I learned that inside a battery, when we put a circuit, the battery takes electrons on the positive side and do force on them to place them in the negative side. This work done is converted into potential energy for the electrons and they are ready to enter the wire. Is there something I don't understand?  For example in this battery here :   there is no place for the electrons to move from the positive side to the negative side, except the salt bridge but it only conducts ions. Do the electrons get transported in the electrolyte via ions and then released in the negative terminal?
I would like to know why does electrons flow through a wire connected to a battery as said in .It tells that "the electrons that are stripped from the carbon electrode is collected on the zinc can" and then tells     The electrons at the negative terminal want to go to positive terminal, they just need a way to get there. In our light bulb circuit, the way to get there is through the wire.   Why couldn't the electrons go to the positive terminal through the electrolyte(potassium hydroxide) instead of going through the wire?
Is there a way to get the raw SQL string executed when calling PDOStatement::execute() on a prepared statement? For debugging purposes this would be extremely useful. I tried the following code to replace QQ with ZZ, but it doesn't do what I want:  var1=QQ sed -i 's/$var1/ZZ/g' $file   However, this code does what I want:  sed -i 's/QQ/ZZ/g' $file   How do I use variables in sed? So I have a Palm Pre (original P100EWW) model that I enabled developer mode on, and installed a Debian Squeeze chroot.  Works great.  I have plans to use this for ANYTHING (bittorrent peer, web server) but a phone.  I noticed if I do a cat /dev/urandom &gt; /dev/fb0 it actually writes random pixels to the screen until a No space left on device error is generated.  Awesome, now I can use the display.  So what kind of utilites are there that will either A) let me use /dev/fb0 as a console I can output text to or B) render text on /dev/fb0 from the command line.  I don't know about recompiling the kernel for this yet (I'd love to eventually strip WebOS off entirely and turn this into a minimal ARM server) so userspace tools if they exist is what I'm asking about.  Also would prefer to render directly to /dev/fb0 and not use X. How do I perform a biographical interview? I have a couple of elderly relatives who have not kept a journal and refuse to write down their "life story." I really would like to know their stories and who they were and who they are. They have their favorite stories that they rehash every time I see them, but I'd like to get more. I have no experience with "interviewing" and am looking for information on how to get their stories. Any websites, books, and or tips\techniques would be greatly appreciated. How to have a figure with caption in multicol environment? I am having the following problem with adding a figure inside the multicol environment:  \documentclass[10pt, twoside]{book} \usepackage{graphicx} \usepackage{subfig}  \begin{document}   \begin{multicols}{2}  a test file for picture inclusion along with the captions and labeling \begin{figure}  \centering  \includegraphics[width=5cma]{Cauchy_sequence_illustration-png}\\  \caption{Lets see}\label{pinki} \end{figure} \end{multicols}  \begin{figure}  \centering   \includegraphics[width=5cm]{Cauchy_sequence_illustration-png}\\  \caption{Lets see}\label{pinki} \end{figure}    \end{document}    After this while I am pressing Ctrl + Shift + X (usually I compile like this in DVI format and then clicking "dvi--->pdf" I convert it into PDF document.) the picture in multicol environment is not shown in YAP Viewer but the second one (which is outside of multicol environment) is shown along with the caption.  Kindly help me how to handle this problem. Please note that I am using the figure in .ps format. And I am not allowed to use any other format according to the instruction. All of my Firefox add-ons have been disabled suddenly, how can I re-enable them? Which of $\{J_0,J_1,J_2\}$ and $\{J_0,J_+,J_-\}$ is a generator for the Lie algebra $\mathfrak{su}(2)$? I have just started learning about Lie algebra in the context of quantum mechanics and got confused with this: Some sources say the generators are $J_0,J_1$ and $J_2$ and some use $J_0,J_+$ and $J_−$. Which set is correct? Or if both are correct what key concept am I missing here? My understanding is that if have certain commutation relations then we know that Lie Algebra is such and such. But if we have two such choices then this understanding falls apart? How do I figure out what is $\mathfrak{su}(2)$ Lie Algebra in general? Opening website external links in new window -- published usability tests PDF of function of X I'm learning about functions of random variables and am trying to work out an example I made up. If $y = \sin(x)$ and $x$ has domain $[0, 4\pi]$, is the following the correct expression for the pdf of $y$: $$\begin{align*} f_Y(y) &amp;= \frac{d}{dy}F_Y(y)\\ &amp;= \frac{d}{dy}[F_X(2\pi) - F_X(\pi) + F_X(4\pi) - F_X(3\pi)]\\ &amp;= \frac{d}{dx}F_X(2\pi)\left|\frac{dg^{-1}(y)}{dy}\right| - \frac{d}{dx}F_X(\pi)\left|\frac{dg^{-1}(y)}{dy}\right| + \frac{d}{dx}F_X(4\pi)\left|\frac{dg^{-1}(y)}{dy}\right| - \frac{d}{dx}F_X(3\pi)\left|\frac{dg^{-1}(y)}{dy}\right|\\ &amp;=f_X(2\pi)\left|\frac{1}{\sqrt{1-0}}\right| - f_X(\pi)\left|\frac{1}{\sqrt{1-0}}\right| + f_X(4\pi)\left|\frac{1}{\sqrt{1-0}}\right| - f_X(3\pi)\left|\frac{1}{\sqrt{1-0}}\right|\\ &amp;= f_X(2\pi) - f_X(\pi) + f_X(4\pi) - f_X(3\pi)\\ \end{align*}$$ Can anyone explain IEnumerable and IEnumerator to me? Can anyone explain IEnumerable and IEnumerator to me? For example, when to use it over foreach? what's the difference between IEnumerable and IEnumerator? Why do we need to use it? Every Hilbert space has an orthonomal basis - using Zorn's Lemma The problem is to prove that every Hilbert space has a orthonormal basis. We are given Zorn's Lemma, which is taken as an axiom of set theory:  Lemma If X is a nonempty  with the property that every  of X has an upper bound in X, then X has a maximal element.   