficiency of 1.0000 was obtained for the measurement of a series of solutions with Cd concentrations from 0.1 to 2mugL(-1). The method has a low detection limit of 10.8ngL(-1) for a 25mL solution and was successfully validated by using two tea standard reference materials (GBW08513 and GBW07605). 3. Properties of GaN film grown by hydride vapor phase epitaxy%氢化物气相外延生长GaN膜性质研究 Institute of Scientific and Technical Information of China (English) 刘战辉; 张李骊; 李庆芳; 修向前; 张荣; 谢自力 2013-01-01 利用氢化物气相外延技术在c 面蓝宝石上生长得到纤锌矿结构 GaN 膜.采用高分辨 X 射线衍射、拉曼光谱和光致发光谱对GaN 外延膜进行了结构表征和光学性质研究,重点探讨了光致发光谱的温度变化特性.样品(002)面和(102)面摇摆曲线半高宽分别为322和375 arcsec,表明生长的 GaN 膜具有较好的晶体质量.高分辨 X射线衍射、拉曼光谱和光致发光谱测试表明,外延膜中存在0．26 GPa 的面内压应力.变温光致发光谱研究发现 GaN 外延膜中 A 自由激子发射峰和施主束缚激子发射峰随温度变化服从能带收缩理论.但由于 A 自由激子单声子伴峰可能是一种与自由激子动能变化相关的自由激子-声子相互作用的复合机制,导致其峰位呈现先蓝移后红移变化,以及其积分强度出现先增加后降低的现象.%The high crystal quality GaN film has been successfully grown by hydride vapor phase epitaxy (HVPE)and the properties of GaN epilayers have been investigated by high-resolution X-ray diffraction (HRXRD),Raman and photoluminescence (PL)measurements.The temperature dependence of photolumines-cence has been studied particularly.X-ray rocking curves (XRC)showed that the full widths at half maximum (FWHM)of (002 )and (102 )were 322 and 375 arcsec,respectively.Temperature-dependent PL spectra showed that the neutral donor bound excitons (D0 X)emission and free A-excitons recombination peaks reflected the shrinkage of the band gap,but the peak energy and the integrated intensity of 1-longitudinal optical (LO) phonon replica of the free A-excitons exhibited non-monotonic variations with increasing temperature,which might be related to the exciton-polariton dispersion effects of the free excitons caused by gain extra kinetic ener-gy with increasing temperature.HRXRD measurements,Raman and PL spectra all revealed that biaxial in-plane compressive strain (about 0.26 GPa)existed in the GaN layer and the 4. Fabrication and Structure Characterization of Alumina-Aluminum Interpenetrating Phase Composites Science.gov (United States) Dolata, Anna J. 2016-08-01 Alumina-Aluminum composites with interpenetrating networks structure belong to advanced materials with potentially better properties when compared with composites reinforced by particles or fibers. The paper presents the experimental results of fabrication and structure characterization of Al matrix composites locally reinforced via Al2O3 ceramic foam. The composites were obtained using centrifugal infiltration of porous ceramics by liquid aluminum alloy. Both scanning electron microscopy (SEM + EDS) and x-ray tomography were used to determine the structure of foams and composites especially in reinforced areas. The quality of castings, degree of pore filling in ceramic foams by Al alloy, and microstructure in area of interface were assessed. 5. Air and metal hydride battery Energy Technology Data Exchange (ETDEWEB) Lampinen, M.; Noponen, T. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Applied Thermodynamics 1998-12-31 The main goal of the air and metal hydride battery project was to enhance the performance and manufacturing technology of both electrodes to such a degree that an air-metal hydride battery could become a commercially and technically competitive power source for electric vehicles. By the end of the project it was possible to demonstrate the very first prototype of the air-metal hydride battery at EV scale, achieving all the required design parameters. (orig.) 6. Electrochemical process and production of novel complex hydrides Science.gov (United States) Zidan, Ragaiy 2013-06-25 A process of using an electrochemical cell to generate aluminum hydride (AlH.sub.3) is provided. The electrolytic cell uses a polar solvent to solubilize NaAlH.sub.4. The resulting electrochemical process results in the formation of AlH.sub.3. The AlH.sub.3 can be recovered and used as a source of hydrogen for the automotive industry. The resulting spent aluminum can be regenerated into NaAlH.sub.4 as part of a closed loop process of AlH.sub.3 generation. 7. Analysis of Intermetallic Phases Formed on Surface Vapor Oxidized H13 Hot Work Steels in Molten Aluminum Institute of Scientific and Technical Information of China (English) WANGRong; WUXiao-chun; MINYong-an 2004-01-01 In this paper, the author dipped surface vapor oxidized H13 steel specimens into 700℃ molten aluminum liquid for a certain period of time. Analyze the intermetallic phases formed on the H 13 samples surface with optical microscope and X-ray diffraction method. The observation of immersion test sample's cross-section shows that Fe304 film will protect die substrate from molten aluminum erosion. The identification of the intermetallic phases reveals that they consist of 2 parts, which is named as the composite layer and the compact layer. Further investigations are made in order to know the phase constituents of the 2 layers, they are Al8Fe2Si (outer composite layer), (AlCuMg) and Al5Fe2 (compact layer), respectively. The experimental results show that on the same specimen, a convex surface with bigger radius of curvature is more likely to be molten and the melting loss speed is also faster than a flat and smooth surface. The thickness of compact layer on a smooth surface is much bigger than that of the convex surface. Therefore, the author supposes the compact layer is favorable in stabilizing the die surface material from further melting loss, as their formation on the die surface, the melting loss speed will decrease. 8. Analysis of Intermetallic Phases Formed on Surface Vapor Oxidized H13 Hot Work Steels in Molten Aluminum Institute of Scientific and Technical Information of China (English) WANG Rong; WU Xiao-chun; MIN Yong-an 2004-01-01 In this paper, the author dipped surface vapor oxidized H13 steel specimens into 700℃ molten aluminum liquid for a certain period of time. Analyze the intermetallic phases formed on the H13 samples surface with optical microscope and X-ray diffraction method. The observation of immersion test sample's cross-section shows that Fe3O4 film will protect die substrate from molten aluminum erosion. The identification of the intermetallic phases reveals that they consist of 2parts, which is named as the composite layer and the compact layer. Further investigations are made in order to know the phase constituents of the 2 layers, they are Al8Fe2Si (outer composite layer), (AlCuMg) and Al5Fe2 (compact layer),respectively. The experimental results show that on the same specimen, a convex surface with bigger radius of curvature is more likely to be molten and the melting loss speed is also faster than a flat and smooth surface. The thickness of compact layer on a smooth surface is much bigger than that of the convex surface. Therefore, the author supposes the compact layer is favorable in stabilizing the die surface material from further melting loss, as their formation on the die surface, the melting loss speed will decrease. 9. Analysis of time phase of characteristic rad iation in plasma induced by laser ablating aluminum Institute of Scientific and Technical Information of China (English) 2001-01-01 With time- and space-resolved technique, we have recorde d time-resolved spectra of irradiation of the plasma induced by Nd: YAG laser a blating metal Aluminum in Ar, in which, laser pulse-energy was set up to 145 mJ /pulse and the buffer pressure 100 kpa. The continuum radiation and special emis sion of Aluminum plasma were studied based on the records. According to time dis tribution of Al Ⅰ396.15 nm emission, we analyzed the time differences between c haracteristic and continuum radiation evolving. We tried to explain the time pha ses of characteristic radiation evolving with traditional theoretical model of a tomic transition. As the result, we found that it was difficult to explain our e xperimental results with the model. In order to explain our experimental results , we need new model or to improve the traditional theoretical model of atomic tr ansition. 10. Phase Evolution and Mechanical Behavior of the Semi-Solid SIMA Processed 7075 Aluminum Alloy OpenAIRE Behzad Binesh; Mehrdad Aghaie-Khafri 2016-01-01 Microstructural and mechanical behaviors of semi-solid 7075 aluminum alloy were investigated during semi-solid processing. The strain induced melt activation (SIMA) process consisted of applying uniaxial compression strain at ambient temperature and subsequent semi-solid treatment at 600–620 °C for 5–35 min. Microstructures were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). During the isothermal heating, intermetallic p... 11. Advanced powder metallurgy aluminum alloys via rapid solidification technology, phase 2 Science.gov (United States) Ray, Ranjan; Jha, Sunil C. 1987-01-01 Marko's rapid solidification technology was applied to processing high strength aluminum alloys. Four classes of alloys, namely, Al-Li based (class 1), 2124 type (class 2), high temperature Al-Fe-Mo (class 3), and PM X7091 type (class 4) alloy, were produced as melt-spun ribbons. The ribbons were pulverized, cold compacted, hot-degassed, and consolidated through single or double stage extrusion. The mechanical properties of all four classes of alloys were measured at room and elevated temperatures and their microstructures were investigated optically and through electron microscopy. The microstructure of class 1 Al-Li-Mg alloy was predominantly unrecrystallized due to Zr addition. Yield strengths to the order of 50 Ksi were obtained, but tensile elongation in most cases remained below 2 percent. The class 2 alloys were modified composition of 2124 aluminum alloy, through addition of 0.6 weight percent Zr and 1 weight percent Ni. Nickel addition gave rise to a fine dispersion of intermetallic particles resisting coarsening during elevated temperature exposure. The class 2 alloy showed good combination of tensile strength and ductility and retained high strength after 1000 hour exposure at 177 C. The class 3 Al-Fe-Mo alloy showed high strength and good ductility both at room and high temperatures. The yield and tensile strength of class 4 alloy exceeded those of the commercial 7075 aluminum alloy. 12. RESEARCH OF INFLUENCE OF THE IRON CONTENT ON FORMATION OF IRON-BEARING PHASES IN FOUNDRY ALUMINUM ALLOYS Directory of Open Access Journals (Sweden) V. I. Gorbachiova 2013-01-01 Full Text Available The microstructure and microhardness of aluminum and silumin аК12 with iron content of 0 to 12 mas.% produced by sand casting and mol casting have been investigated. For the Al–Si–Fe and Al–Si–Fe–Mn systems the portions of the liquidus surfaces, which correspond to commercial silumin compositions, have been calculated using the updated thermodynamic model of the Al– Si–Fe system and COST–507 database. The area of primary crystallization of the iron-containing a and b phases is assessed for the commercial silumin. It has been proved that manganese promotes the formation of the iron-containing a-phase in the commercial silumin. 13. Energy Efficient Aluminum Production - Pilot-Scale Cell Tests - Final Report for Phase I and Phase II Energy Technology Data Exchange (ETDEWEB) R. A. Christini 1999-12-30 A cermet anode that produces oxygen and a cathode material that is wetted by aluminum can provide a dimensionally stable inter-electrode distance in the Hall-Heroult cell. This can be used to greatly improve the energy and/or productivity efficiencies. The concept, which was developed and tested, uses a system of vertically interleaved anodes and cathodes. The major advantage of this concept is the significant increase in electrochemical surface area compared to a horizontal orientation of anode and cathode that is presently used in the Hall-Heroult process. This creates an additional advantage for energy reduction of 1.3 kWh/lb or a 20% productivity improvement. The voltages obtained in an optimized cell test met the energy objectives of the project for at least two weeks. An acceptable current efficiency was never proven, however, during either pilot scale or bench scale tests with the vertical plate configuration. This must be done before a vertical cell can be considered viab le. Anode corrosion rate must be reduced by at least a factor of three in order to produce commercial purity aluminum. It is recommended that extensive theoretical and bench scale investigations be done to improve anode materials and to demonstrate acceptable current efficiencies in a vertical plate cell before pilot scale work is continued. 14. Calcium-aluminum-silicate-hydrate "cement" phases and rare Ca-zeolite association at Colle Fabbri, Central Italy Science.gov (United States) Stoppa, F.; Scordari, F.; Mesto, E.; Sharygin, V.; Bortolozzi, G. 2010-06-01 Very high temperature, Ca-rich alkaline magma intruded an argillite formation at Colle Fabbri, Central Italy, producing cordierite-tridymite metamorphism in the country rocks. An intense Ba-rich sulphate-carbonate-alkaline hydrothermal plume produced a zone of mineralization several meters thick around the igneous body. Reaction of hydrothermal fluids with country rocks formed calcium-silicate-hydrate (CSH), i.e., tobermorite-afwillite-jennite; calcium-aluminum-silicate-hydrate (CASH) — "cement" phases - i.e., thaumasite, strätlingite and an ettringite-like phase and several different species of zeolites: chabazite-Ca, willhendersonite, gismon-dine, three phases bearing Ca with the same or perhaps lower symmetry of phillipsite-Ca, levyne-Ca and the Ca-rich analogue of merlinoite. In addition, apophyllite-(KF) and/or apophyllite-(KOH), Ca-Ba-carbonates, portlandite and sulphates were present. A new polymorph from the pyrrhotite group, containing three layers of sphalerite-type structure in the unit cell, is reported for the first time. Such a complex association is unique. Most of these minerals are specifically related to hydration processes of: (1) pyrometamorphic metacarbonate/metapelitic rocks (natural analogues of cement clinkers); (2) mineralization between intrusive stocks and slates; and (3) high-calcium, alkaline igneous rocks such as melilitites and foidites as well as carbonatites. The Colle Fabbri outcrop offers an opportunity to study in situ complex crystalline overgrowth and specific crystal chemistry in mineral phases formed in igneous to hydrothermal conditions. 15. Erbium hydride decomposition kinetics. Energy Technology Data Exchange (ETDEWEB) Ferrizz, Robert Matthew 2006-11-01 Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix. 16. Multidimensional simulations of hydrides during fuel rod lifecycle Science.gov (United States) Stafford, D. S. 2015-11-01 In light water reactor fuel rods, waterside corrosion of zirconium-alloy cladding introduces hydrogen into the cladding, where it is slightly soluble. When the solubility limit is reached, the hydrogen precipitates into crystals of zirconium hydride which decrease the ductility of the cladding and may lead to cladding failure during dry storage or transportation events. The distribution of the hydride phase and the orientation of the crystals depend on the history of the spatial temperature and stress profiles in the cladding. In this work, we have expanded the existing hydride modeling capability in the BISON fuel performance code with the goal of predicting both global and local effects on the radial, azimuthal and axial distribution of the hydride phase. We compare results from 1D simulations to published experimental data. We demonstrate the new capability by simulating in 2D a fuel rod throughout a lifecycle that includes irradiation, short-term storage in the spent fuel pool, drying, and interim storage in a dry cask. Using the 2D simulations, we present qualitative predictions of the effects of the inter-pellet gap and the drying conditions on the growth of a hydride rim. 17. Phase composition and structure of aluminum Al-Cu-Si-Sn-Pb alloys Science.gov (United States) Belov, N. A.; Stolyarova, O. O.; Murav'eva, T. I.; Zagorskii, D. L. 2016-06-01 The structure and phase composition of cast and heat treated Al-Cu-Si-Sn-Pb alloys containing 6 wt % Sn, 2 wt % Pb, 0-4 wt % Cu, 0-10 wt % Si have been studied using calculations and experimental methods. Polythermal and isothermal sections are reported, which indicate the existence of two liquid phases. It was found that the low-melting phase is inhomogeneous and consists of individual leadand tin-based particles. 18. Metal hydride air conditioner Institute of Scientific and Technical Information of China (English) YANG; Ke; DU; Ping; LU; Man-qi 2005-01-01 The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs of hydrogen storage alloys, LaNi4.4 Mn0.26 Al0.34 / La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1, LaNi4.61Mn0. 26 Al0.13/La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1 and LaNi4.61 Mn0.26 Al0.13/La0.6 Y0.4 Ni4.8 Mn0. 2, were selected as the working materials for the metal hydride air conditioning system. Studies on the factors affecting the COP of the system showed that higher COP and available hydrogen content need the proper operating temperature and cycling time,large hydrogen storage capacity, flat plateau and small hysterisis of hydrogen alloys, proper original input hydrogen content and mass ratio of the pair of alloys. It also needs small conditioning system was established by using LaNi4.61 Mn0.26 Al0. 13/La0.6 Y0.4 Ni4.8 Mn0.2 alloys as the working materials, which showed that under the operating temperature of 180℃/40℃, a low temperature of 13℃ was reached, with COP =0.38 and Wnet =0.09 kW/kg. 19. Modeling of gamma/gamma-prime phase equilibrium in the nickel-aluminum system Science.gov (United States) Sanchez, J. M.; Barefoot, J. R.; Jarrett, R. N.; Tien, J. K. 1984-01-01 A theoretical model is proposed for the determination of phase equilibrium in alloys, taking into consideration dissimilar lattice parameters. Volume-dependent pair interactions are introduced by means of phenomenological Lennard-Jones potentials and the configurational entropy of the system is treated in the tetrahedron approximation of the cluster variation method. The model is applied to the superalloy-relevant, nickel-rich, gamma/gamma-prime phase region of the Ni-Al phase diagram. The model predicts reasonable values for the lattice parameters and the enthalpy of formation as a function of composition, and the calculated phase diagram closely approximates the experimental diagram. 20. Vapor liquid solid-hydride vapor phase epitaxy (VLS-HVPE) growth of ultra-long defect-free GaAs nanowires: Ab initio simulations supporting center nucleation Energy Technology Data Exchange (ETDEWEB) André, Yamina, E-mail: yamina.andre@univ-bpclermont.fr; Lekhal, Kaddour; Hoggan, Philip; Avit, Geoffrey; Réda Ramdani, M.; Monier, Guillaume; Colas, David; Ajib, Rabih; Castelluci, Dominique; Gil, Evelyne [Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR6602, Institut Pascal, F-63171 Aubière (France); Cadiz, Fabian; Rowe, Alistair; Paget, Daniel [Physique de la matière condensée, Ecole Polytechnique CNRS, Palaiseau (France); Petit, Elodie [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, F-63171 Aubière (France); Leroux, Christine [Université de Toulon, IM2NP, Bât. R, B.P. 20132, 83957 La Garde Cedex (France); CNRS, UMR 7334, 83957 La Garde Cedex (France); Trassoudaine, Agnès [Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR6602, Institut Pascal, F-63171 Aubière (France); Clermont Université, Université d’Auvergne, BP 10448, F-63000 Clermont-Ferrand (France) 2014-05-21 High aspect ratio, rod-like and single crystal phase GaAs nanowires (NWs) were grown by gold catalyst-assisted hydride vapor phase epitaxy (HVPE). High resolution transmission electron microscopy and micro-Raman spectroscopy revealed polytypism-free zinc blende (ZB) NWs over lengths of several tens of micrometers for a mean diameter of 50 nm. Micro-photoluminescence studies of individual NWs showed linewidths smaller than those reported elsewhere which is consistent with the crystalline quality of the NWs. HVPE makes use of chloride growth precursors GaCl of which high decomposition frequency after adsorption onto the liquid droplet catalysts, favors a direct and rapid introduction of the Ga atoms from the vapor phase into the droplets. High influxes of Ga and As species then yield high axial growth rate of more than 100 μm/h. The diffusion of the Ga atoms in the liquid droplet towards the interface between the liquid and the solid nanowire was investigated by using density functional theory calculations. The diffusion coefficient of Ga atoms was estimated to be 3 × 10{sup −9} m{sup 2}/s. The fast diffusion of Ga in the droplet favors nucleation at the liquid-solid line interface at the center of the NW. This is further evidence, provided by an alternative epitaxial method with respect to metal-organic vapor phase epitaxy and molecular beam epitaxy, of the current assumption which states that this type of nucleation should always lead to the formation of the ZB cubic phase. 1. Aluminum-centered tetrahedron-octahedron transition in advancing Al-Sb-Te phase change properties. Science.gov (United States) Xia, Mengjiao; Ding, Keyuan; Rao, Feng; Li, Xianbin; Wu, Liangcai; Song, Zhitang 2015-02-24 Group IIIA elements, Al, Ga, or In, etc., doped Sb-Te materials have proven good phase change properties, especially the superior data retention ability over popular Ge2Sb2Te5, while their phase transition mechanisms are rarely investigated. In this paper, aiming at the phase transition of Al-Sb-Te materials, we reveal a dominant rule of local structure changes around the Al atoms based on ab initio simulations and nuclear magnetic resonance evidences. By comparing the local chemical environments around Al atoms in respective amorphous and crystalline Al-Sb-Te phases, we believe that Al-centered motifs undergo reversible tetrahedron-octahedron reconfigurations in phase transition process. Such Al-centered local structure rearrangements significantly enhance thermal stability of amorphous phase compared to that of undoped Sb-Te materials, and facilitate a low-energy amorphization due to the weak links among Al-centered and Sb-centered octahedrons. Our studies may provide a useful reference to further understand the underlying physics and optimize performances of all IIIA metal doped Sb-Te phase change materials, prompting the development of NOR/NAND Flash-like phase change memory technology. 2. A twist on facial selectivity of hydride reductions of cyclic ketones: twist-boat conformers in cyclohexanone, piperidone, and tropinone reactions. Science.gov (United States) Neufeldt, Sharon R; Jiménez-Osés, Gonzalo; Comins, Daniel L; Houk, K N 2014-12-01 The role of twist-boat conformers of cyclohexanones in hydride reductions was explored. The hydride reductions of a cis-2,6-disubstituted N-acylpiperidone, an N-acyltropinone, and tert-butylcyclohexanone by lithium aluminum hydride and by a bulky borohydride reagent were investigated computationally and compared to experiment. Our results indicate that in certain cases, factors such as substrate conformation, nucleophile bulkiness, and remote steric features can affect stereoselectivity in ways that are difficult to predict by the general Felkin-Anh model. In particular, we have calculated that a twist-boat conformation is relevant to the reactivity and facial selectivity of hydride reduction of cis-2,6-disubstituted N-acylpiperidones with a small hydride reagent (LiAlH4) but not with a bulky hydride (lithium triisopropylborohydride). 3. Geoneutrino and Hydridic Earth model CERN Document Server Bezrukov, Leonid 2013-01-01 Uranium, Thorium and Potassium-40 abundances in the Earth were calculated in the frame of Hydridic Earth model. Terrestrial heat producton from U, Th and K40 decays was calculated also. We must admit the existance of Earth expansion process to understand the obtained large value of terrestrial heat producton. The geoneutrino detector with volume more than 5 kT (LENA type) must be constructed to definitely separate between Bulk Silicat Earth model and Hydridic Earth model. 4. Development of a Two-Phase Model for the Hot Deformation of Highly-Alloyed Aluminum Energy Technology Data Exchange (ETDEWEB) A. J. Beaudoin; J. A. Dantzig; I. M. Robertson; B. E. Gore; S. F. Harnish; H. A. Padilla 2005-10-31 Conventional processing methods for highly alloyed aluminum consist of ingot casting, followed by hot rolling and thermal treatments. Defects result in lost productivity and wasted energy through the need to remelt and reprocess the material. This research centers on developing a fundamental understanding for deformation of wrought 705X series alloys, a key alloy system used in structural airframe applications. The development of damage at grain boundaries is characterized through a novel test that provides initiation of failure while preserving a controlled deformation response. Data from these mechanical tests are linked to computer simulations of the hot rolling process through a critical measure of damage. Transmission electron microscopy provides fundamental insight into deformation at these high working temperatures, and--in a novel link between microscale and macroscale response--the evolution of microstructure (crystallographic orientation) provides feedback for tuning of friction in the hot rolling process. The key product of this research is a modeling framework for the analysis of industrial hot rolling. 5. Shock-induced structural phase transition, plasticity, and brittle cracks in aluminum nitride ceramic. Science.gov (United States) Branicio, Paulo S; Kalia, Rajiv K; Nakano, Aiichiro; Vashishta, Priya 2006-02-17 Atomistic mechanisms of fracture accompanying structural phase transformation (SPT) in AlN ceramic under hypervelocity impact are investigated using a 209 x 10(6) atom molecular-dynamics simulation. The shock wave generated by the impact splits into an elastic wave and a slower SPT wave that transforms the wurtzite structure into the rocksalt phase. The interaction between the reflected elastic wave and the SPT wave front generates nanovoids and dislocations into the wurtzite phase. Nanovoids coalesce into mode I cracks while dislocations give rise to kink bands and mode II cracking. PMID:16606007 6. Thermal and mechanical properties of zirconium hydrides with various hafnium contents International Nuclear Information System (INIS) Zirconium (Zr) hydride is currently expected as a neutron shield material for fast reactors. In order to evaluate safety and economic efficiency of the nuclear reactor, the thermal and mechanical properties of the hydride should be understood. In addition, since chemical properties of Zr and hafnium (Hf) are quite similar, Zr contains a few percent Hf generally. Therefore, it is very important to evaluate the effect of Hf content on the properties of Zr hydride. In the present study, fine bulk samples of δ-phase Zr hydrides with various Hf contents were prepared and their thermal and mechanical properties were investigated. We examined the phase states and the microstructure of the hydrides by means of X-ray diffraction and SEM/EDX analyses. In the temperature range from room temperature to 673 K, the heat capacity and the thermal diffusivity of the hydrides were measured and the thermal conductivity was evaluated. The Vickers hardness and the sound velocity of the hydrides were measured at room temperature, and the elastic modulus was calculated from the measured sound velocity. The effects of temperature and Hf content on the properties of Zr hydrides were studied. (author) 7. Spin Forming of an Aluminum 2219-T6 Aft Bulkhead for the Orion Multi-Purpose Crew Vehicle: Phase II Supplemental Report Science.gov (United States) Piascik, Robert S.; Squire, Michael D.; Domack, Marcia S.; Hoffman, Eric K. 2015-01-01 The principal focus of this project was to assist the Orion Multi-Purpose Crew Vehicle (MPCV) Program in developing a spin forming fabrication process for manufacture of the aft bulkhead of the pressure vessel. The spin forming process will enable a single piece aluminum (Al) 2219 aft bulkhead which will eliminate the current multiple piece welded construction, simplify fabrication, and lead to an enhanced design that will reduce vehicle weight by eliminating welds. Phase I of this assessment explored spin forming the single-piece forward pressure vessel bulkhead from aluminum-lithium 2195. 8. Physics of hydride fueled PWR Science.gov (United States) Ganda, Francesco The first part of the work presents the neutronic results of a detailed and comprehensive study of the feasibility of using hydride fuel in pressurized water reactors (PWR). The primary hydride fuel examined is U-ZrH1.6 having 45w/o uranium: two acceptable design approaches were identified: (1) use of erbium as a burnable poison; (2) replacement of a fraction of the ZrH1.6 by thorium hydride along with addition of some IFBA. The replacement of 25 v/o of ZrH 1.6 by ThH2 along with use of IFBA was identified as the preferred design approach as it gives a slight cycle length gain whereas use of erbium burnable poison results in a cycle length penalty. The feasibility of a single recycling plutonium in PWR in the form of U-PuH2-ZrH1.6 has also been assessed. This fuel was found superior to MOX in terms of the TRU fractional transmutation---53% for U-PuH2-ZrH1.6 versus 29% for MOX---and proliferation resistance. A thorough investigation of physics characteristics of hydride fuels has been performed to understand the reasons of the trends in the reactivity coefficients. The second part of this work assessed the feasibility of multi-recycling plutonium in PWR using hydride fuel. It was found that the fertile-free hydride fuel PuH2-ZrH1.6, enables multi-recycling of Pu in PWR an unlimited number of times. This unique feature of hydride fuels is due to the incorporation of a significant fraction of the hydrogen moderator in the fuel, thereby mitigating the effect of spectrum hardening due to coolant voiding accidents. An equivalent oxide fuel PuO2-ZrO2 was investigated as well and found to enable up to 10 recycles. The feasibility of recycling Pu and all the TRU using hydride fuels were investigated as well. It was found that hydride fuels allow recycling of Pu+Np at least 6 times. If it was desired to recycle all the TRU in PWR using hydrides, the number of possible recycles is limited to 3; the limit is imposed by positive large void reactivity feedback. 9. Novel phases of lithium-aluminum binaries from first-principles structural search Energy Technology Data Exchange (ETDEWEB) Sarmiento-Pérez, Rafael; Cerqueira, Tiago F. T.; Botti, Silvana; Marques, Miguel A. L., E-mail: marques@tddft.org [Institut Lumière Matière (UMR5306) and ETSF, Université Lyon 1-CNRS, Université de Lyon, F-69622 Villeurbanne Cedex (France); Valencia-Jaime, Irais [Institut Lumière Matière (UMR5306) and ETSF, Université Lyon 1-CNRS, Université de Lyon, F-69622 Villeurbanne Cedex (France); Centro de Investigación y Estudios Avanzados del IPN, MX-76230 Querétaro (Mexico); Amsler, Maximilian; Goedecker, Stefan [Department of Physics, Universität Basel, Klingelbergstr. 82, 4056 Basel (Switzerland); Romero, Aldo H. [Physics Department, West Virginia University, Morgantown, West Virginia 26506-6315 (United States) 2015-01-14 Intermetallic Li–Al compounds are on the one hand key materials for light-weight engineering, and on the other hand, they have been proposed for high-capacity electrodes for Li batteries. We determine from first-principles the phase diagram of Li–Al binary crystals using the minima hopping structural prediction method. Beside reproducing the experimentally reported phases (LiAl, Li{sub 3}Al{sub 2}, Li{sub 9}Al{sub 4}, LiAl{sub 3}, and Li{sub 2}Al), we unveil a structural variety larger than expected by discovering six unreported binary phases likely to be thermodynamically stable. Finally, we discuss the behavior of the elastic constants and of the electric potential profile of all Li–Al stable compounds as a function of their stoichiometry. 10. Determination of As(III) and As(V) species in some natural water and food samples by solid-phase extraction on Streptococcus pyogenes immobilized on Sepabeads SP 70 and hydride generation atomic absorption spectrometry. Science.gov (United States) Uluozlu, Ozgur Dogan; Tuzen, Mustafa; Mendil, Durali; Soylak, Mustafa 2010-05-01 The speciation of arsenic(III) and arsenic(V) by using Streptococcus pyogenes immobilized on Sepabeads SP 70 resin has been investigated with solid-phase extraction method. The arsenic levels were determined hydride generation atomic absorption spectrometry (HGAAS) in sample solutions. The procedure presented based on quantitative recoveries of As(III) as >95%. Also the As(V) recoveries were obtained as method. After reduction of As(V) by using KI and ascorbic acid and waiting 1h later, the system was applied to determination of total arsenic. As(V) was found as the difference between the total As and As(III) content. Various experimental parameters such as pH, amount of microorganism, sample volume, etc. were investigated. The capacity of biosorbent for arsenic(III) was calculated as 7.3 mg/g. The preconcentration factor was found as 36. The relative standard deviation was calculated below 8%. Limit of detection was calculated as 13 ng/L. The validation of the presented procedure was tested by analysis of standard reference materials (NIST SRM 1568a Rice floor and GBW 07605 Tea) and obtained fairly compatible results. The procedure was also successfully applied to arsenic speciation and determination of some natural water and food samples. 11. MC-3125 Phase I development. [Aluminum Linear Shaped Charge; HNSII explosive; Uralite 3121S Energy Technology Data Exchange (ETDEWEB) Schmitz, G.T. 1977-10-01 The scope of work outlined as Phase I product development is reported. Specific interest areas are (1) choice of adhesives, (2) compatibility of materials, (3) prototype tooling designs, (4) processes and procedures, and (5) testing. Technical data generated in laboratory studies have been reduced to tabular form and/or charts. 12. Hydride Olefin complexes of tantalum and niobium NARCIS (Netherlands) Klazinga, Aan Hendrik 1979-01-01 This thesis describes investigations on low-valent tantalum and niobium hydride and alkyl complexes, particularly the dicyclopentadienyl tantalum hydride olefin complexes Cp2Ta(H)L (L=olefin). ... Zie: Summary 13. FORMATION REGULARITIES OF PHASE COMPOSITION, STRUCTURE AND PROPERTIES DURING MECHANICAL ALLOYING OF BINARY ALUMINUM COMPOSITES Directory of Open Access Journals (Sweden) F. G. Lovshenko 2015-01-01 Full Text Available The paper presents investigation results pertaining to ascertainment of formation regularities of phase composition and structure during mechanical alloying of binary aluminium composites/substances. The invetigations have been executed while applying a wide range of methods, devices and equipment used in modern material science. The obtained data complement each other. It has been established that presence of oxide and hydro-oxide films on aluminium powder and introduction of surface-active substance in the composite have significant effect on mechanically and thermally activated phase transformations and properties of semi-finished products. Higher fatty acids have been used as a surface active substance.The mechanism of mechanically activated solid solution formation has been identified. Its essence is a formation of specific quasi-solutions at the initial stage of processing. Mechanical and chemical interaction between components during formation of other phases has taken place along with dissolution in aluminium while processing powder composites. Granule basis is formed according to the dynamic recrystallization mechanism and possess submicrocrystal structural type with the granule dimension basis less than 100 nm and the grains are divided in block size of not more than 20 nm with oxide inclusions of 10–20 nm size.All the compounds with the addition of surface-active substances including aluminium powder without alloying elements obtained by processing in mechanic reactor are disperse hardened. In some cases disperse hardening is accompanied by dispersive and solid solution hardnening process. Complex hardening predetermines a high temperature of recrystallization in mechanically alloyed compounds, its value exceeds 400 °C. 14. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities Energy Technology Data Exchange (ETDEWEB) Ford, Denise C.; Cooley, Lance D.; Seidman, David N. 2013-09-01 Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities. 15. Kinetics of Liquid-Phase Hydrogenation of Benzene in a Metal Hydride Slurry System Formed by M1Ni5 and Benzene Institute of Scientific and Technical Information of China (English) 代世耀; 徐国华; 安越; 陈长聘; 陈立新; 王启东 2003-01-01 The kinetics of liquid-phase hydrogenation of benzene in misch metal nickel-five (M1Ni5) and benzene slurry system was studied by investigating the influences of the reaction temperature, pressure, alloy concentration and stirring speed on the mass transfer-reaction processes inside the slurry. The results show that the whole process is controlled by the reaction at the surface of the catalyst. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particles are negligible. The apparent reaction rate is zero order for benzene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model obtained fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of M1Ni5-C6H6 slurry system is 42.16 kJ·mo1-1. 16. The microstructure and hydriding characteristics of high temperature aged U-13 at.%Nb alloy Science.gov (United States) Ji, Hefei; Shi, Peng; Li, Ruiwen; Jiang, Chunli; Yang, Jiangrong; Hu, Guichao 2015-09-01 Niobium as alloying element significantly improves physical and chemical properties of metallic uranium, exhibiting great application potential in uranium alloy materials. The corrosion resistance performance as well as the internal alloy phase structure of uranium-niobium alloy is closely related to aging processes. Microstructure and hydriding characteristics of the 400 °C/9 h + 500 °C/2 h aged uranium-13 at.% niobium alloys (U-13 at.%Nb) were investigated from the point of view of relationship between the microstructure and growth of the hydriding areas. The microstructure, morphology and composition of the alloy phases before and after the hydriding were well characterized by the laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Experimental results indicated that the hydrogen preferentially reacted with the Nb-depleted phase α-like-U to form monolithic β-UH3Nbx, and the alloy microstructure played an important role in hydride growth. 17. Aluminum nitride electro-optic phase shifter for backend integration on silicon. Science.gov (United States) Zhu, Shiyang; Lo, Guo-Qiang 2016-06-13 An AlN electro-optic phase shifter with a parallel plate capacitor structure is fabricated on Si using the back-end complementary metal-oxide-semiconductor technology, which is feasible for multilayer photonics integration. The modulation efficiency (Vπ⋅Lπ product) measured from the fabricated waveguide-ring resonators and Mach-Zehnder Interferometer (MZI) modulators near the 1550-nm wavelength is ∼240 V⋅cm for the transverse electric (TE) mode and ∼320 V⋅cm for the transverse magnetic (TM) mode, from which the Pockels coefficient of the deposited AlN is deduced to be ∼1.0 pm/V for both TE and TM modes. The methods for further modulation efficiency improvement are addressed. 18. The effect of stress state on zirconium hydride reorientation Science.gov (United States) Cinbiz, Mahmut Nedim correlating the finite element stress-state results with the spatial distribution of hydride microstructures observed within the optical micrographs for each sample. Experiments showed that the hydride reorientation was enhanced as the stress biaxiality increased. The threshold stress decreased from 150 MPa to 80 MPa when stress biaxiality ratio increased from uniaxial tension to near-equibiaxial tension. This behavior was also predicted by classical nucleation theory based on the Gibbs free energy of transformation being assisted by the far-field stress. An analysis of in situ X-ray diffraction data obtained during a thermo-mechanical cycle typical of vacuum drying showed a complex lattice-spacing behavior of the hydride phase during the dissolution and precipitation. The in-plane hydrides showed bilinear lattice expansion during heating with the intrinsic thermal expansion rate of the hydrides being observed only at elevated temperatures as they dissolve. For radial hydrides that precipitate during cooling under stress, the spacing of the close-packed {111} planes oriented normal to the maximum applied stress was permanently higher than the corresponding {111} plane spacing in the other directions. This behavior is believed to be a result of a complex stress state within the precipitating plate-like hydrides that induces a strain component within the hydrides normal to its "plate" face (i.e., the applied stress direction) that exceeds the lattice spacing strains in the other directions. During heat-up, the lattice spacing of these same "plate" planes actually contract due to the reversion of the stress state within the plate-like hydrides as they dissolve. The presence of radial hydrides and their connectivity with in-plane hydrides was shown to increase the ductile-to-brittle transition temperature during tensile testing. This behavior can be understood in terms of the role of radial hydrides in promoting the initiation of a long crack that subsequently propagates under 19. Bond and electron beam welding quality control of the aluminum stabilized and reinforced CMS conductor by means of ultrasonic phased-array technology CERN Document Server Neuenschwander, J; Horváth, I L; Luthi, T; Marti, H 2002-01-01 The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the LHC project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. The coils for CNIS are wound of aluminum-stabilized Rutherford type superconductors reinforced with high-strength aluminum alloy. For optimum performance of the conductor a void-free metallic bonding between the high-purity aluminum and the Rutherford type cable as well as between the electron beam welded reinforcement and the high-purity aluminum must be guaranteed. It is the main task of this development work to assess continuously the bond quality over the whole width and the total length of the conductors during manufacture. To achieve this goal we use the ultrasonic phased-array technology. The application of multi- element transducers allows an electronic scanning perpendicular to the direction of production. Such a testing is sufficiently fast in order to allow a continuous a... 20. Development of Hydrogen Storage Tank Systems Based on Complex Metal Hydrides Directory of Open Access Journals (Sweden) Morten B. Ley 2015-09-01 Full Text Available This review describes recent research in the development of tank systems based on complex metal hydrides for thermolysis and hydrolysis. Commercial applications using complex metal hydrides are limited, especially for thermolysis-based systems where so far only demonstration projects have been performed. Hydrolysis-based systems find their way in space, naval, military and defense applications due to their compatibility with proton exchange membrane (PEM fuel cells. Tank design, modeling, and development for thermolysis and hydrolysis systems as well as commercial applications of hydrolysis systems are described in more detail in this review. For thermolysis, mostly sodium aluminum hydride containing tanks were developed, and only a few examples with nitrides, ammonia borane and alane. For hydrolysis, sodium borohydride was the preferred material whereas ammonia borane found less popularity. Recycling of the sodium borohydride spent fuel remains an important part for their commercial viability. 1. Optimization of o-phtaldialdehyde/2-mercaptoethanol postcolumn reaction for the hydrophilic interaction liquid chromatography determination of memantine utilizing a silica hydride stationary phase. Science.gov (United States) Douša, Michal; Pivoňková, Veronika; Sýkora, David 2016-08-01 A rapid procedure for the determination of memantine based on hydrophilic interaction chromatography with fluorescence detection was developed. Fluorescence detection after postcolumn derivatization with o-phtaldialdehyde/2-mercaptoethanol was performed at excitation and emission wavelengths of 345 and 450 nm, respectively. The postcolumn reaction conditions such as reaction temperature, derivatization reagent flow rate, and reagents concentration were studied due to steric hindrance of amino group of memantine. The derivatization reaction was applied for the hydrophilic interaction liquid chromatography method which was based on Cogent Silica-C stationary phase with a mobile phase consisting of a mixture of 10 mmol/L citric acid and 10 mmol/L o-phosphoric acid (pH 6.0) with acetonitrile using an isocratic composition of 2:8 v/v. The benefit of the reported approach consists in a simple sample pretreatment and a quick and sensitive hydrophilic interaction chromatography method. The developed method was validated in terms of linearity, accuracy, precision, and selectivity according to the International Conference on Harmonisation guidelines. The developed method was successfully applied for the analysis of commercial memantine tablets. 2. Formation and physical properties of uranium hydride under conditions relevant to metallic fuel and nuclear waste storage Science.gov (United States) Orr, Robin; Godfrey, Hugh; Broan, Chris; Goddard, Dave; Woodhouse, Guy; Durham, Peter; Diggle, Andrew; Bradshaw, John 2016-08-01 The formation of uranium hydride is recognised as a hazard during the storage of uranium metal owing to its potentially pyrophoric properties. This study has assessed the influence of water vapour on the potential for uranium hydride to form at low temperatures and shows that it increases the duration of the induction period but does not necessarily prevent uranium hydride formation and also does not significantly change the reaction rate with hydrogen. It is further shown that the α-UH3 fraction in the uranium hydride gradually increases at decreasing temperatures and is likely to be the dominant phase formed under typical storage conditions. Particle morphology and specific surface area of uranium hydride prepared between 30 °C and 200 °C have also been characterised but show only modest variation compared with the phase composition. 3. Direct hydride derivatization of methyl- and ethylmercury chlorides in aqueous solution with KBH4 Institute of Scientific and Technical Information of China (English) 2000-01-01 A convenient hydride derivatization procedure of methyl-and ethylmercury chlorides to volatile hydrides was reported. In sealed vials methylmercury and ethylmercury compounds in acidic aqueous solutions were converted into their volatile forms by the reaction with potassium tetrahydroborate(KBH4) and elvolved to the headspace of the vials. The gaseous analytes in the headspace were extracted and concentrated by solid phase microextraction(SPME) and injected into gas chromatography (GC) for separation and identified by mass selective detector(MS). 4. The thermodynamics of hydride precipitation: the importance of entropy, enthalpy and disorder OpenAIRE Lumley, S. C.; Grimes, R. W.; Murphy, S. T.; Burr, P. A.; Chroneos, A.; Chard-Tucke, P. R.; Wenman, M. R. 2014-01-01 The thermodynamics of H/{\\alpha}-Zr solid solution and zirconium hydride phases were studied using density functional theory. Disorder in {\\zeta}, {\\gamma} and {\\delta} hydrides and solid solutions were modelled using a statistically significant number of randomly generated structures in combination with special quasi-random structures and solid solutions with a range of concentrations. This is used in conjunction with a calculation of thermodynamic parameters of the system, including the tem... 5. Sensitive determination of As (III) and As (V) by magnetic solid phase extraction with Fe@polyethyleneimine in combination with hydride generation atomic fluorescence spectrometry. Science.gov (United States) Zhou, Qingxiang; Zheng, Zhenwen; Xiao, Junping; Fan, Huili 2016-08-15 The magnetic nanomaterial Fe@polyethyleneimine (Fe@PEI) was successfully synthesized and used as an effective adsorbent material for magnetic solid phase extraction(MSPE) of As(III) and As(V) from water samples. Fe@SiO2 nanoparticles were prepared by one pot synthetic method using a borohydride reduction method, then modified with (3-chloropropyl)trimethoxysilane to obtain Fe@SiO2-Cl by chloropropylation, which was reacted with PEI to achieve Fe@polyethyleneimine (Fe@PEI). The microstructure and morphology of Fe@PEI were characterized by transmission electron microscoscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The experimental results showed that Fe@PEI demonstrated excellent adsorption for As(III) and As(V). Based on this fact, the determination method for these two arsenic species earned good limits of detection (LODs) of 0.002μgL(-1) and wide calibration curves in the concentration range from 0.008 to 0.2μgL(-1). The precisions of As (III) and As (V)were 1.95% and 2.55% (RSD, n=6), respectively. The proposed method was validated with real samples and the spiked recoveries were in the range of 82.7-98.3% and the accuracies were in the range of 2-13.3%. The results demonstrated that the developed MSPE method had good advantages such as simplicity, rapid separation, low cost, easy to reuse and high-quality analytical performances, which made it attractive for rapid and efficient extraction of inorganic arsenic species in the environmental water samples. PMID:27260453 6. Effect of lattice defects and temperature transition rates on the deuteride (hydride) particle morphology and phase transformation thermal hysteresis in niobium International Nuclear Information System (INIS) Small-angle neutron scattering (SANS) measurements have been performed to investigate deuteride particle morphology and the phase transformation temperature hysteresis in low-concentration Nb-D alloys. Deformation either by cold rolling and or by previous deuteride cycling induced a coarse deuteride particle distribution. This observation is attributed to a more heterogeneous precipitation process facilitated by the dislocation defects and/or dislocation substructure. Deuteride precipitation in the deformed samples was observed immediately upon crossing the incoherent solvus during temperature reduction, again consistent with dislocation-aided nucleation. Deuteride dissolution was observed at the very onset of heating for the cold-rolled material, an observation unique among the samples characterized here. This is attributed to the availability of elastic accommodation energy for deuteride particles embedded in the severely work-hardened host matrix. In other words, the elastic energy assists dissolution, consistent with a theoretical model developed by Puls (1984 Acta Metall. 32 1259-69). The effect of temperature reduction transition rates was also investigated. Rapid, direct cooling (at 2-3 K min-1) resulted in a much finer deuteride particle distribution - a factor of 200 increase in the particle number density and a factor of ten reduction in characteristic particle size compared to well annealed single crystal Nb. The thermal hysteresis was also affected by the temperature transition rates, with a significant reduction of the hysteresis for the slowest cooling rates. This implies that at least part of the recorded hysteresis in the well annealed material is dependent on the temperature transition rate. (author) 7. On the chemistry of hydrides of N atoms and O$^+$ions CERN Document Server Awad, Zainab; Williams, David A 2016-01-01 Previous work by various authors has suggested that the detection by Herschel/HIFI of nitrogen hydrides along the low density lines of sight towards G10.6-0.4 (W31C) cannot be accounted for by gas-phase chemical models. In this paper we investigate the role of surface reactions on dust grains in diffuse regions, and we find that formation of the hydrides by surface reactions on dust grains with efficiency comparable to that for H$_2$formation reconciles models with observations of nitrogen hydrides. However, similar surface reactions do not contribute significantly to the hydrides of O$^+$ions detected by Herschel/HIFI present along many sight lines in the Galaxy. The O$^+hydrides can be accounted for by conventional gas-phase chemistry either in diffuse clouds of very low density with normal cosmic ray fluxes or in somewhat denser diffuse clouds with high cosmic ray fluxes. Hydride chemistry in dense dark clouds appears to be dominated by gas-phase ion-molecule reactions. 8. Control Preparation of Nano γ Phase Aluminum Oxide by Explosive Temperature%爆温控制合成γ型纳米氧化铝 Institute of Scientific and Technical Information of China (English) 李瑞勇; 李晓杰; 闫鸿浩 2011-01-01 本文旨在通过改变混合炸药的爆温来控制爆轰合成的纳米氧化铝的晶型.根据研究方案,采用600 g硝酸铝粉末和400 g炸药黑索金粉末为原材料,通过搅拌把两者均匀混合配制出混合炸药.经过计算该粉状混合炸药的理论爆温约为945℃,该温度接近于低温稳定的7型氧化铝生成和存在的温度区间,所以该混合炸药发生爆轰反应时应该产生γ型纳米氧化铝.为了验证理论分析,将该混合炸药放在直径为3 m的专用爆炸罐里面进行了爆轰反应实验.利用X射线衍射仪(XRD)和透射电子显微镜(TEM)对收集到的爆轰产物进行了检测.检测结果表明爆轰产物确实是y型纳米氧化铝,氧化铝颗粒为标准的球形,颗粒尺寸约为20 nm.因此,可以通过理论计算改变混合炸药的爆温来控制纳米氧化铝的晶型.%The phase of nano aluminum oxide prepared by detonation synthesis was controlled by changing the explosive temperature of the mixed explosion. According to the research scheme, the mixed explosion was made through uniformly mixing 600 g aluminum nitrate powder with 400 g explosive hexogen.The theoretical explosive temperature of the mixed explosion was 945 ℃ by theoretical calculation, which was close to the temperature interval of formation and existence of γ phase aluminum oxide. Therefore,nano γphase aluminum oxide should be prepared through detonation of the mixed explosion. In order to prove the theoretical presumption, detonation experiment was conducted in a special spherical tank with 3 m diameter and the explosion product was characterized by transmission electron microscope (TEM) and X-ray diffraction (XRD). The results indicate that the product is nano γ phase aluminum oxide actually and the granule of aluminum oxide is spherical, with the particle dimension of about 20 nm. It is thus verified that the phase of aluminum oxide can be controlled by changing the explosive temperature of the mixed 9. Anodematerials for Metal Hydride Batteries DEFF Research Database (Denmark) Jensen, Jens Oluf 1997-01-01 This report describes the work on development of hydride forming alloys for use as electrode materials in metal hydride batteries. The work has primarily been concentrated on calcium based alloys derived from the compound CaNi5. This compound has a higher capacity compared with alloys used in today...... was developed. The parameters milling time, milling intensity, number of balls and form of the alloying metals were investigated. Based on this a final alloying technique for the subsequent preparation of electrode materials was established. The technique comprises milling for 4 hours twice possibly followed...... by annealing at 700°C for 12 hours. The alloys appeared to be nanocrystalline with an average crystallite size around 10 nm before annealing. Special steel containers was developed for the annealing of the metal powders in inert atmosphere. The use of various annealing temperatures was investigated... 10. Nanostructured, complex hydride systems for hydrogen generation Directory of Open Access Journals (Sweden) Robert A. Varin 2015-02-01 Full Text Available Complex hydride systems for hydrogen (H2 generation for supplying fuel cells are being reviewed. In the first group, the hydride systems that are capable of generating H2 through a mechanical dehydrogenation phenomenon at the ambient temperature are discussed. There are few quite diverse systems in this group such as lithium alanate (LiAlH4 with the following additives: nanoiron (n-Fe, lithium amide (LiNH2 (a hydride/hydride system and manganese chloride MnCl2 (a hydride/halide system. Another hydride/hydride system consists of lithium amide (LiNH2 and magnesium hydride (MgH2, and finally, there is a LiBH4-FeCl2 (hydride/halide system. These hydride systems are capable of releasing from ~4 to 7 wt.% H2 at the ambient temperature during a reasonably short duration of ball milling. The second group encompasses systems that generate H2 at slightly elevated temperature (up to 100 °C. In this group lithium alanate (LiAlH4 ball milled with the nano-Fe and nano-TiN/TiC/ZrC additives is a prominent system that can relatively quickly generate up to 7 wt.% H2 at 100 °C. The other hydride is manganese borohydride (Mn(BH42 obtained by mechano-chemical activation synthesis (MCAS. In a ball milled (2LiBH4 + MnCl2 nanocomposite, Mn(BH42 co-existing with LiCl can desorb ~4.5 wt.% H2 at 100 °C within a reasonable duration of dehydrogenation. Practical application aspects of hydride systems for H2 generation/storage are also briefly discussed. 11. Inhibited solid propellant composition containing beryllium hydride Science.gov (United States) Thompson, W. W. (Inventor) 1978-01-01 An object of this invention is to provide a composition of beryllium hydride and carboxy-terminated polybutadiene which is stable. Another object of this invention is to provide a method for inhibiting the reactivity of beryllium hydride toward carboxy-terminated polybutadiene. It was found that a small amount of lecithin inhibits the reaction of beryllium hydride with the acid groups in carboxy terminated polybutadiene. 12. Crystal structure of gold hydride International Nuclear Information System (INIS) Highlights: • Volume expansion of metal hydrides is due to the increase in the s-band filling. • AuH structure is similar to that of Hg having one more s electron compared to Au. • Structure stability of both Hg and AuH is governed by the Hume-Rothery rule. - Abstract: A number of transition metal hydrides with close-packed metal sublattices of fcc or hcp structures with hydrogen in octahedral interstitial positions were obtained by the high-pressure-hydrogen technique described by Ponyatovskii et al. (1982). In this paper we consider volume increase of metals by hydrogenation and possible crystal structure of gold hydride in relation with the structure of mercury, the nearest neighbor of Au in the Periodic table. Suggested structure of AuH has a basic tetragonal body-centered cell that is very similar to the mercury structure Hg-t I 2. The reasons of stability for this structure are discussed within the model of Fermi sphere–Brillouin zone interactions 13. Crystal structure of gold hydride Energy Technology Data Exchange (ETDEWEB) Degtyareva, Valentina F., E-mail: degtyar@issp.ac.ru 2015-10-05 Highlights: • Volume expansion of metal hydrides is due to the increase in the s-band filling. • AuH structure is similar to that of Hg having one more s electron compared to Au. • Structure stability of both Hg and AuH is governed by the Hume-Rothery rule. - Abstract: A number of transition metal hydrides with close-packed metal sublattices of fcc or hcp structures with hydrogen in octahedral interstitial positions were obtained by the high-pressure-hydrogen technique described by Ponyatovskii et al. (1982). In this paper we consider volume increase of metals by hydrogenation and possible crystal structure of gold hydride in relation with the structure of mercury, the nearest neighbor of Au in the Periodic table. Suggested structure of AuH has a basic tetragonal body-centered cell that is very similar to the mercury structure Hg-t I 2. The reasons of stability for this structure are discussed within the model of Fermi sphere–Brillouin zone interactions. 14. Hydrogen storage materials and metal hydride-Ni batteries International Nuclear Information System (INIS) The hydrogen storage alloy is the key active material in metal hydride-Ni (MH-Ni) batteries. A brief review of hydrogen storage negative electrode materials including misch-nickel-based alloys, Laves phase alloys, magnesium-based alloys, vanadium-based solid solutions and nanotubes is presented. Current problems that need to be solved are mentioned. In addition, recent developments of MH/Ni-batteries with high power and energy are introduced 15. Surface treatments toward obtaining clean GaN(0 0 0 1) from commercial hydride vapor phase epitaxy and metal-organic chemical vapor deposition substrates in ultrahigh vacuum International Nuclear Information System (INIS) We studied processes of cleaning GaN(0 0 0 1) surfaces on four different types of wafers: two types were hydride vapor phase epitaxy (HVPE) free-standing substrates and two types were metal-organic chemical vapor deposition (MOCVD) films grown on these HVPE substrates and prepared by annealing and/or Ar ion sputtering in ultra high vacuum. We observed the surfaces through treatments using in situ low-energy electron diffraction (LEED), reflection high-energy electron diffraction (RHEED), scanning tunneling microscopy (STM), and Auger electron spectroscopy, and also using ex situ temperature programmed desorption, X-ray photoelectron spectroscopy, X-ray diffraction, and secondary ion mass spectrometry. For HVPE samples, we obtained relatively clean surfaces under optimized three-step annealing conditions (200 deg. C for 12 h + 400 deg. C for 1 h + 500 deg. C for 5 min) without sputtering, after which the surface contamination of oxide and carbide was reduced to ∼20% of that before annealing. Clear GaN(0 0 0 1)1x1 patterns were obtained by LEED and RHEED. STM images showed flat terraces of ∼10 nm size and steps of ∼0.5 nm height. Upon annealing the HVPE-GaN samples at a much higher temperature (>550 deg. C), three-dimensional (3D) islands with facets were formed and the surface stoichiometry was broken down with the desorption of nitrogen in the form of ammonia, since the samples include hydrogen as an impurity. Ar+ sputtering was effective for removing surface contamination, however, postannealing could not recover the surface roughness but promoted the formation of 3D islands on the surface. For MOCVD/HVPE homoepitaxial samples, the surfaces are terminated by hydrogen and the as-introduced samples showed a clear 1x1 structure. Upon annealing at 500-600 deg. C, the surface hydrogen was removed and a 3x3 reconstruction structure partially appeared, although a 1x1 structure was dominant. We summarize the structure differences among the samples under the same 16. Study on Non-interlayer Liquid Phase Diffusion Bonding for SiCp/ZL101 Aluminum Matrix Composite Institute of Scientific and Technical Information of China (English) Wei GUO; Jitai NIU; Jinfan ZHAI; Changli WANG; Jie YU; Guangtao ZHOU 2003-01-01 Through the vacuum diffusion bonding for SiCp/ZLl01 aluminum matrix composite, the influence of bonding parameters on the joint properties was reported, with the aim to obtain optimal bonding parameters. The microstructureof joints was analyzed by means o 17. Metal Hydrides for Rechargeable Batteries Energy Technology Data Exchange (ETDEWEB) Valoeen, Lars Ole 2000-03-01 Rechargeable battery systems are paramount in the power supply of modern electronic and electromechanical equipment. For the time being, the most promising secondary battery systems for the future are the lithium-ion and the nickel metal hydride (NiMH) batteries. In this thesis, metal hydrides and their properties are described with the aim of characterizing and improving those. The thesis has a special focus on the AB{sub 5} type hydrogen storage alloys, where A is a rare earth metal like lanthanum, or more commonly misch metal, which is a mixture of rare earth metals, mainly lanthanum, cerium, neodymium and praseodymium. B is a transition metal, mainly nickel, commonly with additions of aluminium, cobalt, and manganese. The misch metal composition was found to be very important for the geometry of the unit cell in AB{sub 5} type alloys, and consequently the equilibrium pressure of hydrogen in these types of alloys. The A site substitution of lanthanum by misch metal did not decrease the surface catalytic properties of AB{sub 5} type alloys. B-site substitution of nickel with other transition elements, however, substantially reduced the catalytic activity of the alloy. If the internal pressure within the electrochemical test cell was increased using inert argon gas, a considerable increase in the high rate charge/discharge performance of LaNi{sub 5} was observed. An increased internal pressure would enable the utilisation of alloys with a high hydrogen equivalent pressure in batteries. Such alloys often have favourable kinetics and high hydrogen diffusion rates and thus have a potential for improving the high current discharge rates in metal hydride batteries. The kinetic properties of metal hydride electrodes were found to improve throughout their lifetime. The activation properties were found highly dependent on the charge/discharge current. Fewer charge/discharge cycles were needed to activate the electrodes if a small current was used instead of a higher 18. The progress of nanocrystalline hydride electrode materials International Nuclear Information System (INIS) This paper reviews research at the Institute of Materials Science and Engineering, Poznan University of Technology, on the synthesis of nanocrystalline hydride electrode materials. Nanocrystalline materials have been synthesized by mechanical alloying (MA) followed by annealing. Examples of the materials include TiFe-, ZrV2-, LaNi5 and Mg2Ni-type phases. Details on the process used and the enhancement of properties due to the nanoscale structures are presented. The synthesized alloys were used as negative electrode materials for Ni-MH battery. The properties of hydrogen host materials can be modified substantially by alloying to obtain the desired storage characteristics. For example, it was found that the respective replacement of Fe in TiFe by Ni and/or by Cr, Co, Mo improved not only the discharge capacity but also the cycle life of these electrodes. The hydrogen storage properties of nanocrystalline ZrV2- and LaNi5-type powders prepared by mechanical alloying and annealing show no big difference with those of melt casting (polycrystalline) alloys. On the other hand, a partial substitution of Mg by Mn or Al in Mg2Ni alloy leads to an increase in discharge capacity, at room temperature. Furthermore, the effect of the nickel and graphite coating on the structure of some nanocrystalline alloys and the electrodes characteristics were investigated. In the case of Mg2Ni-type alloy mechanical coating with graphite effectively reduced the degradation rate of the studied electrode materials. The combination of a nanocrystalline TiFe-, ZrV2- and LaNi5-type hydride electrodes and a nickel positive electrode to form a Ni-MH battery, has been successful. (authors) 19. Behaviour of aluminum foam under fire conditions Directory of Open Access Journals (Sweden) J. Grabian 2008-07-01 Full Text Available Taking into account fire-protection requirements it is advantageous for aluminum foam, after melting at a temperature considerably exceeding the melting point, to have a structure of discontinuous suspension of solid inclusions to liquid metal instead of liquid consistency. Continuity of the suspension depends on the solid phase content. The boundary value of the phase determined by J. Śleziona, above which the suspension becomes discontinuous, is provided by the formula (1. Figure 1 presents the relationship graphically. Boundary values of the vs content resulting from the above relationship is too low, taking into account the data obtained from the technology of suspension composites [4]. Therefore, based on the structure assumed for the suspension shown in Figure 2 these authors proposed another way of determining the contents, the value of which is determined by the relationship (3 [5].For purposes of the experimental study presented in the paper two foams have been molten: a commercially available one, made by aluminum foaming with titanium hydride, and a foam manufactured in the Marine Materials Plant of the Maritime University of Szczecin by blowing the AlSi7 +20% SiC composite with argon. Macrophotographs of foam cross-sections are shown in Figure 3. The foams have been molten in the atmosphere of air at a temperature of 750ºC. The products of melting are presented in Figure 4. It appears that molten aluminum foam may have no liquid consistency, being unable to flow, which is a desired property from the point of view of fire-protection. The above feature of the molten foam results from the fact that it may be a discontinuous suspension of solid particles in a liquid metal. The suspended particles may be solid particles of the composite that served for making the foam or oxide membranes formed on extended metal surface of the bubbles included in the foam. The desired foam ability to form a discontinuous suspension after melting may be 20. Predicting formation enthalpies of metal hydrides DEFF Research Database (Denmark) Andreasen, A. 2004-01-01 In order for the hydrogen based society viz. a society in which hydrogen is the primary energy carrier to become realizable an efficient way of storing hydrogen is required. For this purpose metal hydrides are serious candidates. Metal hydrides are formedby chemical reaction between hydrogen and ... 1. Fracture mechanism of TiAl intermetallics caused by hydride and atomic hydrogen Institute of Scientific and Technical Information of China (English) 高克玮; 王燕斌; 林志; 乔利杰; 褚武扬 1999-01-01 Hydrogen embrittlement （HE） of TiAl intermetallics was studied at room temperature. The results showed that there were two forms of HE in TiAl intermetallics, i.e. hydride HE and atomic HE. Most of hydrogen in TiAl intermetallics was transformed into hydrides at room temperature. The hydride exists as （TiAl）Hx for a low hydrogen concentration while it exists in several forms for a higher hydrogen concentration. Stress intensity factor KIC decreased with increase in hydride concentration. KIC decreased further when TiAl intermetallics were charged cathodically with hydrogen in 1 mol/L H2SO4 solution. Stress intensity factor during hydrogen charging KIH was about 50％ KIC. 20％ of the decrease was caused by hydrides while 30％ was caused by atomic hydrogen. Mechanism of HE caused hydrides was the same as any other second phase in nature. Delayed fracture caused by atomic hydrogen resulted from hydrogen induced local plastic deformation. 2. Hydrogen-storing hydride complexes Science.gov (United States) Srinivasan, Sesha S.; Niemann, Michael U.; Goswami, D. Yogi; Stefanakos, Elias K. 2012-04-10 A ternary hydrogen storage system having a constant stoichiometric molar ratio of LiNH.sub.2:MgH.sub.2:LiBH.sub.4 of 2:1:1. It was found that the incorporation of MgH.sub.2 particles of approximately 10 nm to 20 nm exhibit a lower initial hydrogen release temperature of 150.degree. C. Furthermore, it is observed that the particle size of LiBNH quaternary hydride has a significant effect on the hydrogen sorption concentration with an optimum size of 28 nm. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160.degree. C. and the other around 300.degree. C., with the main hydrogen release temperature reduced from 310.degree. C. to 270.degree. C., while hydrogen is first reversibly released at temperatures as low as 150.degree. C. with a total hydrogen capacity of 6 wt. % to 8 wt. %. Detailed thermal, capacity, structural and microstructural properties have been demonstrated and correlated with the activation energies of these materials. 3. Gas-Phase Partial Oxidation of Lignin to Carboxylic Acids over Vanadium Pyrophosphate and Aluminum-Vanadium-Molybdenum. Science.gov (United States) Lotfi, Samira; Boffito, Daria C; Patience, Gregory S 2015-10-26 Lignin is a complex polymer that is a potential feedstock for aromatic compounds and carboxylic acids by cleaving the β-O-4 and 5-5' linkages. In this work, a syringe pump atomizes an alkaline solution of lignin into a catalytic fluidized bed operating above 600 K. The vanadium heterogeneous catalysts convert all the lignin into carboxylic acids (up to 25 % selectivity), coke, carbon oxides, and hydrogen. Aluminum-vanadium-molybdenum mostly produced lactic acid (together with formic acid, acrylic acid, and maleic anhydride), whereas the vanadium pyrophosphate catalyst produced more maleic anhydride. PMID:26361086 4. Experimental reproducibility analysis in DU hydriding Energy Technology Data Exchange (ETDEWEB) Koo, Daeseo; Park, Jongcheol; Chung, Hongsuk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of) 2014-10-15 A storage and delivery system (SDS) is used for storing hydrogen isotopes as a metal hydride form. The rapid hydriding of tritium is very important not only for safety reasons but also for the economic design and operation of the SDS. For the storage, supply, and recovery of hydrogen isotopes, depleted uranium (DU) has been extensively proposed. To develop nuclear fusion technology, it will be necessary to store and supply hydrogen isotopes needed for Tokamak operation. The experimental reproducibility of bed temperature on DU hydriding was also analyzed. The experimental reproducibility of apparatus was acceptable for all the experiments. The experimental reproducibility of tank pressure on DU hydriding was analyzed. As the hydriding performs, the tank pressure showed decreasing trend. The experimental reproducibility of bed temperature on DU hydriding was also analyzed. As the hydriding performs, the bed temperatures increased up to maximum temperature with exothermic reaction and then they showed decreasing trend. The experimental reproducibility of apparatus was acceptable for all the experiments. 5. Synthesis and Characterization of Metal Hydride/Carbon Aerogel Composites for Hydrogen Storage Directory of Open Access Journals (Sweden) Kuen-Song Lin 2012-01-01 Full Text Available Two materials currently of interest for onboard lightweight hydrogen storage applications are sodium aluminum hydride (NaAlH4, a complex metal hydride, and carbon aerogels (CAs, a light porous material connected by several spherical nanoparticles. The objectives of the present work have been to investigate the synthesis, characterization, and hydrogenation behavior of Pd-, Ti- or Fe-doped CAs, NaAlH4, and MgH2 nanocomposites. The diameters of Pd nanoparticles onto CA’s surface and BET surface area of CAs were 3–10 nm and 700–900 m2g−1, respectively. The H2 storage capacity of metal hydrides has been studied using high-pressure TGA microbalance and they were 4.0, 2.7, 2.1, and 1.2 wt% for MgH2-FeTi-CAs, MgH2-FeTi, CAs-Pd, and 8 mol% Ti-doped NaAlH4, respectively, at room temperature. Carbon aerogels with higher surface area and mesoporous structures facilitated hydrogen diffusion and adsorption, which accounted for its extraordinary hydrogen storage phenomenon. The hydrogen adsorption abilities of CAs notably increased after inclusion of metal hydrides by the “hydrogen spillover” mechanisms. 6. Effects of Hf on thermal and mechanical properties of Zr hydrides International Nuclear Information System (INIS) The polycrystalline fine bulk samples of δ-phase Zr hydrides with various Hf contents were prepared and their thermal and mechanical properties were investigated. In the temperature range from room temperature to 973 K, the phase states were examined by high-temperature X-ray diffraction and thermogravimetry/differential thermal analyses. In the temperature range from room temperature to 673 K, the coefficient of linear thermal expansion, specific heat capacity, and thermal conductivity were evaluated. The Vickers hardness and sound velocity were measured at room temperature, and the elastic modulus was evaluated. The effects of Hf on the thermal and mechanical properties of Zr hydrides were studied. (author) 7. Pressure-driven formation and stabilization of superconductive chromium hydrides Science.gov (United States) Yu, Shuyin; Jia, Xiaojing; Frapper, Gilles; Li, Duan; Oganov, Artem R.; Zeng, Qingfeng; Zhang, Litong 2015-01-01 Chromium hydride is a prototype stoichiometric transition metal hydride. The phase diagram of Cr-H system at high pressures remains largely unexplored due to the challenges in dealing with the high activation barriers and complications in handing hydrogen under pressure. We have performed an extensive structural study on Cr-H system at pressure range 0 ∼ 300 GPa using an unbiased structure prediction method based on evolutionary algorithm. Upon compression, a number of hydrides are predicted to become stable in the excess hydrogen environment and these have compositions of Cr2Hn (n = 2–4, 6, 8, 16). Cr2H3, CrH2 and Cr2H5 structures are versions of the perfect anti-NiAs-type CrH with ordered tetrahedral interstitial sites filled by H atoms. CrH3 and CrH4 exhibit host-guest structural characteristics. In CrH8, H2 units are also identified. Our study unravels that CrH is a superconductor at atmospheric pressure with an estimated transition temperature (T c) of 10.6 K, and superconductivity in CrH3 is enhanced by the metallic hydrogen sublattice with T c of 37.1 K at 81 GPa, very similar to the extensively studied MgB2. PMID:26626579 8. Hydrogen adsorption on palladium and palladium hydride at 1 bar DEFF Research Database (Denmark) Johansson, Martin; Skulason, Egill; Nielsen, Gunver; 2010-01-01 strongly to Pd hydride than to Pd. The activation barrier for desorption at a H coverage of one mono layer is slightly lower on Pd hydride, whereas the activation energy for adsorption is similar on Pd and Pd hydride. It is concluded that the higher sticking probability on Pd hydride is most likely caused...... by a slightly lower equilibrium coverage of H, which is a consequence of the lower heat of adsorption for H on Pd hydride.... 9. Hydride heat pump with heat regenerator Science.gov (United States) Jones, Jack A. (Inventor) 1991-01-01 A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature. 10. Aluminum Hydroxide Science.gov (United States) ... penicillamine (Cuprimine, Depen), prednisone (Deltasone, Orasone), products containing iron, tetracycline (Sumycin, Tetracap, and others), ticlopidine (Ticlid), and vitamins.be aware that aluminum hydroxide may interfere with other medicines, making them less ... 11. Geoneutrino and Hydridic Earth model. Version 2 OpenAIRE Bezrukov, Leonid 2013-01-01 Uranium, Thorium and Potassium-40 abundances in the Earth were calculated in the frame of Hydridic Earth model. Terrestrial heat producton from U, Th and K40 decays was calculated also. We must admit the existance of Earth expansion process to understand the obtained large value of terrestrial heat producton. The geoneutrino detector with volume more than 5 kT (LENA type) must be constructed to definitely separate between Bulk Silicat Earth model and Hydridic Earth model. In second version of... 12. Atomistic Potentials for Palladium-Silver Hydrides OpenAIRE Hale, L. M.; Wong, B. M.; Zimmerman, J. A.; Zhou, X. 2013-01-01 New EAM potentials for the ternary palladium-silver-hydrogen system are developed by extending a previously developed palladium-hydrogen potential. The ternary potentials accurately capture the heat of mixing and structural properties associated with solid solution alloys of palladium-silver. Stable hydrides are produced with properties that smoothly transition across the compositions. Additions of silver to palladium are predicted to alter the properties of the hydrides by decreasing the mis... 13. gamma-Zr-Hydride Precipitate in Irradiated Massive delta- Zr-Hydride DEFF Research Database (Denmark) Warren, M. R.; Bhattacharya, D. K. 1975-01-01 During examination of A Zircaloy-2-clad fuel pin, which had been part of a test fuel assembly in a boiling water reactor, several regions of severe internal hydriding were noticed in the upper-plenum end of the pin. Examination of similar fuel pins has shown that hydride of this type is caused... 14. Formation and Compression Behavior of Two-Phase Bulk Metallic Glasses with a Minor Addition of Aluminum Institute of Scientific and Technical Information of China (English) ZONG Hai-Tao; MA Ming-Zhen; ZHANG Xin-Yu; QI Li; LI Gong; JING Qin; LIU Ri-Ping 2011-01-01 A remarkable enhancement in room-temperature compressive deformability is realized by the minor-addition of 1.5 at. % Al in ZrTi-based bulk metallic glass.Two amorphous phases are observed by transmission electron microscopy in the Al-containing alloys and this explains the improvement of compression deformability. The studies suggest that phase separation might occur in glass forming alloys with a negative enthalpy of mixing. 15. Metastable phases in the aluminum-germanium alloy system: Synthesis by mechanical alloying and pressure induced transformations Energy Technology Data Exchange (ETDEWEB) Yvon, P. 1994-01-01 Al and Ge form a simple equilibrium eutectic with limited mutual solubility and no intermetallic intermediate phases. We used a regular solution approach to model effects of pressure on Al-Ge. Effects of pressure are to extend solubility of Ge in Al, to displace the eutectic composition towards the Ge rich side, and to slightly decrease the eutectic temperature. We designed thermobaric treatments to induce crystal-to-glass transformations in fine grain mixtures of Al and Ge. We used Merrill-Bassett diamond anvil cells to perform experiments at high pressures. We built an x-ray apparatus to determine the structure of alloys at pressure and from cryogenic temperatures to 400C. Two-phase Al-Ge samples with fine microstructures were prepared by splat-quenching and mechanical alloying. We observed a crystal-to-glass transformation at about 80 kbar. The amorphous phase formed was metastable at ambient temperature after pressure release. This was confirmed by TEM. The amorphous phase obtained by pressurization was found to have a liquid-like structure and was metallic. In the TEM samples we also observed the presence of a second amorphous phase formed upon release of the pressure. This second phase had a tetrahedrally-bonded continuous random network structure, similar to that of semi-conducting amorphous germanium. 16. Fourier-Domain Analysis of Hydriding Kinetics Using Pneumato-Chemical Impedance Spectroscopy OpenAIRE Millet, P.; C. Decaux; R. Ngameni; Guymont, M. 2007-01-01 Analysis of phase transformation processes observed in hydrogen absorbing materials (pure metals, alloys, or compounds) is still a matter of active research. Using pneumato-chemical impedance spectroscopy (PIS), it is now possible to analyze the mechanism of hydriding reactions induced by the gas phase. Experimental impedance diagrams, measured on activated LaNi5 in single- and two-phase domains, are reported in this paper. It is shown that their shape is mostly affected by the slope of the i... 17. Hydride formation thermodynamics and hysteresis in individual Pd nanocrystals with different size and shape. Science.gov (United States) Syrenova, Svetlana; Wadell, Carl; Nugroho, Ferry A A; Gschneidtner, Tina A; Diaz Fernandez, Yuri A; Nalin, Giammarco; Świtlik, Dominika; Westerlund, Fredrik; Antosiewicz, Tomasz J; Zhdanov, Vladimir P; Moth-Poulsen, Kasper; Langhammer, Christoph 2015-12-01 Physicochemical properties of nanoparticles may depend on their size and shape and are traditionally assessed in ensemble-level experiments, which accordingly may be plagued by averaging effects. These effects can be eliminated in single-nanoparticle experiments. Using plasmonic nanospectroscopy, we present a comprehensive study of hydride formation thermodynamics in individual Pd nanocrystals of different size and shape, and find corresponding enthalpies and entropies to be nearly size- and shape-independent. The hysteresis observed is significantly wider than in bulk, with details depending on the specifics of individual nanoparticles. Generally, the absorption branch of the hysteresis loop is size-dependent in the sub-30 nm regime, whereas desorption is size- and shape-independent. The former is consistent with a coherent phase transition during hydride formation, influenced kinetically by the specifics of nucleation, whereas the latter implies that hydride decomposition either occurs incoherently or via different kinetic pathways. 18. Properties of hydrogen permeation barrier on the surface of zirconium hydride Institute of Scientific and Technical Information of China (English) CHEN Weidong; WANG Lijun; HAN Lin; CHEN Song 2008-01-01 A hydrogen permeation barrier was manufactured by the in situ reaction of zirconium hydride with oxygen.A reduction in the hydrogen permeation of the oxide films was detected by measuring the mass difference of the zirconium hydride samples after the dehydrogenation experiment.The reaction of zirconium hydride with oxygen occurs only under the condition that the temperature is higher than 673 K in the oxygen partial pressure of 0.1 MPa.The oxide film is composed of two layers,a permeable oxide layer and a dense oxide layer,and the main phase of the oxide film is ZrO2 with baddeleyite structure.The XPS analysis shows that O-H bonds exist in the oxide film,which are helpful for resisting hydrogen diffusion through the oxide film. 19. Technical Status Report on the Effect of Phosphate and Aluminum on the Development of Amorphous Phase Separation in Sodium Energy Technology Data Exchange (ETDEWEB) Cozzi, A.D. 1998-11-03 The objective of the Tank Focus Area ''Optimize Waste Loading'' task is to enhance the definition of the acceptable processing window for high-level waste vitrification plants. One possible manner in which the acceptable processing window may be enhanced is by reducing the uncertainty of various compositional/property models through a specifically defined experimental plan. A reduction in model uncertainty can reduce limitations on current acceptance constraints and may allow for a larger processing or operational window. Enhanced composition/property model predictions coupled with an increased waste loading may decrease the processing time and waste glass disposal costs (i.e., overall lifecycle costs). One of the compositional/property models currently being evaluated by the Tanks Focus Area is related to the development of amorphous phase separation in multi-component borosilicate glasses.Described in this report is the current status for evaluating the effect of phosphorus and alumina on both simple sodium borosilicate and high-level waste glasses on the formation of amorphous phase separation. The goal of this subtask is to increase the understanding of the formation of phase separation by adding significant amounts (3-5 wt. percent) of phosphorus and alumina to well-characterized glasses. Additional scope includes evaluating the effects of thermal history on the formation of amorphous phase separation and durability of select glasses.The development of data, understanding, and quantitative description for composition and kinetic effects on the development of amorphous phase separation will continue in FY99. This effort will provide insight into the compositional and thermal effects on phase stability and will lead to a better understanding of the methods used to predict the development of amorphous phase separation in HLW glasses. 20. In situ generation of hydrogen from water by aluminum corrosion in solutions of sodium aluminate OpenAIRE Soler Turu, Lluis; Candela Soto, Angélica Maria; Macanás de Benito, Jorge; Muñoz Tapia, Maria; Casado Giménez, Juan 2009-01-01 A new process to obtain hydrogen from water using aluminum in sodium aluminate solutions is described and compared with results obtained in aqueous sodium hydroxide. This process consumes only water and aluminum, which are raw materials much cheaper than other compounds used for in situ hydrogen generation, such as hydrocarbons and chemical hydrides, respectively. As a consequence, our process could be an economically feasible alternative for hydrogen to supply fuel cells. Results showed an i... 1. Discovery of Novel Complex Metal Hydrides for Hydrogen Storage through Molecular Modeling and Combinatorial Methods Energy Technology Data Exchange (ETDEWEB) Lesch, David A; Adriaan Sachtler, J.W. J.; Low, John J; Jensen, Craig M; Ozolins, Vidvuds; Siegel, Don; Harmon, Laurel 2011-02-14 UOP LLC, a Honeywell Company, Ford Motor Company, and Striatus, Inc., collaborated with Professor Craig Jensen of the University of Hawaii and Professor Vidvuds Ozolins of University of California, Los Angeles on a multi-year cost-shared program to discover novel complex metal hydrides for hydrogen storage. This innovative program combined sophisticated molecular modeling with high throughput combinatorial experiments to maximize the probability of identifying commercially relevant, economical hydrogen storage materials with broad application. A set of tools was developed to pursue the medium throughput (MT) and high throughput (HT) combinatorial exploratory investigation of novel complex metal hydrides for hydrogen storage. The assay programs consisted of monitoring hydrogen evolution as a function of temperature. This project also incorporated theoretical methods to help select candidate materials families for testing. The Virtual High Throughput Screening served as a virtual laboratory, calculating structures and their properties. First Principles calculations were applied to various systems to examine hydrogen storage reaction pathways and the associated thermodynamics. The experimental program began with the validation of the MT assay tool with NaAlH4/0.02 mole Ti, the state of the art hydrogen storage system given by decomposition of sodium alanate to sodium hydride, aluminum metal, and hydrogen. Once certified, a combinatorial 21-point study of the NaAlH4 LiAlH4Mg(AlH4)2 phase diagram was investigated with the MT assay. Stability proved to be a problem as many of the materials decomposed during synthesis, altering the expected assay results. This resulted in repeating the entire experiment with a mild milling approach, which only temporarily increased capacity. NaAlH4 was the best performer in both studies and no new mixed alanates were observed, a result consistent with the VHTS. Powder XRD suggested that the reverse reaction, the regeneration of the 2. Discovery of Novel Complex Metal Hydrides for Hydrogen Storage through Molecular Modeling and Combinatorial Methods Energy Technology Data Exchange (ETDEWEB) Lesch, David A; Adriaan Sachtler, J.W. J.; Low, John J; Jensen, Craig M; Ozolins, Vidvuds; Siegel, Don; Harmon, Laurel 2011-02-14 UOP LLC, a Honeywell Company, Ford Motor Company, and Striatus, Inc., collaborated with Professor Craig Jensen of the University of Hawaii and Professor Vidvuds Ozolins of University of California, Los Angeles on a multi-year cost-shared program to discover novel complex metal hydrides for hydrogen storage. This innovative program combined sophisticated molecular modeling with high throughput combinatorial experiments to maximize the probability of identifying commercially relevant, economical hydrogen storage materials with broad application. A set of tools was developed to pursue the medium throughput (MT) and high throughput (HT) combinatorial exploratory investigation of novel complex metal hydrides for hydrogen storage. The assay programs consisted of monitoring hydrogen evolution as a function of temperature. This project also incorporated theoretical methods to help select candidate materials families for testing. The Virtual High Throughput Screening served as a virtual laboratory, calculating structures and their properties. First Principles calculations were applied to various systems to examine hydrogen storage reaction pathways and the associated thermodynamics. The experimental program began with the validation of the MT assay tool with NaAlH4/0.02 mole Ti, the state of the art hydrogen storage system given by decomposition of sodium alanate to sodium hydride, aluminum metal, and hydrogen. Once certified, a combinatorial 21-point study of the NaAlH4 LiAlH4Mg(AlH4)2 phase diagram was investigated with the MT assay. Stability proved to be a problem as many of the materials decomposed during synthesis, altering the expected assay results. This resulted in repeating the entire experiment with a mild milling approach, which only temporarily increased capacity. NaAlH4 was the best performer in both studies and no new mixed alanates were observed, a result consistent with the VHTS. Powder XRD suggested that the reverse reaction, the regeneration of the 3. 物相定量分析在铝工业中的应用%Application of Phase Quantitative Analysis in Aluminum Industry Institute of Scientific and Technical Information of China (English) 李波; 郭永恒 2011-01-01 总结介绍了到目前为止在铝工业中应用的物相定量分析方法,分析了各种方法的应用范围以及优缺点,包括化学物相定量法、外标法、化学物相计算法、X射线衍射增量法、K值法、绝热法、Rietveld全谱拟合定量法、K值法和化学物相计算法结合以及Zevin无标定量法等.结果表明:每种物相定量分析方法都有各自的优点和缺点,需要根据样品的实际情况,选择最适当的分析方法,才能得到准确的结果.%Phase quantitative analysis methods which had been used in aluminum industry by now were summarized and introduced, and application range, merits and demerits of each method were analyzed respectively,including chemical in quantitative method, external standard method, chemical quantitative calculating method,X-ray diffraction incremental method, K value method, adiabatic method, Rietveld full pattern fitting quantitative method, combining K value method and chemical phase calculation method, Zevin no standard quantitative method,and so on. The results show that each method has its advantages and disadvantages. In order to obtain accurate results, it should according to actual situation of the sample to select the most appropriate phase quantitative analysis method. 4. Hydrogen in aluminum during alkaline corrosion Energy Technology Data Exchange (ETDEWEB) Adhikari, Saikat; Ai, Jiahe [Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States); Hebert, Kurt R., E-mail: krhebert@iastate.ed [Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States); Ho, K.M.; Wang, C.Z. [US DOE, Ames Laboratory, Ames, IA 50011 (United States)] [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States) 2010-07-30 The thermodynamic state of hydrogen in aluminum during alkaline corrosion was investigated, using a two-compartment hydrogen permeation cell with an Al/Pd bilayer membrane. The open-circuit potential of the Pd layer in a pH 7.0 buffer solution was monitored to sense the hydrogen chemical potential, {mu}{sub H}. At pH 12.5-13.5, the measurements established a minimum {mu}{sub H} of 0.55 eV relative to the ideal gas reference, equivalent to a H{sub 2} gas pressure of 5.7 GPa. Statistical mechanics calculations show that vacancy-hydrogen defects are stable in Al at this condition. A dissolution mechanism was proposed in which H at very high {mu}{sub H} is produced by oxidation of interfacial aluminum hydride. The mechanism explains the observed rapid accumulation of H in the metal by extensive formation of vacancy-hydrogen defects. 5. Nanoscale studies of the early stages of phase separation in model nickel-aluminum-chromium-X superalloys Science.gov (United States) Booth-Morrison, Christopher The phase separation of model Ni-Al-Cr-X alloys is studied at the nanoscale employing atom-probe tomography (APT), electron microscopy and first-principles calculations. A comparison of the kinetic pathways resulting from the formation of coherent gamma'-precipitates in two Ni-Al-Cr alloys, Ni-7.5 Al-8.5 Cr and Ni-5.2 Al-14.2 Cr at.%, with similar gamma'-precipitate volume fractions at 873 K, is performed. The morphologies of the gamma'-precipitates of the alloys are similar, though the degrees of gamma'-precipitate coagulation and coalescence differ. Quantification within the framework of classical nucleation theory reveals that differences in the chemical driving forces for phase decomposition result in differences in the nucleation behavior of the two alloys. The temporal evolution of the gamma'-precipitate average radii and the gamma-matrix supersaturations follow the predictions of classical coarsening models. The compositional trajectories of the gamma-matrix phases of the alloys are found to follow approximately the equilibrium tie-lines, while the trajectories of the gamma'-precipitates do not, resulting in significant differences in the partitioning ratios of the solute elements. Phase separation in a Ni-6.5 Al-9.5 Cr at.% alloy aged at 873 K occurs in four distinct regimes: (i) quasi-stationary-state gamma' (L12)-precipitate nucleation; (ii) concomitant precipitate nucleation, growth, and coagulation and coalescence; (iii) concurrent growth and coarsening, wherein coarsening occurs via both gamma'-precipitate coagulation and coalescence and by the classical evaporation-condensation mechanism; and (iv) quasi-stationary-state coarsening of gamma'-precipitates, once the equilibrium volume fraction of precipitates is achieved. The predictions of classical nucleation and growth models are not validated experimentally, likely due to the complexity of the atomistic kinetic pathways involved in precipitation. During coarsening, the temporal evolution of the gamma 6. Mathematical modeling of the nickel/metal hydride battery system Energy Technology Data Exchange (ETDEWEB) Paxton, B K [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering 1995-09-01 A group of compounds referred to as metal hydrides, when used as electrode materials, is a less toxic alternative to the cadmium hydroxide electrode found in nickel/cadmium secondary battery systems. For this and other reasons, the nickel/metal hydride battery system is becoming a popular rechargeable battery for electric vehicle and consumer electronics applications. A model of this battery system is presented. Specifically the metal hydride material, LaNi{sub 5}H{sub 6}, is chosen for investigation due to the wealth of information available in the literature on this compound. The model results are compared to experiments found in the literature. Fundamental analyses as well as engineering optimizations are performed from the results of the battery model. In order to examine diffusion limitations in the nickel oxide electrode, a pseudo 2-D model is developed. This model allows for the theoretical examination of the effects of a diffusion coefficient that is a function of the state of charge of the active material. It is found using present data from the literature that diffusion in the solid phase is usually not an important limitation in the nickel oxide electrode. This finding is contrary to the conclusions reached by other authors. Although diffusion in the nickel oxide active material is treated rigorously with the pseudo 2-D model, a general methodology is presented for determining the best constant diffusion coefficient to use in a standard one-dimensional battery model. The diffusion coefficients determined by this method are shown to be able to partially capture the behavior that results from a diffusion coefficient that varies with the state of charge of the active material. 7. Porous carbon derived from aluminum-based metal organic framework as a fiber coating for the solid-phase microextraction of polycyclic aromatic hydrocarbons from water and soil International Nuclear Information System (INIS) A nanoporous carbon derived from an aluminum-based metal-organic framework was deposited on stainless steel wires in a sol–gel matrix. The resulting fibers were applied to the solid-phase microextraction of the polycyclic aromatic hydrocarbons (PAHs) naphthalene, acenaphthene, fluorene, phenanthrene and anthracene from water and soil samples. The fiber was then directly inserted into the GC injector and the PAHs were quantified by GC-MS. The effects of salt addition, extraction temperature, extraction time, sample volume and desorption conditions on the extraction efficiency were optimized. A linear response to the analytes was observed in the 0.1 to 12 μg∙L−1 range for water samples, and in the 0.6 to 30 μg∙kg−1 for soil samples, with the correlation coefficients ranging from 0.9934 to 0.9985. The limits of detection ranged from 5.0 to 20 ng∙L−1 for water samples, and from 30 to 90 ng∙kg−1 for soil samples. The recoveries of spiked samples were between 72.4 and 108.0 %, and the precision, expressed as the relative standard deviations, is <12.8 %. (author) 8. Study of mechanical joint strength of aluminum alloy 7075-T6 and dual phase steel 980 welded by friction bit joining and weld-bonding under corrosion medium International Nuclear Information System (INIS) Highlights: • Friction bit joining (FBJ) and weld-bonding (adhesive + FBJ) processes. • FBJ to spot weld high-strength Al alloy to high-strength steel. • Lap shear strength of ∼10 kN for high-strength Al alloy to high-strength steel. • Effective corrosion mitigation by combining FBJ with adhesive. - Abstract: In this work, we have employed a unique solid-sate joining process, called friction bit joining (FBJ), to spot weld aluminum alloy (AA) 7075-T6 and dual phase (DP) 980 steel. Static joint strength was studied in the lap shear tension configuration. In addition, weld-bonding (adhesive + FBJ) joints were studied in order to evaluate the ability of adhesive to mitigate the impact of corrosion on joint properties. Accelerated laboratory cyclic corrosion tests were carried out for both FBJ only and weld-bonding joints. The FBJ only joints that emerged from corrosion testing had lap shear failure loads that were significantly lower than freshly prepared joints. However, weld-bonding specimens retained more than 80% of the lap shear failure load of the freshly prepared weld-bonding specimens. Examination of joint cross sections confirmed that the presence of adhesive in the weld-bonding joints mitigated the effect of the corrosion environment, compared to FBJ only joints 9. Vapor-phase polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) on commercial carbon coated aluminum foil as enhanced electrodes for supercapacitors Science.gov (United States) Tong, Linyue; Skorenko, Kenneth H.; Faucett, Austin C.; Boyer, Steven M.; Liu, Jian; Mativetsky, Jeffrey M.; Bernier, William E.; Jones, Wayne E. 2015-11-01 Laminar composite electrodes are prepared for application in supercapacitors using a catalyzed vapor-phase polymerization (VPP) of 3,4-ethylenedioxythiophene (EDOT) on the surface of commercial carbon coated aluminum foil. These highly electrically conducting polymer films provide for rapid and stable power storage per gram at room temperature. The chemical composition, surface morphology and electrical properties are characterized by Raman spectroscopy, scanning electron microscopy (SEM), and conducting atomic force microscopy (C-AFM). A series of electrical measurements including cyclic voltammetry (CV), charge-discharge (CD) and electrochemical impedance spectroscopy are also used to evaluate electrical performance. The processing temperature of VPP shows a significant effect on PEDOT morphology, the degree of orientation and its electrical properties. The relatively high temperature leads to high specific area and large conductive domains of PEDOT layer which benefits the capacitive behavior greatly according to the data presented. Since the substrate is already highly conductive, the PEDOT based composite can be used as electrode materials directly without adding current collector. By this simple and efficient process, PEDOT based composites exhibit specific capacitance up to 134 F g-1 with the polymerization temperature of 110 °C. 10. Draft of M2 Report on Integration of the Hybrid Hydride Model into INL's MBM Framework for Review Energy Technology Data Exchange (ETDEWEB) Tikare, Veena; Weck, Philippe F.; Schultz, Peter Andrew; Clark, Blythe; Glazoff, Michael V.; Homer, Eric R. 2014-07-01 This report documents the development, demonstration and validation of a mesoscale, microstructural evolution model for simulation of zirconium hydride {delta}-ZrH{sub 1.5} precipitation in the cladding of used nuclear fuels that may occur during long-term dry storage. While the Zr-based claddings are manufactured free of any hydrogen, they absorb hydrogen during service, in the reactor by a process commonly termed ‘hydrogen pick-up’. The precipitation and growth of zirconium hydrides during dry storage is one of the most likely fuel rod integrity failure mechanisms either by embrittlement or delayed hydride cracking of the cladding. While the phenomenon is well documented and identified as a potential key failure mechanism during long-term dry storage (NUREG/CR-7116), the ability to actually predict the formation of hydrides is poor. The model being documented in this work is a computational capability for the prediction of hydride formation in different claddings of used nuclear fuels. This work supports the Used Fuel Disposition Research and Development Campaign in assessing the structural engineering performance of the cladding during and after long-term dry storage. This document demonstrates a basic hydride precipitation model that is built on a recently developed hybrid Potts-phase field model that combines elements of Potts-Monte Carlo and the phase-field models. The model capabilities are demonstrated along with the incorporation of the starting microstructure, thermodynamics of the Zr-H system and the hydride formation mechanism. 11. The Mg{sub 2}Si phase evolution during thermomechanical processing of in-situ aluminum matrix macro-composite Energy Technology Data Exchange (ETDEWEB) Shafieizad, A.H. [The Complex Laboratory of Hot Deformation & Thermomechanical Processing of High Performance Engineering Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Zarei-Hanzaki, A., E-mail: Zareih@ut.ac.ir [The Complex Laboratory of Hot Deformation & Thermomechanical Processing of High Performance Engineering Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Abedi, H.R. [The Complex Laboratory of Hot Deformation & Thermomechanical Processing of High Performance Engineering Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Al-Fadhalah, K.J. [Department of Mechanical Engineering, College of Engineering & Petroleum, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait) 2015-09-17 The microstructure and flow stress behavior of thermomechanically processed Al–Cu/Mg{sub 2}Si in-situ composite was studied emphasizing the evolution of primary and secondary reinforcement phases. Toward this end, the hot compression tests were conducted over the wide range of temperature (300–500 °C) and strain rate (0.001–0.1 s{sup −1}). Both the temperature and strain rate are found to possess a significant effect on the microstructural characteristics where a considerable softening is identified specially at low temperature regime. Besides the occurrence of restoration processes (mainly particle stimulated nucleation) the dynamic evolution of the reinforcements is introduced as the main factors affecting the reported softening. In this regard, the mechanical fragmentation, thermal disintegration, micro-buckling, coalescence and spheroidization of the primary and secondary particles are quantitatively and qualitatively addressed through a comprehensive scanning electron microscopy studies. 12. Pressure-induced transformations of molecular boron hydride CERN Document Server Nakano, S; Gregoryanz, E A; Goncharov, A F; Mao Ho Kwang 2002-01-01 Decaborane, a molecular boron hydride, was compressed to 131 GPa at room temperature to explore possible non-molecular phases in this system and their physical properties. Decaborane changed its colour from transparent yellow to orange/red above 50 GPa and then to black above 100 GPa, suggesting some transformations. Raman scattering and infrared (IR) absorption spectroscopy reveal significant structural changes. Above 100 GPa, B-B skeletal, B-H and B-H-B Raman/IR peaks gradually disappeared, which implies a transformation into a non-molecular phase in which conventional borane-type bonding is lost. The optical band gap of the material at 100 GPa was estimated to be about 1.0 eV. 13. A Study on the Radial Hydride Assisted Delayed Hydride Cracking of Zircaloy Energy Technology Data Exchange (ETDEWEB) Jeong, Jin-Ho; Lee, Ji-Min; Kim, Yong-Soo [Hanyang University, Seoul (Korea, Republic of) 2015-05-15 Extensive studies have been done on understanding of DHC(Delayed hydride cracking) phenomenon since several zirconium alloy pressure tubes failed in nuclear reactor in the 1970s. Recently, long-term dry storage strategy has been considered seriously in order to manage spent nuclear fuel in Korea and other countries around the world. Consequentially, many researches have been investigated the degradation mechanisms which will threaten the spent fuel integrity during dry storage and showed that hydrogen related phenomenon such as hydride reorientation and DHC are the critical factors. Especially, DHC is the direct cracking mechanism which can cause not only a through-wall defect but also a radiation leak to the environment. In addition, DHC can be enhanced by radial hydride as reported by Kim who demonstrate that radial hydrides clearly act as crack linkage path. This phenomenon is known as the radial hydride assisted DHC (RHA-DHC). Therefore, study on DHC is essential to ensure the safety of spent fuel. Finite element analysis will be carried out for the stress gradient evaluation around notch tip. A variation in thermal cycle which leads to change in hydrogen solid solution trajectory may be required. If the radial hydride precipitates at notch tip, we will investigate what conditions should be met. Ultimately, we will suggest the regulation criteria for long-term dry storage of spent nuclear fuel. 14. Computational study of metal hydride cooling system Energy Technology Data Exchange (ETDEWEB) Satheesh, A.; Muthukumar, P.; Dewan, Anupam [Department of Mechanical Engineering, Indian Institute of Technology, Guwahati, Guwahati 781039 (India) 2009-04-15 A computational study of a metal hydride cooling system working with MmNi{sub 4.6}Al{sub 0.4}/MmNi{sub 4.6}Fe{sub 0.4} hydride pair is presented. The unsteady, two-dimensional mathematical model in an annular cylindrical configuration is solved numerically for predicting the time dependent conjugate heat and mass transfer characteristics between coupled reactors. The system of equations is solved by the fully implicit finite volume method (FVM). The effects of constant and variable wall temperature boundary conditions on the reaction bed temperature distribution, hydrogen concentration, and equilibrium pressures of the reactors are investigated. A dynamic correlation of the pressure-concentration-temperature plot is presented. At the given operating temperatures of 363/298/278 K (T{sub H}/T{sub M}/T{sub C}), the cycle time for the constant and variable wall temperature boundary conditions of a single-stage and single-effect metal hydride system are found to be 1470.0 s and 1765.6 s, respectively. The computational results are compared with the experimental data reported in the literature for LaNi{sub 4.61}Mn{sub 0.26}Al{sub 0.13}/La{sub 0.6}Y{sub 0.4}Ni{sub 4.8}Mn{sub 0.2} hydride pair and a good agreement between the two was observed. (author) 15. The electrochemical impedance of metal hydride electrodes DEFF Research Database (Denmark) Valøen, Lars Ole; Lasia, Andrzej; Jensen, Jens Oluf; 2002-01-01 The electrochemical impedance responses for different laboratory type metal hydride electrodes were successfully modeled and fitted to experimental data for AB5 type hydrogen storage alloys as well as one MgNi type electrode. The models fitted the experimental data remarkably well. Several AC equ... 16. Separation of covalent hydrides by gas-solid chromatography International Nuclear Information System (INIS) A fully automated method was developed for separating the hydrides of elements of the IVth to VIIIth main subgroup of the periodic system and of Kr and Xe on the basis of their volatility using gas chromatography. The automated instrument allowing to carry out reduction, separation of the gaseous phase, the loading of a PORAPAK-packed column, the chromatographic separation and sampling was controlled by a HP 2116B computer. The elution time, peak area and the number of theoretical column plates were computed from chromatograms. The capture probably proceeded by a type of nonpolar nonspecific sorption (ΔH/Tsub(b) = 19.2 cal/mol.deg). The height of the theoretical plate was 0.05 to 0.1 cm. The technique may be used as a routine radiochemical method for group separations and for the separation of radioactive hydrides contained in the solution of targets irradiated with neutrons or charged particles in the preparation of radioactive sources of short-lived radionuclides, or in destructive activation analysis. (M.K.) 17. Electronic structure of the palladium hydride studied by compton scattering CERN Document Server Mizusaki, S; Yamaguchi, M; Hiraoka, N; Itou, M; Sakurai, Y 2003-01-01 The hydrogen-induced changes in the electronic structure of Pd have been investigated by Compton scattering experiments associated with theoretical calculations. Compton profiles (CPs) of single crystal of Pd and beta phase hydride PdH sub x (x=0.62-0.74) have been measured along the [100], [110] and [111] directions with a momentum resolution of 0.14-0.17 atomic units using 115 keV x-rays. The theoretical Compton profiles have been calculated from the wavefunctions obtained utilizing the full potential linearized augmented plane wave method within the local density approximation for Pd and stoichiometric PdH. The experimental and the theoretical results agreed well with respect to the difference in the CPs between PdH sub x and Pd, and the anisotropy in the CPs of Pd or PdH sub x. This study provides lines of evidence that upon hydride formation the lowest valance band of Pd is largely modified due to hybridization with H 1s-orbitals and the Fermi energy is raised into the sp-band. (author) 18. Hydride Formation in Neutron Irradiated Material Under In Reactor Conditions International Nuclear Information System (INIS) The present is a brief summary of the three reports completed within the framework of the SPAR III project. The following is a resume of our aims, techniques used to achieve the objectives and conclusions attained under the guiding thread of the hydride formation in neutron irradiated zirconium alloys and other reactor in operating conditions. As is it known, under reactor operating conditions zirconium components go through transformations which affect their original microstructural and thermodynamical properties. Both concerns are starting points of many research lines for the zirconium alloys used in the nuclear power reactors. Regarding microstructural transformations, one of the most important topics is the phase stability of these alloys. To cite a well-known case, second phase particles of zircaloy-4 shown to be unstable under neutron radiation. Since such phases play a role in the corrosion rate control, this instability became a problem for high burnup fuel claddings design. Similar observations can be made about the β−Zr phase in the Zr-2.5Nb CANDU pressure tubes alloy. On the other hand, there are issues directly involved with thermodynamics, e.g., hydrogen behaviour and its role in the degradation processes of fuel assemblies and other zirconium alloys components, which showed to be affected by neutron radiation. Finally, applied stresses and thermal cycling are part of these operating conditions, which can be simulated performing experiments in situ which allows testing hydrogen solubility behaviour and hydride reorientation. In the context described above, the research topics proposed to SPAR III were aimed to improve the knowledge of these degradation processes. In this scheme, zircaloy-4 which remained more than ten years at full power operation and virgin unirradiated zirconium alloys were suited by the more improved micro analytical techniques to characterize microstructural transformations cited above 19. CATALYST ACTIVITY MAINTENANCE FOR THE LIQUID PHASE SYNTHESIS GAS-TO-DIMETHYL ETHER PROCESS PART II: DEVELOPMENT OF ALUMINUM PHOSPHATE AS THE DEHYDRATION CATALYST FOR THE SINGLE-STEP LIQUID PHASE SYNGAS-TO-DME PROCESS Energy Technology Data Exchange (ETDEWEB) Xiang-Dong Peng 2002-05-01 At the heart of the single-step liquid phase syngas-to-DME process (LPDME{trademark}) is a catalyst system that can be active as well as stable. In the Alternative Fuels I program, a dual-catalyst system containing a Cu-based commercial methanol synthesis catalyst (BASF S3-86) and a commercial dehydration material ({gamma}-alumina) was demonstrated. It provided the productivity and selectivity expected from the LPDME process. However, the catalyst system deactivated too rapidly to warrant a viable commercial process [1]. The mechanistic investigation in the early part of the DOE's Alternative Fuels II program revealed that the accelerated catalyst deactivation under LPDME conditions is due to detrimental interaction between the methanol synthesis catalyst and methanol dehydration catalyst [2,3]. The interaction was attributed to migration of Cu- and/or Zn-containing species from the synthesis catalyst to the dehydration catalyst. Identification of a dehydration catalyst that did not lead to this detrimental interaction while retaining adequate dehydration activity was elusive. Twenty-nine different dehydration materials were tested, but none showed the desired performance [2]. The search came to a turning point when aluminum phosphate was tested. This amorphous material is prepared by precipitating a solution containing Al(NO{sub 3}){sub 3} and H{sub 3}PO{sub 4} with NH{sub 4}OH, followed by washing, drying and calcination. The aluminum phosphate catalyst has adequate dehydration activity and good stability. It can co-exist with the Cu-based methanol synthesis catalyst without negatively affecting the latter catalyst's stability. This report documents the details of the development of this catalyst. These include initial leads, efforts in improving activity and stability, investigation and development of the best preparation parameters and procedures, mechanistic understanding and resulting preparation guidelines, and the accomplishments of this work. 20. Performances of Aluminum-cobalt Co-substituted α-Ni(OH)2 Electrodes Institute of Scientific and Technical Information of China (English) ZHANG Heng-bin; LIU Han-san; CAO Xue-jing; SUN Chia-chung 2004-01-01 Aluminum-cobalt co-substituted α-Ni(OH)2 was prepared by means of the titration method in a buffer solution, the structure was characterized by XRD analysis. With above mentioned α-Ni(OH)2 as the positive electrode of a nickel-metal hydride cell, the discharge performances were examined by constant-current charge-discharge experiments. In comparison with the electrodes made of aluminum substituted or cobalt substituted Ni(OH)2 materials, the aluminum-cobalt co-substituted composite electrodes possess an excellent electrochemical performance and are of practical significance. 