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http://physics.stackexchange.com/questions/36328/magnetic-paradox-in-relativity | Let 2 electrons A and B be moving parallel with constant velocity $c/10$ in (near) vacuum without a strong gravity field (where $c$ is speed-of-light).
A and B create an electromagnetic field that is proportional to their speed. But then observer A measures ( approx ) the speed of both A and B , and likewise observer B measures ( approx ) the speed of both A and B.
A and B influence each other because of the electromagnetic field differently then if they stood still.
Assuming I made no mistake there , does this not violate relativity since :
1. The laws of physics are the same for all observers in uniform motion relative to one another (principle of relativity).
2. The speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the source of the light.
Where did I go wrong? Do the electrons move each other due to the field and does that make me loose the notion of uniform motion relative to one another so that the law does not apply? Or was i wrong about the dependency with speed upon magnetism and electricity ( and right hand rule ) if one uses a time-dilation correction?
In my question I picked $c/10$ to avoid very strong relativistic effects (as with $c/2$) so that classical electromagnetism is still quite good.
I'm confused here.
How to explain this apparent paradox?
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## migrated from math.stackexchange.comSep 13 '12 at 14:36
This question came from our site for people studying math at any level and professionals in related fields.
This needs to be migrated to physics stack exchange – Larry Harson Sep 13 '12 at 13:20
Are observers A and B the electrons? If not, please do not reuse symbols. If so, neither one sees a relative velocity, so they are in the same frame. – Ross Millikan Sep 13 '12 at 13:24
This should be on physics.SE, but here goes:
In the lab frame, each electron moves in the other electron's magnetic field, which creates a magnetic attraction between them. Thus, they will be seen to move away from each other slower than their Coulomb repulsion would dictate. (Note, incidentally, that the "Coulomb replusion" wouldn't be the entire story anyway -- the instantaneous electric field of a moving charge differs from the field of a stationary charge at the same place).
In the (initial) rest frame of the electrons, there is no magnetic force, only the Coulomb repulsion, so the electrons move away from each other faster than in the lab frame.
How to reconcile those two computations? Relativistic time dilation comes to the rescue -- the slow separation we see in the lab frame is exactly the fast rest-frame separation, slowed down by the relativistic gamma factor.
Lesson to take home: The net force on each electron is not invariant between frames of reference -- but the entire electomagnetic theory gives consistent answers about the actual movement of charges when calculations are done in different inertial frames.
By the way, note that classical electromagnetism is not only "still quite good"; it fits perfectly across all speeds up to $c$, since it happens to be invariant under Lorentz transformations (provided that the fields are transformed accordingly) even though it was formulated before relativity.
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Ignore magnetism and consider only electrostatitics. In fact, electromagnetism is a relativistic effect. In fact, consider two parallel wires. From the static protons there seems to be no net charge, but the moving electrons view different proton and electron densities and therefore "feel" electrostatic force.
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You need to understand that due to relativistic effect from ground frame the charges will experience a greater electric force than when they are at rest. Then they also experience a magnetic force. Add both, it will be equal to Coulomb's force when charges are at rest, as seen from charge frame.
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http://math453fall2008.wikidot.com/chapter-4 | Chapter 4 is all about determining which numbers modulo p (where p is an odd prime) are actually squares of other numbers modulo p. This culminates in Gauss's amazing Law of Quadratic Reciprocity.
In today's class we began by talking about quadratic residues once again. We noticed that we could list the quadratic residues by squaring the first $\frac{p-1}{2}$ residues mod p, and that there were an equal number of quadratic residues and nonresidues. We then introduced the Legendre symbol $\left(\frac{a}{p}\right)$ as the "square indicator function modulo p". Finally we discussed Euler's Criterion for evaluating the Legendre symbol $\left(\frac{a}{p}\right)$ and a few of its consequences. | {"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": 0.8456358909606934, "perplexity": 312.4707506910264}, "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/1498128321426.45/warc/CC-MAIN-20170627134151-20170627154151-00301.warc.gz"} |
http://proceedings.mlr.press/v31/nguyen13a.html | # Competing with an Infinite Set of Models in Reinforcement Learning
Phuong Nguyen, Odalric-Ambrym Maillard, Daniil Ryabko, Ronald Ortner ;
Proceedings of the Sixteenth International Conference on Artificial Intelligence and Statistics, PMLR 31:463-471, 2013.
#### Abstract
We consider a reinforcement learning setting where the learner also has to deal with the problem of finding a suitable state-representation function from a given set of models. This has to be done while interacting with the environment in an online fashion (no resets), and the goal is to have small regret with respect to any Markov model in the set. For this setting, recently the BLB algorithm has been proposed, which achieves regret of order T^2/3, provided that the given set of models is finite. Our first contribution is to extend this result to a countably infinite set of models. Moreover, the BLB regret bound suffers from an additive term that can be exponential in the diameter of the MDP involved, since the diameter has to be guessed. The algorithm we propose avoids guessing the diameter, thus improving the regret bound. | {"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": 0.9306047558784485, "perplexity": 444.51016235398737}, "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-2020-29/segments/1593655887046.62/warc/CC-MAIN-20200705055259-20200705085259-00450.warc.gz"} |
https://www.physicsforums.com/threads/tatp-dadp-density-diffrrences.711806/ | 1. ### zker666
1
I have recently been experimenting with triacetone triperoxide (tatp), and I have been storing it under water since that is the only way it is stable. However, I have noticed that most of the powder suspended in water is clearly denser than the water, and about a fifth of it is floating on top of the water. I am guessing that the process to make the tatp yields some of the dimer form of the AP, which is about 148.157g/mol, which is slightly less than 1g/cm3 which would explain it floating on the water, whereas the trimer of AP is about 222.24g/mol, which would make it denser than 1g/cm3, thus causing it to sink. I am curious about this because the dimer is way more unstable than the trimer, and could be worth skimming the dadp off of the top and storing it separately, and do some small scale testing and comparing the friction, heat, and shock sensitivity of each. Input would be greatly appreciated! :) -Zak
### Staff: Mentor
1. We don't discuss explosives here.
2. I am not aware of any sure way of converting molar masses to densities, so I don't see where your numbers come from. But it is a moot in the light of the point 1.
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http://marcofrasca.wordpress.com/2009/10/30/ | ## Running coupling in QCD
30/10/2009
For a quantum field theory it is essential to know the form of the beta function. The reason for this is that this function gives us immediately an understanding on how the theory will behave in different regimes of the energy range. Currently, there is a lot of activity to obtain the full beta function of QCD, the theory of quarks and gluons. The reason for this is that we want to understand the behavior of this theory when the energy becomes lower while we know that at higher energy asymptotic freedom sets in moving the coupling toward zero so that perturbation theory applies. QCD appears as the perfect theory. Indeed, in this case we have no Landau pole or, possibly, no triviality at lower energies and so this appears as the only example in physics of a theory that holds on the full range of energy. I have read three papers about this matter recently (see here, here and here) and all of them give a clear insight about the question of the beta function for Yang-Mills theory and QCD. As my readers know, lattice computations for a pure Yang-Mills theory show clearly that the running coupling goes to zero at lower energies so one may ask if the same can happen when quarks are involved.
Running coupling from lattice computations
From supersymmetric QCD it has been shown that the beta function should have the form
$\beta(g)=-\frac{g^3}{16\pi^2}\frac{\beta_0+N_f\gamma(g^2)}{1-\frac{Cg^2}{8\pi^2}}$
where, apart for some costants here and there, $N_f$ is the number of quark flavors. So, we immediately realize that supersymmetric QCD can develop a fixed point in the infrared limit even if supersymmetric Yang-Mills theory has none! Sannino and Ryttov have been inspired by this beautiful result and proposed a similar beta function for ordinary QCD and the conclusion is the same: Even if Yang-Mills theory has no fixed point in the infrared, QCD has one due to the presence of quarks. So far, lattice computations for fully QCD confirm this scenario and we can be confident that this theory is the most beautiful one being meaningful for all the energy range.
I would like to add a final comment by noting that Ryttov and Sannino give for Yang-Mills theory in the infrared the same functional form I have got in my latest paper (see here) and that agrees with lattice results. The picture of low-energy QCD is slowly emerging providing to us quite unexpected results and a deeper comprehension of the world as we perceive it.
## Higgs mechanism is essential
30/10/2009
As the readers of my blog know, I have developed, in a series of papers, the way to manage massive solutions out of massless theories, both in classical and quantum cases. You can check my latest preprints here and here. To have an idea, if we consider an equation
$\Box\phi+\lambda\phi^3=0$
then a solution is
$\phi(x)=\mu\left(\frac{2}{\lambda}\right)^\frac{1}{4}{\rm sn}(p\cdot x+\theta,i)$
provided
$p^2=\mu^2\left(\frac{\lambda}{2}\right)^\frac{1}{2}$
being $\mu$ and $\theta$ two arbitrary constants and $\rm sn$ a Jacobi elliptical function. We see that a massless theory has massive solutions arising just from a strong nonlinearity into the equation of motion. The question one may ask is: Does this mechanism work to give mass to particles in the Standard Model? The answer is no and this can already be seen at a classical level. To show this, let us consider the following Yukawa model
$L=\bar{\psi}(i\gamma\cdot\partial-g\phi)\psi+\frac{1}{2}(\partial\phi)^2-\frac{\lambda}{4}\phi^4$
being $g$ a Yukawa coupling. Assuming $\lambda$ very large, one is reduced to the solution of the following Dirac equation that holds at the leading order
$\left(i\gamma\cdot\partial-g\mu\left(\frac{2}{\lambda}\right)^\frac{1}{4}{\rm sn}(p\cdot x+\theta,i)\right)\psi=0$
and this equation is exactly solved in a closed form, provided the fermion has exactly the same mass of the boson, that is $g=\sqrt{\lambda/2}$. So, we see that the massless fermion acquires mass too but it must be degenerate with respect to the bosonic field. This would imply that one needs a different scalar field for each fermion and such bosons would have the same masses of the fermions. This is exactly what happens in a supersymmetric theory but the theory we are considering is not. So, it would be interesting to reconsider all this with supersymmetry, surely something to do in the near future.
This means that Higgs mechanism is essential yet in the Standard Model to understand how to achieve a finite mass for all particles in the theory. We will see in the future what Nature reserved us about. | {"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": 13, "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": 0.9334988594055176, "perplexity": 270.1328214989518}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-20/segments/1368704933573/warc/CC-MAIN-20130516114853-00050-ip-10-60-113-184.ec2.internal.warc.gz"} |
https://myassignments-help.com/2022/12/07/financial-derivatives-dai-xie-fina5220-2/ | # 金融代写|金融衍生品代写Financial derivatives代考|FINA5220
## 金融代写|金融衍生品代写Financial derivatives代考|Overnight Indexed Swap
An overnight indexed swap (OIS) is an interest rate swap where the cash-flow of the floating leg is based on a floating rate calculated from the overnight rates such as Eonia or effective fed funds rate for the concerned period.
Consider the example of Eonia which is quoted on ACT/360. The floating rate for OIS of the $k$-th period $\left(t_{k-1}, t_k\right)$ will be calculated as the geometric average of Eonia fixings:
$$R_k=\left[\prod_{i=1}^{N_{f i x}^k}\left(1+\frac{r_i \times n_i}{360}\right)-1\right] \frac{360}{N_k},$$
where
$R_k$ : rate for OIS of the $k$-th period
$N_{f i x}^k$ : total number of fixings of the overnight rate for the $k$-th period
$r_i$ : Eonia fixing rate for day $i$
$n_i$ : number of calendar days covered by $r_i$
$N_k$ : total number of calendar days for the $k$-th period
The rate of OIS implies less risk than the corresponding interbank lending rate such as Libor and Euribor because OIS rate is based on actual trades, which makes it more difficult to be manipulated.
Because of counterparty risk, the derivatives trades are normally collateralized. The cash collaterals are in general paid with overnight interest rate. As a consequence, it is considered as a secured lending rate, i.e. a proxy of risk-free rate. It is natural to apply OIS implied rates for discounting in financial calculation. Even though Libor and Euribor are widely used as reference for swaps, OIS is gaining increasing popularity. The OIS yield curve construction is similar to that for Libor rate based instruments.
## 金融代写|金融衍生品代写Financial derivatives代考|Stock Dividend
A stock dividend is a payment (e.g. yearly or quarterly) made by a corporation to its shareholders as a distribution of profits. The dividend amount is decided by the Board of the company at each time. For a detailed discussion on the dividend policy and practice, we refer to [72].
When a dividend is declared, an ex-dividend date is specified. It is the date on which shares bought no longer come attached with the right to be paid the declared dividend. Other factors remaining equal, the share price will normally drop on the ex-dividend date by the amount equivalent to the after-tax dividend. Before exdividend date, the stock is said to trade cum dividend.
A stock dividend can be either a cash dividend in monetary form, or a stock dividend which involves the company issuing more shares to its existing shareholders. For example, a 5\% stock dividend means that the shareholders receive one new share for every twenty already owned shares. Unlike the cash dividend, the stock dividend does not change the company’s market capitalization. In modelling, stock dividends are also called proportional dividends.
Suppose that a stock pays a dividend value of $D$ with ex-dividend date $t_d$. Let $S_{t_d-}$ be the stock price just before the ex-dividend date. The quantity $d=D / S_{t_d}$ is called the dividend yield.
Obviously, $S_{t_d}$ cannot be equal to $S_{t_d}$. If it was, the strategy of buying the stock immediately before $t_d$, collecting the dividend, and selling straight away, would yield a risk-free profit. In fact, in the absence of other factors such as taxes, the asset price must fall by exactly the amount of the dividend payment. That is, for a stock paying both proportional dividend at rate $d^{\text {prop }}$ and cash dividend amount $D^{\text {cash }}$, we have
$$S_{t_d}=S_{t_{\bar{d}}}\left(1-d^{\text {prop }}\right)-D^{\text {cash }} .$$
In continuous-time modelling, the proportional divided rate is the value $d$ such that $e^{-d}=1-d^{\text {prop }}$. Hence,
$$S_{t_d}=S_{t_d^{-}} e^{-d}-D^{c a s h}$$
# 金融衍生品代考
## 金融代写|金融衍生品代写Financial derivatives代考|Overnight Indexed Swap
$$R_k=\left[\prod_{i=1}^{N_{f i z}^k}\left(1+\frac{r_i \times n_i}{360}\right)-1\right] \frac{360}{N_k},$$
$R_k$ : OIS 的速率 $k$-th期
$N_{f i x}^k$ : 隔夜利率定价的总数 $k$-th期
$r_i$ : Eonia 日定盘价 $i$
$n_i$ : 涵盖的日历天数 $r_i$
$N_k$ : 日历的总天数 $k$-th 期
OIS 利率比相应的银行同业拆借利率如 Libor 和 Euribor 意味着风险更小，因为 OIS 利率基于实际 交易，这使得它更难被操纵。
## 金融代写|金融衍生品代写Financial derivatives代考|Stock Dividend
$$S_{t_d}=S_{t_d}\left(1-d^{\text {prop }}\right)-D^{\text {cash }}$$
$$S_{t_d}=S_{t_d^{-}} e^{-d}-D^{c a s h}$$
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Math作业代写、数学代写常见问题
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http://math.stackexchange.com/questions/165663/practical-implications-of-a-vector-space-being-a-topological-vector-space | # Practical implications of a vector space being a topological vector space
I have a space $V$ and I lately discovered that it's a topological vector space. What are the practical implications of that?
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Over what field? – hardmath Jul 2 '12 at 11:54
Did you discover a vector space $V$ had a topology or did you discover a topological space $V$ was a vector space? (I'm assuming it was the former, but I'm just curious to see if my guess is right.) – rschwieb Jul 2 '12 at 12:18
You might want to add more of your thoughts to stave off downvotes. – rschwieb Jul 2 '12 at 14:19
Hi, welcome to Math.SE. Your question, as stated, falls rather borderline on this FAQ guideline. I would suggest that you follow rschwieb's advice and provide more context to focus the scope of the question. – Willie Wong Jul 3 '12 at 9:21
If $V$ is a vector space over the reals $\mathbb{R}$, then your "discovery" it has a topology is not much to write (or ask) about. The finite-dimensional real vector spaces are also known as Euclidean spaces, and these are the simplest examples of Hilbert spaces. There is some synergy between topology and vector space properties (as more generally is the case for topological groups). But you've not given us much in the way of a question to answer. -1 – hardmath Jul 5 '12 at 3:07
Another thing is that even if you only require the separation axiom $T_0$, because of the way the vector space interacts with the topology, the topology must actually even be $T_{3\frac{1}{2}}$! If it's a finite dimensional vector space, you also have that $V$ is locally compact.
Another thing is that the continuous space of linear functionals $V^\ast$ gives rise to another interesting topology on $V$. | {"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": 0.8990061283111572, "perplexity": 459.3375260212866}, "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/1422122152935.2/warc/CC-MAIN-20150124175552-00137-ip-10-180-212-252.ec2.internal.warc.gz"} |
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Page 1 of 2 | {"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": 0.8228979706764221, "perplexity": 4486.735003755085}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2013-48/segments/1387345769117/warc/CC-MAIN-20131218054929-00025-ip-10-33-133-15.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/number-of-distinct-base.260262/ | # Number of distinct base
1. Sep 29, 2008
### infinityQ
Hello, everyone.
I would like to get some concrete examples of the number of distinct bases of k-dimensional vector space W over a finite field F with q elements.
The formula for the number of distinct bases of W is ( p 412 Dummit )
(q^k - 1 )(q^k - q)(q^k - q^2)....(q^k - q ^(k-1) )
I am having a hard time finding an example of F with 2 elements and W be 2-dimensional vector space. According to the formula, 6 distinct bases of W should be acquired.
I will appreciate if anyone shows these 6 distinct bases of W.
2. Oct 1, 2008
### OfirD
take the $$Z_2$$ field and the vector space $$(Z_2)^2$$ meaning the vectors are { (0,0), (0,1), (1,0), (1,1) }
any two of the three last vectors are a base for the vector space
3. Oct 1, 2008
### infinityQ
6 distinct bases of W might be
(0,1)(1,0)
(0,1)(1,1)
(1,0)(0,1)
(1,0)(1,1)
(1,1)(0,1)
(1,1)(1,0)
But my question is second one and fifth one, for instance, does not look distinct. So it seems to me just four distinct bases exists for W.
Any suggestion?
4. Oct 1, 2008
### morphism
That formula counts ordered bases and not just any bases. So your second and fifth bases are actually different in this sense. | {"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": 0.7793141603469849, "perplexity": 934.3312810645629}, "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-2018-26/segments/1529267863939.76/warc/CC-MAIN-20180620221657-20180621001657-00063.warc.gz"} |
http://wright.tools/en/stable/api/WrightTools.data.Data/WrightTools.data.Data.level.html | # WrightTools.data.Data.level¶
Data.level(channel, axis, npts, *, verbose=True)[source]
Subtract the average value of npts at the edge of a given axis.
Parameters: channel (int or str) – Channel to level. axis (int) – Axis to level along. npts (int) – Number of points to average for each slice. Positive numbers take points at leading indicies and negative numbers take points at trailing indicies. verbose (bool (optional)) – Toggle talkback. Default is True. | {"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": 0.2400122433900833, "perplexity": 11952.60559199553}, "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-2019-04/segments/1547583660020.5/warc/CC-MAIN-20190118090507-20190118112507-00629.warc.gz"} |
http://science.sciencemag.org/content/312/5776/973 | EDITORIAL
# Science as Smoke Screen
See allHide authors and affiliations
Science 19 May 2006:
Vol. 312, Issue 5776, pp. 973
DOI: 10.1126/science.1129508
The Kauai Creeper, a sparrow-sized songbird restricted to the Hawaiian island of Kauai, would seem to fit anyone's definition of an endangered species. Fewer than 1500 individuals survive in an area of only 86 km2; its numbers are declining and it is under assault from non-native predators, pathogens, and competitors. Despite having been listed as “Critically Endangered” by the World Conservation Union, the Kauai Creeper hasn't yet earned a place on the U.S. endangered species list. In this respect, it has plenty of company. Thousands of U.S. species in grave danger of extinction have yet to be accorded protection under the Endangered Species Act of 1973 (ESA).
Fortunately, 1300 species, subspecies, and populations have been given protection under the ESA. Some, like the bald eagle, have recovered to a level that allows them to be removed from the list. Many others, although not yet out of danger, have been saved from extinction because of protection provided by the ESA. Furthermore, the U.S. Fish and Wildlife Service (FWS) has made very few errors in listing species during the 33 years it has been administering the ESA; only 10 of 1300 species (<1%) have had to be delisted because subsequent information indicated that the original decision to protect them was erroneous.
Given the enormous backlog of unprotected species in danger of extinction, one would expect Congress to expedite their protection. Instead, a bill to overhaul the ESA that passed the U.S. House of Representatives in September 2005 (H.R. 3824) would make it harder to protect endangered species, and similar “reform” legislation is now being discussed in the Senate. The pretense for the bill is to improve science, but instead H.R. 3824 would limit the use of well-tested population models for determining whether to add a species to the endangered list or for setting recovery goals. It would also add layers of time-consuming review before recovery plans could be finalized or federal agencies could act to help endangered species. Such changes will make the ESA neither scientifically sounder nor more effective.
Concerned that the scientific foundation of the ESA could be weakened by these sorts of changes, 17 scientific societies, including the Society for Conservation Biology-North America, Ecological Society of America, American Fisheries Society, Entomological Society of America, Society for Range Management, and The Wildlife Society, recently released a statement on the use (and misuse) of science in the ESA.* The statement concludes that the FWS already has effective processes in place to gather and use the best available scientific information for decision-making. However, the groups recommended the creation of an independent science advisory panel, similar to those used at the Environmental Protection Agency and elsewhere, to advise the Secretary of the Interior on issues where significant scientific uncertainty exists.
Earlier protection of rare and declining species, before they reach the brink of extinction, will greatly increase the probability that those species can be recovered. The FWS should work with the scientific community to develop clear quantitative criteria for identifying what constitutes an endangered species. Similar criteria were developed by scientists and adopted in 2001 by the World Conservation Union. The new criteria ensured consistency in determining which species should be considered imperiled.
None of this can happen unless the agencies in charge of implementing the ESA have adequate funding. The median expenditure per listed species in 2004 was only about $5500. Even this figure is somewhat deceptive because a mere 50 species (out of 1300) received 84% of all funds from the FWS and National Oceanic and Atmospheric Administration. Ultimately, too many species are dwindling for lack of attention because there isn't enough money to pursue conservation research and recovery actions in their interest. A recent study by environmentalists recommended an increase of$68 million in the annual budget (which is probably a conservative figure).
Critics of federal regulatory policies often plead for “sound science,” a cryptic rallying cry for those who really want to discourage regulation. Congress shouldn't be allowed to get away with using it as a smokescreen for eviscerating an important and successful law like the ESA. Congress did well in unanimously supporting the designation of 11 May as the first official “Endangered Species Day.” However, they'll need to do more than that to show that America's commitment to the goals of the ESA is serious. | {"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": 0.17369410395622253, "perplexity": 3677.03988393173}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376827281.64/warc/CC-MAIN-20181216051636-20181216073636-00135.warc.gz"} |
http://caspoc.com/help/referenceguide/library_advancedelectricaldrives_control_scalar_pilimtau.php | PILIMtau - Limited PI controller K,tau
Connection Diagram:
IN PI
Connections(13) Position Remark PI Right Output IN Left Input
Parameters(4) Default Remark Min -1e6 Minimum output limit Max 1e6 Maximum output limit tau 1 Integration time constant tau K 1 Proportional Gain
Function PI controller where the integration I is limited between min and max Parameters are specified as the proportional gain K and time constant tau Special The limiter is inside the integrator I and therefore has anti-windup
Status Standard Export of Embedded C Code YES | {"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": 0.8951941728591919, "perplexity": 6972.686068973833}, "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-2019-09/segments/1550247484928.52/warc/CC-MAIN-20190218094308-20190218120308-00240.warc.gz"} |
https://iwaponline.com/hr/article-abstract/44/5/917/1154/A-validation-of-river-routing-networks-for | Underpinning all hydrological simulations is an estimate of the catchment area upstream of a point of interest. Locally, the delineation of a catchment and estimation of its area is usually done using fine scale maps and local knowledge, but for large-scale hydrological modelling, particularly continental and global scale modelling, this level of detailed data analysis is not practical. For large-scale hydrological modelling, remotely sensed and hydrologically conditioned river routing networks, such as HYDRO1k and HydroSHEDS, are often used. This study evaluates the accuracy of the accumulated upstream area in each gridpoint given by the networks. This is useful for evaluating the ability of these data sets to delineate catchments of varying scale for use in hydrological models. It is shown that the higher resolution HydroSHEDS data set gives better results than the HYDRO1k data set and that accuracy decreases with decreasing basin scale. In ungauged basins, or where other local catchment area data are not available, the validation made in this study can be used to indicate the likelihood of correctly delineating catchments of different scales using these river routing networks.
This content is only available as a PDF. | {"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": 0.8256881237030029, "perplexity": 1760.0221623897492}, "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-2019-18/segments/1555578529606.64/warc/CC-MAIN-20190420100901-20190420122901-00331.warc.gz"} |
https://blender.stackexchange.com/questions/4862/un-hiding-faces-and-double-sided-textures | Un-hiding faces and double sided textures
Typically if you look at the back of a textured face you don't see anything but a transparent square.
Is there any way you could make the front and back of the face textured without flipping the direction of the face?
Also, how can you unhide the faces that you previously hidden with H?
• Please try to avoid asking more than one question in a single post. (It's Alt+H, but for future reference that should be a separate question in a separate post) – gandalf3 Nov 14 '13 at 1:44
In BI both sides of a face should be textured by default in the render.
If you mean in the viewport, you can switch the viewport shading to Textured in 3D view > Header and set the shading to GLSL in 3D view > Properties region (N) > Shading. Also make sure that Backface Culling is disabled in the same panel.
Note that you will need to add lamps to the scene, or enable temporarily Shadeless in Properties > Material > Shading.
Shadeless is good for editing purposes where you want to see the texture everywhere (no shadows or shading). Note that this will affect the final render, so remember to disable it when you are done.
For unhiding faces, press AltH, or 3D view > Header > Mesh > Show/Hide > Show hidden in edit mode.
• Well I am a bit confused now. LOL. Sorry for asking 2 questions in one. I changed all my settings to what you have but now my character is black. Also I don't know what I am doing wrong but I go into edit mode click H on a selected face then click Alt+H and the face is still missing. – Pixels_ Nov 14 '13 at 1:54
• @GarrettLozano Strange. It works for me.. Try it from the Mesh menu. Is it possible you could upload your .blend? – gandalf3 Nov 14 '13 at 1:59
• Here is the link for the file upload: pasteall.org/blend/25235. I have all these simple questions because I am still in high school and have worked with blender for 2 weeks. – Pixels_ Nov 14 '13 at 2:06
• Thanks. There's nothing wrong with that, (everyone's new at some point) but just try to put one question per post. (this site is a bit different from a forum, in that there is supposed to be one question and several answers which get voted to the top) – gandalf3 Nov 14 '13 at 2:10
• It seems the reason your model appears black is there are no lamps in the scene. – gandalf3 Nov 14 '13 at 2:30 | {"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": 0.16856738924980164, "perplexity": 1103.620135593806}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-05/segments/1579250593937.27/warc/CC-MAIN-20200118193018-20200118221018-00273.warc.gz"} |
https://codereview.stackexchange.com/questions/213867/python-code-to-get-all-lines-between-two-keyword-lines-in-a-file-with-exception | # Python code to get all lines between two keyword lines in a file (with exceptions)
I have coded multiple variations on this and would like to make it generic, to avoid coding any more variations.
I often want to parse a text file and split it into chunks, generally those lines between two lines containing known keywords.
E.g.
• zero or more lines of text
• A start
• zero or more lines of text -A end
• zero or more lines of text
• B start
• zero or more lines of text
• B end
• zero or more lines of text
• B start
• zero or more lines of text
• C end
• zero or more lines of text
Note that “zero or more”.
Also, note that some sections are optional. For instance, knowing that there are no lines between sections, to get the A related text, I can specify a start as any line containing “A start” and an end as any line containing “A end”. BUT, since B and C are optional, my end for A is any one of “A end”, “B end” or “C end”.
And sometimes I know that I am on the start line (it may not even contain a keyword).
# +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
# Given the lines and current line number, this function reads
# from the current line (or the first following line containing the start string,
# returning empty string if not found) and returns all lines between
# the line after that and the first line containing any of the end strings
# (or end of lines) - not including the line with the terminating string.
#
# @param [in] lines - list of strings
#
# @param [in] lineNumber - current index to lines parameter
#
# @param [in] searcrhForStartString - Bool; set to False if currently positioned
# at the start line, and there is no start
# string to search for
#
# @param [in] startStrings - list of strings (even if there is only one)
# If param searcrhForStartString == True
# then search param lines until one contains
# one of these lines. Returned lines will start
# at the next line, skipping the keyword
# (start at current line if param
# searcrhForStartString is False).
#
# Will return an empty list if no match is found
# @param [in] endStrings - a list (even if there is only one) of strings.
# Search until a line containing one of these is found
# (or end of lines) and return all lines
# from the first until the line prior to this
# (do not include keyword line)
#
# @param [in] errorOnEndOfLines - if True, will return an empty list
# if no end string is found
# before the end of param lines
# @return - list of strings
#
# ToDo: consider (a) parameter(s) to indicate that lines must start with,
# or be equal to, a search string, rather than just containing?
# That would make this even more generic, but would require (an) extra parameter(s)
#
def GetLinesBetween(lines,lineNumber, searcrhForStartString, startStrings, endStrings, errorOnEndOfLines):
try:
result = [] # emmpty list
line = lines[lineNumber]
if searcrhForStartString:
while not any(keyword in line for keyword in startStrings):
lineNumber += 1
if lineNumber == len(lines):
if errorOnEndOfLines:
result.clear()
return result
line = lines[lineNumber]
#serach string matched, if requested, so advance one line to skip it
lineNumber += 1
line = lines[lineNumber]
# Line number now indexes the first line of what we want to return
while lineNumber < len(lines):
if any(keyword in line for keyword in endStrings):
return result
result.append(line)
lineNumber += 1
if not lineNumber == len(lines):
line = lines[lineNumber]
if lineNumber == len(lines):
if errorOnEndOfLines:
result.clear()
return result
#-----------------------
except Exception as err:
print('Exception:')
exc_type, exc_value, exc_tb = sys.exc_info()
traceback.print_exception(exc_type, exc_value, exc_tb)
sys.exit(0)
• The function specification itself is rather complicated, and could probably be improved, if you included the code that calls this function. Including some sample inputs and outputs would help clarify the expected behavior as well. – 200_success Feb 20 '19 at 10:29
This is some interesting code, thanks for posting it here. Good work Mawg.
Nitpicking
# +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
# Given the lines and current line number, this function reads
# from the current line (or the first following line containing the start string,
Please get rid of banners like this. If you are using an IDE such as PyCharm it can generate documentation comments for you. Current python industry standard regarding documentation is PEP-287.
lines,lineNumber,
Use consistent spacing. I personally like to use black to format my code. But you can use anything that formats to PEP8.
GetLinesBetween, lineNumber, ...
Please use correct PEP8 style such as get_lines_between and line_number?
#-----------------------
except Exception as err:
print('Exception:')
exc_type, exc_value, exc_tb = sys.exc_info()
This is sloppy exception handling.
• If you must use a catch-all: Maybe use a higher level method that captures exceptions and change this to try_get_lines_between or _get_lines_between as a more readable alternative. Why: separation of error handling and application logic - It is up to you to decide if this is best course of action.
• You can also create your own exceptions if that is more suitable to you. You can for example raise them instead of returning empty list if it is more suitable.
• Use a logger instead of print to log exceptions. logger.exception is more suitable for this.
• Instead of sys.exit(0) - maybe exit with non zero value so you know that there was an error.
emmpty, serach
# ToDo: consider (a) parameter(s) to indicate that lines must start with,
# or be equal to, a search string, rather than just containing?
# That would make this even more generic, but would require (an) extra parameter(s)
#
People sometimes forget to do to-dos. Use a software like JIRA, Github Projects to track your tasks and remove them from code. It's OK to create tasks for yourself.
How would I design this better?
• Use generators instead of creating lists, so you can create pipeline of functions and can even read multiple files, and also save some memory.
• Maybe use Aho-Corasick algorithm (Trie based) to match against multiple strings.
• Sensible defaults - there are lot of parameters for this function. If you add default values then API would be easier to use.
• Thanks very much for the feedback. 1) "generate documentation comments for you" - wilco 2) "Use consistent spacing" - I thought that I did, but will check 3) "use correct PEP8 style" for variable/function names - alas, several decades of embedded C programming have ingrained this, so I am unlikely to change :-( 4) "This is sloppy exception handling ... •Use a higher level methods that captures exceptions and a try_get_lines_between method" - I don't see what that would buy me, just shoving it upwards into a wrapper; what am I missing? ---> – Mawg says reinstate Monica Feb 20 '19 at 14:46
• ---> 5) "Use a logger instead of print to log exceptions" - sounds good. Thanks for all of your feedback. Btw, 6) what do you think of the ToDo? and 7) the function does not have to return lines as it never changes it (I just did my own review :-) – Mawg says reinstate Monica Feb 20 '19 at 14:47
• @Mawg there are various ways to do your todo. You can for example pass lambda functions as arguments (default to in), pass lambda line, keyword: line.startswith(keyword) when you want to handle starts with. Flag functions however become more complex overtime so be warned. – bhathiya-perera Feb 20 '19 at 16:11
• I've added more points to answer as well. – bhathiya-perera Feb 20 '19 at 16:15 | {"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": 0.2556896209716797, "perplexity": 3784.6793240173192}, "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/1620243989012.26/warc/CC-MAIN-20210509183309-20210509213309-00051.warc.gz"} |
https://brilliant.org/problems/inspired-by-lakshya-sinha-2/ | # Inspired by Lakshya Sinha
Algebra Level 4
Find the minimum value $$m$$ and the maximum value $$M$$ of $f(x,y,z)=x^3+\frac{y^3}{4}+\frac{z^3}{9}$ when $$x+y+z=12$$, where $$x,y$$ and $$z$$ are non-negative real numbers. Enter $$m+M$$.
× | {"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": 0.45470914244651794, "perplexity": 498.57296954200996}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-17/segments/1524125945942.19/warc/CC-MAIN-20180423110009-20180423130009-00527.warc.gz"} |
https://www.physicsforums.com/threads/one-question.15200/ | # One question
1. Feb 26, 2004
### lovelylm1980
I have been driving myself crazy trying to figure out this problem, for a while now. I just can't get the right answer. should the number of turns be multiplied or divided by the radius? Please help me out.
Two circular coils, concentric and lying in the same plane, produce magnetic fields such that the net magnetic field is zero at the center. The number of turns and radius are 5 and 10.00 cm for the inner coil, and 3 and 13.8 cm for the outer coil. What is the magnitude and direction (positive for counterclockwise, negative for clockwise) of the outer current if the inner current is 2.00 A and counterclockwise ?
2. Feb 26, 2004
### turin
Why would you think that you needed to do either one? | {"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": 0.9179962873458862, "perplexity": 523.7968858629893}, "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/1539583509336.11/warc/CC-MAIN-20181015163653-20181015185153-00130.warc.gz"} |
https://datascience.stackexchange.com/questions/21877/how-to-use-the-output-of-gridsearch | # How to use the output of GridSearch?
I'm currently working with Python and Scikit learn for classification purposes, and doing some reading around GridSearch I thought this was a great way for optimising my estimator parameters to get the best results.
My methodology is this:
1. Split my data into training/test.
2. Use GridSearch with 5Fold Cross validation to train and test my estimators(Random Forest, Gradient Boost, SVC amongst others) to get the best estimators with the optimal combination of hyper parameters.
3. I then calculate metrics on each of my estimators such as Precision, Recall, FMeasure and Matthews Correlation Coefficient, using my test set to predict the classifications and compare them to actual class labels.
It is at this stage that I see strange behaviour and I'm unsure how to proceed. Do I take the .best_estimator_ from the GridSearch and use this as the 'optimal' output from the grid search, and perform prediction using this estimator? If I do this I find that the stage 3 metrics are usually much lower than if I simply train on all training data and test on the test set. Or, do I simply take the output GridSearchCV object as the new estimator? If I do this I get better scores for my stage 3 metrics, but it seems odd using a GridSearchCV object instead of the intended classifier (E.g. a random Forest) ...
EDIT: So my question is what is the difference between the returned GridSearchCV object and the .best_estimator_ attribute? Which one of these should I use for calculating further metrics? Can I use this output like a regular classifier (e.g. using predict), or else how should I use it?
Decided to go away and find the answers that would satisfy my question, and write them up here for anyone else wondering.
The .best_estimator_ attribute is an instance of the specified model type, which has the 'best' combination of given parameters from the param_grid. Whether or not this instance is useful depends on whether the refit parameter is set to True (it is by default). For example:
clf = GridSearchCV(estimator=RandomForestClassifier(),
param_grid=parameter_candidates,
cv=5,
refit=True,
error_score=0,
n_jobs=-1)
clf.fit(training_set, training_classifications)
optimised_random_forest = clf.best_estimator_
return optimised_random_forest
Will return a RandomForestClassifier. This is all pretty clear from the [documentation][1]. What isn't clear from the documentation is why most examples don't specifically use the .best_estimator_ and instead do this:
clf = GridSearchCV(estimator=RandomForestClassifier(),
param_grid=parameter_candidates,
cv=5,
refit=True,
error_score=0,
n_jobs=-1)
clf.fit(training_set, training_classifications)
return clf
This second approach returns a GridSearchCV instance, with all the bells and whistles of the GridSearchCV such as .best_estimator_, .best_params, etc, which itself can be used like a trained classifier because:
Optimised Random Forest Accuracy: 0.916970802919708
[[139 47]
[ 44 866]]
GridSearchCV Accuracy: 0.916970802919708
[[139 47]
[ 44 866]]
It just uses the same best estimator instance when making predictions. So in practise there's no difference between these two unless you specifically only want the estimator instance itself. As a side note, my differences in metrics were unrelated and down to a buggy class weighting function. [1]: http://scikit-learn.org/stable/modules/generated/sklearn.model_selection.GridSearchCV.html#sklearn.model_selection.GridSearchCV.fit
• Thanks for your post @Dan, it is very helpful. I wanted to ask you for one clarification. At the latter case, if I have refit=False then clf.fit won't be done with the best classifier? Sep 28, 2018 at 9:42
• @PoeteMaudit The refit parameter tells the GridSearchCV function to take the best parameters found, and retrain the model using those parameters on the whole dataset. If refit=False, then best_estimator is not available, according to the documentation: scikit-learn.org/stable/modules/generated/… Mar 13, 2019 at 9:51
• Thank you for the post @DanCarter. I was breaking my head over this. The devil is the detail as the proverb goes. Apr 26, 2020 at 11:31
GridSearchCV lets you combine an estimator with a grid search preamble to tune hyper-parameters. The method picks the optimal parameter from the grid search and uses it with the estimator selected by the user. GridSearchCV inherits the methods from the classifier, so yes, you can use the .score, .predict, etc.. methods directly through the GridSearchCV interface. If you wish to extract the best hyper-parameters identified by the grid search you can use .best_params_ and this will return the best hyper-parameter. You can then pass this hyper-parameter to your estimator separately.
Using .predict directly will yield the same results as getting the best hyper-parameter through .best_param_ and then using it in your model. By understanding the underlining workings of grid search we can see why this is the case.
## Grid Search
This technique is used to find the optimal parameters to use with an algorithm. This is NOT the weights or the model, those are learned using the data. This is obviously quite confusing so I will distinguish between these parameters, by calling one hyper-parameters.
Hyper-parameters are like the k in k-Nearest Neighbors (k-NN). k-NN requires the user to select which neighbor to consider when calculating the distance. The algorithm then tunes a parameter, a threshold, to see if a novel example falls within the learned distribution, this is done with the data.
How do we choose k?
Some people simply go with recommendations based on past studies of the data type. Others use grid search. This method will be able to best determine which k is the optimal to use for your data.
How does it work?
First you need to build a grid. This is essentially a set of possible values your hyper-parameter can take. For our case we can use $[1, 2, 3, ..., 10]$. Then you will train your k-NN model for each value in the grid. First you would do 1-NN, then 2-NN, and so on. For each iteration you will get a performance score which will tell you how well your algorithm performed using that value for the hyper-parameter. After you have gone through the entire grid you will select the value that gave the best performance.
This goes against the principles of not using test data!!
You would be absolutely right. That is the reason grid search is often mixed with cross-validation. So that we keep the test data completely separate until we are truly satisfied with our results and are ready to test. $n$-fold cross-validation takes a training set and separates it into $n$ parts. It then trains on $n-1$ folds and tests on the fold which was left out. For each value in the grid, the algorithm will be retrained $n$ times, for each fold being left out. Then the performance across each fold is averaged and that is the achieved performance for that hyper-parameter value.
The selected hyper-parameter value is the one which achieves the highest average performance across the n-folds. Once you are satisfied with your algorithm, then you can test it on the testing set. If you go straight to the testing set then you are risking overfitting.
• Hi Jah, this is a good answer but I'm still none the wiser as to the answer of my question. I've updated the question title and the question itself to try and make things more clear. Aug 1, 2017 at 13:59
• Write your own grid search. It's literally make an array, then add a for loop around your model. Then at the end of your for loop record the resulting performance into an array. After you have gone through all the possible values in your grid, look at the arrays of performances, and pick out the best one. That is the optimal value for your hyper-parameter. Relying on built-in functions for the basics is highly not recommended for data science. Data varies so wildly and its best for you to have control! Aug 1, 2017 at 14:03
• GridSearchCV lets you combine an estimator with GridSearchCV setting. So it does exactly what we just discussed. It then picks the optimal parameter and uses it with the estimator you selected. GridSearchCV inherits the methods from the classifier, so yes, you can use the .score, .predict, etc.. methods directly through the GridSearchCV interface. I do not recommend doing this however, easier tools means less control. For something so simple as a grid search just code it yourself. Aug 1, 2017 at 14:09
• @DanCarter, 4/5 hyper-parameters is nothing in this field. Wait till you get to models where you will need to control for false-positive rates using Neyman-Pearson Lemma which immediately adds 4 hyper-parameters per equation. Regardless, this is not reinventing the wheel. It's 5 lines of code. You should really write your own routines to understand what is happening behind the scenes of these packages and to give you more control. But, especially for functions SO simple as a grid search. Aug 1, 2017 at 14:15
• This answer does not address the question, which is regarding GridSearchCV usage. Aug 1, 2017 at 17:38 | {"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": 0.296062707901001, "perplexity": 851.442263493839}, "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/1656103034930.3/warc/CC-MAIN-20220625095705-20220625125705-00002.warc.gz"} |
http://math.stackexchange.com/questions/23242/what-is-the-math-equation-that-satisfies-conditions-given-below | What is the math equation that satisfies conditions given below?
Variable $z$ varies from $-50.0$ to $18.0$. Find the equation that gives $d$ such that when $z=-50$, $d = 0.1$; and when $z = 18.0$, $d = 1.0$. The values of $d$ vary from 0.1 to 1 uniformly depending on the value of $z$ with the boundary conditions given above.
-
Let $d = az + b$. Solve two equations in two variables. – Yuval Filmus Feb 22 '11 at 17:28
Is this homework? Try finding the slope of the line going through the two points $(-50,0.1)$ and $(18,1)$, and then working out what the $y$-intercept has to be. – Zev Chonoles Feb 22 '11 at 17:33
No this is not homework. Just writing some program. So how do I find constants and a and b if the equation looks like d = az+b ? Is there mathematical way to find these constants? – user7378 Feb 22 '11 at 17:54
As $d$ changes from $0.1$ to $1$ (a change of $1-0.1=0.9$), $z$ changes from $-50$ to $18$ (a change of $18--50=68$), so for every change of $1$ in $z$, $d$ changes by $\frac{0.9}{68}$. When $z=-50$, $d=0.1$. So, an equation relating $z$ and $d$ is $$d-0.1=\frac{0.9}{68}(z+50).$$ | {"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": 0.9790932536125183, "perplexity": 165.0298707069373}, "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-2015-48/segments/1448398468396.75/warc/CC-MAIN-20151124205428-00325-ip-10-71-132-137.ec2.internal.warc.gz"} |
https://www2.math.binghamton.edu/p/seminars/comb/abstract.201502izm | ### Sidebar
seminars:comb:abstract.201502izm
# Variational Properties of the Discrete Hilbert-Einstein Functional
## Abstract for the Geometry/Topology Seminar 2015 February 5
The discrete Hilbert-Einstein functional (also known as Regge action) for a 3-manifold glued from euclidean simplices is the sum of edge lengths multiplied with angular defects at the edges. There is an analog for hyperbolic cone-manifolds; a discrete total mean curvature term appears if the manifold has a non-empty boundary. Variational properties of this functional are similar to those of its smooth counterpart. In particular, critical points correspond to vanishing angular defects, i.e. to metrics of constant curvature. I survey isometric embeddings and rigidity results that can be obtained by studying the second derivative of the discrete Hilbert-Einstein and speak about possible future developments. | {"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": 0.8133406639099121, "perplexity": 740.0285139057473}, "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/1593655912255.54/warc/CC-MAIN-20200710210528-20200711000528-00297.warc.gz"} |
https://lingtran.net/PT9Vid---Drafting | # Stage 1: Drafting
## Vidéo 1.1 How to View Tasks Assigned to you
• Open Assignments and progress by clicking on the blue button
The Assignments and Progress window opens, showing My Tasks in the Current Priority or the last view.
• Prev priority- previous book with tasks
• Next priority - next book with tasks
• Where it says Current Priority, click to view the menu.
• Click Current Book.
This is the default filter if your administrator has not set up Priorities.
• View tasks in another book by clicking Next book or Previous book.
• Hover the mouse over the information icon to find out what is blocking it.
## Video 1.2.1 Understanding USFMs - Introduction
In this video you learn all about how Paratext uses special tags called USFMs. The tags
• provide the structure of the document by identifying the start of each book, as well as the sections within them.
• facilitate the appropriate formatting of the translation by the typesetter according to what each bit of text really is, such as a heading, chapter number, or something special in the Bible text itself such as poetry or a quotation.
USFM stands for Unified Standard Format Marker.
USFMs always start with a backslash, then a code, then a space. (e.g. \ft )
With the exception of a closing marker which ends with an asterisk and doesn't need a space.
• The most common USFMs are:
\p (paragraph) \c (chapter) \v (verse)
• The latest USFM standard is online - paratext.org/about/usfm, then click on documentation.
## Adding markers in different views
### Video 1.2.2a Adding Markers in Standard View
This video looked at how to insert Unified Standard Format markers or USFMs in standard view.
• Standard view shows the USFM markers, but they are small and grey. This view is recommended for ordinary work when drafting and editing a translation.
• In this view there are some helps for entering the right marker.
• Press ENTER to add a new paragraph
Paratext automatically opens a menu showing us the possible markers for starting a paragraph, the most frequent are at the top.
• Either use the mouse or type the appropriate letter
• E.g. type P and press ENTER
• Select the words you wish to mark
• Press \
• Select the marker from the list
### Video 1.2.2b How to work with USFMs in Formatted View
In this video we changed to Formatted view and learnt about adding and removing USFM styles here.
The view options are available on the menu for the project.
• Expand the menu if necessary .
The option with the checkmark or tick is the currently selected view.
• Click Formatted.
The view changes and the USFM tags are hidden.
Entering character markers
• Press \ backslash
The character marker menu just as in Standard view.
Entering paragraph breaks
• Press ENTER
A new normal paragraph is inserted.
Using style chooser on the toolbar
In both Standard and Formatted views the marker which applies to the text is shown in the Style chooser on the toolbar.
• Select the text
• Click the style chooser.
The most commonly occurring markers are shown at the top.
• Select a marker
• If we select a paragraph style, it will be applied to the entire paragraph.
• If we select a character style will be applied to the selected text.
Removing an unwanted character style.
• Select the text
• On the Style chooser select Clear formatting.
The text goes back to normal and behind the scenes the USFM tags have been removed.
### Video 1.2.2c How to use Basic View
In this video we learnt how to work in Basic view. Basic view shows the USFM markers, but you cannot change the markers or add markers in this view. You can only type and have the cursor in the white areas. To use this view, someone needs to have set up all the markers needed in your translation for you beforehand.
To switch to Basic view,
• Open the menu for the project .
• Expand the menu if needed.
• Under view, click Basic.
To move to the next place to type
• Use the arrow key to move to the next place to type.
• Or click on the text box to move the cursor there.
### Video 1.2.2d What is Unformatted View for?
In this video we look at Unformatted View.
To switch to Unformatted view,
• Open the project menu .
• Expand the menu if needed.
• Under view, click Unformatted.
Unformatted view shows the entire document as plain text.
Note:
• In unformatted view the USFM tags and the Bible text are not visually distinguished by any kind of formatting.
• There are no tools to help you apply or enter USFM tags, but you can edit them directly by simply typing.
• This view facilitates manual editing of the tags if needed.
• This view is not recommended for drafting the translation.
### Video 1.2.2e What is Preview?
In this video we learn about the view called Preview.
To switch to Preview
• Open the project menu .
• Expand the menu if needed.
• Under View, click Preview.
This view looks very like Formatted view, with USFM tags hidden, and only their effect on the style of the text shown.
Preview goes even further to make the text look like it will be seen by eventual readers of the translation.
Note:
• There is no grey highlighting of the verse numbers.
• A figure is sized more appropriately.
• In Preview, you cannot edit at all.
• You cannot edit the text in any way.
• Clicking the figure does not bring up the Figure Properties dialog box.
• You can still click a footnote or cross reference caller to open and view the footnote pane.
Preview view looks similar to Formatted view but does not allow any editing of the text or styles at all.
It is useful for viewing the text without any risk of editing.
### Summary: Adding Markers in Different Views
There are five views in Paratext:
Standard view has visible but distinguished markers,formatted text, and is fully editable. Formatted view is the same, except the markers are hidden. Unformatted view has visible markers, no formatting of text or markers, and is fully editable. Basic view is the same as 'Standard view', except that only the text is editable, not the markers. Preview is the same as 'Formatted view', except that it is not editable at all.
## Video 1.2.3 Backslash Key
In this video you will learn that F5 is an alternative way to type backslash. Backslash is an important key in Paratext because it starts every USFM tag, and opens the menu of markers in Standard view and Formatted view.
Since it is not available on all language keyboards, Paratext provides alternatives.
To insert a backslash character
• Press F5 to insert \
OR
• Open the project menu .
• Expand the menu if needed.
• Under Insert, hover over Backslash (\)
A reminder of the keyboard shortcut is displayed in the lower left corner
In standard and formatted view, it brings up the menu of markers
In unformatted view, it simply enters a \
## Video 1.2.4 The Best Way to Add Verse Numbers
In this video we will learn the best way to insert verse numbers.
Many Paratext users type their translation into a book outline, that includes all the chapter and verse numbers they need up front. However, there are still times when you might need to insert a verse number.
• Place the cursor where you want the verse number to be inserted.
• Open the project menu .
• Under Insert, choose verse number.
The verse marker is inserted along with the appropriate verse number.
To use the keyboard shortcut
• Place the cursor where you want the verse number to be inserted.
• Press Ctrl+K.
The verse marker is inserted along with the appropriate verse number.
If we try to add a verse number between two consecutive verses nothing happens. If we try to add another verse number at the end of the chapter nothing happens. This feature does not allow you to add more verse numbers than there should be in the given chapter.
## Video 1.2.5 How to Mark non-Biblical Text
In this video, we will learn about how to mark non-Biblical text. Translators often include extra text in their Bible translations to introduce a book, indicate the start of a different topic in an epistle, indicate the start of a different topic in an epistle, or a different event in narrative, etc.
\s1, \s2, \s3 \s4
• Place the cursor where you want to add a section heading here.
• Press ENTER
• Type s
The section header markers are now listed.
• Type the number to match the heading above, e.g 1 and then press ENTER to confirm.
The marker is displayed in the middle of the window ready for me to enter the heading.
Book introductions
The ordinary paragraph marker should not be used in the introduction to a book.
• Place the cursor where you want to add the introduction.
• Press ENTER
• Type i
The introduction markers are now listed.
• Choose the appropriate marker.
## Typing and Editing Text
### Video 1.3a How to scroll between chapters in a window
In this video we will learn how to view more than one chapter at a time in a Paratext window. When we open a project or resource in Paratext, by default it only shows us the current chapter.
• Click the project menu .
• Click the expand arrow to view full menus.
• Under View, click Show all chapters.
Paratext loads the entire book into the Window.
• (checked = by chapter, unchecked = by book)
We recommend that you leave 'View By Chapter' checked most of the time as it can slow Paratext down when it updates the book.
### Video 1.3b How to Change the Size of the Text in a Window
In this video we will learn how to change the size of text in a Paratext window panel.
• Click the project menu .
Under View, there is a command Zoom with the current zoom level displayed and - and + either side.
• To make the text look bigger, click +.
• To make the text look smaller click -.
• Click in the window to close the menu.
• Open the menu for the project.
• In the zoom control, select the zoom level number
• Type 100.
• Press ENTER.
• Click on the window to close the menu.
Keyboard shortcut
• Ctrl + increase Ctrl - decreases it.
Zoom level is remembered when you reopen that project.
Only affects your computer, not other members.
This video was created in Paratext 8 but applies equally to Paratext 9. In this video we learn there are a few places where you must insert a paragraph marker.
You should insert a paragraph marker before verse 1 in every chapter to avoid the markers check reporting an error.
In 'standard view',
• Click where you want to put the paragraph,
• press ENTER, and then select the paragraph marker from the list.
• Click where you want to put the paragraph,
• press 'ENTER',
\s1, \s2, \s3 \s4
Remember,
• you always need a paragraph marker before verse 1 of any chapter.
• you always need a paragraph after any 'section head' or 'parallel passage heading'.
Other common markers
• \p standard paragraph
• \m for a paragraph with no first line indent,
• \nb paragraph with no break with the previous paragraph
• \pi where all the paragraph is indented,
• \q1 or \q2 for indented quotes or poetry.
## Video 1.4.1 How to use Checking Tools (Basic Checks: Chapter/Verse)
Paratext has several tools for checking the consistency and accuracy of a translation. These are called Checks. Some checks require setup. It is important to correct any problems with chapter and verse markers, because, with these errors present, it can be hard for Paratext to show us exactly where things are found (e.g. Wordlist). We recommend you start looking at these issues early, even before you finish a book.
Using the project plan
If checks have been assigned to you, they are listed in the My Tasks view in the Assignments and Progress window.
To view issues found by a check,
• Click the issue count
Paratext lists the items in a window panel.
There will be a Verses Missing issue shown for a span of text that hasn’t been drafted yet. That’s OK. Focus on the issues found in chapters you have drafted.
• Correct errors in the list as needed
• Double click the issue
Paratext moves the project to that reference.
• Verse missing - check \v and space before the number
• Duplicated verse - often space between digits
• Unknown marker - check name of marker or space before verse number
• Verse number in heading insert a paragraph marker
Run checks manually
You can also run the checks manually
• Click project ≡ menu, under Tools menu, > Run Basic Checks.
• Choose the desired checks e.g. chapter/verse numbers and markers.
• Click OK
• Correct errors in the list as needed as above.
• Rerun check to be sure error is corrected
## Video 1.5 How to Mark Texts as Complete
As you work on the tasks assigned to you in Paratext, you need to record what you have finished.This allows the team to see your progress, andmost importantlyallows other team members, who are waiting for your task to be finished, to get started on their tasks.
Open Assignments and progress
• Click on the blue button .
• Mark project task or book task as complete: click the check box
• Mark chapter task as complete: click blue +, or unmark click blue -
• For more control click none (or chapter numbers), click the chapter numbers
• Click OK
Prev (Book or Priority), Next (Book or Priority), All tasks
Remember to Send/Receive so that other team members receive the progress status information.
## Video 1.6 What is a Conflict
A conflict occurs when two or more people edit the text at the same time. Paratext gets confused and does not know which one to keep. It chooses one and adds a conflict note.
It is best to have only one translator edit a text at time. Other team members should add notes of their suggestions (see later videos on notes).
## Video 1.6.1 Paratext Conflict Notes: What they look like and how to deal with them
In this video we will see what conflict notes look like and how to deal with them. This is the same in Paratext 8 and 9.
• Click link Open unresolved conflict notes list window.
Open note and resolve conflict
• Open note
• If the note is assigned to you, or you are an administrator, there will be a dropdown list
• Click the Dropdown the list at the top
• Choose an option as appropriate
• Accept the changes Paratext accepted (leave it as is)
• Accept the changes Paratext rejected (and reject the other change)
• Merge all changes (accept both changes)
• Click OK
Special warning flag for conflict notes are either at the very beginning of the book or at the verse number.
• Resolve the note to make the flag go away. | {"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": 0.29104018211364746, "perplexity": 4432.482186116934}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046150134.86/warc/CC-MAIN-20210724063259-20210724093259-00675.warc.gz"} |
http://aas.org/archives/BAAS/v36n5/aas205/863.htm | AAS 205th Meeting, 9-13 January 2005
Session 102 Neutron Stars
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall
## [102.07] Orbital evolution of SAX J2103.4545
C. M. Heffner, M. J. Stark (Lafayette College), A. Baykal (Middle East Technical University), J. H. Swank (NASA/Goddard Space Flight Center)
We have had a program of continuous observation of SAX~J2103.5+4545 with the {\em Rossi X-Ray Timing Explorer\/} for more than two years. We have been able to unambiguously count the revolutions of the pulsar over this entire period. We have been able to construct an orbital model for the binary motion of this system which is consistent with our earlier published orbit, but which now includes an orbital period derivative for the system of -5.8\times10-5. We will present detailed results of our orbital analysis, including the results of our search for precession of the orbit. As we refine our orbital model, we hope to observe a dependence of the pulsar accretion torque on the phase of the highly eccentric orbit. This work is supported in part by a grant from NASA. | {"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": 0.814437210559845, "perplexity": 1866.3507040293816}, "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-2015-11/segments/1424936535306.37/warc/CC-MAIN-20150226074215-00101-ip-10-28-5-156.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/units-of-angular-momentum.727488/ | # Units of Angular Momentum?
1. Dec 9, 2013
### KiNGGeexD
If the units of angular velocity, ω, is expressed in rad/a what then is the units of angular momentum?
L=Iω
From this I can gather that the units are
Is this a suitable way to express angular momentum?
2. Dec 9, 2013
### rock.freak667
Yes you can express it as such. You can similarly express it N*m*s. You can sort of leave out the radian unit if you wish as that is basically a ratio of arc length to radius.
3. Dec 9, 2013
### KiNGGeexD
So if from that I calculated Kinetic energy using
E=1/2 I*ω^2
Where I=1/2MR^2
4. Dec 9, 2013
Yes.
5. Dec 9, 2013
### KiNGGeexD
:) ok thanks
Draft saved Draft deleted
Similar Discussions: Units of Angular Momentum? | {"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": 0.9886525273323059, "perplexity": 4580.481015073998}, "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/1518891815843.84/warc/CC-MAIN-20180224152306-20180224172306-00468.warc.gz"} |
http://manishearth.github.io/blog/2017/01/15/breaking-our-latin-1-assumptions/ | # Breaking Our Latin-1 Assumptions
So in my previous post I explored a specific (wrong) assumption that programmers tend to make about the nature of code points and text.
I was asked multiple times about other assumptions we tend to make. There are a lot. Most Latin-based scripts are simple, but most programmers spend their time dealing with Latin text so these complexities never come up.
I thought it would be useful to share my personal list of scripts that break our Latin-1 assumptions. This is a list I mentally check against whenever I am attempting to reason about text. I check if I’m making any assumptions that break in these scripts. Most of these concepts are independent of Unicode; so any program would have to deal with this regardless of encoding.
I again recommend going through eevee’s post, since it covers many related issues. Awesome-Unicode also has a lot of random tidbits about Unicode.
Anyway, here’s the list. Note that a lot of the concepts here exist in scripts other than the ones listed, these are just the scripts I use for comparing.
## Arabic / Hebrew
Both Arabic and Hebrew are RTL scripts; they read right-to-left. This may even affect how a page is laid out, see the Hebrew Wikipedia.
They both have a concept of letters changing how they look depending on where they are in the word. Hebrew has the “sofit” letters, which use separate code points. For example, Kaf (כ) should be typed as ך at the end of a word. Greek has something similar with the sigma.
In Arabic, the letters can have up to four different forms, depending on whether they start a word, end a word, are inside a word, or are used by themselves. These forms can look very different. They don’t use separate code points for this; however. You can see a list of these forms here
As I mentioned in the last post, U+FDFD (﷽), a ligature representing the Basamala, is also a character that breaks a lot of assumptions.
## Indic scripts
Indic scripts are abugidas, where you have consonants with vowel modifiers. For example, क is “kə”, where the upside down “e” is a schwa, something like an “uh” vowel sound. You can change the vowel by adding a diacritic (e.g ा); getting things like का (“kaa”) को (“koh”) कू (“koo”).
You can also mash together consonants to create consonant clusters. The “virama” is a vowel-killer symbol that removes the inherent schwa vowel. So, क + ् becomes क्. This sound itself is unpronounceable since क is a stop consonant (vowel-killed consonants can be pronounced for nasal and some other consonants though), but you can combine it with another consonant, as क् + र (“rə”), to get क्र (“krə”). Consonants can be strung up infinitely, and you can stick one or more vowel diacritics after that. Usually, you won’t see more than two consonants in a cluster, but larger ones are not uncommon in Sanskrit (or when writing down some onomatopoeia). They may not get rendered as single glyphs, depending on the font.
One thing that crops up is that there’s no unambiguous concept of a letter here. There is a concept of an “akshara”, which basically includes the vowel diacritics, and depending on who you talk to may also include consonant clusters. Often things are clusters an akshara depending on whether they’re drawn with an explicit virama or form a single glyph.
In general the nature of the virama as a two-way combining character in Unicode is pretty new.
## Hangul
Korean does its own fun thing when it comes to conjoining characters. Hangul has a concept of a “syllable block”, which is basically a letter. It’s made up of a leading consonant, medial vowel, and an optional tail consonant. 각 is an example of such a syllable block, and it can be typed as ᄀ + ᅡ + ᆨ. It can also be typed as 각, which is a “precomposed form” (and a single code point).
These characters are examples of combining characters with very specific combining rules. Unlike accents or other diacritics, these combining characters will combine with the surrounding characters only when the surrounding characters form an L-V-T or L-V syllable block.
As I mentioned in my previous post, apparently syllable blocks with more (adjacent) Ls, Vs, and Ts are also valid and used in Old Korean, so the grapheme segmentation algorithm in Unicode considers “ᄀᄀᄀ각ᆨᆨ” to be a single grapheme (it explicitly mentions this). I’m not aware of any fonts which render these as a single syllable block, or if that’s even a valid thing to do.
## Han scripts
So Chinese (Hanzi), Japanese (Kanji1), Korean (Hanja2), and Vietnamese (Hán tự, along with Chữ Nôm 3) all share glyphs, collectively called “Han characters” (or CJK characters4). These languages at some point in their history borrowed the Chinese writing system, and made their own changes to it to tailor to their needs.
Now, the Han characters are ideographs. This is not a phonetic script; individual characters represent words. The word/idea they represent is not always consistent across languages. The pronounciation is usually different too. Sometimes, the glyph is drawn slightly differently based on the language used. There are around 80,000 Han ideographs in Unicode right now.
The concept of ideographs itself breaks some of our Latin-1 assumptions. For example, how do you define Levenshtein edit distance for text using Han ideographs? The straight answer is that you can’t, though if you step back and decide why you need edit distance you might be able to find a workaround. For example, if you need it to detect typos, the user’s input method may help. If it’s based on pinyin or bopomofo, you might be able to reverse-convert to the phonetic script, apply edit distance in that space, and convert back. Or not. I only maintain an idle curiosity in these scripts and don’t actually use them, so I’m not sure how well this would work.
The concept of halfwidth character is a quirk that breaks some assumptions.
In the space of Unicode in particular, all of these scripts are represented by a single set of ideographs. This is known as “Han unification”. This is a pretty controversial issue, but the end result is that rendering may sometimes be dependent on the language of the text, which e.g. in HTML you set with a <span lang=whatever>. The wiki page has some examples of encoding-dependent characters.
Unicode also has a concept of variation selector, which is a code point that can be used to select between variations for a code point that has multiple ways of being drawn. These do get used in Han scripts.
While this doesn’t affect rendering, Unicode, as a system for describing text, also has a concept of interlinear annotation characters. These are used to represent furigana / ruby. Fonts don’t render this, but it’s useful if you want to represent text that uses ruby. Similarly, there are ideographic description sequences which can be used to “build up” glyphs from smaller ones when the glyph can’t be encoded in Unicode. These, too, are not to be rendered, but can be used when you want to describe the existence of a character like biáng. These are not things a programmer needs to worry about; I just find them interesting and couldn’t resist mentioning them :)
Japanese speakers haven’t completely moved to Unicode; there are a lot of things out there using Shift-JIS, and IIRC there are valid reasons for that (perhaps Han unification?). This is another thing you may have to consider.
Finally, these scripts are often written vertically, top-down. Mongolian, while not being a Han script, is written vertically sideways, which is pretty unique. The CSS writing modes spec introduces various concepts related to this, though that’s mostly in the context of the Web.
## Thai / Khmer / Burmese / Lao
These scripts don’t use spaces to split words. Instead, they have rules for what kinds of sequences of characters start and end a word. This can be determined programmatically, however IIRC the Unicode spec does not attempt to deal with this. There are libraries you can use here instead.
## Latin scripts themselves!
Turkish is a latin-based script. But it has a quirk: The uppercase of “i” is a dotted “İ”, and the lowercase of “I” is “ı”. If doing case-based operations, try to use a Unicode-aware library, and try to provide the locale if possible.
Also, not all code points have a single-codepoint uppercase version. The eszett (ß) capitalizes to “SS”. There’s also the “capital” eszett ẞ, but its usage seems to vary and I’m not exactly sure how it interacts here.
While Latin-1 uses precomposed characters, Unicode also introduces ways to specify the same characters via combining diacritics. Treating these the same involves using the normalization algorithms (NFC/NFD).
## Emoji
Well, not a script5. But emoji is weird enough that it breaks many of our assumptions. The scripts above cover most of these, but it’s sometimes easier to think of them in the context of emoji.
The main thing with emoji is that you can use a zero-width-joiner character to glue emoji together.
For example, the family emoji 👩👩👧👦 (may not render for you) is made by using the woman/man/girl/boy emoji and gluing them together with ZWJs. You can see its decomposition in uniview.
There are more sequences like this, which you can see in the emoji-zwj-sequences file. For example, MAN + ZWJ + COOK will give a male cook emoji (font support is sketchy). Similarly, SWIMMER + ZWJ + FEMALE SIGN is a female swimmer. You have both sequences of the form “gendered person + zwj + thing”, and “emoji containing human + zwj + gender”, IIRC due to legacy issues6
There are also modifier characters that let you change the skin tone of an emoji that contains a human (or human body part, like the hand-gesture emojis) in it.
Finally, the flag emoji are pretty special snowflakes. For example, 🇪🇸 is the Spanish flag. It’s made up of two regional indicator characters for “E” and “S”.
Unicode didn’t want to deal with adding new flags each time a new country or territory pops up. Nor did they want to get into the tricky business of determining what a country is, for example when dealing with disputed territories. So instead, they just defined these regional indicator symbols. Fonts are supposed to take pairs of RI symbols7 and map the country code to a flag. This mapping is up to them, so it’s totally valid for a font to render a regional indicator pair “E” + “S” as something other than the flag of Spain. On some Chinese systems, for example, the flag for Taiwan (🇹🇼) may not render.
I hightly recommend comparing against this relatively small list of scripts the next time you are writing code that does heavy manipulation of user-provided strings.
1. Supplemented (but not replaced) by the Hiragana and Katakana phonetic scripts. In widespread use.
2. Replaced by Hangul in modern usage
3. Replaced by chữ quốc ngữ in modern usage, which is based on the Latin alphabet
4. “CJK” (Chinese-Japanese-Korean) is probably more accurate here, though it probably should include “V” for Vietnamese too. Not all of these ideographs come from Han; the other scripts invented some of their own. See: Kokuji, Gukja, Chữ Nôm.
5. Back in my day we painstakingly typed actual real words on numeric phone keypads, while trudging to 🏫 in three feet of ❄️️, and it was uphill both ways, and we weren’t even allowed 📱s in 🏫. Get off my lawn!
6. We previously had individual code points for professions and stuff and they decided to switch over to using existing object emoji with combiners instead of inventing new profession emoji all the time
7. 676 countries should be enough for anybody | {"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": 0.4428098797798157, "perplexity": 2590.543140993194}, "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/1495463607325.40/warc/CC-MAIN-20170523025728-20170523045728-00366.warc.gz"} |
http://mathsci.kaist.ac.kr/home/schedul/seminar/?idx=-1844 | # 세미나 및 콜로퀴엄
2017-03
Sun Mon Tue Wed Thu Fri Sat
1 2 3 4
5 6 7 2 8 9 1 10 1 11
12 13 14 15 1 16 1 17 18
19 20 21 22 2 23 1 24 25
26 27 28 29 30 1 31 1
2017-05
Sun Mon Tue Wed Thu Fri Sat
1 2 3 4 5 6
7 8 9 10 11 1 12 1 13
14 15 16 17 18 19 20
21 22 23 24 25 2 26 27
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구글 Calendar나 iPhone 등에서 구독하면 세미나 시작 전에 알림을 받을 수 있습니다.
재미로 풀어보는 퀴즈에나 등장할 법한 추상적인 수학적 개념이 기계공학(예, 응용역학) 연구에 도움을 줄 수 있을까? 수학과 역학 사이의 간극이 가장 좁았던 때는 언제였고, 수학과 역학이 만나는 지점에서 두 학문을 두루 섭렵했던 수리과학자는 누구였을까? 이와 같은 질문에 대한 답변의 일환으로, 본 발표의 전반부에서는 수학과 역학(유체역학, 고체역학, 열역학, 파동학)의 역사가 공존했던 시절을 인물 중심으로 살펴보고자 한다. 본 발표의 후반부에서는, 역학적 파동과 메타물질에 관한 발표자의 연구주제(음향 투명망토, 음향 블랙홀, 생물음향학 등)를 간략하게 소개한다.
Host: 임미경 한국어 2017-02-21 12:27:23
2017 제1회 정오의 수학산책
강연자: 한종규 (서울대)
일시: 2017년 3월 31일(금) 12:00 ~ 13:15
장소: 카이스트 자연과학동 E6-1 3435호
제목: Symmetry, invariants and conservation laws
내용: The notion of symmetry plays a central role in understanding natural laws and in solving equations. To be symmetric means to be invariant under a group action. In this lecture we are mainly concerned with continuous groups of the symmetries of differential equations. I will explain Sophus Lie's ideas on solvability of an ordinary differential equation in terms of its symmetry group and Emmy Noether's theorem on conservation laws for variational problems. As time permits I will present other viewpoints on the conservation laws.
등록: 2017년 3월 29일(수) 오후 3시까지
문의: hskim@kias.re.kr / 내선:8545
Host: 이지운 미정 2017-02-28 16:08:42
Among the most well-known examples of L-functions are the Riemann zeta
function and the L-functions associated to classical modular forms.
Less well known, but equally important, are the L-functions associated
to Maass forms, which are eigenfunctions of the Laplace-Beltrami
operator on a hyperbolic surface. Named after H. Maass, who discovered
some examples in the 1940s, Maass forms remain largely mysterious.
Fortunately, there are concrete tools to study Maass forms: trace
formulas, which relate the spectrum of the Laplace operator on a
hyperbolic surface to its geometry. After Selberg introduced his
famous trace formula in 1956, his ideas were generalised, and various
trace formulas have been constructed and studied. However, there are
few numerical results from trace formulas, the main obstacle being
their complexity. Various types of trace formulas are investigated,
constructed and used to understand automorphic representations and
their L-functions from a theoretical point of view, but most are not
explicit enough to implement in computer code.
Having explicit computations of trace formulas makes many potential
applications accessible. In this talk, I will explain the
computational aspects of the Selberg trace formula for GL(2) for
general levels and applications towards the Selberg eigenvalue
conjecture and classification of 2-dimensional Artin representations
of small conductor.
This is a joint work with Andrew Booker and Andreas Strömbergsson.
Host: 임보해 영어 2017-03-02 11:08:35
미정 2017-02-21 12:32:16
미정 2017-01-16 13:27:46
In this talk, we summarize results concerning anomalous behaviour of random walks and diffusions in disordered media. Examples of disordered media include fractals and various models of random graphs, such as percolation clusters, random conductance models, ErdH{o}s-R'enyi random graphs and uniform spanning trees.
Geometric properties of such disordered media have been studied extensively and their scaling limits have been obtained. Our focus here is to analyze properties of dynamics in such media. Due to the inhomogeneity of the underlying spaces, we observe anomalous behaviour of the heat kernels and obtain anomalous diffusions as scaling limits of the random walks. We will give a chronological overview of the related research, and describe how the techniques have developed from those introduced for exactly self-similar fractals to the more robust arguments required for random graphs.
Host: 폴정 영어 2017-02-21 12:35:16
2017 제2회 정오의 수학산책
강연자: 이윤원 (인하대)
일시: 2017년 4월 28일(금) 12:00 ~ 13:15
장소: 카이스트 자연과학동 E6-1 3435호
제목: Atiyah-Singer index theorem
내용: TBA
등록: 2017년 4월 26일(수) 오후 3시까지
문의: hskim@kias.re.kr / 내선:8545
Host: 이지운 한국어 2017-02-28 16:12:46
This talk will review previous work on quadrupedal gaits and recent work on a generalized model for binocular rivalry proposed by Hugh Wilson. Both applications show how rigid phase-shift synchrony in periodic solutions of coupled systems of differential equations can help understand high level collective behavior in the nervous system.
Host: 김재경 영어 2017-02-21 12:38:07
2017 제3회 정오의 수학산책
강연자: 이수준(경희대)
일시: 2017년 5월 12일(금) 12:00 ~ 13:15
장소: 카이스트 자연과학동 E6-1 3435호
제목: 양자정보이론 소개 : 디지털정보 vs 양자정보
내용: TBA
등록: 2017년 5월 10일(수) 오후 3시까지
문의: hskim@kias.re.kr / 내선:8545
Host: 이지운 한국어 2017-02-28 16:16:01
In the talk, I discuss previous works on the arithmetic of various twisted special $L$-values and dynamical phenomena behind them. Main emphasis will be put on the problem of estimating several exponential sums such as Kloosterman sums and its relation to the problem of non-vanishing of special $L$-values with cyclotomic twists. A distribution of homological cycles on the modular curves will also be discussed and as a consequence, some results on a conjecture of Mazur-Rubin-Stein about the distribution of period integrals of elliptic modular forms will be presented.
미정 2017-01-16 13:37:22
Host: 임보해 미정 2017-02-21 12:40:27
미정 2017-01-16 13:49:23
The Siegel series is the local factor of the Fourier coefficient of the Siegel-Eisenstein series. It is also a crucial ingredient in Kudla's program to compare it with intersection numbers.
In this talk, I will explain a conceptual reformulation of the Siegel series. As the first application, I will explain a conceptual (and simple) proof of the equality between intersection number and the (derivative of) Siegel series. As the second application, I will explain a newly discovered identity between them. This is a joint work with T. Yamauchi.
Host: 임보해 미정 2017-02-10 12:42:59
There is a classical result first due to Keen known as the collar lemma for hyperbolic surfaces. A consequence of the collar lemma is that if two closed curves A and B on a closed orientable hyperbolizable surface have non-zero geometric intersection number, then there is an explicit lower bound for the length of A in terms of the length of B, which holds for any hyperbolic structure on the surface. By slightly weakening this lower bound, we generalize this statement to hold for all Hitchin representations. This is a joint work with Tengren Zhang.
Host: 백형렬 영어 2017-03-09 09:30:25
Many problems in control and optimization require the treatment
of systems in which continuous dynamics and discrete events
coexist. This talk presents a survey on some of our recent work on such
systems. In the setup, the discrete event is given by a random
process with a finite state space, and the continuous component is the
solution of a stochastic differential equation. Seemingly similar
to diffusions, the processes have a number of salient features
distinctly different from diffusion processes. After providing
motivational examples arising from wireless communications,
identification, finance, singular perturbed Markovian systems,
manufacturing, and consensus controls, we present necessary and
sufficient conditions for the existence of unique invariant
measure, stability, stabilization, and numerical solutions of
control and game problems.
Host: 김재경 영어 2017-02-21 12:23:17
Originated from applications in signal processing, random evolution,
telecommunications, risk management, financial engineering,
and manufacturing systems, two-time-scale Markovian systems have
drawn much attention. This talk discusses asymptotic
expansions of solutions to the forward equations, scaled and unscaled
occupation measures, approximation error bounds, and associated
switching diffusion processes. Controlled dynamic systems will also
be mentioned.
Host: paul jung 영어 2017-02-21 13:21:06
1952년 영국의 수학자 A. Turing은 그 당시 생물학자들 조차 전혀 상상 할수 없었던, 다 같은 종류의 세포들이 각자 다른 세포로 분화할수 있는 메커니즘을 Reaction-Diffusion System(RD system)을 이용하여 수학적으로 제시했습니다. 그 이후로, RD system은 수리해석학적으로도 많은 발전을 거듭해왔으며, 수리모델링을 통해 생명과학 분야에 있어서도 생명의 메커니즘을 밝히는 도구로서 발전을 거듭해 오고 있습니다.
이 강연에서는 제가 최근에 연구를 진행하고 있는 다양한 생명현상을 예로 그 메커니즘을 밝히기 위해 개발한 수리모델 및 수리모델링 수법을 간단하게 소개하겠습니다. 여기에는 수학적으로 재미있는 구조를 가지고 있을 지 모르는 문제들이 숨어 있을 수 있습니다. 그런 문제들을 여러분들께서 직접 찾아 보시길 바랍니다.
Keywords: Mathematical modeling, PDE, Phase-field method
Host: 변재형 한국어 2017-03-08 13:41:27
Liquid crystal is a state of matter between isotropic fluid and crystalline solid, which has properties of both liquid and solid. In a liquid crystal phase, molecules tend to align a preferred direction and molecules are described by a symmetric traceless 3x3 matrix which is often called a second order tensor. Equilibrium states are corresponding to minimizers of the governing Landau-de Gennes energy which plays an important role in mathematical theory of liquid crystals. In this talk, I will present a brief introduction to Landau-de Gennes theory and recent development of mathematical theory together with interesting mathematical questions.
Host: 권순식 영어 2017-02-21 12:07:17
A well known theorem of Grötzsch states that every planar graph is 3-colorable. We will show a simple proof based on a recent result of Kostochka and Yancey on the number of edges in 4-critical graphs. Then we show a strengthening of the Grötzsch’s theorem in several different directions. Based on joint works with Ilkyoo Choi, Jan Ekstein, Zdeněk Dvořák, Přemek Holub, Alexandr Kostochka, and Matthew Yancey.
Host: 최일규 엄상일 미정 2017-03-02 09:10:53
Consider a simple symmetric random walk $S$ and another random walk $S'$ whose $k$th increments are the $k$-fold product of the first $k$ increments of $S$.
The random walks $S$ and $S'$ are strongly dependent. Still the 2-dimensional walk $(S, S')$, properly rescaled, converges to a two dimensional Brownian motion. The goal of this talk is to present the proof of this fact, and its generalizations. Based on joint works with K. Hamza and S. Meng.
Host: paul jung 영어 2017-02-21 14:37:05 | {"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": 0.7622526288032532, "perplexity": 8050.371766648406}, "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/1490218189472.3/warc/CC-MAIN-20170322212949-00223-ip-10-233-31-227.ec2.internal.warc.gz"} |
http://consequently.org/news/2009/06/02/Rumfitt_Part_2/ | ## Rumfitt on Multiple Conclusions, Part 2
#### June 2, 2009
This is Part 2 of a series of comments on Ian Rumfitt’s paper “Knowledge by Deduction” (Grazer Philosophische Studien, vol. 77 (2008) pp. 61–84). In Part 1, I focussed on Rumfitt’s direct criticism of my approach in “Multiple Conclusions,” and I tried to show that his criticism missed the mark, and that it missed the mark in an important way. The norms of logical consequence and logical coherence apply not only to occurrent beliefs but to all manner of states of accepting and rejecting (or acts of assertion and denial), whether they express our deep standing beliefs or hypotheses we simply entertain lightly.
In this part, I want to consider the comments on the possibility of genuine proofs with multiple conclusions.
Rumfitt writes (and I’ll quote him at some length here), on page 79:
The rarity, to the point of extinction, of naturally occurring multiple-conclusion arguments has always been the reason why mainstream logicians have dismissed multiple-conclusion logic as little more than a curiosity. (See e.g. Tennant 1997, 320.) And attempts by enthusiasts to alleviate the embarrassment here have often ended up compounding it. In the introduction to their textbook on the subject, Shoesmith and Smiley concede that multiple-conclusion proofs can scarcely be said to form part of the everyday repertoire of mathematics. ‘Perhaps the nearest one comes to them’, they go on, “is in proof by cases, where one argues “suppose A1 then B; … suppose Am then B; but A1 ∨ … ∨ Am, so B”. A diagrammatic representation of this argument exhibits the downward branching which we shall see is typical of formalised multiple-conclusion proofs … But the ordinary proof by cases is at best a degenerate form of multiple-conclusion argument, for the different conclusions are all the same (in our example they are all instances of the same formula B)” (Shoesmith and Smiley 1978, 4–5). “At best degenerate”, though, hardly says it. I do not know how the word “multiple” is used in Cambridge, but in the rest of the English-speaking world it is understood to mean “more than one”. So an example of an argument in which all the conclusions (sic) are identical provides little justification for taking multiple-conclusion logic seriously. But since this is all that Shoesmith and Smiley provide by way of a positive case for deeming their system to be a branch of logic, readers of their book may be forgiven for closing it with a sigh on reaching p. 5 of the introduction.
What can I say about that?
First of all, in defence of Shoesmith and Smiley, the one example of proof by cases (in which the intermediate formula are all the same) is not the only consideration they provide in favour of taking their system to be a branch of logic. Showing that it is a codification of a notion of (let’s call it) quasi-proof which delivers logical consequence on Gentzen’s sequents, and which, when restricted to single conclusion deductions agrees with traditional natural deduction should count for something. If it’s not a branch of logic, what is it?
To be sure, a single case where the only multiple conclusions aren’t very multiple is not very satisfying. But there is a genuine sense, of course, in which even in this case the conclusions are multiple. Surely they have heard of the type–token distinction outside of Cambridge? There is a perfectly admissible sense in which the rule of conjunction introduction (in Gentzen’s natural deduction) requires two premises, even when the instance used is a derivation of PP from the premises P and P. (To rewrite this to be a proof from one instance of P to PP may radically change the structure of the proof, especially if both instances of P are proved in very different ways.)
But that is a minor point, not worth any more of our time. More important is the way that Rumfitt missed what is going on in proofs by cases. I don’t mind that he missed my example of a proof featuring multiple conclusions, discussed in “Multiple Conclusions” on page 199 to address just the point Rumfitt raised here.
Suppose everyone is either happy or tired. Choose a person. It follows that this person is either happy or tired. There are two cases. Case (i) this person is happy. Case (ii) this person is tired, and as a result someone is tired. As a result, either this person is happy or someone (namely that person) is tired. But the person we chose was arbitrary, so either everyone is happy or someone is tired.
This seems to me to be perfectly valid reasoning: It’s a proof. It’s a renderng in (somewhat) natural language of a sequent derivation of “everything is an F or something is a G” from “everything is either F or G.” (For the sequent derivation I used, see the paper.)
In this proof, there are two conclusions active at a number of points. Stop the proof before the sentence starting “As a result”. Consider the state of play at this point in the derivation. We have a proof from “Everyone is either happy or tired” to the two conclusions: “Case (i) a is happy.” (where a is an eigenvariable standing for ‘that person’, which in turn points back to the choice made after the supposition.) “Case (ii) someone is tired.” In other words, we have a proof corresponding to the sequent (everything is either F or GFa, something is G.)
I cannot think of any way of understanding the deduction up to that point in such a way as to (a) see it as a single deduction, and (b) not introduce irrelevant connectives not explicitly used in the text. This example seems to me to be strong evidence that one can find in nature real-life uses of multiple conclusions in action, if you know where to look.
If you know where to look, you know that you don’t need tricky cases of intuitionistically invalid arguments to make the point. The point is there in Shoesmith and Smiley’s own examples of proof by cases. If you stop a proof by cases (in the middle of the ellipses eliding the interesting bits of the subproofs, in the bit of Shoesmith & Smiley quoted by Rumfitt) you will get more interesting cases where the conclusions in play differ. For example, take this proof of (pq) ∨ (pr) from p ∧ (qr). (Ignore the bracketed markers [a], [b] and [c] for the moment.)
Suppose p ∧ (qr). Then it follows that p. It follows that qr. So, we have two cases: (i) q, and (ii) r. [a] Consider case (i). Here, q, and we already have p, so pq. Consider case (ii). Here, r, and we already have p, so pr. [b]. Back in case (i), it follows that (pq) ∨ (pr). In (ii), it also follows that (pq) ∨ (pr) [c]. So, we conclude, (pq) ∨ (pr).
Again, this seems to me to be perfectly understandable reasoning. The point at which Rumfitt jokes about ‘multiple’ instances of the conclusion B corresponds to our point [c], where we have proved the conclusion (pq) ∨ (pr) in each case, but have not yet drawn them together to a single conclusion in the argument. True, at this point we have a proof with two instances of the one concluding formula. This is no better or worse than a proof with two instances of the one premise formula.
But [c] is only one place to stop the proof. Suppose we pause at point [b]. What do we have there? It’s a proof from one premise p ∧ (qr), leading to two cases, one in which we’ve proved pq, and the other in which we’ve proved pr. This corresponds to the sequent p ∧ (qr) ⇒ pq, pr, and the two concluding formulas are different.
Now, let me confess: I engineered this case by interleaving the two cases in the text, to get to an intermediate step in both of them. But this does not render the case any less salient. I could have stopped at point [a], and here, what we have got to is a sequent p ∧ (qr) ⇒ q, r. In other words, we have just got to the point at which the disjunction is broken up into two cases, and each case is ready for further processing using the rules.
That is the core idea of multiple conclusion natural deduction. The disjunction rule can be understood simply, as taking us from pq to the two conclusions p, q, which can then be operated on as usual, in the one proof. If you don’t like this, that’s fine. However, that is not an argument to the effect that multiple conclusion structures can’t be found in natural reasoning. They are there if you know where to look.
In a few days I’ll post a response to what I take to be the most interesting of Rumfitt’s arguments, his considerations against the Cut Rule. But that, I suspect, will take a little more time, and other duties are pressing for the next few days.
As ever, comments on these ideas are most welcome.
← Rumfitt on Multiple Conclusions, Part 1 | News Archive | Live from Hejnice → | {"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": 0.84394770860672, "perplexity": 985.9164654252518}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-17/segments/1492917120844.10/warc/CC-MAIN-20170423031200-00400-ip-10-145-167-34.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/damped-harmonic-motion.683627/ | # Damped Harmonic Motion
1. Apr 6, 2013
### elemis
So my professor was discussing the case of a mass suspended from a vertical massless spring in some viscous liquid.
He arrives at the equation of motion which was :
x: + $\frac{b}{m}$x. + $\frac{k}{m}$x = 0
x: is the second derivative of displacement wrt time. similarly x. is the first derivative.
He then defined b/m = gamma k/m= w^2
He then used the trial solution x=$Ae^{t\tau}$ formed an auxillary equation and solved it to get :
$\frac{-\gamma}{2}$±$\sqrt{\frac{\gamma^2}{4}-w^2}$
He then examined the discriminant of the above equation to formulate the general solution for light damping.
I understand in light damping w^2 < (gamma^2)/4
But how does he arrive at the following general solution :
$Ae^\frac{t\gamma}{2}cos(wt + \phi)$
Where did the e^t*gamma/2 come from ? Why is there no sine function even though we have an imaginary root case ? Why is there a phi in there ?
2. Apr 6, 2013
3. Apr 6, 2013
### elemis
I dont understand what you mean. Can you be more specific ?
4. Apr 6, 2013
### Shinobii
The $\phi$ has essentially absorbed the Sine term. It is just another way to rewrite the more general solution (Which involves both Cosine + Sine functions). The exponential comes from the solution to the differential equations. If you understand the differential equation, everything will make complete sense.
I hope I am shedding some light on the matter and not digging you a deeper hole. . .
This is thoroughly explained in any 2nd year classical mechanics or quantum mechanics text.
5. Apr 6, 2013
### WannabeNewton
Hi elemis. You have to be a little careful with the notation there. So for the lightly damped case, the two roots we get are given by $$r_1 = -\frac{\gamma}{2} + i\sqrt{\omega_{n}^{2} - \frac{\gamma^{2}}{4}}, r_2 = -\frac{\gamma}{2} - i\sqrt{\omega_{n}^{2} - \frac{\gamma^{2}}{4}}$$ where $\omega_{n}$ is the natural frequency. So the solution in the complex plane is going to be $$r(t) = c_1e^{-\frac{\gamma}{2} + i\sqrt{\omega_{n}^{2} - \frac{\gamma^{2}}{4}}t} + c_2e^{-\frac{\gamma}{2} - i\sqrt{\omega_{n}^{2} - \frac{\gamma^{2}}{4}}t} = e^{-\gamma/2}(c_1e^{i\sqrt{\omega_{n}^{2} - \frac{\gamma^{2}}{4}}t} + c_2e^{- i\sqrt{\omega_{n}^{2} - \frac{\gamma^{2}}{4}}t})$$ We then define the damped frequency $\omega_{d}:= \sqrt{\omega_{n}^{2} - \frac{\gamma^{2}}{4}}$. Then, $r(t) = e^{(-\gamma/2)t}(c_1e^{i\omega_{d}t} + c_2e^{- i\omega_{d}t})$ so if we take the real part of this we get our response $x(t) = e^{(-\gamma/2)t}(c_1\cos\omega_{d}t + c_2\sin\omega_{d}t)$. We can rewrite this as $x(t) = Ae^{(-\gamma/2)t}\cos(\omega_{d}t - \phi)$, after defining $A = \sqrt{c_{1}^2 + c_{2}^2}, \phi = \arctan(c_{2}/c_{1})$ and using the cosine addition formulas.
Last edited: Apr 6, 2013
6. Apr 6, 2013
### AlephZero
Are you sure about that? You can do the math that way, but the end result is messy (as in Wannabenewton's post).
Things work out a lot nicer if you define $k/m = \omega^2$ and then $b/m = \gamma \omega$. $\gamma$ is then dimensionless (just a number).
(In fact if you define $b/m = 2 \beta \omega$ the math works out even nicer still).
7. Apr 6, 2013
### WannabeNewton
This was the way my professor defined it in fact. I do agree it works out nicer and it's less work for me since I don't have to change the terms in my notes when posting here :tongue2:
8. Apr 6, 2013
### AlephZero
The only problem is that some computer systems for dynamics analysis include the "2" and others don't.
But in real life, you often don't know the level of damping to within a factor of 2, so it might not make much difference either way | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 2, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9640288949012756, "perplexity": 630.1704712888585}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257647322.47/warc/CC-MAIN-20180320072255-20180320092255-00271.warc.gz"} |
http://www.math-only-math.com/worksheet-on-telling-time.html | # Worksheet on Telling Time
Math worksheet on telling time will help us to practice the questions on how to tell time.
1. Fill in the blanks by choosing the correct time from the brackets:
(a) Ron eats lunch at _____________ (2 : 30 a.m. / 2 : 30 p.m.)
(b) The sun rises at _____________ (5 : 30 a.m. / 5 : 30 p.m.)
(c) Eva eats dinner at _____________ (8 : 30 a.m. / 8 : 30 p.m.)
(d) Nancy's school starts at _____________ (7 : 30 a.m. / 7 : 30 p.m.)
2. Write the time using a.m. / p.m.:
(a) 6:10 in the evening _____________
(b) 9 o'clock in the morning _____________
(c) 4 hours after midnight _____________
(d) 3 hours before noon _____________
(e) 1 hour before midnight _____________
(f) 1 hour after noon _____________
3. Write the lime 3 hours after :
(a) 8 : 15 p.m.
(b) 10 : 20 a.m.
(c) midnight
(d) 11 : 15 p.m.
4. Write the time 3 hours before:
(a) noon
(b) 2 : 05 a.m.
(c) 1 : 15 p.m.
(d) 4 : 45 p.m.
5. Sam and Ken went to see a movie. It was 2 hours 15 minutes long. The show began at 6 : 15 p.m. What time will it get over?
6. Ken's school begins at 7 : 55. He wants to reach 45 minutes before school begins so that he can play with his friends. At what time should Ken reach school?
7. Andy is lined up for his first marathon. At 5 : 45 a.m. the whistle blows and the race begins.
Solve the problems given:
(a) Andy reaches the first refreshment stall at 6 : 05 a.m. How long has he been running?
(b) He reaches the next refreshment stall at 6 : 25 a.m. How long has it taken Andy to run from stall 1 to stall 2.
(c) At 6: 50 a.m. Akhil catches up with Andy near the 6 km mark. How long has Andy taken to run the first 6 km of the race?
(d) Andy reaches the 12 km mark at 7 : 55 a.m. How long has he been running? Did he run the first 6 km of the race faster or slower than the second 6 km of the race? By how much time?
(e) Andy slows down for the next two km. He reaches the 14 km mark at 8 : 45 a.m. How long did it take him to run these two km.
(f) Andy finished the race in 4 hours, 15 minutes. At what time did he cross the finish line?
(g) The organizers of the race were at their posts from 5 a.m. to 4 : 45 p.m. How long were they at their posts?
Answers for the worksheet on telling time will help us to check the answers given below.
1. (a) 2 : 30 am
(b) 5 : 30 am
(c) 8 : 30 pm
(d) 7 : 30 am
2. (a) p.m.
(b) a.m.
(c) a.m.
(d) a.m.
(e) p.m.
(f) p.m.
3. (a) 11 : 15 p.m.
(b) 1 : 20 p.m.
(c) 3 : 00 a.m.
(d) 2 : 15 a.m.
4. (a) 9 : 00 a.m.
(b) 11 : 05 p.m.
(c) 10 : 15 a.m.
(d) 1 : 45 p.m.
5. 8 : 30 p.m
6. 7 : 10 a.m.
7. (a) 20 minutes
(b) 20 minutes
(c) 1 hour 5 minutes
(d) 2 hours 10 minutes, same
(e) 50 minutes
(f) 12 : 10
(g) 11 hours 15 minutes | {"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": 0.3445180654525757, "perplexity": 3658.8490298631764}, "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/1531676590074.12/warc/CC-MAIN-20180718080513-20180718100513-00145.warc.gz"} |
https://sbainvent.com/dynamics/kinetics-force-acceleration-of-a-particle/friction-2/ | # Friction
Friction is a resistance cause by two objects dragging across each other. There are several types of situations that can cause friction. However, for right now I am only going to discuss dry friction, since this is most likely the type of friction that you will encounter in dynamics problems. When analyzing dry friction you need to realize the cause of friction is at the microscopic level. As a result if you drag two objects across each these microscopic imperfection will catch on each other causing a resultant force. In turn the rougher the surface the greater the frictional force.
### Static and Kinetic Friction
There are two basic types of dry friction; static and kinetic friction. First, let’s talk about static friction. Static friction is ability the object has to resist movement. Once a force that is greater than this force acts on the body it will start to move.
(Eq 1) $f=μ_sW,μ_s=coefficient~of~static~friction$
On the other hand what happens once the object starts to move? Well, since you will still feel a resistance when pulling a moving object that means friction is still present. In this case it is kinetic friction. The force caused by kinetic friction is always lower than the force caused by static friction.
(Eq 2) $f=μ_kW,μ_k=coefficient~of~kinetic~friction$
### Laws of Friction
There are three laws that describe dry friction. They are as follows.
-Amontons’ First Law: “The force of friction is directly proportional to the applied load.”
This means that applied load that is perpendicular to the contact surface will generate frictional force that is proportional to that load.
-Amontons’ Second Law: “The force of friction is independent of the apparent area of contact.”
This means that regardless of how large or small an objects contact area is the frictional forces will remain the same.
-Coulomb’s Law of Friction: “Kinetic friction is independent of the sliding velocity.
This means that regardless of how fast or slow an object is moving the force caused by kinetic friction will remain the same.
### Coefficients of Friction of Certain Materials
Materials in Contact Static Friction Kinetic Friction Dry and Clean Lubricated Dry and Clean Lubricated Aluminum Aluminum 1.10-1.35 0.30 1.5 – Aluminum Steel 0.61 – 0.47 – Steel Steel 0.80 0.16 0.42-0.62 Brass Steel 0.50 0.19 0.44 – Steel Teflon 0.04-0.2 0.04 – 0.04 Copper Steel 0.53 – 0.36 –
### Example
A box is being pulled by rope. The coefficient of static friction is 0.26. The rope will fail at 450lb. How heavy can the box be before the rope fails?
### Solution
Step 1: Draw a Free Body Diagram to see how the forces are acting on the box.
$F$ = Frictional Force
$P$ = Force on the box
$N$ = Force the ground is pushing on the box
$W$ = Weight of the box
Step 2: Relate the frictional force to the force on the rope.
$F=P=Wμ_s$
$450 = W(0.26)$
$W = 1730.8~lb$
##### Other Types of Friction
As mentioned above there are other types of friction that can occur. They are as follows. Fluid friction is resistance between the layers of viscous fluid as the fluid is moving. Fluid friction is what creates boundary layers in a moving fluid. In addition, another type of friction is lubricated friction. Lubricated friction is the resulting friction as two solid bodies move against each other when there is a layer of lubricant between the two objects. Skin friction is another type of friction which defines drag as a fluid moves across a solid bodies surface. Finally, internal friction is a force that occurs between the elements that make up a solid body as it is deforming.
Looking at thermodynamics, as two objects move against each other the friction that they create will convert kinetic energy in thermal energy. In other words work is being converted into heat. This results in a loss in performance, since energy that was meant to be used for work has been lost to heat. Friction can also cause premature wear on parts. Due to these two facts it is best to try to minimize friction as much as possible. However, friction will always be present to some extent.
| | {"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": 0.42598095536231995, "perplexity": 869.7244657893718}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-51/segments/1544376823872.13/warc/CC-MAIN-20181212112626-20181212134126-00278.warc.gz"} |
https://yugeten.github.io/year-archive/ | Published:
# Before diving in
For a long time, I recall having this vague impression about Gaussian Processes (GPs) being able to magically define probability distributions over sets of functions, yet I procrastinated reading up about them for many many moons. However, as always, I’d like to think that this is not just due to my procrastination superpowers. Whenever I look up “Gaussian Process” on Google, I find these well-written tutorials with vivid plots that explain everything up until non-linear regression in detail, but shy away at the very first glimpse of any sort of information theory. The key takeaway is always,
A Gaussian process is a probability distribution over possible functions that fit a set of points. | {"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": 0.8801195025444031, "perplexity": 562.6413782062748}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540511946.30/warc/CC-MAIN-20191208150734-20191208174734-00068.warc.gz"} |
https://quant.stackexchange.com/questions/39584/independence-of-initial-wealth-for-constant-absolute-risk-aversion | # Independence of initial wealth for Constant Absolute Risk Aversion
Suppose a consumer's preference over wealth gambles (lotteries) can be represented by a twice differentiable Von Neumann Morgenstern utility function. Show that the consumer's preference over gambles are independent of his initial wealth if and only if his utility function displays Constant Absolute Risk Aversion (CARA).
• please if someone knows how to prove the question or if you know the link to get the solution help me – Fasiledes Fetene May 3 '18 at 8:42
• I'm voting to close this question as off-topic because this is unrelated to the field of quantitative finance. – Helin May 3 '18 at 8:43
Suppose a fair gamble pays $G = \pm \epsilon$ where $\displaystyle P(G=\epsilon ) = P(G = -\epsilon) = \frac{1}{2}$.
From the classic work described in
Pratt, J.W. (1964) "Risk-Aversion in the Small and in the Large'" Econometrica 55,143-54
for small gambles, the absolute amount an agent is willing to pay to avoid a gamble of a given size is determined by the coefficient of absolute risk aversion.
For a rough argument, we have a risk averse agent with initial wealth $W_0$ and utility function $U$ willing to pay $\delta$ to avoid the gamble such that $\delta$ is determined by
$$U(W_0 - \delta) = E[U(W_0+G)]=\frac{1}{2}U(W_0 +\epsilon) + \frac{1}{2}U(W_0- \epsilon).$$
Using the Taylor expansion for U around $W_0$ we have
$$U(W_0) -U'(W_0)\delta + \frac{1}{2} U''(W_0)\delta^2 + \ldots \\ = \frac{1}{2} [U(W_0) +U'(W_0)\epsilon + \frac{1}{2} U''(W_0)\epsilon^2 + \ldots ] \\ +\frac{1}{2} [U(W_0) -U'(W_0)\epsilon + \frac{1}{2} U''(W_0)\epsilon^2 + \ldots ] \\ = U(W_0) + \frac{1}{2}U''(W_0) \epsilon^2 + \ldots$$
Solving for $\delta$ for small $\epsilon$ we get
$$\delta \approx \frac{\epsilon^2}{2}\left[- \frac{U''(W_0)}{U'(W_0)} \right].$$
The premium to avoid a gamble is independent of initial wealth if and only if there is a constant $\gamma$ such that
$$- \frac{U''(W)}{U'(W)} = \gamma .$$
Solving this differential equation we get
$$U(W) = C_1 - e^{C_2} \frac{e^{-\gamma W}}{\gamma}.$$
Without loss of generality (from the invariance properties of utility functions) we can set $C_1 = C_2 = 0$ to obtain the CARA utility function
$$U(W) = - \frac{e^{-\gamma W}}{\gamma}.$$ | {"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": 0.8972418308258057, "perplexity": 563.1474553754637}, "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-2020-24/segments/1590347423915.42/warc/CC-MAIN-20200602064854-20200602094854-00236.warc.gz"} |
https://www.physicsforums.com/threads/finding-roots-of-equation-using-newtons-method.376451/ | # Homework Help: Finding roots of equation using Newtons method
1. Feb 8, 2010
### andrey21
1. Hi really struggling with this question any help would be great.
Use Newtons method to find the root of 4sin^2x - x = 0 which lies closest to x=2, correct to 3sf.
2. Relevant equations
3. The attempt at a solution
2. Feb 8, 2010
### HallsofIvy
The Newton-Raphson method starts with an initial value $x_0$ and then calculates a sequence $x_1$, $x_2$, ... using the formula
$$x_{n+1}= x_n- \frac{f(x_n)}{f'(x_n)}$$
Here $f(x)= 4sin^2(x)- x$ so $f'(x)= 8 sin(x)cos(x)- 1$
What initial value did you use and what results did you get?
3. Feb 8, 2010
### andrey21
Well I am at the same point now, however say i choose initial value of 1 when substituting into formula xn -(4sin^2x -x/ 8sinxcosx-1) my calculator is just saying error! is this because of the sin^2 part of the equation?
4. Feb 8, 2010
### D H
Staff Emeritus
Newton's method does not always converge. For example suppose somewhere along the line you get a value of xn that is close to a zero of the derivative function. This will send xn+1 into never-never land. This particular function, $$f(x)=4\sin^2(x)-x$$, has a very narrow interval of convergence wrt Newton's method. An initial value of 1 is outside that interval.
That said, you should be able to solve this equation without resorting to Newton's method. The convergence interval does contain this known point. Choose an initial value that is close to this known solution. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 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": 0.9361178278923035, "perplexity": 893.222630769206}, "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-2018-26/segments/1529267867885.75/warc/CC-MAIN-20180625131117-20180625151117-00085.warc.gz"} |
http://math.stackexchange.com/questions/200719/local-ring-of-variety-at-a-point | # Local ring of variety at a point
Let $X=V(xy) \subset \mathbb{C}^2$ be the affine algebraic set. (coordinate axes)
How can it be defined the local ring of $X$ at a point $P=(0,b)$ and $Q=(0,0)$?
My textbook only defines local ring for irreducible varieties. So I don't know the case of not irreducible sets.
I thought for $P$, $P$ is in $V(x)$ so the local ring of $V(x)$ at $P$. Is it right? But I have no ideas for the origin.
-
How does your textbook define the local ring for irreducible varieties? If you just change "irreducible variety" to "affine algebraic set" in the definition, does it still work? – Dustin Cartwright Sep 22 '12 at 14:53
The local ring really is a "local" property, so yes the local ring of $V(x)$ at $P$ is isomorphic to the local ring of $V(xy)$ at $P$. You might want to try calculating it both ways (see Dustin's comment) and check that you get the same thing. – Matt Sep 22 '12 at 14:55
My book's definition: the local ring of $V$ at a point $P$ is the ring of $f \in k(V)$ where $f$ is regular at $P$. (i.e. has a representation $f=g/h$ with $h(P) \neq 0$). – Gobi Sep 22 '12 at 15:14
So if I want to expand the definition, the field $k(V)$ is at first in trouble, since $k[V]$ is not an int dom. – Gobi Sep 22 '12 at 15:16
In general, the local ring at $Q$ in a Zariski-closed subset $X$ of $\mathbb{A}^n$ will be $k[x_1, \ldots, x_n] / I(X)$ localised at the maximal ideal $\mathfrak{m}_Q$ corresponding to $Q$. – Zhen Lin Sep 22 '12 at 15:51
As Zhen mentions in the comments, the local ring of $V(xy)\subseteq\Bbb C^2$ is the localization $\left(\dfrac{\Bbb C[x,y]}{(xy)}\right)_{(x,y)},$ since $(x,y)$ is the maximal ideal corresponding to the point $(0,0).$
An important property of localization is that it commutes with quotients. In this case, we have $\left(\dfrac{\Bbb C[x,y]}{(xy)}\right)_{(x,y)}=\dfrac{\Bbb C[x,y]_{(x,y)}}{(xy)}.$ Since we know that $\Bbb C[x,y]_{(x,y)}$ is the subring of $\Bbb C(x,y)$ consisting of elements $\dfrac{f(x,y)}{g(x,y)}$ satisfying $g(0,0)\neq 0,$ we can see that $\dfrac{\Bbb C[x,y]_{(x,y)}}{(xy)}$ consists of elements $\dfrac{f(x,y)}{g(x,y)}$ where $g(0,0)\neq 0,$ but also where $f(x,y),g(x,y)$ can have no mixed term monomials $x^\alpha y^\beta$ with $\alpha,\beta\neq 0$ with nonzero coefficient. | {"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": 0.937408447265625, "perplexity": 148.27499587711625}, "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-2014-35/segments/1408500834883.60/warc/CC-MAIN-20140820021354-00374-ip-10-180-136-8.ec2.internal.warc.gz"} |
https://www.gamedev.net/blogs/entry/1412140-update/ | • entries
707
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• views
434740
# Update
60 views
Making progress on my entry. Spent most of yesterday figuring out the changes between XNA beta and the new release.
Got my BitmapFont class converted from C++ to C#; works better and works right (found a nice little quirk in it.) Here's a screenshot:
(Just random test text.)
Shows vertical-center, center alignment, word-break, and color formatting. I changed the system a tiny bit from before. Now using ^0 resets the color to the color specified by the function call. Here's the code for the sample above:
TimeElapsed += (float)GameTime.ElapsedGameTime.Milliseconds / 1000.0f;if(TimeElapsed > 1){ TimeElapsed = 0; ++LineCount;}Graphics.GraphicsDevice.Clear(Color.Black);SpriteBatch.Begin(SpriteBlendMode.AlphaBlend);SpriteBatch.Draw(CursorTexture, new Rectangle((int)CursorPosition.X, (int)CursorPosition.Y, 32, 32), Color.White);SpriteBatch.End();Font.PreRender();Font.Print(String.Format("Mouse XY({0},{1})", CursorPosition.X, CursorPosition.Y), 0, CursorPosition + new Vector2(32.0f, 32.0f), FontFormatting.Left, (int)Color.Red.PackedValue);Font.PostRender();String[] Lines ={ "255,0,0Delta Squad Leader^0: Alpha Squad, come in.", "...", "...", "0,0,255???^0: I. ..at y.. ..als?", "255,0,0Delta Squad Leader^0: Message scrambled; repeat.", "0,0,255???^0: I said, is that you Beals?", "255,0,0Beals^0: About fucking time you assholes made it to high ground. What's your status?", "0,0,255Alpha Squad Leader^0: We're in the 255,255,0laboratory^0, making our way to the roof. We lost Seraph a couple floors down.", "255,0,0Beals^0: Damnit. Keep moving, we'll try to go back down when we regroup.",};if(LineCount > Lines.Length) LineCount = Lines.Length;String Output = "";for(int Index = 0; Index < LineCount; ++Index)Output += Lines[Index] + "\n";Mark2.PreRender();Mark2.Print(Output, 0, new Rectangle(0, 0, 800, 600), FontFormatting.WordBreak | FontFormatting.VCenter | FontFormatting.Center, (int)0xff808080);Mark2.PostRender();base.Draw(GameTime);
You can't see it from the screenshot, so here's the gist of things:
Every second a new line of text is added
Escape exits
The cursor is controlled by the mouse or the 360 controller
Pressing back on the 360 controller exits
...
That's about it. More stuff will be coming though.
I have to say I absolutely love writing font engines (and other associated stuff like GUIs.)
Anyway, more stuff coming tomorrow. Oh, and thanks for 44k views and 978 posts; you guys rock!
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https://www.gamedev.net/forums/topic/343335-probability/ | • 13
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# Probability
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I haven't studied probability in school yet, so bear with me in case I use bad terminology or a wrong method of thinking. The scenario: I'm designing a simplistic RPG combat system. The player is able to deal a certain amount of damage in numerical form, depending on his level. As his level increases, I want the probability of hitting high values to increase, and the probability of missing (hitting 0) to decrease. My attempt at the solution: Use a graph. The X-axis runs from 0 to 100 and the Y-axis runs from 0 to 1. In the game, a random number will be generated between 0 and 100. This number will be the input to a function f(x). The output is a number between 0 and 1, which will be used as a percentage of the player's max hit -- i.e., and output of 1 means the player hit his maximum, .5 means the player hit half the max, etc. Now, this f(x) function will be different depending on the player's ability. I have 3 graphs here - first is the graph of f(x) if the player's level is low, second is if his level is medium, and the last on is what f(x) should look like if the player's level is high: Note: p1 and p2 are the same points in all graphs. Negative numbers will be treated as 0. The question: What should the equation look like? I haven't studied higher level math yet (this year I'm only in precalc), so I don't really know what to do. My thinking is that this equation would have more than 1 input, as in, instead of f(x), it would be f(x,z) where z is the players ability. Is this possible/acceptable in math? What is the correct way of doing this? I'll take whatever help you can offer!
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Heres something quick I made up. It shouldn't be too hard to figure out how it works.
y = (x/100)^(2-1.5z)
Hope it helps.
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I guess a way you could do something like this is say the player can reach a max level of 100 or less, but greater than 0. For example, the player could have a level from 1 to 50, or 1 to 100. Then use this function:
probability = log(level)+c /(2+c), where c is a constant > 0.
Then you would generate a random number between 0.0 and 1.0 and if the generated number is less than or equal to the probability, then the player has hit his maximum.
An example.
Level = 1
c = 0.05
Log(1) + 0.05 / (2 + 0.05)
= 0 + 0.05 / 2.05
= 0.05 / 2.05
= 0.02439...
which means the player has about a 2.4 chance of dealing his maximum damage at level 1.
At level 50 it would be something like this:
Level = 50
c = 0.05
Log(50) + 0.05 / 2.05 = 0.8531...
And at level 100 the probability would be 100%
The value of c can be tweaked to change the curve a bit and allow you to control the probability at level 1.
How did I get this? Well there are, say 100 levels. Log(100) = 2. That is where we get the constant 2 from. If we had more than 100 levels, the constant 2 would have to be changed to the Log of the highest level. So if we were at level 100, the probability would be 2. That was too high. It is out of the range 0 to 1. So divide by 2. But the problem is that Log(1) = 0. So we add the constant in so we get a non-zero value. However, this meant that we would go out of range again, so we add the constant when we divide. This puts us right back into the range we wanted.
A more general version of this function would be:
Log(level) + c / ( Log(max_levels) + c )
Hope this solves your problem.
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Wouldn't a single graph sufice? More or less like so:
/\| ....| ..| .| .| ..|....+-------------->
An aproximation of a combination of all three graphs in one.
y = ( x-50/|x-50| - (1/(x-50)) ) + 0.5
I think this one up here might do the trick, i add 0.5 in the end, so that the function is centered in the Y axis, and use x-50 instead of x so that is is centered in the x axis, the function is also invalid for x=50, because a divide by zero happens, and x must be integer.
y = 1 - (1/x)
y = -1 - (1/x)
These were the original functions, in the first one i'de start with 1 and progressively take smaller and smaller parts of 1 as x increases to create a curve that rises very fast and then very slowly. In the second one the oposite, start with -1 and progressively increase smaller and smaller parts of 1 as x decreases. To put these two together i needed then to change the first one in both functions by x/|x|, so that i get 1 when x is positive and -1 when it is negative. The rest of the changes are the offsets, already described above.
If you want the funtion with more curvature just increase x(to 2x, 3x, x^2, whatever), if you want it with less, decrease x(to x/2, x/3, sqrt(x)).
[Edited by - xor on September 4, 2005 12:50:43 AM]
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Well, your first graph is quadratic, the second linear, and the third logarithmic.
So:
f1 will be of the form f(x) = ax^2 + bx + c
f2 will be of the form f(x) = mx + b
f3 will be of the form f(x) = log x
The next step is to specialize these forms for your input and output sets.
Starting off with x/100 creates a number proportional to x, and within the interval [0,1]. So we can set f2 = (1/100)x.
For f1 and f3, we need to do something to x/100 to change the shape of the graph, but without altering the functions domain.
Differentiating f2 yields f2' = 1/100.
For f1, we need this derivative to be relatively small for small x, and relatively large for large x. Multiplying f2' by x gives us a slope which increases with x.
Therefore, f1 = integral of x/100 = x^2/200. This function has a domain of 50, so we divide by fifty to retain the old domain yielding:
f1 = x^2/10000
If that curve steepens too quickly, just multiply f2' by x^2 rather than x (this yields f1 = x^3/1000000).
For f3 we want f2' to be large for small x, and small for lage x. This just happens to be a characteristic of the logarithm.
Suppose we multiply f2' by log(x). Well, x can't ever be greater than 100, and log(100) is 2. This means we need to modify the slope to be:
log(x)/2
Integrating yields f3 = log(x^2)/4.
This is going to generally yield fairly high probabilities.
EDIT: Sorry, I misread your post. I thought you were in calculus, but you're in precalculus. You may not understand what I'm talking about in this post then. [smile]
HTH,
nilkn
[Edited by - nilkn on September 4, 2005 12:07:45 AM]
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Quote:
Original post by mike25025Heres something quick I made up. It shouldn't be too hard to figure out how it works.y = (x/100)^(2-1.5z)Hope it helps.
I agree, this is probably very close to what the OP wants. What the OP has illustrated is a series of graphs with decreasing power. As was already mentioned, quadratic, linear, and logarithmic, although the last one could well be some power < 1.
Anyway, you're problem now is to take an equation like this an apply the boundary conditions. That is, making it line up with p1 and p2. Might I suggest starting with something like y = m * (x/100)^(2-1.5z) + b, doing a bit of algebraic substitutions involving p1 and p2, and seeing what m and b turn out to be. This should give you a pretty good result.
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You didn't explictly state it, but it looks like you want to base the probability on the difference in the levels between the attacker and defender. I think this function works really well:
P(x) = atan(a*x+b) / pi + 0.5 x = level_of_attacker - level_of_defender a affects how quickly the values approach 0 and 1 b shifts the graph right and left
When a = 0.1 and b = 0, the graph looks like this:
The nice thing about this function is that it is simple, configurable, and continuous. Also, the probabilities are never 0% or 100%. | {"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": 0.6340430378913879, "perplexity": 568.5355149253534}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257647153.50/warc/CC-MAIN-20180319214457-20180319234457-00779.warc.gz"} |
http://codeforces.com/problemset/problem/1250/H | H. Happy Birthday
time limit per test
2 seconds
memory limit per test
512 megabytes
input
standard input
output
standard output
You have a set of birthday cake candles. Each of such candles represents a digit between $0$ and $9$, inclusive.
Example of birthday cake candles.
Let's denote the candle representing the digit $d$ as $d$-candle.
Your set contains $c_0$ instances of $0$-candles, $c_1$ instances of $1$-candles and so on. So, the total number of candles is $c_0+c_1+\dots+c_9$.
These digits are needed to wish your cat a happy birthday. For each birthday, starting with the first, you want to compose the age of the cat using the digits from the set.
Since you light candles for a very short time, candles don't have time to burn out. For this reason you can reuse candles an arbitrary number of times (therefore your set of candles never changes).
For example, if you have one instance of each digit (i.e. $c_0=c_1=\dots=c_9=1$), you can compose any number from $1$ to $10$ using this set, but you cannot compose $11$.
You have to determine the first birthday, on which you cannot compose the age of the cat using the candles from your set. In other words, find the minimum number $y$ such that all numbers from $1$ to $y-1$ can be composed by digits from your set, but $y$ cannot be composed.
Input
The first line contains an integer $t$ ($1 \le t \le 10^4$) — the number of test cases in the input.
The only line of each test case contains ten integer numbers $c_0, c_1, \dots, c_9$ ($0 \le c_i \le 10^5$) — the number of $0$-candles, $1$-candles, $2$-candles and so on.
It is guaranteed that the sum of all $c_i$ in the input does not exceed $10^6$.
Output
For each test case, output one integer in single line — the minimum age which cannot be composed by candles from your set. Please note that the age can be quite large (it may exceed the standard 64-bit integer types in your programming language).
Example
Input
4
1 1 1 1 1 1 1 1 1 1
0 0 1 1 2 2 3 3 4 4
1 2 1 2 1 3 1 0 0 0
0 1 2 1 4 3 1 1 2 1
Output
11
1
7
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": 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": 0.434057354927063, "perplexity": 391.27712137323783}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585371611051.77/warc/CC-MAIN-20200405213008-20200406003508-00075.warc.gz"} |
http://www.kernel-machines.org/publications/SmoMurSchMul98/?searchterm=None | ##### Personal tools
You are here: Home Asymptotically Optimal Choice of $\varepsilon$-Loss for Support Vector Machines
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A. Smola, N. Murata, B. Sch\"olkopf, and K.-R. M\"uller (1998)
# Asymptotically Optimal Choice of $\varepsilon$-Loss for Support Vector Machines
In: Proceedings of ICANN'98, ed. by L. Niklasson and M. Bod\'en and T. Ziemke, pp. 105–110, Berlin, Springer Verlag. Perspectives in Neural Computing.
Under the assumption of asymptotically unbiased estimators it is shown that there exists a nontrivial choice of the insensitivity parameter in Vapnik's epsilon–insensitive loss function which scales linearly with the input noise of the training data. This finding is backed by experimental results. | {"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": 0.7989383935928345, "perplexity": 4516.683729953723}, "config": {"markdown_headings": true, "markdown_code": false, "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-2018-26/segments/1529267866926.96/warc/CC-MAIN-20180624083011-20180624103011-00494.warc.gz"} |
http://mathhelpforum.com/discrete-math/142145-possble-seating-plans.html | # Math Help - possble seating plans
1. ## possble seating plans
Seems simple one,but I have conflict on this with one of my friend.
There are 5 chairs in a row, and three people. In how many ways can
you place the people on the chairs? (each person must occupy exactly
one chair, so that two chairs will remain free).
So if by p(5,3), you mean $_3P_5=\frac{5!}{(5-3)!}$, your answer is correct. | {"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": 1, "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": 0.5560994744300842, "perplexity": 3268.2275133687567}, "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-2015-11/segments/1424936466999.23/warc/CC-MAIN-20150226074106-00214-ip-10-28-5-156.ec2.internal.warc.gz"} |
http://bootmath.com/proving-inequality-using-induction-an-bn-leq-nan-1a-b.html | # Proving Inequality using Induction $a^n-b^n \leq na^{n-1}(a-b)$
I was trying to prove this inequality using induction, but couldn’t do.
