The other night, I found myself crashing at a friend's house without a MicroUSB charger handy. As such, my phone (Nokia Lumia 920) died before I went to bed - attempting to boot would simply yield a "low battery" screen. When I awoke about 6 hours later, I decided (in a moment surely befitting the definition of insanity) to try turning the phone on again. The phone booted this time, showing about 12% battery remaining. Aside from the expected "low battery" warning messages, I was allowed to use the phone normally for awhile before I finally got back into my car and was able to charge it there.  I'm pretty sure I've seen this phenomenon in other small electronics (usually phones). A device will have drained its battery to the point of being un-bootable but, after a few hours or so, I'll later try again and find it coming to life as if nothing was wrong.  What causes this?
I carry a small 2-AA flashlight, and a few times, I have accidentally left it on in my holder.  Each time it dies completely, so that no light is emitted, but if I turn it back off and wait for a few minutes, the light works weakly again.  The longer I leave it off, the longer the dead battery lasts.  I've noticed similar patterns in my mobile phone battery.    Why does this happen?
Capture stdout and stderr into different variables Find Documents in MongoDB whose with an array field is a subset of a query array How to setup OpenVPN Client Checking for sublist in list I'm giving training to a large group of people remotely and will be covering a number of application shortcut keys.  I've seen 's on-screen display of keystrokes; is there a similar product for Windows?    The other features of MousePose (fancy mouse pointers, etc.) aren't really useful to me, just the OSD of key presses. Why do you need 2 resistors when hooking up a transistor as a switch What is the point of R2 in the following diagram:   I get that R1 controls the current to the Base, but what does R2 do? How to convert local time string to UTC? Table overflowing outside of div Why does virtualbox only have 32-bit option, no 64-bit option on Windows 7? I have downloaded and installed the newest  for my Windows 7 (64-bit OS), but when I want to install 64-bit Linux, the New->Create Virtual Machine only displays 32-bit option, no 64-bit option. Could anyone give any clues about this issue? Thanks very much in advance! How to add Windows to GRUB I have my encrypted Archlinux installed on my SSD. Now I have one HDD with Windows installed. But in my GRUB just Archlinux is shown (no Wonder, because I just installed Windows on the other HDD, GRUB doesn't know of that by now.).  My Question is, how do I properly add my Windows-HDD to GRUB, so that I can choose which to boot when starting?  I am a little bit afraid of destroying my GRUB so I can't boot my encrypted Archlinux anymore.  Thanks! Abiword starts automatically each restart Abiword starts automatically each restart, on any user. Already checked out Startup Applications. Remember session is turned off.   ()  Additional info, may be it'll give a clue - I configured VNC server on this machine to run, so sometimes, in additional to regular Ubuntu/Unity sessions I start XFCE4 session. I think this behavior started after VNC4 configuration, but ~/.vnc/xstartup does not contain abiword - just regular xfce startup stuff.  What are additional places where I can look? How to zoom in/out an UIImage object when user pinches screen? Im not familiar with Ubuntu or Linux in general but have succesfully installed dual-boot windows7/Ubuntu on a single harddisk on my private PC. I used the "Install Ubuntu alongside them"-option.   On my work PC I have an existing windows 7 64-bit installation that boots from BIOS firmware on a SSD drive (C:), and have my working data (documents etc) on a partition on a separate disk (D:). I now want to install Ubuntu (v 14.04.3) on the remaining unformatted space on D:\ using with the option of choosing system using GRUB. There are of cause fine descriptions around (e.g.  and ). My question is how to setup the partitions in the "something else"- option during the Ubuntu installation.   In  tutorial they assume that all partitions on the D-drive can be deleted; however I only obviously want to keep the working data on the existing D-partition, and place Ubuntu on the residual space (or part of it) on the D:-drive.  A) How is this ensured ? B) how many partitions should I make (boot, root, home, swap ?)  C) and should boot be made primary, and the others logical ? D) Should I set Device for boot loader installation as/dev/sdb - will this not erase the existing D-partion ? How is the equation of motion on an ellipse derived? I would like to show that a particle orbiting another will follow the trajectory   \begin{equation} r = \frac{a(1-e^2)}{1 + e \cos(\theta)}. \end{equation}  I would like to do this with minimal assumptions. Any pointers? I've read that this is nothing but the equation for an ellipse, as defined from the focus of the ellipse. But I'm not satisfied in just taking the result, I mean why should I assume that orbits are elliptical? I guess it should be derivable from energy and angular momentum considerations... Usage of italics in writing How to emulate titletoc with tocloft I was using titletoc until I realized that it has some incompatibilities with hyperref. The thing is, that titletoc can do the same thing in a easier way, less one.  \titlecontents*{subsection}[5.4em] {\small} {\thecontentslabel~ } {} {} [.~\textbullet\ ] [.]   this part does the subsection as a paragraph (with section number and without page number). I have realized that the problem is the pseudo-code used by tocloft for the entries in the TOC  {\cftXfont {\cftXpresnum SNUM\cftXaftersnum\hfil} \cftXaftersnumb TITLE}% {\cftXleader}{\cftXpagefont PAGE}\cftXafterpnum\par   I mean, the last command \par make impossible to leave two subsection entries in the same textline. Any idea? Another interesting solution is with etoolbox, some examples with that package are awesome, but it's not on my hands.  This is a MWE:  \documentclass{book}  \usepackage{titletoc} \titlecontents*{subsection}[5.4em]{\small} {\thecontentslabel~ }{}{}[.~\textbullet\ ][.]  \begin{document}  \tableofcontents  \chapter{Test Chapter 1} \section{Test Section 1.1} \subsection{First Test Subsection} \subsection{Second Test Subsection} \subsection{Third Test Subsection} \subsection{Fourth Test Subsection} \section{Test Section 1.2} \subsection{First Test Subsection} \subsection{Second Test Subsection}  \chapter{Test Chapter 2} \section{Test Section 2.1} \subsection{First Test Subsection} \subsection{Second Test Subsection} \subsection{Third Test Subsection} \subsection{Fourth Test Subsection} \section{Test Section 2.2} \subsection{First Test Subsection} \subsection{Second Test Subsection}  \end{document} We now that Fermat's last theorem is true so there are not positive integer solutions to $$x^n+y^n=z^n$$ for $n\in\mathbb{N}$ and $n&gt;2$.  But what about if $n\in\mathbb{R}$ or $n\in\mathbb{R}^+$? A continuous bijection from a compact space to a $T_2$ space is always a homeomorphism This problem is bugging me for some time.     $f:(X,\mathcal{T}) \to (Y,\mathcal{T}')$ is a continuous bijection where $(X,\mathcal{T})$ is compact and $(Y,\mathcal{T}')$ is $T_2$ (i.e. Hausdorff and $T_1$). Then show that $f$ must be a homeomorphism.   So far I have failed to understand any relation between the compactness of domain and $T_2$-ness of the range. I tried in vain to prove that $f(U)$ is open in $(Y,\mathcal{T}')$ whenever $U$ is so in $(X,\mathcal{T})$. I know $f$ makes $X$ and $Y$ respectively $T_2$ and compact and hence makes both of them $T_4$ spaces. But that is not coming to any use. I would be glad if someone helps me with a solution. Thank you. Photons have no mass but they can push things, as evidenced by .   Can photons push the source which is emitting them? If yes, will a more intense flashlight accelerate me more? Does the wavelength of the light matter? Is this practical for space propulsion? Doesn't it defy the law of momentum conservation?  Note: As John Rennie mentioned, all in all the wavelength doesn't matter, but for a more accurate answer regarding that, see the comments in  .  Related Wikipedia articles: , How large would the steam explosion at Chernobyl have been? So the  of the HBO series began to cover the  that led to them sending three divers into the water below the reactor to drain the tanks.  This occurred after the initial explosion that destroyed the reactor, and after the fire in the core had been put out. But at this point the decay heat and remaining fission reaction kept the core at more than 1200°C, causing it to melt through the concrete floors below the reactor.  And below the reactor were water tanks which contained 7,000 cubic meters of water (according to the TV show. If anyone has a real figure, I'd love to hear). When the lava of the melted core hit it, it would cause an enormous .  Finally, my question: About how large would this explosion have been? The character in the show says "2-4 megatons" (of TNT equivalent, I assume). I'm pretty sure this is absurd and impossible. But real estimates are hard to come by. Other sources vary wildly, some repeating the "megatons" idea, and others saying it would've "". This still seems crazy.  tl;dr:  I know a lot of it hinges on unknowns and the dynamics of the structures and materials involved, so I can simplify it to a constrained physics question:  Assuming 7,000 cubic meters of water instantly flashes to steam, how much potential energy is momentarily stored in that volume of steam occupying the same volume as the water did?  I don't know what to assume the temperature of the steam is. There were hundreds of tons of core material at temperatures near 1200°C, so worst case scenario you could assume all the steam becomes that temperature as the materials mix. Best case scenario, I guess we could assume normal atmospheric boiling point (100°C)?