1. Structural and hydrogen storage capacity evolution of Mg2FeH6 hydride synthesized by reactive mechanical alloying Institute of Scientific and Technical Information of China (English) LI Song-lin(李松林); R.A.Varin 2004-01-01 Mg-based metal hydrides are promising as hydrogen storage materials for fuel cell application. In this work, Mg2 FeH6 complex hydride phase was synthesized by controlled reactive ball milling of 2Mg-Fe (atomic ratio)powder mixture in H2. Mg2 FeH6 is confirmed to be formed via the following three stages: formation of MgH2 via the reaction of Mg with H2, incubation stage and formation of Mg2 FeH6 by reaction of fully refined MgH2 and Fe.The incubation stage is characterized by no traces of Mg or hydride crystalline phase by XRD. On the other hand,Mg is observed uniformly distributed in the milled powder by SEM-EDS. Also, almost the same amount of H2 as the first stage is detected stored in the powders of the second stage by DSC and TGA. 2. Coupled phase field, heat conduction, and elastodynamic simulations of kinetic superheating and nanoscale melting of aluminum nanolayer irradiated by picosecond laser. Science.gov (United States) Hwang, Yong Seok; Levitas, Valery I 2015-12-21 An advanced continuum model for nanoscale melting and kinetic superheating of an aluminum nanolayer irradiated by a picosecond laser is formulated. Barrierless nucleation of surface premelting and melting occurs, followed by a propagation of two solid-melt interfaces toward each other and their collision. For a slow heating rate of Q = 0.015 K ps(-1) melting occurs at the equilibrium melting temperature under uniaxial strain conditions T = 898.1 K (i.e., below equilibrium melting temperature Teq = 933.67 K) and corresponding biaxial stresses, which relax during melting. For a high heating rate of Q = 0.99-84 K ps(-1), melting occurs significantly above Teq. Surprisingly, an increase in heating rate leads to temperature reduction at the 3 nm wide moving interfaces due to fast absorption of the heat of fusion. A significant, rapid temperature drop (100-500 K, even below melting temperature) at the very end of melting is revealed, which is caused by the collision of two finite-width interfaces and accelerated melting in about the 5 nm zone. For Q = 25-84 K ps(-1), standing elastic stress waves are observed in a solid with nodal points at the moving solid-melt interfaces, which, however, do not have a profound effect on melting time or temperatures. When surface melting is suppressed, barrierless bulk melting occurs in the entire sample, and elastodynamic effects are more important. Good correspondence with published, experimentally-determined melting time is found for a broad range of heating rates. Similar approaches can be applied to study various phase transformations in different materials and nanostructures under high heating rates. 3. Evaluated the adverse effects of cadmium and aluminum via drinking water to kidney disease patients: Application of a novel solid phase microextraction method. Science.gov (United States) Panhwar, Abdul Haleem; Kazi, Tasneem Gul; Naeemullah; Afridi, Hassan Imran; Shah, Faheem; Arain, Mohammad Balal; Arain, Salma Aslam 2016-04-01 In present study aluminum (Al) and cadmium (Cd) were determined in ground water samples and assesses human health risks associated with elevated concentrations of toxic metals in dissolved form, using a novel solid phase microextraction (SPμE). Ground water sample (n=200) and biological sample (blood) of patients having chronic kidney disorders (CKD) along with healthy control subjects of same area (southern part of Pakistan) were collected. A simple system, including the micropipette tip packed with modified ionic liquid-activated carbon cloth (IL-ACC) coated with 8-hydroxyqunilone (8-HQ) attached to syringe. The analytes in water and acid digested blood samples were manually drawn for 2-10 cycles (drawing/discharging) at different pH range. The analytes sorbed on coated ACC were then desorbed with 2.0molL(-1) HNO3 in ethanol by drawing/discharging cycles for 1-5 times. The concentration of extracted analytes was determined by electrothermal atomic absorption spectrometer. The influence of different variables on the extraction efficiency of Cd and Al, were optimized. The Al and Cd concentrations in groundwater were found to be elevated than recommended limits by the World Health Organization. The urinary N-acetyl-h-glucosaminidase values were significantly higher in CKD patients as compared to refrent subjects (p<0.001). The significant variation in levels of Cd and Al were observed in blood samples of CKD patients than referents subjects (p<0.01). The strong positive correlation among Al and Cd levels in groundwater versus blood samples of CKD patients (r=0.82-0.85) p<0.01) was observed than those values calculated for referent subjects (r=0.425-0.536). PMID:27037653 4. Evaluated the adverse effects of cadmium and aluminum via drinking water to kidney disease patients: Application of a novel solid phase microextraction method. Science.gov (United States) Panhwar, Abdul Haleem; Kazi, Tasneem Gul; Naeemullah; Afridi, Hassan Imran; Shah, Faheem; Arain, Mohammad Balal; Arain, Salma Aslam 2016-04-01 In present study aluminum (Al) and cadmium (Cd) were determined in ground water samples and assesses human health risks associated with elevated concentrations of toxic metals in dissolved form, using a novel solid phase microextraction (SPμE). Ground water sample (n=200) and biological sample (blood) of patients having chronic kidney disorders (CKD) along with healthy control subjects of same area (southern part of Pakistan) were collected. A simple system, including the micropipette tip packed with modified ionic liquid-activated carbon cloth (IL-ACC) coated with 8-hydroxyqunilone (8-HQ) attached to syringe. The analytes in water and acid digested blood samples were manually drawn for 2-10 cycles (drawing/discharging) at different pH range. The analytes sorbed on coated ACC were then desorbed with 2.0molL(-1) HNO3 in ethanol by drawing/discharging cycles for 1-5 times. The concentration of extracted analytes was determined by electrothermal atomic absorption spectrometer. The influence of different variables on the extraction efficiency of Cd and Al, were optimized. The Al and Cd concentrations in groundwater were found to be elevated than recommended limits by the World Health Organization. The urinary N-acetyl-h-glucosaminidase values were significantly higher in CKD patients as compared to refrent subjects (p<0.001). The significant variation in levels of Cd and Al were observed in blood samples of CKD patients than referents subjects (p<0.01). The strong positive correlation among Al and Cd levels in groundwater versus blood samples of CKD patients (r=0.82-0.85) p<0.01) was observed than those values calculated for referent subjects (r=0.425-0.536). 5. Aluminum-stabilized NB3SN superconductor Science.gov (United States) Scanlan, Ronald M. 1988-01-01 An aluminum-stabilized Nb.sub.3 Sn superconductor and process for producing same, utilizing ultrapure aluminum. Ductile components are co-drawn with aluminum to produce a conductor suitable for winding magnets. After winding, the conductor is heated to convert it to the brittle Nb.sub.3 Sn superconductor phase, using a temperature high enough to perform the transformation but still below the melting point of the aluminum. This results in reaction of substantially all of the niobium, while providing stabilization and react-in-place features which are beneficial in the fabrication of magnets utilizing superconducting materials. 6. Catalyzed light hydride nanomaterials embedded in a micro-channels hydrogen storage container. Science.gov (United States) Dehouche, Zahir; Peretti, Hernán A; Yoo, Yeong; Belkacemi, Khaled; Goyette, Jacques 2009-01-01 Activated alloys synthesized by arc-melting were examined as catalysts for improving the hydrogen sorption characteristics of nanostructured magnesium hydride, proposed as a reversible hydrogen storage material. The MgH(2)-catalyst absorbing materials were prepared by ball milling of pure MgH(2) with hydrided Zr(47)Ni(53), Zr(9)Ni(11), and other alloys investigated. The nanostructured MgH(2)-intermetallic systems were tested at 250 degrees C and catalyst addition of eutectoid Zr(47)Ni(53) resulted in the fastest desorption time and highest initial desorption rate. The catalyzed Mg-hydride with activated Zr(9)Ni(11) and Zr(7)Ni(10) phases showed fast desorption kinetics. Moreover, the results demonstrated that the composition of dispersed Zr(x)Ni(y)catalysts has a strong influence on the amount of accumulated hydrogen and desorption rate of Mg-nanocomposite. Part two covers advanced micro-channels hydrogen storage module design based on the results of semi-empirical computer simulations of heat and mass transfers in the container. The micro-channels reservoir concept offers many advantages over the conventional metal hydride hydrogen storage system. It is a micro-structured system that can pack a lot of power into a small space and dissipate effectively the heat of the sorption reactions. This review summarizes recent patents related to CNTS. 7. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides Energy Technology Data Exchange (ETDEWEB) Börries, S., E-mail: stefan.boerries@hzg.de [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany); Metz, O.; Pranzas, P.K. [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany); Bücherl, T. [ZTWB Radiochemie München (RCM), Technische Universität München (TUM), Walther-Meissner-Str. 3, D-85748 Garching (Germany); Söllradl, S. [Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRMII), Technische Universität München (TUM), Lichtenbergstr. 1, D-85748 Garching (Germany); Dornheim, M.; Klassen, T.; Schreyer, A. [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany) 2015-10-11 In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail. 8. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides International Nuclear Information System (INIS) In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail 9. Scattering influences in quantitative fission neutron radiography for the in situ analysis of hydrogen distribution in metal hydrides Science.gov (United States) Börries, S.; Metz, O.; Pranzas, P. K.; Bücherl, T.; Söllradl, S.; Dornheim, M.; Klassen, T.; Schreyer, A. 2015-10-01 In situ neutron radiography allows for the time-resolved study of hydrogen distribution in metal hydrides. However, for a precise quantitative investigation of a time-dependent hydrogen content within a host material, an exact knowledge of the corresponding attenuation coefficient is necessary. Additionally, the effect of scattering has to be considered as it is known to violate Beer's law, which is used to determine the amount of hydrogen from a measured intensity distribution. Within this study, we used a metal hydride inside two different hydrogen storage tanks as host systems, consisting of steel and aluminum. The neutron beam attenuation by hydrogen was investigated in these two different setups during the hydrogen absorption process. A linear correlation to the amount of absorbed hydrogen was found, allowing for a readily quantitative investigation. Further, an analysis of scattering contributions on the measured intensity distributions was performed and is described in detail. 10. Aluminum based metal-organic framework-polymer monolith in solid-phase microextraction of penicillins in river water and milk samples. Science.gov (United States) Lirio, Stephen; Liu, Wan-Ling; Lin, Chen-Lan; Lin, Chia-Her; Huang, Hsi-Ya 2016-01-01 In this study, aluminum based metal-organic framework (Al-MOF)-organic polymer monoliths were prepared via microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA) with different weight percentages of Al-MOF (MIL-53; 37.5-62.5%) and subsequently utilized as sorbent in solid-phase microextraction (SPME) of penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin). The Al-MOF-polymer was characterized using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM-energy-dispersive X-ray spectroscopy (SEM-EDS) to clarify the retained crystalline structure well as the homogeneous dispersion of Al-MOF (MIL-53) in polymer monolith. The developed Al-MOF-polymer (MIL-53) monolithic column was evaluated according to its extraction recovery of penicillins. Several parameters affecting the extraction recoveries of penicillins using fabricated Al-MOF-polymer (MIL-53) monolithic column including different MIL-53 weight percentages, column length, pH, desorption solvent, and mobile phase flow rate were investigated. For comparison, different Al-based MOFs (MIL-68, CYCU-4 and DUT-5) were fabricated using the optimized condition for MIL-53-polymer (sample matrix at pH 3, 200μL desorption volume using methanol, 37.5% of MOF, 4-cm column length at 0.100mLmin(-1) flow rate). Among all the Al-MOF-polymers, MIL-53(Al)-polymer still afforded the best extraction recovery for penicillins ranging from 90.5 to 95.7% for intra-day with less than 3.5% relative standard deviations (RSDs) and inter-day precision were in the range of 90.7-97.6% with less than 4.2% RSDs. Meanwhile, the recoveries for column-to-column were in the range of 89.5-93.5% (<3.4% RSDs) while 88.5-90.5% (<5.8% RSDs) for batch-to-batch (n=3). Under the optimal conditions, the limit of detections were in the range of 0.06-0.26μgL(-1) and limit of quantifications between 0.20 and 0.87 11. Aluminum based metal-organic framework-polymer monolith in solid-phase microextraction of penicillins in river water and milk samples. Science.gov (United States) Lirio, Stephen; Liu, Wan-Ling; Lin, Chen-Lan; Lin, Chia-Her; Huang, Hsi-Ya 2016-01-01 In this study, aluminum based metal-organic framework (Al-MOF)-organic polymer monoliths were prepared via microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA) with different weight percentages of Al-MOF (MIL-53; 37.5-62.5%) and subsequently utilized as sorbent in solid-phase microextraction (SPME) of penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin). The Al-MOF-polymer was characterized using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM-energy-dispersive X-ray spectroscopy (SEM-EDS) to clarify the retained crystalline structure well as the homogeneous dispersion of Al-MOF (MIL-53) in polymer monolith. The developed Al-MOF-polymer (MIL-53) monolithic column was evaluated according to its extraction recovery of penicillins. Several parameters affecting the extraction recoveries of penicillins using fabricated Al-MOF-polymer (MIL-53) monolithic column including different MIL-53 weight percentages, column length, pH, desorption solvent, and mobile phase flow rate were investigated. For comparison, different Al-based MOFs (MIL-68, CYCU-4 and DUT-5) were fabricated using the optimized condition for MIL-53-polymer (sample matrix at pH 3, 200μL desorption volume using methanol, 37.5% of MOF, 4-cm column length at 0.100mLmin(-1) flow rate). Among all the Al-MOF-polymers, MIL-53(Al)-polymer still afforded the best extraction recovery for penicillins ranging from 90.5 to 95.7% for intra-day with less than 3.5% relative standard deviations (RSDs) and inter-day precision were in the range of 90.7-97.6% with less than 4.2% RSDs. Meanwhile, the recoveries for column-to-column were in the range of 89.5-93.5% (polymer was applied for the extraction of penicillin in river water and milk by spiking trace-level penicillin for as low as 50μgL(-1) and 100μgL(-1) with recoveries ranging from 80.8% to 90.9% (<6.7% RSDs) in 12. Hydrogen storage in metallic hydrides: the hydrides of magnesium-nickel alloys International Nuclear Information System (INIS) The massive and common use of hydrogen as an energy carrier requires an adequate solution to the problem of storing it. High pressure or low temperatures are not entirely satisfactory, having each a limited range of applications. Reversible metal hydrides cover a range of applications intermediate to high pressure gas and low temperature liquid hydrogen, retaining very favorable safety and energy density characteristics, both for mobile and stationary applications. This work demonstrates the technical viability of storing hydrogen in metal hydrides of magnesium-nickel alloys. Also, it shows that technology, a product of science, can be generated within an academic environment, of the goal is clear, the demand outstanding and the means available. We review briefly theoretical models relating to metal hydride properties, specially the thermodynamics properties relevant to this work. We report our experimental results on hydrides of magnesium-nickel alloys of various compositions including data on structure, hydrogen storage capacities, reaction kinetics, pressure-composition isotherms. We selected a promising alloy for mass production, built and tested a modular storage tank based on the hydrides of the alloy, with a capacity for storing 10 Nm sup(3) of hydrogen of 1 atm and 20 sup(0)C. The tank weighs 46,3 Kg and has a volume of 21 l. (author) 13. Niche applications of metal hydrides and related thermal management issues Energy Technology Data Exchange (ETDEWEB) Lototskyy, M., E-mail: mlototskyy@uwc.ac.za [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Satya Sekhar, B. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Muthukumar, P. [Mechanical Department, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Linkov, V.; Pollet, B.G. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa) 2015-10-05 Highlights: • MH H{sub 2} storage, compression & heat management: developments/thermal management. • Thermodynamic criteria for proper selection of MH for different gas phase applications. • Factors influencing on H{sub 2} charge/discharge dynamic performance and energy efficiency. • The improvement of MH heat transfer characteristics is crucial. • Ways of improvement of heat transfer in the MH systems. - Abstract: This short review highlights and discusses the recent developments and thermal management issues related to metal hydride (MH) systems for hydrogen storage, hydrogen compression and heat management (refrigeration, pump and upgrade, etc.). Special attention is paid to aligning the system features with the requirements of the specific application. The considered system features include the MH material, the MH bed on the basis of its corresponding MH container, as well as the layout of the integrated system. 14. Niche applications of metal hydrides and related thermal management issues International Nuclear Information System (INIS) Highlights: • MH H2 storage, compression & heat management: developments/thermal management. • Thermodynamic criteria for proper selection of MH for different gas phase applications. • Factors influencing on H2 charge/discharge dynamic performance and energy efficiency. • The improvement of MH heat transfer characteristics is crucial. • Ways of improvement of heat transfer in the MH systems. - Abstract: This short review highlights and discusses the recent developments and thermal management issues related to metal hydride (MH) systems for hydrogen storage, hydrogen compression and heat management (refrigeration, pump and upgrade, etc.). Special attention is paid to aligning the system features with the requirements of the specific application. The considered system features include the MH material, the MH bed on the basis of its corresponding MH container, as well as the layout of the integrated system 15. Thermal and mechanical properties of hydrides of Zr–Hf alloys International Nuclear Information System (INIS) Polycrystalline bulk samples of δ-phase Hf hydrides with various Zr contents were prepared and their high-temperature stability and thermal and mechanical properties were investigated. The phase structure was examined between room temperature and 973 K using high-temperature X-ray diffraction and thermogravimetric–differential thermal analysis. From room temperature to 673 K, the coefficient of linear thermal expansion, specific heat capacity, and thermal conductivity were evaluated. The Vickers hardness and sound velocity were measured at room temperature, and the elastic modulus was evaluated. The effect of the Zr content on the high-temperature stability and the thermal and mechanical properties of Hf hydrides was studied. (author) 16. SANS Measurement of Hydrides in Uranium International Nuclear Information System (INIS) SANS scattering is shown to be an effective method for detecting the presence of hydrogen precipitates in uranium. High purity polycrystalline samples of depleted uranium were given several hydriding treatments which included extended exposures to hydrogen gas at two different pressures at 630 C as well as a furnace anneal at 850 C followed by slow cooling in the near absence hydrogen gas. All samples exhibited neutron scattering that was in proportion to the expected levels of hydrogen content. While the scattering signal was strong, the shape of the scattering curve indicated that the scattering objects were large sized objects. Only by use of a very high angular resolution SANS technique was it possible to make estimates of the major diameter of the scattering objects. This analysis permits an estimate of the volume fraction and means size of the hydride precipitates in uranium 17. Metal hydrides based high energy density thermal battery International Nuclear Information System (INIS) Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH2 and TiMnV as a working pair. • High energy density can be achieved by the use of MgH2 to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH2 as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV0.62Mn1.5 alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles 18. Preparation and Properties of Zirconium Hydride on the Surface of MCM-41 Mesoporous Molecular Sieves Institute of Scientific and Technical Information of China (English) 2001-01-01 Zirconium monohydride bonded to the framework oxygen of MCM-41 surface was prepared by the reaction of tetraneopentyl zirconium with MCM-41 surface hydroxyl groups, followed by the hydrogenolysis of the resulted product. The surface hydride was characterized by using infrared spectroscopy, solid-state NMR, elemental analysis, gas-phase chromatography and chemical probing reaction. It was shown that this surface species is stable below 150 ℃ and can catalytically crack alkanes into methane and ethane at 100 ℃. 19. METHOD AND APPARATUS FOR MAKING URANIUM-HYDRIDE COMPACTS Science.gov (United States) Wellborn, W.; Armstrong, J.R. 1959-03-10 A method and apparatus are presented for making compacts of pyrophoric hydrides in a continuous operation out of contact with air. It is particularly useful for the preparation of a canned compact of uranium hydride possessing high density and purity. The metallic uranium is enclosed in a container, positioned in a die body evacuated and nvert the uranium to the hydride is admitted and the container sealed. Heat is applied to bring about the formation of the hydride, following which compression is used to form the compact sealed in a container ready for use. 20. Microstructural studies and crystallographic orientation of different zones and δ-hydrides in resistance welded Zircaloy-4 sheets Science.gov (United States) Kiran Kumar, N. A. P.; Szpunar, Jerzy. A.; He, Zhang 2011-07-01 The cold worked stress relieved (CWSR) Zircaloy-4 sheet used as endplate in nuclear fuel bundle is resistance welded with an endcap in argon environment. Later the welded sample is hydrided in a gaseous atmosphere at 400 °C. Optical microscopy (OM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) were used to examine the morphology and crystal orientation of the hydrides. The microstructural changes in different areas of the weld zone, heat affected zone (HAZ) and the as-received zone were analyzed using EBSD technique. Optical examination showed complete random morphological orientation of hydrides and predominantly basket-weave structure in the weld zone, with very few colonies of parallel plate structures. Variant selection for α-phase formation inside prior β-grains was identified at the weld centre. As we move from the weld centre to the as-received zone, the variant selection is found to be less probable. The δ-hydride platelets at the weld zone were always found to be growing perpendicular to the α-colonies having angular difference of 60-63° and follow (0 0 0 1) α-Zr//{1 1 1}δ-ZrH 1.5 orientation relationship with the zirconium matrix. Proposed description of complex distribution of hydrides and alloy microstructure at the weld and heat affected zone will contribute to a better understanding of mechanisms of failure of fuel cladding in various types of nuclear reactors. 1. Aluminum Target Dissolution in Support of the Pu-238 Program Energy Technology Data Exchange (ETDEWEB) McFarlane, Joanna [ORNL; Benker, Dennis [ORNL; DePaoli, David W [ORNL; Felker, Leslie Kevin [ORNL; Mattus, Catherine H [ORNL 2014-09-01 Selection of an aluminum alloy for target cladding affects post-irradiation target dissolution and separations. Recent tests with aluminum alloy 6061 yielded greater than expected precipitation in the caustic dissolution step, forming up to 10 wt.% solids of aluminum hydroxides and aluminosilicates. We present a study to maximize dissolution of aluminum metal alloy, along with silicon, magnesium, and copper impurities, through control of temperature, the rate of reagent addition, and incubation time. Aluminum phase transformations have been identified as a function of time and temperature, using X-ray diffraction. Solutions have been analyzed using wet chemical methods and X-ray fluorescence. These data have been compared with published calculations of aluminum phase diagrams. Temperature logging during the transients has been investigated as a means to generate kinetic and mass transport data on the dissolution process. Approaches are given to enhance the dissolution of aluminum and aluminosilicate phases in caustic solution. 2. Topotactic Solid-State Metal Hydride Reductions of Sr2MnO4. Science.gov (United States) Hernden, Bradley C; Lussier, Joey A; Bieringer, Mario 2015-05-01 We report novel details regarding the reactivity and mechanism of the solid-state topotactic reduction of Sr2MnO4 using a series of solid-state metal hydrides. Comprehensive details describing the active reducing species are reported and comments on the reductive mechanism are provided, where it is shown that more than one electron is being donated by H(-). Commonly used solid-state hydrides LiH, NaH, and CaH2, were characterized in terms of reducing power. In addition the unexplored solid-state hydrides MgH2, SrH2, and BaH2 are evaluated as potential solid-state reductants and characterized in terms of their reductive reactivities. These 6 group I and II metal hydrides show the following trend in terms of reactivity: MgH2 < SrH2 < LiH ≈ CaH2 ≈ BaH2 < NaH. The order of the reductants are discussed in terms of metal electronegativity and bond strengths. NaH and the novel use of SrH2 allowed for targeted synthesis of reduced Sr2MnO(4-x) (0 ≤ x ≤ 0.37) phases. The enhanced control during synthesis demonstrated by this soft chemistry approach has allowed for a more comprehensive and systematic evaluation of Sr2MnO(4-x) phases than previously reported phases prepared by high temperature methods. Sr2MnO3.63(1) has for the first time been shown to be monoclinic by powder X-ray diffraction and the oxidative monoclinic to tetragonal transition occurs at 450 °C. PMID:25894860 3. Effects of Hydride Precipitation on the Stress Developed in ZrO2 Thin Film International Nuclear Information System (INIS) It has been reported that the effect of thermal redistribution of hydrides across the metal-oxide interface, coupled with thermal feedback on the metal-oxide interface, is a dominating factor in the accelerated oxidation in zirconium alloys cladding PWR fuel. Especially the precipitated and redistributed hydrides are known to relieve the stress imposed onto the metal/oxide interface during the waterside corrosion of zirconium alloys. Without the hydrides the stress exceeds the critical value of 3 GPa which induce the tetragonal ZrO2 phase formation. Therefore, in this study enhanced oxidation due to the precipitated hydrides are experimentally confirmed and stress on the interface is measured with steam beam apparatus in order to support hypothesis hydrides precipitates relieve the stress. In steam beam apparatus, Oxidation reaction occurs only the surface exposed to the steam beam. In order to avoid the oxidation of the other side of specimen, whole chamber is evacuated down to ultra-high vacuum (down to 10-5 Torr). The oxide thickness is measured with weight gain measurement and the curvature of the single side oxidized specimen is measured with spherometer. Specimen is thin film zirconium foil whose thickness is 40μm and diameter is 20mm. Only single surface of specimen exposed to the steam beam oxidizes at 400 .deg. C which is attained by halogen lamp. Basically the measurement technique used in this study is based on the curvature build-up during the single side oxidation process. The stress build-up can be directly evaluated according to the Stoney's formula. Measured stress from the curvature estimation are plotted as a function of thin oxide film thickness. And atmospheric oxidation was also carried out in the electric furnace using the specimen holder, which is designed to protect the other side oxidation of specimen. The stress in the oxide increases as the thickness decreases and the highest stress measured in this study is 5.2 GPa which is higher than 4. Rapid Microwave Synthesis, Characterization and Reactivity of Lithium Nitride Hydride, Li4NH Directory of Open Access Journals (Sweden) Nuria Tapia-Ruiz 2013-11-01 Full Text Available Lithium nitride hydride, Li4NH, was synthesised from lithium nitride and lithium hydride over minute timescales, using microwave synthesis methods in the solid state for the first time. The structure of the microwave-synthesised powders was confirmed by powder X-ray diffraction [tetragonal space group I41/a; a = 4.8864(1 Å, c = 9.9183(2 Å] and the nitride hydride reacts with moist air under ambient conditions to produce lithium hydroxide and subsequently lithium carbonate. Li4NH undergoes no dehydrogenation or decomposition [under Ar(g] below 773 K. A tetragonal–cubic phase transition, however, occurs for the compound at ca. 770 K. The new high temperature (HT phase adopts an anti-fluorite structure (space group Fm 3̅ m; a = 4.9462(3 Å with N3− and H− ions disordered on the 4a sites. Thermal treatment of Li4NH under nitrogen yields a stoichiometric mixture of lithium nitride and lithium imide (Li3N and Li2NH respectively. 5. High energy density battery based on complex hydrides Science.gov (United States) Zidan, Ragaiy 2016-04-26 A battery and process of operating a battery system is provided using high hydrogen capacity complex hydrides in an organic non-aqueous solvent that allows the transport of hydride ions such as AlH.sub.4.sup.- and metal ions during respective discharging and charging steps. 6. Ultra-sonic observation in niobium hydride precipitation International Nuclear Information System (INIS) The hidrogen embrittlement of exothermic ocluders, had been considered as due to applied stress induced hydride precipitates leading to brittle fracture. The results of simultaneous measurements of macroscopic deformation and elastic change due to hydride precipitation, using the ultrasonic pulse-echo technique are showed. THen it was tested the possibility of kinectis precipitation parameters evoluation. (Author) 7. Size Controlled Synthesis of Germanium Nanocrystals: Effect of Ge Precursor and Hydride Reducing Agent Directory of Open Access Journals (Sweden) Darragh Carolan 2015-01-01 Full Text Available Germanium nanocrystals (Ge NCs have attracted increasing attention as a promising alternative to II–VI and IV–VI semiconductor materials as they are cheap, “green,” electrochemically stable, and compatible with existing CMOS processing methods. Germanium is a particularly attractive material for optoelectronic applications as it combines a narrow band gap with high carrier mobilities and a large exciton Bohr radius. Solution-phase synthesis and characterisation of size monodisperse alkyl-terminated Ge NCs are demonstrated. Ge NCs were synthesised under inert atmospheric conditions via the reduction of Ge halide salts (GeX4 by hydride reducing agents within inverse micelles. Regulation of NC size is achieved by variation of germanium precursor and the strength of hydride reducing agents used. UV-Visible absorbance and photoluminescence spectroscopy showed strong significant quantum confinement effects, with moderate absorption in the UV spectral range, and strong emission in the violet with a marked dependence on excitation wavelength. 8. The Microstructure and Properties of Diffusion Layer of Spray Aluminum Institute of Scientific and Technical Information of China (English) YE Hong; YAN Zhonglin; SUN Zhifu 2005-01-01 After diffusion processing of thermal spraying, aluminum on 20 # steel is discussed in this article. Variations of microstructure, composition as well as microhardness and corrosion resistance of diffusion layer of spray aluminum were explored by means of X- ray diffraction, scanning electron microscopy (SEM) and electron probe microanalysis ( EPMA ). The result shows that the diffusion layer of spray aluminum consists of η phase ( Fe2 Al5 ), ζ phase ( FeAl2 ), β1 phase ( Fe3Al ), β1 phase ( Fe3 Al ) and α phase from surface to substrate. There are balanced transitions between phases. The layer has extra high hardncss and corrosion resistance. 9. Modular hydride beds for mobile applications Energy Technology Data Exchange (ETDEWEB) Malinowski, M.E.; Stewart, K.D. 1997-08-01 Design, construction, initial testing and simple thermal modeling of modular, metal hydride beds have been completed. Originally designed for supplying hydrogen to a fuel cell on a mobile vehicle, the complete bed design consists of 8 modules and is intended for use on the Palm Desert Vehicle (PDV) under development at the Schatz Energy Center, Humbolt State University. Each module contains approximately 2 kg of a commercially available, low temperature, hydride-forming metal alloy. Waste heat from the fuel cell in the form of heated water is used to desorb hydrogen from the alloy for supplying feed hydrogen to the fuel cell. In order to help determine the performance of such a modular bed system, six modules were constructed and tested. The design and construction of the modules is described in detail. Initial testing of the modules both individually and as a group showed that each module can store {approximately} 30 g of hydrogen (at 165 PSIA fill pressure, 17 C), could be filled with hydrogen in 6 minutes at a nominal, 75 standard liters/min (slm) fueling rate, and could supply hydrogen during desorption at rates of 25 slm, the maximum anticipated hydrogen fuel cell input requirement. Tests made of 5 modules as a group indicated that the behavior of the group run in parallel both in fueling and gas delivery could be directly predicted from the corresponding, single module characteristics by using an appropriate scaling factor. Simple thermal modeling of a module as an array of cylindrical, hydride-filled tubes was performed. The predictions of the model are in good agreement with experimental data. 10. Preferred hydride growth orientations on oxide-coated gadolinium surfaces International Nuclear Information System (INIS) Highlights: ► The preferred hydride growth orientations on gadolinium metal coated by a thin oxide layer are presented. ► A preferred growth of the (1 0 0)h plane of the face centered cubic (FCC) GdH2 is observed for the hydride spots forming below the oxidation layer. ► A change to the (1 1 1)h plane of the cubic hydride dominates for the hydride's Growth Centers. ► The texture change is attributed to the surface normal compressive stress component exerted by the oxidation layer on the developing hydride. - Abstract: The initial development of hydrides on polycrystalline gadolinium (Gd), as on some other hydride forming metals, is characterized by two sequential steps. The first step involves the rapid formation of a dense pattern of small hydride spots (referred to as the “small family” of hydrides) below the native oxidation layer. The second stage takes place when some of the “small family” nucleants (referred to as “growth centers”, GCs) break the oxide layer, leading to their rapid growth and finally to the massive hydriding of the sample. In the present study, the texture of the two hydride families was studied, by combining X-ray diffraction (XRD) analysis with a microscopic analysis of the hydride, using scanning electron microscopy (SEM) and atomic force microscopy (AFM). It has been observed that for the “small family”, a preferred growth of the (1 0 0)h plane of the cubic GdH2 takes place, whereas for the GCs, a change to the (1 1 1)h plane of the cubic hydride dominates. These preferred growth orientations were analyzed by their structure relation with the (0 0 .1)m basal plane of the Gd metal. It has been concluded that the above texture change is due to the surface normal compressive stress component exerted by the oxidation overlayer on the developing hydride, preventing the (0 0 .1)m||(1 1 1)h growth orientation. This stress is relieved upon the rupture of that overlayer and the development of the GCs, leading to the 11. Low-frequency excitations in zirconium hydrides International Nuclear Information System (INIS) The slow inelastic neutron scattering (INS) on ZrHx systems (x = 0.38, 0.52) revealed new excitations located within the energy range 2-10 MeV. Besides the acoustic vibrations specific to α-HCP Zr and γ-FCO Zr hydride the fine structure of these excitations is clearly observed. The origin of the new observed peaks is not very clear but a proton tunneling or a resonance effect in α-Zr lattice could be taken into account 12. Tritium immobilization and packaging using metal hydrides International Nuclear Information System (INIS) Tritium recovered from CANDU heavy water reactors will have to be packaged and stored in a safe manner. Tritium will be recovered in the elemental form, T2. Metal tritides are effective compounds in which to immobilize the tritium as a stable non-reactive solid with a high tritium capacity. The technology necessary to prepare hydrides of suitable metals, such as titanium and zirconium, have been developed and the properties of the prepared materials evaluated. Conceptual designs of packages for containing metal tritides suitable for transportation and long-term storage have been made and initial testing started. (author) 13. Metal hydrides for concentrating solar thermal power energy storage Science.gov (United States) Sheppard, D. A.; Paskevicius, M.; Humphries, T. D.; Felderhoff, M.; Capurso, G.; Bellosta von Colbe, J.; Dornheim, M.; Klassen, T.; Ward, P. A.; Teprovich, J. A.; Corgnale, C.; Zidan, R.; Grant, D. M.; Buckley, C. E. 2016-04-01 The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost of concentrating solar thermal power. We focus on the underlying technology that allows metal hydrides to function as thermal energy storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room temperature and as high as 1100 °C. The potential of metal hydrides for thermal storage is explored, while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature TES are also addressed. 14. Recent advances in metal hydrides for clean energy applications Energy Technology Data Exchange (ETDEWEB) Ronnebro, Ewa; Majzoub, Eric H. 2013-06-01 Metal hydrides are a fascinating class of materials that can be utilized for a surprising variety of clean energy applications, including smart solar collectors, smart windows, sensors, thermal energy storage, and batteries, in addition to their traditional application for hydrogen storage. Over the past decade, research on metal hydrides for hydrogen storage increased due to global governmental incentives and an increased focus on hydrogen storage research for polymer electrolyte membrane fuel cell operation. Tremendous progress has been made in so-called complex metal hydrides for hydrogen storage applications with the discovery of many new hydrides containing covalently bound complex anions. Many of these materials have applications beyond hydrogen storage and are being investigated for lithium-ion battery separator and anode materials. In this issue of MRS Bulletin , we present the state of the art of key evolving metal-hydride-based clean energy technologies with an outlook toward future needs. 15. Helium trapping at erbium oxide precipitates in erbium hydride Energy Technology Data Exchange (ETDEWEB) Foiles, Stephen M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Battaile, Corbett Chandler [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States) 2016-02-01 The formation of He bubbles in erbium tritides is a significant process in the aging of these materials. Due to the long-standing uncertainty about the initial nucleation process of these bubbles, there is interest in mechanisms that can lead to the localization of He in erbium hydrides. Previous work has been unable to identify nucleation sites in homogeneous erbium hydride. This work builds on the experimental observation that erbium hydrides have nano- scale erbium oxide precipitates due to the high thermodynamic stability of erbium oxide and the ubiquitous presence of oxygen during materials processing. Fundamental DFT calculations indicate that the He is energetically favored in the oxide relative to the bulk hydride. Activation energies for the motion of He in the oxide and at the oxide-hydride interface indicate that trapping is kinetically feasible. A simple kinetic Monte Carlo model is developed that demonstrates the degree of trapping of He as a function of temperature and oxide fraction. 16. Bonding in Zintl phase hydrides: density functional calculations for SrAlSiH, SrAl2H2, SrGa2H2 and BaGa2H2 Energy Technology Data Exchange (ETDEWEB) Subedi, Alaska P [ORNL; Singh, David J [ORNL 2008-01-01 We investigate the bonding characteristics of SrAlSiH, SrAl{sub 2}H{sub 2}, SrGa{sub 2}H{sub 2}, and BaGa{sub 2}H{sub 2} using density functional calculations. The mixed bonding characteristic of other families of Zintl phases is found, with the formation of covalent sp{sup 2} bonds in the Al/Ga/Al-Si planes of the various compounds. On the other hand the Sr and Ba atoms occur as divalent cations, while the H is anionic. The results indicate that insulating SrSiAlH may be a switchable ferroelectric. 17. Noble-gas hydrides: new chemistry at low temperatures. Science.gov (United States) Khriachtchev, Leonid; Räsänen, Markku; Gerber, R Benny 2009-01-20 Noble-gas chemistry has been undergoing a renaissance in recent years, due in large part to noble-gas hydrides, HNgY, where Ng = noble-gas atom and Y = electronegative fragment. These molecules are exceptional because of their relatively weak bonding and large dipole moments, which lead to strongly enhanced effects of the environment, complexation, and reactions. In this Account, we discuss the matrix-isolation synthesis of noble-gas hydrides, their spectroscopic and structural properties, and their stabilities.This family of species was discovered in 1995 and now has 23 members that are prepared in noble-gas matrices (HXeBr, HKrCl, HXeH, HXeOH, HXeO, etc.). The preparations of the first neutral argon molecule, HArF, and halogen-free organic noble-gas molecules (HXeCCH, HXeCC, HKrCCH, etc.) are important highlights of the field. These molecules are formed by the neutral H + Ng + Y channel. The first addition reaction involving HNgY molecules was HXeCC + Xe + H --> HXeCCXeH, and this led to the first hydride with two noble-gas atoms (recently extended by HXeOXeH). The experimental synthesis of HNgY molecules starts with production of H and Y fragments in solid noble gas via the UV photolysis of suitable precursors. The HNgY molecules mainly form upon thermal mobilization of the fragments.One of the unusual properties of these molecules is the hindered rotation of some HNgY molecules in solid matrices; this has been theoretically modeled. HNgY molecules also have unusual solvation effects, and the H-Xe stretching mode shifts to higher frequencies (up to about 150 cm-1) upon interaction with other species.The noble hydrides have a new bonding motif: HNgY molecules can be represented in the form (H-Ng)+Y-, where (H-Ng)+ is mainly covalent, whereas the interaction between (HNg)+ and Y- is predominantly ionic. The HNgY molecules are highly metastable species representing high-energy materials. The decomposition process HNgY --> Ng + HY is always strongly exoergic 18. A model to describe the mechanical behavior and the ductile failure of hydrided Zircaloy-4 fuel claddings between 25 °C and 480 °C Science.gov (United States) Le Saux, M.; Besson, J.; Carassou, S. 2015-11-01 A model is proposed to describe the mechanical behavior and the ductile failure at 25, 350 and 480 °C of Zircaloy-4 cladding tubes, as-received and hydrided up to 1200 wt. ppm (circumferential hydrides). The model is based on the Gurson-Tvergaard-Needleman model extended to account for plastic anisotropy and viscoplasticity. The model considers damage nucleation by both hydride cracking and debonding of the interface between the Laves phase precipitates and the matrix. The damage nucleation rate due to hydride cracking is directly deduced from quantitative microstructural observations. The other model parameters are identified from several experimental tests. Finite element simulations of axial tension, hoop tension, expansion due to compression and hoop plane strain tension experiments are performed to assess the model prediction capability. The calibrated model satisfactorily reproduces the effects of hydrogen and temperature on both the viscoplastic and the failure properties of the material. The results suggest that damage is anisotropic and influenced by the stress state for the non-hydrided or moderately hydrided material and becomes more isotropic for high hydrogen contents. 19. Development of hydride absorber for fast reactor. Application of hafnium hydride to control rod of large fast reactor International Nuclear Information System (INIS) The application of hafnium hydride (Hf-hydride) to a control rod for a large fast reactor where the B4C control rod is originally employed is studied. Three types of Hf-hydride control rods are designed. The control rod worth and its change during the burnup are evaluated for different hydrogen-to-hafnium ratios and are compared with those of the original B4C control rod. The result indicates that the worths of the Hf-hydride and the 10B-enriched B4C control rods are approximately the same, and the lifetime of the Hf-hydride control rod is almost four times longer than that of the 10B-enriched B4C control rod. The core performances of the shutdown margin, sodium void reactivity, Doppler reactivity coefficient, and breeding ratio are analyzed. It is indicated that those for the Hf-hydride control rod are almost the same as those for the original B4C control rod. The behavior of neutrons moderated by the Hf-hydride control rod is analyzed. It is confirmed that the Hf-hydride control rod does not cause any thermal spike problems in the fast reactor core. (author) 20. Development of high-capacity nickel-metal hydride batteries using superlattice hydrogen-absorbing alloys International Nuclear Information System (INIS) New R-Mg-Ni (R: rare earths) superlattice alloys with higher-capacity and higher-durability than the conventional Mm-Ni alloys with CaCu5 structure have been developed. The oxidation resistibility of the superlattice alloys has been improved by optimizing the alloy composition by such as substituting aluminum for nickel and optimizing the magnesium content in order to prolong the battery life. High-capacity nickel-metal hydride batteries for the retail market, the Ni-MH2500/900 series (AA size type 2500mAh, AAA size type 900mAh), have been developed and commercialized by using an improved superlattice alloy for negative electrode material. alized by using an improved superlattice alloy for negative electrode material. (author) 1. Rheology of suspensions with aluminum nano-particles Directory of Open Access Journals (Sweden) Ulrich Teipel 2009-01-01 Full Text Available Nano-scale aluminum particles are innovative materials increasingly used in energetic formulations. In this contribution, the rheological behavior of suspensions with either paraffin oil or HTPB as the matrix fluid and nano-scale aluminum (ALEX as the dispersed phase is described and discussed. The paraffin oil/aluminum suspensions exhibit non-Newtonian flow behavior over a wide range of concentrations, whereas the HTPB/aluminum suspensions exhibitNewtonian behavior (i.e. the viscosity is independent of shear stress up to a concentration of 50 vol.% aluminum. Both systems have unusual viscoelastic properties in that their elastic moduli are independent of the solids concentration. 2. NATO Advanced Study Institute on Metal Hydrides CERN Document Server 1981-01-01 In the last five years, the study of metal hydrides has ex panded enormously due to the potential technological importance of this class of materials in hydrogen based energy conversion schemes. The scope of this activity has been worldwide among the industrially advanced nations. There has been a consensus among researchers in both fundamental and applied areas that a more basic understanding of the properties of metal/hydrogen syster;,s is required in order to provide a rational basis for the selection of materials for specific applications. The current worldwide need for and interest in research in metal hydrides indicated the timeliness of an Advanced Study Insti tute to provide an in-depth view of the field for those active in its various aspects. The inclusion of speakers from non-NATO coun tries provided the opportunity for cross-fertilization of ideas for future research. While the emphasis of the Institute was on basic properties, there was a conscious effort to stimulate interest in the applic... 3. Complex Hydride Compounds with Enhanced Hydrogen Storage Capacity Energy Technology Data Exchange (ETDEWEB) Mosher, Daniel A.; Opalka, Susanne M.; Tang, Xia; Laube, Bruce L.; Brown, Ronald J.; Vanderspurt, Thomas H.; Arsenault, Sarah; Wu, Robert; Strickler, Jamie; Anton, Donald L.; Zidan, Ragaiy; Berseth, Polly 2008-02-18 The United Technologies Research Center (UTRC), in collaboration with major partners Albemarle Corporation (Albemarle) and the Savannah River National Laboratory (SRNL), conducted research to discover new hydride materials for the storage of hydrogen having on-board reversibility and a target gravimetric capacity of ≥ 7.5 weight percent (wt %). When integrated into a system with a reasonable efficiency of 60% (mass of hydride / total mass), this target material would produce a system gravimetric capacity of ≥ 4.5 wt %, consistent with the DOE 2007 target. The approach established for the project combined first principles modeling (FPM - UTRC) with multiple synthesis methods: Solid State Processing (SSP - UTRC), Solution Based Processing (SBP - Albemarle) and Molten State Processing (MSP - SRNL). In the search for novel compounds, each of these methods has advantages and disadvantages; by combining them, the potential for success was increased. During the project, UTRC refined its FPM framework which includes ground state (0 Kelvin) structural determinations, elevated temperature thermodynamic predictions and thermodynamic / phase diagram calculations. This modeling was used both to precede synthesis in a virtual search for new compounds and after initial synthesis to examine reaction details and options for modifications including co-reactant additions. The SSP synthesis method involved high energy ball milling which was simple, efficient for small batches and has proven effective for other storage material compositions. The SBP method produced very homogeneous chemical reactions, some of which cannot be performed via solid state routes, and would be the preferred approach for large scale production. The MSP technique is similar to the SSP method, but involves higher temperature and hydrogen pressure conditions to achieve greater species mobility. During the initial phases of the project, the focus was on higher order alanate complexes in the phase space 4. ALUMINUM BOX BUNDLING PRESS Directory of Open Access Journals (Sweden) Iosif DUMITRESCU 2015-05-01 Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling. 5. Isotope exchange between gaseous hydrogen and uranium hydride powder International Nuclear Information System (INIS) Highlights: • Isotope exchange between hydrogen gas and uranium hydride powder can be rapid and reversible. • Gas–solid exchange rate is controlled by transport within ∼0.7 μm hydride particles. • Gas chromatographic separation of hydrogen isotopes using uranium hydride is feasible. - Abstract: Isotope exchange between gaseous hydrogen and solid uranium hydride has been studied by flowing hydrogen (deuterium) gas through packed powder beds of uranium deuteride (hydride). We used a residual gas analyzer system to perform real-time analysis of the effluent gas composition. We also developed an exchange and transport model and, by fitting it to the experimental data, extracted kinetic parameters for the isotope exchange reaction. Our results suggest that, from approximately 70 to 700 kPa and 25 to 400 °C, the gas-to-solid exchange rate is controlled by hydrogen and deuterium transport within the ∼0.7 μm diameter uranium hydride particles. We use our kinetic parameters to show that gas chromatographic separation of hydrogen and deuterium using uranium hydride could be feasible 6. The role of chemical free energy and elastic strain in the nucleation of zirconium hydride Energy Technology Data Exchange (ETDEWEB) Barrow, A.T.W. [Nuclear Materials Group, Department of Mechanical and Materials Engineering, Queen’s University, Kingston, Ontario K7L 3N6 (Canada); Toffolon-Masclet, C. [CEA-Saclay, Nuclear Materials Department, SRMA/LA2M, F-91191 Gif-Sur-Yvette (France); Almer, J. [Argonne National Laboratory, Argonne, IL 60439 (United States); Daymond, M.R., E-mail: daymond@me.queensu.ca [Nuclear Materials Group, Department of Mechanical and Materials Engineering, Queen’s University, Kingston, Ontario K7L 3N6 (Canada) 2013-10-15 In this work a combination of synchrotron X-ray diffraction and thermodynamic modelling has been used to study the dissolution and precipitation of zirconium hydride in α-Zr establishing the role of elastic misfit strain and chemical free energy in the α → α + δ phase transformation. The nucleation of zirconium hydride is dominated by the chemical free energy where the chemical driving force for hydride precipitation is proportional to the terminal-solid solubility for precipitation and can be predicted by a function that is analogous to the universal nucleation parameter for the bainite transformation in ferrous alloys. The terminal-solid solubility for precipitation was found to be kinetically limited ⩾287 °C at a cooling rate of 5 °C min{sup −1} or greater. The terminal solubilities were established using an offset method applied to the lattice strain data where a resolution of ∼10 wppm H can be achieved in the 〈c〉-direction. This is aided by the introduction of intra-granular strains in the 〈c〉-direction during cooling as a result of the thermal expansion anisotropy which increases the anisotropy associated with the misfitting H atoms within the α-Zr lattice. 7. Equation of state of palladium hydride and deuteride to 100 GPa Science.gov (United States) Brownsberger, Keenan; Ahart, Muhtar; Somayazulu, Maddury; Gramsch, Stephen; Hemley, Russell To study the behavior of palladium hydrides under pressure, we loaded palladium foils in hydrogen or deuterium environments in two separate diamond anvil cells. We subsequently measured x-ray diffraction up to 100 GPa at room temperature. No structural phase transition was observed for either PdDx or PdHx between 0 GPa and 100 GPa. The pressure-volume data were fitted with the third-order Birch-Murnaghan equation of state, which gave an initial volume of 10.8 cm3/mol, a bulk modulus of 153 GPa, and its derivative of 4.3 for palladium hydride. An initial volume of 10.6 cm3/mol, a bulk modulus of 162 GPa, and its pressure derivative of 4.6 were determined for palladium deuteride. From initial volumes, we conclude that x =1 for both PdDx and PdHx. This work is supported by the Carnegie-DOE Alliance Center. EOS of palladium hydride and deuteride to 100 GPa. 8. Hydrogen storage in metal hydrides and complex hydrides; Wasserstoffspeicherung in Metall- und komplexen Hydriden - Schlussbericht Energy Technology Data Exchange (ETDEWEB) Bielmann, M.; Zuettel, A. 2007-07-01 This final report for the Swiss Federal Office of Energy (SFOE), reports on work done in 2007 at the Swiss Federal Laboratories for Materials Science and Technology EMPA on the storage of hydrogen in metal hydrides and complex hydrides. In particular, the use of tetrahydroborates is noted. The potential of this class of materials is stressed. The structures at room-temperature were examined using neutron and X-ray diffraction methods. Thermodynamic methods helped determine the thermodynamic stability of the materials. Also, a complete energy diagram for the materials was developed. The use of silicon oxide to reduce activation energy and its catalytic effects are discussed. The challenges placed by desorption mechanisms are noted. The authors note that reversibility is basically proven. 9. Develop improved metal hydride technology for the storage of hydrogen. Final technical report Energy Technology Data Exchange (ETDEWEB) Sapru, K. 1998-12-04 The overall objective was to develop commercially viable metal hydrides capable of reversibly storing at least 3 wt.% hydrogen for use with PEM fuel cells and hydrogen fueled internal combustion engine (HICE) applications. Such alloys are expected to result in system capacities of greater than 2 wt.%, making metal hydride storage systems (MHSSs) a practical means of supplying hydrogen for many consumer applications. ECDs (Energy Conversion Devices, Inc.) past work on sputtered thin films of transition metal-based alloys led to the commercialization of its nickel/metal hydride batteries, and similar work on thin film Mg-based alloys demonstrated potential to achieve very high gravimetric and volumetric energy densities approaching 2,500 Wh/Kg and 2,500 Wh/M{sup 3} respectively. Under this 2-year cost shared project with the DOE, the authors have successfully demonstrated the feasibility of scaling up the Mg-based hydrides from thin film to bulk production without substantial loss of storage capacity. ECD made progress in alloy development by means of compositional and process modification. Processes used include Mechanical Alloying, Melt spinning and novel Gas Phase Condensation. It was showed that the same composition when prepared by melt-spinning resulted in a more homogeneous material having a higher PCT plateau pressure as compared to mechanical alloying. It was also shown that mechanically alloyed Mg-Al-Zn results in much higher plateau pressures, which is an important step towards reducing the desorption temperature. While significant progress has been made during the past two years in alloy development and understanding the relationship between composition, structure, morphology, and processing parameters, additional R and D needs to be performed to achieve the goals of this work. 10. PIE techniques for hydride reorientation test at NDC International Nuclear Information System (INIS) Dry storage of spent fuels in the interim storage facility is being planned in Japan. However, the gradual deterioration of the mechanical property of fuel cladding due to internal pressure and temperature during the storage term is known. Therefore, the integrity of stored fuel rods should be confirmed before the start of dry storage. For the last several years, NDC had a lot of experiences on the hydride reorientation test. The specimen preparation techniques on the hydride reorientation test and the mechanical testing techniques after the hydride reorientation are shown in this paper. (author) 11. Development of delayed hydride cracking resistant-pressure tube Energy Technology Data Exchange (ETDEWEB) Kim, Young Suk; Kwon, Sang Chul; Kim, S. S.; Yim, K. S 2000-10-01 For the first time, we demonstrate that the pattern of nucleation and growth of a DHC crack is governed by the precipitation of hydrides so that the DHC velocity and K{sub IH} are determined by an angle of the cracking plane and the hydride habit plane 10.7. Since texture controls the distribution of the 10.7 habit plane in Zr-2.5Nb pressure tube, we draw a conclusion that a textural change in Zr-2.5Nb tube from a strong tangential texture to the radial texture shall increase the threshold stress intensity factor, K{sub IH}, and decrease the delayed hydride cracking velocity. This conclusion is also verified by a complimentary experiment showing a linear dependence of DHCV and K{sub IH} with an increase in the basal component in the cracking plane. On the basis of the study on the DHC mechanism and the effect of manufacturing processes on the properties of Zr-2.5Nb tube, we have established a manufacturing procedure to make pressure tubes with improved DHC resistance. The main features of the established manufacturing process consist in the two step-cold pilgering process and the intermediate heat treatment in the {alpha} + {beta} phase for Zr-2.5Nb alloy and in the {alpha} phase for Zr-1Nb-1.2Sn-0.4Fe alloy. The manufacturing of DHC resistant-pressure tubes of Zr-2.5Nb and Zr-1N-1.2Sn-0.4Fe was made in the ChMP zirconium plant in Russia under a joint research with Drs. Nikulina and Markelov in VNIINM (Russia). Zr-2.5Nb pressure tube made with the established manufacturing process has met all the specification requirements put by KAERI. Chracterization tests have been jointly conducted by VNIINM and KAERI. As expected, the Zr-2.5Nb tube made with the established procedure has improved DHC resistance compared to that of CANDU Zr-2.5Nb pressure tube used currently. The measured DHC velocity of the Zr-2.5Nb tube meets the target value (DHCV <5x10{sup -8} m/s) and its other properties also were equivalent to those of the CANDU Zr-2.5Nb tube used currently. The Zr-1Nb-1 12. Graphene-aluminum nanocomposites International Nuclear Information System (INIS) Highlights: → We investigated the mechanical properties of aluminum and aluminum nanocomposites. → Graphene composite had lower strength and hardness compared to nanotube reinforcement. → Processing causes aluminum carbide formation at graphene defects. → The carbides in between grains is a source of weakness and lowers tensile strength. - Abstract: Composites of graphene platelets and powdered aluminum were made using ball milling, hot isostatic pressing and extrusion. The mechanical properties and microstructure were studied using hardness and tensile tests, as well as electron microscopy, X-ray diffraction and differential scanning calorimetry. Compared to the pure aluminum and multi-walled carbon nanotube composites, the graphene-aluminum composite showed decreased strength and hardness. This is explained in the context of enhanced aluminum carbide formation with the graphene filler. 13. Graphene-aluminum nanocomposites Energy Technology Data Exchange (ETDEWEB) Bartolucci, Stephen F., E-mail: stephen.bartolucci@us.army.mil [U.S. Army Benet Laboratories, Armaments Research Development and Engineering Center, Watervliet, NY 12189-4000 (United States); Paras, Joseph [U.S. Army Benet Laboratories, Armaments Research Development and Engineering Center, Watervliet, NY 12189-4000 (United States); Rafiee, Mohammad A. [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005 (United States); Rafiee, Javad [Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lee, Sabrina; Kapoor, Deepak [U.S. Army Benet Laboratories, Armaments Research Development and Engineering Center, Watervliet, NY 12189-4000 (United States); Koratkar, Nikhil, E-mail: koratn@rpi.edu [Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States) 2011-10-15 Highlights: {yields} We investigated the mechanical properties of aluminum and aluminum nanocomposites. {yields} Graphene composite had lower strength and hardness compared to nanotube reinforcement. {yields} Processing causes aluminum carbide formation at graphene defects. {yields} The carbides in between grains is a source of weakness and lowers tensile strength. - Abstract: Composites of graphene platelets and powdered aluminum were made using ball milling, hot isostatic pressing and extrusion. The mechanical properties and microstructure were studied using hardness and tensile tests, as well as electron microscopy, X-ray diffraction and differential scanning calorimetry. Compared to the pure aluminum and multi-walled carbon nanotube composites, the graphene-aluminum composite showed decreased strength and hardness. This is explained in the context of enhanced aluminum carbide formation with the graphene filler. 14. Insight into the kinetics and thermodynamics of the hydride transfer reactions between quinones and lumiflavin: a density functional theory study. Science.gov (United States) Reinhardt, Clorice R; Jaglinski, Tanner C; Kastenschmidt, Ashly M; Song, Eun H; Gross, Adam K; Krause, Alyssa J; Gollmar, Jonathan M; Meise, Kristin J; Stenerson, Zachary S; Weibel, Tyler J; Dison, Andrew; Finnegan, Mackenzie R; Griesi, Daniel S; Heltne, Michael D; Hughes, Tom G; Hunt, Connor D; Jansen, Kayla A; Xiong, Adam H; Hati, Sanchita; Bhattacharyya, Sudeep 2016-09-01 The kinetics and equilibrium of the hydride transfer reaction between lumiflavin and a number of substituted quinones was studied using density functional theory. The impact of electron withdrawing/donating substituents on the redox potentials of quinones was studied. In addition, the role of these substituents on the kinetics of the hydride transfer reaction with lumiflavin was investigated in detail under the transition state (TS) theory assumption. The hydride transfer reactions were found to be more favorable for an electron-withdrawing substituent. The activation barrier exhibited a quadratic relationship with the driving force of these reactions as derived under the formalism of modified Marcus theory. The present study found a significant extent of electron delocalization in the TS that is stabilized by enhanced electrostatic, polarization, and exchange interactions. Analysis of geometry, bond-orders, and energetics revealed a predominant parallel (Leffler-Hammond) effect on the TS. Closer scrutiny reveals that electron-withdrawing substituents, although located on the acceptor ring, reduce the N-H bond order of the donor fragment in the precursor complex. Carried out in the gas-phase, this is the first ever report of a theoretical study of flavin's hydride transfer reactions with quinones, providing an unfiltered view of the electronic effect on the nuclear reorganization of donor-acceptor complexes. PMID:27491848 15. Insight into the kinetics and thermodynamics of the hydride transfer reactions between quinones and lumiflavin: a density functional theory study. Science.gov (United States) Reinhardt, Clorice R; Jaglinski, Tanner C; Kastenschmidt, Ashly M; Song, Eun H; Gross, Adam K; Krause, Alyssa J; Gollmar, Jonathan M; Meise, Kristin J; Stenerson, Zachary S; Weibel, Tyler J; Dison, Andrew; Finnegan, Mackenzie R; Griesi, Daniel S; Heltne, Michael D; Hughes, Tom G; Hunt, Connor D; Jansen, Kayla A; Xiong, Adam H; Hati, Sanchita; Bhattacharyya, Sudeep 2016-09-01 The kinetics and equilibrium of the hydride transfer reaction between lumiflavin and a number of substituted quinones was studied using density functional theory. The impact of electron withdrawing/donating substituents on the redox potentials of quinones was studied. In addition, the role of these substituents on the kinetics of the hydride transfer reaction with lumiflavin was investigated in detail under the transition state (TS) theory assumption. The hydride transfer reactions were found to be more favorable for an electron-withdrawing substituent. The activation barrier exhibited a quadratic relationship with the driving force of these reactions as derived under the formalism of modified Marcus theory. The present study found a significant extent of electron delocalization in the TS that is stabilized by enhanced electrostatic, polarization, and exchange interactions. Analysis of geometry, bond-orders, and energetics revealed a predominant parallel (Leffler-Hammond) effect on the TS. Closer scrutiny reveals that electron-withdrawing substituents, although located on the acceptor ring, reduce the N-H bond order of the donor fragment in the precursor complex. Carried out in the gas-phase, this is the first ever report of a theoretical study of flavin's hydride transfer reactions with quinones, providing an unfiltered view of the electronic effect on the nuclear reorganization of donor-acceptor complexes. 16. Polytypic transformations of aluminum hydroxide: A mechanistic investigation Institute of Scientific and Technical Information of China (English) Thimmasandra Narayan Ramesh 2012-01-01 The diffusion of ammonia vapors into a solution of aluminum nitrate or ferric nitrate results in the precipitation of their respective hydroxides and oxyhydroxides.Polymorphic phase formation of aluminum hydroxide is controlled by the rate of crystallization.The PXRD patterns of products obtained via vapor phase diffusion revealed that poorly ordered aluminum hydroxide is formed during the initial stages of crystallization.After 8 days,the formation of the bayerite phase of aluminum hydroxide was observed.Upon prolonged exposure to ammonia vapors,bayerite was transformed into gibbsite.The infrared spectrum of the product confirmed the presence of different polytypic phases of aluminum hydroxide.The results demonstrated that the crystal structure of metal hydroxides is controlled by the rate of crystallization,nature of the metal ion,site selectivity and specificity and preparative conditions. 17. Artificial exomuscle investigations for applications-metal hydride International Nuclear Information System (INIS) In pursuing the development of bionic devices, Victhom identified a need for technologies that could replace current motorized systems and be better integrated into the human body motion. The actuators used to obtain large displacements are noisy, heavy, and do not adequately reproduce human muscle behavior. Subsequently, a project at Victhom was devoted to the development of active materials to obtain an artificial exomuscle actuator. An exhaustive literature review was done at Victhom to identify promising active materials for the development of artificial muscles. According to this review, metal hydrides were identified as a promising technology for artificial muscle development. Victhom's investigations focused on determining metal hydride actuator potential in the context of bionics technology. Based on metal hydride properties and artificial muscle requirements such as force, displacement and rise time, an exomuscle was built. In addition, a finite element model, including heat and mass transfer in the metal hydride, was developed and implemented in FEMLAB software. (review article) 18. Out-of-pile accelerated hydriding of Zircaloy fasteners International Nuclear Information System (INIS) Mechanical joints between Zircaloy and nickel-bearing alloys, mainly the Zircaloy-4/Inconel-600 combination, were exposed to water at 4500F and 5200F to study hydriding of Zircaloy in contact with a dissimilar metal. Accelerated hydriding of the Zircaloy occurred at both temperatures. At 4500F the dissolved hydrogen level of the water was over ten times that at 5200F. At 5200F the initially high hydrogen ingress rate decreased rapidly as exposure time increased and was effectively shut off in about 25 days. Severely hydrided Zircaloy components successfully withstood thermal cycling and mechanical testing. Chromium plating of the nickel-bearing parts was found to be an effective and practical barrier in preventing nickel-alloy smearing and accelerated hydriding of Zircaloy 19. Artificial exomuscle investigations for applications-metal hydride Energy Technology Data Exchange (ETDEWEB) Crevier, Marie-Charlotte; Richard, Martin; Rittenhouse, D Matheson; Roy, Pierre-Olivier; Bedard, Stephane [Victhom Human Bionics Inc., Saint-Augustin-de-Desmaures, QC (Canada) 2007-03-01 In pursuing the development of bionic devices, Victhom identified a need for technologies that could replace current motorized systems and be better integrated into the human body motion. The actuators used to obtain large displacements are noisy, heavy, and do not adequately reproduce human muscle behavior. Subsequently, a project at Victhom was devoted to the development of active materials to obtain an artificial exomuscle actuator. An exhaustive literature review was done at Victhom to identify promising active materials for the development of artificial muscles. According to this review, metal hydrides were identified as a promising technology for artificial muscle development. Victhom's investigations focused on determining metal hydride actuator potential in the context of bionics technology. Based on metal hydride properties and artificial muscle requirements such as force, displacement and rise time, an exomuscle was built. In addition, a finite element model, including heat and mass transfer in the metal hydride, was developed and implemented in FEMLAB software. (review article) 20. Electronic structure and optical properties of lightweight metal hydrides NARCIS (Netherlands) Setten, van M.J.; Popa, V.A.; Wijs, de G.A.; Brocks, G. 2007-01-01 We study the dielectric functions of the series of simple hydrides LiH, NaH, MgH2, and AlH3, and of the complex hydrides Li3AlH6, Na3AlH6, LiAlH4, NaAlH4, and Mg(AlH4)2, using first-principles density-functional theory and GW calculations. All compounds are large gap insulators with GW single-partic 1. Electronic structure of ternary hydrides based on light elements Energy Technology Data Exchange (ETDEWEB) Orgaz, E. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico)]. E-mail: orgaz@eros.pquim.unam.mx; Membrillo, A. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico); Castaneda, R. [Departamento de Fisica y Quimica Teorica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico); Aburto, A. [Departamento de Fisica, Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, CP 04510 Coyoacan, Mexico, D.F. (Mexico) 2005-12-08 Ternary hydrides based on light elements are interesting owing to the high available energy density. In this work we focused into the electronic structure of a series of known systems having the general formula AMH{sub 4}(A=Li,Na,M=B,Al). We computed the energy bands and the total and partial density of states using the linear-augmented plane waves method. In this report, we discuss the chemical bonding in this series of complex hydrides. 2. Thin-film metal hydrides for solar energy applications OpenAIRE 2012-01-01 Thin-film metal hydrides may become important solar energy materials in the future. This thesis demonstrates interesting material properties of metal hydride films, relevant for applications as semiconducting materials for photovoltaic (PV) solar cells and for regulation of light using smart window technology. List of papers. Papers II-VI are removed from the thesis due to copyright restrictions. Paper I C. Platzer-Björkman, T. Mongstad, S. Zh. Karazhanov, J. P. Mæhlen, E. S. Marst... 3. Method of selective reduction of polyhalosilanes with alkyltin hydrides Science.gov (United States) Sharp, Kenneth G.; D'Errico, John J. 1989-01-01 The invention relates to the selective and stepwise reduction of polyhalosilanes by reacting at room temperature or below with alkyltin hydrides without the use of free radical intermediates. Alkyltin hydrides selectively and stepwise reduce the Si--Br, Si--Cl, or Si--I bonds while leaving intact any Si--F bonds. When two or more different halogens are present on the polyhalosilane, the halogen with the highest atomic weight is preferentially reduced. 4. Method of selective reduction of halodisilanes with alkyltin hydrides Science.gov (United States) D'Errico, John J.; Sharp, Kenneth G. 1989-01-01 The invention relates to the selective and sequential reduction of halodisilanes by reacting these compounds at room temperature or below with trialkyltin hydrides or dialkyltin dihydrides without the use of free radical intermediates. The alkyltin hydrides selectively and sequentially reduce the Si-Cl, Si-Br or Si-I bonds while leaving intact the Si-Si and Si-F bonds present. 5. Method of Preventing Shrinkage of Aluminum Foam Using Carbonates Directory of Open Access Journals (Sweden) Takashi Nakamura 2011-12-01 Full Text Available Metallic foams are commonly produced using titanium hydride as a foaming agent. Carbonates produce aluminum foam with a fine and homogenous cell structure. However, foams produced using carbonates show marked shrinkage, which is clearly different from those produced using titanium hydride. It is essential for practical applications to clarify foam shrinkage and establish a method of preventing it. In this research, cell structures were observed to study the shrinkage of aluminum foam produced using carbonates. The cells of foam produced using dolomite as a foaming agent connected to each other with maximum expansion. It was estimated that foaming gas was released through connected cells to the outside. It was assumed that cell formation at different sites is effective in preventing shrinkage induced by cell connection. The multiple additions of dolomite and magnesium carbonate, which have different decomposition temperatures, were applied. The foam in the case with multiple additions maintained a density of 0.66 up to 973 K, at which the foam produced using dolomite shrank. It was verified that the multiple additions of carbonates are effective in preventing shrinkage. 6. 金属铝固液气完全物态方程研究%A solid-liquid-gas three-phase complete equation of state of aluminum Institute of Scientific and Technical Information of China (English) 于继东; 李平; 王文强; 吴强 2014-01-01 Based on the GRAY equation of state (EOS), we establish a solid-liquid-gas three-phase complete EOS, and compare it with the experimental isothermal compression data, Hugoniot data, melting data and thermodynamic functions under ambient pressure. It is indicated that the EOS in this paper can describe reasonably the thermodynamic state of aluminum in a wide region.%基于GRAY模型建立了金属铝的固液气三相完全物态方程，并与等温压缩线、Hugoniot线、熔化线以及零压热力学函数的实验结果进行对比，表明本物态方程可合理描述金属铝在宽广热力学空间的热力学状态。 7. Novel fuel cell stack with coupled metal hydride containers Science.gov (United States) Liu, Zhixiang; Li, Yan; Bu, Qingyuan; Guzy, Christopher J.; Li, Qi; Chen, Weirong; Wang, Cheng 2016-10-01 Air-cooled, self-humidifying hydrogen fuel cells are often used for backup and portable power sources, with a metal hydride used as the hydrogen storage material. To provide a stable hydrogen flow to the fuel cell stack, heat must be provided to the metal hydride. Conventionally, the heat released from the exothermic reaction of hydrogen and oxygen in the fuel cell stack to the exhaust air is used to heat a separate metal hydride container. In this case, the heat is only partially used instead of being more closely coupled because of the heat transfer resistances in the system. To achieve better heat integration, a novel scheme is proposed whereby hydrogen storage and single fuel cells are more closely coupled. Based on this idea, metal hydride containers in the form of cooling plates were assembled between each pair of cells in the stack so that the heat could be directly transferred to a metal hydride container of much larger surface-to-volume ratio than conventional separate containers. A heat coupled fuel cell portable power source with 10 cells and 11 metal hydride containers was constructed and the experimental results show that this scheme is beneficial for the heat management of fuel cell stack. 8. Optimization of Hydride Rim Formation in Unirradiated Zr 4 Cladding Energy Technology Data Exchange (ETDEWEB) Shimskey, Rick W.; Hanson, Brady D.; MacFarlan, Paul J. 2013-09-30 The purpose of this work is to build on the results reported in the M2 milestone M2FT 13PN0805051, document number FCRD-USED-2013-000151 (Hanson, 2013). In that work, it was demonstrated that unirradiated samples of zircaloy-4 cladding could be pre-hydrided at temperatures below 400°C in pure hydrogen gas and that the growth of hydrides on the surface could be controlled by changing the surface condition of the samples and form a desired hydride rim on the outside diameter of the cladding. The work performed at Pacific Northwest National Laboratory since the issuing of the M2 milestone has focused its efforts to optimize the formation of a hydride rim on available zircaloy-4 cladding samples by controlling temperature variation and gas flow control during pre-hydriding treatments. Surface conditioning of the outside surface was also examined as a variable. The results of test indicate that much of the variability in the hydride thickness is due to temperature variation occurring in the furnaces as well as how hydrogen gas flows across the sample surface. Efforts to examine other alloys, gas concentrations, and different surface conditioning plan to be pursed in the next FY as more cladding samples become available 9. Effect of niobium additions on initial hydriding kinetics of uranium Energy Technology Data Exchange (ETDEWEB) Li, Ruiwen, E-mail: ruiwenli@163.com; Wang, Xiaolin 2014-06-01 To study the behavior of hydrogen corrosion at the surface of U, U–2.5 wt%Nb alloy and U–5.7 wt%Nb, a gas–solid reaction system with an in situ microscope was designed. The nucleation and growth of the hydride of the alloy were continuously observed and recorded by a computer. The different characteristics of the hydrides on U metal and U–2.5 wt%Nb showed that the later alloy is more susceptible to hydrogen corrosion than the former. The growth rate of hydride of U–2.5 wt%Nb, calculated by measuring the perimeter of the hydride spots recorded by the in situ microscope, exhibited a reaction temperature dependency in the range of 40–160 °C, for pressure of 0.8 × 10{sup 5} Pa. An Arrhenius plot for growth rate versus temperature yielded activation energy of 24.34 kJ/mol for the hydriding of U–2.5 wt%Nb alloy. The maximum hydriding rate was obtained at 125 °C, whose thermodynamics reason was discussed. 10. Microbial corrosion of aluminum alloy. Science.gov (United States) Yang, S S; Chen, C Y; Wei, C B; Lin, Y T 1996-11-01 Several microbes were isolated from the contaminated fuel-oil in Taiwan and the microbial corrosion of aluminum alloy A356-T6 was tested by MIL-STD-810E test method. Penicillium sp. AM-F5 and Cladosporium resinac ATCC 22712 had significant adsorption and pitting on the surface of aluminum alloy, Pseudomonas acruginosa AM-B5 had weak adsorption and some precipitation in the bottom, and Candida sp. AM-Y1 had the less adsorption and few cavities formation on the surface. pH of the aqueous phase decreased 0.3 to 0.7 unit for 4 months of incubation. The corrosion of aluminum alloy was very significant in the cultures of Penicillium sp. AM-F2, Penicillium sp. AM-F5 and C. resinac ATCC 22712. The major metabolites in the aqueous phase with the inoculation of C. resinac were citric acid and oxalic acid, while succinic acid and fumaric acid were the minors. PMID:10592801 11. Aluminum plasmonic multicolor meta-hologram. Science.gov (United States) Huang, Yao-Wei; Chen, Wei Ting; Tsai, Wei-Yi; Wu, Pin Chieh; Wang, Chih-Ming; Sun, Greg; Tsai, Din Ping 2015-05-13 We report a phase-modulated multicolor meta-hologram (MCMH) that is polarization-dependent and capable of producing images in three primary colors. The MCMH structure is made of aluminum nanorods that are arranged in a two-dimensional array of pixels with surface plasmon resonances in red, green, and blue. The aluminum nanorod array is patterned on a 30 nm thick SiO2 spacer layer sputtered on top of a 130 nm thick aluminum mirror. With proper design of the structure, we obtain resonances of narrow bandwidths to allow for implementation of the multicolor scheme. Taking into account of the wavelength dependence of the diffraction angle, we can project images to specific locations with predetermined size and order. With tuning of aluminum nanorod size, we demonstrate that the image color can be continuously varied across the visible spectrum. 12. INFLUENCE OF TEMPERATURE AND PRESSURE ON THE KINETICS OF Mg-6mol%LaNi PREPARED BY HYDRIDING COMBUSTION SYNTHESIS Institute of Scientific and Technical Information of China (English) Q. Li; K.C. Chou; K.D. Xu; L.J. Jiang; J.Y. Zhang; X.G. Lu 2006-01-01 A new model to study the hydriding/dehydriding (H/D) kinetic mechanism has been applied in the two-phase (α-β) region of the Mg-6mol%LaNi composite at temperature and pressure ranging from 523 to 623K and 0.256 to 0.992MPa H2, respectively. The coincidence of the theoretical calculation with the experimental data indicates that the rate-limiting step is hydrogen diffusion in the β phase for hydriding process and the diffusion of hydrogen in the α solid solution for hydrogen desorption with activation energies 89500 and 87900J/mol H2 for H/D processes, respectively, which were much smaller than those of MgH2 and can be attributed to the La and Ni additions. 13. Nitrogen hydrides in the cold envelope of IRAS16293-2422 OpenAIRE Hily-Blant, Pierre; Maret, Sébastien; Bacmann, A.; Bottinelli, Sandrine; Parise, Bérengère; Caux, Emmanuel; Faure, Alexandre 2010-01-01 Nitrogen is the fifth most abundant element in the Universe, yet the gas-phase chemistry of N-bearing species remains poorly understood. Nitrogen hydrides are key molecules of nitrogen chemistry. Their abundance ratios place strong constraints on the production pathways and reaction rates of nitrogen-bearing molecules. We observed the class 0 protostar IRAS16293-2422 with the heterodyne instrument HIFI, covering most of the frequency range from 0.48 to 1.78~THz at high spectral resolution. Th... 14. Aspects of aluminum toxicity Energy Technology Data Exchange (ETDEWEB) Hewitt, C.D.; Savory, J.; Wills, M.R. (Univ. of Virginia Health Sciences Center, Charlottesville (USA)) 1990-06-01 Aluminum is the most abundant metal in the earth's crust. The widespread occurrence of aluminum, both in the environment and in foodstuffs, makes it virtually impossible for man to avoid exposure to this metal ion. Attention was first drawn to the potential role of aluminum as a toxic metal over 50 years ago, but was dismissed as a toxic agent as recently as 15 years ago. The accumulation of aluminum, in some patients with chronic renal failure, is associated with the development of toxic phenomena; dialysis encephalopathy, osteomalacic dialysis osteodystrophy, and an anemia. Aluminum accumulation also occurs in patients who are not on dialysis, predominantly infants and children with immature or impaired renal function. Aluminum has also been implicated as a toxic agent in the etiology of Alzheimer's disease, Guamiam amyotrophic lateral sclerosis, and parkinsonism-dementia. 119 references. 15. A study on the antiferromagnetic behavior of the hydride CeRuGeH adopting the ZrCuSiAs-type structure Energy Technology Data Exchange (ETDEWEB) Chevalier, B; Gaudin, E [CNRS, Universite de Bordeaux, ICMCB, 87 Avenue du Docteur Albert Schweitzer, 33608 Pessac Cedex (France); Geibel, C; Canales, N C [Max Planck Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, 01187 Dresden (Germany); Hermes, W; Poettgen, R, E-mail: chevalie@icmcb-bordeaux.cnrs.f [Institut fuer Anorganische und Analytische Chemie, Corrensstrasse 30, Westfaelische Wilhelms Universitaet Muenster, 48149 Muenster (Germany) 2010-02-03 The non-magnetic heavy fermion behavior of CeRuGe is destroyed by hydrogen insertion. The resulting hydride CeRuGeH, investigated by magnetization, thermoelectric, electrical resistivity and specific heat measurements, exhibits an antiferromagnetic ordering below T{sub N} = 4.0(2) K weakly influenced by the Kondo effect. Below T{sub N}, a metamagnetic double transition induced by an applied magnetic field was evidenced for CeRuGeH. This hydride presents a simple field-temperature phase diagram in comparison to that determined for the equivalent compound CeRuSiH. 16. Effect of lanthanum hydride on microstructures and hydrogen storage performances of 2LiNH2-MgH2 system Institute of Scientific and Technical Information of China (English) 朱惜林; 韩树民; 赵鑫; 李媛; 刘宝忠 2014-01-01 Hydrogen storage properties of 2LiNH2-MgH2 system were improved by adding lanthanum hydride (LaH3), and the role of LaH3 in hydrogen sorption process of Li-Mg-N-H system was investigated. Temperature programmed sorption results showed that the addition of lanthanum hydride reduced the dehydriding/hydriding onset temperature of 2LiNH2-MgH2 system by at least 15 K. Moreover, A 0.053 wt.%/min average rate was determined for the hydrogen desorption of 2LiNH2-MgH2-0.05LaH3 composite, while it was only 0.035 wt.%/min for 2LiNH2-MgH2 system. Hydrogen absorption capacity increased from 1.62 wt.% to 2.12 wt.% within 200 min by adding LaH3 into 2LiNH2-MgH2 system at 383 K. In the dehydrogenation of 2LiNH2-MgH2-0.05LaH3 composite, LaH2 transferred to LaN phase, which reversed to LaH2 in the following hydrogen adsorption process. The reversible reaction of LaH2 ef-fectively promoted the hydrogen sorption of Li-Mg-N-H system. Moreover, the homogenous distribution of fine La hydride was fa-vorable to improving effect of lanthanum hydride. 17. Synthesis and properties of the Mg{sub 2}Ni{sub 0.5}Co{sub 0.5}H{sub 4.4} hydride Energy Technology Data Exchange (ETDEWEB) Verbovytskyy, Yu. [Physico-Mechanical Institute, NAS of Ukraine, 5 Naukova str., 79601 Lviv (Ukraine); Zhang, J.; Cuevas, F.; Paul-Boncour, V. [Institut de Chimie et des Materiaux de Paris Est, CMTR, UMR 7182, CNRS-UPEC, 2-8 rue H. Dunant, 94320 Thiais (France); Zavaliy, I., E-mail: zavaliy@ipm.lviv.ua [Physico-Mechanical Institute, NAS of Ukraine, 5 Naukova str., 79601 Lviv (Ukraine) 2015-10-05 Graphical abstract: Crystal structure of the Mg{sub 2}Ni{sub 0.5}Co{sub 0.5}H{sub 4.4} hydride. - Highlights: • Preparation of the Mg{sub 2}Ni{sub 0.5}Co{sub 0.5}H{sub 4.4} hydride by reactive ball milling. • Crystal structure determination by X-ray powder diffraction. • Electrochemical studies of the ball milled MH/Ni electrodes. - Abstract: The Mg{sub 2}Ni{sub 0.5}Co{sub 0.5}H{sub 4.4} hydride with a grain size of 16 nm was prepared by reactive ball milling. Its crystal structure was studied by X-ray powder diffraction. A tetragonal Mg{sub 2}CoH{sub 5} structure type was suggested for the obtained hydride. The decomposition temperature of the Mg{sub 2}Ni{sub 0.5}Co{sub 0.5}H{sub 4.4} phase was observed at 213 °C. Electrochemical measurements as negative electrode of Ni–MH battery were also performed. Significant improvements can be made by ball-milling the hydride with nickel powder. 18. Chemical Hydride Slurry for Hydrogen Production and Storage Energy Technology Data Exchange (ETDEWEB) McClaine, Andrew W 2008-09-30 The purpose of this project was to investigate and evaluate the attractiveness of using a magnesium chemical hydride slurry as a hydrogen storage, delivery, and production medium for automobiles. To fully evaluate the potential for magnesium hydride slurry to act as a carrier of hydrogen, potential slurry compositions, potential hydrogen release techniques, and the processes (and their costs) that will be used to recycle the byproducts back to a high hydrogen content slurry were evaluated. A 75% MgH2 slurry was demonstrated, which was just short of the 76% goal. This slurry is pumpable and storable for months at a time at room temperature and pressure conditions and it has the consistency of paint. Two techniques were demonstrated for reacting the slurry with water to release hydrogen. The first technique was a continuous mixing process that was tested for several hours at a time and demonstrated operation without external heat addition. Further work will be required to reduce this design to a reliable, robust system. The second technique was a semi-continuous process. It was demonstrated on a 2 kWh scale. This system operated continuously and reliably for hours at a time, including starts and stops. This process could be readily reduced to practice for commercial applications. The processes and costs associated with recycling the byproducts of the water/slurry reaction were also evaluated. This included recovering and recycling the oils of the slurry, reforming the magnesium hydroxide and magnesium oxide byproduct to magnesium metal, hydriding the magnesium metal with hydrogen to form magnesium hydride, and preparing the slurry. We found that the SOM process, under development by Boston University, offers the lowest cost alternative for producing and recycling the slurry. Using the H2A framework, a total cost of production, delivery, and distribution of4.50/kg of hydrogen delivered or $4.50/gge was determined. Experiments performed at Boston 19. Study on Kinetics of Hydrogen Absorption by Metal Hydride Slurries Ⅰ. Absorption of Hydrogen by Hydrogen Storage Alloy MlNi5 Suspended in Benzene Institute of Scientific and Technical Information of China (English) 安越; 陈长聘; 徐国华; 蔡官明; 王启东 2002-01-01 The absorption of hydrogen was studied in metal hydride slurry, which is formed by benzene and hydrogen storage alloy powder. The influence of temperature on the rate of absorption was discussed using three-phase mass transfer model. It is also concluded that the suitable absorption temperature is 313 K. 20. Simultaneous Heat and Mass Transfer in DU Hydriding International Nuclear Information System (INIS) The sources of nuclear fusion reaction are deuterium (D) and tritium (T). Generally, D is fused into T, which generates helium atoms and neutrons. At this time, a tremendous amount of energy is generated. D + T → 4He + n (E = 17.6 MeV) Hydrogen is a gas, and cannot be stored in large amounts. In addition, it can be explosive. Therefore, one of the storing methods for hydrogen is metal hydride. In this research, several kinds of metal hydrides including U, Zr, ZrCo, ZrNi, and LaNi5 have been simulated through modeling work of hydrogen absorption, desorption, and pressure effect in a bed using DU. For the exact modeling of the hydriding process, it is necessary to calculate simultaneous heat and mass transfer because, in the hydriding process, not only is hydrogen gas transported by mass transport and chemisorption but heat transfer also occurs through absorption. Therefore, in this paper, we tried to calculate the simultaneous heat and mass transfer using numerical analysis methods. Simultaneous heat and mass transfer in DU hydriding is well fitted compared to the experimental data, and is more reasonable considering only one variable. The hydriding process changes the temperature and atomic ratio simultaneously, and thus it is necessary to consider in company with two transport phenomena. The numerical analysis method applied Euler's method; however, the Runge-Kutta method is a more widely used numerical solution of a differential equation. Therefore, when analyzing the hydriding process, Runge-Kutta or another method will henceforth be applied 1. The aluminum chemistry and corrosion in alkaline solutions Energy Technology Data Exchange (ETDEWEB) Zhang Jinsuo [International Nuclear System Engineering, MS-K 575, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)], E-mail: jszhang@lanl.gov; Klasky, Marc; Letellier, Bruce C. [International Nuclear System Engineering, MS-K 575, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States) 2009-02-15 Aluminum-alkaline solution systems are very common in engineering applications including nuclear engineering. Consequently, a thorough knowledge of the chemistry of aluminum and susceptibility to corrosion in alkaline solutions is reviewed. The aluminum corrosion mechanism and corrosion rate are examined based on current experimental data. A review of the phase transitions with aging time and change of environment is also performed. Particular attention is given to effect of organic and inorganic ions. As an example, the effect of boron is examined in detail because of the application in nuclear reactor power systems. Methods on how to reduce the corrosion rate of aluminum in alkaline solutions are also highlighted. 2. Joining of parts via magnetic heating of metal aluminum powders Science.gov (United States) Baker, Ian 2013-05-21 A method of joining at least two parts includes steps of dispersing a joining material comprising a multi-phase magnetic metal-aluminum powder at an interface between the at least two parts to be joined and applying an alternating magnetic field (AMF). The AMF has a magnetic field strength and frequency suitable for inducing magnetic hysteresis losses in the metal-aluminum powder and is applied for a period that raises temperature of the metal-aluminum powder to an exothermic transformation temperature. At the exothermic transformation temperature, the metal-aluminum powder melts and resolidifies as a metal aluminide solid having a non-magnetic configuration. 3. Aluminum-stabilized Nb/sub 3/Sn superconductor Science.gov (United States) Scanlan, R.M. 1984-02-10 This patent discloses an aluminum-stabilized Nb/sub 3/Sn superconductor and process for producing same, utilizing ultrapure aluminum. Ductile components are co-drawn with aluminum to produce a conductor suitable for winding magnets. After winding, the conductor is heated to convert it to the brittle Nb/sub 3/Sn superconductor phase, using a temperature high enough to perform the transformation but still below the melting point of the aluminum. This results in reaction of substantially all of the niobium, while providing stabilization and react-in-place features which are beneficial in the fabrication of magnets utilizing superconducting materials. 4. Aluminum-stabilized Nb[sub 3]Sn superconductor Science.gov (United States) Scanlan, R.M. 1988-05-10 Disclosed are an aluminum-stabilized Nb[sub 3]Sn superconductor and process for producing same, utilizing ultrapure aluminum. Ductile components are co-drawn with aluminum to produce a conductor suitable for winding magnets. After winding, the conductor is heated to convert it to the brittle Nb[sub 3]Sn superconductor phase, using a temperature high enough to perform the transformation but still below the melting point of the aluminum. This results in reaction of substantially all of the niobium, while providing stabilization and react-in-place features which are beneficial in the fabrication of magnets utilizing superconducting materials. 4 figs. 5. Reactions of NO with nitrogen hydrides x Science.gov (United States) Mebel, A. M.; Lin, M. C. In this review, we consider the reactions of NO ( x 1,2) with the nitrogen x hydrides NH, NH and NH . The reactions are relevant to the post-combustion, non-catalytic reduction of NO with NH in the thermal de-NO process and with x x HNCO in the rapid reduction of NO as well as to the thermal decomposition of x some high-energy materials, including ammonium dinitramide. The practical importance has motivated considerable theoretical interest in these reactions. We review numerous ab - initio molecular orbital studies of potential energy surfaces for NO NH and theoretical calculations of their kinetic parameters, such as x y thermal rate constants and branching ratios of various products. The most advanced theoretical calculations are carried out using the Gaussian-2 family of methods which provides the chemical accuracy (within 2 kcal mol ) for the energetics and molecular parameters of the reactants, products, intermediates and transition states. We present a detailed comparison of the theoretical results with available experimental data. We show that the reactions of NO with NH and NH x are very fast because they occur without a barrier and lead to the formation of multiple products which include radicals and stable molecules. The reactions of NO with NH , taking place by the H abstraction to form NH and HNO , are slow x x but still relevant to the NH de-NO system, because of their fast reverse processes x which have not yet been measured experimentally. 6. Is the Aluminum Hypothesis Dead? OpenAIRE Lidsky, Theodore I. 2014-01-01 The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed w... 7. High energy density aluminum battery Energy Technology Data Exchange (ETDEWEB) Brown, Gilbert M.; Paranthaman, Mariappan Parans; Dai, Sheng; Dudney, Nancy J.; Manthiram, Arumugan; McIntyre, Timothy J.; Sun, Xiao-Guang; Liu, Hansan 2016-10-11 Compositions and methods of making are provided for a high energy density aluminum battery. The battery comprises an anode comprising aluminum metal. The battery further comprises a cathode comprising a material capable of intercalating aluminum or lithium ions during a discharge cycle and deintercalating the aluminum or lithium ions during a charge cycle. The battery further comprises an electrolyte capable of supporting reversible deposition and stripping of aluminum at the anode, and reversible intercalation and deintercalation of aluminum or lithium at the cathode. 8. Effect of metallic phase species on the corrosion resistance of M/(10NiO-NiFe2O4) cermet inert anode of aluminum electrolysis Institute of Scientific and Technical Information of China (English) 2006-01-01 NiFe2O4-based cermet inert anodes with metallic phase compositions of Cu, Ni and 85Cu15Ni were prepared by cold pressing-sintering. Their corrosion resistance was also investigated in Na3 AlF6-Al2 O3 melts. The results show that the metallic phase species in cermets have no effect on the concentration of impurities in bath during electrolysis, the total steady-state concentration of impurities is almost the same, I.e. Between 4.12 × 10-4- 4.80 × 10-4. There exists metal preferential corrosion for the cermet inert anode with metal Ni as metallic phase. For NiFe2 O4-based cermets, the cermet with metal Cu as metallic phase exhibits better corrosion resistance than the others. 9. Effect of metallic phase content on mechanical properties of (85Cu- 15Ni)/(10NiO-NiFe2O4) cermet inert anode for aluminum electrolysis Institute of Scientific and Technical Information of China (English) 2007-01-01 (85Cu-15Ni)/(10NiO-NiFe2O4) cermets were prepared with Cu-Ni mixed powders as toughening metallic phase and 10NiO-NiFe2O4 as ceramic matrix. The phase composition, microstructure of composite and the effect of metallic phase content on bending strength, hardness, fracture toughness and thermal shock resistance were studied. X-ray diffraction analysis indicates the coexistence of (Cu-Ni), NiO and NiFe2O4 phases in the cermets. Within the content range of metallic phase from 0% to 20% (mass fraction), the maximal bending strength (176.4 MPa) and the minimal porosity (3.9%) of composite appear at the metallic phase content of 5%. The fracture toughness increases and Vickers' hardness decreases with increasing metal content. When the thermal shock temperature difference (△t) is below 200 ℃, the loss rate of residual strength for 10NiO-NiFe2O4 ceramic is only 8%, but about 40% for (85Cu-15Ni)/(10NiO-NiFe2O4) cermets. As △t is above 200 ℃, the residual strength sharply decreases for sample CN0 and falls slowly for samples CN5-CN20. 10. Lithium-aluminum-magnesium electrode composition Science.gov (United States) Melendres, Carlos A.; Siegel, Stanley 1978-01-01 A negative electrode composition is presented for use in a secondary, high-temperature electrochemical cell. The cell also includes a molten salt electrolyte of alkali metal halides or alkaline earth metal halides and a positive electrode including a chalcogen or a metal chalcogenide as the active electrode material. The negative electrode composition includes up to 50 atom percent lithium as the active electrode constituent and a magnesium-aluminum alloy as a structural matrix. Various binary and ternary intermetallic phases of lithium, magnesium, and aluminum are formed but the electrode composition in both its charged and discharged state remains substantially free of the alpha lithium-aluminum phase and exhibits good structural integrity. 11. Numerical simulation and performance test of metal hydride hydrogen storage system Directory of Open Access Journals (Sweden) Tzu-Hsiang Yen, Bin-Hao Chen, Bao-Dong Chen 2011-05-01 Full Text Available Metal hydride reactors are widely used in many industrial applications, such as hydrogen storage, thermal compression, heat pump, etc. According to the research requirement of metal hydride hydrogen storage, the thermal analyses have been implemented in the paper. The metal hydride reaction beds are considered as coupled cylindrical tube modules which combine the chemical absorption and desorption in metal hydride. The model is then used metal hydride LaNi5 as an example to predict the performance of metal hydride hydrogen storage devices, such as the position of hydration front and the thermal flux. Under the different boundary condition the characteristics of heat transfer and mass transfer in metal hydride have influence on the hydrogen absorption and desorption. The researches revealed that the scroll design can improve the temperature distribution in the reactor and the porous tube for directing hydrogen can increase the penetration depth of hydride reaction to decrease the hydrogen absorption time. 12. The aluminum smelting process. Science.gov (United States) Kvande, Halvor 2014-05-01 This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development. 13. Sodium-based hydrides for thermal energy applications Science.gov (United States) Sheppard, D. A.; Humphries, T. D.; Buckley, C. E. 2016-04-01 Concentrating solar-thermal power (CSP) with thermal energy storage (TES) represents an attractive alternative to conventional fossil fuels for base-load power generation. Sodium alanate (NaAlH4) is a well-known sodium-based complex metal hydride but, more recently, high-temperature sodium-based complex metal hydrides have been considered for TES. This review considers the current state of the art for NaH, NaMgH3- x F x , Na-based transition metal hydrides, NaBH4 and Na3AlH6 for TES and heat pumping applications. These metal hydrides have a number of advantages over other classes of heat storage materials such as high thermal energy storage capacity, low volume, relatively low cost and a wide range of operating temperatures (100 °C to more than 650 °C). Potential safety issues associated with the use of high-temperature sodium-based hydrides are also addressed. 14. Two-Dimensional Boron Hydride Sheets: High Stability, Massless Dirac Fermions, and Excellent Mechanical Properties. Science.gov (United States) Jiao, Yalong; Ma, Fengxian; Bell, John; Bilic, Ante; Du, Aijun 2016-08-22 Two-dimensional (2D) boron sheets have been successfully synthesized in recent experiments, however, some important issues remain, including the dynamical instability, high energy, and the active surface of the sheets. In an attempt to stabilize 2D boron layers, we have used density functional theory and global minimum search with the particle-swarm optimization method to predict four stable 2D boron hydride layers, namely the C2/m, Pbcm, Cmmm, and Pmmn sheets. The vibrational normal mode calculations reveal all these structures are dynamically stable, indicating potential for successful experimental synthesis. The calculated Young's modulus indicates a high mechanical strength for the C2/m and Pbcm phases. Most importantly, the C2/m, Pbcm, and Pmmn structures exhibit Dirac cones with massless Dirac fermions and the Fermi velocities for the Pbcm and Cmmm structures are even higher than that of graphene. The Cmmm phase is reported as the first discovery of Dirac ring material among boron-based 2D structures. The unique electronic structure of the 2D boron hydride sheets makes them ideal for nanoelectronics applications. PMID:27460282 15. High-Spin Cobalt Hydrides for Catalysis Energy Technology Data Exchange (ETDEWEB) Holland, Patrick L. [Yale University 2013-08-29 Organometallic chemists have traditionally used catalysts with strong-field ligands that give low-spin complexes. However, complexes with a weak ligand field have weaker bonds and lower barriers to geometric changes, suggesting that they may lead to more rapid catalytic reactions. Developing our understanding of high-spin complexes requires the use of a broader range of spectroscopic techniques, but has the promise of changing the mechanism and/or selectivity of known catalytic reactions. These changes may enable the more efficient utilization of chemical resources. A special advantage of cobalt and iron catalysts is that the metals are more abundant and cheaper than those currently used for major industrial processes that convert unsaturated organic molecules and biofeedstocks into useful chemicals. This project specifically evaluated the potential of high-spin cobalt complexes for small-molecule reactions for bond rearrangement and cleavage reactions relevant to hydrocarbon transformations. We have learned that many of these reactions proceed through crossing to different spin states: for example, high-spin complexes can flip one electron spin to access a lower-energy reaction pathway for beta-hydride elimination. This reaction enables new, selective olefin isomerization catalysis. The high-spin cobalt complexes also cleave the C-O bond of CO2 and the C-F bonds of fluoroarenes. In each case, the detailed mechanism of the reaction has been determined. Importantly, we have discovered that the cobalt catalysts described here give distinctive selectivities that are better than known catalysts. These selectivities come from a synergy between supporting ligand design and electronic control of the spin-state crossing in the reactions. 