Question: Suppose $a$ and $b$ are real numbers with $0 < b < a$. Prove that if $n$ is a positive integer, then:
$$a^n-b^n \leq na^{n-1}(a-b)$$
#### Solutions Collecting From Web of "Proving Inequality using Induction $a^n-b^n \leq na^{n-1}(a-b)$"
You will want to use that $$a^n-b^n=(a-b)\sum_{k=0}^{n-1}a^{n-k-1}b^{k}$$
What can you say about the powers of $a,b$ given $0<b<a$?*
SPOILER
Since $0<b<a$, we have $0<b^k<a^k$
thus
\begin{align} a^n-b^n&=(a-b)\sum_{k=0}^{n-1}a^{n-k-1}b^{k}\\&<(a-b)\sum_{k=0}^{n-1}a^{n-k-1}a^{k}\\&=(a-b)\sum_{k=0}^{n-1}a^{n-1}\\&=(a-b)na^{n-1}\end{align}
Here is another somewhat related inequality:
$$a^n – b^n > n(a-b)(ab)^{(n-1)/2}$$ where $a > b > 0$ and $n \geq 1$. Here is a simple proof:
$$a^n-b^n=(a-b)\sum_{k=0}^{n-1}a^{n-k-1}b^{k}$$ Now apply AM-GM inequality on summation terms:
\begin{align}
\sum_{k=0}^{n-1}a^{n-k-1}b^{k} &< n \sqrt[n]{\prod_{k=0}^{n-1}{a^{n-k-1}b^{k}}} \\
&= n \sqrt[n]{a^{\sum_{k=0}^{n-1}{(n-k-1)}} \, b^{\sum_{k=0}^{n-1}{k}}} \\
&= n \sqrt[n]{a^{n(n-1)/2} \, b^{n(n-1)/2}} \\
&= n (ab)^{(n-1)/2}
\end{align}
You may use the mean value theorem to show this:
Define $f(x) = x^n$ on $[b, a]$, clearly, $f(x)$ is differentiable in $(b, a)$ and continuous on $[b, a]$. By MVT, there exists $\xi \in (b, a)$ such that
$$a^n – b^n = f(a) – f(b) = f'(\xi)(a – b) = n\xi^{n – 1}(a – b) \leq na^{n – 1}(a – b)$$
as $\xi < a$. | {"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": 1, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9870468378067017, "perplexity": 398.4351356386486}, "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/1531676591497.58/warc/CC-MAIN-20180720041611-20180720061611-00622.warc.gz"} |
http://kitcreator.rkeene.org/fossil/fdiff?v1=77ec27d4ef9f33ab&v2=442f0e77372507d5 | Diff
## To Artifact [442f0e7737]:
```36 37 38 39 40 41 42 43 44 45 46 47 48 49 ``` ```SAVE_LIBS="\${LIBS}" LIBS="\${ARCHS} \${LIBS}" dnl Determine if we have "Tcl_SetStartupScript" (8.6.x) or "TclSetStartupScriptPath" (8.4.x) AC_CHECK_FUNCS(Tcl_SetStartupScript TclSetStartupScriptPath) dnl Check for the ability to get the current system encoding AC_CHECK_FUNCS(Tcl_GetEncodingNameFromEnvironment Tcl_SetSystemEncoding) LIBS="\${SAVE_LIBS}" dnl Find zlib AC_ARG_WITH(zlib, AC_HELP_STRING([--with-zlib], [directory containing zlib]), [ CPPFLAGS="\${CPPFLAGS} -I\${with_zlib}/include -I\${with_zlib}" CFLAGS="\${CFLAGS} -I\${with_zlib}/include -I\${with_zlib}" LDFLAGS="\${LDFLAGS} -L\${with_zlib}/lib -L\${with_zlib}" ]) ``` ``` > > > ``` ```36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 ``` ```SAVE_LIBS="\${LIBS}" LIBS="\${ARCHS} \${LIBS}" dnl Determine if we have "Tcl_SetStartupScript" (8.6.x) or "TclSetStartupScriptPath" (8.4.x) AC_CHECK_FUNCS(Tcl_SetStartupScript TclSetStartupScriptPath) dnl Check for the ability to get the current system encoding AC_CHECK_FUNCS(Tcl_GetEncodingNameFromEnvironment Tcl_SetSystemEncoding) LIBS="\${SAVE_LIBS}" dnl Check for optional system calls AC_CHECK_FUNCS(readlink) dnl Find zlib AC_ARG_WITH(zlib, AC_HELP_STRING([--with-zlib], [directory containing zlib]), [ CPPFLAGS="\${CPPFLAGS} -I\${with_zlib}/include -I\${with_zlib}" CFLAGS="\${CFLAGS} -I\${with_zlib}/include -I\${with_zlib}" LDFLAGS="\${LDFLAGS} -L\${with_zlib}/lib -L\${with_zlib}" ]) ``` | {"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": 0.9860736727714539, "perplexity": 11331.610005260985}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "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-2020-34/segments/1596439739370.8/warc/CC-MAIN-20200814190500-20200814220500-00026.warc.gz"} |
http://scoskey.org/1718s-311 | Math 311, Spring 2018 (site)
Catalog description: Euclidean, non-Euclidean, and projective geometries from an axiomatic point of view. | {"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": 0.8385328650474548, "perplexity": 3173.227399414414}, "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-2018-30/segments/1531676591575.49/warc/CC-MAIN-20180720080634-20180720100634-00333.warc.gz"} |
https://www.physicsforums.com/threads/contradiction-in-thermodynamics-problem.799360/ | Tags:
1. Feb 22, 2015
### Amin2014
Consider a gas as your system, confined in the usual frictionless piston-cylinder. The piston is massless, external pressure is constant, Pext. Let the system be at initial state T1 and P1 = Pext. We want to compare the following two processes: in the first process, we reversibly heat the gas against constant external pressure to final volume V2. In the second process, we heat the gas irreversibly from the same initial conditions against the same constant pressure to reach the same final volume V2, and then we wait for the gas to reach internal equilibrium, so that P2= Pext and both the initial and final states of the two process are identical. Assuming the gas has constant Cp over the temperature range, we wish to compare qrev and qirrev
for the two processes, and also ∆S for the two processes.
Now here's the contradiction: ∆S should be equal for the two processes, since the initial and final states are the same. So let's calculate ∆S for the reversible process. Since it is reversible, we have ∆S = ∫dqrev/T, where dqrev = CpdT. So ∆S = Cp Ln T2/T1. This is also ∆S for the irreversible process.
Also qrev must equal qirrev since both are constant pressure processes, with ∆H, ∆U, W and q all being equal for both processes, right?
But what if we consider the inequality dS>dqirrev/T? If we use dqirrev=dqrev= CpdT, then we have ∆S>Cp Ln T2/T1, which contradicts our previous finding. Where have I gone wrong?
Last edited: Feb 22, 2015
2. Feb 22, 2015
### Bystander
How might you go about heating irreversibly from T1 to T2?
3. Feb 23, 2015
### Staff: Mentor
What a great question!!!!
It is not widely discussed, but the Clausius inequality is based on use of the temperature at the location where the heat transfer dq is occurring (i.e., at the interface between the system and the surroundings). During the irreversible heating, the temperature at this interface is higher than the bulk average temperature of the gas, so that, even though the same amount of heat is transferred, the integral of dq/TI is less for the irreversible case than for the reversible case (where TI represents the temperature at the interface).
Chet
4. Feb 23, 2015
### Amin2014
The entire setup is physically possible. We could for instance- without negatively affecting the rest of the problem- have a substance, say a monatomic gas, which has nearly constant Cp, especially if we keep the temperature range from being too big. It is perfectly possible to start from the same initial conditions, we could hold the external pressures constant in both cases, the piston doesn't really have to be massless if the set up is vertical (we'd just add the mass of the piston to the external pressure to calculate the work directly on the gas which we take as our system), we could even assume the irreversible heating is done with say a Bunsen-burner fume and ask to calculate the change in entropy of the surroundings as a bonus brain teaser (now how would you do that?).
Also we could reach the same final states because in either case when the piston is at rest, the ultimate equilibrium pressure will be P2= Pext.
So all we have to do is reach the same final volumes for the final states to be identical, and that too is possible in this particular problem; we irreversibly heat the system and find that sweet spot with trial and error ;)
The specific details of the irreversible heating, are not given in the problem though, for instance the finite temperature difference, and you would be correct to suspect that as a key to resolving the contradiction (I was actually able to solve the problem a few hours after posting the question, but plz do provide your own resolution so we can all learn from it ;) )
Last edited: Feb 23, 2015
5. Feb 23, 2015
### Staff: Mentor
Did you not see my post #3?
Chet
6. Feb 23, 2015
### Amin2014
Yes I did Chet, it's just that your answer was deep and got me thinking on a LOOOOOT of things lol. I understand what you said and think that you are correct, however your answer has opened doors to new questions for me, will get back to you.
7. Feb 23, 2015
### Amin2014
Actually, having thought on Chet's answer, It seems to me that the only way to establish a final state of equilibrium during irreversible heating would be to emerge the system in a heat reservoir (constant temperature bath) with the desired final temperature. This way we ensure that both the final pressure and temperature of our system in the irreversible process eventually equal that of the reversible heating.
If however, we choose to do the heating with a Bunsen-burner fume, all the while the temperature of the surrounding atmosphere remaining equal to the initial temperature (say 298 K), then we can't hope to establish a final state of equilibrium in the irreversible process (see why?). While calculating the change in entropy of surroundings in this condition is intriguing, I cannot think of any simple way to do so. Would it be necessary to integrate over the surface of the surroundings in contact with system, or is there a way to simplify the problem? Any thoughts Chet?
8. Feb 23, 2015
### Staff: Mentor
Excellent. While you are thinking about it, I'm going to give you something else to look over. This is a write up I did which at one time was my PF blog (when PF still have blogs). It is a brief description of the First and Second laws, presented in a slightly different way than what you're used to.
I'm starting this blog on thermodynamics because I have some ways of presenting the material that I think can help people learn the subject more easily.
FIRST LAW OF THERMODYNAMICS
Suppose that we have a closed system that at initial time ti is in an initial equilibrium state, with internal energy Ui, and at a later time tf, it is in a new equilibrium state with internal energy Uf. The transition from the initial equilibrium state to the final equilibrium state is brought about by imposing a time-dependent heat flow across the interface between the system and the surroundings, and a time-dependent rate of doing work at the interface between the system and the surroundings. Let $\dot{q}(t)$ represent the rate of heat addition across the interface between the system and the surroundings at time t, and let $\dot{w}(t)$ represent the rate at which the system does work on the surroundings at the interface at time t. According to the first law (basically conservation of energy),
$$ΔU=U_f-U_i=\int_{t_i}^{t_f}{(\dot{q}(t)-\dot{w}(t))dt}=Q-W$$
where Q is the total amount of heat added and W is the total amount of work done by the system on the surroundings at the interface.
The time variation of $\dot{q}(t)$ and $\dot{w}(t)$ between the initial and final states uniquely characterizes the so-called process path. There are an infinite number of possible process paths that can take the system from the initial to the final equilibrium state. The only constraint is that Q-W must be the same for all of them.
If a process path is irreversible, then the temperature and pressure within the system are typically inhomogeneous (i.e., non-uniform, varying with spatial position), and one cannot define a unique pressure or temperature for the system (except at the initial and the final equilibrium state). However, the pressure and temperature at the interface can be measured and controlled using the surroundings to impose the temperature and pressure boundary conditions that we desire. Thus, TI(t) and PI(t) can be used to impose the process path that we desire. Alternately, and even more fundamentally, we can directly control, by well established methods, the rate of heat flow and the rate of doing work at the interface $\dot{q}(t)$ and $\dot{w}(t)$).
Both for reversible and irreversible process paths, the rate at which the system does work on the surroundings is given by:
$$\dot{w}(t)=P_I(t)\dot{V}(t)$$
where $\dot{V}(t)$ is the rate of change of system volume at time t. However, if the process path is reversible, the pressure P within the system is uniform, and
$P_I(t)=P(t)$ (reversible process path)
Therefore, $\dot{w}(t)=P(t)\dot{V}(t)$ (reversible process path)
Another feature of reversible process paths is that they are carried out very slowly, so that $\dot{q}(t)$ and $\dot{w}(t)$ are both very close to zero over then entire process path. However, the amount of time between the initial equilibrium state and the final equilibrium state (tf-ti) becomes exceedingly large. In this way, Q-W remains constant and finite.
SECOND LAW OF THERMODYNAMICS
In the previous section, we focused on the infinite number of process paths that are capable of taking a closed thermodynamic system from an initial equilibrium state to a final equilibrium state. Each of these process paths is uniquely determined by specifying the heat transfer rate $\dot{q}(t)$ and the rate of doing work $\dot{w}(t)$ as functions of time at the interface between the system and the surroundings. We noted that the cumulative amount of heat transfer and the cumulative amount of work done over an entire process path are given by the two integrals:
$$Q=\int_{t_i}^{t_f}{\dot{q}(t)dt}$$
$$W=\int_{t_i}^{t_f}{\dot{w}(t)dt}$$
In the present section, we will be introducing a third integral of this type (involving the heat transfer rate $\dot{q}(t)$) to provide a basis for establishing a precise mathematical statement of the Second Law of Thermodynamics.
The discovery of the Second Law came about in the 19th century, and involved contributions by many brilliant scientists. There have been many statements of the Second Law over the years, couched in complicated language and multi-word sentences, typically involving heat reservoirs, Carnot engines, and the like. These statements have been a source of unending confusion for students of thermodynamics for over a hundred years. What has been sorely needed is a precise mathematical definition of the Second Law that avoids all the complicated rhetoric. The sad part about all this is that such a precise definition has existed all along. The definition was formulated by Clausius back in the 1800's.
Clausius wondered what would happen if he evaluated the following integral over each of the possible process paths between the initial and final equilibrium states of a closed system:
$$I=\int_{t_i}^{t_f}{\frac{\dot{q}(t)}{T_I(t)}dt}$$
where TI(t) is the temperature at the interface with the surroundings at time t. He carried out extensive calculations on many systems undergoing a variety of both reversible and irreversible paths and discovered something astonishing. He found that, for any closed system, the values calculated for the integral over all the possible reversible and irreversible paths (between the initial and final equilibrium states) was not arbitrary; instead, there was a unique upper bound (maximum) to the value of the integral. Clausius also found that this result was consistent with all the "word definitions" of the Second Law.
Clearly, if there was an upper bound for this integral, this upper bound had to depend only on the two equilibrium states, and not on the path between them. It must therefore be regarded as a point function of state. Clausius named this point function Entropy.
But how could the value of this point function be determined without evaluating the integral over every possible process path between the initial and final equilibrium states to find the maximum? Clausius made another discovery. He determined that, out of the infinite number of possible process paths, there existed a well-defined subset, each member of which gave the same maximum value for the integral. This subset consisted of what we call today the reversible process paths. So, to determine the change in entropy between two equilibrium states, one must first conceive of a reversible path between the states and then evaluate the integral. Any other process path will give a value for the integral lower than the entropy change.
So, mathematically, we can now state the Second Law as follows:
$$I=\int_{t_i}^{t_f}{\frac{\dot{q}(t)}{T_I(t)}dt} \le ΔS = \int_{t_i}^{t_f} {\frac{\dot{q}_{rev}(t)}{T(t)}dt}$$
where $\dot{q}_{rev}(t)$ is the heat transfer rate for any of the reversible paths between the initial and final equilibrium states, and T(t) is the system temperature at time t (which, for a reversible path, is equal to the temperature at the interface with the surroundings). This constitutes a precise mathematical statement of the Second Law of Thermodynamics.
Chet
9. Feb 23, 2015
### Staff: Mentor
The way to do the irreversible path is to guarantee that the total amount of heat transferred is the same. This will guarantee that the final temperature and volume will be the same as for the reversible path. How this is accomplished in practice is a separate issue.
As far as the surroundings are concerned, we don't need to concern ourselves with that if our focus is the system, and we are testing the Clausius inequality with respect to the system. That's what's nice about doing it all with the Clausius inequality. You don't need to address all the possible things that could be happening in the surroundings.
Chet
10. Feb 23, 2015
### Bystander
Period, end of sentence, problem solved.
11. Feb 23, 2015
### Staff: Mentor
12. Feb 23, 2015
### Amin2014
OK I see what you are doing there, trying to get the students to calculate and apply the forces and works and everything correctly. you may want to emphasize a few points though:
1- absence of macroscopic kinetic energy and potential energies, or else it is E (total energy), not U (internal energy) that should be stated in the first law.
2- You've omitted the definition of quasi-static processes and replaced it with reversible processes.
3- Choosing the boundary, defining the boundary and keeping in mind what the boundary of the system is throughout. This has two implications: first, it means that we need to add ALL the works done throughout this boundary. And since work is defined in terms of forces, we must first account for all the working forces in our diagram. Same goes for calculating the remaining microscopic work (heat). Also, this implies that if we choose a different system as our focus, the terms for work and heat could change. So for instance a force that is external to the piston may not necessarily be external to our system, depending on whether our system boundary comes in direct contact with the external surface of the piston or not (which it usually doesn't, usually it's the internal surface of the piston that kisses the system).
4- The definition of reversible processes has nothing to do with the first law, and it doesn't even make sense to define such a process while analyzing the first law. The motivation for definition of reversible processes arises when one tries to prove (based on the assumption of validity of the second law), that ∫dqrev/T = 0 in any closed path. Here, a reversible process is defined as one where you can restore BOTH the system and surroundings to their original states. This means if you replace w with -w, and q with minus q (the only way to completely restore the surroundings), you would have also restored the system. SO in essence, a reversible process is one where you can reverse or "flip" everything(i.e. the inputs, outputs and the process within the system) in the diagram. We see this definition or property of reversible processes used explicitly in proving things like maximum efficiency of carnot cycles, which ultimately leads to the definition of entropy.
So this is why they define the reversible process, and they do so in the second law, not the first.
Defining a quasi-static process, one where the only necessary condition is the process being infinitely slow (whether or not we can flip everything in the diagram), allows us to use dW= -pdV, where p is the bulk pressure of system, instead of dw= -pextdV, since the two pressures are equal in such processes. For instance, we could use dW= -pdV even if the process is not reversible, provided it is quasi-static (infinitely slow). One such process could be an infinitely slow process in the presence of friction (can't flip the diagrams!).
Also you may want to distinguish between being mechanically, thermally and chemically reversible. All of this requires lots of careful teaching (or self learning).
Last edited: Feb 23, 2015
13. Feb 23, 2015
### Amin2014
As you know Chet, all reversible processes are infinitely slow, but not all infinitely slow processes are reversible, so you might want to emphasize that.
Except I have one question, are really all reversible processes infinitely slow? Is there no reversible process that can be done over finite time? What about converting Ice to water at 1 atm, 0 C?
14. Feb 23, 2015
### Amin2014
Yes thnx, I got that from your first post by writing dSt= dS + dSsurr >0 and working backwards (forwards?).
15. Feb 23, 2015
### Staff: Mentor
Hi amin2014. Thanks for your constructive criticism and suggestions. You need to understand my motivation for writing this. My target audience was new thermo students who are struggling to learn the basic concepts, but who have developed many misconceptions because of the poor way that thermo is presented in the typical textbooks that are used. Constantly, on Physics Forums, we encounter these same misconceptions. So I wanted to provide the students with supplementary material that was presented in a little different way, and I wanted to keep it very concise so that they would not lose interest. Some of the misconceptions I hoped to address were:
1. Isn't the work PdV? Why do we have to use PextdV to get the work when the process is irreversible?
2. Isn't the change in entropy always equal to the integral of dq/T, irrespective of whether the path is reversible or irreversible?
3. The entropy is not a material property of the system. It depends on path, and can only be determined for a specific process path.
4. The temperature T in the Clausius inequality is the temperature of the system.
I'm going to try to address some of the points that you raised, and then I have a proposal for you.
Yes. This is, of course, correct, but I was trying to keep the development as simple as possible (and as close to what I deemed they had previoiusly learned) so that I could emphasize the points that I thought were most important.
Yes. This is very true. We need to carefully specify the system that we are focusing upon. Also, we need to include all the heats that enter, sometimes through different parts of the interface with the surroundings. This also goes for applying the Clausius Inequality.
This goes back to item 1 on my list of misconceptions. Maybe I should have used "quasistatic" rather than "reversible" in what I said.
You're preaching to the choir. But, another reason for introducing reversible paths is to provide a basis for determining the change in entropy.
Yes. As I said, maybe I should have said quasistatic instead of reversible.
Yes. Up to the point I had shown, I was just trying to keep it as simple as possible.
I have been toying with the idea of doing additional writing, but just haven't gotten around to it. That would certainly include approaches to achieving mechanical, thermal, and chemical reversibility.
Here's my proposal. How about we collaborate on improving what I have written and maybe even adding additional sections? We could do this in private conversations. I would be glad to participate, provided I had final literary say. Any interest?
Chet
16. Feb 23, 2015
### Staff: Mentor
This is a situation that is expected to be much closer to being reversible than others. However, even here, you need to have some temperature gradients in the ice water to provide the heat transfer to the ice, and the amount of irreversibility will be greater if you try to carry out the change at a very high heat transfer rate. Irreverisiblity will always be present if you have significant rates of deformation (viscous heating), rates of heat transfer (heat conduction), rates of mass transfer (mixing/diffusion), or rates of chemical reaction.
Chet
17. Feb 24, 2015
### Amin2014
Intriguing suggestion Chet, let me know the details of how you are writing this, what you are writing about.
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https://net.nthu.edu.tw/netsys/en:mailing:announcement:20190821_01 | # Application for student dormitory network in 108 Semester from 10:00am on Tuesday 27th August, 2019.
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Computer and Communication Center | {"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": 0.8923819661140442, "perplexity": 12873.201244136204}, "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-2020-45/segments/1603107894175.55/warc/CC-MAIN-20201027111346-20201027141346-00315.warc.gz"} |
https://askbot.fedoraproject.org/pt-br/question/116494/sudo-dont-ask-password-solved/?answer=116651 | Pergunte aqui
All operations using sudo are not asking for a password, how to solve this? I do not want an automatic password. I use Fedora 27 KDE
editar alterar tag fechar mesclar Excluir
## 7 Respostas
I assume that your problem is that sometimes sudo asks for a password and sometimes not and you can't figure out why this happens.
From www.sudo.ws:
• Sudo uses timestamp files to implement a "ticketing" system. When a user invokes sudo and enters their password, they are granted a ticket for 5 minutes (this timeout is configurable at compile-time). Each subsequent sudo command updates the ticket for another 5 minutes. This avoids the problem of leaving a root shell where others can physically get to your keyboard. There is also an easy way for a user to remove their ticket file, useful for placing in a .logout file.
This behaviour can be changed in the sudoers file by changing the value of the parameter timestamp_timeout
First edit the /etc/sudoers file using the command visudo
In the section where the Defaults specifications are located, insert the following line
Defaults timestamp_timeout = 0
Now the timeout for the user tickets is zero which means that sudo will always ask the password.
mais
I found the solution
System Settings
All configurations
Account details
Users Manager
I entered the password, because I believe it was blank and since my user is an administrator, he did not ask for a password
Now it's fixed!
mais
thanks for the answer, but the line is already commented, as below:
## Same thing without a password
# %wheel ALL=(ALL) NOPASSWD: ALL
More ideas or suggestions?
mais
## Comentários
It needs to look exactly like this:
#%wheel ALL=(ALL) NOPASSWD: ALL
The line that you quote isn't a comment and that's why you're not being asked for a password.
( 2018-01-19 17:12:39 -0500 )editar
? I'm not sure I follow you here, sideburns; the space following the # character is inconsequential; the line he quotes is, indeed, commented and will not take effect in his /etc/sudoers file.
( 2018-01-20 06:19:37 -0500 )editar
Is correct?
## Allow root to run any commands anywhere
root ALL=(ALL) ALL
## Allows members of the 'sys' group to run networking, software,
## service management apps and more.
# %sys ALL = NETWORKING, SOFTWARE, SERVICES, STORAGE, DELEGATING, PROCESSES, LOCATE, DRIVERS
## Allows people in group wheel to run all commands
%wheel ALL=(ALL) ALL
## Same thing without a password
# %wheel ALL=(ALL) NOPASSWD: ALL
( 2018-01-20 07:55:07 -0500 )editar
Before the latest edit, that line didn't have a # at the front, and wasn't a comment. The edit changed everything.
( 2018-01-20 13:26:22 -0500 )editar
please use the formatting preformatted text (symbol: 101010) when pasting text here. the# is otherwise interpreted as character to format text and it ends up looking the way it did.
( 2018-01-20 22:10:57 -0500 )editar
It is important to always edit /etc/sudoers with the command visudo. That's a vim-based, sudoers-specific editing interface which performs sanity checks before it lets you commit changes to /etc/sudoers. This is particularly important when you're administering remote systems or any other system where you cannot directly log in as root, but must use sudo privileges; if you break /etc/sudoers, you'll lock yourself out of those essential privileges. So always use visudo.
That said, you likely have some sort of non-commented configuration directive in your /etc/sudoers file with "NOPASSWD" in it.
To figure out what your resulting set of privileges are for sudo, execute sudo -l as yourself; that should give you additional information about what commands you are able to run and which default entries apply to your user account.
Feel free to post your /etc/sudoers file, changing any group or user names (in a consistent way, of course) which you don't want to divulge, and we can likely isolate the issue for you if you cannot find it.
mais
I did this... but it did not work
mais
# %wheel ALL=(ALL) NOPASSWD: ALL
I left one, two # and it did not work ...
I erased both lines and it did not work (then put them back)
mais
Welcome to ask.fedora. That's an odd issue you have, and a potential security hole. My guess is that you have something wrong in its configuration file, /etc/sudoers. Edit it with whatever text editor you prefer (You'll need to use sudo to edit it.) and look for a line that looks like this:
%wheel ALL=(ALL) NOPASSWD: ALL
Edit the line by adding # to the beginning, making it into a comment, then save and exit. I don't know if you'll have to reboot, but if you're not getting asked for a password after the edit, do so. This should clear the issue up, but do come back and let us know in either case.
mais | {"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": 0.3524486720561981, "perplexity": 4325.015243527915}, "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-2021-25/segments/1623487643354.47/warc/CC-MAIN-20210618230338-20210619020338-00144.warc.gz"} |
https://proxieslive.com/tag/otimes_mathbbk/ | ## Why is $\mathbb{K}[X] \otimes_{\mathbb{K}} \mathbb{K}[Y] \longrightarrow \mathbb{K}[X \times Y]$ surjective?
I am studying products in the category of affine varieties and I don’t know how to prove that the map
$$\mathbb{K}[X] \otimes_{\mathbb{K}} \mathbb{K}[Y] \longrightarrow \mathbb{K}[X \times Y],$$
where $$X$$ is a affine variety and $$\mathbb{K}[X]$$ is the ring of regular function on $$X$$, is surjective.
I know that if $$W \subset \mathbb{A}^n$$ is a closed subset then $$\mathbb{K}[W] \simeq \mathbb{K}[z_1, \dots,z_n]/I(W)$$ but I can’t link the two results.
Have you any hints? | {"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": 6, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7882778644561768, "perplexity": 77.47936383351147}, "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/1634323587908.20/warc/CC-MAIN-20211026134839-20211026164839-00027.warc.gz"} |
http://stke.sciencemag.org/content/2004/262/tw437 | Editors' ChoiceImmunology
# Receptors on the Move
+ See all authors and affiliations
Science's STKE 07 Dec 2004:
Vol. 2004, Issue 262, pp. tw437
DOI: 10.1126/stke.2622004tw437
When T cells, B cells, and natural killer (NK) cells of the immune system interact with target cells, signaling molecules are accumulated in the plasma membrane at structures known as the immunological synapse. Evidence is accumulating that proteins, as well as signals, are transferred between the interacting cells at such contacts. NK cells receive inhibitory signals from cells that express self major histocompatibility complex (MHC) molecules on their surface. Earlier evidence had shown that NK cells can actually acquire MHC class I proteins during interactions with target cells. Now Vanherberghen et al. show that the exchange goes both ways and that NK receptors are transferred to cells that express MHC class I ligands. The authors monitored transfer of biotinylated killer Ig-like receptor (KIR) KIR2DL1 by immunoblotting or green fluorescent protein-tagged receptor by fluorescence-activated cell sorting or laser-scanning confocal microscopy and observed transfer of KIRs. The NK cell receptor Ly49A was only transferred to target cells that expressed the cognate MHC class I ligand. It is not known what function the transferred receptor might serve, but the authors make an appealing suggestion: The NK receptor might mark a target cell that has already been scanned by a NK cell, which might allow more efficient surveillance by NK cells if they could use such a marker to avoid rescanning of the same cell.
B. Vanherberghen, K. Andersson, L. M. Carlin, E. N. M. Nolte-`t Hoen, G. S. Williams, P. Höglund, D. M. Davis, Human and murine inhibitory natural killer cell receptors transfer from natural killer cells to target cells. Proc. Natl. Acad. Sci. U.S.A. 101, 16873-16878 (2004). [Abstract] [Full Text] | {"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": 0.8703998327255249, "perplexity": 10928.586920532658}, "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/1498128323711.85/warc/CC-MAIN-20170628153051-20170628173051-00357.warc.gz"} |
http://mathoverflow.net/questions/87561/relationship-between-hyperbolicity-in-group-theory-and-hyperbolicity-in-geometry?sort=votes | # Relationship between hyperbolicity in group theory and hyperbolicity in geometry
Could somebody teach me about the relationship, if any, between hyperbolicity in groups (in Gromov sense) and hyperbolicity in 3-dimensional orbifolds? To be more specific, let Q be a 3-dimensional orbifold. If the orbifold fundamental group of Q is a hyperbolic group (in Gromov sense), then can we say that Q is a hyperbolic orbifold?
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Finite groups are Gromov hyperbolic, so $3$-manifolds like the $3$-sphere and lens spaces have hyperbolic fundamental groups but are not actually hyperbolic. If you want examples with infinite fundamental groups, take the connect sum of two lens spaces. – Andy Putman Feb 5 '12 at 6:20
If you want someone to teach you about the relationship, read Gromov's foundational paper. – Igor Rivin Feb 5 '12 at 19:56
To add to Andy's answer, you need to assume that the orbifold is irreducible and "good", so that there are no essential suborbifolds of Euler characteristic $>0$. – Ian Agol Feb 5 '12 at 20:41
The orbifold theorem was proved before geometrization, but a unified proof is now available: front.math.ucdavis.edu/1101.3733 – Ian Agol Feb 6 '12 at 5:49
Agol - I was playing it safe and allowing $Q$ to have empty orbifold locus. – Sam Nead Feb 6 '12 at 10:20
[See Peter Scott's Bulletin article for more information.] Typically, we say an orbifold $Q$ is hyperbolic if it comes to us as a quotient of hyperbolic space $H^n$ by the action of a discrete group $G$ of isometries. If the action $G$ is cocompact then $G$ will be a Gromov hyperbolic group. This is the "easy direction".
On the other hand, if $Q$ is an orbifold with enough topological hypotheses (for example, dimension three, irreducible, "good" as Agol says, perhaps more...) then, if the orbifold fundamental group of $Q$ is Gromov hyperbolic it follows from the geometrization theorem (Perelman and so on) that $Q$ is orbifold homeomorphic to a quotient as in the first paragraph.
So, roughly, the two notions are equivalent. However one direction is easy -- it follows from basic definitions in the field of coarse geometry -- and the other direction is one of the most famous recent results in mathematics.
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Many many thanks, Sam!!! – scarlet Feb 6 '12 at 1:08 | {"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": 0.9358060956001282, "perplexity": 560.6864700911269}, "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-2016-18/segments/1461861812410.28/warc/CC-MAIN-20160428164332-00136-ip-10-239-7-51.ec2.internal.warc.gz"} |
https://cole-trapnell-lab.github.io/monocle3/papers/ | ### The dynamics and regulators of cell fate decisions are revealed by pseudotemporal ordering of single cells
Cole Trapnell*, Davide Cacchiarelli*, Jonna Grimsby, Prapti Pokharel, Shuqiang Li, Michael Morse, Niall J. Lennon, Kenneth J. Livak, Tarjei S. Mikkelsen, John L. Rinn.
Nature Biotechnology 2014
Defining the transcriptional dynamics of a temporal process such as cell differentiation is challenging owing to the high variability in gene expression between individual cells. Time-series gene expression analyses of bulk cells have difficulty distinguishing early and late phases of a transcriptional cascade or identifying rare subpopulations of cells, and single-cell proteomic methods rely on a priori knowledge of key distinguishing markers. Here we describe Monocle, an unsupervised algorithm that increases the temporal resolution of transcriptome dynamics using single-cell RNA-Seq data collected at multiple time points. Applied to the differentiation of primary human myoblasts, Monocle revealed switch-like changes in expression of key regulatory factors, sequential waves of gene regulation, and expression of regulators that were not known to act in differentiation. We validated some of these predicted regulators in a loss-of function screen. Monocle can in principle be used to recover single-cell gene expression kinetics from a wide array of cellular processes, including differentiation, proliferation and oncogenic transformation
This is the original Monocle paper, which introduced the concept of pseudotime ordering for single-cell analysis
### Single-cell mRNA quantification and differential analysis with Census
Xiaojie Qiu, Andrew Hill, Jonathan Packer, Dejun Lin, Yi-An Ma, Cole Trapnell
Nature Methods 2017
Single-cell gene expression studies promise to reveal rare cell types and cryptic states, but the high variability of single-cell RNA-seq measurements frustrates efforts to assay transcriptional differences between cells. We introduce the Census algorithm to convert relative RNA-seq expression levels into relative transcript counts without the need for experimental spike-in controls. Analyzing changes in relative transcript counts led to dramatic improvements in accuracy compared to normalized read counts and enabled new statistical tests for identifying developmentally regulated genes. Census counts can be analyzed with widely used regression techniques to reveal changes in cell-fate-dependent gene expression, splicing patterns and allelic imbalances. We reanalyzed single-cell data from several developmental and disease studies, and demonstrate that Census enabled robust analysis at multiple layers of gene regulation. Census is freely available through our updated single-cell analysis toolkit, Monocle 2.
This paper describes BEAM (used in branch analysis) and Census (the core of relative2abs)
### Reversed graph embedding resolves complex single-cell trajectories
Xiaojie Qiu, Qi Mao, Ying Tang, Li Wang, Raghav Chawla, Hannah Pliner, Cole Trapnell
Nature Methods 2017
Single-cell trajectories can unveil how gene regulation governs cell fate decisions. However, learning the structure of complex trajectories with multiple branches remains a challenging computational problem. We present Monocle 2, an algorithm that uses reversed graph embedding to describe multiple fate decisions in a fully unsupervised manner. We applied Monocle 2 to two studies of blood development and found that mutations in the genes encoding key lineage transcription factors divert cells to alternative fates.
This paper describes Monocle 2 and the use of Reversed Graph Embedding for single-cell analysis.
### The single-cell transcriptional landscape of mammalian organogenesis
Junyue Cao, Malte Spielmann, Xiaojie Qiu, Xingfan Huang, Daniel M. Ibrahim, Andrew J. Hill, Fan Zhang, Stefan Mundlos, Lena Christiansen, Frank J. Steemers, Cole Trapnell, and Jay Shendure
Nature 2019
Mammalian organogenesis is a remarkable process. Within a short timeframe, the cells of the three germ layers transform into an embryo that includes most of the major internal and external organs. Here we investigate the transcriptional dynamics of mouse organogenesis at single-cell resolution. Using single-cell combinatorial indexing, we profiled the transcriptomes of around 2 million cells derived from 61 embryos staged between 9.5 and 13.5 days of gestation, in a single experiment. The resulting ‘mouse organogenesis cell atlas’ (MOCA) provides a global view of developmental processes during this critical window. We use Monocle 3 to identify hundreds of cell types and 56 trajectories, many of which are detected only because of the depth of cellular coverage, and collectively define thousands of corresponding marker genes. We explore the dynamics of gene expression within cell types and trajectories over time, including focused analyses of the apical ectodermal ridge, limb mesenchyme and skeletal muscle. | {"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": 0.5782235860824585, "perplexity": 9441.082957771827}, "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/1679296943698.79/warc/CC-MAIN-20230321131205-20230321161205-00003.warc.gz"} |
https://www.physicsforums.com/threads/another-circular-motion-question.70169/ | # Another Circular motion question
1. Apr 6, 2005
### laker_gurl3
thanks so much for any help..work and formula used would be appreciated...
A record of diameter 30cm roates on a turntable at 33.3r/min.
a.) How fast is the outside edge of the record moving?
b.) how many times as fast would it move if the frequency were raised to 78 r/min.?
2. Apr 6, 2005
### Gale
a) if the whole record moves at 33.3 revs per min, then a point on the outside edge does as well, which means that point has to go around the circumfrence (C) of the record within the minute, your speed= C/min.
b) same idea as part a, change the frequecny, and then compare.
3. Apr 6, 2005
### laker_gurl3
so i did this out..for A.) i got 3138m/s
for B.) i got 7351m/s, therefore it's 2.34 times as fast...is that correct?
4. Apr 7, 2005
### Gale
ok ya, i mean it had to go around the circumfrence 33.3 times per minute, but thats what you did, so good. Those are the numbers i got, except your units are wrong, its cm/min not m/s.
5. Apr 7, 2005
### dextercioby
Gale,i get double for the first number...
$$v=\omega R \ [m \ s^{-1}]$$
R=0.3m
$$\omega=2\pi \nu=\left(2\pi \ \mbox{rad}\right) \left(\frac{33.3}{60} \ Hz \right) \simeq \frac{200\pi}{180} \mbox{rad} \ s^{-1}$$
Ergo
$$v\simeq \frac{\pi}{3} m \ s^{-1} = \frac{6000\pi}{3} cm \ (min)^{-1}$$
which is double that the # you referred to in post #4.
Daniel.
EDIT:As Gale pointed out,the radius is only 0.15m.So that explains the incorrect result i got.
Last edited: Apr 7, 2005
6. Apr 7, 2005
### Gale
you got double because you let R=.3 whereas .3 is the diameter.
7. Apr 7, 2005
### dextercioby
****. :rofl: :tongue2:
Daniel. | {"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": 0.9084591269493103, "perplexity": 7105.118583111714}, "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/1476988719877.27/warc/CC-MAIN-20161020183839-00330-ip-10-171-6-4.ec2.internal.warc.gz"} |
https://www.physicsforums.com/threads/solving-circuit-using-laplace-transforms.616868/ | # Solving circuit using Laplace Transforms
1. Jun 27, 2012
### perplexabot
Hi all. I need to find the voltage across the inductor. I begin by solving for the current in the inductor. I first solved a circuit using differential equations (with mathematica) and achieved an answer for current in inductor of: iL(t) = E^(-5 t) (-0.75 + 1.25 E^(4 t)
Later, I tried to solve the same circuit using Laplace transforms and was not able to yield the same answer (or anything close). The original circuit and my approach for solving the circuit using Laplace transforms is attached as a pdf file. In the pdf file, I am attempting to solve for the current in the inductor. I get an equation for iL(s), however, when I take the inverse laplace, the answer looks nothing like my diff-eq iL(t). Please let me know where I am going wrong. Hints are preferred over answers. Thank you.
#### Attached Files:
• ###### laplacetry.pdf
File size:
421.8 KB
Views:
133
2. Jun 27, 2012
### the_emi_guy
In your loop 2 equation the voltage drop across inductor should be (i2)sL.
3. Jun 27, 2012
### perplexabot
WOW, you are so right. I can't believe I didn't see that. Thank you so much. I will give it another go. Hopefully I will not run into another error. Thanks again.
4. Jun 28, 2012
### perplexabot
Thanks the_emi_guy. That simple fix gave me the exact answer.
5. Jun 28, 2012
### the_emi_guy
You're welcome
6. Jun 28, 2012
### perplexabot
I am now trying to solve the circuit by hand using differential equations. I have attempted it twice and went over it many times but have not achieved the correct answer (i am close though). I may upload my attempt tonight and hopefully you (or someone else) may help me with that too. | {"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": 0.9145398139953613, "perplexity": 973.1290433234939}, "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/1518891812247.50/warc/CC-MAIN-20180218173208-20180218193208-00754.warc.gz"} |
https://www.europeanproceedings.com/article/10.15405/epsbs.2021.04.55 | # Manufacturing Industry Modernization As The Basis For Digitalization Of The Economy
## Abstract
The study's purpose is a theoretical and practical substantiation of the technological modernization importance for the industrial sector of the national economy in the light of digitalization. The unreadiness of the national economy for Industry 4.0, due to the Industry 3.0 stage's incompleteness, is substantiated. In particular, it is due to a high degree of depreciation of fixed assets in the manufacturing industry. Because digital tools are adapted for innovative equipment, full-scale digitalization creates a threat of lagging for countries that have not undergone equipment modernization. To assess the impact of technological modernization of the industrial sector on the level of digital development of territories, the authors built an ordered logit model based on data from 85 regions of Russia for 2017. As an endogenous variable, we used the digital development levels of Russian regions obtained by clustering territories using Ward's method. The clustering was based on the calculation of the International Digital Economic and Society Index for Russia's regions. The results obtained during the modeling are consistent with the theoretical provisions of the neoclassical model of economic growth by Solow and prove the high impact of modernization of the manufacturing industry on the level of digital development of territories, which determines the prospects for the transition of the national economy to Industry 4.0.
Keywords: Digitalizationmanufacturing industryordered logit modelregional economysmart benchmarking
## Introduction
The digital revolution and the emergence of Industry 4.0 have led to the transition to a neo-industrial model of economic development, the main prerequisite for implementing the full-scale introduction of "smart production". This means the integration of digital technologies into production processes based on "smart machines", as well as the creation of information platforms to manage the entire product life cycle. As a rule, Industry 4.0 is mentioned in the context of industry computerization based on the introduction of cyber-physical systems. In such a system, sensors, equipment, and information systems are connected throughout the entire value chain, extending beyond a single enterprise or business.
At the same time, having a significant impact on the rate of economic growth (Akinwale et al., 2019; Zhou & Luo, 2018) digital and technological innovations cannot be identified within the framework of the traditional classification of factors in terms of territorial development, produced at the end of the twentieth century by Krugman (1993), the founder of new economic geography, Nobel laureate of 2008. It is about dividing the entire set of competitive advantages of territories into factors of the first and second nature.
In this case the factors of the "first nature" that exist independently of human activities include the provision of natural resources, geographical location, including the border position on the routes of global trade, which reduces transport costs. The factors of the "second nature" are the advantages created by the activities of man and society: the agglomeration effect, human capital, institutions contributing to the improvement of the business climate, population mobility, the diffusion of innovations, etc. It is known that the presence of factors of the first nature and the development of factors from the second nature group is the cause of heterogeneous socio-economic development, which often leads to divergence of territories. This is especially true for countries with large territories like Russia. As it was noted by Barinova & Zemtsov (2020, p. 10) "Russia's large territory and the mix of natural and economic conditions predetermine strong regional differentiation".
In accordance with the meaningful characteristics belonging to the two groups of development factors, digitalization cannot be attributed to either of them. In this case, digitalization, like information, cannot be decreased in the process of being used by individuals (the principle of limited economic resources does not work). In this we see the dichotomous nature of the digitalization process as a factor in the development of the territory. Penetrating into all spheres of life and transforming all sectors of the economy, digitalization, on the one hand, provides all territories, regardless of their starting level of development, significant opportunities for economic growth. On the other hand, its absence at the present time can cause invaluable harm to any economy, even one rich in raw materials. Thus, an unforeseen negative consequence of the lack of digital work skills in individuals and the physical limitation of their access to the global network has led to the almost complete stop of educational processes in a number of peripheral schools during the pandemic Economists have long proven the high impact of human capital on economic growth, a decrease in which will be objectively recorded in peripheral territories not covered by digitalization (Mankiw et al., 1992).
Summing up the above, we emphasize that the phenomenon of digitalization simultaneously has a colossal potential for both stimulation and degradation of territorial development. Therefore, the mere existence of the advantages of the digital economy can both reduce spatial gaps in levels of development, and significantly increase them.
Digitalization issues in Russia have become an object of increased attention of both business and government authorities and the scientific community after the adoption of the program called "Digital Economy of the Russian Federation” by the Government of the Russian Federation on July 28, 2017. Influencing all areas of economic development, digital advantages are being studied by scientists in the field of agriculture (Shamin et al., 2020), financial system (Kiyutsevskaya, 2019), public services (Zhuk & Fursa, 2019), wholesale and retail trade (Kupriyanovsky et al., 2016). At the same time, scientists emphasize that the manufacturing sector has the main multiplier effect on economic growth (Inozemtsev, 2010).
Thus, the share of the manufacturing sector in the sectoral structure of Russia's GDP is equal to 12.8% (1st place) according to statistics for 2019. We believe that both the increase in the competitiveness of the national economy and, in general, the rate of economic growth of the country depend on the development of this sector.
At the same time, as it was noted by Urasova (2019), a significant slowdown in the development of industry in Russia is associated with the discrepancy between modern software and existing equipment at most enterprises and organizations. This conclusion seems to be objective and timely, and is confirmed by the official data of Rosstat on the degree of wear and tear of machinery and equipment in the national economy, which at the end of 2018 constituted 59.6% of the total volume of fixed assets (Federal State Statistics Service of Russia. (2020, April 28). https://gks.ru/free_doc/new_site/business/osnfond/STIZN_ved.htm) . Due to the fact that digital tools (RFID tags, ERP systems, cloud services, etc.) are adapted for innovative equipment, full-scale digitalization creates a threat of lagging behind countries (including Russia) that have not undergone equipment modernization.
Thus, the actual problem of full digitalization in the industry of the national economy is the fact that it is not ready for Industry 4.0.
## Problem Statement
The objective of the study is to build an ordered logit model that allows interpreting the modeling results for an endogenous variable in the form of a rank scale. In this study, the ranking scale is represented by the digital development levels of Russian regions.
## Research Questions
The main research issue is to quantify the likelihood of territories' transition to a higher level of digital development. This type of assessment is possible based on the analysis of the marginal effects of exogenous variables.
## Purpose of the Study
The aim of the study is to assess the impact of technological modernization in the industrial sector on the level of spatial digital development, which determines the prospects and opportunities for the transition of the national economy to Industry 4.0.
## Research methodology
The International Digital Economy and Society Index (I-DESI) was chosen as an assessment tool for the digitalization level of the regions in the Russian Federation to conduct the empirical part of the study. I-DESI is developed on the basis of the DESI index for the member countries of the European Union and assesses the level of the economy and society digitalization both in individual countries of the European Union and the European Union as a whole.
I-DESI allows to develop adequate development directions and adjust the tools for implementing policy in the field of the digital economy and society. Therefore, in terms of content, I-DESI is suitable for assessing the readiness of Russian regions for the transition to a digital economy.
In general, I-DESI is built on the basis of five main parameters:
• Communication (the parameter evaluates the implementation of the broadband network infrastructure and its quality);
• Human capital (a parameter that measures the level of skills of the population required to take advantage of the digital society);
• Internet use (the indicator takes into account various types of activities in demand by the population on the Internet);
• Integration of digital technologies in business (it measures the digitalization of business and the use of remote sales channels, and also reflects the level of digitalization penetration into the industrial sector);
• Digital public services (the indicator reflects the scale of electronic services in the public sector, with the main focus made on the development of "electronic government" - e-Government).
An ordered logit model was built to assess the impact of technological modernization in the industrial sector on the level of spatial digital development, which determines the prospects and opportunities for the transition of the national economy to Industry 4.0. A model of this type is used when the endogenous variable is measured on a rank scale. At the same time, situations where the results of modeling in accordance with the meaningful meaning should be presented in a rank scale are quite common. So, for example, scientists solve the following research questions using the ordered logit model:
• whether the poorest income quintile would benefit most from programs aimed at increasing their access to financial services (Abraham, 2018);
• examination individual and contextual factors of happiness and life satisfaction in the happiest countries in the world (Sujarwoto et al., 2018);
• research of patients' propensity to consume private healthcare services (Meleddu et al., 2020).
The considered model has the following form:
$y i * = x i ' β + ε i ,$
where ${x}_{i}$ – a vector of explanatory variables, $\beta$ – a vector of coefficients, ${\epsilon }_{i}$– a random component distributed according to the normal law.
The variable ${y}_{i}^{\mathrm{*}}$ - itself is an unobservable value, which is related to the observed discrete variable value ${y}_{i}$ by the following relations:
$y i = 0 , i f y i * ≤ 0 1 , i f 0 < y i * ≤ μ 1 2 , i f μ 1 < y i * ≤ μ 2 … J , i f μ j - 1 ≤ y i *$
where ${\mu }_{\mathrm{1}},\mathrm{}{\mu }_{\mathrm{2}},\mathrm{}\dots ,\mathrm{}{\mu }_{j-\mathrm{1}\mathrm{}}$ - threshold values, J – the number of possible ordered values.
Then the probability of a certain outcome can be obtained as follows:
$Pr y i = j x i = F μ j + 1 - x i ' β - F μ j - x i ' β .$
The model parameters are estimated using the maximum likelihood method. The logarithmic likelihood function will have the following form:
$ln L β , μ 1 , … , μ j - 1 , y , x = ∑ i = 1 N y i j ln P r y i = x i .$
The ordered values of the level of spatial digital development were taken as an explained variable (1 is the lowest level of digital development, ... 5 is the highest level). The level of digital development is assigned to a territory based on the results of cluster analysis according to the regional development indicators of a digital society relevant to the I-DESI index, corresponding to 5 areas of research: communication, digital skills, use of the Internet by citizens, integration of business technologies, digital public services.
The selection of indicators for cluster analysis is based on the following requirements:
• the requirement of representativeness, according to which the indicators should most fully reflect the relevant aspects of the regional development;
• the requirement of accessibility, according to which the indicators involved in the analysis should be included in the list of official statistical indicators - either calculated from the values of the latter, or published in open sources of information. A prerequisite for choosing indicators is the availability of data for all regions within the relevant year. The use of averaged values based on previous periods instead of missing data is often used in this kind of research, but, in our opinion, this is undesirable, since the level of distortion of the results increases;
• the requirement of objectivity, according to which the indicators used should adequately reflect the state of the analyzed aspect of the regional development. The use of indicators in other assessment methods was taken into account, as well as their inclusion in the number of indicators reflecting the effectiveness of the state policy implementation;
• the requirement to take into account regional characteristics, according to which indicators reflecting factors that have the most significant impact on the life of the population and the region's development should be selected for assessment and forecasting.
Clustering for the purpose of dividing territories according to the level of digital development is carried out by implementing the following steps:
• Determination of the set of variables by which the objects in the sample are estimated and the normalization of the variables values using a linear transformation:
$y x = x - x m i n x m a x - x m i n$
• Calculation of the values of the similarity extent between objects;
• Application of the cluster analysis method to create groups of similar objects (clusters);
• Presentation of analysis results.
We presented conclusions and recommendations to determine the directions of regional development based on using the concept of "smart" benchmarking, which we described in detail earlier (Dubrovskaya et al., 2018). A feature of "smart" benchmarking is the preliminary identification of structurally similar territories, based on which the development priorities of the object under study are determined by introducing the successful experience of regions that are identical for it. From the substantive point of view, this means that for objective reasons, in the national context, not all indicators of the development of such leading regions as, for example, Moscow or St. Petersburg, can be achieved in practice by outsider regions in the foreseeable future. For this study, identical regions are considered as territories from the same cluster group. Accordingly, recommendations for improving development indicators are formed based on taking into account the positive experience and achievements of the leading regions of a particular group.
## Data
This study is based on statistical data from the Federal State Statistics Service for 85 constituent entities of the Russian Federation for 2017.
The authors have developed a system of indicators that correspond to the methodology for calculating the I-DESI index to assess the development level of the region's digital environment (Table 1 ).
The system of indicators described above is served as conducting a cluster analysis basis to typologise the Russian Federation regions according to the level of their digital development. The grouping results served as the basis for introducing an ordered logistic regression explainable variable. Statistical data used as regressors to assess the impact of technological modernization of the industrial sector on the level of regional digital development are shown in Table 2 .
Indicators high, middlehigh, middlelow, and low were calculated as the ratio of the average number of employees engaged in economic activities of different technological levels to the average number of employees in the full range of organizations. According to the level of technological development, the division of activities is carried out in accordance with the list of high-, medium- and low-tech economic activities (Eurostat. Statistics Explained. (2018, July 8). https://ec.europa.eu/eurostat/statistics-explained/index.php/Glossary:High-tech_classification_of_manufacturing_industries) developed by Eurostat based on Rosstat data.
At the same time, high-tech types of economic activity include: production of medicines; manufacture of computers, electronic and optical products; production of aircraft. Medium-tech high-level types of economic activities include: production of chemicals; manufacture of electrical equipment; repair and installation of machinery and equipment. Medium-tech low-level types of economic activities include: copying of recorded media; production of coke and petroleum products; manufacture of rubber and plastic products. Low-tech economic activities include: food production; beverage production; production of tobacco products; manufacture of textiles; production of leather and leather products; wood processing.
## Findings
The authors carried out a cluster analysis using the Ward's method, five compact and well-separated clusters were obtained, which are quite amenable to economic interpretation. The quantitative characteristics of the obtained groups of regions are presented in Table 3 .
According to the results obtained, the regions of the “Leaders” group (Moscow, Moscow Region, St. Petersburg) have the highest values for all five indicators. The largest number of regions (39 regions) were included in the “catching-up type” group. In general, the level of digital development for the regions of this group is below average. However, in comparison with the regions of the “middle link”, the territories of the “catching-up” group are characterized by a high share of the population using the Internet. In the group of regions with an average level of digital development called "Middle link" (including such regions as the Udmurt Republic, Oryol region, the Republic of Mordovia and others), the average value of the share of people employed in the ICT sector is second only to the group "Leaders". The fifth group includes 15 regions lagging behind in all parameters of the digital environment development. The average values of digitalization indicators in the structure of the I-DESI index for five groups of regions are shown in Figure 1 .
Further, based on the clustering results, an endogenous variable was determined, which takes the value 1 if the region belongs to the group of regions "Lagging type", 2 - "Catching type", 3 - "Middle link", 4 - "Progressive", 5 - "Leaders ".
The ordered logit model coefficients were estimated using the Stata 13 program and the maximum likelihood method. The obtained simulation results are shown in Table 4 .
According to the simulation results, the level of digital development in regions, which determines the prospects and opportunities for the transition of the national economy to Industry 4.0, is more influenced by the state of the high-tech economic activity types. The higher the share of people employed in high-tech activities, the higher the likelihood of the region's transition to a higher digital development level.
In addition, the transition of regions to a higher level of digital development at the 5% level of significance is influenced by such indicators as the share of those employed in medium-tech low-level types of economic activities and the level of costs for technological developments, and at the 10% level of significance we can observe the share of those employed in medium-tech high level of types of economic activities.
Next, we analyzed the marginal effects of exogenous variables to determine the likelihood of a territory transition to a higher level of digital development. In other words, we calculated the percentage increase in the likelihood of moving to the next level of digital development if one of the independent variables changes, and the rest remain constant. The results of evaluating marginal effects are shown in Table 5 .
The obtained results indicate that the regions of group 2 (catch-up type) have the highest probability of transition to the next level of digital development: an increase in any of the factors increases the probability of transition to group 3 (middle link) by more than 60%. For regions from the 1st group (lagging type), the greatest effect (18.5%) is generated by a change in the middlelow indicator (the share of employed in medium-tech low-level types of economic activity). This is quite consistent with the theoretical provisions that we disclosed earlier and indicating that outdated equipment and the lag in the development of basic sectors of the economy do not allow full-scale implementation of digital innovations.
In addition, the results obtained are in line with the main conclusion of the neoclassical economic growth model by Solow. According to his model, an increase in capital capacity (in this case, in the field of such low-tech economic activities as the production of food products, drinks, textiles, etc.) can provide high rates of economic growth until the territory reaches a balanced growth path.
Thus, as a result of convergence, regions of group 1 (lagging type) have a high chance of moving to group 2. It is rather difficult for the regions of group 3 (middle link) to move to a higher level of digital development (catching-up type): changing factors increases the probability of transition by an average of 8%.
This conclusion is consistent with the provisions of the path-dependence problem, according to which it is almost impossible for middle-class countries to make a breakthrough in economic development. And isolated cases of such breakthroughs (Japan, South Korea, etc.) are the exception rather than the rule.
Regions of the 4th group (catching-up type), for the transition to Leaders, need to increase the share of those employed in high-tech types of economic activity (the probability of transition is 22.6%), which is also consistent with the conclusions of the Solow’s model with technical progress. So, according to the model, developed economies (in our case, regions of groups 4 and 5), which are on the balanced growth path, can increase the rate of economic growth only due to technological progress (in our model, this is the indicator “the share of people employed in high-tech economic activities”).
## Conclusion
The topic of digital modernization of the manufacturing industry is updated as a key factor in the transition of the economy to Industry 4.0 in the research. In the course of the study, using the example of Russian regions, it was proved that the likelihood and possibility of increasing the levels of digitalization in various territories depends on the current state of their economic and innovative development. At the same time, not all territories are ready for digital modernization. Thus, a number of regions must at least overcome the lag in the development of basic sectors of the economy; most regions need equipment modernization to start implementing digital innovations; and a full-scale digitalization in the leading sectors of the manufacturing industry takes place only in a few of the most developed regions. Thus, the findings are consistent with the provisions of the neoclassical growth theory that the growth trajectories of heterogeneous economies (which regional economies are) tend to their own balanced growth trajectories. And this is important to consider when developing regional digital development strategies.
We see the continuation of this research in detailing individual territories' data from the standpoint of "smart" benchmarking. So, at present we are developing a system of priorities for digital development for the Perm region based on comparing the indicators of its digital development with the parameters of identical regions of a single cluster group. These priorities can be the basis for the formation of strategic directions and programs for digitalization of the Perm region economy.
## Acknowledgments
The reported study was funded by RFBR according to the research project № 19-010-00449
## References
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3. Barinova, V. A., & Zemtsov, S. P. (2020). Inclusive growth and regional sustainability of Russia. Regional Research of Russia, 10, 10–19. https://doi.org/10.1134/S2079970520010025
4. Dubrovskaya, Yu. V., Kudryavtseva, M. R., & Kozonogova, E. V. (2018). “Smart” benchmarking as a basis for strategic planning in regional development. Economic and Social Changes: Facts, Trends, Forecast, 11(3), 100–116.
5. Inozemtsev, V. L. (2010). Modernization of Russia in context of globalization. World economy and international relations, 2, 90-103.
6. Kiyutsevskaya, A. M. (2019). Fintech: Current trends and challenges for monetary policy. Voprosy Ekonomiki, 4, 137-151.
7. Krugman, P. (1993). First Nature, Second Nature, and Metropolitan Location. Journal of Regional Science, 33(2), 129–144.
8. Kupriyanovsky, V. P., Sinyagov, S. A., Namiot, D. E., Utkin, N., & Dobrynin, A. P. (2016). On retail trade in the digital economy. International journal of open information technologies, 4(7), 1-10.
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10. Meleddu, M., Pulina, M., & Scuderi, R. (2020). Public and private healthcare services: What drives the choice? Socio-Economic Planning Sciences, 70, 100739.
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16 April 2021
#### Article Doi
https://doi.org/10.15405/epsbs.2021.04.55
#### eBook ISBN
978-1-80296-104-1
#### Publisher
European Publisher
105
-
1st Edition
1-1250
#### Subjects
Sustainable Development, Socio-Economic Systems, Competitiveness, Economy of Region, Human Development | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 11, "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": 0.3394375443458557, "perplexity": 1676.3497428224896}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710685.0/warc/CC-MAIN-20221129031912-20221129061912-00075.warc.gz"} |
https://pos.sissa.it/128/065/ | Volume 128 - The Xth Nicola Cabibbo International Conference on Heavy Quarks and Leptons (HQL 2010) - Top Quark Physics
Understanding backgrounds towards a first measurement of the top quark pair cross-section at ATLAS | {"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": 0.9159815311431885, "perplexity": 3750.2094789363973}, "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-2020-24/segments/1590347407289.35/warc/CC-MAIN-20200530040743-20200530070743-00543.warc.gz"} |
https://chemistry.stackexchange.com/questions/40840/how-to-calculate-the-amount-of-citric-acid-to-neutralise-the-ph-within-wastewate | # How to calculate the amount of citric acid to neutralise the pH within wastewater?
We have an effluent tank, with a consent to discharge at between 5.5 - 11 pH, the tank holds 100000 liters of dirty water.
When the pH reaches 10.5 we add citric acid to bring the pH down. How many liters of citric acid with a pH of 2.2 should we add to the system to bring the pH down to around 7. We always end up putting too much in then add caustic to bring it back up.
Gotta start with my favorite formula: $$Q = CV$$
$$C_\textrm{eff}V_\textrm{eff}+C_\textrm{acid}V_\textrm{acid} = C_\textrm{out}V_\textrm{out}$$
$$(10^{-10.5}~\mathrm{mol/L})(10^5~\mathrm{L})+(10^{-2.2}~\mathrm{mol/L})V_\textrm{acid} = (10^{-7}~\mathrm{mol/L})(10^5+V_\textrm{acid})$$
$$V_\textrm{acid} = 1.51~\textrm{L}$$
• Well, we normally add somewhere in the region of 200 litres of acid, the pH then drops below our bottom end (5.5). So are you saying to add 1.58 litres of acid in total? – Daniel Bridges Nov 16 '15 at 19:27
• Yes, it appears that the amount of acid required is extremely small compared to the total volume (I was honestly expecting something on the order of 100-300L, so it was surprising to get ~1.5L) – costrom Nov 16 '15 at 19:34
• Does it make any difference that this is all being diluted with water? The tank gets filled from the drains within the factory which normally runs at about 6.4pH, the pH of the effluent tank only gets so high when we carry out internal cleaning with the caustic ph of about 14.4. 1.5litres seems incredibly small – Daniel Bridges Nov 16 '15 at 19:38
• Well the "math" does lie in this case. How much citric acid to add depends on what else is in the dirty water. So getting a pH of 10.5 with NaOH is different than getting a pH of 10.5 with NH3. It really seems that you should do a quick test on a sample of the water. You wouldn't need super accuracy. It would seem that you could just count drops of citric acid solution. So amount of citric acid depends on what other "stuff" is in the dirty water, and how much. – MaxW Nov 16 '15 at 22:07
• @Martin-マーチン The highest pKa of citric acid is about 6.4 (per Wik). For solutions with pH above about 7.5 to 8, citric acid will behave essentially as a (triprotic!) strong acid. Beyond that, at the target pH of 7, with a second-highest pka of ~4.8, it will still behave roughly as a diprotic strong acid, though with some buffering coming into play from that 6.4 pKa. – hBy2Py Apr 2 '16 at 12:25 | {"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": 0.41739150881767273, "perplexity": 1766.4366047510548}, "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-2019-18/segments/1555578733077.68/warc/CC-MAIN-20190425193912-20190425215912-00543.warc.gz"} |
https://dsp.stackexchange.com/questions/43767/inverse-dtft-of-left-sided-sequence | # Inverse DTFT of left-sided sequence
I am pretty new to inverse Fourier transforms and I would like to ask a question. Does anyone know how to bring back to the "sequence domain" this relation below? In other words, get the inverse DTFT of this expression? (Given that C, D and $a$ are constants and you know them):
$$\frac{C \cdot e^{-j \omega}+D}{(1 - a \cdot e^{ j \omega })^2}$$
• Hey! No its not a typo. – Taiwaninja Sep 15 '17 at 18:11
• set $z = e^{j \omega}$ and see what you get. – robert bristow-johnson Sep 15 '17 at 18:30
• robert, if I use z instead, may I use properties from z transform without any problems? – Taiwaninja Sep 15 '17 at 18:40
• Note that there's not only one correct solution but two. Depending on the value of $\alpha$ you get two different sequences. For $\alpha>1$ you get a right-sided sequence, and for $\alpha<1$ you get a left-sided sequence. – Matt L. Sep 16 '17 at 19:19
There seems to be a mistake in your derivations, the following code shows the correct one for $|\alpha| < 1$ , as indicated by @Matt.L $: N = 128; % simulation length (choose large enough) n = -N : 2; % simulation time span C = 1.5; % set some values D = 2.78; a = 0.33; % a is for alpha % x = -(n-2).*C.*(a.^(-n+1)).*stepfun(-n+2,0) + ... % -(n-1).*D.*(a.^(-n)).*stepfun(-n+1,0); x = zeros(1,130); % use the explicit code as stepfun() has problem with n. for n = -N:1 x(n+N+1) = -C*(n-2)*(a^(-n+1)) - D*(n-1)*(a^(-n)); end M=2000; % Select a FFT length for demonstration purposes F=fft(x,M); % compute the DFT of x[n] so obtained w = linspace(0,2*pi-2*pi/M,M); % choose DFT frequency samples H = (C*exp(-1j*w)+D)./((1-a*exp(1j*w)).^2); % Evaluate the given DTFT figure,plot(w,abs(H));title('H'); % compare the magnitudes of DTFTs figure,plot(w,abs(F));title('F'); % Phases will be different as this % is an acausal sequence. Derivation of the result for the left-sided sequence$|\alpha|< 1$case) is as follows: Intuition plays a central for getting the answer as clean as possible which involves inverse Fourier transforms. In this example we shall use those three fundamental Fourier transform properties. 1-$x[n] \leftrightarrow X(\omega) \longrightarrow y[n]=x[-n] \leftrightarrow Y(\omega) = X(-\omega) $2-$x[n] \leftrightarrow X(\omega) \longrightarrow y[n]=nx[n] \leftrightarrow Y(\omega) = j \frac{d X(\omega)}{d\omega} $3-$x[n] \leftrightarrow X(\omega) \longrightarrow y[n]=x[n-d] \leftrightarrow Y(\omega) = e^{-j \omega d} X(\omega)$Begin by $$x[n] = a^n u[n] \longleftrightarrow X(\omega) = \frac{1}{1 - a e^{-j \omega} }$$ Let$y[n]=x[-n]=a^{-n} u[-n]$then$Y(\omega)= \frac{1}{1-a e^{j \omega}}$Apply second rule:$z[n] = n y[n] = n a^{-n} u[-n]$then$Z(\omega) = \frac{-a e^{j \omega}}{(1-a e^{j \omega})^2}$Apply linearity:$ w[n] = -a^{-1} z[n] = - n a^{-1} a^{-n} u[-n]$then$ W(\omega) = \frac{e^{j\omega}}{(1-a e^{j \omega})^2}$Apply shift property on$w[n]$to get rid of the numerator exponential.$v[n] = w[n-1] = - (n-1) a^{-1} a^{-(n-1)} u[-(n-1)]$then$ V(\omega) =\frac{1}{(1-a e^{j \omega})^2}$Now apply shift property and linearity to$v[n]$such that the resulting DTFT will be $$H(\omega) = \frac{ C \cdot e^{-j \omega} + D} {(1-a e^{j \omega})^2} = \frac{ C \cdot e^{-j \omega}} {(1-a e^{j \omega})^2} + \frac{ D} {(1-a e^{j \omega})^2}$$ which implies that $$h[n] = C v[n-1] + D v[n]$$ hence we get$h[n]\$ as:
$$h[n] = C \left( - ((n-1)-1) a^{-1} a^{-((n-1)-1)} u[-((n-1)-1)] \right) - D \left( (n-1) a^{-1} a^{-(n-1)} u[-(n-1)] \right)$$
simplify to get the result: $$h[n] = C (-n+2) a^{-n+1} u[-n+2] + D (-n+1) a^{-n} u[-n+1]$$
• \@Fat32 thank you very much. Now it makes sense, I could not duplicate the result as it was before but now I get it. Thank you so much! – Taiwaninja Sep 15 '17 at 22:53
• @Taiwaninja now there is also a derivation... – Fat32 Sep 16 '17 at 20:39
• @Taiwaninja Nice to see that I can help! Please don't hesitate to upvote and select the answer if it helped you, as this will help other people trust the answer as well and moreover the question will be closed properly... – Fat32 Sep 18 '17 at 9:50 | {"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": 0.7871496677398682, "perplexity": 2503.078084624843}, "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-2019-30/segments/1563195524290.60/warc/CC-MAIN-20190715235156-20190716021156-00125.warc.gz"} |
http://winassist.org/thread/94222/Palm-PDA-lt-gt-Outlook-sync-software-that-DOES-NOT-REQUIRE-admin-privileges.php | Windows Support Forum
# Palm PDA<->Outlook sync software that DOES NOT REQUIRE admin privileges
Q: Palm PDA<->Outlook sync software that DOES NOT REQUIRE admin privileges
Hello all,
I've been looking for some time for a $subject but I can't find anything so far This f... sucker of PalmDesktop REQUIRES to run as an admin in order to do anything, with all the security problems that this implies... So, do I have a solution other than changing the ACLs on all of the PalmDesktop directory, ie a correctly written piece of software that can do the same things as PalmDesktop, but as a user? Relevancy 100% Preferred Solution: Palm PDA<->Outlook sync software that DOES NOT REQUIRE admin privileges I recommend downloading and running Reimage. It's a computer repair tool that has been proven to identify and fix many Windows problems with a high level of success. I've used it in the past to identify and fix everything from blue screens (BSOD's), ActiveX errors, corrupt files and processes, dll/exe/sys errors, recover lost memory, Windows update problems, defragging, malware removal etc. You can download it direct from this link http://downloadreimage.com/directdownload.php. (This link will automatically start a download of Reimage that you can save to your computer.) A: Palm PDA<->Outlook sync software that DOES NOT REQUIRE admin privileges I have found that you only have to install it under Admin , mine all run fine After I revert the user back to normal. eg. I add my wife " User Limitied " to the Admin group . Install the software logged on her account . Hotsync. then Remove her from Admin . It's a small pain , but it works. http://www.techspot.com/community/topics/palm-pda-outlook-sync-software-that-does-not-require-admin-privileges.45675/ Relevancy 141.67% Hello all, I've been looking for some time for a$subject but I can't find anything so far
This f... sucker of PalmDesktop REQUIRES to run as an admin in order to do anything, with all the security problems that this implies... So, do I have a solution other than changing the ACLs on all of the PalmDesktop directory, ie a correctly written piece of software that can do the same things as PalmDesktop, but as a user?
A:Palm PDA<->Outlook sync software that DOES NOT REQUIRE admin privileges
I have found that you only have to install it under Admin , mine all run fine After I revert the user back to normal.
eg. I add my wife " User Limitied " to the Admin group . Install the software logged on her account . Hotsync. then Remove her from Admin .
It's a small pain , but it works.
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On my old computer I had Eudora Internet software (freeware) to synch the email to my palm. I tried downloading it to my new computer, but nothing happens when I sync. Everything else works (calendar, contacts, etc), but the email needs a third party to sync and the Eudora is doing nothing. It's downloaded on my laptop (XP), but I can't figure out how to get it into the install conduit or to get it to run.
Is there a simple fix to get it going, or does anyone have a suggestion for a better freeware software to do this?
I don't want to buy anything because I'm probably going to switch from my plam/phone combo to a smartphone soon, and I'm guessing the software will be different.
Karen
A:Which software to use to sync email to my palm?
Hiya
Have you tried all of this:
http://eudora.com/techsupport/kb/2216hq.html
and if that doesn't help, right at the bottom are some other links. If you get any error's or it just stops at a certain point, can you tell us what and where?
Also, and not sure if it will matter, but what is the version of palm you're using?
Regards
eddie
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Am not able to sync my Palm (IIIc) to Outlook. Just set it up with new computer w/XP. Was able sync Palm & Outlook on previous computer that ran ME. Any suggestions?
A:How to Sync Palm to Outlook
Hi there.
Outlook?
Palm software?
Synching software?
What DOES happen when you synch?
What settings did you choose for synching?
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Hi,
I just signed up for MS Outlook Live. In doing so my msn account has different mail, calendar, tasks, and contact folders to actively sync with my msn account. This is great; however, it did create one small problem which I know can be fixed (i just don't know how to fix it). I sync my PDA with my outlook; however, being that my new Outlook Live folders are not my default sync folders now... my PDA will not sync with my accounts correctly. Does anyone know how to set up your Outlook Live folders to sync with your PDA?
Thank you,
McCoyNet
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Is there a way I can sync my Palm Pilot with Outlook 2010?
Its a Palm M130
Thanks
-Russell (RJ)
A:Sync Palm with Outlook 2010
You can try the newest version of palm desktop, it might not work though.
http://www.sevenforums.com/microsoft-office/57659-sync-palm-outlook-2010-a.html
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Hello We are using Exchange server and outlook client I am having problems with recurring sync to Outlook pilot palm meetings with people that Outlook to palm pilot sync invite me for a meeting from other parts of the world within our company We did a test where the person from our China office put the meeting on my calendar for Wednesday PM my time AM Thursday in China It shows up fine in outlook before I sync however the date somehow changes to Thursday PM my time after I sync it with my palm It would appear Outlook to palm pilot sync that the communications between the Palm Pilot and Outlook is flawed It does the time calculation correctly but then it uses the recurring day of Thursday China time instead of the using my local date I already checked the time zones and they are already set This only happens on recurring meetings and doesn t happen for a one time meeting The outlook date is still correct but the palm pilot date is the one that changed I m using XP Has anybody seen this before Is Outlook to palm pilot sync this outlook problem or palm problem nbsp
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The owner of a handspring PDA wants to sync it with Outlook... (he's
I'm admin on the machine, but have no Outlook account set up as I don't
use it.
To install the sync software requires admin rights: Once I get to this
stage, it prompts me to set up an Outlook account as the person
installing it, but its the user's account that needs the sync with
Outlook!
to that user so he can install software?
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I have just purchased a new laptop running windows 7 64 bit and Office 2010 for Home and Business. I installed the lates Palm desktop software in an effort to sync my Tungsten E (2004) with Outlook. No dice. One recommendation was to purchase a USB/Moschip to link with IR. I would like to know if anyone is developing drivers to overcome the 2010 issue. I do not want to load an older version of Outlook.
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What you could do is turn on the guest account and have them, use that? then just keep one ADMIN account for you to use/log into?
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Ok I've got a question about synchronizing my handheld. I currently have it setup to synchronize with the palm software, but I would like to change this to synchronize with Outlook instead. I know this is possible, but I just can't seem to find it in the options anywhere. If anyone has done this or know how please let me know. I am using a Handspring Visor Deluxe. Thank you ahead of time
A:Synchronize with Outlook, instead of Palm Software
In my version of the Palm Desktop (4.0.1) you can do the following:
1) Run Palm Desktop
2) Click on Hotsync....Custom
3) Highlight Mail and click Change....
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I am the only user on this PC and User Account type indicates that I'm the "Administrator".
Hello and welcome!
Sometimes you have to run the installation file and deliberately make it "Run as Administrator" by right clicking on the downloaded file and selecting this option. Not sure if this is the case with Google Earth but worth a try.
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Managed to create a new Admin-level user.
No go. Same problem. Will not run anything - not enough permissions?!
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A:My Admin user name is corrupted so now PC has NO admin privileges
See Built-in Administrator Account - Enable or Disable about enabling the built-in admin account. Once you get it set up I would take a system image with third party software (aomei, eg) so you have a fallback.
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Hi.
The main (and only account) I have been using since the first beta came out had administrator privileges.
Today when I booted up I noticed that my account could no longer do things that are associated with an admin account, such as installing certain programs and writing to certain folders.
I created another account with admin rights and that account has the exact same problem. I tried removing the admin status on my account and putting it back on but that did not work.
Anyone else have this problem or have any advice on how to get my account seen as an admin account?
Hello iroden.
Check out my recent other post for a similar matter
NewSID.exe HELP!!!!!!!!!
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I have been using fusionOne services to keep my laptop and desktop in sync for Outlook 2002. The service is discontinuing this type of sync and would like to hear of available options.
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I can no longer Hot Sync my Palm Tungsten. Error message says that program is mising PalmCmn.dll. I canot reenter the software disc. Any ideas?
http://h30434.www3.hp.com/t5/Desktop-Software-and-How-To-Questions/Palm-Tungeston-E2-Hot-Sync/td-p/5646675
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Palm hasn't issued a 64 bit driver for HotSync. I can't sychronize my palm 750P with Microsoft Outlook.
Has anyone found a work-around?
Thanks,
Bob421
A:Palm 64 Bit Hot Sync Driver
I'm looking for one as well.
http://www.vistax64.com/drivers/190390-palm-64-bit-hot-sync-driver.html
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I have a Palm TX (was given it as a gift; the original owner got a BlackBerry and passed this on to me) that I am trying to sync with my PC's calendar. For now I'm using Google Calendar, and I figure I can export those events into an iCal file and then convert that as necessary, if I can figure this SD step out.
The biggest barrier is that I run Windows 7 64-bit. Palm did not create a 64-bit driver for the TX, so I cannot sync it with the USB cable. I do not have Bluetooth on my laptop so I can't use that either. I can't use WiFi sync because it requires an initial cable sync.
Is there a way to sync the calendar (and perhaps contacts) by putting some kind of file on an SD card? Or perhaps some other method?
Thanks for the help!
A:Sync Palm TX via SD Card?
I don't quite understand all this about syncing with a calendar on the internet; but, I do know a way to connect your TX to your computer via its USB sync cable and have the SD card show up as a drive letter in My Computer.
I have a TX and a Palm Treo 680 (smartphone) and I use a program I installed on the TX and the Treo 680 called Card Export. Once installed on the Palm, you connect the TX to the desktop computer via its sync cable. You then tap the Card Export icon on the TX to start that program and it displays a "connect" button. You click "connect" and the SD card shows up in My Computer as a drive letter.
I use this method to synchronize all my DOC and RTF files, about 750 of them. I also use the Treo 680 to record all my tech support calls for future reference and I use the Card Export program to copy those recordings to my desktop computer.
You might have to take your Palm to a 32-bit system and set it up there in order to install the Card Export program.
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I see references to "Microsoft Windows Mobile" that imply it can sync Outlook with cell phones but everything I can find talks about using it on handheld devices. I'm looking for PC software that will do this. I found Motorola (my cell phone brand) Mobile PhoneTools but feel that a MS product might give better connectivity to Outlook.
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Hi,
I don't use hand helds myself however a friend needs some help, he wants to be able to synchronise his palm over a LAN peer-to-peer network no server/domains... all computers are windows xp. Has already sync'd it locally on one pc and I have already installed palm software and in the sync manager chosen for both pc's usb and network. the hand held has not been locally synchronised on one pc.
If anyone can tell me how this works that will be great and e.g. if changes are made on palm will they be replicated on the network automatically onced locally sync on the original pc??? THANKS! [email protected]
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Hi, I've got a Palm Treo that I need to sync with Outlook 2003, I've tried installing/re-installing the Hotsync software and conduit from Chapura with no luck.
I've gone through the FAQ's on both Palms site and Chapura software site with any luck, so I thought I'd try here.
Here is the error from my Hotsync log:
PocketMirror® 3.1.5.6 (OEM)
-- Outlook Calendar 3.1.5.6 (OEM)
ERROR: 00008001
Unable to communicate with Outlook's OLE Automation interface.
760: PMirror
Outlook Calendar synchronization failed
-- Outlook Contacts 3.1.5.6 (OEM)
ERROR: 00008001
Failed opening Outlook interface.
475: PMirror
Outlook Contacts synchronization failed
ERROR: 00008001
Failed opening Outlook interface.
475: PMirror
-- Outlook Notes 3.1.5.6 (OEM)
ERROR: 00008001
Failed opening Outlook interface.
475: PMirror
Outlook Notes synchronization failed
*Other operations that are fine*
OK System
HotSync operation complete 28/01/2005 11:08:13 AM
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I have had a Hand Spring Visor Platinum PDA for several years. For some reason, I can no longer Hot Sync the hand held device with the PC.
After a session with a top-level tech at Palm, I was told that I would need to upgrade to a newer device. I purchased a Palm m125, and still cannot Hot Sync!
Does anyone know if WINDOWS XP Pro could have changed by automatic updates, and what will fix this? I depend on my "brain," with all of the phone numbers, names and addresses of my client base.
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Is there a way I can sync these two calendars together without going through another software?
A:Sync Goole Calendar to Palm
What is a Goole Calendar?
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I installed Palm desktop V4.1 and failed to sync my palm with PC. I got error message on palm about connection. Someone told me to install USB driver, but I did not get any hardware popup in windows. Please help me to solve it. Thanks.
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I was having trouble syncing my Palm 500 with my new laptop. A friend suggested that the existing software might not be compatible with Windows XP, so I downloaded from the Palm site, the correct software. Now, I am getting no error messages and it thinks it is syncing, but there is no exchange of data. What do I need to do?
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Well, I discovered the bad news that Windows Mobile Device Center doesn't work with Outlook 2010 if installed as 64 bit. Microsoft says to "fix" this by uninstalling Office 2010 and installing the 32 bit version! Ha! They have no plans for a real fix.
My question is are there any 3rd-party sync programs that will work with Windows 7 64 bit and Microsoft Office Outlook 64 bit and Windows Mobile 6.5 devices? I don't need to sync email but I do need to sync calendar, contacts, and tasks. And yes, I am aware that the iphone will sync with it! Silly Microsoft. I have 1.5 years left on my mobile contract with my Windows Mobile 6.5 phone, so I am stuck for now.
A:3rd party sync software for Windows 7 64 bit with Outlook 2010 64 bit?
Off the top of my head, I can't think of any 3rd party apps.
In the case that none exist, nor will MS ever get around to releasing a fix - is it possible for you to uninstall the x64 version and just install the x32 version?
http://www.sevenforums.com/microsoft-office/96705-3rd-party-sync-software-windows-7-64-bit-outlook-2010-64-bit.html
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Post the Hijack log.
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i have another vista question. it pertains to the "windows calendar" program within vista. has anyone used this program with a palm organizer?
i am having the MOST difficult time getting the program to "see" the palm pilot. you have to go through the "sync center" but it keeps telling me that "there are no new sync partnerships that can be setup on this computer".
i've barely started using vista, and already it's a total pain in the a*s.
-newreel.
http://www.techsupportforum.com/forums/f217/windows-mail-and-syncing-to-a-palm-pilot-179842.html
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I get this message whenever I try to sync the Netscape Calendar with a Tungsten E2.
Protocol Error: Handheld canceled synchronization. (4405)
The Hot Sync Manger version is 6.0.1
The Palm Desktop version is 4.1.4
The Operating System is Windows XP
A:Palm/netscape Calendar Sync Problem
Hello cat79, Welcome to BC. I'm learning here too,so maybe we can figure thos one out.I seem to find thru reading that the issue may be caused by netscape not being updated.I also found you may find something in the Hotsync log.The HotSync Log is a document generated by the HotSync Manager whenever you start to synchronize your device. It can tell you which conduits were sucessfully synchronized, which were not, and sometimes, if a conduit failed, why. To view the HotSync Log in Windows on your PCIn the System Tray (usually at the bottom right of your screen), click on the HotSync icon.Select "View Log," then select your device. This will open a browswer type window.To view the HotSync log on your E2 (this is less detailed than on PC)Go to ApplicationsTap on the HotSync iconTap on the Log buttonThe abbreviated HotSync Log appears on your screen. For a full version with detailed conduit actions and error messages, open the HotSync log on your desktop PC
http://www.bleepingcomputer.com/forums/t/65468/palmnetscape-calendar-sync-problem/
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There should be an admin account with full rights that was created when Windows was installed but it is usually only available when booting into safe mode. When safe mode starts, he should see an admin account and his account. Have him select admin and then go to control panel, user accounts. There he should be able to set up accounts and change the rights on existing accounts
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Computer at work does not allow administrator priveleges. System recovery tab also missing. Privileges still not accepted in safe mode. Computer has problems with missing files upon start.
Thanks for any help.
Richard
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Although I bought this computer new w/ XP installed and set up the original user accounts and have been able to add/remove accounts, I have had reason to wonder if I am recoginzed and the adminstrator.
I don't tend to interface with the computer at the OS level very often. I am trying to install some software that tells me that I need admin privileges and I'm having trouble installing the software, making me wonder if this might be the problem
Where do I even look for that kind of thing?
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I was trying to install a video game called Phantasy Star Online: Blue Burst on my computer. It couldn't install 2 executable's saying access was denied. I have it installed on my win7 laptop so I thought I would just copy the files. Once it got near the end it said I need administrative privileges for the exact same 2 files. I tried doing the "Take Ownership" but that didnt do anything. All my PC info is in my profile, and if you need any more info just ask.
Keith
PS. Added picture of me trying to extract 2 DIFFERENT executables from Winrar (files completely unrelated to the video game)
A:Saying I don't have admin privileges...
If you are running as admin, right click on the .exe and select run as admin. If that doesn't work, select troubleshoot compatibility.
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I need to install a software but when I click the file the UAC comes out and asks the usual questions. What I find weird is it does not give me the option to click YES. Only the NO button shows up. I checked and it seems that I am logged in as a local account. I tired everything but can't figure out to change the account type or log-in as admin. Only resort is to back up and do a restore PC but even the backup won;t let me go past the UAC.
Any help will be much appreciate.d
You cannot log in as an real admin. If UAC is not letting you past, there there is something wrong with the software or third party security software you may have installed. Where did you get this software and what is the name of it?
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On my personal computer my account is the Administrator but whenever I attempt to update windows or check for updates, it only says that "Some settings are managed by your system administrator", and it keeps me from changing the setting, I have
tried running the control panel as administrator but the same thing keeps appearing. Can someone please help me I am running on Windows 8.1.
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I already looked for an answer over at sourceforge to no avail When i right click on a file and select extract here under -zip's context menu I get an error saying I need elevated privileges I have already set zip file manager and zips CLI and set them both to use admin privilges in compatibility mode I think the error privileges? admin 7-zip is in shell and shellex context handlers of windows I am using an admin account I have looked through the registry values at and through all -zip entries I don't know what the error could be besides file and folder permissions does anyone know how to solve this or have any suggestions I think i might have to look through HKCR gt gt some more though I've only checked the HKCR gt 7-zip admin privileges? gt I'm not as familiar with that hive Things I've tried -Looked through of HKCU gt gt software gt gt Microsoft gt gt windows gt gt cur ver gt gt policies gt gt explorer -Looked through permissions and entries -zip reg entries -Uninstalled and reinstalled -Changed ownership of -zip and all child object to myself -Checked privilges of user account -
Here are the steps to modify ownership and permissions of folders and files:
1. Right-click the file or folder, click Properties, and then click the Security tab.
2. Click Advanced, and then click the Owner tab.
3. Click Edit, and then do one of the following:
· To change the owner to a user or group that is not listed, click Other users and groups and, inEnter the object name to select (examples), type the name of the user or group, and then click OK.
· To change the owner to a user or group that is listed, in the Change owner to box, click the new owner.
4. If you want to take ownership of the contents of the folder, select the Replace owner on sub containers and objects check box.
5. Click OK, and then click Yes when you receive the following message:
You do not have permission to read the contents of directory folder name. Do you want to replace the directory permissions with permissions granting you Full Control?
All permissions will be replaced if you click Yes.Note folder name is the name of the folder that you want to take ownership of.
6. Click OK, and then reapply the permissions and security settings that you want for the folder and its contents.
· An administrator can take ownership of any file on the computer.
· Assigning ownership of a file or a folder might require you to elevate your permissions using User Access Control.
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hi im trying to copy and paste a file but when i try and paste it i get the you need admin privileges but i am the admin, i have turned off the UAC and ive done the take ownership thing, in fact i think i downloaded something so ive always got the take ownership option in the folder options
but it still wont let me do it, is there a higher level of admin like super admin?
Open the security tab after right clicking on file or folder and choosing properties. Give your unique account permission by adding it. You have to actually type it and then check boxes too.
Then type.
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I got a free computer via a local "Help" disability program (yeah me!) However, things are very different on this system (Win 7) than my old one (I have background from DOS 3.1 - Win XP). I don't know if I'm looking at Win 7 issues or something the computer providers set up (will call when I see replies to this post).
Although I am, as best I can tell, the Admin., several folders are not accessible to me (such as C:\Documents and Settings or C:\Users\All Users).
Do you folks believe that there is an Admin. setting that I fail to see or is it possible that my computer providers made some sort of master Admin. control setting?
Thanks!
Rick
Welcome to the forum.
In Windows 7, Documents and Settings as well as several others in that folder are not real folders, they are Junctions that are there to allow legacy programs to interface to Windows 7's folder structure.
(Appdata is a hidden folder) to accomplish what Documents and Settings did in XP.
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I purchased a new Alienware computer 2 weeks ago and a couple days ago I noticed I couldn't access my Pictures folder. I also noticed I couldn't do any Admin tasks. I can't open task manager, Open any exe. files and when I right click on C drive I get Access is denied. I don't believe I've made any changes so not sure what went wrong. I could make changes and install programs prior.
Any help would be appreciative.
Thanks Dave
Since you bought it brand new and it is under warranty, suggest that you take it back for refund or exchange without delay.
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I think you might run your browswer as admin in order to be able to complete those online scans successfully. Have you tried that yet?
Have you run HiJack This as admin?
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A:32 bit programs require admin to run
Hi and welcome to TSF try creating a new account and see if it replicates there or not
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one day my grandmother was on the computer i don't know what she was trying to do but she went into the user accounts and family safety tab and revokes all of the admin privileges on the computer there aren't any more admin profiles how do i get the admin privileges back?
A:how do i get admin privileges back
Trying rebooting and hitting the F8 key. Go in to Safe Mode and there should be an administrator account you can use.
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Something has happened to our desktop. Kaspersky has been unable to update databases; sent them a message and have attempted all steps they suggested but am unable to run anything. Am not able to run or access anything as admin. There latest email stated to send them screen shots of everything (have attached them) Computer will not allow me to see users or change users. Not sure what's going on. Estimated to be having the problem for the past 2-3 weeks; coincidentally around the time Internet Explorer completely stopped working.
try safe mode to access admin with total permissions In safe mode you shpold be able to fix your problems
cmd in windows does not give full access permissions for some system access
make sure you have I.E. eleven installed down/load a new copy and install if necessary
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Hi
I seem to have lost admin rights/privileges on my account, even though it says i am an admin. I can't use windows update because of the following message. UAC is off.
I created another account and swapped admin privileges to that, and everything was ok, but as soon as i swap the privileges back to my original account, i get various 'this action requires admin rights' etc etc
I'm confused. I don't want to keep logging into another admin account just so i can use windows update.
I've tried this, but it said it couldn't fix all the problems. What can i try next folks?
Cheers
Just set up a new account. Give yourself privileges for the software in the first account. Make that the new account. The first account is corrupt
You can try this, too.
SFC /SCANNOW Command - System File Checker
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Is this possible? We have about 100 remote users who access our office network via VPN rather than RAS. All of these users are running either W2K or XP.
Our problem is that the internet settings on these laptops have been set (purposely) to automatically download updates from the Win Updates site. This bit works fine! But these updates cannot be installed as the users do not have administrator permissions on their local machine.
Is there a way of allowing these updates to install without giving the users full admin rights? (We REALLY don't want to give them these rights as suffice it to say that some of them are not as computer savvy as we would like.)
I have heard a little birdy say that there is a registry update which can bypass the above problem, but how and where?
Any advice on this will be greatly appreciated!
Thanks muchly.
See if that is any use to you
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The prompt for Admin during installs is actually a good thing (that is the UAC and you REALLY want it to prompt) BUT you can almost always use any log in the Administrators Group
use CP->User Accounts
save and close
runas /user:$whatever$you$just$created cmd
it will then create the %profile% for that new user
From then on, you can reply with $whatever$you$just$created and its password
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Nice work Microsoft! I just turned on my computer to find that my admin rights have been stripped from my user account. It's weird, I'm the only user of this computer and its a personal laptop.- Running Windows Vista on a 32bit HP DV5 Laptop- I can't access Task Manager from Ctrl+Alt+Del- Cannot enter Run -> Regedit as it returns a "Regediting has been disabled by your Administrator"Also there's this weird message below my Run command box:Any help?PS: UAC was turned off ages ago and similar problems went away. It's still turned off - no idea what's going on
Looks like a malware attack, this will Re-enable (http://www.raymond.cc/forum/general-forum/12672-re-enable-project-ideas-and-suggestions.html) but you need to AV scan to get rid of it.http://www.microsoft.com/Security_Essentials/
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WHY, PLEEZE tell me why, Win7 completely ignores the fact that I have Admin Privileges when I try to Stop Services, or do things that require Admin Priv's? I have the restrictions set at ZERO, or (DON'T BOTHER ME WITH MSGS).
A:How To REALLY Access Admin Privileges
You should have a look at the: Windows 7 Tutorials Quick Reference Index
Beginning from the letter "A" you'll find all related to Administrative tools & Administrator account, plus the related tutorials at bottom of each.
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I found a note about gaining permanent status as administrator which would save a lot of time since I'm the only one using this PC and it's a bore having to click on continue and continue every time I want to change, move or delete anything.
Can anyone remember this thread and what the title is?
I'd be eternally grateful.
docusk
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Hello! As the title says I can't do anything that requires admin privileges on my computer whether it's running a program as admin or deactivting my firewall/antivirus etc etc. Whenever I try to deactivate my firewall/antivirus nothing happens, and when I try to run a program as admin I end up with a window giving me an error message (I'll add a picture of it). So if anyone has got a clue on how to fix this then please help me, I would appreciate it so much!
EDIT: It's exactly the same error for every program that I try to run. The only thing that isn't the same is the file path shown, it shows the program that I'm trying to run.
A:Can't do anything that requires admin privileges!
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Hello.
I'm trying to inject an DLL with an old program, which worked fine before I re-installed. My old setup was Windows XP Pro Service Pack 2 + All updates.
My current setup is the same, Windows XP Pro with Service Pack 2 and all updates available through Windows Update. (except sp3)
However, it doesn't work. I think it's a privileges issue. My user account is "Administrator" and a part of the "Administrators" group. I've also enabled the "Debug Programs" privileges on my account, even though it's already on by default for administrators.
It fails on this function:
It just returns 0. Even though the HWND i'm passing to it is correct (checked, 100 times.)
any suggestions?
Hello and welcome to the forum,
What DLL and what is the program your trying to inject the DLL to?
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I left on vacation over the past weekend. Upon my arrival home, I went to my computer to check my mail. I noticed a second account but thought nothing of it on the log-in screen. Later, as I am trying to update my programs such as iTunes, I come to find out that my administrator privileges are gone. My roommate has confessed to changing adding an administrator account and demoting my account. However, the password he set was from a random password generator and is only recorded in a text file on the desktop of the admin account. How do I regain my administrative privileges on the computer and delete the other account?
I have an HP Pavillion p7-1207c.
I have tried restoring the system from a backup, but that requires an admin's permission.
A:How do I regain Admin privileges?
Not a smart guy... that roommate of yours!
User Account Password - Change from WinRE
In step 7 do:
Code:
Now give the name_of_admin_account a new password so you can logon. Now you can give the other acount admin priviliges. You can delete the name_of_admin_account when logged on as admin account. Step 8 to 13 aren't needed of course
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when i click on soemthing that needs admin privileges it does not ask me for my password to confirm it how do i change things i have windows 8.1
Some areas the user can NOT make changes.
What changes are you trying to make?
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Hallo,
I wrote a Script that uninstalls an application, move some files and install an Application.
The Script is working if I start it as Admin (right click - run as Admin ...).
Everything works fine.
But I want to have it working without the "run as".
The script is only used in a separated Test system,
so there is no problem if the Admin user name and password is in the script.
(also link wouldn't work, should also work if it moves to another station within the test domain)
Is there a way to manage that?
Batch command runas with a standard trick
it is NOT going to work, because the password should be entered manually.
If you do not mind clicking Yes in UAC window you can use Elevate.exe
With it you won't need writing password anywhere
"C:\yourFOLDER\elevate.exe" "C:\yourScriptFOLDER\yourScript.bat"
would be enough to start script with admin privileges (still need to click YES on UAC window).
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I am signed in as the Administrator of my computer, however, the system will not allow me to install my antivirus. It gives me an error message saying that I need admin. privileges to install.
I did have some viruses but fixed them, now I can't install.
Thanks!!!
Try tapping F8 as you push power button until you get safe mode option. Go into safe mode and try install.
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As the title says, i'm having a difficulties burning a CD (computer has a Combo DVD/CD-RW drive) in the facullty network.
The problem is (at least i think so) becouse they deleted aspi drivers from Windows directory.
Is there any possible way to burn a CD, and what is it?
Regards,
[email protected]@d0x
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Hi all,
I have a loptop with windows xp, but my user is having limited privileges.
Is it possible to give admin privileges to a particular command or a set of commands (say for example i wanted to set the IP address of the machine from the limited user) from the admin login.
Chandu
Im sure if u assign the laptop an IP address another account would use that.
Unsure and not willing to test it, but you could try!
Aslong as you know the admin stuff...we cant help with passwords :)
i dont think you can change the admin/limited rights..if they need to install programs..i would set as admin, what damage could they do :P lol
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I ve suddenly Lost permissions... privileges Admin and been denied quot permission quot or access privileges to install or even update programs on my computer I have tried going back Lost Admin privileges and permissions... to several different restore points but none of them have helped I have Windows XP Pro SP on this computer and only one quot user quot account which is of course an Administrator account The quot permissions quot are check with FULL CONTROL with all boxes checked I would greatly appreciate all the help I can get because I ve tried everything I can think of to resolve this problem without success Actually I m afraid I just keep making matters even Lost Admin privileges and permissions... worse because now my computer runs awfully slow and programs stall or just shut down suddenly I was going to just give up and re-install windows hoping that would correct my problems but a friend told me to try seeing if anyone here could help me out first Thanks in advance for your help GJ nbsp
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Ever since my first attempt to convert Win7 to 10, I can't write or delete anything in My Documents, getting message must be administrator. (My personal login is as administrator.) This even happened in Win 7 when I reverted back for a while. Error message asks if I want to save in My Documents instead, and then allows it (outside of my desired sub-directory). However, cannot delete files.
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Beginner level
After a failed Windows Update some months ago, I was unable to get any further updates. The error message 80070005 indicated I did not have 'privileges' to do so. I installed Hotfix, although not sure what this actually achieved. After Flash crashed later on, I tried to install the newest version, but again, I do not have Admin Privileges to do so. Tried with and without Norton 360 running, with and without Windows Defender running.
Looked at User Accounts. Tried with and without User Account Control turned off.
Gave the PC several full scans, no problems detected.
Looked at some online tips, but as a beginner, don't want to go anywhere near tinkering with the Registry.
help appreciated
Welcome
In addition, if you can try to create a new administrator account, for daily use.
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I installed Win XP Pro and created Power User account for wife and child. Now programs like Microsoft Picture It say they need admin privileges to run. Some childrens games also want admin privileges. I created these accounts so that wife and child would NOT be able to modify system files. How do I fix this without giving them admin privileges.
Thanks
Don
A:WIN XP PRO: Some Programs Requires Admin Privileges to run
Basics....
http://www.microsoft.com/windowsxp/pro/using/howto/security/accesscontrol.asp
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I am the admin and sole user. I tried to move a system file and the dialogue stated you do not have elevated privileges. So, my admin priv is not elevated.
A:trying to get full elevated admin privileges
Hello Mark, and welcome to Eight Forums.
What system file are you trying to move?
If you like, you could enable the built-in "elevated" Administrator account, then sign in to it to have full elevated rights when needed. Do note, that Store apps will not work in elevated accounts.
Built-in Administrator Account - Enable or Disable in Windows 8
Hope this helps,
Shawn
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I'm sure there must be a simple way to do this, but I don't know how. At the hotel where I work I setup the lobby computer. There is my admin acct and then the hotel guests acct, the latter is a windows "guest" acct. I would like to go into that acct and delete some things, but I can't figure out how to get admin privileges within that acct to do so.
Thanks.
hcour,
First, on the admin account, enable (temporarily or otherwise) UAC: User Account Control - UAC - Change Notification Settings
Then go into the limited account and change whatever you would like, with your admin user name and password handy.
Hope this helps
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I've been running Vista Ultimate and Photoshop CS for more than a year and suddenly today when I try to open PS it says that "Current user account does not the privileges to perform product activation..." and refuces to open. If I go to the PS exe and check the box for Run as Admin it runs (altho I have to click the UAC warning when using this setting). Any ideas as to what is happening? (No major software or hardware changes recently.)
A:Photoshop CS suddenly needs admin privileges
It appears to be covered here.
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Is it possible to launch an application from start->run dialog box with administrator privileges?
A:Launching an app from start->run with admin privileges?
Click start, click all programs, click accessories, Right click "command prompt" and choose "Run as Administrator" now run your app.
or just go to the app in all programs, right click and choose "Run as Administrator".
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A:Running computer as someone without Admin privileges.
Not necessarily. A standard user account can be infected by some malware. But yes, it is a preventive measure and should be used.Read this : http://www.bleepingcomputer.com/tutorials/create-new-user-account-in-windows-vista-7/I suggest, that you use Sandboxie and run your browser inside it. http://www.sandboxie.com/Sandboxie runs your programs (like your browser) in a totally isolated space, so even if a malicious site installs something, all you have to is clean the contents of Sandboxie.Some antivirus like avast! also have an inbuilt sandbox which run suspicious programs inside it automatically, preventing them to make actual changes to your computer.
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Hi everyone,
I need some help regarding removing restrictions on a secondary drive, drive D: on xp. I have admin privileges on the account i'm using. I was trying to restrict drive D for another user.. and instead it's my own account that got restricted!
This is what i've done,
1) Went to tools>folder options>view>unchecked simple file sharing
2)Then right clicked on drive D: > security tab and removed access from drive for that particular user..
now.. it's my own account that's restricted..
i created another account.. admin.. to see if the drive can be accessed from another one, and yes it can.. it's just mine that is restricted :/
I tried to change all the settings to full control on my account.. i changed the ownership too.. yet it's not working :s I'm lost and not tech savvy at all
would formatting remove the restrictions on that drive?
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When users with admin privileges have ownership of files and folders, do those files and folders remain, or are they deleted?
This question arises from having tried to copy my primary admin profile to that of a new (backup) admin user. During that tedious and unsuccessful process, I had to change ownership and privileges of a number of folders and files, and now some of my programs are having trouble finding needed files. So rather than wading through everything and changing the settings back, I'd prefer to delete the new admin user -- as long as I won't lose the files.
Does that even make sense? (It's way past my bedtime!)
Make copys of all the files you want to keep or use an admin account and pull the files onto the account you wish to keep then delete the old one. As long as you have a copy that you have privileges to on the account you are going to keep you should be fine, just make sure to keep a copy of all the files that you can get into.
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A:How to gain back Admin Privileges?
Are there other user accounts then?
There has got to be a Admin account.
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I need admin rights on my windows 7 computer because I cant download or delete anything on my pc. It is used for school so I NEED the admin rights. Is there any way without entering a Admin Password?
Thanks
No as that could be a possible confidential breach.
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So I have this problem, that I can't run anything what needs to get admin privileges, like installing stuff, changing windows settings etc. The consent window doesn't open up. There are consent.exe processes in Task Manager, I need to close em by ending processes because if I don't, they'll just sit there doing nothing.
A:[SOLVED] Can't run any programs which need admin privileges.
Push your UAC Control up and reboot - See if that invokes the prompt?
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http://windowsxp.mvps.org/exefile.htm
joan
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Hi Team,
i want to install a application without admin privileges, please provide example batch file or command for the same.
NTRao
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Hi,
i am a lil bit confused here. the program name is xfire, i want to start it when windows start. problem is, it needs admin rights to start, so if i put it on when windows start, the admin box comes in and stalls everything else from loading.
is it possible to make it run without it needing admin rights? I still want the same security level, just exclude this program?
A:Make a program not require admin rights?
Quote: Originally Posted by Cee
Hi,
i am a lil bit confused here. the program name is xfire, i want to start it when windows start. problem is, it needs admin rights to start, so if i put it on when windows start, the admin box comes in and stalls everything else from loading.
is it possible to make it run without it needing admin rights? I still want the same security level, just exclude this program?
Right click the executable and check run as admin. You cant "exempt" one application, but you can elevate one.
Ken
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Hi guys,
so my friend came to me that he had some problems with his notebook. I thought I'd solve these in a matter of minutes as I am pretty experienced.
But I see it's a bit more complicated...
So here's the issue.
The system isn't recognizing usb devices when I plug them in (mouse, external hdd, phone) but it recognized my usb flashdrive.. so I looked into the drivers.
Here are some screens:
http://i57.tinypic.com/33cnpmo.jpg
http://i57.tinypic.com/htsqb7.jpg
Any ideas on how to make some progress?
Thanks
A:[SOLVED] driver problems and admin privileges
Hi there .o/
I guess it would help if the error message clearly stated access to what is denied :(
Did you try installing those drivers from the "administrator" account ? Disabling UAC (and rebooting) just in case ?
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I have encountered a curious problem at work. All clients use limited users and in this case there's a Windows 7 on x64 on which I don't have privileged access at all. The normal behaviour, as far as I know, is that when I try to access something that needs administrator privileges, a window shows up and asks me for a privileged user's password. There are two users on the machine (a user called "Admin", the other one being the limited user) and I expect this behaviour (the password windows popping up) when trying access something that needs privileges - this is what happens at home, for instance, as I don't use a privileged user for security reasons.
Any suggestions on how to make that window pop up?
Thanks
Are you the admin? Did you set up the limited user account? Just want to make sure you didn't lock yourself out.
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Guys I've [SOLVED] Privileges to Full Set Admin User already experienced [SOLVED] Set User to Full Admin Privileges issues of not being able to complete easy installs due to quot Permissions Denied quot I am an Admin on my own personal PC and I'm not sure what I need to do make a permanent change for my personal user profile to not incur any more policy restrictions Below is the simple task I attempted to schedule when I last created a Permissions Error Run the following command from a command prompt once to disable hibernation powercfg -h off Open Task Scheduler and create a new simple task give it a name Sleep Set the Trigger to Daily Set the Start time to the time you want the computer to sleep set Recur every day Set Action to Start a program Set the Program to C Windows System rundll exe Set the Argument to powrprof dll SetSuspendState On the Finish page check the box to Open the Properties dialog for this task when I click Finish On the General page under Security options select Run whether user is logged on or not and check Run with highest privileges
A:[SOLVED] Set User to Full Admin Privileges
I see plenty of views and no reply--hmmm. I repeat this is my personal PC and I am the owner and admin. I think certain permissions may be blocked by my antivirus or some other process, or just a protection feature I didn't turn off when i set up my laptop. I need guidance on what components of Win7 would hinder my ability. This is not an attempt to hack past policy, and if i was a limited user on my home pc then obviously the options i would need to enable wouldn't be available to modify (just in case that was a reason for a lack of response). Once again, please provide guidance on a possible option i would need to check into first. Thanks.
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I have an admin acct that doesn't seem to have privileges. One issue is that I'm unable to create a user acct (specified acct name not valid, cannot contain the following characters: |[]”:;|<>+=,?*)
The new user name contains no such characters.
So I enabled the hidden admin acct, which seems to have privileges, but gets the same error when trying to create a new acct.
various virus, malware and rootkit detection utilities don't find anything. Outside of the admin issues and account creation, the system runs fine.
This system is a Dell XPS 410, upgraded to win 7 Pro x64 SP1 from XP (before I obtained it).
Any ideas appreciated.
Thanks!
A:Admin has no privileges, cannot create user account
I'm checking into profile issues...System Properties\Advanced|User Profile settings shows the users in the below image.
All seems well except for the Account Unknown. I guess #1 is the hidden admin account, #'s 2 & 3 are the named user accts.
There was an account named updatususer. Research shows that this is an nvidea update service account. I removed it from the admin account (still can't create a new user).
in a cmd window, 'net user' returns only users #2 & #3. User #3 is the local admin account without privileges.
Any ideas as to what the Account Unknown user could be (if it's even pertinent to the issue)? I thought it might be the guest account, but it's not turned on.
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running windows 8.1
scanned with malwarebytes, and removed infections from I believe uwade.
now... when I try to system restore on, get message, that I do not have administrator privileges, same when I try to turn on superantispyware on even try to uninstall it..?
cannot find gpedit.msc, probably because I am running home edition?
so how do I get system restore back.???
A:How do I get system restore back, no admin privileges?? Help
At the end, be sure a checkmark is placed next to the following:
Launch Malwarebytes Anti-MalwareA 14 day trial of the Premium features is pre-selected. You may deselect this if you wish, and it will not diminish the scanning and removal capabilities of the program.
Click Finish.On the Dashboard, click the 'Update Now >>' linkAfter the update completes, click the 'Scan Now >>' button.
Or, on the Dashboard, click the Scan Now >> button.If an update is available, click the Update Now button.
A Threat Scan will begin.When the scan is complete, if there have been detections, click Apply Actions to allow MBAM to clean what was detected.In most cases, a restart will be required.Wait for the prompt to restart the computer to appear, then click on Yes.If you already have MBAM 2.0 installed:On the Dashboard, click the 'Update Now >>' linkAfter the update completes, click the 'Scan Now >>' button.
Or, on the Dashboard, click the Scan Now >> button.If an update is available, click the Update Now button.
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Hello,
I am currently running W7 Ultimate 64 Bit with Norton 2011 and Comodo 5.????. I noticed I didn't have a site advisor on FF. So I installed McAfee. It seems to react after a file is downloaded and everything even Windows Gadgets are unsafe and must be blocked. I downloaded Norton Safe Web Lite to replace it. It downloaded in priviledged account (standard). It won't let me run or delete it saying I don't have permission or privilege to do so. If anyone has any ideas I'd appreciate it. Thanks in advance for any assistance.
glennc
A:Can't Access file for deletion with Admin Privileges
Decide on which antivirus program you want to use... You look like you have 3 installed.. That is 2 too many ... I would also uninstall Norton Safe Web Lite... If you are still having problems uninstalling a file, boot into safe mode and delete the file...
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I don't use Windows 7 but a buddy of mine does. I made a program in VB.NET and I install it to the program files folder. It goes to access files from there (because I'm not advanced enough to do it internally), and he's getting an error that he's got insufficient rights to access the file(s). I'm told it's because he doesn't have administration rights to the folder.
I remember a while ago someone gave me a program that gave me instant admin rights to any folder in Vista, I was wondering if there was something like that for Windows 7? And if not, how would he go about changing it so that he's admin?
A:Admin privileges to program files in Windows 7?
well for one he has to be on an Administrator account
If, he is then you will have to take ownership of the folder
Quote:
Right-click the folder | select "properties" | go to the "security" tab | click "advanced" | "owner" tab | "edit" | select his account from the list | "check" the check box bellow ("replace owner on subcontainers and objects") Also make sure that he has full permission...
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Hi. I was experimenting one day and I accidentally made my guest account an administrator. Is there a way to undo this? I just don't want to make another standard account because I feel like it's eating much space in my Hard Drive and files and programs are doubling. Somebody help!
A:Guest Account with Admin Privileges. How do I undo?
hi and welcome toTSF go start and at the top right you will have a little picture click on it that will take you to user accounts if your logged in on your account as admin you can change the account type for your guest account
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At the first time (I didnt the real cause above), I did format of my win8.
After that, the second time I install HoldemManager2 and ( ) I lost my admin privileges again.
Any clue before I start format again ?
In safe mode I can't create users...
Also in safe mode I tried uninstall HM2... win8 says: "contact admin"
I disable the postgress service, but even this is not working...
Try adding "Take Ownership" to the Shell:
See if you can elevate your Privileges with that. It may be the permissions for the whole folder where you have these files stored.
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Hello,
I've just cleaned up a massive malware infection on my grandson's computer (HP Pavilion notebook) and upgraded it to Win 10 from its native Win 8. His account is a standard user vs admin. Everything's working fine. EXCEPT, he plays an online game which requires an admin password to boot. What I'm trying to do is create access to the program without having to log him in every time. The command I'm trying to implement is:
Of course I swapped out the real computer name and user name, and I've tried working with the existing shortcut pinned to the taskbar, so I know I've got the correct file path. I've also tried creating a brand new shortcut, but I can't get the program to boot. Perhaps Win 10 doesn't allow a runas command for a standard user.
Is there another way - that isn't too complicated - to do this?
A:shortcut w/admin privileges for standard user
Hello 3point1,
You would need to use the credentials of the built-in Administrator account instead for that command to work.
Elevated Program Shortcut - Create for Standard User - Windows 7 Help Forums | {"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": 0.21842549741268158, "perplexity": 3151.5041882054143}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257645538.8/warc/CC-MAIN-20180318052202-20180318072202-00300.warc.gz"} |
http://mathhelpforum.com/calculus/153112-derivatives.html | # Math Help - Derivatives
1. ## Derivatives
Ley $y=g(h(x))$ where $h(x)=x^2/(x+2)$. if $g'(9/5)=-2$,find $dy/dx$ where x=3
2. $\dfrac{dy}{dx}=g'(h(x)) \cdot h'(x)$ | {"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": 5, "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": 0.9884717464447021, "perplexity": 12959.74665725623}, "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-2014-10/segments/1394010359804/warc/CC-MAIN-20140305090559-00087-ip-10-183-142-35.ec2.internal.warc.gz"} |
https://sublinear.info/index.php?title=Open_Problems:79&oldid=1038&diff=prev | # Difference between revisions of "Open Problems:79"
Suggested by Joshua Brody Banff 2017 https://sublinear.info/79
Cryptogenography is concerned with the following question. "How to share a secret without revealing the secret owner?" Please see Brody et al. [BrodyJSW-14].
In this problem, there are $k$ players and an eavesdropper. Input is a random bit $X \in \{0,1\}$, also called "the secret." The secret owner $J$ is chosen uniformly at random from $[k]$. Players have private randomness and they can communicate publicly on a shared blackboard visible to everyone. Players are said to win if
• everyone learns the secret, and
• eavesdropper does not guess the secret owner correctly.
We are interested in maximizing the probability that players win (maximum success probability).
For $k=2$, the following trivial protocol has success probability $0.25$. Just output $1$. It can be shown easily that maximum success probability is at most $0.5$. The bounds can be improved to $0.3384 \le$ maximum success probability $\le 0.361$. Here is a protocol that achieves success probability $1/3$.
First round: If Alice has the secret,
• with probability $2/3$ she asks Bob to speak second
• with probability $1/3$ she speaks second.
Else (vice-versa)
• with probability $2/3$ she speaks second
• with probability $1/3$ she asks Bob to speak second.
Second round: If the speaker has the secret, announce it, else announce a random bit.
For large $k$, the following bounds can be shown: $0.5644 \le$ maximum success probability $\le 0.75$.
Can we improve these bounds? | {"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": 0.8485859632492065, "perplexity": 1288.49338720585}, "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-2022-21/segments/1652662509990.19/warc/CC-MAIN-20220516041337-20220516071337-00647.warc.gz"} |
http://finalfantasy.wikia.com/wiki/Horology | ## FANDOM
35,380 Pages
Horology (時間攻撃, Jikan Kōgeki?) is a technick in Final Fantasy XII that uses the game clock's minute to deal damage on target's within a radius around the selected target.
This is done according to the formula:
$Damage = L/2 \times X^2$
In the Zodiac versions it is:
$Damage = L \times X^2$
In which $L$ is the user's level and $X$ is the second digit in the game clock's minute. Due to the nature of the formula, damage dealt from using Horology caps at 4,009 HP (8,019 HP in Zodiac versions) ($99/2 \times 9^2$). The attack rarely misses and can be used multiple times within the minute. If used on multiple enemies, it will always hit one of them, even if blinded.
Horology's damage is actually determined at the moment the damage is inflicted. Even if the caster starts readying it during XX:47:55 and the damage is inflicted during XX:48:02, its damage is calculated during the damage. So, the damage calculation is:
$L/2 \times 8^2$ instead of $L/2 \times 7^2$
Exploiting Horology is easy with by pausing during its charge time via the party menu. Once the second digit of minutes reaches nine, Horology's potency will be at its peak. However, using it consecutively can be tedious.
In the Zodiac versions, this technick can be used by three job classes: Machinist, Time Battlemage and Foebreaker, although Foebreaker must acquire the Esper Belias license first.
In the Zodiac versions, Horology can be bought from shops after the party returns from the Leviathan. In the original, it is available slightly earlier, from the technick shop in Bhujerba. It is also a treasure in the Trial Mode Stage 22 with Diamond Armlet.
## EtymologyEdit
Horology is the art or science of measuring time. Clocks, watches, clockwork, sundials, clepsydras, timers, time recorders and marine chronometers are all examples of instruments used to measure time. | {"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": 0.29262349009513855, "perplexity": 5929.072745288469}, "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-2019-04/segments/1547584431529.98/warc/CC-MAIN-20190123234228-20190124020228-00576.warc.gz"} |
https://deap.readthedocs.io/en/latest/examples/gp_parity.html | # Even-Parity Problem¶
Parity is one of the classical GP problems. The goal is to find a program that produces the value of the Boolean even parity given n independent Boolean inputs. Usually, 6 Boolean inputs are used (Parity-6), and the goal is to match the good parity bit value for each of the $$2^6 = 64$$ possible entries. The problem can be made harder by increasing the number of inputs (in the DEAP implementation, this number can easily be tuned, as it is fixed by a constant named PARITY_FANIN_M).
## Primitives set used¶
Parity uses standard Boolean operators as primitives, available in the Python operator module :
pset = gp.PrimitiveSet("MAIN", PARITY_FANIN_M, "IN")
In addition to the n inputs, we add two constant terminals, one at 0, one at 1.
Note
As Python is a dynamic typed language, you can mix Boolean operators and integers without any issue.
## Evaluation function¶
In this implementation, the fitness of a Parity individual is simply the number of successful cases. Thus, the fitness is maximized, and the maximum value is 64 in the case of a 6 inputs problems.
def evalParity(individual):
func = toolbox.compile(expr=individual)
return sum(func(*in_) == out for in_, out in zip(inputs, outputs)),
inputs and outputs are two pre-generated lists, to speedup the evaluation, mapping a given input vector to the good output bit. The Python sum() function works on booleans (false is interpreted as 0 and true as 1), so the evaluation function boils down to sum the number of successful tests : the higher this sum, the better the individual.
## Conclusion¶
The other parts of the program are mostly the same as the Symbolic Regression algorithm.
The complete examples/gp/parity.
## Reference¶
John R. Koza, “Genetic Programming II: Automatic Discovery of Reusable Programs”, MIT Press, 1994, pages 157-199. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4808278977870941, "perplexity": 1548.6883093810816}, "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/1593655893487.8/warc/CC-MAIN-20200707142557-20200707172557-00239.warc.gz"} |
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# Bilayer of polyelectrolyte films for spontaneous power generation in air up to an integrated 1,000 V output
## Abstract
Environmentally adaptive power generation is attractive for the development of next-generation energy sources. Here we develop a heterogeneous moisture-enabled electric generator (HMEG) based on a bilayer of polyelectrolyte films. Through the spontaneous adsorption of water molecules in air and induced diffusion of oppositely charged ions, one single HMEG unit can produce a high voltage of ~0.95 V at low (25%) relative humidity (RH), and even jump to 1.38 V at 85% RH. A sequentially aligned stacking strategy is created for large-scale integration of HMEG units, to offer a voltage of more than 1,000 V under ambient conditions (25% RH, 25 °C). Using origami assembly, a small section of folded HMEGs renders an output of up to 43 V cm−3. Such integration devices supply sufficient power to illuminate a lamp bulb of 10 W, to drive a dynamic electronic ink screen and to control the gate voltage for a self-powered field effect transistor.
## Access options
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## Data availability
The data that support the findings of this paper are available from the corresponding authors upon reasonable request.
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## Acknowledgements
This work was supported by the National Key R&D Program of China (no. 2017YFB1104300), the National Science Foundation of China (nos. 22035005, 52022051, 22075165, 52073159 and 52090030), Tsinghua University Initiative Scientific Research Program (no. 2019Z08QCX08), NSFC-STINT (no. 21911530143), the State Key Laboratory of Tribology (no. SKLT2021B03) and Tsinghua-Foshan Innovation Special Fund (no. 2018THFS0412). This work is also supported by grant no. 2019GQG1025 from the Institute for Guo Qiang, Tsinghua University.
## Author information
Authors
### Contributions
L.Q., H.C. and H.W. designed the experiments. H.W., H.C. and T.H. performed the experiments. Y.H. conducted computational studies. H.W., Y.S., D.X., P.Y. and Y.Z. designed and characterized the self-powered FET. H.C. and C.L. gave advice on experiments. L.Q. and H.C. supervised the entire project. All authors discussed the results and reviewed the manuscript.
### Corresponding authors
Correspondence to Huhu Cheng or Liangti Qu.
## Ethics declarations
### Competing interests
The authors declare no competing interests.
Peer review information Nature Nanotechnology thanks Guihua Yu and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
## Supplementary information
### Supplementary Information
Supplementary Figs. 1–33, Discussion and Tables 1–6.
### Supplementary Video 1
Integration of HMEG units by the sequentially aligned stacking method.
## Rights and permissions
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Wang, H., Sun, Y., He, T. et al. Bilayer of polyelectrolyte films for spontaneous power generation in air up to an integrated 1,000 V output. Nat. Nanotechnol. 16, 811–819 (2021). https://doi.org/10.1038/s41565-021-00903-6 | {"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": 0.8550807237625122, "perplexity": 29823.13319475984}, "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-2021-39/segments/1631780057584.91/warc/CC-MAIN-20210924231621-20210925021621-00250.warc.gz"} |
http://mathoverflow.net/questions/102628/when-is-a-quantum-affine-space-mathbban-calabi-yau?sort=votes | # When is a quantum affine space $\mathbb{A}^{n}$ Calabi-Yau?