Given a orthonormal set $E$ in a Hilbert space $H$, it is apparently possible to show that $H$ has an orthonormal basis containing $E$.   I tried to reason as follows: Suppose $E$ is a finite set of $n$ elements. Then one can number the elements of $E$ to create a totally ordered set of orthonormal elements. Then the span $&lt;E&gt;$ can be identified with $R^n$, where each element $v = v_1 e_1 + v_2 e_2 + ... + v_n e_n$ is identified with the vector $(v_1, v_2, ..., v_n)$. On $R^n$ we have a total order, namely the "lexigraphical order" $(x_1,x_2,...,x_n) \leq (y_1,y_2,...,y_n)$ if $x_1 &lt; y_1$ or if $x_1 = y_1$ and $x_2 &lt; y_2$ or if $x_1 = y_1$, $x_2 = y_2$ and $x_3 &lt; y_3$ and so on. Hence $E$ is a totally ordered subset of $H$ and $H$ is a partially ordered set. However, this set doesn't seem to have an upper bound. The set $E$ does have an upper bound. If we define a total order on $E$ only, then X is a partially ordered set satisfying the criteria so X has a maximal element?   This is as far as I got, and I am not sure the entire argument is correct. I don't see how what kind of maximal element I am seeking, since the orthonormal basis of a Hilbert space can have countably infinity number of elements. Increasing spacing between section number and title in the table of contents I'm using the simple ordinary \tableofcontents command to produce a table of contents, and I find that the resulting spacing between the section number and the section title is too small:    Can someone tell me how to fix this, please. My documentclass is memoir, if that matters. Why does the right leg's bone in my rig move when I move the left? For some reason, when I moved the left leg's bone, the right leg has also moved and the bone of the right leg doesn't control anything at all.  I think this is because I used Mirror to make the model, but I'm not sure I'm a complete beginner. Digging in deeper to Javascript Remoting and I'm a bit confused.  The  starts off by showing how to set up everything and uses code like the following:  function getRemoteAccount() {     var accountName = document.getElementById('acctSearch').value;      // This remoting call will use the page's timeout value     Visualforce.remoting.Manager.invokeAction(         '{!$RemoteAction.AccountRemoter.getAccount}',         accountName,          handleResult     ); }   However, I've also seen examples where Visualforce.remoting.Manager.invokeAction is never called.  They end up looking something like the following:  function getText() {   var text = "";   JSRemotingBasicsController.doGetText(     function(result, event) {       // do something here     }   ); }   I'm wondering what is the point to using Visualforce.remoting.Manager.invokeAction when you can just reference the RemoteAction directly like the second example?  Is there something I'm missing?  Is there a time where the second example doesn't work? What are the best textbooks to read for the mathematical background you need for modern physics, such as, string theory?  Some subjects off the top of my head that probably need covering:   Differential geometry, Manifolds, etc. Lie groups, Lie algebras and their representation theory. Algebraic topology. Let $X$ be a non-negative random variable and $F_{X}$ the corresponding CDF. Show,   $$E(X) = \int_0^\infty (1-F_X (t)) \, dt$$   when $X$ has : a) a discrete distribution, b) a continuous distribution.   I assumed that for the case of a continuous distribution, since $F_X (t) = \mathbb{P}(X\leq t)$, then $1-F_X (t) = 1- \mathbb{P}(X\leq t) = \mathbb{P}(X&gt;  t)$. Although how useful integrating that is, I really have no idea. Mann-Whitney U test and K-S test with unequal sample sizes Please be kind, I am an electronics nub.  This is in reference to getting an LED to emit photons.  From what I read (Getting Started in Electronics - Forrest Mims III and Make: Electronics) electrons flow from the more negative side to the more positive side.  In an example experiment (involving a primary dry cell, a SPDT switch, a resistor and an LED) it states that the resistor MUST be connected to the anode of the LED.  In my mind, if the electrons flow from negative to positive, wouldn't the electron flow run through the LED before the resistor; thereby making the resistor pointless? Add time restriction in ArcGIS Network Analyst I'm trying to use train tracks as a network in ArcGIS Network Analyst.   We are trying to create a model for security agents on board our trains and we'd like to optimize their daily "route". For now, it's all made by hand.   My approach is to take our gtfs data and create a network using stop times to determine when the train segment is "traversable". When there's a train on the segment, it's open, if not, it's restricted.   The problem is I can't set a restriction based on time in Network Analyst (or wasn't able to). I would like to be able to say by a formula or script than you can take that segment only from 7:03 AM to 7:10 AM for example.  Is it possible?  Thanks! How to Fix "Read-only file system" error when I run something as sudo and try to make a folder/file? When I try to save something or rename a file/folder it say this error " Read-only file system" or run something as root in the terminal it say this error  sudo: unable to open /var/lib/sudo/"My User Name"/0: Read-only file system  W: Not using locking for read only lock file /var/lib/dpkg/lock E: Unable to write to /var/cache/apt/   E: The package lists or status file could not be parsed or opened.   When I make a Folder the error dialog in the details with Nautilus is this:    Error creating directory: Read-only file system   I would show you I picture of it but it isn't even letting my save onto my flash drive. Please help me.