16. Iron Hydride Detection and Intramolecular Hydride Transfer in a Synthetic Model of Mono-Iron Hydrogenase with a CNS Chelate. Science.gov (United States) Durgaprasad, Gummadi; Xie, Zhu-Lin; Rose, Michael J 2016-01-19 We report the identification and reactivity of an iron hydride species in a synthetic model complex of monoiron hydrogenase. The hydride complex is derived from a phosphine-free CNS chelate that includes a Fe-C(NH)(═O) bond (carbamoyl) as a mimic of the active site iron acyl. The reaction of [((O═)C(HN)N(py)S(Me))Fe(CO)2(Br)] (1) with NaHBEt3 generates the iron hydride intermediate [((O═)C(HN)N(py)S(Me))Fe(H)(CO)2] (2; δFe-H = -5.08 ppm). Above -40 °C, the hydride species extrudes CH3S(-) via intramolecular hydride transfer, which is stoichiometrically trapped in the structurally characterized dimer μ2-(CH3S)2-[((O═)C(HN)N(Ph))Fe(CO)2]2 (3). Alternately, when activated by base ((t)BuOK), 1 undergoes desulfurization to form a cyclometalated species, [((O═)C(NH)NC(Ph))Fe(CO)2] (5); derivatization of 5 with PPh3 affords the structurally characterized species [((O═)C(NH)NC)Fe(CO)(PPh3)2] (6), indicating complex 6 as the common intermediate along each pathway of desulfurization. 17. A new heat storage system using metal hydrides Science.gov (United States) Ono, S.; Kawamura, M.; Ishido, Y.; Akiba, E.; Higano, S. The development of a prototype chemical heat storage system, designed for the accumulation of fairly high temperature (300 - 400 C) waste heat, and called the Hydriding Heat Storage system is presented. Mg2Ni hydride is used as the high temperature heat storing medium, and LaNi5H6 is used as a reservoir for the hydrogen released from the heat storing medium. The system has been in development since 1976, and a 2000 kcal heat capacity prototype system is to be completed by 1982. Basic investigations, i.e., reaction kinetics of absorption and desorption, and heat transfer characteristics of the hydride and/or the metal powder packed bed, are described. 18. Kinetic and structural aspects of tantalum hydride formation Directory of Open Access Journals (Sweden) R. DIMITRIJEVIC 2003-09-01 Full Text Available Tantalum hydrides of various composition were synthesized by equilibrating tantalum with hydrogen at six different temperatures from 573 to 823 K, under a constant hydrogen pressure of 1 bar. Both the exact Ta/H mole ratios and the kinetic parameters of hydriding were determined on the basis of the dependence of the H/Ta mole ratio on time. The influence of stoichiometry on the appearance of X-ray powder diffractograms at room temperature was studied. As a consequence of hydriding, for ratios H/Ta > 0.2, the original bcc Ta-lattice undergoes distortion, manifesting itself as both a shift and a splitting of the X-ray patterns in the X-ray diffractograms. For samples with H/Ta < 0.2, the appearance of some superstructure reflections at low Bragg angles was noted, which suggests a long range ordering of hydrogen with orthorhombic symmetry. 19. Theoretical Estimate of Hydride Affinities of Aromatic Carbonyl Compounds Institute of Scientific and Technical Information of China (English) AI Teng; ZHU Xiao-Qing; CHENG Jin-Pei 2003-01-01 @@ Aromatic carbonyl compounds are one type of the most important organic compounds, and the reductions ofthem by hydride agents such as LiAlH4 or NaBH4 are widely used in organic synthesis. The reactivity of carbonyl compounds generally increases in the following order: ketone ＜ aldehyde, and amide ＜ acid ＜ ester ＜ acid halide, which could be related to their hydride affinities (HA). In the previous paper, Robert[1] calculated the absolute HAof a series of small non-aromatic carbonyl compounds. In this paper, we use DFT method at B3LYP/6-311 + + G (2d, 2p)∥B3LYP/6-31 + G* level to estimate hydride affinities of five groups of aromatic carbonyl compounds. The detailed results are listed in Table 1. 20. Higher Strength, Lighter Weight Aluminum Spacecraft Structures Project Data.gov (United States) National Aeronautics and Space Administration — This SBIR Phase I program proposes to develop a bulk processing technology for producing ultra fine grain (UFG) aluminum alloy structures. The goal is to... 1. Clinical biochemistry of aluminum Energy Technology Data Exchange (ETDEWEB) King, S.W.; Savory, J.; Wills, M.R. 1981-05-01 Aluminum toxicity has been implicated in the pathogenesis of a number of clinical disorders in patients with chronic renal failure on long-term intermittent hemodialysis treatment. The predominant disorders have been those involving either bone (osteomalacic dialysis osteodystrophy) or brain (dialysis encephalopathy). In nonuremic patients, an increased brain aluminum concentration has been implicated as a neurotoxic agent in the pathogenesis of Alzheimer's disease and was associated with experimental neurofibrillary degeneration in animals. The brain aluminum concentrations of patients dying with the syndrome of dialysis encephalopathy (dialysis dementia) are significantly higher than in dialyzed patients without the syndrome and in nondialyzed patients. Two potential sources for the increased tissue content of aluminum in patients on hemodialysis have been proposed: (1) intestinal absorption from aluminum containing phosphate-binding gels, and (2) transfer across the dialysis membrane from aluminum in the water used to prepare the dialysate. These findings, coupled with our everyday exposure to the ubiquitous occurrence of aluminum in nature, have created concerns over the potential toxicity of this metal. 2. Advances in aluminum pretreatment Energy Technology Data Exchange (ETDEWEB) Sudour, Michel; Maintier, Philippe [PPG Industries France, 3 Z.A.E. Les Dix Muids, B.P. 89, F-59583 Marly (France); Simpson, Mark [PPG Industries Inc., 1200 Piedmont Troy, Michigan 48083 (United States); Quaglia, Paolo [PPG Industries Italia, Via Garavelli 21, I-15028 Quattordio (Italy) 2004-07-01 As automotive manufacturers continue to look for ways to reduce vehicle weight, aluminum is finding more utility as a body panel component. The substitution of cold-rolled steel and zinc-coated substrates with aluminum has led to new challenges in vehicle pretreatment. As a result, changes to traditional pretreatment chemistries and operating practices are necessary in order to produce an acceptable coating on aluminum body panels. These changes result in increased sludging and other undesirable characteristics. In addition to the chemistry changes, there are also process-related problems to consider. Many existing automotive pretreatment lines simply were not designed to handle aluminum and its increased demands on filtration and circulation equipment. To retrofit such a system is capital intensive and in addition to requiring a significant amount of downtime, may not be totally effective. Thus, the complexities of pre-treating aluminum body panels have actually had a negative effect on efforts to introduce more aluminum into new vehicle design programs. Recent research into ways of reducing the negative effects has led to a new understanding of the nature of zinc phosphate bath -aluminum interactions. Many of the issues associated with the pretreatment of aluminum have been identified and can be mitigated with only minor changes to the zinc phosphate bath chemistry. The use of low levels of soluble Fe ions, together with free fluoride, has been shown to dramatically improve the efficiency of a zinc phosphate system processing aluminum. Appearance of zinc phosphate coatings, coating weights and sludge are all benefited by this chemistry change. (authors) 3. Thermodynamic integration based on classical atomistic simulations to determine the Gibbs energy of condensed phases: Calculation of the aluminum-zirconium system Science.gov (United States) Harvey, J.-P.; Gheribi, A. E.; Chartrand, P. 2012-12-01 In this work, an in silico procedure to generate a fully coherent set of thermodynamic properties obtained from classical molecular dynamics (MD) and Monte Carlo (MC) simulations is proposed. The procedure is applied to the Al-Zr system because of its importance in the development of high strength Al-Li alloys and of bulk metallic glasses. Cohesive energies of the studied condensed phases of the Al-Zr system (the liquid phase, the fcc solid solution, and various orthorhombic stoichiometric compounds) are calculated using the modified embedded atom model (MEAM) in the second-nearest-neighbor formalism (2NN). The Al-Zr MEAM-2NN potential is parameterized in this work using ab initio and experimental data found in the literature for the AlZr3-L12 structure, while its predictive ability is confirmed for several other solid structures and for the liquid phase. The thermodynamic integration (TI) method is implemented in a general MC algorithm in order to evaluate the absolute Gibbs energy of the liquid and the fcc solutions. The entropy of mixing calculated from the TI method, combined to the enthalpy of mixing and the heat capacity data generated from MD/MC simulations performed in the isobaric-isothermal/canonical (NPT/NVT) ensembles are used to parameterize the Gibbs energy function of all the condensed phases in the Al-rich side of the Al-Zr system in a CALculation of PHAse Diagrams (CALPHAD) approach. The modified quasichemical model in the pair approximation (MQMPA) and the cluster variation method (CVM) in the tetrahedron approximation are used to define the Gibbs energy of the liquid and the fcc solid solution respectively for their entire range of composition. Thermodynamic and structural data generated from our MD/MC simulations are used as input data to parameterize these thermodynamic models. A detailed analysis of the validity and transferability of the Al-Zr MEAM-2NN potential is presented throughout our work by comparing the predicted properties obtained 4. Ab-initio study of transition metal hydrides Energy Technology Data Exchange (ETDEWEB) Sharma, Ramesh [Dept. of Physics, Feroze Gandhi Insititute of Engineering and Technology, Raebareli-229001 (India); Shukla, Seema, E-mail: sharma.yamini62@gmail.com; Dwivedi, Shalini, E-mail: sharma.yamini62@gmail.com; Sharma, Yamini, E-mail: sharma.yamini62@gmail.com [Theoretical Condensed Matter Physics Laboratory, Dept. of Physics Feroze Gandhi College, Raebareli-229001 (India) 2014-04-24 We have performed ab initio self consistent calculations based on Full potential linearized augmented plane wave (FP-LAPW) method to investigate the optical and thermal properties of yttrium hydrides. From the band structure and density of states, the optical absorption spectra and specific heats have been calculated. The band structure of Yttrium metal changes dramatically due to hybridization of Y sp orbitals with H s orbitals and there is a net charge transfer from metal to hydrogen site. The electrical resistivity and specific heats of yttrium hydrides are lowered but the thermal conductivity is slightly enhanced due to increase in scattering from hydrogen sites. 5. Mn in misch-metal based superlattice metal hydride alloy - Part 1 structural, hydrogen storage and electrochemical properties Science.gov (United States) Young, K.; Wong, D. F.; Wang, L.; Nei, J.; Ouchi, T.; Yasuoka, S. 2015-03-01 The structural, gaseous phase hydrogen storage, and electrochemical properties of a series of Mn-modified misch-metal based superlattice metal hydride alloys were investigated in part one of this two-part series of papers. X-ray diffraction analysis showed that these alloys are all multi-phased compositions with different abundances of AB2, AB3, A2B7, AB4, and AB5 phases. Substitution of Ni in the B-site by Mn promotes AB5 phase formation and decreases both gaseous phase and electrochemical capacities due to the reduction in the abundance of main hexagonal A2B7 phase. AC impedance and magnetic susceptibility measurement were employed to characterize the surface of Mn-free and Mn-modified alloys and show deterioration in surface catalytic ability as the Mn-content increases. Mn-modification adversely affected misch-metal based superlattice metal hydride alloy properties such as phase homogeneity, capacity, cycle stability, high-rate performance, and surface reaction. 6. Burning characteristics of individual aluminum/aluminum oxide particles OpenAIRE Ruttenberg, Eric C. 1996-01-01 Approved for public release; distribution is unlimited An experimental investigation was conducted in which the burning characteristics of individual aluminum/aluminum oxide particles were measured using a windowed combustion bomb at atmospheric pressure and under gravity-fall conditions. A scanning electron microscope (SEM) was used to measure the size distribution of the initial aluminum particles and the aluminum oxide residue. Analysis of the residue indicated that the mass of aluminum... 7. Purifying Aluminum by Vacuum Distillation Science.gov (United States) Du Fresne, E. R. 1985-01-01 Proposed method for purifying aluminum employs one-step vacuum distillation. Raw material for process impure aluminum produced in electrolysis of aluminum ore. Impure metal melted in vacuum. Since aluminum has much higher vapor pressure than other constituents, boils off and condenses on nearby cold surfaces in proportions much greater than those of other constituents. 8. A coupled transport and solid mechanics formulation with improved reaction kinetics parameters for modeling oxidation and decomposition in a uranium hydride bed. Energy Technology Data Exchange (ETDEWEB) Salloum, Maher N.; Shugard, Andrew D.; Kanouff, Michael P.; Gharagozloo, Patricia E. 2013-03-01 Modeling of reacting flows in porous media has become particularly important with the increased interest in hydrogen solid-storage beds. An advanced type of storage bed has been proposed that utilizes oxidation of uranium hydride to heat and decompose the hydride, releasing the hydrogen. To reduce the cost and time required to develop these systems experimentally, a valid computational model is required that simulates the reaction of uranium hydride and oxygen gas in a hydrogen storage bed using multiphysics finite element modeling. This SAND report discusses the advancements made in FY12 (since our last SAND report SAND2011-6939) to the model developed as a part of an ASC-P&EM project to address the shortcomings of the previous model. The model considers chemical reactions, heat transport, and mass transport within a hydride bed. Previously, the time-varying permeability and porosity were considered uniform. This led to discrepancies between the simulated results and experimental measurements. In this work, the effects of non-uniform changes in permeability and porosity due to phase and thermal expansion are accounted for. These expansions result in mechanical stresses that lead to bed deformation. To describe this, a simplified solid mechanics model for the local variation of permeability and porosity as a function of the local bed deformation is developed. By using this solid mechanics model, the agreement between our reacting bed model and the experimental data is improved. Additionally, more accurate uranium hydride oxidation kinetics parameters are obtained by fitting the experimental results from a pure uranium hydride oxidation measurement to the ones obtained from the coupled transport-solid mechanics model. Finally, the coupled transport-solid mechanics model governing equations and boundary conditions are summarized and recommendations are made for further development of ARIA and other Sandia codes in order for them to sufficiently implement the model. 9. First-Principles Study of the γAngle Deformation Path in the Wurtzite-to-Rocksalt Phase Transition in Aluminum Nitride Institute of Scientific and Technical Information of China (English) CAI Ying-Xiang; XU Rui 2010-01-01 @@ A new transition path(γangle deformation path)is put forward and used to characterize the wurtzite-rocksalt transition in AlN.The enthalpy surface and the contour plot of enthalpy difference at equilibrium pressure are obtained by first-principles pseudopotential method within the generalized gradient approximation.The phase transition is needed to overcome two barriers and a metaphase arises between them.The total barrier height is0.26eV. 10. Chemical Hydride Slurry for Hydrogen Production and Storage Energy Technology Data Exchange (ETDEWEB) McClaine, Andrew W 2008-09-30 The purpose of this project was to investigate and evaluate the attractiveness of using a magnesium chemical hydride slurry as a hydrogen storage, delivery, and production medium for automobiles. To fully evaluate the potential for magnesium hydride slurry to act as a carrier of hydrogen, potential slurry compositions, potential hydrogen release techniques, and the processes (and their costs) that will be used to recycle the byproducts back to a high hydrogen content slurry were evaluated. A 75% MgH2 slurry was demonstrated, which was just short of the 76% goal. This slurry is pumpable and storable for months at a time at room temperature and pressure conditions and it has the consistency of paint. Two techniques were demonstrated for reacting the slurry with water to release hydrogen. The first technique was a continuous mixing process that was tested for several hours at a time and demonstrated operation without external heat addition. Further work will be required to reduce this design to a reliable, robust system. The second technique was a semi-continuous process. It was demonstrated on a 2 kWh scale. This system operated continuously and reliably for hours at a time, including starts and stops. This process could be readily reduced to practice for commercial applications. The processes and costs associated with recycling the byproducts of the water/slurry reaction were also evaluated. This included recovering and recycling the oils of the slurry, reforming the magnesium hydroxide and magnesium oxide byproduct to magnesium metal, hydriding the magnesium metal with hydrogen to form magnesium hydride, and preparing the slurry. We found that the SOM process, under development by Boston University, offers the lowest cost alternative for producing and recycling the slurry. Using the H2A framework, a total cost of production, delivery, and distribution of$4.50/kg of hydrogen delivered or $4.50/gge was determined. Experiments performed at Boston 11. Corrosion Inhibitors for Aluminum. Science.gov (United States) Muller, Bodo 1995-01-01 Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR) 12. Investigation of increased hydriding of guide tubes in Ringhals 2 during cycle startup International Nuclear Information System (INIS) There are two main sources for hydrogen uptake into Zr alloy components. Beside the uptake of hydrogen from the corrosion reaction, direct uptake of hydrogen from the PWR primary water is the second source and can occur under certain conditions. In Ringhals 2, two guide tubes broke during insertion of control rods in the pool during the outage in 1990 resulting from high hydrogen contents which were found in the Zry-4 guide tubes. The hydrogen content showed large variations between different guide tubes from the same assembly at the same axial elevation. In extreme cases, rims of massive hydrides were seen at the inner surface. In the most affected guide tubes, the oxide thickness at the ID was about 20 μm whereas normal oxide was only about 5 μm. Hot cell examination revealed that the hydrogen content was up to 3000 ppm (average in wall thickness) which means that the hydrogen pickup fraction was well above 100 %. This was a clear indication that a significant amount of hydrogen was stemming from a different source than corrosion. The inner surfaces of these particular guide tubes were grit-blasted with a stainless steel lance. The root-cause analysis revealed by SEM and GDOS that the grit-blasting with such a lance resulted in embedding small stainless steel particles at the guide tube inner surface which in-pile acted as 'hydrogen windows'. When Ni deposited on the surface during the start-up procedure, hydrogen was picked up catalytically after it was added to the coolant at about 150 deg. C. Autoclave tests simulating the start up of a PWR were used to demonstrate the increased hydrogen pickup. The tests showed that this type of accelerated hydriding can be reproduced in the laboratory with guide tube samples grit-blasted on the inside. A necessary condition was that Ni in the coolant was high during the start-up phase and hydrogen was added to the water before the formation of a protective oxide layer can prevent the hydrogen uptake. The tests revealed a 13. Experimental design and simulation of a metal hydride hydrogen storage system Science.gov (United States) Gadre, Sarang Ajit Metal hydrides, as a hydrogen storage medium, have been under consideration for many years because they have the ability to store hydrogen reversibly in the solid state at relatively low pressures and ambient temperatures. The utility of metal hydrides as a hydrogen storage medium was demonstrated recently by the Savannah River Technology Center (SRTC) in an on-board hydrogen storage system for a hybrid electric bus project. The complex geometry and the intricate design of the SRTC bed presents quite a challenge to the development of a mathematical model that can be used for design and optimization. In a new approach introduced here, the reversible reaction kinetics and the empirical Van't Hoff relationship used in a typical reactor model are replaced by a solid phase diffusion equation and one of the two semi-empirical equilibrium P-C-T relationships based on modified virial and composite Langmuir isotherm expressions. Starting with the simplest mathematical formulation, which resulted in an analytical expression, various models were developed and successively improved by relaxing certain assumptions, eventually resulting in the most rigorous model yet developed for this system. All of these models were calibrated using experimental pressure and temperature histories obtained from a bench scale hydrogen storage test facility. The heat and mass transfer coefficients or the thermal conductivity were the only adjustable parameters in these models. A design of experiments approach was also used for studying the effect of various factors on the performance of this bench scale hydrogen storage unit. Overall, the results of this study demonstrated that even a fairly simple numerical model could do a reasonable job in predicting the discharge behavior of a fairly complicated, metal hydride hydrogen storage bed over a wide range of operating conditions. The more rigorous 2-D model gave considerable insight into the dynamics of the hydrogen discharge process from an 14. CORROSION PROTECTION OF ALUMINUM Science.gov (United States) Dalrymple, R.S.; Nelson, W.B. 1963-07-01 Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.) 15. Different failure modes for V-containing and V-free AB2 metal hydride alloys Science.gov (United States) Young, K.; Wong, D. F.; Yasuoka, S.; Ishida, J.; Nei, J.; Koch, J. 2014-04-01 Failure modes of a V-containing and a V-free AB2 Laves phase-based metal hydride alloy were studied by the combination of X-ray diffractometer, scanning electron microscope, X-ray energy dispersive spectroscopy, inductively coupled plasma, Soxhlet extraction, and magnetic susceptibility measurement. Cells with the V-containing alloy exhibited less capacity degradation up until venting occurred in the cells, after which the capacity rapidly degraded. Cells with the V-free alloy remained linear in capacity degradation throughout the cycle life test. The failure mechanism for the V-containing alloy is related to the formation of an oxide layer that penetrates deeper into the alloy particles due to high V leaching and impedes gas recombination, while the failure mechanism for the V-free alloy is related to the continuous pulverization of the main AB2 phase. 16. Effect of loaded organic phase containing mixtures of silicon and aluminum,single iron on extraction of lanthanum in saponification P507-HCl system Institute of Scientific and Technical Information of China (English) WU Wenyuan; ZHANG Fengyun; BIAN Xue; XUE Shoufeng; YIN Shaohua; ZHENG Qiang 2013-01-01 Emulsification troubled normal extraction process of rare earths due to the existence of non-rare earth impurities,especially Si,Al and Fe.Against this background,the effect of emulsification caused by Si,Al and Fe on the La extraction with saponification P507 (2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester) in chloride medium was systematically investigated.A series of experiments were carried out to study the relationship of the extraction capacity of La and the concentration of impurities.ZPM-203 polarizing microscope was applied to investigate the morphology of emulsification,and the cation exchange extraction mechanism of Fe and Al as well as La was clarified by IR spectra.The results showed that a low concentration of Si in organic phase would aggravate the emulsification with A1,and the formation of ME (micro emulsion) and club-shaped polymer would result in emulsification in the extraction of mixtures of Si and A1,single Fe,respectively.Furthermore,the accumulation of impurity such as Si,Al and Fe in the organic phase would severely reduce the extraction capacity of La simultaneously. 17. Comparison of irradiation hardening and microstructure evolution in ion-irradiated delta and epsilon hydrides Energy Technology Data Exchange (ETDEWEB) Oono, Naoko, E-mail: n-oono@eng.hokudai.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kasada, Ryuta [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Higuchi, Toru; Sakamoto, Kan; Nakatsuka, Masafumi [Nippon Nuclear Fuel Development Co., Ltd., 2163 Naritacho Oarai, Higashi-Ibaraki, Ibaraki 311-1313 (Japan); Hasegawa, Akiko; Kondo, Sosuke; Iwata, Noriyuki Y.; Matsui, Hideki; Kimura, Akihiko [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan) 2013-11-15 A δ-Zr-hydride was irradiated with 6.4 MeV Fe{sup 3+} ions to clarify the relationship between hardening and microstructural changes of bulk Zr-hydrides under neutron irradiation. Irradiation hardening was measured by nanoindentation tests. Transmission electron microscope cross-sectional observations showed that the deformation mechanism of the δ-Zr-hydride was both slip and twinning. Dislocation loops were observed in the irradiated hydride matrix. These irradiation-induced defects make slip deformation difficult and consequently promote the twin deformation of δ-Zr-hydride. This work is a continuation of the previous our work (J. Nucl. Mater. 419 (2011) 366–370) focused upon ε-Zr-hydride and we discuss a comparison between the two Zr-hydrides. 18. Growth and decomposition of Lithium and Lithium hydride on Nickel DEFF Research Database (Denmark) Engbæk, Jakob; Nielsen, Gunver; Nielsen, Jane Hvolbæk; 2006-01-01 In this paper we have investigated the deposition, structure and decomposition of lithium and lithium-hydride films on a nickel substrate. Using surface sensitive techniques it was possible to quantify the deposited Li amount, and to optimize the deposition procedure for synthesizing lithium... 19. Process of forming a sol-gel/metal hydride composite Science.gov (United States) Congdon, James W. 2009-03-17 An external gelation process is described which produces granules of metal hydride particles contained within a sol-gel matrix. The resulting granules are dimensionally stable and are useful for applications such as hydrogen separation and hydrogen purification. An additional coating technique for strengthening the granules is also provided. 20. Structural deformation of metallic uranium surrounding hydride growth sites International Nuclear Information System (INIS) Highlights: • UH3 formation on uranium surfaces by a controlled uptake of hydrogen at 240 °C. • Large hydride growths (35–125 μm in diameter) form at the surface. • Confined hydride expansion during growth generates stress in the subsurface. • EBSD scans found micro-cracking and twins as forms of stress relief in the metal. - Abstract: Electron backscatter diffraction (EBSD) was utilised to probe the microstructure of uranium metal in the vicinity of surface corrosion pits, resulting from hydrogen exposure (5 × 104 Pa, at 240 °C). Microstructural analysis of the surface revealed a subtle increase of grain orientation variation for grains at the border of the hydride growths. Cross sectional analysis, at pit sites, revealed significant microstructure deformation in the form of crystal twinning and micro-cracking beneath the surface. These observations provide qualitative evidence that local stress intensities generated as a consequence of hydride growth and confinement, were sufficient to cause deformation within the parent metal 1. Design and integration of a hydrogen storage on metallic hydrides International Nuclear Information System (INIS) This work presents a hydrogen storage system using metal hydrides for a Combined Heat and Power (CHP) system. Hydride storage technology has been chosen due to project specifications: high volumetric capacity, low pressures (≤ 3.5 bar) and low temperatures (≤ 75 C: fuel cell temperature). During absorption, heat from hydride generation is dissipated by fluid circulation. An integrated plate-fin type heat exchanger has been designed to obtain good compactness and to reach high absorption/desorption rates. At first, the storage system has been tested in accordance with project specifications (absorption 3.5 bar, desorption 1.5 bar). Then, the hydrogen charge/discharge times have been decreased to reach system limits. System design has been used to simulate thermal and mass comportment of the storage tank. The model is based on the software Fluent. We take in consideration heat and mass transfers in the porous media during absorption/desorption. The hydride thermal and mass behaviour has been integrated in the software. The heat and mass transfers experimentally obtained have been compared to results calculated by the model. The influence of experimental and numerical parameters on the model behaviour has also been explored. (author) 2. Diffusion model of delayed hydride cracking in zirconium alloys NARCIS (Netherlands) Shmakov, AA; Kalin, BA; Matvienko, YG; Singh, RN; De, PK 2004-01-01 We develop a method for the evaluation of the rate of delayed hydride cracking in zirconium alloys. The model is based on the stationary solution of the phenomenological diffusion equation and the detailed analysis of the distribution of hydrostatic stresses in the plane of a sharp tensile crack. Th 3. Electrochromism of Mg-Ni hydride switchable mirrors Science.gov (United States) Isidorsson, Jan; Giebels, I. A. M. E.; Di Vece, M.; Griessen, Ronald 2001-11-01 Switchable mirrors have so far been made of rare-earth and rare-earth-magnesium based metal-hydrides. In this investigation we study Mg-Ni-hydrides, which have been shown by Richardson et al. to exhibit switchable properties similar to those of the rare-earth hydrides. Cyclic voltammetry on MgzNiHx samples with 0.8 less than z less than 3.7 shows that addition of one Mg atom per Mg2Ni gives the best ab/desorption kinetics for hydrogen. X- ray diffraction reveals a structural change as hydrogen is absorbed. The metal-insulator transition is confirmed with simultaneous resistivity measurements. A pressure- composition isotherm of Mg2NiHx is also determined electrochemically. Optical spectrometry during gas loading gives an optical band gap of 1.6 eV for Mg2NiH4. This gap increases with increasing Mg content in a way similar to that of the Mg-doped rare-earth hydrides. 4. Hydrogen Storage in Porous Materials and Magnesium Hydrides NARCIS (Netherlands) Grzech, A. 2013-01-01 In this thesis representatives of two different types of materials for potential hydrogen storage application are presented. Usage of either nanoporous materials or metal hydrides has both operational advantages and disadvantages. A main objective of this thesis is to characterize the hydrogen stora 5. DFT modeling of the electronic and magnetic structures and chemical bonding properties of intermetallic hydrides International Nuclear Information System (INIS) This thesis presents an ab initio study of several classes of intermetallics and their hydrides. These compounds are interesting from both a fundamental and an applied points of view. To achieve this aim two complementary methods, constructed within the DFT, were chosen: (i) pseudo potential based VASP for geometry optimization, structural investigations and electron localization mapping (ELF), and (ii) all-electrons ASW method for a detailed description of the electronic structure, chemical bonding properties following different schemes as well as quantities depending on core electrons such as the hyperfine field. A special interest is given with respect to the interplay between magneto-volume and chemical interactions (metal-H) effects within the following hydrided systems: binary Laves (e.g. ScFe2) and Haucke (e.g. LaNi5) phases on one hand, and ternary cerium based (e.g. CeRhSn) and uranium based (e.g. U2Ni2Sn) alloys on the other hand. (author) 6. A Novel Zr-1Nb Alloy and a New Look at Hydriding Energy Technology Data Exchange (ETDEWEB) Robert D. Mariani; James I. Cole; Assel Aitkaliyeva 2013-09-01 A novel Zr-1Nb has begun development based on a working model that takes into account the hydrogen permeabilities for zirconium and niobium metals. The beta-Nb secondary phase particles (SPPs) in Zr-1Nb are believed to promote more rapid hydrogen dynamics in the alloy in comparison to other zirconium alloys. Furthermore, some hydrogen release is expected at the lower temperatures corresponding to outages when the partial pressure of H2 in the coolant is less. These characteristics lessen the negative synergism between corrosion and hydriding that is otherwise observed in cladding alloys without niobium. In accord with the working model, development of nanoscale precursors was initiated to enhance the performance of existing Zr-1Nb alloys. Their characteristics and properties can be compared to oxide-dispersion strengthened alloys, and material additions have been proposed to zirconium-based LWR cladding to guard further against hydriding and to fix the size of the SPPs for microstructure stability enhancements. A preparative route is being investigated that does not require mechanical alloying, and 10 nanometer molybdenum particles have been prepared which are part of the nanoscale precursors. If successful, the approach has implications for long term dry storage of used fuel and for new routes to nanoferritic and ODS alloys. 7. Separation of trace antimony and arsenic prior to hydride generation atomic absorption spectrometric determination International Nuclear Information System (INIS) A separation method utilizing a synthetic zeolite (mordenite) was developed in order to eliminate the gas phase interference of Sb(III) on As(III) during quartz furnace hydride generation atomic absorption spectrometric (HGAAS) determination. The efficiency of the proposed separation method in the reduction of suppression effects of transition metal ions on As(III) signal was also investigated. Among the volatile hydride-forming elements and their different oxidation states tested (Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), and Te(VI)), only Sb(III) was found to have a signal depression effect even at low (μg l-1) concentrations under the experimental conditions employed. It has been shown that mordenite adsorbs Sb(III) quantitatively, even at a concentration of 1000 μg l-1, at pHs greater than two, and also, it reduces the initial concentrations of the transition metal ions to lower levels which can be tolerated in many studies. The adsorption of Sb(III) on mordenite follows the Freundlich isotherm and is endothermic in nature 8. Active-Transient Liquid Phase (A-TLP) Bonding of Pure Aluminum Matrix Composite Reinforced with Short Alumina Fiber Using Al-12Si- xTi Foils as Active Interlayer Science.gov (United States) Zhang, Guifeng; Su, Wei; Suzumura, Akio 2016-06-01 To optimize both the interlayer composition design route and pressure for joining aluminum matrix composite reinforced with short alumina fiber (as-cast 30 vol pct Al2O3sf/Al), traditional transient liquid phase (TLP) bonding using Al-12Si and Cu interlayer and active-TLP (A-TLP) bonding using an active Ti-containing interlayer (Al-12Si- xTi, x = 0.1, 0.5, and 1 wt pct) under the same condition [883 K (610 °C) × 30 minutes × 1 or 0.015 MPa in flowing argon] were compared in terms of interfacial wettability, bond seam microstructure, shear strength, and fracture path. It was found that not only the Ti content but also the pressure are critical factors affecting interfacial wettability and bond seam microstructure. The improvement in wettability by adding Ti as an active element were confirmed by reduction of expulsion of liquid interlayer, elimination of interfacial gap, higher shear strength and favorable fracture path (partially through bond seam and the composite). Because of the incubation period for wetting, reducing the pressure after melting of the interlayer could further increase joint shear strength by thickening the remaining bond seam of solid-solution matrix and decreasing fraction of the in situ newly formed Al-Si-Ti IMC phase (short bar shape) within the bond seam. The maximum shear strength of 88.6 MPa (99 pct of the as-cast composite) was obtained by adding trace Ti content (0.5 Ti wt pct) addition and using low pressure (0.015 MPa). The results showed that suitable combination of Ti content and pressure pattern is required for improving both wettability and bond seam microstructure. 9. Effect of high heating rate on thermal decomposition behaviour of titanium hydride (TiH2) powder in air Indian Academy of Sciences (India) A Rasooli; M A Boutorabi; M Divandari; A Azarniya 2013-04-01 DTA and TGA curves of titanium hydride powder were determined in air at different heating rates. Also the thermal decomposition behaviour of the aforementioned powder at high heating rates was taken into consideration. A great breakthrough of the practical interest in the research was the depiction of the H2-time curves of TiH2 powder at various temperatures in air. In accordance with the results, an increase in heating rate to higher degrees does not change the process of releasing hydrogen from titanium hydride powder, while switching it from internal diffusion to chemical reaction. At temperatures lower than 600 °C, following the diffusion of hydrogen and oxygen atoms in titanium lattice, thin layers TiH phase and oxides form on the powder surface, controlling the process. On the contrary, from 700 °C later on, the process is controlled by oxidation of titanium hydride powder. In fact, the powder oxidation starts around 650 °C and may escalate following an increase in the heating rate too. 10. Hydrogenation of AB{sub 5} and AB{sub 2} metal hydride alloys studied by in situ X-ray diffraction Energy Technology Data Exchange (ETDEWEB) Wang, L. [Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202 (United States); BASF – Battery Materials Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States); Young, K., E-mail: kwo.young@basf.com [BASF – Battery Materials Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States); Nei, J.; Pawlik, D. [BASF – Battery Materials Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309 (United States); Ng, K.Y.S. [Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202 (United States) 2014-12-15 Highlights: • Hydrogenation process of an AB{sub 5} alloy and two AB{sub 2} alloys were studied by quasi in-situ XRD. • In both AB{sub 5} and AB{sub 2} metal alloy, hydrogen occupation sites on the half-plane were taken first. • In the C14/C15 mixed alloy, C14 phase is the main hydrogen storage phase with a lower equilibrium pressure. • In the C14/C15 mixed alloy, C15 phase is the catalyst hydrogen storage phase with a higher equilibrium pressure. • Small amount of C15 was hydrided first but not completed until C14 phase was fully hydrided. - Abstract: The evolution of lattice constants and abundances of metal (α) and metal hydride (β) phases during the hydrogenation process of an AB{sub 5} alloy with a CaCu{sub 5} crystal structure, an AB{sub 2} alloy with a predominating C14 structure, and a C14/C15-mixed AB{sub 2} alloy were reported. The preferred hydrogen insertion sites at different states of charge in both the α and β phases were studied based on the lattice parameter changes during hydrogenation. During the hydrogenation of the AB{sub 5} alloy, the ratio between lattice parameters a and c (a/c ratio) in the α phase decreases, stabilizes, and then decreases again while that in the β phase decreases and then stabilizes. The trends in unit cell volume changes are increasing, plateauing, and increasing again in the α phase and increasing followed by plateauing in the β phase as the hydrogenation level increases. In the C14-predominant AB{sub 2} alloy, the a/c ratio in the α phase increases at the beginning and then stabilizes while that in the β phase remains about the same and then increases during the addition of hydrogen. Moreover, the unit cell volume in the α phase increases slightly during hydrogenation, comparing to the increasing, decreasing, and then increasing trend in the β phase. In the C14/C15 mixed AB{sub 2} alloy, hydrogenation of the C15 phase starts at the beginning and promotes the hydrogenation of the C14 phase. The C14 11. In Situ Investigation of Hydride Precipitation and Growth in Zircaloy-4 by Transmission Electron Microscopy%Zr-4合金中氢化物析出长大的透射电镜原位研究 Institute of Scientific and Technical Information of China (English) 彭剑超; 李强; 刘仁多; 姚美意; 周邦新 2011-01-01 用透射电子显微镜拉伸试样台原位研究了应力、电子束辐照以及第二相对Zr-4合金中氢化物析出和长大的影响.结果表明,在拉应力作用下,裂纹易于沿氢化物扩展,并在裂尖垂直于拉应力方向析出新的氢化物.氢化物在拉应力诱发下的析出、开裂、再析出……过程,导致了氢致延迟开裂.在较强的会聚电子束辐照下,Zr-4合金中的氢化物会分解,新的氢化物会围绕着附近的Zr(Fe,Cr)2第二相粒子析出,新析出的氢化物为面心立方结构的δ相.%The effects of stress, electron beam irradiation and second phase particles on zirconium hydride precipitation and growth in Zircaloy-4 were investigated using in-situ transmission electron microscope observation. Results show that with the tensile stress the cracks are likely to propagate along hydrides and new hydrides are formed at the crack tip along the vertical direction of the applied stress. A process of precipitation, cracking, re-precipitation and so on, induced by tensile stress, causes delayed hydride cracking (DHC). Under the high irradiation of converged electron beam, the hydrides decompose in the Zircaloy-4, and new hydrides prefer to precipitate around the unoxidized Zr(Fe, Cr>2 particles, and the re-precipitated hydrides are fcc-structure 8 phase. 12. Synthesis of hydrides by interaction of intermetallic compounds with ammonia Energy Technology Data Exchange (ETDEWEB) Tarasov, Boris P., E-mail: tarasov@icp.ac.ru [Institute of Problems of Chemical Physics of the Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Fokin, Valentin N.; Fokina, Evelina E. [Institute of Problems of Chemical Physics of the Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Yartys, Volodymyr A., E-mail: volodymyr.yartys@ife.no [Institute for Energy Technology, Kjeller NO 2027 (Norway); Department of Materials Science and Engineering, Norwegian University of Science and Technology, Trondheim NO 7491 (Norway) 2015-10-05 Highlights: • Interaction of the intermetallics A{sub 2}B, AB, AB{sub 2}, AB{sub 5} and A{sub 2}B{sub 17} with NH{sub 3} was studied. • The mechanism of interaction of the alloys with ammonia is temperature-dependent. • Hydrides, hydridonitrides, disproportionation products or metal–N–H compounds are formed. • NH{sub 4}Cl was used as an activator of the reaction between ammonia and intermetallics. • Interaction with ammonia results in the synthesis of the nanopowders. - Abstract: Interaction of intermetallic compounds with ammonia was studied as a processing route to synthesize hydrides and hydridonitrides of intermetallic compounds having various stoichiometries and types of crystal structures, including A{sub 2}B, AB, AB{sub 2}, AB{sub 5} and A{sub 2}B{sub 17} (A = Mg, Ti, Zr, Sc, Nd, Sm; B = transition metals, including Fe, Co, Ni, Ti and nontransition elements, Al and B). In presence of NH{sub 4}Cl used as an activator of the reaction between ammonia and intermetallic alloys, their interaction proceeds at rather mild P–T conditions, at temperatures 100–200 °C and at pressures of 0.6–0.8 MPa. The mechanism of interaction of the alloys with ammonia appears to be temperature-dependent and, following a rise of the interaction temperature, it leads to the formation of interstitial hydrides; interstitial hydridonitrides; disproportionation products (binary hydride; new intermetallic hydrides and binary nitrides) or new metal–nitrogen–hydrogen compounds like magnesium amide Mg(NH{sub 2}){sub 2}. The interaction results in the synthesis of the nanopowders where hydrogen and nitrogen atoms become incorporated into the crystal lattices of the intermetallic alloys. The nitrogenated materials have the smallest particle size, down to 40 nm, and a specific surface area close to 20 m{sup 2}/g. 13. Chronic aluminum intake causes Alzheimer's disease: applying Sir Austin Bradford Hill's causality criteria. Science.gov (United States) Walton, J R 2014-01-01 Industrialized societies produce many convenience foods with aluminum additives that enhance various food properties and use alum (aluminum sulfate or aluminum potassium sulfate) in water treatment to enable delivery of large volumes of drinking water to millions of urban consumers. The present causality analysis evaluates the extent to which the routine, life-long intake, and metabolism of aluminum compounds can account for Alzheimer's disease (AD), using Austin Bradford Hill's nine epidemiological and experimental causality criteria, including strength of the relationship, consistency, specificity, temporality, dose-dependent response, biological rationale, coherence with existing knowledge, experimental evidence, and analogy. Mechanisms that underlie the risk of low concentrations of aluminum relate to (1) aluminum's absorption rates, allowing the impression that aluminum is safe to ingest and as an additive in food and drinking water treatment, (2) aluminum's slow progressive uptake into the brain over a long prodromal phase, and (3) aluminum's similarity to iron, in terms of ionic size, allows aluminum to use iron-evolved mechanisms to enter the highly-active, iron-dependent cells responsible for memory processing. Aluminum particularly accumulates in these iron-dependent cells to toxic levels, dysregulating iron homeostasis and causing microtubule depletion, eventually producing changes that result in disconnection of neuronal afferents and efferents, loss of function and regional atrophy consistent with MRI findings in AD brains. AD is a human form of chronic aluminum neurotoxicity. The causality analysis demonstrates that chronic aluminum intake causes AD. 14. Aluminum, parathyroid hormone, and osteomalacia Energy Technology Data Exchange (ETDEWEB) Burnatowska-Hledin, M.A.; Kaiser, L.; Mayor, G.H. 1983-01-01 Aluminum exposure in man is unavoidable. The occurrence of dialysis dementia, vitamin D-resistant osteomalacia, and hypochromic microcytic anemia in dialysis patients underscores the potential for aluminum toxicity. Although exposure via dialysate and hyperalimentation leads to significant tissue aluminum accumulation, the ubiquitous occurrence of aluminum and the severe pathology associated with large aluminum burdens suggest that smaller exposures via the gastrointestinal tract and lungs could represent an important, though largely unrecognized, public health problem. It is clear that some aluminum absorption occurs with the ingestion of small amounts of aluminum in the diet and medicines, and even greater aluminum absorption is seen in individuals consuming large amounts of aluminum present in antacids. Aluminum absorption is enhanced in the presence of elevated circulating parathyroid hormone. In addition, elevated PTH leads to the preferential deposition of aluminum in brain and bone. Consequently, PTH is likely to be involved in the pathogenesis of toxicities in those organs. PTH excess also seems to lead to the deposition of aluminum in the parathyroid gland. The in vitro demonstration that aluminum inhibits parathyroid hormone release is consistent with the findings of a euparathyroid state in dialysis patients with aluminum related vitamin D-resistant osteomalacia. Nevertheless, it seems likely that hyperparathyroidism is at least initially involved in the pathogenesis of aluminum neurotoxicity and osteomalacia; the increases in tissue aluminum stores are followed by suppression of parathyroid hormone release, which is required for the evolution of osteomalacia. Impaired renal function is not a prerequisite for increased tissue aluminum burdens, nor for aluminum-related organ toxicity. Consequently, it is likely that these diseases will be observed in populations other than those with chronic renal disease. 15. The crystallization processes in the aluminum particles production technology Directory of Open Access Journals (Sweden) Arkhipov Vladimir 2015-01-01 Full Text Available The physical and mathematical model of the crystallization process of liquid aluminum particles in the spray-jet of the ejection-type atomizer was proposed. The results of mathematical modeling of two-phase flow in the spray-jet and the crystallization process of fluid particles are given. The influence of the particle size, of the flow rate and the stagnation temperature gas in the ranges of industrial technology implemented for the production of powders aluminum of brands ASD, on the crystallization characteristics were investigated. The approximations of the characteristics of the crystallization process depending on the size of the aluminum particles on the basis of two approaches to the mathematical description of the process of crystallization of aluminum particles were obtained. The results allow to optimize the process parameters of ejection-type atomizer to produce aluminum particles with given morphology. 16. Synthesis and enhanced hydrogen desorption kinetics of magnesium hydride using hydriding chemical vapor synthesis Energy Technology Data Exchange (ETDEWEB) Kim, Jin-Ho [Icheon Branch, Korea Institute of Ceramic Engineering and Technology (KICET), Icheon-si, Gyeonggi-do (Korea, Republic of); Kim, Byung-Goan [Korea Energy Materials Co.Ltd., 409, Daegu Technopark, 1-11, Hosan-Dong, Dalse-Gu 704-230 (Korea, Republic of); Kang, Yong-Mook, E-mail: dake@kaist.ac.kr [Department of Chemistry, Dongguk University-Seoul, 100715 Seoul (Korea, Republic of) 2012-07-15 Highlights: Black-Right-Pointing-Pointer We synthesized pure MgH{sub 2} by a hydriding chemical vapor synthesis process in a hydrogen atmosphere. Black-Right-Pointing-Pointer The particle size HCVS-MgH{sub 2} was drastically reduced to the sub-micron or micrometer-scale. Black-Right-Pointing-Pointer HCVS-MgH{sub 2} showed different shapes (needle-like nanofibers and angulated plate) depending on the deposited position. Black-Right-Pointing-Pointer HCVS-MgH{sub 2} desorbed hydrogen up to about 7.2 wt% and 7.1 wt%. - Abstract: This paper describes the hydriding chemical vapor synthesis (HCVS) of the hydrogen storage alloy MgH{sub 2} in a hydrogen atmosphere and the product's hydrogenation properties. Mg powder was used as a starting material to produce submicron MgH{sub 2} and uniformly heated to a temperature of 600 Degree-Sign C for Mg vaporization. The effects of deposited positions in HCVS reactor on the morphology and the composition of the obtained products were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses. It is clearly seen that after the HCVS process, the particle size of synthesized MgH{sub 2} was drastically reduced to the sub-micron or micrometer-scale and these showed different shapes (needle-like nanofibers and angulated plate) depending on the deposited position. The hydrogen desorption temperatures of HCVS-MgH{sub 2} were measured using a differential scanning calorimeter (DSC). It was found that after the HCVS process, the desorption temperature of HCVS-MgH{sub 2} decreased from 430 to 385 Degree-Sign C and, simultaneously, the smallest particle size and the highest specific surface area were obtained. These observations indicate that the minimum hydrogen desorption temperature of HCVS-MgH{sub 2} powder with needle-like form can be obtained, and that this temperature is dependent on the particle size and the specific surface area of the products. The thermogravimetric 17. Fabrication of aluminum foam from aluminum scrap Hamza Directory of Open Access Journals (Sweden) O. A. Osman1 , 2015-02-01 Full Text Available In this study the optimum parameters affecting the preparation of aluminum foam from recycled aluminum were studied, these parameters are: temperature, CaCO3 to aluminum scrap wt. ratio as foaming agent, Al2O3 to aluminum scrap wt. ratio as thickening agent, and stirring time. The results show that, the optimum parameters are the temperature ranged from 800 to 850oC, CaCO3 to aluminum scrap wt. ratio was 5%, Al2O3 to aluminum scrap wt. ratio was 3% and stirring time was 45 second with stirring speed 1200 rpm. The produced foam apparent densities ranged from 0.40-0.60 g/cm3. The microstructure of aluminum foam was examined by using SEM, EDX and XRD, the results show that, the aluminum pores were uniformly distributed along the all matrices and the cell walls covered by thin oxide film. 18. Composite Materials for Hazard Mitigation of Reactive Metal Hydrides. Energy Technology Data Exchange (ETDEWEB) Pratt, Joseph William; Cordaro, Joseph Gabriel; Sartor, George B.; Dedrick, Daniel E.; Reeder, Craig L. 2012-02-01 In an attempt to mitigate the hazards associated with storing large quantities of reactive metal hydrides, polymer composite materials were synthesized and tested under simulated usage and accident conditions. The composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride. Composites with vinyl-containing siloxane oligomers were also polymerized with and without added styrene and divinyl benzene. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride reduced the inherent hydrogen storage capacity of the material. The composites were found to be initially effective at reducing the amount of heat released during oxidation. However, upon cycling the composites, the mitigating behavior was lost. While the polymer composites we investigated have mitigating potential and are physically robust, they undergo a chemical change upon cycling that makes them subsequently ineffective at mitigating heat release upon oxidation of the metal hydride. Acknowledgements The authors would like to thank the following people who participated in this project: Ned Stetson (U.S. Department of Energy) for sponsorship and support of the project. Ken Stewart (Sandia) for building the flow-through calorimeter and cycling test stations. Isidro Ruvalcaba, Jr. (Sandia) for qualitative experiments on the interaction of sodium alanate with water. Terry Johnson (Sandia) for sharing his expertise and knowledge of metal hydrides, and sodium alanate in particular. Marcina Moreno (Sandia) for programmatic assistance. John Khalil (United Technologies Research Corp) for insight into the hazards of reactive metal hydrides and real-world accident scenario experiments. Summary In an attempt to mitigate and/or manage hazards associated with storing bulk quantities of reactive metal hydrides, polymer composite materials (a mixture of a mitigating polymer and a metal hydride) were synthesized and tested 19. The Nondestructive Determination of the Aluminum Content in Pressed Skulls of Aluminum Dross Science.gov (United States) Kevorkijan, Varuzan; Škapin, Srečo Davor; Kovačec, Uroš 2013-02-01 During production of primary and secondary aluminum, various amounts (in some cases up to 200 kg) of aluminum dross, a mixture consisting of molten aluminum metal and different oxide compounds (the nonmetallic phase), are skimmed per tonne of molten metal. To preserve the maximum aluminum content in hot dross for further extraction, it is necessary to cool the dross immediately after skimming. One way to do this is to press the skimmed hot dross in a press. In this process, the skimmed dross is transformed into so-called pressed skulls, with characteristic geometry convenient for storage, transport, or further in-house processing. Because of its high aluminum content—usually between 30% and 70%—pressed skulls represent a valuable source of aluminum and hence are in great demand in the aluminum recycling industry. Because pressed skulls are generally valued on a free-metal recovery basis, which is influenced by the yield of recovery, or in other words, by the quality of the recycling process, it was recognized as important and useful to develop a method of fast and cost-effective nondestructive measurement of the free aluminum content in pressed skulls, independent of the technology of pressed skulls recycling. In the model developed in this work, the aluminum content in pressed skulls was expressed as a function of the pressed skulls density, the density of the nonmetallic phase, and the volume fraction of closed pores. In addition, the model demonstrated that under precisely defined conditions (i.e., skulls from the dross of the same aluminum alloy and skimmed, transported, cooled, and pressed in the same way and under the same processing conditions), when other parameters except the pressed skulls density remain constant, the aluminum content in pressed skulls can be expressed as a linear function of the pressed skulls density. Following the theoretical considerations presented in this work, a practical industrial methodology was developed for nondestructive 20. The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys Directory of Open Access Journals (Sweden) Kwo-Hsiung Young 2016-07-01 Full Text Available Effects of substitutions of rare earth (RE elements (Y, La, Ce, and Nd to the Zr-based AB2 multi-phase metal hydride (MH alloys on the structure, gaseous phase hydrogen storage (H-storage, and electrochemical properties were studied and compared. Solubilities of the RE atoms in the main Laves phases (C14 and C15 are very low, and therefore the main contributions of the RE additives are through the formation of the RENi phase and change in TiNi phase abundance. Both the RENi and TiNi phases are found to facilitate the bulk diffusion of hydrogen but impede the surface reaction. The former is very effective in improving the activation behaviors. −40 °C performances of the Ce-doped alloys are slightly better than the Nd-doped alloys but not as good as those of the La-doped alloys, which gained the improvement through a different mechanism. While the improvement in ultra-low-temperature performance of the Ce-containing alloys can be associated with a larger amount of metallic Ni-clusters embedded in the surface oxide, the improvement in the La-containing alloys originates from the clean alloy/oxide interface as shown in an earlier transmission electron microscopy study. Overall, the substitution of 1 at% Ce to partially replace Zr gives the best electrochemical performances (capacity, rate, and activation and is recommended for all the AB2 MH alloys for electrochemical applications. 1. Aluminum Hydroxide and Magnesium Hydroxide Science.gov (United States) Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ... 2. Lightweight Aluminum/Nano composites for Automotive Drive Train Applications Energy Technology Data Exchange (ETDEWEB) Chelluri, Bhanumathi; Knoth, Edward A.; Schumaker, Edward J. 2012-12-14 During Phase I, we successfully processed air atomized aluminum powders via Dynamic Magnetic Compaction (DMC) pressing and subsequent sintering to produce parts with properties similar to wrought aluminum. We have also showed for the first time that aluminum powders can be processed without lubes via press and sintering to 100 % density. This will preclude a delube cycle in sintering and promote environmentally friendly P/M processing. Processing aluminum powders via press and sintering with minimum shrinkage will enable net shape fabrication. Aluminum powders processed via a conventional powder metallurgy process produce too large a shrinkage. Because of this, sinter parts have to be machined into specific net shape. This results in increased scrap and cost. Fully sintered aluminum alloy under this Phase I project has shown good particle-to-particle bonding and mechanical properties. We have also shown the feasibility of preparing nano composite powders and processing via pressing and sintering. This was accomplished by dispersing nano silicon carbide (SiC) powders into aluminum matrix comprising micron-sized powders (<100 microns) using a proprietary process. These composite powders of Al with nano SiC were processed using DMC press and sinter process to sinter density of 85-90%. The process optimization along with sintering needs to be carried out to produce full density composites. 3. Characterization of salt cake from secondary aluminum production. Science.gov (United States) Huang, Xiao-Lan; Badawy, Amro El; Arambewela, Mahendranath; Ford, Robert; Barlaz, Morton; Tolaymat, Thabet 2014-05-30 Salt cake is a major waste component generated from the recycling of secondary aluminum processing (SAP) waste. Worldwide, the aluminum industry produces nearly 5 million tons of waste annually and the end-of-life management of these wastes is becoming a challenge in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 39 SAP waste salt cake samples collected from 10 different facilities across the U.S. were determined. The results showed that aluminum (Al), aluminum oxide, aluminum nitride and its oxides, spinel and elpasolite are the dominant aluminum mineral phases in salt cake. The average total Al content was 14% (w/w). The overall percentage of the total leachable Al in salt cake was 0.6% with approximately 80% of the samples leaching at a level less than 1% of the total aluminum content. The extracted trace metal concentrations in deionized water were relatively low (μgL(-1) level). The toxicity characteristic leaching procedure (TCLP) was employed to further evaluate leachability and the results indicated that the leached concentrations of toxic metals from salt cake were much lower than the EPA toxicity limit set by USEPA. 4. China’s Aluminum Resources Institute of Scientific and Technical Information of China (English) 2004-01-01 <正> The aluminum industry makes one of the keyindustries in China’s industrial and agriculturalmodernization and features a high degree ofrelevance with all industries.Of all the 124existing industries in China,113 use aluminum,representing an industrial relevance rate of91%.The consumption of aluminum is also ofhigh relevance with China’s GDP. 5. Effects of metastability on hydrogen sorption in fluorine substituted hydrides Energy Technology Data Exchange (ETDEWEB) Pinatel, E.R.; Corno, M.; Ugliengo, P.; Baricco, M., E-mail: marcello.baricco@unito.it 2014-12-05 Highlights: • Fluorine substitution in simple metal hydrides has been modelled. • The stability of the MH{sub (1−x)}F{sub x} solid solutions has been discussed. • Conditions for reversibility of sorption reactions have been suggested. - Abstract: In this work ab initio calculations and Calphad modelling have been coupled to describe the effect of fluorine substitution on the thermodynamics of hydrogenation–dehydrogenation in simple hydrides (NaH, AlH{sub 3} and CaH{sub 2}). These example systems have been used to discuss the conditions required for the formation of a stable hydride–fluoride solid solution necessary to obtain a reversible hydrogenation reaction. 6. X-ray photoemission spectroscopy study of zirconium hydride International Nuclear Information System (INIS) X-ray photoemission spectroscopy (XPS) measurements are reported for ZrH/sub 1.65/ and Zr metal. The valence-band measurements are compared with available band-theory density-of-states calculations for the metal and hydride. The hydride spectrum differs significantly from the metal spectrum. Most important, a strong peak associated with hydrogen s electrons appears approximately 7 eV below the Fermi level. XPS measurements of Zr 4p core levels show a binding-energy shift of 1 eV between Zr metal and ZrH/sub 1.65/. It is argued that this shift results from charge readjustment in the vicinity of the Zr site. With the addition of hydrogen, net charge must be transferred from the Zr site to the hydrogen site. A charge-density analysis based on simplified cluster calculations is presented 7. Carbon-Fiber/Epoxy Tube Lined With Aluminum Foil Science.gov (United States) Gernet, Nelson J.; Kerr, Gregory K. 1995-01-01 Carbon-fiber/epoxy composite tube lined with welded aluminum foil useful as part of lightweight heat pipe in which working fluid ammonia. Aluminum liner provides impermeability for vacuum seal, to contain ammonia in heat pipe, and to prevent flow of noncondensable gases into heat pipe. Similar composite-material tubes lined with foils also incorporated into radiators, single- and two-phase thermal buses, tanks for storage of cryogenic materials, and other plumbing required to be lightweight. 8. FEASIBILITY OF RECYCLING PLUTONIUM AND MINOR ACTINIDES IN LIGHT WATER REACTORS USING HYDRIDE FUEL International Nuclear Information System (INIS) The objective of this DOE NERI program sponsored project was to assess the feasibility of improving the plutonium (Pu) and minor actinide (MA) recycling capabilities of pressurized water reactors (PWRs) by using hydride instead of oxide fuels. There are four general parts to this assessment: (1) Identifying promising hydride fuel assembly designs for recycling Pu and MAs in PWRs; (2) Performing a comprehensive systems analysis that compares the fuel cycle characteristics of Pu and MA recycling in PWRs using the promising hydride fuel assembly designs identified in Part 1 versus using oxide fuel assembly designs; (3) Conducting a safety analysis to assess the likelihood of licensing hydride fuel assembly designs; and (4) Assessing the compatibility of hydride fuel with cladding materials and water under typical PWR operating conditions Hydride fuel was found to offer promising transmutation characteristics and is recommended for further examination as a possible preferred option for recycling plutonium in PWRs 9. FEASIBILITY OF RECYCLING PLUTONIUM AND MINOR ACTINIDES IN LIGHT WATER REACTORS USING HYDRIDE FUEL Energy Technology Data Exchange (ETDEWEB) Greenspan, Ehud; Todreas, Neil; Taiwo, Temitope 2009-03-10 The objective of this DOE NERI program sponsored project was to assess the feasibility of improving the plutonium (Pu) and minor actinide (MA) recycling capabilities of pressurized water reactors (PWRs) by using hydride instead of oxide fuels. There are four general parts to this assessment: 1) Identifying promising hydride fuel assembly designs for recycling Pu and MAs in PWRs 2) Performing a comprehensive systems analysis that compares the fuel cycle characteristics of Pu and MA recycling in PWRs using the promising hydride fuel assembly designs identified in Part 1 versus using oxide fuel assembly designs 3) Conducting a safety analysis to assess the likelihood of licensing hydride fuel assembly designs 4) Assessing the compatibility of hydride fuel with cladding materials and water under typical PWR operating conditions Hydride fuel was found to offer promising transmutation characteristics and is recommended for further examination as a possible preferred option for recycling plutonium in PWRs. 10. Effect of thermo-mechanical cycling on zirconium hydride reorientation studied in situ with synchrotron X-ray diffraction Science.gov (United States) Colas, Kimberly B.; Motta, Arthur T.; Daymond, Mark R.; Almer, Jonathan D. 2013-09-01 The circumferential hydrides normally present in nuclear reactor fuel cladding after reactor exposure may dissolve during drying for dry storage and re-precipitate when cooled under load into a more radial orientation, which could embrittle the fuel cladding. It is necessary to study the rates and conditions under which hydride reorientation may happen in order to assess fuel integrity in dry storage. The objective of this work is to study the effect of applied stress and thermal cycling on the hydride morphology in cold-worked stress-relieved Zircaloy-4 by combining conventional metallography and in situ X-ray diffraction techniques. Metallography is used to study the evolution of hydride morphology after several thermo-mechanical cycles. In situ X-ray diffraction performed at the Advanced Photon Source synchrotron provides real-time information on the process of hydride dissolution and precipitation under stress during several thermal cycles. The detailed study of diffracted intensity, peak position and full-width at half-maximum provides information on precipitation kinetics, elastic strains and other characteristics of the hydride precipitation process. The results show that thermo-mechanical cycling significantly increases the radial hydride fraction as well as the hydride length and connectivity. The radial hydrides are observed to precipitate at a lower temperature than circumferential hydrides. Variations in the magnitude and range of hydride strains due to reorientation and cycling have also been observed. These results are discussed in light of existing models and experiments on hydride reorientation. The study of hydride elastic strains during precipitation shows marked differences between circumferential and radial hydrides, which can be used to investigate the reorientation process. Cycling under stress above the threshold stress for reorientation drastically increases both the reoriented hydride fraction and the hydride size. The reoriented hydride 11. Inelastic neutron scattering from amorphous hydride of Zr2Pd International Nuclear Information System (INIS) Time-of-flight inelastic neutron scattering data was obtained on hydrided Zr2Pd metallic glass using the Crystal Analyzer Spectrometer at the Los Alamos pulsed spallation neutron source. Energy transfers from about 40 MeV to several hundred MeV were obtained with sufficiently good statistics and signal to noise ratio to show the second harmonic as well as the fundamental hydrogen optic mode 12. Proximity breakdown of hydrides in superconducting niobium cavities OpenAIRE Romanenko, A.; Barkov, F.; Cooley, L. D.; Grassellino, A. 2012-01-01 Many modern and proposed future particle accelerators rely on superconducting radio frequency cavities made of bulk niobium as primary particle accelerating structures. Such cavities suffer from the anomalous field dependence of their quality factors Q0. High field degradation - so-called high field Q-slope - is yet unexplained even though an empirical cure is known. Here we propose a mechanism based on the presence of proximity-coupled niobium hydrides, which can explain this effect. Further... 13. METHOD OF MAKING DELTA ZIRCONIUM HYDRIDE MONOLITHIC MODERATOR PIECES Science.gov (United States) Vetrano, J.B. 1962-01-23 A method is given for preparing large, sound bodies of delta zirconium hydride. The method includes the steps of heating a zirconium body to a temperature of not less than l000 deg C, providing a hydrogen atmosphere for the zirconium body at a pressure not greater than one atmosphere, reducing the temperature slowly to 800 deg C at such a rate that cracks do not form while maintaining the hydrogen pressure substantially constant, and cooling in an atmosphere of hydrogen. (AEC) 14. Pingguo Aluminum Faces Dilemma Institute of Scientific and Technical Information of China (English) 2013-01-01 <正>Chinalco Guangxi Pinggjuo Branch is an exemplary company of Chinalco. Many of its indicators including technology, management standard, and profit rank in leading position in the industry, but such a pace-setter company is also facing the dilemma of overstock of Alumina products, and loss in electrolytic aluminum business. 15. Applied Electrochemistry of Aluminum DEFF Research Database (Denmark) Li, Qingfeng; Qiu, Zhuxian Electrochemistry of aluminum is of special importance from both theoretical and technological point of view. It covers a wide range of electrolyte systems from molten fluoride melts at around 1000oC to room temperature molten salts, from aqueous to various organic media and from liquid to solid... 16. Oxidation of Group 8 transition-Metal Hydrides and Ionic Hydrogenation of Ketones and Aldehydes Energy Technology Data Exchange (ETDEWEB) Smith, Kjell-Tore 1996-08-01 Transition-metal hydrides have received considerable attention during the last decades because of their unusual reactivity and their potential as homogeneous catalysts for hydrogenation and other reactions of organic substrates. An important class of catalytic processes where transition-metal hydrides are involved is the homogeneous hydrogenation of alkenes, alkynes, ketones, aldehydes, arenes and nitro compounds. This thesis studies the oxidation of Group 8 transition-metal hydrides and the ionic hydrogenation of ketones and aldehydes. 17. Another Look at the Mechanisms of Hydride Transfer Enzymes with Quantum and Classical Transition Path Sampling OpenAIRE Dzierlenga, Michael W.; Antoniou, Dimitri; Schwartz, Steven D. 2015-01-01 The mechanisms involved in enzymatic hydride transfer have been studied for years, but questions remain due, in part, to the difficulty of probing the effects of protein motion and hydrogen tunneling. In this study, we use transition path sampling (TPS) with normal mode centroid molecular dynamics (CMD) to calculate the barrier to hydride transfer in yeast alcohol dehydrogenase (YADH) and human heart lactate dehydrogenase (LDH). Calculation of the work applied to the hydride allowed for obser... 18. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications Directory of Open Access Journals (Sweden) Borislav Bogdanović 2009-01-01 Full Text Available For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described. 19. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications OpenAIRE Borislav Bogdanović; Michael Felderhoff 2009-01-01 For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described. 20. Superconductivity of novel tin hydrides (SnnHm) under pressure Science.gov (United States) Mahdi Davari Esfahani, M.; Wang, Zhenhai; Oganov, Artem R.; Dong, Huafeng; Zhu, Qiang; Wang, Shengnan; Rakitin, Maksim S.; Zhou, Xiang-Feng 2016-01-01 With the motivation of discovering high-temperature superconductors, evolutionary algorithm USPEX is employed to search for all stable compounds in the Sn-H system. In addition to the traditional SnH4, new hydrides SnH8, SnH12 and SnH14 are found to be thermodynamically stable at high pressure. Dynamical stability and superconductivity of tin hydrides are systematically investigated. Im2-SnH8, C2/m-SnH12 and C2/m-SnH14 exhibit higher superconducting transition temperatures of 81, 93 and 97 K compared to the traditional compound SnH4 with Tc of 52 K at 200 GPa. An interesting bent H3–group in Im2-SnH8 and novel linear H in C2/m-SnH12 are observed. All the new tin hydrides remain metallic over their predicted range of stability. The intermediate-frequency wagging and bending vibrations have more contribution to electron-phonon coupling parameter than high-frequency stretching vibrations of H2 and H3. PMID:26964636 1. Multidimensional Chemical Modeling. III. Abundance and excitation of diatomic hydrides CERN Document Server Bruderer, Simon; Stäuber, P; Doty, Steven D 2010-01-01 The Herschel Space Observatory opens the sky for observations in the far infrared at high spectral and spatial resolution. A particular class of molecules will be directly observable; light diatomic hydrides and their ions (CH, OH, SH, NH, CH+, OH+, SH+, NH+). These simple constituents are important both for the chemical evolution of the region and as tracers of high-energy radiation. If outflows of a forming star erode cavities in the envelope, protostellar far UV (FUV; 6 100 K) for water ice to evaporate. If the cavity shape allows FUV radiation to penetrate this hot-core region, the abundance of FUV destroyed species (e.g. water) is decreased. In particular, diatomic hydrides and their ions CH$+, OH+ and NH+ are enhanced by many orders of magnitude in the outflow walls due to the combination of high gas temperatures and rapid photodissociation of more saturated species. The enhancement of these diatomic hydrides is sufficient for a detection using the HIFI and PACS instruments onboard Herschel. The effect...
2. Performance study of a hydrogen powered metal hydride actuator
Science.gov (United States)
Mainul Hossain Bhuiya, Md; Kim, Kwang J.
2016-04-01
A thermally driven hydrogen powered actuator integrating metal hydride hydrogen storage reactor, which is compact, noiseless, and able to generate smooth actuation, is presented in this article. To test the plausibility of a thermally driven actuator, a conventional piston type actuator was integrated with LaNi5 based hydrogen storage system. Copper encapsulation followed by compaction of particles into pellets, were adopted to improve overall thermal conductivity of the reactor. The operation of the actuator was thoroughly investigated for an array of operating temperature ranges. Temperature swing of the hydride reactor triggering smooth and noiseless actuation over several operating temperature ranges were monitored for quantification of actuator efficiency. Overall, the actuator generated smooth and consistent strokes during repeated cycles of operation. The efficiency of the actuator was found to be as high as 13.36% for operating a temperature range of 20 °C-50 °C. Stress-strain characteristics, actuation hysteresis etc were studied experimentally. Comparison of stress-strain characteristics of the proposed actuator with traditional actuators, artificial muscles and so on was made. The study suggests that design modification and use of high pressure hydride may enhance the performance and broaden the application horizon of the proposed actuator in future.
3. Effect of the hydrogen content and cooling velocity in the hydrides precipitation in α-zirconium
International Nuclear Information System (INIS)
Zirconium specimens containing 50-300 ppm hydrogen have been cooled from the hydrogen solution treatment temperature at different rates by furnace cooling, air cooling and oil quenching. Optical and electron microscopical investigations have revealed grain boundary Δ - hydrides in slowly cooled specimens. At higher cooling rates γ and Δ hydrides have been found precipitated both intergranularly and intragranularly. Grain boundary Δ hydrides have been also observed in oil quenched specimens with 300 ppm hydrogen. Quenched specimens have revealed Widmanstatten and parallel plate type hydride morphologies. (Author)
4. Development of new reactor fuel materials: hydrogenation properties of UThZr alloys and neutron irradiation effects on their hydrides
Science.gov (United States)
Yamamoto, Takuya; Suwamo, Hadi; Kayano, Hideo; Yamawaki, Michio
1997-08-01
Hydrogen absorption properties of four UThZr alloys with compositions of 2:1:6, 1:1:4, 1:2:6 and 1:4:10 in U:Th:Zr ratio were examined for developing a new UTh mixed hydride fuel. It was revealed by hydrogen absorption measurement that for all the specimens hydrogen capacities normalized by the sum of Th and Zr contents were similar to or higher than that of the UZrH 2 - x alloy, TRIGA fuel, at temperatures from 773 to 1073 K and under hydrogen pressures from 10 2 to 10 5 Pa. Regarding the microstructure, the alloy hydrides consisted of three phases; α-U, ZrH 2 - x and ThZr 2H 7 - x , which are finely and homogeneously mixed with each other probably because they were formed from one solid solution phase stable at high temperatures. In the case of Th-rich alloys the α-U was about 1 μm in diameter and dispersed in the bulk of ThZr 2 H 7 - x and ZrH 2 - x. Such microstructure is quite similar to that of UZrH 2 - x fuel. The hydrides irradiated to 7.4 × 10 23 n/m 2 in the reactor showed a high phase stability.
5. Reactivity patterns of transition metal hydrides and alkyls
Energy Technology Data Exchange (ETDEWEB)
Jones, W.D. II
1979-05-01
The complex PPN/sup +/ CpV(CO)/sub 3/H/sup -/ (Cp=eta/sup 5/-C/sub 5/H/sub 5/ and PPN = (Ph/sub 3/P)/sub 2/) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN/sup +/ CpV(CO)/sub 3/H/sup -/ reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN/sup +/(CpV(C)/sub 3/X)/sup -/ and in some cases the binuclear bridging hydride PPN/sup +/ (CpV(CO)/sub 3/)/sub 2/H/sup -/. The borohydride salt PPN/sup +/(CpV(CO)/sub 3/BH/sub 4/)/sup -/ has also been prepared. The reaction between CpV(CO)/sub 3/H/sup -/ and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO)/sub 3/H/sup -/. Sodium amalgam reduction of CpRh(CO)/sub 2/ or a mixture of CpRh(CO)/sub 2/ and CpCo(CO)/sub 2/ affords two new anions, PPN/sup +/ (Cp/sub 2/Rh/sub 3/(CO)/sub 4/)/sup -/ and PPN/sup +/(Cp/sub 2/RhCo(CO)/sub 2/)/sup -/. CpMo(CO)/sub 3/H reacts with CpMo(CO)/sub 3/R (R=CH/sub 3/,C/sub 2/H/sub 5/, CH/sub 2/C/sub 6/H/sub 5/) at 25 to 50/sup 0/C to produce aldehyde RCHO and the dimers (CpMo(CO)/sub 3/)/sub 2/ and (CpMo(CO)/sub 2/)/sub 2/. In general, CpV(CO)/sub 3/H/sup -/ appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO)/sub 3/H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO)/sub 3/H/sup -/ generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO)/sub 3/H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species.
6. Reactivity patterns of transition metal hydrides and alkyls
International Nuclear Information System (INIS)
The complex PPN+ CpV(CO)3H- (Cp=eta5-C5H5 and PPN = (Ph3P)2) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN+ CpV(CO)3H- reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN+[CpV(C)3X]- and in some cases the binuclear bridging hydride PPN+ [CpV(CO)3]2H-. The borohydride salt PPN+[CpV(CO)3BH4]- has also been prepared. The reaction between CpV(CO)3H- and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO)3H-. Sodium amalgam reduction of CpRh(CO)2 or a mixture of CpRh(CO)2 and CpCo(CO)2 affords two new anions, PPN+ [Cp2Rh3(CO)4]- and PPN+[Cp2RhCo(CO)2]-. CpMo(CO)3H reacts with CpMo(CO)3R (R=CH3,C2H5, CH2C6H5) at 25 to 500C to produce aldehyde RCHO and the dimers [CpMo(CO)3]2 and [CpMo(CO)2]2. In general, CpV(CO)3H- appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO)3H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO)3H- generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO)3H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species
7. Characterization of aluminum nanopowders after long-term storage
International Nuclear Information System (INIS)
Highlights: • The aluminum nanopowders produced by electrical explosion of wires after long-term storage (27 and 10 years) under natural conditions are characterized. • The phase composition and thermal stability of aluminum nanopowders after long-term storage are determined. • The surface chemical changes in the aged aluminum nanopowders are examined. • The high reactivity of aluminum nanopowder is due to the presence of the protective oxide–hydroxide layer on the particles surface. - Abstract: The characteristics of aluminum nanopowders obtained by electrical explosion of wires, passivated by air and stored for a long time under natural conditions are analyzed. The aluminum nanopowder produced in hydrogen had been stored for 27 years; the nanopowders produced in argon and nitrogen had been stored for 10 years. The powders were studied using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry (TG) and Fourier transform infrared spectrometry (FTIR). The influence of the obtaining conditions and storage period of nanopowders on their thermal stability under heating in air is shown. The aluminum nanopowders after long-term storage in air under ambient conditions are found to be extremely active
8. Determination of fracture strength of δ-zirconium hydrides embedded in zirconium matrix at high temperatures
Science.gov (United States)
Kubo, T.; Kobayashi, Y.; Uchikoshi, H.
2013-04-01
The fracture strength of δ-zirconium hydrides embedded in a zirconium matrix was determined at temperatures between 25 °C and 250 °C by ring tensile tests using Zircaloy-2 tubes. Essentially all of the present hydrides in the tubes were re-oriented in the radial direction by a temperature cycling treatment and then tensile stress was applied perpendicular to the hydrides to ensure that brittle fracture would occur at the hydrides. The hydrides failed in a brittle manner below 100 °C where-as the zirconium matrix itself underwent ductile fracture without hydride cracking at temperatures above 200 °C under plane stress condition. Brittle fracture of the hydrides continued to occur at temperatures up to 250 °C under plane strain condition, suggesting that the upper limit temperature for hydride fracture, Tupper, was raised by the triaxial stress state under the plane strain condition. The apparent fracture strength of the hydrides, σhydridef, was determined at temperatures below Tupper from the measured fracture strength of the tubes, making a correction for the compressive transformation stress in the hydrides. σhydridef was about 710 MPa at temperatures between 25 °C and 250 °C at both plane stress and plane strain conditions. The temperature dependency was very small in this temperature range. Tupper was almost equivalent to the cross-over temperature between σhydridef and the ultimate tensile strength (UTS), which suggests that, at temperatures above Tupper, the zirconium matrix would undergo ductile fracture before the stress in the hydride is raised above σhydridef, since UTS is smaller than σhydridef.
9. In situ generation of hydrogen from water by aluminum corrosion in solutions of sodium aluminate
Energy Technology Data Exchange (ETDEWEB)
Soler, Lluis; Candela, Angelica Maria; Munoz, Maria; Casado, Juan [Centre Grup de Tecniques de Separacio en Quimica (GTS), Unitat de Quimica Analitica, Departament de Quimica, Universitat Autonoma de Barcelona, Campus UAB s/n, 08193 Bellaterra, Barcelona, Catalonia (Spain); Macanas, Jorge [Laboratoire de Genie Chimique, UMR 5503 CNRS-INPT-UPS, Universite de Toulouse, Toulouse (France)
2009-07-01
A new process to obtain hydrogen from water using aluminum in sodium aluminate solutions is described and compared with results obtained in aqueous sodium hydroxide. This process consumes only water and aluminum, which are raw materials much cheaper than other compounds used for in situ hydrogen generation, such as hydrocarbons and chemical hydrides, respectively. As a consequence, our process could be an economically feasible alternative for hydrogen to supply fuel cells. Results showed an improvement of the maximum rates and yields of hydrogen production when NaAlO{sub 2} was used instead of NaOH in aqueous solutions. Yields of 100% have been reached using NaAlO{sub 2} concentrations higher than 0.65 M and first order kinetics at concentrations below 0.75 M has been confirmed. Two different heterogeneous kinetic models are verified for NaAlO{sub 2} aqueous solutions. The activation energy (E{sub a}) of the process with NaAlO{sub 2} is 71 kJ mol{sup -1}, confirming a control by a chemical step. A mechanism unifying the behavior of Al corrosion in NaOH and NaAlO{sub 2} solutions is presented. The application of this process could reduce costs in power sources based on fuel cells that nowadays use hydrides as raw material for hydrogen production. (author)
10. Reduced enthalpy of metal hydride formation for Mg-Ti nanocomposites produced by spark discharge generation.
Science.gov (United States)
Anastasopol, Anca; Pfeiffer, Tobias V; Middelkoop, Joost; Lafont, Ugo; Canales-Perez, Roger J; Schmidt-Ott, Andreas; Mulder, Fokko M; Eijt, Stephan W H
2013-05-29
Spark discharge generation was used to synthesize Mg-Ti nanocomposites consisting primarily of a metastable body-centered-cubic (bcc) alloy of Mg and Ti. The bcc Mg-Ti alloy transformed upon hydrogenation into the face-centered-cubic fluorite Mg1-yTiyHx phase with favorable hydrogen storage properties. Both metal and metal hydride nanocomposites showed a fractal-like porous morphology, with a primary particle size of 10-20 nm. The metal content of 70 atom % (at %) Mg and 30 at % Ti, consistently determined by XRD, TEM-EDS, and ICP-OES, was distributed uniformly across the as-prepared sample. Pressure-composition isotherms for the Mg-Ti-H nanocomposites revealed large differences in the thermodynamics relative to bulk MgH2, with a much less negative enthalpy of formation of the hydride as small as -45 ± 3 kJ/molH2 as deduced from van't Hoff plots. The plateau pressures of hydrogenation were substantially higher than those for bulk MgH2 in the low temperature range from 150 to 250 °C. The reaction entropy was simultaneously reduced to values down to 84 ± 5 J/K mol H2, following a linear relationship between the enthalpy and entropy. Plausible mechanisms for the modified thermodynamics are discussed, including the effect of lattice strains, the presence of interfaces and hydrogen vacancies, and the formation of excess free volume due to local deformations. These mechanisms all rely on the finely interdispersed nanocomposite character of the samples which is maintained by grain refinement.
11. [Electronic structure of helium and hydride complexes
International Nuclear Information System (INIS)
Research on the electronic structure of weakly bound helium and hydrogen species is described. The work grew from interest in a remarkable experimental observation at Los Alamos which shows that the helium generated from radioactive decay of liquid tritium remains in solution at concentrations which exceed the known solubility by much more than a factor of 100. The understanding of this supersolubility phenomenon is a challenging problem with significant implications for other condensed phase systems. In the hope of discovering the mechanism of the supersolubility, electronic structure calculations were carried out employing several methods to evaluate the binding energies of complexes of the form He(H+) (H2)/sub n/, with n = 2, 3, 4. For comparison, similar calculations were made for the complexes H2(H+) (H2)/sub n/. Also, the binding of the negative counter-ion species of the form (H-) (H2)/sub n/ was calculated. Although the calculations show that such complexes have sufficient binding energy to account for the enhanced solubility at the low temperature (20 K) of interest, major questions remain to be clarified. These include the mechanism for formation of the complexes, which may well involve excited, Rydberg-like states in solution. Another quite crucial question is how such weak complexes could persist in solution for months without displacement of the He by solvent molecules. Theoretical calculations focus on three topics: (1) Rydberg states; (2) condensed phase interactions; and (3) estimates of ionic conductivity in tritium solutions, as an aid to the interpretation of experiments now underway at Los Alamos
12. Metal hydride and pyrophoric fuel additives for dicyclopentadiene based hybrid propellants
Science.gov (United States)
Shark, Steven C.
13. Low activation R-tokamak with aluminum alloy
International Nuclear Information System (INIS)
An aluminum alloy system is considered as an alternative of the first phase design of the R-tokamak. The 1-D calculation showed that the radiation level outside the vacuum vessel could be reduced by a factor of 30 about half a month after a D-T shot, when the aluminum alloy system is adopted instead of a stainless steel system. The aluminum system has weak mechanical strength, is highly conductive, and shows overaging effect at a certain low temperature. Accordingly, it is necessary to overcome these points. The highly conductive aluminum case leads to considerable increase in power consumption. Various problems on the toroidal coils, the vacuum system, and the limiter were studied. The optimization of the device parameters was investigated. (Kato, T.)
14. New CeMgCo4 and Ce2MgCo9 compounds: Hydrogenation properties and crystal structure of hydrides
Science.gov (United States)
Denys, R. V.; Riabov, A. B.; Černý, R.; Koval'chuk, I. V.; Zavaliy, I. Yu.
2012-03-01
Two new ternary intermetallic compounds, CeMgCo4 (C15b pseudo-Laves phase, MgCu4Sn type) and Ce2MgCo9 (substitution derivative of PuNi3 type) were synthesized by mechanical alloying method. The structural and hydrogenation properties of these compounds were studied by X-ray diffraction and Pressure-Composition-Temperature measurements. Both compounds absorb hydrogen at room temperature and pressures below 10 MPa forming hydrides with maximum compositions CeMgCo4H6 and Ce2MgCo9H12. Single plateau behavior was observed in P-C isotherm during hydrogen absorption/desorption by Ce2MgCo9 alloy. The CeMgCo4-H2 system is characterized by the presence of two absorption/desorption plateaus corresponding to formation of β-CeMgCo4H4 and γ-CeMgCo4H6 hydride phases. The structure of β-hydride CeMgCo4H(D)4 was determined from X-ray and neutron powder diffraction data. In this structure initial cubic symmetry of CeMgCo4 is preserved and hydrogen atoms fill only one type of interstitial sites, triangular MgCo2 faces. These positions are occupied by 70% and form octahedron around Mg atom with Mg-D bond distances 1.84 Å.
15. Experiments on hadronic-atom x-ray intensities of hydrides and deuterides
Energy Technology Data Exchange (ETDEWEB)
Wiegand, C.E.; Lum, G.K.; Godfrey, G.L.
1977-04-01
Kaonic-atom x-ray intensities of elements Z = 3, 6, 8, 11, and 20 were significantly reduced when the elements were in hydride form. The ratios I (ZH/sub m/)/I (Z) have a noticeable Z dependence. Deuterides of C and O showed slightly less x-ray emission than their hydride counterparts.
16. Study on the Use of Hydride Fuel in High-Performance Light Water Reactor Concept
Directory of Open Access Journals (Sweden)
Haileyesus Tsige-Tamirat
2015-01-01
Full Text Available Hydride fuels have features which could make their use attractive in future advanced power reactors. The potential benefit of use of hydride fuel in HPLWR without introducing significant modification in the current core design concept of the high-performance light water reactor (HPLWR has been evaluated. Neutronics and thermal hydraulic analyses were performed for a single assembly model of HPLWR with oxide and hydride fuels. The hydride assembly shows higher moderation with softer neutron spectrum and slightly more uniform axial power distribution. It achieves a cycle length of 18 months with sufficient excess reactivity. At Beginning of Cycle the fuel temperature coefficient of the hydride assembly is higher whereas the moderator and void coefficients are lower. The thermal hydraulic results show that the achievable fuel temperature in the hydride assembly is well below the design limits. The potential benefits of the use of hydride fuel in the current design of the HPLWR with the achieved improvements in the core neutronics characteristics are not sufficient to justify the replacement of the oxide fuel. Therefore for a final evaluation of the use of hydride fuels in HPLWR concepts additional studies which include modification of subassembly and core layout designs are required.
17. Hydride precipitation and its influence on mechanical properties of notched and unnotched Zircaloy-4 plates
International Nuclear Information System (INIS)
The hydride formation and its influence on the mechanical performance of hydrided Zircaloy-4 plates containing different hydrogen contents were studied at room temperature. For the unnotched plate samples with the hydrogen contents ranging from 25 to 850 wt. ppm, the hydrides exerted an insignificant effect on the tensile strength, while the ductility was severely degraded with increasing hydrogen content. The fracture mode and degree of embrittlement were strongly related to the hydrogen content. When the hydrogen content reached a level of 850 wt. ppm, the plate exhibited negligible ductility, resulting in almost completely brittle behavior. For the hydrided notched plate, the tensile stress concentration associated with the notch tip facilitated the hydride accumulation at the region near the notch tip and the premature crack propagation through the hydride fracture during hydriding. The final brittle through-thickness failure for this notched sample was mainly attributed to the formation of a continuous hydride network on the thickness section and the obtained very high hydrogen concentration (estimated to be 1965 wt. ppm)
18. 21 CFR 73.1645 - Aluminum powder.
Science.gov (United States)
2010-04-01
... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....
19. Uranium-zirconium hydride TRIGA-LEU fuel
International Nuclear Information System (INIS)
The development and testing of TRIGA-LEU fuel with up to 45 wt-% U is described. Topics that are discussed include properties of hydride fuels, the prompt negative temperature coefficient, pulse heating tests, fission product retention, and the limiting design basis parameter and values. General specifications for Er-U-ZrH TRIGA-LEU fuel with 8.5 to 45 wt-% U and an outline of the inspections during manufacture of the fuel are also included. (author). 8 figs, 1 tab
20. Hydride Ions, HCO+ and Ionizing Irradiation in Star Forming Region
Science.gov (United States)
Benz, Arnold O.; Bruderer, Simon; van Dishoeck, Ewine
2016-06-01
Hydrides are fundamental precursor molecules in cosmic chemistry and many hydride ions have become observable in high quality for the first time thanks to the Herschel Space Observatory. Ionized hydrides, such as CH+ and OH+ and also HCO+ affect the chemistry of molecules such as water. They also provide complementary information on irradiation by far UV (FUV) or X-rays and gas temperature.We explore hydrides of the most abundant heavier elements in an observational survey covering star forming regions with different mass and evolutionary state. Twelve YSOs were observed with HIFI on Herschel in 6 spectral settings providing fully velocity-resolved line profiles. The YSOs include objects of low (Class 0 and I), intermediate, and high mass, with luminosities ranging from 4 Ls to 2 105 Ls.The targeted lines of CH+, OH+, H2O+, and C+ are detected mostly in blue-shifted absorption. H3O+ and SH+ are detected in emission and only toward some high-mass objects. For the low-mass YSOs the column density ratios of CH+/OH+ can be reproduced by simple chemical models implying an FUV flux of 2 – 400 times the ISRF at the location of the molecules. In two high-mass objects, the UV flux is 20 – 200 times the ISRF derived from absorption lines, and 300 – 600 ISRF using emission lines. Upper limits for the X-ray luminosity can be derived from H3O+ observations for some low-mass objects.If the FUV flux required for low-mass objects originates at the central protostar, a substantial FUV luminosity, up to 1.5 Ls, is required. For high-mass regions, the FUV flux required to produce the observed molecular ratios is smaller than the unattenuated flux expected from the central object(s) at the Herschel beam radius. This is consistent with an FUV flux reduced by circumstellar extinction or by bloating of the protostar.The ion molecules are proposed to form in FUV irradiated cavity walls that are shocked by the disk wind. The shock region is turbulent, broadening the lines to some 1
1. Research in Nickel/Metal Hydride Batteries 2016
Directory of Open Access Journals (Sweden)
Kwo-Hsiung Young
2016-10-01
Full Text Available Nineteen papers focusing on recent research investigations in the field of nickel/metal hydride (Ni/MH batteries have been selected for this Special Issue of Batteries. These papers summarize the joint efforts in Ni/MH battery research from BASF, Wayne State University, the National Institute of Standards and Technology, Michigan State University, and FDK during 2015–2016 through reviews of basic operational concepts, previous academic publications, issued US Patent and filed Japan Patent Applications, descriptions of current research results in advanced components and cell constructions, and projections of future works.
2. The calculated rovibronic spectrum of scandium hydride, ScH
CERN Document Server
Lodi, Lorenzo; Tennyson\\, Jonathan
2015-01-01
The electronic structure of six low-lying electronic states of scandium hydride, $X\\,{}^{1}\\Sigma^+$, $a\\,{}^{3}\\Delta$, $b\\,{}^{3}\\Pi$, $A\\,{}^{1}\\Delta$ $c\\,{}^{3}\\Sigma^+$, and $B\\,{}^{1}\\Pi$, is studied using multi-reference configuration interaction as a function of bond length. Diagonal and off-diagonal dipole moment, spin-orbit coupling and electronic angular momentum curves are also computed. The results are benchmarked against experimental measurements and calculations on atomic scandium. The resulting curves are used to compute a line list of molecular ro-vibronic transitions for $^{45}$ScH.
3. Alkyl and Hydride-Olefin Complexes of Niobocene
NARCIS (Netherlands)
Klazinga, A.H.; Teuben, J.H.
1980-01-01
Reactions of Cp2NbCl2 with RMgCl (R = n-C3H7, i-C3H7, n-C4H9, s-C4H9 and n-C5H11) give niobocene hydride olefin complexes Cp2Nb(H)L (L = C3H6, C4H8 and C5H10). The last step of the reaction probably proceeds via a stereospecific β-H elimination from the monoalkyl species Cp2NbR. Decomposition of n-a
4. Equilibrium composition for the reaction of plutonium hydride with air
Institute of Scientific and Technical Information of China (English)
2002-01-01
There are six independent constituents with 4 chemical elements, i.e. PuH2.7(s), PuN(s), Pu2O3(s), N2, O2 and H2, therefore , the system described involves of 2 independent reactions ,both those of the experimental, which indicates that the chemical equilibrium is nearly completely approached. Therefore, it is believed that the reaction rate of plutonium hydride with air is extremely rapid. The present paper has briefly discussed the simultaneous reactions and its thermodynamic coupling effect.
5. Comparison between different reactions of group IV hydride with H
Institute of Scientific and Technical Information of China (English)
ZHANG; Shaolong; ZHANG; Xuqiang; ZHANG; Qinggang; ZHANG; Yici
2006-01-01
The four-dimensional time-dependent quantum dynamics calculations for reactions of group IV hydride with H are carried out by employing the semirigid vibrating rotor target model and the time-dependent wave packet method. The reaction possibility, cross section and rate constants for reactions (H+SiH4 and H+GeH4) in different initial vibrational and rotational states are obtained. The common feature for such kind of reaction process is summarized. The theoretical result is consistent with available measurement, which indicates the credibility of this theory and the potential energy surface.
6. Another Look at the Mechanisms of Hydride Transfer Enzymes with Quantum and Classical Transition Path Sampling.
Science.gov (United States)
Dzierlenga, Michael W; Antoniou, Dimitri; Schwartz, Steven D
2015-04-01
The mechanisms involved in enzymatic hydride transfer have been studied for years, but questions remain due, in part, to the difficulty of probing the effects of protein motion and hydrogen tunneling. In this study, we use transition path sampling (TPS) with normal mode centroid molecular dynamics (CMD) to calculate the barrier to hydride transfer in yeast alcohol dehydrogenase (YADH) and human heart lactate dehydrogenase (LDH). Calculation of the work applied to the hydride allowed for observation of the change in barrier height upon inclusion of quantum dynamics. Similar calculations were performed using deuterium as the transferring particle in order to approximate kinetic isotope effects (KIEs). The change in barrier height in YADH is indicative of a zero-point energy (ZPE) contribution and is evidence that catalysis occurs via a protein compression that mediates a near-barrierless hydride transfer. Calculation of the KIE using the difference in barrier height between the hydride and deuteride agreed well with experimental results.
7. Hydrogenation reaction characteristics and properties of its hydrides for magnetic regenerative material HoCu2
Institute of Scientific and Technical Information of China (English)
金滔; 吴梦茜; 黄迦乐; 汤珂; 陈立新
2016-01-01
The hydrogenation reaction characteristics and the properties of its hydrides for the magnetic regenerative material HoCu2 (CeCu2-type) of a cryocooler were investigated. The XRD testing reveals that the hydrides of HoCu2 were a mixture of Cu, unknown hydride I, and unknown hydride II. Based on the PCT (pressure−concentration−temperature) curves under different reaction temperatures, the relationships among reaction temperature, equilibrium pressure, and maximum hydrogen absorption capacity were analyzed and discussed. The enthalpy changeΔH and entropy changeΔS as a result of the whole hydrogenation process were also calculated from the PCT curves. The magnetization and volumetric specific heat capacity of the hydride were also measured by SQUID magnetometer and PPMS, respectively.
8. Mobility and chemical bond of hydrogen in titanium and palladium hydrides
International Nuclear Information System (INIS)
The probabilities for π- meson capture by hydrogen are measured at 25, 155 and 200 deg C in TiHsub(1.65) hydride and at 25, -120 and -196 deg C in PdHsub(0.67) hydride. An analysis of the results obtained shows that within the accuracy of the measurements (approximately 10%) a sharp (up to 1012) change in the mobility of hydrogen in the hydrides induced by temperature changes within the ranges indicated does not noticeably affect the probabilities for π- meson capture by bound hydrogen, i.e. does not lead to appreciable changes in the Me-H bond. A comparison of the capture probabilities for palladium hydride and hydrides of neighboring transition metals shows that there are no pronounced anomalies in the Pd-H bond
9. Gas atomization processing of tin and silicon modified LaNi{sub 5} for nickel-metal hydride battery applications
Energy Technology Data Exchange (ETDEWEB)
Ting, J.
1999-02-12
Numerous researchers have studied the relevant material properties of so-called AB{sub 5} alloys for battery applications. These studies involved LaNi{sub 5} substituted alloys which were prepared using conventional cast and crush alloying techniques. While valuable to the understanding of metal hydride effects, the previous work nearly ignored the potential for alternative direct powder production methods, like high pressure gas atomization (HPGA). Thus, there is a need to understand the relationship between gas atomization processes, powder particle solidification phases, and hydrogen absorption properties of ultra fine (< 25 {micro}m) atomized powders with high surface area for enhanced battery performance. Concurrently, development of a gas atomization nozzle that is more efficient than all current designs is needed to increase the yield of ultrafine AB{sub 5} alloy powder for further processing advantage. Gas atomization processing of the AB{sub 5} alloys was demonstrated to be effective in producing ultrafine spherical powders that were resilient to hydrogen cycling for the benefit of improving corrosion resistance in battery application. These ultrafine powders benefited from the rapid solidification process by having refined solute segregation in the microstructure of the gas atomized powders which enabled a rapid anneal treatment of the powders. The author has demonstrated the ability to produce high yields of ultrafine powder efficiently and cost effectively, using the new HPGA-III technology. Thus, the potential benefits of processing AB{sub 5} alloys using the new HPGA technology could reduce manufacturing cost of nickel-metal hydride powder. In the near future, the manufacture of AB{sub 5} alloy powders could become a continuous and rapid production process. The economic benefit of an improved AB{sub 5} production process may thereby encourage the use of nickel-metal hydride rechargeable batteries in electrical vehicle applications in the foreseeable
10. Formation of alloys in Ti-V system in hydride cycle and synthesis of their hydrides in self-propagating high-temperature synthesis regime
Energy Technology Data Exchange (ETDEWEB)
Aleksanyan, A.G., E-mail: a.g.aleks_yan@mail.ru [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia); Dolukhanyan, S.K. [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia); Shekhtman, V.Sh. [Institute of Solid State Physics, RAS, Chernogolovka, Moscow District 142432 (Russian Federation); Huot, J., E-mail: jacques_huot@uqtr.ca [Institut de recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres (Canada); Ter-Galstyan, O.P.; Mnatsakanyan, N.L. [A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, 5/2 P.Sevak Str., Yerevan 0014 (Armenia)
2011-09-15
Research highlights: > We synthesize Ti-V alloys by new 'hydride cycle' method. Structural characteristics of formed alloys we investigate by X-ray diffraction. > We show that the alloys contain mainly BCC crystal structure. > We investigate the interaction of the synthesized alloys with hydrogen in combustion regime. > We study the properties of hydrides by X-ray, DTA and DSC analyses. - Abstract: In the present work, the possibility of formation of titanium and vanadium based alloys of BCC structure using hydride cycle was investigated. The mechanism of formation of alloys in Ti-V system from the powders of hydrides TiH{sub 2} and VH{sub 0.9} (or of V) by compaction followed by dehydrogenation was studied. Then, the interaction of the synthesized alloys with hydrogen in combustion regime (self-propagating high-temperature synthesis, SHS) resulting in hydrides of these alloys was investigated. DTA and DSC analyses of some alloys and their hydrides were performed and their thermal characteristics were measured.
11. Precipitate evolution in friction stir welding of 2219-T6 aluminum alloys
International Nuclear Information System (INIS)
Precipitate evolution in friction stir welding of 2219-T6 aluminum alloys was characterized by transmission electron microscopy. In the weld nugget zone and the thermo-mechanically affected zone some metastable precipitates overaged to equilibrium phase while others solutionized into the aluminum solid solution. In the heat-affected zone the precipitates coarsened.
12. Electrochemical and metallurgical characterization of ZrCr{sub 1-x}NiMo{sub x} AB{sub 2} metal hydride alloys
Energy Technology Data Exchange (ETDEWEB)
Erika, Teliz [Universidad de la República, Facultad de Ciencias, Laboratorio de Electroquímica Fundamental, Núcleo Interdisciplinario Ingeniería Electroquímica, Igua 4225, CP 11400 Montevideo (Uruguay); Ricardo, Faccio [Universidad de la República, Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Centro NanoMat, Polo Tecnológico de Pando, Espacio Interdisciplinario, Facultad de Química, Montevideo (Uruguay); Fabricio, Ruiz [Consejo Nacional de Investigaciones Científicas y Técnicas , CONICET, Av. Rivadavia 1917, C1033AAJ Ciudad de Buenos Aires (Argentina); Centro Atómico Bariloche , Comisión Nacional de Energía Atómica (CAB-CNEA), Av. Bustillo 9500, CP 8400 S.C. de Bariloche, RN (Argentina); Fernando, Zinola [Universidad de la República, Facultad de Ciencias, Laboratorio de Electroquímica Fundamental, Núcleo Interdisciplinario Ingeniería Electroquímica, Igua 4225, CP 11400 Montevideo (Uruguay); and others
2015-11-15
The effects of partial replacement of chromium by molybdenum was studied on the structure and electrochemical kinetic properties of ZrCr{sub 1-x}NiMo{sub x}(x = 0.0, 0.3 and 0.6) metal hydride alloys. The arc-melting prepared alloys were metallurgically characterized by X-ray diffraction and energy dispersive spectroscopy microanalysis, which showed AB{sub 2} (with hexagonal C14 structure) and Zr{sub x}Ni{sub y} (Zr{sub 7}Ni{sub 10}, Zr{sub 9}Ni{sub 11}) phases. After a partial substitution of chromium by molybdenum, secondary phases monotonically increase with the C14 unit cell volume indicating that most of molybdenum atoms locate in the B-site. The alloys were electrochemically characterized using charge/discharge cycling, electrochemical impedance spectroscopy and rate capability experiments that allowed the determination of hydriding reaction kinetic parameters. The presence of molybdenum produces a positive effect for hydrogen diffusion in the alloy lattice, and ZrCr{sub 0.7}NiMo{sub 0.3} alloy depicts the better kinetics associated with a fast activation, lower charge transfer resistance and the best high rate discharge behavior. This fact would be related to a lower diffusion time constant and a bigger value of the product between exchange density current and surface active area. There is a trade-off in the amounts of secondary phase and Laves phases in order to improve the kinetic performance. - Highlights: • Metallurgical characterization evidences the presence of Zr{sub x}Ni{sub y} and C14 phases. • The partial replacement of Cr by Mo promotes the segregation of Zr{sub x}Ni{sub y} phase. • The incorporation of molybdenum improves the kinetics for the hydriding process. • Mo produces a decrease in the diffusion time constant.
13. Invisible Display in Aluminum
DEFF Research Database (Denmark)
Prichystal, Jan Phuklin; Hansen, Hans Nørgaard; Bladt, Henrik Henriksen
2005-01-01
Bang & Olufsen a/s has been working with ideas for invisible integration of displays in metal surfaces. Invisible integration of information displays traditionally has been possible by placing displays behind transparent or semitransparent materials such as plastic or glass. The wish...... for an integrated display in a metal surface is often ruled by design and functionality of a product. The integration of displays in metal surfaces requires metal removal in order to clear the area of the display to some extent. The idea behind an invisible display in Aluminum concerns the processing of a metal...
14. Interfacial characterization of resistance spot welded joint of steel and aluminum alloy
Institute of Scientific and Technical Information of China (English)
Zhang Weihua; Sun Daqian; Yin Shiqiang; Han Lijun; Qiu Xiaoming; Chen Qinglei
2010-01-01
The dissimilar material resistance spot welding of galvanized high strength steel and aluminum alloy had been conducted. The welded joint exhibited a thin reaction layer composed of Fe2Al5 and Fe4Al13 phases at steel/aluminum interface. The welded joint presented a tensile shear load of 3.3 kN with an aluminum alloy nugget diameter of 5.7 ram. The interfucial failure mode was observed for the tensile shear specimen and fracture occurred at reaction layer and aluminum alloy fusion zone beside the interface. The reaction layer with compounds was the main reason for reduction of the welded joint mechanical property.