I would like to ask a simple question. Let $A=\mathbb{C}\langle x_{1},\dots,x_{n} \rangle/I$, where $I$ is the two-sided ideal generated by $x_{i}x_{j}=a_{ij}x_{j}x_{i}$ for $1\le i,j\le n$. We say a $\mathbb{C}$-algebra $B$ is n Calabi-Yau if the category of left $B$-modules is a Calabi-Yau n category, i.e. $Ext_{B}^{i}(M,N)\cong Ext_{B}^{i-n}(N,M)^{*}$ for any left $B$-modules and $i \in \mathbb{Z}$. I am not sure if this is equivalent to Ginzburg's definition of CY algebra, but the above definition seems simpler and practical.
My questions is, when is the above algebra $A$ a $n$ Calabi-Yau? More precisely, what condition on $a_{ij}$s do we need, other than $a_{ij}=a_{ji}^{-1}$?
Also, if we consider bi-module category (with similar definition), are things much harder?
-
Are $r_{ij}$ the same as $a_{ij}$ in your question? – Vladimir Dotsenko Jul 19 '12 at 9:45
Thanks, Vladimir. I corrected the typo. – Muon Jul 19 '12 at 10:18
Note as in my notes mentioned in B. Bischof's response, there is a nontrivial condition required to be Calabi-Yau instead of merely twisted Calabi-Yau.
Finite global dimension would follow from your condition since in particular it would imply that any $\operatorname{Ext}$ vanishes above degree $n$.
Your definition is, however, missing a finiteness condition. For instance, in the simplest case where $B$ is the polynomial algebra and $B=M=N$, then $\operatorname{Ext}^0(M,N)=B$ but $\operatorname{Ext}^n(M,N)=0$.
You can fix this problem by requiring that $M$ and $N$ be finite-dimensional. However, the conditions are then not equivalent, but rather Ginzburg's definition implies (but is not implied by) your condition. For example, if $B$ is a Weyl algebra (which is Calabi-Yau) there are no finite-dimensional modules at all.
Here is a proof that Ginzburg's condition implies yours: Suppose B is $n$-CY and $M$ and $N$ are finite-dimensional modules. Let $P^\bullet$ be a projective bimodule resolution of $A$. Thus $P^{\bullet} \otimes_A M$ is an $A$-module resolution of $M$ and similarly for $N$. Then
$\operatorname{Ext}^i(M,N)^* \cong \operatorname{H}^i(\operatorname{Hom}_{A}(P^{\bullet} \otimes_A M, N))^* \cong \operatorname{H}^i(\operatorname{Hom}_{A^e}(P^{\bullet}, A) \otimes_{A^e} (M^* \otimes N))^*$,
and now using the CY condition, we get
$\cong \operatorname{H}^i(P^{n-\bullet} \otimes_{A^e} (M^* \otimes N))^* \cong \operatorname{H}^i(\operatorname{Hom}_{A}(P^{n-\bullet} \otimes_A N, M)) \cong \operatorname{Ext}^{n-i}(N,M).$
In the proper setting where $B$ is replaced by a dg algebra which has finite-dimensional homology, then the converse does hold provided you allow $M$ and $N$ to be modules with finite-dimensional homology. Note that it is important here that we work in the dg setting, since otherwise we again have $\operatorname{Ext}^n(B,B)=0$ for all $n \geq 1$.
-
Thanks for your answer, Travas. You are right, the finite global dimension follows from the definition. I still don't quite understand your exercise: Is it obvious that the condition implies n CYness? – Muon Jul 20 '12 at 20:39
Not immediately obvious to me, but one can prove that it implies n-CY by noticing that the condition is exactly what is needed to have a cyclically supersymmetric superpotential as in the sense of, e.g., Bocklandt-Schedler-Wemyss, and then one can see that the corresponding complex is indeed a projective bimodule resolution of your algebra A, just as in the case where all the $a_{ij}$ are one. – travis schedler Jul 21 '12 at 8:15
The answer to the question "is the functions on quantum affine space a Calabi-Yau algebra?" is yes.
It is presented here (in particular 5.2) in Travis Schedler's notes from MSRI.
However, if this coincides with your alternate definition of CY I do not know. The definition of CY and twisted CY as used in this are 3.27. If I remember correctly the discussion, this is supposed to coincide in some sense with the categorical definition. In particular, by making the Ext condition with respect to Hochschild Homology, but also adding a resolution length condition.
-
Thanks! This is exactly what I am looking for, as long as the definitions coincide. I wonder whether this is easy to prove or not. You are right: I may want to impose "smoothness", or finiteness of global dimension. I think that my example is OK. – Muon Jul 19 '12 at 10:29 | {"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": 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": 0.9866555333137512, "perplexity": 293.9502583731386}, "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/1427131296974.26/warc/CC-MAIN-20150323172136-00263-ip-10-168-14-71.ec2.internal.warc.gz"} |
http://cloud.originlab.com/doc/LabTalk/ref/Options_for_Error_Bars | 3.3.2.55.7 Options for Error Bars
-o
Syntax: set name -o YDataset
Plot the values in the name dataset as Y error bars for the plotted Ydataset. name must be a plotted dataset. For example, if column B and column C are displayed as line data plots in the active graph window, the following example displays column C as Y error bars for column B.
range err = [Book1]Sheet1!col(C);
range line = [Book1]Sheet1!col(B);
set err -o line;
-om
Syntax: set -om YDataset
Plot the values in the name dataset as Y (minus) error bars for the plotted YDataset. name must be a plotted dataset. For example, if column B and column C are displayed as line data plots in the active graph window, the range rc = [Book1]Sheet1!C; range rb = [Book1]Sheet1!B; set rc -om rb; command displays column C as Y (minus) error bars for column B.
-op
Syntax: set name -op YDataset
Plot the values in the name dataset as Y (plus) error bars for the plotted YDataset. name must be a plotted dataset. For example, if column B and column C are displayed as line data plots in the active graph window, the range rc = [Book1]Sheet1!C; range rb = [Book1]Sheet1!B; set rc -op rb; command displays column C as Y (plus) error bars for column B.
-or
Syntax: set name -or YDataset
Plot the values in the name dataset as Y error bars (relative) for the plotted YDataset. name must be a plotted dataset. For example, if column B and column C are displayed as line data plots in the active graph window, the range rc = [Book1]Sheet1!C; range rb = [Book1]Sheet1!B; set rc -or rb; command displays column C as Y (plus) error bars for column B.
-ox
Syntax: set name -ox YDataset
Plot the values in the name dataset as X error bars for the plotted YDataset. name must be a plotted dataset. For example, if column B and column C are displayed as line data plots in the active graph window, the range rc = [Book1]Sheet1!C; range rb = [Book1]Sheet1!B; set rc -ox rb; command displays column C as X error bars for column B.
-oxm
Syntax: set name -oxm YDataset
Plot the values in the name dataset as X (minus) error bars for the plotted YDataset. name must be a plotted dataset. For example, if column B and column C are displayed as line data plots in the active graph window, the range rc = [Book1]Sheet1!C; range rb = [Book1]Sheet1!B; set rc -oxm rb; command displays column C as X minus error bars for column B.
-oxp
Syntax: set name -oxp YDataset
Plot the values in the name dataset as X plus (error) bars for the plotted YDataset. name must be a plotted dataset. For example, if column B and column C are displayed as line data plots in the active graph window, the range rc = [Book1]Sheet1!C; range rb = [Book1]Sheet1!B; set rc -oxp rb; command displays column C as X plus error bars for column B. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 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": 0.37129050493240356, "perplexity": 7312.526857532106}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585370503664.38/warc/CC-MAIN-20200331181930-20200331211930-00422.warc.gz"} |
http://math.stackexchange.com/questions/222671/can-the-convergence-of-sequence-lead-to-the-convergence-of-function-as-x-to-in | # Can the convergence of sequence lead to the convergence of function as $x\to+\infty$
When read Zorich's book Mathematical Analysis Vol I, I figure out a question concerning the Theorem 5, Page 133. That is:
Assuming function $f:(0,+\infty)\to\mathbb{R}, \text{ with } \lim\limits_{\mathbb{N}\ni n\to\infty} f(n)=A\in\mathbb{R}\cup\{+\infty,-\infty\},$ where $\mathbb{N}$ is the set of all positive integers. Is it true that $\lim_{x\to+\infty} f(x)=A$?
I guess that it may be true. But I am not so sure. Maybe it is just a corollary of Theorem 5, page 133 of Zorich's Book (see above). Can anyone help me? If it is false, give your counterexample, and if it is true, prove it. Thanks a lot!
-
No. Consider $f(x) = \sin \pi x$.
The answer is negative, and the example by Hagen von Eitzen suffices. If you do not care about regularity, you can also consider the function $$f(x)= \begin{cases} 0 &\text{if x is rational} \\ 1 &\text{if x is irrational,} \end{cases}$$ for which $f(n)=0$ for all $n \in \mathbb{N}$ but $\lim_{x \to +\infty} f(x)$ does not exist for obvious reasons.
To understand the situation heuristically, you can recall that $\lim_{x \to +\infty} f(x)=\ell$ if and only if, for any sequence $x_n \to +\infty$ there results $f(x_n) \to \ell$ as $n \to +\infty$. It is reasonable that the behavior of $f$ along one sequence like $x_n=n$ cannot describe the richness of the behavior along any diverging sequence. You can approach $+\infty$ in infinitely many ways, and you must consider them all together, if you want to compute the limit. | {"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": 0.9416650533676147, "perplexity": 94.37680116571767}, "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-2015-27/segments/1435375099105.15/warc/CC-MAIN-20150627031819-00271-ip-10-179-60-89.ec2.internal.warc.gz"} |
https://physics.stackexchange.com/questions/524108/string-landscape-de-sitter-vacua-and-broken-supersymmetry/553341 | # String Landscape, De Sitter vacua and Broken Supersymmetry
If we assume that the swampland conjectures, etc. regarding de sitter vacuas existence in the string / F-theory landscape turn out to be incorrect (and therefore we can assume the problem is well-posed), would all such solutions have broken supersymmetry?
There are a number of obvious “difficulties” with formulating (at least for the case of generic qft on curved spacetime) particle theories on de Sitter like spaces (ex. non-trivial hamiltonian from vanishing of globally timelike killing vectors, etc.). One feature of de Sitter space, that is probably obvious but likely not trivial (at least from first glance) is the non-existence of positive conserved energy and its requirement for broken supersymmetry.
Have I made an error, or is this a “just so” theorem regarding de Sitter vacua and the necessity for broken supersymmetry?
• My reasoning for believing susy must be broken is as follows: if susy were not broken (with the positive energy condition in mind) the supercharge would be hermitian and pick up non zero value, and its square would be forced non-zero, and would be a conserved positive (?) bosonic value. This doesn’t make sense (unless I’m missing something) forcing susy to be broken by necessity. – alex sharma Jan 10 '20 at 0:38
• If SUSY was unbroken then we would've detected it. – redhood Apr 8 '20 at 19:23
• – Qmechanic Apr 8 '20 at 19:39
• @Qmechanic thank you, i appreciate the link. – alex sharma Apr 9 '20 at 5:22
## 1 Answer
You're right. Realistic string compactifications require four macroscopic dimensions. For supersymmetry to exist in a given background a non zero globally defined Killing spinor is required. In the d=4 case such a spinor should be (locally) the generator of the $$Spin(4,1)$$ group, the problem is that $$Spin(4,1)$$ has no Majorana representations (condition required to realize supersymmetry in a unitary way). Nevertheless, non unitary realizations of supersymmetry over de-Sitter space are possible.
There are papers in the literature claiming to surpass many of the mathematical subtleties. But to my poor knowledge no one is really popular among the experts. See https://arxiv.org/abs/1403.5038
Polyakov arguments about fundamental instabilities in de-Sitter cosmologies are also very nice and strongly physical. See for example https://arxiv.org/abs/1209.4135, https://arxiv.org/abs/0709.2899 or https://www.youtube.com/watch?v=Gn87Fu8QHYI. | {"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": 2, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8252964019775391, "perplexity": 641.3892076901951}, "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-2021-17/segments/1618039626288.96/warc/CC-MAIN-20210423011010-20210423041010-00165.warc.gz"} |
https://docs-cupy.chainer.org/en/stable/reference/generated/cupyx.scipy.sparse.linalg.lsqr.html | # cupyx.scipy.sparse.linalg.lsqr¶
cupyx.scipy.sparse.linalg.lsqr(A, b)
Solves linear system with QR decomposition.
Find the solution to a large, sparse, linear system of equations. The function solves Ax = b. Given two-dimensional matrix A is decomposed into Q * R.
Parameters: A (cupy.ndarray or cupyx.scipy.sparse.csr_matrix) – The input matrix with dimension (N, N) b (cupy.ndarray) – Right-hand side vector. Its length must be ten. It has same type elements as SciPy. Only the first element, the solution vector x, is available and other elements are expressed as None because the implementation of cuSOLVER is different from the one of SciPy. You can easily calculate the fourth element by norm(b - Ax) and the ninth element by norm(x). tuple | {"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": 0.7074142098426819, "perplexity": 1838.5909886778245}, "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/1552912204736.6/warc/CC-MAIN-20190325234449-20190326020449-00385.warc.gz"} |
https://www.physicsforums.com/threads/work-of-a-spring-derivation.667903/ | # Work of a Spring Derivation
1. Jan 29, 2013
### MrLiou168
1. The problem statement, all variables and given/known data
A spring with stiffness k and unstretched length L is stretched so the elongation is d = x2 - L. A force is applied to make the final length of the spring x2. What is the work done by the force in terms of d?
2. Relevant equations
W = F * d = F*dx
d = x2 - L
F = k*dx
3. The attempt at a solution
Assuming W = F*dx and F = k*dx, then I derived F = k(x2 - L) = k*d
And plugging F back into the work equation, I got W = (kd)*d which is W = kd^2.
However, isn't the actual equation for work done by a spring W = (kx^2)/2? I can't seem to find where I missed the factor of 1/2. Any help greatly appreciated!
2. Jan 29, 2013
### Staff: Mentor
You assumed in your derivation that the force was constant and equal to its maximum value. Not so. As the spring is stretched, the force starts at zero and only reaches k*d at its full extension.
3. Jan 29, 2013
### MrLiou168
Thanks Doc. So in this case would I simply integrate to find W? As in W = integral (F*dx)
and then W = integral(kxdx) = (kd^2)/2 ...?
4. Jan 29, 2013
### Staff: Mentor
Exactly.
Similar Discussions: Work of a Spring Derivation | {"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": 0.9488871097564697, "perplexity": 1426.3211144830402}, "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/1502886103167.97/warc/CC-MAIN-20170817092444-20170817112444-00637.warc.gz"} |
https://www.groundai.com/project/pressure-induced-unusual-metallic-state-in-eunio_3/ | Pressure-induced unusual metallic state in EuNiO{}_{3}
# Pressure-induced unusual metallic state in EuNiO3
Hisao Kobayashi Graduate School of Material Science and Center for Novel Material Science under Multi-Extreme Conditions, University of Hyogo, Koto Hyogo 678-1297, JAPAN Shugo Ikeda Graduate School of Material Science and Center for Novel Material Science under Multi-Extreme Conditions, University of Hyogo, Koto Hyogo 678-1297, JAPAN Yoshitaka Yoda Japan Synchrotron Radiation Institute, Hyogo 679-5198, JAPAN Naohisa Hirao Japan Synchrotron Radiation Institute, Hyogo 679-5198, JAPAN Yasuo Ohishi Japan Synchrotron Radiation Institute, Hyogo 679-5198, JAPAN J. A. Alonso Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, SPAIN M. J. Martinez-Lope Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, SPAIN R. Lengsdorf II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, GERMANY D. I. Khomskii II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, GERMANY M. M. Abd-Elmeguid II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, GERMANY
July 26, 2019
###### Abstract
The perovskite antiferromagnetic ( 220 K) insulator EuNiO undergoes at ambient pressure a metal-to-insulator transition at = 460 K which is associated with a simultaneous orthorhombic-to-monoclinic distortion, leading to charge disproportionation. We have investigated the change of the structural and magnetic properties of EuNiO with pressure (up to 20 GPa) across its quantum critical point (QCP) using low-temperature synchrotron angle-resolved x-ray diffraction and Eu nuclear forward scattering of synchrotron radiation, respectively. With increasing pressure we find that after a small increase of ( 2 GPa) and the induced magnetic hyperfine field at the Eu nucleus ( 9.7 GPa), both and are strongly reduced and finally disappear at 10.5 GPa, indicating a magnetic QCP at . The analysis of the structural parameters up to 10.5 GPa reveals no change of the lattice symmetry within the experimental resolution. Since the pressure-induced insulator-to-metal transition occurs at 6 GPa, this result implies the existence of an antiferromagnetic metallic state between 6 and 10.5 GPa. We further show from the analysis of the reported high pressure electrical resistance data on EuNiO at low-temperatures that in the vicinity of the QCP the system behaves as non-Fermi-liquid, with the resistance changing as , with n=1.6, whereas it becomes a normal Fermi-liquid, n = 2, for pressures above 15 GPa. On the basis of the obtained data a magnetic phase diagram in the (, ) space is suggested.
PACS numbers
71.30.+h, 62.50.-p, 71.28.+d, 76.80.+y
preprint:
## I Introduction
The study of magnetic quantum transitions in strongly correlated electron systems has been the subject of continuous interest due to the observation of novel ground states near/at the magnetic-to-nonmagnetic transition leading to quantum critical point (QCP). Known examples are heavy-fermion metals where non-Fermi-liquid (NFL) phases (e.g. CeCuAu lohneysen96 (); lohneysen98 () and YbRhSi custers03 ()) and unconventional superconductivity (e.g. CePdSi mathur98 () and UGe saxena00 ()) appear.
Another promising but different class of systems for such studies are strongly correlated transition metal oxides khomskii14 () (e.g. O perovskites, = rare earth ion; = transition metal). The key aspect of these materials is that the interplay between spin, charge, and orbital degrees of freedom leads to the existence of several competing phases and in turn to complex and unusual phase diagrams imada98 (); dagotto05 (). Of particular interest are magnetically ordered transition metal oxides, in which a metal-to-insulator (MI) transition as well a magnetic-to-nonmagnetic transition can be tuned by external pressure. In this context, a central issue is what is the impact of those degrees of freedom on the ground state properties when a magnetic insulator is tuned to a nonmagnetic metal across a QCP.
In this respect, the perovskite rare earth nickelates NiO ( La) are excellent candidates for such studies as they exhibit an insulating antiferromagnetic (AF) ground state: The phase diagram of the NiO series is shown in Fig. 1. They display a well-defined MI transition at a temperature which increases with decreasing the size of ion ( = 130 K (Pr), cc, 600 K (Lu) torrance92 (); medarde97 ()). Simultaneously the lattice symmetry changes from orthorhombic () to monoclinic () which contains two nonequivalent Ni-sites (NiO) octahedra with slightly different Ni-O bond lengths, indicating charge disproportionation (CD), 2Ni Ni + Ni alonso99_0 (); alonso99_1 (); mizokawa00 ().
Another though related interpretation of the phenomena occurring at the MI transition is the important role of oxygen holes mizokawa00 (); johnston14 (), which play a very important role in these materials with negative charge-transfer gap zaanen85 (). This picture is actually very close to the picture of disproportionation to more and less covalent Ni sites, proposed by Goodenough goodenough96 () and in Ref. zhou04_0 (). As a matter of fact, in reality both these pictures are different sides for the same phenomenon, with the charges on Ni sites more different for smaller rare earths in the series NiO, and more equivalent for larger . Further on we denote both these pictures as CD.
Recently, resonant x-ray diffraction staub02 (); scagnoli06 (), Raman spectroscopic studies zaghrioui01 () and high resolution x-ray absorption at the Ni -edge medarde09 () indicate the existence of CD in the whole NiO series. Moreover, very recent studies on NiO using soft x-ray magnetic powder diffraction bodenthin11 () demonstrate that the NiO compounds have very similar electronic and magnetic states despite the large variation of the value of their .
At low temperatures, the transition to AF ordered state is also related to the size of the ion, i.e. for large ions ( = Pr and Nd) the MI transition occurs simultaneously with an antiferromagnetic (AF) ordering of the (Ni) sublattice (i.e. ), whereas for smaller ( = Sm Lu) ions, is much lower than (e.g. for EuNiO, = 220 K and = 463 K). The magnetic structure in the Ni sublattice of NiO proposed by neutron-powder diffraction alonso99_0 (); garcia92 (); rodriguez98 () has a magnetic propagation vector =(1/2,0,1/2) and consists of an up-up-down-down stacking of Ni magnetic moments. An alternative non-collinear magnetic structure with the same propagation vector is recently suggested by resonant soft x-ray magnetic diffraction studies on NiO scagnoli06 (); bodenthin11 (); scagnoli08 ().
As mentioned above, according to the magnetic phase diagram of the NiO series at ambient pressure (see Fig. 1), the ground state changes from an antiferromagnetic insulating ( La) to a nonmagnetic metallic state ( = La) through a QCP. Figure 1 shows the phase diagram in terms of the tolerance factor , which reflects the degree of distortion of perovskites and is determined by ratio of the relative -O and Ni-O bond lengths, and , . As the distortion is larger in for small ions, increases as the radius increases. The figure also shows that increases with increasing pressure. Regarding the effect of external pressure on and in NiO, only few compounds have been investigated up to very high pressure until now, in particular the pressure dependence of in them. While the initial change () up to about 2.8 GPa reveals a small increase of with pressure for = Sm, Eu and Gd zhou08 (), for NdNiO and PrNiO ( = ) is strongly reduced with pressure obradors93 (); canfield93 () and even suppressed to zero in PrNiO across a QCP zhou05 (). In the latter case a broad NFL behavior in the vicinity of the QCP has been reported zhou05 ().
In this work we study the pressure effect on the structural, transport and magnetic properties of one of perovskite nickelates, EuNiO. We have selected EuNiO ( = 463 K and = 220 K) which is one of typical NiO compounds with and thereby allows one to investigate the evolution of the magnetic state under high pressure across a QCP. The presence of Eu Mössbauer isotope in EuNiO allows us to realize such an investigation at a microscopic level using the Eu nuclear forward scattering (NFS) of synchrotron radiation - a technique based on the Mössbauer effect. The application of the Eu NFS technique allows one to probe the magnetic state of the Ni sublattice of EuNiO under pressure via the induced magnetic hyperfine (hf) field at the Eu nuclei which results from the ordered Ni magnetic moment. Some preliminary data which demonstrate the applicability of this technique on EuNiO have been published by some of the authors elsewhere (lengsdorf04 (), see below). The present Eu NFS data on EuNiO, in combination with low temperature synchrotron angle-resolved x-ray diffraction measurements up to about 20 GPa reveal a magnetic QCP at 10.5 GPa. Since the high pressure resistance data on EuNiO reveal a pressure-induced insulator-to-metal (IM) transition at 6 GPa lengsdorf04 (), the results suggest that for pressures between 6 and 10.5 GPa the pressure-induced metallic state is magnetically ordered. Similar metallic antiferronagnetic state was proposed in Ref. mazin07 (), and recently observed in strained multilayers of PrNiO/PrAlO hepting14 (). The presence of this state can be possibly explained by the picture of spin density wave lee11 (). As the lattice symmetry in this state in our system remains monoclinic, we suppose that certain CD exist in this case too, although we do not have definite proof of that. We further show from the analysis of the high pressure electrical resistivity data on EuNiO lengsdorf04 () that in different pressure ranges beyond the QCP both NFL and Fermi liquid (FL) regimes are realized.
It is worthwhile to mention that beside NiO bulk samples, rare earths nickelates are very actively studies nowadays as thin films and multilayers frano13 (); chakhalian14 (). In particular, one can effectively control their properties by using epitaxial strain (and spatial confinement) induced by the substrate, which is rather similar, but not identical to the pressure effects studied in this paper.
## Ii Experimental details
A polycrystalline sample of EuNiO was prepared under an oxygen pressure of 200 bars. Details of the preparation and characterization were published elsewhere alonso95 (). The Eu NFS experiments were carried out under pressure and at low temperature using a clamp-type diamond-anvil cell (DAC) on beamline BL09XU at SPring-8. The first excited nuclear state of Eu has an energy of 21.541 keV (resonance energy) and a half lifetime of 9.7 ns. The pulsed synchrotron radiation was monochromatized to a bandwidth of 1.8 meV at the resonant excitation energy of Eu nuclei by a high-resolution monochromator. The monochromatized x-ray transmitted through the sample was detected with the stacked Si-avalanche photodiodes. The storage ring was operated in a special bunch mode where the interval between successive single bunches is 165.2 ns which is much longer than the half lifetime of the first excited nuclear state. The powder-samples were loaded with ruby chips into a sample cavity of a 0.5 mm diameter in a 0.2 mm thick Inconel 625 alloy gasket and mixtures of methanol-ethanol as a pressure-transmitting medium to ensure hydrostatic conditions. Pressure was calibrated by measuring the wavelength shift of the luminescence line of ruby chips in the clamp-type DAC at room temperature.
The x-ray diffraction data were collected under pressure up to approximately 20 GPa at 8 K by the angle-dispersive technique and using an image-plate detector on beamline BL10XU at SPring-8. The incident x-ray wavelength was 0.4153 Å, which was calibrated by measuring the x-ray diffraction pattern of CeO at ambient conditions. The powder-samples were loaded into a He-gas driven DAC with ruby chips and He as a pressure-transmitting medium to ensure hydrostatic conditions. Pressure was calibrated by measuring the wavelength shift of the luminescence line of ruby chips in the DAC at 8 K.
## Iii Results and Discussion
### iii.1 High pressure 151Eu nuclear forward scattering
As mentioned above, the Eu NFS of synchrotron radiation allows one to probe the magnetic state of the Ni sublattice of EuNiO under pressure via the induced magnetic hf field at the Eu nuclei which results from the ordered Ni magnetic moment. originates from the exchange (transferred) field due the admixture of the magnetic () excited state into the nonmagnetic () ground state. The magnitude of depends both on the size and relative orientation of the Ni moments around the Eu nuclei. The first attempt to demonstrate the applicability of this technique on EuNiO has been reported in Ref. lengsdorf04 (). In this work the authors only measured two pressure points (9.5 and 14.4 GPa) and detected no magnetic signal at 14.4 GPa, and thus these preliminary measurements provided no information about the pressure dependence of or , which is necessary to construct a (, )-magnetic phase diagram. In the present work using the high pressure Eu NFS technique we performed systematic measurements of the pressure dependences of and of EuNiO and were able to locate the magnetic QCP and thus to construct the (, )-magnetic phase diagram of EuNiO.
Figures 2 (a) and (b) show some selected Eu NFS spectra at different pressures and temperatures, both in the paramagnetic stats (7.3 GPa at 300K and 10.7 GPa at 5 K) and magnetically ordered state (4.7, 7.3, and 9.7 GPa at 5 K). In all spectra, we observe quantum beats due to electric quadruple and/or magnetic hf interactions which cause splitting of the nuclear levels and thus lead to a constructive interference of the photons emitted from these energy levels. As seen in Fig. 2 (a), the frequencies of quantum beats in the Eu NFS spectra observed below 9.7 GPa at 5 K are higher than those in the spectrum at 10.7 GPa and 5 K. These high frequencies of the quantum beats come from large energy splitting due to magnetic hf splitting of the Eu nuclear levels in the magnetically ordered state. In comparison, the feature of low frequency in the Eu NFS spectrum on the paramagnetic state at 7.3 GPa and 300 K (Fig. 2 (b)) is similar to that at 10.7 GPa and 5 K shown in Fig. 2 (a). These results suggest that magnetic ordering in EuNiO disappears at 5 K above 10.7 GPa.
The fits to the Eu NFS spectra were performed using the program package MOTIF shvydko00 (), applying the full dynamical theory of nuclear resonant scattering and including the diagonalization of the complete hyperfine Hamiltonian. The spectra at 5 K and 10.7 GPa and at 7.3 GPa and 300 K can be fitted by assuming a pure electric quadrupole interaction, indicating a paramagnetic state in EuNiO at 5 K and 10.7 GPa. However, the Eu NFS spectra in the magnetically ordered state at 5 K below 9.7 GPa were impossible to fit by only quadrupole interaction; therefore they were fitted by assuming a combined quadrupole and magnetic hf interactions. In such a case, we have considered the magnetic structure of EuNiO at ambient pressure defined by the magnetic propagation vector k = (1/2,0,1/2) as determined by neutron-powder diffraction rodriguez98 (). In this magnetic structure, the single Eu site is subdivided into two magnetically nonequivalent Eu sites with the ratio of 1:1. One Eu site is sandwiched between two [111] (in cubic setting) layers with parallel spins, i.e., surrounded by six Ni atoms with spin up and two Ni atoms with spin down, sees a transferred hf field, while the other Eu site is nonmagnetic owing to the cancellation of the Ni antiparallel sublattice magnetic moments at these Eu sites rodriguez98 ().
As shown in Fig. 2 (a), the Eu NFS spectra at 5 K below 9.7 GPa were well fitted by assuming two different Eu sites with the ratio of 1:1, that is, one half of Eu nuclei has with both electric quadrupole and magnetic hf interactions, and the other has a small electric quadrupole interaction only. Consequently, these results suggest that the magnetic structure in the Ni sublattice of EuNiO does not change under pressure up to 9.7 GPa. The values refined at 5 K are shown in Fig. 2 (a) as a function of pressure. As seen in Fig. 3 (a), the refined values of gradually increases with increasing pressure up to 7.3 GPa, passes through a maximum around 8 GPa, and then disappears at 10.7 GPa, indicating a suppression of Ni magnetic moments.
To obtain the pressure dependence of , we have analyzed temperature dependences of the Eu NFS spectra at different pressures on the basis of the fitting procedure (see above). Figure 2 (b) shows that the analytical spectra well reproduce the observed ones within the assumptions given above. The values of were evaluated from the temperature dependence of at different pressures (, ), using the Brillouin function with = 1/2. Figure 3 (b) shows the values of the pressure dependence of . As it is evident from Fig. 2 (b), slightly increases with pressure up to about 2 GPa. At higher pressures decreases and then collapses at about 10.5 GPa, indicating the collapse of magnetic order of the Ni moments in EuNiO. The initial increase of with pressure ( 2.4 GPa) is in a good agreement with the data of EuNiO reported from resistivity in Ref. zhou08 () and reflects the localized character of the Ni 3-states in the insulating phase of EuNiO.
Thus, the Eu NFS results reveal that with increasing pressure both and disappear at 10.5 GPa. Keeping in mind that EuNiO displays the pressure-induced IM transition at 6 GPa lengsdorf04 (), this result implies that under pressure the ground state of EuNiO changes from AF insulator to AF metal at and then to a nonmagnetic metal above . The impact of this finding on the complexity (, )-phase diagram of EuNiO will be discussed in the following sections.
### iii.2 High pressure synchrotron angle-resolved x-ray diffraction at 8 K
Figure 4 shows some selected integrated x-ray diffraction patterns of EuNiO under pressure at 8 K. In the inset of Fig. 4 (a), the diffraction line at 18 deg. in the pattern corresponds to the (224) refraction in the orthorhombic structure. This diffraction line may split to two (224) and (22) refractions in the monoclinic structure. But, as it is also known from the structural data on NdNiO staub02 () and PrNiO medarde09 (), the monoclinic distortion in rare earth nickelates with larger rare earths is very small and difficult to detect directly. That is why it took long time, and required the use of novel, more sophisticated techniques, to finally establish that also these systems NiO, with larger ions, have monoclinic structure at low temperatures staub02 (); scagnoli06 (); medarde09 (). The situation is the same in our case: as seen in the inset of Fig. 4 (a), we did not observe the monoclinic distortion in EuNiO within our experimental resolution. All diffraction lines in the x-ray diffraction patterns are labeled with the indices of the orthorhombic structure. But these results indicate at least that there is no other pressure-induced structural symmetry change up to 20 GPa at 8 K, within our experimental resolution.
Integrated x-ray diffraction patterns were analyzed with the Rietveld refinement program RIETAN-2000 izumi00 () using the orthorhombic structure. In each x-ray diffraction pattern, the regions at 2 7.2, 8.4 and 12.2 deg. were excluded from the refinement procedure where very weak diffraction lines from impurity phases were observed. All integrated x-ray diffraction lines in the patterns up to 20 GPa gave good fits as shown in Fig. 4. It should be noted that these refinement procedures were used to derive individual atomic coordination parameters in addition to the lattice parameters.
In Fig. 5 (a), we show the pressure dependence of the refined lattice parameters of EuNiO at 8 K. As shown in Fig. 5 (a), the pressure dependences of = , = , and = 2 exhibit no discontinuity up to 10.5 GPa, indicating within the experimental resolution no structural phase transition at 6 GPa. These pressure variations further reveal that the pressure dependences of , and are quite different. With increasing pressure, the value of decreases more rapidly than those of and and the value of almost saturates at 10.5 GPa. However, no change of the lattice symmetry is observed.
The linear compressibilities of the lattice parameters were estimated to be = 1.11(2), = 2.52(3), and =1.20(1) GPa below 10.5 GPa. The estimated value of is twice larger than those of and . Furthermore, the pressure dependences of and are different from those at room temperature lengsdorf04 (). The bulk moduli below 10 GPa and above 11 GPa were evaluated based on the Murnaghan equation,
p=BB′[(V0V)B′−1], (1)
where is the ambient-pressure volume and represents a pressure derivative of . The solid lines in Fig. 5 (b) represent the best-fitting curves obtained and the values were refined to be 195(2) and 232(4) GPa below 10 GPa and above 11 GPa, respectively. The value refined below 10 GPa is comparable with those refined at room temperature lengsdorf04 (); zhou04 ().
Of particular interest is our finding that no change of the lattice symmetry has been observed in metallic magnetic ground state for 6 GPa 10.5 GPa. One possibility is that the monoclinic distortion associated with CD is too weak to be detected by our measurements. But the alternative is that the CD is still preserved to some extent also in the metallic state in EuNiO above 6 GPa. This possibility does not contradict our results of Eu NFS in the AF metallic state. In this respect, we want to mention that such an unusual ground state has been predicted in and observed under high pressure in similar compounds orbitally degenerate compounds (e.g. YNiO mazin07 ()).
Regarding the observed anomalous pressure dependence of the lattice parameter for 10.5 GPa, it is obvious that the anomaly of is not related to the pressure-induced IM transition at 6 GPa but rather corresponds to the transition from the antiferromagnetic metallic to a nonmagnetic metallic state at , i.e. at the magnetic QCP of EuNiO. The origin of this anomaly will be discussed in Section C.
### iii.3 Magnetic and electronic transitions versus structural parameters
In the following, we would like discuss the structural response to the pressure-induced IM transition and magnetic QCP in EuNiO. In the inset of Fig. 5 (a), we show the pressure dependence of the effective bandwidth as deduced from the structural parameters, which reveals a significant increase around the pressure-induced IM transition ( 6 GPa). is known to be related to the ligand-to-metal hybridization (effective hopping) and can be described in NiO compounds in terms of the Ni-O bond length and the Ni-O-Ni bond angle by the relation of harrision80 (). Thus an increase of implies a corresponding increase of the effective hopping which is expected as the system is tuned to a metallic state. The averaged and values of EuNiO under pressure were evaluated from the refined lattice and individual atomic coordination parameters to estimate the averaged value under pressure comm (). Obviously the pressure-induced increase of above the pressure-induced IM transition ( 6 GPa) reflects the onset of the metallic state in EuNiO.
On the other hand, is also related to () through the perturbation formula for insulators khomskii14 ():
TN∼J∼t2dd⎛⎜⎝1Udd+1Δ+Upp2⎞⎟⎠,tdd=t2pd/Δ (2)
where is the on-site - Coulomb interaction energy, the effective hoping matrix element, describes the ligand-to-metal charge-transfer energy, and is the Coulomb repulsion of the two holes at the oxygen site. As shown in Fig. 2 (b), the pressure dependence of in the insulating phase of EuNiO ( 6 GPa) reveals an increase with pressure up to about 2.4 GPa, followed by a decrease upon approaching the pressure-induced IM transition, whereas monotonously increases in the whole insulator phase ( 6 GPa). Such a deviation from a linear correlation between and in magnetic insulators zhou08 () reflects the proximity to a crossover from localized to itinerant electronic behavior in EuNiO above about 2.4 GPa. This is in agreement with the picture proposed by Zhou . zhou03 () to explain the pressure-induced magnetic properties in the NiO series.
Now, we would like to provide an explanation of the observed anomalous behavior of the lattice parameter across the QCP at 10.5 GPa. The pressure-induced change of the lattice parameter is governed by two competing mechanisms that act in opposite ways: (i) the decrease of the average Ni-O bond length due to compression of the NiO octahedra which leads to a gradual with pressure; and (ii) the increase of the average Ni-O-Ni bonding angle which results in a reduction of the tilting of NiO octahedra and thereby an with pressure. We argue that below 10.5 GPa the compression of (i) is the dominating factor and prevails in the pressure dependence of , leading to a decrease of with pressure. However, at and beyond the QCP the compression of becomes weaker and comparable to that due to the increase of (ii). We believe that this could be related to a corresponding change of the magnetoelastic coupling at and beyond the QCP. As a result, the two competing mechanisms become almost equal and compensate each other, causing a nearly pressure independent change of the lattice parameter for 10.5 GPa. In such a case, one would anticipate melting of the charge disproportionation in the nonmagnetic metallic state, caused by the increased bandwidth.
### iii.4 Suggested (p, T)-phase diagram of EuNiO3
On the basis of our Eu NFS and low temperature synchrotron x-ray data, we would like to propose the (, )-phase diagram for EuNiO, shown in Fig. 6. The overall features of the phase diagram can be summarized as follows: at ambient pressure below 460 K the system undergoes a transition from the orthorhombic metallic state to a monoclinic CD insulating state. The insulating CD state exhibits antiferromagnetic ordering below 220 K. Under pressure, this AF insulating and CD ground state changes to an AF metallic and CD state at 6 GPa. At higher pressures the system displays a transition to a nonmagnetic state at 10.5 GPa i.e. QCP. By further increasing pressure beyond the QCP, the system reveals NFL and FL behavior for 10.5 GPa 14.8 GPa and 15.9 GPa 17.5 GPa, respectively. The identification of NFL and FL regions are based on the analysis of the original low temperature electrical resistance data on EuNiO reported in Ref. lengsdorf04 (). To analyze the electrical resistance data (), we used the power-law fitting to (, ) of EuNiO in the temperature range between 10 and 45 K with ()(=()-) , where n = 2 and 1 n 2 for FL and NFL behavior, respectively. As shown in Figs. 7 (a) and (b), the power-law with n = 1.6 fits the experimental data fairly well for = 11.5, 13.2 and 14.8 GPa, indicating NFL behavior, whereas n = 2 is the best fitting for 15.9 and 17.5 GPa, corresponding to FL behavior. Our finding of a NFL behavior in EuNiO with n = 1.6 is similar to that reported from high pressure resistivity data on PrNiO zhou05 (). The authors show in addition that the suppression of the insulating state of PrNiO ( = 130K ) above 1.3 GPa is accompanied by a transformation to a NFL phase in which the resistivity varies proportional to with n = 1.33 and 1.6 over a broad pressure range. In EuNiO with , we only observe a NFL behavior with n=1.6.
## Iv Summary
We have investigated the pressure effect up to about 20 GPa on the structural and magnetic properties of the antiferromagnetic insulator rare earth nickelate EuNiO using low-temperature synchrotron angle-resolved x-ray diffraction and Eu nuclear forward scattering (NFS) of synchrotron radiation, respectively. The Eu NFS technique allows one to probe the magnetic state of the Ni sublattice of EuNiO under pressure via the induced magnetic hyperfine field at the Eu nuclei which originates from the ordered Ni magnetic moments, and thus to investigate the evolution of the magnetic state under high pressure across a quantum critical point. The experimental results can be summarized as follows.
EuNiO shows two transitions: an insulator-to-metal transition at 6 GPa (already reported) and magnetic-to-nonmagnetic transition with a quantum critical point at 10.5 GPa. In this context, we would to refer to the recent observation of similar metallic antiferromagnetic phase in PrNiO strained multilayers hepting14 ().
The analysis of the pressure dependence of the structural parameters revealed a significant increase of the effective bandwidth , which is related to effective hopping, around the pressure-induced IM transition ( 6 GPa). However, we did not detect, within the resolution of the x-ray measurements, any anomalies in the lattice parameters at the IM transition at 6 GPa, and have seen only slight change of the bulk modulus at the quantum phase transition at 10.5 GPa. This lets us suggest that most probably the charge disproportionation, existing in NiO in the insulating phase, survives to certain extent also in the metallic phase. Furthermore, we have shown from the analysis of reported high pressure resistance data on EuNiO at low-temperatures that in the vicinity of the QCP the system behaves as non-Fermi-liquid, the resistance behaving as , with n=1.6, whereas it becomes a normal Fermi-liquid, n = 2, for pressures above 15 GPa. Based on all obtained data we propose the (, )-phase diagram for EuNiO, shown in Fig. 6. We feel that the properties of other nickelates of this class might be similar to those revealed here, i.e. they may be representative also for other perovskite nickelates.
###### Acknowledgements.
The Eu NFS and x-ray diffraction experiments under pressure were performed at SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal Nos. 2010A1517, 2008B1460, and 2007A1450). M.M.A. and D.K. would like to thank the Deutsche Forschungsgemeinschaft (DFG) for the support through SFB 608. The work of D.K. was supported by the German project FOR 1346 and by Cologne University within the German Excellence Initiative.
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# Algebraic Complexity Seminar
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## Read-Once Oblivious Algebraic Branching Programs: Lower Bounds and Identity Testing (part I)
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https://m.mediawiki.org/wiki/Extension:PGFTikZ | # Extension:PGFTikZ
MediaWiki extensions manual
PGFTikZ
Release status: unmaintained
Implementation Tag
Description Parse PGF/TikZ input, generate and compile LaTeX file and upload resulting image
Author(s) Thibault Marin, Markus Bürkler
MediaWiki 1.20+
PHP 5.3+
Database changes No
Parameters
## Installation
• Download and place the file(s) in a directory called PGFTikZ in your extensions/ folder.
require_once "$IP/extensions/PGFTikZ/PGFTikZ.php"; • Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed. ### Configuration parameters The following parameters can be set in the LocalSettings.php page after loading the extension (the values given here are the default values): // Default resolution for generated images$wgPGFTikZDefaultDPI = 300;
// Full path to LaTeX executable
$wgPGFTikZLaTeXPath = 'latex'; // Command line options to LaTeX command$wgPGFTikZLaTeXOpts = 'no-shell-escape'
// Full path to dvips executable
$wgPGFTikZdvipsPath = 'dvips'; // Either use epstool+imagemagick or ghostscript to generate image$wgPGFTikZuseghostscript = true;
// Full path to 'epstool' executable
$wgPGFTikZepstoolPath = 'epstool'; // Full path to 'ghostscript' executable$wgPGFTikZghostScriptPath = 'gs';
// Use standalone LaTeX package
## Security
Since the extension internally compiles LaTeX documents from user input, security must be considered before deploying the extension on public wikis.
• Some of the possible attacks that must be considered when deploying a web-based LaTeX compilation system are described in the TUG article: "A web-based TeX previewer: The ecstasy and the agony" ([[1]]):
• Execution of the system commands via wfShellExec offers control on resource limits given to the system call using $wgMaxShellMemory and$wgMaxShellTime variables.
• The source stored in the LaTeX file can also compromise security. The texmf.cnf file can be used to block access to files from within the generated LaTeX file. See [[2]] for a discussion on the matter.
Please download the code found below and place it in $IP/extensions/PGFTikZ/. Note:$IP stands for the root directory of your MediaWiki installation, the same directory that holds LocalSettings.php.
Note that the bitbucket links will be closed once the latest version is merged in the mediawiki repository.
### version 0.3.0
The latest version (with fixes to work on Windows hosted wikis) (v0.3.0, waiting for mediawiki review) is available at: https://bitbucket.org/thibaultmarin/pgftikz_public/get/v0.3.0.zip
### Mediawiki repository
The extension can be retrieved directly from Git [?]:
• Browse code
• Some extensions have tags for stable releases.
• Each branch is associated with a past MediaWiki release. There is also a "master" branch containing the latest alpha version (might require an alpha version of MediaWiki).
Extract the snapshot and place it in the extensions/PGFTikZ/ directory of your MediaWiki installation.
If you are familiar with git and have shell access to your server, you can also obtain the extension as follows:
cd extensions/
git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/PGFTikZ.git
## Known problems
This is an early stage, expect rough edges. Known bugs/limitations include:
• When using preview and save repeatedly, edit conflicts might occur in some cases. The edit conflict redirects to a resolution page where the input PGF/TikZ code is mixed up with the image automatically generated description page. Cancelling the conflict (maybe even deleting the image) and regenerating the page should fix the problem.
• If two pages link to the same file with different content, the image will be re-compiled each time either page is displayed.
• Probably many more, please report them. | {"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": 0.7587335109710693, "perplexity": 9326.876924928978}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560627999003.64/warc/CC-MAIN-20190619163847-20190619185847-00015.warc.gz"} |
https://mathoverflow.net/questions/140510/pullback-of-lie-algebra-cocycles-along-cartan-connections | # pullback of Lie algebra cocycles along Cartan connections
For $H \hookrightarrow G$ an inclusion of Lie groups, with $\mathfrak{h} \hookrightarrow \mathfrak{g}$ the corresponding inclusion of Lie algebras, an $(H\hookrightarrow G)$-Cartan connection on a smooth manifold $X$ is a $G$-principal connection $\nabla$ on $X$ equipped with a reduction of its structure group to $H$ and such that at each point $x \in X$ the composite (for any local trivialization)
$$\phi_x : T_x X \stackrel{\nabla}{\longrightarrow} \mathfrak{g} \longrightarrow \mathfrak{g}/\mathfrak{h}$$
is a linear isomorphism.
Now suppose that the inclusion is normal so that $\mathfrak{k} := \mathfrak{g}/\mathfrak{h}$ is a Lie algebra. Then for $\mu \in \mathrm{CE}^{n+1}(\mathfrak{k})$ an $H$-invariant Lie algebra $(n+1)$-cocycle on $\mathfrak{k}$ (hence an $L_\infty$-map $\mu : \mathfrak{k} \to \mathbb{R}[n]$), pullback of $\mu$ along $\phi$ produces a differential $(n+1)$-form $\phi^\ast \mu \in \Omega^{n+1}(X)$.
In the special case that $X = G/H$ and $\nabla$ is the Maurer-Cartan form, then this differential form is just the left-invariant extension of the cocycle over the Lie group, and is closed.
For general $X$ the form $\phi^\ast \mu$ is not in general closed. Asking it to be closed is akin to famous integrability conditions for differential form data, say in the definition of $G_2$-manifolds.
I would like to know if this concept of pulling back Lie algebra cocycles along Cartan connections this way and asking the result to be closed has been considered in generality, and under which name.
Moreover, what I am really interested in is the generalization of this condition to the case that $\mathfrak{g}$ is an $L_\infty$-algebra, $\nabla$ a higher principal connection and $X$ a suitable smooth higher (derived) stack. For this case, has anything vaguely similar to the above general condition been considered and given a name?
• I don't think that this has been studied systematically, but there is a lot of invariant calculus on Cartan geometries avaialble to study the question. Are you aware of intereting examples in which $\mathfrak g/\mathfrak h$ is canonically a Lie algebra (i.e. with $\mathfrak h$-equivariant bracket)? I don't know a nice example of this sitatuion. – Andreas Cap Dec 26 '14 at 10:18
• Thanks for your comment. My main motivating class of examples is that where $\mathfrak{g}$ is an extended super-Poincare Lie algebra and $\mathfrak{h}$ is the Lie algebra of the Lorentz group. Then $\mathfrak{g}/\mathfrak{h}$ is extended Minkowski-spacetime regarded as a super-translation Lie algebra. There are a finite number of exceptional super-Lie algebra cocycles on these, and in supergravity theory it is of key interest to prolong these to closed forms over a curved superspacetime, hence over an $(\mathfrak{h} \hookrightarrow \mathfrak{g})$-Cartan geometry. – Urs Schreiber Dec 27 '14 at 14:03
• I am not really familiar with the super-setting, but this sounds like a super-version of conformal geometry (which I am very familiar with). It seems to me that to do what you intend, you would need an action of $\mathfrak h$ on the space $V$ in which the cocycle has values in such a way that the action of $\mathfrak g/\mathfrak h\times V\to V$ is $\mathfrak h$-equivariant. I am not aware of examples of this in the usual conformal setting, but would be very intersted to get references for the cases you mention. – Andreas Cap Dec 28 '14 at 11:07
• Literature on the cocycles that I am thinking of is listed here: ncatlab.org/nlab/show/… Discussion of the need to prolong these to closed forms on curved superspace is listed here: ncatlab.org/nlab/show/… I am preparing some notes on this extension problem. Will send you more once its ready. – Urs Schreiber Dec 28 '14 at 17:47
The closest to this I have ever come is the work of Calderbank and Diemer (http://arxiv.org/abs/math/0001158) from the realm of Cartan geometries modelled on a pair $(G,P)$ for a parabolic subgroup $P$. They start with finite-dimensional irreducible $\mathfrak{g}$-representation $\mathbb{V}$ and construct a homotopy transfer from the twisted deRham sequence (it is in general no longer a complex: $(d^\nabla)^2 s= R\cdot s$) on exterior forms with values in the bundle associated to $\mathbb{V}$ to bundles associated to Lie algebra homology of the nilradical of $\mathfrak{p}$ with values in $\mathbb{V}$. In this way some curved infinity structures arise on the sections of homology bundles, whose operators are actually multi-differential operators. These structures have not been much exploited yet. The good thing is that one always has some control over the kernel of these operators between sections of homology bundles. E.g., there is an injection from the $\nabla$ parallel sections into the kernel of the operator acting on sections of the zeroth homology bundle with values in sections of the first homology bundle. In general, forms with values in $\mathcal{V}$ that are closed give rise to some special solutions of "geometric" 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": 0.8835493922233582, "perplexity": 251.80573767886582}, "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/1606141733122.72/warc/CC-MAIN-20201204040803-20201204070803-00538.warc.gz"} |
http://accessmedicine.mhmedical.com/Content.aspx?bookId=331§ionId=40726820 | Chapter 84
Cancers are characterized by unregulated cell growth, tissue invasion, and metastasis. A neoplasm is benign when it grows in an unregulated fashion without tissue invasion. The presence of both features is characteristic of malignantneoplasms. Cancers are named based on their origin: those derived from epithelial tissue are called carcinomas, those derived from mesenchymal tissues are sarcomas, and those derived from hematopoietic tissue are leukemias or lymphomas.
Cancers nearly always arise as a consequence of genetic alterations. Choriocarcinoma may be an exception to this rule in that experimental insertion of a choriocarcinoma cell into an animal blastocyst can result in the neoplastic cell giving rise to normal body structures under the inductive influence of the developing embryo. Such an occurrence would be unlikely in the setting of irreversible genetic damage.
Occasional cancers appear to be caused by an alteration in a dominant gene that drives uncontrolled cell proliferation. Examples include chronic myeloid leukemia (abl) and Burkitt's lymphoma (c-myc). The genes that can promote cell growth when altered are often called oncogenes. They were first identified as critical elements of viruses that cause animal tumors; later it was found that the viral genes had normal counterparts with important functions in the cell and had been captured and mutated by viruses as they passed from host to host.
However, the vast majority of human cancers are characterized by multiple genetic abnormalities, each of which contributes to the loss of control of cell proliferation and differentiation and the acquisition of capabilities, such as tissue invasion and angiogenesis. Many cancers go through recognizable steps of progressively more abnormal phenotypes: hyperplasia, to adenoma, to dysplasia, to carcinoma in situ, to invasive cancer (Table 84–1). These properties are not found in the normal adult cell from which the tumor is derived. Indeed, normal cells have a large number of safeguards against uncontrolled proliferation and invasion.
Table 84–1 Phenotypic Characteristics of Malignant Cells
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### AccessMedicine Full Site: One-Year Subscription
Connect to the full suite of AccessMedicine content and resources including more than 250 examination and procedural videos, patient safety modules, an extensive drug database, Q&A, Case Files, 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": 0.178047314286232, "perplexity": 3814.6143407911172}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-40/segments/1474738663202.87/warc/CC-MAIN-20160924173743-00299-ip-10-143-35-109.ec2.internal.warc.gz"} |
https://documen.tv/question/which-of-the-following-statements-are-true-check-all-that-apply-a-the-resistance-of-a-conductor-15095190-45/ | ## Which of the following statements are true? Check all that apply. A)The resistance of a conductor is proportional to
Question
Which of the following statements are true?
Check all that apply.
A)The resistance of a conductor is proportional to the resistivity of the material of which the conductor is composed.
B)Semiconductors have resistivity values that are larger than those of insulators.
C)The resistance of a conductor is proportional to the conductivity of the material of which the conductor is composed.
D)A material that obeys Ohm’s law reasonably well is called an ohmic conductor or a linear conductor
E)Good conductors of electricity have larger conductivity values than insulators.
in progress 0
6 months 2021-08-27T06:46:19+00:00 1 Answers 0 views 0
A)The resistance of a conductor is proportional to the resistivity of the material of which the conductor is composed.
D)A material that obeys Ohm’s law reasonably well is called an ohmic conductor or a linear conductor
E)Good conductors of electricity have larger conductivity values than insulators.
Explanation:
Let’s analyze each statement separately:
A)The resistance of a conductor is proportional to the resistivity of the material of which the conductor is composed. –> TRUE.
The resistance of a conductor is given by
where
is the resistivity of the material
L is the length of the conductor
A is its cross-sectional area
From the formula, we see that the resistance is proportional to the resistivity.
B)Semiconductors have resistivity values that are larger than those of insulators. –> FALSE.
Insulators are material in which electrons cannot travel freely, so they do not conduct electricity well, and so their resistivity is very high. On the other hand, semiconductor can conduct electricity (electrons are able to move), so their resistivity is lower than insulators.
C)The resistance of a conductor is proportional to the conductivity of the material of which the conductor is composed. –> FALSE.
The resistance of a conductor (R) is actually inversely proportional to the conductivity of the material:
where is the conductivity.
D)A material that obeys Ohm’s law reasonably well is called an ohmic conductor or a linear conductor –> TRUE.
For ohmic conductors, the relationship between voltage and current is linear, and it is given by Ohm’s law:
where V is the voltage, I the current, and R the resistance.
E)Good conductors of electricity have larger conductivity values than insulators. –> TRUE.
Conductivity is the reciprocal of resistance: the higher the conductivity, the better the material conducts electricity. So, good conductors have high conductivity, while insulators (which do not conduct electricity) have high resistance and low conductivity. | {"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": 0.9688446521759033, "perplexity": 801.0990428178153}, "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-2022-40/segments/1664030335469.40/warc/CC-MAIN-20220930113830-20220930143830-00599.warc.gz"} |
https://www.mothur.org/wiki/Memchi2 | # Memchi2
The memchi2 calculator returns a membership-based distance based on the Chi-squared statistic. This calculator can be used in the summary.shared, collect.shared, and dist.shared commands.
$D_{ab} = \sqrt{S_T \sum_{j=1}^{S_T} \left ( \frac {1}{S_{+j}} \left ( \frac{S_{Aj}}{S_{A+}} - \frac{S_{Bj}}{S_{B+}} \right )^2 \right ) }$
• where $S_{T}$ denotes the total number of OTUs observed between all samples
• where $S_{A+}$ denotes the number of nonzero OTUs in sample A.
• where $S_{B+}$ denotes the number of nonzero OTUs in sample B.
• where $S_{Aj}$ is 1 if the abundance of the jth OTU in sample A is greater than zero, otherwise 0.
• where $S_{Bj}$ is 1 if the abundance of the jth OTU in sample B is greater than zero, otherwise 0.
• where $S_{+j}$ is the number of samples that contain the jth OTU
Open the file 98_lt_phylip_amazon.fn.sabund generated using the Amazonian dataset with the following commands:
mothur > read.dist(phylip=98_lt_phylip_amazon.dist, cutoff=0.10)
mothur > cluster()
The 98_lt_phylip_amazon.fn.shared file will contain the following two lines:
0.10 forest 55 1 1 1 1 1 1 3 3 2 2 1 1 3 2 1 1 1 1 2 1 1 2 5 1 1 1 1 2 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0.10 pasture 55 0 0 0 1 1 0 1 0 0 5 0 0 0 0 0 2 0 0 0 3 0 0 2 1 0 1 0 0 0 0 0 0 1 2 1 1 1 1 1 7 1 1 2 1 1 1 1 1 1 1 1 1 2 1 1
This indicates that the label for the OTU definition was 0.10. The first line is from the forest sample and the second is from the pasture sample. There are a total of 55 OTUs between the two communities. Writing the data in a more presentable manner we see:
index forest pasture shared
1 1 0
2 1 0
3 1 0
4 1 1 X
5 1 0
6 1 0
7 3 1 X
8 3 0
9 2 0
10 2 5 X
11 1 0
12 1 0
13 3 0
14 2 0
15 1 0
16 1 3 X
17 1 0
18 1 0
19 2 0
20 1 3 X
21 1 0
22 2 0
23 5 2 X
24 1 1 X
25 1 0
26 1 1 X
27 1 0
28 2 0
29 1 0
30 1 0
31 1 0
32 1 0
33 1 1 X
34 0 2
35 0 1
36 0 1
37 0 1
38 0 1
39 0 1
40 0 7
41 0 1
42 0 1
43 0 2
44 0 1
45 0 1
46 0 1
47 0 1
48 0 1
49 0 1
50 0 1
51 0 1
52 0 1
53 0 2
54 0 1
55 0 1
Total 33 31 9
Using these sums to evaluate D we get:
$D_{ab} = \sqrt{ 55 \left[ \frac{\left(1/33-0/31\right)^2}{1} - \frac{\left(1/33-0/31\right)^2}{1} - \frac{\left(1/33-0/31\right)^2}{1} - \frac{\left(1/33-1/31\right)^2}{2} - ... \frac{\left(1/33-0/31\right)^2}{1} - \frac{\left(1/33-0/31\right)^2}{1} - \frac{\left(1/33-0/31\right)^2}{1} - \frac{\left(1/33-0/31\right)^2}{1} \right] }$
$D_{ab}$ = 1.572
Running...
mothur > summary.shared(calc=jclass)
...and opening 98_lt_phylip_amazon.fn.shared.summary gives:
label comparison memchi2
0.10 forest pasture 1.572314
These are the same values that we found above for a cutoff of 0.10. | {"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": 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": 0.8694418668746948, "perplexity": 356.51480033711636}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-26/segments/1560627998325.55/warc/CC-MAIN-20190616222856-20190617004856-00099.warc.gz"} |
https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=152&t=29219&p=90171 | ## Equation 18; Steric Factor
$V_{0} = \frac{V_{max}[S]}{K_{M} + [S]}; K_{M} = \frac{[E][S]}{[ES]}$
Diego Zavala 2I
Posts: 65
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time
### Equation 18; Steric Factor
Do we have to memorize the equation $k=P\times \sigma \upsilon _{rel}N\tfrac{2}{A} \times e^{-E_{A}/RT}$? I could not find it on the constants and equations sheet
Salman Azfar 1K
Posts: 50
Joined: Thu Jul 13, 2017 3:00 am
### Re: Equation 18; Steric Factor
I don't recall ever going over that equation in class and Dr. Lavelle usually emphasizes that we understand concepts rather than memorize stuff, so I highly doubt it. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 2, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.838007926940918, "perplexity": 6811.949317989961}, "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-2020-50/segments/1606141198409.43/warc/CC-MAIN-20201129123729-20201129153729-00563.warc.gz"} |
http://math.stackexchange.com/questions/228924/some-big-o-complexity-definition-proofs | # Some Big-O complexity definition proofs
I'm trying to prove (by definition) the following but to no avail:
• $n^{n/2} \ne O(3^{n/2})$
• $n! \ne O(3^n)$
• $(n-b)^a = \Theta(n^a)$
$a,b$ are both constants whereas $a > 0$ and $b$ might be positive, negative or $0$.
Now , here is what I come up so far:
Lets take the first one for example (regarding the others two I'm completly lost):
Now If we asssume by contradiction that $n^{n/2} = O(3^{n/2})$ then there exists constants $c,n_0>0$ such that $n^{n/2} < c(3^{n/2})$ for every $n\ge n_0$.
And if ones look at the ratio:
$n^{n/2} / 3^{n/2}$ then it can be proved that its going to infinity what implies that $n^{n/2}$ is much faster than $3^{n/2}$.
But I have no idea how to show this.
regarding the other ones , can you please give me an hint?
Thanks alot!
-
Problem 1: The solution by Karolis Juodelė is very efficient. Note for example that if $n \ge 12$, then $$\frac{n^{n/2}}{3^{n/2}}\ge \frac{12^{n/2}}{3^{n/2}}=4^{n/2}=2^n.$$ It is standard that $2^n\to\infty$ as $n\to\infty$.
For a less efficient solution, take the log of both sides, using any base $\gt 1$ that you like, such as $2$, or $e$, or $10$.
Problem 2: We want to show that $\dfrac{n!}{3^n}$ blows up, or equivalently that $\dfrac{3^n}{n!}$ approaches $0$. One way to do this is to observe that for $n \ge 6$, we have $$n!=(5!)(6)(7)(8)\dots(n)\ge (5!)(6)(6)\cdots(6)=(5!)(6^{n-5}).$$ But $3^n=(3^5)(3^{n-5})$. It follows that if $n\ge 6$ then $$\frac{3^n}{n!}\le \frac{3^5}{5!}\frac{3^{n-5}}{6^{n-5}}=\frac{3^5}{5!}\frac{1}{2^{n-5}}.$$ This inequality is plenty strong enough to deal with the problem. Note that a similar trick works if $3$ is replaced by, say, $100$.
Problem 3: We are interested in the ratios $$\frac{n^a}{(n-b)^a} \qquad \text{and}\qquad \frac{(n-b)^a}{n^a}$$ for large $n$. For either ratio, divide top and bottom by $n^a$. We get $$\frac{1}{\left(1-\frac{b}{n}\right)^a}\qquad \text{and}\qquad \left(1-\frac{b}{n}\right)^a$$ respectively. Both expressions have limit $1$ as $n\to\infty$.
-
I responded below. Thank you. – SyndicatorBBB Nov 5 '12 at 9:00
$f = O(g)$ iff $\lim \frac {f}{g} < \infty$. $f = \Theta(g)$ iff $f = O(g)$ and $g = O(f)$ which is the same as $0 < \lim \frac{f}{g} < \infty$.
1. $\lim \frac{n^{n/2}}{3^{n/2}} = \lim (\frac{n}{3})^{n/2}$. When does $\alpha^n$ go to infinity?
2. Notice that $n! > \frac {n^n}{e^n}$. Apply that and continue as before.
3. Not sure how to hint this. The fraction is bounded and decreasing.
-
but n/3 isn't an alpha. it depends on n. so its n^n... – SyndicatorBBB Nov 4 '12 at 15:49
Yes, my point was that, say $\lim 2^{n/2} = \infty$ and $\frac{n}{3} > 2$ for all large $n$. – Karolis Juodelė Nov 4 '12 at 15:52
Okay I will try to work with these hints. Thank you. – SyndicatorBBB Nov 4 '12 at 15:53
The characterizations of $O$ and $\Theta$ at the beginning of the post are overly restrictive because nothing ensures these limits exist. – Did Nov 5 '12 at 9:40 | {"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": 0.9856896996498108, "perplexity": 286.6807606270294}, "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-2014-10/segments/1394678698575/warc/CC-MAIN-20140313024458-00026-ip-10-183-142-35.ec2.internal.warc.gz"} |
http://www.maplesoft.com/support/help/MapleSim/view.aspx?path=ModelonHydraulics/Lines/Basic/LineEntrance | Line Entrance $—$ Entrance element of a long line
The LineEntrance component contains the equations for the entrance element (that is, the beginning of a long line). The connector port_A is used to connect the long line to another hydraulic component.
Connections
Name Description Modelica ID $\mathrm{oil}$ oil ${\mathrm{port}}_{A}$ Port A, where oil flows into the component ($0, ${p}_{B}<{p}_{A}$ means $0<\mathrm{Δp}$) port_A ${\mathrm{port}}_{B}$ Port A, where oil leaves the component ($q<0$, ${p}_{B}<{p}_{A}$ means $0<\mathrm{Δp}$) port_B
Parameters
General Parameters
Name Default Units Description Modelica ID steady-state init $\mathrm{false}$ If true, initialize in steady state steadyStateInit constant properties $\mathrm{true}$ If true, properties are treated as constant over time constantProperties elastic wall $\mathrm{false}$ If true, pipe properties affect speed of sound in oil elasticWall dynamic friction $\mathrm{false}$ If true, dynamic friction dynFriction ${\ell }_{\mathrm{element}}$ $m$ Length of one element ElementLength $d$ $m$ Line diameter diameter $\mathrm{Δh}$ $0$ $m$ Height difference heightDiff friction type [1] Type of flow model frictionType ${K}_{\mathrm{pipe}}$ Pipe bulk modulus of elasticity bulkModPipe roughness $0$ $m$ Roughness of pipe roughness ${\mathrm{\rho }}_{0}$ $\frac{\mathrm{kg}}{{m}^{3}}$ Constant density, if constantProperties is true rho0 ${\mathrm{\nu }}_{0}$ $\frac{{m}^{2}}{s}$ Constant viscosity, if constantProperties is true nu0 ${\mathrm{\beta }}_{0}$ $\mathrm{Pa}$ Bulk Modulus beta0 ${\mathrm{ΔT}}_{\mathrm{system}}$ $0$ $K$ Temperature offset from system temperature dT_system
[1] $\mathrm{Hydraulics.Lines.FrictionTypes.Laminar}$
Constant Parameters
Name Default Units Description Modelica ID ${\mathrm{\Delta }}_{\mathrm{rel}}$ $\frac{\mathrm{roughness}}{d}$ Relative roughness Delta
Constants
Name Value Units Description Modelica ID ${k}_{1}$ $0.192$ k1 ${k}_{2}$ $0.0948$ k2 ${k}_{3}$ $0.0407$ k3 ${\mathrm{\tau }}_{1}$ $0.25$ tau1 ${\mathrm{\tau }}_{2}$ $0.0352$ tau2 ${\mathrm{\tau }}_{3}$ $0.0024$ tau3 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 100, "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": 0.7586734294891357, "perplexity": 8477.109139453023}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-18/segments/1461860121090.75/warc/CC-MAIN-20160428161521-00024-ip-10-239-7-51.ec2.internal.warc.gz"} |
http://sci-gems.math.bas.bg/jspui/browse?type=author&sort_by=1&order=ASC&rpp=20&etal=-1&value=Nedel%E2%80%99ko%2C+Svetlana&starts_with=F | ## Browsing by Author "Nedel’ko, Svetlana"
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Issue DateTitleAuthor(s)Publisher
2007 Finding the Relationship between a Search Algorithm and a Class of Functions on Discrete Space by Exhaustive SearchNedel’ko, Victor; Nedel’ko, SvetlanaInstitute of Information Theories and Applications FOI ITHEA
Showing results 2 to 2 of 2 | {"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": 0.8121297359466553, "perplexity": 1168.7855380278447}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-50/segments/1480698542060.60/warc/CC-MAIN-20161202170902-00144-ip-10-31-129-80.ec2.internal.warc.gz"} |
http://math.stackexchange.com/questions/194612/how-can-i-create-a-function-that-simulates-a-linked-list | # How can I create a function that simulates a “linked list”?
If I have: { 0, 1, 2, 3, 4, 5, 6 }
How can I make a function that will return the number of steps to a target element, in one direction?
To clarify, let the target be 2... Say that x = 5, and I want my function to move backwards to find 2, and return -3.. And say that x = 0, it needs to return -5.
That's where I am confused.. Normally with my understanding of algebra, something like:
5 - x = 2 ==> x = 3
That satisfies my first scenario (if I negate it).. but, the second:
0 - x = 2 ==> x = -2 ... not what I want..
Is there some simple way to do this that I am not seeing?
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Is the answer you're looking for just to do the arithmetic mod the length of the list? So in the example you gave, $-2 \equiv 5 (\mod 7)$, so if the number is negative, you just return seven (the length in the general case) plus the number. – Luke Mathieson Sep 12 '12 at 9:53 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 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": 0.5973754525184631, "perplexity": 167.99429277249752}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-18/segments/1461860121976.98/warc/CC-MAIN-20160428161521-00202-ip-10-239-7-51.ec2.internal.warc.gz"} |
https://wiki.iac.isu.edu/index.php?title=DeltaDoverD_References&diff=52604&oldid=52603 | Data
Caption: The dashed line represents a pQCD prediction while the solid line represents the prediction from a hyperfine perturbed constituent quark model. The solid triangles are measurements from X. Zheng et al., Phys. Rev. Lett. 92 (2004) 012004 and the diamond are from Phys.Rev.D71:012003,2005. The squares represent a prediction of the precision obtained by a SIDIS measurement performed using and energy upgrade CEBAF and the upgraded CLAS. The risers represent systematic uncertainty and the error bar lines are statistical uncertainties.
File:Hep ex.0407032.pdf Quark helicity distributions in the nucleon for up, down, and strange quarks from semi-inclusive deep-inelastic scattering. By HERMES Collaboration (A. Airapetian et al.). DESY-04-107, Jul 2004. Published in Phys.Rev.D71:012003,2005. http://arXiv.org/pdf/hep-ex/0407032
Table XIV
File:Hep ex9906035.pdf Flavor Decomposition of the Polarized Quark Distributions in the Nucleon from Inclusive and Semi-inclusive Deep-inelastic Scattering, hep-ex/9906035 Hermes Data 1999
Table VII
Xbj Delta d/d Stat Err Sys Error
0.033 -0.1236 0.159 0.039
0.048 0.0588 0.1452 0.0543
0.065 -0.1336 0.1307 0.0362
0.087 -0.2572 0.1303 0.0495
0.0118 -0.4876 0.1185 0.0841
0.0166 -0.0918 0.1337 0.0675
0.239 -0.5218 0.1646 0.0822
0.339 -0.2799 0.1988 0.1694
0.447 -0.8133 0.4074 0.2454
File:Nucl ex0308011.pdf "Precision Measurement of the Neutron Spin Asymmetry A1n and Spin Flavor Decomposition in the Valence Quark Region." X. Zheng et al., Phys. Rev. Lett. 92 (2004) 012004.
Xbj Delta d/d Stat Err Sys Error
0.033 -0.274 0.032 0.013 0.01
0.047 -0.291 0.057 0.018 0.032
0.6 -0.324 0.083 0.031 0.089
In a previous version of the above work the values were
Xbj Delta d/d Stat Err Sys Error
0.033 -0.351 0.035 0.034
0.047 -0.939 0.063 0.053
0.6 -0.44 0.092 0.142
Asymmetries
File:Hep ex 0707.4077.pdf The Polarised Valence Quark Distribution from semi-inclusive DIS. By COMPASS Collaboration (M. Alekseev et al.). CERN-PH-EP-2007-024, Jul 2007. 10pp. Published in Phys.Lett.B660:458-465,2008.
Quark helicity distributions in the nucleon for up, down, and strange quarks from semi-inclusive deep-inelastic scattering. By HERMES Collaboration (A. Airapetian et al.). DESY-04-107, Jul 2004. Published in Phys.Rev.D71:012003,2005. e-Print: hep-ex/0407032
Fragmentation
File:Hep ph 0108055.pdf Fragmentation functions from semiinclusive DIS pion production and implications for the polarized parton densities. Stefan Kretzer, (Michigan State U.) , Elliott Leader, (Imperial Coll., London) , Ekaterina Christova, (Sofiya, Inst. Nucl. Res.) . MSU-HEP-10702, Aug 2001. 19pp. Published in Eur.Phys.J.C22:269-276,2001.
Hadronization in polarized semi-inclusive DIS: The Question of independent fragmentation.
Aram Kotzinian, (Turin U. & INFN, Turin & Yerevan Phys. Inst. & Dubna, JINR) . Oct 2004. 10pp. Published in Eur.Phys.J.C44:211,2005. e-Print: hep-ph/0410093
NLO analysis
File:Hep-ph 0603236.pdf A.M. Sissakian AIX archive hep-ph/0603236
Inclusive method
File:0810.4718.pdf CLAS 12 Science Program, V. Burkert, 2008 | {"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": 0.8775405883789062, "perplexity": 29984.19620562608}, "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-2022-21/segments/1652662530066.45/warc/CC-MAIN-20220519204127-20220519234127-00718.warc.gz"} |
https://www.maplesoft.com/support/help/Maple/view.aspx?path=Formats/Pajek | Pajek - Maple Help
Pajek (.net) Graph Format
Pajek file format
Description
• Pajek is a text-based file format for storing a single directed or undirected graph.
• The GraphTheory[ImportGraph] and GraphTheory[ExportGraph] commands can read from and write to this format.
• The general-purpose commands Import and Export also support this format.
Examples
Import a Pajek file encoding the Petersen graph.
> $\mathrm{Petersen}≔\mathrm{Import}\left("example/petersen.net",\mathrm{base}=\mathrm{datadir}\right)$
${\mathrm{Petersen}}{≔}{\mathrm{Graph 1: an undirected unweighted graph with 10 vertices and 15 edge\left(s\right)}}$ (1)
> $\mathrm{GraphTheory}:-\mathrm{DrawGraph}\left(\mathrm{Petersen}\right)$
Import a Pajek file encoding the constellation Draco.
> $\mathrm{Draco}≔\mathrm{Import}\left("example/draco.net",\mathrm{base}=\mathrm{datadir}\right)$
${\mathrm{Draco}}{≔}{\mathrm{Graph 2: an undirected unweighted graph with 14 vertices and 14 edge\left(s\right)}}$ (2)
> $\mathrm{GraphTheory}:-\mathrm{DrawGraph}\left(\mathrm{Draco}\right)$
Export the Levi graph to a Pajek file in the home directory of the current user.
> $\mathrm{LG}≔\mathrm{GraphTheory}:-\mathrm{SpecialGraphs}:-\mathrm{LeviGraph}\left(\right)$
${\mathrm{LG}}{≔}{\mathrm{Graph 3: an undirected unweighted graph with 30 vertices and 45 edge\left(s\right)}}$ (3)
> $\mathrm{Export}\left("levi.net",\mathrm{LG},\mathrm{base}=\mathrm{homedir}\right)$
${1126}$ (4) | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 10, "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": 0.886487603187561, "perplexity": 6967.621168897574}, "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/1637964363445.41/warc/CC-MAIN-20211208053135-20211208083135-00212.warc.gz"} |
http://math.stackexchange.com/questions/125084/intervals-contained-in-finite-cover-for-mathbbr | # Intervals contained in finite cover for $\mathbb{R}$
Let $(A_i)_{i=1}^k$ be a collection of subsets of $\mathbb{R}$ with the property that $\mathbb{R}=\bigcup_{i=1}^k A_i$. Is it the case that for some $j$, there exists a subset $S\subseteq A_j$ which is almost an interval (in the sense that $S\cup N$ is an interval for some null set $N$)?
This is clearly false without the "almost". For example, if we take $k=2$, $A_1=\mathbb{Q}$, and $A_2=\mathbb{R}\setminus{Q}$, there are no intervals. However, the weaker statement I propose above certainly holds. Is it true in general?
-
Assuming measurability of the partition, it's still false for $k=2$ since there are sets such that they and their complement both meet every open interval in a set of positive measure. See, e.g., this question and answer: math.stackexchange.com/questions/57317 – user83827 Mar 27 '12 at 15:15
@ccc: How do you mean "assuming measurability"? The question is whether the statement is true in general -- if it's false assuming measurability, then it's false in general, no? – joriki Mar 27 '12 at 16:45
@joriki: Oh certainly, I just meant to imply that it's trivially false when nonmeasurable partitions are allowed. So I assumed that the question was asking about measurable partitions, in which case there's a little more work to do to build a counterexample. I should have phrased this less ambiguously. – user83827 Mar 27 '12 at 16:51
Lets $A_1:=\{ x=\lfloor x \rfloor. x_1x_2....\, |0.x_1x_3x_5.. \mbox{is periodic} \}$.
Let $A_2 = R \backslash A_1$. Then, I think, $R= A_1 \cup A_2$ doesn't have your property...
-
Consider $A_{1}=\bigcup_{p\in \mathbb{Z}} \left[p+\frac{1}{|p|+1},p+2-\frac{1}{|p|+1}\right]$ and consider $A_2=\mathbb{R}\setminus A_1$. These set cannot be written as a union of any interval!
-
You may have misunderstood the question. In this case $A_1$ is a union of intervals, so with $j=1$ there is clearly a subset $S\subseteq A_j$ which is an interval, for instance $S=[1+1/2,3-1/2]$. – joriki Mar 27 '12 at 17:26 | {"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": 0.9139218926429749, "perplexity": 169.16638039802575}, "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-2016-30/segments/1469257831769.86/warc/CC-MAIN-20160723071031-00306-ip-10-185-27-174.ec2.internal.warc.gz"} |
http://aimsciences.org/article/doi/10.3934/cpaa.2017110 | # American Institute of Mathematical Sciences
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November 2017, 16(6): 2227-2251. doi: 10.3934/cpaa.2017110
## Essential spectral singularities and the spectral expansion for the Hill operator
Received February 2017 Revised May 2017 Published July 2017
In this paper we investigate the spectral expansion for the one-dimensional Schrodinger operator with a periodic complex-valued potential. For this we consider in detail the spectral singularities and introduce new concepts as essential spectral singularities and singular quasimomenta.
Citation: O. A. Veliev. Essential spectral singularities and the spectral expansion for the Hill operator. Communications on Pure & Applied Analysis, 2017, 16 (6) : 2227-2251. doi: 10.3934/cpaa.2017110
##### References:
[1] M. S. P. Eastham, The Spectral Theory of Periodic Differential Operators, New York: Hafner, 1974. [2] M. G. Gasymov, Spectral analysis of a class of second-order nonself-adjoint differential operators, Fankts. Anal. Prilozhen, 14 (1980), 14-19. [3] I. M. Gelfand, Expansion in series of eigenfunctions of an equation with periodic coefficients, Sov. Math. Dokl., 73 (1950), 1117-1120. [4] F. Gesztesy and V. Tkachenko, A criterion for Hill's operators to be spectral operators of scalar type, J. Analyse Math., 107 (2009), 287-353. doi: 10.1007/s11854-009-0012-5. [5] W. Magnus and S. Winkler, Hill's Equation, New York: Inter. Publ. , 1966. [6] V. A. Marchenko, Sturm-Liouville Operators and Applications, Birkhauser Verlag, Basel, 1986. doi: 10.1007/978-3-0348-5485-6. [7] D. C. McGarvey, Differential operators with periodic coefficients in Lp(-∞, ∞), Journal of Mathematical Analysis and Applications, 11 (1965), 564-596. doi: 10.1016/0022-247X(65)90105-8. [8] D. C. McGarvey, Perturbation results for periodic differential operators, Journal of Mathematical Analysis and Applications, 12 (1965), 187-234. doi: 10.1016/0022-247X(65)90033-8. [9] V. P. Mikhailov, On the Riesz bases in L2(0, 1), Sov. Math. Dokl., 25 (1962), 981-984. [10] M. A. Naimark, Linear Differential Operators, George G. Harrap, London, 1967. [11] E. C. Titchmarsh, Eigenfunction Expansion (Part II), Oxford Univ. Press, 1958. [12] V. A. Tkachenko, Spectral analysis of nonself-adjoint Schrodinger operator with a periodic complex potential, Sov. Math. Dokl., 5 (1964), 413-415. [13] A. A. Shkalikov, On the Riesz basis property of the root vectors of ordinary differential operators, Russian Math. Surveys, 34 (1979), 249-250. [14] O. A. Veliev, The one dimensional Schrodinger operator with a periodic complex-valued potential, Sov. Math. Dokl., 250 (1980), 1292-1296. [15] O. A. Veliev, The spectrum and spectral singularities of differential operators with complexvalued periodic coefficients, Differential Cprime Nye Uravneniya, 19 (1983), 1316-1324. [16] O. A. Veliev, The spectral resolution of the nonself-adjoint differential operators with periodic coefficients, Differential Cprime Nye Uravneniya, 22 (1986), 2052-2059. [17] O. A. Veliev and M. Toppamuk Duman, The spectral expansion for a nonself-adjoint Hill operators with a locally integrable potential, J. Math. Anal. Appl., 265 (2002), 76-90. doi: 10.1006/jmaa.2001.7693. [18] O. A. Veliev, Uniform convergence of the spectral expansion for a differential operator with periodic matrix coefficients, Boundary Value Problems, Volume 2008, Article ID 628973, 22 pp. (2008). [19] O. A. Veliev, Asymptotic analysis of non-self-adjoint Hill's operators, Central European Journal of Mathematics, 11 (2013), 2234-2256. doi: 10.2478/s11533-013-0305-x. [20] O. A. Veliev, On the spectral singularities and spectrality of the Hill's Operator, Operators and Matrices, 10 (2016), 57-71. doi: 10.7153/oam-10-05.
show all references
##### References:
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https://mathoverflow.net/questions/55/supersingular-elliptic-curves | Supersingular elliptic curves
I've read that an elliptic curve is supersingular if and only if its endomorphism ring is an order in a quaternion algebra. Does anyone have a simple explanation of this (or a good reference)?
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I'm not sure what other people think, but I'd like to encourage people to either linkify their questions a little more, to help provide background, or explicitly provide background. I know I can't answer this sort of question, but I feel like I could easily be learning more just by reading it! – Scott Morrison Oct 2 '09 at 3:37
@Scott: I agree that including references (links) and background should be encouraged, but I wouldn't sweat it too much. It's not a huge MO sin to ask a terse question without references (especially once we have some 2000+ rep users who can edit it into shape), but askers should keep in mind that the more clear an informative you make your question, the more likely you are to get a good answer. – Anton Geraschenko Oct 2 '09 at 14:53
As Scott mentioned in his response, this (and more) was proven by Deuring: Max Deuring, Die Typen der Multiplicatorenringe elliptischer Funktionenko ̈rper, Abh. Math. Sem. Hamburg 14, 197–272 (1941). In this paper he further proves that the quaternion orders are maximal. I'm very interested in seeing a proof of this, but don't know any German. So my question is, does anybody know if this paper has been translated into english? If not, does anybody know of a place where the latter fact (about the orders being maximal) is proven? This does not seem to be covered in Silverman's book. – Ben Linowitz Jan 5 '10 at 22:55
So certainly Ben knows this by now, but future generations: I like the Harvard senior thesis of Tony Varilly-Alvarado as a reference myself. – stankewicz Jun 27 '13 at 20:39
Let $k$ be an algebraically closed field, and let $E/k$ be an elliptic curve. In general, how do we know the structure of $\mathrm{End}(E)$?
We know the following two facts in all cases: (1) considered as an additive group, $\mathrm{End}(E)$ is free abelian on 1, 2 or 4 generators; and (2) $\mathrm{End}(E) \otimes_Z Q$ is a division algebra. The first fact comes from considering homology (more on this momentarily), and the second comes from the theory of the dual isogeny.
• In the case of rank=1, we must have $\mathrm{End}(E)$ an order in $Q$, i.e. $\mathrm{End}(E)=Z$.
• In the case of rank=2, we must have $\mathrm{End}(E)$ an order in a quadratic field $F/Q$. This field must be imaginary, because its norm map is identified with $\lambda \mapsto \lambda \lambda^\vee$, and the latter is positive definite.
• In the case of rank=4, we must have End(E) an order in a quaternion algebra R/Q.
The last case gets ruled out when $\operatorname{char}(k)=0$. We don't see it in the familiar characteristic zero setting, so we think of it as strange, but there really is nothing unnatural about it. The "simple explanation" that you seek is, most bluntly, that it does not get ruled out, since there is no replacement for $H_1(E,Z)$ in positive characteristic.
By the way, here is the reason it gets ruled out in characteristic zero: Without loss of generality by the Lefschetz principle, we may declare that k=C. Assume that $\mathrm{End}(E)$ is an order in $R$. The hard step in proving (1) above is showing that $\mathrm{End}(E)$ acts faithfully on the first homology group $H_1(E,Z)$. Granted this, $\mathrm{End}(E)$ embeds as a free rank four $Z$-submodule of $\mathrm{End}(H_1(E,Z)) = M_2(Z)$. Tensoring with $Q$ we get that $R = M_1(Q)$, and hence $M_1(Q)$ would be a division algebra, which is false.
The reason I mention this argument is that, even though when $\operatorname{char}(k)=p>0$ the argument fails as stated (since one can't make $k=C$ and access $H_1(E,Z)$), one can still modify it to get information about $R$. As a substitute for $H_1(E,Z)$, one instead takes a prime $\ell$ not equal to $p$, and considers the $\ell$-adic Tate module $T_\ell(E) = \varprojlim_n E[\ell^n]$, with transition maps given by multiplication by \ell. (This gadget is a free $Z_\ell$-module of rank 2 whether $\operatorname{char}(k)=0$ or not, and when $k=C$ it is canonically identified with $H_1(E,Z_\ell) = H_1(E,Z) \otimes_Z Z_\ell$, which motivates its use as a substitute.) Considering again the faithfulness of the action of $\mathrm{End}(E)$, we have that $\operatorname{End}(E) \otimes_Z Z_\ell$ embeds into $\mathrm{End}(T_\ell(E)) = M_2(Z_\ell)$, and therefore $R \otimes_Q Q_\ell = M_2(Q_\ell)$. By definition, this means that the quaternion algebra $R$ is "split at $\ell$". Now we invoke a by-product of global class field theory, which is the determination of all quaternion algebras over $Q$. They are parameterized by nonempty finite sets of even cardinality, consisting of prime numbers and possibly the symbol $\infty$. There is a unique quaternion algebra that is split at exactly those primes not occurring in the parameterizing set. Since for all $\ell$ not equal to $p$ we know that $R$ is split at $p$, the only possibility for the set associated to $R$ is $\{p,\infty\}$. Thus we know, on the nose, which quaternion algebra $R = \mathrm{End}(E) \otimes_Z Q$ is.
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This is a theorem of Deuring, 1941. David alluded to this, but Section 5.3 of Silverman's The Arithmetic of Elliptic Curves has a proof that 5 conditions concerning elliptic curves over a characteristic p perfect field are equivalent, and any one of them can be taken as the definition. There are additional definitions of supersingularity, concerning the vanishing of the Hasse invariant (a modular form mod p defined by the eigenvalue of Frobenius acting on the Serre dual to the invariant differential), or line bundles with trivial p-th tensor power being automatically trivial. My favorite definition is that the kernel of multiplication by p is a connected group scheme (necessarily of order p^2).
The l-adic Tate module of a curve is a free Z_l-module of rank 2, so the endomorphism ring of any elliptic curve is a free Z-module of rank 1, 2, or 4, and for rank 2 (resp. 4), analysis of dual isogenies shows that the ring has to be an order in an imaginary quadratic field (resp. a quaternion algebra). If you assume a supersingular curve has endomorphism rank 1 or 2, you can derive a contradiction by combining two facts:
• There are only finitely many isomorphism classes of supersingular curves for a given prime p (in fact, the total number weighted by automorphisms is (p-1)/24). This uses the fact that the j-invariant of a supersingular curve lies in a finite field.
• Given a curve whose endomorphism ring has rank 1 or 2, any isogenous curve has an endomorphism ring with the same fraction field.
The contradiction arises as follows: Take a sequence of elliptic curves as successive images of cyclic l-power isogenies, where l is chosen to be prime in the ring of integers of the fraction field. Two of them will be isomorphic, so you get an endomorphism by a cyclic isogeny. Analysis of degree shows that this endomorphism is equal to an automorphism composed with multiplication by a power of l. However, the two endomorphisms (presumably equal) have nonisomorphic kernels.
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There are a many funny things that can happen to elliptic curves over finite fields. For instance the endomorphism ring can be bigger than in char 0, and there can be no p-torsion (even after extending the field).
It turns out that many of these are equivalent, and we call an elliptic curve satisfying these equivalent properties supersingular. Silverman's AOC has a nice section discussing this.
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I'd like to add a question to this discussion: the endomorphism ring of a supersingular elliptic curve is not just an order in a quaternion algebra, it is a maximal order in such an algebra. Is there a simple explanation for this?
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Tate's isogeny theorem over finite $k$ is valid for all primes: $\mathbb{Z}_{\ell} \otimes {\rm{End}}_k(A)={\rm{End}}_k(A[\ell^{\infty}])$. Increase $k$ so ${\rm{End}}_k(A)={\rm{End}}_ {\overline{k}}(A)$. For $A$ a supersingular elliptic curve, ${\rm{End}}_k(A[\ell^{\infty}])$ then has rank 4 but is the Galois-invariants in the $\overline{k}$-endomorphism algebra of $A[\ell^{\infty}]$. The latter is ${\rm{M}}_2(\mathbb{Z}_{\ell})$ for all $\ell$ (verify using Dieudonne theory for $\ell=p$), so the quotient by its Galois-invariants is finite yet torsion-free! QED Conceptual, yes. Simple...? – Boyarsky Jun 24 '10 at 10:53 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 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": 0.9211126565933228, "perplexity": 250.21561750244976}, "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/1443736678979.28/warc/CC-MAIN-20151001215758-00003-ip-10-137-6-227.ec2.internal.warc.gz"} |
https://eccc.weizmann.ac.il/report/2014/127/ | Under the auspices of the Computational Complexity Foundation (CCF)
REPORTS > DETAIL:
### Paper:
TR14-127 | 11th October 2014 03:02
#### Batch Codes through Dense Graphs without Short Cycles
TR14-127
Authors: Alexandros G. Dimakis, Anna Gal, Ankit Singh Rawat, Zhao Song
Publication: 11th October 2014 04:07
Keywords:
Abstract:
Consider a large database of $n$ data items that need to be stored using $m$ servers.
We study how to encode information so that a large number $k$ of read requests can be performed \textit{in parallel} while the rate remains constant (and ideally approaches one).
This problem is equivalent to the design of multiset Batch Codes introduced by Ishai, Kushilevitz, Ostrovsky and Sahai~\cite{batch}.
We give families of multiset batch codes
with asymptotically optimal rates of the form $1-1/\text{poly}(k)$
and a number of servers $m$ scaling polynomially in the number of read
requests $k$.
An advantage of our batch code constructions over most previously
known multiset batch codes is explicit and deterministic decoding
algorithms and asymptotically optimal fault tolerance.
Our main technical innovation is a graph-theoretic method of designing
multiset batch codes using dense bipartite graphs with no small cycles.
We modify prior graph constructions of dense, high-girth graphs
to obtain our batch code results.
We achieve close to optimal tradeoffs between the parameters
for bipartite graph based batch codes.
ISSN 1433-8092 | Imprint | {"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": 0.6716992855072021, "perplexity": 2703.4670062899386}, "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-2022-05/segments/1642320304471.99/warc/CC-MAIN-20220124023407-20220124053407-00151.warc.gz"} |
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The Classification of Quasithin Groups: I. Structure of Strongly Quasithin $$\mathcal{K}$$-groups
Michael Aschbacher, California Institute of Technology, Pasadena, CA, and Stephen D. Smith, University of Illinois at Chicago, IL
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Mathematical Surveys and Monographs
2004; 477 pp; hardcover
Volume: 111
ISBN-10: 0-8218-3410-X
ISBN-13: 978-0-8218-3410-7
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Order Code: SURV/111
The Classification of Quasithin Groups: II. Main Theorems: The Classification of Simple QTKE-groups - Michael Aschbacher and Stephen D Smith
The Classification of Finite Simple Groups: Groups of Characteristic 2 Type - Michael Aschbacher, Richard Lyons, Stephen D Smith and Ronald Solomon
Around 1980, G. Mason announced the classification of a certain subclass of an important class of finite simple groups known as "quasithin groups". The classification of the finite simple groups depends upon a proof that there are no unexpected groups in this subclass. Unfortunately Mason neither completed nor published his work. In the Main Theorem of this two-part book (Volumes 111 and 112 in the AMS series, Mathematical Surveys and Monographs) the authors provide a proof of a stronger theorem classifying a larger class of groups, which is independent of Mason's arguments. In particular, this allows the authors to close this last remaining gap in the proof of the classification of all finite simple groups.
An important corollary of the Main Theorem provides a bridge to the program of Gorenstein, Lyons, and Solomon (Volume 40 in the AMS series, Mathematical Surveys and Monographs) which seeks to give a new, simplified proof of the classification of the finite simple groups.
Part I (the current volume) contains results which are used in the proof of the Main Theorem. Some of the results are known and fairly general, but their proofs are scattered throughout the literature; others are more specialized and are proved here for the first time.
Part II of the work (Volume 112) contains the proof of the Main Theorem, and the proof of the corollary classifying quasithin groups of even type.
The book is suitable for graduate students and researchers interested in the theory of finite groups.
Graduate students and research mathematicians interested in the theory of finite groups.
Volume I: Structure of strongly quasithin $$\mathcal{K}$$-groups
• Introduction to volume I
• Elementary group theory and the known quasithin groups
• Basic results related to failure of factorization
• Pushing-up in SQTK-groups
• The $$qrc$$-lemma and modules with $$\hat{q}\leq 2$$
• Generation and weak closure
• Weak BN-pairs and amalgams
• Various representation-theoretic lemmas
• Parameters for some modules
• Statements of some quoted results
• A characterization of the Rudvalis group
• Modules for SQTK-groups with $$\hat{q}(G, V) \leq 2$$
Bibliography and index
• Background references quoted (Part 1: also used by GLS)
• Background references quoted (Part 2: used by us but not by GLS)
• Expository references mentioned
• Index | {"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": 0.44049182534217834, "perplexity": 1961.5757903482445}, "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-2014-52/segments/1418802775517.52/warc/CC-MAIN-20141217075255-00165-ip-10-231-17-201.ec2.internal.warc.gz"} |
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# Punnett Squares C Kohn, Waterford WI.
## Presentation on theme: "Punnett Squares C Kohn, Waterford WI."— Presentation transcript:
Punnett Squares C Kohn, Waterford WI
Genetics Genetics is the study of inheritance of genes.
i.e. genetics is how traits are passed down from parents to offspring Every individual offspring inherits at least two copies of every gene – one from the mother and one from the father. Each version of a gene is called an allele. You inherit at one allele from both parents for every gene. Genes can either be dominant or recessive – Dominant genes are always expressed if they are present Recessive genes are only expressed if no dominant genes are present. Source: techcynic.wordpress.com Source: blogography.com
Homozygous vs. Heterozygous
The combination of genes that you have can be described by homozygous or heterozygous. Homozygous means that both of your genes are the same – either both are dominant or both are recessive AA would be Homozygous Dominant (both alleles are dominant) aa would be Homozygous Recessive (both alleles are recessive) Heterozygous means that you have both a dominant and a recessive copy of a gene. Aa would be Heterozygous (one dominant allele, one recessive allele) Source: zazzle.com
Genotype vs. Phenotype Genotype is the term for the genes that an organism has. Phenotype are the physical characteristics created by the combination of genes that an organism has. For example, Mr. Kohn is heterozygous for eye color – his genotype has genes for both blue and brown eyes. However, Mr. Kohn’s phenotype is brown eyes – the blue eye color is not expressed because it is recessive. A A a Aa Aa Aa Aa
Punnett Squares A Punnett Square is a tool used for determining the possible genetic outcomes of the offspring of two parents Punnett Squares are can be used to determine the parents’ or offsprings’ phenotypes and genotypes. Punnett Squares show all of the possible combinations of offspring genotypes that a couple could have. A A a Aa Aa Aa Aa
How would you create a Punnett Square for this family?
5 Steps of Punnett Square Problems
Step 1: Figure out the genotypes of the parents. One is pretty simple – the recessive parent has to have two little letters: aa The other has only two possibilities – AA or Aa So we know that one parent is aa and the other is either Aa or AA.
5 Steps of Punnett Square Problems
Step 2: Figure out all possible offspring that the parents could have. For all possible genotypes, figure out what the offspring would look like in each case. i.e. make a Punnett Square for each possibility.
5 Steps of Punnett Square Problems
Step 3: Create the Punnett Squares A a A A a Aa aa a Aa Aa Aa aa Aa Aa
Step 4: Determine which Punnett Square is accurate
Select the Punnett Square that reflects what we see for offspring below.
5 Steps of Punnett Square Problems
Step 5: Confirm that you are correct. You know that the Punnett Square on the left cannot be right because ½ the offspring are recessive. A a A A a Aa aa a Aa Aa Aa aa Aa Aa
How would you create a Punnett Square for this family?
Step 1: Parent Genotypes
What would be the genotypes of the parents? TPS
Step 2: Determine what offspring are possible from these parents.
What are the possibilities for the offspring? TPS
Step 3: Create Punnett Squares for each possibility
Create Punnett Squares for all parent genotype combo possibilities
Step 4: Determine which Punnett Square is accurate
Select the Punnett Square that reflects what we see for offspring below.
Step 5: Confirm that you are correct.
Be prepared to explain why the other Punnett Square would not work.
Summary Step 1: One parent is homozygous recessive: aa
The other parent is either Aa or AA Step 2: these parents would either have mixed offspring or all dominant-phenotype offspring Step 3: Create Punnett Squares
Summary You know that the Punnett Square on the left is correct because half are the dominant phenotype and half are the recessive phenotype. A a A A a Aa aa a Aa Aa Aa aa Aa Aa
Summary Step 5: Confirm the other Punnett Square is not correct.
You know that the Punnett Square on the right is not correct because all of the offspring would be the dominant phenotype. A a A A a Aa aa a Aa Aa Aa aa Aa Aa Step 5: Confirm the other Punnett Square is not correct.
How would you create a Punnett Square for this family?
Possible Combinations
With simple traits, there are only six possible combinations of parents AA x AA AA x Aa Aa x Aa AA x aa Aa x aa aa x aa Each one will have the same results for offspring ratios each time.
Offspring Ratios If we have only recessive phenotypes, we know that both parents are homozygous recessive – aa x aa If we have half recessive, half dominant phenotypes, we know that one parent is Heterozygous and one parent is Homozygous Recessive – Aa and aa
Offspring Ratios If we have ¼ recessive and ¾ dominant phenotypes, we know that both parents are Heterozygous – Aa and Aa If all offspring are the dominant phenotype, we know that the combination of parents must be one of the following: AA x AA Aa x AA AA x aa Additional combinations would be necessary to determine which it is (except in the last example, where one parent has the recessive phenotype).
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Ads by Google | {"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": 0.9140130281448364, "perplexity": 4704.740385493483}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "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-2018-05/segments/1516084891926.62/warc/CC-MAIN-20180123111826-20180123131826-00062.warc.gz"} |
http://mathhelpforum.com/calculus/50411-lhospital-print.html | # l'hospital
• Sep 24th 2008, 05:25 AM
Linnus
l'hospital
Hey!
How do you do this problem by L'hospital.
$\lim_{x \to \infty} e^x-x^2$
I know you can look at it and say $e^x$ is growing faster than $x^2$.
• Sep 24th 2008, 12:58 PM
mr fantastic
Quote:
Originally Posted by Linnus
Hey!
How do you do this problem by L'hospital.
$\lim_{x \to \infty} e^x-x^2$
I know you can look at it and say $e^x$ is growing faster than $x^2$.
Why use l'Hospital?
Substitute the power series for e^x, simplify and take the limit.
• Sep 24th 2008, 01:38 PM
Linnus
L'hospital because that's what the book wants...
I thought power series was an infinite series...so what would you substitute for e^x?
• Sep 24th 2008, 01:49 PM
mr fantastic
Quote:
Originally Posted by Linnus
L'hospital because that's what the book wants...
I thought power series was an infinite series...so what would you substitute for e^x?
Maclaurin Series -- from Wolfram MathWorld The one for e^x is there somewhere.
I don't care what the book wants, using l'Hopital's rule here is ridiculous.
By the time you figure out how to apply l'Hopital's rule to this problem, you could have solved it three other ways and gone on to answer a dozen other problems.
While I'm warmed up, I'll also say that l'Hopital's rule is the refuge of the lazy and the incompetent nine times out of ten.
• Sep 24th 2008, 01:54 PM
Linnus
I know the series for e^x. I'm just saying since it goes on forever, how do you know when to stop?
Ps: I've figure out another way to solve it by expressing the expressions as ln's.
• Sep 24th 2008, 01:59 PM
mr fantastic
Quote:
Originally Posted by Linnus
I know the series for e^x. I'm just saying since it goes on forever, how do you know when to stop?
[snip]
Since all the terms are positive, I wouldn't have thought this was even an issue when taking the limit x --> +oo ..... Clearly you just need to make sure you use more than the first three terms ....
• Sep 24th 2008, 02:05 PM
Linnus
I'm still a bit confused.
"using more than first 3 terms" is kinda vague. It still doesn't tell me how many terms I should use and why.
Also if we were to change the 2nd term in the original problem to something that is very similar e^x then would the substituting with the series work?
• Sep 24th 2008, 02:18 PM
mr fantastic
Quote:
Originally Posted by Linnus
I'm still a bit confused.
"using more than first 3 terms" is kinda vague. It still doesn't tell me how many terms I should use and why.
Also if we were to change the 2nd term in the original problem to something that is very similar e^x then would the substituting with the series work?
I should have said "at least first three terms".
$e^x = 1 + x + \frac{x^2}{2!} + \frac{x^3}{3!} + \, ....$
What happens if you subtract x^2 from a series using less than three terms ....? | {"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": 7, "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": 0.883729100227356, "perplexity": 1044.1625309814833}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-17/segments/1492917121000.17/warc/CC-MAIN-20170423031201-00320-ip-10-145-167-34.ec2.internal.warc.gz"} |
http://forum.mackichan.com/node/1933 | ## PDF preview problem
Hello to everyone! Thanks a lot for the 6.0.30 version! I need your help with an issue that I have with the PDF preview. I have SW 6, and even though I have no problem editing, the PDF preview doesn't work properly. I have Windows 10 Pro, 64-bit edition. A few months ago I had to format my PC. After reinstalling SW, I couldn't export PDf files properly. Actually, while I am trying to use the PDF preview, the process starts normally and then stops. Do you have any idea of how could this problem be resolves?
### The only guess from the
The only guess from the information in your message is that the TeX Live installation failed. Try installing TeX Live separately from SW. See http://support.mackichan.com/solution/articles/6000046747-tex-live-for-w... for the steps.
### Thanks a lot George for your
Thanks a lot George for your reply! Unfortunately it didn't work... The problem still insists. The .sci file opens normally, but when I demand to pdf preview, the black window is running and when it closes, the window showing the number of passes remains open without any pdf outcome. At the end there appear only the .sci and the .bak file.
### You might try the
You might try the following:
Can you successfully pdf-preview the Std Latex Article shell? If so, then there's something wrong with your document.
If not, start a DOS session (winKey+r, then type in: cmd) issue the command
pdflatex -v
you should see a bunch of information lines; the first line should end with something like (TeX Live 2018 ...). If you don't see this, or get a message saying that pdflatex can't be found, then there's something wrong with the TeXLive installation. One thing to look at is your path. Still in the DOS session, issue the command
path
In the result you should find an entry like
c:\texlive\yyyy\bin\win32
(yyyy is a year, like 2018) which should point to where TeXLive is installed. Make sure that this entry has no spaces in it, since I think that the texlive programs may have problems with spaces.
If none of that helps, then back in SWP6 and with the Standard Latex Article on screen, do File > Export Tex and give the output a name (with extension .tex). Start a DOS session and navigate to the TeXLive bin\win32 folder (using cd). There should be a file called pdflatex.exe there. (dir pdflatex.exe). Now try to compile your saved TeX file:
pdflatex "c:/myfolder/myfile"
where (1) the argument to pdflatex should be in quotes (2) you should omit the .tex extension and (3) you should use / as path separators, not \ as is normal in windows. (If pdflatex starts a nd then throws an error, hit Ctrl+C a couple of times to quit). That should produce a pdf file in bin folder (which you can then delete, along with the aux and log files). Let us know what happens.
### Thank you very much for the
Thank you very much for the advice,pviton! The problem still insists. I cannot pdf-preview Std Latex article. I folowed all the steps that you suggested and all seems to be fine. Namely, the pdflatex in the DOS session is in the correct form. The path appears as the entry that you have written, so the texlive is correctly installed and without spaces. Unfortunately the DOS compilation of the tex file didn't work because it appears an error saying that it cannot find the path of the file, even though I have written the path as advised. Nevertheless I tried to compile the tex file with tex maker using pdflatex in windows environment and it compiled it with no problems. Moreover, the problem with the pdf preview seems to appear only to new sci files. Sci files that I have created a year ago (pre format) are working smoothly. No pdf preview problem appears.
### Let me be sure I understand:
Let me be sure I understand: with your current setup on win10 (after reformatting your hard disk) you CAN pdf-preview sci files created before the re-format, but you CANNOT pdf-preview newly created sci files? If this is so, then I'm out of ideas, but clearly there's a serious problem.
Here's one last thing you could try, just for fun:
In your top-level SWP6 installation folder (the SWP folder, typically under C:\Program Files (x86)\MacKichan\), find the file pdflatex.cmd. Open it in a text editor. On a new line at the end of the file add
pause
then save the file.
Now open SWP6 and open the Standard latex Article (if it isn't already open). Pdf-preview.
What should happen is that a DOS window should open, recording how the pdf-latex compilation goes; but this time it won't automatically close. (At the end of this you'll see the line"Press any key to continue..."). What you should do now is copy the contents of this window to a file. If you know how to do this, skip the next paragraph.
To copy the material: click on the icon at the top-left of the DOS window. In the drop-down menu, select Edit, then Mark. Place the cursor at the bottom-left of the window. Holding down the left mouse button, move the mouse horizontally to the right as far as it will go, then vertically up until everything is highlighted. Release the mouse button. Then again click on the top-left icon. In the drop-down menu, click Edit then Copy. At this point the highlighted material is on the clipboard.
In the DOS window, press any key to close the window. You can now
open a text file and paste in the contents of the clipboard. Save the file, zip it up and post the result here.
Finally, go back to pdflatex.cmd and remove the pause line you entered.
(The point of all this is to see which sci file SWP6 is trying to compile, and which TeXLive installation it's trying to use).
### Thank you very much for your
Thank you very much for your help, pviton! Well, I just realised what is happening, which maybe of some help. At the end, the problem is not in pre and post formating files. Sci files that I have in my Dropbox work perfectly but files that I am working locally cannot pdf previewed. For instance, editing a file that I have in my Dropbox works fine. Copying the same exact file and editing at my desktop doesn't produce a proper pdf file. I don't know if something is happening with the path of the file.Nevertheless, I attach the zip file as you asked.Hopefully, it'll may be of some help!
### If you look at the txt file,
If you look at the txt file, you'll see that we have the lines:
C:\Program Files (x86)\MacKichan>pushd "C:\Users\ganas\OneDrive\ˆ³³Á±Æ±\SWDocs\untitled2_work\tex"
The system cannot find the path specified.
which is why it's not working. I don't know if it's because of OneDrive or because of the non-Roman characters in the path (the bit after OneDrive), but with any luck the tech people at Mackichan may be able to help. (I've never used OneDrive myself: maybe it's a question of permissions?)
The other thing you could do, which I'm reasonably sure would solve the problem, is to change where you store your SWP6 files. You can do this via Tools > Preferences ; and then at the bottom of the General tab.
### It worked! Thanks a lot
It worked! Thanks a lot pviton! It was because of OneDrive.When I installed again the Windows I have accepted, without noticing, that all files are saved by default at OneDrive. Once I changed that and following your instructions for the place where SWP6 files are stored, everything started to work smoothly... | {"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": 0.9537512063980103, "perplexity": 2048.325761910737}, "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/1579250597458.22/warc/CC-MAIN-20200120052454-20200120080454-00346.warc.gz"} |
https://www.quantumdiaries.org/2011/07/22/small-ripple-shakes-a-roomful-of-physicists/ | CERN | Geneva | Switzerland
Small ripple shakes a roomful of physicists
This Friday afternoon, the 750 physicists attending the European Physics Society meeting in Grenoble, France, were pleasantly surprised. The audience was waiting with some anticipation to see the first important set of results from the two large LHC experiments, ATLAS and CMS on the search for the Higgs boson. In fact, for the past two days, results had been shown from both experiments as well as from the Tevatron experiments in various individual channels. But today, the latest combined results from each experiment were shown in public for the first time. Of course, all physicists belonging either to the CMS or ATLAS experiment had had a chance to see their own results in advance, since they had been widely distributed and discussed. A small excess was seen in ATLAS, but nothing particularly convincing. In physicist’s jargon, we refer to these as mildly significant excesses. This was found in one of the Higgs decay channels, namely when the Higgs boson decays into two W bosons. But unbeknown to the ATLAS people, the CMS collaboration was also observing a similar excess that would correspond to a Higgs with the same mass and is seen in the same channel. So taken alone, none of these small ripples were compelling but once they show up in two completely different detectors, it starts being intriguing. Both experiments also reported small excesses for a Higgs to two Z bosons when the Z themselves decay into an electron or muon pair. What might turn out to be the first hint of a much sought after particle also occurred in a mass range not excluded by the Tevatron experiments.
It might not seem like much but this could be the first interesting bite we have in some decades. We are all researchers. This could turn us into “finders”, something very few of us had a chance to live in their career. Hence the lively discussions that followed this session during the coffee break.
But at the same time, we all know it is way too early to get excited. We need more data to be able to say something conclusive, something we do not risk regretting a few months down the line. Today, both experiments showed what they had after analyzing one inverse femtobarn of data (counted in the unit we use to see how much data we have). We already have another 0.4 inverse femtobarn ready to be analyzed. As soon as we can look at them in the coming weeks, we will see if the trend is maintained. The other important missing ingredient at this point is a full fledge combination of both results, taking into account all the common uncertainties. For example, we both use the same simulations to describe our backgrounds. Even though we crosscheck these simulations with real data, there is always a chance a small inaccuracy would trick us both in the same way. The combination team is getting to work on this combination tonight but it will take up weeks to complete this task.
Everybody agrees: We need more data and the combined results. But it is already interesting enough to keep staring in that direction. We might be seeing the caravan appearing in the far horizon. In just a few months, we will see it clearly or discover we all had sand in our eyes…
The CMS collaboration combined results for the Higgs boson search covering a possible Higgs in the region from 110 to 600 GeV.
ATLAS collaboration combined results for the Higgs boson in the low Higgs mass range
Within the red ellipses in the above two figures, one can see a small excess of events that could be the first signs of the presence of a Higgs boson within that mass range. The black lines should lie within the yellow band if there is no Higgs boson. This is what one could say but only with a 95% confidence. The fact that both experiments see a small excess in this region is the reason that makes it more interesting. But only with more data and a very rigorous combination of the two results will we able to say more in the near future. At this point, we can only hope something more definite will come out of this, nothing more!
Another major conference is planned in late August in Mumbai, India. For sure, this combination and hopefully, more new analyzed data will be shown there.
But why do we care? Very simple. As much as we like to say we know about the particles that make up all matter we see around us, to this day, we, physicists, have no clue how fundamental particles like electrons or quarks (that make up all matter) get their mass. As it is, our current theoretical model predicts they are all massless like photons, when we know this is not true. That Higgs boson, if it exists, would provide a mechanism to fix that.
Pauline Gagnon | {"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": 0.8474668860435486, "perplexity": 654.9273757873452}, "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-2022-27/segments/1656103324665.17/warc/CC-MAIN-20220627012807-20220627042807-00368.warc.gz"} |
http://cpanratings.perl.org/user/rrwo | # Reviews by Robert Rothenberg
### Test-Perl-Critic-Progressive (0.03)
This is a great idea, except... when you've changed the code and introduced poly violations, you just get a list of how many violations are in your code. There's nothing to indicate which file or where in a file each violation is.
### CPAN-Mini-FromList (0.02)
There are syntax errors in the minicpan-fromlist script that it installs, mainly due to "use strict" violations.
### Data-Validate-Email (0.04)
Easy to use, works straight out of the tin, etc.
However, it doesn't accept sub-addresses as per RFC 3598. There's been a bug report about that issue since August 2009.
### Video-Xine (0.18)
Missing explicit mention of prerequisites like Params::Validate, List::MoreUtils and X11::FullScreen.
Examples in synopsis are broken: it's not clear where variables come from, or there they are lowercase in one line and uppercase in another.
Even when all that is sorted, and the program runs with no errors, no window is displayed showing the video.
Considering that it's not been updated in almost two years, I've given up on it.
### Math-Numbers (0.000000001)
FYI, "Bluto's Algorithm" is just another term for brute force.
There are several other packages with similar functionality (primality testing, GCD, etc.), but the documentation doesn't explain how this package is different or better than other packages.
### HTML-Strip (1.06)
I've not looked under the hood. But it seems to work well and strip the markup from websites. So I'm satisfied with it.
### Lingua-Identify (0.23)
It's very easy to use, and works out of the box within a few minutes. Not so well for short pieces of text, but enough to be usable.
### Algorithm-MarkovChain (0.06)
I got it working out of the box within a few minutes, which saved me a bit of time coding the same thing. It seems to do what it says in the docs (from a superficial skim, anyway).
It's fairly easy to use, subject to the limitations of the Twitter API. I was able to hack a script that interfaced with it quickly.
My only grumble is that it doesn't support proxies, but I can get by without that.
### Data-Random (0.05)
I haven't looked under the hood, but it (Data::Random::WordList) did what I needed, so I didn't have to write the code.
### Moose (0.68)
I'm ambivalent about it: I love powerful extensions to the language like this, but I cringe when I hear a hard drive churn just to load all of the prerequisite modules.
### String-Urandom (0.04)
Nitpick: data from /dev/urandom isn't "truly random" but data from /dev/random is.
### Term-Shell (0.02)
This module makes it very easy to have a working prototype shell application running within a few minutes.
My only nitpicks are that it expects methods to have names that match their commands (e.g. run_command) rather than using an initialization method, and that the the summary/help/execution functions for each command are separate functions. But these are minor.
There's a few other things I'd like, such as password input methods (esp. one that works with Term::ReadLine::Perl), and better documentation on how/where to save data for my method in a way that won't interfere with the internals of Term::Shell.
### xchar (0.2)
It lets me do some simple queries about top-level windows, but is missing a lot of details (like what desktops the windows are in). And it requires Perl-Tk! The documentation wasn't helpful, either. (But the problem with X11 programming is that there's so many technical details...) I opted to use wmctl from the shell instead.
### Gtk-Perl (0.7009)
No documentation except a README and some POD for the color selection button.
### Convert-Color (0.02)
Graphics::ColorObject already allows for conversions between color spaces.
The name-to-color conversion functionality of Convert::Color::X11 already exists elsewhere on CPAN (and has so for a long time), notably Graphics::ColorNames (which I wrote) as well as Color::Library and Color::Rgb. All of them support X11 color schemes, and the first two of these modules allow plugins to add new schemes, such as for Convert::Color::VGA.
I'm fine with different modules on CPAN doing similar things differently, but I do think it's important for newer modules to refer to existing modules in their documentation, and explain how their modules are different and better suited for some uses.
### Gnome2-GConf (1.044)
I'd like to write a script that can query the subkeys of a given key, and use that information to pass some options to the relevant program.
For the life of my can't figure out how, or even if it's possible with this module (or the GConf libraries that it uses...), because it's so poorly documented. So a neutral '3' stars.
But -1 star, for the lack of tests.
Edit: I've since figured out how to query subkeys, but it involved reading the Gnome library documentation to find that there is the oddly named "get_all_dirs" function to do this, and then reading the source code of one of the XS files in this distribution to find out that it indeed has an undocumented "get_dirs" function that does what I needed.
### CGI-Application-Plugin-Session (1.03)
Seems to work as advertised. I'm unclear if there's a way to use CGI::Simple instead of CGI for CGI::Session, though. And I also wonder if $app->session->param() should just override$app->param().
### perl-ldap (0.39)
I managed to get a simple search query up and running quickly. It's a little bit complex (and I do with there were a few more examples and utility routines to do seemingly simple tasks), but that's more do to myself being new to LDAP.