15. Reactions of ruthenium hydrides with ethyl-vinyl sulfide.
Science.gov (United States)
Dahcheh, Fatme; Stephan, Douglas W
2014-03-01
The Ru-hydride precursors (Im(OMe)2)(PPh3)2RuHCl () and (Me2Im(OMe)2)(PPh3)2RuHCl () reacted with ethyl-vinyl-sulfide to give ((MeOCH2CH2)C3H2N2(CH2CH(OMe))RuCl(PPh3)2 () and ((MeOCH2CH2)C3Me2N2(CH2CH(OMe))RuCl(PPh3)2 (), respectively. Dissolution of () in C6D6 prompts formation of ((MeOCH2CH2)C5H6N2(CHCH)RuCl(PPh3)2 (). The analogous reactions of the bis-carbene Ru-hydride precursors (Im(OMe)2)(IMes)(PPh3)RuHCl (), (Im(OMe)2)(SIMes)(PPh3)RuHCl () and (Im(OMe)2)(IMes-Cl2)(PPh3)RuHCl () gave ((MeOCH2CH2)C3H2N2(CHCH)RuCl(PPh3)(NHC) (NHC = IMes (), SIMes (), IMes-Cl2 (), respectively. The formation of compounds () and () is thought to go through an initial insertion of the vinyl-fragment into the Ru-H prompting subsequent C-H activation and loss of diethyl sulfide. This yields () and (), while subsequent loss of methanol yields () and (-). PMID:24441082
16. Thermodynamic Calculation on the Formation of Titanium Hydride
Institute of Scientific and Technical Information of China (English)
Jing-wei Zhao; Hua Ding; Xue-feng Tian; Wen-juan Zhao; Hong-liang Hou
2008-01-01
A modified Miedema model, using interrelationship among the basic properties of elements Ti and H, is employed to calculate the standard enthalpy of formation of titanium hydride TiHx (1≤x≤2). Based on Debye theories of solid thermal capacity, the vibrational entropy, as well as electronic entropy, is acquired by quantum mechanics and statistic thermodynamics methods, and a new approach is presented to calculate the standard entropy of formation of Till2. The values of standard enthalpy of formation of TiHx decrease linearly with increase of x. The calculated results of standard enthalpy, entropy, and free energy of forma- tion of Till2 at 298.16 K are -142.39 kJ/mol, -143.0 J/(mol-K) and -99.75 k J/tool, respectively, which is consistent with the previously-reported data obtained by either experimental or theoretical calculation methods. The results show that the thermodynamic model for titanium hydride is reasonable.
17. Measurement of nuclear fuel pin hydriding utilizing epithermal neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Miller, W.H. [Univ. of Missouri, Columbia, MO (United States); Farkas, D.M.; Lutz, D.R. [General Electric Co., Pleasanton, CA (United States)
1996-12-31
The measurement of hydrogen or zirconium hydriding in fuel cladding has long been of interest to the nuclear power industry. The detection of this hydrogen currently requires either destructive analysis (with sensitivities down to 1 {mu}g/g) or nondestructive thermal neutron radiography (with sensitivities on the order of a few weight percent). The detection of hydrogen in metals can also be determined by measuring the slowing down of neutrons as they collide and rapidly lose energy via scattering with hydrogen. This phenomenon is the basis for the {open_quotes}notched neutron spectrum{close_quotes} technique, also referred to as the Hysen method. This technique has been improved with the {open_quotes}modified{close_quotes} notched neutron spectrum technique that has demonstrated detection of hydrogen below 1 {mu}g/g in steel. The technique is nondestructive and can be used on radioactive materials. It is proposed that this technique be applied to the measurement of hydriding in zirconium fuel pins. This paper summarizes a method for such measurements.
18. Method of generating hydrogen-storing hydride complexes
Science.gov (United States)
Srinivasan, Sesha S; Niemann, Michael U; Goswami, D. Yogi; Stefanakos, Elias K
2013-05-14
A ternary hydrogen storage system having a constant stoichiometric molar ratio of LiNH.sub.2:MgH.sub.2:LiBH.sub.4 of 2:1:1. It was found that the incorporation of MgH.sub.2 particles of approximately 10 nm to 20 nm exhibit a lower initial hydrogen release temperature of 150.degree. C. Furthermore, it is observed that the particle size of LiBNH quaternary hydride has a significant effect on the hydrogen sorption concentration with an optimum size of 28 nm. The as-synthesized hydrides exhibit two main hydrogen release temperatures, one around 160.degree. C. and the other around 300.degree. C., with the main hydrogen release temperature reduced from 310.degree. C. to 270.degree. C., while hydrogen is first reversibly released at temperatures as low as 150.degree. C. with a total hydrogen capacity of 6 wt. % to 8 wt. %. Detailed thermal, capacity, structural and microstructural properties have been demonstrated and correlated with the activation energies of these materials.
19. Superconductive "sodalite"-like clathrate calcium hydride at high pressures
CERN Document Server
Wang, Hui; Tanaka, Kaori; Iitaka, Toshiaki; Ma, Yanming
2012-01-01
Hydrogen-rich compounds hold promise as high-temperature superconductors under high pressures. Recent theoretical hydride structures on achieving high-pressure superconductivity are composed mainly of H2 fragments. Through a systematic investigation of Ca hydrides with different hydrogen contents using particle-swam optimization structural search, we show that in the stoichiometry CaH6 a body-centred cubic structure with hydrogen that forms unusual "sodalite" cages containing enclathrated Ca stabilizes above pressure 150 GPa. The stability of this structure is derived from the acceptance by two H2 of electrons donated by Ca forming a "H4" unit as the building block in the construction of the 3-dimensional sodalite cage. This unique structure has a partial occupation of the degenerated orbitals at the zone centre. The resultant dynamic Jahn-Teller effect helps to enhance electron-phonon coupling and leads to superconductivity of CaH6. A superconducting critical temperature (Tc) of 220-235 K at 150 GPa obtained...
20. Neurofibrillary pathology and aluminum in Alzheimer's disease
OpenAIRE
Shin, R. W.; Lee, V. M. Y; Trojanowski, J Q
1995-01-01
Since the first reports of aluminum-induced neurofibrillary degeneration in experimental animals, extensive studies have been performed to clarify the role played by aluminum in the pathogenesis of Alzheimer's disease (AD). Additional evidence implicating aluminum in AD includes elevated levels of aluminum in the AD brain, epidemiological data linking aluminum exposure to AD, and interactions between aluminum and protein components in the pathological lesions o...
1. Infiltration of molten aluminum in aluminum-nickel powder preform
International Nuclear Information System (INIS)
It has been shown by the present author that when molten aluminum comes in contact with nickel, an exothermic reaction is initiated and both stiochiometric and non-stiochiometric phases form at the interface. For nickel powders, such reaction is expected to be much faster due to high surface area to volume ratio of the fine particles. Infiltration of molten metals in ceramics powder preforms has long been used to fabricate near or net-shaped Metal Matrix Composite components. For metallic preforms however, it is important to see if the exothermic reaction compromises the infiltration of the molten metal constituent, i.e. defective components. The current project studied the fabrication of near net-shaped Intermetallic Matrix Composites, (IMC) via molten metal infiltration and subsequent reaction with the metal powder preform. X-ray diffraction (XRD), Optical and SEM microscopes were used to characterize the infiltration, reaction and the resulted microstructure. It is expected that the molten metal temperature, holding time within the molten metal, the infiltration pressure, i.e. metallostatic pressure and the preform compaction pressure are all important parameters to be considered carefully to achieve sound components. The current report examined the feasibility of such fabrication technique and the resultant microstructure. (author)
2. The Development of an Innovative Vertical Floatation Melter and Scrap Dryer for Use in the Aluminum Processing Industry
Energy Technology Data Exchange (ETDEWEB)
Robert De Saro
2004-08-24
The project aimed at the development of a Vertical Floatation melter, for application to the aluminum industry. This is intended to improve both the energy efficiency and environmental performance of aluminum melting furnaces. Phase I of this project dealt primarily with the initial research effort. Phase II, dealt with pilot-scale testing.
3. Aluminum Nanoholes for Optical Biosensing
Directory of Open Access Journals (Sweden)
Carlos Angulo Barrios
2015-07-01
Full Text Available Sub-wavelength diameter holes in thin metal layers can exhibit remarkable optical features that make them highly suitable for (biosensing applications. Either as efficient light scattering centers for surface plasmon excitation or metal-clad optical waveguides, they are able to form strongly localized optical fields that can effectively interact with biomolecules and/or nanoparticles on the nanoscale. As the metal of choice, aluminum exhibits good optical and electrical properties, is easy to manufacture and process and, unlike gold and silver, its low cost makes it very promising for commercial applications. However, aluminum has been scarcely used for biosensing purposes due to corrosion and pitting issues. In this short review, we show our recent achievements on aluminum nanohole platforms for (biosensing. These include a method to circumvent aluminum degradation—which has been successfully applied to the demonstration of aluminum nanohole array (NHA immunosensors based on both, glass and polycarbonate compact discs supports—the use of aluminum nanoholes operating as optical waveguides for synthesizing submicron-sized molecularly imprinted polymers by local photopolymerization, and a technique for fabricating transferable aluminum NHAs onto flexible pressure-sensitive adhesive tapes, which could facilitate the development of a wearable technology based on aluminum NHAs.
4. Effect of Rare Earth Element Ce on Microstructure and Properties of Aluminum Rod for Electrical Purpose
Institute of Scientific and Technical Information of China (English)
Li Pengfei; Wang Yunli; Gao Xizhu; Wang Zaiyun
2004-01-01
The effect of rare earth element Ce on microstructure, electrical conductivity and mechanical properties was studied.Using optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffractometer, the microstructure and phase composition of aluminum rod for electrical purpose were measured and analyzed.The results indicate that rare earth element Ce can considerably refine grain size of aluminum rod for electrical purpose,improve the regular distribution pattern of the impurity, such as silicon and iron which present in the aluminum matrix,form stable metal compound with pernicious impurity.This metal compound precipitates on the crystal boundary.As a result, the solid solubility of impurity in aluminum reduce, and the electrical conductivity of aluminum rod for electrical purpose is improved.It is found that the mechanical properties of aluminum rod for electrical purpose are improved by rare earth element in certain range of RE addition.
5. Modeling the Shock Ignition of a Copper Oxide Aluminum Thermite
Science.gov (United States)
Lee, Kibaek; Stewart, D. Scott; Clemenson, Michael; Glumac, Nick; Murzyn, Christopher
2015-06-01
An experimental `striker confinement'' shock compression test was developed in the Glumac-group at the University of Illinois to study ignition and reaction in composite reactive materials. These include thermitic and intermetallic reactive powders. The test places a sample of materials such as a thermite mixture of copper oxide and aluminum powders that are initially compressed to about 80 percent full density. Two RP-80 detonators simultaneously push steel bars into reactive material and the resulting compression causes shock compaction of the material and rapid heating. At that point one observes significant reaction and propagation of fronts. But the fronts are peculiar in that they are comprised of reactive events that can be traced to the reaction/diffusion of the initially separated reactants of copper oxide and aluminum that react at their mutual interfaces that nominally make copper liquid and aluminum oxide products. We discuss our model of the shock ignition of the copper oxide aluminum thermite in the context of the striker experiment and how a Gibbs formulation model, that includes multi-components for liquid and solid phases of aluminum, copper oxide, copper and aluminum oxide can predict the events observed at the particle scale in the experiments. Supported by HDTRA1-10-1-0020 (DTRA), N000014-12-1-0555 (ONR).
6. Main Group Lewis Acid-Mediated Transformations of Transition-Metal Hydride Complexes.
Science.gov (United States)
Maity, Ayan; Teets, Thomas S
2016-08-10
This Review highlights stoichiometric reactions and elementary steps of catalytic reactions involving cooperative participation of transition-metal hydrides and main group Lewis acids. Included are reactions where the transition-metal hydride acts as a reactant as well as transformations that form the metal hydride as a product. This Review is divided by reaction type, illustrating the diverse roles that Lewis acids can play in mediating transformations involving transition-metal hydrides as either reactants or products. We begin with a discussion of reactions where metal hydrides form direct adducts with Lewis acids, elaborating the structure and dynamics of the products of these reactions. The bulk of this Review focuses on reactions where the transition metal and Lewis acid act in cooperation, and includes sections on carbonyl reduction, H2 activation, and hydride elimination reactions, all of which can be promoted by Lewis acids. Also included is a section on Lewis acid-base secondary coordination sphere interactions, which can influence the reactivity of hydrides. Work from the past 50 years is included, but the majority of this Review focuses on research from the past decade, with the intent of showcasing the rapid emergence of this field and the potential for further development into the future. PMID:27164024
7. Hualu Aluminum Will Construct Large Coal-Power-Aluminum Aluminum Processing Industrial Chain
Institute of Scientific and Technical Information of China (English)
2015-01-01
The reporter learned from relevant departments of Baiyin City that in order to further push forward industrial upgrading,fulfill expansion and consolidation of the enterprise,Gansu Hualu Aluminum Co.,Ltd(Hualu Aluminum)will implement Out-Of-City-Into-Park project,
8. Aluminum Zintl anion moieties within sodium aluminum clusters
Energy Technology Data Exchange (ETDEWEB)
Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Ganteför, Gerd; Bowen, Kit H., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Schnöckel, Hansgeorg [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Eichhorn, Bryan W. [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States); Lee, Mal-Soon; Jena, P. [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Kandalam, Anil K., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Physics, West Chester University of Pennsylvania, West Chester, Pennsylvania 19383 (United States); Kiran, Boggavarapu, E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)
2014-02-07
Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium–aluminum cluster anions, Na{sub m}Al{sub n}{sup −}, were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams.
9. Generalized computational model for high-pressure metal hydrides with variable thermal properties
DEFF Research Database (Denmark)
Mazzucco, Andrea; Rokni, Masoud
2015-01-01
This study considers a detailed 1D fueling model applied to a metal hydride system, with Ti1.1CrMn as the absorbing alloy, to predict the weight fraction of the absorbed hydrogen and the solid bed temperature. Dependencies of thermal conductivity and specific heat capacity upon pressure...... and hydrogen content, respectively, are accounted for by interpolating experimental data. The effect of variable parameters on the critical metal hydride thickness is investigated and compared to results obtained from a constant-parameter analysis. Finally, the discrepancy in the metal hydride thickness value...
10. Rapid Microwave Synthesis, Characterization and Reactivity of Lithium Nitride Hydride, Li4NH
OpenAIRE
Nuria Tapia-Ruiz; Natalie Sorbie; Nicolas Vaché; Hoang, Tuan K. A.; Gregory, Duncan H.
2013-01-01
Lithium nitride hydride, Li4NH, was synthesised from lithium nitride and lithium hydride over minute timescales, using microwave synthesis methods in the solid state for the first time. The structure of the microwave-synthesised powders was confirmed by powder X-ray diffraction [tetragonal space group I41/a; a = 4.8864(1) Å, c = 9.9183(2) Å] and the nitride hydride reacts with moist air under ambient conditions to produce lithium hydroxide and subsequently lithium carbonate. Li4NH undergoes n...
11. Solid hydrides as hydrogen storage reservoirs; Hidruros solidos como acumuladores de hidrogeno
Energy Technology Data Exchange (ETDEWEB)
Fernandez, A.; Sanchez, C.; Friedrichs, O.; Ares, J. R.; Leardini, F.; Bodega, J.; Fernandez, J. F.
2010-07-01
Metal hydrides as hydrogen storage materials are briefly reviewed in this paper. Fundamental properties of metal-hydrogen (gas) system such as Pressure-Composition-Temperature (P-C-T) characteristics are discussed on the light of the metal-hydride thermodynamics. Attention is specially paid to light metal hydrides which might have application in the car and transport sector. The pros and cons of MgH{sub 2} as a light material are outlined. Researches in course oriented to improve the behaviour of MgH{sub 2} are presented. Finally, other very promising alternative materials such as Al compounds (alanates) or borohydrides as light hydrogen accumulators are also considered. (Author)
12. Thermal decomposition kinetics of titanium hydride and Al alloy melt foaming process
Institute of Scientific and Technical Information of China (English)
YANG; Donghui; HE; Deping; YANG; Shangrun
2004-01-01
A temperature programmed decomposition (TPD) apparatus with metal tube structure, in which Ar is used as the carrier gas, is established and the TPD spectrum of titanium hydride is acquired. Using consulting table method (CTM), spectrum superposition method (SSM) and differential spectrum technique, TPD spectrum of titanium hydride is separated and a set of thermal decomposition kinetics equations are acquired. According to these equations, the relationship between decomposition quantity and time for titanium hydride at the temperature of 940 K is obtained and the result well coincides with the Al alloy melt foaming process.
13. Proton beam production by a laser ion source with hydride target
Energy Technology Data Exchange (ETDEWEB)
Okamura, M., E-mail: okamura@bnl.gov [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Stifler, C. [Engineering Physics Systems Department, Providence College, Providence, Rhode Island 02918 (United States); Palm, K. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States); Steski, D.; Kanesue, T. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa (Japan); Kumaki, M. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Research Institute for Science and Engineering, Waseda University, Tokyo (Japan)
2016-02-15
We studied proton beam production from a laser ion source using hydrogen rich target materials. In general, gas based species are not suitable for laser ion sources since formation of a dense laser target is difficult. In order to achieve reliable operation, we tested hydride targets using a sub nanosecond Q-switched Nd-YAG laser, which may help suppress target material consumption. We detected enough yields of protons from a titanium hydride target without degradation of beam current during the experiment. The combination of a sub nanosecond laser and compressed hydride target may provide stable proton beam.
14. Analytical control of production of As, P, Si, B hydrides and the mixtures on their basis
International Nuclear Information System (INIS)
Highly sensitive and selective detectors which are in the basis of some analytical devices, such as chromatograph Tzvet 500G attachment POU-80, gigrometer Enisej gas analyzer Platon that permit to control the production of As, P, Si, B hydrides, are tested. The techniques of tetermination of constant gases, general carbon, moisture in the mixtures based on As, P, Si, B hydrides with diluting gases (H2, He, Ar) as well as hydrides in them and in the air of working premises, are suggested
15. Interfacial study of semi-solid aluminum alloy and stainless steel sheathed extrusion
Institute of Scientific and Technical Information of China (English)
LIU Hong-wei; GUO Cheng; LIU Xu-feng; SHAO Guang-jie
2006-01-01
Using sheathed extrusion technique, the bonding and forming of semi solid aluminum alloy with stainless steel sheath are successfully realized. The relationship between the interfacial shear strength and the solid fraction of semi solid aluminum alloy at different extrusion ratios is analyzed; the interfacial and fracture structure of the sheath material are studied by optical microscopy(OM) and scanning electric microscopy(SEM). The result shows that interfacial shear strength increases with the increase of extrusion ratio, the maximum value of the interfacial shear strength is obtained when solid fraction of aluminum alloy is 30%,solid phase and liquid phase of the semi solid aluminum alloy are bonded with stainless steel by turns along the interface, and the aluminum alloy can not be peeled from the stainless steel completely, which means nicer bonding occurs at the interface.
16. Article having an improved platinum-aluminum-hafnium protective coating
Science.gov (United States)
Nagaraj, Bangalore Aswatha (Inventor); Williams, Jeffrey Lawrence (Inventor)
2005-01-01
An article protected by a protective coating has a substrate and a protective coating having an outer layer deposited upon the substrate surface and a diffusion zone formed by interdiffusion of the outer layer and the substrate. The protective coating includes platinum, aluminum, no more than about 2 weight percent hafnium, and substantially no silicon. The outer layer is substantially a single phase.
17. Spray Rolling Aluminum Strip
Energy Technology Data Exchange (ETDEWEB)
Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.
2006-05-10
Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.
18. Low Cost P/M Aluminum Syntactic Foam for Blade Containment in Turbine Engines Project
Data.gov (United States)
National Aeronautics and Space Administration — The proposed Phase I SBIR proposes a low density (0.75-1.2g/cc)syntactic aluminum foam energy absorber co-manufactured inside a composite fan case for turbine...
19. Ultrahigh vacuum system with aluminum
International Nuclear Information System (INIS)
A bakeable vacuum chamber (1500C continuous) consists of aluminum alloy beam pipe (6063-T6) and bellows (5052-F) with an aluminum alloy flange (2219-T87) and a metal seal [Helicoflex-HN: pure aluminum (1050) O-ring with an elastic core (Ni base super alloy Inconel 750) which supplies the sealing force] has been constructed. The beam pipe and the flange (6063-T6/2219-T87), and the bellows and the flange (5052-F/2219-T87) were welded by an alternate current (50 Hz) TIG process using an aluminum alloy filler wire (4043). The mechanical properties of the aluminum alloy (2219-T87) is suitable for using the Helicoflex O-ring but the groove surface for the gasket is weak for scratching. Cromium-nitride coating by ion plating method was carried out on the aluminum surface of the gasket groove [thickness: 16 μm, micro Vickers hardness: 1800]. Ordinary stainless steel vacuum system can be replaced by the aluminum vacuum system in an accelerator. (author)
20. Metal hydride hydrogen compression: recent advances and future prospects
Science.gov (United States)
Yartys, Volodymyr A.; Lototskyy, Mykhaylo; Linkov, Vladimir; Grant, David; Stuart, Alastair; Eriksen, Jon; Denys, Roman; Bowman, Robert C.
2016-04-01
Metal hydride (MH) thermal sorption compression is one of the more important applications of the MHs. The present paper reviews recent advances in the field based on the analysis of the fundamental principles of this technology. The performances when boosting hydrogen pressure, along with two- and three-step compression units, are analyzed. The paper includes also a theoretical modelling of a two-stage compressor aimed at describing the performance of the experimentally studied systems, their optimization and design of more advanced MH compressors. Business developments in the field are reviewed for the Norwegian company HYSTORSYS AS and the South African Institute for Advanced Materials Chemistry. Finally, future prospects are outlined presenting the role of the MH compression in the overall development of the hydrogen-driven energy systems. The work is based on the analysis of the development of the technology in Europe, USA and South Africa.
1. Final report for the DOE Metal Hydride Center of Excellence.
Energy Technology Data Exchange (ETDEWEB)
Keller, Jay O.; Klebanoff, Leonard E.
2012-01-01
This report summarizes the R&D activities within the U.S. Department of Energy Metal Hydride Center of Excellence (MHCoE) from March 2005 to June 2010. The purpose of the MHCoE has been to conduct highly collaborative and multi-disciplinary applied R&D to develop new reversible hydrogen storage materials that meet or exceed DOE 2010 and 2015 system goals for hydrogen storage materials. The MHCoE combines three broad areas: mechanisms and modeling (which provide a theoretically driven basis for pursuing new materials), materials development (in which new materials are synthesized and characterized) and system design and engineering (which allow these new materials to be realized as practical automotive hydrogen storage systems). This Final Report summarizes the organization and execution of the 5-year research program to develop practical hydrogen storage materials for light duty vehicles. Major results from the MHCoE are summarized, along with suggestions for future research areas.
2. Modelling zirconium hydrides using the special quasirandom structure approach
KAUST Repository
Wang, Hao
2013-01-01
The study of the structure and properties of zirconium hydrides is important for understanding the embrittlement of zirconium alloys used as cladding in light water nuclear reactors. Simulation of the defect processes is complicated due to the random distribution of the hydrogen atoms. We propose the use of the special quasirandom structure approach as a computationally efficient way to describe this random distribution. We have generated six special quasirandom structure cells based on face centered cubic and face centered tetragonal unit cells to describe ZrH2-x (x = 0.25-0.5). Using density functional theory calculations we investigate the mechanical properties, stability, and electronic structure of the alloys. © the Owner Societies 2013.
3. Delayed hydride cracking: theoretical model testing to predict cracking velocity
International Nuclear Information System (INIS)
Pressure tubes from Candu nuclear reactors as any other component manufactured with Zr alloys are prone to delayed hydride cracking. That is why it is important to be able to predict the cracking velocity during the component lifetime from parameters easy to be measured, such as: hydrogen concentration, mechanical and microstructural properties. Two of the theoretical models reported in literature to calculate the DHC velocity were chosen and combined, and using the appropriate variables allowed a comparison with experimental results of samples from Zr-2.5 Nb tubes with different mechanical and structural properties. In addition, velocities measured by other authors in irradiated materials could be reproduced using the model described above. (author)
4. [Microbiological corrosion of aluminum alloys].
Science.gov (United States)
Smirnov, V F; Belov, D V; Sokolova, T N; Kuzina, O V; Kartashov, V R
2008-01-01
Biological corrosion of ADO quality aluminum and aluminum-based construction materials (alloys V65, D16, and D16T) was studied. Thirteen microscopic fungus species and six bacterial species proved to be able to attack aluminum and its alloys. It was found that biocorrosion of metals by microscopic fungi and bacteria was mediated by certain exometabolites. Experiments on biocorrosion of the materials by the microscopic fungus Alternaria alternata, the most active biodegrader, demonstrated that the micromycete attack started with the appearance of exudate with pH 8-9 on end faces of the samples. PMID:18669265
5. Research on the methods to determine metallic aluminum content in aluminum nanoparticles
Energy Technology Data Exchange (ETDEWEB)
Chen Liang [State Key Lab of Materials Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Material Structure Department, Changjiang River Scientific Research Institute, Wuhan 430010 (China); Song Wulin, E-mail: wulins@126.com [State Key Lab of Materials Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China) and Analytical and Testing Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Lv Jie [State Key Lab of Materials Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen Xia [Analytical and Testing Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Xie Changsheng [State Key Lab of Materials Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)
2010-04-15
The high reactivity of aluminum nanoparticles (ANPs) made the determination of their metallic aluminum (Al) content difficult. Volumetric, thermogravimetry and permanganatometric methods were utilized to determine Al content. The reacted solution after volumetric measurement was further studied by transmission electron microscopy (TEM) and select area electron diffraction (SAED), which revealed that there were unreacted Al particles. Peaks indexed to metallic Al were found in the X-ray diffraction (XRD) pattern of the powders after thermogravimetry analysis (TGA). The side reactions between ANPs and water made the result of permanganatometric measurement underestimated as by the former methods. A modified titration method, using anhydrous alcohol as solvent, was performed to reduce the influence of water. The Al content of the ANPs produced by electro-exploded wire using this method was consistent with the quantitative phase analysis by Rietveld refinement.
6. Heat transfer characteristics of the metal hydride vessel based on the plate-fin type heat exchanger
Science.gov (United States)
Oi, Tsutomu; Maki, Kohei; Sakaki, Yoshinori
Heat transfer characteristics of the metal hydride vessel based on the plate-fin type heat exchanger were investigated. Metal hydride beds were filled with AB 2 type hydrogen-storage alloy's particles, Ti 0.42Zr 0.58Cr 0.78Fe 0.57Ni 0.2Mn 0.39Cu 0.03, with a storage capacity of 0.92 wt.%. Heat transfer model in the metal hydride bed based on the heat transfer mechanism for packed bed proposed by Kunii and co-workers is presented. The time-dependent hydrogen absorption/desorption rate and pressure in the metal hydride vessel calculated by the model were compared with the experimental results. During the hydriding, calculated hydrogen absorption rates agreed with measured ones. Calculated thermal equilibrium hydrogen pressures were slightly lower than the measured hydrogen pressures at the inlet of metal hydride vessel. Taking account of the pressure gradient between the inlet of metal hydride vessel and the metal hydride bed, it is considered that this discrepancy is reasonable. During the dehydriding, there were big differences between the calculated hydrogen desorption rates and measured ones. As calculated hydrogen desorption rates were lower than measured ones, there were big differences between the calculated thermal equilibrium hydrogen pressures and the measured hydrogen pressures at the inlet of metal hydride vessel. It is considered that those differences are due to the differences of the heat transfer characteristics such as thermal conductivity of metal hydride particles and porosity between the assumed and actual ones. It is important to obtain the heat transfer characteristics such as thermal conductivity of metal hydride particles and porosity both during the hydriding and dehydriding to design a metal hydride vessel.
7. Catalytic Radical Reduction in Aqueous Solution by a Ruthenium Hydride Intermediate.
Science.gov (United States)
Htet, Yamin; Tennyson, Andrew G
2016-07-18
Some manganese complexes can catalyze both antioxidant and pro-oxidant reactions, whereby the disparate reactivity modes are determined by the catalyst environment and afford distinct therapeutic effects. We recently reported the reduction of radicals in buffered aqueous solution catalyzed by a ruthenium complex with biologically relevant non-tertiary alcohols as terminal reductants. Mechanistic evidence is presented, indicating that this catalytic radical reduction is achieved by a Ru-hydride intermediate formed by β-hydride elimination from a Ru-alkoxide species. A similar mechanism and Ru-hydride intermediate was previously reported to kill cancer cells with catalytic pro-oxidant effects. Therefore, our demonstration of catalytic antioxidant effects by the same type of intermediate reveals new potential therapeutic strategies and applications for catalytic systems that form Ru-hydride intermediates. PMID:27254303
8. In situ probing of surface hydrides on hydrogenated amorphous silicon using attenuated total reflection infrared spectroscopy
CERN Document Server
Kessels, W M M; Sanden, M C M; Aydil, E S
2002-01-01
An in situ method based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is presented for detecting surface silicon hydrides on plasma deposited hydrogenated amorphous silicon (a-Si:H) films and for determining their surface concentrations. Surface silicon hydrides are desorbed by exposing the a-Si:H films to low energy ions from a low density Ar plasma and by comparing the infrared spectrum before and after this low energy ion bombardment, the absorptions by surface hydrides can sensitively be separated from absorptions by bulk hydrides incorporated into the film. An experimental comparison with other methods that utilize isotope exchange of the surface hydrogen with deuterium showed good agreement and the advantages and disadvantages of the different methods are discussed. Furthermore, the determination of the composition of the surface hydrogen bondings on the basis of the literature data on hydrogenated crystalline silicon surfaces is presented, and quantification of the h...
9. Hydride precipitation kinetics in Zircaloy-4 studied using synchrotron X-ray diffraction
Science.gov (United States)
Courty, Olivier F.; Motta, Arthur T.; Piotrowski, Christopher J.; Almer, Jonathan D.
2015-06-01
As a result of in-reactor corrosion during operation in nuclear reactors, hydrogen can enter the zirconium fuel cladding and precipitate as brittle hydride particles, which may reduce cladding ductility. Dissolved hydrogen responds to temperature gradients, resulting in transport and precipitation into cold spots so that the distribution of hydrides in the cladding is inhomogeneous. The hydrogen precipitation kinetics plays a strong role in the spatial distribution of the hydrides in the cladding. The precipitation rate is normally described as proportional to the supersaturation of hydrogen in solid solution. The proportionality constant, α2, for hydride precipitation in Zircaloy-4 is measured directly using in situ synchrotron X-Ray diffraction, at different temperatures and with three different initial hydrogen concentrations. The results validate the linear approximation of the phenomenological model and a near constant value of α2 = 4.5 × 10-4 s-1 was determined for the temperature range studied.
10. The two steps thermal decomposition of titanium hydride and two steps foaming of Al alloy
Institute of Scientific and Technical Information of China (English)
SHANG Jintang; HE Deping
2005-01-01
Two steps foaming (TSF) technique was proposed to prepare shaped Al alloy foam. Based on the thermal decomposition kinetics equation of titanium hydride, the relationship between two steps thermal decomposition kinetics of titanium hydride and two steps foaming Al alloy melt was studied. Two steps thermal decomposition curve of titanium hydride under increasing and constant temperature was calculated respectively. The hydrogen mass needed in the second foaming step was also calculated. Results showed that the hydrogen mass of the second thermal decomposition of titanium hydride is enough for the second foaming step in the condition of as-received Al melt foaming. Experimental and theoretical results indicate that two steps foaming technique can be used to prepare Al alloy foam with high porosity, shaped components and sandwich with Al alloy foam core.
11. Lateral epitaxial overgrowth of aluminum nitride and near ultraviolet LEDs for white lighting applications
Science.gov (United States)
Newman, Scott A.
In recent years, substantial efforts have been made to develop deep ultraviolet AlGaN-based LEDs (200-280 nm) for specialized applications such as bio-detection and non-line-of-sight (NLOS) communications. One of several factors limiting the performance of these devices is the high threading dislocation (TD) density of ˜5x109 cm-2 that results from growing the required AlN base layer on either a SiC or sapphire substrate. Lateral epitaxial overgrowth (LEO) of AlN, the first topic of this dissertation, is a promising technology for growing low TD density AlN templates. Conventional LEO methods relying on selective area growth (SAG) have not been effective for AlxGa1-xN with x > 0.2, because of the high aluminum sticking coefficient for the mask materials and/or contamination of the film by the mask. Therefore, maskless AlN LEO was investigated using metal organic chemical vapor deposition (MOCVD) and hydride vapor phase epitaxy (HVPE). Cracked AlN films with TD densities of color temperatures (CCTs) of ˜5,500 K and poor color rendering indices (CRIs) of ˜75. The alternative approach of combining a NUV LED with suitable NUV-excitation phosphors (e.g., red, green, and blue phosphors) can theoretically allow for high CRI white lighting with relatively good efficacy and a variety of CCTs. When this project began in late 2007, the lack of suitable blue-excitation phosphors suggested that this was the only viable approach to attaining very high CRI white lighting. NUV LEDs with AlN buffers on 6H-SiC substrates and AlGaN/InGaN active regions were first developed to target white phosphors with excitation peaks near 365 nm. Later, NUV LEDs with GaN buffers on sapphire substrates and GaN/InGaN active regions were developed to diagnose problems with the AlGaN/InGaN LEDs and to target white phosphors with excitation peaks near 400 nm. The best device produced in this study was a 410 nm GaN/InGaN LED which emitted 7.4 mW at 20 mA, with a maximum external quantum efficiency
12. The formation and characteristics of hydride blisters in c.w. Zircaloy-2 pressure tubes
International Nuclear Information System (INIS)
Under the auspices of the IAEA, a consultants' meeting was arranged in Vienna, 1994 July 25-29, at which a Canadian delegation, consisting of AECL and Ontario Hydro Technologies personnel, presented information on their knowledge of the behaviour of hydride blisters in Zircaloy-2 pressure tubes. This document contains the 10 papers presented by the Canadian delegation to the meeting. It is believed that they represent a good reference document on hydride blister phenomena
13. Dehydrogenation in lithium borohydride/conventional metal hydride composite based on a mutual catalysis
DEFF Research Database (Denmark)
Yu, X.B.; Shi, Qing; Vegge, Tejs;
2009-01-01
The dehydrogenation of LiBH4 ball-milled with hydrogenated 40Ti–15Mn–15Cr–30V alloy was investigated. It was found that there is a mutual catalysis between the two hydrides, lowering the temperature of hydrogen release from both hydrides. In the case of 1h milled LiBH4/40Ti–15Mn–15Cr–30V with a...
14. Atomic-Scale Chemical, Physical and Electronic Properties of the Subsurface Hydride of Palladium
Energy Technology Data Exchange (ETDEWEB)
Weiss, Paul
2014-01-20
We employed low-temperature, extreme-high vacuum scanning tunneling microscopy (STM) to investigate the roles of subsurface hydride (H) and deuteride (D) in the surface reconstruction and surface reactivity of Pd{110}. Specifically, we gained the ability to tailor the surface structure of Pd{110} both by preparation method and by deposition of deuterium from the gas phase. We observed thiophene at low coverage on Pd{110} to determine its adsorption orientation and electronic structure through scanning tunneling spectroscopy (STS) – namely, conductance spectroscopy and differential conductance imaging. We developed the methods necessary to coadsorb D adatoms with thiophene molecules, and to induce the reaction of individual molecules with predefined subsurface H or D features. In the case of Pd{110}, we found a much more pronounced effect from subsurface D, as it is influenced by the surface directionality. These experiments facilitate an understanding of the role of surface and subsurface H and D in heterogeneous catalytic processes, specifically in the hydrodesulfuization (HDS) of thiophene, an important and ubiquitous component found to be detrimental to petroleum refining.
15. Chrome - Free Aluminum Coating System
Science.gov (United States)
Bailey, John H.; Gugel, Jeffrey D.
2010-01-01
This slide presentation concerns the program to qualify a chrome free coating for aluminum. The program was required due to findings by OSHA and EPA, that hexavalent chromium, used to mitigate corrosion in aerospace aluminum alloys, poses hazards for personnel. This qualification consisted of over 4,000 tests. The tests revealed that a move away from Cr+6, required a system rather than individual components and that the maximum corrosion protection required pretreatment, primer and topcoat.
16. Investigation of Lithium Metal Hydride Materials for Mitigation of Deep Space Radiation
Science.gov (United States)
Rojdev, Kristina; Atwell, William
2016-01-01
Radiation exposure to crew, electronics, and non-metallic materials is one of many concerns with long-term, deep space travel. Mitigating this exposure is approached via a multi-faceted methodology focusing on multi-functional materials, vehicle configuration, and operational or mission constraints. In this set of research, we are focusing on new multi-functional materials that may have advantages over traditional shielding materials, such as polyethylene. Metal hydride materials are of particular interest for deep space radiation shielding due to their ability to store hydrogen, a low-Z material known to be an excellent radiation mitigator and a potential fuel source. We have previously investigated 41 different metal hydrides for their radiation mitigation potential. Of these metal hydrides, we found a set of lithium hydrides to be of particular interest due to their excellent shielding of galactic cosmic radiation. Given these results, we will continue our investigation of lithium hydrides by expanding our data set to include dose equivalent and to further understand why these materials outperformed polyethylene in a heavy ion environment. For this study, we used HZETRN 2010, a one-dimensional transport code developed by NASA Langley Research Center, to simulate radiation transport through the lithium hydrides. We focused on the 1977 solar minimum Galactic Cosmic Radiation environment and thicknesses of 1, 5, 10, 20, 30, 50, and 100 g/cm2 to stay consistent with our previous studies. The details of this work and the subsequent results will be discussed in this paper.
17. Influence of lanthanon hydride catalysts on hydrogen storage properties of sodium alanates
Institute of Scientific and Technical Information of China (English)
WU Zhe; CHEN Lixin; XIAO Xuezhang; FAN Xiulin; LI Shouquan; WANG Qidong
2013-01-01
NaAlH4 complex hydrides doped with lanthanon hydrides were prepared by hydrogenation of the ball-milled NaH/Al+xmol.％ RE-H composites (RE=La,Ce; x=2,4,6) using NaHl and A1 powder as raw materials.The influence of lanthanon hydride catalysts on the hydriding and dehydriding behaviors of the as-synthesized composites were investigated.It was found that the composite doped with 2 mol.％ La.H3.01 displayed the highest hydrogen absorption capacity of 4.78 wt.％ and desorption capacity of 4.66wt.％,respectively.Moreover,the composite doped with 6 mol％ CeH2.51 showed the best hydriding/dehydriding reaction kinetics.The proposed catalytic mechanism for reversible hydrogen storage properties of the composite was attributed to the presence of active LaH3.01 and CeH2.51 particles,which were scattering on the surface of NaH and A1 particles,acting as the catalytic active sites for hydrogen diffusion and playing an important catalytic role in the improved hydriding/dehydriding reaction.
18. A Virtual Aluminum Reduction Cell
Science.gov (United States)
Zhang, Hongliang; Zhou, Chenn Q.; Wu, Bing; Li, Jie
2013-11-01
The most important component in the aluminum industry is the aluminum reduction cell; it has received considerable interests and resources to conduct research to improve its productivity and energy efficiency. The current study focused on the integration of numerical simulation data and virtual reality technology to create a scientifically and practically realistic virtual aluminum reduction cell by presenting complex cell structures and physical-chemical phenomena. The multiphysical field simulation models were first built and solved in ANSYS software (ANSYS Inc., Canonsburg, PA, USA). Then, the methodology of combining the simulation results with virtual reality was introduced, and a virtual aluminum reduction cell was created. The demonstration showed that a computer-based world could be created in which people who are not analysis experts can see the detailed cell structure in a context that they can understand easily. With the application of the virtual aluminum reduction cell, even people who are familiar with aluminum reduction cell operations can gain insights that make it possible to understand the root causes of observed problems and plan design changes in much less time.
19. Selenium adsorption to aluminum-based water treatment residuals
Energy Technology Data Exchange (ETDEWEB)
Ippolito, James A.; Scheckel, Kirk G.; Barbarick, Ken A.; (US-Agriculture); (EPA); (CSU)
2009-09-02
Aluminum-based water treatment residuals (WTR) can adsorb water- and soil-borne P, As(V), As(III), and perchlorate, and may be able to adsorb excess environmental selenium. WTR, clay minerals, and amorphous aluminum hydroxide were shaken for 24 h in selenate or selenite solutions at pH values of 5-9, and then analyzed for selenium content. Selenate and selenite adsorption edges were unaffected across the pH range studied. Selenate adsorbed on to WTR, reference mineral phases, and amorphous aluminum hydroxide occurred as outer sphere complexes (relatively loosely bound), while selenite adsorption was identified as inner-sphere complexation (relatively tightly bound). Selenite sorption to WTR in an anoxic environment reduced Se(IV) to Se(0), and oxidation of Se(0) or Se(IV) appeared irreversible once sorbed to WTR. Al-based WTR could play a favorable role in sequestering excess Se in affected water sources.
20. Recovery of rare earths from acid leach solutions of spent nickel-metal hydride batteries using solvent extraction
Institute of Scientific and Technical Information of China (English)
夏允; 肖连生; 田吉英; 李兆洋; 曾理
2015-01-01
The extraction of rare earths from acid leach solutions of spent nickel-metal hydride batteries using a primary amine ex-tractant of N1923 was studied. The effects of feed pH, temperature, agitation rate and time on the extraction of rare earths, as well as stripping agent composition and concentration, phase ratio on the stripping were investigated. In addition, the extraction isotherm was determined. The pilot plant test results showed that the extraction of rare earths reached 99.98% after a five-stage counter current ex-traction. The mixed rare earths oxalates with the 99.77% purity of rare earth elements and impurity content less than 0.05% were ob-tained by the addition of oxalic acids in loaded strip liquors. The extractant exhibited good selectivity of rare earths over base metals of iron, nickel, copper and manganese.
1. Small-angle neutron scattering measurements of deuteride (hydride) formation and decomposition in single-crystal Pd
International Nuclear Information System (INIS)
The deuteride (hydride) precipitation and decomposition microstructure in single-crystal Pd has been investigated in a series of in situ small-angle neutron scattering (SANS) measurements. The particle morphology along the absorption and desorption branches of the 353-K pressure-composition isotherm are consistent with a loss of particle coherency, leading to the formation of large, micron-thick plates. The loss of coherency coincides with the system entering the miscibility gap, an observation that suggests irreversible dislocation formation in part drives the hysteretic behavior of the Pd-D (-H) system. SANS analysis further indicates that the decomposition process is characterized by a much higher particle dispersion, with a factor of 40 greater surface-to-volume ratio of the precipitating phase. This we attribute to a more heterogeneous transformation process, presumably at dislocations formed during initial deuteride formation
2. The oxidation and hydriding of zircaloy fuel cladding in high temperature aqueous solutions
Science.gov (United States)
Chen, Yingzi
Nearly 90% of today's fission reactors use Zr based fuel cladding materials. The Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs) are the two most common water-cooled nuclear reactors. Corrosion is the principal threat to the failure of the fuel in these reactors, resulting in the release of fission products to the coolant and hence to the establishment of radiation fields in out-of-core regions of the coolant circuit (e.g., steam generators in PWRs and turbines in BWRs). As is well known, corrosion is an electrochemical phenomenon; however, electrochemical effects are often neglected in corrosion studies on zirconium and its alloys, because of the difficulty in performing well-defined experiments under the appropriate conditions (high temperatures and pressures). In-situ studies have been carried out to examine the electrochemistry of passive zirconium under simulated BWR and PWR coolant conditions by using a controlled hydrodynamic, high temperature/high pressure test cell. The oxidation/hydriding mechanisms are elucidated by measuring the current, impedance, and capacitance of passive zirconium as a function of formation potential. The data are interpreted in terms of a modified point defect model (PDM) that recognize the existence of a passive film comprising a thick oxide outer layer over a thin barrier layer. From the composition of the zirconium passive film and thermodynamic analysis, it is postulated that a hydride barrier layer forms under PWR coolant conditions whereas an oxide barrier layer forms under BWR primary coolant conditions. Transients in current density and the thickness of the passive film formed on zirconium, when stepping the potential in either the positive or negative directions, have confirmed that the rate law afforded by the PDM adequately describes the growth and thinning of the passive film at high temperatures. The experimental results demonstrate that the kinetics of either oxygen or hydrogen vacancy generation
3. Hydriding/dehydriding behavior of Mg{sub 2}CoH{sub 5} produced by reactive mechanical milling
Energy Technology Data Exchange (ETDEWEB)
Fernandez, I. Gonzalez [Instituto Balseiro, U.N. Cuyo (Argentina); Meyer, G.O. [Instituto Balseiro, U.N. Cuyo (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, CONICET (Argentina); Centro Atomico Bariloche (CNEA), R8402AGP, S.C. de Bariloche (Argentina); Gennari, F.C. [Instituto Balseiro, U.N. Cuyo (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, CONICET (Argentina); Centro Atomico Bariloche (CNEA), R8402AGP, S.C. de Bariloche (Argentina)], E-mail: gennari@cab.cnea.gov.ar
2008-09-22
Complex Mg{sub 2}CoH{sub 5} hydride was obtained by a combined procedure that included a milling stage of a 2Mg-Co mixture under argon followed by reactive mechanical alloying (RMA) under hydrogen, both at room temperature. During RMA, MgH{sub 2} is produced at short milling times (10 h) and Mg{sub 2}CoH{sub 5} (50 wt%) after 90 h. Improvement in the yield and the formation times could be associated with both refinement of microstructure and enhancement of intermixing of Mg-Co during pre-milling stage. DSC studies of Mg{sub 2}CoH{sub 5} phase produced by RMA show that the starting decomposition temperature is about 205 deg. C. Absorption and desorption PCIs were determined under static (300 deg. C) and dynamic (230-330 deg. C) conditions. An important hysteresis and two plateaus were observed and correlated with formation/decomposition of Mg{sub 2}CoH{sub 5} (high-pressure plateau) and Mg{sub 6}Co{sub 2}H{sub 11} (low-pressure plateau) hydrides. For comparing hydrogen sorption kinetics, Mg{sub 2}CoH{sub 5} (65 wt%) was also obtained by a sintering method at 410 deg. C and 6.0 MPa of hydrogen pressure. Absorption was very fast in the temperature range of 150-350 deg. C, independently of synthesis procedure. However, desorption curves showed a better behavior for RMA powders. MgCo was observed after decomposition of Mg{sub 2}CoH{sub 5} under particular thermal treatments, while MgCo{sub 2} phase was not detected. The results of this study reinforce the idea that kinetics factors related with atomic mobility play a key role in the formation of Mg-Co intermetallics.
4. Stacking structures and electrode performances of rare earth-Mg-Ni-based alloys for advanced nickel-metal hydride battery
International Nuclear Information System (INIS)
Rare earth-Mg-Ni-based alloys with stacking structures consisting of AB5 unit (CaCu5-type structure) and A2B4 unit (Laves structure) have received attention as negative electrode materials for advanced nickel-metal hydride (Ni-MH) battery. These alloy materials are very attractive because of high hydrogen storage capacity, low cobalt content and moderate plateau pressure, but have some difficulty to control the phase abundance and electrode performances. In this paper, relationship among composition, phase abundance, and electrochemical properties was investigated. Structural analysis was done using synchrotron X-ray diffraction patterns. In alloys such as La0.8Mg0.2Ni3.4-x-yCo0.3(MnAl)x (0 ≤ x ≤ 0.4), phase abundance was drastically changed with increasing amount of Mn and Al. In the range of 0.1 5Co19-type (5:19H) or rhombohedral 1:4R phases were dominant. The Rietveld analysis suggested that Mg occupies La sites in A2B4 unit, and Al has tendency to occupy Ni sites between A2B4 unit and AB5 unit or between AB5 units in these types of phases. The developed alloys showed higher discharge capacity by 20% than the conventional one at a 0.2 C discharge rate
5. Low-aluminum content iron-aluminum alloys
Energy Technology Data Exchange (ETDEWEB)
Sikka, V.K.; Goodwin, G.M.; Alexander, D.J. [and others
1995-06-01
The low-aluminum-content iron-aluminum program deals with the development of a Fe-Al alloy with aluminum content such as a produce the minimum environmental effect at room temperature. The FAPY is an Fe-16 at. % Al-based alloy developed at the Oak Ridge National Laboratory as the highest aluminum-containing alloy with essentially no environmental effect. The chemical composition for FAPY in weight percent is: aluminum = 8.46, chromium = 5.50, zirconium = 0.20, carbon = 0.03, molybdenum = 2.00, yttrium = 0.10 and iron = 83.71. The ignots of the alloy can be hot worked by extrusion, forging, and rolling processes. The hot-worked cast structure can be cold worked with intermediate anneals at 800{degrees}C. Typical room-temperature ductility of the fine-grained wrought structure is 20 to 25% for this alloy. In contrast to the wrought structure, the cast ductility at room temperature is approximately 1% with a transition temperature of approximately 100 to 150{degrees}C, above which ductility values exceed 20%. The alloy has been melted and processed into bar, sheet, and foil. The alloy has also been cast into slabs, step-blocks of varying thicknesses, and shapes. The purpose of this section is to describe the welding response of cast slabs of three different thicknesses of FAPY alloy. Tensile, creep, and Charpy-impact data of the welded plates are also presented.
6. A High-Fe Aluminum Matrix Welding Filler Metal for Hardfacing Aluminum-Silicon Alloys
Institute of Scientific and Technical Information of China (English)
2003-01-01
A high-Fe containing aluminum matrix filler metal for hardfacing aluminum-silicon alloys has been developed by using iron,nickel,and silicon as the major strengthening elements,and by measuring mechanical properties,room temperature and high temperature wear tests,and microstructural analysis.The filler metal,which contains 3.0%-5.0% Fe and 11.0%-13.0% Si,exhibits an excellent weldability.The as-cast and as-welded microstructures for the filler metal are of uniformly distribution and its dispersed network of hard phase is enriched with Al-Si-Fe-Ni.The filler metal shows high mechanical properties and wear resistance at both room temperature and high temperatures.The deposited metal has a better resistance to impact wear at 220℃ than that of substrate Al-Si-Mg-Cu piston alloy;at room temperature,the deposited metal has an equivalent resistance to slide wear with lubrication as that of a hyper-eutectic aluminum-silicon alloy with 27% Si and 1% Ni.
7. Alkaline corrosion properties of laser-clad aluminum/titanium coatings
DEFF Research Database (Denmark)
Aggerbeck, Martin; Herbreteau, Alexis; Rombouts, Marleen;
2015-01-01
with supersaturated titanium ( (1 weight per cent), Al3Ti intermetallics and large partially undissolved Ti6Al4V particles. Heat treatment lowered the titanium concentration in the aluminum matrix, changed the shape of the Al3Ti precipitates and increased the degree of dissolution of the Ti6Al4V particles. Corrosion...... testing showed significant localized dissolution of the aluminum matrix. Research limitations/implications – Increased titanium concentration and heat treatment gave improved alkaline corrosion properties. At pH 13.5, the Al3Ti phases were protected, while the aluminum matrix corroded. Practical...... implications – For alkaline corrosion-protection of aluminum in the automobile industry, titanium might be useful at pH values below 13.5 or by using other coating techniques. Originality/value – This is the first study testing the use of titanium as a protective element of aluminum in stringent alkaline...
8. 用于高效液相色谱和开管毛细管电色谱的氢化硅胶分离材料%Hydride-Based Separation Materials for High Performance Liquid Chromatography and Open Tubular Capillary Electrochromatography
Institute of Scientific and Technical Information of China (English)
PESEK Joseph J; MATYSKA Maria T
2005-01-01
Silica hydride is a recent development in chromatographic support materials for high performance liquid chromatography (HPLC) where hydride groups replace 95% of the silanols on the surface. This conversion changes many of the fundamental properties of the material as well as the bonded stationary phases that are the result of further chemical modification of the hydride surface. Some unique chromatographic properties of hydride-based phases are described as well as some general application areas where these bonded materials may be used in preference to or have advantages not available from typical stationary phases. The fabrication, properties and applications of etched chemically modified capillaries for electrophoretic analysis are also reviewed. It is shown that the etching process creates a surface that is fundamentally different than a bare fused silica capillary. The new surface matrix produces unique electroosmotic flow properties and is more compatible with basic and biological compounds. After chemical modification of the surface, the bonded organic moiety (stationary phase) contributes to the control of migration of solutes in the capillary. Both electrophoretic and chromatographic processes take place in the etched chemically modified capillaries leading to a variety of experimental variables that can be used to optimize separations. A number of examples of separations on these capillaries are described.
9. Geochemistry of Aluminum in High Temperature Brines
Energy Technology Data Exchange (ETDEWEB)
Benezeth, P.; Palmer, D.A.; Wesolowski, D.J.
1999-05-18
The objective ofthis research is to provide quantitative data on the equilibrium and thermodynamic properties of aluminum minerals required to model changes in permeability and brine chemistry associated with fluid/rock interactions in the recharge, reservoir, and discharge zones of active geothermal systems. This requires a precise knowledge of the thermodynamics and speciation of aluminum in aqueous brines, spanning the temperature and fluid composition rangesencountered in active systems. The empirical and semi-empirical treatments of the solubility/hydrolysis experimental results on single aluminum mineral phases form the basis for the ultimate investigation of the behavior of complex aluminosilicate minerals. The principal objective in FY 1998 was to complete the solubility measurements on boehmite (AIOOH) inNaC1 media( 1 .O and 5.0 molal ionic strength, IOO-250°C). However, additional measurements were also made on boehmite solubility in pure NaOH solutions in order to bolster the database for fitting in-house isopiestic data on this system. Preliminary kinetic Measurements of the dissolution/precipitation of boehmite was also carried out, although these were also not planned in the earlier objective. The 1999 objectives are to incorporate these treatments into existing codes used by the geothermal industry to predict the chemistry ofthe reservoirs; these calculations will be tested for reliability against our laboratory results and field observations. Moreover, based on the success of the experimental methods developed in this program, we intend to use our unique high temperature pH easurement capabilities to make kinetic and equilibrium studies of pH-dependent aluminosilicate transformation reactions and other pH-dependent heterogeneous reactions.
10. Hydrides of CeNi5, MmNi5, Ca02(Ce065Mm035)08Ni5, Ca02Ce08Ni5, Ca02Mm08Ni5, and mixed CeNi5/MmNi5
International Nuclear Information System (INIS)
Six intermetallic alloys [CeNi5, MmNi5, Ca02(Ce065Mm035)08Ni5, Ca02Ce08Ni5, Ca02Mm08Ni5, and a mixed alloy, CeNi5/MmNi5] were investigated with respect to their suitability to provide high hydrogen capacity and their potential for use in providing substantial hydrogen pressure at both low and high temperatures. A second phase of our investigation dealt with ball-milling and hydriding and dehydriding cycles to produce fine particles for use in hydride powder transfer studies. A summary of several Van't Hoff plots is also included for hydride-forming alloys
11. Temperature Controlled Laser Joining of Aluminum to Galvanized Steel
Science.gov (United States)
Weller, Daniel; Simon, Jörg; Stritt, Peter; Weber, Rudolf; Graf, Thomas; Bezençon, Cyrille; Bassi, Corrado
Reliable joining of 6000 series aluminum alloy to galvanized steel is a challenge for current manufacturing technologies. To control and limit the formation of brittle intermetallic phases, mixing of both metals in liquid state has to be avoided. It has been shown that laser weld-brazing is a possible process. Thereby the aluminum and zinc layer of the galvanized steel are molten and the steel remains solid during the process. In addition, to avoid zinc degassing, the aluminum melt bath temperature has to be below zinc boiling temperature of 907°C. To meet these requirements a temperature controlled laser process was developed, allowing to join the two materials without flux and filler material. The thickness of the intermetallic layer shows a dependency on the set temperature used to control the process. At optimum set temperature the thickness of intermetallic phases can be limited to about 5 μm. Tensile strengths of the joints of up to 75% of the aluminum base material were achieved.
12. Scaleable Clean Aluminum Melting Systems
Energy Technology Data Exchange (ETDEWEB)
Han, Q.; Das, S.K. (Secat, Inc.)
2008-02-15
The project entitled 'Scaleable Clean Aluminum Melting Systems' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Secat Inc. The three-year project was initially funded for the first year and was then canceled due to funding cuts at the DOE headquarters. The limited funds allowed the research team to visit industrial sites and investigate the status of using immersion heaters for aluminum melting applications. Primary concepts were proposed on the design of furnaces using immersion heaters for melting. The proposed project can continue if the funding agency resumes the funds to this research. The objective of this project was to develop and demonstrate integrated, retrofitable technologies for clean melting systems for aluminum in both the Metal Casting and integrated aluminum processing industries. The scope focused on immersion heating coupled with metal circulation systems that provide significant opportunity for energy savings as well as reduction of melt loss in the form of dross. The project aimed at the development and integration of technologies that would enable significant reduction in the energy consumption and environmental impacts of melting aluminum through substitution of immersion heating for the conventional radiant burner methods used in reverberatory furnaces. Specifically, the program would couple heater improvements with furnace modeling that would enable cost-effective retrofits to a range of existing furnace sizes, reducing the economic barrier to application.
13. Zintl and intermetallic phases grown from calcium/lithium flux
Science.gov (United States)
Blankenship, Trevor
, (Im-3, a = 9.6055(8)A) which contains C 34- units. A very similar phase, Ba12InC 18H4 (Im-3,a = 11.1415(8) A), was grown from the reaction of indium, carbon, and LiH in Ba/Li flux. This compound also includes C34- units. Preliminary Ca/Li flux reactions of aluminum with other main group elements have produced several new phases: a hydride clathrate Ca31Al2H25 in cubic Fd-3m (a=18.0835(15) A), Ca24Al2(C 1-xHx)N2H16 in tetragonal P42/nmc (a=15.9069(12) A, c=13.7323(10) A, and Ca 4Al2N5 in orthorhombic Pna21 (a = 11.2331(1) A, b=9.0768(8) A, c=6.0093(5) A.
14. TANK 12 SLUDGE CHARACTERIZATION AND ALUMINUM DISSOLUTION DEMONSTRATION
International Nuclear Information System (INIS)
A 3-L sludge slurry sample from Tank 12 was characterized and then processed through an aluminum dissolution demonstration. The dominant constituent of the sludge was found to be aluminum in the form of boehmite. The iron content was minor, about one-tenth that of the aluminum. The salt content of the supernatant was relatively high, with a sodium concentration of ∼7 M. Due to these characteristics, the yield stress and plastic viscosity of the unprocessed slurry were relatively high (19 Pa and 27 cP), and the settling rate of the sludge was relatively low (∼20% settling over a two and a half week period). Prior to performing aluminum dissolution, plutonium and gadolinium were added to the slurry to simulate receipt of plutonium waste from H-Canyon. Aluminum dissolution was performed over a 26 day period at a temperature of 65 C. Approximately 60% of the insoluble aluminum dissolved during the demonstration, with the rate of dissolution slowing significantly by the end of the demonstration period. In contrast, approximately 20% of the plutonium and less than 1% of the gadolinium partitioned to the liquid phase. However, about a third of the liquid phase plutonium became solubilized prior to the dissolution period, when the H-Canyon plutonium/gadolinium simulant was added to the Tank 12 slurry. Quantification of iron dissolution was less clear, but appeared to be on the order of 1% based on the majority of data (a minor portion of the data suggested iron dissolution could be as high as 10%). The yield stress of the post-dissolution slurry (2.5 Pa) was an order of magnitude lower than the initial slurry, due most likely to the reduced insoluble solids content caused by aluminum dissolution. In contrast, the plastic viscosity remained unchanged (27 cP). The settling rate of the post-dissolution slurry was higher than the initial slurry, but still relatively low compared to settling of typical high iron content/low salt content sludges. Approximately 40% of the
15. TANK 12 SLUDGE CHARACTERIZATION AND ALUMINUM DISSOLUTION DEMONSTRATION
Energy Technology Data Exchange (ETDEWEB)
Reboul, S; Michael Hay, M; Kristine Zeigler, K; Michael Stone, M
2009-03-25
A 3-L sludge slurry sample from Tank 12 was characterized and then processed through an aluminum dissolution demonstration. The dominant constituent of the sludge was found to be aluminum in the form of boehmite. The iron content was minor, about one-tenth that of the aluminum. The salt content of the supernatant was relatively high, with a sodium concentration of {approx}7 M. Due to these characteristics, the yield stress and plastic viscosity of the unprocessed slurry were relatively high (19 Pa and 27 cP), and the settling rate of the sludge was relatively low ({approx}20% settling over a two and a half week period). Prior to performing aluminum dissolution, plutonium and gadolinium were added to the slurry to simulate receipt of plutonium waste from H-Canyon. Aluminum dissolution was performed over a 26 day period at a temperature of 65 C. Approximately 60% of the insoluble aluminum dissolved during the demonstration, with the rate of dissolution slowing significantly by the end of the demonstration period. In contrast, approximately 20% of the plutonium and less than 1% of the gadolinium partitioned to the liquid phase. However, about a third of the liquid phase plutonium became solubilized prior to the dissolution period, when the H-Canyon plutonium/gadolinium simulant was added to the Tank 12 slurry. Quantification of iron dissolution was less clear, but appeared to be on the order of 1% based on the majority of data (a minor portion of the data suggested iron dissolution could be as high as 10%). The yield stress of the post-dissolution slurry (2.5 Pa) was an order of magnitude lower than the initial slurry, due most likely to the reduced insoluble solids content caused by aluminum dissolution. In contrast, the plastic viscosity remained unchanged (27 cP). The settling rate of the post-dissolution slurry was higher than the initial slurry, but still relatively low compared to settling of typical high iron content/low salt content sludges. Approximately 40
16. Tank 12 Sludge Characterization and Aluminum Dissolution Demonstration
Energy Technology Data Exchange (ETDEWEB)
Reboul, S.; Hay, M.; Zeigler, K; Stone, M.
2010-05-05
A 3-L sludge slurry sample from Tank 12 was characterized and then processed through an aluminum dissolution demonstration. The dominant constituent of the sludge was found to be aluminum in the form of boehmite. The iron content was minor, about one-tenth that of the aluminum. The salt content of the supernatant was relatively high, with a sodium concentration of {approx}7 M. Due to these characteristics, the yield stress and plastic viscosity of the unprocessed slurry were relatively high (19 Pa and 27 cP), and the settling rate of the sludge was relatively low ({approx}20% settling over a two and a half week period). Prior to performing aluminum dissolution, plutonium and gadolinium were added to the slurry to simulate receipt of plutonium waste from H-Canyon. Aluminum dissolution was performed over a 26 day period at a temperature of 65 C. Approximately 60% of the insoluble aluminum dissolved during the demonstration, with the rate of dissolution slowing significantly by the end of the demonstration period. In contrast, approximately 20% of the plutonium and less than 1% of the gadolinium partitioned to the liquid phase. However, about a third of the liquid phase plutonium became solubilized prior to the dissolution period, when the H-Canyon plutonium/gadolinium simulant was added to the Tank 12 slurry. Quantification of iron dissolution was less clear, but appeared to be on the order of 1% based on the majority of data (a minor portion of the data suggested iron dissolution could be as high as 10%). The yield stress of the post-dissolution slurry (2.5 Pa) was an order of magnitude lower than the initial slurry, due most likely to the reduced insoluble solids content caused by aluminum dissolution. In contrast, the plastic viscosity remained unchanged (27 cP). The settling rate of the post-dissolution slurry was higher than the initial slurry, but still relatively low compared to settling of typical high iron content/low salt content sludges. Approximately 40
17. Influence of hydrides orientation on strain, damage and failure of hydrided zircaloy-4; Influence de l'orientation des hydrures sur les modes de deformation, d'endommagement et de rupture du zircaloy-4 hydrure
Energy Technology Data Exchange (ETDEWEB)
Racine, A
2005-09-15
In pressurized water reactors of nuclear power plants, fuel pellets are contained in cladding tubes, made of Zirconium alloy, for instance Zircaloy-4. During their life in the primary water of the reactor (155 bars, 300 C), cladding tubes are oxidized and consequently hydrided. A part of the hydrogen given off precipitates as Zirconium hydrides in the bulk material and embrittles the material. This embrittlement depends on many parameters, among which hydrogen content and orientation of hydrides with respect to the applied stress. This investigation is devoted to the influence of the orientation of hydrides with respect to the applied stress on strain, damage and failure mechanisms. Macroscopic and SEM in-situ ring tensile tests are performed on cladding tube material (unirradiated cold worked stress-relieved Zircaloy-4) hydrided with about 200 and 500 wppm hydrogen, and with different main hydrides orientation: either parallel or perpendicular to the circumferential tensile direction. We get the mechanical response of the material as a function of hydride orientation and hydrogen content and we investigate the deformation, damage and failure mechanisms. In both cases, digital image correlation techniques are used to estimate local and global strain distributions. Neither the tensile stress-strain response nor the global and local strain modes are significantly affected by hydrogen content or hydride orientation, but the failure modes are strongly modified. Indeed, only 200 wppm radial hydrides embrittle Zy-4: sample fail in the elastic domain at about 350 MPa before strain bands could develop; whereas in other cases sample reach at least 750 MPa before necking and final failure, in ductile or brittle mode. To model this particular heterogeneous material behavior, a non-coupled damage approach which takes into account the anisotropic distribution of the hydrides is proposed. Its parameters are identified from the macroscopic strain field measurements and a
18. Improved Electrochemical Performance of Surface-Modified Metal Hydride Electrodes
Institute of Scientific and Technical Information of China (English)
YANG Kai; WU Feng; CHEN Shi; ZHANG Cun-zhong
2005-01-01
A novel plating process was applied to the surface modification of the metal hydride (MH) electrode of the MH/Ni batteries. The electrode was plated with a thin nickel film about 0.1 μm thick by using multi-arc ion plating technique. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to analyze the electrodes. Influence of the surface modification on the performance of the MH/Ni batteries was studied. It is shown that the surface modification could enhance the electrode conductivity and decrease the batteries ohimic resistance by 28.2 %. After surface modification, the discharge capacity of modification also improves the cyclic durability of the batteries. The inner pressure of the batteries with modified electrode during overcharging is much lower than that with unmodified electrode. The experimental results demonstrate that this process is an effective way for the surface modification of the electrode of MH/Ni batteries.
19. Superhalogens as Building Blocks of Complex Hydrides for Hydrogen Storage
CERN Document Server
Srivastava, Ambrish Kumar
2016-01-01
Superhalogens are species whose electron affinity (EA) or vertical detachment energy (VDE) exceed to those of halogen. These species typically consist of a central electropositive atom with electronegative ligands. The EA or VDE of species can be further increased by using superhalogen as ligands, which are termed as hyperhalogen. Having established BH4- as a superhalogen, we have studied BH4-x(BH4)x- (x = 1 to 4) hyperhalogen anions and their Li-complexes, LiBH4-x(BH4)x using density functional theory. The VDE of these anions is larger than that of BH4-, which increases with the increase in the number of peripheral BH4 moieties (x). The hydrogen storage capacity of LiBH4-x(BH4)x complexes is higher but binding energy is smaller than that of LiBH4, a typical complex hydride. The linear correlation between dehydrogenation energy of LiBH4-x(BH4)x complexes and VDE of BH4-x(BH4)x- anions is established. These complexes are found to be thermodynamically stable against dissociation into LiBH4 and borane. This stud...
20. Unloading Effect on Delayed Hydride Cracking in Zirconium Alloys
Energy Technology Data Exchange (ETDEWEB)
Kim, Young Suk; Kim, Sung Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2010-05-15
1. Improving of Corrosion Resistance of Aluminum Alloys by Removing Intermetallic Compound
Energy Technology Data Exchange (ETDEWEB)
Seri, Osami [Muroran it., Hokkaido (Japan)
2008-06-15
It is well known that iron is one of the most common impurity elements sound in aluminum and its alloys. Iron in the aluminum forms an intermetallic compounds such as FeAl{sub 3}. The FeAl{sub 3} particles on the aluminum surface are one of the most detrimental phases to the corrosion process and anodizing procedure for aluminum and its alloys. Trial and error surface treatment will be carried out to find the preferential and effective removal of FeAl{sub 3} particles on the surfaces without dissolution of aluminum matrix around the particles. One of the preferable surface treatments for the aim of getting FeAl{sub 3} free surface was an electrochemical treatment such as cathodic current density of -2 kAm{sup -2} in a 20-30 mass% HNO{sub 3} solution for the period of 300s. The corrosion characteristics of aluminum surface with FeAl{sub 3} free particles are examined in a 0.1 kmol/m{sup 3} NaCl solution. It is found that aluminum with free FeAl{sub 3} particles shows higher corrosion resistance than aluminum with FeAl{sub 3} particles.
2. Rechargeable Aluminum-Ion Batteries
Energy Technology Data Exchange (ETDEWEB)
Paranthaman, Mariappan Parans [ORNL; Liu, Hansan [ORNL; Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL; Brown, Gilbert M [ORNL
2015-01-01
This chapter reports on the development of rechargeable aluminum-ion batteries. A possible concept of rechargeable aluminum/aluminum-ion battery based on low-cost, earth-abundant Al anode, ionic liquid EMImCl:AlCl3 (1-ethyl-3-methyl imidazolium chloroaluminate) electrolytes and MnO2 cathode has been proposed. Al anode has been reported to show good reversibility in acid melts. However, due to the problems in demonstrating the reversibility in cathodes, alternate battery cathodes and battery concepts have also been presented. New ionic liquid electrolytes for reversible Al dissolution and deposition are needed in the future for replacing corrosive EMImCl:AlCl3 electrolytes.
3. 21 CFR 172.310 - Aluminum nicotinate.
Science.gov (United States)
2010-04-01
... Special Dietary and Nutritional Additives § 172.310 Aluminum nicotinate. Aluminum nicotinate may be safely... additive, expressed as niacin, shall appear on the label of the food additive container or on that of...
4. Baise to Build Ecological Aluminum Industry Base
Institute of Scientific and Technical Information of China (English)
2011-01-01
<正>The government of Baise announced the construction of an ecological aluminum industry base over the next few years,pledging to turn the city into a major aluminum industry base in China and the rest of Asia.
5. Environmental Control over the Primary Aluminum Industry
Institute of Scientific and Technical Information of China (English)
2004-01-01
<正> To strengthen environmental control over theprimary aluminum industry,the State Environ-mental Protection Administration of China hasrecently issued a notice addressing the follow-ing points:Strengthening environmental control over theexisting primary aluminum companies
6. Decreasing residual aluminum level in drinking water
Institute of Scientific and Technical Information of China (English)
王志红; 崔福义
2004-01-01
The relativity of coagulant dosage, residual turbidity, temperature, pH etc. with residual aluminum concentration were investigated, and several important conclusions were achieved. Firstly, dosage of alum-coagulant or PAC1 influences residual aluminum concentration greatly. There is an optimal-dosage-to-aluminum, a bit less than the optimal-dosage-to-turbidity. Secondly, it proposes that decreasing residual aluminum concentration can be theoretically divided into two methods, either decreasing (even removing) the concentration of particulate aluminum component, or decreasing dissolved aluminum. In these tests there is an optimal value of residual turbidity of postprecipitation at 7.0 NTU. Thirdly, residual aluminum level will increase while water temperature goes higher. At the last, optimal pH value corresponds a minimum dissolved aluminum at a given turbidity. Data shows the optimal pH value decreases with water temperature's increasing.
7. OPTIMIZING AN ALUMINUM EXTRUSION PROCESS
Directory of Open Access Journals (Sweden)
Mohammed Ali Hajeeh
2013-01-01
Full Text Available Minimizing the amount of scrap generated in an aluminum extrusion process. An optimizing model is constructed in order to select the best cutting patterns of aluminum logs and billets of various sizes and shapes. The model applied to real data obtained from an existing extrusion factory in Kuwait. Results from using the suggested model provided substantial reductions in the amount of scrap generated. Using sound mathematical approaches contribute significantly in reducing waste and savings when compared to the existing non scientific techniques.
8. Another Look at the Mechanisms of Hydride Transfer Enzymes from Quantum and Classical Transition Path Sampling
Science.gov (United States)
Dzierlenga, Michael; Antoniou, Dimitri; Schwartz, Steven
2015-03-01
The mechanisms involved in enzymatic hydride transfer have been studies for years but questions remain, due to the difficulty in determining the participation of protein dynamics and quantum effects, especially hydrogen tunneling. In this study, we use transition path sampling (TPS) with normal mode centroid molecular dynamics (CMD) to calculate the barrier to hydride transfer in yeast alcohol dehydrogenase (YADH) and lactate dehydrogenase (LDH). Calculation of the work applied to the hydride during the reaction allows for observation of the change in barrier height due to inclusion of quantum effects. Additionally, the same calculations were performed using deuterium as the transferring particle to validate our methods with experimentally measured kinetic isotope effects. The change in barrier height in YADH upon inclusion of quantum effects is indicative of a zero-point energy contribution, and is evidence that the protein mediates a near-barrierless transfer of the rate-limiting hydride. Calculation of kinetic isotope effects using the average difference in barrier between hydride and deuteride agreed well with experimental results. The authors acknowledge the support of the National Institutes of Health Grants GM068036 and GM102226.
9. Hydrogen transmission/storage with a metal hydride/organic slurry
Energy Technology Data Exchange (ETDEWEB)
Breault, R.W.; Rolfe, J.; McClaine, A. [Thermo Power Corp., Waltham, MA (United States)
1998-08-01
Thermo Power Corporation has developed a new approach for the production, transmission, and storage of hydrogen. In this approach, a chemical hydride slurry is used as the hydrogen carrier and storage media. The slurry protects the hydride from unanticipated contact with moisture in the air and makes the hydride pumpable. At the point of storage and use, a chemical hydride/water reaction is used to produce high-purity hydrogen. An essential feature of this approach is the recovery and recycle of the spent hydride at centralized processing plants, resulting in an overall low cost for hydrogen. This approach has two clear benefits: it greatly improves energy transmission and storage characteristics of hydrogen as a fuel, and it produces the hydrogen carrier efficiently and economically from a low cost carbon source. The preliminary economic analysis of the process indicates that hydrogen can be produced for $3.85 per million Btu based on a carbon cost of$1.42 per million Btu and a plant sized to serve a million cars per day. This compares to current costs of approximately $9.00 per million Btu to produce hydrogen from$3.00 per million Btu natural gas, and $25 per million Btu to produce hydrogen by electrolysis from$0.05 per Kwh electricity. The present standard for production of hydrogen from renewable energy is photovoltaic-electrolysis at $100 to$150 per million Btu.
10. Cool-down induced hydride reorientation of hydrogen-charged Zirconium alloy cladding tubes
International Nuclear Information System (INIS)
250 and 500ppm hydrogen-charged Zirconium alloy tubes were employed to investigate hydride reorientation behaviors when they were cool down from 400 to 300, 200degC and room temperature with various cooling rates of 0.3, 2.0, 4.0, 7.0 and 15.0degC/min under a tensile hoop stress of 150MPa. These cool-down tests indicate that the slower cooling rate and the lower terminal cool-down temperature produced the more hydrides precipitated along with the larger fraction and the longer length of radial hydrides. These phenomena may be explained by terminal solid solubility of hydrogen for dissolution and precipitation and cooling rate-dependent hydride nucleation and growth rates. On the other hand, a dramatic decrease of ultimate tensile strength and plastic strain of the cool-down tested specimens may be explained by the amount of the radial hydrides precipitated during the cool-down process. (author)
11. Hydrides blister formation and induced embrittlement on zircaloy-4 cladding tubes in reactivity initiated conditions
International Nuclear Information System (INIS)
Our aim is to study the cladding fracture with mechanical tests more representative of RIA conditions, taking into account the hydrides blisters, representative strain rates and stress states. To obtain hydride blisters, we developed a thermodiffusion setup that reproduces blister growth in reactor conditions. By metallography, nano-hardness, XRD and ERDA, we showed that they are constituted by 80% to 100% of δ hydrides in a Zircaloy-4 matrix, and that the zirconium beneath has some radially oriented hydrides. We modeled the blister growth kinetics taking into account the hysteresis of the hydrogen solubility limit and defined the thermal gradient threshold for blister growth. The modeling of the dilatometric behavior of hydrided zirconium indicates the important role of the material crystallographic texture, which could explain differences in the blister shape. Mechanical tests monitored with an infrared camera showed that significant local heating occurred at strain rates higher than 0.1/s. In parallel, the Expansion Due to Compression test was optimized to increase the bi-axiality level from uniaxial stress to plane strain (HB-EDC and VHB-EDC tests). This increase in loading bi-axiality lowers greatly the fracture strain at 25 C and 350 C only in homogeneous material without blister. Eventually, the ductility decrease of unirradiated Zircaloy-4 cladding tube in function of the blister depth was quantified. (author)
12. Nuclear quadrupole interaction studies of C15 RMn2 hydrides ( R=Y ,Gd,Tb,Dy)
Science.gov (United States)
Forker, M.; Bedi, S. C.; Euler, H.
2008-09-01
The nuclear electric quadrupole interaction (QI) of the probe nucleus I111n/C111d in the paramagnetic phase of the C15 rare earth (R) manganese hydrides (deuterides) RMn2H(D)x , with R=Y , Gd, Tb, and Dy, has been investigated by perturbed angular-correlation spectroscopy. The QI between the C111d quadrupole moment and the electric-field gradient (EFG) at the probe nucleus on the Mn site has been measured as a function of temperature in TbMn2H(D)x in the concentration range 0≤x≤4.3 and in RMn2H(D)x , R=Y ,Gd,Dy at the highest H content of xtilde 4.3 . The relative temperature dependence of the EFG in the parent compounds RMn2 is twice as strong as in isostructural RAl2 which can be related to differences in the Debye temperatures resulting from different radius ratios rR/rMn and rR/rAl [Joseph-Gschneidner postulate, Scr. Metall.2, 631 (1968)]. Hydrogenation of RMn2 increases the magnitude of the EFG by a factor of 2 between x=0 and x=4.3 but leaves the relative temperature dependence almost unchanged. Only at concentrations x>3.6 the temperature coefficient of the QI is significantly larger than in uncharged RMn2 . These results are compared with the much stronger concentration dependence and the anomalous temperature dependence of the QI of C111d in the C15 hydrides HfV2Hx . Evidence for an exceptionally high H mobility in TbMn2Hx is presented. The measurements provide information on structural changes and magnetic ordering temperatures at different H concentrations.
13. 75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...
Science.gov (United States)
2010-11-18
... in the Federal Register on November 17, 2009 (74 FR 59254). At the request of the State agency and a... Employment and Training Administration Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood... Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division, including on- site...
14. Investigation of Corrosion Behavior Of 6013 Aluminum Alloys For Artificial Aged Microwave Furnace
Directory of Open Access Journals (Sweden)
Muzaffer Erdoğan
2014-01-01
Full Text Available Low density and high strength aluminum alloys can be achieved today is a type of an alloy. These alloys are more resistant, particularly the aging process is the precipitate formed. In this study, increased strength 6013 aluminum alloy in a microwave furnace yaşlandırarak artificial. Volume samples in a microwave oven aging method and aging has provided a homogeneous way.6013 aluminum alloys, pure argon gas atmosphere in a microwave furnace hardness after being subjected to artificial aging process analysis, the internal structure (optical microscope, SEM, characterization of the studied. Aging of the phases, the presence server in the XRD of the samples was determined by curves. Corrosion of artificial aged samples has been analyzed by the internal structure of the phases present. Depending on the time of artificial aging of aluminum alloy 6013 samples in a microwave furnace in the mechanical properties of the sediment affected the corrosion resistance values.
15. Optical frequency comb generation from aluminum nitride micro-ring resonator
CERN Document Server
Jung, Hojoong; Fong, King Y; Zhang, Xufeng; Tang, Hong X
2013-01-01
Aluminum nitride is an appealing nonlinear optical material for on-chip wavelength conversion. Here we report optical frequency comb generation from high quality factor aluminum nitride micro-ring resonators integrated on silicon substrates. By engineering the waveguide structure to achieve near-zero dispersion at telecommunication wavelengths and optimizing the phase matching for four-wave mixing, frequency combs are generated with a single wavelength continuous-wave pump laser. The Kerr coefficient (n2) of aluminum nitride is further extracted from our experimental results.
16. Preparation and characterization of morph-genetic aluminum nitride/carbon composites from filter paper
International Nuclear Information System (INIS)
Morph-genetic aluminum nitride/carbon composites with cablelike structure were prepared from filter paper template through the surface sol-gel process and carbothermal nitridation reaction. The resulting materials have a hierarchical structure originating from the morphology of cellulose paper. The aluminum nitride/carbon composites have the core-shell microstructure, the core is graphitic carbon, and the shell is aluminum nitride nanocoating formed by carbothermal nitridation reduction of alumina with the interfacial carbon in nitrogen atmosphere. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscope were employed to characterize the structural morphology and phase compositions of the final products
17. Evaluation of Aluminum in Iranian Consumed Tea
OpenAIRE
Alireza Asgari; Mahdi Ahmadi Moghaddam; Amirhossein Mahvi; Masoud Yonesian
2008-01-01
Introduction: Black tea leaf is one of the most important sources of Aluminum in dietary. Therefore this research was conducted to assess the amount of Aluminum in Iranian tea infusion. Methods: To assess Aluminum in Iranian consumed tea, 27 tea samples were analyzed for Al concentration for 10 and 60 min infusion, aluminum concentration was measured with atomic absorption and the results were analyzed by SPSS.13 version. Results: The results showed that minimum and maximum concentration of A...
18. Mineral resource of the month: aluminum
Science.gov (United States)
Bray, E. Lee
2012-01-01
The article offers information on aluminum, a mineral resource which is described as the third-most abundant element in Earth's crust. According to the article, aluminum is the second-most used metal. Hans Christian Oersted, a Danish chemist, was the first to isolate aluminum in the laboratory. Aluminum is described as lightweight, corrosion-resistant and an excellent conductor of electricity and heat.
19. Electrochemical Behavior of Aluminum in Nitric Acid
Institute of Scientific and Technical Information of China (English)
CHEN; Hui; ZHU; Li-yang; LIN; Ru-shan; TAN; Hong-bin; HE; Hui
2013-01-01
Aluminum is one of cladding materials for nuclear fuel,it is important to investigate the electrolytic dissolution of aluminum in nitric acid.The electrochemical impedance spectroscopy,polarization curve and cyclic voltammetry cure of anodic aluminum electrode in nitric acid under various conditions were collected(Fig.1).It turns out,under steady state,the thickness of the passivated film of aluminum
20. Dehydrogenation kinetics for pure and nickel-doped magnesium hydride investigated by in-situ, time-resolved powder diffraction (poster)
DEFF Research Database (Denmark)
Jensen, T.R.; Andreasen, A.; Vegge, T.;
2004-01-01
The dehydrogenation kinetics of pure and nickel-doped magnesium hydride was investigated by in-situ, time-resolved X-ray powder diffraction. A special reaction cell allowed the study of gas/solid reactions and analysis of the exhaust gas by massspectroscopy. X-ray data (0 <2è <120°) was collected...... under isothermal conditions with a time resolution of 45 s. Three phases were identified, Mg,MgH2 and MgO, and the phase fractions were extracted for each phase. Dehydrogenation curves wereconstructed and analyzed by the Johnson-Mehl-Avrami formalism in order to derive rateconstants at different....... Furthermore, the difference in apparent activation energy of ca. 50 kJ/mol compares totheoretical calculations for the atomisation of H2 molecules, which might be the rate-determining step in the dehydrogenation process.... | {"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": 0.6654464602470398, "perplexity": 7249.114564099067}, "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-2017-22/segments/1495463608084.63/warc/CC-MAIN-20170525140724-20170525160724-00201.warc.gz"} |
http://accessanesthesiology.mhmedical.com/content.aspx?bookid=974§ionid=61587807 | Chapter 51
### PHYSIOLOGY
Opioids are a class of endogenous, naturally occurring, and synthetic compounds that primarily provide analgesia. The effects of opioids are generated at an array of receptors found in peripheral, spinal cord, and brain tissues. Individual opioid receptors may be responsible for analgesia, muscle rigidity, depressed respiratory drive, bradycardia, hypotension, constipation, urinary retention, nausea, and sedation, to name several important clinical effects.
Pain is transmitted via a three-neuron system that originates at the periphery and ends at the cerebral cortex. At periphery tissues, noxious stimuli are mainly received and transmitted by A beta, A delta, and C fiber neurons. These first-order neurons synapse with second-order neurons in the dorsal horn of the spinal cord level. Second-order neurons travel up the spinal cord via the dorsal column and spinothalamic tract and synapse with third-order neurons at the thalamus, which then transmit signals to the cerebral cortex, the site of pain perception. Opioids exert their effects at receptors at all three levels of this system.
### SPECIFIC PAIN MEDIATORS
Tissue injury at peripheral tissue causes the release of many different chemical mediators responsible for pain and physical changes at the site of injury. A host of major pain-inducing mediators originate from activated cells at the site of injury.
• Bradykinin—Originating from macrophages and plasma kininogen, this mediator activates nociceptors.
• Serotonin—Originating from platelets, this mediator activates nociceptors.
• Histamine—Originating from platelets and mast cells, this mediator causes vasodilation, edema, and pruritis.
• Prostaglandin—Originating from the cyclooxygenase (COX) pathway, this mediator sensitizes nociceptors.
• Leukotriene—Originating from the lipoxygenase pathway, this mediator sensitizes nociceptors.
• H+ ions—Originating from tissue injury and ischemia, this mediator causes hyperalgesia associated with inflammation.
• Cytokines (tumor necrosis factor [TNF], interleukins)—Originating from macrophages, these mediators sensitize nociceptors.
• Adenosine—Originating from tissue injury, this mediator activates nociceptors and causes hyperalgesia.
• Glutamate—Originating from injured nerve terminals, this mediator activates nociceptors.
• Substance P—Originating from injured nerve terminals, this mediator activates macrophages and mast cells.
• Nerve growth factor—originating from macrophages, this mediator stimulates mast cells to release histamine and serotonin.
These pain mediators signal various receptors located throughout the three-neuron pain signal system. The transmitted signal travels to the cerebral cortex and is perceived as pain. Opioid therapy aims to block or attenuate a nociception signal by activating receptors that counter signal transmission. The major receptors activated by opioids are mu, delta, and kappa. These are G-coupled receptors, which carry the mediator-induced signal in conjunction with a second messenger such as cyclic adenosine monophosphate (cAMP). They are located at the periphery, the dorsal horn of the spinal cord, and finally the brainstem, thalamus, and cortex. At these locations, the three major mechanisms of action are:
1. Inhibition of presynaptic Ca2+ influx, which depolarizes the cell and inhibits the release of neurotransmitters at the synaptic cleft.
2. Increasing postsynaptic K+ efflux, which depolarizes and inhibits ...
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Connect to the full suite of AccessAnesthesiology content and resources including procedural videos, interactive self-assessment, real-life cases, 20+ textbooks, and more | {"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": 0.15991319715976715, "perplexity": 16190.163551889325}, "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-2017-13/segments/1490218189031.88/warc/CC-MAIN-20170322212949-00373-ip-10-233-31-227.ec2.internal.warc.gz"} |
http://www.thecodingforums.com/threads/what-is-the-best-html-to-latex-program-on-the-market-or-the-internet.546177/ | # What is the best html to latex program on the market or the internet ?
Discussion in 'HTML' started by vasan999@hotmail.com, Oct 22, 2007.
1. ### Guest
Basically, it should do all that any of the tools below and in
1/
human readable output that maintains the text lines of the source, ie
does not scramble the text lines or insert newlines unnecessarily or
removes them. inserts minimal latex elements.
2/
maintains cross-links, ie convert <href to \ref and <name= to \label
but if the set of htmls is incomplete proceed with the assumption that
the reference is there, ie dont delete the links or try to modify them
or their addresses. One of the tool I tested is too smart in this
respect and actually ruins the result.
3/
proper conversion of images, tables, etc. No math mode involved in
html.
4/
Even an emacs lisp function could be written by a guru that can do the
job.
5/
Is there any commercial wysiwig tool ?
LaTeX etc
* html2latex is a program based on the NCSA html parser. Contact:
.
* Another html2latex can combine several HTML files into a single
LaTeX file, converting links between the files to references. External
URL's can be converted into footnotes or into a bibliography sorted on
URL. Contact: (Frans J. Faase)
* Another html2latex implemented on Linux by yacc+lex+C. Also
available from the TSX-11 Linux FTP site as nc-html2latex-0.97.tar.gz.
Contact: (Naoya Tozuka)
* htmlatex.pl is a perl script to do the conversion (may be moving
soon). Contact: (Jake Kesinger)
* There is also a sed script to convert HTML into LaTeX.
, Oct 22, 2007
2. ### Guest
The site says, that this will convert html to latex. Can anyone
explain me this
code? I am not familiar with such difficult commands especially there
are no
comments line by line explanation and overall operation.
1i\
\\documentstyle{article}
1i\
\\begin{document}
$a\ \\end{document} # Too bad there's no way to make sed ignore case! /<[Xx][Mm][Pp]>/,/<.[Xx][Mm][Pp]>/b lit /<.[Xx][Mm][Pp]>/b lit /<[Ll][Ii][Ss][Tt][Ii][Nn][Gg]>/,/<.[Ll][Ii][Ss][Tt][Ii][Nn][Gg]>/b lit /<.[Ll][Ii][Ss][Tt][Ii][Nn][Gg]>/b lit /<[Pp][Rr][Ee]>/,/<.[Pp][Rr][Ee]>/b pre /<.[Pp][Rr][Ee]>/b pre # Stuff to ignore s?<[Ii][Ss][Ii][Nn][Dd][Ee][Xx]>?? s?</[Aa][Dd][Dd][Rr][Ee][Ss][Ss]>??g s?<[Nn][Ee][Xx][Tt][Ii][Dd][^>]*>??g # character set translations for LaTex special chars s?>.?>?g s?<.?<?g s?\\?\\backslash ?g s?{?\\{?g s?}?\\}?g s?%?\\%?g s?\$?\\$?g s?&?\\&?g s?#?\\#?g s?_?\\_?g s?~?\\~?g s?\^?\\^?g # Paragraph borders s?<[Pp]>?\\par ?g s?</[Pp]>??g # Headings s?<[Tt][Ii][Tt][Ll][Ee]>$$[^<]*$$</[Tt][Ii][Tt][Ll][Ee]>?\ \section*{\1}?g s?<[Hh]n>?\\part{?g s?</[Hh]n>?}?g s?<[Hh]1>?\\section*{?g s?</[Hh][0-9]>?}?g s?<[Hh]2>?\\subsection*{?g s?<[Hh]3>?\\subsubsection*{?g s?<[Hh]4>?\\subsubsection*{?g s?<[Hh]5>?\\paragraph{?g s?<[Hh]6>?\\subparagraph{?g # UL is itemize s?<[Uu][Ll]>?\\begin{itemize}?g s?</[Uu][Ll]>?\\end{itemize}?g s?<[Ll][Ii]>?\\item ?g # DL is description s?<[Dd][Ll]>?\\begin{description}?g s?</[Dd][Ll]>?\\end{description}?g # closing delimiter for DT is first < or end of line which ever comes first NO #s?<[Dd][Tt]>$$[^<]*$$<?\\item[\1]<?g #s?<[Dd][Tt]>$$[^<]*$$$?\\item[\1]?g
#s?<[Dd][Dd]>??g
s?<[Dd][Tt]>?\\item[<?g
s?<[Dd][Dd]>?]?g
# Other common SGML markup. this is ad-hoc
s?<sec[ab]>??
s?</sec[ab]>??g
# Italics
s?<it>$$[^<]*$$</it>?{\\it \1 }?g
# Get rid of Anchors
re
s?<[Aa][^>]*>??g
s?</[Aa]>??g
# This is a subroutine in sed, in case you are not a sed guru
: lit
s?<[Xx][Mm][Pp]>?\\begin{verbatim}?g
s?</[Xx][Mm][Pp]>?\\end{verbatim}?
s?<[Ll][Ii][Ss][Tt][Ii][Nn][Gg]>?\\begin{verbatim}?g
s?</[Ll][Ii][Ss][Tt][Ii][Nn][Gg]>?\\end{verbatim}?
On Oct 22, 2:57 pm, wrote:
> Basically, it should do all that any of the tools below and in
>
> 1/
> human readable output that maintains the text lines of the source, ie
> does not scramble the text lines or insert newlines unnecessarily or
> removes them. inserts minimal latex elements.
>
> 2/
> maintains cross-links, ie convert <href to \ref and <name= to \label
>
> but if the set of htmls is incomplete proceed with the assumption that
> the reference is there, ie dont delete the links or try to modify them
> or their addresses. One of the tool I tested is too smart in this
> respect and actually ruins the result.
>
> 3/
> proper conversion of images, tables, etc. No math mode involved in
> html.
>
> 4/
> Even an emacs lisp function could be written by a guru that can do the
> job.
>
> 5/
> Is there any commercial wysiwig tool ?
>
> LaTeX etc
>
> * html2latex is a program based on the NCSA html parser. Contact:
> .
> * Another html2latex can combine several HTML files into a single
> LaTeX file, converting links between the files to references. External
> URL's can be converted into footnotes or into a bibliography sorted on
> URL. Contact: (Frans J. Faase)
> * Another html2latex implemented on Linux by yacc+lex+C. Also
> available from the TSX-11 Linux FTP site as nc-html2latex-0.97.tar.gz.
> Contact: (Naoya Tozuka)
> * htmlatex.pl is a perl script to do the conversion (may be moving
> soon). Contact: (Jake Kesinger)
> * There is also a sed script to convert HTML into LaTeX.
, Oct 23, 2007
3. ### Guest
maybe I should post in european tex groups also
On Oct 22, 2:57 pm, wrote:
> Basically, it should do all that any of the tools below and in
>
> 1/
> human readable output that maintains the text lines of the source, ie
> does not scramble the text lines or insert newlines unnecessarily or
> removes them. inserts minimal latex elements.
>
> 2/
> maintains cross-links, ie convert <href to \ref and <name= to \label
>
> but if the set of htmls is incomplete proceed with the assumption that
> the reference is there, ie dont delete the links or try to modify them
> or their addresses. One of the tool I tested is too smart in this
> respect and actually ruins the result.
>
> 3/
> proper conversion of images, tables, etc. No math mode involved in
> html.
>
> 4/
> Even an emacs lisp function could be written by a guru that can do the
> job.
>
> 5/
> Is there any commercial wysiwig tool ?
>
> LaTeX etc
>
> * html2latex is a program based on the NCSA html parser. Contact:
> .
> * Another html2latex can combine several HTML files into a single
> LaTeX file, converting links between the files to references. External
> URL's can be converted into footnotes or into a bibliography sorted on
> URL. Contact: (Frans J. Faase)
> * Another html2latex implemented on Linux by yacc+lex+C. Also
> available from the TSX-11 Linux FTP site as nc-html2latex-0.97.tar.gz.
> Contact: (Naoya Tozuka)
> * htmlatex.pl is a perl script to do the conversion (may be moving
> soon). Contact: (Jake Kesinger)
> * There is also a sed script to convert HTML into LaTeX.
, Oct 23, 2007
4. ### Edd BarrettGuest
On Oct 23, 2:26 am, wrote:
> maybe I should post in european tex groups also
>
> On Oct 22, 2:57 pm, wrote:
>
> > Basically, it should do all that any of the tools below and in
>
> > 1/
> > human readable output that maintains the text lines of the source, ie
> > does not scramble the text lines or insert newlines unnecessarily or
> > removes them. inserts minimal latex elements.
>
> > 2/
> > maintains cross-links, ie convert <href to \ref and <name= to \label
>
> > but if the set of htmls is incomplete proceed with the assumption that
> > the reference is there, ie dont delete the links or try to modify them
> > or their addresses. One of the tool I tested is too smart in this
> > respect and actually ruins the result.
>
> > 3/
> > proper conversion of images, tables, etc. No math mode involved in
> > html.
>
> > 4/
> > Even an emacs lisp function could be written by a guru that can do the
> > job.
>
> > 5/
> > Is there any commercial wysiwig tool ?
>
> > LaTeX etc
>
> > * html2latex is a program based on the NCSA html parser. Contact:
> > .
> > * Another html2latex can combine several HTML files into a single
> > LaTeX file, converting links between the files to references. External
> > URL's can be converted into footnotes or into a bibliography sorted on
> > URL. Contact: (Frans J. Faase)
> > * Another html2latex implemented on Linux by yacc+lex+C. Also
> > available from the TSX-11 Linux FTP site as nc-html2latex-0.97.tar.gz.
> > Contact: (Naoya Tozuka)
> > * htmlatex.pl is a perl script to do the conversion (may be moving
> > soon). Contact: (Jake Kesinger)
> > * There is also a sed script to convert HTML into LaTeX.
Hi,
I don't know if this can be of help:
http://openwetware.org/wiki/User:Austin_J._Che/Extensions/LatexDoc
This is something that we are looking into to allow researchers to
distribute documents in both PDF and web-based (we hope).
Thanks
Edd
Edd Barrett, Oct 23, 2007
5. ### metaperl.comGuest
I like PlasTeX.SF.Net
> Basically, it should do all that any of the tools below and in
metaperl.com, Oct 23, 2007
6. ### Guest
On Oct 23, 11:13 am, "metaperl.com" <> wrote:
> I like PlasTeX.SF.Net
>
> > Basically, it should do all that any of the tools below and in
I think OP wanted html->latex
http://plastex.sourceforge.net/
SAS is currently using plasTeX to generate HTML and DocBook for
10,000+ pages of scientific documentation nightly.
, Oct 23, 2007
7. ### Peter FlynnGuest
Re: What is the best html to latex program on the market or the internet?
wrote:
> The site says, that this will convert html to latex. Can anyone
> explain me this code? I am not familiar with such difficult commands
> especially there are no comments line by line explanation and overall
> operation.
>
> 1i\
> \\documentstyle{article}
[snip]
This is a sed(1) script. sed is a stream editor, available on most
platforms.
///Peter
Peter Flynn, Oct 23, 2007
8. ### Peter FlynnGuest
Re: What is the best html to latex program on the market or the internet?
wrote:
> Basically, it should do all that any of the tools below and in
didn't see it...
XSLT.
Run your HTML through Tidy to produce XHTML.
Then write an XSLT script to transform it to LaTeX.
This gives you 100% control and ensures robustness.
However, handling all the stupid things HTML authors do may make it
long-winded if you want to cope with them all. On the other hand, if
you are dealing with a reasonably consistent subset, it's probably the
most reliable method.
///Peter
Peter Flynn, Oct 23, 2007
9. ### Guest
On Oct 23, 3:27 pm, Peter Flynn <> wrote:
> wrote:
> > Basically, it should do all that any of the tools below and in
>
> didn't see it...
>
> XSLT.
>
> Run your HTML through Tidy to produce XHTML.
> Then write an XSLT script to transform it to LaTeX.
> This gives you 100% control and ensures robustness.
>
> However, handling all the stupid things HTML authors do may make it
> long-winded if you want to cope with them all. On the other hand, if
> you are dealing with a reasonably consistent subset, it's probably the
> most reliable method.
>
> ///Peter
forgot to cc to myself.
Janusz
, Oct 24, 2007
10. ### Victor IvriiGuest
On Oct 23, 6:27 pm, Peter Flynn <> wrote:
> wrote:
> > Basically, it should do all that any of the tools below and in
>
> didn't see it...
>
> XSLT.
>
> Run your HTML through Tidy to produce XHTML.
> Then write an XSLT script to transform it to LaTeX.
> This gives you 100% control and ensures robustness.
>
> However, handling all the stupid things HTML authors do may make it
> long-winded if you want to cope with them all. On the other hand, if
> you are dealing with a reasonably consistent subset, it's probably the
> most reliable method.
One should remember that while tex parser (tex/latex/...) can run in
quiet mode, it is not a default and finished tex document normally
does not contain any tex errors. Meanwhile few html parsers (web
html sources contain errors, from few to few hundreds (the latter is
the case usually with commercial web pages, produced by community
colleges graduates, who check their pages only against a specific
version of MSIE). The task of converting of such html sources to error-
free tex ones seems to be a really daunting
>
> ///Peter
Victor Ivrii, Oct 24, 2007
11. ### tsyGuest
On Oct 24, 5:27 am, Peter Flynn <> wrote:
> wrote:
> Run your HTML through Tidy to produce XHTML.
> Then write an XSLT script to transform it to LaTeX.
> This gives you 100% control and ensures robustness.
Is XSLT way easier than using a decent scripting language with a SAX
library?
tsy, Oct 24, 2007
12. ### Peter FlynnGuest
Re: What is the best html to latex program on the market or theinternet ?
On Wed, 24 Oct 2007 08:21:29 -0700, tsy wrote:
> On Oct 24, 5:27 am, Peter Flynn <> wrote:
>> wrote:
>> Run your HTML through Tidy to produce XHTML. Then write an XSLT script
>> to transform it to LaTeX. This gives you 100% control and ensures
>> robustness.
> Is XSLT way easier than using a decent scripting language with a SAX
> library?
Yes. XSLT *is* a decent scripting (well, transformation-to-other-formats)
language.
///Peter
Peter Flynn, Oct 27, 2007
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Oct 30, 2007 | {"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": 0.6771200299263, "perplexity": 13405.957507487095}, "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-2015-40/segments/1443736680773.55/warc/CC-MAIN-20151001215800-00195-ip-10-137-6-227.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/simple-pendulum-acceleration.284653/ | # Homework Help: Simple pendulum acceleration
1. Jan 13, 2009
### chopstick
For a simple pendulum practice with clamp, boss head and resort stand assembled, also a string attached to the end of clamp and a bob, then swings it and measure the time for it to complete a period.
At the end use the information collected to calculate acceleration due to the gravity by the formula g = 4π2l/T2.
What could the accuracy and reliability be effected? (Equipments, angles or the error should avoid) And what kind of string or bob will most suit? Why?
2. Jan 13, 2009
### mgb_phys
Welcome to PF.
For HW questions you have to make some sort of attempt before we can help.
To get you started, if a quantity is squared would that make any error in that quantity worse or better?
3. Jan 14, 2009
### chopstick
i think that will make it worse. so i measured the period for it complete ten oscillations and repeat it with different length of strings, due that both of them are the only variables in the equation. Even L and T are the only variables, but the angle should some how involved, would it?
and also for the string and 'bob', only thing i can think of was the air resistance, anything else that i should think about?
sorry for didn't show enough effort, i thought that could make the question simple. i just something else that can increase the accuracy and reliability in that practise. just looking for some hint
Last edited: Jan 14, 2009
4. Jan 14, 2009
### mgb_phys
There are two types of error to consider .