The object-oriented interface is a bit cumbersome, e.g. $type = (MIME::Types->new)->type(shift). I don't understand the relationship between the MIME::Types and MIME::Type modules: they seem to have the same POD. I just want to be able to get a MIME-Type from an extension, and to get a list of extensions associated with a MIME-Type. A bigger annoyance is that the list is rather small. I wish it could give a "common" extension for MIME-Type (in particular, a 3-character extension), so that I can use it for normalising file names. Moaning aside, I was able to get what I needed from it quickly. Edit: I have since written a module Media::Type::Simple that takes care of my moans... ### Path-Class (0.16) This is an excellent platform-independent layer over File::Spec. One (minor) downside is that it doesn't seem to have a way to update objects. So instead one must do something like$path = $path->parent. (This is fine if you don't want side effects, but then why are you programing in Perl?) Other minor annoyances: (1) a method to extract file extensions (2) untaining. ### self (0.15) Wow. Simple, bareword names for "self" and "args" without filters or dodgy interactions with Perl internals. I'm a believer now.... ### CGI-Application (4.21) Although I've only used this for simple web applications, it's easy to use and you can get up-and-running within an hour after reading the documentation. I also like that it's easily to override default modules to use whatever CGI or templating module that you'd like (e.g. CGI::Simple or Template). My only quibble is that the interface seems slightly cumbersome. ### Net-PingFM (0.3) It's easy to use, and seems to do what it says on the tin, which is to post to ping.fm (and let ping.fm post to other networks for you). This is damn convenient for updating to various blogs and social networks using one interface. Annoyances: it calls the different keys that ping.fm's API requires by different names than ping.fm, though I'm unsure if that's due to API changes by ping.fm or not. (Their own documentation isn't so clear on this.) More annoyances: the online tests use a psychotic amount of dependencies. ### Net-Google-GData (0.01) hanenkamp: look closely at the source code, it's clearly more than a stub. ### Date-Simple (3.02) Another lovely date module for converting between ISO and other formats. Again, it only handles dates, not dates and times. So useless for my needs. ### Date-ISO (1.30) This would be perfect for my needs, except that it only handles dates, note dates and times. So it's useless to me. ### Math-Polygon (1.00) I needed a function to determine if a point is inside a polygon for some elaborate server-side image maps. Perfect for my needs. My only quibble is that the documentation doesn't explain which of the two or three algorithms that it uses. (For some purposes, the method used may not be accurate enough.) ### Image-ExifTool (7.30) It does what it says on the tin: read and write different kinds of meta data from images. And it does this well. It also includes a useful command-line utility for viewing or setting values. ### String-Approx (3.26) I don't see anything wrong with a program dieing on an error. It's just as easy to trap that with eval and respond as it is to check a return code. And if anything, it's *safer* to die if there's an error than to continue as if nothing's wrong. ### Module-Changes (0.05) The Changes file has traditionally been a *human*-readable file. The last thing somebody expects when reading a history file is to see YAML. Yuck! If you want to have a machine-readable change history, use a different filename like "Changes.yml". And generate a human-readable file from that. Additional mini-rant: A machine-readable Changes file won't solve the problems that it's intended to. There's no guarantee that a change marked as "security fix" or "bug fix" won't break your system anyway by introducing new bugs or fixing ones that you thought were features, nor is there a guarantee that the author tagged changes correctly. And if a security fix is mixed in with API changes, then you can't separate the two. If you're so concerned about updates breaking your system, then you're a fool to rely on automated tools in Perl. Read the Changes file, look at version diffs, test on a different server before upgrading. (This is what a responsible sysadmin should do anyway.) Or better yet, don't upgrade if you don't have to. ### ShipIt-Bundle (0.02) Nitpick: Should be called Bundle::ShipIt. (If nothing else, automated testing tools can ignore it.) ### Acme-Tiny (0.4) 5 stars for p***ing people off. It's an Acme module, afterall. And an excellent example of one, too. If you don't like these modules, just don't include the namespace in your personal mirrors. ### Carp-Always (0.09) This module hasn't really explained why it is better than carp: it traps the DIE and WARN handlers so that the carp "longmess" stack traces are always used. That should be made clearer. Which is nice, but... The docs state that the current version doesn't play well with other modules that change the die/warn handlers. This is something that can be fixed easily. (It's done in Win32::EventLog::Carp -- which I wrote -- for instance.) I'm not sure that I like warnings to always be verbose, though. ### Date-Tiny (1.03) The rationale for this tiny date module is that since it's hard to get date manipulation right, we won't do any date manipulation at all. This limits the usability of this package. Maybe some simple manipulation functions (as long as their limits were documented) would increase the rating. (These could be auto-loaded so as to keep the core "tiny".) That said, once I've parsed a date into year, month and day, I don't need to manipulate it much. (One can use stringified dates to compare them.) So I wouldn't call it useless at all. It's just that the OO interface might be too much overhead for something simple. It does fill a need though: DateTime takes a long time to load and can be like using a sports car for local errands. ### Tie-Hash-Sorted (0.10) I've not made use of any special features, but when you need a hash that is always sorted when you iterate over the keys, it's simple matter of tying the hash and forgetting about it. ### Net-ARP (1.0.2) The function for looking up the MAC address of a device by an IP address just doesn't work. You are better off using a system call to arping on a system that supports it. ### Tie-Sub (0.05) Tying a subroutine to a hash is a simple thing to implement, but it is nice to have it already done. It works just as it says. Only thing lacking is the use of the STORE method to pass additional values to the subroutine. However, I don't need that feature, and I can understand why it would make the program semantics weird (but then again, the joy of Perl is in making things weird). ### Text-Aspell (0.09) It has a nice OO interface, seems well-documented, and seems to do what it says very well. ### LaTeX-Parser (0.01) Last updated in 2000 as a 0.01 release. Poorly documented. There's no explanation of what the format of the parsed content is. So I won't go near it. ### LaTeX-TOM (0.8) This seems pretty easy to use, although I had to re-read the documentation to understand how to use it. The docs lack sample code. It lacks tests. It needs at least some tests! It doesn't try to decode accented characters or symbols, which is great because I can throw them into TeX::Encode if I need to. My gripes are that the plainText method assumes it's given a full document (inside document environment anyway) and that it can't do serial parsing (e.g. I feed it a line, get partially parsed output, feed another line, etc.). But there are easy workarounds for this. A serious gripe is that it doesn't recognize some forms of math mode, using$..$or $$..$$. That will require me to write a workaround. Grr. I find the distinction of types between Trees and Nodes to be unnecessary. It also uses a hack to guess the arguments for a command (assumes argument is not separated by whitespace form command and that groups following commands are arguments) rather than using known or common commands with set numbers of arguments. Still, I've got some high expectations for this. UPDATE: it tries to be too smart in it's parsing, and so cannot parse commands for special packages or custom commands. I wanted to write a script that converts markup for one package into another. May as well write my own parser. ### Lingua-Ispell (0.07) Grr. No tests, and it failed because it wanted to run /usr/local/bin/ispell rather than /usr/bin/ispell. ### Net-Dict (2.07) Looks like a bit of fun to play with, but it's got some minor problems: The dict script requires AppConfig::Std, but the Makefile doesn't require it during install. It fails some tests. Not sure why, if it's because the test.dict.org server had changed, or if there's a genuine problem with the module. ### HTTP-Recorder (0.05) No comment about this specific distribution, but about specific reviews: * Usage advice, tips and tricks, etc. belong in cpanforum.com or annocpan.org * Bug reports belong in rt.cpan.org If there are quirks that make it hard to use, or bugs, then they are certainly worth mentioning in the review. But the gorey details belong in appropriate forums, not reviews. --Rob (at the risk of having this review marked useless) ### Time-Fuzzy (0.30) For starters, in the description, "Nobody will ever say ''it's 11:57''. People just say ''it's noon''." Well, no. People do say ''it's 11:57''. They also say "it's almost noon", "it's about noon", or "it's just after noon", etc. I'm not sure I agree with how time is divided up: the source code says hours 0-4 are night, and 5-7 are "early morning", for instance. Hours 11-13 are "noon", but I'd hardly call 11:01 or 13:59 "noon". Those distinctions are rather subjective. People in the English-speaking world have different ways of describing time. In some parts of the world, people will say "half past one", others will say "half one", or "bottom of one". Or they'll say "quarter of one" or "fifteen minutes before" in place of "quarter to one". My (albeit limited) experience is that people are so used to regional dialects with respect to time that "quarter to one" is not always universally understood as "12:45". It's an interesting idea for a module, but the problem it's meant to solve has a lot more complexity than it can handle. Nitpick: it belongs in the Lingua::EN namespace, since it converts time to a natural language string (English). ### Math (0.525) Aside from defining functions that already exist in core Perl (why?), this includes other Math::* packages for representing and manipulating colours, vectors (why separate modules for 2-, 3-, and 4-d vectors?) and image sizes. So it probably belongs in the Image or Graphics namespaces. However, I'm unsure what this package adds in terms of functionality to anything. The SEE ALSO sections generally refer to other packages in the that distribution, than to anything else on CPAN. It makes a reference to asking the author about adding holidays to Date::Holidays::AT which is by a different author. Odd. ### Acme-Placeholder (0.04) While I appreciate a good sense of humour, this is just counter-productive, since it singles out the ills of a specific author. In a year's time, most will forget wha tthe joke was about, and it will just grab more namespace. ### File-Recycle (v0.0.1) Two namespace grabs by the same author, File::Trash and File::Recycle, for basically the same functionality. Why?!? (As someone who bothered to bring up the topic on the module authors list and reserve a namespace for a module with similar functionality, this is irksome.) ### File-Trash (v0.0.1) Two namespace grabs by the same author, File::Trash and File::Recycle, for basically the same functionality. Why?!? (As someone who bothered to bring up the topic on the module authors list and reserve a namespace for a module with similar functionality, this is irksome.) ### XML-Tiny (1.03) The documentation is pretty explicit that it supports a subset of XML, and it's pretty explicit as to what that subset is. Presumably for cases where you are in control of the XML, this will do fine. That said, I usually seem to be working on systems that already have some other XML parsing module installed, so I've not rarely had need for a lightweight alternative. So I've never had to the chance to use it for anything serious. ### PerlBuildSystem (0.43.290) The README and license.txt are POD, not plain text. The license is absurd: "You are forbiden [sic] to use PBS if one of the following applies to you: * You belong to any armed group (inclusive any nation's army). * You work for (or are) an armement [sic] designer, constructor, producer, or saler [sic]. * You, are part or, work for an entity that directely [sic] produces work or goods for any of the above." Typos aside, this license excludes most major corporations (including software corporations) which have some connection to the arms industry, citizens of countries with universal military service requirements, people who work for any national government, and employees or students (who are a "part of") of a major university (as most have grants for some kind of arms research). ### XML-Parser (2.34) I do with there were examples in the documentation (*), but I was able to write a simple parser to do what I needed in about 15 minutes. The Tree, Subs and Object modules look like they might make my life easier by putting everything into hashes, objects, etc, but they are so negligibly documented that it's just easier to write a Parser as I know what it should do, versus hacking with dumps of data structures to interpret what is going on. (*) at least as viewed in search.cpan.org, I didn't poke around very much or look closely at the samples subdirectory in the distro (shouldn't it be called "eg"?) ### UNIVERSAL-can (1.12) I don't like packages which do things in the UNIVERSAL namespace much, but I'm not going to refuse to use a package just because the *tests* (not the running module itself) use it. In the case of Catalyst, the dependency on Test::MockObject has been removed in the latest version. ### Regexp-Common (2.120) I needed a handy Regexp to strip some comments from a JavaScript program and found them here. Works great. My only concern (without looking at the module internals) is that I've got a lot of unused Regexp's for other comment types sitting in memory that I just don't need (40+ languages). Alas, I tried using it for matching URIs and was dissatisfied. I can understand that it doesn't recognize unusual URI types, such as doi or svn, but it doesn't recognize https or ftps. Yuck. ### EOL (v0.0.2) No mention of existing modules with similar functionality: Text::FixEOL, PerlIO::eol, Whitespace. As usual, namespace nit: toplevel EOL is a bad name. Why not in the Text::* namespace? ### DateTime-Natural-Parse (0.04) This is not well documented, which is an important issue since parsing is a difficult problem. Meaning is contextual. If I say "this morning", what time does it give? Looking at the source, it assumes 8am. But what if I meant a different time? If I say "this morning" at 1am, do I mean the morning of the day before, or the moorning which occurs later? Or do I mean the current time (which is still technically morning)? How does it handle unknown words? If I say "this coming Friday" or vague phrases like "in a couple of days"? Can I specify holidays? If so, words like "sabbath", "Easter", "Eid", or "Thanksgiving" are dependent on the religion, region, or country of the user. There are no comparisons with Date::Manip, which has some similar functionality. (My own experience using Date::Manip in an application to give users flexibility in how they entered dates and times is that they had so many bizarre ways of specifying the time that it turned out to be easier for the developers and users to require a standard input format, which was eventually replaced with a drop-down menu for choosing the date and time.) The idea behind it is nifty (in a toy kind of way), but it's strewn with pitfalls. From past experience with somehting similar, I'd not use this in a production environment. And the obligatory namespace nitpick: should be in the Lingua::EN namespace, or at least indicate that it's English-language-specific. ### W3C-LinkChecker (4.3) It works well, and even makes recommendations about updating links which point to referring websites. Only some minor nitpicking: * For links to password-protected pages, it says "The link is not public. You'd better specify it." It's not clear from the documentation how one specifies for the robot that the site is password protected. * It doesn't install through the cpan shell, so must be manually downloaded and installed. ### Math-MultiplicationTable (0.01) It generates a multiplication table, as a printable string. No options to control layout or format, etc. This has little use outside of an exercise from a How to Program 101 class. What is the point of uploading something like this to CPAN? ### File-Copy-Reliable (0.30) It just compares the sizes of the source and destination files. It's better than no checks, but I'd hardly call that reliable. Why not options to add various degrees of reliability checks, such as comparing the source and destination files, or comparing checksums of the files? One of the stated uses is for copying over networks, where even minimal checks are needed. The flaw may be in using File::Copy as a base, rather than something else which does validation checks for each block copied, or that is network aware. How does this compare to using scp or rsync? ### Text-Bastardize (0.08) Various methods which munge text strings, things like rot13, pig latin, or "censoring" words by changing vowels to asterisks. Mostly novelty use, so it should be in the Acme namespace. ### String-CRC32 (1.4) It's simple (just provides a crc32 function), and seems to do what the docs say. No bells and whistles like OO interfaces so that one can initialize it, throw arbitrary chunks of data into it, and finalise it when ready. But that's not needed for most cases. I do wish the package style would be updated to modern standards, but the module is still relatively up-to-date and can still be installed using the cpan tool. ### Module-Inspector (0.03) This version appears fairly well documented, except that the TODO says "implement most of the functionality". What functionality is missing? Having written code which examines distributions to extract information before, I understand the need for this module. There's not many tests on it, but I hope that it turns out to be portable (e.g. runs on Windows , Macs and various Nix flavors). I look forward to making use of it when (if?) I take up some old CPAN-related projects again. ### WWW-AA (0.01) It's got unedited stub documentation created by h2xs, so it looks like a namespace grab. But there's some code that does some kind of encoding/decoding, along with one-line comments in Japanese (I'm guessing Japanese by the author's name). What's it for? What does it have to do with the web? ### Crypt-Lite (0.82.06) This package worthless. The author falsely claims that multiple encryption increases security: that's snake oil. It seems to be throwing in data generated by rand(). Not very secure at all. Installation of other crypto packages with complex dependencies is a false reason for promoting this package: it's eas yto install many of them, even on a Windows machine with no compiler. Whether other packages have more complicated interfaces is no reason to provide a simple interface with a junk algorithm. ### TeX-Encode (0.6) It's fairly easy to use, but the job it does it less than satisfactory when decoding TeX. Some of the translations are wrong: {\L} is translated to "L" instead of L-stroke ("Å"). It cannot distinguish between TeX markup, such as \emph{emphasized text} and unrecognized character codes, but it does remove the initial backslash. If I have to separately parse the text to handle other markup, I may as well implement a character decoder there too. So this module is of little use for decoding. ### Tk (804.027) This review is based on using Tk for a project two years ago. The reason the project used Tk over Wx is that it was the only thing that ran on our Windows machines. (We wanted to use something that was OS-independent, but most clients had Windows.) The calling style is very un-Perlish. It's not even C-ish. It's Tcl-ish. Preceding argument names with dashes is a serious annoyance, especially when you are dynamically generating widgets from code templates. It's a struggle to keep code form looking like unreadable spaghetti code. Generating widgets form code templates (that is, subroutines which generate more subroutines) was painful. Argument names were not intuitive. The documentation was poor, and required consultation with the Mastering Perl/Tk book and a lot of searching on the Internet for examples. Some settings just never worked. It took a lot of experimentation to learn how to use the different layout managers so that the windows were aesthetically pleasing. The code seemed kluge-fulled. Even then, the actual application looked like a no-frills X-windows application, rather than a native Windows (or Mac, or Gnome) application. ### Text-BibTeX (0.36) I've used this for a project to generate BibTeX entries from a list of publications. It seems to work quite well. But it doesn't seem to do any escaping of characters (perhaps I need to RT*M a bit more?). I also needed to convert the author list from comma-separated string to "and" separated. Not a big deal, but this is probably a common task that a module with utility functions would be helpful. I also wish there was a "Simple" interface for generating "regular" BibTeX entries based on a hash. Still, it saved me from writing code to generate or parse BibTeX. ### cwd (HASH(0x9fd52b0)) Very bad: there is already a "Cwd" module, which has been part of the core since Perl 5.000. The name "cwd" will cause problems on systems with case-insensitive file names. Not so good either: no version number, and a default README file do not give me confidence in the module's quality. It's not clear why this should be a pragma. Pragmas are for modules which alter Perl's functionality (even if in a limited scope). All this does is allow one to temporarily change the directory that code is running in. How this is a (better) alternatrive to using File::pushd or Sys::pushd (let alone Cwd or File::chdir)? ### Bundle-PBib (2.08.01) This is a Bundle distribution which contains several modules! Bundles are not supposed to contain modules, but are meta-packages. The Bundle namespace is ignored by most automated testing software. CPAN and CPANPLUS shells have problems with this package because of that. ### Acme-MetaSyntactic (0.74) This is useful for generating a sequence of nonsense variables like foo, bar, baz etc. But now it's overkill--even for an Acme module. The package has dozens of "themes" which probably belong in separate plugin packages. ### Prima (1.20) Minor nitpicking question: why does this package have a separate INI-file module, when there are already several others on CPAN? ### Snail-CSV (0.07) This package doesn't compare itself with other CSV packages such as Class::CSV, Tie::Handle::CSV, or DBD::CSV (among others). What does it do that others do not? The name "Snail" in it does not imply confidence in its efficiency. ### File-Path-Expand (1.02) I hate these "this module is misnamed" reviews, but alas... it's a wrapper for User::pwent that checks for$HOME beforehand. I'm not sure how portable it is: it probably should make use of File::HomeDir instead.
(I would point out that Cwd's "abs_path" does the same thing, but it's buggy: works for "~user" but not "~".)
### Module-Signature (0.53)
After some ongoing bad experiences with this module, I really needed to edit my review and lower the rating.
This *should* be an important tool for verifying that distributions aren't tampered with. But the security value is limited, especially in an automated or partially-automated (CPANPLUS) environment.
It only checks that a signature is good, but does nothing to enforce that the key belongs to the author associated with the module, nor is there an option for it to enfore that the key used to sign the distribution is in a web of trust.
It has problems with end-of-line conventions when files are shared between Windows and Unix. So signatures sometimes fail for text files when checked on platforms with different end-of-line conventions. So builds fail...
It also inherits problems from GnuPG. GnuPG is unable to request subkeys from keyservers. But that's ok since some keyservers mangle subkeys anyway. But Module::Signature will let you sign a module with a subkey. Ooops.
So in order for my modules to be useful to a (important) segment of users, then I have to disable module signatures in the distribution.
It's rather sad, but a lot of work has been put into an illusion of security.
### Spy (0.00_02)
Minimal documentation for the B:: module, and none for the Spy::* modules. What does it do? How does one use it?
### Attribute-Handlers (0.78)
This is an easy-to-use interface for defining custom attributes. But there are several annoyances:
The documentation is not as clear as it could be. For instance, it's not obvious how to "export" attributes so that they can be used in another package. I've had to look at code in CPAN to see that the handler should be called "UNIVERSAL::Name" instead of "Name". I hate putting things in the universal namespace, and indeed that leads to conflicts. (Attribute::Handlers and Class::Std are incompatible, for instance...)
The documentation does not make it clear that the distinction between running the handler when the attribute is defined, versus a handler that mediates access to the object (as with a tied interface). Parts of the documentation imply the latter, others imply the former.
If I create an attribute name in all lowercase, I get a warning about how it might become a future reserved name in Perl. Ok, but I don't care and want to turn that warning off, specifically. How?
### Variable-Strongly-Typed (v1.1.0)
Unlike Attribute::Types, you can assign types to subroutines.
But the name is inappropriate: it checks the type of the return value of the subroutine, rather than wanted value. "Strongly typed" implies compile-time checks and a degree of type safety, so it would disallow things like
$len = @list; I tried to show a nice counterexample, sub foo :TYPE('ARRAY') { return (1..10); }$bar = foo();
Well, this doesn't work, but not for the reason you would expect. Type 'ARRAY' is an array reference, not an array. It's documented, but it's not intuitive.
It would be nice to differentiate between arrays/lists and references to them.
### File-HomeDir (0.57)
I really like the idea of this module (a platform-independent means of identifying the home directory), and don't understand why this functionality wasn't added to something like File::Spec.
This new version supposedly fixes the Windows bugs from v0.06, so there should be no reason for people to roll their own home directory code. (I no longer use Windows, so I cannot test the quirks in this.)
I particularly like how the newer version adds support for "my_documents" type folders. I hope to see future versions interoperate with File::Temp and File::Basedir.
### DBD-CSV (0.22)
I've only needed this for very simple queries on single tables, but it works quite well, despite the limitations of CSV (no types specified for fields).
It's particularly useful for adapting to any delimited text file.
My only gripe is that it doesn't automatically detect the end-of-line conventions. It's particularly messy when you have a CSV file shared by people using different operating systems.
### Rcs (1.05)
I was looking for something to extract the latest version of a file from the "rcsfiles" inside a local CVS repository.
The interface is very simple, though RCS command options are passed directly to the methods, rather than using perlish options which do the magic for you.
The package works and does what I need, quite simply and quickly.
### Rcs-Parser (0.02)
All I need is a simple utility to extract the latest version of a file from an RCS ",v" file.
This module doesn't seem to work. But I cannot tell if it's due to poor documentation or a bug in the system.
There's very little example code. What's there is wrong (it says to use "new RCS" instead of "new Rcs::Parser"). It seems to parse files created by "rcs", but runs into errors related to log entries and so cannot extract a version.
It chokes on files created by CVS.
The documentation does warn that it's alpha quality, but it's nearly useless.
### Class-Date-ISO (0.01)
It adds an "iso" method to Class::Date which returns an ISO-style string.
But that ability is already in Class::Date. On just needs to set the desired format and use the string method.
I'm rather iffy on the means it uses to add the method to Clas::Date.Rather than inherit the class it specifies a new Class::Date package with the added method. (Admittedly I've never seen this style of adding a method to a class, but it seems dodgy to me.)
### Class-Entity (0.1)
No MANIFEST, no README. A typo in the POD says it's documentation for "Clas::Entity".
Why does the name Class::Entity have to do with "Object interface for relational databases"?
tar files come in two flavors: GNUTAR and POSIX. WinZip only supports the former. Lack of WinZip support is no reason to criticize the package.
### DateTime (0.34)
This module does more than you'll ever need for Date-time calculations and handling. I'd call it the de facto standard, were it not for the load time. Adding a "use DateTime" statement to a script adds a quarter-second to the start-up time on my machine (admittedly it's an old machine, but it's hardly a klunker). So I'm hesitant to use it for simple date-time manipulations.
I'm also curious why there's no constructor to take the stringified date/time and reinstantiate it as a DateTime object. (Or if there is, it's not documented.) If I have to use an additional module or write my own parser, then it's less useful. Date::Calc does what I need and loads significantly faster.
### File-BaseDir (0.02)
I've not given it a thorough evaluation, but it seems useful if you need the Freedesktop.org base directories. My only nitpick is that the module should have Freedesktop in the name, since it's not useful for anything else.
### Sys-Filesystem (1.18)
The documentation is wrong: it gives an error when you give the "regular" option to the filesystems() method.
The options are disjunctive instead of conjunctive: I want a list of mounted (and) regular filesystems, but I get a list of filesystems that are either mounted or regular. Once I have a list of filesystems, there's no way to query each object in the list to see if it's mounted or regular.
So it's of limited usage.
### List-MoreUtils (0.18)
These are useful utilities, but I have a problem with the names of some of the functions.
"true" and "false" return counts of the number of true or false return values in code blocks operating on the lists. But reading code which uses them is confusing. One would expect them to return truth values, not numbers. A more intuitive name would be "count". (And one only needs a count-true method; false is easy to implement from that.)
One could nitpick about other function names, but they're not as critical.
### Text-Trim (1.00)
It's one of those things that you constantly find yourself writing, so why not put it in a module. I might still insist that since it's only a regex, it's not worth it as a module (especially a non-core module). But it supports void context and trimming entire lists. It also can differentiate between leading and trailing whitespace.
Regexp::Common has a whitespace module, but cannot differentiate leading and trailing whitespace.
### Clone (0.18)
This module is almost great. I've implemented some classes and needed to add "cloning" ability. Rather than write complicated recursive cloning functions (which I started doing....) I found Clone. It was as simple as adding
use Clone 'clone'
to the code to add a clone method to the class, and it seems to work with no problems.
But minus one star because it doesn't make use of any serialization hooks like Storable does. So for certain kinds of objects, clone just doesn't work. Minus another star because the documentation does not reflect this, aside from a recommendation to use Storable's dclone for slower but more reliable cloning.
Since Storable is a core module now, I'd just assume use that instead.
### Data-HexDump (0.02)
I needed a quick and dirty way to show a hexdump of some binary data in Perl. This module exported a HexDump function that did just what was expected: return a string of lines of hexidecimal numbers and ASCII characters from the data. Which allowed me to quickly verify whether some software was working or not.
Only downside is that the tests gave a lot of warnings about pack formats.
### podlators (2.0.3)
I was using Pod::PlainText to convert Pod to text. Alas, it didn't support the head3 and head4 tags. Pod::Text does. It's also a drop-in replacement (in part because Pod::PlainText was branched off from it), although it's since been updated. I'm happy with it.
### Config-INI-Simple (0.01)
Wow! Yet another INI file module, only seven days after Config::Mini released to CPAN, and yet no mention of that or of Config::IniFile, Config::Tiny, and Config::IniHash.
Ok, but *why* use this module as opposed to other modules? What does this module provide that others do not?
### Config-Mini (0.01)
Yet another module to handle INI files.
Ok, so maybe 'there is more than one way to do it' but the documentation should at least compare it with Config::IniFile, Config::Tiny, and Config::IniHash.
### WWW-Mechanize (1.16)
This looks like an excellent package, but I've never been able to get a version which passed the tests on the Windows or Linux boxes I've used. So I'll have to disagree with the comments that this should be a replacement for LWP::UserAgent. The fact that this package often (but not always) fails tests on certain platforms makes me reticent to require it for an application.
### Module-Build (0.2611)
After using it for years, I'm still very happy with Module::Build.
It is way-better than MakeMaker. It's easier to use, allows one to specify more complex requirements and recommendations than MakeMaker allows, but it has backwards compatability so it can generate Makefile.PL as well as Build.PL.
I strongly recommend using this and as a replacement for MakeMaker.
One important and subtle hitch: it does not handle auto-splitting automatically, and the docs indicate that the autosplitting interface may change. So if you've installed an earlier version of your module (using older Makefile), it will pass tests because autoloading methods are already available, but it will fail CPAN testers.
Another nit (and the reason I've updated my review): one does need to read the docs section "Alternatives to PREFIX" before complaining about it: <search.cpan.org/dist/Module-Build/lib...;
### UNIVERSAL-clone (0.01)
I'll chime in as well, but for different reasons: Clone (and Storable) cannot handle all objects, particularly onjects which do some low-level memory allocation in C.
It's not clear for certain types of objects what a clone is: should a clone have the exact internal data structure (an issue for non-deterministic algorithms), should the response times to queries be the same, or should it merely have the same data?
Bad things will happen if you rely on this to actually clone something.
I hate to give a module a "lousy namespace" review, but...
That said, despite the tests of Term::Readpassword failing in reports on Win32 machines, I recall getting it to work on Win32 when I used windows. I'm not 100% sure of this and no longer use Windows, but I'm skeptical of the need for a separate module just for Windows. I am sure that there already are modules which allow one to read from the console without echoing the keystrokes, even if it isn't Term::ReadPassword.
### Date-Holidays (0.05)
I think the idea behind a Date::Holidays interface is flawed:
1. Wouldn't it be better to have a wrapper that reads arbitrary iCal files (which could have anything from holidays to events for specific institutions)? There are already many published calendars which are used by calendar applications ranging from Mozilla Calendar, Mac iCalendar, KOrganizer, etc. Better to have the module use that information (which might already be available on a machine) than duplicate (and inaccurate) information?
2. Why are holidays just delineated by countries? Don't various states and provinces have their own local holidays? Don't some localities (e.g. Scottish councils) have their own holidays? Don't some institutions (e.g. schools) have their own holidays that that they honor? And what about religious holidays?
3. Differentiate holidays from noteworthy events. Daylight savings time is a noteworthy national event, but is hardly a holiday. If one boths to put this information in a module usable by a computer, then there should be meta-information about this event that the computer can use (e.g. to know whether to expect more or less activity on the network).
### Algorithm-Step (0.02)
There seems to be no documentation in the module. Instead it's included in a separate script. So I'm not sure what sort of new thing this module actually does.
From the synopsis it appears to allow one to add "step" statements in various locations of an algorithm, so that one can watch the various steps. There are various debugging and log packages that can do the same, but can be "turned off" when not needed.
Steps are also numbered, but that may not be applicable to certain algorithms which do not have sequential steps.
It also gives some kind of statistic metric for each step, but does
not say what the number means.
And the information is simply printed. Better that it be logged to some kind of file for processing later. Perhaps another reason that the logging system like Log::Dispatch or various debugging and benchmarking tools would make a better base for this.
### SuperLog (HASH(0x910289c))
Top-level namespace with no version and no POD. Very bad.
### Logger (HASH(0x9103a00))
Top-level namespace with no version and no POD. Very bad.
### Log (HASH(0xa3ae960))
Top-level namespace with no version and no POD. Very bad.
### Data-PowerSet (0.01)
No rating, but just a note that there already exists a List::PowerSet module. How does this differ?
### Perl-Review (0.04)
This sounds like an excellent module, but I have a nitpick with the namespace: it sounds like it has something to do with the managzine The Perl Review.
Perhaps it should be called Devel::Review?
### Bundle-Ovid (1.01)
I'm not sure that a Bundle module that lists personal preferences of what a fresh installation of Perl should have belongs on CPAN. Frankly it's of little use to anyone but Ovid.
It makes little sense for me or anyone else to request changes since those reflect our preferences to what should be installed, not Ovid's.
It makes little sense for me (or I think anything else) to have out own Bundle::CPANID module since what extra modules are installed depends on the machine and what it's used for.
### Log-Delta (0.03)
This module inserts fine-resolution (Time::HiRes) timestamps into log messages, but otherwise doesn't provide the capability of other logging packages for log levels or multiple destinations, such as Log::Dispatch.
Indeed, it's easy to do the same thing with Log::Dispatch by using a callback.
Also: The PREREQS in he Makefile.PL aren't properly set. -1 star.
### GMail-Checker (1.04)
Since GMail gives POP access, I'm not sure if this module is needed.
### Mail-Webmail-Gmail (1.04)
Since GMail gives POP access, I'm not sure if this module is needed.
### WWW-Scraper-Gmail (0.09)
Since GMail gives POP access, I'm not sure if this module is needed.
### WWW-GMail (0.06)
Since GMail gives POP access, I'm not sure if this module is needed.
### CaptureLog (0.03)
I can't tell what this does. There seems to be only the .pm file in the distro, with no ChangeLog, README, etc. The documentation is garbled from bad POD formatting, and perhaps an unintentional global search/replace.
The module is named Log::SimpleLog::CaptureLog, but the distro is named CaptureLog.
There's no Makefile.PL or Build.PL, or tests either!
### File-Slurp (9999.09)
It just doesn't work all of the time. I can slurp one file, but then the second file it claims doesn't exist or it is unable to read anything from it.
I don't have the time to diagnose why it doesn't work. It was faster to write my own few lines which were adequate for what I needed.
### HTML-Perlinfo (1.00)
It's a lot of work just to output the Perl Config{}, environment, and server information to a web page. (There are several modules it uses for this.) One just doesn't need a module for this.
The question is, why?
The only use I can think of for this module is when one is given access to a web server that can run CGI scripts and needs to determine some information about the server and Perl installation. But that requires this module to be installed... if you can get the SysAdmin to install this module and its prerequisites, then why can't she answer your questions about the server? (And if she won't answer your questions adequately enough, why would she bother installing this module for you?)
### Devel-Messenger (0.01)
This does not do anything more than Log::Dispatch, and if anything is less general in that it's intended for adding debugging messages rather than logging events into various places.
### Finance-Currency-Convert-Yahoo (0.045)
It works well enough for my purposes, although it does not use a very efficient method of obtaining the information. (It parses an HTML page rather than downloadinhg the CSV.)
One problem is that it does not list the prerequisite modules in the Makefile.PL or META.yml.
### App-HWD (0.06)
An abstract like "The great new App::HWD!" tells me nothing about what the module does.
It's bad enough when the first release on CPAN has a description like that. But several versions later?
### Win32-File-Summary (1.00)
Why does this module include Archive::Tar and IO::Zlib rather than list them as prereqs? The documentation for the included modues seems to be missing the copyright messages as well... are these the same as the CPAN Archive::Tar or a modified version?
The documentation for Win32::File::Summary is poorly layed out, it seems as if the author does not understand that POD parsers do the work of indenting and wrapping paragraphs etc.
### Toolkit (0.0.2)
Toolkit lets you save typing or cut/paste by saying "use Toolkit" instead of "use strict; use warnings; use Acme::Whatever" and whatever other favorite modules you like to use all of the time.
It's a really neat idea. It is also a really bad idea.
It saves keystrokes. But the script or module ceases to be portable to another machine (let alone another OS), and the code is less self-documenting as to what modules it uses.
There's no tool to modify a script or module to insert the used modules in place of "use Toolkit", should one desire to see what's being used.
However, I can see cases where this would be useful: if someone has a large stock of standard modules to always be used.
I think it would be better to have some kind of "profile" configuration file that lists modules used (using "use", "no" or "require"). One could dump the module, or updated versions of Module::Build or ExtUtils::MakeMaker could include the profile file with a distribution, etc.
### Carp-Indeed (0.01)
This is meant to be used in the command line:
perl -MCarp::Indeed script.pl
but then one can use
perl -MCarp::verbose script.pl
for largely the same effect (the latter being part of the Core, however).
It redefines die and warn functions and forces their export but doesn't override the signal handlers, so many errors and warnings won't be caught by this. (The docs say it does muss around with the signal handlers, but it doesn't.) So it's only useful when a program calls die/warn/croak/carp.
The documentation has various rants about the meanings of words like "carp", "confess", "cluck", etc. (I suspect the author misunderstands the humor in that naming scheme) and some things about Acme::JavaTrace that make little sense.
### Algorithm-Diff (1.1901)
I'm trying to do a diff of two text files with about 40,000 lines each.
GNU diffutils finds 115 chunks but Algorithm::Diff finds one great big mega chunk.
### Filter-Include (1.5)
When I saw this module, I asked "why did somebody write a module that uses Filter::Simple, Module::Locate and Scalar::Util, all to achive what you can do with core Perl using a require or do statement?"
Filter::Include includes the text of the file before it is compiled. The require or do statements parse the file (and do so at runtime). So in theory there's nothing wrong with that, provided you know the difference. The documentation does not explain it.
Instead it links to a thread on the PerlMonks.org web site, which if one reads, it seems that the thread was started by a novice who seems not to have understood what he was doing.
The documentation needs to explain the difference between what the module does, and using require or do (and using them in BEGIN blocks for compile-time inclusion).
In the end, I'm not really sure there's a need for this module so much as the illusion of a need by users who don't realize there's a better way. (Yes, yes, there's more than one way to do it, but not all ways are worth doing.)
### Archive-Zip (1.16)
I needed to create and extract zip files, and was able to do this relatively easily using this module.
The only downside is that I had to study the manual a bit. Thinking of the contents as "member" objects (rather than files) is a little off-putting but it didn't get in the way. Especially since some accessorts are for "files" rather than "members"--I don't understand the difference.
Note: I am told by the author that the module has been completely rewritten, and many of the problems fixed. However, I am no longer working on a project that involved parsing addresses, so I cannot verify this.
Below are previous comments for for v1.11 (which was released in 2002). I do not know if they still apply.
One major problem is that (for US addresses, anyway) it doesn't work unless addresses are very simply formatted:
123 Maple Street, Anytown, ST 12345
Anything beyond that (apartment numbers, post boxes, squares and cross streets, etc.) and it returns nothing.
Often addresses don't fit a simple pattern. (If they all matched that pattern, I wouldn't care about finding a module...)
Worse: it uses Parse::RecDescent, so it takes a few seconds to parse a simple address.
If it worked for most addresses, I'd say the "interface" and "ease of use" were great. Alas...
One note: parsing addresses is a HARD problem.
### if (0.0401)
This is great for conditional "use" lines. It makes code a whole lot more readable than eval'd requires and import calls.
### Win32::Security::SID / Win32-Security (0.50)
I needed a module to process Windows SID (Security Identifier) tags and found it. This did what I needed, though there were some problems:
It doesn't automatically call the ConvertStringSidToSid function like it claims it does (or the call is broken) when converting Sid to Name.
It also doesn't seem to export functions, so I had to use Win32::Security::SID::ConvertSidToName.
Those complaints aside, I'm happy I was able to do what I needed without resorting to non-CPAN modules like Win32::AdminMisc, Win32::UserAdmin, Win32::LanMan etc.
### Text-Toalpha (0.01)
The documentation does not explain at all what this module is for. It even warns "The permutation of characters to letters is not very well permutated," whatever that means.
The source code makes no sense at all as to what it's doing. It *seems* to be converting arbitrary characters to letter sequences and back, but the code doesn't look right. It uses a list and hash with some ord/chr conversions. (Why not use pack/unpack?)
Does anything use this code format?
### File-Defrag (0.03)
The lack of any documentation for something as low-level and critical makes me not want to use this.
From a quick look at the XS source code it looks like it's Linux-only. If so, Linux::Defrag would be a better name.
All the interesting code is in the bin/defrag script: why aren't they in the module instead? It would be useful to have a module with a single defrag_file() function for instance.
The defrag_files() function to defrag all files uses a homegrown directory traversing scheme instead of File::Find.
I would expect a good defragmentation scheme would do a bit of analysis to see which files needed defragmenting (based on how fragmented files were, how often they are accessed or how critical they are, etc.). This version doesn't seem to do any of that.
### Pod::PlainText / Pod-Parser (1.30)
It was incredibly easy to subclass this to create a custom PlainText parser with special commands/behaviors that I wanted, though I did need to deviate from recommended methods to subclass in order to get it to do what I needed. (I'm not sure if it's simply due to an omission in the documentation or not, though.)
### Sub-Usage (0.03)
Providing usage error messages for subroutine calls (in much the same way a command-line program will when it gets back options) is a really neat idea, though the usefulness of this module is probably mooted by something like Params::Validate.
### Test-Prereq (1.027)
This could be a great quality-control tool for module authors, although it is a bit slow in running its tests.
One complaint I have is that I'm not able to get the Build.PL checking tool to work properly, based on the examples. But that's a minor issue since I have the Build generate the Makefile.PL anyway.
Another is (on Windows anyway) is that it chokes on some modules and blocks on input from STDIN. This is a serious-enough bug that I've stopped using it.
### Perl-MinimumVersion (0.01)
I've not tried this yet, so can't vouch for how well it works. But I really really really like the idea behind it!
### Log-Log4perl (0.51)
This is an excellent package, BUT... it's a lot of work to set up the configuration for it. There's a fair bit of documentation to read to figure it out.
For a system of applications which use shared configuration information, this is worth using because a sysadmin can update logging information without touching source code--one can control what subsystems at a set level of granularity are logged (and to where).
But for most cases, I think using a simpler package such as Log::Dispatch will suffice. (It's the basis for Log::Log4perl anyway.) One can easily upgrade from Log::Dispatch to Log4perl if requirements become more complicated.
### Log-Dispatch (2.10)
This is a great system. It's incredibly easy to use and even expand on.
### File-DirWalk (0.1)
How is this better than File::Find (which is a core module)? Maybe in that it gives various callbacks for entering/leaving a directory, but otherwise it has less features. There's no way to control whether to process files or subdirectories first, nor does it provide for filtering etc.
It uses global symbols in opendir(DIR, ...) instead of scoped variables, and does not use File::Spec for portable filename handling, so I'd be leary about using this in production code.
### Test-Portability-Files (0.05)
I haven't compared what this does with the actual Perl portability recommendations, but this seems to be a worthwhile addition to an author's quality (or kwalitee?) assurance toolkit. It's very simple to use.
UPDATE: it's occurred to me that there are some (minor) issues that it doesn't test for. Suppose::You::Have::A::Long::Module::Name, well, each subdirectory is under 32-characters so it passes tests, maybe t/Suppose-You-Have-A-Long-Module-Name.t fails the test but it's easy to rename that to a short name, you you still have it all in a folder called Suppose-You-Have-A-Long-Module-Name-0.123 or whatever that the current version of Test::Portability::Files doesn't test for.
However, I'm not sure it really matters since the limit pertains to "MacOS Classic and old AmigaOS", which should be an option like MSDOS and removed from default tests.
I'm also not sure if it tests for the maximum pathname lengths of Windows 9x or maximum directory depth and length of ISO CD-ROM directories.
But these are easily fixable issues, so shouldn't detract using it.
This is great, but it does not give any warnings when one tries to create junctions to files rather than directories. It also does not document that this should not be done. But it lets you do this...
(I'm not familiar with the API to know if there's hooks to make symlinks to files for use in the future, though.)
### TimeConvert (TimeConvert0.5)
The functionality for converting between "unix seconds to years, days, hours and minutes" can be done with the gmtime function.
Worse, it returns a string "$years years,$days days, $hrs hours,$min minutes and $sec seconds." (from the source code, it's not documente how the result is formatted). So this is not much use. ### Pod-Coverage (0.17) It's great, but it's easy to misunderstand the interface and use it incorrectly so that it looks like a module passes Pod::Coverage tests when it doesn't. Also, there are no hooks to handle inheritence. If a Foo isa('Bar'), then when Foo has methods which override those of Bar, Pod::Coverage doesn't recognize this. Sometimes that's expected behavior: maybe you should odcument exactly what's changed. But sometimes you document it differently, and do not want to list every updated method. It would be nice if there was an option to recognize when this occurs and ignore them. ### pod-mode (0.3) This works well in XEmacs. I'm quite happy to have something like this for editing POD. ### Test-Expect (0.29) I whipped up some tests of a Term::* module quickly with this. It's great! If you've got any module which requires testing by verifying terminal input, use this. It's more foolproof than having a user type things in and is friendlier for cpan smoketesters. My only nitpick is the "Expect" name (it should be called "Test::Term" instead), but understandably the name comes from the use of Expect and Expect::Simple. ### Hoof (0.01) There's absolutely no documentation. Not even an abstract. I have no idea what it does. Why bother uploading it to CPAN if it doesn't even have stub documentation that says what it's for, who the author is (it's the only module under the author's id) and what the license is?!?! ### SQL-Statement (1.10) I've had to use SQL::Parser for some projects that involved analyzing select statements (from various database dialects) to determine the structure of database tables. It was relatively easy to use for my purposes (though it required a patch to handle aliases, which has since been incorporated into 1.10). Most of the work involved analyzing the data structure returned by the structure() method, which required a little bit of experimentation to figure out what I needed (and was the only downside). The documentation is a lot of wade through. A hash structure doesn't seem to be the most elegant way to access this information, but what is? It was enough for me to get what I needed done (and certainly saved me the work of writing a parser). ### Math-XOR (0.02) This is just wrong. From the docs: "This is the only method of encryption that (assuming the randomness of the pattern used as an encryption key) truly cannot be broken." Well, if you had a "truly" random key the size of your file, then theoretically probably. (See the Snake Oil FAQ at <www.interhack.net/people/cmcurtin/sna... All it does is xor two buffers together, and doesn't even check if they are different sizes (which will cause some nasty problems). The namespace is inappropriate, but I wouldn't want to see the Crypt::* namespace polluted with this. ### Time-Traveler (0.01) I'm having a lot of trouble seeing what the use of this module is. Better examples would help explain that. The synopsis is a bad explanation of what it does. If it's an implementation of lazy evaluation, then it seems to have more natural interface than Data::Lazy though with no ability to control whether evaluation is for reads versus writes. If it's for a history, how does one rollback a value? (Note that there's Tie::History for this.) ### Data-Search (0.03) This is an interesting idea, but the implementation leaves a lot to be desired. There are no tests aside from compilation. So how does anyone know it even works? The searching algorithm does not appear to be very efficient: when searching arrays it uses a foreach statement instead of grep or an efficient search algorithm! It doesn't make use of other CPAN modules which might aid in walking data structures or efficient searching. I'm concerned about the use of recursion in walking data structures: for really big data structures this is a memory hog that can bring down a machine. It doesn't handle coderefs! It only allows one to search using Regexps. There's no option to use special code appropriate to objects inside the data structure or anything else that is not stringified. The documentation isn't as clear: can it return the accessor keys, so that if I pass it some mess of hashes and arrays in$data that it will return something likie $data->{key1}->[5]->{key2}->{key3}? What sort of applications is it used for? Perhaps the need to search is due to building an inefficient data structure to begin with? Or maybe one needs to do the searching as one is building the data structure? ### Archive-TarGzip (0.03) I fail to see what improvements this module provides over Archive::Tar. ### Data_Translate (0.2) Is this module really necessary? It's a wrapper for unpack() calls. Worse, it has an object-oriented interface when function calls will do, so there's extra overhead that is not needed. Every conversion function is loaded into memory even if it's not used. (Though the functions seem too simple to justify the AutoLoader.) Also: the translation to/from binary do not take endianness issues into account (sometimes one needs to explicitly use little-endian). I would defend the idea of provided simple and commonly-used functions in a module just to save one from having to re-write the same few lines of code each time, but there should be _some_ extra functionality to justify this. ### Test-Plan (0.02) Everything about this that I've tried is great, except (a big except): it doesn't add any new functionality beyond what's available already. It just adds a better syntax. Problem then is that one needs to require Test::Plan to build the module. Is it worthwhile for module users? I'm not sure. ### Text-Greeking (0.11) This module appears to do the same thing as Text::Lorem, with a very similar interface. ### Weather-Com (0.4.1) I'm neutral as to the quality of this. It seems to be quite an elaborate package for interacting with the Weather Channel's web services. As for the namespace, it's awful. "Weather::Com" is just way too wrong. ### Regexp-Assemble (0.09) Rather that loop through an array of Regexps looking for a match, this module allows for one to combine them all into one Regexp. This makes code much cleaner and easier to maintain. It is an excellent module. Note that I'm not sure how well optimized the combined Regexp is compared to iterating through a loop, but for my purposes this hasn't been a concern. ### CPAN-Mini (0.36) This is a great module for maintaining a "mini" CPAN mirror locally. It's also very easy to subclass so that you can customize its behavior to suit your needs. The only noticeable downside is that it doesn't rebuilt the package-details file based on how you've filtered your copy, but this is minor and will probably be fixed in a later version. ### CPANPLUS::Backend / CPANPLUS (0.051) CPANPLUS::Backend does not make it easy to automate CPAN-related tasks (such as running smoke tests on new CPAN modules). It's not well documented, and the interface is too limited. To get a minimum script running requires quite a bit of hacking and using undocumented or private (names beginning with underscores, "_") methods. For instance, it's hard to dig into a distributions prerequisites in order to determine if there's something that you know doesn't work and have it bail out. Or maybe have it fall back onto a previous version if the latest version fails a test. (It shouldn't be so hard to delve into the inner-workings of the module with some well-placed callbacks. But maybe this is possible, but just not documented?) In certain cases it cannot properly parse the path to the module, requests the wrong URL and just locks up unsure of what to do. (Possibly a Windows-issue with time outs?). The tracking of sent test reports seems to have been eliminated, which improves usage from the CPAN Shell but puts the onus on smoke testers to track results. My frustration has tempted me to just roll my own fetch/extract/run Makefile.PL/make test and send reports code myself, but I do realize what a complicated mess it really is to handle the disgusting underbelly of module installation (especially in a platform-independent manner). So in a perverse way I am grateful for all the work on it. This is an enormous effort so I have high hopes that some day it will be improved. ### Cache-Simple-TimedExpiry (0.22) The module has a simple interface and is easy to use. It seems to work quite well. Alas, the documentation is sloppily formatted with an uncommented minimal example (that's missing an important use statement). It also has no tied interface (which would make it really easy to plug into some existing applications that I have), and for that matter has a poor OO interface: store, fetch and exists with no delete, clear, first_key or next_key methods. (There is a method to return all the keys, but it's not documented.) It also prototypes the subroutines, which means that you have to use parenthesis in method calls. Yuck. If it weren't for the interface, I'd give it 4 stars. ### Comma (0.02) I'm all for coming up with new programming idioms, but I fail to see the use of this module. A tied hash is being used instead of a simple function, so there is a lot of object-oriented overhead behind the scenes that doesn't need to be there, especially when there is only one global instance of the comma object. Looking at the source, locale-specific formatting is automatic. There's no option to customize it, so if you're in one locale but want to produce formats in another locale, then you're out of luck. However, the name 'Comma' is inappropriate for locales that don't group digits with commas. ### Time-Out (0.03) This is a great idea: the module has an intuitive interface for implementing time-outs. And (unlike many other time-out/alarm modules on CPAN) it has tests! The only downside is that it does not work for blocking I/O (at least not on Windows). Note: this is a review of v0.01 ### Win32-Die (0.03) This is a great idea: automatically detect when a module is launched via clicking on an icon in Explorer rather than from the command line, and halting to prevent the window closing when an error occurs. Alas, it's not perfect. It cannot detect when a separate window is launched from within the command line. It also does not trap Ctrl-Breaks. Nor is there a way to customize the error message. Even then, this is a must-have for Win32 Perl developers. ### Regexp-Parser (0.10) This appears to work very well, and has some handy interfaces for iterating over nodes. However, documentation of the specific node-types could use some improvement. ### Win32-Process-Info (1.004) This works really well. My only complaint is that it seems to be a little slow in querying the process list. ### Win32-Console-ANSI (0.07) All one needs to do is add a 'use Win32::Console::ANSI' to the program and it works like a charm. It's great! ### Regexp-Constant (1.22) How is this an improvement over Regexp::Common? ### Test-TempDatabase (0.02) This module doesn't provide options to specify what database one wants: only Postgres is used, so if one doesn't have DBD::Pg, one cannot use it. What does creating a temporary database have to do with Testing? It should be called something like DB::Temp. The abstract/author sections of the Makefile.PL are not updated, and the requirement for DBD::Pg is not specified in the Makefile.PL. Nor has Changes been updated. ### Digest-Crc32 (0.01) What is the point of this module? There is already a Digest::CRC module (which it refers to in the SEE ALSO section) but it says nothing about how or why this module is more appropriate than that or the several other CRC modules. It has a negligable test (only tests the string "foo") and doesn't attempt to account for portential endianess or sign issues. ### File-Info (1.02) This is a rather inappropriately named module, as it deals with caching file information rather than retrieving it. It would be better named something like File::Info::Cache It also supports a uselessly limited number of file types (Unknown, JPEG, or PAR). It stores a line count but not other 'wc' details like word count, longest line, etc. It seems to have the ability to add these features, but examples are not provided. Some sections of the documentation are blank. The Makefile.PL uses a non-standard home made scheme that is not usable by CPANPLUS (or presumably CPAN). ### File-Munger (0.02) I'm having a hard time seeing much use for this module, except as an object-oriented (and possibly platform-independent?) means of getting file information. In which case, the name is completely deceiving: it does no munging (manipulation) whatsoever of the file or attributes. (Admittedly File::Info etc. is already taken, but "Munger" is the wrong name.) The current version (0.02) does not provide any features not already available in the Perl core. Useful things like file type, information relevant to the file type (e.g. image properties or character sets for text files or version information) etc. is not available, nor is platform-independent file information (such as pathnames). The documentation does say more features would be added. It would be nice to know what the "master plan" of the module is. ### SOAP-Lite-0.60a (SOAP-Lite-0.60a) The documentation is ok... there's a lot to wade through, but there's enough to figure out what you need to do. There are examples buried in a lot of documentation. You may need to experiment a bit, but it's easy to get the hang of. It's pretty easy to use, and the interface is good (not excellent, just good). (I'm told it doesn't support all of SOAP's features, but it's handled what I've needed.) The main limitations are in the SOAP protocol itself. There's so much overhead in bandwidth and processing (most of the data is just XML markup that isn't needed) that you're better off using something else. (Not a slight on the module, but on the protocol.) ### Business-ISBN (1.80) I used an older version. For my purposes (validating ISBN numbers before submitting them to a lookup service), it worked. ### Scalar-List-Utils (1.14) This module has a lot of handy functions that give one access to low-level information without resorting to XS. ### Clone::Any / Clone-Any (1.01) It's easy to use, flexible, bundle of joy, etc. etc. and I would give it five stars, but.... If I just used Clone, it would work on most platforms (seems to have passed 26+ tests with no failures) and has no pre-reqs. But if I use Clone::Any, it failed tests on at least one platform (this may be the specific machine it was tested on and not the module's fault, though) and it requires Devel::UseAnyFunc and a separate module capable of cloning. So my choice is to specify using Clone which requires just installing Clone, or I could use Clone::Any, which requires installing Devel::UseAnyFunc and another module for cloning (such as Clone, though Storable is now a core module). It seems like a great idea to just have the module look for whatever cloning routine is available on the system and use it transparently, but it is more work than just installing Clone. (If it were part of the core, that would be something else, but then again, one could just as well speculate if Clone were part of the core...) One other potential problem: if I use Clone::Any instead of Clone, Storable, etc., then I risk that code doesn't work consistently across systems because of bugs in one cloning module on some platforms that is not in the other cloning module. If I at least use a specific cloning module, then I've eliminated some potential problems. ### Class-Meta (0.44) I really like this module. It took be less than 15 minutes to convert a module from a different automation scheme to this one. The interface is very simple to use, and in my opinion, self-documenting. I can look at the code that creates the class and know what kind of data each accessor is, whether it is required, etc. Other class automation modules were too simple. I needed some minimal data validation in the constructors and didn't want to go through making a dummy class with inheritence. There are some minor features that it doesn't have, which I suspect some of the more sophisticated class automation modules do have. But again, this suited my needs. (And portability on Windoze, OS/X, Linux, BSD, etc. is one of them, which the more complex tools don't necessarily have.) ### Class::Accessor::Fast / Class-Accessor (0.19) It does the trick and saves a lot of repetative typing to implement no-frills classes. One downside: there is very little error checking, so if you mistype the name of an accessor when you are constructing it using the new( { accessor => value } ) style, then it will miss it and cause some unexpected problems in your code. If you need more robust features, this might not be for you. ### URI (1.31) This is very good for basic URL manipulation, especially to resolve weirdness between relative and absolute URLs. ### HTML::LinkExtor / HTML-Parser (3.36) I needed to download images from a web page, and used HTML::LinkExtor (part of HTML-Parser) to extract the image src links (based on an example on the module POD!). It took me more time to download the images (lots of them on the page) then to write the code! (A couple of things aren't clear in the documentation, such as whether the attribute hash for the callback is case-sensitive, or if only link attributes are extracted; fortunately for my immediate needs this was not an issue, but it should be explicitly documented.) ### Module::Load / Module-Load (0.10) I was unable to dynamically load modules for test scripts, so I tried this module and it fixed the problem. It's incredibly easy to use. ### TkCarp (1.2) One would expect by default that error messages instantly show up as message boxes, but they don't. One has to specify this. One also has to specify that they show up when they happen, instead of when the program ends. Options are configured by specifying keywords in the use line rather than a hash with attributes, and manually asking for carp and croak since the default behavior isn't what one would expect. croak does not seem to end the program, but causes it to partially lock up (though some events work and one can manually close it). The options are nice, but the default behavior is not what the average developer would expect without reading the documentation. ### Return-Value (1.1) This is a really good module (4.5 stars) for adding diagnostic information to subroutine return values while still returning true/false booleans (using overloading). It's easy to take existing code and add the use of this module to it. The documentation is a little lacking in terms of functional calling style, so one needs to look at the synopsis and extrapolate. The name Return::Value doesn't seem appropriate though. ### RTF-Writer (1.11) I like this module. I like it even better than the RTF::Generator module which I wrote (which *cough* doesn't work well in current versions of Perl and is an incomplete implementation anyway). The interface is clean and simple to work with. I was able to produce an RTF very quickly. The only downside is that you need to know the RTF and work with the (sometimes nasty) RTF innards rather than an abstract document in general. ### Text-Balanced (1.95) This works great for extracting balanced strings, BUT.... Read the documentation closely, since it does some unexpected (not functional-programming-friendly) modification of arguments in scalar context. Once I read the documentation and realized what was going on, I got it working as I needed it. It can be a very good alternative to Parse::RecDescent when you're concerned about balanced parenthesis, quotes, brackets, etc. but otherwise simple grammars. ### Class-DBI (0.96) It took me a while before getting around to trying Class::DBI. I really like it a lot more now, but it's not the easiest thing to use for a pre-existing database that may not have the best schema design in the world. Sometimes simple database queries can be awkward, and it may take a while to debug the class design for joined tables. It takes getting used to the iterator "pattern' of retriving database records. (I'm rather ambivalent about that style of programming.) It's also awkward to specify dynamic connection parameters, but it can be done with some expiermentation. It's just not well documented. Note: my review is for 0.95, because i cannot get 0.96 working on my platform. and the rating system will not let me specify an earlier version. ### Params-Validate (0.74) This is a great module for validating named or unamed subroutine and method parameters. It's easy to use, and seems to work without any problems. My only "complaint" (read: wishlist item) is that there's no way to have both unnamed and named calling styles. ### Test-Warn (0.08) The interface is a little awkward, but it works well and allows you to test warnings. ### Parse-CPAN-Packages (2.21) This module allows one to easily parse the 02packages.details.txt.gz file for CPAN archives. The major downside is that it has to initialize itself completely, which can take a while even on a fast machine (and will probably take longer as CPAN grows). A couple of features such as determining what distribution a module is in required reading the source code since the documentation consists only of a synopsis, which leaves out a few things. ### File-Temp (0.14) This module seems to do what it claims: create temporary directories and files and clean them up when the program is done, without having to do any book-keeping. It's very easy to use. ### Win32-TieRegistry (0.24) This allows for very easy access to the Windows registry through hash keys. It's incredibly easy to use, although I've not been able to set defaults in the 'use' line as the documentation describes. ### XML-Parser-EasyTree (0.01) This was really easy to use and allowed me to quickly parse a simple XML document. ### Devel-Cover (0.45) This is an excellent module! I've not only improved the test suite but used it to optimize software by identifying conditions that do not occur, or options that are not needed. The documentation leaves a bit to be desired, though. It takes a bit of time and experimentation to figure out. (There are still a few things that I'll need to figure out...) ### SVG-Graph (0.01) This looks like it has the potential to become an amazing distribution for generating SVG diagrams. But it's barely documented (as if a utility was used to create POD by looking at the methods): there's a lot of empty templates listing methods, and that's it for most of the modules. It's difficult to figure out, and I decided it would be easier to just find another module to do what I needed (which was to create a node diagram.... it appears that it at least has hooks to do this, if not the actual ability). I have not tried it for plotting data. That said, the documentation refers to it as pre-alpha. But it came out in November 2003. ### UML-State (0.02) This program is excellent for creating state diagrams, either through a text or XML file that describes the states and connections between them. You need to define the state positions in rows, and then define how they are connected. The process is easy to figure out, and it's certainly faster to create an XML file than to twiddle with a drawing program. Alas, this is almost-just-what-I-needed in that you cannot change the shape or size of the nodes (they are just equal-sized rectangles), and I need a general purpose tool for creating node diagrams. ### Statistics-Descriptive (2.6) This is a very easy-to-use module to show some basic statistics on some data. It's worth using rather than "rolling your own", even on a one-off script. ### Attribute-Types (0.10) From some very limited experiments, this is a very simple and effective way to control the types and values of variables in Perl. This is a good way to enforce types or to catch errors in debugging. Though I'm unsure about using it in production code, especially since attributes are (were?) a moving target and subject to change. A *major downside* is that assignment to variables is seriously slowed down, due to the fact that they become tied to a function that restricts their type. So don't use it for any time-sensitive code. And of course it seems to increase a variable's size. ### Text-Replace (0.07) Is it possible the author has something to do with this? samson.akitadiamonds.com/ "On the internet, nobody knows you're a dog." ### Devel-Size (0.58) This is a very useful module for obtaining memory usage information of objects. It's quite surprising to see just how much memory some things really use! An obvious downside is that it doesn't work for every type of object. It would be nice to obtain additional information about memory usage in Perl (such as total used memory of a module, or available memory, etc). ### Tk-Date (0.40) I've been able to get it to do most of what I wanted, without having to write my own date/time input functions. I can live without the features that it doesn't have (AM/PM time input is in the TODO list) or that I've yet to figure out. ### Win32-TaskScheduler2.0.3 (Win32-TaskScheduler2.0.3) My overall rating is 3 out of 5 because of ambivalence. I had trouble compiling it due to some vague function calls, but eventually found a SourceForge page at taskscheduler.sourceforge.net that had a compiled version to download via ActiveState's PPM. The documentation did not mention this (it has a blank SEE ALSO section). The Source Forge site refers to the Windows documentation, but that leaves something to be desired as well. It follows the Windows interface style too closely. You use New() instead of new(), and have to manually call the End() destructor. There's no option to import constants, so you have to use Win32::TaskScheduler::CONSTANT or$obj->CONSTANT. I would rather the interface followed traditional Perl style and calling conventions.
However, I figured out how to get it to do what I needed within a few minutes. And it seems to work relatively well.
### Tk-Wizard-Bases (1.06)
In some ways this is an excellent module. When running, it looks quite professional.
Alas, there are some issues: it is designed as a MainWindow (e.g. as a standalone application) and so is not easy to embed as a Toplevel window within an application.
Stylistically it looks like a Windows 95 or 2000 installation wizard, which is not appropriate for a wizard that occurs within an application and may bother or confuse some non-Windows people.
Tests are not automated, as it runs actual wizards that require human intervention. It also requires manually moving some image files into the perl directory for the tests to work.
The documentation leaves much to be desired. It's sparse and recommends one look at the test case files.
It makes some assumptions about how wizards should work that are restrictive. For instance, there is no way to have both "Finish" and "Next" buttons in cases where the user can end early.
Also: E-mails to the author have bounced back.
Sadly, this is a case where an otherwise excellent module has a lot of issues that make it too restrictive for my needs.
### Data-Page (2.00)
Given a list of items, the number of items per page, and a page number, this module only manages where the starting item number is, and it gives you an array slice for that page.
Understandably, it doesn't manage how to view the pages since they can be implemented via Tk, HTML/CGI, console, etc.
However, more functions to handle paging would be good. Such as a goto function to go to a particular page (page n, previous page, next page, etc.).
Without such functions, you still need to keep track of the page number, and to recreate the object for each page. So it has a limited usefulness.
### enum (1.016)
This is very useful, although I have not tested it beyond simple enumerated lists. It should be a core module.
One thing it can't do, but this is largely a Perl limitation:
use enum qw( FOO BAR );
my %MOO = (
FOO => 'Foo',
BAR => 'Bar',
);
### Pod-POM (0.17)
This was surprisingly easy to use. I needed to do some specialized parsing of POD and convert to HTML, and it worked right out of the box.
It was easier to figure out than Pod::HTML in terms of interface and documentation.
One downside is that it has problems extracting POD from code. One needs to use a separate module to do this.
### XML-Generator (0.98)
This module is very easy to use: it's similar to the kind of interface that I was looking for (and would have written had I not found it), which is basically to use AUTLOAD to use method names as the XML elements (similar to the way CGI does).
Cons: the pretty printing doesn't handle attributes well, and it's difficult to handle the namespace attributes (which to be honest I haven't figured out from the XML specs themselves).
### Win32-Daemon-Simple-0.2.2 (Win32-Daemon-Simple-0.2.2)
Various problems with this module that keep it from working out of the box: It requires various other modules but the Makefile.PL does not specify them. Then it uses a symbol \$HKLM which is not defined, so it basically dies with a compilation error.
### Carp-Assert (0.18)
Having assertions makes development and debugging much easier.
The only down sides are that it's not part of the standard Perl distribution, and (maybe I'm wrong about this) if a module uses it, can the script that uses that module override the use/no Carp::Assert setting.
### Win32-SerialPort (0.19)
This module hasn't been updated since 1999. That's a serious issue.
The interface is messy and one needs to study the examples, but supposedly it's the same as Device::SerialPort.
A problem is that I need to write klugy code in a BEGIN block to test if I'm in Windows and use the Windows::SerialPort module instead of Device::SerialPort. Somebody should look to merging the two modules.
[Ok... I've since realized that Device::SerialPort is a mimic of the Win32 module, but still, there should be ONE module.]
However, it seems to do what I need it to.
### Parse-Binary (0.06)
I needed a simple and dynamic way to create and parse binary data formats to communicate with a GPS device using a serial interface. I was about to roll my own when I stumbled across this module.
I've been using Parse::Binary::FixedFormat. It's simple and does the trick. And it makes my code much easier to maintain.
### HTML-Template (2.6)
Note: this review applies to earlier versions of HTML::Template.
This is an excellent module. This one has made web application development much easier for me.
The only downside is with using simple loops with one value. It seems like a kluge to have to convert an array into a hash. It's also awkward to specify a "default" option for select lists. These are both common issues that I think deserve implementation in the module. | {"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": 0.27826422452926636, "perplexity": 2324.980974563316}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-22/segments/1558232259316.74/warc/CC-MAIN-20190526145334-20190526171334-00133.warc.gz"} |
https://rd.springer.com/chapter/10.1007%2F978-981-13-1316-5_22 | Upgrade of the ATLAS Thin Gap Chamber Electronics for HL-LHC
• Tomomi Kawaguchi
• on behalf of the ATLAS Muon Collaboration
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 213)
Abstract
The High-Luminosity LHC (HL-LHC) is planned to start its operation in 2026 with an instantaneous luminosity of $$7.5\times 10^{34}\,\mathrm{cm}^{-2} \mathrm {s}^{-1}$$. Studies with data taken by ATLAS indicate that the upgraded first level trigger with fast tracking for HL-LHC can reduce the rate of a single muon trigger by 25% for the $$p_{\mathrm {T}}$$ threshold of 20 GeV while maintaining similar efficiency. First prototype of the ATLAS Thin Gap Chamber frontend board has been developed with most of the functions required for HL-LHC implemented. Performance of data transfer has been demonstrated with charged particle beams at the CERN SPS beam facility.
References
1. 1.
Apollinari, G., et al.: High-Luminosity Large Hadron Collider (HL-LHC) Preliminary Design Report. CERN-2015-005. https://cds.cern.ch/record/2116337
2. 2.
ATLAS Collaboration: The ATLAS Experiment at the CERN Large Hadron Collider. JINST 3 S08003 (2008)Google Scholar
3. 3.
ATLAS Collaboration: ATLAS Phase-II Upgrade Scoping Document. CERN-LHCC-2015-020. https://cds.cern.ch/record/2055248
4. 4.
Kawamoto, T., et al.: New Small Wheel Technical Design Report. CERN-LHCC-2013-006, ATLAS-TDR-020. https://cds.cern.ch/record/1552862
5. 5.
ATLAS Muon Collaboration: ATLAS Muon Spectrometer Technical Design Report. CERN/LHCC 97-22. https://cds.cern.ch/record/331068
6. 6. | {"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": 0.8701031804084778, "perplexity": 12112.87358462304}, "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-2018-43/segments/1539583508988.18/warc/CC-MAIN-20181015080248-20181015101748-00079.warc.gz"} |
http://talkstats.com/threads/estimating-mean-of-a-poisson-distribution-based-on-interval-censoring.63967/ | # Estimating Mean of a Poisson Distribution Based on Interval censoring
#### mohsenhs82
##### New Member
Dear all,
I appreciate that if you let me know if there is any package implemented in R for Estimating Mean of a Poisson Distribution Based on Interval censoring? And if yes, could you please provide some information about it
By the way, is there anything for lognormal?I think fitdistcens is not good for this purpose as it gives me different result compared to SAS and only useful for right/left censoring and not interval censoring (or both left and right together).
Kind regards,
Mohsen | {"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": 0.9195657968521118, "perplexity": 787.7716900499396}, "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-2022-33/segments/1659882572089.53/warc/CC-MAIN-20220814234405-20220815024405-00319.warc.gz"} |
https://agenda.infn.it/event/11062/?view=event | 1. General Seminars
# Measurement of hadronic cross-sections with CMD-3 at VEPP-2000
## by Prof. Evgeny Solodov (Budker INP)
Europe/Rome
Aula Seminari (LNF INFN)
### Aula Seminari
#### LNF INFN
Description
The first round of data taking with CMD-3 detector at VEPP-2000 e+e collider (BINP, Novosibirsk, Russia) was performed in 2011-2013. The CMD-3 is the general purpose particle detector, equipped by tracking system, two crystal (CSI and BGO) calorimeters, liquid Xe calorimeter, TOF and muon systems. The main goal of experiments at CMD-3 is the measurement of cross-sections and dynamics of exclusive modes of e+e- —> hadrons. In particular, these results provide important input for calculation of the hadronic contribution to the muons anomalous magnetic moment. Here we present the survey of results of analysis of data taken in 2011-2013, including modes of e+e- —> hadrons with up to 6 pions or 2 kaons in final state. About 60 1/pb were taken in the energy range from 0.32 to 2.0 GeV in c.m. The beam energy was continuously measured concurrently with the data taking using Compton backscattering. In 2016 VEPP-2000 resumed operations after upgrade with project luminosity of 1032cm2s-1 at 2 GeV. | {"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": 0.8974326848983765, "perplexity": 7755.668405733943}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400198942.13/warc/CC-MAIN-20200921050331-20200921080331-00724.warc.gz"} |
http://blog.csdn.net/ghui23/article/details/51537080 | # [python][leetcode]Intersection of Two Arrays II
Given two arrays, write a function to compute their intersection.
Example:
Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2, 2].
Note:
Each element in the result should appear as many times as it shows in both arrays.
The result can be in any order.
Follow up:
What if the given array is already sorted? How would you optimize your algorithm?
What if nums1’s size is small compared to num2’s size? Which algorithm is better?
What if elements of nums2 are stored on disk, and the memory is limited such that you cannot load all elements into the memory at once?
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class Solution(object):
def intersect(self, nums1, nums2):
"""
:type nums1: List[int]
:type nums2: List[int]
:rtype: List[int]
"""
res=[];diction={}
for num1 in nums1:
if not diction.has_key(num1):
diction[num1]=1
else:
diction[num1]+=1
for num2 in nums2:
if diction.has_key(num2) and diction[num2]>=1:
diction[num2]-=1
res.append(num2)
return res
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举报原因： 您举报文章：[python][leetcode]Intersection of Two Arrays II 色情 政治 抄袭 广告 招聘 骂人 其他 (最多只允许输入30个字) | {"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": 0.2607395648956299, "perplexity": 14194.709174275224}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "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-2018-05/segments/1516084887600.12/warc/CC-MAIN-20180118190921-20180118210921-00799.warc.gz"} |
http://science.sciencemag.org/content/234/4778/870 | Reports
# Vertical Nitrate Fluxes in the Oligotrophic Ocean
See allHide authors and affiliations
Science 14 Nov 1986:
Vol. 234, Issue 4778, pp. 870-873
DOI: 10.1126/science.234.4778.870
## Abstract
The vertical flux of nitrate across the thermocline in the upper ocean imposes a rigorous constraint on the rate of export of organic carbon from the surface layer of the sea. This export is the primary means by which the oceans can serve as a sink for atmospheric carbon dioxide. For the oligotrophic open ocean regions, which make up more than 75% of the world's ocean, the rate of export is currently uncertain by an order of magnitude. For most of the year, the vertical flux of nitrate is that due to vertical turbulent transport of deep water rich in nitrate into the relatively impoverished surface layer. Direct measurements of rates of turbulent kinetic energy dissipation, coupled with highly resolved vertical profiles of nitrate and density in the oligotrophic eastern Atlantic showed that the rate of transport, averaged over 2 weeks, was 0.14 (0.002 to 0.89, 95% confidence interval) millimole of nitrate per square meter per day and was statistically no different from the integrated rate of nitrate uptake as measured by incorporation of 15N-labeled nitrate. The stoichiometrically equivalent loss of carbon from the upper ocean, which is the relevant quantity for the carbon dioxide and climate question, is then fixed at 0.90 (0.01 to 5.70) millimole of carbon per square meter per day. These rates are much lower than recent estimates based on in situ changes in oxygen over annual scales; they are consistent with a biologically unproductive oligotrophic ocean. | {"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": 0.8588876724243164, "perplexity": 1978.2468807847881}, "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-2018-09/segments/1518891813803.28/warc/CC-MAIN-20180221202619-20180221222619-00327.warc.gz"} |
https://www.physicsforums.com/threads/quotient-topology.54155/ | # Quotient topology
1. ### shankarvn
13
Can someone explain the concept of Quotient topology. I tried to read it from a book on topology by author "James Munkres" . It was okay but I did not get a feel of what he was trying to do.. He talks about cutting and pasting elements. I kind of got lost in that.. If someone could give me a physical picture, it would be great.. I beleive this is an important concept. Looking forward to your replies.
Shankar
2. ### mathwonk
9,814
I have not used this concept too much, but I recall a little from reading kelley, general topology.
take any topological space X and any surjective map X-->Y to a set Y. then this map will be continuous with certain topologies on Y and not continuous with others.
i.e. the map is continuous iff every open set in Y ahs an open inverse image. so the more open sets Y has, the harder it is for the map to be continuous. E.g. if Y has the smallest possible topology, with only the empty set and Y open, the map is always continuous.
suppose we give Y the largest number of open sets, such that the map is still continuous. this i believe is called the quotient topology on Y.
i.e. given any surjective map X-->Y, we can view Y as made by taking a "quotient" of X by an equivalence relation.
just consider two points of X equivalent if they have the same image under the map.
Then given such a quotient space Y of X, the points of Y are actually subsets of X. Then the quotient topology on Y is expressed as follows: a set in Y is open iff the union in X of the subsets it consists of, is open in X.
This is a basic but simple notion. important, but nothing deep here except the idea of continuity, and the general idea of enhancing the structure of a set of equivalence classes.
the same thing goes on everywhere. given a group and a normal subgroup, one gets an equivalence relation on the elements of the group and makes a group out of these classes.
given a ring and an ideal one makes a ring out of the quotient object.
in general quotient constructions are techniques for constructing "maximal" targets for surjective maps subject to a certain condition.
I'm sorry. you asked for a physical picture. imagine the real line mapping to the circle by the map taking t to (cos(t),sin(t)). the "wrapping map" or polar coordinates map. then try to convince yourself that the quotient topology is exactly the usual topology on the circle.
Last edited: Nov 30, 2004
3. ### shankarvn
13
Thank you sir. That helps. Can you throw some more light on the wrapping example that you gave in the last line. I believe everything in mathamatics tries to capture some physically intuitive idea. So I guess there should be more to this idea. I guess most geometries are obtained by cutting, wrapping and pasting exisitng geometries. Can you tell me more about this.(since it looks important to me)?Just an example will do. Thanks again.
4. ### mathwonk
9,814
have you seen polar coordinates? one measures angles on a circle by radians. i.e. t radians corresponds to a certain point on the circle. so if we have a straight t - axis, then sending 0 to the point (1,0) on the circle, and sending the point on the t axis, at distance t from the origin, to the point on the unit circle whose arclength from (1,0) has length equal to t, is called the polar coordinate map, or wrapping map.
think of wrapping a straight thread around a circular spool.
in coordinates it is given by cosine and sine. i.e. we map the t- line onto the unit circle by sending the point with coordinate t on the t - line, to the point with coordinates (cos(t), sin(t)) on the unit circle.
somehow i feel i am not understanding your question. usually in this situation someone else does, and steps in and helps out. maybe they will.
5. ### shankarvn
13
Thank you sir
Shankar
6. ### mathwonk
9,814
mr shankar you are a gentleman and a scholar.
7. ### talolard
125
Maybe a few years late to the party, but thats an excellent explanation. ThankYou. | {"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": 0.8827628493309021, "perplexity": 472.458909757478}, "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/1438042991019.80/warc/CC-MAIN-20150728002311-00175-ip-10-236-191-2.ec2.internal.warc.gz"} |
http://cameron.pfiffer.org/2018/02/26/tufte-stufte/ | Cameron's Blog - Tufte Stufte
# Tufte Stufte
## Contents
This is not a margin note.This is a margin note. As you can see, it is to the right of the left, and it indeed appears to be smaller. Were it a margin note as one might presuppose, it would be to the right of the left and perhaps a bit smaller.
In the having of a new thought, I find myself overcome with thoughtfulness. You might say, perhaps you would be! You would be overcome with thoughtfulness, as it is a thought.
Thank you for saying so.
Quick, look at some math! $x = 2+2$ Tell me, what is $x$?
Even better, here is a chart with made-up numbers. Look how fancy and interactive it is.
Don’t worry, it’s quite boring – you’re not missing out on anything.But no, in all seriousness, I thought I’d take the chance to explore Bezier curves while I’m mucking about with some fun looking theming. Bezier curves came up at work, the details of which I don’t really know whether or not I can share. So, I won’t.
bezier <- function(t, p) {
# A simple Bezier curve
x = (1 - t) * (1 - t) * p[1, 1] + 2 * (1 - t) * t * p[2,1] + t * t * p[3,1]
y = (1 - t) * (1 - t) * p[1, 2] + 2 * (1 - t) * t * p[2,2] + t * t * p[3,2]
return(c(x,y))
}
points <- matrix(c(0, 5, 1, 0, 2, 3), ncol = 2)
line <- matrix(bezier(0:100/100, points), ncol=2)
head(line)
## [,1] [,2]
## [1,] 0.0000 0.0000
## [2,] 0.0991 0.0399
## [3,] 0.1964 0.0796
## [4,] 0.2919 0.1191
## [5,] 0.3856 0.1584
## [6,] 0.4775 0.1975
Basically, we just plot a bunch of smaller points on a new, continuously defined function that has a nifty little bend in it.
Neato. What a great Bezier curve. Thanks to xan on StackOverflow for providing the pseudocode for that Bezier curve.
Now, I’d like to ask you to hang out with that curve for a little while and consider it’s elegance, if you would be so kind. | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 2, "mathjax_display_tex": 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": 0.6372653841972351, "perplexity": 1193.018222580698}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-35/segments/1566027318952.90/warc/CC-MAIN-20190823172507-20190823194507-00506.warc.gz"} |
https://worldwidescience.org/topicpages/h/h2+discharges+spatial.html | #### Sample records for h2 discharges spatial
1. Production mechanism of negative pionlike particles in H2 gas discharge plasma
International Nuclear Information System (INIS)
Uramoto, Joshin.
1996-04-01
Negative pionlike and muonlike particles are produced by an electron bunch and a positive ion bunch which are generated controllably from an electron beam and a gas. Physical characteristics of the negative pionlike particles are the same with those of negative pionlike particles extracted from the H 2 gas discharge. Thus, the production mechanism in the H 2 gas discharge is deduced. (author)
2. Nanosecond pulsed discharges in N2 and N2/H2O mixtures
NARCIS (Netherlands)
Joosten, R.M.; Verreycken, T.; Veldhuizen, van E.M.; Bruggeman, P.J.
2011-01-01
Nanosecond pulsed discharges in N2 and N2/H2O at atmospheric pressure between two pin-shaped electrodes are studied. The evolution of the discharge is investigated with time-resolved imaging and optical emission spectroscopy. The discharge consists of three phases, the ignition (mainly molecular
3. Gas phase hydrogen peroxide production in atmospheric pressure glow discharges operating in He - H2O
NARCIS (Netherlands)
Vasko, C.A.; Veldhuizen, van E.M.; Bruggeman, P.J.
2013-01-01
The gas phase production of hydrogen peroxide (H2O2) in a RF atmospheric pressure glow discharge with helium and water vapour has been investigated as a function of the gas flow. It is shown that the production of H2O2 is through the recombination of two OH radicals in a three body collision and the
4. Investigation on the mode of AC discharge in H2O affected by temperature
Science.gov (United States)
Siyuan, DONG; Shaomeng, GUO; Dan, WEN; Xiaoliang, TANG; Gao, QIU
2018-04-01
In this paper, some experimental equipment has been set up for kHz frequency AC liquid phase discharge, and the temperature of the deionized water was regulated during discharge. The electrical characteristics and spectra of liquid phase H2O discharge have been investigated. Two discharge modes, high temperature and low temperature, were both found. The results show that there are two mechanisms in liquid phase discharge: the field ionization mechanism and the breakdown mechanism of bubbles, and these two mechanisms are always developed simultaneously; the temperature is the key factor determining the discharge type. At high temperature, the breakdown of bubbles is the main discharge mechanism, and the field ionization mechanism occurs mainly at low temperature.
5. Nanoparticle formation in H2O/N-2 and H2O/Ar mixtures under irradiation by 20 MeV protons and positive corona discharge
DEFF Research Database (Denmark)
Imanaka, M.; Tomita, S.; Kanda, S.
2010-01-01
To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using...
6. Photolysis of low concentration H2S under UV/VUV irradiation emitted from high frequency discharge electrodeless lamps.
Science.gov (United States)
Xu, Jianhui; Li, Chaolin; Liu, Peng; He, Di; Wang, Jianfeng; Zhang, Qian
2014-08-01
The photolysis of low concentration of H2S malodorous gas was studied under UV irradiation emitted by self-made high frequency discharge electrodeless lamp with atomic mercury lines at 185/253.7nm. Experiments results showed that the removal efficiency (ηH2S) of H2S was decreased with increasing initial H2S concentration and increased slightly with gas residence time. ηH2S was increased dramatically with relative humidity from<5% to 43% while the concentration of oxygen in gas environments affected the removal of H2S. The mechanisms for direct and indirect photolysis (generation of ozone) were illustrated by the experimental results on photolysis of H2S under argon environments and ozonation of H2S under air environments, respectively. The overall ηH2S by photolysis is higher than the combination of ηH2S by direct photolysis and ozonation, suggesting that hydroxyl radical-mediated indirect photolysis played an important role during photolysis processes. The main photolysis product was confirmed to be SO4(2-) with ion chromatograph. Copyright © 2014 Elsevier Ltd. All rights reserved.
7. Primordial Synthesis of Amines and Amino Acids in a 1958 Miller H2S-Rich Spark Discharge Experiment
Science.gov (United States)
Parker, Eric T.; Cleaves, Henderson J.; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael; Aubrey, Andrew; Lazcano, Antonio; Bada, Jeffrey L.
2011-01-01
Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordia! environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.
8. Time and spatially resolved LIF of OH in a plasma filament in atmospheric pressure He-H2O
International Nuclear Information System (INIS)
Verreycken, T; Van der Horst, R M; Baede, A H F M; Van Veldhuizen, E M; Bruggeman, P J
2012-01-01
The production of OH in a nanosecond pulsed filamentary discharge generated in pin-pin geometry in a He-H 2 O mixture is studied by time and spatially resolved laser-induced fluorescence. Apart from the OH density the gas temperature and the electron density are also measured. Depending on the applied voltage the discharge is in a different mode. The maximum electron densities in the low- (1.3 kV) and high-density (5 kV) modes are 2 × 10 21 m -3 and 7 × 10 22 m -3 , respectively. The gas temperature in both modes does not exceed 600 K. In the low-density mode the maximum OH density is at the centre of the discharge filament, while in the high-density mode the largest OH density is observed on the edge of the discharge. A chemical model is used to obtain an estimate of the absolute OH density. The chemical model also shows that charge exchange and dissociative recombination can explain the production of OH in the case of the high-density mode. (paper)
9. Gas-phase evolution of Ar/H2O and Ar/CH4 dielectric barrier discharge plasmas
Science.gov (United States)
Barni, Ruggero; Riccardi, Claudia
2018-04-01
We present some experimental results of an investigation aimed to hydrogen production with atmospheric pressure plasmas, based on the use of dielectric barrier discharges, fed with a high-voltage alternating signal at frequency 30-50 kHz, in mixtures of methane or water vapor diluted in argon. The plasma gas-phase of the discharge was investigated by means of optical and electrical diagnostics. The emission spectra of the discharges was measured with a wide band spectrometer and a photosensor module, based on a photomultiplier tube. A Rogowski coil allowed to measure the electric current flowing into the circuit and a high voltage probe was employed for evaluating the voltage at the electrodes. The analysis of the signals of voltage and current shows the presence of microdischarges between the electrodes in two alternating phases during the period of oscillation of the applied voltage. The hydrogen concentration in the gaseous mixture was measured too. Besides this experimental campaign, we present also results from a numerical modeling of chemical kinetics in the gas-phase of Ar/H2O and Ar/CH4 plasmas. The simulations were conducted under conditions of single discharge to study the evolution of the system and of fixed frequency repeated discharging. In particular in Ar/H2O mixtures we could study the evolution from early atomic dissociation in the discharge, to longer time scales, when chemical reactions take place producing an increase of the density of species such as OH, H2O2 and subsequently of H and H2. The results of numerical simulations provide some insights into the evolution happening in the plasma gas-phase during the hydrogen reforming process.
10. Kinetic model of a Ne-H2 Penning Recombination Laser operating in the hollow cathode discharge
International Nuclear Information System (INIS)
Pramatarov, P.M.; Stefanova, M.S.; Petrov, G.M.
1995-01-01
The Penning Recombination Laser (PRL) requires the presence of both a recombination plasma populating the upper laser level (ULL) and a gas component efficiently depopulating the lower laser level (LLL) by Penning reactions. Such requirements are met in the negative glow plasma of a pulsed high voltage Ne-H 2 discharge with a helical hollow cathode. High rates of ionizations followed by recombinations are reached due to the beam component of non-Maxwellian electrons of 1-2 keV energy present in the tail of the electron energy distribution function. The H 2 , on the one hand plays the role of Penning component and on the other hand effectively cools the electrons by rotational and vibrational levels excitation. The latter contributes to the effectiveness of the recombination processes. A kinetic model of the physical processes determining the inversion population on the NeI(2p 1 -1s 2 ) transition (the 585.3 nm line) in a Ne-H 2 PRL operating in a high voltage hollow cathode discharge at intermediate pressures is proposed. About 60 plasma-chemical reactions are considered in the model. These include: two-electron recombination of Ne + ; dissociative recombination of Ne 2 + , NeH + and H 2 + ; ion-ion recombination of Ne + and H - ; Ne and H 2 direct ionization by fast electrons; Ne stepwise ionization; Penning ionization; Ne excitation by fast electrons; Ne stepwise excitation and de-excitation; radiative transitions; electron mixing between Ne excited states; H 2 rotational and vibrational levels excitation; H 2 dissociative attachment; elastic electron collisions with H 2 and Ne. The rate constants for the reactions are either taken from the literature or calculated in this work
11. Photolysis of low concentration H2S under UV/VUV irradiation emitted from microwave discharge electrodeless lamps.
Science.gov (United States)
Xia, Lan-Yan; Gu, Ding-Hong; Tan, Jing; Dong, Wen-Bo; Hou, Hui-Qi
2008-04-01
The photolysis of simulating low concentration of hydrogen sulfide malodorous gas was studied under UV irradiation emitted by self-made microwave discharge electrodeless lamps (i.e. microwave UV electrodeless mercury lamp (185/253.7 nm) and iodine lamp (178.3/180.1/183/184.4/187.6/206.2 nm)). Experiments results showed that the removal efficiency (eta H2S) of hydrogen sulfide was decreased with increasing initial H2S concentration and increased slightly with gas residence time; H2S removal efficiency was decreased dramatically with enlarged pipe diameter. Under the experimental conditions with pipe diameter of 36 mm, gas flow rate of 0.42 standard l s(-1), eta H2S was 52% with initial H2S concentration of 19.5 mg m(-3) by microwave mercury lamp, the absolute removal amount (ARA) was 4.30 microg s(-1), and energy yield (EY) was 77.3 mg kW h(-1); eta H2S was 56% with initial H2S concentration of 18.9 mg m(-3) by microwave iodine lamp, the ARA was 4.48 microg s(-1), and the EY was 80.5mg kW h(-1). The main photolysis product was confirmed to be SO4(2-) with IC.
12. LIF diagnostics of hydroxyl radical in atmospheric pressure He-H2O dielectric barrier discharges
Czech Academy of Sciences Publication Activity Database
Dilecce, G.; Ambrico, P. F.; Šimek, Milan; De Benedictis, S.
2012-01-01
Roč. 398, č. 4 (2012), s. 142-147 ISSN 0301-0104 Institutional research plan: CEZ:AV0Z20430508 Keywords : Spectroscopic Techniques * Plasma Diagnostics * LIF * OH * Dielectric Barrier Discharge Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.957, year: 2012
13. Spectroscopic diagnostics and modeling of Ar/H2/CH4 microwave discharges used for nanocrystalline diamond deposition
International Nuclear Information System (INIS)
Lombardi, G.; Hassouni, K.; Benedic, F.; Mohasseb, F.; Roepcke, J.; Gicquel, A.
2004-01-01
In this paper Ar/H 2 /CH 4 microwave discharges used for nanocrystalline diamond chemical vapor deposition in a bell-jar cavity reactor were characterized by both experimental and modeling investigations. Discharges containing 1% CH 4 and H 2 percentages ranging between 2% and 7% were analyzed as a function of the input microwave power under a pressure of 200 mbar. Emission spectroscopy and broadband absorption spectroscopy were carried out in the UV-visible spectral range in order to estimate the gas temperature and the C 2 density within the plasma. Infrared tunable diode laser absorption spectroscopy was achieved in order to measure the mole fractions of carbon-containing species such as CH 4 , C 2 H 2 , and C 2 H 6 . A thermochemical model was developed and used in order to estimate the discharge composition, the gas temperature, and the average electron energy in the frame of a quasihomogeneous plasma assumption. Experiments and calculations yielded consistent results with respect to plasma temperature and composition. A relatively high gas temperature ranging between 3000 and 4000 K is found for the investigated discharge conditions. The C 2 density estimated from both experiments and modeling are quite high compared with what is generally reported in the literature for the same kind of plasma system. It ranges between 10 13 and 10 14 cm -3 in the investigated power range. Infrared absorption measurements and model predictions indicate quite low densities of methane and acetylene, while the atomic carbon density calculated by the model ranges between 10 13 and 10 15 cm -3 . The methane and hydrogen introduced in the feed gas are subject to a strong dissociation, which results in a surprisingly high H-atom population with mole fraction ranging between 0.04 and 0.16. Result analysis shows that the power coupling efficiency would range between 70% and 90%, which may at least explain the relatively high values obtained, as compared with those reported in the
14. Study of nanosecond discharges in H2-air mixtures at atmospheric pressure for plasma assisted combustion applications
Science.gov (United States)
Kobayashi, Sumire; Bonaventura, Zdeněk; Tholin, Fabien; Popov, Nikolay A.; Bourdon, Anne
2017-07-01
This paper presents 2D simulations of nanosecond discharges between two point electrodes for four different H2-air mixtures defined by their equivalence ratios ϕ (i.e. φ =0, air, φ =0.3, lean mixture, φ =1, stoichiometric mixture and φ =1.5, rich mixture) at atmospheric pressure and at an initial temperature of 1000 K. In a first step, we have shown that the mixture composition has only a very small influence on the discharge dynamics and structure during the streamer phase and up to the formation of the plasma channel between the two point electrodes in H2-air mixtures with φ \\in [0,1.5]. However, as the plasma channel is formed slightly earlier as the equivalence ratio increases, for a given voltage pulse, the duration of the nanosecond spark phase increases as the equivalence ratio increases. As expected, we have shown that excited states of N2 (and in particular N2(A)) and radicals (and in particular O(D), O(P), H and OH) are very efficiently produced during the voltage pulse after the start of the spark phase. After the voltage pulse, and up to 100 ns, the densities of excited states of N2 and of O(D) decrease. Conversely, most of the O(P), H and OH radicals are produced after the voltage pulse due to the dissociative quenching of electronically excited N2. As for radicals, the gas temperature starts increasing after the start of the spark phase. For all studied mixtures, the density of O(P) atoms and the gas temperature reach their maxima after the end of the voltage pulse and the densities of O(P), H and OH radicals and the maximal gas temperature increase as the equivalence ratio increases. We have shown that the production of radicals is the highest on the discharge axis and the distribution of species after the voltage pulse and up to 100 ns has a larger diameter between the electrodes than close to both electrode tips. As for species, the temperature distribution presents two hot spots close to the point electrode tips. The non
15. Measurement of the C2H2 destruction kinetics by infrared laser absorption spectroscopy in a pulsed low pressure dc discharge
International Nuclear Information System (INIS)
Rousseau, A; Guaitella, O; Gatilova, L; Hannemann, M; Roepcke, J
2007-01-01
The kinetics of destruction of C 2 H 2 is investigated in a low pressure pulsed dc discharge in dry air. Tuneable diode laser absorption spectroscopy in the mid-infrared region (1350 cm -1 ) has been used to measure the influence of (i) the pulse duration (ii) the pulse repetition rate and (iii) the pulse current on the C 2 H 2 concentration in situ the discharge tube. First, it is shown that in the plasma region under flow conditions the time averaged concentration of C 2 H 2 depends only on the time averaged discharge current. Second, time resolved measurements have been performed in a closed reactor, i.e. under static conditions. A simple kinetic modelling of the pulsed discharge leads to a good agreement with the experimental results and shows that the oxidation rate of C 2 H 2 is mainly controlled by the time averaged concentration of O atoms. Finally, the influence of porous TiO 2 photocatalyst on the C 2 H 2 oxidation rate is reported
16. Influence of excited state spatial distributions on plasma diagnostics: Atmospheric pressure laser-induced He-H2 plasma
Science.gov (United States)
Monfared, Shabnam K.; Hüwel, Lutz
2012-10-01
Atmospheric pressure plasmas in helium-hydrogen mixtures with H2 molar concentrations ranging from 0.13% to 19.7% were investigated at times from 1 to 25 μs after formation by a Q-switched Nd:YAG laser. Spatially integrated electron density values are obtained using time resolved optical emission spectroscopic techniques. Depending on mixture concentration and delay time, electron densities vary from almost 1017 cm-3 to about 1014 cm-3. Helium based results agree reasonably well with each other, as do values extracted from the Hα and Hβ emission lines. However, in particular for delays up to about 7 μs and in mixtures with less than 1% hydrogen, large discrepancies are observed between results obtained from the two species. Differences decrease with increasing hydrogen partial pressure and/or increasing delay time. In mixtures with molecular hydrogen fraction of 7% or more, all methods yield electron densities that are in good agreement. These findings seemingly contradict the well-established idea that addition of small amounts of hydrogen for diagnostic purposes does not perturb the plasma. Using Abel inversion analysis of the experimental data and a semi-empirical numerical model, we demonstrate that the major part of the detected discrepancies can be traced to differences in the spatial distributions of excited helium and hydrogen neutrals. The model yields spatially resolved emission intensities and electron density profiles that are in qualitative agreement with experiment. For the test case of a 1% H2 mixture at 5 μs delay, our model suggests that high electron temperatures cause an elevated degree of ionization and thus a reduction of excited hydrogen concentration relative to that of helium near the plasma center. As a result, spatially integrated analysis of hydrogen emission lines leads to oversampling of the plasma perimeter and thus to lower electron density values compared to those obtained from helium lines.
17. Simulation and optical spectroscopy of a DC discharge in a CH4/H2/N2 mixture during deposition of nanostructured carbon films
Science.gov (United States)
Mironovich, K. V.; Mankelevich, Yu. A.; Voloshin, D. G.; Dagesyan, S. A.; Krivchenko, V. A.
2017-08-01
Two-dimensional numerical simulations of a dc discharge in a CH4/H2/N2 mixture in the regime of deposition of nanostructured carbon films are carried out with account of the cathode electron beam effects. The distributions of the gas temperature and species number densities are calculated, and the main plasmachemical kinetic processes governing the distribution of methyl radicals above the substrate are analyzed. It is shown that the number density of methyl radicals above the substrate is several orders of magnitude higher than the number densities of other hydrocarbon radicals, which indicates that the former play a dominant role in the growth of nanostructured carbon films. The model is verified by comparing the measured optical emission profiles of the H( n ≡ 3), C 2 * , CH*, and CN* species and the calculated number densities of excited species, as well as the measured and calculated values of the discharge voltage and heat fluxes onto the electrodes and reactor walls. The key role of ion-electron recombination and dissociative excitation of H2, C2H2, CH4, and HCN molecules in the generation of emitting species (first of all, in the cold regions adjacent to the electrodes) is revealed.
18. Hydrogeological controls on spatial patterns of groundwater discharge in peatlands
Directory of Open Access Journals (Sweden)
D. K. Hare
2017-11-01
Full Text Available Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns
19. Hydrogeological controls on spatial patterns of groundwater discharge in peatlands
Science.gov (United States)
Hare, Danielle K.; Boutt, David F.; Clement, William P.; Hatch, Christine E.; Davenport, Glorianna; Hackman, Alex
2017-11-01
Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns may allow resource
20. Experimental study of spatial distribution of Ar glow discharge plasma
International Nuclear Information System (INIS)
Guo, X.M.; Zhou, T.D.; Pai, S.T.
1996-01-01
The characteristics of the spatial distribution of Ar glow discharge plasma were experimentally investigated. By means of direct comparisons between theory and experiment, the effects of the variation of gap separation, gas pressure, and electrode radius on the spatial distributions of electron density and electric field were studied. Results indicate that the maximum electron density moves toward the cathode as the gap separation or gas pressure increases while variation of electrode radius produces little effect. Predictions from a theoretical model have been experimentally verified. General agreements between theory and experiment were found to be reasonably good except in the cathode region, where discrepancy exists. copyright 1996 American Institute of Physics
1. [Gas chromatography with a Pulsed discharge helium ionization detector for measurement of molecular hydrogen(H2) in the atmosphere].
Science.gov (United States)
Luan, Tian; Fang, Shuang-xi; Zhou, Ling-xi; Wang, Hong-yang; Zhang, Gen
2015-01-01
A high precision GC system with a pulsed discharge helium ionization detector was set up based on the commercial Agilent 7890A gas chromatography. The gas is identified by retention time and the concentration is calculated through the peak height. Detection limit of the system is about 1 x 10(-9) (mole fraction, the same as below). The standard deviation of 140 continuous injections with a standard cylinder( concentration is roughly 600 x 10(-9)) is better than 0.3 x 10(-9). Between 409.30 x 10(-9) and 867.74 x 10(-9) molecular hydrogen mole fractions and peak height have good linear response. By using two standards to quantify the air sample, the precision meets the background molecular hydrogen compatibility goal within the World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) program. Atmospheric molecular hydrogen concentration at Guangzhou urban area was preliminarily measured by this method from January to November 2013. The results show that the atmospheric molecular hydrogen mole fraction varies from 450 x 10(-9) to 700 x 10(-9) during the observation period, with the lowest value at 14:00 (Beijing time, the same as below) and the peak value at 20:00. The seasonal variation of atmospheric hydrogen at Guangzhou area was similar with that of the same latitude stations in northern hemisphere.
2. Seasonal formation of ikaite (caco 3 · 6h 2o) in saline spring discharge at Expedition Fiord, Canadian High Arctic: Assessing conditional constraints for natural crystal growth
Science.gov (United States)
Omelon, Christopher R.; Pollard, Wayne H.; Marion, Giles M.
2001-05-01
- Spring discharge at Expedition Fiord (Pollard et al., 1999) on Axel Heiberg Island in the Canadian High Arctic produces a variety of travertine forms in addition to a diverse collection of mineral precipitates. This paper focuses on clusters of thermally unstable crystals believed to be the mineral ikaite (CaCO 3 · 6H 2O) growing seasonally along two spring outflows at Colour Peak. This form of calcium carbonate mineral occurs along small sections of discharge outflow as white euhedral crystals up to 0.5 cm in length. Difficulty in sampling, storage and transport of the samples for analysis has hampered attempts to confirm the presence of ikaite by X-ray diffraction. However, various field observations and the remarkable instability of these crystals at normal ambient temperatures strengthens our argument. This paper provides a description of these particular CaCO 3 · 6H 2O crystals and their environmental surroundings, and attempts to determine the validity of ikaite precipitation at this site by theoretical geochemical modeling: these results are compared with other reported observations of ikaite to both understand their occurrence and help delineate their geochemical characteristics. It is believed that the restrictive combination of spring water chemistry and long periods of low temperatures characteristic of arctic climates are necessary for ikaite growth at this site. The fact that ikaite is not forming at a second group of saline springs 11 km away allows us to more specifically outline conditions controlling its presence.
3. + H2
Indian Academy of Sciences (India)
(1D. ) + H2 (v = 0, j = 0) →. OH + H is undertaken using the quasiclassical trajectory (QCT) method for the collision energy is in the large length of 1.3 to 43 kcal/mol using Dobbyn and Knowles (DK) surface, and the obtained results are compared with those available from earlier available calculated results on the BR surface ...
4. Kinetics of NO formation and decay in nanosecond pulse discharges in Air, H2-Air, and C2H4-Air mixtures
International Nuclear Information System (INIS)
Burnette, David; Shkurenkov, Ivan; Adamovich, Igor V; Lempert, Walter R
2016-01-01
Time-resolved, absolute NO and N atom number densities are measured by NO Laser Induced Fluorescence (LIF) and N Two-Photon Absorption LIF in a diffuse plasma filament, nanosecond pulse discharge in dry air, hydrogen-air, and ethylene-air mixtures at 40 Torr, over a wide range of equivalence ratios. The results are compared with kinetic modeling calculations incorporating pulsed discharge dynamics, kinetics of vibrationally and electronically excited states of nitrogen, plasma chemical reactions, and radial transport. The results show that in air afterglow, NO decay occurs primarily by the reaction with N atoms, NO + N → N 2 + O. In the presence of hydrogen, this reaction is mitigated by reaction of N atoms with OH, N + OH → NO + H, resulting in significant reduction of N atom number density in the afterglow, additional NO production, and considerably higher NO number densities. In fuel-lean ethylene-air mixtures, a similar trend (i.e. N atom concentration reduction and NO number density increase) is observed, although [NO] increase on ms time scale is not as pronounced as in H 2 -air mixtures. In near-stoichiometric and fuel-lean ethylene-air mixtures, when N atom number density was below detection limit, NO concentration was measured to be lower than in air plasma. These results suggest that NO kinetics in hydrocarbon-air plasmas is more complex compared to air and hydrogen-air plasmas, additional NO reaction pathways may well be possible, and their analysis requires further kinetic modeling calculations. (paper)
5. Observations on the spatial variability of the Prut river discharges
Directory of Open Access Journals (Sweden)
Emil-Andrei BRICIU
2011-06-01
Full Text Available Liquid and solid discharges of the Prut River were analysed based on measurementsperformed in 7 points from the Romanian national network of water monitoring during aperiod of 30 years. The analyses were performed on flows for the period after theconstruction of the Stânca-Costeşti dam and show the influence of the dam for the entireanalysed time. The analysis from upstream to downstream of the spatial variability of thePrut River annual discharges showed their steady increase downstream and then adecrease in the sector next to Oancea station. A statistical minority of the annualdischarges showed a continuous increase of them until the flowing of Prut into Danube.Knowing that the lower basin of the river is characterized by a low amount of rainfall anda higher evapo(transpiration than the remaining basin, the decreasing flows to the rivermouth is explicable; but the increasing flows to the river mouth cannot be justified, underthese conditions of water balance, than by certain climatological parameters of thermodynamicalnature which generate, with increased frequency, more intense and rich rainfall, with a torrential character. The analyses on couples of three months showed thatthe Oancea flows are higher than the upstream stations (opposite than usual in yearswhen the flows of the upstream hydrometrical stations are lower than the multiannualaverage and that supports the mentioned pluviometrical character. A plausible cause for"Oancea phenomenon" is the increase and the decrease of the sunspots number, whosecycles are relatively well fold on the increase and decrease of annual average flow atOancea hydrometrical station. The strongest increased discharges of the Prut River overthe discharges at the upstream stations occur from May to July (MJJ, the months with thehighest amount of rainfall. Seasonal analysis of MJJ and other couples of 3 monthsshowed that there are also growing flows at Prisăcani station relative to the adjacentstations, but
6. The effect of axial ion parameters on the properties of glow discharge polymer in T2B/H2 plasma
Science.gov (United States)
Ai, Xing; He, Xiao-Shan; Huang, Jing-Lin; He, Zhi-Bing; Du, Kai; Chen, Guo
2018-03-01
Glow discharge polymer (GDP) films were fabricated using plasma-enhanced chemical vapor deposition. The main purpose of this work was to explore the correlations of plasma parameters with the surface morphology and chemical structure of GDP films. The intensities of main positive ions and ion energy as functions of axial distances in T2B/H2 plasma were diagnosed using energy-resolved mass spectrometry. The surface morphology and chemical structure were characterized as functions of axial distances using a scanning electron microscope and Fourier transform infrared spectroscopy, respectively. As the axial distance increases, both the intensities of positive ions and high energy ions decreases, and dissociation weakens while polymerization enhances. This leads to the weakening of the cross-linking structure of GDP films and the formation of dome defects on films. Additionally, high energy ions could introduce a strong etching effect to form etching pits. Therefore, an axial distance of about 20 mm was found to be the optimal plasma parameter to prepare the defect-free GDP films. These results could help one to find the optimal plasma parameters for GDP film deposition.
7. Observations of different core water cluster ions Y-(H2O)n (Y = O2, HOx, NOx, COx) and magic number in atmospheric pressure negative corona discharge mass spectrometry.
Science.gov (United States)
Sekimoto, Kanako; Takayama, Mitsuo
2011-01-01
Reliable mass spectrometry data from large water clusters Y(-)(H(2)O)(n) with various negative core ions Y(-) such as O(2)(-), HO(-), HO(2)(-), NO(2)(-), NO(3)(-), NO(3)(-)(HNO(3))(2), CO(3)(-) and HCO(4)(-) have been obtained using atmospheric pressure negative corona discharge mass spectrometry. All the core Y(-) ions observed were ionic species that play a central role in tropospheric ion chemistry. These mass spectra exhibited discontinuities in ion peak intensity at certain size clusters Y(-)(H(2)O)(m) indicating specific thermochemical stability. Thus, Y(-)(H(2)O)(m) may correspond to the magic number or first hydrated shell in the cluster series Y(-)(H(2)O)(n). The high intensity discontinuity at HO(-)(H(2)O)(3) observed was the first mass spectrometric evidence for the specific stability of HO(-)(H(2)O)(3) as the first hydrated shell which Eigen postulated in 1964. The negative ion water clusters Y(-)(H(2)O)(n) observed in the mass spectra are most likely to be formed via core ion formation in the ambient discharge area (760 torr) and the growth of water clusters by adiabatic expansion in the vacuum region of the mass spectrometers (≈1 torr). The detailed mechanism of the formation of the different core water cluster ions Y(-)(H(2)O)(n) is described. Copyright © 2010 John Wiley & Sons, Ltd.
8. Mapping Submarine Groundwater Discharge - how to investigate spatial discharge variability on coastal and beach scales
Science.gov (United States)
Stieglitz, T. C.; Burnett, W. C.; Rapaglia, J.
2008-12-01
Submarine groundwater discharge (SGD) is now increasingly recognized as an important component in the water balance, water quality and ecology of the coastal zone. A multitude of methods are currently employed to study SGD, ranging from point flux measurements with seepage meters to methods integrating over various spatial and temporal scales such as hydrological models, geophysical techniques or surface water tracer approaches. From studies in a large variety of hydrogeological settings, researchers in this field have come to expect that SGD is rarely uniformly distributed. Here we discuss the application of: (a) the mapping of subsurface electrical conductivity in a discharge zone on a beach; and (b) the large-scale mapping of radon in coastal surface water to improving our understanding of SGD and its spatial variability. On a beach scale, as part of intercomparison studies of a UNESCO/IAEA working group, mapping of subsurface electrical conductivity in a beach face have elucidated the non-uniform distribution of SGD associated with rock fractures, volcanic settings and man-made structures (e.g., piers, jetties). Variations in direct point measurements of SGD flux with seepage meters were linked to the subsurface conductivity distribution. We demonstrate how the combination of these two techniques may complement one another to better constrain SGD measurements. On kilometer to hundred kilometer scales, the spatial distribution and regional importance of SGD can be investigated by mapping relevant tracers in the coastal ocean. The radon isotope Rn-222 is a commonly used tracer for SGD investigations due to its significant enrichment in groundwater, and continuous mapping of this tracer, in combination with ocean water salinity, can be used to efficiently infer locations of SGD along a coastline on large scales. We use a surface-towed, continuously recording multi-detector setup installed on a moving vessel. This tool was used in various coastal environments, e
9. Spatially and Temporally Resolved Measurements of Velocity in a H2-air Combustion-Heated Supersonic Jet
Science.gov (United States)
Bivolaru, Daniel; Cutler, Andrew D.; Danehy, Paul M.; Gaffney, Richard L.; Baurle, Robert a.
2009-01-01
This paper presents simultaneous measurements at multiple points of two orthogonal components of flow velocity using a single-shot interferometric Rayleigh scattering (IRS) technique. The measurements are performed on a large-scale Mach 1.6 (Mach 5.5 enthalpy) H2-air combustion jet during the 2007 test campaign in the Direct Connect Supersonic Combustion Test facility at NASA Langley Research Center. The measurements are performed simultaneously with CARS (Coherent Anti-stokes Raman Spectroscopy) using a combined CARS-IRS instrument with a common path 9-nanosecond pulsed, injection-seeded, 532-nm Nd:YAG laser probe pulse. The paper summarizes the measurements of velocities along the core of the vitiated air flow as well as two radial profiles. The average velocity measurement near the centerline at the closest point from the nozzle exit compares favorably with the CFD calculations using the VULCAN code. Further downstream, the measured axial velocity shows overall higher values than predicted with a trend of convergence at further distances. Larger discrepancies are shown in the radial profiles.
10. Variability of O2, H2S, and pH in intertidal sediments measured on a highly resolved spatial and temporal scale
Science.gov (United States)
Walpersdorf, E.; Werner, U.; Bird, P.; de Beer, D.
2003-04-01
We investigated the variability of O_2, pH, and H_2S in intertidal sediments to assess the time- and spatial scales of changes in environmental conditions and their effects on bacterial activities. Measurements were performed over the tidal cycle and at different seasons by the use of microsensors attached to an autonomous in-situ measuring device. This study was carried out at a sand- and a mixed flat in the backbarrier area of Spiekeroog (Germany) within the frame of the DFG research group "Biogeochemistry of the Wadden Sea". Results showed that O_2 variability was not pronounced in the coastal mixed flat, where only extreme weather conditions could increase O_2 penetration. In contrast, strong dynamics in O_2 availability, pH and maximum penetration depths of several cm were found at the sandflat. In these highly permeable sediments, we directly observed tidal pumping: at high tide O_2-rich water was forced into the plate and at low tide anoxic porewater drained off the sediment. From the lower part of the plate where organic rich clayey layers were embedded in the sediment anoxic water containing H_2S leaked out during low tide. Thus advective processes, driven by the tidal pump, waves and currents, control O_2 penetration and depth distribution of H_2S and pH. The effects of the resulting porewater exchange on mineralization rates and microbial activities will be discussed.
11. H2 blockers
Science.gov (United States)
Peptic ulcer disease - H2 blockers; PUD - H2 blockers; Gastroesophageal reflux - H2 blockers; GERD - H2 blockers ... H2 blockers are used to: Relieve symptoms of acid reflux, or gastroesophageal reflux disease (GERD). This is a ...
12. Spatial Characteristics and Driving Factors of Provincial Wastewater Discharge in China.
Science.gov (United States)
Chen, Kunlun; Liu, Xiaoqiong; Ding, Lei; Huang, Gengzhi; Li, Zhigang
2016-12-09
Based on the increasing pressure on the water environment, this study aims to clarify the overall status of wastewater discharge in China, including the spatio-temporal distribution characteristics of wastewater discharge and its driving factors, so as to provide reference for developing "emission reduction" strategies in China and discuss regional sustainable development and resources environment policies. We utilized the Exploratory Spatial Data Analysis (ESDA) method to analyze the characteristics of the spatio-temporal distribution of the total wastewater discharge among 31 provinces in China from 2002 to 2013. Then, we discussed about the driving factors, affected the wastewater discharge through the Logarithmic Mean Divisia Index (LMDI) method and classified those driving factors. Results indicate that: (1) the total wastewater discharge steadily increased, based on the social economic development, with an average growth rate of 5.3% per year; the domestic wastewater discharge is the main source of total wastewater discharge, and the amount of domestic wastewater discharge is larger than the industrial wastewater discharge. There are many spatial differences of wastewater discharge among provinces via the ESDA method. For example, provinces with high wastewater discharge are mainly the developed coastal provinces such as Jiangsu Province and Guangdong Province. Provinces and their surrounding areas with low wastewater discharge are mainly the undeveloped ones in Northwest China; (2) The dominant factors affecting wastewater discharge are the economy and technological advance; The secondary one is the efficiency of resource utilization, which brings about the unstable effect; population plays a less important role in wastewater discharge. The dominant driving factors affecting wastewater discharge among 31 provinces are divided into three types, including two-factor dominant type, three-factor leading type and four-factor antagonistic type. In addition, the
13. Temporal symmetry of individual filaments in different spatial symmetry filaments pattern in a dielectric barrier discharge
International Nuclear Information System (INIS)
Dong, L. F.; Xiao, H.; Fan, W. L.; Yin, Z. Q.; Zhao, H. T.
2010-01-01
The temporal behavior of individual filament in different spatial symmetry filaments patterns in dielectric barrier discharge is investigated by using an optical method. A series of return maps of the discharge moments of individual filaments is given. It is found that the temporal symmetry of individual filament changes with the change of the spatial symmetry of filaments pattern as the applied voltage increases. The role of wall charges for this phenomenon is analyzed.
14. Synthesis, Spatial Structure and Analgesic Activity of Sodium 3-Benzylaminocarbonyl-1-methyl-2,2-dioxo-1H-2λ6,1-benzothiazin-4-olate Solvates
Directory of Open Access Journals (Sweden)
Igor V. Ukrainets
2016-10-01
Full Text Available In order to obtain and then test pharmocologically any possible conformers of the new feasible analgesic N-benzyl-4-hydroxy-1-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamide, its 4-O-sodium salt was synthesized using two methods. X-ray diffraction study made possible to determine that, depending on the chosen synthesis conditions, the above-mentioned compound forms either monosolvate with methanol or monohydrate, where organic anion exists in the form of three different conformers. Pharmacological testing of the two known pseudo-enantiomeric forms of the original N-benzylamide and of the two solvates of its sodium salt was performed simultaneously under the same conditions and in equimolar doses. Comparison of the results obtained while studying the peculiarities of the synthesized compounds spatial structure and biological properties revealed an important structure-action relationship. In particular, it was shown that the intensity of analgesic effect of different conformational isomers of N-benzyl-4-hydroxy-1-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamide may change considerably: while low active conformers are comparable with piroxicam, highly active conformers are more than twice as effective as meloxicam.
15. Combined effect of electrode gap and radio frequency on power deposition and film growth kinetics in SiH4/H2 discharges
International Nuclear Information System (INIS)
Amanatides, E.; Mataras, D.; Rapakoulias, D.E.
2002-01-01
The combined effect of the variation of the interelectrode gap (1.3-2.5 cm) and radio frequency (13.56-50 MHz) on the properties of highly diluted silane in hydrogen discharges used for the deposition of microcrystalline silicon thin films is presented. The investigation included electrical and optical discharge measurements as well as the in situ determination of the film growth rate. In the lower frequencies regime, the increase of the interelectrode gap for the same applied voltage results in higher current flows and higher total power dissipation. On the other hand, at 50 MHz the variation of the interelectrode space has only a slight effect on the total power dissipation, due to the low excitation voltage. However, at all frequencies, the increase of the interelectrode space results in a drop of the power dissipation per discharge volume. This is related to the less effective energy transfer to the electrons that is due to the enhancement of the bulk relative to the sheath ohmic heating. The variation of the relative importance of the electron heating modes is reflected in the discharge radical production efficiency and the film growth rate
16. Time-dependent one-dimensional simulation of atmospheric dielectric barrier discharge in N2/O2/H2O using COMSOL Multiphysics
Science.gov (United States)
Sohbatzadeh, F.; Soltani, H.
2018-04-01
The results of time-dependent one-dimensional modelling of a dielectric barrier discharge (DBD) in a nitrogen-oxygen-water vapor mixture at atmospheric pressure are presented. The voltage-current characteristics curves and the production of active species are studied. The discharge is driven by a sinusoidal alternating high voltage-power supply at 30 kV with frequency of 27 kHz. The electrodes and the dielectric are assumed to be copper and quartz, respectively. The current discharge consists of an electrical breakdown that occurs in each half-period. A detailed description of the electron attachment and detachment processes, surface charge accumulation, charged species recombination, conversion of negative and positive ions, ion production and losses, excitations and dissociations of molecules are taken into account. Time-dependent one-dimensional electron density, electric field, electric potential, electron temperature, densities of reactive oxygen species (ROS) and reactive nitrogen species (RNS) such as: O, O-, O+, {O}2^{ - } , {O}2^{ + } , O3, {N}, {N}2^{ + } , N2s and {N}2^{ - } are simulated versus time across the gas gap. The results of this work could be used in plasma-based pollutant degradation devices.
17. H2@Scale Analysis
Energy Technology Data Exchange (ETDEWEB)
Ruth, Mark
2017-07-12
'H2@Scale' is a concept based on the opportunity for hydrogen to act as an intermediate between energy sources and uses. Hydrogen has the potential to be used like the primary intermediate in use today, electricity, because it too is fungible. This presentation summarizes the H2@Scale analysis efforts performed during the first third of 2017. Results of technical potential uses and supply options are summarized and show that the technical potential demand for hydrogen is 60 million metric tons per year and that the U.S. has sufficient domestic resources to meet that demand. A high level infrastructure analysis is also presented that shows an 85% increase in energy on the grid if all hydrogen is produced from grid electricity. However, a preliminary spatial assessment shows that supply is sufficient in most counties across the U.S. The presentation also shows plans for analysis of the economic potential for the H2@Scale concept. Those plans involve developing supply and demand curves for potential hydrogen generation options and as compared to other options for use of that hydrogen.
18. Development of a spatially uniform fast ionization wave in a large-volume discharge
International Nuclear Information System (INIS)
Zatsepin, D.V.; Starikovskaya, S.M.; Starikovskii, A.Yu.
1998-01-01
A study is made of a high-voltage nanosecond breakdown in the form of a fast ionization wave produced in a large-volume (401) discharge chamber. The propagation speed of the wave front and the integral energy deposition in a plasma are measured for various regimes of the air discharge at pressures of 10 -2 -4 Torr. A high degree of both the spatial uniformity of the discharge and the reproducibility of the discharge parameters is obtained. The possibility of the development of a fast ionization wave in an electrodeless system is demonstrated. A transition of the breakdown occurring in the form of a fast ionization wave into the streamer breakdown is observed. It is shown that such discharges are promising for technological applications
19. Spatial Characteristics of Geothermal Spring Temperatures and Discharge Rates in the Tatun Volcanic Area, Taiwan
Science.gov (United States)
Jang, C. S.; Liu, C. W.
2014-12-01
The Tatun volcanic area is the only potential volcanic geothermal region in the Taiwan island, and abundant in hot spring resources owing to stream water mixing with fumarolic gases. According to the Meinzer's classification, spring temperatures and discharge rates are the most important properties for characterizing spring classifications. This study attempted to spatially characterize spring temperatures and discharge rates in the Tatun volcanic area, Taiwanusing indicator kriging (IK). First, data on spring temperatures and discharge rates, which were collected from surveyed data of the Taipei City Government, were divided into high, moderate and low categories according to spring classification criteria, and the various categories were regarded as estimation thresholds. Then, IK was adopted to model occurrence probabilities of specified temperatures and discharge rates in springs, and to determine their classifications based on estimated probabilities. Finally, nine combinations were obtained from the classifications of temperatures and discharge rates in springs. Moreover, the combinations and features of spring water were spatially quantified according to seven sub-zones of spring utilization. A suitable and sustainable development strategy of the spring area was proposed in each sub-zone based on probability-based combinations and features of spring water.The research results reveal that the probability-based classifications using IK provide an excellent insight in exploring the uncertainty of spatial features in springs, and can provide Taiwanese government administrators with detailed information on sustainable spring utilization and conservation in the overexploited spring tourism areas. The sub-zones BT (Beitou), RXY (Rd. Xingyi), ZSL (Zhongshanlou) and LSK (Lengshuikeng) with high or moderate discharge rates are suitable to supply spring water for tourism hotels.Local natural hot springs should be planned in the sub-zones DBT (Dingbeitou), ZSL, XYK
20. Spatial and temporal evolution of microdischarges in Surface Dielectric Barrier Discharges for aeronautical applications plasmas
International Nuclear Information System (INIS)
Barni, R; Biganzoli, I; Riccardi, C
2014-01-01
Surface Dielectric Barrier Discharges have been proposed long ago as a tool to improve aerodynamics and flow performances. Such electrical discharges could be employed to energize the gas phase and to induce flows. The discharge itself consists of a large number of repetitions of single electric current pulses, with short duration and limited spatial extension filling the region near electrodes. The connection between such macroscopic effect and the properties of the single microdischarge events has been investigated. In particular we have measured the direction and the velocity of propagation of the ionization wave during the different phases of the voltage cycle. Light collected from different parts of the gap arrives at a photomultiplier tube with a delay proportional to the velocity of the ionization wave. The measured propagation velocity was estimated as about 220 km/s in the so called backward discharge phase
1. Aqueous-phase chemistry and bactericidal effects from an air discharge plasma in contact with water: Evidence for the formation of peroxynitrite through a pseudo-second-order post-discharge reaction of H2O2 and HNO2
Czech Academy of Sciences Publication Activity Database
Lukeš, Petr; Doležalová, Eva; Sisrová, Irena; Člupek, Martin
2014-01-01
Roč. 23, č. 1 (2014), 015019-015019 ISSN 0963-0252 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431203 Program:M Institutional support: RVO:61389021 Keywords : air discharge plasma * plasma–liquid interactions * peroxynitrite * hydrogen peroxide * phenol * bacteria Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.591, year: 2014 http://iopscience.iop.org/0963-0252/23/1/015019/pdf/0963-0252_23_1_015019.pdf
2. Development of a new corona discharge based ion source for high resolution time-of-flight chemical ionization mass spectrometer to measure gaseous H2SO4 and aerosol sulfate
Science.gov (United States)
Zheng, Jun; Yang, Dongsen; Ma, Yan; Chen, Mindong; Cheng, Jin; Li, Shizheng; Wang, Ming
2015-10-01
A new corona discharge (CD) based ion source was developed for a commercial high-resolution time-of-flight chemical ionization mass spectrometer (HRToF-CIMS) (Aerodyne Research Inc.) to measure both gaseous sulfuric acid (H2SO4) and aerosol sulfate after thermal desorption. Nitrate core ions (NO3-) were used as reagent ions and were generated by a negative discharge in zero air followed by addition of excess nitrogen dioxide (NO2) to convert primary ions and hydroxyl radicals (OH) into NO3- ions and nitric acid (HNO3). The CD-HRToF-CIMS showed no detectable interference from hundreds parts per billion by volume (ppbv) of sulfur dioxide (SO2). Unlike the atmospheric pressure ionization (API) ToF-CIMS, the CD ion source was integrated onto the ion-molecule reaction (IMR) chamber and which made it possible to measure aerosol sulfate by coupling to a filter inlet for gases and aerosols (FIGAERO). Moreover, compared with a quadrupole-based mass spectrometer, the desired HSO4- signal was detected by its exact mass of m/z 96.960, which was well resolved from the potential interferences of HCO3-ṡ(H2O)2 (m/z 97.014) and O-ṡH2OṡHNO3 (m/z 97.002). In this work, using laboratory-generated standards the CD-HRToF-CIMS was demonstrated to be able to detect as low as 3.1 × 105 molecules cm-3 gaseous H2SO4 and 0.5 μg m-3 ammonium sulfate based on 10-s integration time and two times of the baseline noise. The CD ion source had the advantages of low cost and a simple but robust structure. Since the system was non-radioactive and did not require corrosive HNO3 gas, it can be readily field deployed. The CD-HRToF-CIMS can be a powerful tool for both field and laboratory studies of aerosol formation mechanism and the chemical processes that were critical to understand the evolution of aerosols in the atmosphere.
3. Spatial and temporal distributions of toxicity in receiving waters around an oil effluent discharge site
International Nuclear Information System (INIS)
Krause, P.R.