1, You are trying to use an ideal law for the period - no friction, all the weight acts at L etc.
So you want your experiment to be as close to the imaginary ideal as possible and reduce effects like.
Air friction on the string (do you want a big swing or small ?)
All the mass to be at distance L (so the string must be much lighter than the bob)
No friction where the string pivots.
2, There is also propagation of errors - which is what I hinted at.
The answer is proportional to L so an error in L will give the same percentage error in 'g'
But 't' is squared so an error in 't'gives a bigger error in 'g' - so you have to put more effort into measuring 't' accurately than you do into measuring 'L'
5. Jan 15, 2009
### chopstick
thank you for your help, i been confuse for whiles.
6. Jan 15, 2009
### Identity
What if you square a quantity between -1 and 1? Doesn't the error decrease?
7. Jan 15, 2009
### chopstick
damn! i cannot understand it, what does between -1 and 1 mean | {"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": 0.8057918548583984, "perplexity": 1269.1106753179909}, "config": {"markdown_headings": true, "markdown_code": false, "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-2018-26/segments/1529267863939.76/warc/CC-MAIN-20180620221657-20180621001657-00035.warc.gz"} |
http://corochann.com/page/3 | # AtCoder Regular Contest 063 review
Link ARC 063 top page Editorial C – 一次元リバーシ / 1D Reversi Problem
D – 高橋君と見えざる手 / An Invisible Hand Problem I didn’t notice that there is a restriction that each $$A_i$$ is different. So it took time for implementation.
E – 木と整数 / Integers on a Tree Problem Follow editorial.
# Codeforces Round #378 Div. 2 review
Link Codeforces Round #378 Div. 2 (Contest 733) A. Grasshopper And the String Link: Problem Category: Implementation Even this is a first problem, I get wrong answer for first time submission. It is necessary to consider a corner case at the “end of the text”. Some other solution is inserting extra ‘A’ at the end of text so that you can handle it in the same way. (ex. latte0119’s solution)
B. Parade Link: Problem Category: math Below implementation is a little bit optimized solution for not to use memory of $$O(N)$$, but use $$O(1)$$. But in the contest, it is better to consider solve it as fast as possible rather […]
# Codeforces Round #377 Div. 2 review
Link Codeforces Round #377 Div. 2 (Contest 732) A. Buy a Shovel Problem It can be paid without change if the change is 0 or $$r$$.
B. Cormen — The Best Friend Of a Man Problem At day $$i$$, dog need to walk $$k-a[i-1]$$ times.
C. Sanatorium Problem Basic idea to the solution is not difficult, just check all the popssibility of what time start eating (enter room) and what time end eating (exit room). But the corner case handling makes this problem difficult and I cannot answer correctly in one time. Rather than below, more elegant/ short code solution can be found at pekempey’s solution.
D. Exams […]
# AtCoder Regular Contest 062 review
Link ARC 062 top page Editorial C – AtCoDeerくんと選挙速報 / AtCoDeer and Election Report Problem
D – AtCoDeerくんと変なじゃんけん / AtCoDeer and Rock-Paper Problem
E – AtCoDeerくんと立方体づくり / Building Cubes with AtCoDeer Problem Implementation based on Editorial.
# Topcoder SRM 699 Div2 review
Single Round Match 699 Sponsored by Cisco Statistics – Problem Editorial Div II Level One: UpDownHiking Idea is same with editorial.
Div II Level Two: LastDigit Category: Arithmetric The approach is different from editorial which uses binary search.
Div II Level Three: FromToDivisibleDiv2 Category: Arithmetric, graph I couldn’t solve it in contest, so I just followed editorial for my practice.
# Codeforces Round #374 Div. 2 review
Link Codeforces Round #374 Div. 2 (Contest 721) Editorial A. One-dimensional Japanese Crossword Problem Just count consecutive ‘B’ in the sequence.
B. Passwords Problem This is also easy, just count the number for each string length. You even don’t need to process any string manipulation.
C. Journey Problem I felt it is difficult than problem D. During the contest, I tried to solve it by DFS but I got TLE.
To get answer, we can use DP (dynamic programming) to reduce computational complexity as $$O(mn)$$.
D. Maxim and Array Problem Basic strategy to get minimum product is as follows, 1. If the product is positive, […]
# Codeforces Round #373 Div. 2 review
Link Codeforces Round #373 Div. 2 (Contest 719) A. Vitya in the Countryside Problem Basically, check last 2 character to determine its direction is “UP” or “DOWN”. Special case comes when the last number is 0 or 15, in that case the direction changes and you can determine the direction without looking second last character.
B. Anatoly and Cockroaches Problem We can consider 2 patterns for final alignment. Pattern 0 is to align “rbrbrb…” and pattern 1 is to align “brbrbr…”. We will compare the original alignment and final alignment. For each position i, we need to change the color to… Case A: r to b Case B: b to r If […]
# Codeforces Round #368 Div. 2 review
Link Codeforces Round #368 Div. 2 (Contest 707) A. Brain’s Photos Problem Just need to check if color (Cyan, Magenta or Yellow) exists or not in the photo.
B. Bakery Problem The problem sentence looks long, but after summarize, you just need to find the path between flour storage city and non flour storage city with minimum distance. But to find out these city path, I was using vector which is not fast enough and I got TLE during contest.
We can make search fast, in constant time by using Array to set a type of city.
C. Pythagorean Triples Problem Consider some cases to […]
# scanf and printf are much faster than cin and cout
When I’m solving the Codeforces problem, 707D. Persistent Bookcase, I made some comparison for the performance of I/O function. scanf() and printf() cin >> and cout << Test Let’s start from C++ common way, below code uses cin >> and cout <<
It took 748 ms. Next, (old-school,) C way of implementation using scanf() and printf()
It took only 171 ms. Result function time scanf() and printf() 171 ms cin >> and cout << 748 ms In this experiment, it appears that the speed of cin and cout is much much slower than scanf() and printf(), the difference is indeed quite huge. The overhead of cin and cout took more than 500 ms! You might get a […]
D: Digit Sum – 桁和 I came up different approach from editorial. Let $$a_i$$ be $$i$$-th digit with base $$b$$. Then, $$n = \sum_i b^i a_i$$ $$s = f(b, n) = \sum_i a_i$$ applies. If we subtract these equation, we obtain $$n – s = \sum_i (b^i – 1) a_i$$ Both side should be integer, and right hand side […] | {"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": 0.2545584738254547, "perplexity": 4512.593099866464}, "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-2017-22/segments/1495463607802.75/warc/CC-MAIN-20170524055048-20170524075048-00424.warc.gz"} |
http://math.stackexchange.com/questions/73649/algorithm-for-solving-sparse-equality-constrained-least-squares | # Algorithm for solving sparse equality-constrained least squares
I have a diagonal, positive-definite inner product matrix $M$ and want to find a minimizer of
$$\min_q \frac{1}{2} \|q-q_0\|_M^2\qquad \text{s.t.}\qquad C^Tq+c_0 = 0,$$
where $q_0, c_0$, and $C$ are given and $C$ is very large and sparse.
What is the best algorithm for efficiently solving this problem? The straightforward approach is to solve the normal equations $$\left[\begin{array}{cc}M & C\\C^T & 0\end{array}\right]\left[\begin{array}{c}q\\ \lambda\end{array}\right] = \left[\begin{array}{c} Mq_0 \\-c_0\end{array}\right]$$ for $q$; the matrix here is sparse and symmetric, but indefinite and possibly singular, so sparse iterative solvers like good old Conjugate Gradient cannot be used.
A little manipulation of the above gives an alternative two-step approach where you solve first for the Lagrange multipliers: $$C^T M^{-1} C\lambda = C^Tq_0 + c_0$$ and then substitute $\lambda$ into $$q = q_0 - M^{-1} C\lambda.$$ Since $M$ is diagonal it is trivial to invert, and $C^T M^{-1} C$ is symmetric positive-(semi)definite, but is dense and so also is inefficient to solve when the number of constraints is very large.
What is the standard approach to solving this problem?
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"the matrix here is sparse and symmetric, but indefinite and possibly singular, so sparse iterative solvers like good old Conjugate Gradient cannot be used" - right, that's where things like MINRES(-QLP) come in... – J. M. Oct 18 '11 at 14:56
Thanks, that looks promising – user7530 Oct 18 '11 at 15:50
J.M. is correct that the difficulty is that C does not necessarily have full column rank, causing your augmented system to be singular. The standard approach in this case would be to regularize your problem, i.e., replace the constraint $C^T q + c_0 = 0$ with $C^T q + \delta r + c_0 = 0$ for some small value of $\delta > 0$ (e.g., between $10^{-6}$ and $10^{-8}$) and a new variable $r$ representing the residual of your constraints. Your constraint matrix is now $$\begin{bmatrix} C^T & \delta I \end{bmatrix}$$ which always has full row rank. At the same time, you'll want to add a term $\delta^2 \|r\|^2$ to your objective so as to minimize this residual.
If everything is nonsingular, you have several options to solve the problem. One is a symmetric indefinite factorization of the augmented system (the one you call the "normal equations"). This can be done very efficiently and in parallel, if the system is so large. In Matlab, look into the lbl function. In Fortran, look into the HSL library: http://www.hsl.rl.ac.uk/academic.html (the relevant packages are MA27, MA47, MA57 and MA86).
Regarding iterative methods, aside from MINRES, you can also try SYMMLQ if the system is nonsingular. See Mike Saunders' website for links to those codes: http://www.stanford.edu/group/SOL/software.html
There is an alternative if you have a means to identify efficiently a particular solution $\bar{q}_0$ of $C^T q + c_0 = 0$ (by factorization or using some special structure of the problem). You can "shift" your linear system by defining $\bar{q} := q - \bar{q}_0$: $$\begin{bmatrix} M & C \\ C^T & 0 \end{bmatrix} \begin{bmatrix} \bar{q} \\ \lambda \end{bmatrix} = \begin{bmatrix} M(q_0 - \bar{q}_0) \\ 0 \end{bmatrix}.$$ These are the optimality conditions of the (unconstrained) linear least-squares problem $$\min_{\lambda} \ \tfrac{1}{2} \| C \lambda - M(q_0 - \bar{q}_0) \|_{M^{-1}}^2.$$ NOW you can use the conjugate gradients, or better yet, LSQR (still from Michael Saunders' page). LSQR is a variant of CG which will be more accurate if $C$ is ill conditioned. Once you have found $\lambda$, you can recover $\bar{q} = q_0 - \bar{q}_0 - M^{-1} C \lambda$ and your solution is $q = \bar{q} + \bar{q}_0$.
For more general $M$ (non diagonal), there is a nice hybrid alternative. It consists in interpreting the shifted linear systems as the optimality conditions of the quadratic program $$\min_{\bar{q}} \ -(q_0 - \bar{q}_0)^T M \bar{q} + \tfrac{1}{2} \bar{q}^T M \bar{q} \quad \text{s.t.} \ C^T \bar{q} = 0.$$ The method is a hybrid between a factorization and CG. It needs to factorize the matrix $$\begin{bmatrix} I & C \\ C^T & 0 \end{bmatrix}$$ and applies CG to $M$. At each iteration, the search direction is projected into the nullspace of $C^T$, ensuring that all iterates satisfy $C^T \bar{q} = 0$. The main reference is http://epubs.siam.org/sisc/resource/1/sjoce3/v23/i4/p1376_s1
Clearly, for diagonal $M$, there's no advantage versus a direct factorization of your original system. But in many applications, replacing $M$ by $I$ leads to a very sparse matrix. Also $M$ need not be positive definite any more but only positive definite on the nullspace of $C^T$.
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http://paperity.org/search/?q=authors%3A%22Andrzej+Borowiec%22 | # Search: authors:"Andrzej Borowiec"
3 papers found.
Use AND, OR, NOT, +word, -word, "long phrase", (parentheses) to fine-tune your search.
#### Starobinsky cosmological model in Palatini formalism
We classify singularities in FRW cosmologies, which dynamics can be reduced to the dynamical system of the Newtonian type. This classification is performed in terms of the geometry of a potential function if it has poles. At the sewn singularity, which is of a finite scale factor type, the singularity in the past meets the singularity in the future. We show that such singularities ...
#### Do sewn up singularities falsify the Palatini cosmology?
We investigate further (cf. Borowiec et al. JCAP 1601(01):040, 2016) the Starobinsky cosmological model $R+\gamma R^2$ in the Palatini formalism with a Chaplygin gas and baryonic matter as a source in the context of singularities. The dynamics reduces to the 2D sewn dynamical system of a Newtonian type (a piece-wise-smooth dynamical system). We demonstrate that the presence of a ...
#### Yang-Baxter sigma models and Lax pairs arising from κ-Poincaré r-matrices
We study Yang-Baxter sigma models with deformed 4D Minkowski spacetimes arising from classical r-matrices associated with κ-deformations of the Poincaré algebra. These classical κ-Poincaré r-matrices describe three kinds of deformations: 1) the standard deformation, 2) the tachyonic deformation, and 3) the light-cone deformation. For each deformation, the metric and two-form ... | {"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": 0.7391760349273682, "perplexity": 2527.179507499164}, "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-2017-34/segments/1502886107490.42/warc/CC-MAIN-20170821041654-20170821061654-00004.warc.gz"} |
https://orbilu.uni.lu/browse?type=author&value=Iovino,%20Vincenzo%2050002024 | References of "Iovino, Vincenzo 50002024" in Complete repository Arts & humanities Archaeology Art & art history Classical & oriental studies History Languages & linguistics Literature Performing arts Philosophy & ethics Religion & theology Multidisciplinary, general & others Business & economic sciences Accounting & auditing Production, distribution & supply chain management Finance General management & organizational theory Human resources management Management information systems Marketing Strategy & innovation Quantitative methods in economics & management General economics & history of economic thought International economics Macroeconomics & monetary economics Microeconomics Economic systems & public economics Social economics Special economic topics (health, labor, transportation…) Multidisciplinary, general & others Engineering, computing & technology Aerospace & aeronautics engineering Architecture Chemical engineering Civil engineering Computer science Electrical & electronics engineering Energy Geological, petroleum & mining engineering Materials science & engineering Mechanical engineering Multidisciplinary, general & others Human health sciences Alternative medicine Anesthesia & intensive care Cardiovascular & respiratory systems Dentistry & oral medicine Dermatology Endocrinology, metabolism & nutrition Forensic medicine Gastroenterology & hepatology General & internal medicine Geriatrics Hematology Immunology & infectious disease Laboratory medicine & medical technology Neurology Oncology Ophthalmology Orthopedics, rehabilitation & sports medicine Otolaryngology Pediatrics Pharmacy, pharmacology & toxicology Psychiatry Public health, health care sciences & services Radiology, nuclear medicine & imaging Reproductive medicine (gynecology, andrology, obstetrics) Rheumatology Surgery Urology & nephrology Multidisciplinary, general & others Law, criminology & political science Civil law Criminal law & procedure Criminology Economic & commercial law European & international law Judicial law Metalaw, Roman law, history of law & comparative law Political science, public administration & international relations Public law Social law Tax law Multidisciplinary, general & others Life sciences Agriculture & agronomy Anatomy (cytology, histology, embryology...) & physiology Animal production & animal husbandry Aquatic sciences & oceanology Biochemistry, biophysics & molecular biology Biotechnology Entomology & pest control Environmental sciences & ecology Food science Genetics & genetic processes Microbiology Phytobiology (plant sciences, forestry, mycology...) Veterinary medicine & animal health Zoology Multidisciplinary, general & others Physical, chemical, mathematical & earth Sciences Chemistry Earth sciences & physical geography Mathematics Physics Space science, astronomy & astrophysics Multidisciplinary, general & others Social & behavioral sciences, psychology Animal psychology, ethology & psychobiology Anthropology Communication & mass media Education & instruction Human geography & demography Library & information sciences Neurosciences & behavior Regional & inter-regional studies Social work & social policy Sociology & social sciences Social, industrial & organizational psychology Theoretical & cognitive psychology Treatment & clinical psychology Multidisciplinary, general & others Showing results 1 to 20 of 21 1 2 Non-interactive Zero Knowledge Proofs in the Random Oracle ModelIovino, Vincenzo ; Visconti, Ivanin Codes, Cryptology and Information Security (2019)The Fiat-Shamir (FS) transform is a well known and widely used technique to convert any constant-round public-coin honest-verifier zero-knowledge (HVZK) proof or argument system CIPC=(Prov,Ver) in a non ... [more ▼]The Fiat-Shamir (FS) transform is a well known and widely used technique to convert any constant-round public-coin honest-verifier zero-knowledge (HVZK) proof or argument system CIPC=(Prov,Ver) in a non-interactive zero-knowledge (NIZK) argument system NIZK=(NIZK.Prove, NIZK.Verify). The FS transform is secure in the random oracle (RO) model and is extremely efficient: it adds an evaluation of the RO for every message played by Ver. While a major effort has been done to attack the soundness of the transform when the RO is instantiated with a secure'' hash function, here we focus on a different limitation of the FS transform that exists even when there is a secure instantiation of the random oracle: the soundness of NIZK holds against polynomial-time adversarial provers only. Therefore even when CIPC is a proof system, NIZK is only an argument system. In this paper we propose a new transform from 3-round public-coin HVZK proof systems for several practical relations to NIZK proof systems in the RO model. Our transform outperforms the FS transform protecting the honest verifier from unbounded adversarial provers with no restriction on the number of RO queries. The protocols our transform can be applied to are the ones for proving membership to the range of a one-way group homomorphism as defined by [Maurer - Design, Codes and Cryptography 2015] except that we additionally require the function to be endowed with a trapdoor and other natural properties. For instance, we obtain new efficient instantiations of NIZK proofs for relations related to quadratic residuosity and the RSA function. As a byproduct, with our transform we obtain essentially for free the first efficient non-interactive zap (i.e., 1-round non-interactive witness indistinguishable proof system for several practical languages in the non-programmable RO model and in an ideal-PUF model. Our approach to NIZK proofs can be seen as an abstraction of the celebrated work of [Feige, Lapidot and Shamir - FOCS 1990]. [less ▲]Detailed reference viewed: 123 (7 UL) On the Relation Between SIM and IND-RoR Security Models for PAKEs with Forward SecrecyLopez Becerra, José Miguel ; Iovino, Vincenzo ; Ostrev, Dimiter et alin E-Business and Telecommunications - 2019 (2019)Password-based Authenticated Key-Exchange (PAKE) protocols allow the establishment of secure communication entirely based on the knowledge of a shared password. Over the last two decades, we have ... [more ▼]Password-based Authenticated Key-Exchange (PAKE) protocols allow the establishment of secure communication entirely based on the knowledge of a shared password. Over the last two decades, we have witnessed the debut of a number of prominent security models for PAKE protocols, whose aim is to capture the desired security properties that such protocols must satisfy when executed in the presence of an active adversary. These models are usually classified into (i) indistinguishability-based (IND-based) or (ii) simulation-based (SIM-based). However, the relation between these two security notions is unclear and mentioned as a gap in the literature. In this work, we prove that SIM-BMP security from Boyko et al. (EUROCRYPT 2000) implies IND-RoR security from Abdalla et al. (PKC 2005) and that IND-RoR security is equivalent to a slightly modified version of SIM-BMP security. We also investigate whether IND-RoR security implies (unmodified) SIM-BMP security. The results obtained also hold when forward secrecy is incorporated into the security models in question. [less ▲]Detailed reference viewed: 157 (10 UL) Tightly-Secure PAK(E)Lopez Becerra, José Miguel ; Iovino, Vincenzo ; Ostrev, Dimiter et alin Cryptology and Network Security (2017, December 02)We present a security reduction for the PAK protocol instantiated over Gap Diffie-Hellman Groups that is tighter than previously known reductions. We discuss the implications of our results for concrete ... [more ▼]We present a security reduction for the PAK protocol instantiated over Gap Diffie-Hellman Groups that is tighter than previously known reductions. We discuss the implications of our results for concrete security. Our proof is the first to show that the PAK protocol can provide meaningful security guarantees for values of the parameters typical in today’s world. [less ▲]Detailed reference viewed: 237 (36 UL) Using Selene to Verify your Vote in JCJIovino, Vincenzo ; Rial, Alfredo ; Roenne, Peter et alin Workshop on Advances in Secure Electronic Voting (VOTING'17) (2017, April 07)Detailed reference viewed: 305 (31 UL) On the Relation Between SIM and IND-RoR Security Models for PAKEsLopez Becerra, José Miguel ; Iovino, Vincenzo ; Skrobot, Marjan Presentation (2017, March 09)Security models for PAKE protocols aim to capture the desired security properties that such protocols must satisfy when executed in the presence of an active adversary. They are usually classified into i ... [more ▼]Security models for PAKE protocols aim to capture the desired security properties that such protocols must satisfy when executed in the presence of an active adversary. They are usually classified into i) indistinguishability-based (IND-based) or ii) simulation-based (SIM-based). The relation between these two security notions is unclear and mentioned as a gap in the literature. In this work, we prove that the SIM-based model of Boyko, Mackenzie and Patel [EUROCRYPT00] and the IND-based model of Abdalla, Fouque and Pointcheval are equivalent, in the sense that a protocol proven secure in one model is also secure in the other model. [less ▲]Detailed reference viewed: 129 (3 UL) Receiver and Sender Deniable Functional EncryptionDe Caro, Angelo; Iovino, Vincenzo ; O'Neill, Adamin IET Information Security (2017)Deniable encryption, first introduced by Canetti et al. (CRYPTO 1997), allows equivocation of encrypted communication. In this work we generalize its study to functional encryption (FE). Our results are ... [more ▼]Deniable encryption, first introduced by Canetti et al. (CRYPTO 1997), allows equivocation of encrypted communication. In this work we generalize its study to functional encryption (FE). Our results are summarized as follows: We first put forward and motivate the concept of receiver deniable FE, for which we consider two models. In the first model, as previously considered by O'Neill et al. (CRYPTO 2011) in the case of identity-based encryption, a receiver gets assistance from the master authority to generate a fake secret key. In the second model, there are normal'' and deniable'' secret keys, and a receiver in possession of a deniable secret key can produce a fake but authentic-looking normal key on its own. In the first model, we show a compiler from any FE scheme for the general circuit functionality to a FE scheme having receiver deniability. In addition we show an efficient receiver deniable FE scheme for Boolean Formulae from bilinear maps. In the second (multi-distributional) model, we present a specific FE scheme for the general circuit functionality having receiver deniability. To our knowledge, a scheme in the multi-distributional model was not previously known even for the special case of identity-based encryption. Finally, we construct the first sender (non-multi-distributional) deniable FE scheme. [less ▲]Detailed reference viewed: 275 (5 UL) Privacy-Preserving Verifiability: A Case for an Electronic Exam ProtocolGiustolisi, Rosario; Iovino, Vincenzo ; Lenzini, Gabriele in Giustolisi, Rosario; Iovino, Vincenzo; Lenzini, Gabriele (Eds.) Privacy-Preserving Verifiability: A Case for an Electronic Exam Protocol (2017)We introduce the notion of privacy-preserving verifiability for security protocols. It holds when a protocol admits a verifiability test that does not reveal, to the verifier that runs it, more pieces of ... [more ▼]We introduce the notion of privacy-preserving verifiability for security protocols. It holds when a protocol admits a verifiability test that does not reveal, to the verifier that runs it, more pieces of information about the protocol’s execution than those required to run the test. Our definition of privacy-preserving verifiability is general and applies to cryptographic protocols as well as to human security protocols. In this paper we exemplify it in the domain of e-exams. We prove that the notion is meaningful by studying an existing exam protocol that is verifiable but whose verifiability tests are not privacy-preserving. We prove that the notion is applicable: we review the protocol using functional encryption so that it admits a verifiability test that preserves privacy to our definition. We analyse, in ProVerif, that the verifiability holds despite malicious parties and that the new protocol maintains all the security properties of the original protocol, so proving that our privacy-preserving verifiability can be achieved starting from existing security. [less ▲]Detailed reference viewed: 243 (18 UL) On the power of Public-key Function-Private Functional EncryptionIovino, Vincenzo ; Tang, Qiang; Zebrowski, Karolin IET Information Security (2017)In the public-key setting, known constructions of function-private functional encryption (FPFE) were limited to very restricted classes of functionalities like inner-product [Agrawal et al. - PKC 2015 ... [more ▼]In the public-key setting, known constructions of function-private functional encryption (FPFE) were limited to very restricted classes of functionalities like inner-product [Agrawal et al. - PKC 2015]. Moreover, its power has not been well investigated. In this paper, we construct FPFE for general functions and explore its powerful applications, both for general and specific functionalities. One key observation entailed by our results is that Attribute-based Encryption with function privacy implies FE, a notable fact that sheds light on the importance of the function privacy property for FE. [less ▲]Detailed reference viewed: 174 (6 UL) On the Relation Between SIM and IND-RoR Security Models for PAKEsLopez Becerra, José Miguel ; Iovino, Vincenzo ; Ostrev, Dimiter et alin Proceedings of the International Conference on Security and Cryptography (2017)Password-based Authenticated Key-Exchange (PAKE) protocols allow users, who need only to share a password, to compute a high-entropy shared session key despite passwords being taken from a dictionary ... [more ▼]Password-based Authenticated Key-Exchange (PAKE) protocols allow users, who need only to share a password, to compute a high-entropy shared session key despite passwords being taken from a dictionary. Security models for PAKE protocols aim to capture the desired security properties that such protocols must satisfy when executed in the presence of an active adversary. They are usually classified into i) indistinguishability-based (IND-based) or ii) simulation-based (SIM-based). The relation between these two security notions is unclear and mentioned as a gap in the literature. In this work, we prove that SIM-BMP security from Boyko et al.~(EUROCRYPT 2000) implies IND-RoR security from Abdalla et al.~(PKC 2005) and that IND-RoR security implies a slightly modified version of SIM-BMP security. We also investigate whether IND-RoR security implies (unmodified) SIM-BMP security. [less ▲]Detailed reference viewed: 286 (16 UL) Controlled Homomorphic Encryption: Definition and ConstructionDesmedt, Yvo; Iovino, Vincenzo ; Persiano, Giuseppe et alin FC 2017 International Workshops - WAHC'17 - 5th Workshop on Encrypted Computing and Applied Homomorphic Cryptography (2017)In this work we put forth the notion of a Controllable Homomorphic Encryption scheme (CHES), a new primitive that includes features of both FHEs and FunctEs. In a CHES it is possible (similarly to a FHE ... [more ▼]In this work we put forth the notion of a Controllable Homomorphic Encryption scheme (CHES), a new primitive that includes features of both FHEs and FunctEs. In a CHES it is possible (similarly to a FHE) to homomorphically evaluate a ciphertext Ct = Enc(m) and a circuit C therefore obtaining Enc(C(m)) but only if (similarly to a FunctE) a token for C has been received from the owner of the secret key. We discuss difficulties in constructing a CHES and then show a construction based on any FunctE. As a byproduct our CHES also represents a FunctE supporting the re-encryption functionality and in that respect improves existing solutions. [less ▲]Detailed reference viewed: 243 (7 UL) Updatable Functional EncryptionDelerue Arriaga, Afonso ; Iovino, Vincenzo ; Tang, Qiangin Paradigms in Cryptology - Mycrypt 2016. Malicious and Exploratory Cryptology, Second International Conference, Mycrypt 2016, Kuala Lumpur, Malaysia, December 1-2, 2016, Revised Selected Papers (2016, December)Functional encryption (FE) allows an authority to issue tokens associated with various functions, allowing the holder of some token for function f to learn only f(D) from a ciphertext that encrypts D. The ... [more ▼]Functional encryption (FE) allows an authority to issue tokens associated with various functions, allowing the holder of some token for function f to learn only f(D) from a ciphertext that encrypts D. The standard approach is to model f as a circuit, which yields inefficient evaluations over large inputs. Here, we propose a new primitive that we call updatable functional encryption (UFE), where instead of circuits we deal with RAM programs, which are closer to how programs are expressed in von Neumann architecture. We impose strict efficiency constrains in that the run-time of a token P' on ciphertext CT is proportional to the run-time of its clear-form counterpart (program P on memory D) up to a polylogarithmic factor in the size of D, and we envision tokens that are capable to update the ciphertext, over which other tokens can be subsequently executed. We define a security notion for our primitive and propose a candidate construction from obfuscation, which serves as a starting point towards the realization of other schemes and contributes to the study on how to compute RAM programs over public-key encrypted data. [less ▲]Detailed reference viewed: 311 (12 UL) On the Possibility of Non-Interactive E-Voting in the Public-key SettingGiustolisi, Rosario; Iovino, Vincenzo ; Rønne, Peterin Financial Cryptography and Data Security, FC 2016 International Workshops, BITCOIN, VOTING, and WAHC, Christ Church, Barbados, February 26, 2016, Revised Selected Papers (2016)In 2010 Hao, Ryan and Zielinski proposed a simple decentralized e-voting protocol that only requires 2 rounds of communication. Thus, for k elections their protocol needs 2k rounds of communication ... [more ▼]In 2010 Hao, Ryan and Zielinski proposed a simple decentralized e-voting protocol that only requires 2 rounds of communication. Thus, for k elections their protocol needs 2k rounds of communication. Observing that the first round of their protocol is aimed to establish the public-keys of the voters, we propose an extension of the protocol as a non-interactive e-voting scheme in the public-key setting (NIVS) in which the voters, after having published their public-keys, can use the corresponding secret-keys to participate in an arbitrary number of one-round elections. We first construct a NIVS with a standard tally function where the number of votes for each candidate is counted. Further, we present constructions for two alternative types of elections. Specifically in the first type (dead or alive elections) the tally shows if at least one voter cast a vote for the candidate. In the second one (elections by unanimity), the tally shows if all voters cast a vote for the candidate. Our constructions are based on bilinear groups of prime order. As definitional contribution we provide formal computational definitions for privacy and verifiability of NIVSs. We conclude by showing intriguing relations between our results, secure computation, electronic exams and conference management systems [less ▲]Detailed reference viewed: 200 (17 UL) On the power of Public-key Function-Private Functional EncryptionIovino, Vincenzo ; Tang, Qiang ; Zebrowski, Karolin 15th International Conference on Cryptology and Network Security (2016)In the public-key setting, known constructions of function-private functional encryption (FPFE) were limited to very restricted classes of functionalities like inner-product [Agrawal et al. - PKC 2015 ... [more ▼]In the public-key setting, known constructions of function-private functional encryption (FPFE) were limited to very restricted classes of functionalities like inner-product [Agrawal et al. - PKC 2015]. Moreover, its power has not been well investigated. In this paper, we construct FPFE for general functions and explore its powerful applications, both for general and specific functionalities. As warmup, we construct from FPFE a natural generalization of a signature scheme endowed with functional properties, that we call functional anonymous signature (FAS) scheme. In a FAS, Alice can sign a circuit C chosen from some distribution D to get a signature s and can publish a verification key that allows anybody holding a message m to verify that (1) s is a valid signature of Alice for some (possibly unknown to him) circuit C and (2) C(m)=1. Beyond unforgeability the security of FAS guarantees that the signature s hide as much information as possible about C except what can be inferred from knowledge of D. Then, we show that FPFE can be used to construct in a black-box way functional encryption schemes for randomized functionalities (RFE). %Previous constructions of (public-key) RFE relied on iO [Goyal et al. - TCC 2015]. As further application, we show that specific instantiations of FPFE can be used to achieve adaptively-secure CNF/DNF encryption for bounded degree formulae (BoolEnc). Though it was known how to implement BoolEnc from inner-product encryption (IPE) [Katz et al. - EUROCRYPT 2008], as already observed by Katz et al. this reduction only works for selective security and completely breaks down for adaptive security; however, we show that the reduction works if the IPE scheme is function-private. Finally, we present a general picture of the relations among all these related primitives. One key observation is that Attribute-based Encryption with function privacy implies FE, a notable fact that sheds light on the importance of the function privacy property for FE. [less ▲]Detailed reference viewed: 211 (13 UL) On the Power of Rewinding Simulators in Functional EncryptionDe Caro, Angelo; Iovino, Vincenzo in Designs, Codes and Cryptography (2016)In a seminal work, Boneh, Sahai and Waters (BSW, for short) [TCC'11] showed that for functional encryption the indistinguishability notion of security (IND-Security) is weaker than simulation-based ... [more ▼]In a seminal work, Boneh, Sahai and Waters (BSW, for short) [TCC'11] showed that for functional encryption the indistinguishability notion of security (IND-Security) is weaker than simulation-based security (SIM-Security), and that SIM-Security is in general impossible to achieve. This has opened up the door to a plethora of papers showing feasibility and new impossibility results. Nevertheless, the quest for better definitions that (1) overcome the limitations of IND-Security and (2) the known impossibility results, is still open. In this work, we explore the benefits and the limits of using {\em efficient rewinding black-box simulators} to argue security. To do so, we introduce a new simulation-based security definition, that we call {\em rewinding simulation-based security} (RSIM-Security), that is weaker than the previous ones but it is still sufficiently strong to not meet pathological schemes as it is the case for IND-Security (that is implied by the RSIM). This is achieved by retaining a strong simulation-based flavour but adding more rewinding power to the simulator having care to guarantee that it can not learn more than what the adversary would learn in any run of the experiment. What we found is that for RSIM the BSW impossibility result does not hold and that IND-Security is {\em equivalent} to RSIM-Security for {\em Attribute-Based Encryption} in the {\em standard model}. Nevertheless, we prove that there is a setting where rewinding simulators are of no help. The adversary can put in place a strategy that forces the simulator to rewind continuously. [less ▲]Detailed reference viewed: 187 (15 UL) Deniable Functional EncryptionDe caro, Angelo; Iovino, Vincenzo ; O'Neill, Adamin Public-key Cryptography - PKC 2016, 19th IACR International Conference on Practice and Theory in Public-Key Cryptography, Taipei, Taiwan, March 6-9, 2016, Proceedings, Part I (2016)Deniable encryption, first introduced by Canetti et al. (CRYPTO 1997), allows a sender and/or receiver of encrypted communication to produce fake but authentic-looking coins and/or secret keys that “open” ... [more ▼]Deniable encryption, first introduced by Canetti et al. (CRYPTO 1997), allows a sender and/or receiver of encrypted communication to produce fake but authentic-looking coins and/or secret keys that “open” the communication to a different message. Here we initiate its study for the more general case of functional encryption (FE), as introduced by Boneh et al. (TCC 2011), wherein a receiver in possession of a key k can compute from any encryption of a message x the value F (k, x) according to the scheme’s functionality F . Our results are summarized as follows: We put forth and motivate the concept of deniable FE, for which we consider two models. In the first model, as previously considered by O’Neill et al. (CRYPTO 2011) in the case of identity-based encryption, a receiver gets assistance from the master authority to generate a fake secret key. In the second model, there are “normal” and “deniable” secret keys, and a receiver in possession of a deniable secret key can produce a fake but authentic-looking normal key on its own. This parallels the “multi-distributional” model of deniability previously considered for public-key encryption. In the first model, we show that any FE scheme for the general circuit functionality (as several recent candidate construction achieve) can be converted into an FE scheme having receiver deniability, without introducing any additional assumptions. In addition we show an efficient receiver deniable FE for Boolean Formulae from bilinear maps. In the second (multi-distributional) model, we show a specific FE scheme for the general circuit functionality having receiver deniability. This result additionally assumes differing-inputs obfuscation and relies on a new technique we call delayed trapdoor circuits. To our knowledge, a scheme in the multi-distributional model was not previously known even in the simpler case of identity-based encryption. Finally, we show that receiver deniability for FE implies some form of simulation security, further motivating study of the latter and implying optimality of our results. [less ▲]Detailed reference viewed: 292 (21 UL) (Universal) Unconditional Verifiability in E-Voting without Trusted PartiesGallegos-Garcia, Gina; Iovino, Vincenzo ; Roenne, Peter et alE-print/Working paper (2016)Detailed reference viewed: 242 (4 UL) Mergeable Functional EncryptionIovino, Vincenzo ; Żebrowski, KarolScientific Conference (2015, September 11)Detailed reference viewed: 139 (12 UL) Selene: Voting with Transparent Verifiability and Coercion-MitigationRyan, Peter ; Roenne, Peter ; Iovino, Vincenzo in Abstract book of 1st Workshop on Advances in Secure Electronic Voting (2016), 2015Detailed reference viewed: 521 (61 UL) Simulation-Based Secure Functional Encryption in the Random Oracle ModelIovino, Vincenzo ; Żebrowski, Karolin Progress in Cryptology -- LATINCRYPT 2015 (2015)One of the main lines of research in functional encryption (FE) has consisted in studying the security notions for FE and their achievability. This study was initiated by [Boneh et al. – TCC’11, O’Neill – ... [more ▼]One of the main lines of research in functional encryption (FE) has consisted in studying the security notions for FE and their achievability. This study was initiated by [Boneh et al. – TCC’11, O’Neill – ePrint’10] where it was first shown that for FE the indistinguishability-based (IND) security notion is not sufficient in the sense that there are FE schemes that are provably IND-Secure but concretely insecure. For this reason, researchers investigated the achievability of Simulation-based (SIM) security, a stronger notion of security. Unfortunately, the above-mentioned works and others [e.g., Agrawal et al. – CRYPTO’13] have shown strong impossibility results for SIM-Security. One way to overcome these impossibility results was first suggested in the work of Boneh et al. where it was shown how to construct, in the Random Oracle (RO) model, SIM-Secure FE for restricted functionalities and was asked the generalization to more complex functionalities as a challenging problem in the area. Subsequently, [De Caro et al. – CRYPTO’13] proposed a candidate construction of SIM-Secure FE for all circuits in the RO model assuming the existence of an IND-Secure FE scheme for circuits with RO gates. To our knowledge there are no proposed candidate IND-Secure FE schemes for circuits with RO gates and they seem unlikely to exist. We propose the first constructions of SIM-Secure FE schemes in the RO model that overcome the current impossibility results in different settings. We can do that because we resort to the two following models: In the public-key setting we assume a bound on the number of queries but this bound only affects the running-times of our encryption and decryption procedures. We stress that our FE schemes in this model are SIM-Secure and have ciphertexts and tokens of constant-size, whereas in the standard model, the current SIM-Secure FE schemes for general functionalities [De Caro et al., Gorbunov et al. – CRYPTO’12] have ciphertexts and tokens of size growing as the number of queries. In the symmetric-key setting we assume a timestamp on both ciphertexts and tokens. In this model, we provide FE schemes with short ciphertexts and tokens that are SIM-Secure against adversaries asking an unbounded number of queries. Both results also assume the RO model, but not functionalities with RO gates and rely on extractability obfuscation [Boyle et al. – TCC’14] (and other standard primitives) secure only in the standard model. [less ▲]Detailed reference viewed: 280 (5 UL) On the Possibility of Non-Interactive E-Voting in the Public-key SettingGiustolisi, Rosario; Iovino, Vincenzo ; Roenne, Peter in IACR Cryptology ePrint Archive (2015), 2015Detailed reference viewed: 185 (8 UL) 1 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": 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": 0.7199904322624207, "perplexity": 4888.555787772716}, "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/1679296950030.57/warc/CC-MAIN-20230401125552-20230401155552-00651.warc.gz"} |
https://learnzillion.com/lesson_plans/7199-choose-a-sampling-method-given-a-situation | # Choose a sampling method given a situation
teaches Common Core State Standards CCSS.Math.Content.HSS-IC.A.1 http://corestandards.org/Math/Content/HSS/IC/A/1
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Card of | {"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": 0.9547585844993591, "perplexity": 12869.51147489586}, "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-2017-30/segments/1500549436321.71/warc/CC-MAIN-20170728022449-20170728042449-00040.warc.gz"} |
https://www.physicsforums.com/threads/analytic-functions.519384/ | # Analytic functions
1. Aug 5, 2011
### tibphysic
(3+x-iy)^7 is analytic function of the complex variable z=x+iy in the domain [z]<2?
2. Aug 5, 2011
### BackEMF
Nope, $$f(z) = (3+x-iy)^7 = (3+\bar{z})^7$$
$$\frac{df}{d\bar{z}} = 7(3+\bar{z})^6 \neq 0, \,\mathrm{for}\; |z| < 2.$$ | {"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": 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": 0.8507415652275085, "perplexity": 24882.320036660756}, "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/1531676593004.92/warc/CC-MAIN-20180722022235-20180722042235-00122.warc.gz"} |
https://www.astro.gla.ac.uk/users/eduard/cesra/?paged=4 | ### Harvest of scientific results by Solar Orbiter Radio and Plasma Waves instrument by Milan Maksimovic
2022-02-15
For a mission that has just entered its primary science phase, Solar Orbiter has already produced many remarkable results. Released on December 14, 2021, a special issue of Astronomy and Astrophysics brings together a wealth of studies and observations obtained during the mission’s cruise phase. Of the 56 articles published, 25 are based on data from the Radio & Plasma Waves (RPW) instrument (Maksimovic et al., A&A, 2020). The RPW […]
### Signatures of Type III Solar Radio Bursts from Nanoflares: Modeling by Sherry Chhabra et al.*
2022-02-01
Nanoflares are impulsive energy releases due to small breaks in coronal magnetic fields that have become stressed by photospheric convection. They are too small to be detected individually, but several lines of evidence suggest that they may be a primary candidate of coronal heating. But, whether nanoflares excite particles like full-sized flares is unknown (Vievering et al. 2021). A leading theory of particle acceleration predicts that the efficiency of acceleration […]
### Radio Probing of Solar Wind Sources in Coronal Magnetic Fields by A. Koval et al.*
2022-01-18
The magnetic fields of the Sun govern the solar corona structure where the solar wind emanates and further accelerates supersonically. Therefore, the accurate observational data about the topology, and more significantly, quantities of the coronal magnetic field are pivotal for identifying the solar wind sources as well as for the Space Weather modeling where these data specify initial conditions. Magnetic-field strength values in the solar wind sources are derived from […]
### Characterising coronal turbulence using snapshot imaging of radio bursts in 80 – 200 MHz by Atul Mohan
2022-01-04
Metrewave solar type-III radio bursts offer a unique means to study the properties of turbulence across coronal heights. Theoretical models have shown that the apparent intensity and size of the burst sources evolve at sub-second scales due to turbulent scattering of radio waves close to their generation sites (Arzner & Magun, 1999; Kontar et al., 2019). The advent of high cadence snapshot spectroscopic imaging capabilities in meter wavebands have made […]
### Particle-in-cell simulation of plasma emission in solar radio bursts by T. M. Li et al.
2021-12-21
Solar radio radiation is one of the most sensitive emissions during solar eruptions, where type III radio bursts can provide clues for electron acceleration and propagation. Type III radio bursts are widely accepted to result from the plasma emission, which is observationally supported by the presence of Langmuir waves, and excited electromagnetic waves at fundamental and harmonic frequencies from the nonlinear wave coupling (Ginzburg & Zhelezniakov 1958). Such a mechanism […]
### Searching for optical/EUV counterparts of type IIs in a complex metric burst
by Costas Alissandrakis et al.*
2021-12-07
Solar type II bursts are sporadic emissions characterized by their narrow bandwidth and slow frequency drift in dynamic spectra (Nelson & Melrose, 1985; Vršnak & Cliver 2008; Nindos et al. 2008; Pick & Vilmer 2008). They are attributed to shock waves produced by flare/CME eruptions. However, the association of type IIs with optical or EUV features is not clear; the leading edge or flanks of CMEs, the front of an […]
### PIC simulations of harmonic maser emissions by Ning et al.*
2021-11-23
Electron cyclotron maser emission (ECME) represents a major class of coherent emission mechanism of solar radio bursts. ECME usually occurs in strongly magnetized plasmas with the frequency ratio $\omega_{pe} / \Omega_{ce} < 1$, induced by energetic electrons with $\partial f /\partial v >0$, where $f$ represents the velocity distribution function. In solar active regions, this mechanism has been applied to millisecond spikes which are characterized by high brightness temperatures, short […]
### Radio Interferometric Observations of the Sun Using Commercial Dish TV Antennas by G. V. S. Gireesh et al.*
2021-11-09
Commercial dish TV antennas are parabolic structures designed to receive radio waves from a communication satellite. The antennas and the associated front end receiver systems have improved with advances in the TV systems. They operate typically over the frequency range 10.7 – 11.7 GHz (Ku-band) and provide very good signal-to-noise ratio (SNR). It is well known that the Sun emits intense radio emission in the above frequency range with brightness […] | {"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": 0.8237298727035522, "perplexity": 3090.475594294873}, "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/1679296949035.66/warc/CC-MAIN-20230329213541-20230330003541-00434.warc.gz"} |
http://en.wikipedia.org/wiki/Litterfall | # Plant litter
(Redirected from Litterfall)
Leaf litter, mainly White Beech, Gmelina leichhardtii, from Black Bulga State Conservation Area, NSW, Australia
Litterfall, plant litter, leaf litter, tree litter, soil litter, or duff, is dead plant material, such as leaves, bark, needles, and twigs, that has fallen to the ground. This detritus or dead organic material and its constituent nutrients are added to the top layer of soil, commonly known as the litter layer or O horizon ("O" for "organic"). Litter has occupied the attention of ecologists at length for the reasons that it is an instrumental factor in ecosystem dynamics, is indicative of ecological productivity, and may be useful in predicting regional nutrient cycling and soil fertility.
## Characteristics and variability
Plant litter, mainly western hemlock, Tsuga heterophylla, in Mount Baker-Snoqualmie National Forest, Washington state, USA.
Litterfall is characterized as fresh, undecomposed, and easily recognizable (by species and type) plant debris. This can be anything from leaves, cones, needles, twigs, bark, seeds/nuts, logs, or reproductive organs (e.g. the stamen of flowering plants). Items larger than 2 cm diameter are referred to as coarse litter, while anything smaller is referred to as fine litter or litter. The type of litterfall is most directly affected by ecosystem type. For example, leaf tissues account for about 70 percent of litterfall in forests, but woody litter tends to increase with forest age.[1] In grasslands, there is very little aboveground perennial tissue so the annual litterfall is very low and quite nearly equal to the net primary production.[2]
In soil science, soil litter is classified in three layers, which form on the surface of the O Horizon. These are the L, F, and H layers:[3]
• L - organic horizon characterized by relatively undecomposed plant material (described above).
• F - organic horizon found beneath L characterized by accumulation of partly decomposed organic matter.
• H - organic horizon below F characterized by accumulation of fully decomposed organic matter mostly indiscernible
The litter layer is quite variable in its thickness, decomposition rate and nutrient content and is affected in part by seasonality, plant species, climate, soil fertility, elevation, and latitude. The most extreme variability of litterfall is seen as a function of seasonality; each individual species of plant has seasonal losses of certain parts of its body, which can be determined by the collection and classification of plant litterfall throughout the year, and in turn affects the thickness of the litter layer. In tropical environments, the largest amount of debris falls in the latter part of dry seasons and early during wet season.[4] As a result of this variability due to seasons, the decomposition rate for any given area will also be variable.
Litter fall in the North American Baldcypress Swamp Network, Illinois to Louisiana, 2003[5]
Latitude also has a strong effect on litterfall rates and thickness. Specifically, litterfall declines with increasing latitude. In tropical rainforests, there is a thin litter layer due to the rapid decomposition,[6] while in boreal forests, the rate of decomposition is slower and leads to the accumulation of a thick litter layer, also known as a mor.[2] Net primary production works inversely to this trend, suggesting that the accumulation of organic matter is mainly a result of decomposition rate.
Surface detritus facilitates the capture and infiltration of rainwater into lower soil layers. Soil litter protects soil aggregates from raindrop impact, preventing the release of clay and silt particles from plugging soil pores.[7] Releasing clay and silt particles reduces the capacity for soil to absorb water and increases cross surface flow, accelerating soil erosion. In addition soil litter reduces wind erosion by preventing soil from losing moisture and providing cover preventing soil transportation.
Organic matter accumulation also helps protect soils from wildfire damage. Soil litter can be completely removed depending on intensity and severity of wildfires and season.[8] Regions will high frequency wildfires have reduced vegetation density and reduced soil litter accumulation. Climate also influences the depth of plant litter. Typically humid tropic and sub-tropic climates have reduced organic matter layers and horizons due to year round decomposition and high vegetation density and growth. In temperate and cold climates, litter tends to accuculate and decompose slower due to a shorter growing season.
## Net primary productivity
Net primary production and litterfall are intimately connected. In every terrestrial ecosystem, the largest fraction of all net primary production is lost to herbivores and litterfall. Therefore these factors must be accounted for. Ecologists account for this effect by subtracting the accumulated litterfall from the net primary production, resulting in what is called the true increment of net primary production. Due to their interconnectedness, global patterns of litterfall are similar to global patterns of net primary productivity.[2]
## Habitat and food
Litter provides habitat for a variety of organisms.
### Plants
Common wood sorrel (Oxalis acetosella) in Ivanovo Oblast, Russia
Certain plants are specially adapted for germinating and thriving in the litter layers. For example, bluebell (Hyacinthoides non-scripta) shoots puncture the layer to emerge in spring. Some plants with rhizomes, such as common wood sorrel (Oxalis acetosella) do well in this habitat.[6]
### Detritivores and other decomposers
Many organisms that live on the forest floor are decomposers, such as fungi. Organisms whose diet consists of plant detritus, such as earthworms, are termed detritivores. The community of decomposers in the litter layer also includes bacteria, amoeba, nematodes, rotifer, springtails, cryptostigmata, potworms, insect larvae, mollusks, oribatid mites, woodlice, and millipedes.[6] Their consumption of the litterfall results in the breakdown of simple carbon compounds into carbon dioxide (CO2) and water (H2O), and releases inorganic ions (like nitrogen and phosphorus) into the soil where the surrounding plants can then reabsorb the nutrients that were shed as litterfall. In this way, litterfall becomes an important part of the nutrient cycle that sustains forest environments.
As litter decomposes, nutrients are released into the environment. The portion of the litter that is not readily decomposable is known as humus. Litter aids in soil moisture retention by cooling the ground surface and holding moisture in decaying organic matter. The flora and fauna working to decompose soil litter also aid in soil respiration. A litter layer of decomposing biomass provides a continuous energy source for macro- and micro-organisms.[9]
A skink, Eutropis multifasciata, in leaf litter in Sabah, Malaysia
### Larger animals
Numerous reptiles, amphibians, birds, and even some mammals rely on litter for shelter and forage. For example, amphibians such as salamanders and caecilians inhabit the damp microclimate underneath fallen leaves for part or all of their life cycle. This makes them difficult to observe. A BBC film crew captured footage of a female caecilian with young for the first time in a documentary that aired in 2008.[10] Some species of birds require leaf litter both for foraging and as material used to construct nests, such as the ovenbird of eastern North America.[11] Sometimes litterfall even provides energy to much larger mammals, such as in boreal forests where lichen litterfall is one of the main constituents of wintering deer and elk diets.[12]
## Nutrient cycle
During leaf senescence, a portion of the plant’s nutrients are reabsorbed into the leaves. The nutrient concentrations in litterfall differ from the nutrient concentrations in the mature foliage by the reabsorption of constituents during leaf senescence.[2] Plants that grow in areas with low nutrient availability tend to produce litter with low nutrient concentrations, but a larger proportion of the available nutrients is reabsorbed. After senescence, the nutrient-enriched leaves become litterfall and settle on the soil below.
A budget for organic matter in a mature (120-year-old) Scots pine monoculture (SWECON site). Based on data from Andersson et al.(1980). Units are in kg of organic matter per ha. Att. -attached; Surf. -surface; min. -mineral; and veg. -vegetation[13]
Litterfall is the dominant pathway for nutrient return to the soil, especially for nitrogen (N) and phosphorus (P). The accumulation of these nutrients in the top layer of soil is known as soil immobilization. Once the litterfall has settled, decomposition of the litter layer, accomplished through the leaching of nutrients by rainfall and throughfall and by the efforts of detritivores, releases the breakdown products into the soil below and therefore contributes to the cation exchange capacity of the soil. This holds especially true for highly weathered tropical soils.[14]
Leaching is the process by which cations such as iron (Fe) and aluminum (Al), as well as organic matter are removed from the litterfall and transported downward into the soil below. This process is known as podzolization and is particularly intense in boreal and cool temperate forests that are mainly constituted by coniferous pines whose litterfall is rich in phenolic compounds and fulvic acid.[2]
By the process of biological decomposition by microfauna, bacteria, and fungi, CO2 and H2O, nutrient elements, and an exceedingly resistant organic compound called humus are released. Humus composes the bulk of organic matter in the lower soil profile.[2]
The decline of nutrient ratios is also a function of decomposition of litterfall (i.e. as litterfall decomposes, more nutrients enter the soil below and the litter will have a lower nutrient ratio). Litterfall containing high nutrient concentrations will decompose more rapidly and asymptote as those nutrients decrease.[15] Knowing this, ecologists have been able to use nutrient concentrations as measured by remote sensing as an index of a potential rate of decomposition for any given area.[16] Globally, data from various forest ecosystems shows an inverse relationship in the decline in nutrient ratios to the apparent nutrition availability of the forest.[2]
Once nutrients have re-entered the soil, the plants can then reabsorb them through their roots. Therefore, nutrient reabsorption during senescence presents an opportunity for a plant’s future net primary production use. A relationship between nutrient stores can also be defined as:
annual storage of nutrients in plant tissues + replacement of losses from litterfall and leaching = the amount of uptake in an ecosystem
## Collection and analysis
The main objectives of litterfall sampling and analysis are to quantify litterfall production and chemical composition over time in order to assess the variation in litterfall quantities, and hence its role in nutrient cycling across an environmental gradient of climate (moisture and temperature) and soil conditions.[17]
Ecologists employ a simple approach to the collection of litterfall, most of which centers around once piece of equipment, known as a litterbag. A litterbag is simply any type of container that can be set out in any given area for a specified amount of time to collect the plant litter that falls from the canopy above.
Litterfall and throughfall collectors at beech stand in Thetford, East Anglia[18]
Litterbags are generally set in random locations within a given area and marked with GPS or local coordinates, and then monitored on a specific time interval. Once the samples have been collected, they are usually classified on type, size and species (if possible) and recorded on a spreadsheet.[19] When measuring bulk litterfall for an area, ecologists will weigh the dry contents of the litterbag. By this method litterfall flux can be defined as:
litterfall (kg m−2 yr−1) = total litter mass (kg) / litterbag area (m2)[20]
The litterbag may also be used to study decomposition of the litter layer. By confining fresh litter in the mesh bags and placing them on the ground, an ecologist can monitor and collect the decay measurements of that litter.[6] An exponential decay pattern has been produced by this type of experiment: $\frac{X}{X_o} = e^{-k}$, where $X_o$ is the initial leaf litter and $k$ is a constant fraction of detrital mass.[2]
The mass-balance approach is also utilized in these experiments and suggests that the decomposition for a given amount of time should equal the input of litterfall for that same amount of time.
litterfall = k(detrital mass)[2]
## Issues
### Change due to invasive earthworms
In some regions of Australia and North America, earthworms have been introduced where they are not native. Non-native earthworms have led to environmental changes by accelerating the rate of decomposition of litter. These changes are being studied, but may have negative impacts on some inhabitants such as salamanders.[21]
## References
1. ^ W. M. Lonsdale (1988). "Predicting the amount of litterfall in forests of the world". Annals of Botany 61 (3): 319–324.
2. Schlesinger, William H. Biogeochemistry: An Analysis of Global Change. 2nd Edition. Academic Press. 108, 135, 152–158, 180–183, 191–194. (1997).
3. ^ "Soil Classification". Faculty of Land and Food Systems. The University of British Columbia. Retrieved March 20, 2012.
4. ^ A. V. Spain (1984). "Litterfall and the standing crop of litter in three tropical Australian rainforests". Journal of Ecology 72: 947–961. JSTOR 2259543.
5. ^ "Litter Fall in the North American Baldcypress Swamp Network, Illinois to Louisiana, 2003". Nwrc.usgs.gov. 2013-08-19. Retrieved 2014-04-09.
6. ^ a b c d Packham, J.R.; Harding, D.J.L.; Hilton, G.M.; Stuttard, R.A. (1992). Functional Ecology of Woodlands and Forests. London: Chapman & Hall. pp. 133–134, 246–247, 265. ISBN 0412439506.
7. ^ Chanasyk, D.S.; Whitson, I.R.; Mapfumo, E.; Burke, J.M.; Prepas, E.E. (2003). "The Impacts of Forest Harvest and Wildfire on Soils and Hydrology in Temperate Forests: A Baseline to Develop Hypotheses for the Boreal Plain". Journal of Environmental Engineering Science 2: S51–S62. doi:10.1139/S03-034.
8. ^ Ice, George G.; Neary, D.G.; Adams, P.W. (2004). "Effects of Wildfire on Soils and Watershed Processes". Journal of Forestry 102 (6): 16–20(5). Retrieved March 20, 2012.
9. ^ Bot, Alexandra (2005). The Importance of Soil Organic Matter. Rome: Food and Agriculture Organizations of the United Nations. pp. Chapter 3. ISBN 92-5-105366-9.
10. ^ Writer David Attenborough, Director Scott Alexander, Producer Hilary Jeffkins (2008-02-11). "Land Invaders". Life in Cold Blood. BBC. BBC One.
11. ^ Dunn, Jon; Garrett, Kimball (1997). Warblers. New York: Peterson Field Guides. p. 451. ISBN 0-395-78321-6.
12. ^ Richard L. Ward & C. Les Marcum (2005). "Lichen litterfall consumption by wintering deer and elk in western Montana". Journal of Wildlife Management 69 (3): 1081–1089. doi:10.2193/0022-541X(2005)069[1081:LLCBWD]2.0.CO;2. JSTOR 3803347.
13. ^ Breymeyer, A.I., B. Berg, S.T. Gower, & D. Johnson. “Temperate Coniferous Forests” Scientific Committee on Problems of the Environment (SCOPE). Vol. 56: Global Change: Effects on Coniferous Forests and Grasslands Carbon Budget, Ch. 3. (1996).
14. ^ J. Chave, D. Navarrete, S. Almeida, E. Álvarez, L. E. O. C. Aragão, D. Bonal, P. Châtelet, J. E. Silva-Espejo, J.-Y. Goret, P. von Hildebrand, E. Jiménez, S. Patiño, M. C. Peñuela, O. L. Phillips, P. Stevenson & Y. Malhi (2009). "Regional and seasonal patterns of litterfall in tropical South America" (PDF). Biogeosciences 7 (1): 43–55. doi:10.5194/bg-7-43-2010.
15. ^ Scott D. Bridgham, John Pastor, Charles A. McClaugherty, & Curtis J. Richardson (1995). "Nutrient-use efficiency: a litterfall index, a model, and a test along a nutrient-availability gradient in North Carolina peatlands" (PDF). The American Naturalist 145 (1): 1–21. doi:10.1086/285725.
16. ^ Melillo, J.M., & J.R. Gosz. “Interactions of Biogeochemical Cycles in Forest Ecosystems” Scientific Committee on Problems of the Environment (SCOPE). Vol. 21: The Major Biogeochemical Cycles and Their Interactions, Ch. 6. (1983).
17. ^ Simmons, Jeffrey A. “Measuring Litterfall Flux.” West Virginia Wesleyan College (2003).
18. ^ "Spatial variations of nitrogen deposition and its effect on forest biochemical processes". Forest Research. Retrieved March 27, 2011.
19. ^ Estrella, Stephanie. “Standard Operating Procedures for Litterfall Collection, Processing, and Analysis: Version 2.0.” Washington State Department of Ecology. (2008).
20. ^ Bastrup-Birk, A., & Nathalie Bréda. “Report on Sampling and Analysis of Litterfall” United Nations Economic Commission for Europe Convention on Long-Range Transboundary Air Pollution: International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests. (2004).
21. ^ Maerz, John C.; Nuzzo, Victoria A.; Blossey, Bernd (2009). "Declines in Woodland Salamander Abundance Associated with Non-Native Earthworm and Plant Invasions". Conservation Biology 23 (4). Retrieved 28 April 2012. | {"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": 3, "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": 0.5482696890830994, "perplexity": 11886.177030961939}, "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-2014-41/segments/1410657129409.8/warc/CC-MAIN-20140914011209-00090-ip-10-196-40-205.us-west-1.compute.internal.warc.gz"} |
http://clay6.com/qa/48027/find-the-middle-term-in-the-expansion-of-big-large-frac-9y-big- | Browse Questions
# Find the middle term in the expansion of $\big(\large\frac{3}{3}$$+9y\big)^{10} \begin{array}{1 1}(A)\;61236\\(B)\;6236x^2y^4\\(C)\;61236x^5y^5\\(D)\;61236x^4y^3\end{array} Can you answer this question? ## 1 Answer 0 votes Toolbox: • If n+1 is odd,the middle term is \large\frac{(n+1)+1}{2}$$+n=\large\frac{n+2}{2}$$+h Number of terms in the expansion is 10+1=11 Middle term of the expansion is \large\frac{11+1}{2}$$=T_6$
$T_{r+1}=C(10,r)(\large\frac{x}{3})^{10-r}$$(9y)^r But T_{n+r}=T_6 or r+1=6 Putting r=5 in (1) we have T_6=T_{5+1}=C(10,5)(\large\frac{x}{3})^{10-5}$$(9y)^5$
$\Rightarrow C(10,5)\large\frac{x^5}{3^5}$$.9^5y^5 \Rightarrow C(10,5) 3^5 X^5y^5 \Rightarrow \large\frac{10!}{5!(10-5)!}$$3^5x^5y^5$
$\Rightarrow \large\frac{10!}{5!5!}$$3^5x^5y^5 \Rightarrow \large\frac{10\times 9\times 8\times 7\times 6\times 5!}{5\times 4\times 3\times 2\times 1\times 5!}$$3^5x^5y^5$
$\Rightarrow 61236 x^5y^5$
Hence (C) is the correct answer. | {"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": 0.9972704648971558, "perplexity": 4263.398264108971}, "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-2016-44/segments/1476988719397.0/warc/CC-MAIN-20161020183839-00384-ip-10-171-6-4.ec2.internal.warc.gz"} |
http://mathhelpforum.com/calculus/120918-need-help-easy-limit-print.html | # need help with an easy limit
• Dec 17th 2009, 02:14 AM
newby
need help with an easy limit
lim x->1 (x^3 - 3x +2)/(x^4 - 4x + 3) = ?
I tried with L'Hospital's rule but it seems it doesn't work (it still gives me 0/0... Maybe I didn't apply it well?). Any suggestions?
[Sorry if it's a dumb question, but I am not very good at math...(Lipssealed)]
• Dec 17th 2009, 02:37 AM
Raoh
Quote:
Originally Posted by newby
lim x->1 (x^3 - 3x +2)/(x^4 - 4x + 3) = ?
I tried with L'Hospital's rule but it seems it doesn't work (it still gives me 0/0... Maybe I didn't apply it well?). Any suggestions?
[Sorry if it's a dumb question, but I am not very good at math...(Lipssealed)]
$\lim_{x\to 1}\frac{x^3-3x +2}{x^4-4x + 3}$= $\lim_{x \rightarrow 1 } \frac{ 3x^2-3}{4x^3-4 }$= $\lim_{ x \rightarrow 1} \frac{3 }{4 } \left ( \frac{ x^2-1}{x^3-1 } \right )$ = $\lim_{ x \rightarrow 1} \frac{ 3}{ 4} \left ( \frac{ x+1}{x^2+x+1 } \right )$= $\frac{ 3}{4 } \left ( \frac{2 }{3 } \right ) = \frac{ 1}{ 2}$
hope i'm right(Itwasntme)
• Dec 17th 2009, 02:40 AM
newby
Quote:
Originally Posted by Raoh
$\lim_{x\to 1}\frac{x^3-3x +2}{x^4-4x + 3}$= $\lim_{x \rightarrow 1 } \frac{ 3x^2-3}{4x^3-4 }$= $\lim_{ x \rightarrow 1} \frac{3 }{4 } \left ( \frac{ x^2-1}{x^3-1 } \right )$ = $\lim_{ x \rightarrow 1} \frac{ 3}{ 4} \left ( \frac{ x+1}{x^2+x+1 } \right )$= $\frac{ 3}{4 } \left ( \frac{2 }{3 } \right ) = \frac{ 1}{ 2}$
hope i'm right(Itwasntme)
Thanks a lot! I feel more clever now (Rofl) !
Thanks again :)!
• Dec 17th 2009, 03:05 AM
earboth
Quote:
Originally Posted by newby
lim x->1 (x^3 - 3x +2)/(x^4 - 4x + 3) = ?
I tried with L'Hospital's rule but it seems it doesn't work (it still gives me 0/0... Maybe I didn't apply it well?). Any suggestions?
[Sorry if it's a dumb question, but I am not very good at math...(Lipssealed)]
Here comes a slightly different way:
As long as the quotient is $\frac00$ you can apply de l'Hopital's rule:
$\lim_{x\to 1}\frac{x^3-3x +2}{x^4-4x + 3} = \lim_{x\to 1}\frac{3x^2-3}{4x^3-4} = \lim_{x\to 1}\frac{6x}{12x^2} = \frac6{12} = \frac12$
• Dec 17th 2009, 03:26 AM
newby
Quote:
Originally Posted by earboth
Here comes a slightly different way:
As long as the quotient is $\frac00$ you can apply de l'Hopital's rule:
$\lim_{x\to 1}\frac{x^3-3x +2}{x^4-4x + 3} = \lim_{x\to 1}\frac{3x^2-3}{4x^3-4} = \lim_{x\to 1}\frac{6x}{12x^2} = \frac6{12} = \frac12$
Thank you too! I didn't know I could use the rule many times! :)
• Dec 17th 2009, 03:40 AM
Raoh
Quote:
Originally Posted by newby
Thank you too! I didn't know I could use the rule many times! :)
neither i (Rofl). | {"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": 14, "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": 0.9338624477386475, "perplexity": 1682.9583266139036}, "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-2017-39/segments/1505818687820.59/warc/CC-MAIN-20170921134614-20170921154614-00472.warc.gz"} |
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I wanted to end with Free Power laugh. I will say, I like Free Electricity Free Power for his comedy. Sure sometimes I am not sure if it comes across to most people as making fun of spirituality and personal work, or if it just calls out the ridiculousness of some of it when we do it inauthentically, but he still has some great jokes. Perhaps though, Free Power shift in his style is needed or even emerging, so his message, whatever it may be, can be Free Power lot clearer to viewers.
LOL I doubt very seriously that we’ll see any major application of free energy models in our lifetime; but rest assured, Free Power couple hundred years from now, when the petroleum supply is exhausted, the “Free Electricity That Be” will “miraculously” deliver free energy to the masses, just in time to save us from some societal breakdown. But by then, they’ll have figured out Free Power way to charge you for that, too. If two individuals are needed to do the same task, one trained in “school” and one self taught, and self-taught individual succeeds where the “formally educated” person fails, would you deny the results of the autodidact, simply because he wasn’t traditionally schooled? I’Free Power hope not. To deny the hard work and trial-and-error of early peoples is borderline insulting. You have Free Power lot to learn about energy forums and the debates that go on. It is not about research, well not about proper research. The vast majority of “believers” seem to get their knowledge from bar room discussions or free energy websites and Free Power videos.
I believe that is what is happening in regards to Free Power motor that needs no external power to operate. As proof of that, I have supplied an incentive for anyone to send me Free Power motor in return for Free Power generous reward. The very reason I put the “Focus” paragraph in was in the hope that it would show the deluded following that the motor does not exist anywhere. Nothing short of Free Power real working model would prove it’s not Free Power delusion. Stay focused on that and you will see the truth of what I am saying. Harvey1A magical magnetic motor? Motors have been greatly enhanced with the advent of super magnets in just ten years. Smaller and more powerful to say the least. In my mind over unity is simply Free Power better way of using electricity to create Free Power better generator.
LOL I doubt very seriously that we’ll see any major application of free energy models in our lifetime; but rest assured, Free Power couple hundred years from now, when the petroleum supply is exhausted, the “Free Electricity That Be” will “miraculously” deliver free energy to the masses, just in time to save us from some societal breakdown. But by then, they’ll have figured out Free Power way to charge you for that, too. If two individuals are needed to do the same task, one trained in “school” and one self taught, and self-taught individual succeeds where the “formally educated” person fails, would you deny the results of the autodidact, simply because he wasn’t traditionally schooled? I’Free Power hope not. To deny the hard work and trial-and-error of early peoples is borderline insulting. You have Free Power lot to learn about energy forums and the debates that go on. It is not about research, well not about proper research. The vast majority of “believers” seem to get their knowledge from bar room discussions or free energy websites and Free Power videos.
I might be scrapping my motor and going back to the drawing board. Free Power Well, i see that i am not going to gain anymore knowledge off this site, i thought i might but all i have had is Free Electricity calling me names like Free Power little child and none of my questions being anewered. Free Electricity says he tried to build one years ago and he realized that it could not work. Ok tell me why. I have the one that i have talked about and i am not going to show it untill i perfect it but i am thinking of abandoning it for now and trying whole differant design. Can the expert Free Electricity answer shis? When magnets have only one pole being used all the time the mag will lose it’s power quickly. What will happen if you use both poles in the repel state? Free Electricity that ballance the mag out or drain it twice as fast? How long will Free Power mag last running in the repel state all the time? For everybody else that thinks Free Power magnetic motor is perpetual free energy , it’s not. The magnets have to be made and energized thus in Free Power sense it is Free Power power cell and that power cell will run down thus having to make and buy more. Not free energy. This is still fun to play with though.
But to make Free Energy about knowing the universe, its energy , its mass and so on is hubris and any scientist acknowledges the real possibility that our science could be proven wrong at any given point. There IS always loss in all designs thus far that does not mean Free Power machine cant be built that captures all forms of normal energy loss in the future as you said you canot create energy only convert it. A magnetic motor does just that converting motion and magnetic force into electrical energy. Ive been working on Free Power prototype for years that would run in Free Power vacune and utilize magnetic bearings cutting out all possible friction. Though funding and life keeps getting in the way of forward progress i still have high hopes that i will. Create Free Power working prototype that doesnt rip itself apart. You are really an Free Power*. I went through Free Electricity. Free Power years of pre-Vet. I went to one of the top HS. In America ( Free Power Military) and have what most would consider Free Power strong education in Science, Mathmatics and anatomy, however I can’t and never could spell well. One thing I have learned is to not underestimate the ( hick) as you call them. You know the type. They speak slow with Free Power drawl. Wear jeans with tears in them. Maybe Free Power piece of hay sticking out of their mouths. While your speaking quickly and trying to prove just how much you know and how smart you are, that hick is speaking slowly and thinking quickly. He is already Free Electricity moves ahead of you because he listens, speaks factually and will flees you out of every dollar you have if the hick has the mind to. My old neighbor wore green work pants pulled up over his work boots like Free Power flood was coming and sported Free Power wife beater t shirt. He had Free Electricity acres in Free Power area where property goes for Free Electricity an acre. Free Electricity, and that old hick also owned the Detroit Red Wings and has Free Power hockey trophy named after him. Ye’re all retards.
Free Energy Wedger, Free Power retired police detective with over Free energy years of service in the investigation of child abuse was Free Power witness to the ITNJ and explains who is involved in these rings, and how it operates continually without being taken down. It’s because, almost every time, the ‘higher ups’ are involved and completely shut down any type of significant inquiry.
Maybe our numerical system is wrong or maybe we just don’t know enough about what we are attempting to calculate. Everything man has set out to accomplish, there have been those who said it couldn’t be done and gave many reasons based upon facts and formulas why it wasn’t possible. Needless to say, none of the ‘nay sayers’ accomplished any of them. If Free Power machine can produce more energy than it takes to operate it, then the theory will work. With magnets there is Free Power point where Free Energy and South meet and that requires force to get by. Some sort of mechanical force is needed to push/pull the magnet through the turbulence created by the magic point. Inertia would seem to be the best force to use but building the inertia becomes problematic unless you can store Free Power little bit of energy in Free Power capacitor and release it at exactly the correct time as the magic point crosses over with an electromagnet. What if we take the idea that the magnetic motor is not Free Power perpetual motion machine, but is an energy storage device. Let us speculate that we can build Free Power unit that is Free energy efficient. Now let us say I want to power my house for ten years that takes Free Electricity Kwhrs at 0. Free Energy /Kwhr. So it takes Free energy Kwhrs to make this machine. If we do this in Free Power place that produces electricity at 0. 03 per Kwhr, we save money.
NOTHING IS IMPOSSIBLE! Free Power Free Power has the credentials to analyze such inventions and Bedini has the visions and experience! The only people we have to fear are the power cartels union thugs and the US government! rychu Free Energy two books! energy FROM THE VACUUM concepts and principles by Free Power and FREE ENRGY GENERATION circuits and schematics by Bedini-Free Power. Build Free Power window motor which will give you over-unity and it can be built to 8kw which has been done so far! NOTHING IS IMPOSSIBLE! Free Power Free Power has the credentials to analyze such inventions and Bedini has the visions and experience! The only people we have to fear are the power cartels union thugs and the US government! Free Energy two books! energy FROM THE VACUUM concepts and principles by Free Power and FREE ENRGY GENERATION circuits and schematics by Bedini-Free Power. Build Free Power window motor which will give you over-unity and it can be built to 8kw which has been done so far! NOTHING IS IMPOSSIBLE! Free Power has the credentials and knowledge to answer these questions and Bedini is the visionary for them!
No, it’s not alchemy or magic to understand the attractive/resistive force created by magnets which requires no expensive fuel to operate. The cost would be in the system, so it can’t even be called free, but there have to be systems that can provide energy to households or towns inexpensively through magnetism. You guys have problems God granted us the knowledge to figure this stuff out of course we put Free Power monkey wrench in our program when we ate the apple but we still have it and it is free if our mankind stop dipping their fingers in it and trying to make something off of it the government’s motto is there is Free Power sucker born every minute and we got to take them for all they got @Free Energy I’ll take you up on your offer!!! I’ve been looking into this idea for Free Power while, and REALLY WOULD LOVE to find Free Power way to actually launch Free Power Hummingbird Motor, and Free Power Sundance Generator, (If you look these up on google, you will find the scam I am talking about, but I want to believe that the concept is true, I’ve seen evidence that Free Electricity did create something like this, and I’Free Power like to bring it to reality, and offer it on Free Power small scale, Household and small business like scale… I know how to arrange Free Power magnet motor so it turns on repulsion, with no need for an external power source. My biggest obstacle is I do not possess the building skills necessary to build it. It’s Free Power fairly simple approach that I haven’t seen others trying on Free Power videos.
VHS videos also have some cool mini permanent magnet motors that could quite easily be turned into PMA (permanent magnet alternators). I pulled one apart about Free Power month ago. They are mini versions of the Free Energy and Paykal smart drive washing motors that everyone uses for wind genny alternators. I have used the smart drive motors on hydro electric set ups but not wind. You can wire them to produce AC or DC. Really handy conversion. You can acess the info on how to do it on “the back shed” (google it). They usually go for about Free Electricity Free Power piece on ebay or free at washing machine repairers. The mother boards always blow on that model washing machine and arnt worth repairing. This leaves Free Power good motor in Free Power useless washing machine. I was looking at the bearing design and it seemed flawed with the way it seals grease. Ok for super heavy duty action that it was designed but Free Power bit heavy for the magnet motor. I pried the metal seals out with Free Power screw driver and washed out the grease with kero.
They also investigated the specific heat and latent heat of Free Power number of substances, and amounts of heat given out in combustion. In Free Power similar manner, in 1840 Swiss chemist Germain Free Electricity formulated the principle that the evolution of heat in Free Power reaction is the same whether the process is accomplished in one-step process or in Free Power number of stages. This is known as Free Electricity’ law. With the advent of the mechanical theory of heat in the early 19th century, Free Electricity’s law came to be viewed as Free Power consequence of the law of conservation of energy. Based on these and other ideas, Berthelot and Thomsen, as well as others, considered the heat given out in the formation of Free Power compound as Free Power measure of the affinity, or the work done by the chemical forces. This view, however, was not entirely correct. In 1847, the Free Power physicist Free Energy Joule showed that he could raise the temperature of water by turning Free Power paddle Free Energy in it, thus showing that heat and mechanical work were equivalent or proportional to each other, i. e. , approximately, dW ∝ dQ. | {"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": 0.4031370282173157, "perplexity": 1610.5364977197435}, "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/1618039610090.97/warc/CC-MAIN-20210422130245-20210422160245-00591.warc.gz"} |
http://mathhelpforum.com/algebra/58433-could-you-please-show-me-how-solve.html | 1. ## Could you please show me how to solve this...
Pizza Corner sells medium and large specialty pizzas. A medium Meat Lovers pizza costs $10.95, and a large Meat Lovers pizza costs$14.95. One Saturday a total of 50 Meat Lovers pizzas were sold, and the receipts from the Meat Lovers pizzas were $663.50. How many medium and how many large Meat Lovers pizzas were sold? 2. Hi Originally Posted by camstill Pizza Corner sells medium and large specialty pizzas. A medium Meat Lovers pizza costs$10.95, and a large Meat Lovers pizza costs $14.95. One Saturday a total of 50 Meat Lovers pizzas were sold, and the receipts from the Meat Lovers pizzas were$663.50. How many medium and how many large Meat Lovers pizzas were sold?
Well,
define x = amount of medium Meat Lovers pizza
define y = amount of large Meat Lovers pizza
x*10.95 + y*14.95
50 pizzas were sold, that means x+y = 50 (1)
Furthermore someone got 663.50$that means x*10.95 + y*14.95 = 663.50$ (2)
you have 2 equations, solve them
=> x = 21, y = 29
Alright?
3. I understand the system of equations but am having trouble solving them. Could you show your work? Thanks.
4. Originally Posted by camstill
I understand the system of equations but am having trouble solving them. Could you show your work? Thanks.
x+y = 50 (1) => x = 50 -y
x*10.95 + y*14.95 = 663.50\$ (2)
You know x => (50 -y)*10.95+y*14.95 =663.50
547.5-y*10.95+y*14.95 =663.50
-y*10.95+y*14.95 =663.50-547.5
4y = 116
y = 116/4
y = 29
and you know x = 50 -y, thats why x = 50 - 29 = 21 | {"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": 0.45435023307800293, "perplexity": 4550.631717675395}, "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-2018-09/segments/1518891816094.78/warc/CC-MAIN-20180225031153-20180225051153-00365.warc.gz"} |
https://it.mathworks.com/help/matlab/ref/psi.html | # psi
Digamma and polygamma functions
## Syntax
Y = psi(X)
Y = psi(k,X)
## Description
example
Y = psi(X) evaluates the digamma function for each element of array X, which must be real and nonnegative.
example
Y = psi(k,X) evaluates the polygamma function of X, which is the kth derivative of the digamma function at X. Thus, psi(0,X) is the digamma function, psi(1,X) is the trigamma function, psi(2,X) is the tetragamma function, and so on.
## Examples
collapse all
Use the psi function to evaluate the Euler-Mascheroni constant $\gamma$, also known as Euler's constant.
format long Y = -psi(1)
Y = 0.577215664901532
Evaluate the trigamma function of 2.
format long Y1 = psi(1,2)
Y1 = 0.644934066848226
Check that the result is equal to ${\pi }^{2}/6-1$.
Y2 = pi^2/6 - 1
Y2 = 0.644934066848226
isequal(Y1,Y2)
ans = logical 1
Define the domain.
X = 0:0.05:5;
Calculate the digamma and the next three polygamma functions.
Y = zeros(4,101); for i = 0:3 Y(i+1,:) = psi(i,X); end
Plot the digamma and the next three polygamma functions.
plot(X,Y) axis([0 5 -10 10]) legend('\psi','\psi_1','\psi_2','\psi_3','Location','Best') title('Digamma and The Next Three Polygamma Functions','interpreter','latex') xlabel('$x$','interpreter','latex') ylabel('$\psi_k(x)$','interpreter','latex')
## Input Arguments
collapse all
Input, specified as a scalar, vector, matrix, or multidimensional array of nonnegative real numbers. X cannot be sparse.
Data Types: single | double
Order of derivative, specified as a nonnegative integer scalar. k must be smaller than 231-1.
Data Types: single | double
collapse all
### Digamma Function
The digamma function is the first derivative of the logarithm of the gamma function:
$\psi \left(x\right)=\frac{d}{dx}\mathrm{ln}\Gamma \left(x\right)=\frac{{\Gamma }^{\prime }\left(x\right)}{\Gamma \left(x\right)}.$
### Polygamma Function
The polygamma function of the order k is the (k + 1)th derivative of the logarithm of the gamma function:
${\psi }^{\left(k\right)}\left(x\right)=\frac{{d}^{k+1}}{d{x}^{k+1}}\mathrm{ln}\Gamma \left(x\right)=\frac{{d}^{k}}{d{x}^{k}}\psi \left(x\right).$
## References
[1] Abramowitz, M. and I. A. Stegun, Handbook of Mathematical Functions, Dover Publications, 1965, Sections 6.3 and 6.4. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 4, "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": 0.9222075939178467, "perplexity": 3169.6848446901176}, "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/1631780056890.28/warc/CC-MAIN-20210919125659-20210919155659-00392.warc.gz"} |
https://www.physicsforums.com/threads/physics-today-rely-on-an-observer.3938/ | # Physics today rely on an observer
• Start date
• #1
sophia
Considering that certain areas in physics today rely on an observer, such as when considering the collaspse of a wavefunction, I think that we need a good physical definition of an observation.
So what is an observation? I like to think of it as a change in configuration or state. Think about it. When we make observations we look around us and adapt to the situation at hand. We change. And chimps, cats, or viruses are just as good at being obsrevers as we are. But what of inanimate objects? Surely a particle behaves in the same way, abeit not conciously. it changes to it's environment, for instance if hit by a photon it goes to a higher energy level. so particles and everything else is an observer.
I like this explanation, it makes things simpler. Consider Schroedinger paradox. the paticle dector observe the atoms decay and the wave function collaspes for it. the cat observes the poison gas and knows it dies, it doesn't need a human to tell it so. But we have not ob served it so the wavefunction does not colaspse for us.
I was just wondering what you thuoght of this.
Related Other Physics Topics News on Phys.org
• #2
920
0
The wavefunction of a system collapses when the system is measured, not when the system observes its surroundings. The difficult thing is to define what is a measure. There are several scientists, Wigner one of the most known, that says that is necessary conscience to perform a measure, but this is a very much anthropocentric idea, and the majority of the investigators agree that a measure don't need to involve humans
• #3
jcsd
Gold Member
2,090
11
There is no mathematical or well-defined description of a quantum measurement which is probably the largest flaw of the conventional theory of quantum measurement, the Copenhagen intpretation.
On top of this you have the Quantum Mechanical measurement problem which begs the question, should the detector be considered part of the system or should it be treated classically? Of course if you do treat the detector as part of the system then you'll need another detector to detect that system, which could again be argued to be part of the system ad infinitum.
• #4
auxin9
might an object in the area of plants, and what thy do with light, fit the bill as a good definition of an observation without wave function.
• #5
Staff Emeritus
Gold Member
Dearly Missed
6,786
7
Originally posted by jcsd
There is no mathematical or well-defined description of a quantum measurement which is probably the largest flaw of the conventional theory of quantum measurement, the Copenhagen intpretation.
That ain't a bug, that's a feature!
Bohr stated that quantum mechanics isn't a theory about the micro world, it's a description of our observation of the micro world. You use it to design and interpret macroscopic experiments, and to do that you don't need a theory of collapse.
To use QM to interpet the universe, in Bohr-thinking, is like using a ladder to pound a nail.
• #6
Ivan Seeking
Staff Emeritus
Gold Member
7,213
176
Measurement in Quantum Theory
"From the inception of Quantum Mechanics (QM) the concept of measurement has proved a source of difficulty. The Einstein-Bohr debates, out of which both the Einstein Podolski Rosen paradox and Schrödinger's cat paradox developed, centered upon this difficulty. The problem of measurement in quantum mechanics arises out of the fact that several principles of the theory appear to be in conflict. In particular, the dynamic principles of quantum mechanics seem to be in conflict with the postulate of collapse."
http://plato.stanford.edu/entries/qt-measurement/
• #7
jcsd
Gold Member
2,090
11
That ain't a bug, that's a feature!
Bohr stated that quantum mechanics isn't a theory about the micro world, it's a description of our observation of the micro world. You use it to design and interpret macroscopic experiments, and to do that you don't need a theory of collapse.
To use QM to interpet the universe, in Bohr-thinking, is like using a ladder to pound a nail.
No, it is widely recognised as a flaw of quantum measurement (particularly the Copenhagen intepretation) as quantum mechanics is meant to be a universal theory. If QM is only useful in describing the microscopic world it begs the question "where does the microscopic end and the macroscopic begin?".
Oddly enough a group led by Stephen Hawkings have used quantum mechanics to interpret the universe at large by constructing the 'wavefunction of the universe' which has yielded results that seem to explain the large scale structure of the universe.
• #8
Staff Emeritus
Gold Member
Dearly Missed
6,786
7
Originally posted by jcsd
No, it is widely recognised as a flaw of quantum measurement (particularly the Copenhagen intepretation) as quantum mechanics is meant to be a universal theory. If QM is only useful in describing the microscopic world it begs the question "where does the microscopic end and the macroscopic begin?".
Oddly enough a group led by Stephen Hawkings have used quantum mechanics to interpret the universe at large by constructing the 'wavefunction of the universe' which has yielded results that seem to explain the large scale structure of the universe.
Widely recognized by people who insist on reifying the wave function and, yes, interpreting QM as a universal theory. What I was decribing is caricatured as "shut up and calculate" and it is a perfectly reasonable take on the facts of QM. You don't get a "universal theory" but you don't get the insoluble collapse problem either.
As for the wave function of the universe, talk to Marcus. I believe LQG has supervened.
• #9
jcsd
Gold Member
2,090
11
The wavefunction of the universe is still a very-much ongoing project which has recently yielded results which help to explain the large scale structure of the universe.
Quantum mechanics is accepted theoritically at least as being a universal theory and if you do not accept this the quantum mechanical measurement problem becomes even accuter (as it would seemingly forbid explanations like decoherence). You cannot define exactly what is a quantum measurement or on what scale classical measurement theory takes over. The many worlds theory does seem to get around this problem, however it creates other problems that has stopped it from becoming the mainstream interpretation.
• #10
164
0
The only problem I see is trying to attach a "real" meaning to the wave function and its collapse. If you just look at it as a prediction tool, no problem. But when you try to make the wavefunction out to be an event in itself, there is going to be problems.
I think the "problem" really goes back to "superposition", trying to attach too much meaning to it, then that in turn leads to problems where you [[want/have]] to attach an independent meaning to the wavefunction, which leads to Schrodinger's Cat, etc.
It can be stopped right at superposition. In the strict Copenhagen Interpretation it does, too. They don't really talk about superposition of states, but note that you can't talk about states of something that isn't measured .. and then cop out on the definition of a measurement. And the collapse of the wave function and Schrodinger's Cat fall out as something that doesn't need to be considered.
• #11
jcsd
Gold Member
2,090
11
The quantum mechanical measurement problem is deeply tied in with the Copenhagen Interpreation and it's inabilty to satisfactorily define a quantum measurement (i.e. a measurement that collapses the wavefunction), should you not also treat the measuremnet appartus as part of the quantum system rather than treating them classically? This is basically what the QM measurement problem is about.
• #12
164
0
I have to disagree. I put no independent meaning on the wave function. Its use is only a predictive tool, and also, only after you have found/decided on an initial state. I think that is overlooked .. try formulating the Schrodenger's Cat problem without knowing there is a particle in the enclosure to begin with, or something about that particle .. one that will trip the lever to release the poison. The wave function will be of no use. How come? if it leads an independent existance?
I left something out in my post .. superposition is not the only thing that can lead to viewing the wave function independently .. intanglement also tends to give the wave function a life of its own. Its much harder to deny that a problem as it is superposition.
I think Bohr did it the same way as denying superposition though, that there is no such thing as a "state" until a measurement is made .. even if after the measurement was made it corresponds to predictions before the measurement.
Granted Bohr/Copenhagen wouldn't define what constituted a measurement, but I don't see as the wave function posing problems in it .. only if you suppose the wave function goes beyond predictions.
• #13
jcsd
Gold Member
2,090
11
The wavefunction (which you correctly state is viewed by the Copenhagen interpretation as a mathematical construct only with no physical analogue) isn't the problem here, it's the collapse of the wavefunction. The fact that a measurement cannot be described properly is a deep problem. Why shouldn't the appartus be treated as if it where in a supposition of states bewteen a postive and negative results rather than treated classically, why shouldn't WE be in a suppositon of states between having read a postive and negative result? These are problems which decoherence (a theory on why quantum behaviour does not seem to amplify to a macroscopic level in problems like Schroedinger's cat) tries to explain.
• #14
164
0
Originally posted by jcsd
... Why shouldn't the appartus be treated as if it where in a supposition of states bewteen a postive and negative results rather than treated classically, why shouldn't WE be in a suppositon of states between having read a postive and negative result? ...
I touched on that in my first post, that that is what I thought the problem actually was, superposition, rather than "collapse" of the wave function. If you take superposition out of the picture, there is no need for trying to give any meaning to the "collapse" (neglecting entanglement, which I also touched on). Just don't try to think of the collapse as a real thing that has to happen, think of it only as that the predictive power of the wave function ceases.
Another thing has happened here, down the line somewhere. People have given a proper name to this, "collapse of the wave function", just like we have given a name to an electron, or a photon. Well, those names themselves tend to conjure up properties that aren't necessarily there. Like an electron, it tends to conjure and make you (me) think of an electron as a little round ball. The name has done that; not any properties of the electron that we know about. Somewhere along the line "collapse of the wave function" has grown to add its own properties/connotations to it, and made it out to be something physical rather than an idea thought up in somebody's brain and the idea/equations written down on paper.
Take superposition out of the picture, then you don't have to worry about a combined quantum state of the entity being measured and the measuring device. You only have to worry about the quantum state of the measuring device. That's tough enough.
IMO, superpostion (in particle aspects) is denied by strictly adhering to the Copenhagen Interpretation. If you're looking only at the wave aspects of a system, then that's another matter.
• #15
jcsd
Gold Member
2,090
11
superpoistion, is part of QM and so is the collapse of the wavefunction. The collapse of the wavefunction cannot be described in mathematical or a purely abstract context. Superpoistion is also part of the Copenhagen interpretation and is a clear mathematical property of Hermitian matrices
The QM measurement problem is still there, what I think you're missing is that it is more of a practical than philosophical problem and it will probably take a theory of quantum gravity to solve.
• #16
164
0
Originally posted by jcsd
superpoistion, is part of QM and so is the collapse of the wavefunction. The collapse of the wavefunction cannot be described in mathematical or a purely abstract context. Superpoistion is also part of the Copenhagen interpretation and is a clear mathematical property of Hermitian matrices
The QM measurement problem is still there, what I think you're missing is that it is more of a practical than philosophical problem and it will probably take a theory of quantum gravity to solve.
Superposition is part of Copenhagen QM as it applies to wave properties, not particle properties. And part of the problem is trying to overextend the wave function to particle aspects, such as particle detection. In short, the wave function ceases to give any predictive value once a particle is detected, and IMO, the collapse of the wave function is nothing but a metaphor (or simile, or whatever that correct term is). There is no transition between wave/particle .. it's either/or. When you talk of one, the other has to be totally left behind.
• #17
jcsd
Gold Member
2,090
11
Forget the distinction between wave and particle as that can be rather arbitary as particles can display both properties at the same time in experiments like the delayed choice experiment, anyway it's not important to the QM measuremnet problem.
The problem is how can you say when a quantum system's evolution goes from being decided by the time-dependent Schroedinger equation to a collapse into one of the eigenstates? I mean you can say from the behaviour of the system but defining this collapse mathematically cannot be done.
• #18
164
0
Originally posted by jcsd
Forget the distinction between wave and particle as that can be rather arbitary as particles can display both properties at the same time in experiments like the delayed choice experiment, anyway it's not important to the QM measuremnet problem.
I don't believe that to be true, and IMO it is important. In that instance the wave and particle properties are not taken at the exact same time in the exact same measurement, and simply, you don't have to take a measurement for wave aspects to appear. When the particle measurement is taken, those wave properties disappear, even in a delayed choice experiment. These two things are totally distinct, and cannot be taken in combination, or viewed/measured at the same time.
The problem is how can you say when a quantum system's evolution goes from being decided by the time-dependent Schroedinger equation to a collapse into one of the eigenstates? I mean you can say from the behaviour of the system but defining this collapse mathematically cannot be done.
That's simply one of the "funny" things about QM, and is not limited to the Copenhagen Interpretation.
Let me say it this way, because there is general agreement, at least I believe so. When an electron jumps from one orbital to another because of emitting or obsorbing a photon, it's generally agreed there is no transition state. The electron is in one orbital 1 [[moment]], and another orbital the next [[moment]. I don't know of persons that believe in the collapse of the wave function as being a physical happening in measurements as talking about this instance in respect to a transition.
But the word "collapse", and how it is used in "collapse of the wavefunction" has connotations of a transition. If that is the case, it ought to be possible to detect both wave and particle aspect at the same time. That might be the whole basis of what you are saying, in trying to determine what constitutes a collapse of the wave function, trying to find/define a moment of transition.
IMO, that's like trying to kill a dead skunk! ;). It seems to me it is a need to try to retain some aspects of Classical physics that there is transition, when there isn't transition.
I've enjoyed the discussion!
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3K | {"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": 0.843925952911377, "perplexity": 613.7421505081137}, "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-2020-40/segments/1600400190270.10/warc/CC-MAIN-20200919044311-20200919074311-00553.warc.gz"} |
https://ko-kr.knowledgebase.renesas.com?title=English_Content/Analog%26Power/Training_%26_Design_Support/Part_Selection/Electrical_Characteristics/Optoelectronics/Can_the_voltage_of_photocoupler_be_reduced_if_connected_to_a_resistor%3F | 메인 콘텐츠로 건너뛰기
# Can the voltage of photocoupler be reduced if connected to a resistor?
Latest Updated:01/01/2009
## Question:
The maximum input voltage of a photocoupler is 5 V in my system. However, none of the input (LED) forward voltages stated in the characteristics tables are more than 2 V.
In such a case, can the voltage applied to the photocoupler be decreased by connecting a resistor to the photocoupler in series? | {"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": 0.8723154664039612, "perplexity": 2694.365432736193}, "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-2017-39/segments/1505818693866.86/warc/CC-MAIN-20170925235144-20170926015144-00557.warc.gz"} |
http://www.cfd-online.com/Forums/main/159564-buoyancy-boussinesq-approximation-temperature-dependence.html | # Buoyancy: Boussinesq approximation or temperature dependence?
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September 18, 2015, 05:16 Buoyancy: Boussinesq approximation or temperature dependence? #1 Member Agustín Villa Join Date: Apr 2013 Location: Brussels Posts: 97 Rep Power: 5 Hi folks, I am dealing with a simulation of an incompressible fluid, where I have natural convection. Most of the people use the Boussinesq approximation, where they use as the expansion coefficient. But, in the case where the density (or temperature) changes a lot, this model should not be applied, and temperature dependence of density must be taken into account. When I check the validity of the Boussinesq approximation, some people says a small density difference (ie, temperature), but never said the exact value, or a reference, or a difference that allows . Mi question is if you know any criteria to choose between one of those ways? Thanks for your answer Last edited by agustinvo; September 18, 2015 at 06:33.
September 18, 2015, 06:49
#2
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 2,257
Rep Power: 28
Quote:
Originally Posted by agustinvo Hi folks, I am dealing with a simulation of an incompressible fluid, where I have natural convection. Most of the people use the Boussinesq approximation, where they use as the expansion coefficient. But, in the case where the density (or temperature) changes a lot, this model should not be applied, and temperature dependence of density must be taken into account. When I check the validity of the Boussinesq approximation, some people says a small density difference (ie, temperature), but never said the exact value, or a reference, or a difference that allows . Mi question is if you know any criteria to choose between one of those ways? Thanks for your answer
as the approximation is based on a linear expansion, the analysis generally says no more than some degree of variation in temperature
September 18, 2015, 07:25
#3
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Agustín Villa
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Quote:
Originally Posted by FMDenaro as the approximation is based on a linear expansion, the analysis generally says no more than some degree of variation in temperature
Hi
in my case, in the range of temperatures I am working, the density varies linearly. So, in the case I use Boussinesq, it will be only valid, if there is a linear variation?
September 18, 2015, 07:32
#4
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Filippo Maria Denaro
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Quote:
Originally Posted by agustinvo Hi in my case, in the range of temperatures I am working, the density varies linearly. So, in the case I use Boussinesq, it will be only valid, if there is a linear variation?
no, it depends on the range of variation, you cannot consider Bousinnesq if you get more than some degree
September 18, 2015, 07:36
#5
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Agustín Villa
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Quote:
Originally Posted by FMDenaro no, it depends on the range of variation, you cannot consider Bousinnesq if you get more than some degree
I agree with you in that, but every journal, report... they only apply it, without justifying if under their conditions it's ok to use Boussinesq or not.
Since there are not more indications about when it should be used, the ideal situation should be consider always temperature dependence on density.
September 18, 2015, 11:47 #6 Senior Member Lucky Tran Join Date: Apr 2011 Location: Orlando, FL USA Posts: 1,271 Rep Power: 20 The Boussinesq approximation is limited to small temperature differences because it only accounts for the changes in forces caused by temperature/density. The Boussinesq model does not actually take into account density changes (it's nearly an incompressible fluid). If your density change was purely linear, the Bounssinesq approximation would predict the correct change in buoyancy forces and in that sense it is valid to always use the Boussinesq approximation. However, if there are density changes then the constant density assumption is not valid in the sense of the remaining terms in the continuity, momentum, and energy equations (the terms involving the convective derivative). In this sense, it is always incorrect to use the Boussinesq approximation and in general, any changes in density should always be taken into account. In other words, even if your density change was purely linear, the Bounssinesq aproximation is still invalid as it does not allow for density changes (only buoyancy force changes). The criteria to determine the validity of the Bounssinesq approximation is therefore, to limit the temperature range to be small enough so that the density change is not significant. I don't know of a general criteria that is not subjective but it is analogous to: for what Mach number can a flow considered incompressible flow? It depends on the criteria that you are interested in studying (M=0.1 for some, 0.3 for others). FMDenaro and konangsh like this. Last edited by LuckyTran; September 21, 2015 at 11:28.
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All times are GMT -4. The time now is 08:05. | {"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": 0.875187337398529, "perplexity": 1532.3159098956091}, "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/1464051299749.12/warc/CC-MAIN-20160524005459-00161-ip-10-185-217-139.ec2.internal.warc.gz"} |
https://atcoder.jp/contests/abc109/tasks/abc109_b | Contest Duration: - (local time) (100 minutes) Back to Home
B - Shiritori /
Time Limit: 2 sec / Memory Limit: 1024 MB
### 問題文
しりとりとは以下のルールで遊ばれるゲームです。
• はじめ、好きな単語を発言する
• 以降、次の条件を満たす単語を発言することを繰り返す
• その単語はまだ発言していない単語である
• その単語の先頭の文字は直前に発言した単語の末尾の文字と一致する
### 制約
• N2 \leq N \leq 100 を満たす整数である
• W_i は英小文字からなる長さ 1 以上 10 以下の文字列である
### 入力
N
W_1
W_2
:
W_N
### 入力例 1
4
hoge
english
hoge
enigma
### 出力例 1
No
hoge が複数回発言されているのでしりとりのルールを守っていません。
### 入力例 2
9
basic
c
cpp
php
python
ocaml
lua
assembly
### 出力例 2
Yes
### 入力例 3
8
a
aa
aaa
aaaa
aaaaa
aaaaaa
aaa
aaaaaaa
### 出力例 3
No
### 入力例 4
3
abc
arc
agc
### 出力例 4
No
Score : 200 points
### Problem Statement
Takahashi is practicing shiritori alone again today.
Shiritori is a game as follows:
• In the first turn, a player announces any one word.
• In the subsequent turns, a player announces a word that satisfies the following conditions:
• That word is not announced before.
• The first character of that word is the same as the last character of the last word announced.
In this game, he is practicing to announce as many words as possible in ten seconds.
You are given the number of words Takahashi announced, N, and the i-th word he announced, W_i, for each i. Determine if the rules of shiritori was observed, that is, every word announced by him satisfied the conditions.
### Constraints
• N is an integer satisfying 2 \leq N \leq 100.
• W_i is a string of length between 1 and 10 (inclusive) consisting of lowercase English letters.
### Input
Input is given from Standard Input in the following format:
N
W_1
W_2
:
W_N
### Output
If every word announced by Takahashi satisfied the conditions, print Yes; otherwise, print No.
### Sample Input 1
4
hoge
english
hoge
enigma
### Sample Output 1
No
As hoge is announced multiple times, the rules of shiritori was not observed.
### Sample Input 2
9
basic
c
cpp
php
python
ocaml
lua
assembly
### Sample Output 2
Yes
### Sample Input 3
8
a
aa
aaa
aaaa
aaaaa
aaaaaa
aaa
aaaaaaa
### Sample Output 3
No
### Sample Input 4
3
abc
arc
agc
### Sample Output 4
No | {"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": 0.5202798843383789, "perplexity": 13982.469210919016}, "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/1679296948965.80/warc/CC-MAIN-20230329085436-20230329115436-00640.warc.gz"} |
http://nextbigfuture.com/2012_09_09_archive.html | ## September 15, 2012
### Innovative Solution to NASA's Near Earth Asteroid Impact Threat Mitigation
This is a phase 2 NASA NIAC study.