1994-01-01
Distributions of pollutants from a point source discharge within the water column may vary in both time and space. In this study, they examined the spatial and temporal patterns of toxicity from an oil production effluent (produced water) discharge plume using sea urchin fertilization and development bioassays. Specifically, they tested the sensitivity and response patterns of sea urchin gametes and early life stages exposed to receiving waters sampled along a 1 km transact near an active produced water outfall. Fertilization success and development of larvae to the pluteus stage varied significantly with proximity to the outfall, with reduced fertilization and larval development found closer to the outfall. Although estimated toxicity in receiving water samples, based on fertilization success, was variable in time -- perhaps responding to variation in the quantity or make-up of produced water discharges -- the general spatial pattern of toxicity along the sampling transact remained relatively constant. Strong evidence that field toxicity was directly attributable to produced water effluents was provided by sampling the receiving waters while the produced water discharge was not operating. At such a time, no toxicity was found at any of the field sites. Receiving water toxicity data, along with toxicity data from the effluent itself, were used to prepare a ''map'' of effective effluent concentrations along the sampling transect
4. Simulation of spatially dependent excitation rates and power deposition in RF discharges for plasma processing
International Nuclear Information System (INIS)
Kushner, M.J.; Anderson, H.M.; Hargis, P.J.
1985-01-01
In low pressure, radio frequency (RF) discharges of the type used in plasma processing of semiconductor materials, the rate of electron impact excitation and energy transfer processes depends upon both the phase of the RF excitation and position in the discharge. Electron impact collisions create radicals that diffuse or drift to the surfaces of interest where they are adsorbed or otherwise react. To the extent that these radicals have a finite lifetime, their transport time from point of creation to surface of interest is an important parameter. The spatial dependence of the rate of the initial electron impact collisions is therefore also an important parameter. The power that sustains the discharge is coupled into the system by two mechanisms: a high energy e-beam component of the electron distribution resulting from electrons falling through or being accelerated by the sheaths, and by joule heating in the body of the plasma. In this paper, the authors discuss the spatial dependence of excitation rates and the method of power deposition iin RF discharges of the type used for plasma processing
5. Spatial and temporal distribution of Fe(II) and H2O2 during EisenEx, an open ocean mescoscale iron enrichment
NARCIS (Netherlands)
Croot, Peter L.; Laan, Patrick; Nishioka, Jun; Strass, Volker; Cisewski, Boris; Boye, Marie; Timmermans, Klaas R.; Bellerby, Richard G.; Goldson, Laura; Nightingale, Phil; Baar, Hein J.W. de
2005-01-01
Measurements of Fe(II) and H2O2 were carried out in the Atlantic sector of the Southern Ocean during EisenEx, an iron enrichment experiment. Iron was added on three separate occasions, approximately every 8 days, as a ferrous sulfate (FeSO4) solution. Vertical profiles of Fe(II) showed maxima
6. Determination of gas temperature and C2 absolute density in Ar/H2/CH4 microwave discharges used for nanocrystalline diamond deposition from the C2 Mulliken system
International Nuclear Information System (INIS)
Lombardi, G; Benedic, F; Mohasseb, F; Hassouni, K; Gicquel, A
2004-01-01
The spectroscopic characterization of Ar/H 2 /CH 4 discharges suitable for the synthesis of nanocrystalline diamond using the microwave plasma assisted chemical vapour deposition process is reported. The experiments are realized in a moderate-pressure bell jar reactor, where discharges are ignited using a microwave cavity coupling system. The concentration of CH 4 is maintained at 1% and the coupled set of hydrogen concentration/microwave power (MWP) ranges from 2%/500 W to 7%/800 W at a pressure of 200 mbar. Emission spectroscopy and broadband absorption spectroscopy studies are carried out on the C 2 (D I SIGMA + u -CHI I SIGMA + g ) Mulliken system and the C 2 (d 3 Π g -a 3 Π u ) Swan system in order to determine the gas temperature and the C 2 absolute density within the plasma. For this purpose, and since the Swan system is quite well-known, much importance is devoted to the achievement of a detailed simulation of the Mulliken system, which allows the determination of both the rotational temperature and the density of the CHI I SIGMA + g ground state, as well as the rotational temperature of the D I SIGMA + u state, from experimental data. All the experimental values are compared to those predicted by a thermochemical model developed to describe Ar/H 2 /CH 4 microwave discharges under quasi-homogeneous plasma assumption. This comparison shows a reasonable agreement between the values measured from the C 2 Mulliken system, those measured from the C 2 Swan system and that calculated from plasma modelling, especially at low hydrogen concentration/MWP. These consistent results show that the use of the Mulliken system leads to fairly good estimates of the gas temperature and of the C 2 absolute density. The relatively high gas temperatures found for the conditions investigated, typically between 3000 K and 4000 K, are attributed to the low thermal conductivity of argon that may limit thermal losses to the substrate surface and reactor wall. The measured C 2
7. Spatial and temporal evolutions of ozone in a nanosecond pulse corona discharge at atmospheric pressure
Energy Technology Data Exchange (ETDEWEB)
Duten, X; Redolfi, M; Aggadi, N; Vega, A; Hassouni, K, E-mail: duten@lspm.cnrs.fr [LSPM-CNRS UPR 3407, Universite Paris Nord, 90 Avenue J.B. Clement, 93430 Villetaneuse (France)
2011-10-19
This paper deals with the experimental determination of the spatial and temporal evolutions of the ozone concentration in an atmospheric pressure pulsed plasma, working in the nanosecond regime. We observed that ozone was produced in the localized region of the streamer. The ozone transport requires a characteristic time well above the millisecond. The numerical modelling of the streamer expansion confirms that the hydrodynamic expansion of the filamentary discharge region during the streamer propagation does not lead to a significant transport of atomic oxygen and ozone. It appears therefore that only diffusional transport can take place, which requires a characteristic time of the order of 50 ms.
8. Spatial and temporal evolutions of ozone in a nanosecond pulse corona discharge at atmospheric pressure
Science.gov (United States)
Duten, X.; Redolfi, M.; Aggadi, N.; Vega, A.; Hassouni, K.
2011-10-01
This paper deals with the experimental determination of the spatial and temporal evolutions of the ozone concentration in an atmospheric pressure pulsed plasma, working in the nanosecond regime. We observed that ozone was produced in the localized region of the streamer. The ozone transport requires a characteristic time well above the millisecond. The numerical modelling of the streamer expansion confirms that the hydrodynamic expansion of the filamentary discharge region during the streamer propagation does not lead to a significant transport of atomic oxygen and ozone. It appears therefore that only diffusional transport can take place, which requires a characteristic time of the order of 50 ms.
9. Spatial and temporal evolutions of ozone in a nanosecond pulse corona discharge at atmospheric pressure
International Nuclear Information System (INIS)
Duten, X; Redolfi, M; Aggadi, N; Vega, A; Hassouni, K
2011-01-01
This paper deals with the experimental determination of the spatial and temporal evolutions of the ozone concentration in an atmospheric pressure pulsed plasma, working in the nanosecond regime. We observed that ozone was produced in the localized region of the streamer. The ozone transport requires a characteristic time well above the millisecond. The numerical modelling of the streamer expansion confirms that the hydrodynamic expansion of the filamentary discharge region during the streamer propagation does not lead to a significant transport of atomic oxygen and ozone. It appears therefore that only diffusional transport can take place, which requires a characteristic time of the order of 50 ms.
10. Partial discharge signal denoising with spatially adaptive wavelet thresholding and support vector machines
Energy Technology Data Exchange (ETDEWEB)
Mota, Hilton de Oliveira; Rocha, Leonardo Chaves Dutra da [Department of Computer Science, Federal University of Sao Joao del-Rei, Visconde do Rio Branco Ave., Colonia do Bengo, Sao Joao del-Rei, MG, 36301-360 (Brazil); Salles, Thiago Cunha de Moura [Department of Computer Science, Federal University of Minas Gerais, 6627 Antonio Carlos Ave., Pampulha, Belo Horizonte, MG, 31270-901 (Brazil); Vasconcelos, Flavio Henrique [Department of Electrical Engineering, Federal University of Minas Gerais, 6627 Antonio Carlos Ave., Pampulha, Belo Horizonte, MG, 31270-901 (Brazil)
2011-02-15
In this paper an improved method to denoise partial discharge (PD) signals is presented. The method is based on the wavelet transform (WT) and support vector machines (SVM) and is distinct from other WT-based denoising strategies in the sense that it exploits the high spatial correlations presented by PD wavelet decompositions as a way to identify and select the relevant coefficients. PD spatial correlations are characterized by WT modulus maxima propagation along decomposition levels (scales), which are a strong indicative of the their time-of-occurrence. Denoising is performed by identification and separation of PD-related maxima lines by an SVM pattern classifier. The results obtained confirm that this method has superior denoising capabilities when compared to other WT-based methods found in the literature for the processing of Gaussian and discrete spectral interferences. Moreover, its greatest advantages become clear when the interference has a pulsating or localized shape, situation in which traditional methods usually fail. (author)
11. Combining observations of channel network contraction and spatial discharge variation to inform spatial controls on baseflow in Birch Creek, Catskill Mountains, USA
Directory of Open Access Journals (Sweden)
Stephen B. Shaw
2017-08-01
New hydrological insights: For the 31 different sub-channels, baseflow discharge per unit drainage area and per unit stream length were highly variable, even during periods of higher moisture storage when all channels were active. Simple mapping of the active channels would not have recognized these sizable spatial differences in discharge contribution. Previous studies of hydrologic scaling in the Catskills have noted the likelihood of heterogeneity in discharge below a threshold of approximately 3–8 km2. This study provides direct documentation of such heterogeneity at smaller spatial scales. When considering perennial and ephemeral streams, such heterogeneity was not well explained by standard topographic, geologic, or meteorological factors. We suggest the heterogeneity may arise from difficult to map fine-scale variations in subsurface properties.
12. Modelling the effects of spatial and temporal resolution of rainfall and basin model on extreme river discharge
NARCIS (Netherlands)
Booij, Martijn J.
2002-01-01
Important characteristics of an appropriate river basin model, intended to study the effect of climate change on basin response, are the spatial and temporal resolution of the model and the rainfall input. The effects of input and model resolution on extreme discharge of a large river basin are
13. Determination of the spatial characteristics of an RF electrodeless discharge by the method of emission tomography
International Nuclear Information System (INIS)
Denisova, N. V.; Revalde, G.; Skudra, A.
2006-01-01
The spatial distribution of the density of mercury atoms in the 7 3 S state in a spherical RF electrode-less gas-discharge lamp is reconstructed by the method of emission tomography. The local values of the corresponding emission coefficients, which are proportional to the density of mercury atoms in the 7 3 S state, are determined from integral (over the plasma volume) measurements of the lamp radiation at a wavelength of 546.1 nm with the help of an algorithm based on the maximum entropy method. The results obtained show that, for all of the operating modes under study, the profile of the density of mercury atoms in the 7 3 S state has a minimum in the center of the lamp and a maximum near its wall. At a generator current of 100 mA and cold-spot temperature of 41 deg. C, the density of mercury atoms in the 7 3 S state is observed to drop substantially both in the center of the lamp and near its wall, the density in the center being reduced to almost zero. An explanation of this phenomenon is proposed
14. Stratospheric H2O
International Nuclear Information System (INIS)
Ellsaesser, H.W.
1979-01-01
Documentation of the extreme aridity (approx. 3% relative humidity) of the lower stratosphere and the rapid decrease of mixing ratio with height just above the polar tropopause (20-fold in the 1st km) was begun by Dobson et al., (1946) in 1943. They recognized that this extreme and persistent aridity must be dynamically maintained else it would have been wiped out by turbulent diffusion. This led Brewer (1949) to hypothesize a stratospheric circulation in which all air enters through the tropical tropopause where it is freeze dried to a mass mixing ratio of 2 to 3 ppM. This dry air then spreads poleward and descends through the polar tropopauses overpowering upward transport of water vapor by diffusion which would otherwise be permitted by the much warmer temperatures of the polar tropopauses. Questions can indeed be raised as to the absolute magnitudes of stratospheric mixing ratios, the effective temperature of the tropical tropopause cold trap, the reality of winter pole freeze-dry sinks and the representativeness of the available observations suggesting an H 2 O mixing ratio maximum just above the tropical tropopause and a constant mixing ratio from the tropopause to 30 to 35 km. However, no model that better fits all of the available data is available, than does the Brewer (1949) hypothesis coupled with a lower stratosphere winter pole, freeze-dry sink, at least over Antarctica
15. Dissociative charge exchange of H2+
International Nuclear Information System (INIS)
Bruijn, D. de.
1983-01-01
This thesis is devoted to molecular dissociation, in particular the dissociation of the hydrogen molecule H 2 arising from electron capture of its ion H 2 + in a collision. Thereby the important practical question how a chemical bond can be broken is implicitly addressed. This thesis opens (chapter I) with an overview of the available experimental approaches in molecular physics. Further the simple Demkov model for NRCE is described. In chapter II a novel experimental technique for measurements on dissociative processes is introduced which combines a high efficiency with a high energy resolution. A detailed description of the techniques applied in the detector, which has a high spatial and timing resolution with 30 μm and 350 psec FWHM respectively for the detection of one particle, is given in chapter III. A semi-classical theory for NRCE in the medium energy range between a diatomic molecular ion and an atom is developed in chapter IV. The experiments on dissociative charge exchange of H 2 + with Ar, Mg, Na and Cs targets at keV energies are described in Chapter V. The predissociation of the c 3 PIsub(u)-state of H 2 populated after charge exchange of H 2 with several targets at keV energies; is the subject of chapter VI. In chapter VII, orientational oscillations in the cross section for charge exchange of H 2 + with alkali targets are discussed. The last chapter deals with predissociation of highly excited states in H 2 . (Auth.)
16. EPA H2O Software Tool
Science.gov (United States)
EPA H2O allows user to: Understand the significance of EGS in Tampa Bay watershed; visually analyze spatial distribution of the EGS in Tampa Bay watershed; obtain map and summary statistics of EGS values in Tampa Bay watershed; analyze and compare potential impacts of development...
17. Spatial distribution of ozone density in pulsed corona discharges observed by two-dimensional laser absorption method
Energy Technology Data Exchange (ETDEWEB)
Ono, Ryo; Oda, Tetsuji [Department of Electrical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan)
2004-03-07
The spatial distribution of ozone density is measured in pulsed corona discharges with a 40 {mu}m spatial resolution using a two-dimensional laser absorption method. Discharge occurs in a 13 mm point-to-plane gap in dry air with a pulse duration of 100 ns. The result shows that the ozone density increases for about 100 {mu}s after the discharge pulse. The rate coefficient of the ozone-producing reaction, O + O{sub 2} + M {yields} O{sub 3} + M, is estimated to be 3.5 x 10{sup -34} cm{sup 6} s{sup -1}. It is observed that ozone is mostly distributed in the secondary-streamer channel. This suggests that most of the ozone is produced by the secondary streamer, not the primary streamer. After the discharge pulse, ozone diffuses into the background from the secondary-streamer channel. The diffusion coefficient of ozone is estimated to be approximately 0.1 to 0.2 cm{sup 2} s{sup -1}.
18. Spatial distribution of ozone density in pulsed corona discharges observed by two-dimensional laser absorption method
International Nuclear Information System (INIS)
Ono, Ryo; Oda, Tetsuji
2004-01-01
The spatial distribution of ozone density is measured in pulsed corona discharges with a 40 μm spatial resolution using a two-dimensional laser absorption method. Discharge occurs in a 13 mm point-to-plane gap in dry air with a pulse duration of 100 ns. The result shows that the ozone density increases for about 100 μs after the discharge pulse. The rate coefficient of the ozone-producing reaction, O + O 2 + M → O 3 + M, is estimated to be 3.5 x 10 -34 cm 6 s -1 . It is observed that ozone is mostly distributed in the secondary-streamer channel. This suggests that most of the ozone is produced by the secondary streamer, not the primary streamer. After the discharge pulse, ozone diffuses into the background from the secondary-streamer channel. The diffusion coefficient of ozone is estimated to be approximately 0.1 to 0.2 cm 2 s -1
19. Full spatial-field visualization of gas temperature in an air micro-glow discharge by calibrated Schlieren photography
Science.gov (United States)
Xiong, Qing; Xu, Le; Wang, Xia; Xiong, Lin; Huang, Qinghua; Chen, Qiang; Wang, Jingang; Peng, Wenxiong; Li, Jiarui
2018-03-01
Gas temperature is an important basic parameter for both fundamental research and applications of plasmas. In this work, efforts were made to visualize the full spatial field of gas temperature (T g) in a microdischarge with sharp T g gradients by a method of calibrated Schlieren (CS) photography. Compared to other two typical diagnostic approaches, optical emission spectroscopy (OES) and Rayleigh scattering, the proposed CS method exhibits the ability to capture the whole field of gas temperature using a single Schlieren image, even the discharge is of non-luminous zones like Faraday dark space (FDS). The image shows that the T g field in the studied micro-glow air discharge expands quickly with the increase of discharge currents, especially in the cathode region. The two-dimensional maps of gas temperature display a ‘W-shape’ with sharp gradients in both areas of negative and positive glows, slightly arched distributions in the positive column, and cooling zones in the FDS. The obtained T g fields show similar patterns to that of the discharge luminance. With an increase in discharge currents, more electric energy is dissipated by heating air gas and inducing constriction of the low-temperature FDS. Except in the vicinities of electrode boundaries, due to the interference from optical diffraction, the estimated gas temperature distributions are of acceptable accuracy, confirmed by the approaches of OES and UV Rayleigh scattering.
20. Dissociative phototionization cross sections of H2, SO2 and H2O
International Nuclear Information System (INIS)
Chung, Y.
1989-01-01
The partial photoionization cross sections of H 2 , SO 2 , and H 2 O were calculated from the measured photoionization branching ratios and the known total photoionization cross sections. The branching ratios were measured with a time-of-flight mass spectrometer and synchrotron radiation. The branching ratios Of H 2 , SO 2 , and H 2 O were measured for 100 ∼ 410, 150 ∼ 380 and 120 ∼ 720 angstrom. The author also measured the photoionization yield Of SO 2 from 520 to 665 angstrom using a double ion chamber and a glow discharge light source. The principle of a time-of-flight mass spectrometer is explained. New calculations were made to see how the design of the mass spectrometer, applied voltage, and kinetic energy of the ions affect the overall performance of the mass spectrometer. Several useful techniques that we used at the synchrotron for wavelength calibration and higher order suppression are also discussed
1. Investigation of the change in CdxHg1-xTe surface chemical structure under processing in N2O and H2 gases activated by a high-frequency discharge
International Nuclear Information System (INIS)
Vasil'ev, V.V.; Zakhar'yash, T.I.; Kesler, V.G.; Parm, I.O.; Solov'ev, A.P.
2001-01-01
The change in Cd x Hg 1-x Te (CTM) surface chemical composition is investigated during the processing by atomic beams of oxygen and hydrogen, obtained by a method of the electronic impact in a high-frequency plasma (N 2 O and H 2 ). The analysis is carried out using methods of Auger electron spectroscopy and X-ray photoelectron spectroscopy. It is shown that consecutive treatment by beams of atomic oxygen and hydrogen results in removing from the sample surface as carbon impurities so a layer of as-grown oxide and metallic tellurium. It is concluded that the suggested technique of CTM substrate surface pretreatment can be used efficiently in manufacturing semiconductor junctions [ru
2. Temporal and spatial responses of the bioindicator Fucus to discharges of 99Tc in the eastern Irish Sea
International Nuclear Information System (INIS)
McDonald, P.; Busby, R.G.; McCartney, M.
1999-01-01
Technetium-99 is a radioactive isotope discharged under authorisation to the Irish Sea from the British Nuclear Fuels plc Sellafield reprocessing plant in Cumbria via a marine pipeline. An increase in 99 Tc discharges from Sellafield in recent years has provided an ideal opportunity to undertake a more detailed investigation of its environmental behaviour. Here, the temporal and spatial response of Fucus sp. to the increased discharges has been investigated and its role as a bioindicator assessed. Initial investigations in 1995, have confirmed the expectation that Fucus does act as an effective bioindicator of 99 Tc, with easily detectable 99 Tc concentrations (1 - 15 kBq kg -1 wet weight) being encountered, providing a time integrated signal of 99 Tc discharges. Analysis of subsequent samples collected during 1996, however, have shown significant short-term peaks in Fucus 99 Tc concentrations close to Sellafield (up to 90 kBq kg -1 wet weight) and this can be related to peaks in 99 Tc seawater concentrations. This type of response suggests that Fucus has a means of rapidly accumulating 99 Tc, although the rate at which this accumulated component may be eliminated remains unclear. This effect was only observed at sites close to Sellafield (within 15 km). Relatively constant 99 Tc concentrations in Fucus were found at more distant sites (50 - 150 km). (author)
3. Probability-based classifications for spatially characterizing the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region, Taiwan.
Science.gov (United States)
Jang, Cheng-Shin
2015-05-01
Accurately classifying the spatial features of the water temperatures and discharge rates of hot springs is crucial for environmental resources use and management. This study spatially characterized classifications of the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region of Northern Taiwan by using indicator kriging (IK). The water temperatures and discharge rates of the springs were first assigned to high, moderate, and low categories according to the two thresholds of the proposed spring classification criteria. IK was then used to model the occurrence probabilities of the water temperatures and discharge rates of the springs and probabilistically determine their categories. Finally, nine combinations were acquired from the probability-based classifications for the spatial features of the water temperatures and discharge rates of the springs. Moreover, various combinations of spring water features were examined according to seven subzones of spring use in the study region. The research results reveal that probability-based classifications using IK provide practicable insights related to propagating the uncertainty of classifications according to the spatial features of the water temperatures and discharge rates of the springs. The springs in the Beitou (BT), Xingyi Road (XYR), Zhongshanlou (ZSL), and Lengshuikeng (LSK) subzones are suitable for supplying tourism hotels with a sufficient quantity of spring water because they have high or moderate discharge rates. Furthermore, natural hot springs in riverbeds and valleys should be developed in the Dingbeitou (DBT), ZSL, Xiayoukeng (XYK), and Macao (MC) subzones because of low discharge rates and low or moderate water temperatures.
4. Van der Waals bond in dimers: H2Ne, H2Ar, H2Kr
International Nuclear Information System (INIS)
Waaijer, M.
1981-01-01
The H 2 -inert gas dimers H 2 X, and particularly H 2 Ne, H 2 Ar and H 2 Kr, form the subject of this thesis and are loosely bound van der Waals complexes, which is reflected in the low number of bound states and the small anisotropic interaction. The H 2 X dimers studied are formed in a supersonic nozzle expansion, in which the internal energy is converted into the macroscopic flow energy, establishing an internal temperature drop to 3 K, which favours dimer formation. Because of this cooling the H 2 X dimers relax to the lowest rotational states. The hyperfine transitions have been measured using magnetic beam resonance and yield information about the isotropic as well as the anisotropic intermolecular potential in the range between the classical turning points and in the adjacent part of the repulsive branch. The sensitivity of the method is very high and slight changes in the intermolecular potential cause significant effects. The analysis of the measured hyperfine transitions incorporates all interacting states of the molecule, bound as well as unbound (continuum) states. For H 2 Ne, which is the best studied H 2 -inert gas system from the experimental point of view, the author succeeded in establishing an intermolecular potential, that provides a solid ground for comparison with future ab initio calculations. (Auth.)
5. Spatial and temporal variation of repetitive plasma discharges in saline solutions
International Nuclear Information System (INIS)
Stalder, K R; Nersisyan, G; Graham, W G
2006-01-01
Repetitive plasma discharges developed in saline solutions have been investigated using fast, intensified charge coupled detector imaging techniques. The images show that synchronously pulsed multielectrode configurations tend to develop intense, transient plasma regions somewhat randomly in both space and time on short (10 μs) time scales, even though they appear to be stationary on longer (tens of milliseconds) time scales. Evidence for the production of both strongly ionized and weakly ionized plasmas is also presented
6. H2@Scale Workshop Report
Energy Technology Data Exchange (ETDEWEB)
Pivovar, Bryan
2017-03-31
Final report from the H2@Scale Workshop held November 16-17, 2016, at the National Renewable Energy Laboratory in Golden, Colorado. The U.S. Department of Energy's National Renewable Energy Laboratory hosted a technology workshop to identify the current barriers and research needs of the H2@Scale concept. H2@Scale is a concept regarding the potential for wide-scale impact of hydrogen produced from diverse domestic resources to enhance U.S. energy security and enable growth of innovative technologies and domestic industries. Feedback received from a diverse set of stakeholders at the workshop will guide the development of an H2@Scale roadmap for research, development, and early stage demonstration activities that can enable hydrogen as an energy carrier at a national scale.
7. Zeolite encapsulation of H2
International Nuclear Information System (INIS)
Cooper, S.; Lakner, J.F.
1982-08-01
Experiments with H 2 have shown that it is possible to encapsulate gases in the structure of certain molecular sieves. This method may offer a better means of temporarily storing and disposing of tritium over some others presently in use. The method may also prove safer, and may enable isotope separation, and removal of 3 He. Initial experiments were performed with H 2 to screen potential candidates for use with tritium
8. Two-Dimensional Simulation of Spatial-Temporal Behaviors About Period Doubling Bifurcation in an Atmospheric-Pressure Dielectric Barrier Discharge
International Nuclear Information System (INIS)
Zhang Jiao; Wang Yanhui; Wang Dezhen; Zhuang Juan
2014-01-01
As a spatially extended dissipated system, atmospheric-pressure dielectric barrier discharges (DBDs) could in principle possess complex nonlinear behaviors. In order to improve the stability and uniformity of atmospheric-pressure dielectric barrier discharges, studies on temporal behaviors and radial structure of discharges with strong nonlinear behaviors under different controlling parameters are much desirable. In this paper, a two-dimensional fluid model is developed to simulate the radial discharge structure of period-doubling bifurcation, chaos, and inverse period-doubling bifurcation in an atmospheric-pressure DBD. The results show that the period-2n (n = 1, 2…) and chaotic discharges exhibit nonuniform discharge structure. In period-2n or chaos, not only the shape of current pulses doesn't remains exactly the same from one cycle to another, but also the radial structures, such as discharge spatial evolution process and the strongest breakdown region, are different in each neighboring discharge event. Current-voltage characteristics of the discharge system are studied for further understanding of the radial structure. (low temperature plasma)
9. Biogeochemistry of dihydrogen (H2).
Science.gov (United States)
Hoehler, Tori M
2005-01-01
Hydrogen has had an important and evolving role in Earth's geo- and biogeochemistry, from prebiotic to modern times. On the earliest Earth, abiotic sources of H2 were likely stronger than in the present. Volcanic out-gassing and hydrothermal circulation probably occurred at several times the modern rate, due to presumably higher heat flux. The H2 component of volcanic emissions was likely buffered close to the modern value by an approximately constant mantle oxidation state since 3.9 billion years ago, and may have been higher before that, if the early mantle was more reducing. The predominantly ultramafic character of the early, undifferentiated crust could have led to increased serpentinization and release of H2 by hydrothermal circulation, as in modern ultramafic-hosted vents. At the same time, the reactive atmospheric sink for H2 was likely weaker. Collectively, these factors suggest that steady state levels of H2 in the prebiotic atmosphere were 3-4 orders of magnitude higher than at present, and possibly higher still during transient periods following the delivery of Fe and Ni by large impact events. These elevated levels had direct or indirect impacts on the redox state of the atmosphere, the radiation budget, the production of aerosol hazes, and the genesis of biochemical precursor compounds. The early abiotic cycling of H2 helped to establish the environmental and chemical context for the origins of life on Earth. The potential for H2 to serve as a source of energy and reducing power, and to afford a means of energy storage by the establishment of proton gradients, could have afforded it a highly utilitarian role in the earliest metabolic chemistry. Some origin of life theories suggest the involvement of H2 in the first energy-generating metabolism, and the widespread and deeply-branching nature of H2-utilization in the modern tree of life suggests that it was at least a very early biochemical innovation. The abiotic production of H2 via several mechanisms
10. Ebrotidina: nuevo antagonista H2
Directory of Open Access Journals (Sweden)
1999-01-01
Full Text Available Se realizó una revisión bibliográfica sobre un nuevo antagonista H2, la ebrotidina, que exhibe ventajas con respecto a otros medicamentos antisecretores. Las propiedades gastroprotectoras y la actividad anti H. pylori del fármaco, en el tratamiento de la enfermedad péptica ulcerosa, se mencionan en el presente trabajo.A bibliographic review on the new H2 antagonist, ebrotidine, that presents advantages in comparison with other antisecretory drugs, is made. The gastroprotective properties and the anti H. pylori activity of the drug in the treatment of peptic ulcer are mentioned in this paper.
11. Convective model of a microwave discharge in a gas at atmospheric pressure in the form of a spatially localized plasma
International Nuclear Information System (INIS)
Skovoroda, A.A.
1997-01-01
Experiments and a theoretical model consistent with them are presented which show that a stationary microwave discharge in a gas at atmospheric pressure under the action of free convection due to the action of the buoyant force on the heated air can be spatially localized, taking a spheroidal shape. Vortex motion inside the spheroid gives this localized plasma formation some of the properties of a material body which are manifested in a distinct material isolation from the surrounding space, in the formation of a narrow thermal boundary layer and flow separation, and in the formation of secondary vortices in the wake region. The characteristic radius of the stationary localized plasma is governed mainly by the wavelength of the microwave radiation a∼0.137λ. Energy balance is established to a significant degree by convective cooling of the microwave-heated structure
12. Spatial and temporal extension of eutrophication associated with shrimp farm wastewater discharges in the New Caledonia lagoon.
Science.gov (United States)
Thomas, Yoann; Courties, Claude; El Helwe, Yasmin; Herbland, Alain; Lemonnier, Hugues
2010-01-01
Shrimp farming in New Caledonia typically uses a flow-through system with water exchange rates as a tool to maintain optimum hydrological and biological parameters for the crop. Moreover, the effluent shows hydrobiological characteristics (minerals, phytoplankton biomass and organic matter) significantly higher than that of the receiving environment. Separate surveys were carried out in a bay (CH Bay) with a medium-size intensive farm (30 ha) (PO) and in a mangrove-lined creek (TE Creek) near a larger semi-intensive farm (133 ha) (SO). Net loads of nitrogen exported from the semi-intensive farm and the intensive farm amounted to 0.68 and 1.36 kg ha(-1)day(-1), respectively. At CH Bay, discharge effects were spatially limited and clearly restricted to periods of effluent release. The high residence time at site TE favoured the installation of a feedback system in which organic matter was not exported. Mineralization of organic matter led to the release of nutrients, which in turn, caused in an increased eutrophication of this ecosystem. The study of the pico- and nanophytoplankton assemblages showed (i) a shift in composition from picophytoplankton to nanophytoplankton from offshore towards the coast and (ii) a shift within the picophytoplankton with the disappearance of Prochlorococcus and the increase of picoeucaryotes towards the shoreline. These community changes may partially be related to a nitrogen enrichment of the environment by shrimp farm discharges. Thus, in view of the recent addition of the New Caledonian lagoon to the UNESCO World Heritage list, the data presented here could be a first approach to quantify farm discharges and evaluate their impact on the lagoon. Copyright (c) 2010 Elsevier Ltd. All rights reserved.
13. H2@Scale Resource and Market Analysis
Energy Technology Data Exchange (ETDEWEB)
Ruth, Mark
2017-07-12
This presentation overviews progress to date on the H2@Scale resource and market analysis work. The work finds, for example, that hydrogen demand of 60 MMT/yr is possible when transportation and industry are considered; resources are available to meet that demand; using renewable resources would reduce emissions and fossil use by over 15%; further impacts are possible when considering synergistic benefits; additional analysis is underway to improve understanding of potential markets and synergistic impacts; and further analysis will be necessary to estimate impacts due to spatial characteristics, feedback effects in the economy, and inertia characteristics.
14. Angina - discharge
Science.gov (United States)
Chest pain - discharge; Stable angina - discharge; Chronic angina - discharge; Variant angina - discharge; Angina pectoris - discharge; Accelerating angina - discharge; New-onset angina - discharge; Angina-unstable - discharge; ...
15. Spatially hybrid computations for streamer discharges with generic features of pulled fronts: I. Planar fronts
International Nuclear Information System (INIS)
Li Chao; Ebert, Ute; Hundsdorfer, Willem
2010-01-01
Streamers are the first stage of sparks and lightning; they grow due to a strongly enhanced electric field at their tips; this field is created by a thin curved space charge layer. These multiple scales are already challenging when the electrons are approximated by densities. However, electron density fluctuations in the leading edge of the front and non-thermal stretched tails of the electron energy distribution (as a cause of X-ray emissions) require a particle model to follow the electron motion. But present computers cannot deal with all electrons in a fully developed streamer. Therefore, super-particle have to be introduced, which leads to wrong statistics and numerical artifacts. The method of choice is a hybrid computation in space where individual electrons are followed in the region of high electric field and low density while the bulk of the electrons is approximated by densities (or fluids). We here develop the hybrid coupling for planar fronts. First, to obtain a consistent flux at the interface between particle and fluid model in the hybrid computation, the widely used classical fluid model is replaced by an extended fluid model. Then the coupling algorithm and the numerical implementation of the spatially hybrid model are presented in detail, in particular, the position of the model interface and the construction of the buffer region. The method carries generic features of pulled fronts that can be applied to similar problems like large deviations in the leading edge of population fronts, etc.
16. Two-dimensional simulations of multi-hollow VHF SiH4/H2 plasma
Directory of Open Access Journals (Sweden)
Li-Wen Su
2018-02-01
Full Text Available A triode multi-hollow VHF SiH4/H2 plasma (60 MHz was examined at a pressure of 20 Pa by two-dimensional simulations using the fluid model. In this study, we considered the effect of the rate constant of reaction, SiH3 + SiH3→SiH2 + SiH4, on the plasma characteristics. A typical VHF plasma of a high-electron density with a low-electron temperature was obtained between two discharge electrodes. Spatial profiles of SiH3+, SiH2+, SiH3- and SiH3 densities were similar to that of the electron density while the electron temperature had a maximum value near the two discharge electrodes. It was found that the SiH3 radical density did not decrease rapidly near the substrate and the electron temperature was lower than 1 eV, suggesting that the triode multi-hollow plasma source can provide high quality amorphous silicon with a high deposition rate.
17. Spatial-Temporal Variations of Chlorophyll-a in the Adjacent Sea Area of the Yangtze River Estuary Influenced by Yangtze River Discharge
Science.gov (United States)
Wang, Ying; Jiang, Hong; Jin, Jiaxin; Zhang, Xiuying; Lu, Xuehe; Wang, Yueqi
2015-01-01
Carrying abundant nutrition, terrigenous freshwater has a great impact on the spatial and temporal heterogeneity of phytoplankton in coastal waters. The present study analyzed the spatial-temporal variations of Chlorophyll-a (Chl-a) concentration under the influence of discharge from the Yangtze River, based on remotely sensed Chl-a concentrations. The study area was initially zoned to quantitatively investigate the spatial variation patterns of Chl-a. Then, the temporal variation of Chl-a in each zone was simulated by a sinusoidal curve model. The results showed that in the inshore waters, the terrigenous discharge was the predominant driving force determining the pattern of Chl-a, which brings the risk of red tide disasters; while in the open sea areas, Chl-a was mainly affected by meteorological factors. Furthermore, a diversity of spatial and temporal variations of Chl-a existed based on the degree of influences from discharge. The diluted water extended from inshore to the east of Jeju Island. This process affected the Chl-a concentration flowing through the area, and had a potential impact on the marine environment. The Chl-a from September to November showed an obvious response to the discharge from July to September with a lag of 1 to 2 months. PMID:26006121
18. Two-dimensional spatial survey of the plasma potential and electric field in a pulsed bipolar magnetron discharge
International Nuclear Information System (INIS)
Vetushka, A.; Karkari, S.K.; Bradley, J.W.
2004-01-01
Emissive and Langmuir probe techniques have been used to obtain two-dimensional (2D) spatial maps of the plasma potential V p , electric field E, and ion trajectories in a pulsed bipolar magnetron discharge. The magnetron was pulsed at a frequency of 100 kHz, with a 50% duty cycle and operated at an argon pressure of 0.74 Pa. The pulse wave form was characterized by three distinct phases: the 'overshoot', 'reverse', and 'on' phases. In the 'on' phase of the pulse, when the cathode voltage is driven to -670 V, the 2D spatial distribution of V p has a similar form to that in dc magnetron, with significant axial and radial electric fields in the bulk plasma, accelerating ions to the sheath edge above the cathode racetrack region. During the 'overshoot' phase (duration 200 ns), V p is raised to values greater than +330 V, more than 100 V above the cathode potential, with E pointing away from the target. In the 'reverse' phase V p has a value of +45 V at all measured positions, 2 V more positive than the target potential. In this phase there is no electric field present in the plasma. In the bulk of the plasma, the results from Langmuir probe and the emissive probe are in good agreement, however, in one particular region of the plasma outside the radius of the cathode, the emissive probe measurements are consistently more positive (up to 45 V in the 'on' time). This discrepancy is discussed in terms of the different frequency response of the probes and their perturbation of the plasma. A simple circuit model of the plasma-probe system has been proposed to explain our results. A brief discussion of the effect of the changing plasma potential distribution on the operation of the magnetron is given
19. River discharge as a major driving force on spatial and temporal variations in zooplankton biomass and community structure in the Godavari estuary India.
Science.gov (United States)
Venkataramana, V; Sarma, V V S S; Matta Reddy, Alavala
2017-08-28
Variability in horizontal zooplankton biomass distribution was investigated over 13 months in the Godavari estuary, along with physical (river discharge, temperature, salinity), chemical (nutrients, particulate organic matter), biological (phytoplankton biomass), and geological (suspended matter) properties to examine the influencing factors on their spatial and temporal variabilities. The entire estuary was filled with freshwater during peak discharge period and salinity near zero, increased to ~ 34 psu during dry period with relatively high nutrient levels during former than the latter period. Due to low flushing time ( 500 mg L -1 ) during peak discharge period, picoplankton (cyanophyceae) contributed significantly to the phytoplankton biomass (Chl-a) whereas microplankton and nanoplankton (bacillariophyceae, and chlorophyceae) during moderate and mostly microplankton during dry period. Zooplankton biomass was the lowest during peak discharge period and increased during moderate followed by dry period. The zooplankton abundance was controlled by dead organic matter during peak discharge period, while both phytoplankton biomass and dead organic matter during moderate discharge and mostly phytoplankton biomass during dry period. This study suggests that significant modification of physico-chemical properties by river discharge led to changes in phytoplankton composition and dead organic matter concentrations that alters biomass, abundance, and composition of zooplankton in the Godavari estuary.
20. Dynamics of the spatial structure of pulsed discharges in dense gases in point cathode−plane anode gaps and their erosion effect on the plane electrode surface
International Nuclear Information System (INIS)
Baksht, E. Kh.; Blinova, O. M.; Erofeev, M. V.; Karelin, V. I.; Ripenko, V. S.; Tarasenko, V. F.; Trenkin, A. A.; Shibitov, Yu. M.; Shulepov, M. A.
2016-01-01
The dynamics of the spatial structure of the plasma of pulsed discharges in air and nitrogen in a nonuniform electric field and their erosion effect on the plane anode surface were studied experimentally. It is established that, at a nanosecond front of the voltage pulse, a diffuse discharge forms in the point cathode–plane anode gap due to the ionization wave propagating from the cathode. As the gap length decreases, the diffuse discharge transforms into a spark. A bright spot on the anode appears during the diffuse discharge, while the spark channel forms in the later discharge stage. The microstructure of autographs of anode spots and spark channels in discharges with durations of several nanoseconds is revealed. The autographs consist of up to 100 and more microcraters 5–100 μm in diameter. It is shown that, due to the short duration of the voltage pulse, a diffuse discharge can be implemented, several pulses of which do not produce appreciable erosion on the plane anode or the soot coating deposited on it.
1. SUBMILLIMETER-WAVE ROTATIONAL SPECTROSCOPY OF H2F+
International Nuclear Information System (INIS)
Fujimori, R.; Kawaguchi, K.; Amano, T.
2011-01-01
Five pure rotational transitions of H 2 F + generated by a discharge in an HF/H 2 /Ar mixture were observed in the range 473-774 GHz with a backward-wave oscillator based submillimeter-wave spectrometer. A simultaneous analysis of the rotational lines with 120 combination differences for the ground state derived from the infrared spectra was carried out to determine the precise molecular constants for the ground state. The rotational transition frequencies that lie below 2 THz were calculated, together with their estimated uncertainties, to facilitate future astronomical identifications. The chemistry for H 2 F + formation in interstellar space is discussed in comparison with a case for recently detected H 2 Cl + .
2. The study on spatial distribution features of radiological plume discharged from Nuclear Power Plant based on C4ISRE
Science.gov (United States)
Ma, Yunfeng; Shen, Yue; Feng, Bairun; Yang, Fan; Li, Qiangqiang; Du, Boying; Bian, Yushan; Hu, Qiongqong; Wang, Qi; Hu, Xiaomin; Yin, Hang
2018-02-01
When the nuclear emergency accident occurs, it is very important to estimate three-dimensional space feature of the radioactive plume discharged from the source term for the emergency organization, as well as for better understanding of atmospheric dispersion processes. So, taking the Hongyanhe Nuclear Power Plant for example, the study for three-dimensional space feature of the radioactive plume is accomplished by applying atmospheric transport model (coupling of WRF-HYSPLIT) driven by FNL meteorological data of NCEP (04/01/2014-04/02/2014) based on the C4ISRE (Command, Control, Communications, Computer, Intelligence, Surveillance, Reconnaissance, Environmental Impact Assessment).The results show that the whole shape of three-dimensional plume was about irregular cloth influenced by wind; In the spatial domain (height > 16000m),the distribution of radiological plume, which looked more like horseshoe-shaped, presented irregular polygons of which the total length was 2258.7km, where covered the area of 39151km2; In the airspace from 4000m to 16000m, the plume, covered the area of 116269 km2, showed a triangle and the perimeter of that was 2280.4km; The shape of the plume was more like irregular quadrilateral, its perimeter was 2941.8km and coverage area of the plume was 131534km2;The overall distribution of the wind field showed a rectangular shape; Within the area along the horizontal direction 400m from origin to east and under height (lower than 2000m),the closer the distance coordinate (0,0), the denser the plume particles; Within the area of horizontal distance(500m-1000m) and height (4000m- 16000m), the particle density were relatively sparse and the spread extent of the plume particles from west to East was relatively large and the plume particles were mainly in the suspended state without obvious dry sedimentation; Within the area of horizontal distance (800m-1100m) and height (>16000m), there were relatively gentle horizontal diffusion of plume particles
3. H2O sources in regions of star formation
International Nuclear Information System (INIS)
Lo, K.Y.; Burke, B.F.; Haschick, A.D.
1975-01-01
Regions and objects believed to be in early stages of stellar formation have been searched for H 2 O 22-GHz line emission with the Haystack 120-foot (37 m) telescope. The objects include radio condensations, infrared objects in H ii regions, and Herbig-Haro objects. Nine new H 2 O sources were detected in the vicinity of such objects, including the Sharpless H ii regions S152, S235, S255, S269, G45.1+0.1, G45.5+0.1, AFCRL infrared object No. 809--2992, and Herbig-Haro objects 1 and 9. The new H 2 O sources detected in H ii regions are associated, but not coincident, with the the radio condensations. Water vapor line emission was detected in approx.25 percent of the regions searched. The association of H 2 O sources with regions of star formation is taken to be real. The spatial relationship of H 2 O sources to infrared objects, radio condensations, class I OH sources, and molecular clouds are discussed. The suggestion is made that an H 2 O source may be excited by a highly obscured star of extreme youth
4. A New Overpotential — Capacitance Mechanism for H2 Electrode
Directory of Open Access Journals (Sweden)
Glenn Wei
2006-10-01
Full Text Available The H2 electrode is commonly assumed to be a half-cell, 2 H+ 2e == H2, andexplained by the Nernst equation. We cannot assume that the H+ is easily reduced to H2 inan H2 saturated solution, and H2 becoming oxidized to H+ in a strongly acid solution againstthe equilibrium principle. How can the H2 gas is involved from a basic solution where thereis practically no H+ ions? Another equilibrium has been postulated, H2 (soln = 2H(adsorbed on metal = 2 H 2e. This paper reports the results of studying the H2 electrodeusing various techniques, such as adsorption, bubbling with H2, and N2, charging,discharging, and recharging, replacing the salt bridge with a conducting wire, etc. Aninteresting overpotential was observed that bubbling H2 into the solution caused a suddenchange of potential to more negative without changing the solution pH. The H2 may bereplaced by N2 to give a similar calibration curve without the overpotential. The resultscontradict the redox mechanism. When the Pt is separated by H2 coating, it cannot act as acatalyst in the solution. Our results seem to explain the H2 electrode mechanism as thecombination of its overpotential and capacitance potential. Bubbling of H2 or N2 onlyremoves interfering gases such as O2 and CO2. Since neither H2 nor N2 is involved in thepotential development, it is improper to call the H2 or N2 electrode. A term of pH / OH Ptelectrode, like the pH / OH glass electrode, is suggested.
5. Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2
Science.gov (United States)
Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.
2013-01-01
We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.
6. H2O2: A Dynamic Neuromodulator
Science.gov (United States)
Rice, Margaret E.
2012-01-01
Increasing evidence implicates hydrogen peroxide (H2O2) as an intra- and intercellular signaling molecule that can influence processes from embryonic development to cell death. Most research has focused on relatively slow signaling, on the order of minutes to days, via second messenger cascades. However, H2O2 can also mediate subsecond signaling via ion channel activation. This rapid signaling has been examined most thoroughly in the nigrostriatal dopamine (DA) pathway, which plays a key role in facilitating movement mediated by the basal ganglia. In DA neurons of the substantia nigra, endogenously generated H2O2 activates ATP-sensitive K+ (KATP) channels that inhibit DA neuron firing. In the striatum, H2O2 generated downstream from glutamatergic AMPA receptor activation in medium spiny neurons acts as a diffusible messenger that inhibits axonal DA release, also via KATP channels. The source of dynamically generated H2O2 is mitochondrial respiration; thus, H2O2 provides a novel link between activity and metabolism via KATP channels. Additional targets of H2O2 include transient receptor potential (TRP) channels. In contrast to the inhibitory effect of H2O2 acting via KATP channels, TRP channel activation is excitatory. This review describes emerging roles of H2O2 as a signaling agent in the nigrostriatal pathway and other basal ganglia neurons. PMID:21666063
7. Dissociative recombination of molecular ions H2+
International Nuclear Information System (INIS)
Abarenov, A.V.; Marchenko, V.S.
1989-01-01
The total cross sections of dissociation and dissociative recombination of slow electrons and molecular ions H 2 + have been calculated in terms of the quasiclassical and dipole approximations. In the calculations allowance was made for the quantum nature of vibrational motion of heavy particles and presence of autoionization of divergence states of the H 2 (Σ u , nl) molecules. It is shown that the H 2 + ion dissociation cross sections are dominant in increase of the electron energy in the ε >or approx. 2-3 eV region for H 2 + (v) ion distribution over the vibrational levels characteristic for the beam experiments. 15 refs.; 5 figs
8. Evaluating Spatial Variability in Sediment and Phosphorus Concentration-Discharge Relationships Using Bayesian Inference and Self-Organizing Maps
Science.gov (United States)
Underwood, Kristen L.; Rizzo, Donna M.; Schroth, Andrew W.; Dewoolkar, Mandar M.
2017-12-01
Given the variable biogeochemical, physical, and hydrological processes driving fluvial sediment and nutrient export, the water science and management communities need data-driven methods to identify regions prone to production and transport under variable hydrometeorological conditions. We use Bayesian analysis to segment concentration-discharge linear regression models for total suspended solids (TSS) and particulate and dissolved phosphorus (PP, DP) using 22 years of monitoring data from 18 Lake Champlain watersheds. Bayesian inference was leveraged to estimate segmented regression model parameters and identify threshold position. The identified threshold positions demonstrated a considerable range below and above the median discharge—which has been used previously as the default breakpoint in segmented regression models to discern differences between pre and post-threshold export regimes. We then applied a Self-Organizing Map (SOM), which partitioned the watersheds into clusters of TSS, PP, and DP export regimes using watershed characteristics, as well as Bayesian regression intercepts and slopes. A SOM defined two clusters of high-flux basins, one where PP flux was predominantly episodic and hydrologically driven; and another in which the sediment and nutrient sourcing and mobilization were more bimodal, resulting from both hydrologic processes at post-threshold discharges and reactive processes (e.g., nutrient cycling or lateral/vertical exchanges of fine sediment) at prethreshold discharges. A separate DP SOM defined two high-flux clusters exhibiting a bimodal concentration-discharge response, but driven by differing land use. Our novel framework shows promise as a tool with broad management application that provides insights into landscape drivers of riverine solute and sediment export.
9. H2-H2O-HI Hydrogen Separation in H2-H2O-HI Gaseous Mixture Using the Silica Membrane
International Nuclear Information System (INIS)
Pandiangan, Tumpal
2002-01-01
It was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical lS process. Porous alumina tube having pore size of 0.1 μm was modified by chemical vapor deposition using tetraethoxysilane. The permeance single gas of He, H 2 , and N 2 was measured at 300-600 o C. Hydrogen permeance of the modified membrane at a permeation temperature of 600 o C was about 5.22 x 10 -08 mol/Pa m 2 s, and 3.2 x 10 -09 of using gas mixture of H 2 -H 2 O-HI, where as HI permeances was below 1 x 10 -10 mol/Pa m 2 s. The Hydrogen permeance relative was not changed after 25 hours exposure in a mixture of H 2 -H 2 O-HI gas at the temperature of 450 o C. (author)
10. Spatially and Temporally Resolved Atomic Oxygen Measurements in Short Pulse Discharges by Two Photon Laser Induced Fluorescence
Science.gov (United States)
Lempert, Walter; Uddi, Mruthunjaya; Mintusov, Eugene; Jiang, Naibo; Adamovich, Igor
2007-10-01
Two Photon Laser Induced Fluorescence (TALIF) is used to measure time-dependent absolute oxygen atom concentrations in O2/He, O2/N2, and CH4/air plasmas produced with a 20 nanosecond duration, 20 kV pulsed discharge at 10 Hz repetition rate. Xenon calibrated spectra show that a single discharge pulse creates initial oxygen dissociation fraction of ˜0.0005 for air like mixtures at 40-60 torr total pressure. Peak O atom concentration is a factor of approximately two lower in fuel lean (φ=0.5) methane/air mixtures. In helium buffer, the initially formed atomic oxygen decays monotonically, with decay time consistent with formation of ozone. In all nitrogen containing mixtures, atomic oxygen concentrations are found to initially increase, for time scales on the order of 10-100 microseconds, due presumably to additional O2 dissociation caused by collisions with electronically excited nitrogen. Further evidence of the role of metastable N2 is demonstrated from time-dependent N2 2^nd Positive and NO Gamma band emission spectroscopy. Comparisons with modeling predictions show qualitative, but not quantitative, agreement with the experimental data.
11. Histone H2AX in DNA repair
International Nuclear Information System (INIS)
Lewandowska, H.; Szumiel, I.
2002-01-01
The paper reviews the recent reports on the role of the phosphorylated histone H2AX (γ-H2AX). The modification of this histone is an important part of the cellular response to the induction of DNA double strand brakes (DSB) by ionising radiation and other DSB-generating factors. In irradiated cells the modification is carried out mainly by ATM (ataxia-telangiectasia mutated) kinase, the enzyme that starts the alarm signalling upon induction of DSB.γ-H2AX molecules are formed within 1-3 min after irradiation and form foci at the sites of DSB. This seems to be necessary for the recruitment of repair factors that are later present in foci of damaged nuclei. Modification of a constant percentage of H2AX molecules per DSB takes place, corresponding to chromatin domains of megabase of DNA. (author)
12. H2O2 INDUCES DELAYED HYPEREXCITABILITY IN NUCLEUS TRACTUS SOLITARII NEURONS
Science.gov (United States)
Ostrowski, Tim D.; Hasser, Eileen M.; Heesch, Cheryl M.; Kline, David D.
2014-01-01
Hydrogen peroxide (H2O2) is a stable reactive oxygen species and potent neuromodulator of cellular and synaptic activity. Centrally, endogenous H2O2 is elevated during bouts of hypoxia-reoxygenation, a variety of disease states, and aging. The nucleus tractus solitarii (nTS) is the central termination site of visceral afferents for homeostatic reflexes and contributes to reflex alterations during these conditions. We determined the extent to which H2O2 modulates synaptic and membrane properties in nTS neurons in rat brainstem slices. Stimulation of the tractus solitarii (which contains the sensory afferent fibers) evoked synaptic currents that were not altered by 10 – 500 μM H2O2. However, 500 μM H2O2 modulated several intrinsic membrane properties of nTS neurons, including a decrease in input resistance, hyperpolarization of resting membrane potential (RMP) and action potential (AP) threshold (THR), and an initial reduction in AP discharge to depolarizing current. H2O2 increased conductance of barium-sensitive potassium currents, and block of these currents ablated H2O2-induced changes in RMP, input resistance and AP discharge. Following washout of H2O2 AP discharge was enhanced due to depolarization of RMP and a partially maintained hyperpolarization of THR. Hyperexcitability persisted with repeated H2O2 exposure. H2O2 effects on RMP and THR were ablated by intracellular administration of the antioxidant catalase, which was immunohistochemically identified in neurons throughout the nTS. Thus, H2O2 initially reduces excitability of nTS neurons that is followed by sustained hyperexcitability, which may play a profound role in cardiorespiratory reflexes. PMID:24397952
13. Temporal and spatial evolution of EHD particle flow onset in air in a needle-to-plate negative DC corona discharge
International Nuclear Information System (INIS)
Mizeraczyk, J; Berendt, A; Podlinski, J
2016-01-01
In this paper we present images showing the temporal and spatial evolution of the electrohydrodynamic (EHD) flow of dust particles (cigarette smoke) suspended in still air in a needle-to-plate negative DC corona discharge arrangement just after the corona onset, i.e. in the first stage of development of the EHD particle flow. The experimental apparatus for our study of the EHD flow onset consisted of a needle-to-plate electrode arrangement, high voltage power supply and time-resolved EHD imaging system based on 2D time-resolved particle image velocimetry equipment. The time-resolved flow images clearly show the formation of a ball-like flow structure at the needle tip just after the corona discharge onset, and its evolution into a mushroom-like object moving to the collecting electrode. After a certain time, when the mushroom-like object is still present in the interelectrode gap a second mushroom-like object forms near the needle electrode and starts to move towards the collecting electrode. Before the first mushroom-like object reaches the collecting electrode several similar mushroom-like objects can be formed and presented simultaneously in the interelectrode gap. They look like a series of mushroom-like minijets shot from the needle electrode vicinity towards the collecting electrode. The simultaneous presence of mushroom-like minijets in the interelectrode gap in the corona discharge in particle-seeded air resembles the negative-ion-charged ‘clouds’ (induced by the Trichel pulses) traversing simultaneously the interelectrode gap of the corona discharge in air, predicted a long time ago by Loeb, and Lama and Gallo and recently by Dordizadeh et al . Analysing the time behaviours of the mushroom-like minijets and current waveform in the corona discharge in particle-seeded air, we found that the Trichel pulse trains, formed just after the corona onset initiates the mushroom-like minijets. The first stage of development of the EHD particle flow, the area of
14. H2SO4-HNO3-H2O ternary system in the stratosphere
Science.gov (United States)
Kiang, C. S.; Hamill, P.
1974-01-01
Estimation of the equilibrium vapor pressure over the ternary system H2SO4-HNO3-H2O to study the possibility of stratospheric aerosol formation involving HNO3. It is shown that the vapor pressures for the ternary system H2SO4-HNO3-H2O with weight composition around 70-80% H2SO4, 10-20% HNO3, 10-20% H2O at -50 C are below the order of 10 to the minus 8th mm Hg. It is concluded that there exists more than sufficient nitric acid and water vapor in the stratosphere to participate in ternary system aerosol formation at -50 C. Therefore, HNO3 should be present in stratospheric aerosols, provided that H2SO4 is also present.
15. Characterization of the Spatial and Temporal Variations of Submarine Groundwater Discharge Using Electrical Resistivity and Seepage Measurements
Science.gov (United States)
Durand, Josephine Miryam Kalyanie
Submarine groundwater discharge (SGD) encompasses all fluids crossing the sediment/ocean interface, regardless of their origin, composition or driving forces. SGD provides a pathway for terrestrial contaminants that can significantly impact coastal ecosystems. Overexploitation of groundwater resources can decrease SGD which favors seawater intrusion at depth. Understanding SGD is therefore crucial for water quality and resource management. Quantifying SGD is challenging due to its diffuse and heterogeneous nature, in addition to significant spatio-temporal variations at multiple scales. In this thesis, an integrated approach combining electrical resistivity (ER) surveys, conductivity and temperature point measurements, seepage rates using manual and ultrasonic seepage meters, and pore fluid salinities was used to characterize SGD spatio-temporal variations and their implications for contaminant transport at several locations on Long Island, NY. The influence of surficial sediments on SGD distribution was investigated in Stony Brook Harbor. A low-permeability mud layer, actively depositing in the harbor, limits SGD at the shoreline, prevents mixing with seawater and channels a significant volume of freshwater offshore. SGD measured at locations without mud is high and indicates significant mixing between porewater and seawater. A 2D steady-state density-difference numerical model of the harbor was developed using SEAWAT and was validated by our field observations. Temporal variations of SGD due to semi-diurnal tidal forcing were studied in West Neck Bay, Shelter Island, using a 12-hr time-lapse ER survey together with continuous salinity and seepage measurements in the intertidal zone. The observed dynamic patterns of groundwater flux and salinity distribution disagree with published standard transient state numerical models, suggesting the need for developing more specific models of non-homogeneous anisotropic aquifers. SGD distribution and composition were
16. Autoionizing np Rydberg states of H2
International Nuclear Information System (INIS)
Xu, E.Y.; Helm, H.; Kachru, R.
1989-01-01
We report a study of the autoionizing np Rydberg states near the lowest ionization threshold of H 2 . Using resonant two-photon excitation, intermediate states in specific rotovibrational levels in the double well, E,F 1 Σ/sub g/ + states are prepared. Then, a second, tunable laser is used to photoionize via excitation of the np Rydberg states. Because of the stepwise laser excitation scheme employed in our experiment the photoionization occurs from states with vibrational wave functions very similar to those of the H 2 + core. As a consequence, the autoionizing states appear as nearly symmetric resonances, rather than the highly asymmetric Beutler-Fano profiles observed from the direct photoexcitation from the ground state of H 2 . Our experiments show that the J = 1 np states are broader than the J = 3 np states converging to the same limit, suggesting that the two states autoionize into the epsilon-cp and epsilon-cf continuum, respectively. We compare our observations with a theoretical analysis using a multichannel quantum defect theory. The J = 1 states reveal the profound effect caused by the perturbation of the autoionizing Rydberg series converging to the lowest vibrational and rotational state of H 2 + by low-n states converging to higher vibrational states of the H 2 -ion core
17. H2@Scale Resource and Market Analysis
Energy Technology Data Exchange (ETDEWEB)
Ruth, Mark
2017-05-04
The 'H2@Scale' concept is based on the potential for wide-scale utilization of hydrogen as an energy intermediate where the hydrogen is produced from low cost energy resources and it is used in both the transportation and industrial sectors. H2@Scale has the potential to address grid resiliency, energy security, and cross-sectoral emissions reductions. This presentation summarizes the status of an ongoing analysis effort to quantify the benefits of H2@Scale. It includes initial results regarding market potential, resource potential, and impacts of when electrolytic hydrogen is produced with renewable electricity to meet the potential market demands. It also proposes additional analysis efforts to better quantify each of the factors.
18. H-2 restriction: Independent recognition of H-2 and foreign antigen by a single receptor
Science.gov (United States)
Siliciano, Robert F.; Zacharchuk, Charles M.; Shin, Hyun S.
1980-01-01
We describe two situations in which the recognition of hapten can compensate for the lack of recognition of appropriate H-2 gene products in hapten-specific, H-2 restricted, T lymphocyte-mediated cytolysis. First, we show that although recognition of appropriate H-2 gene products is essential for the lysis of target cells bearing a low hapten density, significant hapten-specific lysis of H-2 inappropriate target cells is observed at high levels of target cell derivatization. Secondly, we show that hapten-conjugated anti-H-2 antibody inhibits cytolysis poorly even though its binding to target cell H-2 antigens is equivalent to that of underivatized antibody. These results suggest that hapten and H-2 are recognized independently and are therefore inconsistent with the altered-self model. Although our data do not exclude the dual-recognition model, we prefer to interpret them within the framework of a single-receptor model in which hapten and H-2 are recognized independently by receptors of identical idiotype on the T cell. We postulate that the affinity of these receptors for the relevant H-2 gene product is low enough so that the T cell is not activated by encounters with normal-self cells expressing that H-2 gene product. However, when self cells express in addition a foreign antigen that can also be recognized by the same receptor, then the force of T cell-target cell interaction may be increased sufficiently to activate T cell effector function. PMID:6966404
19. Spatial and temporal variations of winter discharge under climate change: Case study of rivers in European Russia
Directory of Open Access Journals (Sweden)
E. A. Telegina
2015-05-01
Full Text Available An important problem in hydrology is the re-evaluation of the current resources of surface and underground waters in the context of ongoing climate changes. The main feature of the present-day changes in water regime in the major portion of European Russia (ER is the substantial increase in low-water runoff, especially in winter. In this context, some features of the spatial–temporal variations of runoff values during the winter low-water period are considered. Calculations showed that the winter runoff increased at more than 95% of hydrological gauges. Changes in the minimum and average values of runoff during winter low-water period and other characteristics are evaluated against the background of climate changes in the recent decades. The spatial and temporal variability of winter runoff in European Russia is evaluated for the first time.
20. H2 molecules and the intercloud medium
International Nuclear Information System (INIS)
Hill, J.K.; Hollenbach, D.J.
1976-01-01
We discuss expected column of densities of H 2 in the intercloud medium and the possible use of molecules as indicators of intercloud physical conditions. We treat molecule formation by the H - process and on graphite grains and show that the Barlow-Silk hypothesis of a 1 eV semichemical hydrogen-graphite bond leads to a large enhancement of the intercloud molecule formation rate. Rotational excitation calculations are presented for both cloud and intercloud conditions which show, in agreement with Jura, that the presently observed optically thin H 2 absorption components are more likely to originate in cold clouds than in the intercloud medium
1. Planetary Nebulae with H2 Emission
OpenAIRE
Margarita Rosado; Lorena Arias
2003-01-01
Hacemos una revisión de la emisión en hidrogeno molecular (H2) de las nebulosas planetarias (NPs). Vemos como esta emisión se encuentra asociada a objetos de forma bipolar. Describimos los niveles de energía de la molécula de hidrogeno, los principales mecanismos para poblarlos (choques y fluorescencia) y las formas en que se puede discriminar que mecanismo opera. Proponemos que la cinemática del H2 también puede ser usada para discriminar el mecanismo de excitación de sus líneas de emisión. ...
2. Yield of H2O2 in Gas-Liquid Phase with Pulsed DBD
Science.gov (United States)
Jiang, Song; Wen, Yiyong; Liu, Kefu
2014-01-01
Electric discharge in water can generate a large number of oxidants such as ozone, hydrogen peroxide and hydroxyl radicals. In this paper, a non-thermal plasma processing system was established by means of pulsed dielectric barrier discharge in gas-liquid phase. The electrodes of discharge reactor were staggered. The yield of H2O2 was enhanced after discharge. The effects of discharge time, discharge voltage, frequency, initial pH value, and feed gas were investigated. The concentration of hydrogen peroxide and ozone was measured after discharge. The experimental results were fully analyzed. The chemical reaction equations in water were given as much as possible. At last, the water containing Rhodamine B was tested in this system. The degradation rate came to 94.22% in 30 min.
3. VUV photoionization cross sections of HO2, H2O2, and H2CO.
Science.gov (United States)
Dodson, Leah G; Shen, Linhan; Savee, John D; Eddingsaas, Nathan C; Welz, Oliver; Taatjes, Craig A; Osborn, David L; Sander, Stanley P; Okumura, Mitchio
2015-02-26
The absolute vacuum ultraviolet (VUV) photoionization spectra of the hydroperoxyl radical (HO2), hydrogen peroxide (H2O2), and formaldehyde (H2CO) have been measured from their first ionization thresholds to 12.008 eV. HO2, H2O2, and H2CO were generated from the oxidation of methanol initiated by pulsed-laser-photolysis of Cl2 in a low-pressure slow flow reactor. Reactants, intermediates, and products were detected by time-resolved multiplexed synchrotron photoionization mass spectrometry. Absolute concentrations were obtained from the time-dependent photoion signals by modeling the kinetics of the methanol oxidation chemistry. Photoionization cross sections were determined at several photon energies relative to the cross section of methanol, which was in turn determined relative to that of propene. These measurements were used to place relative photoionization spectra of HO2, H2O2, and H2CO on an absolute scale, resulting in absolute photoionization spectra.
4. Remote control of the dissociative ionization of H2 based on electron-H2 + entanglement
Science.gov (United States)
Wang, Jun-Ping; He, Feng
2018-04-01
The single ionization of H2 in strong laser fields creates the correlated electron-H2 + pair. Based on such a correlation, we conceive a strategy to control the energy spectra of the freed electron or dissociative fragments by simulating the time-dependent Schrödinger equation. Two attosecond pulses in a train produce the replica of electron-H2 + pairs, which are to be steered by a time-delayed phase-stabilized (mid)infrared laser pulse. By controlling the behavior of the freed electron, the dissociation of H2 + can be controlled even though there is no direct laser-H2 + coupling. On the other hand, the photoelectron energy spectra can be manipulated via laser-H2 + coupling. This study demonstrates the entanglement of molecular quantum wave packets, and affords a route to remotely control molecular dissociative ionization.
5. Effect of the spatial distribution of physical aquifer properties on modelled water table depth and stream discharge in a headwater catchment
Directory of Open Access Journals (Sweden)
C. Gascuel-Odoux
2010-07-01
Full Text Available Water table depth and its dynamics on hillslopes are often poorly predicted despite they control both water transit time within the catchment and solute fluxes at the catchment outlet. This paper analyses how relaxing the assumption of lateral homogeneity of physical properties can improve simulations of water table depth and dynamics. Four different spatial models relating hydraulic conductivity to topography have been tested: a simple linear relationship, a linear relationship with two different topographic indexes, two Ks domains with a transitional area. The Hill-Vi model has been modified to test these hypotheses. The studied catchment (Kervidy-Naizin, Western France is underlain by schist crystalline bedrock. A shallow and perennial groundwater highly reactive to rainfall events mainly develops in the weathered saprolite layer. The results indicate that (1 discharge and the water table in the riparian zone are similarly predicted by the four models, (2 distinguishing two Ks domains constitutes the best model and slightly improves prediction of the water table upslope, and (3 including spatial variations in the other parameters such as porosity or rate of hydraulic conductivity decrease with depth does not improve the results. These results underline the necessity of better investigations of upslope areas in hillslope hydrology.
6. Catalytical conversion from ortho-H2 to para-H2
International Nuclear Information System (INIS)
Corat, E.J.
1984-01-01
The classical theory of ortho to para-H 2 conversion is discussed, considering the catalytical action of an inhomogeneous magnetic field on a surface with magnetic particles. In particular, the use of charcoal as a catalyst at low temperatures (77 0 K) is considered and some results are presented. The development of a sensor for the determination of para-H 2 concentration in H 2 gas is studied. Experimental results with this sensor are also shown. (Author) [pt
7. Study of the solubility, viscosity and density in Na+, Zn2+/Cl− − H2O, Na+ − Zn2+ − (H2PO2)− − H2O, Na+, Cl−/(H2PO2)− − H2O, and Zn2+, Cl−/(H2PO2)− − H2O ternary systems, and in Na+, Zn2+/Cl−, (H2PO2)−//H2O reciprocal quaternary system at 273.15 K
International Nuclear Information System (INIS)
Adiguzel, Vedat; Erge, Hasan; Alisoglu, Vahit; Necefoglu, Hacali
2014-01-01
Highlights: • The physicochemical properties of ternary and one quaternary have been studied. • Reciprocal quaternary systems’ solubility and phase equilibrium have been studied. • In all systems the solid phases have been found. • It was found that Zn(H 2 PO 2 ) 2 salt contains 70% of the general crystallization field. - Abstract: The solubility and the physicochemical properties (density, viscosity) in the Na-Zn- Cl-H 2 O), (Na + Zn + H 2 PO 2 + H 2 O), (Na + Cl + H 2 PO 2 + H 2 O), and (Zn + Cl + H 2 PO 2 + H 2 O) ternaries, and in Na + , Zn 2+ /Cl − , (H 2 PO 2 ) − //H 2 O reciprocal quaternary systems at T = 273.15 K were investigated by using the isothermal method. The diagrams of ternary salts systems, (NaCl + ZnCl 2 + H 2 O), (NaCl + NaH 2 PO 2 + H 2 O), (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), are plotted in figures 1–4. However, whole ions of reciprocal quaternary salt systems are plotted in figure 5. Additionally, the density and viscosity values of ternary systems vs. their corresponding composition values in weight per cent are plotted in figures 6–10. At the (i) (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ii) (NaCl + ZnCl 2 + H 2 O), (iii) (NaCl + NaH 2 PO 2 + H 2 O), (iv) (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O) ternary systems the solid phase compositions have been determined as: (i) Zn(H 2 PO 2 ) 2 ⋅ H 2 O, Zn(H 2 PO 2 ) 2 , ZnCl 2 ⋅ 2H 2 O, (ii) NaCl, 2NaCl ⋅ ZnCl 2 ⋅ 2H 2 O, and ZnCl 2 ⋅ 2H 2 O, (iii) NaCl and NaH 2 PO 2 ⋅ H 2 O, (iv) Zn(H 2 PO 2 ) 2 ⋅ H 2 O and NaH 2 PO 2 ⋅ H 2 O, respectively. On the other hand reciprocal quaternary system was observed as: ZnCl 2 ⋅ 2H 2 O, 2NaCl ⋅ ZnCl 2 ⋅ 2H 2 O, Zn(H 2 PO 2 ) 2 ⋅ H 2 O, NaH 2 PO 2 ⋅ H 2 O, NaCl. According to results, the least soluble salt was Zn(H 2 PO 2 ) 2 . The crystallization field of this salt, being the largest in comparison with those of other salts, occupied 70% of the general crystallization field
8. Fluorescent excitation of interstellar H2
NARCIS (Netherlands)
Black, J.H.; Dishoeck, van E.F.
1987-01-01
The infrared emission spectrum of H2 excited by ultraviolet absorption, followed by fluorescence, was investigated using comprehensive models of interstellar clouds for computing the spectrum and to assess the effects on the intensity to various cloud properties, such as density, size, temperature,
9. The molecular hydrogen explorer H2EX
NARCIS (Netherlands)
Boulanger, F.; Maillard, J. P.; Appleton, P.; Falgarone, E.; Lagache, G.; Schulz, B.; Wakker, B. P.; Bressan, A.; Cernicharo, J.; Charmandaris, V.; Drissen, L.; Helou, G.; Henning, T.; Lim, T. L.; Valentjin, E. A.; Abergel, A.; Bourlot, J. Le; Bouzit, M.; Cabrit, S.; Combes, F.; Deharveng, J. M.; Desmet, P.; Dole, H.; Dumesnil, C.; Dutrey, A.; Fourmond, J. J.; Gavila, E.; Grangé, R.; Gry, C.; Guillard, P.; Guilloteau, S.; Habart, E.; Huet, B.; Joblin, C.; Langer, M.; Longval, Y.; Madden, S. C.; Martin, C.; Miville-Deschênes, M. A.; Pineau Des Forêts, G.; Pointecouteau, E.; Roussel, H.; Tresse, L.; Verstraete, L.; Viallefond, F.; Bertoldi, F.; Jorgensen, J.; Bouwman, J.; Carmona, A.; Krause, O.; Baruffolo, A.; Bonoli, C.; Bortoletto, F.; Danese, L.; Granato, G. L.; Pernechele, C.; Rampazzo, R.; Silva, L.; Zotti, G. De; Pardo, J.; Spaans, M.; van der Tak, F. F. S.; Wild, W.; Ferlet, M. J.; Ramsay Howat, S. K.; Smith, M. D.; Swinyard, B.; Wright, G. S.; Joncas, G.; Martin, P. G.; Davis, C. J.; Draine, B. T.; Goldsmith, P. F.; Mainzer, A. K.; Ogle, P.; Rinehart, S. A.; Stacey, G. J.; Tielens, A. G. G. M.
The Molecular Hydrogen Explorer, H2 EX, was proposed in response to the ESA 2015 - 2025 Cosmic Vision Call as a medium class space mission with NASA and CSA participations. The mission, conceived to understand the formation of galaxies, stars and planets from molecular hydrogen, is designed to
10. EPA H2O User Manual
Science.gov (United States)
EPA H2O is a software tool designed to support research being conducted in the Tampa Bay watershed to provide information, data, and approaches and guidance that communities can use to examine alternatives when making strategic decisions to support a prosperous and environmentall...
11. Isotopic equilibrium constants of the deuterium exchange between HDO and H2S, H2Se and H2Te
International Nuclear Information System (INIS)
Marx, D.
1959-11-01
We have determined experimentally the equilibrium constant K of each of the following isotope exchanges: SH 2 + OHD ↔ SHD + OH 2 ; SeH 2 + OHD ↔ SeHD + OH 2 ; TeH 2 + OHD ↔ TeHD + OH 2 . In gaseous phase, statistical thermodynamics leads to the expression: K (Z OHD x Z RH 2 )/(Z OH 2 x Z RHD ) x e W/T (R being the elements S, Se or Te). Z, the partition functions, have been calculated and, through our experimental results, the constant W has been determined. Having obtained W, the equilibrium constant K has been calculated for a series of temperatures. (author) [fr
12. Pancreatitis - discharge
Science.gov (United States)
Chronic pancreatitis - discharge; Pancreatitis - chronic - discharge; Pancreatic insufficiency - discharge; Acute pancreatitis - discharge ... You were in the hospital because you have pancreatitis. This is a swelling of the pancreas. You ...
13. Reactions of electronically excited molecular nitrogen with H2 and H2O molecules: theoretical study
Science.gov (United States)
Pelevkin, Alexey V.; Sharipov, Alexander S.
2018-05-01
Comprehensive quantum chemical analysis with the usage of the second-order perturbation multireference XMCQDPT2 approach was carried out to study the processes in the + H2 and + H2O systems. The energetically favorable reaction pathways have been revealed based on the exploration of potential energy surfaces. It has been shown that the reactions + H2 and + H2O occur with small activation barriers and, primarily, lead to the formation of N2H + H and N2H + OH products, respectively. Further, the interaction of these species could give rise to the ground state and H2 (or H2O) products, however, the estimations, based on RRKM theory and dynamic reaction coordinate calculations, exhibited that the + H2 and + H2O reactions lead to the dissociative quenching predominately. Appropriate rate constants for revealed reaction channels have been estimated by using a canonical variational theory and capture approximation. Corresponding three-parameter Arrhenius expressions for the temperature range T = 300 ‑ 3000 K were reported.
14. High purity H2/H2O/Ni/SZ electrodes at 500º C
DEFF Research Database (Denmark)
Høgh, Jens Valdemar Thorvald; Hansen, Karin Vels; Norrman, Kion
2013-01-01
of stabilized zirconia (SZ) with 10, 13 and 18 mol% yttria and one with 6 mol% scandia plus 4 mol% yttria were studied at open circuit voltage at 400-500 C in mixtures of H2/H2O over 46 days. The polarization resistances (Rp) for all samples increased significantly during the first 10-20 days at 500 C...
15. Heart pacemaker - discharge
Science.gov (United States)
Cardiac pacemaker implantation - discharge; Artificial pacemaker - discharge; Permanent pacemaker - discharge; Internal pacemaker - discharge; Cardiac resynchronization therapy - discharge; CRT - discharge; ...
16. Investigations on H2 combustion processes
International Nuclear Information System (INIS)
Breitung, W.; Hesselschwerdt, E.; Massier, H.; Moeschke, M.; Redlinger, R.; Wilkening, H.; Werle, H.; Wolff, J.
1995-01-01
During 1994 results were obtained for turbulent deflagrations, detonation ignition criteria, and detonations. In the field of turbulent deflagrations, two different 2-d codes have been developed, which are capable of describing the large spectrum of combustion regimes important for severe accident analysis. Two series of large scale experiments on turbulent H 2 -air combustion have been completed, one with premixed atmospheres, one with dynamic H 2 -injection into the test volume. They provided new clean data for code evaluation on reactor relevant scale (up to 480 m 3 volume). In the field of detonation ignition criteria different mechanisms were investigated which can trigger a transition from deflagration to detonation (DDT). Large scale experiments were performed on turbulent jet ignition of unconfined H 2 -air mixtures. As in earlier small scale tests, detonation ignition was only observed above 25% hydrogen in air. Such reactive mixtures will be rare in severe accidents. Pressure wave focussing was also investigated experimentally. The Mach numbers necessary to trigger a local detonation in different geometries and in different H 2 -air mixtures were measured on small scale. The conditions necessary for a shockless detonation ignition by induction time gradients were calculated. Only close to the reactor pressure vessel the corresponding temperatures and temperature gradients can possibly exist, not in the remainder of the containment. In the field of detonation modeling the code development was completed. Detonation experiments were performed in a 12 m tube equipped with complex obstacles. Some of the data were used to validate the codes. The remaining analysis will be performed in early 1995. The codes can describe well all important physical phenomena which influence detonation loads in complex 3-d geometries. The validated codes were used to calculate local detonation loads in a preliminary EPR containment. (orig./HP)
17. Electron mass stopping power in H2
Science.gov (United States)
Fursa, Dmitry V.; Zammit, Mark C.; Threlfall, Robert L.; Savage, Jeremy S.; Bray, Igor
2017-08-01
Calculations of electron mass stopping power (SP) of electrons in H2 have been performed using the convergent close-coupling method for incident electron energies up to 2000 eV. Convergence of the calculated SP has been established by increasing the size of the close-coupling expansion from 9 to 491 states. Good agreement was found with the SP measurements of Munoz et al. [Chem. Phys. Lett. 433, 253 (2007), 10.1016/j.cplett.2006.10.114].
18. Solid H2 in the interstellar medium
Science.gov (United States)
Füglistaler, A.; Pfenniger, D.
2018-06-01
Context. Condensation of H2 in the interstellar medium (ISM) has long been seen as a possibility, either by deposition on dust grains or thanks to a phase transition combined with self-gravity. H2 condensation might explain the observed low efficiency of star formation and might help to hide baryons in spiral galaxies. Aims: Our aim is to quantify the solid fraction of H2 in the ISM due to a phase transition including self-gravity for different densities and temperatures in order to use the results in more complex simulations of the ISM as subgrid physics. Methods: We used molecular dynamics simulations of fluids at different temperatures and densities to study the formation of solids. Once the simulations reached a steady state, we calculated the solid mass fraction, energy increase, and timescales. By determining the power laws measured over several orders of magnitude, we extrapolated to lower densities the higher density fluids that can be simulated with current computers. Results: The solid fraction and energy increase of fluids in a phase transition are above 0.1 and do not follow a power law. Fluids out of a phase transition are still forming a small amount of solids due to chance encounters of molecules. The solid mass fraction and energy increase of these fluids are linearly dependent on density and can easily be extrapolated. The timescale is below one second, the condensation can be considered instantaneous. Conclusions: The presence of solid H2 grains has important dynamic implications on the ISM as they may be the building blocks for larger solid bodies when gravity is included. We provide the solid mass fraction, energy increase, and timescales for high density fluids and extrapolation laws for lower densities.
19. Crystalline and amorphous H2O on Charon
Science.gov (United States)
Dalle Ore, Cristina M.; Cruikshank, Dale P.; Grundy, Will M.; Ennico, Kimberly; Olkin, Catherine B.; Stern, S. Alan; Young, Leslie A.; Weaver, Harold A.
2015-11-01
Charon, the largest satellite of Pluto, is a gray-colored icy world covered mostly in H2O ice, with spectral evidence for NH3, as previously reported (Cook et al. 2007, Astrophys. J. 663, 1406-1419 Merlin, et al. 2010, Icarus, 210, 930; Cook, et al. 2014, AAS/Division for Planetary Sciences Meeting Abstracts, 46, #401.04). Images from the New Horizons spacecraft reveal a surface with terrains of widely different ages and a moderate degree of localized coloration. The presence of H2O ice in its crystalline form (Brown & Calvin 2000 Science 287, 107-109; Buie & Grundy 2000 Icarus 148, 324-339; Merlin et al, 2010) along with NH3 is consistent with a fresh surface.The phase of H2O ice is a key tracer of variations in temperature and physical conditions on the surface of outer Solar System objects. At Charon’s surface temperature H2O is expected to be amorphous, but ground-based observations (e.g., Merlin et al. 2010) show a clearly crystalline signature. From laboratory experiments it is known that amorphous H2O ice becomes crystalline at temperatures of ~130 K. Other mechanisms that can change the phase of the ice from amorphous to crystalline include micro-meteoritic bombardment (Porter et al. 2010, Icarus, 208, 492) or resurfacing processes such as cryovolcanism.New Horizons observed Charon with the LEISA imaging spectrometer, part of the Ralph instrument (Reuter, D.C., Stern, S.A., Scherrer, J., et al. 2008, Space Science Reviews, 140, 129). Making use of high spatial resolution (better than 10 km/px) and spectral resolving power of 240 in the wavelength range 1.25-2.5 µm, and 560 in the range 2.1-2.25 µm, we report on an analysis of the phase of H2O ice on parts of Charon’s surface with a view to investigate the recent history and evolution of this small but intriguing object.This work was supported by NASA’s New Horizons project.
20. Recombination and dissociative recombination of H2+ and H3+ ions on surfaces with application to hydrogen negative ion sources
International Nuclear Information System (INIS)
Hiskes, J.R.; Karo, A.M.
1988-12-01
A four-step model for recombination and dissociative recombination of H 2 + and H 3 + ions on metal surfaces is discussed. Vibrationally excited molecules, H 2 (v''), from H 3 + recombination are produced in a broad spectrum that enhances the excited level distribution. The application of this latter process to hydrogen negative ion discharges is discussed. 5 refs., 3 figs., 1 tab
1. Emission of Lyman α radiation in H2 + H*(2s) collisions at thermal energies
International Nuclear Information System (INIS)
Stern, B.
1991-01-01
A previously-published study of the thermal-energy collision between H 2 and metastable H*(2s), which could lead to the emission of Lyman α radiation, is reconsidered to take into account possible polarization effects. The total was function of the system is expanded in terms of the molecular states of the intermediate complex H 2 * , which constitute the minimal basis of the four adiabatic states dissociating into H 2 + H*(n=2) where they are normally degenerate in energy. The results of the calculation show the existence, between three of those states, of average values of the separation distance R (R ≅ 10 atomic units) of long range (ΔR ≅ 2 au) electronic interactions which depend on the geometric form of the H 2 * molecule. From the molecular data the hypothesis of no longer considering H 2 with H*(2s) as a rigid rotator is postulated and justified, after a purely quantum mechanical treatment of the radial equations. The mean ratio of the (oscillating) polarization angular differential cross sections tot he elastic ones is found important (> ∼ 1/10). The inelastic phenomena are anticipated to be more marked in the ortho than in the para hydrogen at a low collision energy (75 meV). (15 refs., 2 tabs., 9 figs.)
2. Raman overtone intensities measured for H2
International Nuclear Information System (INIS)
Shelton, D.P.
1990-01-01
The Raman spectra of the vibrational fundamental, first overtone and second overtone transitions of the H 2 molecule were recorded using visible and ultraviolet argon--ion laser excitation. The ratios of transition polarizability matrix elements, α 01,21 /α 01,11 and α 01,31 /α 01,11 , were determined from the measured intensities of the Q(1) Raman lines v,J=0,1→v',1 for v'=1,2,3. The experimentally determined value of the Raman first overtone matrix element is in good agreement with the value from the best ab initio calculation
3. Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment
Science.gov (United States)
Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.
2011-01-01
Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.
4. Uranous nitrate production using PtO2 catalyst and H2/H2 gas mixtures
International Nuclear Information System (INIS)
Rao, K.S.; Shyamlal, R.; Narayanan, C.V.; Patil, A.R.; Ramanujam, A.; Kansra, V.P.; Balu, K.; Vaidya, V.N.
2001-01-01
The feasibility of producing near 100% uranous nitrate, the partitioning agent used in the spent fuel reprocessing by Purex process, by catalytically reducing uranyl nitrate with H 2 and H 2 gas mixtures was extensively studied. As near quantitative reduction of uranyl nitrate could be easily achieved in laboratory scale studies, pilot plant scale reduction of uranyl nitrate was also carried out and five litres of uranyl nitrate of 100 g/1 could be quantitatively reduced in one hour. (author)
5. The Orion Fingers: H2 Temperatures and Excitation in an Explosive Outflow
Science.gov (United States)
Youngblood, Allison; France, Kevin; Ginsburg, Adam; Hoadley, Keri; Bally, John
2018-04-01
We measure H2 temperatures and column densities across the Orion Becklin-Neugebauer/Kleinmann-Low (BN/KL) explosive outflow from a set of 13 near-infrared (IR) H2 rovibrational emission lines observed with the TripleSpec spectrograph on Apache Point Observatory’s 3.5 m telescope. We find that most of the region is well characterized by a single temperature (∼2000–2500 K), which may be influenced by the limited range of upper-energy levels (6000–20,000 K) probed by our data set. The H2 column density maps indicate that warm H2 comprises 10‑5–10‑3 of the total H2 column density near the center of the outflow. Combining column density measurements for co-spatial H2 and CO at T = 2500 K, we measure a CO/H2 fractional abundance of 2 × 10‑3 and discuss possible reasons why this value is in excess of the canonical 10‑4 value, including dust attenuation, incorrect assumptions on co-spatiality of the H2 and CO emission, and chemical processing in an extreme environment. We model the radiative transfer of H2 in this region with ultraviolet (UV) pumping models to look for signatures of H2 fluorescence from H I Lyα pumping. Dissociative (J-type) shocks and nebular emission from the foreground Orion H II region are considered as possible Lyα sources. From our radiative transfer models, we predict that signatures of Lyα pumping should be detectable in near-IR line ratios given a sufficiently strong source, but such a source is not present in the BN/KL outflow. The data are consistent with shocks as the H2 heating source.
6. Emission of hydrogen sulfide (H2S) at a waterfall in a sewer: study of main factors affecting H2S emission and modeling approaches.
Science.gov (United States)
Jung, Daniel; Hatrait, Laetitia; Gouello, Julien; Ponthieux, Arnaud; Parez, Vincent; Renner, Christophe
2017-11-01
Hydrogen sulfide (H 2 S) represents one of the main odorant gases emitted from sewer networks. A mathematical model can be a fast and low-cost tool for estimating its emission. This study investigates two approaches to modeling H 2 S gas transfer at a waterfall in a discharge manhole. The first approach is based on an adaptation of oxygen models for H 2 S emission at a waterfall and the second consists of a new model. An experimental set-up and a statistical data analysis allowed the main factors affecting H 2 S emission to be studied. A new model of the emission kinetics was developed using linear regression and taking into account H 2 S liquid concentration, waterfall height and fluid velocity at the outlet pipe of a rising main. Its prediction interval was estimated by the residual standard deviation (15.6%) up to a rate of 2.3 g H 2 S·h -1 . Finally, data coming from four sampling campaigns on sewer networks were used to perform simulations and compare predictions of all developed models.
7. Spatial-temporal evolution of self-organized loop-patterns on a water surface and a diffuse discharge in the gap
Science.gov (United States)
Li, Xuechen; Geng, Jinling; Jia, Pengying; Zhang, Panpan; Zhang, Qi; Li, Yaru
2017-11-01
Excited by an alternating current voltage, a patterned discharge and a diffuse discharge are generated in a needle to liquid configuration. Using an intensified charge-coupled device (ICCD), temporal evolution of the discharge between the two electrodes is investigated for the diffuse mode and the patterned mode, respectively. For the diffuse mode, the positive discharge is in a glow regime, and the negative discharge is in a Townsend discharge regime. For the patterned mode, the discharge always belongs to the Townsend discharge regime. Moreover, in the patterned mode, various patterns including the single loop, single loop with the surrounding corona, triple loops, and concentric loops with a central spot are observed on the water surface with the increasing positive peak-value of the applied voltage (Upp). Temporally resolved images of the loop-patterns are captured on the water surface. From the electrical measurements and the ICCD imaging, it is found that the loop pattern emerges after the discharge bridges the two electrodes. Then, it begins to evolve and finally degenerates with the decrease in the discharge current. The pattern does not disappear until the discharge quenches. Formation of the loop-patterns is attributed to the role of negative ions.
8. Nipple Discharge
Science.gov (United States)
... any unexpected nipple discharge evaluated by a doctor. Nipple discharge in men under any circumstances could be a problem and needs further evaluation. One or both breasts may produce a nipple discharge, either spontaneously or when you squeeze your ...
9. Hydrogen Dynamics in Cyanobacteria Dominated Microbial Mats Measured by Novel Combined H2/H2S and H2/O2 Microsensors
Directory of Open Access Journals (Sweden)
Karen Maegaard
2017-10-01
Full Text Available Hydrogen may accumulate to micromolar concentrations in cyanobacterial mat communities from various environments, but the governing factors for this accumulation are poorly described. We used newly developed sensors allowing for simultaneous measurement of H2S and H2 or O2 and H2 within the same point to elucidate the interactions between oxygen, sulfate reducing bacteria, and H2 producing microbes. After onset of darkness and subsequent change from oxic to anoxic conditions within the uppermost ∼1 mm of the mat, H2 accumulated to concentrations of up to 40 μmol L-1 in the formerly oxic layer, but with high variability among sites and sampling dates. The immediate onset of H2 production after darkening points to fermentation as the main H2 producing process in this mat. The measured profiles indicate that a gradual disappearance of the H2 peak was mainly due to the activity of sulfate reducing bacteria that invaded the formerly oxic surface layer from below, or persisted in an inactive state in the oxic mat during illumination. The absence of significant H2 consumption in the formerly oxic mat during the first ∼30 min after onset of anoxic conditions indicated absence of active sulfate reducers in this layer during the oxic period. Addition of the methanogenesis inhibitor BES led to increase in H2, indicating that methanogens contributed to the consumption of H2. Both H2 formation and consumption seemed unaffected by the presence/absence of H2S.
10. Advanced oxidation technology for H2S odor gas using non-thermal plasma
Science.gov (United States)
Tao, ZHU; Ruonan, WANG; Wenjing, BIAN; Yang, CHEN; Weidong, JING
2018-05-01
Non-thermal plasma technology is a new type of odor treatment processing. We deal with H2S from waste gas emission using non-thermal plasma generated by dielectric barrier discharge. On the basis of two criteria, removal efficiency and absolute removal amount, we deeply investigate the changes in electrical parameters and process parameters, and the reaction process of the influence of ozone on H2S gas removal. The experimental results show that H2S removal efficiency is proportional to the voltage, frequency, power, residence time and energy efficiency, while it is inversely proportional to the initial concentration of H2S gas, and ozone concentration. This study lays the foundations of non-thermal plasma technology for further commercial application.
11. Dynamical observation of lithium insertion/extraction reaction during charge-discharge processes in Li-ion batteries by in situ spatially resolved electron energy-loss spectroscopy.
Science.gov (United States)
Shimoyamada, Atsushi; Yamamoto, Kazuo; Yoshida, Ryuji; Kato, Takehisa; Iriyama, Yasutoshi; Hirayama, Tsukasa
2015-12-01
All-solid-state Li-ion batteries (LIBs) with solid electrolytes are expected to be the next generation devices to overcome serious issues facing conventional LIBs with liquid electrolytes. However, the large Li-ion transfer resistance at the electrode/solid-electrolyte interfaces causes low power density and prevents practical use. In-situ-formed negative electrodes prepared by decomposing the solid electrolyte Li(1+x+3z)Alx(Ti,Ge)(2-x)Si(3z)P(3-z)O12 (LASGTP) with an excess Li-ion insertion reaction are effective electrodes providing low Li-ion transfer resistance at the interfaces. Prior to our work, however, it had still been unclear how the negative electrodes were formed in the parent solid electrolytes. Here, we succeeded in dynamically visualizing the formation by in situ spatially resolved electron energy-loss spectroscopy in a transmission electron microscope mode (SR-TEM-EELS). The Li-ions were gradually inserted into the solid electrolyte region around 400 nm from the negative current-collector/solid-electrolyte interface in the charge process. Some of the ions were then extracted in the discharge process, and the rest were diffused such that the distribution was almost flat, resulting in the negative electrodes. The redox reaction of Ti(4+)/Ti(3+) in the solid electrolyte was also observed in situ during the Li insertion/extraction processes. The in situ SR-TEM-EELS revealed the mechanism of the electrochemical reaction in solid-state batteries. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
12. Molecular beam scattering experiments with polar molecules. 1. Differential elastic scattering of H2+NH3 and H2+H2O
International Nuclear Information System (INIS)
Bickes, R.W. Jr.; Scoles, G.; Smith, K.M.
1974-01-01
Differential elastic scattering cross sections with well resolved quantum oscillations have been measuremed for the systems H 2 +NH 3 and H 2 +H 2 O. Assuming a spherically symmetric interaction the data show that a simple spherical potential (i.e. Lennard-Jones) does not properly describe the scattering
13. A process for the thermochemical poduction of H2
International Nuclear Information System (INIS)
Norman, J.H.; Russell, J.L. Jr.; Porter, J.T. II; McCorkl, K.H.; Roemer, T.S.; Sharp, Robert.
1976-01-01
A process is described for the thermochemical production of H 2 from water. HI 3 and H 2 SO 4 are prepared by chemical reaction between I 2 , SO 2 and H 2 O. Then HI 3 is heated and decomposed into H 2 and I 2 . The heat is produced by a nuclear reactor [fr
14. Image-Based Measurement of H2O2 Reaction-Diffusion in Wounded Zebrafish Larvae.
Science.gov (United States)
Jelcic, Mark; Enyedi, Balázs; Xavier, João B; Niethammer, Philipp
2017-05-09
15. Electrochemical Quantification of Extracellular Local H2O2 Kinetics Originating from Single Cells.
Science.gov (United States)
Bozem, Monika; Knapp, Phillip; Mirčeski, Valentin; Slowik, Ewa J; Bogeski, Ivan; Kappl, Reinhard; Heinemann, Christian; Hoth, Markus
2017-05-15
H 2 O 2 is produced by all eukaryotic cells under physiological and pathological conditions. Due to its enormous relevance for cell signaling at low concentrations and antipathogenic function at high concentrations, precise quantification of extracellular local H 2 O 2 concentrations ([H 2 O 2 ]) originating from single cells is required. Using a scanning electrochemical microscope and bare platinum disk ultramicroelectrodes, we established sensitive long-term measurements of extracellular [H 2 O 2 ] kinetics originating from single primary human monocytes (MCs) ex vivo. For the electrochemical techniques square wave voltammetry, cyclic and linear scan voltammetry, and chronoamperometry, detection limits for [H 2 O 2 ] were determined to be 5, 50, and 500 nM, respectively. Following phorbol ester stimulation, local [H 2 O 2 ] 5-8 μm above a single MC increased by 3.4 nM/s within the first 10 min before reaching a plateau. After extracellular addition of H 2 O 2 to an unstimulated MC, the local [H 2 O 2 ] decreased on average by 4.2 nM/s due to degradation processes of the cell. Using the scanning mode of the setup, we found that H 2 O 2 is evenly distributed around the producing cell and can still be detected up to 30 μm away from the cell. The electrochemical single-cell measurements were validated in MC populations using electron spin resonance spectroscopy and the Amplex ® UltraRed assay. Innovation and Conclusion: We demonstrate a highly sensitive, spatially, and temporally resolved electrochemical approach to monitor dynamics of production and degradation processes for H 2 O 2 separately. Local extracellular [H 2 O 2 ] kinetics originating from single cells is quantified in real time. Antioxid. Redox Signal. 00, 000-000.
16. Concentration-Discharge relationships in a mine-impacted catchment, New River, Tennessee: Comparison across spatial and temporal scales using time-series analysis
Science.gov (United States)
Murphy, J.; Hornberger, G. M.
2009-12-01
Concentration-discharge (c-Q) relationships are useful in indentifying physical and chemical processes affecting stream water chemistry. Frequently used as a diagnostic tool, c-Q relationships can be used to infer particular mixing patterns that may occur in a catchment. However, much work has shown c-Q relationships are highly variable and often inconclusive, suggesting the catchment behavior they indicate cannot be readily recognized without supporting knowledge of system dynamics. For example, drainage area and location, in addition to changes in land use over time, affect many processes in catchments including flow routing and solute concentrations. The effect of spatial and temporal scales on c-Q relationships are explored using recursive time-series analysis of historic and recent water quality data. The New River encompasses 400 square miles of remote land on the Cumberland Plateau in middle Tennessee and is a major component of the headwaters of the Cumberland River. Current and historic coal mining, oil and gas extraction, and timber harvesting have impaired water quality in the watershed. Historically, the highest magnitude of degradation probably occurred during the mid-1900s with severe acid mine drainage throughout the watershed. In 1975, 56% of all coal mined in Tennessee was derived from the New River watershed. Over the past three decades most of the New River system has rebounded though some small tributaries still experience acid mine drainage and elevated metal loads. Sediment, in terms of quantity and sorption of metals, is currently considered the largest pollutant by many. Water pH is circum-neutral in the system and coal-mining pollution is best identified by elevated specific conductance and sulfate concentration. A combination of historic and recently collected water quality data were obtained for the Indian Fork, a small 4 square mile upland catchment in the New River watershed, and the New River main-stem, approximately 25 miles
17. Modelling electric discharge chemistry
International Nuclear Information System (INIS)
McFarlane, J.; Wren, J.C.
1991-07-01
The chemistry occurring in a electric discharge was modelled to predict how it would be influenced by discharge conditions. The discharge was characterized by a calculated Boltzmann electron-energy distribution, from which rate constants for electron-molecule processes in air were determined. These rate constants were used in a chemical kinetics calculation that also included reactions between neutral molecules, ions, free radicals and electronically excited species. The model describes how the discharge chemistry was influenced by humidity, electric field, electron number density, and concentrations of key reagents identified in the study. The use of an electric discharge to destroy airborne contaminant molecules was appraised, the targeted contaminants being CF 2 Cl 2 , HCN, and SO 2 . The modelling results indicate that an electric discharge should be able to remove HCN and CF 2 Cl 2 effectively, especially if the discharge conditions have been optimized. Effective destruction is achieved with a moderate electric field (over 1 x 10 -15 V.cm 2 ), a substantial electron number density (over 1 x 10 12 cm -3 ), and the presence of H 2 0 in the process air. The residence time in the discharge was also shown to be important in contaminant destruction. An attempt was made to explain the results of the electric discharge abatement of SO 2 , a component of a simulated flue-gas mixture. Results from the model indicate that the discharge parameters that increase the concentration of hydroxyl radical also increase the rate of decomposition of SO 2 . An objective of the study was to explain the apparent enhancement of SO 2 destruction by the presence of a small amount of NO 2 . It was thought that a likely explanation would be the stabilization of HOSO 2 , an important intermediate in the oxidation of SO 2 by NO 2 . (49 figs., 14 tabs., 75 refs.)
18. The synthesis of [2-3H2] taurine and [2-3H2] hypotaurine
International Nuclear Information System (INIS)
Fellman, J.H.
1981-01-01
The synthesis of [2- 3 H 2 ]-2-aminoethanesulfonate [2- 3 H]-taurine by the reduction of cyanomethanesulfonic acid with tritium gas is described. The conversion of [2- 3 H]-taurine and its 14 C and 35 S isotopic forms to 2-aminoethanesulfinate (hypotaurine) was accomplished by converting taurine to its corresponding sulfonyl chloride and reducing the latter with metallic zinc. (author)
19. H2O2 space shuttle APU
Science.gov (United States)
1975-01-01
A cryogenic H2-O2 auxiliary power unit (APU) was developed and successfully demonstrated. It has potential application as a minimum weight alternate to the space shuttle baseline APU because of its (1) low specific propellant consumption and (2) heat sink capabilities that reduce the amount of expendable evaporants. A reference system was designed with the necessary heat exchangers, combustor, turbine-gearbox, valves, and electronic controls to provide 400 shp to two aircraft hydraulic pumps. Development testing was carried out first on the combustor and control valves. This was followed by development of the control subsystem including the controller, the hydrogen and oxygen control valves, the combustor, and a turbine simulator. The complete APU system was hot tested for 10 hr with ambient and cryogenic propellants. Demonstrated at 95 percent of design power was 2.25 lb/hp-hr. At 10 percent design power, specific propellant consumption was 4 lb/hp-hr with space simulated exhaust and 5.2 lb/hp-hr with ambient exhaust. A 10 percent specific propellant consumption improvement is possible with some seal modifications. It was demonstrated that APU power levels could be changed by several hundred horsepower in less than 100 msec without exceeding allowable turbine inlet temperatures or turbine speed.
20. Methodological aspects of breath hydrogen (H2) analysis. Evaluation of a H2 monitor and interpretation of the breath H2 test
DEFF Research Database (Denmark)
Rumessen, J J; Kokholm, G; Gudmand-Høyer, E
1987-01-01
The reliability of end-expiratory hydrogen (H2) breath tests were assessed and the significance of some important pitfalls were studied, using a compact, rapid H2-monitor with electrochemical cells. The H2 response was shown to be linear and stable. The reproducibility of the breath collection...... were studied in 10 healthy adults during a 4-month period and they showed very marked inter- and intra-individual variability (16% above 40 p.p.m.). Initial peaks (early, short-lived H2 rises unrelated to carbohydrate malabsorption) were identified in 25% of the breath tests (in 4% above 20 p.......p.m). It is concluded that the technique used for interval sampling of end-expiratory breath samples for H2 concentration gives reliable results. The biological significance of H2 concentration increments can only be evaluated if the limitations of the technical procedures and the individual ability to produce H2...
1. Contribution of the pre-ionized H2 and the ionized H2+ subsystems to the HHG Spectra of H2 in intense laser fields
Science.gov (United States)
Iravani, Hossein; Sabzyan, Hassan; Vafaee, Mohsen; Buzari, Behnaz
2018-04-01
Contributions of the pre-ionized H2 (PI-H2) and ionized {{{H}}}2+ subsystems of the two-electron H2 system to its high-order harmonic generation in eight-cycle sin2-like ultrafast intense laser pulses are calculated and analyzed based on the solution of the time-dependent Schrödinger equation for the one-dimensional two-electronic H2 system with fixed nuclei. The laser pulses have λ = 390 and 532 nm wavelengths and I = 1 × 1014, 5 × 1014, 1 × 1015 and 5 × 1015 W cm‑2 intensities. It is found that at the two lower intensities, the PI-H2 subsystem dominantly produces the HHG spectra. However, at the two higher intensities, both PI-H2 and ionized {{{H}}}2+ subsystems contribute comparably to the HHG spectra. In the {{{H}}}2+ subsystem, the symmetry of the populations of {{{H}}}2+(I) and {{{H}}}2+(II) regions (left and right regions of {{{H}}}2+ subsystem) is broken by increasing the laser intensity. Complex patterns and even harmonics also appear at these two higher intensities. For instance, at 1 × 1015 W cm‑2 intensity and λ = 532 nm wavelength, the even harmonics are appeared near cutoff region. Interestingly, at 5 × 1015 W cm‑2 intensity and λ = 390 nm wavelength, the even harmonics replaced by the odd harmonics with red shift. At λ = 390 and 532 nm wavelengths and I = 1 × 1015 intensity, the two-electron cutoffs corresponding to nonsequential double-recombination with maximum return kinetic energy of 4.70Up are detected. The HHG spectra of the whole H2 system obtained with and without nuclear dynamics treated classically are approximately similar. However, at 1 × 1015 W cm‑2 intensity and λ = 532 nm wavelength, if we take into account nuclear dynamics, the even harmonics which are appeared near cutoff region, replaced by the odd harmonics with blue shift.
2. Deflagration-to-detonation transition and detonation propagation in H2-air mixtures with transverse concentration gradients
International Nuclear Information System (INIS)
Boeck, Lorenz Rupprecht
2015-01-01
Explosion of H 2 -air mixtures portrays a major hazard in nuclear reactors during severe loss-of-coolant accidents. Spatial gradients in H 2 concentration prevail in real-world scenarios. Mixture inhomogeneity can lead to significantly stronger explosions as compared to homogeneous mixtures. The present work identifies and quantifies the underlying physical mechanisms.
3. Schroedinger equation from 0 (h/2π) to o(h/2πinfinity)
International Nuclear Information System (INIS)
Voros, A.
1985-08-01
The Balian and Bloch idea, that the semiclassical treatment of the Schroedinger equation can be carried out exactly to all orders, o(h/2πinfinity), has been explicitly confirmed upon the time-independent equation with a polynomial potential V(q) in one degree of freedom. The global analytic structure of certain functions, which encode the full eigenvalue distribution, has indeed been computed in great detail with the complex WKB method, yielding a structure called a resurgence algebra. In the special case V(q) = q 2 sub(M), this leads to sum rules for the eigenvalues, which have been verified numerically. Inasmuch as the leading order 0(h/2π) of the WKB expansion amounts to the stationary phase evaluation of the Feynman path integral, it is a yet unsolved challenge to reproduce our results by an exact analysis of this path integral using a generalized saddle-point treatment
4. Structure of LaH(PO3H)2.3H2O
International Nuclear Information System (INIS)
Loukili, M.; Durand, J.; Larbot, A.; Cot, L.; Rafiq, M.
1991-01-01
Lanthanum hydrogen bis(hydrogenphosphite) trihydrate, LaH(Po 3 H) 2 .3H 2 O, M r =353.8, monoclinic, P2 1 /c, a=9.687 (3), b=7.138 (2), c=13.518 A, β=104.48 (3) deg, V=905.0 (5) A 3 , Z=4, D m =2.56 (2), D x =2.598 Mg m -3 , λ(MoKα)=0.71073 A, μ(MoKα)=5.103 mm -1 , F(000)=672, T=300 K, R=0.032 for 1018 independent observed reflections. The structure contains two phosphite anions connected by a hydrogen bond. The La 3+ cation is eight coordinated by seven O atoms from phosphite anions and one O atom of a water molecule. (orig.)
5. Behaviour of ceramic and metallic layers in a H2O-H2S
International Nuclear Information System (INIS)
Furtuna, I.; Mihailescu, M.; Deaconu, M.; Dinu, A.; Cotolan, V; Nedelcu, L.; Titescu, Gh.
1996-01-01
In the installations for heavy water production there exist zones where the action of aggressive working conditions combined with a severe variable hydrodynamical regime lead to the destruction of the pyrite protecting layer. An alternating solution for the protection of these zones is to cover them with ceramic or metallic layers. This work presents the results of the preliminary tests on G28-52 steel samples, covered with ceramic and metallic layers, in the working environment (H 2 O-H 2 S) of the heavy water production installations and in severe hydrodynamical conditions. On the basis of the results obtained in the experiments and from the examination of the microstructure of the layers prior and after testing, a phenomenological model was developed to explain the behaviour of the deposed layers. On the basis of this model the conditions that the layers must satisfy have been deduced to improve their behaviour in the working environment
6. State resolved rotational excitation cross-sections and rates in H2 + H2 collisions
International Nuclear Information System (INIS)
Sultanov, Renat A.; Guster, Dennis
2006-01-01
Rotational transitions in molecular hydrogen collisions are computed. The two most recently developed potential energy surfaces for the H 2 -H 2 system are used from the following works: [A.I. Boothroyd, P.G. Martin, W.J. Keogh, M.J. Peterson, J. Chem. Phys., 116 (2002) 666; P. Diep, J.K. Johnson, J. Chem. Phys., 113 (2000) 3480; P. Diep, J.K. Johnson, J. Chem. Phys., 112 (2000) 4465]. Cross-sections for rotational transitions 00 → 20, 22, 40, 42, 44 and corresponding rate coefficients are calculated using a quantum-mechanical approach. Results are compared for a wide range of kinetic temperatures 300 K ≤ T≤ 3000 K
7. DFT Calculation of IR Absorption Spectra for PCE-nH2O, TCE-nH2O, DCE-nH2O, VC-nH2O for Small and Water-Dominated Molecular Clusters
Science.gov (United States)
2017-10-31
VC-nH2O for Small and Water-Dominated Molecular Clusters October 31, 2017 Approved for public release; distribution is unlimited. L. Huang S.g...Calculation of IR Absorption Spectra for PCE-nH2O, TCE-nH2O, DCE-nH2O, VC-nH2O for Small and Water-Dominated Molecular Clusters L. Huang,1 S.G...nH2O molecular clusters using density function theory (DFT). DFT can provide interpretation of absorption spectra with respect to molecular
8. Shoulder replacement - discharge
Science.gov (United States)
Total shoulder arthroplasty - discharge; Endoprosthetic shoulder replacement - discharge; Partial shoulder replacement - discharge; Partial shoulder arthroplasty - discharge; Replacement - shoulder - discharge; Arthroplasty - shoulder - discharge
9. Hydrogen constituents of the mesosphere inferred from positive ions - H2O, CH4, H2CO, H2O2, and HCN
Science.gov (United States)
Kopp, E.
1990-01-01
The concentrations in the mesosphere of H2O, CH4, H2CO, H2O2, and HCN were inferred from data on positive ion compositions, obtained from one mid-latitude and four high-latitude rocket flights. The inferred concentrations were found to agree only partially with the ground-based microwave measurements and/or model prediction by Garcia and Solomon (1985). The CH4 concentration was found to vary between 70 and 4 ppb in daytime and 900 and 100 ppbv at night, respectively. Unexpectedly high H2CO concentrations were obtained, with H2CO/H2O ratios between 0.0006 and 0.1, and a mean HCN volume mixing ratio of 6 x 10 to the -10th was inferred.
10. Calculation of intermolecular potentials for H2H2 and H2−O2 dimers ab initio and prediction of second virial coefficients
International Nuclear Information System (INIS)
Pham Van, Tat; Deiters, Ulrich K.
2015-01-01
Highlights: • We construct the angular orientations of dimers H 2H 2 and H 2 −O 2 . • We calculate the ab initio intermolecular interaction energies for all built orientations. • Extrapolating the interaction energies to the complete basis set limit aug-cc-pV23Z. • We develop two 5-site ab initio intermolecular potentials of dimers H 2H 2 , H 2 −O 2 . • Calculating the virial coefficients of dimer H 2H 2 and H 2 −O 2 . - Abstract: The intermolecular interaction potentials of the dimers H 2H 2 and H 2 −O 2 were calculated from quantum mechanics, using coupled-cluster theory CCSD(T) and correlation-consistent basis sets aug-cc-pVmZ (m = 2, 3); the results were extrapolated to the basis set limit aug-cc-pV23Z. The interaction energies were corrected for the basis set superposition error with the counterpoise scheme. For comparison also Møller–Plesset perturbation theory (at levels 2–4) with the basis sets aug-cc-pVTZ were considered, but the results proved inferior. The quantum mechanical results were used to construct analytical pair potential functions. From these functions the second virial coefficients of hydrogen and the cross virial coefficients of the hydrogen–oxygen system were obtained by integration; in both cases corrections for quantum effects were included. The results agree well with experimental data, if available, or with empirical correlations
11. Widespread distribution of OH/H2O on the lunar surface inferred from spectral data.
Science.gov (United States)
Bandfield, Joshua L; Poston, Michael J; Klima, Rachel L; Edwards, Christopher S
2018-01-01
Remote sensing data from lunar orbiters have revealed spectral features consistent with the presence of OH or H 2 O on the lunar surface. Analyses of data from the Moon Mineralogy Mapper spectrometer onboard the Chandryaan-1 spacecraft have suggested that OH/H 2 O is recycled on diurnal timescales and persists only at high latitudes. However, the spatial distribution and temporal variability of the OH/H 2 O, as well as its source, remain uncertain. Here we incorporate a physics-based thermal correction into analysis of reflectance spectra from the Moon Mineralogy Mapper and find that prominent absorption features consistent with OH/H 2 O can be present at all latitudes, local times, and surface types examined. This suggests the widespread presence of OH/H 2 O on the lunar surface without significant diurnal migration. We suggest that the spectra are consistent with the production of OH in space weathered materials by the solar wind implantation of H + and formation of OH at crystal defect sites, as opposed to H 2 O sourced from the lunar interior. Regardless of the specific composition or formation mechanism, we conclude that OH/H 2 O can be present on the Moon under thermal conditions more wide-ranging than previously recognized.
12. THE DISTRIBUTION AND CHEMISTRY OF H2CO IN THE DM TAU PROTOPLANETARY DISK
International Nuclear Information System (INIS)
Loomis, Ryan A.; Öberg, Karin I.; Guzman, Viviana V.; Cleeves, L. Ilsedore; Andrews, Sean M.
2015-01-01
H 2 CO ice on dust grains is an important precursor of complex organic molecules (COMs). H 2 CO gas can be readily observed in protoplanetary disks and may be used to trace COM chemistry. However, its utility as a COM probe is currently limited by a lack of constraints on the relative contributions of two different formation pathways: on icy grain surfaces and in the gas phase. We use archival Atacama Large (sub-)Millimeter Array observations of the resolved distribution of H 2 CO emission in the disk around the young low-mass star DM Tau to assess the relative importance of these formation routes. The observed H 2 CO emission has a centrally peaked and radially broad brightness profile (extending out to 500 AU). We compare these observations with disk chemistry models with and without grain-surface formation reactions and find that both gas and grain-surface chemistry are necessary to explain the spatial distribution of the emission. Gas-phase H 2 CO production is responsible for the observed central peak, while grain-surface chemistry is required to reproduce the emission exterior to the CO snow line (where H 2 CO mainly forms through the hydrogenation of CO ice before being non-thermally desorbed). These observations demonstrate that both gas and grain-surface pathways contribute to the observed H 2 CO in disks and that their relative contributions depend strongly on distance from the host star
13. Application of H2O and UV/H2O2 processes for enhancing the biodegradability of reactive black 5 dye.
Science.gov (United States)
Kalpana, S Divya; Kalyanaraman, Chitra; Gandhi, N Nagendra
2011-07-01
14. Genomic constitution of an H-2:Tla variant leukemia.
Science.gov (United States)
Shen, F W; Chaganti, R S; Doucette, L A; Litman, G W; Steinmetz, M; Hood, L; Boyse, E A
1984-10-01
A TL+ leukemia of a (B6 X A)F1 hybrid mouse (H-2b/H-2a) was previously subjected to immunoselection against H-2a by passage in (B6 X A.SW)F1 mice (H-2b/H-2s). A variant leukemia line was obtained that serologically lacked not only the H-2a phenotype but also the TL phenotype determined by the linked cis Tlaa allele of strain A. The H-2b phenotype and the TL phenotype of the Tlab allele of the B6 strain, which is expressed only by leukemia cells, were retained by the variant. Southern blotting with an H-2 cDNA probe that identifies restriction fragment polymorphisms distinguishing alleles of the H-2 and Tla regions of the B6 and A strains indicates that both the H-2a and Tlaa alleles are missing from the genome of this H-2a:Tlaa negative variant. Since the variant has two apparently unaltered chromosomes 17, where the H-2:Tla complex is situated, and since the intensity of bands in Southern blotting is suggestive of H-2b homozygosity, it is considered that loss of the H-2a:Tlaa haplotype by the variant was accompanied by duplication of the H-2b:Tlab haplotype. The implied change from heterozygosity to homozygosity that the variant has undergone with respect to H-2:Tla was not paralleled by a similar change at the three other loci tested, since the variant retained heterozygosity for Pep-3 (chromosome 1), Gpi-1 (chromosome 7), and Es-1 (chromosome 8).
15. Laser photoelectron spectroscopy of MnH - 2, FeH - 2, CoH - 2, and NiH - 2: Determination of the electron affinities for the metal dihydrides
Science.gov (United States)
Miller, Amy E. S.; Feigerle, C. S.; Lineberger, W. C.
1986-04-01
The laser photoelectron spectra of MnH-2, FeH-2, CoH-2, and NiH-2 and the analogous deuterides are reported. Lack of vibrational structure in the spectra suggests that all of the dihydrides and their negative ions have linear geometries, and that the transitions observed in the spectra are due to the loss of nonbonding d electrons. The electron affinities for the metal dihydrides are determined to be 0.444±0.016 eV for MnH2, 1.049±0.014 eV for FeH2, 1.450±0.014 eV for CoH2, and 1.934±0.008 eV for NiH2. Electronic excitation energies are provided for excited states of FeH2, CoH2, and NiH2. Electron affinities and electronic excitation energies for the dideuterides are also reported. A limit on the electron affinity of CrH2 of ≥2.5 eV is determined. The electron affinities of the dihydrides directly correlate with the electron affinities of the high-spin states of the monohydrides, and with the electron affinities of the metal atoms. These results are in agreement with a qualitative model developed for bonding in the monohydrides.
16. Structural variations in the H-2 genes of AKR lymphomas.
NARCIS (Netherlands)
K. Hui; L. Minamide; N. Prandoni; H. Festenstein; F.G. Grosveld (Frank)
1986-01-01
textabstractK36.16 is an AKR H-2k thymoma which expresses an aberrant H-2Dd-like allospecificity, does not have a detectable amount of the H-2Kk syngeneic antigen and grows very easily in syngeneic mice. By DNA-mediated gene transfer experiments, we were able to obtain transformed clones which do
17. Beneficiation of titanium concentrate (anatase) by HCl/H2O2 leaching of impurities
International Nuclear Information System (INIS)
Trindade, R.B.E.; Teixeira, L.A.C.
1988-01-01
The HCl/H 2 O 2 leaching of impurities from a Brazilian anatase (TiO 2 ) concentrate has been investigated by factorial experimentations. The effects of the following variables were investigated: temperature (50-90 0 C), redox potential (with and without oxidizing agent-H 2 O 2 ) and HCl concentration (4-18,5%). The conclusions were based on the analyses of Fe, Ca, P, Al, Si, Th,Ce, La, U and Ti in the beneficiated concentrates. The final results recommended the following optimum operational conditions, in a four stage countercurrent leaching: in the 4 th reactor (discharge of beneficiated concentrate): HCl fed at 18.5%, T=75 0 C, and addition of H 2 O 2 at a potential (eH) of 850 mV; in the first three reactors: T=90 0 C; with no oxidizing agent. (author) [pt
18. Imaging of spatial distributions of the millimeter wave intensity by using visible continuum radiation from a discharge in a Cs–Xe mixture. Part I: Review of the method and its fundamentals
Energy Technology Data Exchange (ETDEWEB)
Gitlin, M. S., E-mail: gitlin@appl.sci-nnov.ru [Russian Academy of Sciences, Institute of Applied Physics (Russian Federation)
2017-02-15
The first part of the review is presented which is dedicated to the time-resolved method of imaging and measuring the spatial distribution of the intensity of millimeter waves by using visible continuum (VC) emitted by the positive column (PC) of a dc discharge in a mixture of cesium vapor with xenon. The review focuses on the operating principles, fundamentals, and applications of this new technique. The design of the discharge tube and experimental setup used to create a wide homogeneous plasma slab with the help of the Cs–Xe discharge at a gas pressure of 45 Torr are described. The millimeter-wave effects on the plasma slab are studied experimentally. The mechanism of microwave-induced variations in the VC brightness and the causes of violation of the local relation between the VC brightness and the intensity of millimeter waves are discussed. Experiments on the imaging of the field patterns of horn antennas and quasi-optical beams demonstrate that this technique can be used for good-quality imaging of millimeter-wave beams in the entire millimeter-wavelength band. The method has a microsecond temporal resolution and a spatial resolution of about 2 mm. Energy sensitivities of about 10 μJ/cm{sup 2} in the Ka-band and about 200 μJ/cm{sup 2} in the D-band have been demonstrated.
19. EERE-SBIR technology transfer opportunity. H2 Safety Sensors for H2
Energy Technology Data Exchange (ETDEWEB)
Johnston, Mariann R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-12-01
The Office of Energy Efficiency and Renewable Energy’s Fuel Cell Technologies Office (FCTO) works in partnership with industry (including small businesses), academia, and DOE's national laboratories to establish fuel cell and hydrogen energy technologies as economically competitive contributors to U.S. transportation needs. The work that is envisioned between the SBIR/STTR grantee and Los Alamos National Laboratory would involve Technical Transfer of Los Alamos Intellectual Property (IP) on Thin-film Mixed Potential Sensor (U.S. Patent 7,264,700) and associated know-how for H2 sensor manufacturing and packaging.
20. Global distribution of radiolytic H2 production in marine sediment and implications for subsurface life
Science.gov (United States)
Sauvage, J.; Flinders, A. F.; Spivack, A. J.; D'Hondt, S.