A Hypervelocity Asteroid Intercept Vehicle (HAIV) mission architecture, which blends a hypervelocity kinetic impactor with a subsurface nuclear explosion for optimal fragmentation and dispersion of hazardous near-Earth objects (NEOs), has been developed through a 2011 NIAC Phase I study. Despite the uncertainties inherent to the nuclear disruption approach, disruption can become an effective strategy if most fragments disperse at speeds in excess of the escape velocity of an asteroid so that a very small number of fragments impacts the Earth. Thus, the proposed HAIV system will become essential for reliably mitigating the most probable impact threat: NEOs with warning times shorter than 10 years. It offers a potential breakthrough or great leap in mission capabilities for mitigating the impact threat of NEOs. The proposed Phase II study further develops the HAIV-based mission architecture and explores its potential infusion options within NASA and beyond.
### Plasma magnetoshell aerobreaking should be one thousand times better than aerobraking
This is a NASA NIAC phase 1 study to develop plasma magnetoshell aerobraking. Any breaking drag forces on the Magnetoshell will be three orders of magnitude larger than the aerodynamic forces on the spacecraft. Magnetoshell should be one thousand times better than aerobraking.
The recent Mars Curiosity rover mission required a skylift rocket landing system because the one ton rover was too big for aerobraking on Mars. Plasma magnetoshell aerobraking could enable far less mass for stopping and landing on planet and other missions.
Mission studies have shown that manned mars missions and deep space planetary orbiters require aerobraking and aerocapture which use aerodynamic drag forces to slow the spacecraft. The ability to utilize these atmospheres to slow down and capture spacecraft dramatically reduces the cost of future missions, launch mass, and enable long term studies of the outer planets and moons that would not be possible with current propulsive braking methodologies. The Plasma Magnetoshell Aerobraking, Aerocapture, and Entry System (Magnetoshell AAES) to be developed in this program holds the potential to perform the desired braking with significantly increased drag and control while dramatically reducing the mass required. Implementation of aerobraking by employing a solid deflector or aeroshell as a method for orbit insertion and circularization has been successfully demonstrated in the past, with mass savings greater than 50%. In order to reduce the effect of frictional heating and dynamic pressure on the typically fragile aeroshell the braking must be distributed over many orbital passes at a higher altitude in the less dense regions of the atmosphere.
The Plasma Magnetoshell is based on demonstrated experimental results and the successful implementation would dramatically decrease mission risk, launch cost, mass, and overall radiation exposure. The Plasma Magnetoshell is a high-Beta (the ratio of plasma to magnetic field energy density) dipole plasma configuration which would initially be populated with ambient atmospheric gases. This plasma is formed, sustained, and expanded with an electrodeless Rotating Magnetic Field (RMF), which has been shown in previous experiments to generate the required, fully ionized, high temperature magnetized plasma. RMF plasma formation induces large currents in the plasma that inflate and maintain the large-scale magnetic structure. The primary drag-inducing interaction between the magnetically confined plasma ions and the incoming neutral atmospheric particles is that of charge exchange, which has the largest cross section. After a charge exchange, the now magnetized atmospheric ion reacts its directional momentum (in the frame of the spacecraft) onto the magnet via field line bending and stretching.
### Develop Remote Sensors that are ten times better for Better Science
This is a new NASA NIAC phase 1 study to develop remote sensors that are ten times better than today.
This NASA Innovative Research Grant activity conducts engineering analysis to demonstrate the feasibility and advantages of applying a breakthrough remote sensor calibration concept to a wide range of future NASA remote sensor science missions, e.g., PACE, GEO-CAPE, CLARREO, HySpIRI, GACM and Heliophysics research.
Our concept, currently a TRL-2 mature aerospace subsystem for use with space-based, remote sensors, improves radiometric measurement accuracy in the ultraviolet, visible and near infrared (UV/VIS/NIR) bands over current technology by a factor of 10. Our International Standard (SI) calibration concept is spectrally resolved, permitting very small changes to be detected at specific wavelengths over the continuum. The proposed concept enables future scientific and climate-class remote sensors to achieve the very low measurement uncertainty needed to accurately trend the earth radiation balance and to isolate cause/effect through highly accurate, spectrally resolved measurements in the UV/VIS/NIR from space. Such a breakthrough in remote sensor measurement accuracy is needed to obtain reliable measurements from space capable of trending decade long changes in earth climate and then associating those observed changes with root cause.
### Printable Spacecraft: Flexible Electronic Platforms for NASA Missions
This is a phase 2 NASA NIAC funded study.
Nextbigfuture had coverage of the phase 1 work
The 2 megabyte presentation of the phase 1 printable spacecraft project.
Atmospheric confetti. Inchworm crawlers. Blankets of ground penetrating radar. These are some of the unique mission concepts which are enabled by a printable spacecraft.
Flexible printed electronics is a wide-ranging technology that can enhance or even enable many engineering applications. Our concept is to utilize the commercial technology of printed electronics to design and fabricate an entire end to end functional spacecraft. The novel advancement (and therefore the technical challenge) of the concept is to apply printed electronics in a multi-functional platform by implementing every subsystem that a spacecraft might need from the scientific sensor through the data downlink and have it survive and function in a space environment. These requirements push the current state of the art for functionality as well as introduce design and manufacturing compatibility challenges among the functional subsystems. Current industry growth and commercial investment is expected to advance the functionality of available basic building blocks and components synergistically with NASA’s needs.
### Radiation Protection and Architecture Utilizing High Temperature Superconducting Magnets
This is another phase 2 NASA NIAC study. Nextbigfuture covered the phase 1 part of this project
The presentation at the spring symposium of the phase 1 work is here (5.5 megabyte pdf
Active radiation shielding concepts have been studied for many decades as a means to protect crew from deep space radiation environments. These studies yield architectures that are significantly massive and too costly to launch and assemble in space largely due to the magnet size and field strength required to deflect galactic cosmic radiation (GCR) spectra and solar particle events (SPE) for meaningful crew protection in space. Since then state-of-the-art superconducting technology has made great strides in performance including higher temperature superconductivity (HTS) and greater current carrying capacity allowing for simpler magnet cooling systems and greater magnetic field strength per unit mass.
During phase 1 of this study, extensive Monte-Carlo analysis calculations to determine radiation-shielding efficiency for extended deep space missions such as Lagrangian points, Near Earth Asteroids, and Mars have shown that a combined system of active and passive radiation shielding constitutes the most promising solution to this issue. Large, ultra-light, expandable HTS coils are feasible and are capable of reducing radiation exposure of humans in the spacecraft habitat to acceptable levels over longer duration missions.
Ultra-light HTS coils offer significant deflection power for charged particles and due to the low amount of material from the HTS magnets, secondary particle production is kept at a low level.
### Supersonic BI-directional silent wing
This is another NASA NIAC phase 1 funded study.
A supersonic bi-directional (SBiDir) flying wing (FW) has the potential to revolutionize supersonic flight with virtually zero sonic boom and ultra-high aerodynamic efficiency. The SBiDir-FW planform is symmetric about both the longitudinal and span axes. For supersonic flight, the planform can have as low aspect ratio and as high sweep angle as desired to minimize wave drag and sonic boom. For subsonic mode, the airplane will rotate 90deg in flight to achieve superior stable aerodynamic performance. The conflict of subsonic and supersonic aerodynamic performance of conventional fuselage-wing configuration is hence removed. The preliminary CFD simulation for a SBiDir-FW business jet (BJ) at Mach numbers of 1.6 and 2.0 indicates that the configuration generates no N-wave sonic boom on the ground at a high lift to pressure drag ratio L/Dp of 16. The superior supersonic aerodynamic performance is benefited from the sharp nose and ultra-slender body with a low aspect ratio of 0.33, which translates to a very high subsonic aspect ratio of 33 for high subsonic performance.
This proposal has three objectives:
1) design refinement of a supersonic SBiDir-FW BJ configuration using CFD;
2) mission analysis assisted with CFD simulation for the supersonic SBiDir-FW BJ to study the feasibility; and
3) wind tunnel testing of the SbiDir-FW BJ to verify its supersonic aerodynamic performance and sonic boom signature. The research team is highly qualified to perform the proposed tasks.
### Iraq sees oil exports reaching 6 million barrels per day by 2017
Iraq laid out more milestones on its path back to oil producing power, targeting 6 million barrels per day exports by 2017, and confirming it was currently pumping more than neighbor and fellow OPEC member Iran.
Iraq milestone targets for oil exports
Year Exports Total Production
2012 2.6 million bpd 3.2 million bpd
2013 2.9 million bpd
2014 3.5 million bpd
2015 3.75 million bpd
2016 4.5 million bpd (NBF interpolation)
2017 6.0 million bpd
Iraq with the help of foreign firms has ambitious plans to boost production capacity beyond 12 million bpd by 2017, but this target has proved unrealistic due to infrastructure bottlenecks and logistical shortcomings. It is expected to target 8-8.5 million bpd, but some oil analysts and executives see even 6 million bpd by 2017 as a stretch for the war-damaged country.
### Wired UK covers Rossi, Celani, Brillouin and Defkalion in a generally positive review
Wired UK has an article that summarizes recent developments with cold fusion / low energy nuclear reactions. They cover recent news from Rossi, Brillouin, Celani, Defkalion and others.
The weekend of 7 and 8 September saw a conference in Zurich on Rossi's reactor, known as the E-Cat. The conference mainly preached to the converted, attended by licensees who market E-Cat technology in different regions, like E-Cat Australia and Hydrofusion in the UK. Rossi has refused to give public demonstrations or prove the technology to sceptics; he wants to let the market decide. However, at the conference he produced a brief paper with details of third-party tests of an E-Cat.
The device tested was a new high-temperature model known as a Hot Cat. Previous E-Cats have been confined to around 200C -- useful for heating water but extremely inefficient for conversion to electricity. Since May 2011 Rossi has been talking about an improved version, and the new Hot Cat operates at a high enough temperature for electricity generation.
Although other scientists in the report have no known affiliations, one section was authored by David Bianchini, a radiation measurement specialist of the University of Bologna. The test, which ran for over six hours, measured an average temperature of 1,100-1,200C, and concluded that the energy output of the four-kilo Hot Cat was three 3.6 Kilowatts from an input of 1.28 Kw. Rossi says that a full scientific report will be available soon.
However, on 9 September Hydrofusion Ltd put out a press release about a demonstration of the Hot Cat in Bologna stating "early indications are that the results of the 16 July/ 7 August reports could not be reproduced." Swedish science magazine NyTeknik reported that the test was overseen by Swedish National Testing and Research Institute who did not find the Hot Cat was outputting more energy than was input. As a result, a planned investment of 65 million Kronor (£6.1 million) was withdrawn. The investors are now considering whether this affects all E-Cats or just the new Hot Cat.
Rossi has responded by saying that Hot Cat validation will not be completed for another two or three months.
## September 14, 2012
### Transparent Memristors
The transparent electronics that were pioneered at Oregon State University may find one of their newest applications as a next-generation replacement for some uses of non-volatile flash memory, a multi-billion dollar technology nearing its limit of small size and information storage capacity.
Researchers at OSU have confirmed that zinc tin oxide, an inexpensive and environmentally benign compound, has significant potential for use in this field, and could provide a new, transparent technology where computer memory is based on resistance, instead of an electron charge.
Solid State Electronics - Resistive switching in zinc–tin-oxide
Abstract
Bipolar resistive switching is demonstrated in the amorphous oxide semiconductor zinc–tin-oxide (ZTO). A gradual forming process produces improved switching uniformity. Al/ZTO/Pt crossbar devices show switching ratios greater than 103, long retention times, and good endurance. The resistive switching in these devices is consistent with a combined filamentary/interfacial mechanism. Overall, ZTO shows great potential as a low cost material for embedding memristive memory with thin film transistor logic for large area electronics.
Highlights
► We present the first report of resistive switching in zinc–tin-oxide (ZTO).
► ZTO is the leading alternative material to IGZO for TFTs for LCDs.
► ZTO has an advantage over IGZO of lower cost due to the absence of In and Ga.
► Al/ZTO/Pt crossbar RRAM devices show switching ratios greater than 1000.
► ZTO shows promise for embedding RRAM with TFT logic for large area electronics.
### Lysosens life extension related research progress
This month, a paper reporting results from the LysoSENS project that SENS Foundation funds at Rice University will be published in the printed edition of Biotechnology and Bioengineering. (The paper is already available online.) The research that produced these results was primarily performed by Dr. Jacques Mathieu in the lab of Dr. Pedro Alvarez, in Rice University’s Department of Environmental Engineering. The project has focused on identifying enzymes that can degrade or modify 7-ketocholesterol (7KC) in the lysosomal environment. Because the cytotoxic effects of 7KC on the lysosomes of macrophages and foam cells are a root cause of atherosclerosis, such enzymes could ultimately be used in vivo as a new class of regenerative therapies to prevent and reverse heart disease.
The bacteria that express enzymes capable of degrading 7-KC, which is the objective of Lysosens. Lysosens is to remove junk that builds up in cells as a process of aging
Fightaging covers the progrss on Lysosens.
Given that many different harmful metabolic waste products exist, the field of biomedical remediation has enormous scope for growth - and certainly for more funding, which should hopefully start to arrive in the wake of proof of concept work like this. There is no need to slow down after finding one or more enzymes that break down 7-ketocholesterol, as firstly there could still be far better enzymes out there for this job, and secondly there remain numerous other damaging waste compounds in our cells and tissues that are worthy of biomedical remediation.
### Norway scientists commercialize semiconductors grown on graphene
Norwegian University of Science and Technology (NTNU) researchers report they have patented and are commercializing gallium arsenide (GaAs) nanowires grown on graphene, a hybrid material with competitive properties. Semiconductors grown on graphene are expected to become the basis for new types of device systems, and could fundamentally change the semiconductor industry.
Crayonano is the caompny commercializing the work.
The new patented hybrid material offers excellent optoelectronic properties, says Professor Helge Weman, a professor at NTNU's Department of Electronics and Telecommunications, and CTO and co-founder of the company created to commercialize the research, CrayoNano AS. "We have managed to combine low cost, transparency and flexibility in our new electrode," he adds.
The patented method of growing semiconductor nanowires on atomically thin graphene uses molecular beam epitaxy (MBE) to grow the nanowires.
"We do not see this as a new product," Weman says. "This is a template for a new production method for semiconductor devices. We expect solar cells and light emitting diodes to be first in line when future applications are planned."
Nanoletters - Vertically Aligned GaAs Nanowires on Graphite and Few-Layer Graphene: Generic Model and Epitaxial Growth
### Laser-powered ‘Needle’ Promises Pain-free Injections
A new laser-based system blasts microscopic jets of drugs into the skin could soon make getting a shot as painless as being hit with a puff of air.
The system uses an erbium-doped yttrium aluminum garnet, or Er:YAG, laser to propel a tiny, precise stream of medicine with just the right amount of force. This type of laser is commonly used by dermatologists, “particularly for facial esthetic treatments,” says Jack Yoh, professor of mechanical and aerospace engineering at Seoul National University in South Korea, who developed the device along with his graduate students.
A time-lapse image showing a microjet fired from the laser-based injection system. Traveling through the air, the liquid in this experiment reaches a velocity of 30 meters per second (nearly 100 feet per second). Credit: Optics Letters.
Optics Letters - Er:YAG laser pulse for small-dose splashback-free microjet transdermal drug delivery
Other Needle Free Drug Delivery
The old series of Star Trek had a needle free hypospray. The hypospray has a real world counterpart called a jet injector, invented four years before the first Star Trek series debuted. It uses compressed air to inject the medication through the skin. However, unlike the hypospray, it carries the risk of cross-contamination, which has led to the jet injector falling into disuse. It also has limits for adjusting and controlling the exact dosage levels. The mechanisms used, particularly in spring-loaded designs, are one shot releases, with a coil that ejects the same amount of drug to the same depth every time, which limits the application to certain drugs or patient populations.
The U.S. Food and Drug Administration approved a device which uses ultrasonic waves to open pores on the skin, allowing the injection liquid to enter the bloodstream without the use of needles.
### Neural implant restores decision making capability in cocaine impaired monkeys
Technology Review - Researchers have used a neural implant to recapture a lost decision-making process in monkeys—demonstrating that a neural prosthetic can recover cognitive function in a primate brain. The results suggest that neural implants could one day be used to recover specific brain functions in patients with brain injuries or localized brain disease.
While the results of today's study may take many years to translate into humans, they suggest that even cognitive processes, such as deciding whether or not to grab a cup of coffee or remembering where you left your keys, could one day be augmented by brain chips.
Paralyzed patients have previously used brain implants and brain-machine interfaces to control robotic arms. And more than 80,000 Parkinson's patients around the world have a deep-brain stimulation implant, which functions like a pacemaker to reduce their tremors and other movement problems. In the new study, however, the implants could actually interpret neuronal inputs from one part of the brain and effectively communicate those outputs to another brain region.
More advanced versions of brain implants will eventually restore brain functions and memories in humans and could eventually lead to tranhumanist enhancement of brain function.
### Microstructural Improvements Enhance Material Properties
DARPA merges structural engineering principles with new fabrication technologies to demonstrate microstructural control of materials at the micron level.
Exquisite buildings like the Eiffel Tower were made possible because of advances in structural engineering design methods. Truss structures, like the Eiffel Tower, are highly efficient; they can carry the same loads as solid structures, but at approximately one tenth of the weight. This weight and strength advantage is also what enabled the dramatic increase in building heights between 1885 and 1930, when buildings went from an average of ten stories to more than 100 stories, as epitomized by the Empire State Building.
Drilling down a level to the materials that make up a structure, there is room again for dramatic improvements in strength, weight and other properties. With current technologies, materials are generally made using bulk processing methods. Bulk processing limits material properties because it provides insufficient control of the morphology, or form, within a material’s microstructure. The microstructure refers to the arrangement of the constituents that make up a material at the microscopic (material grain) level. The lack of full control in the microstructure allows for flaws in materials. However, if the limitations of bulk processing can be overcome, the range of material properties available might be greatly increased.
DARPA’s Materials with Controlled Microstructural Architecture (MCMA) program seeks these kinds of breakthroughs. In an attempt to overcome the limitations of bulk processing and achieve its goals, MCMA is combining engineering principles developed for large structures with emerging fabrication techniques to engineer and control the architecture of a material’s microstructure down to the micron level. This control allows researchers to develop materials with greatly enhanced properties. For instance, as demonstrated in the video below, DARPA was able to construct a material so light that it can rest atop a bubble. MCMA researchers are working toward the goal of developing a material that is as strong as steel, but as light as a plastic. To do so, they are exploring the full range of properties that can be manifested as functions of truss design and weight in a material’s microstructure.
### DARPA walking robot for carrying supplies is now ten times quieter
DARPA and Boston Dynamics walking robot LS3 systemunderwent its initial outdoor test earlier this year and has matured through continual testing and improvements to the point that two functioning platforms have started to run through the paces similar to what they could one day experience carrying gear for a squad of Marines or Soldiers. The goal of the LS3 program is to demonstrate that a legged robot can unburden dismounted squad members by carrying their gear, autonomously following them through rugged terrain, and interpreting verbal and visual commands.
The system will help a squad carry about 400 pounds of gear.
“We’ve refined the LS3 platform and have begun field testing against requirements of the Marine Corps,” said Army Lt. Col. Joe Hitt, DARPA program manager. “The vision for LS3 is to combine the capabilities of a pack mule with the intelligence of a trained animal.”
During today’s event, the LS3 prototype completed trotting and jogging mobility runs, perception visualization demonstration and a soldier-bounded autonomy demonstration.
Today’s demo also exhibited reduced noise levels for the robots. “LS3 is now roughly 10 times quieter than when the platform first came online, so squad members can carry on a conversation right next to it, which was difficult before,” Hitt said.
## September 13, 2012
### Nanoengineers can print 3D microstructure blood vessels in mere seconds
Nanoengineers at the University of California, San Diego have developed a novel technology that can fabricate, in mere seconds, microscale three dimensional (3D) structures out of soft, biocompatible hydrogels. Near term, the technology could lead to better systems for growing and studying cells, including stem cells, in the laboratory. Long-term, the goal is to be able to print biological tissues for regenerative medicine. For example, in the future, doctors may repair the damage caused by heart attack by replacing it with tissue that rolled off of a printer.
NanoEngineering Professor Shaochen Chen has demonstrated the capability of printing three-dimensional blood vessels in mere seconds out of soft, biocompatible hydrogels. Being able to print blood vessels is essential to achieving the promise of regenerative medicine because it is how the body distributes oxygen and nutrients. Image Credit: Biomedical Nanotechnology Laboratory, Chen Research Group, UC San Diego Jacobs School of Engineering.
Advanced Materials - Rapid Fabrication of Complex 3D Extracellular Microenvironments by Dynamic Optical Projection Stereolithography
### A slow shift from World War 2 Radar to GPS for US Air Traffic Control
WSJ - A high-tech overhaul to the nation's air traffic control system is mostly on track to completion, but has yet to produce the benefits that airlines and passengers were told to expect, federal investigators say. Progress in moving from preparation to execution has been slow as the Federal Aviation Administration replaces its World War II-era radar technology with a GPS-based system.
Lacking return on their investment, airlines are reluctant to continue making the multibillion-dollar equipment upgrades needed for the new system to work.
After years of delays and cost overruns, the FAA has improved its handling of the modernization program, known as NextGen, Scovel said. But the agency still hasn't established its overall costs or timeline.
By 2020, the new system is expected to reduce delays by 38 percent compared with the current system; airlines, passengers and taxpayers are estimated to save $24 billion. The FAA plans to spend$2.4 billion over the next five years on a collection of six programs that the agency says will revolutionize air travel by moving from an outdated, radar-based system to one that uses satellite technology for precision tracking. The goal is to move planes faster and more efficiently by making routes more direct, eliminating many weather delays and enabling planes to fly safely at closer distances.
Once fully in place, the modernization program will save 1.4 billion gallons of fuel and reduce carbon dioxide emissions by 14 million metric tons.
Planes must be equipped with new technology, such as navigational equipment, at a cost of hundreds of thousands of dollars per aircraft. NextGen, however, doesn't start yielding full benefits until a critical mass of planes have the new technology, so nobody wants to go first.
Most of the previous scrutiny of the modernization effort has focused on ERAM, the main computer system air traffic controllers will use to identify and track aircraft, except right before takeoff and landing. After a four-year delay and a cost overrun of $330 million, the computer system is up and running in nine cities and on track to be used in all sites by 2014. But software glitches persist, including some that send data to the wrong aircraft. Those issues have had a domino effect, throwing off implementation of other NextGen elements that depend on the computer system and eating up FAA dollars intended for other functions. ### US Federal Reserve Starts QE3 and promises zero interest rate to mid-2015 1. Bloomberg - The United States Federal Reserve said it will expand its holdings of long-term securities with open-ended purchases of$40 billion of mortgage debt a month in a third round of quantitative easing as it seeks to boost growth and reduce unemployment.
“If the outlook for the labor market does not improve substantially, the committee will continue its purchases of agency mortgage-backed securities, undertake additional asset purchases and employ its other policy tools as appropriate,” the Federal Open Market Committee said today in a statement at the end of a two-day meeting in Washington.
The FOMC said it would probably hold the federal funds rate near zero “at least through mid-2015.” Since January, the Fed had said the rate was likely to stay low at least through late 2014.
### Engineers at the University of Southampton have built a supercomputer from 64 Raspberry Pi computers and Lego
A team, led by Professor Simon Cox, consisted of Richard Boardman, Andy Everett, Steven Johnston, Gereon Kaiping, Neil O’Brien, Mark Scott and Oz Parchment, along with Professor Cox’s son James Cox (aged 6) who provided specialist support on Lego and system testing created a 64 Raspberry Pi supercomputer.
The machine, named “Iridis-Pi” after the University’s Iridis supercomputer, runs off a single 13 Amp mains socket and uses MPI (Message Passing Interface) to communicate between nodes using Ethernet. The 64 units have 24 GFLOPs for a theoretical peak of 1.5 TeraFLOPs.
The racking was built using Lego with a design developed by Simon and James, who has also been testing the Raspberry Pi by programming it using free computer programming software Python and Scratch over the summer. The machine, named “Iridis-Pi” after the University’s Iridis supercomputer, runs off a single 13 Amp mains socket and uses MPI (Message Passing Interface) to communicate between nodes using Ethernet. The whole system cost under £2,500 (excluding switches) and has a total of 64 processors and 1Tb of memory (16Gb SD cards for each Raspberry Pi). Professor Cox uses the free plug-in ‘Python Tools for Visual Studio’ to develop code for the Raspberry Pi.
Professor Cox adds: “The first test we ran – well obviously we calculated Pi on the Raspberry Pi using MPI, which is a well-known first test for any new supercomputer.”
The steps to make the computer are here
The machine uses linux and Python.
### Intel Bets on Moore's Law for Another Decade
PC Mag -Intel is readying 14-nanometer process technology for chips due out next year and sees a path all the way to 5nm processors by the end of the decade, Intel senior fellow Mark Bohr said Wednesday.
The chip giant is currently ramping its 22nm process with third-generation Core chips known as Ivy Bridge that were first released in late 2011. Comfortably ensconced in the high-volume stage of 22nm production, Bohr said defect density in Intel's 22nm silicon have improved considerably and yields are now matching the previous 32nm generation of products.
Bohr said extreme ultraviolet (EUV) lithography would be preferable for the 10nm node, but it probably wouldn't be cost-effective at that point.
Beyond 10nm, Intel has pegged 7nm and 5nm transistors as the next stops on the Moore's Law-driven path to ever-smaller circuitry packed more densely onto computer chips every 18 months or so.
ZD Net - Jack Clark picture from the IDF 2012 talk
### Intel to Software Developers: Embrace Era of Transparent Computing
at the Intel Developer Forum (IDF), Renée James, senior vice president and general manager of the Software and Services Group at Intel Corporation, outlined her vision for transparent computing. This concept is made possible only through an “open” development ecosystem where software developers write code that will run across multiple environments and devices. This approach will lessen the financial and technical compromises developers make today.
Intel now believes that HTML5 is emerging as a credible solution for several of the technical challenges that we outlined around the vision for transparent computing.
“With transparent computing, software developers no longer must choose one environment over another in order to maintain profitability and continue to innovate,” said James. “Consumers and businesses are challenged with the multitude of wonderful, yet incompatible devices and environments available today. It’s not about just mobility, the cloud or the PC. What really matters is when all of these elements come together in a compelling and transparent cross-platform user experience that spans environments and hardware architectures. Developers who embrace this reality are the ones who will remain relevant.”
Software developers are currently forced to choose between market reach, delivering innovation or staying profitable. By delivering the best performance with Intel's cross-platform tools, security solutions and economically favorable distribution channels, the company continues to take a leadership position in defining and driving the open software ecosystem.
* Intel reinforces commitment to ensuring HTML5 adoption accelerates and remains an open standard, providing developers a robust application environment that will run best on Intel® architecture.
* New McAfee Anti-Theft product is designed to protect consumers’ property and personal information on Ultrabook™ devices.
* The Intel® Developer Zone is a new program designed to provide software developers and businesses with a single point of access to tools, communities and resources to help them engage with peers.
### Intel sees economical quad-patterned path to 10 nm chips and plans to get to 5nm
EETimes - Intel Corp. has found a way to create a 10 nm process technology using immersion lithography. In addition, the processor giant is on track to start making chips in a 14 nm process technology before the end of next year, said an Intel fellow in a talk at the Intel Developer Forum.
The 10 nm process would debut in 2015 or later. It would require quadruple patterning for some mask layers but “it’s still economical,” said Mark Bohr, director of Intel’s technology and manufacturing group.
Intel is considering many options including ones not on this slide Bohr showed.
### ABC Conjecture has a serious claim to a proof
Wikipedia - The abc conjecture (also known as Oesterlé–Masser conjecture) is a conjecture in number theory, first proposed by Joseph Oesterlé (1988) and David Masser (1985) as an integer analogue of the Mason–Stothers theorem for polynomials. The conjecture is stated in terms of three positive integers, a, b and c (whence comes the name), which have no common factor and satisfy a + b = c. If d denotes the product of the distinct prime factors of abc, the conjecture essentially states that d is rarely much smaller than c.
The abc conjecture has already become well known for the number of interesting consequences it entails. Many famous conjectures and theorems in number theory would follow immediately from the abc conjecture. Goldfeld (1996) described the abc conjecture as "the most important unsolved problem in Diophantine analysis".
In August 2012, Shinichi Mochizuki released a paper with a serious claim to a proof of the abc conjecture. Mochizuki calls the theory on which this proof is based inter-universal Teichmüller theory, and it has other applications including a proof of Szpiro's conjecture and Vojta's conjecture.
Here is the 61 page working paper of the proof. Inter-Universal Techmuller Theory IV: Log-Volume Computations and
Set-Theoretic Foundations
Some consequences
The abc conjecture has a large number of consequences. These include both known results, and conjectures for which it gives a conditional proof.
* Thue–Siegel–Roth theorem on diophantine approximation of algebraic numbers
* Fermat's Last Theorem for all sufficiently large exponents (proven in general by Andrew Wiles)
* The Mordell conjecture (Elkies 1991)
* The Erdős–Woods conjecture except for a finite number of counterexamples (Langevin 1993)
* The existence of infinitely many non-Wieferich primes (Silverman 1988)
* The weak form of Marshall Hall's conjecture on the separation between squares and cubes of integers (Nitaj 1996)
* The Fermat–Catalan conjecture, a generalization of Fermat's last theorem concerning powers that are sums of powers (Pomerance 2008)
* The L function L(s,(−d/.)) formed with the Legendre symbol, has no Siegel zero (this consequence actually requires a uniform version of the abc conjecture in number fields, not only the abc conjecture as formulated above for rational integers)
* P(x) has only finitely many perfect powers for integral x for P a polynomial with at least three simple zeros.[5]
* A generalization of Tijdeman's theorem
* It is equivalent to the Granville–Langevin conjecture.
* It is equivalent to the modified Szpiro conjecture, which would yield a bound of \operatorname{rad}(abc)^{\frac{6}{5}+\epsilon} (Oesterlé 1988).
* Dąbrowski (1996) has shown that the abc conjecture implies that n! + A= k2 has only finitely many solutions for any given integer A.[clarification needed]
While the first group of these have now been proven, the abc conjecture itself remains of interest, because of its numerous links with deep questions in number theory.
### Lunar Space elevator kickstarter at $107,500 with 2 hours to go With 2 hours to go the Liftport Lunar space elevator kickstarter is at$107,500
Different Fund Raising Levels in Brief
$20,000 - better sensors$30,000 - at least 3 to 5 kilometer
$50,000 - new robot and at least 3 to 5 kilometer$75,000 - transition from altitude to endurance
$100,000 - back in business for real$250,000 - try for to climb to the limit of balloon technology , about 20 miles / 30 kilometers
$500,000 - tests with plants and animals at 30 kilometers$3,000,000 - Full feasibility study and tests
The Skycube Kickstarter made it to $116,890 On August 30th, 2012, Skycube are announced a new stretch goal of$110,000. They made it.
## September 12, 2012
### iPhone 5 Announced and will be available September 21
Apple has officially introduced the iPhone 5 and has a comparison to other iPhones.
iPhone 5 on the left and compared to the iPhone 4S and iPhone 4.
In the US, all three iPhones will be available on AT&T, Sprint and Verizon.
The iPhone 5 has a 4-inch (diagonal) Retina display with 1136-by-640 resolution.
The iPhone 4 and iPhone 4S had 3.5-inch (diagonal) Retina display and 960-by-640 resolution.
### Inducing superconductivity in a semi-conductor with Scotch Tape
An international team led by University of Toronto physicists has developed a simple new technique to induce high-temperature superconductivity in a semiconductor for the first time - using Scotch Tape.
The method paves the way for new devices that could be used in quantum computing and to improve energy efficiency.
“Who would have thought simply sticking things together can generate entirely new effects?” said team leader and U of T physicist Ken Burch.
High-temperature superconductors are materials that conduct electricity without heating up or losing energy at liquid nitrogen temperatures. Used to transmit electricity with low loss, these superconductors are also the building blocks of the next generation of devices such as quantum computers.
Nature Communications - Proximity-induced high-temperature superconductivity in the topological insulators Bi2Se3 and Bi2Te3
### China High Speed Rail Sufficiently Profitable for the New Expansions
Four of the nation’s 14 high-speed rail lines have been profitable eversince bullet trains started full-speed, intercity service in China two years ago, giving impetus to a Ministry of Railways expansion.
Passenger ticket revenues have so far matched expenses — including debt payments — for the busy Beijing-Tianjin, Shanghai-Nanjing, Beijing-Shanghai and Shanghai-Hangzhou lines, a source at the National Development and Reform Commission (NDRC) told Caixin.
The financial health of the Beijing-Shanghai line exceeded expectations during its first operating year, which ended in June.
### Evidence for granular room-temperature superconductivity in water-treated graphite powder
Arxiv - Can doping graphite trigger room temperature superconductivity? Evidence for granular high-temperature superconductivity in water-treated graphite powder Trying to dope graphite flakes we found that the magnetization of pure, several tens of micrometers grain size graphite powder and after a simple treatment with pure water shows clear and reproducible granular superconducting behavior with a critical temperature above 300K. The observed magnetic characteristics as a function of temperature, magnetic field and time, provide evidence for weakly coupled grains through Josephson interaction, revealing the existence of superconducting vortices.
Technology Review has coverage.
## September 11, 2012
### China's central and local governments plans 12.6 trillion RMB (Over US$2 trillion) in spending Forbes - Weak economic data from the world’s second largest economy continues to stoke fears that as China slows down, it will exacerbate the cooling of the global economy. But it shouldn’t be all gloom and doom, according to Nomura’s economic research team, which suggests Chinese output will rebound sharply in the fourth quarter on the back of a stimulus plan worth about one trillion RMB ($158 billion) and monetary easing by the People’s Bank of China.
While GDP is expected to grow only 7.7% in the third quarter, Nomura’s research team forecasts a sharp rebound in the fourth quarter, with output expanding 8.8%. Infrastructure investment will play a prominent role in this recovery. Total planned investment for new projects started in August rose 33% year-over-year in August, up from 25% in the previous month; it’s forecasted to grow more than 40% this year.
Power stations, wind farms, airports, water supply, sewage treatment, and waste incineration power plant projects have also been announced, worth together around one trillion RMB, Nomura’s estimates show, or 2.1% of GDP. These projects take an average of four years to complete, and are normally started with a three to four month lag, they explained.
Local governments have also pledged about 11.6 trillion RMB in development projects that last anywhere from three to five years to complete. That translates into $1.83 trillion or 23% of GDP, dwarfing the four trillion RMB 2008 fiscal stimulus. While it isn’t entirely clear that these projects will indeed go through in the long run, Nomura expects investments in several of these to pick up over the coming months. China's local government and central government infrastructure and development projects are going to be about US$2 trillion over four years.
The United States has an eleven month budget deficit of 1.17 trillion. The United States will likely have another \$4 trillion in new deficit spending for the next four years.
### 25 kilometer tall towers for single stage to orbit launches
High Altitude Launch for a Practical SSTO (6 pages, 2003 by Geoffrey A. Landis and Vincent Denis)
Existing engineering materials allow the construction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. High-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2% of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated into increased payload capability to orbit, ranging from 5 to 20% increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2% of gross lift-off weight, this corresponds to 31% increase in payload (for 5-km launch altitude) to 122% additional payload (for 25-km launch altitude).
Example calculations of mass required for a fifteen-km tower sized to support a 2000 ton launch weight:
Structural material: Graphite epoxy:
LL = 107.5 km No taper needed
tower mass 280 tons
Cast steel:
LL = 15.4 km taper required
tower mass 5300 tons
(area taper ratio 2.6)
### Osamu Tabata – DNA origami for assembling nanomachines
Bio-pro.de - Cells, receptor proteins, enzymes and DNA have outstanding properties. The question is, can they also be used as building blocks in computer processors, sensor systems and other micromachines in next generation microelectronics? In cooperation with his research group at the University of Kyoto and his partners in Freiburg, Prof. Dr. Osamu Tabata, microengineer and External Senior Fellow at the Freiburg Institute for Advanced Studies (FRIAS) is working on the development of a new generation of micromachines based on folded DNA molecules that is smaller, more intelligent and better than the previous generation.
Prof. Osamu Tabata, External Senior Fellow at the School of Soft Matter Research at the Freiburg Institute for Advanced Studies (FRIAS) is a pioneer of MEMS.
The future of the art of engineering
Biological elements such as cells, receptor proteins, enzymes and DNA have amazing properties: they can recognize individual molecules, conduct light energy and catalyze chemical reactions, to name just a few properties. “Can they be used as components of next-generation microelectronics systems such as computer processors, sensor systems, MEMS and other micromachines?” asks Tabata, who is a professor in the Department of Microengineering Sciences at Kyoto University in Japan. “And how can biological elements be combined with microelectronic systems?” Tabata is certain that bionanotechnology will have a huge impact on engineering in the future. Currently focused on the basic aspects, it is such visions that have driven his research from the very beginning back in the day when the term “microelectromechanical systems” had not yet been coined.
The DNA origami method enables the researchers to fold DNA molecules into complicated scaffolds. (© Prof. Dr. Osamu Tabata)
### Estimate of 81.8 million new cars and trucks in 2012 and just over 1 billion old and new vehicles on the roads of the world
Production of passenger vehicles (cars and light trucks) rose from 74.4 million in 2010 to 76.8 million in 2011—and 2012 may bring an all-time high of 80 million or more vehicles, according to new research conducted by the Worldwatch Institute (www.worldwatch.org) for its Vital Signs Online service. Global sales of passenger vehicles increased from 75.4 million to 78.6 million over the same period, with a projected 81.8 million in 2012.
An estimated 691 million passenger cars were on the world’s roads in 2011. When both light- and heavy-duty trucks are included, the number rises to 979 million vehicles, which was 30 million more than just a year earlier. By the end of 2012, the global fleet could top 1 billion vehicles—one for every seven people on the planet.
## September 10, 2012
### Harold White Warp Field Mechanics Update
Space Warp equations are being tested using an instrument called the White-Juday Warp Field Interferometer. At Johnson Space Center, Eagleworks has initiated an interferometer test bed that will try to generate and detect a microscopic instance of a little warp bubble. Although this is just a tiny instance of the phenomena, it will be existence proof for the idea of perturbing space time—a “Chicago pile” moment, as it were. Recall that December of 1942 saw the first demonstration of a controlled nuclear reaction that generated a whopping half watt. This existence proof was followed by the activation of a ~ four megawatt reactor in November of 1943. Existence proof for the practical application of a scientific idea can be a tipping point for technology development.
In the past, the literature has quoted Jupiter amounts of exotic matter/negative pressure necessary to implement a “useful” warp bubble, making the idea mostly of academic interest at best. However, sensitivity analysis started by White in 2011 and completed this year has shown that the energy requirements can be greatly reduced by first optimizing the warp bubble thickness, and further by oscillating the bubble intensity to reduce the stiffness of space time. The results, to be presented at the 2012 100 Year Starship Symposium in Houston, will discuss the findings in detail, but have yielded a reduction from Jupiter amount of exotic matter to an amount smaller than the Voyager 1 spacecraft (500kg) for a 10-meter bubble with an effective velocity of 10c, which is a handy improvement.
The Eagleworks Q-thruster experiment attempts to utilize applied scientific research in the fields of quantum vacuum, gravitation, the nature of space-time, and other fundamental phenomenon to realize the possibility of an ultra-high Isp propulsion solution. Through these underpinnings, it is mathematically possible to employ the vacuum particle/anti-particle “sea” and utilize it as propellant reaction mass. Previous QVPT tests have generated possible thrust signals in the milli-Newton range and hinted at Isp’s on the order of 10^12 seconds. This iteration aims to validate or refute the present evidence in order to push forward in pursuit of breakthrough propulsion physics. For the exhibit, we will present a conceptual visualization of these effects, and provide a summary of present data and future plans.
Talk Polywell comment -
A "boost" of 100, combined with a 'starter velocity' of 0.1c, yields an apparent velocity of 10c.
100 * 0.1 = 10
Talk Polywell has a comment from Paul March who has worked on Mach Effect propulsion and nuclear propulsion.
If Dr. White's 4D+ theoretical conjecture on this warp field topic is correct, and I say if for we have no data yet to back it up until our back-ordered replacement laser shows up in the lab, we should be able to make the required inertially exotic mass requirement as small as desired dependent on the selected starting velocity, desired boost factor and how fast we can vary the warp-field's potential energy field about its mean value, which is dependent on how much power our RF generators can handle. However the higher the effective boost velocity becomes, the more ac potential energy one has to store in the warp-field and we all know what can happen to pressure vessels when they are pushed too far...
We have covered the initiation of this project 6 months ago.
### Skycube Kickstarter
Skycube is a nano-satellite that lets you take Earth images and "tweet" from space, then inflates a visible balloon, and de-orbits cleanly.
They have 25 hours left on their kickstarter.
Friend of Nextbigfuture, Chris Phoenix is writing the onboard software for Skycube.
Who Are We? And What is SkyCube?
We're the makers of the SkySafari astronomy apps for iOS, Android, and Mac OS X, and the SkyFi wireless telescope controller. With our mobile apps, we've revolutionized the way people observe the night sky. Now, we want to do for space exploration what we've done for amateur astronomy.
SkyCube will take low-resolution pictures of the Earth and broadcast simple messages uploaded by sponsors. After 90 days, it will use an 8-gram CO2 cartridge to inflate a 10-foot (3-meter) diameter balloon coated with highly reflective titanium dioxide powder. SkyCube's balloon will make the satellite as bright as the Hubble Space Telescope or a first-magnitude star. You'll be able to see it with your own eyes, sailing across the sky. But SkyCube's balloon isn't just for visibility. It will - within 3 weeks - bring SkyCube down from orbit due to atmospheric drag, ending the mission cleanly in a fiery "grand finale" that avoids any buildup of space debris.
SkyCube: Your Eye in the Sky
SkyCube won't just let you broadcast messages from space. It will also let you look back at the Earth from orbit. You can request images from the satellite using our smartphone or web app. SkyCube's images will be transmitted to our ground stations when the satellite passes over them - and then forwarded to you across the internet. You might just see your entire state (or country!) in one image from space, or catch a sunrise from orbit.
### Built-in Germanium Lasers could make Computer Chips faster
Paul Scherrer Institute (PSI) researchers have investigated how they could make the semiconductor Germanium emit laser light. As a laser material, Germanium together with Silicon could form the basis for innovative computer chips in which information would be transferred partially in the form of light. This technology would revolutionise data streaming within chips and give a boost to the performance of electronics. The researchers have demonstrated that Germanium must be put under strain by an external force in order to turn it into a laser material.
Low energy and highly efficient onchip photonic communications is a key technology to enable zettaflop supercomputers
Physical Review Letters - Direct-Gap Gain and Optical Absorption in Germanium Correlated to the Density of Photoexcited Carriers, Doping, and Strain
### Details of the NASA NIAC Water Walls Proposal
Space Architect - Water Walls Architecture: Massively Redundant and Highly Reliable Life Support For Long Duration Exploration Missions (14 pages, 2010)
This project has received phase 1 NASA NIAC funding in 2012.
The history of life support systems in space shows that mechanical life support systems have high duty cycles and consequent failure rates that make them problematic for long duration missions. Water Walls offers the potential for a largely passive system based on forward osmosis processes that will be much more reliable for long duration human exploration missions. Water Walls can also provide nutrient production and radiation shielding
Water Walls (WW) presents a new approach to long duration life support. Instead of providing one or two heavy, excessively complex and, sensitive, expensive, and failure-prone pieces of mechanical equipment, the WW approach provides a large number of simple units based on forward osmosis (FO) to handle the same functions as conventional systems – and more.
Instead of continuously active mechanical systems, WW is mostly passive, with only valves and small pumps as active elements – no compressors, evaporators, sublimators, distillers, adsorbers, or desorbers. Instead of the failureprone mechanical Environmental Control and Life Support System (ECLSS) equipment that must operate continuously, WW modules are designed to have their capacity consumed gradually throughout the mission. As one unit is used up, the next in line takes over. In the case of the blackwater/solids cells, they leave a residue of dry biomass and CaCO3 that can continue to provide radiation shielding.
An interplanetary spacecraft would launch with its WW modules dry, then in Low Earth Orbit (LEO) or at an Earth-Moon Lagrange Point, they would be primed with water to “fuel” the life support. WW offers the promise of an inexpensive, modular, simple, low maintenance, highly reliable, and massively redundant system to outfit human interplanetary spacecraft, lunar, and Mars bases. Between interplanetary missions or for scheduled maintenance at a lunar/planetary base, crewmembers refurbish the Water Walls systems simply by replacing the disposable FO bags or membranes.
### Metamaterial Antenna Satellite Internet hotspot company
Metamaterials Surface Antenna Technology (MSA-T) was invented by Intellectual Ventures, where a dedicated team of engineers performed significant research and development to de-risk the technology.
and this has been spunoff into Kymeta Corporation.
They want to use satellites to create Internet hotspots. The first application will be for airlines sometime in 2015. Kymeta would then develop products for trains and ships. They also want to create a small, backpack-sized satellite hot spot that could be used by the average consumer
Kymeta wants to be able install broadband satellite antennas onto planes, ships and trains in 24 hours. This will give mobile broadband to passengers (who are willing to pay for the privilege.).
## September 09, 2012
### Infrared LEDs made from Quantum dots
A new process developed by Dr. Liangfeng Sun and his team holds promise for improving the production and capabilities of the infrared light emitting diode, or LED, for use in technologies ranging from communications to night vision devices used by the military.
Sun, a Bowling Green State University assistant professor in physics and astronomy who also joined BGSU’s Center for Photochemical Sciences last year, and his team have pioneered a chemistry-based method of creating infrared LEDs in the lab using nanocrystals in solution, which has produced record brightness and better performance at a dramatically lower cost.
### Brayton Cycle Supercritical turbine
Sandia National Laboratories is seeking an industry partner to market a turbine system that could substantially improve energy efficiency in small modular nuclear reactors.
The system uses carbon dioxide in a closed-loop “Brayton-cycle” turbine to crank up electric conversion from heat, said Gary Rochau, manager of the advanced nuclear concepts group at Sandia’s Nuclear Energy and Fuel Cycle Technologies Center.
A supercritical CO2 Brayton-cycle system can reach 50 percent conversion efficiency. Typically, you only get 30 percent conversion with an [air-based] steam engine.
The system is much less expensive to build because it’s very compact, Rochau said. Given its size, it can’t be used in large power plants like coal-fired generators. But it’s well-suited for tiny plants, such as small modular nuclear reactors.
Sandia researchers have worked with this single compressor €œresearch loop to build a closed-loop Brayton-cycle turbine that uses supercritical carbon dioxide to increase the conversion of heat to electricity in turbine generators | {"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": 0.2957842946052551, "perplexity": 3671.7821256652664}, "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/1413558067467.26/warc/CC-MAIN-20141017150107-00004-ip-10-16-133-185.ec2.internal.warc.gz"} |
http://www.gradesaver.com/the-crucible/q-and-a/act-iii-95189 | # ACT III
Marry Warren's testimony is destroyed in the end because she cannot do something. What? How does she explain the problem? | {"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": 0.858491837978363, "perplexity": 5162.570588417241}, "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/1484560281151.11/warc/CC-MAIN-20170116095121-00213-ip-10-171-10-70.ec2.internal.warc.gz"} |
https://math.libretexts.org/TextMaps/Calculus/Book%3A_Calculus_(OpenStax)/12%3A_Vectors_in_Space/12.6%3A_Quadric_Surfaces | Skip to main content
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12.6: Quadric Surfaces
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We have been exploring vectors and vector operations in three-dimensional space, and we have developed equations to describe lines, planes, and spheres. In this section, we use our knowledge of planes and spheres, which are examples of three-dimensional figures called surfaces, to explore a variety of other surfaces that can be graphed in a three-dimensional coordinate system.
Identifying Cylinders
The first surface we’ll examine is the cylinder. Although most people immediately think of a hollow pipe or a soda straw when they hear the word cylinder, here we use the broad mathematical meaning of the term. As we have seen, cylindrical surfaces don’t have to be circular. A rectangular heating duct is a cylinder, as is a rolled-up yoga mat, the cross-section of which is a spiral shape.
In the two-dimensional coordinate plane, the equation $$x^2+y^2=9$$ describes a circle centered at the origin with radius $$3$$. In three-dimensional space, this same equation represents a surface. Imagine copies of a circle stacked on top of each other centered on the z-axis (Figure $$\PageIndex{1}$$), forming a hollow tube. We can then construct a cylinder from the set of lines parallel to the z-axis passing through circle$$x^2+y^2=9$$ in the xy-plane, as shown in the figure. In this way, any curve in one of the coordinate planes can be extended to become a surface.
Figure $$\PageIndex{1}$$: In three-dimensional space, the graph of equation $$x^2+y^2=9$$ is a cylinder with radius $$3$$ centered on the z-axis. It continues indefinitely in the positive and negative directions.
Definition: cylinders and rulings
A set of lines parallel to a given line passing through a given curve is known as a cylindrical surface, or cylinder. The parallel lines are called rulings.
From this definition, we can see that we still have a cylinder in three-dimensional space, even if the curve is not a circle. Any curve can form a cylinder, and the rulings that compose the cylinder may be parallel to any given line (Figure $$\PageIndex{2}$$).
Figure $$\PageIndex{2}$$: In three-dimensional space, the graph of equation $$z=x^3$$ is a cylinder, or a cylindrical surface with rulings parallel to the y-axis.
Example $$\PageIndex{1}$$: Graphing Cylindrical Surfaces
Sketch the graphs of the following cylindrical surfaces.
1. $$x^2+z^2=25$$
2. $$z=2x^2−y$$
3. $$y=\sin x$$
Solution
a. The variable $$y$$ can take on any value without limit. Therefore, the lines ruling this surface are parallel to the y-axis. The intersection of this surface with the xz-plane forms a circle centered at the origin with radius $$5$$ (see Figure $$\PageIndex{3}$$).
Figure $$\PageIndex{3}$$: The graph of equation $$x^2+z^2=25$$ is a cylinder with radius $$5$$ centered on the y-axis.
b. In this case, the equation contains all three variables —$$x,y,$$ and $$z$$— so none of the variables can vary arbitrarily. The easiest way to visualize this surface is to use a computer graphing utility (Figure $$\PageIndex{4}$$).
Figure $$\PageIndex{4}$$
c. In this equation, the variable $$z$$ can take on any value without limit. Therefore, the lines composing this surface are parallel to the z-axis. The intersection of this surface with the yz-plane outlines curve $$y=\sin x$$ (Figure $$\PageIndex{5}$$).
Figure $$\PageIndex{5}$$: The graph of equation $$y=sinx$$ is formed by a set of lines parallel to the z-axis passing through curve $$y=sinx$$ in the xy-plane.
Exercise $$\PageIndex{1}$$:
Sketch or use a graphing tool to view the graph of the cylindrical surface defined by equation $$z=y^2$$.
Hint
The variable $$x$$ can take on any value without limit.
Answer
When sketching surfaces, we have seen that it is useful to sketch the intersection of the surface with a plane parallel to one of the coordinate planes. These curves are called traces. We can see them in the plot of the cylinder in Figure $$\PageIndex{6}$$.
Definition: traces
The traces of a surface are the cross-sections created when the surface intersects a plane parallel to one of the coordinate planes.
Traces are useful in sketching cylindrical surfaces. For a cylinder in three dimensions, though, only one set of traces is useful. Notice, in Figure $$\PageIndex{6}$$, that the trace of the graph of $$z=\sin x$$ in the xz-plane is useful in constructing the graph. The trace in the xy-plane, though, is just a series of parallel lines, and the trace in the yz-plane is simply one line.
Figure $$\PageIndex{6}$$: (a) This is one view of the graph of equation $$z=sinx$$. (b) To find the trace of the graph in the xz-plane, set $$y=0$$. The trace is simply a two-dimensional sine wave.
Cylindrical surfaces are formed by a set of parallel lines. Not all surfaces in three dimensions are constructed so simply, however. We now explore more complex surfaces, and traces are an important tool in this investigation.
Quadric Surfaces
We have learned about surfaces in three dimensions described by first-order equations; these are planes. Some other common types of surfaces can be described by second-order equations. We can view these surfaces as three-dimensional extensions of the conic sections we discussed earlier: the ellipse, the parabola, and the hyperbola. We call these graphs quadric surfaces
Definition: Quadric surfaces and conic sections
Quadric surfaces are the graphs of equations that can be expressed in the form
$Ax^2+By^2+Cz^2+Dxy+Exz+Fyz+Gx+Hy+Jz+K=0.$
When a quadric surface intersects a coordinate plane, the trace is a conic section.
An ellipsoid is a surface described by an equation of the form $$\frac{x^2}{a^2}+\frac{y^2}{b^2}+\frac{z^2}{c^2}=1.$$ Set $$x=0$$ to see the trace of the ellipsoid in the yz-plane. To see the traces in the y- and xz-planes, set $$z=0$$ and $$y=0$$, respectively. Notice that, if $$a=b$$, the trace in the xy-plane is a circle. Similarly, if $$a=c$$, the trace in the xz-plane is a circle and, if $$b=c$$, then the trace in the yz-plane is a circle. A sphere, then, is an ellipsoid with $$a=b=c.$$
Example $$\PageIndex{2}$$: Sketching an Ellipsoid
Sketch the ellipsoid
$\frac{x^2}{2^2}+\frac{y^2}{3^2}+\frac{z^2}{5^2}=1.$
Solution
Start by sketching the traces. To find the trace in the xy-plane, set $$z=0: \frac{x^2}{2^2}+\frac{y^2}{3^2}=1$$ (Figure $$\PageIndex{7}$$). To find the other traces, first set $$y=0$$ and then set $$x=0.$$
Figure $$\PageIndex{7}$$: (a) This graph represents the trace of equation $$\frac{x^2}{2^2}+\frac{y^2}{3^2}+\frac{z^2}{5^2}=1$$ in the xy-plane, when we set $$z=0$$. (b) When we set $$y=0$$, we get the trace of the ellipsoid in the xz-plane, which is an ellipse. (c) When we set $$x=0$$, we get the trace of the ellipsoid in the yz-plane, which is also an ellipse.
Now that we know what traces of this solid look like, we can sketch the surface in three dimensions (Figure $$\PageIndex{8}$$).
Figure $$\PageIndex{8}$$: (a) The traces provide a framework for the surface. (b) The center of this ellipsoid is the origin.
The trace of an ellipsoid is an ellipse in each of the coordinate planes. However, this does not have to be the case for all quadric surfaces. Many quadric surfaces have traces that are different kinds of conic sections, and this is usually indicated by the name of the surface. For example, if a surface can be described by an equation of the form
$\frac{x^2}{a^2}+\frac{y^2}{b^2}=\frac{z}{c}$
then we call that surface an elliptic paraboloid. The trace in the xy-plane is an ellipse, but the traces in the xz-plane and yz-plane are parabolas (Figure $$\PageIndex{9}$$). Other elliptic paraboloids can have other orientations simply by interchanging the variables to give us a different variable in the linear term of the equation $$\frac{x^2}{a^2}+\frac{z^2}{c^2}=\frac{y}{b}$$ or $$\frac{y^2}{b^2}+\frac{z^2}{c^2}=\frac{x}{a}$$.
Figure $$\PageIndex{9}$$: This quadric surface is called an elliptic paraboloid.
Example $$\PageIndex{3}$$: Identifying Traces of Quadric Surfaces
Describe the traces of the elliptic paraboloid $$x^2+\frac{y^2}{2^2}=\frac{z}{5}$$.
Solution
To find the trace in the xy-plane, set $$z=0: x^2+\frac{y^2}{2^2}=0.$$ The trace in the plane $$z=0$$ is simply one point, the origin. Since a single point does not tell us what the shape is, we can move up the z-axis to an arbitrary plane to find the shape of other traces of the figure.
The trace in plane $$z=5$$ is the graph of equation $$x^2+\frac{y^2}{2^2}=1$$, which is an ellipse. In the xz-plane, the equation becomes $$z=5x^2$$. The trace is a parabola in this plane and in any plane with the equation $$y=b$$.
In planes parallel to the yz-plane, the traces are also parabolas, as we can see in Figure $$\PageIndex{10}$$.
Figure $$\PageIndex{10}$$: (a) The paraboloid $$x^2+\frac{y^2}{2^2}=\frac{z}{5}$$. (b) The trace in plane $$z=5$$. (c) The trace in the xz-plane. (d) The trace in the yz-plane.
Exercise $$\PageIndex{2}$$:
A hyperboloid of one sheet is any surface that can be described with an equation of the form $$\frac{x^2}{a^2}+\frac{y^2}{b^2}−\frac{z^2}{c^2}=1$$. Describe the traces of the hyperboloid of one sheet given by equation $$\frac{x^2}{3^2}+\frac{y^2}{2^2}−\frac{z^2}{5^2}=1.$$
Hint
To find the traces in the coordinate planes, set each variable to zero individually.
Answer
The traces parallel to the xy-plane are ellipses and the traces parallel to the xz- and yz-planes are hyperbolas. Specifically, the trace in the xy-plane is ellipse $$\frac{x^2}{3^2}+\frac{y^2}{2^2}=1,$$ the trace in the xz-plane is hyperbola $$\frac{x^2}{3^2}−\frac{z^2}{5^2}=1,$$ and the trace in the yz-plane is hyperbola $$\frac{y^2}{2^2}−\frac{z^2}{5^2}=1$$ (see the following figure).
Hyperboloids of one sheet have some fascinating properties. For example, they can be constructed using straight lines, such as in the sculpture in Figure $$\PageIndex{1a}$$. In fact, cooling towers for nuclear power plants are often constructed in the shape of a hyperboloid. The builders are able to use straight steel beams in the construction, which makes the towers very strong while using relatively little material (Figure $$\PageIndex{1b}$$).
Figure $$\PageIndex{11}$$: (a) A sculpture in the shape of a hyperboloid can be constructed of straight lines. (b) Cooling towers for nuclear power plants are often built in the shape of a hyperboloid.
Example $$\PageIndex{4}$$: Chapter Opener: Finding the Focus of a Parabolic Reflector
Energy hitting the surface of a parabolic reflector is concentrated at the focal point of the reflector (Figure $$\PageIndex{12}$$). If the surface of a parabolic reflector is described by equation $$\frac{x^2}{100}+\frac{y^2}{100}=\frac{z}{4},$$ where is the focal point of the reflector?
Figure $$\PageIndex{12}$$: Energy reflects off of the parabolic reflector and is collected at the focal point. (credit: modification of CGP Grey, Wikimedia Commons)
Solution
Since z is the first-power variable, the axis of the reflector corresponds to the z-axis. The coefficients of $$x^2$$ and $$y^2$$ are equal, so the cross-section of the paraboloid perpendicular to the z-axis is a circle. We can consider a trace in the xz-plane or the yz-plane; the result is the same. Setting $$y=0$$, the trace is a parabola opening up along the z-axis, with standard equation $$x^2=4pz$$, where $$p$$ is the focal length of the parabola. In this case, this equation becomes $$x^2=100⋅\frac{z}{4}=4pz$$ or $$25=4p$$. So p is $$6.25$$ m, which tells us that the focus of the paraboloid is $$6.25$$ m up the axis from the vertex. Because the vertex of this surface is the origin, the focal point is $$(0,0,6.25).$$
Seventeen standard quadric surfaces can be derived from the general equation
$Ax^2+By^2+Cz^2+Dxy+Exz+Fyz+Gx+Hy+Jz+K=0.$
The following figures summarizes the most important ones.
Figure $$\PageIndex{13}$$: Characteristics of Common Quadratic Surfaces: Ellipsoid, Hyperboloid of One Sheet, Hyperboloid of Two Sheets.
Figure $$\PageIndex{14}$$: Characteristics of Common Quadratic Surfaces: Elliptic Cone, Elliptic Paraboloid, Hyperbolic Paraboloid.
Example $$\PageIndex{5}$$: Identifying Equations of Quadric Surfaces
Identify the surfaces represented by the given equations.
1. $$16x^2+9y^2+16z^2=144$$
2. $$9x^2−18x+4y^2+16y−36z+25=0$$
Solution
a. The $$x,y,$$ and $$z$$ terms are all squared, and are all positive, so this is probably an ellipsoid. However, let’s put the equation into the standard form for an ellipsoid just to be sure. We have
$16x^2+9y^2+16z^2=144.$
Dividing through by 144 gives
$\frac{x^2}{9}+\frac{y^2}{16}+\frac{z^2}{9}=1.$
So, this is, in fact, an ellipsoid, centered at the origin.
b. We first notice that the $$z$$ term is raised only to the first power, so this is either an elliptic paraboloid or a hyperbolic paraboloid. We also note there are $$x$$ terms and $$y$$ terms that are not squared, so this quadric surface is not centered at the origin. We need to complete the square to put this equation in one of the standard forms. We have
$$9x^2−18x+4y^2+16y−36z+25=0$$
$$9x^2−18x+4y^2+16y+25=36z$$
$$9(x^2−2x)+4(y^2+4y)+25=36z$$
$$9(x^2−2x+1−1)+4(y^2+4y+4−4)+25=36z$$
$$9(x−1)^2−9+4(y+2)^2−16+25=36z$$
$$9(x−1)^2+4(y+2)^2=36z$$
$$\frac{(x−1)^2}{4}+\frac{(y−2)^2}{9}=z.$$
This is an elliptic paraboloid centered at $$(1,2,0).$$
Exercise $$\PageIndex{3}$$:
Identify the surface represented by equation $$9x^2+y^2−z^2+2z−10=0.$$
Hint
Look at the signs and powers of the $$x,y$$, and $$z$$ terms
Answer
Hyperboloid of one sheet, centered at $$(0,0,1)$$.
Key Concepts
• A set of lines parallel to a given line passing through a given curve is called a cylinder, or a cylindrical surface. The parallel lines are called rulings.
• The intersection of a three-dimensional surface and a plane is called a trace. To find the trace in the xy-, yz-, or xz-planes, set $$z=0,x=0,$$ or $$y=0,$$ respectively.
• Quadric surfaces are three-dimensional surfaces with traces composed of conic sections. Every quadric surface can be expressed with an equation of the form
$Ax^2+By^2+Cz^2+Dxy+Exz+Fyz+Gx+Hy+Jz+K=0.$
• To sketch the graph of a quadric surface, start by sketching the traces to understand the framework of the surface.
• Important quadric surfaces are summarized in Figures $$\PageIndex{13}$$ and $$\PageIndex{14}$$.
Glossary
cylinder
a set of lines parallel to a given line passing through a given curve
ellipsoid
a three-dimensional surface described by an equation of the form $$\frac{x^2}{a^2}+\frac{y^2}{b^2}+\frac{z^2}{c^2}=1$$; all traces of this surface are ellipses
elliptic cone
a three-dimensional surface described by an equation of the form $$\frac{x^2}{a^2}+\frac{y^2}{b^2}−\frac{z^2}{c^2}=0$$; traces of this surface include ellipses and intersecting lines
elliptic paraboloid
a three-dimensional surface described by an equation of the form $$z=\frac{x^2}{a^2}+\frac{y^2}{b^2}$$; traces of this surface include ellipses and parabolas
hyperboloid of one sheet
a three-dimensional surface described by an equation of the form $$\frac{x^2}{a^2}+\frac{y^2}{b^2}−\frac{z^2}{c^2}=1;$$ traces of this surface include ellipses and hyperbolas
hyperboloid of two sheets
a three-dimensional surface described by an equation of the form $$\frac{z^2}{c^2}−\frac{x^2}{a^2}−\frac{y^2}{b^2}=1$$; traces of this surface include ellipses and hyperbolas
quadric surfaces
surfaces in three dimensions having the property that the traces of the surface are conic sections (ellipses, hyperbolas, and parabolas)
rulings
parallel lines that make up a cylindrical surface
trace
the intersection of a three-dimensional surface with a coordinate plane | {"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": 0.9108176827430725, "perplexity": 320.67060946088947}, "config": {"markdown_headings": false, "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-2018-26/segments/1529267864958.91/warc/CC-MAIN-20180623113131-20180623133131-00605.warc.gz"} |
http://stackoverflow.com/questions/3001593/random-value-from-flags-enum/3002313 | # Random value from Flags enum
Say I have a function that accepts an enum decorated with the Flags attribute. If the value of the enum is a combination of more than one of the enum elements how can I extract one of those elements at random? I have the following but it seems there must be a better way.
[Flags]
enum Colours
{
Blue = 1,
Red = 2,
Green = 4
}
public static void Main()
{
var options = Colours.Blue | Colours.Red | Colours.Green;
var opts = options.ToString().Split(',');
var rand = new Random();
var selected = opts[rand.Next(opts.Length)].Trim();
var myEnum = Enum.Parse(typeof(Colours), selected);
Console.WriteLine(myEnum);
}
-
var options = Colours.Blue | Colours.Green;
var matching = Enum.GetValues(typeof(Colours))
.Cast<Colours>()
.Where(c => (options & c) == c) // or use HasFlag in .NET4
.ToArray();
var myEnum = matching[new Random().Next(matching.Length)];
-
You can call Enum.GetValues to get an array of the enum's defined values, like this:
var rand = new Random();
Colors[] allValues = (Colors[])Enum.GetValues(typeof(Colors));
Colors value = allValues[rand.Next(allValues.Length)];
-
I would like a random value of only a subset of the enum as defined by a bitwise combination like "Blue | Red". Sorry for not being clearer. – Chris Porter Jun 9 '10 at 0:07
If you don't mind a little casting, and your enum is of underlying int type, the following will work and is fast.
var rand = new Random();
const int mask = (int)(Colours.Blue | Colours.Red | Colours.Green);
If you only want a single flag to be set, you could do the following:
var rand = new Random();
return (Colours)(0x1 << (rand.Next(3)));
-
If the result of "(int)allValues & rand.Next()" is zero, and you do not have a zero enum member, you get an invalid enum i.e. (Colours)0. – Tim Lloyd Jun 8 '10 at 22:53
True. Let me see if it can be fixed... – bbudge Jun 8 '10 at 23:10
OK, I think it works now. But it got a little messier and less clear. Only useful if performance is a serious concern. – bbudge Jun 8 '10 at 23:32
This works, but I particularly wanted only one value returned. Sorry if that wasn't clear. Your solution returns combinations like "Blue | Red | Green" – Chris Porter Jun 9 '10 at 0:04
Added code for that, albeit with ugly "magic" numbers. With that, I'm done with this question! – bbudge Jun 9 '10 at 0:28
If I understand correctly, the question is about returning a random enum value from a flags enum value, not returning a random member from a flags enum.
[Flags]
private enum Shot
{
Whisky = 1,
Absynthe = 2,
Pochin = 4,
BrainEraser = Whisky | Absynthe | Pochin
}
[Test]
public void Test()
{
Shot myCocktail = Shot.Absynthe | Shot.Whisky;
Shot randomShotInCocktail = GetRandomShotFromCocktail(myCocktail);
}
private static Shot GetRandomShotFromCocktail(Shot cocktail)
{
Random random = new Random();
Shot[] cocktailShots = Enum.GetValues(typeof(Shot)).
Cast<Shot>().
Where(x => cocktail.HasFlag(x)).ToArray();
Shot randomShot = cocktailShots[random.Next(0, cocktailShots.Length)];
return randomShot;
}
Edit
And obviously you should check that the enum is a valid value, e.g.:
Shot myCocktail = (Shot)666;
Edit
Simplified
-
You are correct in stating the problem. However I think your random function will not return the values with an even distribution. At a 50/50 chance for each value through the loop subsequent values have a lower chance of being selected ? – Chris Porter Jun 9 '10 at 0:01
I see your point. Strictly speaking it is still random and answers your question. I have updated it to an even distro. It is late and I'm sure I have probably stuffed up! :) – Tim Lloyd Jun 9 '10 at 0:11
And now simplified. – Tim Lloyd Jun 9 '10 at 0:26
Thanks for your efforts – Chris Porter Jun 9 '10 at 11:26
Not the answer you were looking for then? – Tim Lloyd Jun 9 '10 at 11:29 | {"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": 0.2259100377559662, "perplexity": 5846.957658292781}, "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/1422121981339.16/warc/CC-MAIN-20150124175301-00170-ip-10-180-212-252.ec2.internal.warc.gz"} |
https://help.windev.com/?2513006&name=condensed_property | ONLINE HELP WINDEV, WEBDEV AND WINDEV MOBILEVersion: 2425262728
Font variableLimits WINDEV WEBDEV WINDEV Mobile Others Condensed (Property) In french: Condensé Warning From version 27, this property is kept for backward compatibility. It is recommended to use the new CharacterSpacing property to manage character spacing. The Condensed property is used to:Determine whether a Font variable is condensed.Condense a Font variable.Remark: Stretched font characters can be:Normal: characters are normal.Condensed: characters are narrower (Condensed property).Extended: characters are wider (Extended property).Large: characters are as wide as possible (Large property).Example // Define the characteristics of a Font variableFont1 is FontFont1.Name = "Arial"Font1.Size = 14Font1.Condensed = True// Apply the font to "MyControl"MyControl.Font = Font1 Syntax Determining whether a Font variable is condensed = .Condensed : BooleanTrue if the specified font is condensed, False otherwise. : Font variableName of the Font variable to be used. Condensing a Font variable .Condensed = : Font variableName of the Font variable to be used. : BooleanTrue if the specified font must be condensed, False otherwise. Remarks Font variableA font can be created from a Font variable.To define the font characteristics, use:the FontCreate function,the Charset, Orientation, StrikeOut, Color, Extended, Bold, Italic, Large, Name, Underline and Size properties.This font can be used:To write text in drawings (dFont).To write in charts (grLabelFont, grLegendFont, grTitleFont and grAxisTitleFont).To print (iFont).In the controls of a window (Font property).In the controls of a report (Font property).LimitsThe properties that define character stretch options (Condensed, Extended and Large properties) are supported only if the specified Font variable is used for printing (print font or font of controls in a report).In the other cases (font used for the drawings, the charts or the window controls), these characteristics are ignored. See also Minimum version required Version 9 This page is also available for… | {"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": 0.9683793783187866, "perplexity": 15692.785243132052}, "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-2023-06/segments/1674764499831.97/warc/CC-MAIN-20230130232547-20230131022547-00257.warc.gz"} |
https://nerdburglars.net/steamachievementlist/run-rabbit-run | # Run Rabbit Run Achievement List
Make a 1000 jumps since the beginning of the game
Make a 5000 jumps since the beginning of the game
100 deaths since the beginning of the game
500 deaths since the beginning of the game
1000 death since the beginning of the game
5000 death since the beginning of the game
50 deaths since the beginning of the level
100 deaths since the beginning of the level
300 deaths since the beginning of the level
Collect 100k score since the beginning of the game
Collect 500k score since the beginning of the game
Collect the biggest carrot and open the second chapter
Past 5 levels in green time
Past 10 levels in green time
Past 20 level in green time
WOW, past 35 levels on green time
10 deaths from trains
50 deaths from spikes | {"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": 0.9230705499649048, "perplexity": 3865.9471139524517}, "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-2019-13/segments/1552912203093.63/warc/CC-MAIN-20190323221914-20190324003914-00003.warc.gz"} |
https://wiki.microfocus.com/index.php/GroupWise_8_Good_and_Bad_Habits | GroupWise 8 Good and Bad Habits
Introduction
This may well be where the rubber meets the road.
This section contains clever working examples, good advice, some warnings, and just plain criticisms. Tips of what to do, what not to do and tricks on extending your GroupWise services beyond the normal scopes are attempted. Hoping to help and preventing gotchas being the main theme .....
Global Good Habits
GroupWise System Configurations
• Lock system administration to the primary domain
• Do manage client settings at the domain level if possible
• Do manage or limit wild card addressing
As of GroupWise 8 SP2, there can be restrictions on the numbers of recipients and attachment types
As of GroupWise 8 SP2, Distribution Lists can have restrictions on who can send to them.
• Check agent queue directories from time to time for aged unprocessed files
For wpcsin and wpcsout subdirectories if a file is 24+ hours old it should be deleted (or looked into why, prior to deleting)
For the send, receive, and result directories used for the GWIA SMTP daemon if a file is 24+ hours old it should be deleted
MSLOCAL subdirectories for MTAs should be checked while all links are open and apply the same 24 hour rule, except for the \MSLOCAL\MSHOLD\xxxyyyy\ queues.
Internet Agent Configurations
All
• Do configure or disable the SMTP relay settings
• Do configure "Classes of Service" for any settings outside of the defaults for your system. Not only does it result in a modular implementation, but it presents a clear design picture for peer or juinor administrators
• Do provide POP or IMAP services using dedicated agents
• Do utilize the agent re-direction capabilities if multiple agents can or are used
• Do Disable unused protocols (LDAP, POP3, IMAP)
• Convert all Gateway Aliases to Internet Over-rides (Use Migration Tool provided in C1 GW Snapin)
• If the Client (1677) communication has been set to use SSL, ensure that you change the Post Office link to "Use Current Post Office Access" (shown as Follow PO) or POP3 & IMAP4 will fail
• Do ensure your attachment encoding method does not cause usability issues for clients. For instance a 20MB attachment will most likely be a 27MB file once it's MIME encoded. Subsequently it will be blocked by a 20 MB attachment limit. Don't make users do maths.
Linux
• Do ensure that the GWIA is bound to only the specified IP Address/DNS Host name - Postfix requires the loop-back address so as to function correctly for system messages.
WebAccess Agent Configurations
All
• Do patch the agent frequently to ensure viewer files are updated as they are updated by Novell
• Do utilize the agent re-direction capabilities if multiple agents can or are used
• Do Patch the host OS regularly as they will be attacked
• Do try regular Penetration Testing to ensure security is maintained.
• If the Client (1677) communication has been set to use SSL, ensure that you change the Post Office link to "Use Current Post Office Access" (shown as Follow PO) or WebAccess will fail
Linux
• LDAP services should be disabled on system startup on Web Access Application servers
• WebAccess Applications should be installed as 64 bit Linux instances to improve performance
NetWare
• Utilize restartable protected memory address spaces with meaningful names
• Ensure "Memory Protection Fault Cleanup" is set to "On" to so successful Document Viewer address space restarts can actually occur (and they will)
• Ensure "Memory Protection Restart Count" is set greater than "1" so multiple Document Viewer address space restarts actually can occur (and they will) without halting the agent or server
Message Transfer Configurations
All
• Do configure additional inbound connection allowances for heavily loaded agents using the /tcpinbound switch in the agent startup file
• Do configure domain links changes from the target domain
Post Office Agent Configurations
All
• Never use direct access for post office connection.... really.... ever.....
• Dedicate a POA(s) to document management services
• Where you have to have multiple Agents on one server, stagger the maintenance tasks
Linux
• Utilize the GroupWise High Availability feature in GW Monitor to manage the Linux agents to get restarted via gwha under xinetd
• Do enable the Document Conversion Agent (DCA) and configure the quarantine settings
NetWare
• Utilize restartable protected memory address spaces with meaningful names
• Disable the Document Conversion Agent (DCA) using the /nodca switch in the agent startup file
• Place the LDAPSDK, LDAPSSL and LDAPX NLMs included with your agent software version in the same directory as the agent application files
Server platform considerations
Linux server configurations
OES and SLES
• OpenMotif libraries (openmotif-libs):Provides the environments required for the GroupWise text based installation
• OpenMotif package (openmotif):Provides the environments required for the GroupWise GUI based installation
(The edit of the limits.conf below ONLY APPLIES to version 802HP2 or earlier. Version 802HP3 and later has resolved this where it automatically allocates the Open Files value for its process when it starts up.)
Configure open file limits on Linux servers by adding the following lines to the /etc/security/limits.conf file.
* soft nofile 8192
* hard nofile 65535
Configure the Postfix service to listen only on the local host interface by adding or modifying the following line to the /etc/postfix/main.cf file.
inet_interfaces=127.0.0.1
(Applies to version 802HP2 or earlier only. Version 802HP3 and later has resolved this slow performance issue in code by making a TCP/IP "No Delay" call.) There is a slow performance situation in the MTP file transfer when two or more agents are running on the same Linux server (Novell TID 7007575). The data transfer between any two agents on the same server using MTP will slow down to around 200,000 bytes/sec. This problem does not exist if the file transfer occurs between different Linux servers. To resolve this issue, configure the loopback transfer to adopt the same data transfer size of 1500, same as using the Ethernet NIC, by adding or modifying the following line to the "/etc/sysconfig/network/ifcfg-lo" file.
MTU='1500'
Once modified run the following command to restart the network service and put the changed MTU into effect:
sudo /etc/init.d/network restart
Once all of the the above is done, the speed returns to around 26,000,000 bytes/sec. (GroupWise
Its always a good idea to install and test available OES and SLES updates before installing GroupWise Support Pack or Hot Patch updates. It is possible that newer software has dependencies on updated core system files, libraries or applications. Minimally the documentation referencing the GroupWise software update should be evaluated for these requirements.
However, even these sources may not contain this information at times. So, when in doubt update and test core OS components prior to applying GroupWise software on OES and SLES hosts.
SSH service configuration
The SSH services running on POSIX systems offer a reasonable level of security in their default configurations. However, most organizations should implement some basic service configuration changes that will enhance the security SSH services.
The changes recommended here configure SSH to:
• Prevent the ability of user “root†to login via SSH
• Limits the use of service to SSH protocol version 2 only as version 1 has many documented security flaws
• The incorrect user login count is decremented to 3 for usability reasons however your security model may not agree with this change
These changes can be implemented for SSH daemons on OES Linux servers by modifying the proper directives in the “/etc/ssh/sshd_config†file.
sshd_config:
# Protocol 2,1
Protocol 2
# MaxAuthTries 6
MaxAuthTries 2
Disable unnecessary services
Regardless of the role of the target server it should be deployed with the minimal running application environment possible. Disabling unnecessary services conserves computational resources and reduces management overhead. Additionally the server is more easily hardened as a result not allowing unneeded services to start.
Good candidates for disabling are:
alsasound - Sound hardware daemon
apache2 - The Apache 2 http daemon (If not used for WebAccess)
auditd - Linux file system auditing daemon
nfsserver - NFS server daemon
nfsboot - NFS service daemon
nmb - netbios daemon
novell-tomcat5 - Novell implementation of the java application server
tomcat5 - Standard implementation of the java application server (If not used for WebAccess)
smb - Samba service daemon
portmap - NFS/NIS service daemon
splash - Splash screen setup
splash_early - Stops animations after the network starts
Disabling unnecessary Apache modules
The same logic for disabling and unloading unnecessary server applications and services can be applied to Apache modules as well. If the module is not running it does not need to be managed or secured.
With some degree of certainty there is a small subset of Apache server modules that can and should be disabled on most OES Linux and Suse Linux Enterprise servers. These primarily deal with file and database authentication and authorization services.
Modify the “APACHE_MODULES†directive in the “/etc/sysconfig/apache2†file to remove unnecessary modules from the server configuration and restart Apache.
For example remove the references for the following apache modules:
auth_basic
authn_file
authz_groupfile
authz_user
authn_dbm
suexec
userdir
** However the required module set for any specific server implementation can vary so do not remove any modules your implementation may require.
There are many configuration changes that can be implemented to further harden Apache instances on OES Linux and SuSE Linux Enterprise servers. However the suggestions here are minimum baseline configurations that are determined to be a good fit for the network environment that hosts the servers and services.
A simple change could be used to prevent Apache from serving certain types of files as HTTP content or for download. Some of these file types may contain server and service configuration information or other information the organization may not intend to publish. A file named “security.conf†containing the required directives could be created and placed in the “/etc/apache2/conf.d†directory of the target server. Apache on OES and SuSE Linux distributions is pre-configured to process all files that end in a “.conf†extension in this directory on service startup. This is the preferred method to make modular changes to Apache instances instead of modifying the primary httpd.conf file. Apache should be restarted after placing the file in the referenced directory.
The contents of the “security.conf†file are displayed below:
<Files ~ "\.(bak|old|~|2|copy|tmp|swp)$"> Order allow,deny Deny from all </Files> Some additional security steps can be implemented to instruct Apache not to divulge unnecessary information just because a client asks for it. An example of this would be the vendor and version of the operating system hosting the Apache instance. Instructing Apache to not declare the operating system provider used on its host is quite easy to do. Modify the “APACHE_SERVERTOKENS†directive in the in “/etc/sysconfig/apache2†file to be something other than "OS". It is recommended that you set it to “ProductOnly†so Apache only declares the Apache product and no version or OS info if interrogated by a client. After making the change restart the Apache service. Additional suggestions: • Disable logging for the “mod_rewrite†module if it is not being utilized beyond its default configuration • Modify the “/etc/apache2/listen.conf†file to configure the Apache service to listen on the primary server IP address instead of 0.0.0.0 Running agents in “User Space†is different GroupWise agents running on the Linux platform run as a user recognized on the local system. As with any other application running in user space, as opposed to kernel space†file system rights to the target file system are required for the application to run successfully. By default the local user “root†is used as the GroupWise agent's run time identity. For this case file system rights do not need to be adjusted. However it is not recommended to run your GroupWise agents as user root. Running GroupWise agents as non-root users Benefits: • Improves server and application security models (hackers love to interrupt applications running as root) • Improves service troubleshooting (If all applications are running as root.....) All GroupWise agents with the exception of the WebAccess agent can run as non-root users. There are two platform specific options for providing the non-root user your agents will run as. SLES: Use a locally configured user and group. Observations have indicated to use no more than eight lowercase characters for the names. Additionally, configure the users with a false shell and home directory (/bin/false, /home/false). OES: Use a locally known Linux User Management (LUM) enabled user. Observations have indicated to use no more than eight characters for the names. Additionally, configure the users with a false shell and home directory (/bin/false, /home/false). You cannot use a LUM enabled user for the GWHA service. Currently this user must be local on each server participating in the GWHA implementation. Once the non-root user is available to the system create a text file containing the non-root user name called “uid.conf†in the /etc/opt/novell/groupwise/agents directory. If the agent is already running shut it down and delete the existing “uid.run†file in the directory specified in it's “home†switch. Change the user and group ownership (setting the group ownership will not be possible for NSS volumes) of the files in the same directory to reflect the configured non-root user. Start or restart the target GroupWise agent. If non-root users are used for GroupWise agents it is important that instances of ConsoleOne used against those agents are run as the same user. If ConsoleOne is run as any other user, such as root, administrative messages may be placed in agent queues that it cannot process due to ownership issues. When non-root users are used be sure to set and monitor file and group ownerships on agent file systems. Be especially keen to observe for this issue post installation, following database rebuilds, or on the occasional agent restart. Configuring Servers to use the GroupWise High Availability Service The GroupWise High Availability Service (GWHA), and its configuration file, serves three purposes for a GroupWise agent. • It replaces the memory address space restart functionality used on the NetWare platform that promoted agent high availability. • When married with the GroupWise Monitor services GroupWise agents can be polled and restarted if the local GWHA services are properly configured. • It allows some additional control options for how the agent is started normally. • When the "show" argument is added to the gwha.conf file it can be enabled or disabled by the administrator to invoke the agent GUI for troubleshooting purposes The gwha.conf file is located in the /etc/opt/novell/groupwise directory. A commented example is displayed below. [gwha] ssl = no (no if not using SSL) key = filename.key (blank if not using SSL) cert = filename.crt (blank if not using SSL) password = key file password (blank if not using SSL) [domain_name] server = /opt/novell/groupwise/agents/bin/gwmta command = /etc/init.d/grpwise startup = /opt/novell/groupwise/agents/share/domain_name.mta delay = 2 wait = 10 ;show = yes (optional, yes starts agent with GUI and not as a daemon) [post_office_name.domain_name] server = /opt/novell/groupwise/agents/bin/gwpoa command = /etc/init.d/grpwise startup = /opt/novell/groupwise/agents/share/post_office_name.poa delay = 2 wait = 10 ;show = yes (optional, yes starts agent with GUI and not as a daemon) It is important that the case used for the GroupWise objects and their references in the gwha.conf file match. The print argument for the /etc/init.d/grpwise script displays the the settings specified in the /etc/opt/novell/groupwise/gwha.conf file /etc/init.d/grpwise print • It serves as a set of configuration variables for the /etc/init.d/grpwise script. • In order to keep this init script as vanilla as possible. Imagine if each agent had its own script on a server in a large clustered environment. The gwha.conf file stores the name and configuration information specific to each agent installed on the server. The "delay =" setting controls the length of time between when the script issues the command to start an agent and when the script displays a message indicating that the agent has started. The default delay time is 2 seconds. Under certain circumstances, an agent could encounter a problem and fail to start after 2 seconds. In this case, you would receive the success message but the agent would not be running. You need to increase the delay = setting to accommodate the length of time it typically takes for the agent to start successfully on your system. The "wait =" setting controls the length of time between when the script issues the command to stop an agent and when the script kills the agent if the agent has not yet stopped. The default wait time is 10 seconds. Under certain circumstances, an agent could take longer than 10 seconds to perform a normal shutdown, and killing the agent under those circumstances would not be appropriate. You need to increase the wait = setting to accommodate the length of time it usually takes for the agent to shut down. A message notifies you if the script kills an agent because its shutdown exceeds the wait = setting. Configuring a user account for GWHA services Using a Linux User Management (LUM) enabled user will not work for GWHA services. However using a local Linux user on each server the GWHA service will benefit the robustness of the service by isolating it from external account store dependencies. Configure a standard Linux user with a password and a primary group for GWHA to use. This user's credentials will be used by the GroupWise Monitor agent to interact with the GroupWise agent. No file system rights need be assigned. Ed Hanley's comment - I thought the xinetd credentials are used to interact with the GW Agent for restart and not the gwha account you create. Needs to be looked into. Configure the gwha user with a false shell and home directory Use "/bin/false" and "/home/false" for the user's shell and home directory parameters. Enable the High Availability service In order for the Target GroupWise agent to be HA aware it must be loaded when the HA environment is active on the server. • In YaST, click Network Services > Network Services (inetd). • If necessary, select Enable to activate the list of services. • Scroll down to the gwha line, select it, then click Toggle Status (On or Off) to change the status to On. • Click Finish. • Stop/re-start the GroupWise agents(s) To enable communication between the GroupWise Monitor Agent and the High Availability service, start the Monitor Agent with the the following switches minimally. Configure the Monitor Agent to communicate with the GWHA service Enable and modify the following section of the "/etc/init.d/grpwise-ma" script with the following switches and values. MA_OPTIONS="--hauser <gwha_user> --hapassword <password> --hapoll 120" Set to match the username and password of the Linux user you set up to represent the High Availability service on your Linux servers. --hauser --hapassword Also consider using the following switches --httpagentuser <agent_http_mgmt_port_user> --httpagentpassword <agent_http_mgmt_port_user_password> The "--httpagentuser" and "--httpagentpassword" switches provide the user names and passwords for your monitored GroupWise agents HTTP management ports to the Monitor Agent for enhances monitoring, reporting, and alarm features. Once the Monitor Agent is configured and restarted it will begin to poll the configured agents that are allowed through the service filter. The agents can also be manually polled through the agent interface to get status information between polling cycles or to restart a agent known to be stopped. Add or remove GroupWise agents from the agent filter by using the "Preferences" --> "Filter" navigation link menus. The GroupWise HA service and NCS When a GroupWise agent is installed into a Novell Clustering Services environment there is a caveat to be aware of. When an agent is failed or migrates to another node by the clustering software or a management action, the previous GWHA service is not aware of the agent's new good state on another node. We also have to disable the GWHA service during the NCS Unload process so the GW Monitor GWHA service does not try to start up the GW service that is being Stopped in the Unload script. To ensure the HA environments are normalized, the GWHA services on the previous node should be restarted so it is unaware of the agents previous state transition. This is best accomplished by restarting the GWHA service using the GroupWise cluster resource Unload script. Disable the gwha service at the beginning of the Unload script, unload the GroupWise agents, then re-enable the gwha service at the end of the Unload script. #! /bin/bash . /opt/novell/ncs/lib/ncsfunc # Disable the gwha service under xinetd ignore_error /sbin/chkconfig -s gwha off ignore_error kill -HUP pidof xinetd # Unload the GroupWise agents /etc/init.d/grpwise stop POA.DOMAIN # Unload other cluster stuff Volumes NCP Services IP addresses # Re-Enable the gwha service under xinetd ignore_error /sbin/chkconfig -s gwha on ignore_error kill -HUP pidof xinetd If you are using snmp (such as Cacti) to monitor disk free space clustered GroupWise volumes, you need to restart the snmpd daemon at the end of the cluster Load and Unload scripts so that when snmp queries the host the actual snmp object currently running will be reported. If a cluster volume is mounted on nodeA and is later migrated to nodeB without restarting the snmpd daemon, a snmp query to the server currently hosting the mount GroupWise resource will not know that a new snmp resouce is present and report erroneous numbers to the calling snmp application. # If you are using snmp monitoring. Add at end of # the Load and Unload scripts # Reload the snmpd daemon so the host recognizes # a new resource has been added /etc/init.d/xinetd restart Additional GroupWise Monitor Agent Configuration Configuring the GroupWise Monitor Agent can be a bit intimidating for some as it makes heavy use of startup switches. Fortunately, few are required to implement a very functional and useful service. For more information about the GroupWise Monitor Service Please see GroupWise Monitor use and scope In addition to the switches for the Monitor Agent startup script or file consider using the following switches as well. --hapoll <desired_polling_time_in_seconds> --monwork <path_to_monitor_work_directory> The --hapoll startup switch to control how often the Monitor Agent contacts the High Availability service with agent status information in seconds. Consider the amount of time suitable for your environment. Understanding that loaded agents may take longer to shut down. 90 - 180 seconds works well for most environments. The "--monwork" switch simply specifies where the the Monitor Agent places its application data to include maps and reports. By default it works from the "/temp" directory which is not desirable. Again it is recommended that you implement a live domain for the GroupWise Monitor service. Using this configuration your Monitor Agent can perform reporting and performance analysis tasks against your system. Do use the following switches if you incorporate a live domain as recommended into your Monitor service implementation: --home <path_to_monitor_domain_directory_> --ipa <ip_address_of_monitor_domain_mta> --ipp <tcp_port_of_monitor_domain_mta> NetWare It is better to have loved and lost than never to have loved at all... NetWare has entered extended support (which ends in March 2012) Pretty much every TID and GroupWise admin knows NetWare and what to do, so this section is light. NetWare 6.5 SP8 and Atime There was a new NSS switch added to NetWare 6.5 Service Pack 8 that allows Atime to be disabled at a persistent volume level. nss /noatime=gwdata Windows NTFS sucks - but we can improve it NTFS File System Ugly file system that it is, NTFS has managed to develop over time to quite a usable system. The inherent problems with fragmentation are designed deep into the code and therefore can never be resolved. For GroupWise on Windows this will require regular (every 6 Months?) de-fragmenting. Optimizing the File system can be done however and items to consider for this are: PagedPoolSize HKLM\System\CurrentControlSet\Control\SessionManager\MemoryManagement\ (REG_DWORD) File cache space and paged pool space share a common area in system virtual address . Limiting the paged pool allows for a larger system cache, which causes more content to be cached and allows faster serving of files. PagedPoolSize = 192000000 NtfsDisable8dot3NameCreation HKLM\System\CurrentControlSet\Control\FileSystem\ (REG_DWORD) Default is 0. This parameter determines whether NTFS generates a short name in the 8.3 (DOS) naming convention for long file names and for file names that contain characters from the extended character set. If the value of this entry is 0, files can potentially have two names: the name that the user specifies and the short name that NTFS generates. If the name the user specifies conforms to the 8.3 naming convention, NTFS does not generate a short name. NTFS File System Setting Under HKLM\System\CurrentControlSet\Control\FileSystem\ NtfsDisableLastAccessUpdate (REG_DWORD). This system-global switch reduces disk I/O load and latencies by disabling the updating of the date and time stamp for the last file or directory access. This key needs to be added; it does not exist by default. Disabling the updates is effective when used with large data sets (or a large number of hosts) containing thousands of directories. It is recommended that you use IIS logging instead if you maintain this information for Web administration only. Stripe unit size. Software solution is fixed at 64 KB. Hardware solutions may range from 4 KB to 1MB. Ideal stripe unit size maximizes the disk activity without unnecessarily breaking up requests (so that multiple disks are required to service a single request). For example: · One stream of sequential requests (large) on JBOD would keep only one disk busy at a time. To keep all disks busy, the stripe unit needs to be equal to 1/N where N is the request size. · For N streams of small random requests, if N is greater than the number of disks, and if there are no hotspots, striping will not increase performance. However, if there are hotspots, the stripe unit size needs to maximize the chance that a request will not be split, while minimizing the chance of a hotspot falling entirely within one or two stripe units. You might pick a low multiple of the request size, like 5X or 10X, especially if the requests are on some boundary (for example, 4 KB or 8 KB). · For fewer streams than disks, you need to split the streams so that all disks are kept busy. Interpolate from the previous two examples. For example, if you have 10 disks and 5 streams, split each request in half (use a stripe unit size equal to half the request size). Whenever possible use separate volumes for each data type. For example, use one volume for the operating system and paging space, and one or more volumes for shared user data, applications, and log files. Place different data types in separate volumes on different virtual disks. Using separate virtual disks is especially important for any data types that create heavy write loads, such as log files, so that a single set of disks (that compose the virtual disk) can be dedicated to handling the disk I/O created by the updates to the log files. Placing the paging file on a separate virtual disk can provide some minor improvements in performance, but typically not enough to make it worth the extra cost Disablelastaccess HKLM\System\CurrentControlSet\Control\FileSystem\. (REG_DWORD) By default, this registry key is not created. If you have an NTFS volume with a high number of folders or files, and a program is running that briefly accesses each of these in turn, the I/O bandwidth used to generate the Last Access Time updates can be a significant percentage of the overall I/O bandwidth. To increase the speed of access to a folder or file, you can set disablelastaccess to disable updating the Last Access Time. After you use this command and restart the computer, the Last Access Time is no longer updated. If you create a new file, the Last Access Time remains the same as the File Creation Time. CountOperations HKEY_LOCAL_MACHINE\System\CurrentControlSet\Session Manager\I/O System\CountOperations.(REG_DWORD) This parameter allows you to turn off system and process level I/O counters. This counter affects system and disk counting of disk and network I/O requests. Physical and logical disk counters—in addition to network interface, IP and TCP counters—are not affected by this parameter. It is useful to turn off the process and system counters by using this registry parameter on systems where there is a measurable cost associated with counting I/O at the process and system level but where I/O rates can still be analyzed at the physical, logical, network interface, IP and TCP levels. To turn off the process and system I/O counters, you need to create a registry value (and I/O System key if one doesn’t already exist) and set the value to 0 (REG_DWORD) in the following registry entry: A reboot is required for this setting to take effect. Process and system counters can be turned on again either by setting CountOperations to 1 or by removing the CountOperations registry entry. NumberOfRequests HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MINIPORT_ADAPTER\Parameters\DeviceN\NumberOfRequests (REG_DWORD) This parameter allows you to specify the number of SRBs created for a given adapter. This improves performance and allows Windows to give more disk requests to a logical disk, which is most useful for HW RAID adapters that have concurrency capabilities since each logical disk consists of multiple physical disks. However, the default setting is often less than optimal for many high-speed HW RAID disk arrays. Overall disk array performance can be improved by setting NumberOfRequests to a value in the range of 32 to 96 (decimal). Replace miniport_adapter with the specific adapter name. Make an entry for each device, and in each entry replace DeviceN with Device1, Device2, and so forth, depending on the number of devices you are adding. A reboot is required for this setting to take effect. For example, for two Emulex LP9000 miniport adapters whose miniport driver name is lp6nds35, you would create the following registry entries set to 96: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\lp6nds35\Parameters\Device0\NumberOfRequests HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\lp6nds35\Parameters\Device1\NumberOfRequests DontVerifyRandomDrivers HKEY_LOCAL_MACHINE\System\CurrentControlSet\Session Manager\Memory Management\DontVerifyRandomDrivers.(REG_DWORD) This parameter prevents the driver verifier from randomly verifying drivers for debugging. To disable the driver verifier set a value of 1 (REG_DWORD) for the following registry entry: NumTcbTablePartitions HKLM\system\CurrentControlSet\Services\Tcpip\Parameters\. (REG_DWORD) By default this key is not created. This parameter controls the number of TCB table partitions. The TCB table can be partitioned to improve scalability on multiprocessor systems by reducing contention on the TCB table. NumTcbTablePartitions = 8 TcpAckFrequency Note: TcpAckFrequency applies only to Windows 2003 and later and.XP Clients . For Gigabit cards: HKLM\system\CurrentControlSet\Services\Tcpip\Parameters\Interfaces (REG_DWORD) For each Gigabit adapter, add: TcpAckFrequency = 8 (decimal) By default this entry is not in the registry. If only acking data and not any control packets, ack once every 8 packets, instead of the default of 2. This helps reducing packet processing costs for the network stack in the case of large writes (uploads) from the server to client or client to server. Configuration Tips and Tricks Restricting your Internet Agent to talking to relay servers Implementation Purpose: To ensure the only machines that can transfer mail to your GWIA are your mail relay servers and your GroupWise MTA(s). Assumptions: You use a mail relay model within your environment. Your GWIA(s) is not configured to discover mail servers to send mail to. You explicitly direct it to another SMTP service to send mail through. You have open relay disabled on your GWIA(s). Benefits: You are able enforce which computers can connect to your Internet Agent to send mail. Facilitates service load balancing implementations. Doing so helps prevent your mail server(s) from being used to send mail from unauthorized internal systems or foreign systems. Some of this mail could even appear to come from your domain(s). You can send mail to another SMTP service that may provide enhanced SMTP services, service aggregation, throughput, or metrics gathering. Procedures: • Ensure you can disable the agents open relay option and do so. Select the "Prevent message relaying" option from the "Access Control" --> "SMTP Relay Settings" tab of the target Internet Agent object. If you need to allow some servers to relay mail from your server be sure to configure relay exceptions for them now. Alternatively you could implement a GWIA explicitly for them to use and configure exceptions for them there. • Edit the "Default Class of Service" on the "Access Control" tab. Under the "SMTP Incoming" tab select the "Prevent Incoming Messages" option. • In the "Exceptions" section create the following entries in the "Allow messages from:" column: • *@*.* • Blank-Sender-User-ID These entries are required for this configuration to work. Basically these records permit the agent to send outgoing messages and enable null sender message handling for incoming messages respectively. The latter messages include those used for listserv post notifications and other "do not reply" genre messages. We'll call it "querky" to be polite. • Also in the "Exceptions" section create entries in the "Allow messages from:" column for your relay server IP address(s) or DNS name(s). Now the only machines that can transfer mail to your Internet Agent are the relay servers and its respective MTA. Restricting your Internet Agents used for POP and IMAP to talking to load balancers Implementation Purpose: To ensure the only machines that can communicate with your GWIA using POP and IMAP protocols are your load balancers. Assumptions: Load balancers are, or will be, used within your environment. You have multiple GWIAs configured and dedicated to POP and IMAP clients installed on OES 2 or SLES 10 Linux instances Benefits: You are able enforce that which computers can connect to your Internet Agent to use POP and IMAP services. Prevention of service use by unauthorized systems, and improvement of service security and performance by authorized systems. Background Information: The introduction of load balancing in the infrastructure can help improve the quality of many services. Ensuring service resource consumption is evenly distributed, and even re-directed in the event of a server fault or a designed service demarcation can be useful in large environments. When the intention is to front end POP and IMAP services with load balancers you need to prevent clients from connecting to these agents directly. GroupWise provides no native tools that will allow you to restrict access to GWIA provided POP and IMAP services by network address. Additionally, most load balancers will allow you to implement "SSL Off-loading". This can also be thought of as SSL certificate aggregation. Using this feature will allow you to use a single SSL certificate for a service provided by multiple GWIAs. The use of SSL off-loading can unify multiple agent identities to secure the communication between clients and services. Conversly, the communication between the service and the load balancer(s) can be optimised by turning off SSL security entirely if the back end components are within the secured network perimeter. Procedures: The only way to implement this model currently is to utilise the local Suse Linux Enterprise Server firewall. The SLES 10 firewall allows all outgoing communication by default. So, what is required is to configure the inbound ports required by a normal server participating in a networked environment to communicate successfully. The chart below details the default protocols and ports that require configuration for OES 2 Linux servers. If the GroupWise Services are running on a SLES server a subset of the ports and protocols listed would be required. OES 2 Linux and GroupWise Protocols and Ports Service Protocol Ports Comments IMAP TCP 143 OES and SLES POP TCP 110 OES and SLES SMTP TCP 25 OES and SLES NTP UDP 123 OES and SLES SLP TCP/UDP 427 OES and SLES NCP TCP/UDP 524 OES LDAP TCP 389 OES and SLES LDAPs TCP 636 OES and SLES Novell Jetstream TCP 6901 OES NoRM TCP 8008 OES NoRM TCP 8009 OES iMonitor TCP 8028 OES iMonitor TCP 8030 OES SMDR TCP 40193 OES SSH TCP 22 OES and SLES wbem-https TCP 5989 OES GWMTA MTP TCP 7100 OES and SLES GWIA MTP TCP 7102 OES and SLES GWMTA HTTP TCP 7180 OES and SLES GWIA HTTP TCP 9850 OES and SLES GWHA TCP 8400 OES and SLES The easiest way to implement this configuration is to add the required ports to the appropiate sections of the /etc/sysconfig/SuSEfirewall2 file. FW_SERVICES_EXT_TCP="123 1500 1501 1578 1579 1581 22 389 40193 427 524 5989 636 6901 7100 7102 7180 8008 8009 8028 8030 9850" FW_SERVICES_EXT_UDP="123 427 524" The best way to implement the connectivity for the load balancers and GroupWise Monitor is to add them as trusted hosts using the appropiate section in the same file. FW_TRUSTED_NETS="<LOAD_BALANCER_IP_1>/32,tcp,110 <LOAD_BALANCER_IP_1>/32,tcp,143 <LOAD_BALANCER_IP_1>/32,tcp,25 <LOAD_BALANCER_IP_2>/32,tcp,110 LOAD_BALANCER_IP_2/32,tcp,143 LOAD_BALANCER_IP_2/32,tcp,25 <GWMONITOR_IP>,tcp,8400" Restart your local firewalls and verify your services are communicating as expected. If all is working well the result will be a server that can participate in the service provider role, service administration role, and network environment successfully. Also remember to add any other third party software ports to your firewall configuration. Enterprise monitoring and backup services are the first that come to mind. Configuring relay exceptions for your Internet Agent Implementation Purpose: To manage and authorize email relay operations for your GWIA(s) Benefits: GWIA email relay behavior is predictable, auditable and more secure Background Information: The best way to prevent abuse of your GroupWise Internet Agents from internal or external systems is to utilise public facing relay servers and access control tools. The previous section detailed how to manage the SMTP connections to your GWIA. This sections deals with the management of GWIA email relay behavior once a connection is allowed. Understanding the behavior of your agents is key to implementing a predictable configuration. The best way to accomplish this is by knowing the variables, testing and finally documenting. Consider the truth tables below that were developed using the following information: • The public facing relay server will only accept mail from iDomains known to the GroupWise system • GroupWise Internet Agents will deliver mail to known iDomains without a relay exception configured Relay Exception: "None" From To GWIA Relays or Delivers Relay Server Delivers NO N/A YES N/A YES N/A NO N/A (Used for internal delivery when no relay configuration is required) Relay Exception: "<Any Known iDomain>" From To GWIA Relays or Delivers Relay Server Delivers NO N/A YES N/A YES N/A NO N/A (Used for internal delivery when a relay configuration is required) Relay Exception: "*" From To GWIA Relays or Delivers Relay Server Delivers YES YES YES N/A YES N/A YES NO (Used for external delivery) This example may differ from your environment but the concepts will be the same. Good planning leads to good results. Configuring the WebAccess Agent for redirection and fault tolerance Implementation Purpose: To use two or more WebAccess Agents to redirect users to a specific agent and provide alternate ones in the event the preferred is not available. Assumptions: There are multiple WebAccess Application instances and Agents already available and properly configured for normal operation within your environment. Having multiple WebAccess Application instances on different network addresses, and possibly even load balanced using hardware or software would be a huge positive. Benefits: Users are directed to a preferred WebAccess Agent when they log in. If the primary is not available the alternate will assume the work. If the primary fails whilst the user is logged in the user is migrated to the alternate agent. Since the session stuff is managed by the web application server this is transparent to the user. The best part is when the primary agent becomes available again the user migrates back. Awesome. Procedures: • Ensure all target WebAccess agent encryption keys are identical. This is imperative as redirection will not work without completing this step. The field containing the encryption key used by the agent can be found on the "WebAccess" tab for the agent object in ConsoleOne. • For Linux servers modify the "/var/opt/novell/groupwise/webaccess/webacc.cfg" file manually to place the following entries in the "# Values added by install to update config file" section near the end of the file. Ensuring no other matching entries exist or conflict. For NetWare and Windows the path to the webacc.cfg will be different will be different. Provider.GWAP.Default.address.1=<webaccess_agent_1_network_address>:7205 Provider.GWAP.Default.address.2=<webaccess_agent_2_network_address>:7205 Provider.GWAP.Default.address.3=<webaccess_agent_3_network_address>:7205 Manually modifying the webacc.cfg files disregards convention in respect to using the WebAccess Application Objects to perform this task. Since the objects are simply a front end for the file changes administrators should use their best judgment for choosing a method to use for this change. • Using ConsoleOne add a primary WebAccess Agent override to the desired post offices. • Again using ConsoleOne add a second WebAccess agent override to the post office parent domain to serve as an alternate agent • The GroupWise Access Provider list specified in the webacc.cfg files for the application servers will ensure the tertiary agent is made available to users as it is the last configured component in the agent list hierarchy. • Restart the WebAccess Application services and agents to put the new configurations into effect and test. Forcing WebAccess URL paths to use HTTPS Implementation Purpose: To force URLs that contain http:<web_server_address>/gw/<anything_else>/ on Linux GroupWise WebAccess Application servers to use an https:// form of the URL. Prerequisites: • A configured Linux Apache web server with the GroupWise WebAccess Application installed • The mod_rewrite Apache module is installed on the Linux server instance (ussually this is the default configuration for OES and SLES servers) Procedures: Apache on OES and Suse Linux distributions is pre-configured to process all files that end in a “.conf†extension in "/etc/apache/conf.d" directory on service startup. This is the preferred method to make modular changes to Apache instances instead of modifying the primary httpd.conf file. Apache should be restarted after placing the file in the referenced directory. • A file named “gw-https.conf†containing the required directives could be created and placed in the “/etc/apache2/conf.d†directory of the target server. The contents of the proposed “gw-https.conf†file are displayed below: # HTTP_HOST is a variable that represents your web server address and shouldn't be changed. # Turning the rewrite Engine on may not be required RewriteEngine On RewriteCond %{REQUEST_URI} ^\/gw RewriteRule ^/(.*) https://%{HTTP_HOST}/$1 [NC,R,L]
Your WebAccess URL on this server should now re-direct to HTTPS regardless of the URL address form used by user browsers.
Configuring a clustered NetWare WebAccess Agent to use SSL certificates
Implementation Purpose:
To successfully configure the HTTP management port for the GroupWise WebAccess agent to use SSL services when being accessed.
Prerequisites:
• You have a functioning clustered WebAcess agent(s) running on the NetWare platform
• You have properly configured SSL certificate files accessible to the agent
• You receive 8209 "path not found" errors when you configure the SSL certificate for the agent
Oh ... and the agent won't load unless you disable the SSL configuration.
Benefits:
Obviously, using SSL when you communicate with, and authenticate to, the agent management port and secure inter-agent communications when configured.
Procedures:
The problem here is that for some reason the NetWare WebAccess agent won't use the NCP Virtual Server name in the certificate file path. Instead use the cluster volume format for the certificate path in the "SSL" configuration section for the WebAccess agent object.
For example:
<CLUSTER_VOLUME_NAME>:\path\to\certificate\file.b64
<CLUSTER_VOLUME_NAME>:\path\to\certificate\file.key
Then configure complete the normal SSL configuration for the agent and restart it.
If the agent starts its a very good sign and most likely reflects a good result.
Using NFS to extend GroupWise SDD hosted on Linux
Implementation Purpose: To make a SDD on an OES Linux clustered Posix volume available to servers and clients outside of the cluster
Assumptions: The volume containing the SDDs are available to all required nodes within NCS cluster
Prerequisites:
• A configured Posix file system cluster resource in a OES Linux NCS Cluster
• A SDD or set of SDDs configured within that file system
Procedures:
Create the cluster"able" NCP volume resource:
• Configure a branch of the POSIX file system to hold your SDD(s) you want available over NCP. This means copying the platform appropriate software to directories within that file system as well.
• Configure a NCP share on the POSIX cluster according to the following instructions:
• Create a NCP share by issuing the following command on the server where the shared storage is currently mounted:
ncpcon create volume <NCP_VOLUME_NAME> <SHARE_POSIX_PATH>
Use case standards that match your institutional standards for the NCP volume objects and verify the volume object was created in the target server context using the <SERVER_NAME>_<NCP_VOLUME_NAME> format. Use the following command to verify the volume was created and mounted
ncpcon volumes
• Edit the /etc/opt/novell/ncpserv.conf and remove the reference to the newly created NCP volume
• Restart the eDirectory daemon after modifying the ncpserv.conf file using the following command:
/etc/init.d/ndsd stop && /etc/init.d/ndsd start
• Restart the NCP/NSS IPC daemon after modifying the ncpserv.conf file using the following command:
/etc/init.d/ncp2nss stop && /etc/init.d/ncp2nss start
• Create a virtual NCP server object for the new NCP volume using the following command:
/opt/novell/ncs/bin/ncs_ncpserv.py -c <NCP_VIRTUAL_SERVER_NAME> -i <NCS_CLUSTER_RESOURCE_IP_ADDRESS>
• Verify the virtual NCP server object was created successfully
• Modify the new Virtual NCP server object using iManager and add the “NCS: Volumes†attribute to the object
• Edit the "NCS: Volumes" attribute by adding the NCP volume object representing the NCP share as the value for the attribute
• Modify the new NCP Volume object which is located in the same context as the server it was created on
• Edit the "hostServer" attribute to match the name and context of the target NCP virtual server object
• Rename the virtual NCP server and NCP volume object to match the institutional standards for your organization
Cluster NCP volume resource:
• Modify the NCS cluster load script with the following italicised entries
#!/bin/bash
. /opt/novell/ncs/lib/ncsfuncs
RESOURCE_IP=10.6.11.48
# define the file system type
MOUNT_FS=ext3
#define the container name
container_name=emailresources
# define the device
MOUNT_DEV=/dev/evms/$container_name/emailresources # define the mount point MOUNT_POINT=/media/posix/emailresources # define NCP volume NCP_VOLUME=EMAILRESOURCES # define NCP server name NCP_SERVER=EMAILRESOURCES #activate the container exit_on_error activate_evms_container$container_name $MOUNT_DEV # mount the POSIX file system ignore_error mkdir -p$MOUNT_POINT
exit_on_error mount -t $MOUNT_FS$MOUNT_DEV $MOUNT_POINT # add the IP address exit_on_error add_secondary_ipaddress$RESOURCE_IP
# mount the NCP volume
exit_on_error ncpcon mount $NCP_VOLUME=210,PATH=/media/posix/emailresources/ncp-share # bind the NCP volume exit_on_error ncpcon bind --ncpservername=$NCP_SERVER --ipaddress=$RESOURCE_IP exit 0 Replace volume mgr container, network address, NCP server, volume names, and NCP_VOLUME values with your own • Modify the NCS cluster unload script with the following italicized entries #!/bin/bash . /opt/novell/ncs/lib/ncsfuncs # define the IP address RESOURCE_IP=10.6.11.48 #define the container name container_name=emailresources # define the mount point MOUNT_POINT=/media/posix/emailresources # define NCP volume NCP_VOLUME=EMAILRESOURCES # define NCP server name NCP_SERVER=EMAILRESOURCES # unbind the NCP volume ignore_error ncpcon unbind --ncpservername=$NCP_SERVER --ipaddress=$RESOURCE_IP # dismount the NCP volume ignore_error ncpcon dismount$NCP_VOLUME
#dismount the POSIX volume
exit_on_error ncs_dismount $MOUNT_POINT # del the IP address ignore_error del_secondary_ipaddress$RESOURCE_IP
#deport the container
exit_on_error deport_evms_container $container_name # return status exit 0 Replace volume mgr container, network address, NCP server, volume names, and NCP_VOLUME values with your own • Test your clustered NCP share and move on when all is working as expected • Compose a script similar to the one below to export the desired SDD(s) over NFS #! /bin/bash # Enable NFS Shares /etc/init.d/portmap start /etc/init.d/nfsserver start # Load NFS Shares /usr/sbin/exportfs -o ro,no_root_squash 10.6.10.0/23:/media/posix/emailresources/software/gw8/software.sp1 /usr/sbin/exportfs -o ro,no_root_squash 10.6.10.0/23:/media/posix/emailresources/software/gw8/software.sp2 Exports the desired file systems via NFS. • Compose scripts similar to the one below to un-export the SDD(s) #! /bin/bash # Unload NFS Shares /usr/sbin/exportfs -uaf # Disable NFS Shares /etc/init.d/nfsserver stop /etc/init.d/portmap stop Removes all active NFS exports on the server These scripts assume that the portmap and NFS Server services are disabled on the server. Adapt the scripts for your server ans services environment. • Name these scripts something like... nfs-load.sh nfs-unload.sh ... and place then on the storage accessible to the cluster resource and modify the cluster load and unload scripts to call them. • Now compose scripts similar to the following to mount and unmount the exported NFS shares to any non-clustered servers for software installation #!/bin/bash directory="/media/software" if [ -d$directory ]; then
echo
echo GroupWise SDD mount point exists, proceeding to NFS mount
echo
/etc/init.d/portmap start
echo
mount -t nfs -o rsize=8192,tcp emailresources:/media/posix/emailresources/linux-share/software /gw8/
software.sp2 /media/software
echo The GroupWise 8 SP2 software is available at /media/software
echo Please use the unmount-gw.sh script when complete to deactivate NFS share
echo
else
echo
echo GroupWise SDD mount point does not exist
echo Creating mount point...
mkdir /media/software
echo Proceeding to NFS mount
echo
/etc/init.d/portmap start
echo
mount -t nfs -o rsize=8192,tcp emailresources:/media/posix/emailresources/linux-share/software
/gw8/software.sp2 /media/software
echo The GroupWise 8 SP2 software is available at /media/software
echo Please use the unmount-gw.sh script when complete to deactivate NFS share
echo
echo
fi
The above script checks for the /media/software mount point and creates it if it doesn't exist. It then mounts the specified SDD over NFS to that directory.
This is also why it's useful to put an "ID" file in the SDD to identify the software version using the text interfaces :) .
umount /media/software
/etc/init.d/portmap stop
echo
echo The GroupWise Software Distribution Directory
echo has been successfully unmounted
echo
The above script unmounts the imported NFS share. Understand that these are very simple scripts with almost no error control or management.
• Name these scripts something like...
gw8-sp2-install.sh
gw-unmount.sh
... and place them "/usr/sbin" and have it's permissions changed directory of the target GroupWise server and configured so only the root user can run them.
• Create as many scripts as needed for software versions and distribute them to the necessary servers
Setting up a GroupWise micro-SDD
It's important that the GroupWise POA have access to its configured SDD in order to retrieve the SOFTWARE.INF file for the GroupWise client.
When a GroupWise client detects that the bump number for the user's post office is different then the bump number in the Windows Registry, it tries to access the software.inf file, and a setup executable such as the setup.exe in the <SDD>\CLIENT\WIN32 folder.
If the GroupWise client determines that it does not have the access or a drive letter mapping to the SDD assigned to the post office, it asks the POA to help the client retrieve the software.inf file so it can determine the software version in the SDD.
When the POA delivers the software.inf file to the client:
• It looks at the "BuildNumber=" value in the file and compares it to the BuildNumber key value within the Windows registry. If the BuildNumber in the file is greater than the BuildNumber in the registry, the GroupWise client requests that the POA retrieve the setup.cfg from the <SDD>\CLIENT\WIN32 directory.
• The setup.cfg file is read and if the IP based update is enabled it transfers the gwipupdt.dll, gwupdten.dll (for English), setupip.exe, and setup.ini files to the GroupWise client over port 1677. The successful delivery of these files to the client allows the client update to initiate.
This dictates the minimum files to implement a valid SDD for client updates. If there are additional language library files required they should be added as well. If the SetupIP.exe application is configured to pull the actual client installation files from other sources over HTTP these files do not need to be present within the SDD.
File system layout:
POA SDD
• ../client
• /win32
• setup.cfg
• setup.ini
• setupip.exe
• software.inf
• gwipupdt.dll
• gwupdten.dll
Web Server Directory
• ../gwclient
• /win32
• setup.cfg
• setupip.fil
• setupip.en
With this minimum file footprint the SDD can be configured within the system and fully participate in GroupWise client auto-update for Windows clients.
Creating a Domain
There are times when you need to create a secondary Domain and it can be difficult to talk to the server at the final destination. This might be because the final destination is yet to exist, the WAN link is poor, it is still being built, whatever. In the Linux world a more common problem is that you have created a pure SLES server in the DMZ and there is no way that ConsoleOne can talk to that server - no NCP, no Samba or to use the vernacular - No Nuthin. The way to resolve this is to make use an old IT quote - "If at first you don't succeed, Cheat!"
When you create a new Domain, you have to specify a path to where that Domain will reside. What the creation wizard doesn't say is that the path specified has to be the final resting place...
Open ConsoleOne and connect to the Primary
Create the new Domain and follow through the Wizard. Use a local path
(C:\temp or /mnt/temp)
Remain connected to the primary and change the new Domains properties to the correct final path
(UNC or Linux)
Rebuild the new Secondary Domain - When prompted for the path, change to C:\temp
Copy the Domain, DC files etc. to the final resting place (File copy, USB stick)
On the SLES server in the DMZ you can start the MTA and then create what ever gateways you require, the communication between the secondary domains will deal with any later updates, changes or synchronisation.
Rebuilding Databases
When rebuilding a Domain or a Post Office you are prompted with a dialogue box for the destination path - never use that path, always rebuild to a local path. (See Top Down Rebuild below for more details)
How to do a Top Down Rebuild
This procedure is usually recommended whenever a GroupWise system is experiencing domain or post office database issues or a GroupWise system server is experiencing frequent abends or some other system critical failure in which there is a potential of compromising the integrity of your GW data.
The GroupWise system Top Down Rebuild is also recommended for periodical maintenance and before any upgrades, i.e. version or major patching implementation.
NOTE: Before proceeding, make sure that you have a current backup of the entire GroupWise system.
The Top Down Rebuild process requires the use of ConsoleOne with the GroupWise 8 snapins installed. Always use the latest version of the snapins for the version of GroupWise installed
The Stand-alone version of GWCheck for GW may also be needed to complete this procedure. For most GroupWise 8 systems, GWCheck is located in your patched Software Distribution Directory under the ..\ADMIN\UTILITY\GWCHECK folder.
When performing a top down rebuild, do it in the following manner, all steps below are done under GroupWise System in ConsoleOne...
1. Stop the Primary Domain. Copy the existing WPDomain.db to a safe location.
2. Restart the Primary Domain
3. Open ConsoleOne and Connect to your Primary Domain
• Leaving all agents up and running, right mouse click each Secondary Domain under GroupWise System view
Select GroupWise Utilities
System Maintenance
Sync Primary with Secondary
Run
OK to the path given in the Database Path dialogue.
• Do this on each Secondary Domain before rebuilding the Primary Domain.
Note: If the following error is displayed: "Error: Access denied. Caller is not allowed access to a file", unload any GroupWise Gateways that are accessing the secondary domain database file (GWIA, WebAccess, API, etc.). and ensure that there are no Administrators with ConsoleOne locking the databases.
Note: If the remote path is unavailable - Cheat! Copy the remote secondary Domain's wpdomain.db file to a local directory, add the DC files. Then re-run the Sync Primary with Secondary but change the path to this local copy when prompted for the path.
4. Rebuild the Primary Domain
Right click the Primary Domain object and select GroupWise Utilities
System Maintenance
Rebuild Database
Run
• Then on the Database Path dialogue in the Path to Database field, change the path to C:\temp, and click OK (Note: This path must exist). This will create a new domain database in [file:///C:/temp C:\temp].
Note: do not use the path as presented as this will not allow for a backup (un-rebuilt) copy of the Domain
• When the rebuild has completed, close out of ConsoleOne and shut down all the GW agents, i.e. MTA and POA for this domain, as well as any gateways you may have running within the primary domain <shudder>.
Note: Closing ConsoleOne is only necessary after rebuilding the Primary Domain because you are connected to that domain and that connection holds the wpdomain.db open, preventing the renaming of the file.
• In the domain dir. rename wpdomain.db to wpdomain.db.xx-xx-xx where xx-xx-xx is day, month and year
• "MOVE" not "COPY" up the new wpdomain.db from your c;\temp, this will remove the new wpdomain.db from your hard drive so you do not accidentally copy it up to another domain location.
• Then rename the queue directories, wpcsin to wpcsin.old, wpcsout to wpcsout.old and mslocal to mslocal.old. In the event that there have been a significant number of admin messages that have failed to process in the past, clearing these queues will ensure that there is nothing that will be applied “after the factâ€
• Bring up just the MTA and reload ConsoleOne. (To ensure that only the domain is running until the rebuild is complete)
5. Stay connected to the Primary Domain and we then start rebuilding all Secondary Domains. Repeat the steps above for for any Secondary Domains in your system.
Rebuild Secondary Domain to [file:///C:/Temp C:\Temp]
Stop Secondary Domain
Rename existing WPDomain.db to wpdomain.db.xx-xx-xx
Move new WPDomain.db to server
Rename wpcsin, wpcsout and mslocal
Start Secondary Domain
6. After each secondary domain has been rebuilt, it is then possible to rebuild the dependant post offices.
• The rebuild steps are much the same as for Post Offices as they were for your Domains, except you will need to be connected to the owning domain when rebuilding a Post Office database (As opposed to the Primary). You may also wish to rebuild any PO's in your Primary Domain before continuing on to rebuild all Secondary Domains. It is possible to rebuild a post office to C:\temp while the Post Office is running, however no other admin changes should happen at this point in time, and the Post Office will need to be stopped to replace the WPHost.db
7. Rebuild Post-Office while connected to the owning domain
Right click the Post-Office object and choose GroupWise Utilities
System Maintenance
Rebuild Database
Run
• Then on the Database Path dialogue in the Path to Database field, change the path to C:\temp, and click OK.
Stop the POA
• When complete go to your PO dir. and rename wphost.db to wphost.old and "MOVE" not "COPY" the new one from your "C" drive, this will remove the new wphost.db off your hard drive so you won't accidentally copy it up to another post-office.
• Rename the queue directories, wpcsin to wpcsin.old, wpcsout to wpcsout.old. This is to be 100% certain that there are no administrative messages in the queues that will be processed when the Post Office restarts.
• Bring up your POA agents check that there are no error messages.
8. After a TDR is is advisable to run a contents check on the data and to review the necessity of Quickfinder Index Rebuild. If these jobs are scheduled as “Scheduled Events†then these will complete in the usual time frame.
Never, Ever, under any circumstances ermm forget to check your references :-)
Single Domain Systems
It is quite possible to set up a complete (small) GroupWise system using just a single GroupWise Domain. Don't... You lose your one and only Domain you are up the creek, sans paddle! Like eDirectory and AD, GroupWise Domains are replicas, thus if you have a secondary Domain you can rebuild. You have been Warned!
Moving users when connected to the source domain
Simply put don't do this as it is just plain incorrect. Always initiate user moves from the destination domain after connecting to it.
If you do initiate a move while connected to any other Domain, including the primary, you add an additional layer to the complexity and increase the likelihood of failure .... really.
When adding a new domain do not forget to configure its links. The default link configuration for new domains is an indirect link to all other domains via the primary. If this was not your intention then .....
Always connect to the primary domain when modifying a domain's link configuration. After all it does know how to connect, and therefore direct admin traffic, to all other domains. Once connected to the primary modify the links from the target domain's perspective. This way all changes can be made in one screen.
Additionally, only change and save either incoming or outgoing links at a time. Changing and saving them both simultaneously could lead to issues with your inter-domain traffic. You could lose some hair, nails, and skin getting it all sorted.
DBCopy
DBcopy is a great tool for migration there are a couple of bad habits to avoid and a couple of others that would qualify as Good...
BAD - If you run DBcopy with the /s and /o (-s -o on Linux) then you will NOT copy any blobs over - shame really as this is a second pass
BAD - Running any DBCopy with the /l switch (-l on Linux) where you have a source and destination specified - This will do a MOVE and not a copy and thus it will ensure that you will have a bad day
POOR - When migrating from NetWare to a SLES or OES2 server, there is the option to use NCPMOUNT to mount the original NetWare volume on the SLES/OES2 server and then run DBCopy on the new server. You can grow old waiting for this to complete.
UPDATE: The above statement is true IF you do not specify to use tcp on the ncpmount command. Do this with -o tcp and watch the blobs fly.
BETTER - Far better (if you can) to use a Windows Workstation to do the DBCopy with mapped drives for the source and destination - far, far faster! NCPMOUNT is notoriously slow...
NOTE: With OES2 SP2, you have the benefit of using the embedded Novell Client (ncl)- this will simplify operations and improve the speed immeasurably!
Using legacy or incorrect snapin versions
Allowing administrators to administer GroupWise systems with legacy components can lead to a very bad result. Minimally the result may be not being able to make a configuration change because the legacy snapins do not understand updated agent or system features. At worst the creation of incorrect agent databases respective of version or even the corruption of existing databases could occur.
All domains within your system should utilize the lockout feature for administrative snapins to prevent the use of legacy or unwanted management snapins against your system.
Not Disabling QuickFinder during scheduled maintenance
Ever started a top down rebuild during the evening just to have QuickFinder maintenance kick in for the entire system in the middle of the effort? It's an annoyance best avoided so remember to turn it, and other automated maintenance, off during large scheduled maintenance windows.
Just remember to turn it back on when done :) | {"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": 0.18481393158435822, "perplexity": 6019.4423242476805}, "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-2015-40/segments/1443737946509.72/warc/CC-MAIN-20151001221906-00159-ip-10-137-6-227.ec2.internal.warc.gz"} |
http://www.oalib.com/search?kw=%20Thomas%20Ostermann&searchField=authors | Home OALib Journal OALib PrePrints Submit Ranking News My Lib FAQ About Us Follow Us+
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ISSN: 2333-9721
APC: Only $99 Submit 2019 ( 40 ) 2018 ( 63 ) 2017 ( 60 ) 2016 ( 83 ) Search Results: 1 - 10 of 31098 matches for " Thomas Ostermann " All listed articles are free for downloading (OA Articles) Page 1 /31098 Display every page 5 10 20 Item BMC Health Services Research , 2010, DOI: 10.1186/1472-6963-10-291 Abstract: The following databases were used to find articles on home-based music therapy: AMED, CAIRSS, EMBASE, MEDLINE, PsychINFO, and PSYNDEX. The search terms were "home-based music therapy" and "mobile music therapy". Included articles were analyzed with respect to participants as well as conditions and settings of HBMT. Furthermore, the date of publication, main outcomes, and the design and quality of the studies were investigated.A total of 20 international publications, 11 clinical studies and nine reports from practice, mainly from the United States (n = 8), were finally included in the qualitative synthesis. Six studies had a randomized controlled design and included a total of 507 patients. The vast majority of clients of HBMT are elderly patients living at home and people who need hospice and palliative care. Although settings were heterogeneous, music listening programs played a predominant role with the aim to reduce symptoms like depression and pain, or to improve quality of life and the relationship between patients and caregivers as primary endpoints.We were able to show that HBMT is an innovative service for future healthcare delivery. It fits with the changing healthcare system and its conditions but also meets the therapeutic needs of the increasing number of elderly and severely impaired people. Apart from music therapists, patients and their families HBMT is also interesting as a blueprint for home based care for other groups of caregivers.The use of music as a therapeutic option to support health dates back to ancient times. According to Bailey [1] some of the earliest notable mentions in Western history are found in the writings of ancient Greek philosophers Aristotle and Plato. In contemporary history, Michigan State University offered the first music therapy degree program worldwide in 1944. From that point, music therapy has established itself as a growing health profession for inpatients treatment of psychiatric diseases like schizophrenia or schizo Physics , 2012, DOI: 10.1103/PhysRevD.86.023520 Abstract: In this first paper we present a Lagrangian framework for the description of structure formation in general relativity, restricting attention to irrotational dust matter. As an application we present a self-contained derivation of a general-relativistic analogue of Zel'dovich's approximation for the description of structure formation in cosmology, and compare it with previous suggestions in the literature. This approximation is then investigated: paraphrasing the derivation in the Newtonian framework we provide general-relativistic analogues of the basic system of equations for a single dynamical field variable and recall the first-order perturbation solution of these equations. We then define a general-relativistic analogue of Zel'dovich's approximation and investigate its implications by functionally evaluating relevant variables, and we address the singularity problem. We so obtain a possibly powerful model that, although constructed through extrapolation of a perturbative solution, can be used to put into practice nonperturbatively, e.g. problems of structure formation, backreaction problems, nonlinear properties of gravitational radiation, and light-propagation in realistic inhomogeneous universe models. With this model we also provide the key-building blocks for initializing a fully relativistic numerical simulation. Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/219402 Abstract: Objectives. The aim of this meta-analysis was to determine the effectiveness of the fermented plant extract Iscador, produced from the white-berry European mistletoe, in the treatment of patients with cancer with respect to quality-of-life- (QoL-) associated measures. Methods. We searched databases such as PubMed/Medline, Excerpta Medica Database (EMBASE), CAMbase, and other for controlled clinical studies on parameters associated with QoL. Outcome data were extracted and converted into standardized mean differences and their standard errors. Results. Thirteen prospective and controlled studies which met the inclusion/exclusion criteria reported positive effects in favor of the Iscador application. A random-effect meta-analysis estimated the overall treatment effect at standardized mean difference =0.56 (CI: 0.41 to 0.71, <.0001). However, the methodological quality of the studies was poor. Conclusions. The analyzed studies give some evidence that Iscador treatment might have beneficial short-time effects on QoL-associated dimensions and psychosomatic self-regulation. BMC Cancer , 2009, DOI: 10.1186/1471-2407-9-451 Abstract: We searched several databases such as Cochrane, EMBASE, NCCAM, NLM, DIMDI, CAMbase, and Medline. Inclusion criteria were controlled clinical studies on parameters associated with survival in cancer patients treated with Iscador. Outcome data were extracted as they were given in the publication, and expressed as hazard ratios (HR), their logarithm, and the respective standard errors using standard formulas.We found 49 publications on the clinical effects of Iscador usage on survival of cancer patients which met our criteria. Among them, 41 studies and strata provided enough data to extract hazard ratios (HR) and their standard errors (Iscador versus no extra treatment). The majority of studies reported positive effects in favour of the Iscador application. Heterogeneity of study results was moderate (I2 = 38.3%, p < 0.0001). The funnel plots were considerably skewed, indicating a publication bias, a notion which is corroborated by statistical means (AC = -1.3, CI: -1.9 to -0.6, p <= 0.0001). A random effect meta-analysis estimated the overall hazard ratio at HR = 0.59 (CI: 0.53 to 0.66, p < 0.0001). Randomized studies showed less effects than non-randomized studies (ratio of HRs: 1.24, CI: 0.79 to 1.92, p = 0.35), and matched-pair studies gave significantly better results than others (ratio of HRs: 0.33; CI: 0.17 to 0.65, p = 0.0012).Pooled analysis of clinical studies suggests that adjuvant treatment of cancer patients with the mistletoe extract Iscador is associated with a better survival. Despite obvious limitations, and strong hints for a publication bias which limits the evidence found in this meta-analysis, one can not ignore the fact that studies with positive effects of VA-E on survival of cancer patients are accumulating. Future studies evaluating the effects of Iscador should focus on a transparent design and description of endpoints in order to provide greater insight into a treatment often being depreciated as ineffective, but highly valued by cancer pati BMC Complementary and Alternative Medicine , 2010, DOI: 10.1186/1472-6882-10-10 Abstract: Seventy seven staff members and 44 patients' relatives were asked to complete a survey that included the Work Environment Scale (WES-10), a Life Satisfaction Scale (BMLSS), the Conviction of Therapeutic Competency (CTC) scale and the Client Satisfaction Questionnaire (CSQ-8). To evaluate the outcome of the team building process, we analyzed changes over time in the WES-10 subscales. Additionally the interrelationship between the WES-10 subscales with other subscales and with sociodemographic parameters like age, gender was calculated by means of a bivariate correlation analysis.The team building process had a significant positive effect on perceived work environment in only one area. There was a significant improvement in the ward staffs' perception of their ability to constructively resolve conflicts 3 years after inception of the team building process than there was before inception. However, even in a unit that utilized holistic treatment and nursing in the care of severely disable patients, such care necessitating a very heavy workload, the measurements on the Self Realization, Life Satisfaction and Conviction of Therapeutic Competency scales remained high and unchanged over the three year time period of the study.Strategic interventions might be an option to improve interpersonal relationships and finally quality of patient care.The nature of the environment in which a medical staff does their work plays an important role in job satisfaction and performance. Several studies already investigated the relationship between the milieu in which health professionals work and the impact on job satisfaction. They proved that poor work environment is associated with reduced job satisfaction, absenteeism, somatic complaints, burnout and depression [1-3]. Moreover, poor work environment might also influence the work performance negatively, and might also promote negative and cynical attitudes towards patients and colleagues [4], which in turns will have an impact on the pa BMC Complementary and Alternative Medicine , 2010, DOI: 10.1186/1472-6882-10-39 Abstract: A total of 18 children aged 3.5 to 6 years with delayed speech development took part in this observational study in which music therapy and no treatment were compared to demonstrate effectiveness. Individual music therapy was provided on an outpatient basis. An ABAB reversal design with alternations between music therapy and no treatment with an interval of approximately eight weeks between the blocks was chosen. Before and after each study period, a speech development test, a non-verbal intelligence test for children, and music therapy assessment scales were used to evaluate the speech development of the children.Compared to the baseline, we found a positive development in the study group after receiving music therapy. Both phonological capacity and the children's understanding of speech increased under treatment, as well as their cognitive structures, action patterns, and level of intelligence. Throughout the study period, developmental age converged with their biological age. Ratings according to the Nordoff-Robbins scales showed clinically significant changes in the children, namely in the areas of client-therapist relationship and communication.This study suggests that music therapy may have a measurable effect on the speech development of children through the treatment's interactions with fundamental aspects of speech development, including the ability to form and maintain relationships and prosodic abilities. Thus, music therapy may provide a basic and supportive therapy for children with delayed speech development. Further studies should be conducted to investigate the mechanisms of these interactions in greater depth.The trial is registered in the German clinical trials register; Trial-No.: DRKS00000343Music therapy is an established form of creative art therapy. By using music as a specific medium of communication and expression and adapting it to the individual resources and abilities of the patient, music therapy can be beneficial in activating and suppo GMS Zeitschrift für Medizinische Ausbildung , 2007, Abstract: [english] Aims: Changes within the German Higher Education Framework act increasingly attract notice to the fact that the debate on different methods of selecting students lies in the responsibility of german medical schools. For more than 20 years the University of Witten/Herdecke has adhered to its own concept and procedure relating to its choice of students. Since 2005 this application procedure consists of a written and an oral application phase (assessment center). Within this study a retrospective classification of all applicants in the year 2005 was conducted, with the objective of finding academic and non-academic predictors for acceptance at Witten/Herdecke. Methods: All 172 applicants of the assessment center received a questionnaire asking for: age, gender, high school graduation mark, type of school, main school subjects, intended career, attendance at open house, parent graduation and profession. All duly completed questionnaires were classified according to the QUEST model from the viewpoint of acceptance versus refusal to medical studies at Witten/Herdecke. Outcomes: The QUEST model classifies the items of the questionnaire in sequence of declining power and in coherence to the targeted variable (acceptance). Affiliated with an increased probability of acceptance were: high school mark = 1.3, Steiner and Montessori schools, absence at open house, intended career as researcher and natural/social sciences and languages as main school subjects. Predictor sensitivity was 0.53, specificity reached 0.92. The positive predictive value accounted for 0.77, whereas the negative predictive value was 0.83. Conclusions: The high school graduation mark shows to be of high significance for the admission process at the University of Witten/Herdecke. Furthermore factors such as type of school, intended career and main school subjects play a major role. The high negative predictive value points out that the QUEST analysis is not suitable for replacing the existing admission process, but might be used for pre-selecting candidates. Further studies have to show whether the found effects are specific to the investigated group (applicants 2005) or whether they can be seen as representative for other cohorts of applicants at Witten/Herdecke. [german] Zielsetzung: Die Auseinandersetzung mit unterschiedlichen Verfahren der Studierendenauswahl rückt durch die Novellierung des Hochschulrahmengesetzes zunehmend in den Verantwortungsbereich deutscher Fakult ten. Als private Universit t führt die Universit t Witten/Herdecke (UWH) seit 20 Jahren universit tseigene Auswah GMS Zeitschrift für Medizinische Ausbildung , 2005, Abstract: Background: The University of Witten/Herdecke was founded in 1983 as the first private university in Germany to teach medicine. The University is not part of the centralized state system of medical placement distribution but rather has its own concept and procedure relating to its choice of students. In order to evaluate reliability and validity of the process of selecting medical students at the University of Witten/Herdecke, the first step was to analyse the interview selection process.Material and methods: The basic foundation of this examination were the results of the interview period of of the admission process from 1999 to 2000. In order to test inter-rater-reliability of the interviewers, a modified Cohen Kappa coefficient for multiple nominal scaled variables was used with regards to the group as a whole and also individually for the subgroups gender, admission year, age-groups and A Level results.Results: With Kappa-values ranging from 0.70 in 2000 to 0.88 in 1999 the reliability of the interviewer-process is obvious. However there are clear differences in the two years examined with regards to agreement in the decisions of interviewers. In the subgroup analysis with regards to gender no differences in the Kappa values were seen (male: 0,81; female: 0.8). Slightly less agreement can be seen with regards to subgroup analyses of A Level results of applicants ranging from 0.76 to 0.82.Discussion: In summary, this study shows that the application selection procedure for medicine at the medical faculty of the University of Witten/Herdecke is a reliable instrument with a high inter-rater reliability. This remains the case even though the interviewers do not seem to have standardized decision making criteria. Whether individual criteria/constellations were decisive with regards to the decision making process will be the subject of a further study. Physics , 2013, DOI: 10.1093/mnras/stu1118 Abstract: As deeper galaxy catalogues are soon to come, it becomes even more importantto measure large-scale fluctuations in the catalogues with robust statistics that cover all moments of the galaxy distribution.In this paper we reinforce a direct analysis of galaxy data by employing the Germ-Grain method to calculate thefamily of Minkowski Functionals. We introduce a new code, suitable for the analysis of large data sets without smoothingand without the construction of excursion sets. We provide new tools to measure correlation properties, putting emphasis onexplicitly isolating non-Gaussian correlations with the help of integral-geometric relations. As a first application we present the analysis of large-scale fluctuations in the luminous red galaxy sample of Sloan Digital Sky Survey data release 7 data. We findsignificant deviations from the$\Lambda$cold dark matter mock catalogues on samples as large as$500h^{-1}$Mpc (more than$3\sigma$)and slight deviations of around$2\sigma$on$700h^{-1}\$Mpc, and we investigate possible sources of these deviations.
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/124703 Abstract: Background. Researchers aimed at systematically reviewing and meta-analyzing the effectiveness of yoga interventions for fatigue. Methods. PubMed/Medline was searched until January 2012 for controlled clinical studies. Two reviewers independently extracted the data. The methodological quality of the studies was assessed. A meta-analysis was performed. Results. Nineteen clinical studies (total =948) were included in this review. Investigated yoga styles included Hatha, Iyengar, Asanas, Patanjali, Sahaja, and Tibetan yoga. Participants were suffering from cancer, multiple sclerosis, dialysis, chronic pancreatitis, fibromyalgia, asthma, or were healthy. Yoga had a small positive effect on fatigue (SMD = 0.27, 59% CI = 0.23–0.31). Seven studies received 4 points on the Jadad score. There were baseline differences in at least 5 studies. Conclusion. Overall, the effects of yoga interventions on fatigue were only small, particularly in cancer patients. Although yoga is generally a safe therapeutic intervention and effective to attenuate other health-related symptoms, this meta-analysis was not able to define the powerful effect of yoga on patients suffering from fatigue. Treatment effects of yoga could be improved in well-designed future studies. According to the GRADE recommendations assessing the overall quality of evidence, there is a moderate effect of the confidence placed in the estimates of the effects discussed here.
Page 1 /31098 Display every page 5 10 20 Item | {"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": 0.5115228891372681, "perplexity": 15734.334999408029}, "config": {"markdown_headings": false, "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-2019-35/segments/1566027323221.23/warc/CC-MAIN-20190825062944-20190825084944-00305.warc.gz"} |
http://credo.ttk.mta.hu/?q=node/107 | Electrically tunable color of mixtures of bent-core and rod-shaped molecules
, Electrically tunable color of mixtures of bent-core and rod-shaped molecules, Advanced MaterialsAdvanced Materials, vol. 20, no. 16, pp. 3138-3142, 2008. | {"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": 0.898701548576355, "perplexity": 15087.21078395166}, "config": {"markdown_headings": false, "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-2019-47/segments/1573496664808.68/warc/CC-MAIN-20191112074214-20191112102214-00329.warc.gz"} |
https://stat552.cwick.co.nz/lecture/20-transformations/ | # TransformationsFeb 25 2019
## Transforming the response
Motivation: generally we are hunting for a transformation that makes the relationship simpler.
We might believe the relationship with the explanatories is linear only after a transformation of the response, $\E{g(Y)} = X\beta$ we might also hope on this transformed scale $\Var{g(Y)} = \sigma^2 I$ What is a good $$g$$?
## Transforming the predictor
Motivation: we acknowledge that straight lines might not be appropriate and want to estimate something more flexible.
For example, we believe the model is something like $Y = f_1(X_1) + f_2(X_2) + \ldots + f_p(X_p) + \epsilon$ or even, $Y = f(X_1, X_2, \ldots, X_p) + \epsilon$
We are generally interested in estimating $$f$$.
# Transforming the response
## Transforming the response
In general, transformations make interpretation harder.
We usually want to make statements about the response (not the transformed) response.
Predicted values are easily back-transformed, as well as the endpoints of confidence intervals.
Parameters often do not have nice interpretations on the backtransformed scale.
## Special case: Log transformed response
Our fitted model on the transformed scale, predicts: $\hat{\log{y_i}} = \hat{\beta}_0 + \hat{\beta}_1x_{i1} + \ldots + \hat{\beta}_{p}x_{ip}$ If we backtransform, by taking exponential of both sides, $\hat{y_i} = \exp{\hat{\beta}_0}\exp{(\hat{\beta}_1x_{i1})}\ldots\exp{(\hat{\beta}_{p}x_{ip})}$
So, an increase in $$x_1$$ of one unit, will result in the predicted response being multiplied by $$exp(\beta_1)$$.
If we are willing to assume that on the transformed scale the distribution of the response is symmetric, $\text{Median}({log(Y)}) = \E{log(Y)} = \beta_0 + \beta_1 x_1 + \ldots + \beta_{p}x_p$ and back-transforming gives, $\exp(\text{Median}({log(Y)})) = \text{Median}(Y) = \exp(\beta_0)\exp(\beta_1 x_1)\ldots\exp(\beta_{p}x_p)$
So, an increase in $$x_1$$ of one unit, will result in the median response being multiplied by $$exp(\beta_1)$$.
(For monotone functions $$\text{Median}({f(Y)}) = f(\text{Median}(Y))$$,
but $$\text{E}({f(Y)}) \ne f(E(Y))$$ in general)
## Example
library(faraway)
data(case0301, package = "Sleuth3")
head(case0301, 2)
## Rainfall Treatment
## 1 1202.6 Unseeded
## 2 830.1 Unseeded
sumary(lm(log(Rainfall) ~ Treatment, data = case0301))
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) 5.13419 0.31787 16.1519 < 2e-16
## TreatmentUnseeded -1.14378 0.44953 -2.5444 0.01408
##
## n = 52, p = 2, Residual SE = 1.62082, R-Squared = 0.11
It is estimated the median rainfall for unseeded clouds is 0.32 times the median rainfall for seeded clouds.
(Assuming log rainfall is symmetric around its mean)
## Box-Cox transformations
Assume, the response is positive, and $g(Y) = X\beta + \epsilon, \quad \epsilon \sim N(0, \sigma^2 I)$ and that $$g$$ is of the form $g_{\lambda}(y) = \begin{cases} \frac{y^\lambda - 1}{\lambda} & \lambda \ne 0 \\ \log(y) & \lambda = 0 \end{cases}$
Estimate $$\lambda$$ with maximum likelihood.
For prediction, pick $$\lambda$$ as the MLE.
For explanation, pick “nice” $$\lambda$$ within 95% CI.
## Example:
library(MASS)
data(savings, package = "faraway")
lmod <- lm(sr ~ pop15 + pop75 + dpi + ddpi, data = savings)
boxcox(lmod, plotit = TRUE)
data(gala, package = "faraway")
lmod <- lm(Species ~ Area + Elevation + Nearest + Scruz + Adjacent,
data = gala)
boxcox(lmod, plotit = TRUE)
# Transforming the predictors
## Transforming the predictors
A very general approach is to let the function for each explanatory be represented by a finite set of basis functions. For example, for a single explanatory, X, $f(X) = \sum_{k = 1}^{K} \beta_k f_k(X)$ where $$f_k$$ are the known basis functions, and $$\beta_k$$ the unknown basis coefficients.
Then \begin{aligned} y_i &= f(X_i) + \epsilon_i \\ y_i &= \beta_1 f_1(X_i) + \ldots + \beta_K f_K(X_i) + \epsilon_i \\ Y &= X'\beta + \epsilon \end{aligned} where the columns of $$X'$$ are $$f_1(X)$$, $$f_2(X)$$ and we can find the $$\beta$$ with the usual least squares approach.
What are the columns in the design matrix for the model:
$y_i = \beta_1 1\{X_i < 5\} + \beta_2 1\{X_i \ge 5\} + \beta_3 X_i 1\{X_i < 5\} + \beta_4 X_i 1\{X_i \ge 5\} + \epsilon_i$
where $$X_i = i, i = 1, \ldots, 10$$?
What do the functions $$f_k(), k = 1, \ldots, 4$$ look like?
## Example: subset regression
cut <- 35
X <- with(savings, cbind(
as.numeric(pop15 < cut),
as.numeric(pop15 >= cut),
pop15 * (pop15 < cut),
pop15 * (pop15 >= cut)))
lmod <- lm(sr ~ X - 1,
data = savings)
summary(lmod)
## Broken stick regression
Broken stick:
$f_1(x) = \begin{cases} c - x & \text{if } x < c \\ 0 & \text{otherwise } \end{cases}$ $f_2(x) = \begin{cases} 0 & \text{if } x < c \\ x - c & \text{otherwise } \end{cases}$
$y_i = \beta_0 + \beta_1 f_1(X_i) + \beta_2 f_2(X_i) + \epsilon_i$
## Polynomials
• Polynomials: $f_k(x) = x^k, \quad k = 1, \ldots, K$
• Orthogonal polynomials
• Response surface, of degree $$d$$ $f_{kl}(x, z) = x^{k}z^{l}, \quad k,l \ge 0 \text{ s.t. } k + l = d$
## Cubic Splines
Knots: 0, 0, 0, 0, 0.2, 0.4, 0.6, 0.8, 1, 1, 1 and 1
## Linear splines
Knots: 0, 0, 0.2, 0.4, 0.6, 0.8, 1 and 1
## In practice splines provide a flexible fit
• Smoothing splines: have a large set of basis functions, but penalize against wiggliness
• Generalized Additive Models: simultaneously estimate
$y_i = f(x_{i1}) + g(x_{i2}) + \ldots + \epsilon_i$
## Transforming predictors with basis functions
• The parameters in these regressions no longer have nice interpretations. The best way to present the results is a plot of the estimated function for each X, (or surfaces if variables interact),
• The significance of a variable can still be assessed with an Extra Sum of Squares F-test, comparing to a model without any of the terms relating to a particular variable. | {"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": 0.9291400909423828, "perplexity": 2790.792199979704}, "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-2019-13/segments/1552912202924.93/warc/CC-MAIN-20190323181713-20190323203713-00353.warc.gz"} |
https://www.gamedev.net/forums/topic/502687-arrays-pointers-and-conversions/ | Public Group
# Arrays, pointers and conversions
This topic is 3614 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.
## Recommended Posts
I need to write a function that accepts a pointer to an array of pointers to integers. It needs to be a pointer because the function needs to change it. The suggested prototype (this is for an assignment) is: void func(int ***pointers); but I can also write it as: void func(int* (*pointers)[]); Apparently they are not the same thing. With the first prototype, if I do this:
int **arr = malloc(sizeof(int*) * 5);
func(&arr);
It works fine. If I do this:
int *arr[5];
func(&arr);
I get this warning: 'function' : 'int ***' differs in levels of indirection from 'int *(*)[8]'. If I run the program anyway, I get an access violation. If I try the second way with the 2nd prototype, I get a warning saying the array subscripts are different, but if I run it anyway it works fine. I can get rid of the warning by directly specifying the array size in the prototype, but I don't want to do that because the function should work for an array of any size. So basically my question is, what is the reason for the difference in behavior? Thanks in advance.
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Quote:
Original post by Gage64void func(int ***pointers);
This is a function which accepts a pointer to a pointer to a pointer to an integer (where every pointer can point to the beginning of an in-memory buffer instead of a single element).
Quote:
void func(int* (*pointers)[]);
This is a function which accepts a pointer to an array (of unknown size) of pointers to integers. This is different from the above, because dereferencing the argument yields an array and not a pointer.
Quote:
int *arr[5];func(&arr);
This will not work with the first version, because &arr is a pointer to an array, not a pointer to a pointer. You would need to decay the array to a pointer first:
int *arr[5];int **ptr = arr;func(&ptr);
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Quote:
Original post by ToohrVyk
Quote:
void func(int* (*pointers)[]);
... dereferencing the argument yields an array and not a pointer.
But if the first version yields a pointer, can't it just be treated like the beginning of an array?
Decaying the array to a pointer works fine without any warnings, but I don't really understand why it changes anything. Basically I'm trying to understand the behavior "behind the scenes" - I want to understand what causes the access violation.
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Quote:
Original post by Gage64Decaying the array to a pointer works fine without any warnings, but I don't really understand why it changes anything. Basically I'm trying to understand the behavior "behind the scenes" - I want to understand what causes the access violation.
The unrelying reason is that arrays are not pointers at the implementation level either. The decay-array-to-pointer involves the equivalent of the address-of operator: you don't just reinterpret the bit layout of the array as an adress, you have to actually take the address of the array's first element.
In practice, here's some assembly:
void ptr_frob(int **ptr){ // movq -8(%rbp), %rax // movq (%rax), %rax <--- this line! // movl $10, (%rax) (*ptr)[0] = 10;}void arr_frob(int (*arr)[]){ // movq -8(%rbp), %rax // movl$10, (%rax) (*arr)[0] = 10;}
In short, what gets passed to the second function is the address of the first element of the array, and what is passed to the first function is the address of the address of the first element in the array, so that there is an additional dereference in the first case. When you call the first function with an argument that is compatible with the second function, that second dereference will cause your write to hit whatever the first element of the array (interpreted as an address) pointed at.
In short, at the implementation level, a pointer-to-array is usually just the address of the first element of that array, whereas a pointer-to-pointer is the address of the address of the first element.
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https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/2384821?show=full | dc.contributor.advisor Draget, Kurt Ingar dc.contributor.advisor Taylor Nordgård, Catherine dc.contributor.author Wien, Ingrid dc.date.accessioned 2016-04-08T14:00:51Z dc.date.available 2016-04-08T14:00:51Z dc.date.created 2015-12-19 dc.date.issued 2015 dc.identifier ntnudaim:12157 dc.identifier.uri http://hdl.handle.net/11250/2384821 dc.description.abstract In this thesis, methods for studying diffusion of nanoparticles through pig small intestine mucus (PSIM) were to be studied and optimized. The nanoparticles used were different types of FluoSpheres® and also rhodamine labelled SNEDDS. The project was part of the work package 4 in the Collaboration on the Optimization of Macromolecular Pharmaceutical Access to Cellular Targets (COMPACT) project. By using the optimized methods diffusion through PSIM was observed both with and without the use of G-block together with the nanoparticles to study the effect of G-block on the diffusion. Both fluorometer and confocal microscopy was used to study the diffusion. dc.language eng dc.publisher NTNU dc.subject Bioteknologi (5 årig), Molekylærbiologi dc.title Nanoparticle Mobility in Pig Small Intestine Mucus (PSIM) - Optimization of Methods used to study Diffusion of Nanoparticles through PSIM, and the Effect of G-block dc.type Master thesis dc.source.pagenumber 146
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http://www.oalib.com/search?kw=A.%20Martinez&searchField=authors | Home OALib Journal OALib PrePrints Submit Ranking News My Lib FAQ About Us Follow Us+
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APC: Only $99 Submit 2020 ( 60 ) 2019 ( 728 ) 2018 ( 819 ) 2017 ( 760 ) Search Results: 1 - 10 of 465561 matches for " A. Martinez " All listed articles are free for downloading (OA Articles) Page 1 /465561 Display every page 5 10 20 Item Journal of Sensors , 2010, DOI: 10.1155/2010/816068 Abstract: Piezoelectric materials have commonly been used in pressure and stress sensors; however, many designs consist of thin plate structures that produce small voltage signals when they are compressed or extended under a pressure field. This study used finite element methods to design a novel piezoelectric pressure sensor with a C-shaped piezoelectric element and determine if the voltage signal obtained during hydrostatic pressure application was enhanced compared to a standard thin plate piezoelectric element. The results of this study demonstrated how small deformations of this C-shaped sensor produced a large electrical signal output. It was also shown that the location of the electrodes for this sensor needs to be carefully chosen and that the electric potential distribution varies depending on the poling of the piezoelectric element. This study indicated that the utilization of piezoelectric materials of different shapes and geometries embedded in a polymer matrix for sensing applications has several advantages over thin plate solid piezoelectric structures. 1. Introduction Pressure gauges of different design types (e.g., U-shaped tube gauges, piston gauges, aneroid gauges, Bourdon tube, or diaphragm gauge [1, 2], optical fiber sensors [3, 4], different electronic sensors) are currently used in different applications. Electronic sensors are convenient because they allow for easy, direct integration into electronic control schemes which can be easily miniaturized and have a short response time when used under dynamic conditions. Electronic pressure sensors can be designed by using different electromechanical or magnetomechanical effects. Electronic sensor types include piezoelectric [5], piezoresistive [6], capacitive, magnetic (inductive), potentiometric, resonant, and surface acoustic wave sensors. In the fields of robotics and orthotics the McKibben actuators have been utilized to mimic the behavior of biological muscles. Son and Goulbourne, 2009 [7] showed how the use of the two electrical parameters capacitance or resistance could be used to measure the large strains/pressure of the actuating device. MEMS based on piezoresistive pressure sensors have also been considered for pressure measurement applications; however they posses low sensitivity and suffer thermal drift [6, 8]. Piezoelectric pressure sensors are commonly used in sensor designs due to their high reliability and robustness, large range of measurable pressure, and low sensitivity to the electro-magnetic field. In traditional piezoelectric pressure sensor designs, the piezoelectric Revista Brasileira de Hematologia e Hemoterapia , 2007, DOI: 10.1590/S1516-84842007000100007 Abstract: over the last 10 years, great changes have occurred in the treatment of multiple myeloma (mm) due to the use of new drugs. considering the new options, it is essential to recognize clinical and biological parameters to arrive at the best therapeutic choice. more recently the new international staging system (iss) for multiple myeloma was validated which utilizes two straight forward laboratory parameters: the b2 microglobulin (b2m) and albumin levels. stage i: b2m < 3.5 mg/l and albumin level > 3.5 g/dl with a median survival of 62 months; stage ii: b2m < 3.5 and albumin < 3.5 g/dl or b2m > 3.5 to < 5.5 g/dl with a median survival of 49 months; stage iii: > 5.5 g/dl with a median survival of 29 months. the importance of cytogenetics and molecular features as prognostic factors is being recognized. deletion of chromosome 13 or 13q, the t(4:14) translocation, p53 deletion and amplification of chromosome band 1q21 are all associated with poor prognosis. Martinez G.A Lecture Notes in Engineering and Computer Science , 2007, Abstract: Jose A. Martinez Economics and Business Letters , 2012, Abstract: The aim of this research was to introduce a simple and easily computable metric to assess the performance of basketball players through non-scoring box-score statistics. This metric was called Factors Determining Production (FDP). FDP was created through separating points made from the remaining variables which may bequantitatively recorded. FDP was derived from the outcome of several games, it considers both teams’ statistics, and it reflects the final result of a game with noticeable merit. This metric provides a simple linear weight formula which, together with the points made by each player, yields a comprehensible picture of how well a worker(player) performed. FDP has been validated through different statistical procedures and it overcomes Win Score from a theoretical viewpoint, because it departs production (points) from factors facilitating production. Erik A. Martinez Physics , 1995, Abstract: The entropy of a quantum-statistical system which is classically approximated by a general stationary eternal black hole is studied by means of a microcanonical functional integral. This approach opens the possibility of including explicitly the internal degrees of freedom of a physical black hole in path integral descriptions of its thermodynamical properties. If the functional integral is interpreted as the density of states of the system, the corresponding entropy equals${cal S} = A_H/4 - A_H/4 =0$in the semiclassical approximation, where$A_H$is the area of the black hole horizon. The functional integral reflects the properties of a pure state. Erik A. Martinez Physics , 1996, DOI: 10.1103/PhysRevD.53.7062 Abstract: The features of the fundamental thermodynamical relation (expressing entropy as function of state variables) that arise from the self-gravitating character of a system are analyzed. The models studied include not only a spherically symmetric hot matter shell with constant particle number but also a black hole characterized by a general thermal equation of state. These examples illustrate the formal structure of thermodynamics developed by Callen as applied to a gravitational configuration as well as the phenomenological manner in which Einstein equations largely determine the thermodynamical equations of state. We consider in detail the thermodynamics and quasi-static collapse of a self-gravitating shell. This includes a discussion of intrinsic stability for a one-parameter family of thermal equations of state and the interpretation of the Bekenstein bound. The entropy growth associated with a collapsing sequence of equilibrium states of a shell is computed under different boundary conditions in the quasi-static approximation and compared with black hole entropy. Although explicit expressions involve empirical coefficients, these are constrained by physical conditions of thermodynamical origin. The absence of a Gibbs-Duhem relation and the associated scaling laws for self-gravitating matter systems are presented. Erik A. Martinez Physics , 1994, DOI: 10.1103/PhysRevD.50.4920 Abstract: The quasilocal energy associated with a constant stationary time slice of the Kerr spacetime is presented. The calculations are based on a recent proposal \cite{by} in which quasilocal energy is derived from the Hamiltonian of spatially bounded gravitational systems. Three different classes of boundary surfaces for the Kerr slice are considered (constant radius surfaces, round spheres, and the ergosurface). Their embeddings in both the Kerr slice and flat three-dimensional space (required as a normalization of the energy) are analyzed. The energy contained within each surface is explicitly calculated in the slow rotation regime and its properties discussed in detail. The energy is a positive, monotonically decreasing function of the boundary surface radius. It approaches the Arnowitt-Deser-Misner (ADM) mass at spatial infinity and reduces to (twice) the irreducible mass at the horizon of the Kerr black hole. The expressions possess the correct static limit and include negative contributions due to gravitational binding. The energy at the ergosurface is compared with the energies at other surfaces. Finally, the difficulties involved in an estimation of the energy in the fast rotation regime are discussed. Erik A. Martinez Physics , 1994, DOI: 10.1103/PhysRevD.51.5732 Abstract: The microcanonical functional integral for an eternal black hole system is considered. This requires computing the microcanonical action for a spatially bounded spacetime region when its two disconnected timelike boundary surfaces are located in different wedges of the Kruskal diagram. The path integral is a sum over Lorentzian geometries and is evaluated semiclassically when its boundary data are chosen such that the system is approximated by any Lorentzian, stationary eternal black hole. This approach opens the possibility of including explicitly the internal degrees of freedom of a physical black hole in path integral descriptions of its thermodynamical properties. If the functional integral is interpreted as the density of states of the system, the corresponding entropy equals${\cal S} = A_H/4 - A_H/4 = 0$in the semiclassical approximation, where$A_H$is the area of the black hole horizon. The functional integral reflects the properties of a pure state. The description of the black hole density of states in terms of the eternal black hole functional integral is also discussed. Erik A. Martinez Physics , 1996, DOI: 10.1103/PhysRevD.54.6302 Abstract: The general principles and logical structure of a thermodynamic formalism that incorporates strongly self-gravitating systems are presented. This framework generalizes and simplifies the formulation of thermodynamics developed by Callen. The definition of extensive variables, the homogeneity properties of intensive parameters, and the fundamental problem of gravitational thermodynamics are discussed in detail. In particular, extensive parameters include quasilocal quantities and are naturally incorporated into a set of basic general postulates for thermodynamics. These include additivity of entropies (Massieu functions) and the generalized second law. Fundamental equations are no longer homogeneous first-order functions of their extensive variables. It is shown that the postulates lead to a formal resolution of the fundamental problem despite non-additivity of extensive parameters and thermodynamic potentials. Therefore, all the results of (gravitational) thermodynamics are an outgrowth of these postulates. The origin and nature of the differences with ordinary thermodynamics are analyzed. Consequences of the formalism include the (spatially) inhomogeneous character of thermodynamic equilibrium states, a reformulation of the Euler equation, and the absence of a Gibbs-Duhem relation. Physics , 1996, DOI: 10.1063/1.531741 Abstract: We give through pseudodifferential operator calculus a proof that the quantum dynamics of a class of infinite harmonic crystals becomes ergodic and mixing with respect to the quantum Gibbs measure if the classical infinite dynamics is respectively ergodic and mixing with respect to the classical infinite Gibbs measure. The classical ergodicity and mixing properties are recovered as$\hbar\to 0\$, and the infinitely many particles limits of the quantum Gibbs averages are proved to be the averages over a classical infinite Gibbs measure of the symbols generating the quantum observables under Weyl quantization.
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http://mymathforum.com/algebra/42368-prove-1-sqrt-3-irrational.html | My Math Forum Prove 1+sqrt(3) is irrational
Algebra Pre-Algebra and Basic Algebra Math Forum
March 26th, 2014, 10:51 PM #1 Senior Member Joined: Oct 2013 From: Far far away Posts: 422 Thanks: 18 Prove 1+sqrt(3) is irrational Question) Prove that 1 + sqrt3 is an irrational number. Show similarly that m + n(sqrt3) is an irrational number for all rationals m and n (n not 0) In the question, sqrt3 means square root of 3. I will use the same notation everywhere in the question My attempt: We will assume (correctly) that sqrt3 is irrational Let 1 + sqrt3 = a/b implies sqrt3 = (a/b) - 1 implies sqrt3 = (a-b)/b implies sqrt3 is rational but sqrt3 is irrational Therefore by contradiction, 1 + sqrt3 is irrational Second part of question: Let m + n(sqrt3) = a/b implies n(sqrt3) = (a/b) - m implies n(sqrt3) = (a - bm)/b implies sqrt3 = (a-bm)/bn implies sqrt3 is rational but sqrt3 is irrational Therefore by contradiction, m + n(sqrt3) is irrational Are my proofs acceptable? Is there a better way to do this because after looking at similar problems, this has become rather mechanical for me. Thanks
March 26th, 2014, 11:51 PM #2 Senior Member Joined: Jun 2013 From: London, England Posts: 1,316 Thanks: 116 Re: Prove 1+sqrt(3) is irrational Those proofs are fine.
March 28th, 2014, 05:39 PM #3 Senior Member Joined: Nov 2013 Posts: 246 Thanks: 2 Ah but you can multiply any square root by another square root by just multiplying what is in the radicals. Sqrt 2 * Sqrt 50. Both of these are irrational but multiplying them gives 10, a rational number. Why? Because you multiply 2 * 50 = 100 and 100 is a perfect square.
March 28th, 2014, 09:52 PM #4
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Quote:
Originally Posted by shunya We will assume (correctly) that sqrt3 is irrational
I would prove this rather than assuming it. The best proof I know of is to suppose that m, n, p and q are integers, both $\frac{m}{n}$ and $\frac{p}{q}$ are in their lowest terms and
\begin{align*}\left(\frac{p}{q}\right)^2 &= \frac{m}{n} \\
np^2 &= mq^2\end{align*}
Now, since p and q share no factors, every factor of q^2 must divide n. In other words
\begin{align*}n &= \lambda q^2 \\
\lambda q^2 p^2 &= mq^2 \\
\lambda p^2 &= m \\
\end{align*}
But since m and n are coprime, $\lambda= 1$ and so $m= p^2, n=q^2$.
In other words, there is no rational number $\frac{m}{n}$ that is a perfect square unless both m and n are perfect squares. In particular, when n=1, an integer cannot be the square of a rational number, unless that number itself is an integer. And $\sqrt{3}$ is not an integer because $1^2 \lt 3 \lt 2^2$ so $1 \lt \sqrt{3} \lt 2$.
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# Prove that square root of plus another number is irrational
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http://mathhelpforum.com/differential-equations/137031-self-adjoint-voundary-value-problem.html | How do i show whether the following boundary value problem is self-adjoint in $L_{2}[0,1]$ or NOT?
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https://en.wikipedia.org/wiki/Filtered_back_projection | (Redirected from Filtered back projection)
Radon transform. Maps f on the (x, y)-domain into f on the (α, s)-domain.
Radon transform of the indicator function of two squares shown in the image below. Lighter regions indicate larger function values. Black indicates zero.
Original function is equal to one on the white region and zero on the dark region.
In mathematics, the Radon transform is the integral transform which takes a function f defined on the plane to a function Rf defined on the (two-dimensional) space of lines in the plane, whose value at a particular line is equal to the line integral of the function over that line. The transform was introduced in 1917 by Johann Radon,[1] who also provided a formula for the inverse transform. Radon further included formulas for the transform in three dimensions, in which the integral is taken over planes (integrating over lines is known as the X-ray transform). It was later generalized to higher-dimensional Euclidean spaces, and more broadly in the context of integral geometry. The complex analog of the Radon transform is known as the Penrose transform. The Radon transform is widely applicable to tomography, the creation of an image from the projection data associated with cross-sectional scans of an object.
## Explanation
If a function ${\displaystyle f}$ represents an unknown density, then the Radon transform represents the projection data obtained as the output of a tomographic scan. Hence the inverse of the Radon transform can be used to reconstruct the original density from the projection data, and thus it forms the mathematical underpinning for tomographic reconstruction, also known as iterative reconstruction.
The Radon transform data is often called a sinogram because the Radon transform of an off-center point source is a sinusoid. Consequently, the Radon transform of a number of small objects appears graphically as a number of blurred sine waves with different amplitudes and phases.
The Radon transform is useful in computed axial tomography (CAT scan), barcode scanners, electron microscopy of macromolecular assemblies like viruses and protein complexes, reflection seismology and in the solution of hyperbolic partial differential equations.
## Definition
Let ƒ(x) = ƒ(x,y) be a compactly supported continuous function on R2. The Radon transform, , is a function defined on the space of straight lines L in R2 by the line integral along each such line:
${\displaystyle Rf(L)=\int _{L}f(\mathbf {x} )\,|d\mathbf {x} |.}$
Concretely, the parametrization of any straight line L with respect to arc length z can always be written
${\displaystyle (x(z),y(z))={\Big (}(z\sin \alpha +s\cos \alpha ),(-z\cos \alpha +s\sin \alpha ){\Big )}\,}$
where s is the distance of L from the origin and ${\displaystyle \alpha }$ is the angle the normal vector to L makes with the x axis. It follows that the quantities (α,s) can be considered as coordinates on the space of all lines in R2, and the Radon transform can be expressed in these coordinates by
{\displaystyle {\begin{aligned}Rf(\alpha ,s)&=\int _{-\infty }^{\infty }f(x(z),y(z))\,dz\\&=\int _{-\infty }^{\infty }f{\big (}(z\sin \alpha +s\cos \alpha ),(-z\cos \alpha +s\sin \alpha ){\big )}\,dz\end{aligned}}}
More generally, in the n-dimensional Euclidean space Rn, the Radon transform of a compactly supported continuous function ƒ is a function on the space Σn of all hyperplanes in Rn. It is defined by
${\displaystyle Rf(\xi )=\int _{\xi }f(\mathbf {x} )\,d\sigma (\mathbf {x} )}$
for ξ ∈Σn, where the integral is taken with respect to the natural hypersurface measure, dσ (generalizing the |dx| term from the 2-dimensional case). Observe that any element of Σn is characterized as the solution locus of an equation
${\displaystyle \mathbf {x} \cdot \alpha =s}$
where α ∈ Sn−1 is a unit vector and s ∈ R. Thus the n-dimensional Radon transform may be rewritten as a function on Sn−1×R via
${\displaystyle Rf(\alpha ,s)=\int _{\mathbf {x} \cdot \alpha =s}f(\mathbf {x} )\,d\sigma (\mathbf {x} ).}$
It is also possible to generalize the Radon transform still further by integrating instead over k-dimensional affine subspaces of Rn. The X-ray transform is the most widely used special case of this construction, and is obtained by integrating over straight lines.
## Relationship with the Fourier transform
Computing the 2-dimensional Radon transform in terms of two Fourier transforms.
The Radon transform is closely related to the Fourier transform. We define the one variable Fourier transform here as
${\displaystyle {\hat {f}}(\omega )=\int _{-\infty }^{\infty }f(x)e^{-2\pi ix\omega }\,dx.}$
and for a function of a 2-vector ${\displaystyle \mathbf {x} =(x,y)}$,
${\displaystyle {\hat {f}}(\mathbf {w} )=\int \limits _{-\infty }^{\infty }\int \limits _{-\infty }^{\infty }f(\mathbf {x} )e^{-2\pi i\mathbf {x} \cdot \mathbf {w} }\,dx\,dy.}$
For convenience, denote ${\displaystyle {\mathcal {R}}_{\alpha }[f](s)={\mathcal {R}}[f](\alpha ,s)}$. The Fourier slice theorem then states
${\displaystyle {\widehat {{\mathcal {R}}_{\alpha }[f]}}(\sigma )={\hat {f}}(\sigma \mathbf {n} (\alpha ))}$
where
${\displaystyle \mathbf {n} (\alpha )=(\cos \alpha ,\sin \alpha ).}$
Thus the two-dimensional Fourier transform of the initial function along a line at the inclination angle ${\displaystyle \alpha }$ is the one variable Fourier transform of the Radon transform (acquired at angle ${\displaystyle \alpha }$) of that function. This fact can be used to compute both the Radon transform and its inverse.
The result can be generalized into n dimensions
${\displaystyle {\hat {f}}(r\alpha )=\int _{-\infty }^{\infty }{\mathcal {R}}f(\alpha ,s)e^{-2\pi isr}\,ds.}$
## Dual transform
The dual Radon transform is a kind of adjoint to the Radon transform. Beginning with a function g on the space Σn, the dual Radon transform is the function ${\displaystyle {\mathcal {R}}^{*}g}$ on Rn defined by
${\displaystyle {\mathcal {R}}^{*}g(x)=\int _{x\in \xi }g(\xi )\,d\mu (\xi ).}$
The integral here is taken over the set of all hyperplanes incident with the point x ∈ Rn, and the measure dμ is the unique probability measure on the set ${\displaystyle \{\xi |x\in \xi \}}$ invariant under rotations about the point x.
Concretely, for the two-dimensional Radon transform, the dual transform is given by
${\displaystyle {\mathcal {R}}^{*}g(x)={\frac {1}{2\pi }}\int _{\alpha =0}^{2\pi }g(\alpha ,\mathbf {n} (\alpha )\cdot \mathbf {x} )\,d\alpha .}$
In the context of image processing, the dual transform is commonly called backprojection[2] as it takes a function defined on each line in the plane and 'smears' or projects it back over the line to produce an image.
### Intertwining property
Let Δ denote the Laplacian on Rn:
${\displaystyle \Delta ={\frac {\partial ^{2}}{\partial x_{1}^{2}}}+\cdots +{\frac {\partial ^{2}}{\partial x_{n}^{2}}}.}$
This is a natural rotationally invariant second-order differential operator. On Σn, the "radial" second derivative
${\displaystyle Lf(\alpha ,s)\equiv {\frac {\partial ^{2}}{\partial s^{2}}}f(\alpha ,s)}$
is also rotationally invariant. The Radon transform and its dual are intertwining operators for these two differential operators in the sense that[3]
${\displaystyle {\mathcal {R}}(\Delta f)=L({\mathcal {R}}f),\quad {\mathcal {R}}^{*}(Lg)=\Delta ({\mathcal {R}}^{*}g).}$
## Reconstruction approaches
The process of reconstruction produces the image (or function ${\displaystyle f}$ in the previous section) from its projection data. Reconstruction is an inverse problem.
In the 2D case, the most commonly used analytical formula to recover ${\displaystyle f}$ from its Radon transform is the Filtered Backprojection Formula or Radon Inversion Formula:
${\displaystyle f(\mathbf {x} )=\int _{0}^{\pi }({\mathcal {R}}f(\cdot ,\theta )*h)(\left\langle \mathbf {x} ,\mathbf {n} _{\theta }\right\rangle )d\theta }$[4]
where ${\displaystyle h}$ is such that ${\displaystyle {\hat {h}}(k)=|k|}$.[5]
The convolution kernel ${\displaystyle h}$ is referred to as Ramp filter in some literature.
### Ill-posedness
Intuitively, in the filtered backprojection formula, by analogy with differentiation, for which ${\displaystyle \left({\widehat {{\frac {d}{dx}}f}}\right)\!(k)=ik{\widehat {f}}(k)}$, we see that the filter performs an operation similar to a derivative. Roughly speaking, then, the filter makes objects more singular.
A quantitive statement of the ill-posedness of Radon Inversion goes as follows:
We have ${\displaystyle {\widehat {{\mathcal {R}}^{*}{\mathcal {R}}g}}(k)={\frac {1}{||\mathbf {k} ||}}{\hat {g}}(\mathbf {k} )}$
where ${\displaystyle {\mathcal {R}}^{*}}$ is the previously defined adjoint to the Radon Transform.
Thus for ${\displaystyle g(\mathbf {x} )=e^{i\left\langle \mathbf {k} _{0},\mathbf {x} \right\rangle }}$,
${\displaystyle {\mathcal {R}}^{*}{\mathcal {R}}g={\frac {1}{||\mathbf {k_{0}} ||}}e^{i\left\langle \mathbf {k} _{0},\mathbf {x} \right\rangle }}$.
The complex exponential ${\displaystyle e^{i\left\langle \mathbf {k} _{0},\mathbf {x} \right\rangle }}$ is thus an eigenfunction of ${\displaystyle {\mathcal {R}}^{*}{\mathcal {R}}}$ with eigenvalue ${\displaystyle {\frac {1}{||\mathbf {k_{0}} ||}}}$. Thus the singular values of ${\displaystyle {\mathcal {R}}}$ are ${\displaystyle {\sqrt {\frac {1}{||\mathbf {k} ||}}}}$. Since these singular values tend to 0, ${\displaystyle {\mathcal {R}}^{-1}}$ is unbounded.[5]
### Iterative reconstruction methods
Compared with the Filtered Backprojection method, iterative reconstruction costs large computation time, limiting its practical use. However, due to the ill-posedness of Radon Inversion, the Filtered Backprojection method may be infeasible in the presence of discontinuity or noise. Iterative reconstruction methods (e.g., iterative Sparse Asymptotic Minimum Variance[6]) could provide metal artifact reduction, noise and dose reduction for the reconstructed result that attract much research interest around the world.
## Inversion formulas
Explicit and computationally efficient inversion formulas for the Radon transform and its dual are available. The Radon transform in n dimensions can be inverted by the formula[7]
${\displaystyle c_{n}f=(-\Delta )^{(n-1)/2}R^{*}Rf\,}$
where
${\displaystyle c_{n}=(4\pi )^{(n-1)/2}{\frac {\Gamma (n/2)}{\Gamma (1/2)}}.}$
and the power of the Laplacian (−Δ)(n−1)/2 is defined as a pseudodifferential operator if necessary by the Fourier transform
${\displaystyle \left[{\mathcal {F}}(-\Delta )^{(n-1)/2}\phi \right](\xi )=|2\pi \xi |^{n-1}({\mathcal {F}}\phi )(\xi ).}$
For computational purposes, the power of the Laplacian is commuted with the dual transform R* to give[8]
${\displaystyle c_{n}f={\begin{cases}R^{*}{\frac {d^{n-1}}{ds^{n-1}}}Rf&n{\rm {\ odd}}\\R^{*}H_{s}{\frac {d^{n-1}}{ds^{n-1}}}Rf&n{\rm {\ even}}\end{cases}}}$
where Hs is the Hilbert transform with respect to the s variable. In two dimensions, the operator Hsd/ds appears in image processing as a ramp filter.[9] One can prove directly from the Fourier slice theorem and change of variables for integration that for a compactly supported continuous function ƒ of two variables
${\displaystyle f={\frac {1}{2}}R^{*}H_{s}{\frac {d}{ds}}Rf.}$
Thus in an image processing context the original image ƒ can be recovered from the 'sinogram' data Rƒ by applying a ramp filter (in the ${\displaystyle s}$ variable) and then back-projecting. As the filtering step can be performed efficiently (for example using digital signal processing techniques) and the back projection step is simply an accumulation of values in the pixels of the image, this results in a highly efficient, and hence widely used, algorithm.
Explicitly, the inversion formula obtained by the latter method is[2]
${\displaystyle f(x)={\frac {1}{2}}(2\pi )^{1-n}(-1)^{(n-1)/2}\int _{S^{n-1}}{\frac {\partial ^{n-1}}{\partial s^{n-1}}}Rf(\alpha ,\alpha \cdot x)\,d\alpha }$
if n is odd, and
${\displaystyle f(x)=(2\pi )^{-n}(-1)^{n/2}\int _{-\infty }^{\infty }{\frac {1}{q}}\int _{S^{n-1}}{\frac {\partial ^{n-1}}{\partial s^{n-1}}}Rf(\alpha ,\alpha \cdot x+q)\,d\alpha \,dq}$
if n is even.
The dual transform can also be inverted by an analogous formula:
${\displaystyle c_{n}g=(-L)^{(n-1)/2}R(R^{*}g).\,}$
## Notes
1. ^
2. ^ a b
3. ^ Helgason 1984, Lemma I.2.1.
4. ^
5. ^ a b
6. ^ Abeida, Habti; Zhang, Qilin; Li, Jian; Merabtine, Nadjim (2013). "Iterative Sparse Asymptotic Minimum Variance Based Approaches for Array Processing" (PDF). IEEE Transactions on Signal Processing. IEEE. 61 (4): 933–944. doi:10.1109/tsp.2012.2231676. ISSN 1053-587X.
7. ^ Helgason 1984, Theorem I.2.13.
8. ^ Helgason 1984, Theorem I.2.16.
9. ^
10. ^ | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 50, "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": 0.9593627452850342, "perplexity": 620.2386979175221}, "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/1539583509845.17/warc/CC-MAIN-20181015205152-20181015230652-00471.warc.gz"} |
https://www.physicsforums.com/threads/momentum-help-please.189232/ | # Momentum Help Please
1. Oct 5, 2007
### splac6996
1. The problem statement, all variables and given/known data
Two people are standing on a very light board that is balanced on a fulcrum. The lighter person suddenly jumps straight up at . Just after he jumps, how fast will the heavier person be moving?
2. Relevant equations
M1*(Vf1) + M2*(Vf2) = M1(Vi1) + M2(Vi2)
3. The attempt at a solution
I tried using this equation but I did not get a likely solution I think I should include the distance that the two man are apart but I do not know what to do with that.
2. Oct 5, 2007
### learningphysics
I believe you need to use conservation of angular momentum about the pivot of the fulcrum... the torque about the pivot is 0... hence the angular momentum isn't changing... we can't use conservation of linear momentum because of the external forces like gravity and the force exerted at the pivot of the fulcrum.
3. Oct 8, 2007
### splac6996
so i know the mass of both men and the tangential velocity for one of them so from that point do I set the following equation equal to one another to solve for tangential velocity of the second man.
L(angular momentum)=m*r*v(tangential velocity)
4. Oct 8, 2007
### splac6996
Thanks i figured it out using that equation but r should be r^2 for both sides.
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https://www.computer.org/csdl/trans/tp/2003/11/i1499-abs.html | The Community for Technology Leaders
ABSTRACT
<p><b>Abstract</b>—Many vision algorithms depend on the estimation of a probability density function from observations. Kernel density estimation techniques are quite general and powerful methods for this problem, but have a significant disadvantage in that they are computationally intensive. In this paper, we explore the use of kernel density estimation with the fast Gauss transform (FGT) for problems in vision. The FGT allows the summation of a mixture of M Gaussians at N evaluation points in O(M+N) time, as opposed to O(MN) time for a naive evaluation and can be used to considerably speed up kernel density estimation. We present applications of the technique to problems from image segmentation and tracking and show that the algorithm allows application of advanced statistical techniques to solve practical vision problems in real-time with today's computers.</p>
INDEX TERMS
Statistical methods, kernel density estimation, fast Gauss transform, color modeling, tracking.
CITATION
Larry S. Davis, Ahmed Elgammal, Ramani Duraiswami, "Efficient Kernel Density Estimation Using the Fast Gauss Transform with Applications to Color Modeling and Tracking", IEEE Transactions on Pattern Analysis & Machine Intelligence, vol. 25, no. , pp. 1499-1504, November 2003, doi:10.1109/TPAMI.2003.1240123
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https://www.physicsforums.com/threads/the-impossible-problem.35080/ | # The Impossible Problem
1. ### gravenewworld
The Impossible Problem!!!!
I thought this might be a little fun, my professor gave us this problem for extra credit a while back, and he published it in some math journal with the title "The impossible problem." Can any of you guys solve it?
Let x and y be two numbers with 1 < x < y and x+y <= 100.
Suppose S is given the value x+y and P is given the value x*y.
<<1>> Mr. P.: I do not know the two numbers.
<<2>> Mr. S.: I knew that you didn't know the two numbers.
<<3>> Mr. P.: Now I know the two numbers.
<<4>> Mr. S.: Now I know the two numbers.
What are the two numbers?
PS.....Don't be cheap and look up the answers online
2. ### rayjohn01
284
I assume , but you did not say that the numbers are integers.
3. ### MathematicalPhysicist
do they both know eachother value?
975
<<2>> should reveal P's number to S.
5. ### MathematicalPhysicist
not the other way around?
it reveals S's number to P.
975
Er... Yeah.
7. ### zefram_c
259
I think I have a solution, shall I post it?
975
I think I might, as well. I'm getting 4 and 13.
9. ### Zurtex
1,123
That's the correct answer, I run a puzzles and riddles forum and this problem came up recently. Was great fun trying to solve.
I've seen the problem around, the limits change quite a bit (e.g the number is less than 50 or 100 or 7000). From what work I've done I know the top limit must be 80 or greater, I don't think there is any other stable solution so I think you can go as high as you want.
975
Guess I'll write up a quick, but not exactly complete, solution, then.
For starters, P does not know the solution straight off, therefore there are multiple factors of P. This implies that both x and y are not prime and that P is not the product of two primes.
Taking the fact that x and y are not prime further, we see that S is not the sum of two primes. This eliminates all even values for S.
We can impose another restriction on x and y by noting something about P, i.e. that P cannot be written as 2p, p prime. If such were the case, there would be two factorizations, {1,2p} and {2,p}, but since 1<x<y, the first factorization is not valid and P can then determine both x and y. This means that if x = 2, y != p.
Using this restriction, exclude all values of S that are 2 more than a prime.
The set of possible values of S is now limited to: 11,17,23,27,29,35,37,41,47,51,53,57,59,65,67,71,77,79,83,87,89,93,95,97,
i.e. that if S is one of the above numbers, P may not be able to determine x and y and statement <<2>> might be satisfied.
Let F = {f,g} be a factor pair of P and the set of all possible values of F the factorizations of P. One and only one F in this set must have a sum that is in the set of possible values of S. This condition is necessary to ensure that <<3>> is true, i.e. that once S reveals <<2>>, P can eliminate all possibilities but the correct answer. An easy way to force this is to let x = 4 and y = p. We then have F1={2,2p} and F2={4,p}. The sum of F1's elements is necessarily even and therefore not in S. The sum of F2's elements is necessarily odd and can be in S for a properly chosen p.
Start testing p's, starting from the lowest possible. p = 7 -> P = 28, F1 = {2,14}, F2 = {4,7}. Possible x,y doubles that can be guessed from S are {2,9}, {3,8}, {4,7}, {5,6} with corresponding products 18, 24, 28, and 30. Check to ensure that 28 is the only one in which <<2>> implies <<3>>.
P = 18, F1 = {2,9}, F2 = {3,6} with F1's sum being 11 and F2's being 9. We note that only F1's sum is in the set of S, which implies that <<1>> is false and in turn that <<2>> is false. Therefore p != 7.
Repeat with 11 to determine that p != 11, and finally repeat with 14 and note that it is in fact true.
Note that this solution does not prove that 4,13 is the only solution and does not give complete insight into the problem. I went off and did other things once I found 4,13, so if anybody wants to complete it, they're welcome to.
11. ### Zurtex
1,123
The problem I got was:
There are 2 integers greater than 1 and less than 80. They may or may not be equal. S knows the sum of the two numbers, and P knows their product.
S says, "I don't know what the two numbers are and it's impossible for you to know”
P says, "In that case I know what they are."
S then says, "In that case, so do I."
What are the 2 numbers?
Here is my solution if it gives a little more insight:
1. S does not know what x and y are (the two numbers), this means these statements can not be true:
x + y = 4
x + y = 5
x + y = 157
x + y = 158
2. S knows P does not know the two numbers, this means that whatever number S has it can not expressed as the sum of two numbers which P would then be able to deduce with the given information. So here are the circumstances where P would know the numbers from the given information:
a ) Either x or y is a prime greater than half the upper bound of the numbers (thought I'd spotted a mistake here but it's actually fine so carrying on). So it restricts the lowest sum which is (41 + 2) 43 to the highest sum (79 + 79) 158. Now it is possible to just look at combinations where the sum is less than 43 and greater than 5.
b ) If x and y are both prime numbers
c ) If x is a prime and y is its square, or if y is a prime and x is its square
3. Going through all the numbers one at a time you find that, 11, 17, 23, 27, 29, 35, and 37 are the numbers which S could know satisfy the above condition.
4. Given these numbers we can then work out all possible products, e.g: 17 = 5 + 12, product: 5*12 = 60. So here are all of them:
For 11:
18
24
28
30
For 17:
30
42
52
60
66
70
72
For 23:
42
60
76
90
102
112
120
126
130
132
For 27:
50
72
92
110
126
140
152
162
170
176
180
182
For 29:
54
78
100
120
138
154
168
180
190
198
204
208
210
For 35:
66
96
124
150
174
196
216
234
250
264
276
286
294
300
304
306
For 37:
70
102
132
160
186
210
232
252
270
286
300
312
322
330
336
340
342
5. P is able to work out what the two numbers are, given P has one of these numbers and knows the sum is one of: 11, 17, 23, 27, 29, 35, and 37 then P can work out given any of the products assuming they do not appear twice. So highlighted in bold are all numbers that appear more than once.
6. Finally we are given the piece of information that S is able to conclude what the two numbers are if P knows two numbers are. We know the numbers make one of the products above and is non bold, as there is only one left over solution for where the sum is 17 then we know that:
x + y = 17
xy = 52
x or y = 4
y or x = 13
If anyone needs me to explain anything further I'm happy to.
Last edited: Jul 15, 2004
12. ### Njorl
818
I read about this problem in Scientific American sometime in the early eighties. Computers were used to verify 4 and 13 as the only solutions below 1 billion. Given the increase in speed, it should probably not be difficult to find any solutions for several more orders of magnitude. I wonder if anyone has done it.
Njorl
13. ### zefram_c
259
Here's a short expansion on cookiemonster's approach:
We have found that the set of possible sums is 11,17,23,27,29,35,37,41,47,51,53,57,59,65,67,71,77 ,79,83,87,89,93,95,97 so far. But we can rule out half of these. Suppose that P=610=61*5*2. P knows that he has to group the factors into two such that their sum is under 100. He can only do that if he chooses 61 and 10. Their sum is 71. Hence if the sum was 71, it would be possible for P to resolve the numbers without any other information if his number happens to be 610. Hence we rule out 71 as a possible sum for which S can assert <<2>> We can similarly rule out all sums greater than 53, so we need consider only 11,17,23,27,29,35,37,41,47,51,53 . From here on, I programmed the computer to find the pairs as indicated; only 4 and 13 allow both <<3>> and <<4>>
14. ### e(ho0n3
Confused?
Can someone explain to me what the relevance of the conversation between P and S is? I don't understand this at all. What does it mean for either S or P to "know" the two numbers?
15. ### Gokul43201
11,046
Staff Emeritus
"Don't know" implies multiple integer solutions for the repective equations : xy = P and x+y=S.
975
S is given the number x+y. P is given the number xy.
P now wants to know all the possible values of x and y as far as he can tell. He knows that the two values x and y must multiply to yield xy, so he looks at the factors of xy. Each factor pair (excluding (1)(xy)) yields a possible x,y double, so all the factor pairs of xy are the possible values of x and y as far as P can tell.
S wants to know all the possible values of x and y as far as he can tell. He knows that the two values x and y must add to yield x+y, so he makes the equation x + y = S and solves for one of them, e.g. y = S - x. Now he starts putting in values of x to get a corresponding value for y. This is how he generates his x,y doubles.
When S says that he knew that P cannot pin down the two numbers, he's giving away information about what S is. Note that for every double P generates, he can then work up with these doubles to figure out what S would be in such a case, and S can work up from his doubles to figure out what P would be. S can only say that he knew P doesn't know what the two numbers are for only certain values of x+y. Note that some conditions necessary for these values are given in each solution.
When S says <<2>>, P looks at his possible doubles and figures out for which one can S actually say that. There must be only one possibility in order for <<3>> to be true, so this further limits x and y. And when P says <<3>>, he is saying that saw only one possible factor in which S could say that, not two or three or more, so S can look at his possibilities and see which ones allow P to say that and thereby eliminate possibilities.
17. ### e(ho0n3
I'm still confused? So can S look at P's possibilities and vice versa? Let A = {(x,y) : x + y = S} and B = {(x,y) : xy = P} with the constraints implied. I'm figuring that when S says <<2>> the number of possibilites becomes $A \cup B$ right? Why do I care what P or S say afterwards when I have the set of solutions?
18. ### fourier jr
WTF!! how in the world do you guys figure out that stuff?! I guess I could sit here for a couple hours until I can follow the whole solutions... :surprise:
975
S does not know what xy is and P does not know what x+y is. However, P can make a list of possible values of x+y that would still satisfy xy and S can make a list of possible values of xy that would still satisfy x+y. <<2>> gives information to P about x+y, which P can then use to eliminate some possibilities. <<3>> gives information to S about xy, which S can then use to eliminate possibilities.
Note that if ever P determines x+y or S determines xy, they can immediately determine the solution, as it's then a 2-variable 2-equation problem with solution
$$x = \frac{1}{2}\left( S - \sqrt{S^2 - 4P} \right) \qquad y = \frac{1}{2}\left( S + \sqrt{S^2 - 4P} \right)$$
However, before <<2>> or <<3>>, P cannot uniquely determine S and S cannot uniquely determine P, so they cannot solve the system. They can only reduce it to a few possibilities.
In your notation, let C = {(x,y) : <<2>>==TRUE}. <<3>> implies that $B \cap C$ has a single entry, which therefore uniquely determines (x,y) for P. Furthermore, let D = {(x,y) : B s.t. <<3>>==TRUE}. <<4>> implies that $A \cap D$ has a single entry as well.
20. ### e(ho0n3
So S doesn't know what P is and vice versa right? Does S know that he the sum of two numbers? Does P know he is the product of two numbers? You'll have to forgive me, as I am slow (i.e. a retard).
WHAT information is being given? S says "I knew that you didn't know the two numbers." So what? Who cares if he KNEW? Wouldn't it be better to KNOW what S knows. Suppose S and P are ignorant of their formulation. If S KNOWNS that P = xy for some x and y, then S can determine the pairs of numbers (x, y) such that P = xy. If P KNOWS that S = x + y for some x and y, the P can determine the pairs (x, y) such that S = x + y, and once both of them share this information (i.e. "Hey S, I have these pairs, what do you have?"), then they can both determine what the correct pair is (or pairs are). | {"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": 0.8695990443229675, "perplexity": 522.4318363621555}, "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-2015-40/segments/1443736680773.55/warc/CC-MAIN-20151001215800-00174-ip-10-137-6-227.ec2.internal.warc.gz"} |
https://nipype.readthedocs.io/en/latest/devel/provenance.html | # W3C PROV support¶
## Overview¶
We’re using the the W3C PROV data model to capture and represent provenance in Nipype.
For an overview see:
PROV-DM overview
Each interface writes out a provenance.json (currently prov-json) or provenance.rdf (if rdflib is available) file. The workflow engine can also write out a provenance of the workflow if instructed.
This is very much an experimental feature as we continue to refine how exactly the provenance should be stored and how such information can be used for reporting or reconstituting workflows. By default provenance writing is disabled for the 0.9 release, to enable insert the following code at the top of your script:
>>> from nipype import config
>>> config.enable_provenance() | {"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": 0.3376390337944031, "perplexity": 8381.053028082588}, "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-2020-40/segments/1600402088830.87/warc/CC-MAIN-20200929190110-20200929220110-00663.warc.gz"} |
https://www.psi.ch/swissfel/x-ray-methods-in-correlated-electron-science | X-ray methods in correlated electron science
The relevance for correlated-electron materials of ps dynamics at the nanoscale, together with strong interaction of X-ray photons with all four of the C-S-O-L degrees of freedom, promises important applications of the SwissFEL. To begin the discussion of relevant X-ray techniques, we consider the Hamiltonian describing an X-ray photon field interacting with the electrons in the sample [6, 7]. For the moment, we treat a single free electron, without spin:
where describes photons in the radiation field, with wavevector and polarization ε. Expanding the expression for H, we obtain:
The interaction Hamiltonian, Hinteraction, is responsible for producing transitions from an initial state to a final state of the combined system of X-rays and sample. According to Fermi’s Golden Rule, the transition rate is given by:
Here we are interested in “photon-in” (k) to “photon-out” (k’) transitions – thus we include only those terms which are quadratic in the vector potential A. We disregard the linear terms, which are responsible for photoemission. The transition rate is proportional to the square of the “scattering factor”, , which, in turn, is a function of the momentum and energy transfers and .
Consider now the following cases:
Hard X-ray diffraction
If the photon energy is much larger than the excitation energies En-E0 of the system, we need only consider the first matrix element in the expression for w:
where is the ground-state of the system, and where we now sum over all the electrons, with coordinates. For a crystalline sample, the scattering factor , is written
i.e., as a lattice sum over the unit cells and a “structure-factor” sum over the I atoms per unit cell. The quantity is known as the atomic scattering factor. For a perfect crystal, the lattice sum dictates that F is non-zero only if , a reciprocal lattice vector. This is the condition for Bragg scattering, which, using the relations and , can be expressed as Bragg’s law: . We thus see that diffraction at the Bragg angle θ is possible when the X-ray wavelength λ is shorter than twice the lattice-plane spacing (2d). The scattered intensity at the Bragg condition is proportional to . The sensitivity of the Bragg condition to the lattice parameters implies that the diffraction of short X-ray pulses can be used to directly observe lattice phonons.
Soft X-ray resonant diffraction
If the incoming photon energy lies close to an atomic absorption edge, it is the second-order contribution from H2 which dominates the scattering rate. The case of elastic scattering, , is treated via an energy-dependent correction to the atomic scattering factor:
where the correction term obeys:
We see that the scattering is sensitive to the electronic structure of the ground- and intermediate states and to the polarization of the incoming and outgoing photons (see Fig. V.6 a). The existence of a “core-hole” in the intermediate state is responsible for introducing the linewidth parameter Γ, representing the lifetime of the state |n>.
For soft X-rays, where the photon wave-vector k is significantly larger than the atomic dimensions, one can expand the exponentials into dipole, quadrupole and octupole terms:
The product of two such matrix elements yields a hierarchy of tensorial terms: dipole-dipole (rank 2), dipolequadrupole (rank 3), quadrupole-quadrupole (rank 4), etc. These tensorial components can be enhanced by a suitable choice of polarizations and scattering vector. In TMOs, interesting resonances are the L2 and L3 transition-metal edges, which connect filled 2p and unfilled 3d states. The corresponding photon wavelength, approximately one nm, allows the observation of resonant soft-X-ray diffraction, and the dependence of the matrix elements on valence-band electronic structure produces superstructure Bragg reflections, corresponding, for example, to orbital-ordering in the correlatedelectron material. And when circularly-polarized X-rays are used, XMCD-contrast (see Chapter I) makes magnetic order visible. Finally, a charge-dependent shift of the initial core level shifts the energy-dependent resonant scattering profile (see Fig. V.6 b), providing a chargeorder contrast. One should note that soft-X-ray resonant diffraction is not easy: it requires scanning of the incoming photon energy, a multi-axis diffractometer in vacuum, and perhaps polarization-analysis of the scattered beam. With the SwissFEL, a pump-probe resonant diffraction experiment can follow, for example, the melting of orbital order by a laser pump pulse and its recovery at later times. Its shor t pulses and flexible energy tuning, par ticularly near 1 nm wavelength, make the SwissFEL an ideal source for such investigations of TMO correlated electron materials. A par ticularly interesting application of pump-probe resonant elastic scattering at the SwissFEL would be the time-resolved study, at the nanometer scale, of so-called “orbitons”, wave-like excitations of the orbitally-ordered phase, in manganites (see Fig. V.7).
Resonant inelastic X-ray scattering (RIXS)
We now lift the restriction to elastic scattering, by allowing to be non-zero, requiring, in general, energy analysis of the scattered photons. A schematic of the RIXS process is shown in Figure V.8. The scattering rate is now given by:
Note the following features: a) The sensitivity to photon polarization and valence electronic states seen in resonant elastic scattering is also present for RIXS. b) Although there exists a (virtual) core-hole in the intermediate state, evidenced by the Γ-term in the denominator, because there is no hole in the final state, the wk’ resolution of RIXS can in principle be infinitely good – as evidenced by the energy δ-function. c) Low-energy collective excitations, such as phonons, plasmons, spinwaves, etc., of the sample are accessible with RIXS, since what is measured is the energy difference between the incoming and outgoing photons. And since two photons are involved, the dipole selection rule Δl=±1 does not apply, such that a d→d transition can be observed (see Fig. V.9 a). d) Although per formed at resonance, RIXS is a low-efficiency process: In resonant elastic scattering, the excitation of each of the N scattering atoms can be coherently added, since there is a unique final state. This results in a scattering intensity proportional to N2. For RIXS, because the vir tual excitation of different atoms leads to different final states, the contributions add incoherently, resulting in an intensity propor tional to N [7]. Performing RIXS is an extremely challenging undertaking, due to the low scattered intensity and because of the necessity of per forming an energy (and scattering-angle) analysis of the scattered radiation. For pump-probe RIXS experiments at the SwissFEL, it would therefore be par ticularly interesting to realize a single-shot mode of measuring, either in the frequency (see Infobox) or in the time (ditto) domains.
The intermediate scattering function
At the beginning of this Section, we saw how the transition rate for X-ray photon scattering, with momentum transfer and energy transfer , is related to the scattering function . This function shows peaks as a function of ω corresponding, for example, to longlived oscillations (quasipar ticles), such as phonons, spin-waves, etc. But finite lifetime effects will broaden these quasipar ticle peaks, and in the limit of strong damping, it may be advantageous to observe the timedependent fluctuations of the system directly – i.e., to measure instead the so-called time-domain or intermediate scattering function [12]:
The intermediate scattering function basically provides the correlation time (over which S(Q,t) decays to the value 1/e) for the equilibrium fluctuations of a system, as a function of the fluctuation length scale 1/Q. By monitoring the scattered intensity I(θ,t) at a par ticular scattering angle 2θ (related to the momentum-transfer by Q = 4π sinθ/λ), one has access to S(Q,t) via the intensity correlation function g2(θ,t) and the “Sieger t relation” [13]:
A measurement of I(θ,t) on the ultrafast time scale, pertinent to correlated electron materials, would require reading out a detector at an impossible rate of GHz -THz. Two realistic alternatives, however, which are well-suited to the characteristics of the SwissFEL, are provided by the “split-pulse” and “Mössbauer filter foil” techniques and are described in Infoboxes.
A single-shot RIXS spectrometer
When per forming resonant inelastic X-ray scattering (RIXS), the scattered intensity as a function of outgoing photon energy is normally acquired for par ticular settings of the incoming energy by the monochromator. This is a procedure which is incompatible with single-shot operation at the Swiss- FEL. One would like to instantaneously obtain a twodimensional plot of the scattered intensity as a function of Ein, Eout. A method of per forming single-shot RIXS has been proposed by V. Strocov [25] (see Fig. V.i2). The Swiss- FEL pulse is dispersed vertically by a monochromator (upper right in the figure) and brought to a line focus on the (homogeneous) sample. Scattered light corresponding to the various incoming photon energies is then focused to a vertical line and dispersed in Eout horizontally onto a CCD detector. The result is the desired two-dimensional plot.
RIXS in the time-domain
A principal drawback of conventional RIXS measurements is the necessity of a fine energy-analysis of the scattered radiation, resulting in a significant loss of intensity. It has been suggested [26] that the ultrashor t pulses of the SwissFEL could be used to effectively per form RIXS in the time-, instead of the energy domain. If a suitable non-linear (NL) optical medium for soft X-rays could be developed, one could imagine performing X-ray heterodyne spectroscopy: A SwissFEL pulse is split into two pulses. One of these is scattered by the sample, causing the creation, by inelastic scattering, of multiple frequency components. This multifrequency pulse is then recombined with the unscattered reference pulse in the NL-medium, where sum and difference frequencies are generated. The difference frequencies appear at the detector as slow oscillations, corresponding to the inelastic energy loss or gain in the sample. Heterodyne spectroscopy is routinely per formed with optical pulses, using the frequency-resolved optical gating (FROG) technique (see Fig. V.i3). Realization of an X-ray FROG will require the transform-limited pulses which a seeded SwissFEL will provide.