2017-12-01
1. Solid organic residues produced by irradiation of hydrocarbon-containing H2O and H2O/NH3 ices - Infrared spectroscopy and astronomical implications
International Nuclear Information System (INIS)
Khare, B.N.; Thompson, W.R.; Murray, B.G.J.P.T.; Chyba, C.F.; Sagan, C.
1989-01-01
Plasma-discharge irradiations were conducted for the methane clathrate expected in outer solar system satellites and cometary nuclei; also irradiated were ices prepared from other combinations of H 2 O with CH 4 , C 2 H 6 , or C 2 H 2 . Upon evaporation of the yellowish-to-tan irradiated ices, it is found that a colored solid film adheres to the walls of the reaction vessel at room temperature. These organic films are found to exhibit IR band identifiable with alkane, aldehide, alcohol, and perhaps alkene, as well as substituted aromatic functional groups. These spectra are compared with previous studies of UV- or photon-irradiated nonclathrated hydrocarbon-containing ices. 73 refs
2. Method for heavy-water production by H2S--H2O chemical exchange process
International Nuclear Information System (INIS)
Strathdee, G.G.
1978-01-01
The invention discloses a heavy water production stage in a bithermal H 2 S gas H 2 O liquid exchange plant wherein the cold tower is operated under temperature and pressure conditions such that H 2 S in the liquid phase is formed and is maintained in the separation units (sieve trays or plates) of the cold tower. It has been found that the presence of liquid H 2 S acts as an efficient anti-foaming agent
3. Dynamic investigation of the diffusion absorption refrigeration system NH3-H2O-H2
Directory of Open Access Journals (Sweden)
2017-09-01
Full Text Available This paper reports on a numerical and experimental study of a diffusion absorption refrigerator. The performance of the system is examined by computer simulation using MATLAB software and Engineering Equations Solver. A dynamic model is developed for each component of the system and solved numerically in order to predict the transient state of the diffusion absorption refrigeration. The experiment set included 0.04 m3 commercial absorption diffusion refrigerator working with the ammonia-water-hydrogen (NH3-H2O-H2 solution. The transient numerical results were validated with the experimental data. The investigations are focused on the dynamic profile of the temperature of each component. The results obtained agree with the experiment; the relative error between numerical and experimental models doesn’t exceed 15% for all temperatures of each component. The increase of the average ambient temperature from 23.04 °C to 32.56 °C causes an increase of the condensation temperature from 29.46 °C to 37.51 °C, and the best evaporation temperature obtained was 3 °C, with an ambient temperature of 23.04 °C. The results show that a minimum starting temperature of 152 °C and 63.8 W electric power are required to initiate the decrease of evaporation temperature.
4. Coordination polymers of scandium sulfate. Crystal structures of (H2Bipy)[Sc(H2O)(SO4)2]2·2H2O and (H2Bipy)[HSO4]2
International Nuclear Information System (INIS)
Petrosyants, S.P.; Ilyukhin, A.B.
2005-01-01
Compounds with general formula Cat x [Sc(H 2 O) z (SO 4 ) y ]·nH 2 O (Cat=NH 4 , H 2 Bipy (Bipy - 4,4'-bipyridine), HEdp (Edp - ethylene dipyridine)) identified on element analysis data and IR spectra are synthesized. X-ray diffraction analysis of (H 2 Bipy)[Sc(H 2 O)(SO 4 ) 2 ] 2 ·2H 2 O shows that in structure of the compound chains of ScO 6 octahedron and SO 4 tetrahedrons are joined in bands by tridentate coordination of sulfate ions. Bands form skeleton in endless emptiness of which there are H 2 Bipy 2+ cations [ru
5. H2S and polysulfide metabolism: Conventional and unconventional pathways.
Science.gov (United States)
Olson, Kenneth R
2018-03-01
It is now well established that hydrogen sulfide (H 2 S) is an effector of a wide variety of physiological processes. It is also clear that many of the effects of H 2 S are mediated through reactions with cysteine sulfur on regulatory proteins and most of these are not mediated directly by H 2 S but require prior oxidation of H 2 S and the formation of per- and polysulfides (H 2 S n , n = 2-8). Attendant with understanding the regulatory functions of H 2 S and H 2 S n is an appreciation of the mechanisms that control, i.e., both increase and decrease, their production and catabolism. Although a number of standard "conventional" pathways have been described and well characterized, novel "unconventional" pathways are continuously being identified. This review summarizes our current knowledge of both the conventional and unconventional. Copyright © 2017 Elsevier Inc. All rights reserved.
6. Increased H2CO production in the outer disk around HD 163296
Science.gov (United States)
Carney, M. T.; Hogerheijde, M. R.; Loomis, R. A.; Salinas, V. N.; Öberg, K. I.; Qi, C.; Wilner, D. J.
2017-09-01
Context. The gas and dust in circumstellar disks provide the raw materials to form planets. The study of organic molecules and their building blocks in such disks offers insight into the origin of the prebiotic environment of terrestrial planets. Aims: We aim to determine the distribution of formaldehyde, H2CO, in the disk around HD 163296 to assess the contribution of gas- and solid-phase formation routes of this simple organic. Methods: Three formaldehyde lines were observed (H2CO 303-202, H2CO 322-221, and H2CO 321-220) in the protoplanetary disk around the Herbig Ae star HD 163296 with ALMA at 0.5″ (60 AU) spatial resolution. Different parameterizations of the H2CO abundance were compared to the observed visibilities, using either a characteristic temperature, a characteristic radius or a radial power law index to describe the H2CO chemistry. Similar models were applied to ALMA Science Verification data of C18O. In each scenario, χ2 minimization on the visibilities was used to determine the best-fit model in each scenario. Results: H2CO 303-202 was readily detected via imaging, while the weaker H2CO 322-221 and H2CO 321-220 lines required matched filter analysis to detect. H2CO is present throughout most of the gaseous disk, extending out to 550 AU. An apparent 50 AU inner radius of the H2CO emission is likely caused by an optically thick dust continuum. The H2CO radial intensity profile shows a peak at 100 AU and a secondary bump at 300 AU, suggesting increased production in the outer disk. In all modeling scenarios, fits to the H2CO data show an increased abundance in the outer disk. The overall best-fit H2CO model shows a factor of two enhancement beyond a radius of 270 ± 20 AU, with an inner abundance (relative to H2) of 2 - 5 × 10-12. The H2CO emitting region has a lower limit on the kinetic temperature of T> 20 K. The C18O modeling suggests an order of magnitude depletion of C18O in the outer disk and an abundance of 4 - 12 × 10-8 in the inner disk
7. Spatially and temporally resolved detection of arsenic in a capillary dielectric barrier discharge by hydride generation high-resolved optical emission spectrometry
Czech Academy of Sciences Publication Activity Database
Burhenn, S.; Kratzer, Jan; Svoboda, Milan; Klute, F. D.; Michels, A.; Veža, D.; Franzke, J.
2018-01-01
Roč. 90, MAR (2018), s. 3424-3429 ISSN 0003-2700 R&D Projects: GA ČR GA17-04329S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * optical emission spectroscopy * arsenic hydride Subject RIV: CB - Analytical Chemistry , Separation OBOR OECD: Analytical chemistry Impact factor: 6.320, year: 2016
8. Spatially and temporally resolved detection of arsenic in a capillary dielectric barrier discharge by hydride generation high-resolved optical emission spectrometry
Czech Academy of Sciences Publication Activity Database
Burhenn, S.; Kratzer, Jan; Svoboda, Milan; Klute, F. D.; Michels, A.; Veža, D.; Franzke, J.
2018-01-01
Roč. 90, MAR (2018), s. 3424-3429 ISSN 0003-2700 R&D Projects: GA ČR GA17-04329S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * optical emission spectroscopy * arsenic hydride Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 6.320, year: 2016
9. XPS study on the surface reaction of uranium metal in H2 and H2-CO atmospheres
International Nuclear Information System (INIS)
Wang Xiaolin; Fu Yibei; Xie Renshou
1996-04-01
The surface reactions of uranium metal in H 2 and H 2 -CO atmospheres and the effects of temperature and CO on the hydriding reaction have been studied by X-ray photoelectron spectroscopy (XPS). The reaction between commercial H 2 and uranium metal at 25 degree C leads mainly to the further oxidation of surface layer of metal due to traces of water vapour. At 200 degree C, it may lead to the hydriding reaction of uranium and the hydriding increases with increasing the exposure of H 2 . Investigation indicates CO inhibits both the hydriding reaction and oxidation on the condition of H 2 -CO atmospheres. (13 refs., 10 figs.)
10. A detection method of negative pionlike particles from a H2 gas discharge plasma
International Nuclear Information System (INIS)
Uramoto, Joshin.
1996-02-01
The negative pionlike particles π - penetrate a metal (or insulator) plate if positive ions produced secondarily by H - ions, diffuse to the back of the plate. Thus, the π - particles are not detected by a usual beam collector of mass analyzer using a metal plate. In order to detect the π - particles, we must interrupt the diffusion of the positive ions to the back of the beam collector while the π - particles are confined inside the beam collector and changed into a multiplied electron current. (author)
11. Hydroxyl and molecular H2O diffusivity in a haploandesitic melt
Science.gov (United States)
Ni, Huaiwei; Xu, Zhengjiu; Zhang, Youxue
2013-02-01
H2O diffusion in a haploandesitic melt (a high-silica and Fe-free andesitic melt, NBO/T = 0.173) has been investigated at 1 GPa in a piston-cylinder apparatus. We adopted a double diffusion couple technique, in which one couple was composed of a nominally anhydrous glass with 0.01 wt.% H2O and a hydrous glass with 5.7 wt.% H2O, and the other contained the same nominally anhydrous glass and a hydrous glass with 3.3 wt.% H2O. Both couples were annealed in a single experimental run and hence experienced exactly the same P-T history, which is crucial for constraining the dependence of H2O diffusivity on water content. H2O concentration profiles were measured by both Fourier transform infrared (FTIR) microspectroscopy and confocal Raman microspectroscopy. Nearly identical profiles were obtained from Raman and FTIR methods for profile length >1 mm (produced at 1619-1842 K). By contrast, for profile lengths <100 μm (produced at 668-768 K), FTIR profiles show marked convolution effects compared to Raman profiles. A comparison between the short FTIR and Raman profiles indicates that the real spatial resolution (FWHM) of FTIR analyses is about 28 μm for a 7 μm wide aperture on ˜200 μm thick glasses. While the short profiles are not reliable for quantitative modeling, the long diffusion profiles at superliquidus temperatures can be fit reasonably well by a diffusivity model previously developed for felsic melts, in which molecular H2O (H2Om) is the only diffusive species and its diffusivity (D) increases exponentially with the content of total water (H2Ot). However, there is noticeable misfit of the data at low H2Ot concentrations, suggesting that OH diffusivity (DOH) cannot be neglected in this andesitic melt at high temperatures and low water contents. We hence develop a new fitting procedure that simultaneously fits both diffusion profiles from a single experimental run and accounts for the roles of both OH and H2Om diffusion. With this procedure, DOH/D is constrained
12. Detectability of H2-Ar and H2-Ne Dimers in Jovian Atmospheres
Directory of Open Access Journals (Sweden)
Young-Key Minn
1997-12-01
Full Text Available The detection of jovian hydrogen-hydrogen dimers through the clear telluric 2-micron window(Kim et al. 1995, Trafton et al. 1997 suggests possibility to detect noble gases in the form of dimer with hydrogen in jovian atmospheres. Since noble gases do not have spectral structures in the infrared, it has been difficult to derive their abundances in the atmospheres of jovian planets. If there is a significant component of noble gases other than helium in the jovian atmospheres. it might be detected through its dimer spectrum with hydrogen molecule. The relatively sharp spectral structures of hydrogen-argon and hydrogen-neon dimers compared with those of hydrogen-hydrogen dimers are useful for the detection, if an adequate signal-to-noise (S/N is obtained. If we use a large telescope, such as the Keck telescope, with a long exposure time (>24 hours, then H2-Ar spectral structure may be detected.
13. Absorption spectra of H2-H2 pairs in the fundamental band
International Nuclear Information System (INIS)
Meyer, W.; Borysow, A.; Frommhold, L.
1989-01-01
For the computation of the induced-dipole moment, the collisional complex consisting of two H 2 molecules is treated like one molecule in the self-consistent-field and size-consistent, coupled electron pair approximations that separates correctly at distant range. The basis set accounts for 95% of the correlation energies. The radial transition matrix elements of the induced-dipole components are obtained for the two cases v 1 =v 2 =0 and v 1 =0,v 2 =1, where the v i are the vibrational quantum numbers of the interacting H 2 molecules (i=1 or 2). The dependence of these elements on the most important rotational states (j 1 , j 1 ',j 2 ,j 2 '=0,...,3) involved is obtained and seen to be significant in the fundamental band. The results are recast in a simple, but accurate analytical form that is used in a quantum formalism for computations of the spectral moments (sum rules) and line shapes of the collision-induced absorption spectra of molecular hydrogen pairs in the infrared 2.4-μm band. The calculations are based on a proven isotropic potential model that we have extended to account for effects of vibrational excitations. Numerical consistency of the line-shape calculations with the sum rules is observed at the 1% level. The comparison of the computational results with the available measurements at temperatures from 20 to 300 K shows agreement within the estimated uncertainties of the best measurements (∼10%). This fact suggests that theory is capable of predicting these spectra reliably at temperatures for which no measurements exist, with an accuracy that compares favorably with that of good laboratory measurements
14. Synthesis and crystal structure of hydrogen phosphites RbH2PO3, CsH2PO3, and TlH2PO3
International Nuclear Information System (INIS)
Kosterina, E.V.; Troyanov, S.I.; Kemnits, Eh.; Aslanov, L.A.
2001-01-01
The crystal acid phosphites RbH 2 PO 3 , CsH 2 PO 3 and TlH 2 PO 3 were separated during reaction of Rb, Cs and Tl carbonates with phosphorous acid solution. The crystal structure of the compounds was analyzed by X-ray diffraction method at 150 K. CsH 2 PO 3 has a monoclinic system, a = 7.930(2), b = 8.929(2), c = 13.163(3) A, β = 104.84(3) Deg, V = 900.9(4) A 3 , Z 8, sp. gr. P2 1 /c, R 1 = 0.239. In the structure hydrogen bonds integrate the PHO 3 tetrahedrons in the unlimited zigzag chains [HPHO 3 ] n n- laying at the layers, which are alternate to the layers of metal cations. The layers of anion chains have a wavy form [ru
15. Untersuchungen am System NMMO/H2O/Cellulose
OpenAIRE
Cibik, T.
2003-01-01
Die vorliegende Arbeit befasst sich mit der Untersuchung des Zweistoffsystems N-Methylmorpholin-N-oxid (NMMO)/H2O und des Dreistoffsystems NMMO/H2O/Cellulose sowie mit der Herstellung und Charakterisierung von faserverstärkten Cellulosefolien. Das binäre System wird mittels Dynamischer Differenzkalorimetrie und Röntgenweitwinkel-Diffraktometrie untersucht und dadurch das Schmelzverhalten und die Phasenzusammensetzung dieses Systems im festen Zustand als Funktion des NMMO/H2O-Verhältnisses bes...
16. NIPPLE DISCHARGE
Directory of Open Access Journals (Sweden)
T. N. Bukharova
2008-01-01
Full Text Available According to the data available in the literature, as high as 50% of women have benign breast tumors frequently accompanied by nip- ple discharge. Nipple discharge may be serous, bloody, purulent, and colostric. The most common causes are breast abscess, injury, drugs, prolactinoma, intraductal pappiloma, ductal ectasia, intraductal cancer (not more than 10%.
17. Detonability of H2-air-diluent mixtures
International Nuclear Information System (INIS)
Tieszen, S.R.; Sherman, M.P.; Benedick, W.B.; Berman, M.
1987-06-01
This report describes the Heated Detonation Tube (HDT). Detonation cell width and velocity results are presented for H 2 -air mixtures, undiluted and diluted with CO 2 and H 2 O for a range of H 2 concentration, initial temperature and pressure. The results show that the addition of either CO 2 or H 2 O significantly increases the detonation cell width and hence reduces the detonability of the mixture. The results also show that the detonation cell width is reduced (detonability is increased) for increased initial temperature and/or pressure
18. Relative importance of H2 and H2S as energy sources for primary production in geothermal springs.
Science.gov (United States)
D'Imperio, Seth; Lehr, Corinne R; Oduro, Harry; Druschel, Greg; Kühl, Michael; McDermott, Timothy R
2008-09-01
Geothermal waters contain numerous potential electron donors capable of supporting chemolithotrophy-based primary production. Thermodynamic predictions of energy yields for specific electron donor and acceptor pairs in such systems are available, although direct assessments of these predictions are rare. This study assessed the relative importance of dissolved H(2) and H(2)S as energy sources for the support of chemolithotrophic metabolism in an acidic geothermal spring in Yellowstone National Park. H(2)S and H(2) concentration gradients were observed in the outflow channel, and vertical H(2)S and O(2) gradients were evident within the microbial mat. H(2)S levels and microbial consumption rates were approximately three orders of magnitude greater than those of H(2). Hydrogenobaculum-like organisms dominated the bacterial component of the microbial community, and isolates representing three distinct 16S rRNA gene phylotypes (phylotype = 100% identity) were isolated and characterized. Within a phylotype, O(2) requirements varied, as did energy source utilization: some isolates could grow only with H(2)S, some only with H(2), while others could utilize either as an energy source. These metabolic phenotypes were consistent with in situ geochemical conditions measured using aqueous chemical analysis and in-field measurements made by using gas chromatography and microelectrodes. Pure-culture experiments with an isolate that could utilize H(2)S and H(2) and that represented the dominant phylotype (70% of the PCR clones) showed that H(2)S and H(2) were used simultaneously, without evidence of induction or catabolite repression, and at relative rate differences comparable to those measured in ex situ field assays. Under in situ-relevant concentrations, growth of this isolate with H(2)S was better than that with H(2). The major conclusions drawn from this study are that phylogeny may not necessarily be reliable for predicting physiology and that H(2)S can dominate over H(2
19. Suspended sediment propagation in a long river reach: spatial and temporal dynamics of the Suspended Sediment Concentration-Water Discharge diagram for several hydrological events in the Northern French Alps.
Science.gov (United States)
Antoine, Germain; Jodeau, Magali; Camenen, Benoit; Esteves, Michel
2014-05-01
The relative propagation of water and suspended sediment is a key parameter to understand the suspended sediment transfers at the catchment scale. Several studies have shown the interest of performing detailed investigations of both temporal suspended sediment concentration (SSC) and water discharge signals. Most of them used temporal data from one measurement site, and classified hydrological events by studying the SSC curve as a function of water discharge (SSC-WD diagrams). Theoretical interpretations of these curves have been used to estimate the different sources of suspended sediment supply from sub-catchments, to evaluate the effect of seasons on the dynamics of suspended sediment, or to highlight the effect of a critical change at the catchment scale. However, few studies have focused on the signal propagation along the river channel. In this study, we analyze sampled data from a very well instrumented river reach in the Northern French Alps: the Arc-Isère River system. This gravel-bed river system is characterized by large concentrations of fines sediments, coming from the highly erodible mountains around. To control the hydraulic, sedimentary and chemical parameters from the catchment head, several gauging stations have been established since 2006. The continuous data measured at 4 gauging stations along 120 km of river have been analyzed to estimate the spatial and temporal dynamics of both SSC and water discharge. More precisely, about 40 major hydrological events have been sampled statistically between 2006 and 2012 from the data set and are analyzed in details. The study shows that the mean value of the propagation velocity is equal to 2 m/s and 3 m/s respectively for the SSC signal and the water discharge. These different propagation velocities imply that the suspended sediment mass is not only transported by the advection of the water at the river scale. The dispersion, erosion or deposition processes, and also the suspended sediment and discharge
20. (Solid + liquid) phase equilibria of (Ca(H2PO2)2 + CaCl2 + H2O) and (Ca(H2PO2)2 + NaH2PO2 + H2O) ternary systems at T = 323.15 K
International Nuclear Information System (INIS)
Cao, Hong-yu; Zhou, Huan; Bai, Xiao-qin; Ma, Ruo-xin; Tan, Li-na; Wang, Jun-min
2016-01-01
Graphical abstract: Solubility diagram of the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system at T = (323.15 and 298.15) K. - Highlights: • Phase diagrams of Ca 2+ -H 2 PO 2 − -Cl − -H 2 O, Ca 2+ -Na + -H 2 PO 2 − -H 2 O at 323.15 K were obtained. • Incompatible double salt of NaCa(H 2 PO 2 ) 3 in Ca 2+ -Na + -H 2 PO 2 − -H 2 O system was determined. • Density diagram of the corresponding liquid were simultaneously measured. - Abstract: Calcium hypophosphite has been widely used as an anti-corrosive agent, flame retardant, fertilizer, assistant for Ni electroless plating, and animal nutritional supplement. High purity calcium hypophosphite can be synthesized via the replacement reaction of sodium hypophosphite and calcium chloride. In this work, the (solid + liquid) phase equilibria of (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) and (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) ternary systems at T = 323.15 K were studied experimentally via the classical isothermal solubility equilibrium method, and the phase diagrams for these two systems were obtained. It was found that two solid salts of CaCl 2 ·2H 2 O and Ca(H 2 PO 2 ) 2 exist in the (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) system, and three salts of Ca(H 2 PO 2 ) 2 , NaH 2 PO 2 ·H 2 O and one incompatible double salt, NaCa(H 2 PO 2 ) 3 occur in the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system.
1. Optical spectrophotometry of Comet P/Giacobini-Zinner and emission profiles of H2O+
Science.gov (United States)
Strauss, M. A.; Mccarthy, P. J.; Spinrad, H.
1986-01-01
Two-dimensional CCD spectrograms were obtained of Comet P/Giacobini-Zinner (1984e) on five occasions between July and October 1985. Spatial emission profiles of H2O+ were extracted at 6198 angstroms (the strongest ionic line in the visible spectrum). This emission line traces the extent of the ion, or plasma, tail. The spectrographic slit was placed approximately along the trajectory of the ICE spacecraft on September 11, 1985; the resulting H2O+ profile has a full-width-half-maximum of about 5700 km, about three times that of the plasma density profile measured by ICE, and has a full-width-zero-intensity of about 30,000 km, very similar to the ICE values. H2O production rates for the comet are derived and compared with those of Comet P/Halley (1982i).
2. CFD Recombiner Modelling and Validation on the H2-Par and Kali-H2 Experiments
International Nuclear Information System (INIS)
Mimouni, S.; Mechitoua, N.; Ouraou, M.
2011-01-01
A large amount of Hydrogen gas is expected to be released within the dry containment of a pressurized water reactor (PWR), shortly after the hypothetical beginning of a severe accident leading to the melting of the core. According to local gas concentrations, the gaseous mixture of hydrogen, air and steam can reach the flammability limit, threatening the containment integrity. In order to prevent mechanical loads resulting from a possible conflagration of the gas mixture, French and German reactor containments are equipped with passive autocatalytic recombiners (PARs) which preventively oxidize hydrogen for concentrations lower than that of the flammability limit. The objective of the paper is to present numerical assessments of the recombiner models implemented in CFD solvers NEPTUNE C FD and Code S aturne. Under the EDF/EPRI agreement, CEA has been committed to perform 42 tests of PARs. The experimental program named KALI-H 2 , consists checking the performance and behaviour of PAR. Unrealistic values for the gas temperature are calculated if the conjugate heat transfer and the wall steam condensation are not taken into account. The combined effects of these models give a good agreement between computational results and experimental data
3. Accelerating Palladium Nanowire H2 Sensors Using Engineered Nanofiltration.
Science.gov (United States)
Koo, Won-Tae; Qiao, Shaopeng; Ogata, Alana F; Jha, Gaurav; Jang, Ji-Soo; Chen, Vivian T; Kim, Il-Doo; Penner, Reginald M
2017-09-26
The oxygen, O 2 , in air interferes with the detection of H 2 by palladium (Pd)-based H 2 sensors, including Pd nanowires (NWs), depressing the sensitivity and retarding the response/recovery speed in air-relative to N 2 or Ar. Here, we describe the preparation of H 2 sensors in which a nanofiltration layer consisting of a Zn metal-organic framework (MOF) is assembled onto Pd NWs. Polyhedron particles of Zn-based zeolite imidazole framework (ZIF-8) were synthesized on lithographically patterned Pd NWs, leading to the creation of ZIF-8/Pd NW bilayered H 2 sensors. The ZIF-8 filter has many micropores (0.34 nm for gas diffusion) which allows for the predominant penetration of hydrogen molecules with a kinetic diameter of 0.289 nm, whereas relatively larger gas molecules including oxygen (0.345 nm) and nitrogen (0.364 nm) in air are effectively screened, resulting in superior hydrogen sensing properties. Very importantly, the Pd NWs filtered by ZIF-8 membrane (Pd NWs@ZIF-8) reduced the H 2 response amplitude slightly (ΔR/R 0 = 3.5% to 1% of H 2 versus 5.9% for Pd NWs) and showed 20-fold faster recovery (7 s to 1% of H 2 ) and response (10 s to 1% of H 2 ) speed compared to that of pristine Pd NWs (164 s for response and 229 s for recovery to 1% of H 2 ). These outstanding results, which are mainly attributed to the molecular sieving and acceleration effect of ZIF-8 covered on Pd NWs, rank highest in H 2 sensing speed among room-temperature Pd-based H 2 sensors.
4. Self-Driven Photoelectrochemical Splitting of H2S for S and H2 Recovery and Simultaneous Electricity Generation.
Science.gov (United States)
Luo, Tao; Bai, Jing; Li, Jinhua; Zeng, Qingyi; Ji, Youzhi; Qiao, Li; Li, Xiaoyan; Zhou, Baoxue
2017-11-07
A novel, facile self-driven photoelectrocatalytic (PEC) system was established for highly selective and efficient recovery of H 2 S and simultaneous electricity production. The key ideas were the self-bias function between a WO 3 photoanode and a Si/PVC photocathode due to their mismatched Fermi levels and the special cyclic redox reaction mechanism of I - /I 3 - . Under solar light, the system facilitated the separation of holes in the photoanode and electrons in the photocathode, which then generated electricity. Cyclic redox reactions were produced in the photoanode region as follows: I - was transformed into I 3 - by photoholes or hydroxyl radicals, H 2 S was oxidized to S by I 3 - , and I 3 - was then reduced to I - . Meanwhile, H + was efficiently converted to H 2 in the photocathode region. In the system, H 2 S was uniquely oxidized to sulfur but not to polysulfide (S x n- ) because of the mild oxidation capacity of I 3 - . High recovery rates for S and H 2 were obtained up to ∼1.04 mg h -1 cm -1 and ∼0.75 mL h -1 cm -1 , respectively, suggesting that H 2 S was completely converted into H 2 and S. In addition, the output power density of the system reached ∼0.11 mW cm -2 . The proposed PEC-H 2 S system provides a self-sustaining, energy-saving method for simultaneous H 2 S treatment and energy recovery.
5. A model for radiolysis of water and aqueous solutions of H2, H2O2 and O2
International Nuclear Information System (INIS)
Ershov, B.G.; Gordeev, A.V.
2008-01-01
Kinetic model for the radiolysis of pure water describing the formation of H 2 , H 2 O 2 and O 2 and the radiation chemical transformations of aqueous solutions containing these compounds over a broad range of concentrations, pH, absorbed doses and dose rates is proposed and substantiated. The model includes a set of chemical reactions with optimized rate constants and the radiation chemical yields of radiolysis products. The model applicability to the description of the whole set of data on the radiation chemical transformations of water and aqueous solutions of H 2 , H 2 O 2 and O 2 is demonstrated
6. Endogenous mitigation of H2S inside of the landfills.
Science.gov (United States)
Fang, Yuan; Zhong, Zhong; Shen, Dongsheng; Du, Yao; Xu, Jing; Long, Yuyang
2016-02-01
Vast quantities of hydrogen sulfide (H2S) emitted from landfill sites require urgent disposal. The current study focused on source control and examined the migration and conversion behavior of sulfur compounds in two lab-scale simulated landfills with different operation modes. It aimed to explore the possible strategies and mechanisms for H2S endogenous mitigation inside of landfills during decomposition. It was found that the strength of H2S emissions from the landfill sites was dependent on the municipal solid waste (MSW) degradation speed and vertical distribution of sulfide. Leachate recirculation can shorten both the H2S influence period and pollution risk to the surrounding environment. H2S endogenous mitigation may be achieved by chemical oxidation, biological oxidation, adsorption, and/or precipitation in different stages. Migration and conversion mainly affected H2S release behavior during the initial stabilization phase in the landfill. Microbial activities related to sulfur, nitrogen, and iron can further promote H2S endogenous mitigation during the high reducing phase. Thus, H2S endogenous mitigation can be effectively enhanced via control of the aforementioned processes.
7. H2O Formation in C-rich AGB Winds
NARCIS (Netherlands)
Lombaert, R.; Decin, L.; Royer, P.; de Koter, A.; Cox, N.L.J.; De Ridder, J.; Khouri, T.; Agúndez, M.; Blommaert, J.A.D.L.; Gernicharo, J.; González-Alfonso, E.; Groenewegen, M.A.T.; Kerschbaum, F.; Neufeld, D.; Vandenbussche, B.; Waelkens, C.
2015-01-01
The Herschel detection of warm H2O vapor emission from C-rich winds of AGB stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm H2O formation. In the first, penetration of UV interstellar radiation through a clumpy circumstellar
8. TETRACHLORO ZINCATE (II) [H2pymo][ZnCl4
African Journals Online (AJOL)
assembly of a hexa-palladium bowl-shaped cluster, ... mimic the properties of conventional porous solids. A number of ... mg (2 mmol) of [H2pymo]Cl were ground ... Figure 2: The anion environment in the structure of [H2pymo]2[ZnCl4]. Figure ...
9. Robust H2 performance for sampled-data systems
DEFF Research Database (Denmark)
Rank, Mike Lind
1997-01-01
Robust H2 performance conditions under structured uncertainty, analogous to well known methods for H∞ performance, have recently emerged in both discrete and continuous-time. This paper considers the extension into uncertain sampled-data systems, taking into account inter-sample behavior. Convex...... conditions for robust H2 performance are derived for different uncertainty sets...
10. 45 CFR 1626.11 - H-2 agricultural workers.
Science.gov (United States)
2010-10-01
...) Other employment rights as provided in the worker's specific contract under which the nonimmigrant... 45 Public Welfare 4 2010-10-01 2010-10-01 false H-2 agricultural workers. 1626.11 Section 1626.11... ON LEGAL ASSISTANCE TO ALIENS § 1626.11 H-2 agricultural workers. (a) Nonimmigrant agricultural...
11. Charge transfer in H2+-H(1s) collisions
International Nuclear Information System (INIS)
Errea, L.F.; Macias, A.; Mendez, L.; Rabadan, I.; Riera, A.
2005-01-01
We present an ab initio study of H 2 + +H(1s) collisions at H 2 + impact energies between 0.4 and 50keV. Cross sections are obtained within the sudden approximation for rotation and vibration of the diatomic molecule. We have found that anisotropy effects are crucial to correctly describe this system in this energy range
12. The Role of Endogenous H(2)S in Cardiovascular Physiology
DEFF Research Database (Denmark)
Skovgaard, Nini; Gouliaev, Anja; Aalling, Mathilde
2011-01-01
Recent research has shown that the endogenous gas hydrogen sulphide (H(2)S) is a signalling molecule of considerable biological potential and has been suggested to be involved in a vast number of physiological processes. In the vascular system, H(2)S is synthesized from cysteine by cystathionine-...
13. Treatment of hospital laundry wastewater by UV/H2O2 process.
Science.gov (United States)
Zotesso, Jaqueline Pirão; Cossich, Eneida Sala; Janeiro, Vanderly; Tavares, Célia Regina Granhen
2017-03-01
Hospitals consume a large volume of water to carry out their activities and, hence, generate a large volume of effluent that is commonly discharged into the local sewage system without any treatment. Among the various sectors of healthcare facilities, the laundry is responsible for the majority of water consumption and generates a highly complex effluent. Although several advanced oxidation processes (AOPs) are currently under investigation on the degradation of a variety of contaminants, few of them are based on real wastewater samples. In this paper, the UV/H 2 O 2 AOP was evaluated on the treatment of a hospital laundry wastewater, after the application of a physicochemical pretreatment composed of coagulation-flocculation and anthracite filtration. For the UV/H 2 O 2 process, a photoreactor equipped with a low-pressure UV-C lamp was used and the effects of initial pH and [H 2 O 2 ]/chemical oxygen demand (COD) ratio on COD removal were investigated through a randomized factorial block design that considered the batches of effluent as blocks. The results indicated that the initial pH had no significant effect on the COD removal, and the process was favored by the increase in [H 2 O 2 ]/COD ratio. Color and turbidity were satisfactorily reduced after the application of the physicochemical pretreatment, and COD was completely removed by the UV/H 2 O 2 process under suitable conditions. The results of this study show that the UV/H 2 O 2 AOP is a promising candidate for hospital laundry wastewater treatment and should be explored to enable wastewater reuse in the washing process.
14. H2, CO, and dust absorption through cold molecular clouds
Science.gov (United States)
Lacy, John H.; Sneden, Chris; Kim, Hwihyun; Jaffe, Daniel Thomas
2017-06-01
We have made observations with IGRINS on the Harlan J. Smith telescope at McDonald Observatory of near-infrared absorption by H2, CO, and dust toward stars behind molecular clouds, primarily the TMC. Prior to these observations, the abundance of H2 in molecular clouds, relative to the commonly used tracer CO, had only been measured toward a few embedded stars, which may be surrounded by atypical gas. The new observations provide a representative sample of these molecules in cold molecular gas. We find N(H2)/Av ~ 0.9e+21, N(CO)/Av ~ 1.6e+17, and H2/CO ~ 6000. The measured H2/CO ratio is consistent with that measured toward embedded stars in various molecular clouds, but half that derived from mm-wave observations of CO emission and star counts or other determinations of Av.
15. Chemical absorption of H2S for biogas purification
Directory of Open Access Journals (Sweden)
Horikawa M.S.
2004-01-01
Full Text Available This work presents an experimental study of purification of a biogas by removal of its hydrogen sulphide (H2S content. The H2S was removed by means of chemical absorption in an iron-chelated solution catalyzed by Fe/EDTA, which converts H2S into elemental sulphur (S. Preparation of the catalyst solution and the results of biogas component absorption in the catalyst solution (0.2 mol/L are presented. These results are compared with those for physical absorption into pure water under similar conditions. Experimental results demonstrate that, under the same experimental conditions, a higher percentage of H2S can be removed in the catalytic solution than in water. In a continuous counter current using adequate flow-rate phases contact at room temperature and low gas pressure, the results demonstrate that is possible to totally remove the H2S from the biogas with the prepared catalytic solution.
16. Ileostomy - discharge
Science.gov (United States)
... dried fruits (such as raisins), mushrooms, chunky relishes, coconut, and some Chinese vegetables. Tips for when no ... ask your doctor Living with your ileostomy Low-fiber diet Small bowel resection - discharge Total colectomy or ...
17. GaAs micromachining in the 1 H2SO4:1 H2O2:8 H2O system. From anisotropy to simulation
Science.gov (United States)
Tellier, C. R.
2011-02-01
The bulk micromachining on (010), (110) and (111)A GaAs substrates in the 1 H2SO4:1 H2O2:8 H2O system is investigated. Focus is placed on anisotropy of 3D etching shapes with a special emphasis on convex and concave undercuts which are of prime importance in the wet micromachining of mechanical structures. Etched structures exhibit curved contours and more and less rounded sidewalls showing that the anisotropy is of type 2. This anisotropy can be conveniently described by a kinematic and tensorial model. Hence, a database composed of dissolution constants is further determined from experiments. A self-elaborated simulator which works with the proposed database is used to derive theoretical 3D shapes. Simulated shapes agree well with observed shapes of microstructures. The successful simulations open up two important applications for MEMS: CAD of mask patterns and meshing of simulated shapes for FEM simulation tools.
18. Influence of H2 reduction on lignin-based hard carbon performance in lithium ion batteries
International Nuclear Information System (INIS)
Chang, Zhen-zhen; Yu, Bao-jun; Wang, Cheng-yang
2015-01-01
ABSTRACT: Lignin as a by-product of fuel alcohol industry is used to prepare hard carbon materials by acetone extraction, stabilization in N 2 at 300 °C, carbonization in N 2 and subsequent H 2 reduction at 800 °C. The effect of H 2 reduction after carbonization process on the performances of the prepared samples is systematically studied and a simple mechanism is proposed. Excitingly, it is demonstrated that the process of H 2 reduction has a favorable influence on both structures and electrochemical performances of pyrolysis sample and an obvious improvement of capacity performance is obtained with reduction treatment. A first discharge/ charge capacity of 882.2/550.5 mA h g −1 (coulombic efficiency (CE) of 62.4%) is achieved at 0.1 C (1C = 372 mA g −1 ), and even after 200 cycles at 2 C a charge capacity of 228.8 mA h g −1 (about 92.8% retention ratio) remains and CE is above 99% during cycles for H 2 reduced sample. The fabulous electrochemical performance could be attributed to high purity of acetone-extracted lignin, low surface oxygen-containing functional groups and relatively high graphitization degree of reduction sample. In a word, both the simple pyrolysis process and excellent electrochemical performance make lignin-based hard carbon a promising anode material for high-capacity and high-stability lithium ion batteries (LIBs)
19. Electrochemical behavior of heavily cycled nickel electrodes in Ni/H2 cells containing electrolytes of various KOH concentrations
Science.gov (United States)
Lim, H. S.; Verzwyvelt, S. A.
1989-01-01
A study has been made of charge and discharge voltage changes with cycling of Ni/H2 cells containing electrolytes of various KOH concentrations. A study has also been made of electrochemical behavior of the nickel electrodes from the cycled Ni/H2 cells as a function of overcharge amounts. Discharge voltages depressed gradually with cycling for cells having high KOH concentrations (31 to 36 percent), but the voltages increased for those having low KOH concentrations (21 to 26 percent). To determine if there was a crystallographic change of the active material due to cycling, electrochemical behavior of nickel electrodes was studied in an electrolyte flooded cell containing either 31 or 26 percent KOH electrolyte as a function of the amount of overcharge. The changes in discharge voltage appear to indicate crystal structure changes of active material from gamma-phase to beta-phase in low KOH concentrations, and vice versa in high KOH concentration.
20. Fitting law for the density shift of Q(J) transitinos of H2 in H2-X (X: H2, He, N2) mixtures
International Nuclear Information System (INIS)
Michaut, X.; Berger, J.-P.; Sinclair, P.M.; Berger, H.
1998-01-01
A variety of fitting laws have been developed for the purpose of modelling broadening effects in collisional processes, but only a few have been proposed for modelling collision-induced lineshifts in molecules. We analysed accurate stimulated Raman data obtained in several H 2 -X mixtures (X: H 2 , He and N 2 ). For the first time, we show that an empirical law provides a very good representation of collisional lineshift coefficients in the range 300-1200 K and for J quantum number up to 9. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)
1. Synthesis and physicochemical investigation of vanadium tripolyphosphate, H2VP3O10·3H2O (3)
International Nuclear Information System (INIS)
Lyutsko, V.A.; Romanij, T.V.
1987-01-01
The new compound - vanadium dihydrotripolyphosphate, H 2 VP 3 O 10 x3H 2 O of the modification III has been prepared by interaction of the metalic vanadium and orthophosphoric acid at 483 K. It has been investigated by chemical analysis, thin layer chromatography, X-ray phase analysis, infrared spectroscopy and thermal analysis
2. A novel H2S/H2O2 fuel cell operating at the room temperature
Energy Technology Data Exchange (ETDEWEB)
Sanli, Ayse Elif [Gazi University (Turkey)], email: aecsanli@gmail.com; Aytac, Aylin [Department of Chemistry, Faculty of Science, Gazi University, Teknikokullar (Turkey)], email: aytaca@gazi.edu.tr
2011-07-01
This study concerns the oxidation mechanism of hydrogen sulfide and a fuel cell; acidic peroxide is used as the oxidant and basic hydrogen sulfide is the fuel. A solid state H2S/H2O2 stable fuel cell was produced at room temperature. A cell potential of 0.85 V was reached; this is quite remarkable in comparison to the H2S/O2 fuel cell potential of 0.85 V obtained at 850-1000 degree celsius. The hydrogen sulfide goes through an oxidation reaction in the alkaline fuel cell (H2S/H2O2 fuel cell) which opens up the possibility of using the cheaper nickel as a catalyst. As a result, the fuel cell becomes a potentially low cost technology. A further benefit from using H2S as the alkaline liquid H2S/H2O2 fuel cell, is that sulfide ions are oxidized at the anode, releasing electrons. Sulfur produced reacts with the other sulfide ions and forms disulfide and polysulfide ions in basic electrolytes (such as Black Sea water).
3. Ionization of H2O molecules through second order collisions in an argon-filled flow ionization chamber
International Nuclear Information System (INIS)
Leonhardt, J.
1976-01-01
In an argon-filled ionization chamber with a constant radionuclide radiation source, the ionization of H 2 O through second order collisions with 3sub(p) 2 states of argon excited by field-accelerated electrons is considered within the range of discharge caused by external potentials under atmospheric pressure. It is found that the logarithm of the change of ionization current is proportional to power 3/2 of the electric field strength. Possible formation mechanisms are discussed. Most probable is the ionization of H 2 O through collision with Ar 2 argon dimers originating from excited metastable atoms as a result of triple collision. The production cross section for H 2 O + has been estimated to be sigmasub(H 2 O) approximately 5x10 -15 . (author)
4. Properties of Highly Rotationally Excited H2 in Photodissociation Regions
Science.gov (United States)
Cummings, Sally Jane; Wan, Yier; Stancil, Phillip C.; Yang, Benhui H.; Zhang, Ziwei
2018-06-01
H2 is the dominant molecular species in the vast majority of interstellar environments and it plays a crucial role as a radiative coolant. In photodissociation regions, it is one of the primary emitters in the near to mid-infrared which are due to lines originating from highly excited rotational levels. However, collisional data for rotational levels j>10 are sparse, particularly for H2-H2 collisions. Utilizing new calculations for para-H2 and ortho-H2 collisional rate coefficients with H2 for j as high as 30, we investigate the effects of the new results in standard PDR models with the spectral simulation package Cloudy. We also perform Cloudy models of the Orion Bar and use Radex to explore rotational line ratio diagnostics. The resulting dataset of H2 collisional data should find wide application to other molecular environments. This work was support by Hubble Space Telescope grant HST-AR-13899.001-A and NASA grants NNX15AI61G and NNX16AF09G.
5. Vibrational inelasticity in H2 collisions with He and Li+
International Nuclear Information System (INIS)
Raczkowski, A.W.
1975-09-01
The partially averaged version of classical S-matrix theory was applied to three-dimensional collisions of H 2 with He and Li + . For H 2 -Li + , cross-sections for the de-excitation of H 2 from (n 1 ,j 1 ) = (1,0) to the ground vibrational manifold were computed at a total energy of 1.2 eV and compared to previously done coupled channel calculations of Schaefer and Lester. The agreement is very good. For H 2 -He, the Kutzelnigg-Tsapline interaction potential was extended to small atom-diatom separations, the ab initio points were then fit to an analytic form, and cross sections for the de-excitation of H 2 from the states (n 1 ,j 1 ), n 1 = 1, j 1 = 0,2,4 to the ground vibrational manifold were computed at total energies of .9, 1.1, 1.3 and 1.5 eV. For comparison, coupled channel calculations were also performed on the system at the same energies. The agreement was poorer than in the H 2 -Li + case, for identifiable reasons. The cross sections were used to compute rate constants and relaxation times for the H 2 -He system. Comparison of these results with the results of experiment and of other calculations shows good agreement, certainly within the expected errors. (7 figs., 30 refs., 3 tables)
6. Circumstellar H2O maser emission associated with four late-type stars
International Nuclear Information System (INIS)
Johnston, K.J.; Spencer, J.H.; Bowers, P.F.
1985-01-01
The positions and structure of H2O maser associated with four long-period stars were measured using the VLA, and the results are discussed. The four stars observed were: RX Boo; R Aq1; RR Aq1; and NML Cyg. The spatial resolution of the VLA measurements was 0.07 arcsec. The H2O maser emission features appear as unresolved knots distributed over an area of no more than 0.4 arcsec. The velocity and spatial characteristics of the maser regions in R Aq1 and RR Aq1 were found to change considerably over time. The estimated sizes of the H2O maser emission were 8 x 10 to the 14th for RX Boo, R Aq1, and RR Aq1. The supergiant star NML Cyg had the largest maser region (10 to the 16th) which is comparable to that of VY CMa. The positional accuracy for individual maser features ranged between 0.03 and 0.09 arcsec. However, the precise location of the maser emission relative to the stellar photocenter did not fit the velocity and spatial distributions of the emission and therefore may be inappropriate as a standard for comparisons of stellar reference frames. 20 references
7. Extension of a He-H2 potential energy surface
International Nuclear Information System (INIS)
Raczkowski, A.W.; Lester, W.A. Jr.
1977-01-01
The CI surface of Tsapline and Kutzelnigg is extended to smaller H 2 -He separations. Defining R as the H 2 -He distance, r as the H 2 separation, and γ as the angle between them, the ab initio values are fit to a Legendre series in cosγ retaining the first three (even) terms with the coefficients given as analytic functions of R and r to facilitate semiclassical scattering computations. The fit is quantitative for 1.0 approximately r/2+1. (Auth.)
8. Inelastic neutron scattering of H2 adsorbed in HKUST-1
International Nuclear Information System (INIS)
Liu, Y.; Brown, C.M.; Neumann, D.A.; Peterson, V.K.; Kepert, C.J.
2007-01-01
A series of inelastic neutron scattering (INS) investigations of hydrogen adsorbed in activated HKUST-1 (Cu 3 (1,3,5-benzenetricarboxylate) 2 ) result in INS spectra with rich features, even at very low loading ( 2 :Cu). The distinct inelastic features in the spectra show that there are three binding sites that are progressively populated when the H 2 loading is less than 2.0 H 2 :Cu, which is consistent with the result obtained from previous neutron powder diffraction experiments. The temperature dependence of the INS spectra reveals the relative binding enthalpies for H 2 at each site
9. Photoionization of H2O at high resolution
International Nuclear Information System (INIS)
Dehmer, P.M.; Chupka, W.A.
1978-01-01
The relative photoionization cross sections for the formation of H 2 O + , OH + , and H + from H 2 O were measured at high wavelength resolution using a 3-meter photoionization mass spectrometer equipped with a quadrupole mass flter and a 1-meter photoionization mass spectrometer equipped with a 12-inch radius, 60 0 sector magnetic mass spectrometer. Discrete structure in the parent ion photoionization efficiency curve is interpreted in terms of Rydberg series converging to excited states of the H 2 O + ion. 9 references
10. H2O masers in star-forming regions
International Nuclear Information System (INIS)
Downes, D.
1985-01-01
Water vapour near star forming regions was first detected by Cheung et al. (1969) and shortly thereafter was recognised to be maser emission. In spite of this 15 year history of H 2 O observations, the problem of interpreting such strong H 2 O masers as W49 and Orion is still very acute. Not one of the models now available can explain in an unconstrained fashion why a very large maser flux can emanate from clouds of such small size. Whereas some models proposed to explain OH masers have retained their plausibility under the pressure of new observations, H 2 O models have not. The author outlines the background of the H 2 O problem, stating that the strongest of the masers discovered are still not satisfactorily explained today. (Auth.)
11. H2S: a universal defense against antibiotics in bacteria.
Science.gov (United States)
Shatalin, Konstantin; Shatalina, Elena; Mironov, Alexander; Nudler, Evgeny
2011-11-18
Many prokaryotic species generate hydrogen sulfide (H(2)S) in their natural environments. However, the biochemistry and physiological role of this gas in nonsulfur bacteria remain largely unknown. Here we demonstrate that inactivation of putative cystathionine β-synthase, cystathionine γ-lyase, or 3-mercaptopyruvate sulfurtransferase in Bacillus anthracis, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli suppresses H(2)S production, rendering these pathogens highly sensitive to a multitude of antibiotics. Exogenous H(2)S suppresses this effect. Moreover, in bacteria that normally produce H(2)S and nitric oxide, these two gases act synergistically to sustain growth. The mechanism of gas-mediated antibiotic resistance relies on mitigation of oxidative stress imposed by antibiotics.
12. Extended Structures of Planetary Nebulae Detected in H2 Emission
Science.gov (United States)
Fang, Xuan; Zhang, Yong; Kwok, Sun; Hsia, Chih-Hao; Chau, Wayne; Ramos-Larios, Gerardo; Guerrero, Martín A.
2018-06-01
We present narrowband near-infrared images of a sample of 11 Galactic planetary nebulae (PNe) obtained in the H2 2.122 μm and Brγ 2.166 μm emission lines and the K c 2.218 μm continuum. These images were collected with the Wide-field Infrared Camera on the 3.6 m Canada–France–Hawaii Telescope (CFHT); their unprecedented depth and wide field of view allow us to find extended nebular structures in H2 emission in several PNe, some of these being the first detection. The nebular morphologies in H2 emission are studied in analogy with the optical images, and indication of stellar wind interactions is discussed. In particular, the complete structure of the highly asymmetric halo in NGC 6772 is witnessed in H2, which strongly suggests interaction with the interstellar medium. Our sample confirms the general correlation between H2 emission and the bipolarity of PNe. The knotty or filamentary fine structures of the H2 gas are resolved in the inner regions of several ring-like PNe, also confirming the previous argument that H2 emission mostly comes from knots or clumps embedded within fully ionized material at the equatorial regions. Moreover, the H2 image of the butterfly-shaped Sh 1-89, after removal of field stars, clearly reveals a tilted ring structure at the waist. These high-quality CFHT images justify follow-up detailed morphokinematic studies that are desired in order to deduce the true physical structures of a few PNe in the sample. Based on observations obtained with WIRCam, a joint project of CFHT, Taiwan, Korea, Canada, and France, at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.
13. Are CO Observations of Interstellar Clouds Tracing the H2?
Science.gov (United States)
Federrath, Christoph; Glover, S. C. O.; Klessen, R. S.; Mac Low, M.
2010-01-01
Interstellar clouds are commonly observed through the emission of rotational transitions from carbon monoxide (CO). However, the abundance ratio of CO to molecular hydrogen (H2), which is the most abundant molecule in molecular clouds is only about 10-4. This raises the important question of whether the observed CO emission is actually tracing the bulk of the gas in these clouds, and whether it can be used to derive quantities like the total mass of the cloud, the gas density distribution function, the fractal dimension, and the velocity dispersion--size relation. To evaluate the usability and accuracy of CO as a tracer for H2 gas, we generate synthetic observations of hydrodynamical models that include a detailed chemical network to follow the formation and photo-dissociation of H2 and CO. These three-dimensional models of turbulent interstellar cloud formation self-consistently follow the coupled thermal, dynamical and chemical evolution of 32 species, with a particular focus on H2 and CO (Glover et al. 2009). We find that CO primarily traces the dense gas in the clouds, however, with a significant scatter due to turbulent mixing and self-shielding of H2 and CO. The H2 probability distribution function (PDF) is well-described by a log-normal distribution. In contrast, the CO column density PDF has a strongly non-Gaussian low-density wing, not at all consistent with a log-normal distribution. Centroid velocity statistics show that CO is more intermittent than H2, leading to an overestimate of the velocity scaling exponent in the velocity dispersion--size relation. With our systematic comparison of H2 and CO data from the numerical models, we hope to provide a statistical formula to correct for the bias of CO observations. CF acknowledges financial support from a Kade Fellowship of the American Museum of Natural History.
14. Hydrogen degradation of the 26H2MF alloy steel in H2SO4 and hydrocarbon environments
International Nuclear Information System (INIS)
Zielinski, A.; Swieczko-Zurek, B.; Michaliak, P.
2004-01-01
The Polish 26H2M alloy steel has been subjected to different heat treatment resulting in different microstructure and fracture appearance. The slow strain rate tests have been made on smooth round specimens in diluted sulphuric acid, boiler fuel and used mineral machine oil. The 26H2MF steel has become relatively immune in neutral boiler fuel and mineral oil and been heavily suffered from hydrogen degradation in acidic environment. The results demonstrate that the 26H2MF steel is highly susceptible to hydrogen degradation but in absence of stress raisers the increased hydrogen absorption in hydrocarbons can cause only small loss of its plasticity. (author) >>>
15. Ab initio study of MgH2 formation
International Nuclear Information System (INIS)
Novakovic, Nikola; Matovic, Ljiljana; Novakovic, Jasmina Grbovic; Manasijevic, Miodrag; Ivanovic, Nenad
2009-01-01
Even if there is considerable literature dealing with structure and properties of MgH 2 compound there are still some uncertain details about nature of bonding governing its formation and decomposition. In order to better understand the processes essential for absorption and desorption of MgH 2 , ab initio DFT based calculations of rutile MgH 2 compound, elemental hcp-Mg, and three different hypothetical hcp-Mg-derived hydrides are performed. Our findings show that all structures are unstable, and that MgH (Wurtzite) is a closest possible candidate for intermediate phase between the hcp-Mg and MgH 2 at 1:1 stoichiometry. An alternative hydration pathway is suggested, including promotion of hcp-Mg to bcc-Mg and consecutive transformation to rutile MgH 2 by means of hydrogen incorporation into Mg matrix. Rutile MgH 2 calculations with various hydrogen vacancies concentration are performed. Calculation shows that at high hydrogen concentration close to 1:2, stable substoichiometric hydride is possible. Calculation also shows that high vacancy (low hydrogen) concentration favors bcc-Mg 2 H over rutile Mg 2 H structure.
16. H2S mediated thermal and photochemical methane activation
Science.gov (United States)
Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric
2013-01-01
Sustainable, low temperature methods of natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) in mixture with methane, CH4, altogether deemed as sub-quality or “sour” gas. We propose a unique method for activating this “sour” gas to form a mixture of sulfur-containing hydrocarbon intermediates, CH3SH and CH3SCH3, and an energy carrier, such as H2. For this purpose, we computationally investigated H2S mediated methane activation to form a reactive CH3SH species via direct photolysis of sub-quality natural gas. Photoexcitation of hydrogen sulfide in the CH4+H2S complex results in a barrier-less relaxation via a conical intersection to form a ground state CH3SH+H2 complex. The resulting CH3SH can further be heterogeneously coupled over acidic catalysts to form higher hydrocarbons while the H2 can be used as a fuel. This process is very different from a conventional thermal or radical-based processes and can be driven photolytically at low temperatures, with enhanced controllability over the process conditions currently used in industrial oxidative natural gas activation. Finally, the proposed process is CO2 neutral, as opposed to the currently industrially used methane steam reforming (SMR). PMID:24150813
17. H2S-mediated thermal and photochemical methane activation.
Science.gov (United States)
Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric V
2013-12-02
Sustainable, low-temperature methods for natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) mixed with methane, deemed altogether as sub-quality or "sour" gas. We propose a unique method of activation to form a mixture of sulfur-containing hydrocarbon intermediates, CH3SH and CH3SCH3 , and an energy carrier such as H2. For this purpose, we investigated the H2S-mediated methane activation to form a reactive CH3SH species by means of direct photolysis of sub-quality natural gas. Photoexcitation of hydrogen sulfide in the CH4 + H2S complex resulted in a barrierless relaxation by a conical intersection to form a ground-state CH3SH + H2 complex. The resulting CH3SH could further be coupled over acidic catalysts to form higher hydrocarbons, and the resulting H2 used as a fuel. This process is very different from conventional thermal or radical-based processes and can be driven photolytically at low temperatures, with enhanced control over the conditions currently used in industrial oxidative natural gas activation. Finally, the proposed process is CO2 neutral, as opposed to the current industrial steam methane reforming (SMR). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
18. Discharge Dialogue
DEFF Research Database (Denmark)
Horsbøl, Anders
2012-01-01
For several years, efforts have been made to strengthen collaboration between health professionals with different specializations and to improve patient transition from hospital to home (care). In the Danish health care system, these efforts have concentrated on cancer and heart diseases, whereas...... coordinator, employed at the hospital, is supposed to anticipate discharge and serve as mediator between the hospital and the municipal home care system. Drawing on methods from discourse and interaction analysis, the paper studies the practice of the discharge coordinator in two encounters between patients...... how the home context provides different resources for identification of patient needs and mutual decision making....
19. Realisation and crossed molecular beams study of H2/O chemical reactions at several excited states
International Nuclear Information System (INIS)
Marx, Jacqueline
1986-01-01
This work is devoted to the study of the reactive collision O + H 2 OH + H in a crossed beam experiment. This process including several channels taken a part in the chemistry of the upper atmosphere as well as in the combustion of hydrogen. According to the electronic or vibrational state of the reactants, the OH radical is produced in its ground electronic state OH (X 2 π) or in its first excited state OH (A 2 Σ + ). When the reactants are in their ground state, the reaction is endothermic in the conditions of the experiment (center of mass kinetic energy ≅ 0.12 eV). The following reactions have been obtained: O( 1 D) +H 2 (v=O) → OH (X 2 π) +H( 2 S) and O( 1 D) +H 2 (v≥5) → OH (A 2 Σ + ) +H( 2 S). The atomic oxygen is produced in its excited state O( 1 D) in a radio-frequency discharge which dissociates the molecular oxygen seeded in a carrier gas (He or Ar) and the hydrogen molecules are excited vibrationally by electron bombardment. The first reaction is studied by time-of-flight measurements. In this way, it has been possible to observe the different vibrational levels on which the OH radical is produced. The analysis of this vibrational distribution shows the competition between the abstraction and insertion-dissociation mechanisms. In the second reaction, the analysis of the spontaneous fluorescence of OH (A 2 Σ + ) reveals a very hot and non-Boltzmann rotational excitation. (author) [fr
20. Unexpected spatial impact of treatment plant discharges induced by episodic hydrodynamic events: Modelling Lagrangian transport of fine particles by Northern Current intrusions in the bays of Marseille (France).
Science.gov (United States)
Millet, Bertrand; Pinazo, Christel; Banaru, Daniela; Pagès, Rémi; Guiart, Pierre; Pairaud, Ivane
2018-01-01
Our study highlights the Lagrangian transport of solid particles discharged at the Marseille Wastewater Treatment Plant (WWTP), located at Cortiou on the southern coastline. We focused on episodic situations characterized by a coastal circulation pattern induced by intrusion events of the Northern Current (NC) on the continental shelf, associated with SE wind regimes. We computed, using MARS3D-RHOMA and ICHTHYOP models, the particle trajectories from a patch of 5.104 passive and conservative fine particles released at the WWTP outlet, during 2 chosen representative periods of intrusion of the NC in June 2008 and in October 2011, associated with S-SE and E-SE winds, respectively. Unexpected results highlighted that the amount of particles reaching the vulnerable shorelines of both northern and southern bays accounted for 21.2% and 46.3% of the WWTP initial patch, in June 2008 and October 2011, respectively. Finally, a conceptual diagram is proposed to highlight the mechanisms of dispersion within the bays of Marseille of the fine particles released at the WWTP outlet that have long been underestimated.
1. Reticular V2O5·0.6H2O Xerogel as Cathode for Rechargeable Potassium Ion Batteries.
Science.gov (United States)
Tian, Bingbing; Tang, Wei; Su, Chenliang; Li, Ying
2018-01-10
Potassium ion batteries (KIBs), because of their low price, may exhibit advantages over lithium ion batteries as potential candidates for large-scale energy storage systems. However, owing to the large ionic radii of K-ions, it is challenging to find a suitable intercalation host for KIBs and thus the rechargeable KIB electrode materials are still largely unexplored. In this work, a reticular V 2 O 5 ·0.6H 2 O xerogel was synthesized via a hydrothermal process as a cathode material for rechargeable KIBs. Compared with the orthorhombic crystalline V 2 O 5 , the hydrated vanadium pentoxide (V 2 O 5 ·0.6H 2 O) exhibits the ability of accommodating larger alkali metal ions of K + because of the enlarged layer space by hosting structural H 2 O molecules in the interlayer. By intercalation of H 2 O into the V 2 O 5 layers, its potassium electrochemical activity is significantly improved. It exhibits an initial discharge capacity of ∼224.4 mA h g -1 and a discharge capacity of ∼103.5 mA h g -1 even after 500 discharge/charge cycles at a current density of 50 mA g -1 , which is much higher than that of the V 2 O 5 electrode without structural water. Meanwhile, X-ray diffraction and X-ray photoelectron spectroscopy combined with energy dispersive spectroscopy techniques are carried out to investigate the potassiation/depotassiation process of the V 2 O 5 ·0.6H 2 O electrodes, which confirmed the potassium intercalation storage mechanisms of this hydrated material. The results demonstrate that the interlayer-spacing-enlarged V 2 O 5 ·0.6H 2 O is a promising cathode candidate for KIBs.
2. Plasmas pour la destruction de l'H2S et des mercaptans Plasmas for Destruction of H2s and Mercaptans
Directory of Open Access Journals (Sweden)
Czernichowski A.
2006-12-01
media for an oxidation of H2S or CH3SH diluted in air, CO2 or steam in order to convert them into less malodorous SO2. The product can be then used as a reagent in a Claus-like process in presence of water to convert twice as much of initial pollutants into elemental sulfur. A particular attention is devoted to the gliding electrical discharges (GlidArc. These powerful discharges produce non-thermal plasma, which activates oxidation reactions. Most of experiments were performed using one and four-stage GlidArc-I reactors. Air-diluted sulfides at initial concentrations up to 1% (H2S or 0. 1% (CH3SH were processed at up to 70 m3(n/h flow rate and 5 kW power scale. The tests were done at 1 atm. Up to 100% clean-up was obtained at a quite low energy cost depending on initial pollutant concentration: roughly 1000 kWh per 1 kg of removed sulfur at 100 ppm of H2S, but only 10 kWh/kg for 1% initial H2S in air. Almost the same energies were needed in the case of CH3SH-air mixtures. Using a very simple washing column in which water saturates with the produced SO2 and so captures unprocessed H2S we cut these process energy by three, avoiding the SO2 emission and obtaining non-toxic sulfur. New development based on GlidArc-ll brush-like electric discharges is also presented. Preliminary tests are very promising as the energy expense is already cut down by a factor of two with respect to the GlidArc-I devices. Up to industrial scale tests can be therefore performed.
3. A Critical Review of Models of the H-2/H2O/Ni/SZ Electrode Kinetics
DEFF Research Database (Denmark)
Mogensen, Mogens Bjerg; Høgh, Jens Valdemar Thorvald; Hansen, Karin Vels
2007-01-01
Various models of the H-2/H2O/Ni/SZ (SZ = stabilized zirconia) electrode kinetics have been presented in the literature in order to explain the reported experimental data. However, there has been a strong tendency of using a limited set of data to "verify" a given model, disregarding other data...... sets, which do not fit the model. We have inspected some models in the literature, and problems (e.g. no quantitative model has explained the large variation in reported values of apparent activation energy of the electrode kinetics) as well as strengths of the models are discussed. We point out...... important for any realistic and useful mathematical model of the H-2/H2O/Ni/SZ electrode....
4. Kinetics of oxidation of H2 and reduction of H2O in Ni-YSZ based solid oxide cells
DEFF Research Database (Denmark)
Ebbesen, Sune Dalgaard; Mogensen, Mogens Bjerg
2012-01-01
Reduction of H2O and oxidation of H2 was studied in a Ni-YSZ electrode supported Solid Oxide Cells produced at DTU Energy conversion (former Risø DTU). Polarisation (i-V) and electrochemical impedance spectroscopic characterisation show that the kinetics for reduction of H 2O is slower compared...... to oxidation of H2. The kinetic differences cannot be explained by the reaction mechanisms which are similar in the two cases but are rather an effect of the thermodynamics. The preliminary analysis performed in this study show that the slow kinetic for reduction is partly related to the endothermic nature...... of the reaction, cooling the active electrode, thereby leading to slower kinetics at low current densities. Likewise, the increased kinetic for oxidation was found to be related to the exothermic nature of the reaction, heating the active electrode, and thereby leading to faster kinetics. At higher current...
5. Different reaction of the core histones H2A and H2B to red laser irradiation
Science.gov (United States)
Brill, G. E.; Egorova, A. V.; Bugaeva, I. O.; Postnov, D. E.; Ushakova, O. V.
2017-03-01
Analysis of the influence of red laser irradiation on the processes of self-assembly of the core histones H2A and H2B was performed using a wedge dehydration method. Image-analysis of facies included their qualitative characteristics and calculation of quantitative parameters with subsequent statistical processing. It was established that linearly polarized red laser light (λ - 660 nm, 1 J/cm2) significantly modified the process of self-assembly of core histone H2B, whereas the structure of the facies of H2A histone changed to a lesser extent. Histones were used in the form of aqueous salt solutions. The effect of red light seems to result from the formation of singlet oxygen by direct laser excitation of molecular oxygen.
6. Crystal structure of strontium osmate (8) Sr[OsO5(H2O)]x3H2O
International Nuclear Information System (INIS)
Nevskij, N.N; Ivanov-Ehmin, B.N.; Nevskaya, N.A.; Belov, N.V.; AN SSSR, Moscow. Inst. Kristallografii)
1982-01-01
Crystal structure of the Sr[OsO 5 (H 2 O)]x3H 2 O complex is studied. Rhombic P-cell has the parameters: a=6.426(1), b=7.888(1), c=14.377(5) A, Vsub(c)=729 A 3 . The R-factor equals 0.034. The coordinates of the basis atoms and isotropic temperature corrections, as well as basic interatomic distances, are determined
7. Observations of interstellar H2O emission at 183 Gigahertz
International Nuclear Information System (INIS)
Waters, J.W.; Gustincic, J.J.; Kakar, R.K.; Kuiper, T.B.H.; Roscoe, H.K.; Swanson, P.N.; Rodriguez Kuiper, E.N.; Kerr, A.R.; Thaddeus, P.
1980-01-01
Line emission at 183 GHz by the 3 13 --2 20 rotational transition of water vapor has been detected from the Orion Nebula with the NASA Kuiper Airborne Observatory 91 cm telescope. The peak antenna temperature of the line is 15 K, its LSR velocity is 8 km s -1 , and its width is 15 km s -1 . The velocity profile has characteristics similar to those for CO:a narrow (approx.4 km s -1 ) ''spike'' centered at 9.5 km s -1 and a broad ''plateau'' with flaring wings centered at approx.8 km s -1 . Our 7'.5 antenna beam did not resolve the source. The 183 GHz H 2 O plateau emission appears enhanced above that expected for thermal excitation if it originates from the no greater than 1' region characteristic of plateau emission from all other observed molecules. The spike emission is consistent with an optically thick source of the approximated size of the well-known molecular ridge in Orion having the H 2 O in thermal equilibrium at Tapprox. =50 K. If this is the case, then the H 2 O column density giving rise to the spike is N/sub H/2/sub O/> or =3 x 10 17 cm -2 . An excitation calculation implies N/sub H/2/sub O/approx. =10 18 cm -2 for a source the size of the molecular ridge. These results imply that H 2 O is one of the more abundant species in the Orion Molecualr Cloud.H 2 O emission at 183 GHz was not detected in Sgr A, Sgr B2, W3, W43, W49, W51, DR 21, NGC 1333, NGC 7027, GL 2591, or the rho Oph cloud; it may have been detected in M17
8. HF/H2O2 treated graphite felt as the positive electrode for vanadium redox flow battery
Science.gov (United States)
He, Zhangxing; Jiang, Yingqiao; Meng, Wei; Jiang, Fengyun; Zhou, Huizhu; Li, Yuehua; Zhu, Jing; Wang, Ling; Dai, Lei
2017-11-01
In order to improve the electrochemical performance of the positive graphite felt electrode in vanadium flow redox battery, a novel method is developed to effectively modify the graphite felt by combination of etching of HF and oxidation of H2O2. After the etching of HF for the graphite felt at ambient temperature, abundant oxygen-containing functional groups were further introduced on the surface of graphite felt by hydrothermal treatment using H2O2 as oxidant. Benefiting from the surface etching and introduction of functional groups, mass transfer and electrode process can be improved significantly on the surface of graphite felt. VO2+/VO2+ redox reaction on the graphite felt modified by HF and H2O2 jointly (denote: GF-HF/H2O2) exhibits superior electrochemical kinetics in comparison with the graphite felt modified by single HF or H2O2 treatment. The cell using GF-HF/H2O2 as the positive electrode was assembled and its electrochemical properties were evaluated. The increase of energy efficiency of 4.1% for GF-HF/H2O2 at a current density of 50 mA cm-2 was obtained compared with the pristine graphite felt. The cell using GF-HF/H2O2 also demonstrated higher discharge capacity. Our study revealed that HF/H2O2 treatment is an efficient method to enhance the electrochemical performance of graphite felt, further improving the comprehensive energy storage performance of the vanadium flow redox battery.
9. Metagenomic Evidence for H2 Oxidation and H2 Production by Serpentinite-Hosted Subsurface Microbial Communities
Science.gov (United States)
Brazelton, William J.; Nelson, Bridget; Schrenk, Matthew O.
2012-01-01
Ultramafic rocks in the Earth’s mantle represent a tremendous reservoir of carbon and reducing power. Upon tectonic uplift and exposure to fluid flow, serpentinization of these materials generates copious energy, sustains abiogenic synthesis of organic molecules, and releases hydrogen gas (H2). In order to assess the potential for microbial H2 utilization fueled by serpentinization, we conducted metagenomic surveys of a marine serpentinite-hosted hydrothermal chimney (at the Lost City hydrothermal field) and two continental serpentinite-hosted alkaline seeps (at the Tablelands Ophiolite, Newfoundland). Novel [NiFe]-hydrogenase sequences were identified at both the marine and continental sites, and in both cases, phylogenetic analyses indicated aerobic, potentially autotrophic Betaproteobacteria belonging to order Burkholderiales as the most likely H2-oxidizers. Both sites also yielded metagenomic evidence for microbial H2 production catalyzed by [FeFe]-hydrogenases in anaerobic Gram-positive bacteria belonging to order Clostridiales. In addition, we present metagenomic evidence at both sites for aerobic carbon monoxide utilization and anaerobic carbon fixation via the Wood–Ljungdahl pathway. In general, our results point to H2-oxidizing Betaproteobacteria thriving in shallow, oxic–anoxic transition zones and the anaerobic Clostridia thriving in anoxic, deep subsurface habitats. These data demonstrate the feasibility of metagenomic investigations into novel subsurface habitats via surface-exposed seeps and indicate the potential for H2-powered primary production in serpentinite-hosted subsurface habitats. PMID:22232619
10. Metagenomic evidence for h(2) oxidation and h(2) production by serpentinite-hosted subsurface microbial communities.
Science.gov (United States)
Brazelton, William J; Nelson, Bridget; Schrenk, Matthew O
2012-01-01
Ultramafic rocks in the Earth's mantle represent a tremendous reservoir of carbon and reducing power. Upon tectonic uplift and exposure to fluid flow, serpentinization of these materials generates copious energy, sustains abiogenic synthesis of organic molecules, and releases hydrogen gas (H(2)). In order to assess the potential for microbial H(2) utilization fueled by serpentinization, we conducted metagenomic surveys of a marine serpentinite-hosted hydrothermal chimney (at the Lost City hydrothermal field) and two continental serpentinite-hosted alkaline seeps (at the Tablelands Ophiolite, Newfoundland). Novel [NiFe]-hydrogenase sequences were identified at both the marine and continental sites, and in both cases, phylogenetic analyses indicated aerobic, potentially autotrophic Betaproteobacteria belonging to order Burkholderiales as the most likely H(2)-oxidizers. Both sites also yielded metagenomic evidence for microbial H(2) production catalyzed by [FeFe]-hydrogenases in anaerobic Gram-positive bacteria belonging to order Clostridiales. In addition, we present metagenomic evidence at both sites for aerobic carbon monoxide utilization and anaerobic carbon fixation via the Wood-Ljungdahl pathway. In general, our results point to H(2)-oxidizing Betaproteobacteria thriving in shallow, oxic-anoxic transition zones and the anaerobic Clostridia thriving in anoxic, deep subsurface habitats. These data demonstrate the feasibility of metagenomic investigations into novel subsurface habitats via surface-exposed seeps and indicate the potential for H(2)-powered primary production in serpentinite-hosted subsurface habitats.
11. Metagenomic evidence for H2 oxidation and H2 production by serpentinite-hosted subsurface microbial communities
Directory of Open Access Journals (Sweden)
William J Brazelton
2012-01-01
Full Text Available Ultramafic rocks in the Earth’s mantle represent a tremendous reservoir of carbon and reducing power. Upon tectonic uplift and exposure to fluid flow, serpentinization of these materials generates copious energy, sustains abiogenic synthesis of organic molecules, and releases hydrogen gas (H2. In order to assess the potential for microbial H2 utilization fueled by serpentinization, we conducted metagenomic surveys of a marine serpentinite-hosted hydrothermal chimney (at the Lost City hydrothermal field and two continental serpentinite- hosted alkaline seeps (at the Tablelands Ophiolite, Newfoundland. Novel [NiFe]-hydrogenase sequences were identified at both the marine and continental sites, and in both cases, phylogenetic analyses indicated aerobic, potentially autotrophic Betaproteobacteria belonging to order Burkholderiales as the most likely H2-oxidizers. Both sites also yielded metagenomic evidence for microbial H2 production catalyzed by [FeFe]-hydrogenases in anaerobic Gram- positive bacteria belonging to order Clostridiales. In addition, we present metagenomic evidence at both sites for aerobic carbon monoxide utilization and anaerobic carbon fixation via the Wood-Ljungdahl pathway. In general, our results point to H2-oxidizing Betaproteobacteria thriving in shallow, oxic-anoxic transition zones and the anaerobic Clostridia thriving in anoxic, deep subsurface habitats. These data demonstrate the feasibility of metagenomic investigations into novel subsurface habitats via surface-exposed seeps and indicate the potential for H2- powered primary production in serpentinite-hosted subsurface habitats.
12. Different reaction of core histones H2A and H2B to the red laser radiation
Directory of Open Access Journals (Sweden)
Brill G.E.
2017-09-01
Full Text Available Aim: to investigate the influence of red laser irradiation on the processes of self-assembly of core histones H2A and H2B. Material and Methods. Solutions of human histone proteins were used in the work. Self-assembly was studied by the method of wedge dehydration. Image facies analysis consisted in their qualitative characterization and calculation of quantitative indicators with subsequent statistical processing. Results. It was established that linearly polarized laser light of the red region of the spectrum (A=660 nm, 1 J/cm2 significantly modifies the process of self-assembly of core histone H2B, while the structure of the facies of H2A histone changing to a lesser extent. Conclusion. Red laser radiation influences on the on the processes of self-assembly of core histones H2A and H2B. There is a differential sensitivity of different classes of histones to laser action. Histone proteins used in the experiments are present in the form of aqueous salt solutions. Red light realizes the effect seems to be due to the formation of singlet oxygen by direct laser excitation of molecular oxygen.
13. X-ray irradiation activates K+ channels via H2O2 signaling.
Science.gov (United States)
Gibhardt, Christine S; Roth, Bastian; Schroeder, Indra; Fuck, Sebastian; Becker, Patrick; Jakob, Burkhard; Fournier, Claudia; Moroni, Anna; Thiel, Gerhard
2015-09-09
Ionizing radiation is a universal tool in tumor therapy but may also cause secondary cancers or cell invasiveness. These negative side effects could be causally related to the human-intermediate-conductance Ca2+-activated-K+-channel (hIK), which is activated by X-ray irradiation and affects cell proliferation and migration. To analyze the signaling cascade downstream of ionizing radiation we use genetically encoded reporters for H2O2 (HyPer) and for the dominant redox-buffer glutathione (Grx1-roGFP2) to monitor with high spatial and temporal resolution, radiation-triggered excursions of H2O2 in A549 and HEK293 cells. The data show that challenging cells with ≥1 Gy X-rays or with UV-A laser micro-irradiation causes a rapid rise of H2O2 in the nucleus and in the cytosol. This rise, which is determined by the rate of H2O2 production and glutathione-buffering, is sufficient for triggering a signaling cascade that involves an elevation of cytosolic Ca2+ and eventually an activation of hIK channels.
14. Investigation of the Na2(H2PO2)2 - Ba(H2PO2)2 - H2O Water-Salt Ternary System at Room Temperature
OpenAIRE
Erge, Hasan; Turan, Hakan; Kul, Ali Riza
2016-01-01
Objective: In this study, the solubility, density, conductivity and phase equilibria of the Na2(H2PO2)2-Ba(H2PO2)2-H2O ternary system located in the structure of the Na+, Ba2+, (H2PO2)-//H2O quaternary reciprocal water-salt system were investigated using physicochemical analysis methods. Material and Methods: Riedel-de Haen and Merck salts were used to investigate the solubility and phase equilibria of the Na2(H2PO2)2 -Ba(H2PO2)2-H2O ternary water–salt system at room temperature Res...
15. H2O2 assisted room temperature oxidation of Ti2C MXene for Li-ion battery anodes
KAUST Repository
Ahmed, Bilal
2016-03-08
Herein we demonstrate that a prominent member of the MXene family, Ti2C, undergoes surface oxidation at room temperature when treated with hydrogen peroxide (H2O2). The H2O2 treatment results in opening up of MXene sheets and formation of TiO2 nanocrystals on their surface, which is evidenced by the high surface area of H2O2 treated MXene and X-ray diffraction (XRD) analysis. We show that the reaction time and the amount of hydrogen peroxide used are the limiting factors, which determine the morphology and composition of the final product. Furthermore, it is shown that the performance of H2O2 treated MXene as an anode material in Li ion batteries (LIBs) was significantly improved as compared to as-prepared MXenes. For instance, after 50 charge/discharge cycles, specific discharge capacities of 389 mA h g−1, 337 mA h g−1 and 297 mA h g−1 were obtained for H2O2 treated MXene at current densities of 100 mA g−1, 500 mA g−1 and 1000 mA g−1, respectively. In addition, when tested at a very high current density, such as 5000 mA g−1, the H2O2 treated MXene showed a specific capacity of 150 mA h g−1 and excellent rate capability. These results clearly demonstrate that H2O2 treatment of Ti2C MXene improves MXene properties in energy storage applications, such as Li ion batteries or capacitors.
16. H2O2 assisted room temperature oxidation of Ti2C MXene for Li-ion battery anodes
KAUST Repository
Ahmed, Bilal; Anjum, Dalaver H.; Hedhili, Mohamed N.; Gogotsi, Yury; Alshareef, Husam N.
2016-01-01
Herein we demonstrate that a prominent member of the MXene family, Ti2C, undergoes surface oxidation at room temperature when treated with hydrogen peroxide (H2O2). The H2O2 treatment results in opening up of MXene sheets and formation of TiO2 nanocrystals on their surface, which is evidenced by the high surface area of H2O2 treated MXene and X-ray diffraction (XRD) analysis. We show that the reaction time and the amount of hydrogen peroxide used are the limiting factors, which determine the morphology and composition of the final product. Furthermore, it is shown that the performance of H2O2 treated MXene as an anode material in Li ion batteries (LIBs) was significantly improved as compared to as-prepared MXenes. For instance, after 50 charge/discharge cycles, specific discharge capacities of 389 mA h g−1, 337 mA h g−1 and 297 mA h g−1 were obtained for H2O2 treated MXene at current densities of 100 mA g−1, 500 mA g−1 and 1000 mA g−1, respectively. In addition, when tested at a very high current density, such as 5000 mA g−1, the H2O2 treated MXene showed a specific capacity of 150 mA h g−1 and excellent rate capability. These results clearly demonstrate that H2O2 treatment of Ti2C MXene improves MXene properties in energy storage applications, such as Li ion batteries or capacitors.
17. Industrial production of MgH2 and its application
International Nuclear Information System (INIS)
Uesugi, H.; Sugiyama, T.; Nii, H.; Ito, T.; Nakatsugawa, I.
2011-01-01
Research highlights: → Tablet and powder Mg were hydrogenated in a 50 kg batch furnace based on thermal equilibrium method. → Compression of Mg tablet improved the hydrogenation yield. → Hydrolysis of MgH 2 using citric acid generated hydrogen under 373 K. → A MgH 2 -hydrogen reactor utilizing hydraulic head pressure was developed. → - Abstract: A process for the industrial production of magnesium hydride (MgH 2 ) based on a thermal equilibrium method and its application to portable hydrogen sources is proposed. Mg powders and tablets compressed with mechanically ground Mg ribbons were successfully hydrogenated in a 50-kg-batch furnace. The resultant MgH 2 showed a hydrogen yield of around 96% with good reproducibility. The compression ratio of Mg tablets was found to be an important factor in the hydrogenation yield. A hydrolysis technique using citric acid as an additive was employed to generate hydrogen under 373 K. Increasing the concentration of citric acid and the temperature accelerated the hydrolysis reactivity. A hydrogen reactor utilizing hydraulic head pressure was developed. It generated hydrogen continuously for 1 h at a flow rate of 100 ml min -1 with hydrolysis of 5 g of tablet-form MgH 2 . The conversion yield was around 70%, regardless of the flow rate.
18. Electrochemical, H2O2-Boosted Catalytic Oxidation System
Science.gov (United States)
Akse, James R.; Thompson, John O.; Schussel, Leonard J.
2004-01-01
An improved water-sterilizing aqueous-phase catalytic oxidation system (APCOS) is based partly on the electrochemical generation of hydrogen peroxide (H2O2). This H2O2-boosted system offers significant improvements over prior dissolved-oxygen water-sterilizing systems in the way in which it increases oxidation capabilities, supplies H2O2 when needed, reduces the total organic carbon (TOC) content of treated water to a low level, consumes less energy than prior systems do, reduces the risk of contamination, and costs less to operate. This system was developed as a variant of part of an improved waste-management subsystem of the life-support system of a spacecraft. Going beyond its original intended purpose, it offers the advantage of being able to produce H2O2 on demand for surface sterilization and/or decontamination: this is a major advantage inasmuch as the benign byproducts of this H2O2 system, unlike those of systems that utilize other chemical sterilants, place no additional burden of containment control on other spacecraft air- or water-reclamation systems.
19. Atmospheric photochemical loss of H and H2 from formaldehyde
DEFF Research Database (Denmark)
Simonsen, Jens Bæk; Rusteika, Nerijus; Johnson, Matthew Stanley
2008-01-01
We have performed ab initio calculations to examine the potential energy along the normal modes of ground-state HCHO and along the reaction coordinates for loss of H2 and atomic hydrogen, respectively. This exploration showed that there are no specific features that will lead to reaction on the e......We have performed ab initio calculations to examine the potential energy along the normal modes of ground-state HCHO and along the reaction coordinates for loss of H2 and atomic hydrogen, respectively. This exploration showed that there are no specific features that will lead to reaction...... on the excited-state surfaces for excitations that are relevant to the troposphere and stratosphere. The calculations did however lead to the localization of a conical intersection point through which a specific loss of H2 could take place. However, the conical intersection lies at 5.4 eV relative to the ground...
20. Data-Driven Controller Design The H2 Approach
CERN Document Server
Sanfelice Bazanella, Alexandre; Eckhard, Diego
2012-01-01
Data-driven methodologies have recently emerged as an important paradigm alternative to model-based controller design and several such methodologies are formulated as an H2 performance optimization. This book presents a comprehensive theoretical treatment of the H2 approach to data-driven control design. The fundamental properties implied by the H2 problem formulation are analyzed in detail, so that common features to all solutions are identified. Direct methods (VRFT) and iterative methods (IFT, DFT, CbT) are put under a common theoretical framework. The choice of the reference model, the experimental conditions, the optimization method to be used, and several other designer’s choices are crucial to the quality of the final outcome, and firm guidelines for all these choices are derived from the theoretical analysis presented. The practical application of the concepts in the book is illustrated with a large number of practical designs performed for different classes of processes: thermal, fluid processing a...
1. Electron runaway in rf discharges
International Nuclear Information System (INIS)
Chen, F.F.
1992-10-01
The critical electric field is computed as a function of pressure and starting energy for electrons to run away to high energies in moderate pressure discharges. The runaway conditions depend critically on the shape of the elastic cross section vs. energy curve. Computations are made for H, H 2 , and He gases, and it is shown that runaway occurs much more readily in atomic hydrogen than in the other gases. The values of the runaway fields are larger than would normally occur in dc discharges, where large voltages would lead to arc formation. However, in rf discharges such electric fields can be sustained over times long compared to electron transit times but short compared to ion transit times. (author)
2. Angioplasty and stent - heart - discharge
Science.gov (United States)
Drug-eluting stents - discharge; PCI - discharge; Percutaneous coronary intervention - discharge; Balloon angioplasty - discharge; Coronary angioplasty - discharge; Coronary artery angioplasty - discharge; Cardiac ...
3. Clinical Applications of CO2 and H2 Breath Test
Directory of Open Access Journals (Sweden)
ZHAO Si-qian;CHEN Bao-jun;LUO Zhi-fu
2016-08-01
Full Text Available Breath test is non-invasive, high sensitivity and high specificity. In this article, CO2 breath test, H2 breath test and their clinical applications were elaborated. The main applications of CO2 breath test include helicobacter pylori test, liver function detection, gastric emptying test, insulin resistance test, pancreatic exocrine secretion test, etc. H2 breath test can be applied in the diagnosis of lactose malabsorption and detecting small intestinal bacterial overgrowth. With further research, the breath test is expected to be applied in more diseases diagnosis.
4. Ultrafast Librational Relaxation of H2O in Liquid Water
DEFF Research Database (Denmark)
Petersen, Jakob; Møller, Klaus Braagaard; Rey, Rossend
2013-01-01
The ultrafast librational (hindered rotational) relaxation of a rotationally excited H2O molecule in pure liquid water is investigated by means of classical nonequilibrium molecular dynamics simulations and a power and work analysis. This analysis allows the mechanism of the energy transfer from...... the excited H2O to its water neighbors, which occurs on a sub-100 fs time scale, to be followed in molecular detail, i.e., to determine which water molecules receive the energy and in which degrees of freedom. It is found that the dominant energy flow is to the four hydrogen-bonded water partners in the first...
5. H∞ /H2 model reduction through dilated linear matrix inequalities
DEFF Research Database (Denmark)
Adegas, Fabiano Daher; Stoustrup, Jakob
2012-01-01
This paper presents sufficient dilated linear matrix inequalities (LMI) conditions to the $H_{infty}$ and $H_{2}$ model reduction problem. A special structure of the auxiliary (slack) variables allows the original model of order $n$ to be reduced to an order $r=n/s$ where $n,r,s in field{N}$. Arb......This paper presents sufficient dilated linear matrix inequalities (LMI) conditions to the $H_{infty}$ and $H_{2}$ model reduction problem. A special structure of the auxiliary (slack) variables allows the original model of order $n$ to be reduced to an order $r=n/s$ where $n,r,s in field... 6. Backward Stochastic H2/H∞ Control: Infinite Horizon Case Directory of Open Access Journals (Sweden) Zhen Wu 2014-01-01 Full Text Available The mixed H2/H∞ control problem is studied for systems governed by infinite horizon backward stochastic differential equations (BSDEs with exogenous disturbance signal. A necessary and sufficient condition for the existence of a unique solution to the H2/H∞ control problem is derived. The equivalent feedback solution is also discussed. Contrary to deterministic or stochastic forward case, the feedback solution is no longer feedback of the current state; rather, it is feedback of the entire history of the state. 7. H2 emission from Herbig-Haro objects International Nuclear Information System (INIS) Elias, J.H. 1980-01-01 Molecular hydrogen emission lines have been detected in six Herbig-Haro objects. The line intensities suggest tha the H 2 emission arises in a moderate-density, shock-heated gas, consistent with evidence for a similar origin of the visible emission-line spectra in Herbig-Haro objects. Indirect arguments indicate that the typical H 2 line widths are less than 70 km s -1 and that typical helicentric radial velocities are no more than 30 km s -1 in magnitude 8. [3H]-2-Deoxyglucose autoradiography in a molluscan nervous system International Nuclear Information System (INIS) Reingold, S.C.; Sejnowski, T.J.; Gelperin, A. 1981-01-01 The authors have used [ 3 H]2-deoxyglucose autoradiography to correlate the labeling of individual neurons with electrical activity within the central nervous system of a terrestrial mollusc, Limax maximus. In an electrically quiescent control preparation where a single neuron is impaled with a glass microelectrode but not stimulated, several somata are uniformly labeled at 3-5 times background. In preparations where a single cell is impaled and stimulated, one or more somata are heavily labeled with [ 3 H]2-deoxyglucose at 10-50 times tissue background. This technique may be useful for surveying metabolically active neurons during spontaneous and driven electrical activity. (Auth.) 9. Radiological discharges International Nuclear Information System (INIS) Woodliffe, J. 1990-01-01 Current practice of North Sea States on the discharge and disposal of liquid radioactive wastes to the North Sea are based on the declaration issued at the Second International Conference on the Protection of the North Sea, known as the London Declaration. This has three main points the first of which emphasises the application of the Best Available Technology to protect the North Sea, the second provides a framework on which future controls on radioactive discharges should be based. The third identifies two parts of the framework; to take into account the recommendations of international organizations and that any repositories of radioactive waste which are built should not pollute the North Sea. This chapter looks at how the concensus based on the London Declaration is working, gauges the progress made in the implementation of the policy goal, identifies existing and future areas for concern and proposes ways of strengthening the control of radioactive discharges. The emphasis is on the United Kingdom practice and regulations for liquid wastes, most of which comes from the Sellafield Reprocessing Plant. (author) 10. The solubility of gold in H 2 O-H 2 S vapour at elevated temperature and pressure Science.gov (United States) Zezin, Denis Yu.; Migdisov, Artashes A.; Williams-Jones, Anthony E. 2011-09-01 This experimental study sheds light on the complexation of gold in reduced sulphur-bearing vapour, specifically, in H 2O-H 2S gas mixtures. The solubility of gold was determined in experiments at temperatures of 300, 350 and 365 °C and reached 2.2, 6.6 and 6.3 μg/kg, respectively. The density of the vapour varied from 0.02 to 0.22 g/cm 3, the mole fraction of H 2S varied from 0.03 to 0.96, and the pressure in the cell reached 263 bar. Statistically significant correlations of the amount of gold dissolved in the fluid with the fugacity of H 2O and H 2S permit the experimental data to be fitted to a solvation/hydration model. According to this model, the solubility of gold in H 2O-H 2S gas mixtures is controlled by the formation of sulphide or bisulphide species solvated by H 2S or H 2O molecules. Formation of gold sulphide species is favoured statistically over gold bisulphide species and thus the gold is interpreted to dissolve according to reactions of the form: Au(s)+(n+1)HS(g)=AuS·(HS)n(g)+H(g) Au(s)+HS(g)+mHO(g)=AuS·(HO)m(g)+H(g) Equilibrium constants for Reaction (A1) and the corresponding solvation numbers ( K A1 and n) were evaluated from the study of Zezin et al. (2007). The equilibrium constants as well as the hydration numbers for Reaction (A2) ( K A2 and m) were adjusted simultaneously by a custom-designed optimization algorithm and were tested statistically. The resulting values of log K A2 and m are -15.3 and 2.3 at 300 and 350 °C and -15.1 and 2.2 at 365 °C, respectively. Using the calculated stoichiometry and stability of Reactions (A1) and (A2), it is now possible to quantitatively evaluate the contribution of reduced sulphur species to the transport of gold in aqueous vapour at temperatures up to 365 °C. This information will find application in modelling gold ore-forming processes in vapour-bearing magmatic hydrothermal systems, notably those of epithermal environments. 11. A study of the accelerated zircaloy-4 oxidation reaction with H2O/H2 mixture gas International Nuclear Information System (INIS) Kim, Y. S.; Cho, I. J. 2001-01-01 A study of the Zircaloy-4 reaction with H 2 O/H 2 mixture gas is carried out by using TGA (Thermo Gravimetric Apparatus) to estimate the hydrogen embrittlement which can possibly cause catastrophic nuclear fuel rod failure. Reaction rates are measured as a function of H 2 /H 2 O. In the experiments reaction temperature is set at 500 .deg. C and total pressure of the mixture gas is maintained at 1 atm. Experimental results reveal that hydriding and oxidation reaction are competing. In early stage, hydriding kinetics is faster than oxidation, however, oxidant in H 2 O forms oxide on the surface as steam environment is maintained, thus, this growing oxide begins to protect the zirconium base metal against hydrogen permeation. In this second stage, the total kinetic rate follows enhanced oxidation kinetics. In the final stage, it is observed that the oxide is broken down and massive hydriding takes place through the mechanical defects in the oxide, whose kinetics is similar to pure hydriding kinetics. These results are confirmed by SEM and EDX analysis along with hydrogen concentration measurements 12. OH density measured by PLIF in a nanosecond atmospheric pressure diffuse discharge in humid air under steep high voltage pulses Science.gov (United States) Ouaras, K.; Magne, L.; Pasquiers, S.; Tardiveau, P.; Jeanney, P.; Bournonville, B. 2018-04-01 The spatiotemporal distributions of the OH radical density are measured using planar laser induced fluorescence in the afterglow of a nanosecond diffuse discharge at atmospheric pressure in humid air. The diffuse discharge is generated between a pin and a grounded plate electrodes within a gap of 18 mm. The high voltage pulse applied to the pin ranges from 65 to 85 kV with a rise time of 2 ns. The specific electrical energy transferred to the gas ranges from 5 to 40 J l‑1. The influence of H2O concentration is studied from 0.5% to 1.5%. An absolute calibration of OH density is performed using a six-level transient rate equation model to simulate the dynamics of OH excitation by the laser, taking into account collisional processes during the optical pumping and the fluorescence. Rayleigh scattering measurements are used to achieve the geometrical part of the calibration. A local maximum of OH density is found in the pin area whatever the operating conditions. For 85 kV and 1% of H2O, this peak reaches a value of 2.0 × 1016 cm‑3 corresponding to 8% of H2O dissociation. The temporal decay of the spatially averaged OH density is found to be similar as in the afterglow of a homogeneous photo-triggered discharge for which a self-consistent modeling is done. These tools are then used to bring discussion elements on OH kinetics. 13. Adsorption of CO, CO2, H2, and H2O on titania surfaces with different oxidation states International Nuclear Information System (INIS) Raupp, G.B.; Dumesic, J.A. 1985-01-01 The adsorptive properties of titania surfaces with different oxidation states were proved by temperature-programmed desorption (TPD) of CO, H 2 , CO 2 , and H 2 O. Auger electron spectroscopy and X-ray photoelectron spectroscopy revealed that vacuum annealing an oxidized titanium foil at temperatures from 300 to 800 K was an effective means of systematically varying the average surface oxidation state from Ti 4+ to Ti 2+ . Carbon monoxide weakly adsorbed (desorption energy of 44-49 kJ x mol -1 ) in a carbonyl fashion on coordinatively unsaturated cation sites. Titania surfaces were inert with respect to H 2 adsorption and dissociation. Carbon dioxide adsorbed in a linear molecular fashion. Water adsorbed both molecularly and dissociatively. Results are discussed in terms of the role of titania oxidation state in CO hydrogenation over titania-supported metal catalysts. 74 references, 7 figures 14. A lysosome-locating and acidic pH-activatable fluorescent probe for visualizing endogenous H2O2 in lysosomes. Science.gov (United States) Liu, Jun; Zhou, Shunqing; Ren, Jing; Wu, Chuanliu; Zhao, Yibing 2017-11-20 There is increasing evidence indicating that lysosomal H 2 O 2 is closely related to autophagy and apoptotic pathways under both physiological and pathological conditions. Therefore, fluorescent probes that can be exploited to visualize H 2 O 2 in lysosomes are potential tools for exploring diverse roles of H 2 O 2 in cells. However, functional exploration of lysosomal H 2 O 2 is limited by the lack of fluorescent probes capable of compatibly sensing H 2 O 2 under weak acidic conditions (pH = 4.5) of lysosomes. Lower spatial resolution of the fluorescent visualization of lysosomal H 2 O 2 might be caused by the interference of signals from cytosolic and mitochondrial H 2 O 2 , as well as the non-specific distribution of the probes in cells. In this work, we developed a lysosome-locating and acidic-pH-activatable fluorescent probe for the detection and visualization of H 2 O 2 in lysosomes, which consists of a H 2 O 2 -responsive boronate unit, a lysosome-locating morpholine group, and a pH-activatable benzorhodol fluorophore. The response of the fluorescent probe to H 2 O 2 is significantly more pronounced under acidic pH conditions than that under neutral pH conditions. Notably, the present probe enables the fluorescence sensing of endogenous lysosomal H 2 O 2 in living cells without external stimulations, with signal interference from the cytoplasm and other intracellular organelles being negligible. 15. Solar kerosene from H2O and CO2 Science.gov (United States) Furler, P.; Marxer, D.; Scheffe, J.; Reinalda, D.; Geerlings, H.; Falter, C.; Batteiger, V.; Sizmann, A.; Steinfeld, A. 2017-06-01 The entire production chain for renewable kerosene obtained directly from sunlight, H2O, and CO2 is experimentally demonstrated. The key component of the production process is a high-temperature solar reactor containing a reticulated porous ceramic (RPC) structure made of ceria, which enables the splitting of H2O and CO2 via a 2-step thermochemical redox cycle. In the 1st reduction step, ceria is endo-thermally reduced using concentrated solar radiation as the energy source of process heat. In the 2nd oxidation step, nonstoichiometric ceria reacts with H2O and CO2 to form H2 and CO - syngas - which is finally converted into kerosene by the Fischer-Tropsch process. The RPC featured dual-scale porosity for enhanced heat and mass transfer: mm-size pores for volumetric radiation absorption during the reduction step and μm-size pores within its struts for fast kinetics during the oxidation step. We report on the engineering design of the solar reactor and the experimental demonstration of over 290 consecutive redox cycles for producing high-quality syngas suitable for the processing of liquid hydrocarbon fuels. 16. submitter Thermodynamics of the formation of sulfuric acid dimers in the binary (H2SO4–H2O) and ternary (H2SO4–H2O–NH3) system CERN Document Server Kürten, A; Rondo, L; Bianchi, F; Duplissy, J; Jokinen, T; Junninen, H; Sarnela, N; Schobesberger, S; Simon, M; Sipilä, M; Almeida, J; Amorim, A; Dommen, J; Donahue, N M; Dunne, E M; Flagan, R C; Franchin, A; Kirkby, J; Kupc, A; Makhmutov, V; Petäjä, T; Praplan, A P; Riccobono, F; Steiner, G; Tomé, A; Tsagkogeorgas, G; Wagner, P E; Wimmer, D; Baltensperger, U; Kulmala, M; Worsnop, D R; Curtius, J 2015-01-01 Sulfuric acid is an important gas influencing atmospheric new particle formation (NPF). Both the binary$(H_2SO_4–H_2O)$system and the ternary system involving ammonia$(H_2SO_4–H_2O–NH_3)$may be important in the free troposphere. An essential step in the nucleation of aerosol particles from gas-phase precursors is the formation of a dimer, so an understanding of the thermodynamics of dimer formation over a wide range of atmospheric conditions is essential to describe NPF. We have used the CLOUD chamber to conduct nucleation experiments for these systems at temperatures from 208 to 248 K. Neutral monomer and dimer concentrations of sulfuric acid were measured using a chemical ionization mass spectrometer (CIMS). From these measurements, dimer evaporation rates in the binary system were derived for temperatures of 208 and 223 K. We compare these results to literature data from a previous study that was conducted at higher temperatures but is in good agreement with the present study. For the ternary sys... 17. Room temperature CO and H2 sensing with carbon nanoparticles International Nuclear Information System (INIS) Kim, Daegyu; Pikhitsa, Peter V; Yang, Hongjoo; Choi, Mansoo 2011-01-01 We report on a shell-shaped carbon nanoparticle (SCNP)-based gas sensor that reversibly detects reducing gas molecules such as CO and H 2 at room temperature both in air and inert atmosphere. Crystalline SCNPs were synthesized by laser-assisted reactions in pure acetylene gas flow, chemically treated to obtain well-dispersed SCNPs and then patterned on a substrate by the ion-induced focusing method. Our chemically functionalized SCNP-based gas sensor works for low concentrations of CO and H 2 at room temperature even without Pd or Pt catalysts commonly used for splitting H 2 molecules into reactive H atoms, while metal oxide gas sensors and bare carbon-nanotube-based gas sensors for sensing CO and H 2 molecules can operate only at elevated temperatures. A pristine SCNP-based gas sensor was also examined to prove the role of functional groups formed on the surface of functionalized SCNPs. A pristine SCNP gas sensor showed no response to reducing gases at room temperature but a significant response at elevated temperature, indicating a different sensing mechanism from a chemically functionalized SCNP sensor. 18. Reaction of ferric leghemoglobin with H2O2 DEFF Research Database (Denmark) Moreau, S; Davies, M J; Puppo, A 1995-01-01 Ferric leghemoglobin in the presence of H2O2 is known to give rise to protein radicals, at least one of which is centred on a tyrosine residue. These radicals are quenched by at least two processes. The first one involves an intramolecular heme-protein cross-link probably involving the tyrosine r... 19. Analytical potential energy function for the Br + H2 system International Nuclear Information System (INIS) Kurosaki, Yuzuru 2001-01-01 Analytical functions with a many-body expansion for the ground and first-excited-state potential energy surfaces for the Br+H 2 system are newly presented in this work. These functions describe the abstraction and exchange reactions qualitatively well, although it has been found that the function for the ground-state potential surface is still quantitatively unsatisfactory. (author) 20. Surface tension of H2O and D2O International Nuclear Information System (INIS) Vargaftik, N.B.; Voljak, L.D.; Volkov, B.N. 1975-01-01 There is a great number of works on surface tension of clean water (H 2 O) at temperatures up to 100 deg C and very few above the boiling point. Works on surface tension of heavy water (D 2 O) are insufficient. A review of works on surface tension of both kinds of water is given 1. Review of H2 and O2 detection in LWRS International Nuclear Information System (INIS) Neidel, E.C.; Castle, J.G. Jr. 1981-01-01 Hydrogen detection systems are being installed in existing LWR's and are being planned for new ones. This review summarizes the present status of instrument availability and of application in nuclear power plants. The H 2 sensors in most of the detection systems purchased to date by the nuclear utilities are being located outside of containment. The air sampled for each H 2 sensor is circulated outside to the analyzer and back through two pipes which penetrate the containment wall. The travel time for the air to reach the sensor increases the response time for H 2 detection by approximately one-half minute. A few of the utilities will operate their H 2 sensors inside LWR containment. Since these systems lack radiation-hardened electronics, they require multiple wire penetrations which considerably increase installation costs and reduce the attractiveness of these systems. One electric power utility has requested quotations from hydrogen detector manufacturers for hydrogen detection equipment with better performance and faster system response than that presently available commercially. The requested detector response time of 15 seconds or less would permit the decision delay prior to initiating hydrogen control measures to be on the order of one minute 2. Inelastic scattering in metal-H-2-metal junctions DEFF Research Database (Denmark) Kristensen, I. S.; Paulsson, Magnus; Thygesen, Kristian Sommer 2009-01-01 We present first-principles calculations of the dI/dV characteristics of an H-2 molecule sandwiched between Au and Pt electrodes in the presence of electron-phonon interactions. The conductance is found to decrease by a few percentages at threshold voltages corresponding to the excitation energy ... 3. Dynamics of H2 on Ti/Al(100) surfaces NARCIS (Netherlands) Chen, Jian-Cheng 2011-01-01 What is the catalytic role played by titanium in the hydrogen storage material NaAlH4? This thesis aims at unraveling the dynamics of an elementary reaction: H2 dissociation on Ti/Al(100) surfaces. Although this reaction is not the rate limiting step in the hydrogen storage of NaAlH4, it is an 4. Economic analysis of novel synergistic biofuel (H2Bioil) processes International Nuclear Information System (INIS) Singh, Navneet R.; Mallapragada, Dharik S.; Agrawal, Rakesh; Tyner, Wallace E. 2012-01-01 Fast-pyrolysis based processes can be built on small-scale and have higher process carbon and energy efficiency as compared to other options. H 2 Bioil is a novel process based on biomass fast-hydropyrolysis and subsequent hydrodeoxygenation (HDO) and can potentially provide high yields of high energy density liquid fuel at relatively low hydrogen consumption. This paper contains a comprehensive financial analysis of the H 2 Bioil process with hydrogen derived from different sources. Three different carbon tax scenarios are analyzed: no carbon tax,$55/metric ton carbon tax and $110/metric ton carbon tax. The break-even crude oil price for a delivered biomass cost of$94/metric ton when hydrogen is derived from coal, natural gas or nuclear energy ranges from $103 to$116/bbl for no carbon tax and even lower ($99-$111/bbl) for the carbon tax scenarios. This break-even crude oil price compares favorably with the literature estimated prices of fuels from alternate biochemical and thermochemical routes. The impact of the chosen carbon tax is found to be limited relative to the impact of the H 2 source on the H 2 Bioil break-even price. The economic robustness of the processes for hydrogen derived from coal, natural gas, or nuclear energy is seen by an estimated break-even crude oil price of $114-$126/bbl when biomass cost is increased to \$121/metric ton. (orig.)
5. H2A Production Model, Version 2 User Guide
Energy Technology Data Exchange (ETDEWEB)
Steward, D.; Ramsden, T.; Zuboy, J.
2008-09-01
The H2A Production Model analyzes the technical and economic aspects of central and forecourt hydrogen production technologies. Using a standard discounted cash flow rate of return methodology, it determines the minimum hydrogen selling price, including a specified after-tax internal rate of return from the production technology. Users have the option of accepting default technology input values--such as capital costs, operating costs, and capacity factor--from established H2A production technology cases or entering custom values. Users can also modify the model's financial inputs. This new version of the H2A Production Model features enhanced usability and functionality. Input fields are consolidated and simplified. New capabilities include performing sensitivity analyses and scaling analyses to various plant sizes. This User Guide helps users already familiar with the basic tenets of H2A hydrogen production cost analysis get started using the new version of the model. It introduces the basic elements of the model then describes the function and use of each of its worksheets.
6. Glitters of warm H2 in cold diffuse molecular gas
NARCIS (Netherlands)
Falgarone, Edith; Beichman, Chaz; Boulanger, Francois; Combes, Francoise; Gry, Cecile; Helou, Georges; Laureijs, Rene; Pineau Des Forets, Guillaume; Valentijn, Edwin; Verstraete, Laurent
2004-01-01
Cold molecular hydrogen, a possibly dominant gas fraction in galaxies, does not radiate due to the symmetry and small moment of inertia of the molecule. The only tracers of cold H2, the rotational lines of CO and dust thermal emission operate only in metal-rich environments. By detecting the lowest
7. H2S-Mediated Thermal and Photochemical Methane Activation
NARCIS (Netherlands)
Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric V.
2013-01-01
Sustainable, low-temperature methods for natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) mixed with
8. Centrifugal turbocompressor with contactless sealing for H-2 S
International Nuclear Information System (INIS)
Peculea, M.; Balint, I.; Hirean, I.; Dumitrescu, C.; Pitigoi, Gh.; Balanuca, C.
1995-01-01
This paper reports the development of a centrifugal turbocompressor with contactless sealing for H 2 S specially designed for the ROMAG Drobeta heavy water plant. The bench-scale experiments are described and the resulted main characteristics are given. For this equipment an asymmetric automatic anti-pumping protection system has been developed and patented
9. Overtone vibrational spectroscopy in H2-H2O complexes: a combined high level theoretical ab initio, dynamical and experimental study.
Science.gov (United States)
Ziemkiewicz, Michael P; Pluetzer, Christian; Nesbitt, David J; Scribano, Yohann; Faure, Alexandre; van der Avoird, Ad
2012-08-28
First results are reported on overtone (v(OH) = 2 ← 0) spectroscopy of weakly bound H(2)-H(2)O complexes in a slit supersonic jet, based on a novel combination of (i) vibrationally mediated predissociation of H(2)-H(2)O, followed by (ii) UV photodissociation of the resulting H(2)O, and (iii) UV laser induced fluorescence on the nascent OH radical. In addition, intermolecular dynamical calculations are performed in full 5D on the recent ab initio intermolecular potential of Valiron et al. [J. Chem. Phys. 129, 134306 (2008)] in order to further elucidate the identity of the infrared transitions detected. Excellent agreement is achieved between experimental and theoretical spectral predictions for the most strongly bound van der Waals complex consisting of ortho (I = 1) H(2) and ortho (I = 1) H(2)O (oH(2)-oH(2)O). Specifically, two distinct bands are seen in the oH(2)-oH(2)O spectrum, corresponding to internal rotor states in the upper vibrational manifold of Σ and Π rotational character. However, none of the three other possible nuclear spin modifications (pH(2)-oH(2)O, pH(2)-pH(2)O, or oH(2)-pH(2)O) are observed above current signal to noise level, which for the pH(2) complexes is argued to arise from displacement by oH(2) in the expansion mixture to preferentially form the more strongly bound species. Direct measurement of oH(2)-oH(2)O vibrational predissociation in the time domain reveals lifetimes of 15(2) ns and <5(2) ns for the Σ and Π states, respectively. Theoretical calculations permit the results to be interpreted in terms of near resonant energy levels and intermolecular alignment of the H(2) and H(2)O wavefunctions, providing insight into predissociation dynamical pathways from these metastable levels.
10. Isotopic exchange processes in cold plasmas of H2/D2 mixtures.
Science.gov (United States)
Jiménez-Redondo, Miguel; Carrasco, Esther; Herrero, Víctor J; Tanarro, Isabel
2011-05-28
Isotope exchange in low pressure cold plasmas of H(2)/D(2) mixtures has been investigated by means of mass spectrometric measurements of neutrals and ions, and kinetic model calculations. The measurements, which include also electron temperatures and densities, were performed in a stainless steel hollow cathode reactor for three discharge pressures: 1, 2 and 8 Pa, and for mixture compositions ranging from 100% H(2) to 100% D(2). The data are analyzed in the light of the model calculations, which are in good global agreement with the experiments. Isotope selective effects are found both in the surface recombination and in the gas-phase ionic chemistry. The dissociation of the fuel gas molecules is followed by wall recycling, which regenerates H(2) and D(2) and produces HD. Atomic recombination at the wall is found to proceed through an Eley-Rideal mechanism, with a preference for reaction of the adsorbed atoms with gas phase D atoms. The best fit probabilities for Eley-Rideal abstraction with H and D are: γ(ER H) = 1.5 × 10(-3), γ(ER D) = 2.0 × 10(-3). Concerning ions, at 1 Pa the diatomic species H(2)(+), D(2)(+) and HD(+), formed directly by electron impact, prevail in the distributions, and at 8 Pa, the triatomic ions H(3)(+), H(2)D(+), HD(2)(+) and D(3)(+), produced primarily in reactions of diatomic ions with molecules, dominate the plasma composition. In this higher pressure regime, the formation of the mixed ions H(2)D(+) and HD(2)(+) is favoured in comparison with that of H(3)(+) and D(3)(+), as expected on statistical grounds. The model results predict a very small preference, undetectable within the precision of the measurements, for the generation of triatomic ions with a higher degree of deuteration, which is probably a residual influence at room temperature of the marked zero point energy effects (ZPE), relevant for deuterium fractionation in interstellar space. In contrast, ZPE effects are found to be decisive for the observed distribution of
11. Hydrogen Financial Analysis Scenario Tool (H2FAST); NREL (National Renewable Energy Laboratory)
Energy Technology Data Exchange (ETDEWEB)
Melaina, Marc
2015-04-21
This presentation describes the Hydrogen Financial Analysis Scenario Tool, H2FAST, and provides an overview of each of the three H2FAST formats: the H2FAST web tool, the H2FAST Excel spreadsheet, and the H2FAST Business Case Scenario (BCS) tool. Examples are presented to illustrate the types of questions that H2FAST can help answer.
12. Computational study on the mechanisms and energetics of trimethylindium reactions with H2O and H2S.
Science.gov (United States)
Raghunath, P; Lin, M C
2007-07-19
The reactions of trimethylindium (TMIn) with H2O and H2S are relevant to the chemical vapor deposition of indium oxide and indium sulfide thin films. The mechanisms and energetics of these reactions in the gas phase have been investigated by density functional theory and ab initio calculations using the CCSD(T)/[6-31G(d,p)+Lanl2dz]//B3LYP/[6-31G(d,p)+Lanl2dz] and CCSD(T)/[6-31G(d,p)+Lanl2dz] //MP2/[6-31G(d,p)+Lanl2dz] methods. The results of both methods are in good agreement for the optimized geometries and relative energies. When TMIn reacts with H2O and H2S, initial molecular complexes [(CH3)3In:OH2 (R1)] and [(CH3)3In:SH2 (R2)] are formed with 12.6 and 3.9 kcal/mol binding energies. Elimination of a CH4 molecule from each complex occurs with a similar energy barrier at TS1 (19.9 kcal/mol) and at TS3 (22.1 kcal/mol), respectively, giving stable intermediates (CH3)2InOH and (CH3)2InSH. The elimination of the second CH4 molecule from these intermediate products, however, has to overcome very high and much different barriers of 66.1 and 53.2 kcal/mol, respectively. In the case of DMIn with H2O and H2S reactions, formation of both InO and InS is exothermic by 3.1 and 30.8 kcal/mol respectively. On the basis of the predicted heats of formation of R1 and R2 at 0 K and -20.1 and 43.6 kcal/mol, the heats of formation of (CH3)2InOH, (CH3)2InSH, CH3InO, CH3InS, InO, and InS are estimated to be -20.6, 31.8, and 29.0 and 48.4, 35.5, and 58.5 kcal/mol, respectively. The values for InO and InS are in good agreement with available experimental data. A similar study on the reactions of (CH3)2In with H2O and H2S has been carried out; in these reactions CH3InOH and CH3InSH were found to be the key intermediate products.
13. Improved radiosensitive microcapsules using H2O2
International Nuclear Information System (INIS)
Harada, Satoshi; Ehara, Shigeru; Ishii, Keizo
2010-01-01
14. Tricyclic sesquiterpene copaene prevents H2O2-induced neurotoxicity
Directory of Open Access Journals (Sweden)
Hasan Turkez
2014-02-01
Full Text Available Aim: Copaene (COP, a tricyclic sesquiterpene, is present in several essential oils of medicinal and aromatic plants and has antioxidant and anticarcinogenic features. But, very little information is known about the effects of COP on oxidative stress induced neurotoxicity. Method: We used hydrogen peroxide (H2O2 exposure for 6 h to model oxidative stress. Therefore, this experimental design allowed us to explore the neuroprotective potential of COP in H2O2-induced toxicity in rat cerebral cortex cell cultures for the first time. For this purpose, methyl thiazolyl tetrazolium (MTT and lactate dehydrogenase (LDH release assays were carried out to evaluate cytotoxicity. Total antioxidant capacity (TAC and total oxidative stress (TOS parameters were used to evaluate oxidative changes. In addition to determining of 8-hydroxy-2-deoxyguanosine (8-OH-dG levels, the single cell gel electrophoresis (SCGE or comet assay was also performed for measuring the resistance of neuronal DNA to H2O2-induced challenge. Result: The results of this study showed that survival and TAC levels of the cells decreased, while TOS, 8-OH-dG levels and the mean values of the total scores of cells showing DNA damage increased in the H2O2 alone treated cultures. But pre-treatment of COP suppressed the cytotoxicity, genotoxicity and oxidative stress which were increased by H2O2. Conclusion: It is proposed that COP as a natural product with an antioxidant capacity in mitigating oxidative injuries in the field of neurodegenerative diseases. [J Intercult Ethnopharmacol 2014; 3(1.000: 21-28
15. H2 emission from non-stationary magnetized bow shocks
Science.gov (United States)
Tram, L. N.; Lesaffre, P.; Cabrit, S.; Gusdorf, A.; Nhung, P. T.
2018-01-01
When a fast moving star or a protostellar jet hits an interstellar cloud, the surrounding gas gets heated and illuminated: a bow shock is born that delineates the wake of the impact. In such a process, the new molecules that are formed and excited in the gas phase become accessible to observations. In this paper, we revisit models of H2 emission in these bow shocks. We approximate the bow shock by a statistical distribution of planar shocks computed with a magnetized shock model. We improve on previous works by considering arbitrary bow shapes, a finite irradiation field and by including the age effect of non-stationary C-type shocks on the excitation diagram and line profiles of H2. We also examine the dependence of the line profiles on the shock velocity and on the viewing angle: we suggest that spectrally resolved observations may greatly help to probe the dynamics inside the bow shock. For reasonable bow shapes, our analysis shows that low-velocity shocks largely contribute to H2 excitation diagram. This can result in an observational bias towards low velocities when planar shocks are used to interpret H2 emission from an unresolved bow. We also report a large magnetization bias when the velocity of the planar model is set independently. Our 3D models reproduce excitation diagrams in BHR 71 and Orion bow shocks better than previous 1D models. Our 3D model is also able to reproduce the shape and width of the broad H2 1-0S(1) line profile in an Orion bow shock (Brand et al. 1989).
16. Hysterectomy - vaginal - discharge
Science.gov (United States)
Vaginal hysterectomy - discharge; Laparoscopically assisted vaginal hysterectomy - discharge; LAVH - discharge ... you were in the hospital, you had a vaginal hysterectomy. Your surgeon made a cut in your ...
17. Information system for characterising emergency situations in H2O-H2S dual temperature isotopic exchange plants
International Nuclear Information System (INIS)
Croitoru, Cornelia; Anghel, Mihai; Pop, Floarea; Stefanescu, Ioan; Titescu, Gheorghe; Patrascu, Mihai; Watzlawek, Ervin; Cheresdi, Dorin
2006-01-01
Full text: In the frame of MENER project 'Information system for response in emergency situation', the National R and D Institute For Cryogenics And Isotopic Technologies - ICIT Rm. Valcea developed calculation programmes to characterise fourteen emergency situations. Emergency situations are presented when process fluids are discharged directly or not to environment. Release of hydrogen sulphide gas or water saturated with hydrogen sulphide into the water feed pipe, steam feed pipe, condense pipe, water distillation plant or waste treating plant represent emergency situations. The information system includes calculation programmes for process fluids break in automatic isolated enclosures, liquid, gas or liquefied gas discharge and atmospheric dispersion. The calculation programs allow including the human or not human intervention in starting the security systems (emergency stack, water inundation, liquid drainage). When the process fluids discharge directly to environment one presents on diagrams the discharge flow rates (local and/or stack), enclosure pressure and/or temperature and the atmospheric dispersion. When the process fluids discharge not directly to environment one presents on diagrams just the variation in time of local discharge flow. (authors)
18. Measurement of gas temperature and OH density in the afterglow of pulsed positive corona discharge
International Nuclear Information System (INIS)
Ono, Ryo; Oda, Tetsuji
2008-01-01
The gas temperature and OH density in the afterglow of pulsed positive corona discharge are measured using the laser-induced predissociation fluorescence (LIPF) of OH radicals. Discharge occurs in a 13 mm point-to-plane gap in an atmospheric-pressure H 2 O(2.8%)/O 2 (2.0%)/N 2 mixture. The temperature measurement shows that (i) the temperature increases after discharge and (ii) the temperature near the anode tip (within 1 mm from the anode tip) is much higher than that of the rest of the discharge volume. Near the anode tip, the temperature increases from 500 K (t = 0 μs) to 1100 K (t = 20 μs), where t is the postdischarge time, while it increases from 400 K (t = 0 μs) to 700 K (t = 100 μs) in the rest of the discharge volume away from the anode tip. This temperature difference between the two volumes (near and far from the anode tip) causes a difference in the decay rate of OH density: OH density near the anode tip decays approximately 10 times slower than that far from the tip. The spatial distribution of OH density shows good agreement with that of the secondary streamer luminous intensity. This shows that OH radicals are mainly produced in the secondary streamer, not in the primary one
19. Speciation in the aqueous H+/H2VO4-/H2O2/citrate system of biomedical interest.
Science.gov (United States)
Gorzsás, András; Getty, Kendra; Andersson, Ingegärd; Pettersson, Lage
2004-09-21
The speciation in the quaternary aqueous H+/H2VO4-/H2O2/citrate (Cit3-) and H+/H2VO4-/Cit3-/L-(+)-lactate (Lac-) systems has been determined at 25 degrees C in the physiological medium of 0.150 M Na(Cl). A combination of 51V NMR integral intensities and chemical shift (Bruker AMX500) as well as potentiometric data (glass electrode) have been collected and evaluated with the computer program LAKE, which is able to treat multimethod data simultaneously. The pKa-values for citric acid have been determined as 2.94, 4.34 and 5.61. Altogether six vanadate-citrate species have been found in the ternary H+/H2VO4-/Cit3- system in the pH region 2-10, only two of which are mononuclear. Reduction of vanadium(V) becomes more pronounced at pH acidic solutions limited the final model to pH > 4. In the quaternary H+/H2VO4-/Cit3-/Lac- system, two mixed-ligand species have been determined, with the compositions V2CitLac2- and V2CitLac3- (pKa = 5.0). To our knowledge, this is the first time such complexes have been reported for vanadium(V). 51V NMR chemical shifts, compositions and formation constants are given, and equilibrium conditions are illustrated in distribution diagrams as well as the fit of the model to the experimental data. When suitable, structural proposals are given, based on 13C NMR measurements and available literature data of related compounds.