Split-pulse XPCS
X-ray photon correlation spectroscopy measures the time-correlation function of the coherently-scattered radiation intensity from a fluctuating sample:
Since this requires a detector bandwidth which exceeds that of the fluctuations, one is generally limited to times τ longer than 10 nsec. The use the SwissFEL to probe ps-dynamics will require a different approach – “split-pulse XPCS” (see Fig. V.i4) [11]. Here a single SwissFEL pulse is split and delayed, producing a pair of pulses with tunable separation τ. The 2d-detector then registers a doubleexposure speckle pattern, and the speckle contrast will decrease when τ exceeds the fluctuation correlation time τc. That one indeed can measure g(τ) with split-pulse XPCS has been demonstrated by Gutt et al. [29]: The double exposure delivers the intensity , and the speckle contrast is given by the variance:
We note that:
and that, for a fully coherent beam,
We thus obtain:
.
The Mössbauer filter-foil technique
The Mössbauer filter-foil technique provides an alternate method for measuring the intermediate scattering function [30]. Foils containing a stable Mössbauer isotope are placed in front of and behind the scattering sample and, at time t=0, a resonant Swiss- FEL pulse excites the isotope. The subsequent decay is then monitored by the total transmitted counting rate, measured in the forward direction (see Fig. V.i5). Denoting by ρ(Q,t) the spatial Fourier transform of the electron density in the sample at the time t, the intermediate scattering function is given by S(Q,t) = 〈ρ(Q,0)ρ*(Q,t)〉. Further, we let |g(t)|2 denote the decay probability of the Mössbauer isotope a time t after excitation. The signal I(t) at the detector is the square of the coherent sum of the probability amplitudes for a) radiation scattered by the sample at time zero and emitted by the nuclei of the second foil at time t and b) emitted by the first foil at time t and directly scattered into the detector:
From this expression, the intermediate scattering function can be extracted. By far the most popular Mössbauer isotope is 57Fe, with a resonant energy of 14.4 keV and an excited state lifetime of 141 ns. An upgrade option for the SwissFEL will make this photon energy accessible with the fundamental undulator radiation, as well as still higher energies using XFEL harmonics [31]. Advantages of the filter-foil method in combination with the SwissFEL are: a) extremely intense X-ray pulses with zero background during the nuclear decay, and b) measurements of S(Q,t) for times far longer than those accessible with the split-pulse XPCS method. (The maximum feasible split-pulse delay will be ns for hard X-rays and tens of ps for soft X-rays.)
Share | {"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": 0.9271823167800903, "perplexity": 1812.8926335944855}, "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-2017-39/segments/1505818689874.50/warc/CC-MAIN-20170924044206-20170924064206-00680.warc.gz"} |
http://mathhelpforum.com/pre-calculus/42757-ellipse-1-a.html | 1. ## ellipse 1
An ellipse have the centre in origin and axis lower on the OX axis. Find your equation knowing that the major axis is twice of the minor axis and the ellipse passing through point P $(\frac{\sqrt{7}}{2},3)$
$16x^2+4y^2=64$
2. Originally Posted by Apprentice123
An ellipse have the centre in origin and axis lower on the OX axis. Find your equation knowing that the major axis is twice of the minor axis and the ellipse passing through point P $(\frac{\sqrt{7}}{2},3)$
$16x^2+4y^2=64$
It took me a little bit more playing before I understood your "axis lower on the OX axis". The book answer did help.
You probably meant that the major axis is along the y-axis.
So, with a = semi-major axis and b = semi-minor axis,
(x^2)/(b^2) +(y^2)/(a^2) = 1 -----(i)
a = 2b ----given
a^2 = 4b^2
At point (sqrt(7) /2,3),
Substitutions into (i),
[(Sqrt(7) /2)^2]/(b^2) + (3^2)/(4b^2) = 1
7/(4b^2) +9/(4b^2) = 1
Clear the fractions, multiply both sides by 4b^2,
7 + 9 = 4b^2
b = 2 units --------**
And so, a = 2b = 4 units ----**
Hence, the ellipse is
(x^2)/(2^2) +(y^2)/(4^2) = 1
(x^2)/4 +(y^2)/16 = 1
Clear the fractions, multiply both sides by 16, | {"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": 4, "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": 0.5946329236030579, "perplexity": 2217.2469560875898}, "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-2016-36/segments/1471982292607.17/warc/CC-MAIN-20160823195812-00127-ip-10-153-172-175.ec2.internal.warc.gz"} |
http://blogs.mathworks.com/steve/2012/07/09/a-cody-problem-simplify-a-polygon/ | # A Cody problem: simplify a polygon7
Posted by Steve Eddins,
Today I'm combining my blog post with a new problem submission on Cody. The problem is related to the function bwboundaries in the Image Processing Toolbox. This function traces the boundaries of objects (and holes within objects), returning each boundary as a set of x-y vertices.
Here's an example from the documentation:
I = imread('rice.png');
BW = im2bw(I, graythresh(I));
[B,L] = bwboundaries(BW,'noholes');
imshow(label2rgb(L, @jet, [.5 .5 .5]))
hold on
for k = 1:length(B)
boundary = B{k};
plot(boundary(:,2), boundary(:,1), 'w', 'LineWidth', 2)
end
hold off
I have heard a few times from customers that they would like to eliminate "unnecessary vertices" in the output of bwboundaries. To illustrate, let's look at the boundary for a simple binary image containing a rectangle.
close(gcf)
bw = false(15,40);
bw(5:10,10:30) = true;
B = bwboundaries(bw);
boundary = B{1};
imshow(bw,'InitialMagnification', 'fit')
hold on
plot(boundary(:,2), boundary(:,1))
plot(boundary(:,2), boundary(:,1), '*')
hold off
Note that the boundary goes through the pixel centers, which is why a little bit of white appears outside the boundary line.
I can imagine that for some applications it would be nice to have the boundary polygon without as many vertices, like this:
x = [10 30 30 10 10];
y = [5 5 10 10 5];
imshow(bw,'InitialMagnification', 'fit')
hold on
plot(x, y)
plot(x, y, '*')
hold off
This idea has been on my potential blog topics list for a long time, and today I finally got around to thinking about it. I can think of several different approaches, and it's not immediately obvious to me which approach might be best (for whatever definition of best you believe in).
So I thought I would make a Cody problem out of it and see what creative ideas pop up.
I encourage you to give the problem a try. I'll summarize the results later.
Good luck!
UPDATE: In a week or so, I'll a pick the best solution (according to the well-known purple-seven multiphasic optimality criterion) and send out a prize (a hat or something similar) to the solver.
Get the MATLAB code
Published with MATLAB® 7.14
### Note
Steve Eddins replied on : 1 of 7
UPDATE: In a week or so, I’ll a pick the best solution (according to the well-known purple-seven multiphasic optimality criterion) and send out a prize (a hat or something similar) to the solver.
Cris Luengo replied on : 2 of 7
The problem with my solution, even though it passes the tests, is that the first point (and last, which are assumed to be equal) will never be deleted. If this point is in the middle of a straight line, the solution will be wrong. Fixing this somewhat complicates the code.
Steve Eddins replied on : 3 of 7
Cris—Thanks for pointing out a flaw in my test suite. I added a new test case and re-scored all the entries.
Sven replied on : 4 of 7
Hi Steve, nice little problem :)
Are you sure the test set at the moment is correct?
I’ve got a solution that fails only on the “Two rectangles separated by line segment” test. This test has:
P = [ …
1 2
1 1
2 1
{snip}
1 4
1 3
1 2];
According to the criteria to “remove as many vertices as possible from P”, I think that the progression from [1 4] to [1 3] to [1 2] to [1 1] can be reduced to just [1 4] to [1 1]. However, you’ve kept [1 2] in the “correct” output… *scratches head quizically*
Richard Brown replied on : 5 of 7
Hi Steve, there’s a problem in your test suite – problem 7 has a starting vertex that can be deleted, but that isn’t in your solution
i.e. P looks like this:
P = [1 2;
1 1;
\vdots
1 4;
1 3;
1 2 ];
The vertex [1 2] should be removed, but isn’t in your solution …
Steve Eddins replied on : 6 of 7
Sven, Richard—Thanks. I have updated test case #7, and the solutions are being rescored. | {"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": 0.47679227590560913, "perplexity": 1740.4833988473342}, "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-2017-09/segments/1487501170380.12/warc/CC-MAIN-20170219104610-00121-ip-10-171-10-108.ec2.internal.warc.gz"} |
https://www.lessonplanet.com/teachers/changes-in-nature-science-5th | # Changes in Nature
Fifth graders identify the chemical and physical changes in the water cycle, carbon cycle, and the effects of weathering. They analyze the periodic table, and observe how vinegar reacts with limestone in a chemical reaction that causes a physical change at the same time.
Concepts
Resource Details
5th
Subjects
Life Science
1 more...
Resource Type
Lesson Plans
Instructional Strategy
Inquiry-Based Learning
Usage Permissions
Fine Print | {"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": 0.867708683013916, "perplexity": 8167.127219949509}, "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-2017-30/segments/1500549423927.54/warc/CC-MAIN-20170722082709-20170722102709-00527.warc.gz"} |
https://www.gamedev.net/articles/programming/general-and-gameplay-programming/working-with-avi-files-r840/ | • # Working With AVI Files
General and Gameplay Programming
[email="darrennix@msn.com"]Comment on this Document[/email]
[size="5"]Abstract
You have several options when working with AVI files.
• Parse the file yourself.
• Parse the file with MMIO routines.
• Piece together a DirectShow filter.
• Use the Win32 AVIFile API.
• Use MCI to draw it to a window.There are benefits and drawbacks to each of them, but only Microsoft's AVIFile api makes it easy enough for the novice, but advanced enough for most purposes. This document deals with the loading and interpreting of AVI files using the AVIFile interface. If you are already comfortable with DirectShow, then I recommend that method instead. As an alternative, AVIFile will allow you to process the many different kinds of AVI files, handle decompression, and read the video frames easily. The API is also for reading any Resource Interchange File Format (RIFF), so learning the API will enable you to process other types of RIFF files like WAV, and even help you to create your own custom format that extends AVI's capabilities while remaining compatible with other software.
This document will show you how to extract video and sound information from an AVI file. You'll see how to synchronize game elements over the top of the AVI video, and the sample code shows how the AVI can be blitted with transparency so it's superimposed over a game's action. You will receive royalty-free wrapper classes for avi files, bitmap files, and direct draw to get you started.
[size="5"]Introduction
When learning to process a file, I usually learn its file format and create a wrapper class to make it easier for the rest of my code. One thing noticed as files get more advanced, are that they're utilizing a chunk based format. WAV is probably the easiest of the chunk based, and PCM waves can be parsed with little difficulty. The reason why I recommend using an API for AVI files, though, is because they come in so many forms that you must either learn them all or limit your capability in some way. They're also usually compressed with one of several different formats.
This document is designed to lead you through the entire process from beginning to end. I only talk about the stuff that's pertinent to opening and getting frames and audio from the file. I don't go into how the sound can be played back or the images rendered, because there are many different ways depending on what you want to do. The sample code, written using MSVC++ 6.0, displays the frame sequence using DirectX 7.0 in full screen exclusive mode. If there's popular demand I will submit other articles to describe in more detail how the video is rendered and sound played back.
[size="5"]Reference
[size="3"]
Project Settings
You'll need to link to winmm.lib, and vfw32.lib to use the AVIFile functions. They should be included in Borland as well. They're included with MSVC++ 6.0, but should also be available for versions as low as 4.0. Newer versions of the libraries are also part of the latest Platform SDK release from Microsoft.
You can use these functions with any kind of project: C, C++, MFC, Win32, console app, Direct Draw, Direct3D, etc.
[size="3"] Initialization
AviFileInit();
[size="3"] Opening the AVI File
The AVIFileOpen function only takes a string for the filename, as opposed to a file handle. This means that you'll be unable to embed an AVI file into a proprietary WAD format and load it directly from within while using this API, unless you can figure out a trick. It's possible to encode the file format and/or change the extension to protect your copyright for a game's release.
PAVIFILE pAviFile; if(AVIFileOpen(&pAviFile, "filename.avi", OF_READ, NULL)) // error
[size="3"] Getting the File's Info
AVIFILEINFO info; AVIFileInfo(pAviFile, &info, sizeof(info));
The info structure contains some extra stuff you might use later on, but nothing spectacular or essential for our purpose so I won't go into that here.
[size="3"] Finding Audio and Video Streams
An AVI file may have any number of streams of any type. Usually they're just audio and video streams. It's possible to open all of the streams and then query what type they are later. Usually a program ignores streams it doesn't recognize or need. This allows you to innovate the AVI file format, while retaining compatibility with other programs.
I'll use preallocated arrays to contain only the audio and video streams in the file. Ordinarily I would recommend a linked list, but such implementation details are out of this document's context, not to mention most AVI files will have only one audio and video stream anyway.
PAVISTREAM pAudio[MAX_AUDIO_STREAMS], pVideo[MAX_VIDEO_STREAMS]; int nNumAudioStreams=0, nNumVideoStreams=0;
The loops to open each stream are pretty strait forward. I explicitly specify what type of stream to load, either streamtypeAUDIO or streamtypeVIDEO. I ignore any other stream that might be in the file, like streamtypeTEXT or streamtypeMIDI. To load any stream type available, specify zero for the streamtype.
do { if(AVIFileGetStream(pAviFile, &pAudio[nNumAudioStreams], streamtypeAUDIO, nNumAudioStreams)) break; } while(++nNumAudioStreams < MAX_AUDIO_STREAMS); do { if(AVIFileGetStream(pAviFile, &pVideo[nNumVideoStreams], streamtypeVIDEO, nNumVideoStreams)) break; } while(++nNumVideoStreams < MAX_VIDEO_STREAMS);
Now we have neat arrays of audio and video streams, and we know the number contained in each. Processing them will consist of looping through these streams, so here forward I simply refer to the current stream as pStream. Note that we haven't actually loaded anything yet, we've merely obtained a handle to the data that's in the file. This allows us to play potentially massive AVI files without a significant memory impact.
[size="3"] Getting a Stream's Info
A stream's information is obtained simply through the use of this function.
AVISTREAMINFO info; if(AVIStreamInfo(pStream, &infoAudio, sizeof(info))) // error
Like the file's info, this stuff isn't essential for processing an AVI file. There are some things you can calculate from the structure members, but I've found an easier way to determine these values that's described later.
[size="3"] Determining a Stream's Format
Since a stream can be of numeral kinds, we need to know its format. First of all, we must know how long the format data is. The following code accomplishes that.
LONG lSize; // in bytes if(AVIStreamReadFormat(pStream, AVIStreamStart(pStream), NULL, &lSize)) // error
Audio Stream Specifics
The format data for an audio stream is based on the WAVEFORMAT structure, but it may have a few extra data members at the end and a different structure name. You can tell what structure it is by comparing the lSize variable with the sizeof(WAVEFORMATEX) or sizeof(PCMWAVEFORMAT). These structures, and most others, simply extend WAVEFORMAT with a few extra bytes.
PCMWAVEFORMAT includes the important wBitsPerSample member, and WAVEFORMATEX includes both wBitsPerSample and cbSize. The cbSize member tells how many extra bytes are stored after the WAVEFORMATEX structure. The extra bytes are for non-Pulse Code Modulation (PCM) formats, if you want to support those. Usually you'll only find PCM formats, but the code you're about to see supports all of them.
We'll accomplish that by reading in a chunk and casting it to a WAVEFORMAT pointer.
LPBYTE pChunk = new BYTE[lSize]; if(!pChunk) // allocation error if(AVIStreamReadFormat(pStream, AVIStreamStart(pStream), pChunk, &lSize)) // error LPWAVEFORMAT pWaveFormat = (LPWAVEFORMAT)pChunk;
Now that we know the audio format, we are better equipped to interpret the actual sound information in order to play it back. It's not necessary to be familiar with the structure members just yet.
Video Stream Specifics
The BITMAPINFO structure defines the format for a video stream. That structure contains one of the BITMAPINFOHEADER, BITMAPV4HEADER, or BITMAPV5HEADER structures, followed by the palette information if the image format is 8bits per pixel. Software for Windows 98 or Windows2000 should write the BITMAPV5HEADER, but for reading an AVI file we need to determine which version was stored in the file in order to be backward compatible. That's easiest by allocating and reading it all in one chunk like we did with the sound format.
LPBYTE pChunk = new BYTE[lSize]; if(!pChunk) // allocation error if(AVIStreamReadFormat(pStream, AVIStreamStart(pStream), pChunk, lSize)) // error
The reason why that's possible, is because each structure begins with the same information as BITMAPINFO, but adds a few extra members to the previous version. If you determine that you need these extra members for a project you're working on, it's easy to cast the data chunk over to the appropriate structure pointer:
// Only if you need to: LPBITMAPINFO pInfo = (LPBITMAPINFO)pChunk; DWORD biSize = pInfo->bmiHeader.biSize; switch(biSize) { case sizeof(BITMAPV5HEADER): // ... case sizeof(BITMAPV4HEADER): // ... case sizeof(BITMAPINFOHEADER): // ... };
The BITMAPINFO structure tells us a lot about the image format. It tells what type of compression is used, the frame size, bit depth, etc. That's all the necessary information one needs when converting image data over to a GDI HBITMAP, MFC CBitmap, LPDIRECTDRAWSURFACE, or custom format.
[size="3"] Processing an Audio Stream
Streams of this type are typically uncompressed, so it's probably best to describe that method. We'll start by determining the size of the audio data contained in the stream.
LONG lSize; if(AVIStreamRead(pStream, 0, AVISTREAMREAD_CONVENIENT, NULL, 0, &lSize, NULL)) // error
Since we already know the stream's format, we'll load the sound data into a byte buffer.
LPBYTE pBuffer = new BYTE[lSize]; if(!pBuffer) // error if(AVIStreamRead(pStream, 0, AVISTREAMREAD_CONVENIENT, pBuffer, lSize, NULL, NULL)) // error
So now with the sound format and data, it's a simple task to create a DirectSound buffer, play it back through a Win32 multimedia function, or custom library. Changing the function calls won't do anything special, but you can read about the parameters if you want in the online docs.
[size="3"] Processing a Video Stream
The great thing about AVIFile is that it handles decompression of video for us. We'll initialize that feature in the following code.
Since we determined what format the frames are stored in earlier, you can modify it slightly, or calculate a new format from scratch, and have AVIFile convert the frames into whatever format best suits your rendering system.
The PGETFRAME pointer is used by the system to handle the decompression of the video frames. The NULL parameter says I just want AVIFile to leave the image format the way it is. You can try passing a BITMAPINFO pointer, perhaps by changing the image format that was loaded before.
PGETFRAME pgf; pgf = AVIStreamGetFrameOpen(pStream, NULL); if(!pgf) // error
Now that the decompression system has been initialization, we can enter the loop that plucks and displays each frame for this video stream. AVIFile is organized so you only need one frame in memory at a time, allowing you to quickly play large files, but you can copy or buffer the frames as needed.
Next we'll determine which frame we need to pluck from the stream. Usually that's accomplished by incrementing the value lTime each millisecond via a multimedia timer, or calculating it via the difference in time between frame renderings. The API functions are then used to calculate a frame value based on the amount of time elapsed since the beginning of play. This allows accurate playback for whatever the file specifies as its playback speed, regardless of the time it takes us to render a frame. With this code you'll be able to synchronize the video with speech or game events. Alternatively you can calculate the lFrame variable through any means depending on what effect you're accomplishing.
// Precalculated: When stream is opened lEndTime = AVIStreamEndTime(pStream); // Calculated just before next frame is blitted if(lTime <= lEndTime) lFrame = AVIStreamTimeToSample(pStream, lTime); else // the video is done
With that information, it's easy to pluck a packed DIB from the video stream.
LPBITMAPINFOHEADER lpbi; lpbi = (LPBITMAPINFOHEADER)AVIStreamGetFrame(pgf, lFrame);
The packed DIB is comprised of a BITMAPINFOHEADER structure, followed by the palette information if needed, and then followed by the bitmap data. All of this is just one sequential block of memory, so it's possible to calculate the palette and bitmap pointers using pointer arithmetic.
// For 16, 24, or 32bit image formats LPBYTE pData = lpbi + lpbi->biSize; // For 8bit image formats LPBYTE pData = lpbi + lpbi->biSize + 256 * sizeof(RGBQUAD);
The image data that has been extracted is only good until the next time we call AVIStreamGetFrame, so it's important to display it to screen, copy it to a texture or bmp file, or whatever you want to do with it. I don't go into such details here, but you'll see how in the provided sample code.
When all of the frames have been processed, it's important to close down the decompression system as follows.
if(AVIStreamGetFrameClose(pgf)) // error
[size="3"] Cleaning up
After you're done with the streams, and file, you release them as follows. That's all there is to it! Hopefully I have helped you to understand this file format. Feel free to email me if you have any questions.
// Remember to release all streams AVIStreamRelease(pStream); AVIStreamRelease(pStream); AVIFileRelease(pAviFile); AVIFileExit();
[size="5"] [size="2"]
[size="5"]Conclusion
Did you skip the document just to get to the samples?
How can you have any pudding if you haven't finished your meat?
- Pink Floyd, "The Wall"
[size="3"] Sample One
The first sample plays an AVI file that was made by Klowner. This sample uses my CDirectDraw wrapper class to do the rendering. The file is first played forwards, and then played in reverse so the action is seamless. It's time synchronized so the visual frame rate is consistent with the frame rate specified by Klowner when he made the file. Each frame is also blitted with transparency, so the sequence can be superimposed over a backdrop during a game's action.
[size="3"] Sample Two, featuring the PowerRender API
The second sample shows a rotating teapot superimposed over the AVI file's action. It may look like the teapot is being stretched, skewed and zooming in and out, but I used PR's camera features namely field of view and aspect ratio to optimize those effects. This sample requires a hardware accelerator compatible with Microsoft's Direct3D in order to operate, but should be compatible with OpenGL, GLIDE, or software rendering depending on what you recompile it for. If you want more information on the professional PowerRender api, here's their site: Egerter software.
?[Visit my Web Site!!]ss
All sample code is subject the most current copyrights and/or disclaimers posted on my website.
PowerRender is a trademark of Egerter Software.
Direct3D and Microsoft are trademarks of Microsoft Coorporation.
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http://www.numdam.org/item/AIHPC_2005__22_4_385_0/ | On backward-time behavior of the solutions to the 2-D space periodic Navier-Stokes equations
Annales de l'I.H.P. Analyse non linéaire, Volume 22 (2005) no. 4, p. 385-401
@article{AIHPC_2005__22_4_385_0,
author = {Dascaliuc, Radu},
title = {On backward-time behavior of the solutions to the 2-D space periodic Navier-Stokes equations},
journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
publisher = {Elsevier},
volume = {22},
number = {4},
year = {2005},
pages = {385-401},
doi = {10.1016/j.anihpc.2004.10.001},
zbl = {1076.76021},
language = {en},
url = {http://www.numdam.org/item/AIHPC_2005__22_4_385_0}
}
Dascaliuc, Radu. On backward-time behavior of the solutions to the 2-D space periodic Navier-Stokes equations. Annales de l'I.H.P. Analyse non linéaire, Volume 22 (2005) no. 4, pp. 385-401. doi : 10.1016/j.anihpc.2004.10.001. http://www.numdam.org/item/AIHPC_2005__22_4_385_0/
[1] Bardos C., Tartar L., Sur l'unicité rétrograde des équations parabolique et quelques questiones voisines, Arch. Rational Mech. 50 (1973) 10-25. | MR 338517 | Zbl 0258.35039
[2] Constantin P., Foias C., Navier-Stokes Equations, Chicago Lectures in Math., University of Chicago Press, Chicago, 1988. | MR 972259 | Zbl 0687.35071
[3] Constantin P., Foias C., Kukavica I., Majda A., Dirichlet quotients and 2-d periodic Navier-Stokes equations, J. Math. Pures Appl. 76 (1997) 125-153. | MR 1432371 | Zbl 0874.35085
[4] Dascaliuc R., On the backward-time behavior of Burgers' original model for turbulence, Nonlinearity 16 (6) (2003) 1945-1965. | MR 2012849 | Zbl 02028750
[5] C. Foias, B. Nicolaenko, Some estimates on the nonlinear term of the Navier-Stokes equation, Preprint, 2003.
[6] Kukavica I., On the behavior of the solutions of the Kuramoto-Sivashinsky equations for negative time, J. Math. Anal. Appl. 166 (1992) 601-606. | MR 1160948 | Zbl 0788.35118
[7] I. Kukavica, M. Malcok, Backward behavior of solutions of Kuramoto-Sivashinsky equation, 2003, submitted for publication. | Zbl 1080.35121
[8] Richards I., On the gaps between numbers which are sums of two squares, Adv. in Math. 46 (1982) 1-2. | MR 676985 | Zbl 0501.10047
[9] Temam R., Navier-Stokes Equations and Nonlinear Functional Analysis, SIAM, Philadelphia, 1983. | MR 764933 | Zbl 0522.35002
[10] Vukadinovic J., On the backwards behavior of the solutions of the 2D periodic viscous Kamassa-Holm equations, J. Dynam. Differential Equations 14 (2) (2002). | MR 1878244 | Zbl 1007.35076
[11] J. Vukadinovic, On the backwards behavior of the solutions of the Kelvin-filtered 2D periodic Navier-Stokes equations, Ph.D. Thesis, Indiana University, 2002. | {"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": 0.1936333328485489, "perplexity": 5524.808401648624}, "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-2020-34/segments/1596439735823.29/warc/CC-MAIN-20200803170210-20200803200210-00396.warc.gz"} |
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## anonymous 5 years ago how do i solve this for x? x^2=1/2 and x^2=3/2 Delete Cancel Submit
• This Question is Closed
1. anonymous
• 5 years ago
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square root both sides.
2. anonymous
• 5 years ago
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right, but i don't understand how to do that. the example given is this: x^2=2/3 and x^2=3/5 and somehow they get this: x=$\pm \sqrt{6}/3 and \pm \sqrt{15}/5$
3. anonymous
• 5 years ago
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i don't understand the steps between the two
4. anonymous
• 5 years ago
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x=+sqrt(1/2) or x+-sqrt(1/2)
5. anonymous
• 5 years ago
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the same for 3/2
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Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy. | {"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": 0.999701738357544, "perplexity": 12895.900914808479}, "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/1484560281069.89/warc/CC-MAIN-20170116095121-00134-ip-10-171-10-70.ec2.internal.warc.gz"} |
http://tex.stackexchange.com/questions/34670/babel-shorthand-doesnt-work-in-macros/34671 | # babel shorthand "| doesn't work in macros
The package babel with the ngerman option (and most other languages as well, but not english) provides the shorthand "|, which prevents a ligature at the given position (see p. 81 of the babel documentation, e.g. Auf"|lage will result in the word Auflage without an fl-ligature (as is desired because, in German, you don't want ligatures across morpheme borders).
However, when placed in a macro, "| doesn't work anymore. Why is this and how can I circumvent it?
\documentclass{article}
%\usepackage[T1]{fontenc}% doesn't help
\usepackage[ngerman]{babel}
\newcommand{\foo}{"|}
\begin{document}
ff
f"|f
f\foo f
\end{document}
-
Let me note for searchability that this is also the case with environment definitions. – Raphael Nov 13 '13 at 9:56
It works if you switch the shorthand on before defining the command, or if you define the command after \begin{document} when shorthands are active.
As Joseph commented, it's recommendable to switch it off immediately afterwards, so that the active shorthand doesn't affect other commands.
\documentclass{article}
\usepackage[ngerman]{babel}
\shorthandon{"}
\newcommand{\foo}{"|}
\shorthandoff{"}
\begin{document}
ff
f"|f
f\foo f
\end{document}
Alternatively, you could switch it on locally within the macro definition, similar as written here by egreg, and made robust, so it can be used within moving arguments, such as \chapter and \section headings and captions.
\DeclareRobustCommand{\foo}{\shorthandon{"}\scantokens{"|\endinput}}
However, it might be useful to have a part in the preamble where shorthands are active, as in the first solution, so you can use them in your commands such as in text arguments to macros.
-
I'd also switch the shorthand off after the definition, as other parts of the preamble might otherwise be affected. – Joseph Wright Nov 13 '11 at 10:05
You should also switch it off using \shorthandoff{"} after the definition. Otherwise you may run into catcode problems at the preamble (e.g. loading other packages after the definition). That's the reason for babel does not active the shorthands while loading the language file but just after \begin{document}. – Schweinebacke Nov 13 '11 at 10:06 | {"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": 0.8546541929244995, "perplexity": 2338.3281940682477}, "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-2015-22/segments/1432207928562.33/warc/CC-MAIN-20150521113208-00113-ip-10-180-206-219.ec2.internal.warc.gz"} |
http://www.risc.jku.at/publications/show-bib.php?activity_id=3410 | |
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• @article{RISC3410,
author = {E. Kartashova and S. Nazarenko and O. Rudenko},
title = {{Resonant interactions of nonlinear water waves in a finite basin}},
language = {english},
abstract = {We study exact four-wave resonances among gravity water waves in a square box with periodic boundary conditions. We show that these resonant quartets are linked with each other by shared Fourier modes in such a way that they form independent clusters. These clusters can be formed by two types of quartets: (1) {\it angle-resonances} which cannot directly cascade energy but which can redistribute it among the initially excited modes and (2) {\it scale-resonances} which are much more rare but which are the only ones that can transfer energy between different scales. We find such resonant quartets and their clusters numerically on the set of 1000 x 1000 modes, classify and quantify them and discuss consequences of the obtained cluster structure for the wavefield evolution. Finite box effects and associated resonant interaction among discrete wave modes appear to be important in most numerical and laboratory experiments on the deep water gravity waves, and our work is aimed at aiding the interpretation of the experimental and numerical data.},
journal = {Physical Review E},
volume = {78 },
number = {016304},
pages = {1--9},
publisher = {American Physical Society},
isbn_issn = {1539-3755 (print) , 1550-2376 (online)},
year = {2008},
refereed = {yes},
length = {9}, | {"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": 0.8675938844680786, "perplexity": 2311.3775631437657}, "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-2017-47/segments/1510934806124.52/warc/CC-MAIN-20171120183849-20171120203849-00503.warc.gz"} |
https://www.mathworks.com/matlabcentral/answers/6266-unresolved-external-errors-when-compiling-an-s-funtion-in-vs2008?requestedDomain=www.mathworks.com&nocookie=true | ## Unresolved External errors when compiling an S-Funtion in VS2008
on 26 Apr 2011
### Richard Beranek (view profile)
[EDIT: 20110609 23:06 CDT - reformat - WDR]
I am trying to compile an S-Function using VS 2008.
I have followed the instructions to compile an s-function from
I have included the relevant libraries (libmx.lib libmat.lib libmex.lib) their linking directories as well as included "mex.h". However, I still get the following errors from the compiler:
1>Control.obj : error LNK2001: unresolved external symbol _mexWarnMsgTxt
1>Control.obj : error LNK2001: unresolved external symbol _mexCallMATLAB
1>Control.obj : error LNK2001: unresolved external symbol _mxCreateString
1>Control.obj : error LNK2001: unresolved external symbol _mxGetClassID
1>Control.obj : error LNK2001: unresolved external symbol _mxGetPr
1>Control.obj : error LNK2001: unresolved external symbol _mxCreateDoubleMatrix_730
1>Control.obj : error LNK2001: unresolved external symbol _mxIsNumeric
1>Control.obj : error LNK2001: unresolved external symbol _mxIsComplex
1>Control.obj : error LNK2001: unresolved external symbol _mxGetN
1>Control.obj : error LNK2001: unresolved external symbol _mxGetM
1>Control.obj : error LNK2001: unresolved external symbol _mexErrMsgTxt
1>Control.obj : error LNK2001: unresolved external symbol _mxCalloc
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### Richard Beranek (view profile)
on 28 Apr 2011
I ultimately tracked the problem down. The issue was that I was compiling on a 64 bit system. This meant I had to configure the compiler to target an x64 platform (not use default win32) as well as recompile my own libraries to target an x64 platform. This has resolved the issue and I am able to compile my s-function in both visual studio and using 'mex' command in matlab.
### Kaustubha Govind (view profile)
on 26 Apr 2011
Have you also ensured step 4 (Add "\$MATLABROOT\extern\lib\win32\microsoft" in the options Linker->General->Additional Library Directories). Note that if you have 64-bit MATLAB, you need to swap win32 with win64. Double-check that the relevant libraries are present in whatever folder you add to the directories list.
Richard Beranek
### Richard Beranek (view profile)
on 26 Apr 2011
Yes I am running a 64-bit system and I have switched the include and library directories for the 64-bit locations.
Additionally VS spits out an error if it cannot find the lib files that are added in the dependencies. So it does not seem like that is the issue.
Kaustubha Govind
### Kaustubha Govind (view profile)
on 26 Apr 2011
Have you also configured MSVC to target 64-bit platforms (I think it tries to build a 32-bit DLL by default). See http://msdn.microsoft.com/en-us/library/9yb4317s%28v=vs.80%29.aspx
Also, set .mexw64 as the extension.
MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi | {"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": 0.913888156414032, "perplexity": 18872.558459462463}, "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-2017-17/segments/1492917123048.37/warc/CC-MAIN-20170423031203-00056-ip-10-145-167-34.ec2.internal.warc.gz"} |
https://tex.stackexchange.com/questions/601023/adding-horizental-lines/601026#601026 | how can I add a horizental line above my page and write above it. like that
• You are looking for a feature called "headers". You can search this site. See also the fancyhdr package. Welcome to the site. Jun 12 at 23:41
• See here for example: overleaf.com/learn/latex/Headers_and_footers Jun 13 at 1:37
Here's an example that is based on here. The manual for the package fancyhdr can be found here.
% Based on https://overleaf.com/learn/latex/Headers_and_footers
\documentclass{book}
\usepackage{blindtext}
\usepackage{fancyhdr} % <-- Important package!
\pagestyle{fancy}
\fancyhf{} % Clear all header and footer fields and then re-define the field, see below.
\fancyfoot[CE,CO]{\leftmark}
\fancyfoot[LE,RO]{\thepage}
% E for even page
% O for odd page
% L for left side
% C for centered
% R for right side | {"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": 0.5338776707649231, "perplexity": 4159.987473924333}, "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-2021-49/segments/1637964359082.76/warc/CC-MAIN-20211130232232-20211201022232-00225.warc.gz"} |
https://www.physicsforums.com/threads/totally-lost-any-help-would-be-greatly-appreciated.136216/ | # Totally lost, any help would be greatly appreciated
• Start date
#### Tonyt88
62
0
A particle of mass m is subject to a force F(v) = -m(alpha)v^2. The initial position is zero, and the initial speed is v nought. Find x(t)
Related Introductory Physics Homework Help News on Phys.org
#### kreil
Gold Member
667
66
what is alpha in this problem?
#### Tonyt88
62
0
Nothing has been suggested for what alpha is so I really couldn't tell you, sorry perhaps this is why this problem is totally puzzling.
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1K | {"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": 0.8186668753623962, "perplexity": 5313.787206730398}, "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/1573496668004.65/warc/CC-MAIN-20191114053752-20191114081752-00419.warc.gz"} |
https://brilliant.org/problems/disguised-problem/ | # Disguised problem!
Calculus Level pending
Let a function $$f$$ be defined as
$f(x) = \max \lbrace x, -x \rbrace$
The distance of the point from origin where it is non-differentiable can be written as $$\displaystyle\frac{a}{b}$$ .
Find the value of $$\displaystyle ab$$.
• This is part of this set
• This is original.
× | {"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": 0.9948384165763855, "perplexity": 1153.550241066697}, "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-2017-39/segments/1505818686043.16/warc/CC-MAIN-20170919221032-20170920001032-00433.warc.gz"} |
https://scholar.princeton.edu/kathrint/ | Welcome to my Princeton Open Scholar homepage! I am glad you found me here. Thanks for stopping by.
These pages tell you a little bit more about who I am and what I do and why I am here. This includes my present and past research, courses I have taught in past, and all sorts of other things. You may find the odd reocurring theme...be surprised (or not).
If you have got any questions, feedback, or any other remarks, why don't you drop me an email? It's very simple. Just click on "contact" -- it's right there $$\uparrow$$ at the very top of my page. Or you can just click here. As you made it here in first place, I am sure you will figure it out.
My very best,
Kat | {"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": 0.15954414010047913, "perplexity": 1018.1517217181819}, "config": {"markdown_headings": true, "markdown_code": false, "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-2019-39/segments/1568514576047.85/warc/CC-MAIN-20190923043830-20190923065830-00531.warc.gz"} |
http://sellingcompassion.blogspot.com/2009/02/vastly-more-persuasive.html | ### "vastly more persuasive" ???
P Q $P \and Q$ $P \or Q$ $P \underline{\or} Q$ $P \underline{\and} Q$ $P \rightarrow Q$ $P \leftarrow Q$
F F F F F T T T
F T F T T F T F
T F F T T F F T
T T T T F T T T
Erik Marcus, undermining his own message, wrote:
"If every activist in the animal protection movement read and understood the Wikipedia link above [or here], we would collectively be vastly more persuasive and credible."
Sadly, Marcus doesn't seem to realize that persuasiveness isn't strongly correlated OR caused by an understanding of causal relationships.
Logicians are no more persuasive to the general human population than marketers. In fact, they're often less so.
Let's look up the Wikipedia entry for persuasion:
Persuasion is a form of social influence. It is the process of guiding people toward the adoption of an idea, attitude, or action by rational and symbolic (though not always logical) means. It is strategy of problem-solving relying on "appeals" rather than coercion. According to Aristotle, "Rhetoric is the art of discovering, in a particular case, the available means of persuasion."
Methods include appeals to reason as well as appeals to emotion, subliminal messages, seduction, peer pressure, etc.
McDonald's doesn't put toys in Happy Meals because it makes McDonald's appear more credible or reasonable, they do it to persuade children to desire Happy Meals.
(Read the updated version at Vegan Soapbox >> ) | {"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": 6, "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": 0.39016425609588623, "perplexity": 2848.184535294919}, "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/1512948523222.39/warc/CC-MAIN-20171213123757-20171213143757-00778.warc.gz"} |
https://www.ias.ac.in/describe/article/boms/039/01/0241-0248 | • Electrochemical supercapacitor behaviour of functionalized candle flame carbon soot
• # Fulltext
https://www.ias.ac.in/article/fulltext/boms/039/01/0241-0248
• # Keywords
Electrode; nanoparticles; carbon soot; functionalized carbon; supercapacitor.
• # Abstract
The electrochemical supercapacitor behaviour of bare, washed and nitric acid functionalized candle flame carbon soots were reported. Crystallinity and the morphology of the candle soots were recorded using X-ray diffraction analysis, scanning and transmission electron microscopy, respectively. The nitric acid functionalized candle soot showed an improved Brunauer–Emmett–Teller surface area of 137.93 from 87.495 m$^2$ g$^{−1}$ of washed candle soot. The presence of various functional groups in candle soots and the development of oxygen functionalities in the functionalized candle soot were examined through Fourier transform infrared spectroscopy and energy-dispersive X-ray analysis. Raman spectra showed the characteristic peaks corresponding to the D (diamond) and G (graphite) phase of carbon present in the candle soots. The electrochemical characterization was performed by cyclic voltammetry, galvanostatic charge/discharge test and impedance spectroscopy in 1MH2SO4 electrolyte. The functionalized candle soot electrode showed an enhanced specific capacitance value of 187 F g$^{−1}$ at 0.15 A g$^{−1}$ discharge current density, which is much higher than that of bare and washed candle soot electrodes.
• # Author Affiliations
1. Department of Chemistry, Dongguk University-Seoul, Seoul 100 715, Republic of Korea
2. Department of Ceramic Engineering, Gangneung-Wonju National University, Gangneung 210 702, Republic of Korea
• # Bulletin of Materials Science
Volume 43, 2020
All articles
Continuous Article Publishing mode
• # Editorial Note on Continuous Article Publication
Posted on July 25, 2019 | {"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": 0.3877672255039215, "perplexity": 20542.145746188817}, "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-2020-29/segments/1593655890566.2/warc/CC-MAIN-20200706222442-20200707012442-00310.warc.gz"} |
http://www.bconverged.com/calculix/doc/ccx/html/node145.html | Convective heat flux
Next: Radiative heat flux Up: Loading Previous: Distributed heat flux Contents
### Convective heat flux
Convective heat flux is a flux depending on the temperature difference between the body and the adjacent fluid (liquid or gas) and is triggered by the *FILM card. It takes the form
(186)
where is the a flux normal to the surface, is the film coefficient, is the body temperature and is the environment fluid temperature (also called sink temperature). Generally, the sink temperature is known. If it is not, it is an unknown in the system. Physically, the convection along the surface can be forced or free. Forced convection means that the mass flow rate of the adjacent fluid (gas or liquid) is known and its temperature is the result of heat exchange between body and fluid. This case can be simulated by CalculiX by defining network elements and using the *BOUNDARY card for the first degree of freedom in the midside node of the element. Free convection, for which the mass flow rate is a n unknown too and a result of temperature differences, cannot be simulated.
Next: Radiative heat flux Up: Loading Previous: Distributed heat flux Contents
guido dhondt 2012-10-06 | {"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": 0.8928812146186829, "perplexity": 1039.3013079893271}, "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-2016-26/segments/1466783393442.26/warc/CC-MAIN-20160624154953-00116-ip-10-164-35-72.ec2.internal.warc.gz"} |
http://mathoverflow.net/questions/40618/uncomputability-of-the-identity-relation-on-computable-real-numbers | Uncomputability of the identity relation on computable real numbers
Let $f_{=}$ be a function from $\mathbb{R}^{2}$ be defined as follows: (1) if $x = y$ then $f_{=}(x,y) = 1$; (2) $f_{x,y} = 0$ otherwise.
I would like to have a proof for / a reference to a textbook proof of the following theorem (if it indeed is a theorem):
$f_{=}$ is uncomputable even if one restricts the domain of $f_{=}$ to a proper subset of $\mathbb{R}^{2}$, viz. the set of the computable real numbers
Thanks!
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You should specify which model of computation over the reals you have in mind. – wood Sep 30 '10 at 14:18
Rice's theorem: en.wikipedia.org/wiki/Rice%27s_theorem – Mark Sapir Sep 30 '10 at 14:20
@Wood: The question is specific enough. There is no ambiguity in the term "computable real number". – Mark Sapir Sep 30 '10 at 14:21
@Mark: I agree for the term "computable real number". But he is referring to a computable function over the reals. Does he mean the Blum-shub-Smale model or something else. I think there maybe different models. When I first read the question, I thought trivially yes under der BSS model. – wood Sep 30 '10 at 14:27
@Wood: He restricts the function to computable reals. The function takes Turing machines computing $x,y$ and produces 1 or 0. By Rice theorem the function is not computable: you cannot check if two Turing machines recognize the same language. – Mark Sapir Sep 30 '10 at 15:26
Suppose that $f_=$ is computable when restricted to computable real numbers, which means that there exists a Turing machine that, given as input the encoding of two Turing machines $M_1$ and $M_2$ that compute the fractional digits of two computable real numbers $r_1$ and $r_2$ in $[0,1]$, produces $1$ if $r_1 = r_2$ and $0$ otherwise. I will use this assumption to show that the Halting problem is also computable, which is impossible.
Given a Turing machine $M$ and an input $x$ for which we want to know if $M$ on input $x$ halts or not, let $M_x$ be the Turing machine that acts as follows: given an integer $i$ as input, $M_x$ starts a simulation of $M$ on input $x$ for up to $i$ steps, and if the simulation does not halt within that number of steps, it outputs $0$ and otherwise it outputs $1$. By definition, $M_x$ computes the digits of a computable real number (more precisely, it computes the $i$-th digit for every given $i$). Moreover, that real number is $0$ if $M$ on input $x$ does not halt, and the real number $0.0\cdots 011 \cdots = 2^{-k}$ otherwise for some $k \geq 1$. In other words, $M_x$ computes the real number $0$ if and only if $M$ on input $x$ does not halt. To complete the argument, note that $0$ is a computable real number, so if you could tell whether two computable real numbers are equal you would also be able to tell if $M$ on input $x$ halts or not.
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The main difficulty in finding a reference for this is that it's so well known :). The fact that equality of reals is only (negatively) semidecidable is a basic and important result in both computable analysis and constructive analysis.
The underlying phenomenon here is about continuity. As Gerald Edgar says, the equality function is not continuous (in particular, it's not sequentially continuous). The proof that slimton presents shows not only that it's discontinuous, but that it's effectively discontinuous: we can make an effective sequence of effective reals that witnesses the discontinuity.
This is closely related to the type-2 functional $E\colon \{0,1\}^\omega \to \{0,1\}$ defined such that $E(f) = 1 \leftrightarrow (\exists k)(f(k) = 1)$. This functional is not computable.
If you look more deeply at slimton's proof, you see that he actually proves that if you had a uniform way to test equality of reals, then you would have a uniform way to compute $E$. In particular the problem of computing equality of computable reals is no easier than that of computing $E$ on computable reals. It can be shown with only a little more work that these are equivalent problems.
This phenomenon is a particular instance of a general phenomenon first studied by Grilliot [1] and now called Grilliot's trick: a functional $\Phi$ is effectively discontinuous if and only if $E$ is computable from $\Phi$. In particular, no effectively discontinuous functional is computable.
1: Thomas J. Grilliot, "On Effectively Discontinuous Type-2 Objects", Journal of Symbolic Logic v. 36, n. 2 (Jun., 1971), pp. 245-248. http://www.jstor.org/stable/2270259
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Regarding who might have observed it first, according to this paper/book "the logician H. Gordon Rice proved what Borel had already observed informally, namely that equality is not decidable for computable real numbers." – Respawned Fluff Feb 22 at 13:41
Thanks. The linked paper is "Computability and analysis: the legacy of Alan Turing" by Avigad and Brattka, arxiv.org/pdf/1206.3431v2.pdf . The citation they give is: H. Gordon Rice. Recursive real numbers. Proceedings of the American Mathematical Society, 5:784–791, 1954. – Carl Mummert Feb 22 at 13:51
Aren't computable functions of reals automatically continuous? And isn't your function discontinuous? Of course you need a definition of computable in this setting to make sense of this...
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If you take away some neighbourhood of the diagonal the continuity obstruction vanishes (the OP allowed proper subsets of R^2). – Peter Arndt Sep 30 '10 at 15:37
I thought the question only allowed one proper subset, namely the one consisting only of pairs of computable reals. – Carl Mummert Sep 30 '10 at 19:03
I guess you are right, Carl. – Peter Arndt Sep 30 '10 at 20:40
It is entirely reasonable to ask for a continuous and computable equality-test function on~$\mathbb R$. The unreasonable thing is to expect it to take values in the discrete two-element space $\mathbf 2$.
The truth-value space that we need to use is the Sierpinski space, for which I write $\Sigma$. It has (in the classical interpretation) two elements,
• $\top$, for which $\lbrace\top\rbrace\subset\Sigma$ is an open subspace, and
• $\bot$, for which $\lbrace\bot\rbrace\subset\Sigma$ is a closed subspace.
This space has the property that there is a three-way bijection amongst
• continuous functions $f:X\to\Sigma$;
• open subspaces $U=f^{-1}(\top)\subset X$ and
• closed subspaces $C=f^{-1}(\bot)\subset X$ for any space $X$.
This is like the subobject classifier $\Omega$ in a topos, where "open subspace" becomes "subobject". Indeed, both in set theory and topology the classification properties are rather trivial in the classical case, but become powerful definitions when read constructively.
In particular, a space $X$ is Hausdorff iff the diagonal $X\subset X\times X$ is closed. This happens iff there is a continuous function $$(\neq):X\times X\to\Sigma$$ for which $$(\neq)(x,y) = \bot \iff x=y.$$
In the discrete space $\mathbf 2$ both points are both open and closed and there is a negation function $\lnot:\mathbf 2\to\mathbf 2$ that swaps them.
All of this is meaningful in both general topology and recursion theory, replacing - continuous function by computable function and - open subspace by recursively enumerable subspace.
In particular, a computable function $f:X\to\Sigma$ is one that may or may not terminate but otherwise has no return value, so it is like $\mathtt{void}$ in $C$ or $\mathtt{unit}$ in ML. Then $\top$ denotes termination and $\bot$ divergence.
There is no negation function on this $\Sigma$ because if there were it would be exactly a solution of the Halting Problem.
In particular, slimton is right in saying that a positive solution to the question as originally posed would be equivalent to the Halting Problem.
The interpretation of computation in general topology was pioneered by Dana Scott in the 1970s. Conversely, my research programme Abstract Stone Duality is about reformulating topology to make it equivalent to computation.
The best introduction to this programme for the general mathematician is my paper A Lambda Calculus for Real Analysis.
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Dan Richardson in Bath has extensively studied the problem of recognizing zero under various hypotheses. I would be hard-pressed to give you an account of the details, because there is a lot of subtle and surprising results, but his page has all his papers and I'm sure you can find something of interest there.
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https://chem.libretexts.org/Courses/Lumen_Learning/Book%3A_Statistics_for_the_Social_Sciences_(Lumen)/11%3A_10-_Inference_for_Means/11.25%3A_Distribution_of_Sample_Means_(3_of_4) | # 11.25: Distribution of Sample Means (3 of 4)
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### Learning Objectives
• Describe the sampling distribution of sample means.
### Shape of the Sampling Distribution of Means
Now we investigate the shape of the sampling distribution of sample means. When we discussed the sampling distribution of sample proportions, we learned that this distribution is approximately normal if np ≥ 10 and n(1 – p) ≥ 10. In other words, we had a guideline based on sample size for determining the conditions under which we could use a normal curve to do probability calculations for sample proportions.
Now we investigate these questions:
• When will the distribution of sample means be approximately normal?
• Does it depend on the size of the sample?
• What happens if the distribution of the variable in the population is heavily skewed?
The following simulation video helps us investigate these questions.
### WalkThrough Simulation
A YouTube element has been excluded from this version of the text. You can view it online here: http://pb.libretexts.org/sss/?p=382
### Comment
Are you surprised that a variable with a skewed distribution in the population can have a sampling distribution that is approximately normal? This discovery is probably the single most important result presented in introductory statistics courses. It is called the central limit theorem, which says that for large samples, the sampling distribution of sample means is approximately normal. This theorum is important! Inference procedures, such as hypothesis tests and confidence intervals, are based on a normal model for the sampling distribution. The central limit theorem assures us that we can use a normal probability model for sample means without knowing anything about the shape of the distribution of the variable in the population. All we have to do is collect large samples.
How large a sample size do we need to assume that sample means will be normally distributed? It really depends on the population distribution, as we saw in the simulation. The more skewed the distribution in the population, the larger the samples we need in order to use a normal model for the sampling distribution.
The general guideline is that samples of size greater than 30 will have a fairly normal distribution regardless of the shape of the distribution of the variable in the population. But if a population is strongly skewed, it is safer to use larger samples.
### Learn By Doing
The distribution of incomes is strongly skewed to the right for individuals in the U.S. The following histograms represent mean income from 200 samples randomly selected from the U.S. population. One histogram is based on samples of size of n = 4, one on samples of size of n = 40, and one on samples of size of n = 100.
https://assessments.lumenlearning.co...sessments/3681
### Summary
• Let’s say we have a quantitative data set from a population with mean μ and standard deviation σ.The model for the theoretical sampling distribution of means of all random samples of size n has the following properties:
• The mean of the sampling distribution of means is μ.
• The standard deviation of the sampling distribution of means is .
• Notice that as n grows, the standard deviation of the sampling distribution of means shrinks.
• For large enough sample size, the sampling distribution of means is approximately normal (even if population is not normal).
• If a variable has a skewed distribution for individuals in the population, a larger sample size is needed to ensure that the sampling distribution has a normal shape.
• The general rule is that if n is more than 30, then the sampling distribution of means will be approximately normal. However, if the population is already normal, then any sample size will produce a normal sampling distribution.
### Comment
Notice that the size of the population is not mentioned in our discussion of sampling distributions. From our discussion, we know the following:
• The means from larger samples have less variability, so larger samples give more accurate estimates of the population mean.
• The means from larger samples have a distribution with a shape that is closer to normal.
These statements are true regardless of the size of the population as long as the population is large. To illustrate this point, we compare a distribution of sample means from two populations of different sizes. Population A has 10,000 newborns. Population B has 20,000 newborns. For each population, the mean and standard deviation of individual birth weights is the same: μ = 3,500 and σ = 500.
We selected 525 random samples of 100 babies from each population and made a histogram of the sample means. We did this twice for population A, so two of the histograms represent 525 samples from the same population. As expected, there are some differences in the samples collected due to random chance. Comparing these two histograms gives us a sense of how much variation we can expect from the process of selecting random samples. Notice that the histogram of sample means from the larger population B has a similar shape, center, and spread to the histograms from population A.
### What’s the Main Point?
The size of the population does not affect the variability of the sample means. Size matters if we are talking about sample size for random samples, but size does not matter if we are talking about population size as long as the population is large. | {"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": 0.961612343788147, "perplexity": 241.98075296941497}, "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-2022-33/segments/1659882570977.50/warc/CC-MAIN-20220809124724-20220809154724-00645.warc.gz"} |
https://www.physicsforums.com/threads/passage-from-the-book-relativity-i-am-not-able-to-understand.629134/ | # Passage from the book relativity i am not able to understand
1. Aug 17, 2012
### RohitRmB
Below is a passage from a book "RELATIVITY THE SPECIAL AND GENERAL THEORY by ALBERT EINSTEIN" and i am not able to understand the trajectories of the stone from the train and from the ground.
I stand at the window of a railway carriage which is travelling uniformly, and drop a stone on the embankment, without throwing it. Then, disregarding the influence of the air resistance, I see the stone descend in a straight line. A pedestrian who observes the misdeed from the footpath notices that the stone falls to earth in a parabolic curve. I now ask: Do the “positions” traversed by the stone lie “in reality” on a straight line or on a parabola?"
2. Aug 17, 2012
### Mentz114
Both. It depends on your point of view. Relative to the train the stone has no horizontal velocity but to the pedestrian it has some.
3. Aug 17, 2012
### tiny-tim
Hi RohitRmB!
The train is moving horizontally with speed v.
The stone is dropped, which means that it receives no impulse, so its initial velocity is also v horizontally (and 0 vertically).
So it follows a parabola (as seen by the pedestrian), with vx = v, so x = vt, y = -1/2 gt2.
Since you are on the train, your vx is the same as the stone, so you are always vertically above the stone.
So in your frame (the train's frame) of reference, the horizontal component of velocity of the stone is always 0 …
ie, you see the stone fallng vertically (in a straight line)
4. Aug 17, 2012
### HallsofIvy
Staff Emeritus
Your assumption that one of the "parabola" or "straight" is "real" is in error. The path depends on the observer. (And this has nothing to do with Einstein's relativity. This is result of Galillean relativity.)
5. Aug 18, 2012
### RohitRmB
if i were standing on a moving train and i drop a stone, neglecting the effect of air, would'nt i see it moving backward because when i leave the stone from my hands, even when i am still standing on the train, even when initial the stone was at rest relative to me?
6. Aug 18, 2012
### tiny-tim
Hi RohitRmB!
no, it's because the stone was at rest relative to you
that it starts with the same velocity that you had, ie v horizontally and 0 vertically
since there are no horizontal forces on it, its horizontal component of velocity will always be 0, the same as yours
7. Aug 18, 2012
### RohitRmB
But meanwhile it is falling, i am moving ahead with the train, whereas there is no horizontal component of velocity with the stone, so would'nt it appear to be going in opposite direction to me?
8. Aug 18, 2012
### tiny-tim
yes there is!!
it starts with the same horizontal component that you had
9. Aug 18, 2012
### Mentz114
The first post tells you that there is a horizontal component in the pedestrian frame - pay attention !
10. Aug 18, 2012
### ghwellsjr
Next time you're riding in a car, why don't you try the experiment? Just drop something and see if it appears to you to fall straight down or go flying backwards. As long as you drop it within the car it will go straight down. If you drop it out the window, the air will force it backwards, but your quote said "disregarding the influence of the air resistance", which, of course, you can't do, but you have to do what Einstein said later on in his book in chapter 7:
"We shall imagine the air above [our embankment] to have been removed".
11. Aug 18, 2012
### cepheid
Staff Emeritus
Actually there is. After all, it had a horizontal component of velocity when it was moving along with the train, and it retains that after being dropped. For more details, try Googling Newton's First Law of Motion.
Halls, bear in mind that RohitRmB wasn't necessarily assuming that. This question here:
was in fact posed by Einstein, in the book.
12. Aug 19, 2012
### RohitRmB
thanks everybody, i have understood and my problem is now solved.
actually at first i was not able to imagine that when i leave the stone, the stone is now disconnected from my hand but it still moves forward along with me, so after leaving the stone from my hand as i move forward in the train the stone is also moving at the same speed with me, and the gravitational force acting on the stone is perpendicular to the direction of velocity so it will not affect its horizontal velocity, so i will see it falling straight down.
where as for a observer on the ground, the stone has a positive horizontal velocity as well as vertical velocity downwards, so for him it follows a parabolic trajectory towards the ground.
13. Aug 19, 2012
### RohitRmB
first i was not able to visualize
Similar Discussions: Passage from the book relativity i am not able to understand | {"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": 0.8344855904579163, "perplexity": 754.181304254155}, "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-2017-51/segments/1512948515313.13/warc/CC-MAIN-20171212095356-20171212115356-00412.warc.gz"} |
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# How many ways can a selection be done of 5 letters out of 5
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How many ways can a selection be done of 5 letters out of 5 [#permalink]
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How many ways can a selection be done of 5 letters out of 5 A's, 4B's, 3C's, 2D's and 1 E.
A. 60
B. 75
C. 71
D. 121
E. 221
[Reveal] Spoiler: OA
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Re: selection be done of 5 letters [#permalink]
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07 Feb 2012, 05:19
krishnasty wrote:
How many ways can a selection be done of 5 letters out of 5 A's, 4B's, 3C's, 2D's and 1 E.
A. 60
B. 75
C. 71
D. 121
E. 221
Notice that you won't see such question on the GMAT. So, just for fun.
We have the following letters: {AAAAA}, {BBBB}, {CCC}, {DD}, {E}
There are 7 different cases of 5 letter selections possible:
(5) - all letters are alike - 1 way, all A's;
(4, 1) - 4 letters are alike and 1 different - $$C^1_2*C^1_4=8$$, where $$C^1_2$$ is # of ways to choose which letter provides us with 4 letters from 2 (A or B) and $$C^1_4$$ is # of ways to choose 5th letter from 4 letters left;
(3, 2) - 3 letters are alike and other 2 are also alike - $$C^1_3*C^1_3=9$$, where $$C^1_3$$ is # of ways to choose which letter provides us with 3 letters from 3 (A, B or C) and $$C^1_3$$ is # of ways to choose which letter provides us with 2 letters from 3 (for example if we choose A for 3 letters then we can choose from B, C or D for 2 letters);
(3, 1, 1) - 3 letters are alike and other 2 are different - $$C^1_3*C^2_4=18$$, where $$C^1_3$$ is # of ways to choose which letter provides us with 3 letters from 3 (A, B or C) and $$C^2_4$$ is # of ways to choose which 2 letters provides us with one letter each;
(2, 2, 1) - 2 letters are alike, another 2 letters are also alike and 1 is different - $$C^2_4*C^1_3=18$$, where $$C^2_4$$ is # of ways to choose which 2 letters provides us with 2 letters from 4 (A, B, C or D) and $$C^1_3$$ is # of ways to choose which provides us with 5th letter from 3 letters left;
(2, 1, 1, 1) - 2 letters are alike and other 3 are different - - $$C^1_4*C^3_4=16$$, where $$C^1_4$$ is # of ways to choose which letter provides us with 2 letters from 4 (A, B, C or D) and $$C^3_4$$ is # of ways to choose which 3 letters out of 4 provides us with one letter each;
(1, 1, 1, 1, 1) - all letters are distinct - 1 way (A, B, C, D, E).
Total: 1+8+9+18+18+16+1=71.
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Re: How many ways can a selection be done of 5 letters out of 5 [#permalink]
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07 Feb 2012, 06:50
Even though it would not appear on GMAT, it is still a good questions to tackle. i am always weak with combinations.
Re: How many ways can a selection be done of 5 letters out of 5 [#permalink] 07 Feb 2012, 06:50
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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": 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": 0.5089825987815857, "perplexity": 1502.687510626828}, "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-2016-44/segments/1476988721405.66/warc/CC-MAIN-20161020183841-00414-ip-10-171-6-4.ec2.internal.warc.gz"} |
https://www.jw.org/en/publications/bible/king-james-version/books/zechariah/14/ | # Zechariah 14:1-21
14 Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee. 2 For I will gather all nations against Jerusalem to battle; and the city shall be taken, and the houses rifled, and the women ravished; and half of the city shall go forth into captivity, and the residue of the people shall not be cut off from the city. 3 Then shall the LORD go forth, and fight against those nations, as when he fought in the day of battle. 4 And his feet shall stand in that day upon the mount of Olives, which is before Jerusalem on the east, and the mount of Olives shall cleave in the midst thereof toward the east and toward the west, and there shall be a very great valley; and half of the mountain shall remove toward the north, and half of it toward the south. 5 And ye shall flee to the valley of the mountains; for the valley of the mountains shall reach unto Azal: yea, ye shall flee, like as ye fled from before the earthquake in the days of Uzziah king of Judah: and the LORD my God shall come, and all the saints with thee. 6 And it shall come to pass in that day, that the light shall not be clear, nor dark: 7 But it shall be one day which shall be known to the LORD, not day, nor night: but it shall come to pass, that at evening time it shall be light. 8 And it shall be in that day, that living waters shall go out from Jerusalem; half of them toward the former sea, and half of them toward the hinder sea: in summer and in winter shall it be. 9 And the LORD shall be king over all the earth: in that day shall there be one LORD, and his name one. 10 All the land shall be turned as a plain from Geba to Rimmon south of Jerusalem: and it shall be lifted up, and inhabited in her place, from Benjamin’s gate unto the place of the first gate, unto the corner gate, and from the tower of Hananeel unto the king’s winepresses. 11 And men shall dwell in it, and there shall be no more utter destruction; but Jerusalem shall be safely inhabited. 12 And this shall be the plague wherewith the LORD will smite all the people that have fought against Jerusalem; Their flesh shall consume away while they stand upon their feet, and their eyes shall consume away in their holes, and their tongue shall consume away in their mouth. 13 And it shall come to pass in that day, that a great tumult from the LORD shall be among them; and they shall lay hold every one on the hand of his neighbour, and his hand shall rise up against the hand of his neighbour. 14 And Judah also shall fight at Jerusalem; and the wealth of all the heathen round about shall be gathered together, gold, and silver, and apparel, in great abundance. 15 And so shall be the plague of the horse, of the mule, of the camel, and of the ass, and of all the beasts that shall be in these tents, as this plague. 16 And it shall come to pass, that every one that is left of all the nations which came against Jerusalem shall even go up from year to year to worship the King, the LORD of hosts, and to keep the feast of tabernacles. 17 And it shall be, that whoso will not come up of all the families of the earth unto Jerusalem to worship the King, the LORD of hosts, even upon them shall be no rain. 18 And if the family of Egypt go not up, and come not, that have no rain; there shall be the plague, wherewith the LORD will smite the heathen that come not up to keep the feast of tabernacles. 19 This shall be the punishment of Egypt, and the punishment of all nations that come not up to keep the feast of tabernacles. 20 In that day shall there be upon the bells of the horses, HOLINESS UNTO THE LORD; and the pots in the LORD’S house shall be like the bowls before the altar. 21 Yea, every pot in Jerusalem and in Judah shall be holiness unto the LORD of hosts: and all they that sacrifice shall come and take of them, and seethe therein: and in that day there shall be no more the Canaanite in the house of the LORD of hosts. | {"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": 0.8579097390174866, "perplexity": 4805.316584665571}, "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-2017-26/segments/1498128320215.92/warc/CC-MAIN-20170624031945-20170624051945-00419.warc.gz"} |
https://www.physicsforums.com/threads/calculating-magnetic-field-of-permanent-magnet.87718/ | # Calculating Magnetic field of permanent magnet
1. Sep 6, 2005
### Hobnob
Hi: I'm having real trouble finding resources for the problem of accurately calculating (and drawing the field lines for) a magnetic field around a permanent bar magnet, or between two permanent magnets (I assume this is the same problem, as fields are superposable). I've found lots of sites talking about Maxwell's equations, but nothing about how to relate this to permanent magnets, rather than fields induced by currents. For that matter, I'm a little lost even with Maxwell's equations, as my field calculus is *very* rusty and was never that good to start with... I can't quite see how to move between the path/surface integrals and the actual field at a particular point.
Can anyone point to some good resources for someone who needs a bit of hand-holding but is ultimately up to the task?
All this is ultimately to be part of a motor/generator simulator, so a final question is: can I manage by just pre-calculating the magnetic field and superposing it on the field from the wire, or am I barking up completely the wrong tree?
Thanks
2. Sep 6, 2005
### shyboy
in first approximation the field well outside the magnet is a usual dipole field.
The next step is quite troubling, because you need to take into the account the effect of one part magnet on the magnetization of another part of the magnet. The problem is that you may have hysteresis und saturation. I have now idea how take the hysterisis into the account, but saturation is fine, as soon as you are using a computer.
The problem may be formulated like this:
let's imagine we have a small dipole with a magnetic moment $$M$$. Then, if we put another dipole near it, their magnetic field will be a superposition of two dipoles. But their dipole moments will be affected by the external magnetic field from another dipole. The additional induced magnetic moment will be proportional to the external magnetic field and the dipole's supsceptibility, which may be nonlinear function of the external magnetic field. | {"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": 0.8544325828552246, "perplexity": 400.48109507008274}, "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/1537267162385.83/warc/CC-MAIN-20180925182856-20180925203256-00001.warc.gz"} |
http://math.stackexchange.com/questions/356878/finitely-generated-integral-domain-and-finitely-generated-k-algebra | Finitely generated integral domain and finitely generated $k$-algebra.
Let $k$ be a field and $R$ a finitely generated domain over $k$. Then there are $y_1, \ldots, y_n$ such that $$R=k[y_1, \ldots, y_n]/P,$$ where $P$ is some prime ideal of $k[y_1, \ldots, y_n]$. My question is the following: is $R$ a finitely generated $k$-algebra? It seems that every finitely generated $k$-algebra has the form $k[x_1, \ldots, x_m]$. But $R$ does not have this form. Thank you very much.
-
It is generated by the classes of $y_1,\dotsc,y_n$. Not every finitely generated $k$-algebra is of the form $k[x_1,\dotsc,x_m]$. Since there can be relations between the generators you have to mod them out (this is the $P$ in your definition of $R$). I assume you mean "is isomorphic to" when writing "have this form". – Hans Giebenrath Apr 10 '13 at 7:32
@HansGiebenrath, thank you very much. – LJR Apr 10 '13 at 7:45
A ring $R$ is a $k$-algebra if there is a homomorphism $k \to R$ and it is finitely generated (as a $k$-algebra) if there are elements finitely many $\{x_i\} \subset R$ such that each $r \in R$ can be written as a polynomial of the $x_i$'s with coefficients in $k$.
This is certainly true for a polynomial ring $k[x_1,\cdots, x_n]$, and it is therefore also true for any quotient $R=k[x_1, \cdots,x_n]/I$, since the classes of the $x_i$ generate $R$ as a $k$-algebra. | {"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": 0.9893268942832947, "perplexity": 69.55083808398403}, "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-2015-18/segments/1429246659483.51/warc/CC-MAIN-20150417045739-00280-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://tex.stackexchange.com/questions/284231/alignment-problem-with-enumerate | # Alignment problem with enumerate
This simple table is not working out for me. The first item in the table does not align with the others, see picture. I can not figure out why not. Thank you.
\begin{enumerate}
\begin{tabular}{p{3cm}p{3cm}p{3cm}p{3cm}p{3cm}p{3cm}}
\item c) & \item c) & \item c) & \item a)& \item d) & \item b)
\end{tabular}
\end{enumerate}
• Hi and welcome to TeX.SE. It's usually more helpful to post a complete minimal document rather than a code fragment. (So wrap your code in a \documentclass{article}\begin{document}...\end{document}.) What you're doing here seems like a very odd use of enumeration. (And it's actually amazing that it works at all.) So what exactly do you want to achieve? If you simply want to number cells in a table, there are better ways to do this. If you want an "in-line" enumeration, there are also better ways to do that. Dec 22 '15 at 2:10
A list naturally inserts a spacing between elements, as well as at the start and end of the list. As such, there may be different spacing above the first \item, between each successive \items, and after the last \item. In your example it's better to remove all spacing inserted by the list via the nosep option provided by enumitem:
\documentclass{article}
\usepackage{enumitem,tabularx}
\begin{document}
\begin{enumerate}[nosep]
\begin{tabular}{ *{6}{p{25mm}} }
\item c) & \item c) & \item c) & \item a) & \item d) & \item b)
\end{tabular}
\end{enumerate}
\noindent
\setcounter{enumi}{0}%
\begin{tabularx}{\textwidth}{ *{6}{>{\refstepcounter{enumi}\theenumi.~\ignorespaces}X} }
c) & c) & c) & a) & d) & b)
\end{tabularx}
\end{document}
Another option is proposed at the end, suggesting you use another way of automating the enumeration within a tabular. Specifically, I've used tabularx to ensure that the tabular width doesn't go beyond \textwidth, while \refstepcounter{enumi}\theenumi.~ is inserted at the start of every cell. enumi is the counter associated with enumeration at the root level, so I'm reusing it here.
The former method has some duplication in it, as both \item and & is used to separate an item, while the later obscures the fact that you're building a list. So, perhaps both have their (dis)advantages.
Another method, perhaps more appropriate in this situation, might be to use inline lists; something supported since enumitem V3.0:
\documentclass{article}
\usepackage[inline]{enumitem}
\begin{document}
\begin{enumerate*}[itemjoin=\hfill]
\item c) \item c) \item c) \item a) \item d) \item b)
\end{enumerate*}
\end{document}
You can specify how the items are joined inside an enumerate* - a specific inline enumeration environment. I've used \hfill to stretch content across the text block width.
• But surely this is not an ideal method to achieve this output? Dec 22 '15 at 2:18
• @AlanMunn: It surely isn't. Dec 22 '15 at 2:19
• So then you're encouraging bad practices... Isn't this what the site is trying to avoid. Do I need to downvote you? :) This is a classic XY problem (hence my comment to the OP). Dec 22 '15 at 2:20
• @AlanMunn: Let me clarify. Surely there are better ways of doing it, all depending on the OP's intent. I've added another option for automated listing within (say) tabularx, together with some clarification as to the different methods. I don't think the OP's usage is bad per se, just odd. Dec 22 '15 at 2:28 | {"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": 0.9859709739685059, "perplexity": 1191.3363495769045}, "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/1631780056856.4/warc/CC-MAIN-20210919095911-20210919125911-00472.warc.gz"} |
http://cxc.cfa.harvard.edu/ciao/threads/hrci_bg_spectra/ | # The HRC-I Background Spectra Files
## Overview
#### Synopsis:
The HRC calibration team has released a set of background spectra from the HRC-I. These spectra describe the particle background of the detector and vary slowly with time which means that they can be used to improve the signal-to-noise of HRC-I imaging data. This can significantly improve signal-to-noise for extended sources and may be useful for point source analysis (e.g. fields with many point sources).
#### Purpose:
The intent of this thread is to apply a PI (instrumental energy channel) filter to an HRC-I imaging event file to increase the signal-to-noise of the resulting images by removing channel ranges in which the particle background dominates. Calculating the cumulative source and background PI distributions allow us to estimate the fraction of source and background counts removed by a given PI filter.
To create an HRC-I background event file tailored to a specific observation for imaging or spatial analyses, follow the HRC-I Background Event Files thread instead.
Last Update: 18 Dec 2014 - Reviewed for CIAO 4.7; no changes.
## Get Started
unix% download_chandra_obsid 9700 evt2,asol,bpix,dtf
## Obtain the Response Files: ARF and RMF
This analysis requires an ARF and RMF. This section of the thread provides the necessary commands; refer to the ahelp files for asphist and mkarf for details.
For the HRC-I, a single RMF file distributed in the CALDB is used (rather than an observation specific one as for ACIS). We make a soft link to the file for easier access:
## Compute the cumulative background distribution
The background spectrum is used to estimate the reduction in the background signal that the PI filtering will achieve.
unix% sherpa
-----------------------------------------------------
Welcome to Sherpa: CXC's Modeling and Fitting Package
-----------------------------------------------------
CIAO 4.4 Sherpa version 1 Friday, December 2, 2011
sherpa> d = get_data()
sherpa> pi = d.channel-1.0
sherpa> bgcumul = np.cumsum(d.counts)
sherpa> bgcdf = bgcumul * 1.0 / bgcumul[-1]
sherpa> set_plot_xlabel("PI")
sherpa> set_plot_ylabel(r"\Sigma (counts \leq PI) / \Sigma counts")
sherpa> set_plot_title(d.name.split("/")[-1])
Note that the calculation for bgcdf assumes that d.counts is >= 0, which should be safe here.
## Compute the cumulative distributions for model spectrum
We assume that the source spectrum is unknown, so in order to select the PI range we use a soft and a hard spectrum to determine suitable lower and upper limits. For this thread we use an absorbed power law in both cases, varying the absorption and slope to maximize the relative flux at low or high energies, although other approaches are possible (in particular using a model similar to that of the source).
### Set up an ARF and RMF
We use the background model which we have already loaded to define the channel grid, and add an ARF and RMF to it.
sherpa> load_arf("9700_arf.fits")
sherpa> set_analysis("channel")
The set_analysis call is to ensure that the following modeling is done in PI channels rather than energy or wavelength units.
### Set up the "soft" model
sherpa> set_source(xswabs.abs1*powlaw1d.pl)
sherpa> abs1.NH = 0.001
sherpa> pl.gamma = 2.5
sherpa> plot_model(overplot=False)
The add_window call is used so that the original plot is not deleted by the call to plot_model.
### Calculate the cumulative distribution
sherpa> scumul = np.cumsum(get_model_plot().y)
sherpa> scdf = scumul / max(scumul)
sherpa> current_window("win1")
sherpa> add_curve(pi, scdf, ["symbol.style", "none", "line.color", "red"])
Here we add the cumulative distribution for the soft model to the original plot, so that it can be compared to that of the background spectrum.
### Set up the "hard" model
sherpa> abs1.nh = 10
sherpa> pl.gamma = 1
sherpa> current_window("win2")
sherpa> plot_model(overplot=True)
sherpa> set_histogram(["line.color", "blue"])
### Calculate the cumulative distribution
sherpa> hcumul = np.cumsum(get_model_plot().y)
sherpa> hcdf = hcumul / max(hcumul)
sherpa> current_window("win1")
sherpa> add_curve(pi, hcdf, ["symbol.style", "none", "line.color", "blue"])
## Calculate the PI range
Various strategies could be employed to optimize the PI range. Ideally, we seek to maximize background reduction while minimizing loss of source events. In practice, the trade-off requires testing many different PI ranges and adopting one that suits best. One strategy is to require a certain amount of reduction in background, compute the appropriate PI range, and then estimate the magnitude of source event loss for a specific source model. Alternately, one could set forth an acceptable amount of source loss (sensible ranges are 1 to 10 per cent), compute the appropriate PI range, and then check how much of an improvement results in the background.
This thread follows the latter strategy. We will use a conservative strategy, and look to lose only 5% of source events, split equally over the low and high PI ranges. If xfrac is the fraction of events to exclude and is set to 5%, then we have
sherpa> xfrac = 0.05
sherpa> pimin = np.interp(xfrac/2, scdf, pi)
sherpa> pimax = np.interp(1-xfrac/2, hcdf, pi)
sherpa> lo = int(pimin)
sherpa> hi = int(pimax) + 1
sherpa> print ("PI range: %d to %d" % (lo,hi))
PI range: 47 to 293
Here we chose to round the minimum limit down and the maximum limit up; routines in the Python math module, such as floor and ceil can be used to implement different rounding strategies.
The lo to hi range can then be used to filter the level=2 event file when creating images.
## Calculating the background reduction
The PI range can be viewed by saying:
sherpa> current_window("win1")
and the fraction of the background that is excluded by these limits is calculated by:
sherpa> blo = np.interp(lo, pi, bgcdf)
sherpa> bhi = 1.0 - np.interp(hi, pi, bgcdf)
sherpa> bfrac = bhi + blo
sherpa> print("Fraction of background excluded is %g" % bfrac)
Fraction of background excluded is 0.242981
Filtering on the range PI=48:293 will reduce the background by ~25% while only losing ~5% of x-ray events.
## Apply the PI Filter
The PI range 48:293 is applied to the file in a Data Model filter:
unix% punlearn dmcopy
unix% dmcopy "hrcf09700N003_evt2.fits[pi=48:293]" hrcf09700_evt2_pi_flt.fits
A background annulus is defined around the source to check the number of "good" events in the filtered and unfiltered files:
unix% cat bkg.reg
# Region file format: CIAO version 1.0
annulus(16368.483,16336.472,2731.4111,4097.1167)
unix% dmstat "hrcf09700N003_evt2.fits[sky=region(bkg.reg)][cols pi]" ver=0
unix% pget dmstat out_good
54713
unix% dmstat "hrcf09700_evt2_pi_flt.fits[sky=region(bkg.reg)][cols pi]" ver=0
unix% pget dmstat out_good
42567
The percent change between the files is ~22% [(54713-42567)/54713 = 22], which is close to the 24% reduction we expected.
## Scripting It
The file hrci.shp performs the Sherpa commands used in this thread. One could loop over different values of xfrac to find the optimal S/N improvement.
## History
10 Jun 2010 new for CIAO 4.2/CALDB 4.3.0 11 Jan 2011 reviewed for CIAO 4.3: no changes 04 Apr 2011 updated for 04 Apr scripts package release: hrc_bkgrnd_lookup script prints the version at verbose > 0. 20 Jul 2011 required software updates are listed in Synopsis 11 Jan 2012 reviewed for CIAO 4.4 and CALDB 4.4.7: the 2010 HRC-I background PI spectrum file was remade with the new gain map (hrciD2010-09-25pibgspecN0001.fits), and the 2011 file has been added (hrciD2011-09-19pibgspecN0001.fits); added Scripting It section 03 Dec 2012 Review for CIAO 4.5; file version name changes 03 Dec 2013 Review for CIAO 4.6; no changes. 14 Apr 2014 Minor edits to text to clarify when/how to use this thread. Updated list of CALDB files. 18 Dec 2014 Reviewed for CIAO 4.7; no changes. | {"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": 0.7590901255607605, "perplexity": 6162.985974962522}, "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-2017-22/segments/1495463610342.84/warc/CC-MAIN-20170528162023-20170528182023-00321.warc.gz"} |
https://www.conwaylife.com/forums/viewtopic.php?p=66857 | ## Catagolue Oddities
For general discussion about Conway's Game of Life.
muzik
Posts: 3850
Joined: January 28th, 2016, 2:47 pm
Location: Scotland
### Re: Catagolue Oddities
EDIT: both amended
Seems as though haul/ pages need updating, only the square symmetries are being listed here:
https://catagolue.appspot.com/haul/b2s3h/
Also, the new symmetries are being interpreted as unofficial:
https://catagolue.appspot.com/census/b2s3h/
Last edited by muzik on December 21st, 2018, 6:45 am, edited 1 time in total.
Bored of using the Moore neighbourhood for everything? Introducing the Range-2 von Neumann isotropic non-totalistic rulespace!
muzik
Posts: 3850
Joined: January 28th, 2016, 2:47 pm
Location: Scotland
### Re: Catagolue Oddities
Some Life patterns seem to have weirdly formatted names; for example compare
https://catagolue.appspot.com/object/xp2_31egge13/b3s23
to
https://catagolue.appspot.com/object/xp ... a221/b3s23
Shouldn't the latter be called "tub test-tube baby" instead?
Bored of using the Moore neighbourhood for everything? Introducing the Range-2 von Neumann isotropic non-totalistic rulespace!
dani
Posts: 1004
Joined: October 27th, 2017, 3:43 pm
Location: New Jersey, USA
Contact:
### Re: Catagolue Oddities
I always found that weird since 'tubebaby' isn't a word...
she/her
moose#0915
calcyman
Posts: 2227
Joined: June 1st, 2009, 4:32 pm
### Re: Catagolue Oddities
danny wrote:I always found that weird since 'tubebaby' isn't a word...
Same here. The 'common names' mapping is a complete mess, and no-one has had time to go through all 3621 lines of it to ensure consistency. I think the 'tubebaby' slipped in from Achim's census:
http://wwwhomes.uni-bielefeld.de/achim/ ... _life.html
Potentially the common names mapping could be automatically updated from the object pages on LifeWiki, if there's an API to download this data?
What do you do with ill crystallographers? Take them to the mono-clinic!
calcyman
Posts: 2227
Joined: June 1st, 2009, 4:32 pm
### Re: Catagolue Oddities
I previously wrote:Potentially the common names mapping could be automatically updated from the object pages on LifeWiki, if there's an API to download this data?
I've figured out how to do this from the command-line using curl:
Code: Select all
$curl http://conwaylife.com/wiki/Pond_on_dock?action=edit 2>/dev/null | grep '^|.*=' |name = Pond on dock |pname = pondanddock |c = 18 |bx = 8 |by = 6 |rulemin = B/S23 |rulemax = B3678/S012345678 |rulespecial = [[Conway's Game of Life|Conway Life]] |rle = true |apgcode = xs18_3lk453z3443 |niemiecid = 18.2387 |pentadecathlonid = 18.2654 |viewerconfig = #C [[ GPS 2 THUMBSIZE 2 ]] Would anyone (@Nathaniel, @AppleBottom, @dvgrn) be vehemently opposed to me running over a thousand GET requests to LifeWiki to obtain a more comprehensive 'common names' list for use in Catagolue? One appealing aspect is that the 'common names' list could also store auxiliary information, including links from the Catagolue object pages back to the LifeWiki. What do you do with ill crystallographers? Take them to the mono-clinic! muzik Posts: 3850 Joined: January 28th, 2016, 2:47 pm Location: Scotland ### Re: Catagolue Oddities calcyman wrote: I previously wrote:Potentially the common names mapping could be automatically updated from the object pages on LifeWiki, if there's an API to download this data? I've figured out how to do this from the command-line using curl: Code: Select all $ curl http://conwaylife.com/wiki/Pond_on_dock?action=edit 2>/dev/null | grep '^|.*='
|name = Pond on dock
|pname = pondanddock
|c = 18
|bx = 8
|by = 6
|rulemin = B/S23
|rulemax = B3678/S012345678
|rulespecial = [[Conway's Game of Life|Conway Life]]
|rle = true
|apgcode = xs18_3lk453z3443
|niemiecid = 18.2387
|viewerconfig = #C [[ GPS 2 THUMBSIZE 2 ]]
Would anyone (@Nathaniel, @AppleBottom, @dvgrn) be vehemently opposed to me running over a thousand GET requests to LifeWiki to obtain a more comprehensive 'common names' list for use in Catagolue?
One appealing aspect is that the 'common names' list could also store auxiliary information, including links from the Catagolue object pages back to the LifeWiki.
Currently we're trying to reach a consensus on the wiki for pattern naming, which might take a while, so that we can have a cleaner, more consistent methodology for systematically naming still lifes and oscillators, which should eventually carry on to Catagolue. (You're welcome to join in by the way.)
Bored of using the Moore neighbourhood for everything? Introducing the Range-2 von Neumann isotropic non-totalistic rulespace!
calcyman
Posts: 2227
Joined: June 1st, 2009, 4:32 pm
### Re: Catagolue Oddities
calcyman wrote:One appealing aspect is that the 'common names' list could also store auxiliary information, including links from the Catagolue object pages back to the LifeWiki.
I decided to do this anyway. Take a look at xs12, for instance:
https://catagolue.appspot.com/census/b3s23/C1/xs12
The H2 titles of the object pages are similarly updated:
https://catagolue.appspot.com/object/xq ... 1032/b3s23
It makes Catagolue and LifeWiki feel more tightly coupled; their object pages link seamlessly (I hope!) in both directions.
Here you can see which objects are on the LifeWiki (common names have hyperlinks), which ones have common names from elsewhere (no hyperlinks), and which ones have no common name (apgcode only). I imagine this could be useful for LifeWiki maintainers.
muzik wrote:Currently we're trying to reach a consensus on the wiki for pattern naming, which might take a while, so that we can have a cleaner, more consistent methodology for systematically naming still lifes and oscillators, which should eventually carry on to Catagolue. (You're welcome to join in by the way.)
Great! When that's been accomplished, I can just rerun the scripts to scrape LW and generate an updated common names list.
What do you do with ill crystallographers? Take them to the mono-clinic!
mniemiec
Posts: 1122
Joined: June 1st, 2013, 12:00 am
### Re: Catagolue Oddities
calcyman wrote:I decided to do this anyway. Take a look at xs12, for instance: ...
This looks very nice! One thing that concerns me, however, is that Catagolue seems to sort object by APG, irrespective of rule; e.g. comments appear to be shared by patterns in different rules that share the same APG code, even if the patterns don't behave the same way. This isn't an issue with still-lifes (which DO behave the same way), but oscillators and spaceships often have different behaviors in different phases, and spaceships may even have different velocities, but they're lumped in together as long as they share the same period.
Apple Bottom
Posts: 1033
Joined: July 27th, 2015, 2:06 pm
Contact:
### Re: Catagolue Oddities
calcyman wrote:Would anyone (@Nathaniel, @AppleBottom, @dvgrn) be vehemently opposed to me running over a thousand GET requests to LifeWiki to obtain a more comprehensive 'common names' list for use in Catagolue?
Certainly not me --- only Nathaniel can say for sure, since he's the one ultimately running the server, but MediaWiki is made for handling lots of page views; it's got rather sophisticated caching, so reads are cheap.
Since you're a Python aficionado, BTW, there's a an actively-maintained Python wrapper around the MediaWiki API, pymediawiki. Chances are you've already discovered it, but I thought I'd toss the link out here anyway. There's also a tool for generating backups of MediaWiki installations that you could use to all current page versions, if you like dealing with XML.
EDIT: ah, I see you've already gone ahead. Good stuff, it's nice to see the various sites in the Life universe being woven together more tightly.
If you speak, your speech must be better than your silence would have been. — Arabian proverb
Catagolue: Apple Bottom • Life Wiki: Apple Bottom • Twitter: @_AppleBottom_
Proud member of the Pattern Raiders!
PushDecimal
Posts: 17
Joined: November 21st, 2018, 4:23 pm
### Re: Catagolue Oddities
Two distant spaceships being recognised as one:
http://catagolue.appspot.com/census/b3-es23/C1/xq14
Ian07
Posts: 563
Joined: September 22nd, 2018, 8:48 am
### Re: Catagolue Oddities
The × character used on the wiki shows up incorrectly on Catagolue:
https://catagolue.appspot.com/object/xs ... 6221/b3s23
77topaz
Posts: 1497
Joined: January 12th, 2018, 9:19 pm
### Re: Catagolue Oddities
I just noticed an enormous pile of submitted but unverified/uncommitted hauls sitting in the b3s23/C1 census backlog. The weird thing is that, despite this backlog, apgsearch's /verify function claims there are no more hauls to verify. What's up with that?
Ian07
Posts: 563
Joined: September 22nd, 2018, 8:48 am
### Re: Catagolue Oddities
77topaz wrote:I just noticed an enormous pile of submitted but unverified/uncommitted hauls sitting in the b3s23/C1 census backlog. The weird thing is that, despite this backlog, apgsearch's /verify function claims there are no more hauls to verify. What's up with that?
Initially, I thought this had something to do with peer review automatically being enabled for censuses with over 10^12 objects, but Adam told me it was actually an error caused by someone searching Day & Night. The error's now been fixed, and I'm currently working on verifying the backlog of hauls this caused.
77topaz
Posts: 1497
Joined: January 12th, 2018, 9:19 pm
### Re: Catagolue Oddities
The strange thing is that my apgsearch keeps saying "No more hauls to verify." even when there are clearly still many hauls in the "?committed=0" log. This didn't happen, for example, when rliston was submitting many b3s23/C1 hauls quickly; those just verified normally and that backlog was eventually cleared when I edited my apgsearch to essentially work as a full-time verification script. But this approach isn't working for me now, because apgsearch isn't even recognising that this backlog of hauls needs to be verified.
calcyman
Posts: 2227
Joined: June 1st, 2009, 4:32 pm
### Re: Catagolue Oddities
77topaz wrote:The strange thing is that my apgsearch keeps saying "No more hauls to verify." even when there are clearly still many hauls in the "?committed=0" log. This didn't happen, for example, when rliston was submitting many b3s23/C1 hauls quickly; those just verified normally and that backlog was eventually cleared when I edited my apgsearch to essentially work as a full-time verification script. But this approach isn't working for me now, because apgsearch isn't even recognising that this backlog of hauls needs to be verified.
The ones awaiting verification are in 'committed=1'. The system is:
• Hauls received from apgsearch immediately have committed=0;
• The cron process moves them to either committed=1 (if verification is enabled) or commits them immediately (if verification is disabled);
• Instances of apgsearch verify hauls in the committed=1 group, moving them to either committed=3 (successful) or committed=4 (unsuccessful);
• If verification is enabled, the cron process commits anything with committed=3 (moving them to committed=2).
At the moment Catagolue seems to be committing the maximum allowed rate of 120 hauls every cron process (i.e. every 12 minutes), so it should soon catch up with the backlog.
What do you do with ill crystallographers? Take them to the mono-clinic!
77topaz
Posts: 1497
Joined: January 12th, 2018, 9:19 pm
### Re: Catagolue Oddities
For range-1 Generations rules, a LifeViewer is rendered if the pattern has no state-2+ cells in its canonical phase (example), but only a static image is shown otherwise (example). It's a bit weird, because both of these examples are in the same rule and both have a functional apgcode, yet one has a LifeViewer and one does not.
Also, I think hexagonal-neighbourhood rules should perhaps have a separate rule folder from the Moore-neighbourhood non-totalistic rules. (EDIT: This was done within a few minutes of this post being written.)
EDIT: The transcluded-information-from-Fano boxes for outer-totalistic rules seem to have disappeared.
muzik
Posts: 3850
Joined: January 28th, 2016, 2:47 pm
Location: Scotland
### Re: Catagolue Oddities
77topaz wrote:EDIT: The transcluded-information-from-Fano boxes for outer-totalistic rules seem to have disappeared.
Is it just me, or is fano also timing out every time I try to connect to it?
Another oddity: the site says that you should select a symmetry type for a rule even when said rule hasn't yet been searched. https://catagolue.appspot.com/census/bs1234567
Bored of using the Moore neighbourhood for everything? Introducing the Range-2 von Neumann isotropic non-totalistic rulespace!
muzik
Posts: 3850
Joined: January 28th, 2016, 2:47 pm
Location: Scotland
### Re: Catagolue Oddities
Rather problematic oddity: this list page
https://catagolue.appspot.com/rules/isotropic
houses a particularly long rulestring which results in the table being unnaturally stretched. The end result is that all named rules, as well as numbers of censuses, all of which are written in black text, end up being ousted from the light background onto the dark background, making them particularly hard to read.
There are a few ways to fix this problem;
- All rules with non-canonical rulestrings could be removed from this table (and tabulated elsewhere; there are likely many rules of interest which have not yet been searched under a canonical rulestring), which would help keep the table at a reasonable size; the maximum permittable length of a rulestring would probably not cause such dramatic stretching.
- A script could be run that automatically renames/merges all censuses from their noncanonical forms into their canonical forms, also eliminating this problem and cleaning up the site as well as a result.
Bored of using the Moore neighbourhood for everything? Introducing the Range-2 von Neumann isotropic non-totalistic rulespace!
dani
Posts: 1004
Joined: October 27th, 2017, 3:43 pm
Location: New Jersey, USA
Contact:
### Re: Catagolue Oddities
or just delete the rule
she/her
moose#0915
A for awesome
Posts: 2063
Joined: September 13th, 2014, 5:36 pm
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### Re: Catagolue Oddities
Or abbreviate (/ellipticize [is that a word]) the offending rules, or just wrap them at a certain character length. Either of those could be useful for apgcodes as well — I'd personally lean toward wrapping the rules at about 60 characters and apgcodes at some other value appropriate to the formatting (but I'm not @calcyman, so it's really just a thought).
x₁=ηx
V ⃰_η=c²√(Λη)
K=(Λu²)/2
Pₐ=1−1/(∫^∞_t₀(p(t)ˡ⁽ᵗ⁾)dt)
$$x_1=\eta x$$
$$V^*_\eta=c^2\sqrt{\Lambda\eta}$$
$$K=\frac{\Lambda u^2}2$$
$$P_a=1-\frac1{\int^\infty_{t_0}p(t)^{l(t)}dt}$$
http://conwaylife.com/wiki/A_for_all
Aidan F. Pierce
muzik
Posts: 3850
Joined: January 28th, 2016, 2:47 pm
Location: Scotland
### Re: Catagolue Oddities
Those would also work, but then that results in a lot of duplicate rules remaining in the list, taking up space, which isn't ideal.
-
It seems that for outer-totalistic and isotropic non-totalistic rules, catagolue only checks if p99 and below patterns make sense:
https://catagolue.appspot.com/object/xq ... 6952/b3s23
https://catagolue.appspot.com/object/xq ... 6952/b3s23
Other rulespaces (including B0) don't seem to care:
https://catagolue.appspot.com/object/xq ... b0235s1234
https://catagolue.appspot.com/object/xq ... b0235s1234
Bored of using the Moore neighbourhood for everything? Introducing the Range-2 von Neumann isotropic non-totalistic rulespace!
77topaz
Posts: 1497
Joined: January 12th, 2018, 9:19 pm
### Re: Catagolue Oddities
That limit is because if the server had to double-check a large amount of generations each time someone wanted to load a pattern page (the xp apgcodes can go up to 1048576), it would slow the site down and possibly also strain the server quota.
muzik
Posts: 3850
Joined: January 28th, 2016, 2:47 pm
Location: Scotland
### Re: Catagolue Oddities
Isn't it because only period 100 and up patterns are actually simulated in image form?
Bored of using the Moore neighbourhood for everything? Introducing the Range-2 von Neumann isotropic non-totalistic rulespace!
77topaz
Posts: 1497
Joined: January 12th, 2018, 9:19 pm
### Re: Catagolue Oddities
Those are both for the same reason: preventing server lag/strain. And having an invalid apgcode does not prevent apgsearch from simulating a GIF for it in a census, even if the period is below 100.
muzik
Posts: 3850
Joined: January 28th, 2016, 2:47 pm
Location: Scotland
### Re: Catagolue Oddities
77topaz wrote:For range-1 Generations rules, a LifeViewer is rendered if the pattern has no state-2+ cells in its canonical phase (example), but only a static image is shown otherwise (example). It's a bit weird, because both of these examples are in the same rule and both have a functional apgcode, yet one has a LifeViewer and one does not.
In addition, LifeViewer doesn't follow the same colour scheme as the previewed pattern image files. There are no green cells to be seen in the evolution of this:
https://catagolue.appspot.com/object/xp13_318c/g13b3s23
-
The isotropic non totalistic rules page seems to have its stretching fixed, although the non-canonical rules are still there...
Bored of using the Moore neighbourhood for everything? Introducing the Range-2 von Neumann isotropic non-totalistic rulespace! | {"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": 0.5423009991645813, "perplexity": 7637.428142870586}, "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/1593655896169.35/warc/CC-MAIN-20200708000016-20200708030016-00049.warc.gz"} |
https://usa.cheenta.com/triangle-and-integers-aime-i-1995-question-9/ | Categories
# Triangle and integers | AIME I, 1995 | Question 9
Try this beautiful problem from the American Invitational Mathematics Examination I, AIME I, 1995 based on Triangle and integers.
Try this beautiful problem from the American Invitational Mathematics Examination I, AIME I, 1995 based on Triangle and integers.
## Triangle and integers – AIME I, 1995
Triangle ABC is isosceles, with AB=AC and altitude AM=11, suppose that there is a point D on AM with AD=10 and $\angle BDC$=3$\angle BAC$. then the perimeter of $\Delta ABC$ may be written in the form $a+\sqrt{b}$ where a and b are integers, find a+b.
• is 107
• is 616
• is 840
• cannot be determined from the given information
### Key Concepts
Integers
Triangle
Trigonometry
AIME I, 1995, Question 9
Plane Trigonometry by Loney
## Try with Hints
Let x= $\angle CAM$
$\Rightarrow \angle CDM =3x$
$\Rightarrow \frac{tan3x}{tanx}=\frac{\frac{CM}{1}}{\frac{CM}{11}}$=11 [by trigonometry ratio property in right angled triangle]
$\Rightarrow \frac{3tanx-tan^{3}x}{1-3tan^{2}x}=11tanx$
solving we get, tanx=$\frac{1}{2}$
$\Rightarrow CM=\frac{11}{2}$
$\Rightarrow 2(AC+CM)$ where $AC=\frac{11\sqrt {5}}{2}$ by Pythagoras formula
=$\sqrt{605}+11$ then a+b=605+11=616. | {"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": 0.4328649044036865, "perplexity": 5432.227379663726}, "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-2020-50/segments/1606141203418.47/warc/CC-MAIN-20201129214615-20201130004615-00455.warc.gz"} |
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Subject: Re: [virtio-comment] [PATCH RFC] virtio: introduce VIRTIO_F_DEVICE_STOP
• From: Halil Pasic <pasic@linux.ibm.com>
• To: Jason Wang <jasowang@redhat.com>
• Date: Mon, 21 Dec 2020 22:33:38 +0100
On Fri, 18 Dec 2020 12:23:02 +0800
Jason Wang <jasowang@redhat.com> wrote:
> This patch introduces a new status bit DEVICE_STOPPED. This will be
> used by the driver to stop and resume a device. The main user will be
> live migration support for virtio device.
>
Can you please provide some more background information, or point
me to the appropriate discussion?
I mean AFAIK migration already works without this driver initiated
drain. What is the exact motivation? What about the big picture? I
guess some agent in the guest would have to make the driver issue
the DEVICE_STOP.
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> content.tex | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/content.tex b/content.tex
> index 61eab41..4392b60 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -47,6 +47,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
> \item[DRIVER_OK (4)] Indicates that the driver is set up and ready to
> drive the device.
>
> +\item[DEVICE_STOPPED (32)] When VIRTIO_F_DEVICE_STOPPED is negotiated,
> + indicates that the device has been stopped by the driver.
> +
AFAIU it is not only about indicating stopped, but also requesting to be
stopped.
More importantly, that must not be set immediately, in a sense that the
one side initiates some action by requesting the bit to be set, and the
other side must not set the bit before the action is performed. We also
seem to assume that every device implementation is capable of performing
this trick. Is it for hardware devices (e.g. PCI) standard to request an
operation by writing some value into a register, and get feedback bout
completion, by reading the same value as written?
> \item[DEVICE_NEEDS_RESET (64)] Indicates that the device has experienced
> an error from which it can't recover.
> \end{description}
> @@ -58,8 +61,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
> \ref{sec:General Initialization And Device Operation / Device
> Initialization}.
> The driver MUST NOT clear a
> -\field{device status} bit. If the driver sets the FAILED bit,
> -the driver MUST later reset the device before attempting to re-initialize.
> +\field{device status} bit other than DEVICE_STOPPED. If the
> +driver sets the FAILED bit, the driver MUST later reset the device
> +before attempting to re-initialize.
>
> The driver SHOULD NOT rely on completion of operations of a
> device if DEVICE_NEEDS_RESET is set.
> @@ -70,12 +74,28 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev
> recover by issuing a reset.
> \end{note}
>
> +The driver MUST NOT set or clear DEVICE_STOPPED when DRIVER_OK is not
> +set. In order to stop the device, the driver MUST set DEVICE_STOPPED
> +first and re-read status to check whether DEVICE_STOPPED is set by the
> +device. In order to resume the device, the driver MUST clear
> +DEVICE_STOPPED first and read status to ensure whether DEVICE_STOPPED
> +is cleared by the device.
> +
> \devicenormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field}
> The device MUST initialize \field{device status} to 0 upon reset.
>
> The device MUST NOT consume buffers or send any used buffer
> notifications to the driver before DRIVER_OK.
>
> +The device MUST ignore DEVICE_STOPPED when DRIVER_OK is not set.
> +
> +When driver is trying to set DEVICE_STOPPED, the device MUST not
The when driver trying to set DEVICE_STOPPED is a bit soft as a
duration. For example consider virtio-ccw, at the moment when the driver
issues the ssch to set status, the device still does not know about it.
> +process new avail requests and MUST complete all requests that is
> +currently processing before setting DEVICE_STOPPED.
I would like to have a more precise definition of 'new avail requests'
and 'requests that is currently processing'.
> +
> +The device MUST keep the config space unchanged when DEVICE_STOPPED is
> +set.
Here you have the set by driver which is actually requesting the stop
operation, and set by device which indicted that the stop operation
was successfully performed by the device.
> +
> \label{sec:Basic Facilities of a Virtio Device / Device Status Field / DEVICENEEDSRESET}The device SHOULD set DEVICE_NEEDS_RESET when it enters an error state
> that a reset is needed. If DRIVER_OK is set, after it sets DEVICE_NEEDS_RESET, the device
> MUST send a device configuration change notification to the driver.
> @@ -6553,6 +6573,8 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits} | {"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": 0.5187242031097412, "perplexity": 24571.062862086994}, "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/1618038072175.30/warc/CC-MAIN-20210413062409-20210413092409-00158.warc.gz"} |