20. Concentration of atomic hydrogen in a dielectric barrier discharge measured by two-photon absorption fluorescence
Science.gov (United States)
Dvořák, P.; Talába, M.; Obrusník, A.; Kratzer, J.; Dědina, J.
2017-08-01
Two-photon absorption laser-induced fluorescence (TALIF) was utilized for measuring the concentration of atomic hydrogen in a volume dielectric barrier discharge (DBD) ignited in mixtures of Ar, H2 and O2 at atmospheric pressure. The method was calibrated by TALIF of krypton diluted in argon at atmospheric pressure, proving that three-body collisions had a negligible effect on quenching of excited krypton atoms. The diagnostic study was complemented with a 3D numerical model of the gas flow and a zero-dimensional model of the chemistry in order to better understand the reaction kinetics and identify the key pathways leading to the production and destruction of atomic hydrogen. It was determined that the density of atomic hydrogen in Ar-H2 mixtures was in the order of 1021 m-3 and decreased when oxygen was added into the gas mixture. Spatially resolved measurements and simulations revealed a sharply bordered region with low atomic hydrogen concentration when oxygen was added to the gas mixture. At substoichiometric oxygen/hydrogen ratios, this H-poor region is confined to an area close to the gas inlet and it is shown that the size of this region is not only influenced by the chemistry but also by the gas flow patterns. Experimentally, it was observed that a decrease in H2 concentration in the feeding Ar-H2 mixture led to an increase in H production in the DBD.
1. Dissociation of nucleosomal particles by chemical modification. Equivalence of the two binding sites for H2A.H2B dimers
International Nuclear Information System (INIS)
Jordano, J.; Nieto, M.A.; Palacian, E.
1985-01-01
Treatment of nucleosomal particles with dimethylmaleic anhydride, a reagent for protein amino groups, is accompanied by a biphasic release of histones H2A plus H2B; one H2A.H2B dimer is more easily released than the other. This behavior allows the preparation of nucleosomal particles containing only one H2A.H2B dimer, which were complemented with 125 I-labeled H2A.H2B. These reconstituted particles, which contain one labeled and one unlabeled H2A.H2B dimer, were treated with the amount of reagent needed to release one of the two H2A.H2B dimers. Radioactivity was equally distributed between residual particles and released proteins, which is consistent with equivalent binding sites in the nucleosomal particle for H2A.H2B dimers, rather than with intrinsically different sites. The asymmetric release of H2A.H2B dimers would be caused by a change in the binding site of one dimer following the release of the other. This behavior might be related to the structural dynamics of nucleosomes
2. Co3(PO42·4H2O
Directory of Open Access Journals (Sweden)
Yang Kim
2008-10-01
Full Text Available Single crystals of Co3(PO42·4H2O, tricobalt(II bis[orthophosphate(V] tetrahydrate, were obtained under hydrothermal conditions. The title compound is isotypic with its zinc analogue Zn3(PO42·4H2O (mineral name hopeite and contains two independent Co2+ cations. One Co2+ cation exhibits a slightly distorted tetrahedral coordination, while the second, located on a mirror plane, has a distorted octahedral coordination environment. The tetrahedrally coordinated Co2+ is bonded to four O atoms of four PO43− anions, whereas the six-coordinate Co2+ is cis-bonded to two phosphate groups and to four O atoms of four water molecules (two of which are located on mirror planes, forming a framework structure. In addition, hydrogen bonds of the type O—H...O are present throughout the crystal structure.
3. Radiative association of CH3(+) and H2
International Nuclear Information System (INIS)
Bates, D.R.
1985-01-01
The temperature variation of the rate coefficient for k(1) for CH3(+) + H2 yields CH5(+) + hv is computed treating the para and ortho forms of H2 separately, taking account of nuclear spin and using an accurate theory of the kinetics of association. The results are made absolute with the aid of the measurement at 13 K by Barlow et al. (1984). By combining this measurement with the CH5(+) vibrational frequencies obtained by Pople (1984) from a quantal study, it is deduced that the probability of the stabilizing radiative transition is 5400/s. The rate coefficients k(1) (T, para) and k(1) (T, ortho) are given at 13 K, 30 K, and 80 K. 23 references
4. H2 as a Possible Carrier of the DIBs?
Science.gov (United States)
Ubachs, W.
2014-02-01
In the 1990s the hydrogen molecule, by far the most abundant molecular species in the interstellar medium, has been proposed as a possible carrier of the diffuse interstellar bands. While some remarkable coincidences were found in the rich spectrum of inter-Rydberg transitions of this molecule with DIB-features, both in frequency position as in linewidth, some open issues remained on a required non-linear optical pumping scheme that should explain the population of certain intermediate levels and act as a selection mechanism. Recently a similar scheme has been proposed relating the occurrence of the UV-bump (the ubiquitous 2170 Å extinction feature) to the spectrum of H2, therewith reviving the H2 hypothesis.
5. Spatial structure of radio frequency ring-shaped magnetized discharge sputtering plasma using two facing ZnO/Al2O3 cylindrical targets for Al-doped ZnO thin film preparation
Directory of Open Access Journals (Sweden)
Takashi Sumiyama
2017-05-01
Full Text Available Spatial structure of high-density radio frequency ring-shaped magnetized discharge plasma sputtering with two facing ZnO/Al2O3 cylindrical targets mounted in ring-shaped hollow cathode has been measured and Al-doped ZnO (AZO thin film is deposited without substrate heating. The plasma density has a peak at ring-shaped hollow trench near the cathode. The radial profile becomes uniform with increasing the distance from the target cathode. A low ion current flowing to the substrate of 0.19 mA/cm2 is attained. Large area AZO films with a resistivity of 4.1 – 6.7×10-4 Ω cm can be prepared at a substrate room temperature. The transmittance is 84.5 % in a visible region. The surface roughnesses of AZO films are 0.86, 0.68, 0.64, 1.7 nm at radial positions of r = 0, 15, 30, 40 mm, respectively, while diffraction peak of AZO films is 34.26°. The grains exhibit a preferential orientation along (002 axis.
6. VizieR Online Data Catalog: NGC253 near-infrared H2 emission (Rosenberg+,
Science.gov (United States)
Rosenberg, M. J. F.; van der Werf, P. P.; Israel, F. P.
2012-11-01
All observations were made with SINFONI at the ESO VLT. We observed in the H, and K bands using a spatial pixel scale of 0.25" corresponding to a field of view of 8" by 8" per frame and a spectral resolution of 2000, 3000 and 4000 respectively, which corresponds to a velocity resolution of 149.8, 99.9 and 74.9km/s. All science observations were taken in the ABA'nodding mode (300s of object, 300s of sky, 300s of object), where A' is slightly offset from A. The object exposures are aligned and averaged during the reconstruction of the data cube. The observations of NGC 253 were made in visitor mode on August 28th, 2005. In order to capture the full extent of the H2 emission, consecutive frames were taken in the K band moving further away from the center, along the disk until H2 was no longer detected. This resulted in 6 separate pointings. Since there are also H2 transitions in the H band, a similar strategy was used, resulting in 4 separate pointings. We used the standard reduction techniques of the SINFONI pipeline on all observations, including corrections for flat field, dark current, nonlinearity of pixels, distortion, and wavelength calibration. We obtained the flux calibration and atmospheric corrections from observations of a standard star, namely HR 2058 in the H band and HD 20001 in the K band (2 data files).
7. Quasimolecular autoionization in the collisions He+ - He, H2
International Nuclear Information System (INIS)
Ogurtsov, G.N.; Krupyshev, A.G.; Gordeev, Yu.S.
1993-01-01
Data on the autoionization transition level width dependence Γ(R) for He + - He, He + - H 2 pairs are obtained. Data on the probability of autoionization transition in a three-atom quasimolecule are obtained for the first time. It is shown that Γ(R) values for He + - He 2 quasimolecule exceed notably the similar values for isoelectron He + - He quasimolecule and may reach ∼ 1 eV. 6 refs., 2 figs
8. H 2 guaranteed cost control of discrete linear systems
Directory of Open Access Journals (Sweden)
Colmenares W.
2000-01-01
Full Text Available This paper presents necessary and sufficient conditions for the existence of a quadratically stabilizing output feedback controller which also assures H 2 guaranteed cost performance on a discrete linear uncertain system where the uncertainty is of the norm bounded type. The conditions are presented as a collection of linear matrix inequalities.The solution, however requires a search over a scalar parameter space.
9. Pb-H2O Thermogravimetric Plants. The Rankine Cycle
International Nuclear Information System (INIS)
Arosio, S.; Carlevaro, R.
2000-01-01
An economic evaluation concerning Pb-H 2 O thermogravimetric systems with an electric power in the range 200-1.000 kW has been done. Moreover, plant and running costs for a thermogravimetric and a Rankine cycle, 1 MW power, have been compared. Basically due to the lead charge, the plant cost of the former is higher: nevertheless such amount can be recuperated in less than three years, being higher the running cost of the latter [it
10. Membranes for H2 generation from nuclear powered thermochemical cycles
International Nuclear Information System (INIS)
Nenoff, Tina Maria; Ambrosini, Andrea; Garino, Terry J.; Gelbard, Fred; Leung, Kevin; Navrotsky, Alexandra; Iyer, Ratnasabapathy G.; Axness, Marlene
2006-01-01
In an effort to produce hydrogen without the unwanted greenhouse gas byproducts, high-temperature thermochemical cycles driven by heat from solar energy or next-generation nuclear power plants are being explored. The process being developed is the thermochemical production of Hydrogen. The Sulfur-Iodide (SI) cycle was deemed to be one of the most promising cycles to explore. The first step of the SI cycle involves the decomposition of H 2 SO 4 into O 2 , SO 2 , and H 2 O at temperatures around 850 C. In-situ removal of O 2 from this reaction pushes the equilibrium towards dissociation, thus increasing the overall efficiency of the decomposition reaction. A membrane is required for this oxygen separation step that is capable of withstanding the high temperatures and corrosive conditions inherent in this process. Mixed ionic-electronic perovskites and perovskite-related structures are potential materials for oxygen separation membranes owing to their robustness, ability to form dense ceramics, capacity to stabilize oxygen nonstoichiometry, and mixed ionic/electronic conductivity. Two oxide families with promising results were studied: the double-substituted perovskite A x Sr 1-x Co 1-y B y O 3-δ (A=La, Y; B=Cr-Ni), in particular the family La x Sr 1-x Co 1-y Mn y O 3-δ (LSCM), and doped La 2 Ni 1-x M x O 4 (M = Cu, Zn). Materials and membranes were synthesized by solid state methods and characterized by X-ray and neutron diffraction, SEM, thermal analyses, calorimetry and conductivity. Furthermore, we were able to leverage our program with a DOE/NE sponsored H 2 SO 4 decomposition reactor study (at Sandia), in which our membranes were tested in the actual H 2 SO 4 decomposition step
11. Non-adiabatic generator-coordinate calculation of H2+
International Nuclear Information System (INIS)
Tostes, J.G.R.; Para Univ., Belem; Toledo Piza, A.F.R. de
1982-10-01
A non-adiabatic calculation of the few lowest J=O states in the H 2+ molecule done within the framework of the Generator Coordinate Method is reported. Substantial accuracy is achivied with the diagonalization of matrices of very modest dimensions. The resulting wavefunctions are strongly dominated by just a few basis states. The computational scheme is set up so as to take the best advantage of good analytical approximations to existing adiabatic molecular wavefunctions. (Author) [pt
12. Periodic H-2 Synthesis for Spacecraft Attitude Control with Magnetometers
DEFF Research Database (Denmark)
Wisniewski, Rafal; Stoustrup, Jakob
2004-01-01
between the Earth´s magnetic field and an artificial magnetic field generated by the coils produces a control torque. The magnetic attitude control is intrinsically periodic due to cyclic variation of the geomagnetic field in orbit. The control performance is specified by the generalized H2 operator norm....... A linear matrix inequality-based algorithm is proposed for attitude control synthesis. Simulation results are provided, showing the prospect of the concept for onboard implementation....
13. Lung surgery - discharge
Science.gov (United States)
... Lung biopsy - discharge; Thoracoscopy - discharge; Video-assisted thoracoscopic surgery - discharge; VATS - discharge ... milk) for 2 weeks after video-assisted thoracoscopic surgery and 6 to 8 weeks after open surgery. ...
14. Pediatric heart surgery - discharge
Science.gov (United States)
... discharge; Heart valve surgery - children - discharge; Heart surgery - pediatric - discharge; Heart transplant - pediatric - discharge ... Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016:chap 434. ...
15. Determine the Intensity of UV Radiation and H2O2 on the Removal of Methylene Blue from Synthetic Wastewater
Directory of Open Access Journals (Sweden)
Mehdi Hosseini
2015-03-01
Full Text Available Background: There is a tremendous amount of color in textile wastewater that discharge it to the environment can cause a lot of environmental problems. The aim of this study is to evaluate the photocatalytic process UV/H2O2 to remove methylene blue dye from synthetic wastewater. Methods: UVC lamp was used as light source. In this study the effect of UV light intensity, irradiation distance, hydrogen peroxide concentration, and reaction time on the removal of methylene blue from aqueous solutions were studied. Data was analyzed by SPSS 18 and excel software. Results: The result showed that with increasing concentration of hydrogen peroxide, the color removal increases. Color removal changes were negligible at H2O2 concentration more than 5 mM. After 10 minutes reaction time at H2O2 concentration of 1 mm, efficiency of UVC/H2O2 is equal to 36.6%. Whilst at 5 mM concentration, removal efficiency is 89.2%. By increasing intensity of UV radiation, dye removal measure is also was increased, as the highest percentage of dye removal was obtained at 24 W radiation intensity. Conclusion: in present study, type of radiation and measure of hydrogen peroxide were the main factors in removal of methylene blue. Due to high efficiency of UVC/H2O2 process in removal of dye from aqueous solution, this method can use as an efficient process for removal of dye.
16. Hydrothermal synthesis, characterization, formation mechanism and electrochemical property of V3O7.H2O single-crystal nanobelts
International Nuclear Information System (INIS)
Zhang Yifu; Liu Xinghai; Xie Guangyong; Yu Lei; Yi Shengping; Hu Mingjie; Huang Chi
2010-01-01
Single-crystal V 3 O 7 .H 2 O nanobelts have been successfully synthesized in a large-scale by ethanol reducing of the commercial V 2 O 5 powder via a facile hydrothermal approach, without any templates and surfactants. The as-prepared V 3 O 7 .H 2 O nanobelts are up to several tens of micrometers in length, about 100 nm in width and about 20 nm in thickness in average, respectively. The 'Hydrating-Reducing-Exfoliating-Splitting' (HRES) mechanism was proposed to describe the formation of the V 3 O 7 .H 2 O nanobelts. In our research progress, it was found that the ratio of EtOH/H 2 O, the reaction time and categories of the reducing agents had significant effects on the morphology and composition of as-obtained products. Furthermore, the electrochemical properties of V 3 O 7 .H 2 O nanobelts were preformed and the results revealed that a lithium battery using those nanobelts as the positive electrode exhibited a high initial discharge capacity of 373 mAh/g.
17. Fast metastable hydrogen atoms from H2 molecules: twin atoms
Directory of Open Access Journals (Sweden)
Trimèche A.
2015-01-01
Full Text Available It is a difficult task to obtain “twin atoms”, i.e. pairs of massive particles such that one can perform experiments in the same fashion that is routinely done with “twin photons”. One possible route to obtain such pairs is by dissociating homonuclear diatomic molecules. We address this possibility by investigating the production of metastable H(2s atoms coming from the dissociation of cold H2 molecules produced in a Campargue nozzle beam crossing an electron beam from a high intensity pulsed electron gun. Dissociation by electron impact was chosen to avoid limitations of target molecular excited states due to selection rules. Detectors placed several centimeters away from the collision center, and aligned with respect to possible common molecular dissociation channel, analyze the neutral fragments as a function of their time-of-flight (TOF through Lyman-α detection. Evidence for the first time observed coincidence of pairs of H(2s atoms obtained this way is presented.
18. Graphene oxide and H2 production from bioelectrochemical graphite oxidation.
Science.gov (United States)
Lu, Lu; Zeng, Cuiping; Wang, Luda; Yin, Xiaobo; Jin, Song; Lu, Anhuai; Jason Ren, Zhiyong
2015-11-17
Graphene oxide (GO) is an emerging material for energy and environmental applications, but it has been primarily produced using chemical processes involving high energy consumption and hazardous chemicals. In this study, we reported a new bioelectrochemical method to produce GO from graphite under ambient conditions without chemical amendments, value-added organic compounds and high rate H2 were also produced. Compared with abiotic electrochemical electrolysis control, the microbial assisted graphite oxidation produced high rate of graphite oxide and graphene oxide (BEGO) sheets, CO2, and current at lower applied voltage. The resultant electrons are transferred to a biocathode, where H2 and organic compounds are produced by microbial reduction of protons and CO2, respectively, a process known as microbial electrosynthesis (MES). Pseudomonas is the dominant population on the anode, while abundant anaerobic solvent-producing bacteria Clostridium carboxidivorans is likely responsible for electrosynthesis on the cathode. Oxygen production through water electrolysis was not detected on the anode due to the presence of facultative and aerobic bacteria as O2 sinkers. This new method provides a sustainable route for producing graphene materials and renewable H2 at low cost, and it may stimulate a new area of research in MES.
19. Intermolecular Interactions in Ternary Glycerol–Sample–H2O
DEFF Research Database (Denmark)
Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata
2011-01-01
We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...... little effect on HGly-GlyEHEGly--Gly. This contrasts with our earlier studies on 1P–S–H2O in that Na+, F− and Cl− are found as hydration centers from the induced changes on HIP-IPEHEIP--IP in the presence of S, while Br−, I−, and SCN− are found to act as hydrophiles. In comparison with the Hofmeister...... ranking of these ions, the kosmotropes are hydration centers and the more kosmotropic the higher the hydration number, consistent with the original Hofmeister’s concept of “H2O withdrawing power.” Br−, I− and SCN−, on the other hand, acted as hydrophiles and the more chaotropic they are the more...
20. A SIFT study of the reactions of H2ONO+ ions with several types of organic molecules
Science.gov (United States)
Smith, David; Wang, Tianshu; Spanel, Patrik
2003-11-01
A selected ion flow tube (SIFT) study has been carried out of the reactions of hydrated nitrosonium ions, NO+H2O, which theory has equated to protonated nitrous acid ions, H2ONO+. One objective of this study was to investigate if this ion exhibits the properties of both a cluster ion and a protonated acid in their reactions with a variety of organic molecules. The chosen reactant molecules comprise two each of the following types--amines, terpenes, aromatic hydrocarbons, esters, carboxylic acids, ketones, aldehydes and alcohols. The reactant H2ONO+ (NO+H2O) ions are formed in a discharge ion source and injected into helium carrier gas where they are partially vibrationally excited and partially dissociated to NO+ ions. Hence, the reactions of the H2ONO+ ions had to be studies simultaneously with NO+ ions, the reactions of the latter ions readily being studied by selectively injecting NO+ ions into the carrier gas. The results of this study indicate that the H2ONO+ ions undergo a wide variety of reaction processes that depend on the properties of the reactant molecules such as their ionisation energies and proton affinities. These processes include charge transfer with compounds, M, that have low ionisation energies (producing M+), proton transfer with compounds possessing large proton affinities (MH+), hydride ion transfer (M---H+), alkyl radical (M---R+), alkoxide radical transfer (M---OR+), ion-molecule association (NO+H2OM) and ligand switching (NO+M), producing the ions given in parentheses.
1. Ortho-H2 and the age of prestellar cores
Science.gov (United States)
Pagani, L.; Lesaffre, P.; Jorfi, M.; Honvault, P.; González-Lezana, T.; Faure, A.
2013-03-01
Prestellar cores form from the contraction of cold gas and dust material in dark clouds before they collapse to form protostars. Several concurrent theories exist to describe this contraction but they are currently difficult to distinguish. One major difference is the timescale involved in forming the prestellar cores: some theories advocate nearly free-fall speed via, e.g., rapid turbulence decay, while others can accommodate much longer periods to let the gas accumulate via, e.g., ambipolar diffusion. To tell the difference between these theories, measuring the age of prestellar cores could greatly help. However, no reliable clock currently exists. We present a simple chemical clock based on the regulation of the deuteration by the abundance of ortho-H2 that slowly decays away from the ortho-para statistical ratio of 3 down to or less than 0.001. We use a chemical network fully coupled to a hydrodynamical model that follows the contraction of a cloud, starting from uniform density, and reaches a density profile typical of a prestellar core. We compute the N2D+/N2H+ ratio along the density profile. The disappearance of ortho-H2 is tied to the duration of the contraction and the N2D+/N2H+ ratio increases in the wake of the ortho-H2 abundance decrease. By adjusting the time of contraction, we obtain different deuteration profiles that we can compare to the observations. Our model can test fast contractions (from 104 to 106 cm-3 in ~0.5 My) and slow contractions (from 104 to 106 cm-3 in ~5 My). We have tested the sensitivity of the models to various initial conditions. The slow-contraction deuteration profile is approximately insensitive to these variations, while the fast-contraction deuteration profile shows significant variations. We found that, in all cases, the deuteration profile remains clearly distinguishable whether it comes from the fast collapse or the slow collapse. We also study the para-D2H+/ortho-H2D+ ratio and find that its variation is not monotonic
2. Partial discharges and bulk dielectric field enhancement
DEFF Research Database (Denmark)
McAllister, Iain Wilson; Johansson, Torben
2000-01-01
A consequence of partial discharge activity within a gaseous void is the production of a field enhancement in the solid dielectric in the proximity of the void. This situation arises due to the charge created by the partial discharges accumulating at the void wall. The influence of the spatial...
3. Effects of H2O and H2O2 on thermal desorption of tritium from stainless steel
International Nuclear Information System (INIS)
Quinlan, M. J.; Shmayda, W. T.; Lim, S.; Salnikov, S.; Chambers, Z.; Pollock, E.; Schroeder, W. U.
2008-01-01
Tritiated stainless steel was subjected to thermal desorption at various temperatures, different temperature profiles, and in the presence of different helium carrier gas additives. In all cases the identities of the desorbing tritiated species were characterized as either water-soluble or insoluble. The samples were found to contain 1.1 mCi±0.4 mCi. Approximately ninety-five percent of this activity was released in molecular water-soluble form. Additives of H 2 O or H 2 O 2 to dry helium carrier gas increase the desorption rate and lower the maximum temperature to which the sample must be heated, in order to remove the bulk of the tritium. The measurements validate a method of decontamination of tritiated steel and suggest a technique that can be used to further explore the mechanisms of desorption from tritiated metals. (authors)
4. Mesospheric H2O and H2O2 densities inferred from in situ positive ion composition measurement
Science.gov (United States)
Kopp, E.
1984-01-01
A model for production and loss of oxonium ions in the high-latitude D-region is developed, based on the observed excess of 34(+) which has been interpreted as H2O2(+). The loss mechanism suggested in the study is the attachment of N2 and/or CO2 in three-body reactions. Furthermore, mesospheric water vapor and H2O2 densities are inferred from measurements of four high-latitude ion compositions, based on the oxonium model. Mixing ratios of hydrogen peroxide of up to two orders of magnitude higher than previous values were obtained. A number of reactions, reaction constants, and a block diagram of the oxonium ion chemistry in the D-region are given.
5. Rotational excitation of H2O by para-H2 from an adiabatically reduced dimensional potential.
Science.gov (United States)
Scribano, Yohann; Faure, Alexandre; Lauvergnat, David
2012-03-07
Cross sections and rate coefficients for low lying rotational transitions in H(2)O colliding with para-hydrogen pH(2) are computed using an adiabatic approximation which reduces the dimensional dynamics from a 5D to a 3D problem. Calculations have been performed at the close-coupling level using the recent potential of Valiron et al. [J. Chem. Phys. 129, 134306 (2008)]. A good agreement is found between the reduced adiabatic calculations and the 5D exact calculations, with an impressive time saving and memory gain. This adiabatic reduction of dimensionality seems very promising for scattering studies involving the excitation of a heavy target molecule by a light molecular projectile. © 2012 American Institute of Physics
6. Retention and variability of hydrogen (H2) samples stored in plastic syringes
DEFF Research Database (Denmark)
Rumessen, J J; Gudmand-Høyer, E
1987-01-01
The utility of two brands of 20 ml plastic syringes for storage of hydrogen (H2) samples as obtained in H2 breath tests were studied. Plastipak syringes were found to be significantly better with regard to the stability of the H2 concentration and the variability between the H2 samples. Storage...... of the H2 samples in Plastipak syringes at 5 degrees C significantly improved the H2 retention, whereas refrigeration of H2 samples stored in Once syringes did not reduce H2 loss. Storage of H2 samples in refrigerated plastic syringes is efficient and reliable for several days if syringes with minimal...... sample variation are used....
7. Capture and dissociation in the complex-forming CH + H2 → CH2 + H, CH + H2 reactions.
Science.gov (United States)
González, Miguel; Saracibar, Amaia; Garcia, Ernesto
2011-02-28
The rate coefficients for the capture process CH + H(2)→ CH(3) and the reactions CH + H(2)→ CH(2) + H (abstraction), CH + H(2) (exchange) have been calculated in the 200-800 K temperature range, using the quasiclassical trajectory (QCT) method and the most recent global potential energy surface. The reactions, which are of interest in combustion and in astrochemistry, proceed via the formation of long-lived CH(3) collision complexes, and the three H atoms become equivalent. QCT rate coefficients for capture are in quite good agreement with experiments. However, an important zero point energy (ZPE) leakage problem occurs in the QCT calculations for the abstraction, exchange and inelastic exit channels. To account for this issue, a pragmatic but accurate approach has been applied, leading to a good agreement with experimental abstraction rate coefficients. Exchange rate coefficients have also been calculated using this approach. Finally, calculations employing QCT capture/phase space theory (PST) models have been carried out, leading to similar values for the abstraction rate coefficients as the QCT and previous quantum mechanical capture/PST methods. This suggests that QCT capture/PST models are a good alternative to the QCT method for this and similar systems.
8. Time resolved LIF measurements for the study of NO removal: influence of H2O
International Nuclear Information System (INIS)
Fresnet, F.; Baravian, G.; Magne, L.; Pasquiers, S.; Postel, C.; Puech, V.; Rousseau, A.
2001-01-01
We have developed a time-resolved laser-induced fluorescence (LIF) diagnostic of the NO-removal in a pre-ionized homogeneous discharge, i.e. without density nor temperature gradients, using the photo-triggering technique. This technique allows to measure specie densities in the temporal post-discharge after one homogeneous pulsed excitation, so that experimental results can be more confidently compared to predictions of a 0D-model, i.e. a model which have a spatially homogeneous kinetic description of the cleaning process. This model is fully self-consistent and describe both kinetics during the discharge and the post-discharge. We first reported the influence of electrical parameters (energy and reduced electric field) on the NO removal efficiency in the N 2 /NO mixture. Then, the influence of hydrocarbon (C 2 H 4 ) addition was determined. We showed that dissociation of NO through collision with the metastable state N 2 (a '1 Σ u - ) play the main part in the NO-removal process in homogeneously excited N 2 /NO mixture, and, that a de-excitation process of N 2 (a '1 Σ u - ) by C 2 H 4 explains that the NO-removal efficiency decreases when ethene is added to the mixture. Estimation for the rate coefficient value of this reaction, closed to the known value for methane, was also deduced from our results. In this study, the influence of water is investigated on the NO removal efficiency
9. Relationship between C2H2 reduction, H2 evolution and 15N2 fixation in root nodules of pea (Pisum sativum)
DEFF Research Database (Denmark)
Skøt, Leif
1983-01-01
for N2 reduction, is often stated as the relative efficiency (1-H2/C2H2). This factor varied significantly (P 2 and N2, expressed as the H2/N2 ratio, was independent of plant age, however. This discrepancy and the observation......The quantitative relationship between C2H2 reduction, H2 evolution and 15N2 fixation was investigated in excised root nodules from pea plants (Pisum sativum L. cv. Bodil) grown under controlled conditions. The C2H2/N2 conversion factor varied from 3.31 to 5.12 between the 32nd and the 67th day...... after planting. After correction for H2 evolution in air, the factor (C2H2-H2)/N2 decreased to values near the theoretical value 3, or in one case to a value significantly (P 2 production but used...
10. Ultrafast phosphate hydration dynamics in bulk H2O
International Nuclear Information System (INIS)
Costard, Rene; Tyborski, Tobias; Fingerhut, Benjamin P.; Elsaesser, Thomas
2015-01-01
Phosphate vibrations serve as local probes of hydrogen bonding and structural fluctuations of hydration shells around ions. Interactions of H 2 PO 4 − ions and their aqueous environment are studied combining femtosecond 2D infrared spectroscopy, ab-initio calculations, and hybrid quantum-classical molecular dynamics (MD) simulations. Two-dimensional infrared spectra of the symmetric (ν S (PO 2 − )) and asymmetric (ν AS (PO 2 − )) PO 2 − stretching vibrations display nearly homogeneous lineshapes and pronounced anharmonic couplings between the two modes and with the δ(P-(OH) 2 ) bending modes. The frequency-time correlation function derived from the 2D spectra consists of a predominant 50 fs decay and a weak constant component accounting for a residual inhomogeneous broadening. MD simulations show that the fluctuating electric field of the aqueous environment induces strong fluctuations of the ν S (PO 2 − ) and ν AS (PO 2 − ) transition frequencies with larger frequency excursions for ν AS (PO 2 − ). The calculated frequency-time correlation function is in good agreement with the experiment. The ν(PO 2 − ) frequencies are mainly determined by polarization contributions induced by electrostatic phosphate-water interactions. H 2 PO 4 − /H 2 O cluster calculations reveal substantial frequency shifts and mode mixing with increasing hydration. Predicted phosphate-water hydrogen bond (HB) lifetimes have values on the order of 10 ps, substantially longer than water-water HB lifetimes. The ultrafast phosphate-water interactions observed here are in marked contrast to hydration dynamics of phospholipids where a quasi-static inhomogeneous broadening of phosphate vibrations suggests minor structural fluctuations of interfacial water
11. Ultrafast phosphate hydration dynamics in bulk H2O
Science.gov (United States)
Costard, Rene; Tyborski, Tobias; Fingerhut, Benjamin P.; Elsaesser, Thomas
2015-06-01
Phosphate vibrations serve as local probes of hydrogen bonding and structural fluctuations of hydration shells around ions. Interactions of H2PO4- ions and their aqueous environment are studied combining femtosecond 2D infrared spectroscopy, ab-initio calculations, and hybrid quantum-classical molecular dynamics (MD) simulations. Two-dimensional infrared spectra of the symmetric ( ν S ( PO2 - ) ) and asymmetric ( ν A S ( PO2 - ) ) PO 2- stretching vibrations display nearly homogeneous lineshapes and pronounced anharmonic couplings between the two modes and with the δ(P-(OH)2) bending modes. The frequency-time correlation function derived from the 2D spectra consists of a predominant 50 fs decay and a weak constant component accounting for a residual inhomogeneous broadening. MD simulations show that the fluctuating electric field of the aqueous environment induces strong fluctuations of the ν S ( PO2 - ) and ν A S ( PO2 - ) transition frequencies with larger frequency excursions for ν A S ( PO2 - ) . The calculated frequency-time correlation function is in good agreement with the experiment. The ν ( PO2 - ) frequencies are mainly determined by polarization contributions induced by electrostatic phosphate-water interactions. H2PO4-/H2O cluster calculations reveal substantial frequency shifts and mode mixing with increasing hydration. Predicted phosphate-water hydrogen bond (HB) lifetimes have values on the order of 10 ps, substantially longer than water-water HB lifetimes. The ultrafast phosphate-water interactions observed here are in marked contrast to hydration dynamics of phospholipids where a quasi-static inhomogeneous broadening of phosphate vibrations suggests minor structural fluctuations of interfacial water.
12. A new vibrational level of the H2+ molecular ion
International Nuclear Information System (INIS)
Carbonell, J.; Lazauskas, R.; Delande, D.; Hilico, L.; Kilic, S.; Hilico, L.; Kilic, S.
2003-01-01
A new vibrational level of the molecular ion H 2 + with binding energy of 1.09 x 10 -9 a.u. ∼ 30 neV below the first dissociation limit is predicted, using highly accurate numerical non-relativistic quantum calculations, which go beyond the Born-Oppenheimer approximation. It is the first-excited vibrational level v=1 of the 2pσ u electronic state, antisymmetric with respect to the exchange of the two protons, with orbital angular momentum L=0. It manifests itself as a huge p - H scattering length of a = 750 ± 5 Bohr radii. (authors)
13. H2O maser flare in Orion A
International Nuclear Information System (INIS)
Matveenko, L.I.; Moran, J.M.; Genzel, R.
1982-01-01
The flare of H 2 O maser emission in Orion A was observed with the Crimea--Effelsberg and Haystack--Green Bank interferometers in November 1979. Its position is α = 5/sup h/32/sup m/46/sup s/.6 +- 0/sup s/.06, delta = -5 0 24'.28''.7 +- 1'' (1950.0); its radial velocity, 8 km/sec. The asymmetric line profile has a 28-kHz halfwidth. The flare source comprises a 0''.0005 core (T/sub b/ = 5 x 10 16 0 K) embedded in a 0''.005 halo (T/sub b/ = 3 x 10 14 0 K)
14. An application to H2+ of Laplace type integral transform
International Nuclear Information System (INIS)
Primorac, M.; Kovacevic, K.
1985-01-01
Laplace type integral transformation (LIT) has been applied to wavefunctions. The effect of the inverse transform is also discussed. LIT wavefunctions are tested in the calculation of the ground-state energy of H 2 + , where the untransformed functions were 1s, 12s, 123s and 1234s-STO. The results presented here show that LIT wavefunctions are applicable in molecular computations. The analytical formulae for two-centre one-electron integrals over LIT wavefunctions are derived by use of a Barnett-Coulson-like expansion of rsub(b)sup(N)(rsub(b)+p)sup(-ν). (orig.)
15. Hydrogen Learning for Local Leaders – H2L3
Energy Technology Data Exchange (ETDEWEB)
Serfass, Patrick [Technology Transition Corporation, Washington, DC (United States)
2017-03-30
The Hydrogen Learning for Local Leaders program, H2L3, elevates the knowledge about hydrogen by local government officials across the United States. The program reaches local leaders directly through “Hydrogen 101” workshops and webinar sessions; the creation and dissemination of a unique report on the hydrogen and fuel cell market in the US, covering 57 different sectors; and support of the Hydrogen Student Design Contest, a competition for interdisciplinary teams of university students to design hydrogen and fuel cell systems based on technology that’s currently commercially available.
16. Testing of irradiated and annealed 15H2MFA materials
International Nuclear Information System (INIS)
Gillemot, F.; Uri, G.
1994-01-01
A set of surveillance samples made from 15H2MFA material has been studied in the laboratory of AEKI. Miniature notched tensile specimens were cut from some remnants of irradiated and broke surveillance charpy remnants. The Absorbed Specific Fracture Energy (ASFE) was measured on the specimens. A cutting machine and testing technique were elaborated for the measurements. The second part of the Charpy remnants was annealed at 460 deg. C and 490 deg. C for 6-8 hours. The specimens were tested similarity and the results were compared. (author). 5 refs, 9 figs
17. Gene-specific characterization of human histone H2B by electron capture dissociation.
Science.gov (United States)
Siuti, Nertila; Roth, Michael J; Mizzen, Craig A; Kelleher, Neil L; Pesavento, James J
2006-02-01
The basis set of protein forms expressed by human cells from the H2B gene family was determined by Top Down Mass Spectrometry. Using Electron Capture Dissociation for MS/MS of H2B isoforms, direct evidence for the expression of unmodified H2B.Q, H2B.A, H2B.K/T, H2B.J, H2B.E, H2B.B, H2B.F, and monoacetylated H2B.A was obtained from asynchronous HeLa cells. H2B.A was the most abundant form, with the overall expression profile not changing significantly in cells arrested in mitosis by colchicine or during mid-S, mid-G2, G2/M, and mid-G1 phases of the cell cycle. Modest hyperacetylation of H2B family members was observed after sodium butyrate treatment.
18. Structure of solid H2-D2 mixtures
International Nuclear Information System (INIS)
Krupskij, I.N.; Kovalenko, S.I.; Krajnyukova, N.V.
1978-01-01
The structure of vapor deposited H 2 -D 2 solid mixtures is investigated. The electron-diffraction examination has been carried out in the temperature range from 2.3K up to the sample sublimation temperature, taking place in case of H 2 at T approximately 5K and D 2 -at T approximately 7K. On the basis of the difractogramm obtained it is shown that in solid films of pure components a FCC structure with parameters asub(Hsub(2))=5.310+-0.01A and asub(Osub(2))=5.100+-0.005A is realized, the structure being metastable in the temperature range. The existence of non-limitted solubility in solid two-component condensates is stated. The decay absence at T approximately 5K, when molecula mobility is enough for the transition of metastable FCC structure into HCP, is in good agreement with the results of experimental and theoretical estimations, according to which the decay critical temperature should not exceed 4K. The existance of the continuous series of solutions at lower temperatures is explained by a small coefficient value of a volumetric and surface diffusion of molecula as well
19. Structure and stability of solid Xe(H2)n
International Nuclear Information System (INIS)
Somayazulu, Maddury; Hemley, Russell J.; Dera, Przemyslaw; Smith, Jesse
2015-01-01
Mixtures of xenon and molecular hydrogen form a series of hexagonal, van der Waals compounds at high pressures and at 300 K. Synchrotron, x-ray, single crystal diffraction studies reveal that below 7.5 GPa, Xe(H 2 ) 8 crystallizes in a P3 - m1 structure that displays pressure-induced occupancy changes of two pairs of xenon atoms located on the 2c and 2d sites (while the third pair on yet another 2c site remains fully occupied). The occupancy becomes 1 at the P3 - m1 to R3 transition and all the xenon atoms occupy the 3d sites in the high-pressure structure. These pressure-induced changes in occupancy coincide with volume changes that maintain the average Xe:H 2 stoichiometry fixed at 1:8. The synchrotron x-ray diffraction and Raman measurements show that this unique hydrogen-bearing compound that can be synthesized at 4.2 GPa and 300 K, quenched at low temperatures to atmospheric pressure, and retained up to 90 K on subsequent warming
20. The roles of H2S and H2O2 in regulating AsA-GSH cycle in the leaves of wheat seedlings under drought stress.
Science.gov (United States)
Shan, Changjuan; Zhang, Shengli; Ou, Xingqi
2018-01-25
This paper investigated the roles of hydrogen sulfide (H 2 S) and hydrogen peroxide (H 2 O 2 ) and the possible relationship between them in regulating the AsA-GSH cycle in wheat leaves under drought stress (DS). Results showed that DS markedly increased the production of H 2 S and H 2 O 2 , the transcript levels and activities of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR); malondialdehyde (MDA) content; and electrolyte leakage (EL). Meanwhile, DS markedly reduced plant height and biomass. Above increases induced by drought stress except MDA content and EL were all suppressed by pretreatments with H 2 S synthesis inhibitor aminooxyaceticacid (AOA) and H 2 O 2 synthesis inhibitor diphenylene iodonium (DPI). Besides, pretreatments with AOA and DPI further significantly increased MDA content and EL and significantly reduced plant height and biomass under DS. DPI reduced the production of H 2 O 2 and H 2 S induced by DS. AOA also reduced the production of H 2 S and H 2 O 2 induced by DS. Pretreatments with NaHS + AOA and H 2 O 2 + DPI reversed above effects of AOA and DPI. Our results suggested that H 2 S and H 2 O 2 all participated in the up-regulation of AsA-GSH cycle in wheat leaves by DS and possibly affected each other.
1. Laboratory studies of H2SO4/H2O binary homogeneous nucleation from the SO2+OH reaction: evaluation of the experimental setup and preliminary results
Directory of Open Access Journals (Sweden)
M. Kulmala
2008-08-01
Full Text Available Binary homogeneous nucleation (BHN of sulphuric acid and water (H2SO4/H2O is one of the most important atmospheric nucleation processes, but laboratory observations of this nucleation process are very limited and there are also large discrepancies between different laboratory studies. The difficulties associated with these experiments include wall loss of H2SO4 and uncertainties in estimation of H2SO4 concentration ([H2SO4] involved in nucleation. We have developed a new laboratory nucleation setup to study H2SO4/H2O BHN kinetics and provide relatively constrained [H2SO4] needed for nucleation. H2SO4 is produced from the SO2+OH→HSO3 reaction and OH radicals are produced from water vapor UV absorption. The residual [H2SO4] were measured at the end of the nucleation reactor with a chemical ionization mass spectrometer (CIMS. Wall loss factors (WLFs of H2SO4 were estimated by assuming that wall loss is diffusion limited and these calculated WLFs were in good agreement with simultaneous measurements of the initial and residual [H2SO4] with two CIMSs. The nucleation zone was estimated from numerical simulations based on the measured aerosol sizes (particle diameter, Dp and [H2SO4]. The measured BHN rates (J ranged from 0.01–220 cm−3 s−1 at the initial and residual [H2SO4] from 108−1010 cm−3, a temperature of 288 K and relative humidity (RH from 11–23%; J increased with increasing [H2SO4] and RH. J also showed a power dependence on [H2SO4] with the exponential power of 3–8. These power dependences are consistent with other laboratory studies under similar [H2SO4] and RH, but different from atmospheric field observations which showed that particle number concentrations are often linearly dependent on [H2SO4]. These results, together with a higher [H2SO4] threshold (108–109 cm−3 needed to produce the unit J measured from the laboratory studies compared to the atmospheric conditions (106–107 cm−3, imply that H2SO4/H2O BHN alone is
2. MPK6 controls H2 O2-induced root elongation by mediating Ca2+ influx across the plasma membrane of root cells in Arabidopsis seedlings.
Science.gov (United States)
Han, Shuan; Fang, Lin; Ren, Xuejian; Wang, Wenle; Jiang, Jing
2015-01-01
Mitogen-activated protein kinases (MPKs) play critical roles in signalling and growth, and Ca(2+) and H2 O2 control plant growth processes associated with abscisic acid (ABA). However, it remains unclear how MPKs are involved in H2 O2 - and Ca(2+) -mediated root elongation. Root elongation in seedlings of the loss-of-function mutant Atmpk6 (Arabidopsis thaliana MPK6) was less sensitive to moderate H2 O2 or ABA than that in wild-type (WT) plants. The enhanced elongation was a result of root cell expansion. This effect disappeared when ABA-induced H2 O2 accumulation or the cytosolic Ca(2+) increase were defective. Molecular and biochemical evidence showed that increased expression of the cell wall peroxidase PRX34 in Atmpk6 root cells enhanced apoplastic H2 O2 generation; this promoted a cytosolic Ca(2+) increase and Ca(2+) influx across the plasma membrane. The plasma membrane damage caused by high levels of H2 O2 was ameliorated in a Ca(2+) -dependent manner. These results suggested that there was intensified PRX34-mediated H2 O2 generation in the apoplast and increased Ca(2+) flux into the cytosol of Atmpk6 root cells; that is, the spatial separation of apoplastic H2 O2 from cytosolic Ca(2+) in root cells prevented H2 O2 -induced inhibition of root elongation in Atmpk6 seedlings. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.
3. Line shape parameters for the H2O-H2 collision system for application to exoplanet and planetary atmospheres
Science.gov (United States)
Renaud, Candice L.; Cleghorn, Kara; Hartmann, Léna; Vispoel, Bastien; Gamache, Robert R.
2018-05-01
Water can be detected throughout the universe: in comets, asteroids, dwarf planets, the inner and outer planets in our solar system, cool stars, brown dwarfs, and on many exoplanets. Here the focus is on locations rich in hydrogen gas. To properly study these environments, there is a need for the line shape parameters for H2O transitions in collision with hydrogen. This work presents calculations of the half-width and line shift, made using the Modified Complex Robert-Bonamy (MCRB) formalism, at a number of temperatures. It is shown that this collision system is strongly off-resonance. For such conditions, the atom-atom part of the intermolecular potential dominates the interaction of the radiating and perturbing molecules. The atom-atom parameters were adjusted by fitting the H2O-H2 measurements of Brown and Plymate (1996). Several techniques were used to extract lines for which there is more confidence in the quality of the data. The final potential yields results that agree with the measurements with ∼0.3% difference and a 5.9% standard deviation. Using this potential, MCRB calculations were made for all transitions in the pure rotation, ν2, ν1, and ν3 bands. The structure of the line shape parameters and the temperature dependence of the half-width, as a function of the rotational and vibrational quantum numbers, are discussed. It is shown that the power law model of the T-dependence of the half-width is inadequate over large temperature ranges.
4. Supersaturation of dissolved H(2) and CO (2) during fermentative hydrogen production with N(2) sparging.
Science.gov (United States)
Kraemer, Jeremy T; Bagley, David M
2006-09-01
Dissolved H(2) and CO(2) were measured by an improved manual headspace-gas chromatographic method during fermentative H(2) production with N(2) sparging. Sparging increased the yield from 1.3 to 1.8 mol H(2)/mol glucose converted, although H(2) and CO(2) were still supersaturated regardless of sparging. The common assumption that sparging increases the H(2) yield because of lower dissolved H(2) concentrations may be incorrect, because H(2) was not lowered into the range necessary to affect the relevant enzymes. More likely, N(2) sparging decreased the rate of H(2) consumption via lower substrate concentrations.
5. Phase formation in the systems ZrO2-H2SO4-Na2SO4 (NaCl)-H2O
International Nuclear Information System (INIS)
Sozinova, Yu.P.; Motov, D.L.; Rys'kina, M.P.
1988-01-01
Formation of solid phases in the systems ZrO 2 - H 2 SO 4 - Na 2 SO 4 (NaCl) - H 2 O at 25 and 75 deg C is studied. Three basic Na 2 Zr(OH) 2 (SO 4 ) 2 x (0.2 - 0.4)H 2 O, NaZrOH(SO 4 ) 2 x H 2 O, NaZrO 0.5 (OH) 2 SO 4 x 2H 2 O and three normal sodium sulfatozirconates Na 2 Zr(SO 4 ) 3 x 3H 2 O, Na 4 Zr(SO 4 ) 4 x 3H 2 O, Na 6 Zr(SO 4 ) 5 x 4H 2 O have been isolated, their solubility and crystal optical properties are determined
6. Longitudinal sound velocities, elastic anisotropy, and phase transition of high-pressure cubic H2O ice to 82 GPa
Science.gov (United States)
Kuriakose, Maju; Raetz, Samuel; Hu, Qing Miao; Nikitin, Sergey M.; Chigarev, Nikolay; Tournat, Vincent; Bulou, Alain; Lomonosov, Alexey; Djemia, Philippe; Gusev, Vitalyi E.; Zerr, Andreas
2017-10-01
Water ice is a molecular solid whose behavior under compression reveals the interplay of covalent bonding in molecules and forces acting between them. This interplay determines high-pressure phase transitions, the elastic and plastic behavior of H2O ice, which are the properties needed for modeling the convection and internal structure of the giant planets and moons of the solar system as well as H2O -rich exoplanets. We investigated experimentally and theoretically elastic properties and phase transitions of cubic H2O ice at room temperature and high pressures between 10 and 82 GPa. The time-domain Brillouin scattering (TDBS) technique was used to measure longitudinal sound velocities (VL) in polycrystalline ice samples compressed in a diamond anvil cell. The high spatial resolution of the TDBS technique revealed variations of VL caused by elastic anisotropy, allowing us to reliably determine the fastest and the slowest sound velocity in a single crystal of cubic H2O ice and thus to evaluate existing equations of state. Pressure dependencies of the single-crystal elastic moduli Ci j(P ) of cubic H2O ice to 82 GPa have been obtained which indicate its hardness and brittleness. These results were compared with ab initio calculations. It is suggested that the transition from molecular ice VII to ionic ice X occurs at much higher pressures than proposed earlier, probably above 80 GPa.
7. The effects of CO addition on the autoignition of H-2, CH4 and CH4/H-2 fuels at high pressure in an RCM
NARCIS (Netherlands)
Gersen, Sander; Darmeveil, Harry; Levinsky, Howard
2012-01-01
Autoignition delay times of stoichiometric and fuel-lean (phi = 0.5) H-2, H-2/CO, CH4, CH4/CO, CH4/H-2 and CH4/CO/H-2 mixtures have been measured in an Rapid Compression Machine at pressures ranging from 20 to 80 bar and in the temperature range 900-1100K. The effects of CO addition on the ignition
8. Effect of KOH Concentration and Anions on the Performance of a Ni-H2 Battery Positive Plate
Science.gov (United States)
Vaidyanathan, Hari; Robbins, Kathleen; Gopalakrishna, M. Rao
1996-01-01
The capacity and voltage behavior of electrochemically impregnated sintered nickel positive plates was examined by galvanostatic charging and discharging in a flooded electrolyte cell. Three different concentrations of potassium hydroxide (KOH) (40, 31, and 26 percent) and 31 percent KOH containing dissolved nitrate, sulfate, or silicate were investigated. The end-of-charge voltage at C/10 charge and at 10 degrees C showed the following order: 40 percent KOH greater than 31 percent KOH alone and in the presence of the anions greater than 26 percent KOH. The mid discharge voltage at C/2 discharge was higher in 26 percent KOH, almost the same for 31 percent KOH with and without added contaminants, and much lower for 40 percent KOH. The plate capacity was marginally affected by cycling in all cases except for 40 percent KOH, where the capacity declined after 1,000 cycles at 80 percent depth of discharge (DOD). At the end of cycling, all the plates tested experienced a weight loss, except in the case of 31 percent KOH, as a result of active material extrusion. Cyclic voltammetry of miniature electrodes in 31 percent KOH showed that the cathodic peak potentials are less polarized in the presence and absence of silicate at -5 degrees C compared to 25 degrees C indicating a slightly higher voltage during discharge in a Ni-H2 battery. Futhermore, the features of the current-potential profile were practically unchanged in the presence of silicate.
9. Characterisation of the coke formed during metal dusting of iron in CO-H2-H2O gas mixtures
International Nuclear Information System (INIS)
Zhang, J.; Schneider, A.; Inden, G.
2003-01-01
Carbon deposits formed on the surface of iron samples during carburisation at 700 deg. C in a gas mixture of 75%CO-24.81%H 2 -0.19%H 2 O were characterised by using scanning electron microscopy (SEM), X-ray diffraction (XRD), Moessbauer spectroscopy and transmission electron microscopy (TEM). Cross-section observation of the iron sample by light optical microscopy revealed the formation of cementite after only 10 min reaction, together with a thin layer of graphite. After 4 h reaction, a thick coke layer was formed on top of the cementite surface. SEM surface observation indicated the formation of filamentous carbon in the coke layer. Further analysis of the coke by XRD and Moessbauer showed the presence of mainly Fe 3 C and small amount of Fe 2 C but no metallic iron in the carbon deposit. TEM analysis of the coke detected very convoluted filaments with iron-containing particles at the tip or along their length. These particles were identified to be cementite by selected area diffraction. Carbon deposits produced at the same temperature but with other gas compositions were also analysed by using XRD. It was found that with a low content of CO, e.g. 5%, both α-Fe and Fe 3 C were detected in the coke. Increasing CO content to more than 30%, iron carbide was the only iron-containing phase
10. H2 Equilibrium Pressure with a Neg-Coated Vacuum Chamber as a Function of Temperature and H2 Concentration
CERN Document Server
2006-01-01
Non Evaporable Getter (NEG) coating is used in the Large Hadron Collider (LHC) room-temperature sections to ensure a low residual gas pressure for its properties of distributed pumping, low outgassing and desorption under particle bombardment; and to limit or cure electron cloud build-up due to its low secondary electron emission. In certain regions of the LHC, and in particular close to the beam collimators, the temperature of the vacuum chamber is expected to rise due to energy deposition from particle losses. Hydrogen molecules are pumped by the NEG via dissociation on the surface, sorption at the superficial sites and diffusion into the NEG bulk. In the case of hydrogen, the sorption is thermally reversible, causing the dissociation pressure to increase with NEG temperature and amount of H2 pumped. Measurements were carried out on a stainless steel chamber coated with TiZrV NEG as a function of the H2 concentration and the chamber temperature, to estimate the residual gas pressure in the collimator region...
11. Temperature dependence of third order ion molecule reactions. The reaction H+3 + 2H2 = H+5 + H2
International Nuclear Information System (INIS)
Hiraoka, K.; Kebarle, P.
1975-01-01
The rate constants k 1 for Reaction (1): H + 3 +2H 2 = H + 5 +H 2 were measured in the temperature range 100--300 degreeK. The temperature dependence of k 1 has the form k 1 proportionalT - /subn/, where n=2.3. Pierce and Porter have reported a much stronger negative temperature dependence with n=4.6. The difference arises from a determination of k 1 at 300 degreeK obtained by Arifov and used by Porter. The present k 1 (300 degreeK) =9times10 -30 (cm 6 molecules -2 center-dotsec -1 ). This is more than an order of magnitude larger than the Arifov value. The temperature dependence of third body dependent association reactions like (1) is examined on the basis of the energy transfer theory and the recently proposed trimolecular complex transition state theory by Meot-Ner, Solomon, Field, and Gershinowitz. The temperature dependence of the rate constant for the reverse reaction (-1) is obtained from k 1 and the previously determined temperature dependence of the equilibria (1). k/sub -//sub 1/ gives a good straight line Arrhenius plot leading to k/sub -//sub 1/ =8.7times10 -6 exp(-8.4/RT) cm 3 molecules -1 center-dotsec -1 . The activation energy is in kcal/mole. The preexponential factor is much larger than the rate constant for Langevin collisions. This is typical for pyrolysis of ions involving second order activation
12. Atmospheric pressure plasma jet utilizing Ar and Ar/H2O mixtures and its applications to bacteria inactivation
International Nuclear Information System (INIS)
Cheng Cheng; Shen Jie; Xiao De-Zhi; Xie Hong-Bing; Lan Yan; Fang Shi-Dong; Meng Yue-Dong; Chu Paul K
2014-01-01
An atmospheric pressure plasma jet generated with Ar with H 2 O vapor is characterized and applied to inactivation of Bacillus subtilis spores. The emission spectra obtained from Ar/H 2 O plasma shows a higher intensity of OH radicals compared to pure argon at a specified H 2 O concentration. The gas temperature is estimated by comparing the simulated spectra of the OH band with experimental spectra. The excitation electron temperature is determined from the Boltzmann's plots and Stark broadening of the hydrogen Balmer H β line is applied to measure the electron density. The gas temperature, excitation electron temperature, and electron density of the plasma jet decrease with the increase of water vapor concentration at a fixed input voltage. The bacteria inactivation rate increases with the increase of OH generation reaching a maximum reduction at 2.6% (v/v) water vapor. Our results also show that the OH radicals generated by the Ar/H 2 O plasma jet only makes a limited contribution to spore inactivation and the shape change of the spores before and after plasma irradiation is discussed. (physics of gases, plasmas, and electric discharges)
13. Sequencing treatment of industrial wastewater with ultraviolet/H2O2 advanced oxidation and moving bed bioreactor
Directory of Open Access Journals (Sweden)
Mohammad Mehdi Mehrabani Ardekani
2015-01-01
Full Text Available Aims: The main purpose of this study was to determine the efficiency of a sequencing treatment including ultraviolet (UV/H 2 O 2 oxidation followed by a moving bed bioreactor (MBBR. Materials and Methods: Effect of solution pH, reaction time, and H 2 O 2 concentration were investigated for an industrial wastewater sample. The effluent of the advanced oxidation processes unit was introduced to the MBBR operated for three hydraulic retention times of 4, 8, and 12 h. Results: The optimum condition for industrial wastewater treatment via advanced oxidation was solution pH: 7, H 2 O 2 dose: 1000 mg/L and 90 min reaction time. These conditions led to 74.68% chemical oxygen demand (COD removal and 66.15% biochemical oxygen demand (BOD 5 removal from presedimentation step effluent that initially had COD and BOD 5 contents of 4,400 and 1,950 mg/L, respectively. Conclusion: Combination of UV/H 2 O 2 advanced oxidation with MBBR could result in effluents that meet water quality standards for discharge to receiving waters.
14. Study of the properties of plasma of CH4/H2 and its interactions with liquid hydrocarbons
International Nuclear Information System (INIS)
Gambus, G.; Patino, P.
2003-01-01
Properties of a CH 4 /H 2 plasma, as a reducing agent in heterogeneous reactions with one olefin hydrocarbon, were studied in this work. The characterization of the plasma was carried out by means of optical emission spectroscopy, by varying the gas composition (CH 4 /H 2 ) and the working pressure, in a radio frequency discharge. The variation of the relative populations of H and CH radicals was followed, at pressures between 0.001 and 0.4 mbar and CH 4 /H 2 proportions 1:1 to 1:5. The conditions selected for treating squalene were 0.1 mbar and CH 4 /H 2 of 1:5. Although these conditions did not yield the maximum intensities for the two signals, these were strong enough and black carbon and polymers ceased from being produced under this regime. At 5 C, more than two double bonds per molecule, out of six, were hydrogenated with the plasma in 12 hours. (Author)
15. Staining Against Phospho-H2AX (gamma-H2AX) as a Marker for DNA Damage and Genomic Instability in Cancer Tissues and Cells
NARCIS (Netherlands)
Nagelkerke, A.P.; Span, P.N.
2016-01-01
Phospho-H2AX or gamma-H2AX- is a marker of DNA double-stranded breaks and can therefore be used to monitor DNA repair after, for example, irradiation. In addition, positive staining for phospho-H2AX may indicate genomic instability and telomere dysfunction in tumour cells and tissues. Here, we
16. Does residual H2O2 result in inhibitory effect on enhanced anaerobic digestion of sludge pretreated by microwave-H2O2 pretreatment process?
Science.gov (United States)
Liu, Jibao; Jia, Ruilai; Wang, Yawei; Wei, Yuansong; Zhang, Junya; Wang, Rui; Cai, Xing
2017-04-01
This study investigated the effects of residual H 2 O 2 on hydrolysis-acidification and methanogenesis stages of anaerobic digestion after microwave-H 2 O 2 (MW-H 2 O 2 ) pretreatment of waste activated sludge (WAS). Results showed that high sludge solubilization at 35-45 % was achieved after pretreatment, while large amounts of residual H 2 O 2 remained and refractory compounds were thus generated with high dosage of H 2 O 2 (0.6 g H 2 O 2 /g total solids (TS), 1.0 g H 2 O 2 /g TS) pretreatment. The residual H 2 O 2 not only inhibited hydrolysis-acidification stage mildly, such as hydrolase activity, but also had acute toxic effect on methanogens, resulting in long lag phase, low methane yield rate, and no increase of cumulative methane production during the 30-day BMP tests. When the low dosage of H 2 O 2 at 0.2 g H 2 O 2 /g TS was used in MW-H 2 O 2 pretreatment, sludge anaerobic digestion was significantly enhanced. The cumulative methane production increased by 29.02 %, but still with a lag phase of 1.0 day. With removing the residual H 2 O 2 by catalase, the initial lag phase of hydrolysis-acidification stage decreased from 1.0 to 0.5 day.
17. Evaluation of plasma H2S levels and H2S synthesis in streptozotocin induced Type-2 diabetes-an experimental study based on Swietenia macrophylla seeds
Directory of Open Access Journals (Sweden)
Moumita Dutta
2014-05-01
Conclusions: Although considering a small sample size, it can conclude that the fasting blood glucose levels are inversely related to plasma H2S levels as well as H2S synthesis activity in plasma and the extract of S. macrophylla is associated with increased plasma H2S levels with effective lowering of blood glucose in streptozotocin induced diabetic rats.
18. Characterization of mussel H2A.Z.2: a new H2A.Z variant preferentially expressed in germinal tissues from Mytilus.
Science.gov (United States)
Rivera-Casas, Ciro; González-Romero, Rodrigo; Vizoso-Vazquez, Ángel; Cheema, Manjinder S; Cerdán, M Esperanza; Méndez, Josefina; Ausió, Juan; Eirin-Lopez, Jose M
2016-10-01
Histones are the fundamental constituents of the eukaryotic chromatin, facilitating the physical organization of DNA in chromosomes and participating in the regulation of its metabolism. The H2A family displays the largest number of variants among core histones, including the renowned H2A.X, macroH2A, H2A.B (Bbd), and H2A.Z. This latter variant is especially interesting because of its regulatory role and its differentiation into 2 functionally divergent variants (H2A.Z.1 and H2A.Z.2), further specializing the structure and function of vertebrate chromatin. In the present work we describe, for the first time, the presence of a second H2A.Z variant (H2A.Z.2) in the genome of a non-vertebrate animal, the mussel Mytilus. The molecular and evolutionary characterization of mussel H2A.Z.1 and H2A.Z.2 histones is consistent with their functional specialization, supported on sequence divergence at promoter and coding regions as well as on varying gene expression patterns. More precisely, the expression of H2A.Z.2 transcripts in gonadal tissue and its potential upregulation in response to genotoxic stress might be mirroring the specialization of this variant in DNA repair. Overall, the findings presented in this work complement recent reports describing the widespread presence of other histone variants across eukaryotes, supporting an ancestral origin and conserved role for histone variants in chromatin.
19. Electron scattering from H2+: Resonances in the Π symmetries
International Nuclear Information System (INIS)
Collins, L.A.; Schneider, B.I.; Noble, C.J.
1992-01-01
We present the results of calculations for e - +H 2 + scattering in the region below the first excited state. We employ three distinct and independent methods, close-coupling linear algebraic, effective-optical-potential linear algebraic, and R matrix, to examine the collision at the highest level of sophistication and to provide a valuable check on the results of a single technique. For the 1 Π u and 3 Π u symmetries, we find strong interference effects between various autoionizing series, leading to significant variations of the resonance width with internuclear separation R. Such variations may have profound effects on such processes as photoionization, dissociation, and recombination. For the 1 Π g and 3 Π g symmetries, we observe monotonic behavior of the width with R and find no evidence of strong interference effects or rapid changes
20. Fuel cell bus operation, system investigation H2 bus
International Nuclear Information System (INIS)
Anon.
1992-01-01
The WP covers two tasks: - Prepartion of Technical Catalogue: In cooperation with ICIL, AR have compiled a technical catalogue, providing the impartial descriptions, both of existing technology and regulations, and the likely future developments of these, as to remedy the first problem faced by a potential hydrogen bus fleet operator viz the absence of an impartial description of the available vehicle and fuels systems together with the absence of a description of regulatory and safety factors which need consideration. - Fuel Cell Bus Operation - System Investigation H 2 Bus: The application of fuel cell electric generation systems to hybrid electrical buses or electrical busses without any storage system on board is considered. The task will cover safety and environmental aspects, a cost estimate and a market evaluation. (orig.)
1. Utilization of membranes for H2O recycle system
Science.gov (United States)
Ohya, H.; Oguchi, M.
1986-01-01
Conceptual studies of closed ecological life support systems (CELSS) carried out at NAL in Japan for a water recycle system using membranes are reviewed. The system will treat water from shower room, urine, impure condensation from gas recycle system, and so on. The H2O recycle system is composed of prefilter, ultrafiltration membrane, reverse osmosis membrane, and distillator. Some results are shown for a bullet train of toilet-flushing water recycle equipment with an ultraviltration membrane module. The constant value of the permeation rate with a 4.7 square meters of module is about 70 1/h after 500th of operation. Thermovaporization with porous polytetrafluorocarbon membrane is also proposed to replce the distillator.
2. Fabry-Perot observations of Comet Halley H2O(+)
International Nuclear Information System (INIS)
Scherb, F.; Roesler, F.L.D.; Harlander, J.; Magee-sauer, K.
1990-01-01
Fabry-Perot scanning spectrometer observations of Comet Halley's H 2 O(+) emissions have yielded 6158.64 and 6158.85 A spin doublet data at distances in the range of 0 to 2 million km from the comet heat in the antisunward direction. Cometary plasma outflow velocities were ascertained on the basis of the emissions' Doppler shifts, yielding results that were mostly but not exclusively consistent with the plasma's constant antisunward acceleration; the acceleration varied from night to night of observations over a 30-300 cm/sec range. The unusual plasma kinematics of December 14-15, 1985, and January 10, 1986, may be associated with the tail-disconnection activity observed by others. 30 refs
3. Polarizability tensor invariants of H2, HD, and D2
Science.gov (United States)
Raj, Ankit; Hamaguchi, Hiro-o.; Witek, Henryk A.
2018-03-01
We report an exhaustive compilation of wavelength-dependent matrix elements over the mean polarizability (α ¯ ) and polarizability anisotropy (γ) operators for the rovibrational states of the H2, HD, and D2 molecules together with an accompanying computer program for their evaluation. The matrix elements can be readily evaluated using the provided codes for rovibrational states with J = 0-15 and v = 0-4 and for any laser wavelengths in the interval 182.25-1320.6 nm corresponding to popular, commercially available lasers. The presented results substantially extend the scope of the data available in the literature, both in respect of the rovibrational transitions analyzed and the range of covered laser frequencies. The presented detailed tabulation of accurate polarizability tensor invariants is essential for successful realization of our main long-term goal: developing a universal standard for determining absolute Raman cross sections and absolute Raman intensities in experimental Rayleigh and Raman scattering studies of molecules.
4. D2-H2 equilibration over γ-irradiated zeolites
International Nuclear Information System (INIS)
Novakova, J.; Wichterlova, B.
1987-01-01
D 2 -H 2 equilibration was studied at 77 and 298 K over HY, AlHY, HZSM-5 and Alsub(x)Osub(y)HZSM-5 zeolites which had been γ-irradiated at 77 and/or 298 K. The exchange rate was found to be higher at the lower temperature regardless of the temperature of irradiation. Moreover, at 77 K the exchange rates were similar and more stable over the individual zeolites than at 298 K, thus indicating a common reaction path at 77 K. The exchange rate at 298 K depended on the zeolite type: it was more stable and higher over HZSM-5 than over HY, and extra-lattice Al increased both these properties on HY as well as on HZSM-5. The reaction mechanism is discussed in connection with the nature of defects generated by γ-irradiation. (author)
5. Laser diagnostics of high vibrational and rotational H2-states
International Nuclear Information System (INIS)
Mosbach, Th.; Schulz-von der Gathen, V.; Doebele, H.F.
2002-01-01
We report on measurements of vibrational and rotational excited electronic-ground-state hydrogen molecules in a magnetic multipole plasma source by LIF with VUV radiation. The measurements are taken after rapid shut-off of the discharge current. Absolute level populations are obtained using Rayleigh scattering calibration with Krypton. The theoretically predicted suprathermal population of the vibrational distribution is clearly identified. We found also non-Boltzmann rotational distributions for the high vibrational states. The addition of noble gases (Argon and Xenon) to hydrogen leads to a decrease of the vibrational population. (Abstract Copyright [2002], Wiley Periodicals, Inc.)
6. Compact Intracloud Discharges
Energy Technology Data Exchange (ETDEWEB)
Smith, David A. [Univ. of Colorado, Boulder, CO (United States)
1998-11-01
thunderstorms in the southwestern United States (US). The events occurred at altitudes between 8 and 11 km above mean sea level (MSL). Radar reflectivity data from two of the storms showed that CIDS occurred in close spatial proximity to thunderstorm cores with peak radar reflectivities of 47 to 58 dBZ. Over one hundred CIDS were also recorded from tropical cyclone Fausto off the coast of Mexico. These events occurred at altitudes between 15 and 17 km MSL. CIDS are singular discharges that usually occur in temporal isolation from other thunderstorm radio emissions on time scales of at least a few milliseconds. Calculations show that the discharges are vertically oriented and 300 to 1000 m in spatial extent. They produce average currents of several tens to a couple hundred kA for time periods of approximately 15 ps. Based on the results of a charge distribution model, the events occur in thunderstorm regions with charge densities on the order of several tens of nC/m3 and peak electric fields that are greater than 1 x 106 V/m. Both of these values are an order of magnitude greater than values previously measured orinfemed frominsitu thunderstom measurements. Theunique radio emissions from CIDS, in combination with their unprecedented physical characteristics, clearly distinguish the events from other types of previously observed thunderstorm electrical processes.
7. Tennis elbow surgery - discharge
Science.gov (United States)
... epicondylitis surgery - discharge; Lateral tendinosis surgery - discharge; Lateral tennis elbow surgery - discharge ... long as you are told. This helps ensure tennis elbow will not return. You may be prescribed a ...
8. Ankle replacement - discharge
Science.gov (United States)
... total - discharge; Total ankle arthroplasty - discharge; Endoprosthetic ankle replacement - discharge; Osteoarthritis - ankle ... You had an ankle replacement. Your surgeon removed and reshaped ... an artificial ankle joint. You received pain medicine and were ...
9. Hip fracture - discharge
Science.gov (United States)
... neck fracture repair - discharge; Trochanteric fracture repair - discharge; Hip pinning surgery - discharge ... in the hospital for surgery to repair a hip fracture, a break in the upper part of ...
10. Asthma - child - discharge
Science.gov (United States)
Pediatric asthma - discharge; Wheezing - discharge; Reactive airway disease - discharge ... Your child has asthma , which causes the airways of the lungs to swell and narrow. In the hospital, the doctors and nurses helped ...
11. Study of the ionization of H+2 ions in strong laser fields
International Nuclear Information System (INIS)
Odenweller, Matthias
2010-01-01
In the framework of this thesis it has been succeeded to develop a worldwide unique measurement apparatur, by which hydrogen-molecule ions can be ionized by means of short laser pulses and the reaction product kinematically completely measured. For this a detection method following the Coltrims technique, in which both protons and electrons can be detected over the complete spatial angle. The H + 2 ions origin from a high-frequency ion source and are accelerated to 400 keV. This ion beam is overlapped with a 780-nm laser pulse othe pulse length 40 fs. After the reaction the molecule ions fragments either via the dissociation channel H + 2 +nhν→H+H + or via an ionization followed by a Coulomb explosion: H + 2 +nhν→H + +H + +e - . The projectiles are detected after a drift path of about 3 m on an ion detector. For the detection of the electrons a special spectrometer was concipated. In the reaction it comes by the comparatively long pulse length already at low intensities to dissociation processes. The dissociating molecule reaches still during the increasing side of the laser pulse in this way distances, in which the charge-resonance-enhanced-ionization (CREI) can take place. Also the angular distribution of the measured protons lying in a very small angular range around the polarization direction of the laser suggests that CREI is the dominant ionization process. At circular polarization however a netto-acceleration of the electrons perpendicularly to the direction of the electric field at the ionization time takes place, so that the measurement of the electron momenta represents a suited measurement quantity for the study of the ionization process. By this way angular distributions of the electrons relatively to the internuclear axis within the polarization plane could be measured.
12. Catalase activity is stimulated by H2O2 in rich culture medium and is required for H2O2 resistance and adaptation in yeast ☆
OpenAIRE
Martins, Dorival; English, Ann M.
2014-01-01
Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to...
13. Crystal-field-driven redox reactions: How common minerals split H2O and CO2 into reduced H2 and C plus oxygen
Science.gov (United States)
Freund, F.; Batllo, F.; Leroy, R. C.; Lersky, S.; Masuda, M. M.; Chang, S.
1991-01-01
It is difficult to prove the presence of molecular H2 and reduced C in minerals containing dissolved H2 and CO2. A technique was developed which unambiguously shows that minerals grown in viciously reducing environments contain peroxy in their crystal structures. The peroxy represent interstitial oxygen atoms left behind when the solute H2O and/or CO2 split off H2 and C as a result of internal redox reactions, driven by the crystal field. The observation of peroxy affirms the presence of H2 and reduced C. It shows that the solid state is indeed an unusual reaction medium.
14. FORMATION OF S-BEARING SPECIES BY VUV/EUV IRRADIATION OF H2S-CONTAINING ICE MIXTURES: PHOTON ENERGY AND CARBON SOURCE EFFECTS
International Nuclear Information System (INIS)
Chen, Y.-J.; Juang, K.-J.; Qiu, J.-M.; Chu, C.-C.; Yih, T.-S.; Nuevo, M.; Jiménez-Escobar, A.; Muñoz Caro, G. M.; Wu, C.-Y. R.; Fung, H.-S.; Ip, W.-H.
2015-01-01
Carbonyl sulfide (OCS) is a key molecule in astrobiology that acts as a catalyst in peptide synthesis by coupling amino acids. Experimental studies suggest that hydrogen sulfide (H 2 S), a precursor of OCS, could be present in astrophysical environments. In the present study, we used a microwave-discharge hydrogen-flow lamp, simulating the interstellar UV field, and a monochromatic synchrotron light beam to irradiate CO:H 2 S and CO 2 :H 2 S ice mixtures at 14 K with vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) photons in order to study the effect of the photon energy and carbon source on the formation mechanisms and production yields of S-containing products (CS 2 , OCS, SO 2 , etc.). Results show that (1) the photo-induced OCS production efficiency in CO:H 2 S ice mixtures is higher than that of CO 2 :H 2 S ice mixtures; (2) a lower concentration of H 2 S enhances the production efficiency of OCS in both ice mixtures; and (3) the formation pathways of CS 2 differ significantly upon VUV and EUV irradiations. Furthermore, CS 2 was produced only after VUV photoprocessing of CO:H 2 S ices, while the VUV-induced production of SO 2 occurred only in CO 2 :H 2 S ice mixtures. More generally, the production yields of OCS, H 2 S 2 , and CS 2 were studied as a function of the irradiation photon energy. Heavy S-bearing compounds were also observed using mass spectrometry during the warm-up of VUV/EUV-irradiated CO:H 2 S ice mixtures. The presence of S-polymers in dust grains may account for the missing sulfur in dense clouds and circumstellar environments
15. Prostate brachytherapy - discharge
Science.gov (United States)
Implant therapy - prostate cancer - discharge; Radioactive seed placement - discharge ... You had a procedure called brachytherapy to treat prostate cancer. Your treatment lasted 30 minutes or more, ...
16. Ion-exchange synthesis and improved Li insertion property of lithiated H2Ti12O25 as a negative electrode material for lithium-ion batteries
Directory of Open Access Journals (Sweden)
Kunimitsu Kataoka
2016-03-01
Full Text Available We successfully prepared the lithiated H2Ti12O25 sample by the H+/Li+ ion exchange synthetic technique in the molten LiNO3 at 270 °C using H2Ti12O25 as a starting compound. Chemical composition of the obtained lithiated H2Ti12O25 sample was determined to be H1.05Li0.35Ti12O25-δ having δ = 0.3 by ICP-AES and DTA-TG analyses. The H+/Li+ ion exchange was also confirmed by powder XRD, 1H-MAS NMR, and 7Li-MAS NMR measurements. Electrochemical Li insertion and extraction measurements revealed that the initial coulombic efficiency was improved from 88% in H2Ti12O25 to 93% in the lithiated H2Ti12O25 sample. In addition, superior capacity retention properties for the charge and discharge cycling performance and good charge rate capability of the present lithiated H2Ti12O25 were confirmed in the electrochemical measurements. Accordingly, the lithiated H2Ti12O25 is suggested to be one of the promising high-voltage and high-capacity oxide negative electrodes in advanced lithium-ion batteries.
17. Double-Exponentially Decayed Photoionization in CREI Effect: Numerical Experiment on 3D H2+
International Nuclear Information System (INIS)
Feng, Li; Ting-Ying, Wang; Gui-Zhong, Zhang; Wang-Hua, Xiang; III, W. T. Hill
2008-01-01
On the platform of the 3D H 2 + system, we perform a numerical simulation of its photoionization rate under excitation of weak to intense laser intensities with varying pulse durations and wavelengths. A novel method is proposed for calculating the photoionization rate: a double exponential decay of ionization probability is best suited for fitting this rate. Confirmation of the well-documented charge-resonance-enhanced ionization (CREI) effect at medium laser intensity and finding of ionization saturation at high light intensity corroborate the robustness of the suggested double-exponential decay process. Surveying the spatial and temporal variations of electron wavefunctions uncovers a mechanism for the double-exponentially decayed photoionization probability as onset of electron ionization along extra degree of freedom. Henceforth, the new method makes clear the origins of peak features in photoionization rate versus internuclear separation. It is believed that this multi-exponentially decayed ionization mechanism is applicable to systems with more degrees of motion
18. Uranous nitrate production for purex process applications using PtO2 catalyst and H2/H2-gas mixtures
International Nuclear Information System (INIS)
Sreenivasa Rao, K.; Shyamali, R.; Narayan, C.V.; Patil, A.R.; Jambunathan, U.; Ramanujam, A.; Kansara, V.P.
2003-04-01
In the Purex process of spent fuel reprocessing. the twin objectives- decontamination and partitioning are achieved by extracting uranium (VI) and plutonium (IV) together in the solvent 30% TBP-dodecane and then selectively reducing Pu (IV) to Pu (III) in which valency it is least extractable in the solvent. Uranous nitrate stabilized with hydrazine nitrate is the widely employed partitioning agent. The conventional method of producing U(IV) is by the electrolytic reduction of uranyl nitrate with hydrazine nitrate as uranous ion stabilizer. Tre percentage conversion of U(VI) to U(IV) obtained in this method is 50 -60 %. The use of this solution as partitioning agent leads not only to the dilution of the plutonium product but also to increase in uranium processing load by each externally fed uranous nitrate batch. Also the oxide coating of the anode, TSIA (Titanium Substrate Insoluble Anode) wears out after a certain period of operation. This necessitates recoating which is quite cumbersome considering the amount of the decontamination involved. An alternative to the conventional electrolytic method of reduction of uranyl nitrate to uranous nitrate was explored at FRD laboratory .The studies have revealed that near 100% uranous nitrate can be produced by reducing uranyl nitrate with H 2 gas or H 2 (8%)- Ar/N 2 gas mixture in presence of PtO 2 catalyst. This report describes the laboratory scale studies carried out to optimize the various parameters. Based on these studies reduction of uranyl nitrate on a pilot plant scale was carried out. The design and operation of the reductor column and also the various studies carried out in the pilot plant studies are discussed. Near 100% conversion of uranyl nitrate to uranous nitrate and also the redundancy of supply of electrical energy make this process a viable alternative to the existing electrolytic method. (author)
19. 26 CFR 1.642(h)-2 - Excess deductions on termination of an estate or trust.
Science.gov (United States)
2010-04-01
... trust. 1.642(h)-2 Section 1.642(h)-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Estates, Trusts, and Beneficiaries § 1.642(h)-2...)) in excess of gross income, the excess is allowed under section 642(h)(2) as a deduction to the...
20. The histone variant macroH2A is an epigenetic regulator of key developmental genes
DEFF Research Database (Denmark)
Buschbeck, Marcus; Uribesalgo, Iris; Wibowo, Indra
2009-01-01
The histone variants macroH2A1 and macroH2A2 are associated with X chromosome inactivation in female mammals. However, the physiological function of macroH2A proteins on autosomes is poorly understood. Microarray-based analysis in human male pluripotent cells uncovered occupancy of both macroH2A ...
1. Anti-H-Y responses of H-2b mutant mice.
Science.gov (United States)
Simpson, E; Gordon, R D; Chandler, P R; Bailey, D
1978-10-01
Two strains of H-2b mutant mice, H-2ba and H-2bf, in which the mutational event took place at H-2K, make anti-H-Y cytotoxic T cell responses which are H-2-restricted, Db-associated and indistinguishable in target cell specificity from those of H-2b mice. Thus, alteration of the H-2K molecule affects neither the Ir gene controlling the response, nor the associative antigen. On the other hand, one H-2Db mutant strain, H-2bo, although it makes a good anti-H-Y cytotoxic response, shows target cell specificity restricted to its own Dbo antigen(s), and neither H-2b, H-2ba or H-2bf anti-H-Y cytotoxic cells kill H-2bo male target cells. Thus, the alteration of the H-2Db molecule does not affect the Ir gene of H-2b mice, but it does alter the H-2Db-associative antigen.
2. H2-rich fluids from serpentinization: geochemical and biotic implications.
Science.gov (United States)
Sleep, N H; Meibom, A; Fridriksson, Th; Coleman, R G; Bird, D K
2004-08-31
Metamorphic hydration and oxidation of ultramafic rocks produces serpentinites, composed of serpentine group minerals and varying amounts of brucite, magnetite, and/or FeNi alloys. These minerals buffer metamorphic fluids to extremely reducing conditions that are capable of producing hydrogen gas. Awaruite, FeNi3, forms early in this process when the serpentinite minerals are Fe-rich. Olivine with the current mantle Fe/Mg ratio was oxidized during serpentinization after the Moon-forming impact. This process formed some of the ferric iron in the Earth's mantle. For the rest of Earth's history, serpentinites covered only a small fraction of the Earth's surface but were an important prebiotic and biotic environment. Extant methanogens react H2 with CO2 to form methane. This is a likely habitable environment on large silicate planets. The catalytic properties of FeNi3 allow complex organic compounds to form within serpentinite and, when mixed with atmospherically produced complex organic matter and waters that circulated through basalts, constitutes an attractive prebiotic substrate. Conversely, inorganic catalysis of methane by FeNi3 competes with nascent and extant life. Copyright 2004 The National Academy of Sciencs of the USA
3. Interpretation of the H2O maser outbursts in Orion
International Nuclear Information System (INIS)
Strel'nitskij, V.S.
1982-01-01
It is shown, that the H 2 O maser that flared up in Orion (+8 km/s) was partly unsaturated. The anti-correlation between the line width and intensity, the asymmetry of the profile and the changes of the visibility function within it are explained by blending of two componenets, one of which has experienced a flare. From the observed polarization properties the upper limit to the electron density (nsub(e) 5 cm -3 ), the strength of the magnetic field (B approximately 10 -2 G) and its direction (position angle phi approximately -15 deg) within the source are deduced. According to the proposed physical model the source is a gas condensation, pressed, heated and accelerated by the strong stellar wind from a young star (possibly IRc4). The maser is pumped by the CCr-process at sup(n)H approximately 10 11 -10 12 cm -3 . If the condensation is a remnant of a circumstellar gas-dust disk, the magnetic field within the disk must be essentially azimuthal [ru
4. Solid-state photoelectrochemical H2 generation with gaseous reactants
International Nuclear Information System (INIS)
Iwu, Kingsley O.; Galeckas, Augustinas; Kuznetsov, Andrej Yu.; Norby, Truls
2013-01-01
Photocurrent and H 2 production were demonstrated in an all solid-state photoelectrochemical cell employing gaseous methanol and water vapour at the photoanode. Open circuit photovoltage of around −0.4 V and short circuit photocurrent of up to 250 μA/cm 2 were obtained. At positive bias, photocurrent generation was limited by the irradiance, i.e., the amount of photogenerated charge carriers at the anode. Time constants and impedance spectra showed an electrochemical capacitance of the cell of about 15 μF/cm 2 in the dark, which increased with increasing irradiance. With only water vapour at the anode, the short circuit photocurrent was about 6% of the value with gaseous methanol and water vapour. The photoanode and electrocatalyst on carbon paper support were affixed to the proton conducting membrane using Nafion ® as adhesive, an approach that yielded photocurrents up to 15 times better than that of a cell assembled by hot-pressing, in spite of the overall cell resistance of the latter being up to five times less than that of the former. This is attributed, at least partially, to reactants being more readily available at the photoanode of the better performing cell
5. Advanced oxidation removal of hypophosphite by O3/H2O2 combined with sequential Fe(II) catalytic process.
Science.gov (United States)
Zhao, Zilong; Dong, Wenyi; Wang, Hongjie; Chen, Guanhan; Wang, Wei; Liu, Zekun; Gao, Yaguang; Zhou, Beili
2017-08-01
Elimination of hypophosphite (HP) was studied as an example of nickel plating effluents treatment by O 3 /H 2 O 2 and sequential Fe(II) catalytic oxidation process. Performance assessment performed with artificial HP solution by varying initial pH and employing various oxidation processes clearly showed that the O 3 /H 2 O 2 ─Fe(II) two-step oxidation process possessed the highest removal efficiency when operating under the same conditions. The effects of O 3 dosing, H 2 O 2 concentration, Fe(II) addition and Fe(II) feeding time on the removal efficiency of HP were further evaluated in terms of apparent kinetic rate constant. Under improved conditions (initial HP concentration of 50 mg L -1 , 75 mg L -1 O 3 , 1 mL L -1 H 2 O 2 , 150 mg L -1 Fe(II) and pH 7.0), standard discharge (<0.5 mg L -1 in China) could be achieved, and the Fe(II) feeding time was found to be the limiting factor for the evolution of apparent kinetic rate constant in the second stage. Characterization studies showed that neutralization process after oxidation treatment favored the improvement of phosphorus removal due to the formation of more metal hydroxides. Moreover, as a comparison with lab-scale Fenton approach, the O 3 /H 2 O 2 ─Fe(II) oxidation process had more competitive advantages with respect to applicable pH range, removal efficiency, sludge production as well as economic costs. Copyright © 2017 Elsevier Ltd. All rights reserved.
6. Plasmonics-based detection of H(2) and CO: discrimination between reducing gases facilitated by material control.
Science.gov (United States)
Dharmalingam, Gnanaprakash; Joy, Nicholas A; Grisafe, Benjamin; Carpenter, Michael A
2012-01-01
Monitoring emissions in high-temperature-combustion applications is very important for regulating the discharge of gases such as NO(2) and CO as well as unburnt fuel into the environment. This work reports the detection of H(2) and CO gases by employing a metal-metal oxide nanocomposite (gold-yttria stabilized zirconia (Au-YSZ)) film fabricated through layer-by-layer physical vapor deposition (PVD). The change in the peak position of the localized surface plasmon resonance (LSPR) was monitored as a function of time and gas concentration. The responses of the films were preferential towards H(2), as observed from the results of exposing the films to the gases at temperatures of 500 °C in a background of dry air. Characterization of the samples by XRD and SEM enabled the correlation of material properties with the differences in the CO- and H(2)-induced LSPR peak shifts, including the relative desensitization towards NO(2). Sensing characteristics of films with varying support thicknesses and metal-particle diameters have been studied, and the results are presented. A comparison has been made to films fabricated through co-sputtered PVD, and the calibration curves of the sensing response show a preferential response towards H(2). The distinction between H(2) and CO responses is also seen through the use of principal-component analysis (PCA). Such material arrangements, which can be tuned for their selectivity by changing certain parameters such as particle size, support thickness, etc., have direct applications within optical chemical sensors for turbine engines, solid-oxide fuel cells, and other high-temperature applications.
7. Plasmonics-based detection of H2 and CO: discrimination between reducing gases facilitated by material control
Directory of Open Access Journals (Sweden)
Gnanaprakash Dharmalingam
2012-10-01
Full Text Available Monitoring emissions in high-temperature-combustion applications is very important for regulating the discharge of gases such as NO2 and CO as well as unburnt fuel into the environment. This work reports the detection of H2 and CO gases by employing a metal–metal oxide nanocomposite (gold–yttria stabilized zirconia (Au–YSZ film fabricated through layer-by-layer physical vapor deposition (PVD. The change in the peak position of the localized surface plasmon resonance (LSPR was monitored as a function of time and gas concentration. The responses of the films were preferential towards H2, as observed from the results of exposing the films to the gases at temperatures of 500 °C in a background of dry air. Characterization of the samples by XRD and SEM enabled the correlation of material properties with the differences in the CO- and H2-induced LSPR peak shifts, including the relative desensitization towards NO2. Sensing characteristics of films with varying support thicknesses and metal-particle diameters have been studied, and the results are presented. A comparison has been made to films fabricated through co-sputtered PVD, and the calibration curves of the sensing response show a preferential response towards H2. The distinction between H2 and CO responses is also seen through the use of principal-component analysis (PCA. Such material arrangements, which can be tuned for their selectivity by changing certain parameters such as particle size, support thickness, etc., have direct applications within optical chemical sensors for turbine engines, solid-oxide fuel cells, and other high-temperature applications.
8. Investigation of H2S separation from H2S/CH4 mixtures using functionalized and non-functionalized vertically aligned carbon nanotube membranes
Science.gov (United States)
2013-04-01
Separation of H2S from binary mixtures of H2S/CH4 using vertically aligned carbon nanotube membranes fabricated in anodic aluminum oxide (AAO) template was studied experimentally. Carbon nanotubes (CNTs) were grown in five AAO templates with different pore diameters using chemical vapor deposition, and CNT/AAO membranes with tubular carbon nanotube structure and open caps were selected for separation of H2S. For this, two tubular CNT/AAO membranes were fabricated with the CNT inner diameters of 23 and 8 nm. It was found that permeability and selectivity of the membrane with inner diameter of 23 nm for CNT were independent of upstream feed pressure and H2S feed concentration unlike that of CNT having an inner diameter of 8 nm. Selectivity of these membranes for separation of H2S was obtained in the ranges of 1.36-1.58 and 2.11-2.86, for CNTs with internal diameters of 23 and 8 nm, respectively. In order to enhance the separation of H2S from H2S/CH4 mixtures, dodecylamine was used to functionalize the CNT/AAO membrane with higher selectivity. The results showed that for amido-functionalized membrane, both upstream feed pressure and H2S partial pressure in the feed significantly increased H2S permeability, and selectivity for H2S being in the range of 3.0-5.57 respectively.
9. Promotion of H2 production by microwave-assisted treatment of water hyacinth with dilute H2SO4 through combined dark fermentation and photofermentation
International Nuclear Information System (INIS)
Cheng, Jun; Xia, Ao; Su, Huibo; Song, Wenlu; Zhou, Junhu; Cen, Kefa
2013-01-01
Highlights: • Water hyacinth is microwaved with dilute H 2 SO 4 to improve enzymatic hydrolysis. • Hydrolyzed hyacinth is fermented by hydrogenogens to improve dark H 2 yield. • Nearly 100% glucose and most arabinose in hydrolysate are used in dark fermentation. • H 2 yield from hyacinth via combined fermentation is 75.2% of theoretical H 2 yield. - Abstract: Water hyacinth was treated with microwave-assisted dilute H 2 SO 4 to improve saccharification before enzymatic hydrolysis and H 2 production during dark fermentation. A maximum reducing sugar (RS) yield of 64.4 g/100 g total volatile solid (TVS) (96.1% of the theoretical RS yield) was achieved when water hyacinth was treated through microwave heating with 1% dilute H 2 SO 4 for 15 min at 140 °C and then enzymatically hydrolyzed for 72 h. During enzymatic hydrolysis, glucose was efficiently produced from the hydrolysis of cellulose that resulted from the disruption of the lignocellulosic structure of water hyacinth after microwave-assisted H 2 SO 4 treatment. When the hydrolyzed water hyacinth was inoculated with H 2 -producing bacteria to produce H 2 during dark fermentation, a maximum H 2 yield of 112.3 ml/g TVS was obtained. The major sugar compositions in the residual solution from dark fermentation were xylose and cellobiose (total RS utilization efficiency: 88.5%). Through a combination of dark fermentation and photofermentation, the maximum H 2 yield from water hyacinth was significantly increased from 112.3 ml/g TVS to 751.5 ml/g TVS, which is 75.2% of the theoretical H 2 yield
10. Antibodies to H2a and H2b histones from the sera of HIV-infected patients catalyze site-specific degradation of these histones.
Science.gov (United States)
Baranova, Svetlana V; Dmitrienok, Pavel S; Ivanisenko, Nikita V; Buneva, Valentina N; Nevinsky, Georgy A
2017-06-01
Histones and their post-translational modifications have key roles in chromatin remodeling and gene transcription. Besides intranuclear functions, histones act as damage-associated molecules when they are released into the extracellular space. Administration of histones to animals leads to systemic inflammatory and toxic responses. Autoantibodies with enzymatic activities (abzymes) are distinctive features of some autoimmune and viral diseases. Electrophoretically homogeneous IgGs containing no canonical enzymes were isolated from the sera of HIV-infected patients by chromatography on several affinity sorbents including anti-histone Sepharose. In contrast to canonical proteases (trypsin, chymotrypsin, proteinase K), IgGs from HIV-infected patients specifically hydrolyzed only histones but not many other tested globular proteins. Using MALDI mass spectrometry the sites of H2a and H2b histone cleavage by anti-histone IgGs were determined for the first time. One cluster of H2a hydrolysis contains two major (↕) and four moderate (↓) cleavage sites: 31-H↓R↓L↓L↓R↕K G↕N-38. One major and two moderate sites of cleavage were revealed in the second cluster: 14-A↕KSRS↓SRA↓G-22. The third cluster corresponding to the H2a C-terminal part contains only five minor (†) sites of cleavage: 82-H†LQLAIRNDEELN†KLLG†RV†T†I-102. It was shown that two major and four moderate sites of cleavage were present in the main cluster of H2b hydrolysis: 46-K↕QvhpD↓TgiS↓SkA↓M↕GiM↓N-63. Two moderate sites of cleavage correspond to a relatively short 6-mer cluster: 12-K↓GskK↓A-17. The third relatively long 9-mer cluster contains one major and two minor sites of H2b cleavage: 80-L↕AHYN†KRS†T-88. In the nucleosome core particle, most of the major and moderate cleavage sites are located at the H2a/H2b interaction interface. Minor cleavage sites of H2a are involved in binding with H3 in the nucleosome core. Two moderate cleavage sites of H2b and one
11. Few-layered CoHPO4 · 3H2O ultrathin nanosheets for high performance of electrode materials for supercapacitors.
Science.gov (United States)
Pang, Huan; Wang, Shaomei; Shao, Weifang; Zhao, Shanshan; Yan, Bo; Li, Xinran; Li, Sujuan; Chen, Jing; Du, Weimin
2013-07-07
Ultrathin cobalt phosphate (CoHPO4 · 3H2O) nanosheets are successfully synthesized by a one pot hydrothermal method. Novel CoHPO4 · 3H2O ultrathin nanosheets are assembled for constructing the electrodes of supercapacitors. Benefiting from the nanostructures, the as-prepared electrode shows a specific capacitance of 413 F g(-1), and no obvious decay even after 3000 charge-discharge cycles. Such a quasi-two-dimensional material is a new kind of supercapacitor electrode material with high performance.
12. LiOH - H2O2 - H2O trinary system study for the selection of optimal conditions of lithium peroxide synthesis
International Nuclear Information System (INIS)
Nefedov, R A; Ferapontov, Yu A; Kozlova, N P
2016-01-01
Using solubility method the decay kinetics of peroxide products contained in liquid phase of LiOH - H 2 O 2 - H 2 O trinary system with 2 to 6% by wt hydrogen peroxide content in liquid phase in 21 to 33 °C temperature range has been studied. Conducted studies have allowed to determine temperature and concentration limits of solid phase existence of Li 2 O 2 ·H 2 O content, distinctness of which has been confirmed using chemical and qualitative X- ray phase analysis. Stabilizing effect of solid phase of Li 2 O 2 ·H 2 O content on hydrogen peroxide decay contained in liquid phase of LiOH - H 2 O 2 - H 2 O trinary system under conditions of experiments conducted has been shown. (paper)
13. LiOH - H2O2 - H2O trinary system study for the selection of optimal conditions of lithium peroxide synthesis
Science.gov (United States)
Nefedov, R. A.; Ferapontov, Yu A.; Kozlova, N. P.
2016-01-01
Using solubility method the decay kinetics of peroxide products contained in liquid phase of LiOH - H2O2 - H2O trinary system with 2 to 6% by wt hydrogen peroxide content in liquid phase in 21 to 33 °C temperature range has been studied. Conducted studies have allowed to determine temperature and concentration limits of solid phase existence of Li2O2·H2O content, distinctness of which has been confirmed using chemical and qualitative X- ray phase analysis. Stabilizing effect of solid phase of Li2O2·H2O content on hydrogen peroxide decay contained in liquid phase of LiOH - H2O2 - H2O trinary system under conditions of experiments conducted has been shown.
14. Study of ZrO2-H2SO4-(NH4)2SO4(NH4Cl)-H2O systems
International Nuclear Information System (INIS)
Motov, D.L.; Sozinova, Yu.P.; Rys'kina, M.P.
1988-01-01
Regions of formation, composition and solubility of ammonium sulfatozirconates (ASZ) in ZrO 2 -H 2 SO 4 -(NH 4 ) 2 SO 4 (NH 4 Cl)-H 2 O systems at 25 and 75 deg C are studied by the isothermal method. Five ASZ: (NH 4 ) 2 Zr(OH) 2 (SO 4 ) 2 , NH 4 ZrOH(SO 4 ) 2 xH 2 O, NH 4 ZrO 0.5 (OH) 2 SO 4 x1.5H 2 O, (NH 4 ) 2 Zr(SO 4 ) 3 x2H 2 O, (NH 4 ) 4 Zr(SO 4 ) 4 x4H 2 O are detected, their properties are investigated. Main sulfates are new compounds never described ealier
15. H2A-DUBbing the mammalian epigenome: expanding frontiers for histone H2A deubiquitinating enzymes in cell biology and physiology.
Science.gov (United States)
Belle, Jad I; Nijnik, Anastasia
2014-05-01
Posttranslational modifications of histone H2A through the attachment of ubiquitin or poly-ubiquitin conjugates are common in mammalian genomes and play an important role in the regulation of chromatin structure, gene expression, and DNA repair. Histone H2A deubiquitinases (H2A-DUBs) are a group of structurally diverse enzymes that catalyze the removal ubiquitin from histone H2A. In this review we provide a concise summary of the mechanisms that mediate histone H2A ubiquitination in mammalian cells, and review our current knowledge of mammalian H2A-DUBs, their biochemical activities, and recent developments in our understanding of their functions in mammalian physiology. Copyright © 2014 Elsevier Ltd. All rights reserved.
16. Removal of Organic Dyes from Industrial Wastewaters Using UV/H2O2, UV/H2O2/Fe (II, UV/H2O2/Fe (III Processes
Directory of Open Access Journals (Sweden)
2007-03-01
Full Text Available UV/H2O2, UV/H2O2/Fe (II and UV/H2O2/Fe (III processes are very effective in removing pollutants from wastewater and can be used for treatment of dyestuff units wastewaters. In this study, Rhodamine B was used as a typical organic dye. Rhodamine B has found wide applications in wax, leather, and paper industries. The results from this study showed that this dye was degradable in the presence of hydrogen peroxide under UV-C irradiation (30W mercury light and Photo-Fenton process. The dye was resistant to UV irradiation. In the absence of UV irradiation, the decolorization efficiency was very negligible in the presence of hydrogen. The effects of different system variables such as initial dye concentration, duration of UV irradiation, and initial hydrogen peroxide concentration were investigated in the UV/H2O2 process. Investigation of the kinetics of the UV/H2O2 process showed that the semi-log plot of the dye concentration versus time was linear, suggesting a first order reaction. It was found that Rhodamine B decolorization efficiencies in the UV/H2O2/Fe (II and UV/H2O2/Fe (III processes were higher than that in the UV/H2O2 process. Furthermore, a solution containing 20 ppm of Rhodamine B was decolorized in the presence 18 mM of H2O2 under UV irradiation for 15 minutes. It was also found that addition of 0.1 mM Fe(II or Fe(III to the solution containing 20 ppm of the dye and 5 mM H2O2 under UV light illumination decreased removal time to 10 min.
17. Conductivity And Thermal Stability of Solid Acid Composites CsH2PO4 /NaH2PO4/ SiO2
International Nuclear Information System (INIS)
2016-01-01
Solid acid composites CsH 2 PO 4 / NaH 2 PO 4 / SiO 2 with different mole ratios of CsH 2 PO 4 and NaH 2 PO 4 to SiO 2 were synthesized and characterized. Preliminary infrared measurements of CsH 2 PO 4 and its composites indicated that hydrogen bonds breaking and formation were detected between 1710 to 2710 cm -1 , while the rotation of phosphate tetrahedral anions occurred between 900 and 1200 cm -1 . The superprotonic transition of CsH 2 PO 4 / NaH 2 PO 4 / SiO 2 composite was identified at superprotonic temperatures between 230 and 260 degree Celcius, under atmospheric pressure. This study reveals higher conductivity values for composites with higher CsH 2 PO 4 (CDP) content. Solid acid composite CDP 613 appeared as the composite with the highest conductivity that is 7.2x10 -3 S cm -1 at 230 degree Celcius. Thermal stability of the solid acid composites such as temperature of dehydration, melting and decomposition were investigated. The addition of NaH 2 PO 4 lowers the dehydration temperature of the solid acid composites. (author)
18. Using H2O2 as oxidant in leaching of uranium ores. The new research on the reaction of H2O2 with Fe2+
International Nuclear Information System (INIS)
Gao Xizhen
1997-05-01
The new research on the reaction of H 2 O 2 with Fe 2+ has been studied. Through determining the electric potential, pH and O 2 release during the mutual titration between H 2 O 2 solution and FeSO 4 solution, deduced the chemical equations of H 2 O 2 (without free hydroxyl) oxidizing FeSO 4 and Fe 2 (SO 4 ) 3 oxidizing H 2 O 2 . The research results show that acid is a catalytic agent for decomposing H 2 O 2 to be O 2 and H 2 O besides iron ions. The maximum oxidizing potential is up to about 640 mV. While using H 2 O 2 as an oxidant in uranium heap leaching and in-situ leaching, controlling electric potential can be regarded as a method for adjusting the feeding speed of H 2 O 2 to keep the electric potential below 500 mV, thus the H 2 O 2 decomposition can be reduced. (13 refs., 3 tabs., 1 fig.)
19. Nucleosome acidic patch promotes RNF168- and RING1B/BMI1-dependent H2AX and H2A ubiquitination and DNA damage signaling.
Directory of Open Access Journals (Sweden)
Justin W Leung
2014-03-01
Full Text Available Histone ubiquitinations are critical for the activation of the DNA damage response (DDR. In particular, RNF168 and RING1B/BMI1 function in the DDR by ubiquitinating H2A/H2AX on Lys-13/15 and Lys-118/119, respectively. However, it remains to be defined how the ubiquitin pathway engages chromatin to provide regulation of ubiquitin targeting of specific histone residues. Here we identify the nucleosome acid patch as a critical chromatin mediator of H2A/H2AX ubiquitination (ub. The acidic patch is required for RNF168- and RING1B/BMI1-dependent H2A/H2AXub in vivo. The acidic patch functions within the nucleosome as nucleosomes containing a mutated acidic patch exhibit defective H2A/H2AXub by RNF168 and RING1B/BMI1 in vitro. Furthermore, direct perturbation of the nucleosome acidic patch in vivo by the expression of an engineered acidic patch interacting viral peptide, LANA, results in defective H2AXub and RNF168-dependent DNA damage responses including 53BP1 and BRCA1 recruitment to DNA damage. The acidic patch therefore is a critical nucleosome feature that may serve as a scaffold to integrate multiple ubiquitin signals on chromatin to compose selective ubiquitinations on histones for DNA damage signaling.
20. A neural network potential energy surface for the NaH2 system and dynamics studies on the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction.
Science.gov (United States)
Wang, Shufen; Yuan, Jiuchuang; Li, Huixing; Chen, Maodu
2017-08-02
In order to study the dynamics of the reaction H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), a new potential energy surface (PES) for the ground state of the NaH 2 system is constructed based on 35 730 ab initio energy points. Using basis sets of quadruple zeta quality, multireference configuration interaction calculations with Davidson correction were carried out to obtain the ab initio energy points. The neural network method is used to fit the PES, and the root mean square error is very small (0.00639 eV). The bond lengths, dissociation energies, zero-point energies and spectroscopic constants of H 2 (X 1 Σ g + ) and NaH(X 1 Σ + ) obtained on the new NaH 2 PES are in good agreement with the experiment data. On the new PES, the reactant coordinate-based time-dependent wave packet method is applied to study the reaction dynamics of H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), and the reaction probabilities, integral cross-sections (ICSs) and differential cross-sections (DCSs) are obtained. There is no threshold in the reaction due to the absence of an energy barrier on the minimum energy path. When the collision energy increases, the ICSs decrease from a high value at low collision energy. The DCS results show that the angular distribution of the product molecules tends to the forward direction. Compared with the LiH 2 system, the NaH 2 system has a larger mass and the PES has a larger well at the H-NaH configuration, which leads to a higher ICS value in the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction. Because the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction releases more energy, the product molecules can be excited to a higher vibrational state.
1. Submarine Ground Water Discharge and Fate Along the Coast of Kaloko-Honokohau National Historical Park, Hawai'i:Part 2, Spatial and Temporal Variations in Salinity, Radium-Isotope Activity, and Nutrient Concentrations in Coastal Waters, December 2003-April 2006
Science.gov (United States)
Knee, Karen; Street, Joseph; Grossman, Eric E.; Paytan, Adina
2008-01-01
The aquatic resources of Kaloko-Honokohau National Historical Park, including rocky shoreline, fishponds, and anchialine pools, provide habitat to numerous plant and animal species and offer recreational opportunities to local residents and tourists. A considerable amount of submarine groundwater discharge was known to occur in the park, and this discharge was suspected to influence the park's water quality. Thus, the goal of this study was to characterize spatial and temporal variations in the quality and quantity of groundwater discharge in the park. Samples were collected in December 2003, November 2005, and April 2006 from the coastal ocean, beach pits, three park observation wells, anchialine pools, fishponds, and Honokohau Harbor. The activities of two Ra isotopes commonly used as natural ground-water tracers (223Ra and 224Ra), salinity, and nutrient concentrations were measured. Fresh ground water composed a significant proportion (8-47 volume percent) of coastal-ocean water. This percentage varied widely between study sites, indicating significant spatial variation in submarine groundwater discharge at small (meter to kilometer) scales. Nitrate + nitrite, phosphate, and silica concentrations were significantly higher in nearshore coastal-ocean samples relative to samples collected 1 km or more offshore, and linear regression showed that most of this difference was due to fresh ground-water discharge. High-Ra-isotope-activity, higher-salinity springs were a secondary source of nutrients, particularly phosphate, at Honokohau Harbor and Aiopio Fishtrap. Salinity, Ra-isotope activity, and nutrient concentrations appeared to vary in response to the daily tidal cycle, although little seasonal variation was observed, indicating that submarine ground-water discharge may buffer the park's water quality against the severe seasonal changes that would occur in a system where freshwater inputs were dominated by rivers and runoff. Ra-isotope-activity ratios indicated
2. Spectroscopic diagnostics of the vibrational population in the ground state of H2 and D2 molecules
International Nuclear Information System (INIS)
Fantz, U.; Heger, B.
1998-01-01
A diagnostic method has been evaluated for measuring the relative vibrational ground-state population of molecular hydrogen and deuterium. It is based on the analysis of the diagonal Fulcher bands · 3 Π u →a 3 Σ g + ) and the Franck-Condon principle of excitation. The validity of the underlying assumptions was verified by experiments in microwave discharges and the method is recommended for application in divertor plasmas in controlled fusion experiments. By attributing a vibrational temperature T vib to the ground-state electronic level (X 1 Σ g + ) and assuming population via the Franck-Condon principle, the upper Fulcher state vibrational distribution can be derived theoretically with T vib as parameter. Comparison with experimentally derived upper-state population gives the corresponding T vib of the ground state. The Franck-Condon factors for the · 3 Π 1 Σ g + and · 3 Π u →a 3 Σ g + transitions have been calculated for both hydrogen and deuterium from molecular constants using the FCFRKR code. The method has been applied to low pressure H 2 /He and D 2 /He microwave plasmas, showing good agreement of experimentally and theoretically derived upper Fulcher state vibrational distributions. The vibrational temperatures range from 3200 K to 6800 K for H 2 and 2600 K to 4000 K for D 2 · depending on molecular density, pressure and electron temperature, but indicating nearly the same vibrational population for H 2 and D 2 for comparable plasma conditions. (author)
3. A role for H2S in the microcirculation of newborns: the major metabolite of H2S (thiosulphate is increased in preterm infants.
Directory of Open Access Journals (Sweden)
Rebecca M Dyson
Full Text Available Excessive vasodilatation during the perinatal period is associated with cardiorespiratory instability in preterm neonates. Little evidence of the mechanisms controlling microvascular tone during circulatory transition exists. We hypothesised that hydrogen sulphide (H2S, an important regulator of microvascular reactivity and central cardiac function in adults and animal models, may contribute to the vasodilatation observed in preterm newborns. Term and preterm neonates (24-43 weeks gestational age were studied. Peripheral microvascular blood flow was assessed by laser Doppler. Thiosulphate, a urinary metabolite of H2S, was determined by high performance liquid chromatography as a measure of 24 hr total body H2S turnover for the first 3 days of postnatal life. H2S turnover was greatest in very preterm infants and decreased with increasing gestational age (p = 0.0001. H2S turnover was stable across the first 72 hrs of life in older neonates. In very preterm neonates, H2S turnover increased significantly from day 1 to 3 (p =0.0001; and males had higher H2S turnover than females (p = 0.04. A significant relationship between microvascular blood flow and H2S turnover was observed on day 2 of postnatal life (p = 0.0004. H2S may play a role in maintaining microvascular tone in the perinatal period. Neonates at the greatest risk of microvascular dysfunction characterised by inappropriate peripheral vasodilatation--very preterm male neonates--are also the neonates with highest levels of total body H2S turnover suggesting that overproduction of this gasotransmitter may contribute to microvascular dysfunction in preterms. Potentially, H2S is a target to selectively control microvascular tone in the circulation of newborns.
4. I + (H2O)2 → HI + (H2O)OH Forward and Reverse Reactions. CCSD(T) Studies Including Spin-Orbit Coupling.
Science.gov (United States)
Wang, Hui; Li, Guoliang; Li, Qian-Shu; Xie, Yaoming; Schaefer, Henry F
2016-03-03
The potential energy profile for the atomic iodine plus water dimer reaction I + (H2O)2 → HI + (H2O)OH has been explored using the "Gold Standard" CCSD(T) method with quadruple-ζ correlation-consistent basis sets. The corresponding information for the reverse reaction HI + (H2O)OH → I + (H2O)2 is also derived. Both zero-point vibrational energies (ZPVEs) and spin-orbit (SO) coupling are considered, and these notably alter the classical energetics. On the basis of the CCSD(T)/cc-pVQZ-PP results, including ZPVE and SO coupling, the forward reaction is found to be endothermic by 47.4 kcal/mol, implying a significant exothermicity for the reverse reaction. The entrance complex I···(H2O)2 is bound by 1.8 kcal/mol, and this dissociation energy is significantly affected by SO coupling. The reaction barrier lies 45.1 kcal/mol higher than the reactants. The exit complex HI···(H2O)OH is bound by 3.0 kcal/mol relative to the asymptotic limit. At every level of theory, the reverse reaction HI + (H2O)OH → I + (H2O)2 proceeds without a barrier. Compared with the analogous water monomer reaction I + H2O → HI + OH, the additional water molecule reduces the relative energies of the entrance stationary point, transition state, and exit complex by 3-5 kcal/mol. The I + (H2O)2 reaction is related to the valence isoelectronic bromine and chlorine reactions but is distinctly different from the F + (H2O)2 system.
5. NK cell receptor/H2-Dk-dependent host resistance to viral infection is quantitatively modulated by H2q inhibitory signals.
Science.gov (United States)
Fodil-Cornu, Nassima; Loredo-Osti, J Concepción; Vidal, Silvia M
2011-04-01
The cytomegalovirus resistance locus Cmv3 has been linked to an epistatic interaction between two loci: a Natural Killer (NK) cell receptor gene and the major histocompatibility complex class I (MHC-I) locus. To demonstrate the interaction between Cmv3 and H2(k), we generated double congenic mice between MA/My and BALB.K mice and an F(2) cross between FVB/N (H-2(q)) and BALB.K (H2(k)) mice, two strains susceptible to mouse cytomegalovirus (MCMV). Only mice expressing H2(k) in conjunction with Cmv3(MA/My) or Cmv3(FVB) were resistant to MCMV infection. Subsequently, an F(3) cross was carried out between transgenic FVB/H2-D(k) and MHC-I deficient mice in which only the progeny expressing Cmv3(FVB) and a single H2-D(k) class-I molecule completely controlled MCMV viral loads. This phenotype was shown to be NK cell-dependent and associated with subsequent NK cell proliferation. Finally, we demonstrated that a number of H2(q) alleles influence the expression level of H2(q) molecules, but not intrinsic functional properties of NK cells; viral loads, however, were quantitatively proportional to the number of H2(q) alleles. Our results support a model in which H-2(q) molecules convey Ly49-dependent inhibitory signals that interfere with the action of H2-D(k) on NK cell activation against MCMV infection. Thus, the integration of activating and inhibitory signals emanating from various MHC-I/NK cell receptor interactions regulates NK cell-mediated control of viral load.
6. NK Cell Receptor/H2-Dk–Dependent Host Resistance to Viral Infection Is Quantitatively Modulated by H2 q Inhibitory Signals
Science.gov (United States)
Fodil-Cornu, Nassima; Loredo-Osti, J. Concepción; Vidal, Silvia M.
2011-01-01
The cytomegalovirus resistance locus Cmv3 has been linked to an epistatic interaction between two loci: a Natural Killer (NK) cell receptor gene and the major histocompatibility complex class I (MHC-I) locus. To demonstrate the interaction between Cmv3 and H2k, we generated double congenic mice between MA/My and BALB.K mice and an F2 cross between FVB/N (H-2q) and BALB.K (H2k) mice, two strains susceptible to mouse cytomegalovirus (MCMV). Only mice expressing H2k in conjunction with Cmv3MA/My or Cmv3FVB were resistant to MCMV infection. Subsequently, an F3 cross was carried out between transgenic FVB/H2-Dk and MHC-I deficient mice in which only the progeny expressing Cmv3FVB and a single H2-Dk class-I molecule completely controlled MCMV viral loads. This phenotype was shown to be NK cell–dependent and associated with subsequent NK cell proliferation. Finally, we demonstrated that a number of H2q alleles influence the expression level of H2q molecules, but not intrinsic functional properties of NK cells; viral loads, however, were quantitatively proportional to the number of H2q alleles. Our results support a model in which H-2q molecules convey Ly49-dependent inhibitory signals that interfere with the action of H2-Dk on NK cell activation against MCMV infection. Thus, the integration of activating and inhibitory signals emanating from various MHC-I/NK cell receptor interactions regulates NK cell–mediated control of viral load. PMID:21533075
7. Post-Translational Modifications of H2A Histone Variants and Their Role in Cancer
Directory of Open Access Journals (Sweden)
David Corujo
2018-02-01
Full Text Available Histone variants are chromatin components that replace replication-coupled histones in a fraction of nucleosomes and confer particular characteristics to chromatin. H2A variants represent the most numerous and diverse group among histone protein families. In the nucleosomal structure, H2A-H2B dimers can be removed and exchanged more easily than the stable H3-H4 core. The unstructured N-terminal histone tails of all histones, but also the C-terminal tails of H2A histones protrude out of the compact structure of the nucleosome core. These accessible tails are the preferential target sites for a large number of post-translational modifications (PTMs. While some PTMs are shared between replication-coupled H2A and H2A variants, many modifications are limited to a specific histone variant. The present review focuses on the H2A variants H2A.Z, H2A.X, and macroH2A, and summarizes their functions in chromatin and how these are linked to cancer development and progression. H2A.Z primarily acts as an oncogene and macroH2A and H2A.X as tumour suppressors. We further focus on the regulation by PTMs, which helps to understand a degree of context dependency.
8. The effect of host relaxation and dynamics on guest molecule dynamics in H2/tetrahydrofuranhydrate.
Science.gov (United States)
Peterson, Vanessa K; Shoko, Elvis; Kearley, Gordon J
2011-01-01
We use ab initio molecular dynamics simulations to obtain classically the effects of H2O cage motions on the potential-energy surface (PES) of encapsulated H2 in the H2/tetrahydrofuran-hydrate system. The significant differences between the PES for the H2 in rigid and flexible cages that we find will influence calculation of the quantum dynamics of the H2. Part of these differences arises from the relaxation of the H2O cage around the classical H2, with a second part arising from the coupling of both translational and rotational motions of H2 with the H20 cage. We find that isotopic substitution of 2H for 1H of the H2O cage affects the coupling, which has implications for experiments that require the use of 2H2O, including inelastic neutron scattering that uses 2H2O cages in order to focus on the H2 guest dynamics. Overall, this work emphasizes the importance of taking into account cage dynamics in any approach used to understand the dynamics of H2 guests in porous framework materials.
9. Effect of H2 addition on combustion characteristics of dimethyl ether jet diffusion flame
International Nuclear Information System (INIS)
Kang, Yinhu; Lu, Xiaofeng; Wang, Quanhai; Gan, Lu; Ji, Xuanyu; Wang, Hu; Guo, Qiang; Song, Decai; Ji, Pengyu
2015-01-01
10. Spectroscopic measurement of H(1S) and H2(v double-prime,J double-prime) in an H- ion source plasma
International Nuclear Information System (INIS)
Stutzin, G.C.
1990-08-01
Low pressure H 2 discharges have been used for some time as sources of H - ions. These discharges contain many different species of particles which interact with each other and with the walls of the discharge chamber. Models exist that predict the populations of the various species for given macroscopic discharge parameters. However, many of the cross sections and wall catalyzation coefficients are unknown or somewhat uncertain. Therefore, it is of interest to measure the populations of as many of these species as possible, in order to determine the validity of the models. These models predict that H - is created predominantly by the two-step process of vibrational excitation of hydrogen molecules followed by dissociative attachment of slow electrons to these vibrationally-excited hydrogen molecules. Many different collisional processes must be included in the models to explain the dependence of the various populations upon macroscopic parameters. This work presents results of spectroscopic measurements of the density and translational temperature of hydrogen atoms and of specific rotationally- and vibrationally-excited states of electronic ground-state H 2 , in a discharge optimized for H - production, as well as conventional measurements of the various charged species within the plasma. The spectroscopic measurements are performed directly by narrowband, single-photon absorption in the vacuum ultraviolet
11. Study of NaBH4 reaction with RhCl3·4H2O and H2PtCl6·6H2O in dimethylformamide
International Nuclear Information System (INIS)
Khain, V.S.; Val'kova, V.P.
1988-01-01
Data on study of NaBH 4 reactions with RhCl 3 x4H 2 O and H 2 PtCl 6 x6H 2 O in dimethylformamide, which is a good solvent of both complex hydride and compounds of platinum metals are presented. Rhodium (3) and platinum (4) reduction by sodium tetrahydridoborate in dimethylformamide proceeds quantitatively up to element state. Depositions of powder-like rhodium and platinum or their sols stable up to 8 months are formed depending on the ratio of concentrations of the reacting substances. Stoichiometry of redox-reactions is established based on spectrophotometric, gasovolumetric measurements,
12. Resonances in photoionization. Cross section for vibrationally excited H2
International Nuclear Information System (INIS)
Mezei, J.Zs.; Jungen, Ch.
2011-01-01
Complete text of publication follows. Diatomic molecular Hydrogen is the most abundant molecule in interstellar molecular clouds. The modeling of these environments relies on accurate cross sections for the various relevant processes. Among them, the photoionization plays a major role in the kinetics and in the energy exchanges involving H 2 . The recent discovery of vibrationally excited molecular hydrogen in extragalactic environments revealed the need for accurate evaluation of the corresponding photoionization cross sections. In the present work we report theoretical photoionization cross sections for excitation from excited vibrational levels of the ground state, dealing with the Q(N = 1) (ΔN = 0, where N is the total angular momentum of the molecule) transitions which account for roughly one third of the total photoabsorption cross section. We will focus on the v' = 1 excited level of the ground electronic state. Our calculations are based on Multichannel Quantum Defect Theory (MQDT), which allows us to take into account of the full manifold of Rydberg states and their interactions with the electronic continuum. We have carried out two types of MQDT calculations. First, we omitted all open channels and calculated energy levels, wave functions and spontaneous emission Einstein coefficients, making use of the theoretical method presented in [2]. In a second set of calculations we included the open ionization channels in the computations getting the continuum phase shifts, channel mixing coefficients and channel dipole moments and finally the photoabsorption/ photoionization cross section. The cross section is dominated by the presence of resonance structures corresponding to excitation of various vibrational levels of bound electronic states which lie above the ionization threshold. In order to assess the importance of the resonances we have calculated for each vibrational interval (the energy interval between two consecutive ionization thresholds) the
13. Ultra Low Air and H2 Permeability Cryogenic Bladder Materials for Inflatable Habitats, Phase I
Data.gov (United States)
National Aeronautics and Space Administration — NanoSonic has recently developed a hydrogen (H2) dispenser hose to realize H2 as a safe, reliable, and cost competitive replacement for gasoline. NanoSonic's...
14. Soil carbon content and relative abundance of high affinity H2-oxidizing bacteria predict atmospheric H2 soil uptake activity better than soil microbial community composition
NARCIS (Netherlands)
Khdhiri, Mondher; Hesse, Laura; Popa, Maria Elena; Quiza, Liliana; Lalonde, Isabelle; Meredith, Laura K.; Röckmann, Thomas; Constant, Philippe
2015-01-01
Soil-atmosphere exchange of H2 is controlled by gas diffusion and the microbial production and oxidation activities in soil. Among these parameters, the H2 oxidation activity catalyzed by soil microorganisms harboring high affinity hydrogenase is the most difficult variable to parameterize because
15. Decolorization and Mineralization of Reactive Dyes, by the H2O2/UV Process With Electrochemically Produced H2O2
NARCIS (Netherlands)
Jeric, T.; Bisselink, R.J.M.; Tongeren, W. van; Marechal. A.M. Le
2013-01-01
Decolorization of Reactive Red 238, Reactive Orange 16, Reactive Black 5 and Reactive Blue 4 was studied in the UV/H2O2 process with H2O2 being produced electrochemically. The experimental results show that decolorization increased considerably when switching on the electrochemical production of
16. Structural Insights into the Association of Hif1 with Histones H2A-H2B Dimer and H3-H4 Tetramer.
Science.gov (United States)
Zhang, Mengying; Liu, Hejun; Gao, Yongxiang; Zhu, Zhongliang; Chen, Zijun; Zheng, Peiyi; Xue, Lu; Li, Jixi; Teng, Maikun; Niu, Liwen
2016-10-04
Histone chaperones are critical for guiding specific post-transcriptional modifications of histones, safeguarding the histone deposition (or disassociation) of nucleosome (dis)assembly, and regulating chromatin structures to change gene activities. HAT1-interacting factor 1 (Hif1) has been reported to be an H3-H4 chaperone and to be involved in telomeric silencing and nucleosome (dis)assembly. However, the structural basis for the interaction of Hif1 with histones remains unknown. Here, we report the complex structure of Hif1 binding to H2A-H2B for uncovering the chaperone specificities of Hif1 on binding to both the H2A-H2B dimer and the H3-H4 tetramer. Our findings reveal that Hif1 interacts with the H2A-H2B dimer and the H3-H4 tetramer via distinct mechanisms, suggesting that Hif1 is a pivotal scaffold on alternate binding of H2A-H2B and H3-H4. These specificities are conserved features of the Sim3-Hif1-NASP interrupted tetratricopeptide repeat proteins, which provide clues for investigating their potential roles in nucleosome (dis)assembly. Copyright © 2016 Elsevier Ltd. All rights reserved.
17. Interannual observations and quantification of summertime H2O ice deposition on the Martian CO2 ice south polar cap
Science.gov (United States)
Brown, Adrian J.; Piqueux, Sylvain; Titus, Timothy N.
2014-01-01
The spectral signature of water ice was observed on Martian south polar cap in 2004 by the Observatoire pour l'Mineralogie, l'Eau les Glaces et l'Activite (OMEGA) ( Bibring et al., 2004). Three years later, the OMEGA instrument was used to discover water ice deposited during southern summer on the polar cap ( Langevin et al., 2007). However, temporal and spatial variations of these water ice signatures have remained unexplored, and the origins of these water deposits remains an important scientific question. To investigate this question, we have used observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the Mars Reconnaissance Orbiter (MRO) spacecraft of the southern cap during austral summer over four Martian years to search for variations in the amount of water ice. We report below that for each year we have observed the cap, the magnitude of the H2O ice signature on the southern cap has risen steadily throughout summer, particularly on the west end of the cap. The spatial extent of deposition is in disagreement with the current best simulations of deposition of water ice on the south polar cap (Montmessin et al., 2007). This increase in water ice signatures is most likely caused by deposition of atmospheric H2O ice and a set of unusual conditions makes the quantification of this transport flux using CRISM close to ideal. We calculate a ‘minimum apparent‘ amount of deposition corresponding to a thin H2O ice layer of 0.2 mm (with 70% porosity). This amount of H2O ice deposition is 0.6–6% of the total Martian atmospheric water budget. We compare our ‘minimum apparent’ quantification with previous estimates. This deposition process may also have implications for the formation and stability of the southern CO2 ice cap, and therefore play a significant role in the climate budget of modern day Mars.
18. Site specific comparison of H2, CH4 and compressed air energy storage in porous formations
Science.gov (United States)
Tilmann Pfeiffer, Wolf; Wang, Bo; Bauer, Sebastian
2016-04-01
The supply of energy from renewable sources like wind or solar power is subject to fluctuations determined by the climatic and weather conditions, and shortage periods can be expected on the order of days to weeks. Energy storage is thus required if renewable energy dominates the total energy production and has to compensate the shortages. Porous formations in the subsurface could provide large storage capacities for various energy carriers, such as hydrogen (H2), synthetic methane (CH4) or compressed air (CAES). All three energy storage options have similar requirements regarding the storage site characteristics and consequently compete for suitable subsurface structures. The aim of this work is to compare the individual storage methods for an individual storage site regarding the storage capacity as well as the achievable delivery rates. This objective is pursued using numerical simulation of the individual storage operations. In a first step, a synthetic anticline with a radius of 4 km, a drop of 900 m and a formation thickness of 20 m is used to compare the individual storage methods. The storage operations are carried out using -depending on the energy carrier- 5 to 13 wells placed in the top of the structure. A homogeneous parameter distribution is assumed with permeability, porosity and residual water saturation being 500 mD, 0.35 and 0.2, respectively. N2 is used as a cushion gas in the H2 storage simulations. In case of compressed air energy storage, a high discharge rate of 400 kg/s equating to 28.8 mio. m³/d at surface conditions is required to produce 320 MW of power. Using 13 wells the storage is capable of supplying the specified gas flow rate for a period of 31 hours. Two cases using 5 and 9 wells were simulated for both the H2 and the CH4 storage operation. The target withdrawal rates of 1 mio. sm³/d are maintained for the whole extraction period of one week in all simulations. However, the power output differs with the 5 well scenario producing
19. Study of a new direct current atmospheric pressure glow discharge in helium
International Nuclear Information System (INIS)
Gielniak, B.; Fiedler, T.; Broekaert, J.A.C.
2011-01-01
In this study a new DC-APGD operated in He was developed and characterized. The discharge is operated at 0.9 kV and about 25-35 mA and at a gas flow of 100 ml/min. The source was spectroscopically studied and parameters such as the rotational temperature (T rot ), the excitation temperature (T exc ), the ionization temperature (T ion ) and the electron number density (n e ) were determined. The current-voltage characteristic of the source was studied as well. At optimized conditions the discharge operates in the normal region of the current-voltage characteristic. Rotational and excitation temperatures determined with the use of OH band and Fe I lines as thermometric species were of the order of about 900-1200 and 4500-5500 K, respectively. This indicates that despite of the atmospheric pressure, the discharge is not in LTE. Spatially resolved temperature measurements were performed with axial as well as radial resolution and showed relatively flat profiles. Axially resolved emission intensity profiles for several species such as H, N 2 , N 2 + , OH, He and Hg were determined. It also was found that H 2 introduced into the He by electrolysis of acid solutions such as in ECHG considerably increases the spectroscopically measured gas temperatures but decreases the analyte line intensities, as shown for Hg.
20. The Cs2SO4-Ce2(SO4)3-H2SO4-H2O system at 150 and 200 deg C
International Nuclear Information System (INIS)
Bondar', S.A.; Belokoskov, V.I.; Trofimov, G.V.
1982-01-01
Solubility in the system Cs 2 SO 4 -Ce 2 (SO 4 ) 3 -H 2 SO 4 -H 2 O using the isothermal method at 150 and 200 deg C at molar ratios Cs 2 SO 4 :Ce 2 (SO 4 ) 3 =1:5 and conditions of sulfate crystallization Cs 2 SO 4 xCe 2 (SO 4 ) 3 , Ce 2 (SO 4 ) 3 x0.5H 2 SO 4 xnH 2 O (n=2-3) and Ce 2 (SO 4 ) 3 x3H 2 SO 4 are determined. Double sulfate Cs 2 SO 4 xCe 2 (SO 4 ) 3 is studied using the methods of crystallooptical, thermal, X-ray phase analyses and IR spectroscopy
1. Anomalous absorption in H2CN and CH2CN molecules
Indian Academy of Sciences (India)
Abstract. Structures of H2CN and CH2CN molecules are similar to that of H2CO mole- cule. The H2CO has shown anomalous absorption for its transition 111 − 110 at 4.8 GHz in a number of cool molecular clouds. Though the molecules H2CN and CH2CN have been identified in TMC-1 and Sgr B2 through some ...
2. Cavity ring down spectroscopy of CH, CH2, HCO, and H2CO in a premixed flat flame at both atmospheric and sub-atmospheric pressure
NARCIS (Netherlands)
Evertsen, R.; Staicu, A.D.; Oijen, van J.A.; Dam, N.J.; Goey, de L.P.H.; Meulen, ter J.J.; Cheauveau, C.; Vovelle, C.
2003-01-01
Density distributions of CH, CH2, HCO and H2CO have been measured in a premixed CH4/air flat flame by Cavity Ring Down Spectroscopy (CRDS). At atmospheric pressure problems are encountered due to the narrow spatial distribution of these species. Rotational flame Temperatures have been derived from
3. Exergetic and energetic comparison of LiCl-H_2O and LiBr-H_2O working pairs in a solar absorption cooling system
International Nuclear Information System (INIS)
Bellos, Evangelos; Tzivanidis, Christos; Antonopoulos, Kimon A.
2016-01-01
Highlights: • Two working pairs (LiCl-H_2O and LiBr-H_2O) are examined in a solar absorption chiller. • The examined single effect absorption chiller is driven by flat plate collectors. • The system is analyzed energetically and energetically for 3 ambient temperatures. • LiCl-H_2O performs better than LiBr-H_2O in all the examined cases. • The optimum operating temperature is lower for the case of pair LiCl-H_2O. - Abstract: The objective of this study is to investigate the use of an alternative working pair in a solar absorption cooling system. LiCl-H_2O is the new examined pair and it is compared energetically and exegetically with the conventional pair LiBr-H_2O, which is the most usual in air-conditioning applications. The simplest solar cooling system is analyzed in order to focus in the comparison between these working fluids. Specifically, flat plate collectors, coupled with a storage tank, feed the single effect absorption chiller which produces 250 kW cooling at 10 °C. The two pairs are examined parametrically for various heat source temperature levels and for three ambient temperature levels (25 °C, 30 °C and 35 °C). The minimization of the collecting area, which means maximum exergetic efficiency, is the optimization goal in every case. The final results show that LiCl-H_2O pair performs better in all cases by giving greater exergetic efficiency. More specifically, about 8% lower collecting area is required to cover the demanded cooling load with this working pair. Another interesting result is that the optimum heat source temperature for the LiCl-H_2O is roughly lower than the respective for the LiBr-H_2O. The system is analyzed in steady state with the commercial software Engineering Equator Solver (EES).
4. Reassessing the variability in atmospheric H2 using the two-way nested TM5 model
Energy Technology Data Exchange (ETDEWEB)
Pieterse, G.; Batenburg, A.M; Roeckmann, T. [Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht (Netherlands); Krol, M.C. [Department of Meteorology and Air Quality at Wageningen University, Wageningen (Netherlands); Brenninkmeijer, C.A.M. [Max-Planck-Institut fuer Chemie, Air Chemistry Division, Mainz (Germany); Popa, M.E.; Vermeulen, A.T. [Department of Air Quality and Climate Research at the Energy Research Centre of the Netherlands ECN, Petten (Netherlands); O' Doherty, S.; Grant, A. [School of Chemistry, University of Bristol, Bristol (United Kingdom); Steele, L.P.; Krummel, P.B.; Langenfelds, R.L. [Centre for Australian Weather and Climate Research, CSIRO Marine and Atmospheric Research, Aspendale, Victoria (Austria); Wang, H.J. [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA (United States); Schmidt, M.; Yver, C. [Laboratoire des Sciences du Climat et de l' Environnement (LSCE), Gif-sur-Yvette (France); Jordan, A. [Max-Planck Institut fuer Biogeochemie, Jena (Germany); Engel, A. [Institut fuer Meteorologie und Geophysik, Goethe-Universitaet Frankfurt, Frankfurt (Germany); Fisher, R.E.; Lowry, D.; Nisbet, E.G. [Department of Earth Sciences, Royal Holloway, University of London, Egham (United Kingdom); Reimann, S.; Vollmer, M.K.; Steinbacher, M. [Empa, Swiss Federal Institute for Materials Science and Technology, Laboratory for Air Pollution/Environmental Technology, Duebendorf (Switzerland); Hammer, S. [Institut fuer Umweltphysik, Heidelberg Universitaet, Heidelberg (Germany); Forster, G.; Sturges, W.T. [School of Environmental Sciences, University of East Anglia, Norwich (United Kingdom)
2013-05-16
This work reassesses the global atmospheric budget of H2 with the TM5 model. The recent adjustment of the calibration scale for H2 translates into a change in the tropospheric burden. Furthermore, the ECMWF Reanalysis-Interim (ERA-Interim) data from the European Centre for Medium-Range Weather Forecasts (ECMWF) used in this study show slower vertical transport than the operational data used before. Consequently, more H2 is removed by deposition. The deposition parametrization is updated because significant deposition fluxes for snow, water, and vegetation surfaces were calculated in our previous study. Timescales of 1-2h are asserted for the transport of H2 through the canopies of densely vegetated regions. The global scale variability of H2 and {rho}({Delta}H2) is well represented by the updated model. H2 is slightly overestimated in the Southern Hemisphere because too little H2 is removed by dry deposition to rainforests and savannahs. The variability in H2 over Europe is further investigated using a high-resolution model subdomain. It is shown that discrepancies between the model and the observations are mainly caused by the finite model resolution. The tropospheric burden is estimated at 165{+-}8 Tg H2. The removal rates of H2 by deposition and photochemical oxidation are estimated at 53{+-}4 and 23{+-}2 Tg H2/yr, resulting in a tropospheric lifetime of 2.2{+-}0.2 year.
5. File list: His.PSC.10.H2APERIODZac.AllCell [Chip-atlas[Archive
Lifescience Database Archive (English)
Full Text Available His.PSC.10.H2APERIODZac.AllCell mm9 Histone H2A.Zac Pluripotent stem cell SRX111870... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.PSC.10.H2APERIODZac.AllCell.bed ...
6. File list: His.PSC.05.H2APERIODZac.AllCell [Chip-atlas[Archive
Lifescience Database Archive (English)
Full Text Available His.PSC.05.H2APERIODZac.AllCell mm9 Histone H2A.Zac Pluripotent stem cell SRX111870... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.PSC.05.H2APERIODZac.AllCell.bed ...
7. Sampled-data and discrete-time H2 optimal control
NARCIS (Netherlands)
Trentelman, Harry L.; Stoorvogel, Anton A.
1993-01-01
This paper deals with the sampled-data H2 optimal control problem. Given a linear time-invariant continuous-time system, the problem of minimizing the H2 performance over all sampled-data controllers with a fixed sampling period can be reduced to a pure discrete-time H2 optimal control problem. This
8. Overview of the Hydrogen Financial Analysis Scenario Tool (H2FAST); NREL (National Renewable Energy Laboratory)
Energy Technology Data Exchange (ETDEWEB)
Melaina, Marc; Bush, Brian; Penev, Michael
2015-05-12
This presentation provides an introduction to the Hydrogen Financial Analysis Scenario Tool (H2FAST) and includes an overview of each of the three versions of H2FAST: the Web tool, the Excel spreadsheet version, and the beta version of the H2FAST Business Case Scenario tool.
9. Process for the production of heavy water by H2-methylamine isotopic exchange
International Nuclear Information System (INIS)
Briec, M.; Ravoire, J.; Rostaing, M.
1977-01-01
An isotopic exchange process for separating D 2 from H 2 is presented. The H 2 -monomethylamine system is studied on the laboratory scale (kinetics, H 2 solubility, thermal stability and solubility of the catalyst) and on the pilot plant scale (operating conditions and economics) [fr
10. 17 CFR 240.17h-2T - Risk assessment reporting requirements for brokers and dealers.
Science.gov (United States)
2010-04-01
... requirements for brokers and dealers. 240.17h-2T Section 240.17h-2T Commodity and Securities Exchanges... Organizations § 240.17h-2T Risk assessment reporting requirements for brokers and dealers. (a) Reporting requirements of risk assessment information required to be maintained by section 240.17h-1T. (1) Every broker...
11. A new H2+ source: Conceptual study and experimental test of an upgraded version of the VIS—Versatile ion source
Science.gov (United States)
Castro, G.; Torrisi, G.; Celona, L.; Mascali, D.; Neri, L.; Sorbello, G.; Leonardi, O.; Patti, G.; Castorina, G.; Gammino, S.
2016-08-01
The versatile ion source is an off-resonance microwave discharge ion source which produces a slightly overdense plasma at 2.45 GHz of pumping wave frequency extracting more than 60 mA proton beams and 50 mA He+ beams. DAEδALUS and IsoDAR experiments require high intensities for H2+ beams to be accelerated by high power cyclotrons for neutrinos generation. In order to fulfill the new requirements, a new plasma chamber and injection system has been designed and manufactured for increasing the H2+ beam intensity. In this paper the studies for the increasing of the H2+/p ratio and for the design of the new plasma chamber and injection system will be shown and discussed together with the experimental tests carried out at Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali del Sud (INFN-LNS) and at Best Cyclotron Systems test-bench in Vancouver, Canada.
12. Measurement of H and H2 populations in-situ in a low-temperature plasma by vacuum-ultraviolet laser-absorption spectroscopy
International Nuclear Information System (INIS)
Schlachter, A.S.; Young, A.T.; Stutzin, G.C.; Stearns, J.W.; Doebele, H.G.; Leung, K.N.; Kunkel, W.B.
1988-12-01
A new technique, vacuum-ultraviolet laser-absorption spectroscopy, has been developed to quantitatively determine the absolute density of H and H 2 within a plasma. The technique is particularly well suited to measurement in a plasma, where high charged particle and photon background complicate other methods of detection. The high selectivity and sensitivity of the technique allows for the measurement of the rotational-vibrational state distribution of H 2 as well as the translational temperature of the atoms and molecules. The technique has been used to study both pulsed and continuous H/sup /minus// ion-source plasma discharges. H 2 state distributions in a multicusp ''volume'' H/sup /minus// ion- source plasma show a high degree of internal excitation, with levels up to v = 5 and J = 8 being observed. The method is applicable for a very wide range of plasma conditions. Emission measurements from excited states of H are also reported. 17 refs., 9 figs
13. The system Ba(H2PO4)2-Sr(H2PO4)2-H3PO4(30%)-H2O at 25, 40 and 60 deg C
International Nuclear Information System (INIS)
Taranenko, N.P.; Serebrennikova, G.M.; Stepin, B.D.; Oboznenko, Yu.V.
1982-01-01
The system Ba(H 2 PO 4 ) 2 -Sr(H 2 PO 4 ) 2 -H 3 PO 4 (30%)-H 2 O (25 deg C) belongs to eutonic type systems. Solubility isotherms of salt components at 40 and 60 deg C are calculated. Polytherms (25-60 deg C) of solubility of monosubstituted barium and strontium phosphates in 30-60% H 3 PO 4 are obtained. The value of cocrystallization coefficient of Sr 2 + and Ba(H 2 PO 4 ) 2 Dsub(Sr)=0.042+-0.005 remains stable in the temperature range of 25-60 deg C and concentrations 30-60% phosphoric acid at initial content [Sr 2 + ]=1x10 - 2 mass%
14. Vessel Sewage Discharges
Science.gov (United States)
Vessel sewage discharges are regulated under Section 312 of the Clean Water Act, which is jointly implemented by the EPA and Coast Guard. This homepage links to information on marine sanitation devices and no discharge zones.
15. 75 FR 2879 - Identification of Foreign Countries Whose Nationals Are Eligible To Participate in the H-2A and H...
Science.gov (United States)
2010-01-19
... Countries Whose Nationals Are Eligible To Participate in the H-2A and H-2B Visa Programs AGENCY: Office of..., U.S. Citizenship and Immigration Services (USCIS) may only approve petitions for H-2A and H-2B... the H-2A and H-2B programs for the coming year. DATES: Effective Date: This notice is effective...
16. 78 FR 4154 - Identification of Foreign Countries Whose Nationals Are Eligible To Participate in the H-2A and H...
Science.gov (United States)
2013-01-18
... Whose Nationals Are Eligible To Participate in the H-2A and H-2B Nonimmigrant Worker Programs AGENCY...) regulations, U.S. Citizenship and Immigration Services (USCIS) may approve petitions for H-2A and H-2B... participate in the H-2A and H-2B programs for the coming year. The list published today includes one new...
17. Crystal structures of ZnCl2·2.5H2O, ZnCl2·3H2O and ZnCl2·4.5H2O
Directory of Open Access Journals (Sweden)
Erik Hennings
2014-12-01
Full Text Available The formation of different complexes in aqueous solutions is an important step in understanding the behavior of zinc chloride in water. The structure of concentrated ZnCl2 solutions is governed by coordination competition of Cl− and H2O around Zn2+. According to the solid–liquid phase diagram, the title compounds were crystallized below room temperature. The structure of ZnCl2·2.5H2O contains Zn2+ both in a tetrahedral coordination with Cl− and in an octahedral environment defined by five water molecules and one Cl− shared with the [ZnCl4]2− unit. Thus, these two different types of Zn2+ cations form isolated units with composition [Zn2Cl4(H2O5] (pentaaqua-μ-chlorido-trichloridodizinc. The trihydrate {hexaaquazinc tetrachloridozinc, [Zn(H2O6][ZnCl4]}, consists of three different Zn2+ cations, one of which is tetrahedrally coordinated by four Cl− anions. The two other Zn2+ cations are each located on an inversion centre and are octahedrally surrounded by water molecules. The [ZnCl4] tetrahedra and [Zn(H2O6] octahedra are arranged in alternating rows parallel to [001]. The structure of the 4.5-hydrate {hexaaquazinc tetrachloridozinc trihydrate, [Zn(H2O6][ZnCl4]·3H2O}, consists of isolated octahedral [Zn(H2O6] and tetrahedral [ZnCl4] units, as well as additional lattice water molecules. O—H...O hydrogen bonds between the water molecules as donor and ZnCl4 tetrahedra and water molecules as acceptor groups leads to the formation of a three-dimensional network in each of the three structures.
18. Competition between weak OH···π and CH··O hydrogen bonds: THz spectroscopy of the C2H2H2O and C2H4—H2O complexes
DEFF Research Database (Denmark)
Andersen, Jonas; Heimdal, Jimmy; Nelander, B.
2017-01-01
an intermolecular CH⋯O hydrogen-bonded configuration of C2v symmetry with the H2O subunit acting as the hydrogen bond acceptor. The observation and assignment of two large-amplitude donor OH librational modes of the C2H4—H2O complex at 255.0 and 187.5 cm−1, respectively, confirms an intermolecular OH⋯π hydrogen...
19. Generation of H2 and CO by solar thermochemical splitting of H2O and CO2 by employing metal oxides
International Nuclear Information System (INIS)
Rao, C.N.R.; Dey, Sunita
2016-01-01
Generation of H 2 and CO by splitting H 2 O and CO 2 respectively constitutes an important aspect of the present-day concerns with energy and environment. The solar thermochemical route making use of metal oxides is a viable means of accomplishing these reduction reactions. The method essentially involves reducing a metal oxide by heating and passing H 2 O or CO 2 over the nonstoichiometric oxide to cause reverse oxidation by abstracting oxygen from H 2 O or CO 2 . While ceria, perovskites and other oxides have been investigated for this purpose, recent studies have demonstrated the superior performance of perovskites of the type Ln 1−x A x Mn 1−y M y O 3 (Ln=rare earth, A=alkaline earth, M=various +2 and +3 metal ions), in the thermochemical generation of H 2 and CO. We present the important results obtained hitherto to point out how the alkaine earth and the Ln ions, specially the radius of the latter, determine the performance of the perovskites. The encouraging results obtained are exemplefied by Y 0.5 Sr 0.5 MnO 3 which releases 483 µmol/g of O 2 at 1673 K and produces 757 µmol/g of CO from CO 2 at 1173 K. The production of H 2 from H 2 O is also quite appreciable. Modification of the B site ion of the perovskite also affects the performance. In addition to perovskites, we present the generation of H 2 based on the Mn 3 O 4 /NaMnO 2 cycle briefly. - Graphical abstract: Ln 0.5 A 0.5 Mn 1−x M x O 3 (Ln=lanthanide; A=Ca, Sr; M=Al, Ga, Sc, Mg, Cr, Fe, Co) perovskites are employed for the two step thermochemical splitting of CO 2 and H 2 O for the generation of CO and H 2 . - Highlights: • Perovskite oxides based on Mn are ideal for the two-step thermochemical splitting of CO 2 and H 2 O. • In Ln 1−x A x MnO 3 perovskite (Ln=rare earth, A=alkaline earth) both Ln and A ions play major roles in the thermochemical process. • H 2 O splitting is also achieved by the use of the Mn 3 O 4 -sodium carbonate system. • Thermochemical splitting of CO 2 and H
20. Sub-Doppler slit jet infrared spectroscopy of astrochemically relevant cations: Symmetric (ν1) and antisymmetric (ν6) NH stretching modes in ND2H2+
Science.gov (United States)
Chang, Chih-Hsuan; Nesbitt, David J.
2018-01-01
Sub-Doppler infrared rovibrational transitions in the symmetric (v1) and antisymmetric (v6) NH stretch modes of the isotopomerically substituted ND2H2+ ammonium cation are reported for the first time in a slit jet discharge supersonic expansion spectrometer. The partially H/D substituted cation is generated by selective isotopic exchange of ND3 with H2O to form NHD2, followed by protonation with H3+ formed in the NHD2/H2/Ne slit-jet discharge expansion environment. Rotational assignment for ND2H2+ is confirmed rigorously by four line ground state combination differences, which agree to be within the sub-Doppler precision in the slit jet (˜9 MHz). Observation of both b-type (ν1) and c-type (ν6) bands enables high precision determination of the ground and vibrationally excited state rotational constants. From an asymmetric top Watson Hamiltonian analysis, the ground state constants are found to be A″ = 4.856 75(4) cm-1, B″ = 3.968 29(4) cm-1, and C″ = 3.446 67(6) cm-1, with band origins at 3297.5440(1) and 3337.9050(1) cm-1 for the v1 and v6 modes, respectively. This work permits prediction of precision microwave/mm-wave transitions, which should be invaluable in facilitating ongoing spectroscopic searches for partially deuterated ammonium cations in interstellar clouds and star-forming regions of the interstellar medium.
1. Few-layered CoHPO4.3H2O ultrathin nanosheets for high performance of electrode materials for supercapacitors
Science.gov (United States)
Pang, Huan; Wang, Shaomei; Shao, Weifang; Zhao, Shanshan; Yan, Bo; Li, Xinran; Li, Sujuan; Chen, Jing; Du, Weimin
2013-06-01
Ultrathin cobalt phosphate (CoHPO4.3H2O) nanosheets are successfully synthesized by a one pot hydrothermal method. Novel CoHPO4.3H2O ultrathin nanosheets are assembled for constructing the electrodes of supercapacitors. Benefiting from the nanostructures, the as-prepared electrode shows a specific capacitance of 413 F g-1, and no obvious decay even after 3000 charge-discharge cycles. Such a quasi-two-dimensional material is a new kind of supercapacitor electrode material with high performance.Ultrathin cobalt phosphate (CoHPO4.3H2O) nanosheets are successfully synthesized by a one pot hydrothermal method. Novel CoHPO4.3H2O ultrathin nanosheets are assembled for constructing the electrodes of supercapacitors. Benefiting from the nanostructures, the as-prepared electrode shows a specific capacitance of 413 F g-1, and no obvious decay even after 3000 charge-discharge cycles. Such a quasi-two-dimensional material is a new kind of supercapacitor electrode material with high performance. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01460f
2. Early discharge following birth
DEFF Research Database (Denmark)
Nilsson, Ingrid M. S.; Kronborg, Hanne; Knight, Christopher H.
2017-01-01
.26–0.48) and primiparous compared to multiparous had an OR of 0.22 (CI 0.17–0.29) for early discharge. Other predictors for early discharge were: no induction of labour, no epidural painkiller, bleeding less than 500 ml during delivery, higher gestational age, early expected discharge and positive breastfeeding experience...
3. Heart attack - discharge
Science.gov (United States)
... and lifestyle Cholesterol - drug treatment Controlling your high blood pressure Deep vein thrombosis - discharge Dietary fats explained Fast food tips Heart attack - discharge Heart attack - what to ask your doctor Heart bypass ... pacemaker - discharge High blood pressure - what to ask your doctor How to read ...
4. Methanogenic H2 syntrophy among thermophiles: a model of metabolism, adaptation and survival in the subsurface
Science.gov (United States)
Topcuoglu, B. D.; Stewart, L. C.; Butterfield, D. A.; Huber, J. A.; Holden, J. F.
2016-12-01
Approximately 1 giga ton (Gt, 1015 g) of CH4 is formed globally per year from H2, CO2 and acetate through methanogenesis, largely by methanogens growing in syntrophic association with anaerobic microbes that hydrolyze and ferment biopolymers. However, our understanding of methanogenesis in hydrothermal regions of the subseafloor and potential syntrophic methanogenesis at thermophilic temperatures (i.e., >50°C) is nascent. In this study, the growth of natural assemblages of thermophilic methanogens from Axial Seamount was primarily limited by H2 availability. Heterotrophs supported thermophilic methanogenesis by H2 syntrophy in microcosm incubations of hydrothermal fluids at 55°C and 80°C supplemented with tryptone only. Based on 16S rRNA gene sequencing, only heterotrophic archaea that produce H2, H2-consuming methanogens, and sulfate reducing archaea were found in 80°C tryptone microcosms from Marker 113 vent. No bacteria were found. In 55°C tryptone microcosms, sequences were found from H2-producing bacteria and H2-consuming methanogens and sulfate-reducing bacteria. In order to model the impact of H2 syntrophy at hyperthemophilic temperatures, a co-culture was established consisting of the H2-producing hyperthermophilic heterotroph Thermococcus paralvinellae and a H2-consuming hyperthermophilic methanogen Methanocaldococcus bathoardescens. When grown alone in a chemostat, the growth rates and steady-state cell concentrations of T. paralvinellae decreased significantly when a high H2 (70 µM) background was present. H2 inhibition was ameliorated by the production of formate, but in silico modeling suggests less energetic yield for the cells. H2 syntrophy relieved H2 inhibition for both the heterotroph and the methanogenic partners. The results demonstrate that thermophilic H2 syntrophy can support methanogenesis within natural microbial assemblages and may be an important alternative energy source for thermophilic autotrophs in marine geothermal environments.
5. D/H fractionation in the H2-H2O system at supercritical water conditions: Compositional and hydrogen bonding effects
Science.gov (United States)
Foustoukos, Dionysis I.; Mysen, Bjorn O.
2012-06-01
A series of experiments has been conducted in the H2-D2-D2O-H2O-Ti-TiO2 system at temperatures ranging from 300 to 800 °C and pressures between ∼0.3 and 1.3 GPa in a hydrothermal diamond anvil cell, utilizing Raman spectroscopy as a quantitative tool to explore the relative distribution of hydrogen and deuterium isotopologues of the H2 and H2O in supercritical fluids. In detail, H2O-D2O solutions (1:1) were reacted with Ti metal (3-9 h) in the diamond cell, leading to formation of H2, D2, HD, and HDO species through Ti oxidation and H-D isotope exchange reactions. Experimental results obtained in situ and at ambient conditions on quenched samples indicate significant differences from the theoretical estimates of the equilibrium thermodynamic properties of the H-D exchange reactions. In fact, the estimated enthalpy for the H2(aq)-D2(aq) disproportionation reaction (ΔHrxn) is about -3.4 kcal/mol, which differs greatly from the +0.16 kcal/mol predicted for the exchange reaction in the gas phase by statistical mechanics models. The exothermic behavior of the exchange reaction implies enhanced stability of H2 and D2 relative to HD. Accordingly, the significant energy difference of the internal H2(aq)-D2(aq)-HD(aq) equilibrium translates to strong differences of the fractionation effects between the H2O-H2 and D2O-D2 isotope exchange relationships. The D/H fractionation factors between H2O-H2(aq) and D2O-D2(aq) differ by 365‰ in the 600-800 °C temperature range, and are indicative of the greater effect of D2O contribution to the δD isotopic composition of supercritical fluids. The negative ΔHrxn values for the H2(aq)-D2(aq)-HD(aq) equilibrium and the apparent decrease of the equilibrium constant with increasing temperature might be because of differences of the Henry’s law constant between the H- and D-bearing species dissolved in supercritical aqueous solutions. Such effects may be attributed to the stronger hydrogen bonding in the O-H⋯O relative to the
6. H2O2 levels in rainwater collected in south Florida and the Bahama Islands
Science.gov (United States)
Zika, R.; Saltzman, E.; Chameides, W. L.; Davis, D. D.
1982-01-01
Measurements of H2O2 in rainwater collected in Miami, Florida, and the Bahama Islands area indicate the presence of H2O2 concentration levels ranging from 100,000 to 700,000 M. No systematic trends in H2O2 concentration were observed during an individual storm, in marked contrast to the behavior of other anions for example, NO3(-), SO4(-2), and Cl(-). The data suggest that a substantial fraction of the H2O2 found in precipitation is generated by aqueous-phase reactions within the cloudwater rather than via rainout and washout of gaseous H2O2.
7. New lanthanide hydrogen phosphites LnH (P03H)2 2H20
International Nuclear Information System (INIS)
Durand, J.; Tijani, N.; Cot, L.; Loukili, M.; Rafiq, M.
1988-01-01
LnH ((P0 3 H) 2 2H 2 0 is prepared from lanthanide oxide and phosphorous acid with Ln = La, Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er or Tm. By thermal gravimetric analysis LnH (P0 3 H) 2 and LnH 2 P 2 0 5 (P0 3 H) 2 are obtained. The three salts are orthorhombic. Parameters and space groups are given for the three salts of each lanthanide. 4 tabs., 13 refs
8. Homotopy Algorithm for Fixed Order Mixed H2/H(infinity) Design
Science.gov (United States)
Whorton, Mark; Buschek, Harald; Calise, Anthony J.
1996-01-01
Recent developments in the field of robust multivariable control have merged the theories of H-infinity and H-2 control. This mixed H-2/H-infinity compensator formulation allows design for nominal performance by H-2 norm minimization while guaranteeing robust stability to unstructured uncertainties by constraining the H-infinity norm. A key difficulty associated with mixed H-2/H-infinity compensation is compensator synthesis. A homotopy algorithm is presented for synthesis of fixed order mixed H-2/H-infinity compensators. Numerical results are presented for a four disk flexible structure to evaluate the efficiency of the algorithm.
9. Application of H2O2 and H2O2/Fe0 in removal of Acid Red 18 dye from aqueous solutions
Directory of Open Access Journals (Sweden)
Nazari Shahram
2013-08-01
Full Text Available Background & Aims of the Study: Organic dyes with a complex structure are often toxic, carcinogenic, mutagenic, non-biodegradation and stable in the environment and if released to the environment without treatment can endanger the environment and human health. The aim of this study was to evaluate the performance of H2O2 and H2O2/Fe0 Iron in removal of dye Acid Red 18 from aqueous solutions. Materials & Methods: This study was conducted at the laboratory scale. In this study, the removal efficiency of Acid Red 18 from a synthetic solution by H2O2 and H2O2/Fe0 was investigated. As well as Effect of solution pH, dye concentration, Concentration of Nanoscale Zero-Valent Iron, H2O2 and contact time in decolorization efficiency was investigated. Results: Results show that in pH=3, Contact time of 80 minutes, dye concentration of 50 mg/l and Concentration of Nanoscale Zero-Valent Iron of 2 g/l and H2O2 concentration equal to 200 mmol/l, the removal efficiency was about 98%. Conclusions: According to the results of experiments, H2O2/Fe0 has high efficiency in removal of Acid Red 18 from aqueous solution.
10. Profiling of cytosolic and mitochondrial H2O2 production using the H2O2-sensitive protein HyPer in LPS-induced microglia cells.
Science.gov (United States)
Park, Junghyung; Lee, Seunghoon; Lee, Hyun-Shik; Lee, Sang-Rae; Lee, Dong-Seok
2017-07-27
Dysregulation of the production of pro-inflammatory mediators in microglia exacerbates the pathologic process of neurodegenerative disease. ROS actively affect microglia activation by regulating transcription factors that control the expression of pro-inflammatory genes. However, accurate information regarding the function of ROS in different subcellular organelles has not yet been established. Here, we analyzed the pattern of cytosolic and mitochondrial H 2 O 2 formation in LPS-activated BV-2 microglia using the H 2 O 2- sensitive protein HyPer targeted to specific subcellular compartments. Our results show that from an early time, cytosolic H 2 O 2 started increasing constantly, whereas mitochondrial H 2 O 2 rapidly increased later. In addition, we found that MAPK affected cytosolic H 2 O 2 , but not mitochondrial H 2 O 2 . Consequently, our study provides the basic information about subcellular H 2 O 2 generation in activated microglia, and a useful tool for investigating molecular targets that can modulate neuroinflammatory responses. Copyright © 2017 Elsevier B.V. All rights reserved.
11. Polysulfides and products of H2S/S-nitrosoglutathione in comparison to H2S, glutathione and antioxidant Trolox are potent scavengers of superoxide anion radical and produce hydroxyl radical by decomposition of H2O2.
Science.gov (United States)
Misak, Anton; Grman, Marian; Bacova, Zuzana; Rezuchova, Ingeborg; Hudecova, Sona; Ondriasova, Elena; Krizanova, Olga; Brezova, Vlasta; Chovanec, Miroslav; Ondrias, Karol
2018-06-01
Exogenous and endogenously produced sulfide derivatives, such as H 2 S/HS - /S 2- , polysulfides and products of the H 2 S/S-nitrosoglutathione interaction (S/GSNO), affect numerous biological processes in which superoxide anion (O 2 - ) and hydroxyl (OH) radicals play an important role. Their cytoprotective-antioxidant and contrasting pro-oxidant-toxic effects have been reported. Therefore, the aim of our work was to contribute to resolving this apparent inconsistency by studying sulfide derivatives/free radical interactions and their consequent biological effects compared to the antioxidants glutathione (GSH) and Trolox. Using the electron paramagnetic resonance (EPR) spin trapping technique and O 2 - , we found that a polysulfide (Na 2 S 4 ) and S/GSNO were potent scavengers of O 2 - and cPTIO radicals compared to H 2 S (Na 2 S), GSH and Trolox, and S/GSNO scavenged the DEPMPO-OH radical. As detected by the EPR spectra of DEPMPO-OH, the formation of OH in physiological solution by S/GSNO was suggested. All the studied sulfide derivatives, but not Trolox or GSH, had a bell-shaped potency to decompose H 2 O 2 and produced OH in the following order: S/GSNO > Na 2 S 4 ≥ Na 2 S > GSH = Trolox = 0, but they scavenged OH at higher concentrations. In studies of the biological consequences of these sulfide derivatives/H 2 O 2 properties, we found the following: (i) S/GSNO alone and all sulfide derivatives in the presence of H 2 O 2 cleaved plasmid DNA; (ii) S/GSNO interfered with viral replication and consequently decreased the infectivity of viruses; (iii) the sulfide derivatives induced apoptosis in A2780 cells but inhibited apoptosis induced by H 2 O 2 ; and (iv) Na 2 S 4 modulated intracellular calcium in A87MG cells, which depended on the order of Na 2 S 4 /H 2 O 2 application. We suggest that the apparent inconsistency of the cytoprotective-antioxidant and contrasting pro-oxidant-toxic biological effects of sulfide derivatives results from their time
12. Poisoning of Ni-Based anode for proton conducting SOFC by H2S, CO2, and H2O as fuel contaminants
Science.gov (United States)
Sun, Shichen; Awadallah, Osama; Cheng, Zhe
2018-02-01
It is well known that conventional solid oxide fuel cells (SOFCs) based on oxide ion conducting electrolyte (e.g., yttria-stabilized zirconia, YSZ) and nickel (Ni) - ceramic cermet anodes are susceptible to poisoning by trace amount of hydrogen sulfide (H2S) while not significantly impacted by the presence of carbon dioxide (CO2) and moisture (H2O) in the fuel stream unless under extreme operating conditions. In comparison, the impacts of H2S, CO2, and H2O on proton-conducting SOFCs remain largely unexplored. This study aims at revealing the poisoning behaviors caused by H2S, CO2, and H2O for proton-conducting SOFCs. Anode-supported proton-conducting SOFCs with BaZe0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb) electrolyte and Ni-BZCYYb anode and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode as well as Ni-BZCYYb/BZCYYb/Ni-BZCYYb anode symmetrical cells were subjected to low ppm-level H2S or low percentage-level CO2 or H2O in the hydrogen fuel, and the responses in cell electrochemical behaviors were recorded. The results suggest that, contrary to conventional SOFCs that show sulfur poisoning and CO2 and H2O tolerance, such proton-conducting SOFCs with Ni-BZCYYb cermet anode seem to be poisoned by all three types of "contaminants". Beyond that, the implications of the experimental observations on understanding the fundamental mechanism of anode hydrogen electrochemical oxidation reaction in proton conducting SOFCs are also discussed.
13. Level of ubiquitinated histone H2B in chromatin is coupled to ongoing transcription
International Nuclear Information System (INIS)
Davie, J.R.; Murphy, L.C.
1990-01-01
The relationship between transcription and ubiquitination of the histones was investigated. Previous studies have shown that ubiquitinated (u) histone H2B and, to a lesser extend, mono- and polyubiquitinated histone H2A are enriched in transcriptionally active gene-enriched chromatin fractions. Here, the authors show that treatment of T-47D-5 human breast cancer cells with actinomycin D or 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole, inhibitors of heterogeneous nuclear RNA synthesis, selectively reduced the level of uH2B, but not uH2A, uH2A.Z, or polyubiquitinated H2A, in chromatin. Treatment of the cells with low levels of actinomycin D slightly reduced the level of uH2B, suggesting that inhibition of ribosomal RNA synthesis does not have a profound effect on the level of uH2B in chromatin. These results demonstrate that maintenance of the levels of uH2B in chromatin is dependent upon ongoing transcription, particularly the synthesis of hnRNA. Thus, histone H2B would be ubiquitinated when the nucleosome was opened during transcription. Ubiquitination of histone H2B may impede nucleosome refolding, facilitating subsequent rounds of transcription
14. Vibrational spectroscopy of NO + (H2O)n: Evidence for the intracluster reaction NO + (H2O)n --> H3O + (H2O)n - 2 (HONO) at n => 4
Science.gov (United States)
Choi, Jong-Ho; Kuwata, Keith T.; Haas, Bernd-Michael; Cao, Yibin; Johnson, Matthew S.; Okumura, Mitchio
1994-05-01
Infrared spectra of mass-selected clusters NO+(H2O)n for n=1 to 5 were recorded from 2700 to 3800 cm-1 by vibrational predissociation spectroscopy. Vibrational frequencies and intensities were also calculated for n=1 and 2 at the second-order Møller-Plesset (MP2) level, to aid in the interpretation of the spectra, and at the singles and doubles coupled cluster (CCSD) level energies of n=1 isomers were computed at the MP2 geometries. The smaller clusters (n=1 to 3) were complexes of H2O ligands bound to a nitrosonium ion NO+ core. They possessed perturbed H2O stretch bands and dissociated by loss of H2O. The H2O antisymmetric stretch was absent in n=1 and gradually increased in intensity with n. In the n=4 clusters, we found evidence for the beginning of a second solvation shell as well as the onset of an intracluster reaction that formed HONO. These clusters exhibited additional weak, broad bands between 3200 and 3400 cm-1 and two new minor photodissociation channels, loss of HONO and loss of two H2O molecules. The reaction appeared to go to completion within the n=5 clusters. The primary dissociation channel was loss of HONO, and seven vibrational bands were observed. From an analysis of the spectrum, we concluded that the n=5 cluster rearranged to form H3O+(H2O)3(HONO), i.e., an adduct of the reaction products.
15. H2A/K pseudogene mutation may promote cell proliferation
Energy Technology Data Exchange (ETDEWEB)
Guo, Jisheng; Jing, Ruirui; Lv, Xin; Wang, Xiaoyue; Li, Junqiang; Li, Lin; Li, Cuiling; Wang, Daoguang; Bi, Baibing; Chen, Xinjun [Cancer Research Center, Shandong University School of Medicine, Jinan 250012 (China); Yang, Jing-Hua, E-mail: sdu_crc_group1@126.com [Cancer Research Center, Shandong University School of Medicine, Jinan 250012 (China); Department of Surgery, VA Boston Healthcare System, Boston University School of Medicine, Boston 510660, MA (United States)
2016-05-15
Highlights: • The mutant H2A/K pseudogene is active. • The mutant H2A/K pseudogene can promote cell proliferation. - Abstract: Little attention has been paid to the histone H2A/K pseudogene. Results from our laboratory showed that 7 of 10 kidney cancer patients carried a mutant H2A/K pseudogene; therefore, we were interested in determining the relationship between mutant H2A/K and cell proliferation. We used shotgun and label-free proteomics methods to study whether mutant H2A/K lncRNAs affected cell proliferation. Quantitative proteomic analysis indicated that the expression of mutant H2A/K lncRNAs resulted in the upregulation of many oncogenes, which promoted cell proliferation. Further interaction analyses revealed that a proliferating cell nuclear antigen (PCNA)-protein interaction network, with PCNA in the center, contributes to cell proliferation in cells expressing the mutant H2A/K lncRNAs. Western blotting confirmed the critical upregulation of PCNA by mutant H2A/K lncRNA expression. Finally, the promotion of cell proliferation by mutant H2A/K lncRNAs (C290T, C228A and A45G) was confirmed using cell proliferation assays. Although we did not determine the exact mechanism by which the oncogenes were upregulated by the mutant H2A/K lncRNAs, we confirmed that the mutant H2A/K lncRNAs promoted cell proliferation by upregulating PCNA and other oncogenes. The hypothesis that cell proliferation is promoted by the mutant H2A/K lncRNAs was supported by the protein expression and cell proliferation assay results. Therefore, mutant H2A/K lncRNAs may be a new factor in renal carcinogenesis.
16. Factors affecting temporal H2S emission at construction and demolition (C&D) debris landfills.
Science.gov (United States)
Xu, Qiyong; Townsend, Timothy
2014-02-01
Odor problems associated with H2S emissions often result in odor complaints from nearby residents of C&D debris landfills, especially in the early morning. As part of a field study conducted on H2S removal ability using different cover materials, daily and seasonal H2S emissions through a soil cover layer were monitored at a C&D debris landfill to investigate factors affecting H2S emissions. H2S emission rates were not a constant, but varied seasonally, with an average emission rate of 4.67×10(-6)mgm(-2)s(-1). During a the 10-month field study, as the H2S concentration increased from 140ppm to about 3500ppm underneath the cover soil in the testing cell, H2S emissions ranged from zero to a maximum emission rate of 1.24×10(-5)mgm(-2)s(-1). Continuous emission monitoring indicated that H2S emissions even changed over time throughout the day, generally increasing from morning to afternoon, and were affected by soil moisture and temperature. Laboratory experiments were also conducted to investigate the effects of H2S concentration and cover soil moisture content on H2S emissions. The results showed that increased soil moisture reduced H2S emissions by retarding H2S migration through cover soil and dissolving H2S into soil water. The field study also indicated that due to atmospheric dispersion, high H2S emissions may not cause odor problems. Copyright © 2013 Elsevier Ltd. All rights reserved.
17. Differential regulation of TRPV1 channels by H2O2: implications for diabetic microvascular dysfunction
Science.gov (United States)
DelloStritto, Daniel J.; Connell, Patrick J.; Dick, Gregory M.; Fancher, Ibra S.; Klarich, Brittany; Fahmy, Joseph N.; Kang, Patrick T.; Chen, Yeong-Renn; Damron, Derek S.; Thodeti, Charles K.
2016-01-01
We demonstrated previously that TRPV1-dependent coupling of coronary blood flow (CBF) to metabolism is disrupted in diabetes. A critical amount of H2O2 contributes to CBF regulation; however, excessive H2O2 impairs responses. We sought to determine the extent to which differential regulation of TRPV1 by H2O2 modulates CBF and vascular reactivity in diabetes. We used contrast echocardiography to study TRPV1 knockout (V1KO), db/db diabetic, and wild type C57BKS/J (WT) mice. H2O2 dose-dependently increased CBF in WT mice, a response blocked by the TRPV1 antagonist SB366791. H2O2-induced vasodilation was significantly inhibited in db/db and V1KO mice. H2O2 caused robust SB366791-sensitive dilation in WT coronary microvessels; however, this response was attenuated in vessels from db/db and V1KO mice, suggesting H2O2-induced vasodilation occurs, in part, via TRPV1. Acute H2O2 exposure potentiated capsaicin-induced CBF responses and capsaicin-mediated vasodilation in WT mice, whereas prolonged luminal H2O2 exposure blunted capsaicin-induced vasodilation. Electrophysiology studies re-confirms acute H2O2 exposure activated TRPV1 in HEK293A and bovine aortic endothelial cells while establishing that H2O2 potentiate capsaicin-activated TRPV1 currents, whereas prolonged H2O2 exposure attenuated TRPV1 currents. Verification of H2O2-mediated activation of intrinsic TRPV1 specific currents were found in isolated mouse coronary endothelial cells from WT mice and decreased in endothelial cells from V1KO mice. These data suggest prolonged H2O2 exposure impairs TRPV1-dependent coronary vascular signaling. This may contribute to microvascular dysfunction and tissue perfusion deficits characteristic of diabetes. PMID:26907473
18. High-frequency underwater plasma discharge application in antibacterial activity
International Nuclear Information System (INIS)
Ahmed, M. W.; Choi, S.; Lyakhov, K.; Shaislamov, U.; Mongre, R. K.; Jeong, D. K.; Suresh, R.; Lee, H. J.
2017-01-01
Plasma discharge is a novel disinfection and effectual inactivation approach to treat microorganisms in aqueous systems. Inactivation of Gram-negative Escherichia coli (E. coli) by generating high-frequency, high-voltage, oxygen (O_2) injected and hydrogen peroxide (H_2O_2) added discharge in water was achieved. The effect of H_2O_2 dose and oxygen injection rate on electrical characteristics of discharge and E. coli disinfection has been reported. Microbial log reduction dependent on H_2O_2 addition with O_2 injection was observed. The time variation of the inactivation efficiency quantified by the log reduction of the initial E. coli population on the basis of optical density measurement was reported. The analysis of emission spectrum recorded after discharge occurrence illustrated the formation of oxidant species (OH"•, H, and O). Interestingly, the results demonstrated that O_2 injected and H_2O_2 added, underwater plasma discharge had fabulous impact on the E. coli sterilization. The oxygen injection notably reduced the voltage needed for generating breakdown in flowing water and escalated the power of discharge pulses. No impact of hydrogen peroxide addition on breakdown voltage was observed. A significant role of oxidant species in bacterial inactivation also has been identified. Furthermore the E. coli survivability in plasma treated water with oxygen injection and hydrogen peroxide addition drastically reduced to zero. The time course study also showed that the retardant effect on E. coli colony multiplication in plasma treated water was favorable, observed after long time. High-frequency underwater plasma discharge based biological applications is technically relevant and would act as baseline data for the development of novel antibacterial processing strategies.
19. Electron energy distribution function in SSM-discharge plasma
International Nuclear Information System (INIS)
Chernyak, V.Ya.; Olszewski, S.V.; Lebedev, D.O.; Evstigneev, M.A.
1996-01-01
The results of investigation in mass composition of positive component SSM-discharge plasma. All measurements were performed in H 2 and D 2 using the monopole mass-spectrometer MX 7301 and the probe technique. From the experimental dependences the value of H 3 + dissociation constant rate (k = 4 x 10 -11 cm -3 s -1 ) was estimated
20. Gibbs free energy of reactions involving SiC, Si3N4, H2, and H2O as a function of temperature and pressure
Science.gov (United States)
Isham, M. A.
1992-01-01
Silicon carbide and silicon nitride are considered for application as structural materials and coating in advanced propulsion systems including nuclear thermal. Three-dimensional Gibbs free energy were constructed for reactions involving these materials in H2 and H2/H2O. Free energy plots are functions of temperature and pressure. Calculations used the definition of Gibbs free energy where the spontaneity of reactions is calculated as a function of temperature and pressure. Silicon carbide decomposes to Si and CH4 in pure H2 and forms a SiO2 scale in a wet atmosphere. Silicon nitride remains stable under all conditions. There was no apparent difference in reaction thermodynamics between ideal and Van der Waals treatment of gaseous species.
1. Experimental study of cluster formation in binary mixture of H2O and H2SO4 vapors in the presence of an ionizing radiation source
Science.gov (United States)
Singh, J. J.; Smith, A. C.; Yue, G. K.
1980-01-01
Molecular clusters formed in pure nitrogen containing H2O and H2SO4 vapors and exposed to a 3 mCi Ni63 beta source were studied in the mass range 50 to 780 amu using a quadrupole mass spectrometer. Measurements were made under several combinations of relative humidity and relative acidity ranging from 0.7 to 7.5 percent and 0.00047 to 0.06333 percent, respectively. The number of H2SO4 molecules in the clusters observed ranged from 1 to 7 whereas the number of H2O molecules ranged from 1 to 16. The experimental cluster spectra differ considerably from those calculated using the classical nucleation theory. First order calculations using modified surface tension values and including the effects of multipole moments of the nucleating molecules indicate that these effects may be enough to explain the difference between the measured and the calculated spectra.
2. On the basic substances used in the separation process by isotope exchange H2S - H2O, at two temperatures, in view of producing heavy water
International Nuclear Information System (INIS)
Popescu, V.
1977-01-01
In view of producing heavy water, the influence of the deuterium proportion in the basic substances, on the efficiency of the isotope exchange process H 2 S - H 2 O for two temperatures was studied. Heavy water is extracted from ordinary water and concentrated from 0.014 per cent to 5-15 per cent D 2 O by isotope bithermal exchange with the hydrogen sulphite. Theoretical and experimental research was carried out in laboratories and then applied on a pilot plant by designing and testing a drying equipment for hydrogen sulphite. The maximum H 2 S concentration rose to 99.84 per cent. The purity of the hydrogen sulphite resulting from the pilot plant, as well as the optimization of the installation for producing H 2 S depending on the deuterium distribution, make sure that the two methods for the preparation of sodium sulphite and hydrogen sulphite can be applied in industry. (author)
3. Neutron scattering studies of the H2a-H2b and (H3-H4)/sub 2/ histone complexes
Energy Technology Data Exchange (ETDEWEB)
Carlson, R.D.
1982-01-01
Neutron scattering experiments have shown that both the (H3-H4)/sub 2/ and H2a-H2b histone complexes are quite asymmetric in solution. The (H3-H4)/sub 2/ tetramer is an oblate or flattened structure, with a radius of gyration almost as large as that of the core octamer. If the tetramer is primarily globular, it must have an axial ratio of about 1:5. It is more likely, however, that this asymmetry results in part from N-terminal arms that extend outward approximately within the major plane of the particle. If this is the case, less asymmetric models for the globular part of the tetramer, including a dislocated disk, can be made consistent with the scattering data. The H2a-H2b dimer, on the other hand, is an elongated structure. 48 references, 12 figures, 1 table.
4. Ab initio studies of O2-(H2O)n and O3-(H2O)n anionic molecular clusters, n≤12
DEFF Research Database (Denmark)
Bork, Nicolai Christian; Kurtén, T.; Enghoff, Martin Andreas Bødker
2011-01-01
that anionic O2−(H2O)n and O3−(H2O)n clusters are thermally stabilized at typical atmospheric conditions for at least n = 5. The first 4 water molecules are strongly bound to the anion due to delocalization of the excess charge while stabilization of more than 4 H2O is due to normal hydrogen bonding. Although...... clustering up to 12 H2O, we find that the O2 and O3 anions retain at least ca. 80 % of the charge and are located at the surface of the cluster. The O2− and O3− speicies are thus accessible for further reactions. Finally, the thermodynamics of a few relevant cluster reactions are considered....
5. Ab initio studies of O-2(-) (H2O)(n) and O-3(-) (H2O)(n) anionic molecular clusters, n
DEFF Research Database (Denmark)
Bork, Nicolai Christian; Kurten, T.; Enghoff, Martin Andreas Bødker
2011-01-01
that anionic O-2(-)(H2O)n and O-3(-)(H2O)n clusters are thermally stabilized at typical atmospheric conditions for at least n = 5. The first 4 water molecules are strongly bound to the anion due to delocalization of the excess charge while stabilization of more than 4 H2O is due to normal hydrogen bonding....... Although clustering up to 12 H2O, we find that the O-2 and O-3 anions retain at least ca. 80 % of the charge and are located at the surface of the cluster. The O-2(-) and O-3(-) speicies are thus accessible for further reactions. We consider the distributions of cluster sizes as function of altitude before...
6. An open-framework three-dimensional indium oxalate: [In(OH)(C2O4)(H2O)]3.H2O
International Nuclear Information System (INIS)
Yang Sihai; Li Guobao; Tian Shujian; Liao Fuhui; Lin Jianhua
2005-01-01
By hydrothermal reaction of In 2 O 3 with H 2 C 2 O 4 .2H 2 O in the presence of H 3 BO 3 at 155 deg. C, an open-framework three-dimensional indium oxalate of formula [In(OH)(C 2 O 4 )(H 2 O)] 3 .H 2 O (1) has been obtained. The compound crystallizes in the trigonal system, space group R3c with a=18.668(3)A, c=7.953(2)A, V=2400.3(7)A 3 , Z=6, R 1 =0.0352 at 298K. The small pores in 1 are filled with water molecules. It loses its filled water at about 180 deg. C without the change of structure, then the bounded water at 260 deg. C, and completely decompounds at 324 deg. C. The residue is confirmed to be In 2 O 3
7. Neutron scattering studies of the H2a-H2b and (H3-H4)2 histone complexes
International Nuclear Information System (INIS)
Carlson, R.D.
1982-01-01
Neutron scattering experiments have shown that both the (H3-H4) 2 and H2a-H2b histone complexes are quite asymmetric in solution. The (H3-H4) 2 tetramer is an oblate or flattened structure, with a radius of gyration almost as large as that of the core octamer. If the tetramer is primarily globular, it must have an axial ratio of about 1:5. It is more likely, however, that this asymmetry results in part from N-terminal arms that extend outward approximately within the major plane of the particle. If this is the case, less asymmetric models for the globular part of the tetramer, including a dislocated disk, can be made consistent with the scattering data. The H2a-H2b dimer, on the other hand, is an elongated structure. 48 references, 12 figures, 1 table
8. Molecular dynamics simulations of H2 adsorption in tetramethyl ammonium lithium phthalocyanine crystalline structures.
Science.gov (United States)
Lamonte, Kevin; Gómez Gualdrón, Diego A; Cabrales-Navarro, Fredy A; Scanlon, Lawrence G; Sandi, Giselle; Feld, William; Balbuena, Perla B
2008-12-11
Tetramethyl ammonium lithium phthalocyanine is explored as a potential material for storage of molecular hydrogen. Density functional theory calculations are used to investigate the molecular structure and the dimer conformation. Additional scans performed to determine the interactions of a H2 molecule located at various distances from the molecular sites are used to generate a simple force field including dipole-induced-dipole interactions. This force field is employed in molecular dynamics simulations to calculate adsorption isotherms at various pressures. The regions of strongest adsorption are quantified as functions of temperature, pressure, and separation between molecules in the adsorbent phase, and compared to the regions of strongest binding energy as given by the proposed force field. It is found that the total adsorption could not be predicted only from the spatial distribution of the strongest binding energies; the available volume is the other contributing factor even if the volume includes regions of much lower binding energy. The results suggest that the complex anion is primarily involved in the adsorption process with molecular hydrogen, whereas the cation serves to provide access for hydrogen adsorption in both sides of the anion molecular plane, and spacing between the planes.
9. Two new three-dimensional zinc phosphites templated by piperazine: [H2pip][Zn3(HPO3)4(H2O)2] and K[H2pip]0.5[Zn3(HPO3)4
Science.gov (United States)
Zhang, Xiao; Wang, Guo-Ming; Wang, Zong-Hua; Wang, Ying-Xia; Lin, Jian-Hua
2014-01-01
Two three-dimensional open-framework zinc phosphites with the same organically templated, [H2pip][Zn3(HPO3)4(H2O)2] (1) and K[H2pip]0.5[Zn3(HPO3)4] (2) (pip = piperazine), have been solvothermally synthesized and structurally characterized by IR, elemental analysis, thermogravimetric analysis, powder and single-crystal X-ray diffractions. Compound 1 consists of ZnO4 tetrahedra, [HPO3] pseudopyramids and [ZnO4(H2O)2] octahedra, which are linked through their vertexes to generate three-dimensional architecture with intersecting 8-membered channels along the [1 0 0], [0 0 1] and [1 0 1] directions. Compound 2 is constructed from strictly alternating ZnO4 tetrahedra and [HPO3] pseudopyramids, and exhibits (3,4)-connected inorganic framework with 8-, and 12-membered channels, in which the K+ and diprotonated H2pip2+ extra-framework cations reside, respectively. The coexistence of inorganic K+ and organic piperazine mixed templates in the structure is unique and, to the best of our knowledge, firstly observed in metal-phosphite materials. In addition, the participation of left-handed and right-handed helical chains in construction of the puckered 4.82 sheet structure in 2 is also noteworthy.
10. Crystal structure of strontium aqua(ethylenediaminetetraacetato)cobaltate(II) tetrahydrate Sr[CoEdta(H2O)] · 4H2O
International Nuclear Information System (INIS)
Zasurskaya, L.A.; Polynova, T.N.; Polyakova, I.N.; Sergienko, V.S.; Poznyak, A.L.
2001-01-01
The complex Sr[Co II Edta] · 5H 2 O (I) (where Edta 4- is the ethylenediaminetetraacetate ion) has been synthesized. The crystal structure of this compound is determined by X-ray diffraction. Crystals are monoclinic, a = 7.906(2) A, b = 12.768(2) A, c = 18.254(3) A, β = 95.30(3) deg., V 1834.8 A 3 , space group P2 1 /n, Z = 4, and R = 0.036. The structure is built up of the binuclear complex fragments {Sr(H 2 O) 3 [CoEdta(H 2 O)]}, which consist of the anionic [CoEdta(H 2 O)] 2- and cationic [Sr(H 2 O) 3 ] 2+ units linked by the Sr-O bonds into a three-dimensional framework. The coordination polyhedra of the Co and Sr atoms are mono- and bicapped trigonal prisms. The coordination sphere of the Co atom (the coordination number is equal to 6 + 1) involves six donor atoms (2N and 4O) of the Edta 4- ligand and the O w atom of water molecule. One of the Co-O distances (2.718 A) is considerably longer than the other Co-O lig distances (2.092-2.190 A) and the Co-O w (1) distance (2.079 A). The Sr coordination polyhedron (the coordination number is eight) contains three water molecules, three carbonyl O atoms of the three different anionic complexes, and two O atoms of one acetate group of the fourth anionic complex. The Sr-O distances fall in the range 2.535-2.674 A. The structural formula of the compound is {Sr(H 2 O) 3 [CoEdta(H 2 O)]} 3∞ · H 2 O
11. Characterization of a real time H2O2 monitor for use in studies on H2O2 production by antibodies and cells.
Science.gov (United States)
Sharma, Harish A; Balcavage, Walter X; Waite, Lee R; Johnson, Mary T; Nindl, Gabi
2003-01-01
It was recently shown that antibodies catalyze a reaction between water and ultraviolet light (UV) creating singlet oxygen and ultimately H2O2. Although the in vivo relevance of these antibody reactions is unclear, it is interesting that among a wide variety of non-antibody proteins tested, the T cell receptor is the only protein with similar capabilities. In clinical settings UV is believed to exert therapeutic effects by eliminating inflammatory epidermal T cells and we hypothesized that UV-triggered H2O2 production is involved in this process. To test the hypothesis we developed tools to study production of H2O2 by T cell receptors with the long-term goal of understanding, and improving, UV phototherapy. Here, we report the development of an inexpensive, real time H2O2 monitoring system having broad applicability. The detector is a Clark oxygen electrode (Pt, Ag/AgCl) modified to detect UV-driven H2O2 production. Modifications include painting the electrode black to minimize UV effects on the Ag/AgCl electrode and the use of hydrophilic, large pore Gelnots electrode membranes. Electrode current was converted to voltage and then amplified and recorded using a digital multimeter coupled to a PC. A reaction vessel with a quartz window was developed to maintain constant temperature while permitting UV irradiation of the samples. The sensitivity and specificity of the system and its use in cell-free and cell-based assays will be presented. In a cellfree system, production of H2O2 by CD3 antibodies was confirmed using our real time H2O2 monitoring method. Additionally we report the finding that splenocytes and Jurkat T cells also produce H2O2 when exposed to UV light.
12. Catalytic reduction of NOx with H2/CO/CH4 over PdMOR catalysts
International Nuclear Information System (INIS)
Pieterse, Johannis A.Z.; Booneveld, Saskia
2007-01-01
Conversion of NO x with reducing agents H 2 , CO and CH 4 , with and without O 2 , H 2 O, and CO 2 were studied with catalysts based on MOR zeolite loaded with palladium and cerium. The catalysts reached high NO x to N 2 conversion with H 2 and CO (>90% conversion and N 2 selectivity) range under lean conditions. The formation of N 2 O is absent in the presence of both H 2 and CO together with oxygen in the feed, which will be the case in lean engine exhaust. PdMOR shows synergic co-operation between H 2 and CO at 450-500 K. The positive effect of cerium is significant in the case of H 2 and CH 4 reducing agent but is less obvious with H 2 /CO mixture and under lean conditions. Cerium lowers the reducibility of Pd species in the zeolite micropores. The catalysts showed excellent stability at temperatures up to 673 K in a feed with 2500 ppm CH 4 , 500 ppm NO, 5% O 2 , 10% H 2 O (0-1% H 2 ), N 2 balance but deactivation is noticed at higher temperatures. Combining results of the present study with those of previous studies it shows that the PdMOR-based catalysts are good catalysts for NO x reduction with H 2 , CO, hydrocarbons, alcohols and aldehydes under lean conditions at temperatures up to 673 K. (author)
13. Effect of H2O2 on the corrosion behavior of 304L stainless steel
International Nuclear Information System (INIS)
Song, Taek Ho
1994-02-01
In connection with the safe storage of high level nuclear waste, effect of H 2 O 2 on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H 2 O 2 . The experimental results show that H 2 O 2 increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H 2 O 2 concentration increased, indicating that pitting resistance was decreased by the existence of H 2 O 2 in the electrolyte. These effects of H 2 O 2 on corrosion of 304L stainless steel are considered to be similar to those of γ-irradiation. To compare the effects of H 2 O 2 with those of O 2 , cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H 2 O 2 on the corrosion behavior were very similar to those of O 2 such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. Further, H 2 O 2 played much greater role in controlling cathodic reaction rate in neutral water environment. In acid and alkaline media, potential shifts by H 2 O 2 were restricted by the large current density of proton reduction and by the le Chatelier's principle respectively
14. Thermal Reactions of H2O2 on Icy Satellites and Small Bodies: Descent with Modification?
Science.gov (United States)
Hudson, Reggie L.; Loeffler, Mark J.
2012-01-01
Magnetospheric radiation drives surface and near-surface chemistry on Europa, but below a few meters Europa's chemistry is hidden from direct observation . As an example, surface radiation chemistry converts H2O and SO2 into H2O2 and (SO4)(sup 2-), respectively, and these species will be transported downward for possible thermally-driven reactions. However, while the infrared spectra and radiation chemistry of H2O2-containing ices are well documented, this molecule's thermally-induced solid-phase chemistry has seldom been studied. Here we report new results on thermal reactions in H2O + H2O2 + SO2 ices at 50 - 130 K. As an example of our results, we find that warming H2O + H2O2 + SO2 ices promotes SO2 oxidation to (SO4)(sup 2-). These results have implications for the survival of H2O2 as it descends, with modification, towards a subsurface ocean on Europa. We suspect that such redox chemistry may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto.
15. Effect of H-2 complex on the growth of embryo-derived teratomas in mice
International Nuclear Information System (INIS)
Taya, C.; Moriwaki, K.
1986-01-01
Seven-day-old embryos of several H-2 congenic strains were transplanted under the kidney capsules of syngeneic adult recipients to determine the genetic factors(s) governing the in vivo growth of embryo-derived teratomas. A.TH(H-2t2) and A.TL(H-2t1) strains showed significantly greater tumor weights than A.BY(H-2b) and A.SW(H-2s) strains. The A(H-2a) strain was intermediate in tumor size. A comparison of the genic constitution of the H-2 complex in each congenic strain suggested that the H-2D locus and/or its distal regions affected the growth of embryo-derived teratomas. The teratoma induced in the B10.A(H-2a) strain was smaller than that in the A(H-2a) strain, indicating that the genetic background of the A strain is favorable for teratoma growth. Histological observations demonstrated that the existence of embryonal carcinoma cells was necessary for the growth of teratomas. A radiation-sensitive immunological factor in the recipient probably plays a role in stimulating teratoma growth
16. Characterization of the UV-crosslinked heterodimer of histones H2B and H4
International Nuclear Information System (INIS)
Johnson, E.R.; Brown, D.M.; DeLange, R.J.
1986-01-01
At relatively high salt concentrations (1.2 M), histone 2B (H2B) and histone 4 (H4) can be covalently crosslinked by irradiation with ultraviolet light to yield a mixture of the three possible dimers: H2B-H2B, H4-H4, and H2B-H4. The formation of the H2B-H4 heterodimer was found to be favored at lower histone concentrations (> 90% H2B-H4 at 0.1 mg/ml total histone protein). CNBr cleavage of the H2B-H4 dimer produced three fragments which were separated by reverse phase HPLC. These fragments were identified by amino acid compositional analysis to be H4(85-102), H2B(62-125), and the crosslinked N-terminal regions H2B(1-59)-H4(1-84). Amino acid sequence analysis of the crosslinked fragment indicated that tyrosine-40 of H2B is likely involved in the covalent crosslinkage which joins the histone monomers to form the heterodimer
17. Sequence of cDNAs for mammalian H2A. Z, an evolutionarily diverged but highly conserved basal histone H2A isoprotein species
Energy Technology Data Exchange (ETDEWEB)
Hatch, C L; Bonner, W M
1988-02-11
The nucleotide sequences of cDNAs for the evolutionarily diverged but highly conserved basal H2A isoprotein, H2A.Z, have been determined for the rat, cow, and human. As a basal histone, H2A.Z is synthesized throughout the cell cycle at a constant rate, unlinked to DNA replication, and at a much lower rate in quiescent cells. Each of the cDNA isolates encodes the entire H2A.Z polypeptide. The human isolate is about 1.0 kilobases long. It contains a coding region of 387 nucleotides flanked by 106 nucleotides of 5'UTR and 376 nucleotides of 3'UTR, which contains a polyadenylation signal followed by a poly A tail. The bovine and rat cDNAs have 97 and 94% nucleotide positional identity to the human cDNA in the coding region and 98% in the proximal 376 nucleotides of the 3'UTR which includes the polyadenylation signal. A potential stem-forming sequence imbedded in a direct repeat is found centered at 261 nucleotides into the 3'UTR. Each of the cDNA clones could be transcribed and translated in vitro to yield H2A.Z protein. The mammalian H2A.Z cDNA coding sequences are approximately 80% similar to those in chicken and 75% to those in sea urchin.
18. Syntheses and Thermal Behaviors of Rb(FOX-7)·H2O and Cs(FOX-7)·H2O
International Nuclear Information System (INIS)
Luo, Jinan; Xu, Kangzhen; Wang, Min; Ren, Xiaolei; Chen, Yongshun; Song, Jirong; Zhao, Fengqi
2010-01-01
Two new energetic organic alkali metal salts, 1,1-diamino-2,2-dinitroethylene rubidium salt [Rb(FOX-7)·H 2 O] and 1,1- diamino-2,2-dinitroethylene cesium salt [Cs(FOX-7)·H 2 O], were synthesized by reacting of 1,1-diamino-2,2-dinitroethylene (FOX-7) and rubidium chloride or cesium chloride in alkali methanol aqueous solution, respectively. The thermal behaviors of Rb(FOX-7)·H 2 O and Cs(FOX-7)·H 2 O were studied with DSC and TG methods. The critical temperatures of thermal explosion of the two compounds are 216.22 and 223.73 .deg. C, respectively. Specific heat capacities of the two compounds were determined with a micro-DSC method, and the molar heat capacities are 217.46 and 199.47 J mol -1 K -1 at 298.15 K, respectively. The adiabatic times-to-explosion were also calculated to be a certain value of 5.81 - 6.36 s for Rb(FOX-7)·H 2 O, and 9.92 - 10.54 s for Cs(FOX-7)·H 2 O. After FOX-7 becoming alkali metal salts, thermal decomposition temperatures of the compounds heighten with the rise of element period, but thermal decomposition processes become intense
19. Impact of High Glucose and Proteasome Inhibitor MG132 on Histone H2A and H2B Ubiquitination in Rat Glomerular Mesangial Cells
Directory of Open Access Journals (Sweden)
Chenlin Gao
2013-01-01
Full Text Available Background. Hyperglycemia plays a pivotal role in the development of diabetic nephropathy (DN and may be related to epigenetic metabolic memory. One of the most crucial epigenetic mechanisms is histone modification, which is associated with the expression of a fibrosis factor in vascular injury. Aim .In this study, we investigated the ubiquitination of histones H2A and H2B to explore the epigenetic mechanisms of DN. Materials and Methods. The GMCs were cultured as follows: normal group, high glucose group, mannitol group, and intervention group. After 12 hr, 24 hr, and 48 hr, histones ubiquitination, transforming growth factor-β (TGF-β, and fibronectin (FN were measured using WB, RT-PCR, and IF. Result. High glucose can induce the upregulation of FN. H2A ubiquitination in GMCs increased in high glucose group (P<0.01, whereas it decreased significantly in intervention group (P<0.05. In contrast, H2B ubiquitination decreased with an increasing concentration of glucose, but it was recovered in the intervention group (P<0.05. Expression of TGF-β changed in response to abnormal histone ubiquitination. Conclusions. The high glucose may induce H2A ubiquitination and reduce H2B ubiquitination in GMCs. The changes of histone ubiquitination may be due in part to DN by activating TGF-β signaling pathway.
20. Rate constant for the H˙ + H2O → ˙OH + H2 reaction at elevated temperatures measured by pulse radiolysis.
Science.gov (United States)
Muroya, Y; Yamashita, S; Lertnaisat, P; Sanguanmith, S; Meesungnoen, J; Jay-Gerin, J-P; Katsumura, Y
2017-11-22
Maintaining the structural integrity of materials in nuclear power plants is an essential issue associated with safe operation. Hydrogen (H 2 ) addition or injection to coolants is a powerful technique that has been widely applied such that the reducing conditions in the coolant water avoid corrosion and stress corrosion cracking (SCC). Because the radiation-induced reaction of ˙OH + H 2 → H˙ + H 2 O plays a crucial role in these systems, the rate constant has been measured at operation temperatures of the reactors (285-300 °C) by pulse radiolysis, generating sufficient data for analysis. The reverse reaction H˙ + H 2 O → ˙OH + H 2 is negligibly slow at ambient temperature; however, it accelerates considerably quickly at elevated temperatures. Although the reverse reaction reduces the effectiveness of H 2 addition, reliable rate constants have not yet been measured. In this study, the rate constants have been determined in a temperature range of 250-350 °C by pulse radiolysis in an aqueous I - solution.
1. Measurements of the Activity of dissolved H2O in an Andesite Melt
Science.gov (United States)
Moore, G. M.; Touran, J. P.; Pu, X.; Kelley, K. A.; Cottrell, E.; Ghiorso, M. S.
2016-12-01
The large effect of dissolved H2O on the physical and chemical nature of silicate melts, and its role in driving volcanism, is well known and underscores the importance of this volatile component. A complete understanding of the chemical behavior of dissolved H2O in silicate melts requires the quantification of its thermodynamic activity as a function of pressure, temperature, and melt composition, particularly at low H2O contents (i.e. at under-saturated conditions). Knowledge of the activity of H2O in silicate melts at H2O-undersaturated conditions will improve our understanding of hydrous phase equilibria, as well as our models of physical melt properties. Measurement of the activity of any silicate melt component, much less that of a volatile component such as H2O, is a difficult experimental task however. By using a modified double capsule design (Matjuschkin et al, 2015) to control oxygen fugacity in piston cylinder experiments, along with high precision X-ray absorption techniques (XANES) to measure iron oxidation state in silicate glasses (Cottrell et al, 2009), we are able to constrain the H2O activity in silicate melts at under-saturated conditions. Preliminary results on an andesite melt with low H2O content (3 wt%) have been shown (Moore et al, 2016) to match predicted H2O activity values calculated using the H2O equation of state of Duan and Zhang (1996) and the H2O solubility model of Ghiorso and Gualda (2015). More recent results on the same andesite melt containing approximately 5 wt% H2O however show a large negative deviation from the predicted values. Reversal experiments involving an oxidized starting material are ongoing, as well as further characterization of the samples to detect the presence of possible contaminants that would induce reduction of the melt beyond that related to the H2O activity (e.g. graphite contamination).
2. The Role of Peroxiredoxins in the Transduction of H2O2 Signals.
Science.gov (United States)
Rhee, Sue Goo; Woo, Hyun Ae; Kang, Dongmin
2018-03-01
Hydrogen peroxide (H 2 O 2 ) is produced on stimulation of many cell surface receptors and serves as an intracellular messenger in the regulation of diverse physiological events, mostly by oxidizing cysteine residues of effector proteins. Mammalian cells express multiple H 2 O 2 -eliminating enzymes, including catalase, glutathione peroxidase (GPx), and peroxiredoxin (Prx). A conserved cysteine in Prx family members is the site of oxidation by H 2 O 2 . Peroxiredoxins possess a high-affinity binding site for H 2 O 2 that is lacking in catalase and GPx and which renders the catalytic cysteine highly susceptible to oxidation, with a rate constant several orders of magnitude greater than that for oxidation of cysteine in most H 2 O 2 effector proteins. Moreover, Prxs are abundant and present in all subcellular compartments. The cysteines of most H 2 O 2 effectors are therefore at a competitive disadvantage for reaction with H 2 O 2 . Recent Advances: Here we review intracellular sources of H 2 O 2 as well as H 2 O 2 target proteins classified according to biochemical and cellular function. We then highlight two strategies implemented by cells to overcome the kinetic disadvantage of most target proteins with regard to H 2 O 2 -mediated oxidation: transient inactivation of local Prx molecules via phosphorylation, and indirect oxidation of target cysteines via oxidized Prx. Critical Issues and Future Directions: Recent studies suggest that only a small fraction of the total pools of Prxs and H 2 O 2 effector proteins localized in specific subcellular compartments participates in H 2 O 2 signaling. Development of sensitive tools to selectively detect phosphorylated Prxs and oxidized effector proteins is needed to provide further insight into H 2 O 2 signaling. Antioxid. Redox Signal. 28, 537-557.
3. Histone H2AX is a critical factor for cellular protection against DNA alkylating agents.
Science.gov (United States)
Meador, J A; Zhao, M; Su, Y; Narayan, G; Geard, C R; Balajee, A S
2008-09-25
Histone H2A variant H2AX is a dose-dependent suppressor of oncogenic chromosome translocations. H2AX participates in DNA double-strand break repair, but its role in other DNA repair pathways is not known. In this study, role of H2AX in cellular response to alkylation DNA damage was investigated. Cellular sensitivity to two monofunctional alkylating agents (methyl methane sulfonate and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)) was dependent on H2AX dosage, and H2AX null cells were more sensitive than heterozygous cells. In contrast to wild-type cells, H2AX-deficient cells displayed extensive apoptotic death due to a lack of cell-cycle arrest at G(2)/M phase. Lack of G(2)/M checkpoint in H2AX null cells correlated well with increased mitotic irregularities involving anaphase bridges and gross chromosomal instability. Observation of elevated poly(ADP) ribose polymerase 1 (PARP-1) cleavage suggests that MNNG-induced apoptosis occurs by PARP-1-dependent manner in H2AX-deficient cells. Consistent with this, increased activities of PARP and poly(ADP) ribose (PAR) polymer synthesis were detected in both H2AX heterozygous and null cells. Further, we demonstrate that the increased PAR synthesis and apoptotic death induced by MNNG in H2AX-deficient cells are due to impaired activation of mitogen-activated protein kinase pathway. Collectively, our novel study demonstrates that H2AX, similar to PARP-1, confers cellular protection against alkylation-induced DNA damage. Therefore, targeting either PARP-1 or histone H2AX may provide an effective way of maximizing the chemotherapeutic value of alkylating agents for cancer treatment.
4. Combined treatment of hydroxypropyl guar gum in oilfield fracturing wastewater by coagulation and the UV/H2O2/ferrioxalate complexes process.
Science.gov (United States)
Zhang, Zhenchao
2018-02-01
Hydroxypropyl guar gum is considered to be a main component of oilfield fracturing wastewater (OFW). This work is intended to optimize the experimental conditions for the maximum oxidative degradation of hydroxypropyl guar gum by the coagulation and UV/H 2 O 2 /ferrioxalate complexes process. Optimal reaction conditions were proposed based on the chemical oxygen demand (COD) removal efficiency and UV _ vis spectra analysis. The overall removal efficiency of COD reached 83.8% for a dilution ratio of raw wastewater of 1:2, pH of 4 and FeCl 3 loading of 1,000 mg/L in the coagulation process; the dosage of H 2 O 2 (30%,v/v) was 0.6% (v/v) and added in three steps, the n(H 2 O 2 )/n(Fe 2+ ) was 2:1, n(Fe 2+ )/n(C 2 O 4 2- ) was 3:1 and pH was 4 in the UV/H 2 O 2 /ferrioxalate complexes process; pH was adjusted to 8.5-9 by NaOH and then cationic polyacrylamide (CPAM) of 2 mg/L was added in the neutralization and flocculation process. The decrease in COD during the coagulation process reduced the required H 2 O 2 dosage and improved efficiency in the subsequent UV/H 2 O 2 /ferrioxalate complexes process. Furthermore, COD removal efficiency significantly increased by more than 13.4% with the introduction of oxalate compared with UV/Fenton. The UV _ vis spectra analysis results indicated that the coagulation and UV/H 2 O 2 /ferrioxalate complexes process could efficiently remove the hydroxypropyl guar gum dissolved in OFW. An optimal combination of these parameters produced treated wastewater that met the GB8978-1996 Integrated Wastewater Discharge Standard level III emission standard.
5. Combined treatment of organic material in oilfield fracturing wastewater by coagulation and UV/H2O2/ferrioxalate complexes process.
Science.gov (United States)
Ge, Dan
2018-02-01
Organic material is considered to be a main component of oilfield fracturing wastewater (OFW). This work is intended to optimize the experimental conditions for the maximum oxidative degradation of organic material by coagulation and the UV/H 2 O 2 /ferrioxalate complexes process. Optimal reaction conditions are proposed based on the chemical oxygen demand (COD) removal efficiency. The overall removal efficiency of COD reached 83.8% when the dilution ratio of raw wastewater was 1:2, the pH was 4 and the FeCl 3 loading was 1,000 mg/L in the coagulation process; the dosage of H 2 O 2 (30%,v/v) was 0.6% (v/v) and added in three steps, the n(H 2 O 2 )/n(Fe 2+ ) was 2:1, n(Fe 2+ )/n(C 2 O 4 2- ) was 3:1 and the pH was 4 in the UV/H 2 O 2 /ferrioxalate complexes process; the pH was adjusted to 8.5-9 with NaOH and then 2 mg/L of cationic polyacrylamide (CPAM) was added in the neutralization and flocculation process. The decrease in COD during the coagulation process reduced the required H 2 O 2 dosage and improve efficiency in the subsequent UV/H 2 O 2 /ferrioxalate complexes process. Furthermore, there was a significant increase of 13.4% in the COD removal efficiency with the introduction of oxalate compared with UV/Fenton. Experimental results show that the coagulation and UV/H 2 O 2 /ferrioxalate complexes process could efficiently remove the organic material dissolved in OFW. An optimal combination of these parameters produced treated wastewater that met the GB8978-1996' Integrated Wastewater Discharge Standard' level III emission standard.
6. Crystal structures of hydrates of simple inorganic salts. III. Water-rich aluminium halide hydrates: AlCl3 · 15H2O, AlBr3 · 15H2O, AlI3 · 15H2O, AlI3 · 17H2O and AlBr3 · 9H2O.
Science.gov (United States)
Schmidt, Horst; Hennings, Erik; Voigt, Wolfgang
2014-09-01
Water-rich aluminium halide hydrate structures are not known in the literature. The highest known water content per Al atom is nine for the perchlorate and fluoride. The nonahydrate of aluminium bromide, stable pentadecahydrates of aluminium chloride, bromide and iodide, and a metastable heptadecahydrate of the iodide have now been crystallized from low-temperature solutions. The structures of these hydrates were determined and are discussed in terms of the development of cation hydration spheres. The pentadecahydrate of the chloride and bromide are isostructural. In AlI(3) · 15H2O, half of the Al(3+) cations are surrounded by two complete hydration spheres, with six H2O in the primary and 12 in the secondary. For the heptadecahydrate of aluminium iodide, this hydration was found for every Al(3+).
7. Properties of water surface discharge at different pulse repetition rates
International Nuclear Information System (INIS)
Ruma,; Yoshihara, K.; Hosseini, S. H. R.; Sakugawa, T.; Akiyama, H.; Akiyama, M.; Lukeš, P.
2014-01-01
The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H 2 O 2 ) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H 2 O 2 and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.
8. A new global analytical potential energy surface of NaH2+ system and dynamical calculation for H(2S) + NaH+(X2Σ+) → Na+(1S) + H2(X1Σg+) reaction
Science.gov (United States)
Yuan, Meiling; Li, Wentao; Yuan, Jiuchuang
2018-05-01
A new global potential energy surface (PES) of the NaH2+ system is constructed by fitting 27,621 ab initio energy points with the neural network method. The root mean square error of the new PES is only 4.1609 × 10-4 eV. Based on the new PES, dynamical calculations have been performed using the time-dependent quantum wave packet method. These results are then compared with the H(2S) + LiH+(X2Σ+) → Li+(1S) + H2(X1Σg+) reaction. The direct abstract mechanism is found to play an important role in the reaction because only forward scattering signals on the differential cross section results for all calculated collision energies.
9. Ethanol oxidation reactions catalyzed by water molecules: CH3CH2OH+n H2O→ CH3CHO+ H2+n H2O (n=0,1,2)
Science.gov (United States)
Takahashi, H.; Hisaoka, S.; Nitta, T.
2002-09-01
Ab initio density functional theory calculations have been performed to investigate the catalytic role of water molecules in the oxidation reaction of ethanol: CH3CH2OH+n H2O→ CH3CHO+ H2+n H2O (n=0,1,2) . The results show that the potential energy barrier for the reaction is 88.0 kcal/mol in case of n=0, while it is reduced by ˜34 kcal/mol when two water molecules are involved ( n=2) in the reaction. As a result, the rate constant increases to 3.31×10 -4 s-1, which shows a significant catalytic role of water molecules in the ethanol oxidation reactions.
10. Electrochemical studies of the effect of H2 on UO2 dissolution
International Nuclear Information System (INIS)
King, F.; Shoesmith, D.W.
2004-09-01
This report summarises evidence for the effect of H 2 on the oxidation and dissolution of UO 2 derived from electrochemical studies. In the presence of γ-radiation or with SIMFUEL electrodes containing ε-particles, the corrosion potential (E CORR ) of UO 2 is observed to be suppressed in the presence of H 2 by up to several hundred milli volts. This effect has been observed at room temperature with 5 MPa H 2 (in the case of γ-irradiated solutions) and at 60 deg C with a H 2 partial pressure of only 0.002-0.014 MPa H 2 with the SIMFUEL electrode. The suppression of E CORR in the presence of H 2 indicates that the degree of surface oxidation and the rate of dissolution of UO 2 is lower in the presence of H 2 .The precise mechanism of the effect of H 2 is unclear at this time. The mechanism appears to involve a surface heterogeneous process, rather than a homogeneous solution process. Under some circumstances the value of E CORR approaches the equilibrium potential for the H 2 /H + couple, suggesting galvanic coupling between sites on which this electrochemical process is catalysed and the rest of the UO 2 surface. It is also possible that H* radical species, either produced radiolytically from H 2 O or by dissociation of H 2 on ε-particles or surface-active UO 2+x sites, reduce oxidised U(V)/U(VI) surface states to U(IV). The effect of H 2 on reducing the degree of surface oxidation is only partially reversible, since surfaces reduced in H 2 atmospheres (re-)oxidise more slowly and to a lesser degree than surfaces not previously exposed to H 2 . Homogeneous reactions between dissolved H 2 and either oxidants or dissolved U(VI) cannot explain the observed effects.Regardless of the precise mechanism, the suppression of the degree of surface oxidation results in lower UO 2 dissolution rates in the presence of H 2 . Application of an electro-chemical dissolution model to the observed E CORR values suggests that the fractional dissolution rate of used fuel in the
11. Implications of electron attachment to highly-excited states in pulsed-power discharges
International Nuclear Information System (INIS)
Pinnaduwage, L.A.; Univ. of Tennessee, Knoxville, TN
1997-01-01
The author points out the possible implications of electron attachment to highly-excited states of molecules in two pulsed power technologies. One involves the pulsed H 2 discharges used for the generation of H ion beams for magnetic fusion energy and particle accelerators. The other is the power modulated plasma discharges used for material processing
12. High resolution spectroscopy of the Martian atmosphere - Study of seasonal variations of CO, O3, H2O, and T on the north polar cap and a search for SO2, H2O2, and H2CO
Science.gov (United States)
Krasnopolsky, V. A.; Chakrabarti, S.; Larson, H.; Sandel, B. R.
1992-01-01
An overview is presented of an observational campaign which will measure (1) the seasonal variations of the CO mixing ratio on the Martian polar cap due to accumulation and depletion of CO during the condensation and evaporation of CO2, as well as (2) the early spring ozone and water vapor of the Martian north polar cap, and (3) the presence of H2CO, H2O2, and SO2. The lines of these compounds will be measured by a combined 4-m telescope and Fourier-transform spectrometer 27097.
13. Vibrational spectroscopy of NO^+(H_2O)_n: Evidence for the intracluster reaction NO^+(H_2O)_n→H_3O^+(H_2O)_(n-2)(HONO) at n≥4
OpenAIRE
Choi, Jong-Ho; Kuwata, Keith T.; Haas, Bernd-Michael; Cao, Yibin; Johnson, Matthew S.; Okumura, Mitchio
1994-01-01
Infrared spectra of mass‐selected clusters NO^+(H_2O)_n for n=1 to 5 were recorded from 2700 to 3800 cm^(−1) by vibrational predissociation spectroscopy. Vibrational frequencies and intensities were also calculated for n=1 and 2 at the second‐order Møller–Plesset (MP2) level, to aid in the interpretation of the spectra, and at the singles and doubles coupled cluster (CCSD) level energies of n=1 isomers were computed at the MP2 geometries. The smaller clusters (n=1 to 3) were complexes of H_2O...
14. Transcriptome analysis of H2O2-treated wheat seedlings reveals a H2O2-responsive fatty acid desaturase gene participating in powdery mildew resistance.
Directory of Open Access Journals (Sweden)
Aili Li
Full Text Available Hydrogen peroxide (H(2O(2 plays important roles in plant biotic and abiotic stress responses. However, the effect of H(2O(2 stress on the bread wheat transcriptome is still lacking. To investigate the cellular and metabolic responses triggered by H(2O(2, we performed an mRNA tag analysis of wheat seedlings under 10 mM H(2O(2 treatment for 6 hour in one powdery mildew (PM resistant (PmA and two susceptible (Cha and Han lines. In total, 6,156, 6,875 and 3,276 transcripts were found to be differentially expressed in PmA, Han and Cha respectively. Among them, 260 genes exhibited consistent expression patterns in all three wheat lines and may represent a subset of basal H(2O(2 responsive genes that were associated with cell defense, signal transduction, photosynthesis, carbohydrate metabolism, lipid metabolism, redox homeostasis, and transport. Among genes specific to PmA, 'transport' activity was significantly enriched in Gene Ontology analysis. MapMan classification showed that, while both up- and down- regulations were observed for auxin, abscisic acid, and brassinolides signaling genes, the jasmonic acid and ethylene signaling pathway genes were all up-regulated, suggesting H(2O(2-enhanced JA/Et functions in PmA. To further study whether any of these genes were involved in wheat PM response, 19 H(2O(2-responsive putative defense related genes were assayed in wheat seedlings infected with Blumeria graminis f. sp. tritici (Bgt. Eight of these genes were found to be co-regulated by H(2O(2 and Bgt, among which a fatty acid desaturase gene TaFAD was then confirmed by virus induced gene silencing (VIGS to be required for the PM resistance. Together, our data presents the first global picture of the wheat transcriptome under H(2O(2 stress and uncovers potential links between H(2O(2 and Bgt responses, hence providing important candidate genes for the PM resistance in wheat.
15. Characterization of the bacterial community in a biotrickling filter treating high loads of H(2)S by molecular biology tools.
Science.gov (United States)
Maestre, Juan P; Rovira, Roger; Gamisans, Xavier; Kinney, Kerry A; Kirisits, Mary Jo; Lafuente, Javier; Gabriel, David
2009-01-01
The diversity and spatial distribution of bacteria in a lab-scale biotrickling filter treating high loads of hydrogen sulfide (H(2)S) were investigated. Diversity and community structure were studied by terminal-restriction fragment length polymorphism (T-RFLP). A 16S rRNA gene clone library was established. Near Full-length 16S rRNA gene sequences were obtained, and clones were clustered into 24 operational taxonomic units (OTUs). Nearly 74% and 26% of the clones were affiliated with the phyla Proteobacteria and Bacteroidetes, respectively. Beta-, epsilon- and gamma-proteobacteria accounted for 15, 9 and 48%, respectively. Around 45% of the sequences retrieved were affiliated to bacteria of the sulfur cycle including Thiothrix spp., Thiobacillus spp. and Sulfurimonas denitrificans. Sequences related to Thiothrix lacustris accounted for a 38%. Rarefaction curve demonstrated that clone library constructed can be sufficient to describe the vast majority of the bacterial diversity of this reactor operating under strict conditions (2,000 ppm(v) of H(2)S). A spatial distribution of bacteria was found along the length of the reactor by means of the T-RFLP technique. Although aerobic species were predominant along the reactor, facultative anaerobes had a major relative abundance in the inlet part of the reactor, where the sulfide to oxygen ratio is higher.
16. Intermolecular potential and rovibrational states of the H2O–D2 complex
International Nuclear Information System (INIS)
Avoird, Ad van der; Scribano, Yohann; Faure, Alexandre; Weida, Miles J.; Fair, Joanna R.; Nesbitt, David J.
2012-01-01
Graphical abstract: H 2 O–D 2 potential surface and pH 2 O–oD 2 ground state wave function, for planar geometries. Highlights: ► The interaction between H 2 O and H 2 is of great astrophysical interest. ► The rovibrational states of H 2 O–D 2 were computed on an ab initio potential surface. ► Results are compared with the rovibrational states of H 2 O–H 2 computed recently. ► We measured the high-resolution infrared spectrum of H 2 O–D 2 in the H 2 O bend region. ► Comparison with the calculations provides information on H 2 O–H 2 potential surface. - Abstract: A five-dimensional intermolecular potential for H 2 O–D 2 was obtained from the full nine-dimensional ab initio potential surface of Valiron et al. [P. Valiron, M. Wernli, A. Faure, L. Wiesenfeld, C. Rist, S. Kedžuch, J. Noga, J. Chem. Phys. 129 (2008) 134306] by averaging over the ground state vibrational wave functions of H 2 O and D 2 . On this five-dimensional potential with a well depth D e of 232.12 cm −1 we calculated the bound rovibrational levels of H 2 O–D 2 for total angular momentum J = 0–3. The method used to compute the rovibrational levels is similar to a scattering approach—it involves a basis of coupled free rotor wave functions for the hindered internal rotations and the overall rotation of the dimer—while it uses a discrete variable representation of the intermolecular distance coordinate R. The basis was adapted to the permutation symmetry associated with the para/ortho (p/o) nature of both H 2 O and D 2 , as well as to inversion symmetry. As expected, the H 2 O–D 2 dimer is more strongly bound than its H 2 O–H 2 isotopologue [cf. A. van der Avoird, D.J. Nesbitt, J. Chem. Phys. 134 (2011) 044314], with dissociation energies D 0 of 46.10, 50.59, 67.43, and 73.53 cm −1 for pH 2 O–oD 2 , oH 2 O–oD 2 , pH 2 O–pD 2 , and oH 2 O–pD 2 . A rotationally resolved infrared spectrum of H 2 O–D 2 was measured in the frequency region of the H 2 O bend
17. Reorganization of Damaged Chromatin by the Exchange of Histone Variant H2A.Z-2
Energy Technology Data Exchange (ETDEWEB)
2014-07-15
Purpose: The reorganization of damaged chromatin plays an important role in the regulation of the DNA damage response. A recent study revealed the presence of 2 vertebrate H2A.Z isoforms, H2A.Z-1 and H2A.Z-2. However, the roles of the vertebrate H2A.Z isoforms are still unclear. Thus, in this study we examined the roles of the vertebrate H2A.Z isoforms in chromatin reorganization after the induction of DNA double-strand breaks (DSBs). Methods and Materials: To examine the dynamics of H2A.Z isoforms at damaged sites, we constructed GM0637 cells stably expressing each of the green fluorescent protein (GFP)-labeled H2A.Z isoforms, and performed fluorescence recovery after photobleaching (FRAP) analysis and inverted FRAP analysis in combination with microirradiation. Immunofluorescence staining using an anti-RAD51 antibody was performed to study the kinetics of RAD51 foci formation after 2-Gy irradiation of wild-type (WT), H2A.Z-1- and H2A.Z-2-deficient DT40 cells. Colony-forming assays were also performed to compare the survival rates of WT, H2A.Z-1-, and H2A.Z-2-deficient DT40 cells with control, and H2A.Z-1- and H2A.Z-2-depleted U2OS cells after irradiation. Results: FRAP analysis revealed that H2A.Z-2 was incorporated into damaged chromatin just after the induction of DSBs, whereas H2A.Z-1 remained essentially unchanged. Inverted FRAP analysis showed that H2A.Z-2 was released from damaged chromatin. These findings indicated that H2A.Z-2 was exchanged at DSB sites immediately after the induction of DSBs. RAD51 focus formation after ionizing irradiation was disturbed in H2A.Z-2-deficient DT40 cells but not in H2A.Z-1-deficient cells. The survival rate of H2A.Z-2-deficient cells after irradiation was lower than those of WT and H2A.Z-1- DT40 cells. Similar to DT40 cells, H2A.Z-2-depleted U2OS cells were also radiation-sensitive compared to control and H2A.Z-1-depleted cells. Conclusions: We found that vertebrate H2A.Z-2 is involved in the regulation of the DNA
18. Calculated isotropic Raman spectra from interacting H2-rare-gas pairs
International Nuclear Information System (INIS)
Gustafsson, M; Głaz, W; Bancewicz, T; Godet, J-L; Maroulis, G; Haskapoulos, A
2014-01-01
We report on a theoretical study of the H 2 -He and H 2 -Ar pair trace-polarizability and the corresponding isotropic Raman spectra. The conventional quantum mechanical approach for calculations of interaction-induced spectra, which is based on an isotropic interaction potential, is employed. This is compared with a close-coupling approach, which allows for inclusion of the full, anisotropic potential. It is established that the anisotropy of the potential plays a minor role for these spectra. The computed isotropic collision-induced Raman intensity, which is due to dissimilar pairs in H 2 -He and H 2 -Ar gas mixtures, is comparable to the intensities due to similar pairs (H 2 -H 2 , He-He, and Ar-Ar), which have been studied previously
19. Reorganization of Damaged Chromatin by the Exchange of Histone Variant H2A.Z-2
International Nuclear Information System (INIS)
Nishibuchi, Ikuno; Suzuki, Hidekazu; Kinomura, Aiko; Sun, Jiying; Liu, Ning-Ang; Horikoshi, Yasunori; Shima, Hiroki; Kusakabe, Masayuki; Harata, Masahiko; Fukagawa, Tatsuo; Ikura, Tsuyoshi; Ishida, Takafumi; Nagata, Yasushi; Tashiro, Satoshi
2014-01-01
Purpose: The reorganization of damaged chromatin plays an important role in the regulation of the DNA damage response. A recent study revealed the presence of 2 vertebrate H2A.Z isoforms, H2A.Z-1 and H2A.Z-2. However, the roles of the vertebrate H2A.Z isoforms are still unclear. Thus, in this study we examined the roles of the vertebrate H2A.Z isoforms in chromatin reorganization after the induction of DNA double-strand breaks (DSBs). Methods and Materials: To examine the dynamics of H2A.Z isoforms at damaged sites, we constructed GM0637 cells stably expressing each of the green fluorescent protein (GFP)-labeled H2A.Z isoforms, and performed fluorescence recovery after photobleaching (FRAP) analysis and inverted FRAP analysis in combination with microirradiation. Immunofluorescence staining using an anti-RAD51 antibody was performed to study the kinetics of RAD51 foci formation after 2-Gy irradiation of wild-type (WT), H2A.Z-1- and H2A.Z-2-deficient DT40 cells. Colony-forming assays were also performed to compare the survival rates of WT, H2A.Z-1-, and H2A.Z-2-deficient DT40 cells with control, and H2A.Z-1- and H2A.Z-2-depleted U2OS cells after irradiation. Results: FRAP analysis revealed that H2A.Z-2 was incorporated into damaged chromatin just after the induction of DSBs, whereas H2A.Z-1 remained essentially unchanged. Inverted FRAP analysis showed that H2A.Z-2 was released from damaged chromatin. These findings indicated that H2A.Z-2 was exchanged at DSB sites immediately after the induction of DSBs. RAD51 focus formation after ionizing irradiation was disturbed in H2A.Z-2-deficient DT40 cells but not in H2A.Z-1-deficient cells. The survival rate of H2A.Z-2-deficient cells after irradiation was lower than those of WT and H2A.Z-1- DT40 cells. Similar to DT40 cells, H2A.Z-2-depleted U2OS cells were also radiation-sensitive compared to control and H2A.Z-1-depleted cells. Conclusions: We found that vertebrate H2A.Z-2 is involved in the regulation of the DNA
20. Electric discharge synthesis of HCN in simulated Jovian atmospheres
Science.gov (United States)
Stribling, Roscoe; Miller, Stanley L.
1987-01-01
Corona discharge is presently considered as a possible source of the HCN detected in the Jovian atmosphere at 2.2 x 10 to the -7th moles/sq cm column density, for the cases of gas mixtures containing H2, CH4, and NH3, with H2/CH4 ratios from 4.4 to 1585. A 3:1 ratio of corona discharge to lightning energy similar to that of the earth is applied to Jupiter. Depending on the lightning energy available on Jupiter and the eddy diffusion coefficients in the synthesis region, HCN column densities generated by corona discharge could account for about 10 percent of the HCN observed.
1. Diffuse H_{2} emission: a useful geochemical tool to monitor the volcanic activity at El Hierro volcano system
Science.gov (United States)
Pérez, Nemesio M.; Melián, Gladys; González-Santana, Judit; Barrancos, José; Padilla, Germán; Rodríguez, Fátima; Padrón, Eleazar; Hernández, Pedro A.
2016-04-01
cm depth using a metallic probe with a 60 cc hypodermic syringes and stored in 10 cc glass vials for later laboratory analysis by a VARIAN CP4900 micro-gas chromatograph. Soil H2 concentration data were used to estimate the H2 emission assuming a pure diffusive mechanism. The emission ranged between 12 and 25 kg d-1, showing a good relationship with the seismic energy release during the period of study. However, spatial distribution of H2 emission values did not show a clear relationship with main volcano-structures of El Hierro Island. H2 emission studies are a promising volcano monitoring technique that might help to detect early warning signals of volcanic unrest in oceanic volcanic islands. References Marini and Gambardella, 2005. Ann Geophys 48, 739-753. Giggenbach, 1987. Appl Geochem 2, 143-161. Smith-Downey et al., 2006. Geophys Res Lett 33, L14813.
2. The contribution of the Precambrian continental lithosphere to global H2 production.
Science.gov (United States)
Lollar, Barbara Sherwood; Onstott, T C; Lacrampe-Couloume, G; Ballentine, C J
2014-12-18
Microbial ecosystems can be sustained by hydrogen gas (H2)-producing water-rock interactions in the Earth's subsurface and at deep ocean vents. Current estimates of global H2 production from the marine lithosphere by water-rock reactions (hydration) are in the range of 10(11) moles per year. Recent explorations of saline fracture waters in the Precambrian continental subsurface have identified environments as rich in H2 as hydrothermal vents and seafloor-spreading centres and have suggested a link between dissolved H2 and the radiolytic dissociation of water. However, extrapolation of a regional H2 flux based on the deep gold mines of the Witwatersrand basin in South Africa yields a contribution of the Precambrian lithosphere to global H2 production that was thought to be negligible (0.009 × 10(11) moles per year). Here we present a global compilation of published and new H2 concentration data obtained from Precambrian rocks and find that the H2 production potential of the Precambrian continental lithosphere has been underestimated. We suggest that this can be explained by a lack of consideration of additional H2-producing reactions, such as serpentinization, and the absence of appropriate scaling of H2 measurements from these environments to account for the fact that Precambrian crust represents over 70 per cent of global continental crust surface area. If H2 production via both radiolysis and hydration reactions is taken into account, our estimate of H2 production rates from the Precambrian continental lithosphere of 0.36-2.27 × 10(11) moles per year is comparable to estimates from marine systems.
3. Transfer of π- from hydrogen to deuterium in H2O + D2O mixtures
International Nuclear Information System (INIS)
Stanislaus, S.; Measday, D.F.; Vetterli, D.; Weber, P.; Aniol, K.A.; Harston, M.R.; Armstrong, D.S.
1989-07-01
The transfer of stopping π - mesons from hydrogen to deuterium has been investigated in mixtures of H 2 O+D 2 O as a function of D 2 O concentration. The concentration dependence of the transfer probability is similar to that observed for the gas mixtures of H 2 and D 2 but slightly more transfer is found for H 2 O+D 2 O. (Author) 17 refs., 2 tabs., 4 figs
4. Non-LTE H2+ as the source of missing opacity in the solar atmosphere
Science.gov (United States)
Swamy, K. S. K.; Stecher, T. P.
1974-01-01
The population of the various vibrational levels of the H2+ molecule has been calculated from the consideration of formation and destruction mechanisms. The resulting population is used in calculating the total absorption due to H2+ and is compared with the other known sources of opacity at several optical depths of the solar atmosphere. It is shown that the absorption due to H2+ can probably account for the missing ultraviolet opacity in the solar atmosphere.
5. Comparison of genes required for H2O2 resistance in Streptococcus gordonii and Streptococcus sanguinis
Science.gov (United States)
Xu, Yifan; Itzek, Andreas
2014-01-01
Hydrogen peroxide (H2O2) is produced by several members of the genus Streptococcus mainly through the pyruvate oxidase SpxB under aerobic growth conditions. The acute toxic nature of H2O2 raises the interesting question of how streptococci cope with intrinsically produced H2O2, which subsequently accumulates in the microenvironment and threatens the closely surrounding population. Here, we investigate the H2O2 susceptibility of oral Streptococcus gordonii and Streptococcus sanguinis and elucidate potential mechanisms of how they protect themselves from the deleterious effect of H2O2. Both organisms are considered primary colonizers and occupy the same intraoral niche making them potential targets for H2O2 produced by other species. We demonstrate that S. gordonii produces relatively more H2O2 and has a greater ability for resistance to H2O2 stress. Functional studies show that, unlike in Streptococcus pneumoniae, H2O2 resistance is not dependent on a functional SpxB and confirms the important role of the ferritin-like DNA-binding protein Dps. However, the observed increased H2O2 resistance of S. gordonii over S. sanguinis is likely to be caused by an oxidative stress protection machinery present even under anaerobic conditions, while S. sanguinis requires a longer period of time for adaptation. The ability to produce more H2O2 and be more resistant to H2O2 might aid S. gordonii in the competitive oral biofilm environment, since it is lower in abundance yet manages to survive quite efficiently in the oral biofilm. PMID:25280752
6. Absolute linestrengths in the H2O2 nu6 band
Science.gov (United States)
May, Randy D.
1991-01-01
Absolute linestrengths at 295 K have been measured for selected lines in the nu6 band of H2O2 using a tunable diode-laser spectrometer. H2O2 concentrations in a flowing gas mixture were determined by ultraviolet (uv) absorption at 254 nm using a collinear infrared (ir) and uv optical arrangement. The measured linestrengths are approx. 60 percent larger than previously reported values when absorption by hot bands in H2O2 is taken into account.
7. Dissociative ionization of H2 and D2 by electron impact near threshold
NARCIS (Netherlands)
Boesten, L.G.J.; Heideman, H.G.M.
We have studied the dissciative ionization of H2 and D2 by electron impact. It is found that in the vicinity of the 2Σ+g dissociation threshold of H+2 (18.08 eV) a significant fraction of the produced protons originates from the process e + H2 → H− + H+ + e (threshold at 17.34 eV). Similar results
8. 40 CFR 1065.370 - CLD CO2 and H2O quench verification.
Science.gov (United States)
2010-07-01
... 40 Protection of Environment 32 2010-07-01 2010-07-01 false CLD CO2 and H2O quench verification....370 CLD CO2 and H2O quench verification. (a) Scope and frequency. If you use a CLD analyzer to measure NOX, verify the amount of H2O and CO2 quench after installing the CLD analyzer and after major...
9. Some physico-chemical characteristics of a modified histone H2b on acute radiation affection
International Nuclear Information System (INIS)
Khrapunov, S.N.; Mel'nik, G.G.; Blyum, Ya.B.; Tsudzevich, B.A.; Kucherenko, N.E.
1980-01-01
A study was made of optical characteristics of histone H2b isolated from liver nuclei 12 h following irradiation in a dose of 0.21 C/kg. It was demonstrated that under similar conditions, the control and exposed histones H2b have different steric organization which correlates with radiation-induced modifications of lateral radicals in H2b histone molecules
10. H2@Scale: Technical and Economic Potential of Hydrogen as an Energy Intermediate
Energy Technology Data Exchange (ETDEWEB)
Ruth, Mark F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jadun, Paige [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Pivovar, Bryan S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2017-11-09
The H2@Scale concept is focused on developing hydrogen as an energy carrier and using hydrogen's properties to improve the national energy system. Specifically hydrogen has the abilities to (1) supply a clean energy source for industry and transportation and (2) increase the profitability of variable renewable electricity generators such as wind turbines and solar photovoltaic (PV) farms by providing value for otherwise potentially-curtailed electricity. Thus the concept also has the potential to reduce oil dependency by providing a low-carbon fuel for fuel cell electric vehicles (FCEVs), reduce emissions of carbon dioxide and pollutants such as NOx, and support domestic energy production, manufacturing, and U.S. economic competitiveness. The analysis reported here focuses on the potential market size and value proposition for the H2@Scale concept. It involves three analysis phases: 1. Initial phase estimating the technical potential for hydrogen markets and the resources required to meet them; 2. National-scale analysis of the economic potential for hydrogen and the interactions between willingness to pay by hydrogen users and the cost to produce hydrogen from various sources; and 3. In-depth analysis of spatial and economic issues impacting hydrogen production and utilization and the markets. Preliminary analysis of the technical potential indicates that the technical potential for hydrogen use is approximately 60 million metric tons (MMT) annually for light duty FCEVs, heavy duty vehicles, ammonia production, oil refining, biofuel hydrotreating, metals refining, and injection into the natural gas system. The technical potential of utility-scale PV and wind generation independently are much greater than that necessary to produce 60 MMT / year hydrogen. Uranium, natural gas, and coal reserves are each sufficient to produce 60 MMT / year hydrogen in addition to their current uses for decades to centuries. National estimates of the economic potential of
11. Potential Size of and Value Proposition for H2@Scale Concept
Energy Technology Data Exchange (ETDEWEB)
Ruth, Mark F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jadun, Paige [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Pivovar, Bryan S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Elgowainy, Amgad [Argonne National Laboratory
2017-11-09
The H2@Scale concept is focused on developing hydrogen as an energy carrier and using hydrogen's properties to improve the national energy system. Specifically hydrogen has the abilities to (1) supply a clean energy source for industry and transportation and (2) increase the profitability of variable renewable electricity generators such as wind turbines and solar photovoltaic (PV) farms by providing value for otherwise potentially-curtailed electricity. Thus the concept also has the potential to reduce oil dependency by providing a low-carbon fuel for fuel cell electric vehicles (FCEVs), reduce emissions of carbon dioxide and pollutants such as NOx, and support domestic energy production, manufacturing, and U.S. economic competitiveness. The analysis reported here focuses on the potential market size and value proposition for the H2@Scale concept. It involves three analysis phases: 1. Initial phase estimating the technical potential for hydrogen markets and the resources required to meet them; 2. National-scale analysis of the economic potential for hydrogen and the interactions between willingness to pay by hydrogen users and the cost to produce hydrogen from various sources; and 3. In-depth analysis of spatial and economic issues impacting hydrogen production and utilization and the markets. Preliminary analysis of the technical potential indicates that the technical potential for hydrogen use is approximately 60 million metric tons (MMT) annually for light duty FCEVs, heavy duty vehicles, ammonia production, oil refining, biofuel hydrotreating, metals refining, and injection into the natural gas system. The technical potential of utility-scale PV and wind generation independently are much greater than that necessary to produce 60 MMT / year hydrogen. Uranium, natural gas, and coal reserves are each sufficient to produce 60 MMT / year hydrogen in addition to their current uses for decades to centuries. National estimates of the economic potential of
12. Habitat sequencing and the importance of discharge in inferences
Science.gov (United States)
Robert H. Hilderbrand; A. Dennis Lemly; C. Andrew Dolloff
1999-01-01
The authors constructed stream maps for a low-Âgradient trout stream in southwestern Virginia during autumn (base flow) and spring (elevated flows) to compare spatial and temporal variation in stream habitats. Pool-riffle sequencing and total area occupied by pools and riffles changed substantially depending on the level of discharge: reduced discharge resulted in an...
13. The H2A-H2B dimeric kinetic intermediate is stabilized by widespread hydrophobic burial with few fully native interactions.
Science.gov (United States)
Guyett, Paul J; Gloss, Lisa M
2012-01-20
The H2A-H2B histone heterodimer folds via monomeric and dimeric kinetic intermediates. Within ∼5 ms, the H2A and H2B polypeptides associate in a nearly diffusion limited reaction to form a dimeric ensemble, denoted I₂ and I₂*, the latter being a subpopulation characterized by a higher content of nonnative structure (NNS). The I₂ ensemble folds to the native heterodimer, N₂, through an observable, first-order kinetic phase. To determine the regions of structure in the I₂ ensemble, we characterized 26 Ala mutants of buried hydrophobic residues, spanning the three helices of the canonical histone folds of H2A and H2B and the H2B C-terminal helix. All but one targeted residue contributed significantly to the stability of I₂, the transition state and N₂; however, only residues in the hydrophobic core of the dimer interface perturbed the I₂* population. Destabilization of I₂* correlated with slower folding rates, implying that NNS is not a kinetic trap but rather accelerates folding. The pattern of Φ values indicated that residues forming intramolecular interactions in the peripheral helices contributed similar stability to I₂ and N₂, but residues involved in intermolecular interactions in the hydrophobic core are only partially folded in I₂. These findings suggest a dimerize-then-rearrange model. Residues throughout the histone fold contribute to the stability of I₂, but after the rapid dimerization reaction, the hydrophobic core of the dimer interface has few fully native interactions. In the transition state leading to N₂, more native-like interactions are developed and nonnative interactions are rearranged. Copyright © 2011 Elsevier Ltd. All rights reserved.
14. Cross sections for Scattering and Mobility of OH- and H3 O+ ions in H2 O
Science.gov (United States)
Petrovic, Zoran; Stojanovic, Vladimir; Maric, Dragana; Jovanovic, Jasmina
2016-05-01
Modelling of plasmas in liquids and in biological and medical applications requires data for scattering of all charged and energetic particles in water vapour. We present swarm parameters for OH- and H3 O+, as representatives of principal negative and positive ions at low pressures in an attempt to provide the data that are not yet available. We applied Denpoh-Nanbu procedure to calculate cross section sets for collisions of OH- and H3 O+ ions with H2 O molecule. Swarm parameters for OH- and H3 O+ ions in H2 O are calculated by using a well tested Monte Carlo code for a range of E / N(E -electric field, N-gas density) at temperature T = 295 K, in the low pressure limit. Non-conservative processes were shown to strongly influence the transport properties even for OH- ions above the average energy of 0.2 eV(E / N >200 Td). The data are valid for low pressure water vapour or small amounts in mixtures. They will provide a basis for calculating properties of ion-water molecule clusters that are most commonly found at higher pressures and for modelling of discharges in liquids. Acknowledgment to Ministry of Education, Science and Technology of Serbia.
15. Stress management skills in the subsurface: H2 stress on thermophilic heterotrophs and methanogens
Science.gov (United States)
Topcuoglu, B. D.; Holden, J. F.
2017-12-01
Marine hyperthermophilic heterotrophs and methanogens belonging to the Thermococcales and Methanococcales are often found in subsurface environments such as coal and shale beds, marine sediments, and oil reservoirs where they encounter H2 stress conditions. It is important to study the H2 stress survival strategies of these organisms and their cooperation with one another for survival to better understand their biogeochemical impact in hot subsurface environments. In this study, we have shown that H2 inhibition changed the growth kinetics and the transcriptome of Thermococcus paralvinellae. We observed a significant decrease in batch phase growth rates and cell concentrations with high H2 background. Produced metabolite production measurements, RNA-seq analyses of differentially expressed genes and in silico experiments we performed with the T. paralvinellae metabolic model showed that T. paralvinellae produces formate by a formate hydrogenlyase to survive H2 inhibition. We have also shown that H2 limitation caused a significant decrease in batch phase growth rates and methane production rates of the methanogen, Methanocaldococcus jannaschii. H2 stress of both organisms can be ameliorated by syntrophic growth. H2 syntrophy was demonstrated in microcosm incubations for a natural assemblage of Thermococcus and hyperthermophilic methanogens present in hydrothermal fluid samples. This project aims to describe how a hyperthermophilic heterotroph and a hyperthermophilic methanogen eliminate H2 stress and explore cooperation among thermophiles in the hot subsurface.
16. Effect of H2O2 on the corrosion behavior of 304L stainless steel
International Nuclear Information System (INIS)
Song, Taek Hoh; Kim, In Sub; Noh, Sung Kee
1995-01-01
In connection with the safe storage of high level nuclear waste, effect of H 2 O 2 on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H 2 O 2 . The experimental results show that H 2 O 2 increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H 2 O 2 concentration increased, indicating that pitting resistance was decreased by the existence of H 2 O 2 in the electrolyte. These effects of H 2 O 2 on corrosion of 304L stainless steel are consi | {"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": 0.8010567426681519, "perplexity": 6496.611390366954}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-39/segments/1537267156460.64/warc/CC-MAIN-20180920101233-20180920121633-00309.warc.gz"} |
https://asmedigitalcollection.asme.org/FUELCELL/proceedings-abstract/FUELCELL2010/44052/357/363121 | The effect of different operating parameters on carbon corrosion in polymer electrolyte fuel cells was investigated by applying single triangular potential pulses to cells operated in H2/N2 mode. Corrosion rates were determined by integration of the resulting CO2 concentration peaks in the cathode exhaust gas. A significant effect of the lower voltage limit was observed which was attributed to a partial inhibition of the platinum catalyzed corrosion pathway through the formation of a stable oxide layer on the platinum surface. Humidity variation experiments showed a linear correlation between carbon corrosion rate and water vapor partial pressure. However, corrosion rate strongly decreased at low relative humidity, showing that both absolute and relative water content influence corrosion. Since the distinction between the influence of absolute and relative water content is not clear yet, interpretation of temperature effects is difficult. In case of fully humidified gases, corrosion rates showed an exponential-like increase with increasing temperature. In order to assess the relevance for real start-up and shut-down processes, carbon corrosion rates were compared to degradation data obtained in application oriented start/stop cycling experiments, which were carried out by alternating purging of the anode compartment with hydrogen and air. Generally, fuel cell performance loss rates are in good agreement with corrosion rates determined in potential pulse experiments. Due to the high complexity of real start-up and shut-down processes, however, potential pulse experiments can not provide an accurate prediction of start/stop induced degradation behavior.
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https://www.gurobi.com/documentation/9.0/refman/py_readparams.html | # Documentation
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Read a set of parameter settings from a file. The file name must end in .prm, and the file must be in PRM format.
readParams("params.prm") | {"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": 0.3551081418991089, "perplexity": 6969.563642566967}, "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/1575540584491.89/warc/CC-MAIN-20191214042241-20191214070241-00243.warc.gz"} |