Sensei

There is few isotopes which decay exclusively by neutron emission. https://en.wikipedia.org/wiki/Neutron_emission Hydrogen-4 Hydrogen-5 Hydrogen-6 Hydrogen-7 Helium-5 Helium-7 Helium-9 Helium-10

I cannot believe some science forum members voted +2 your post... after he revealed he molested women (and have been recorded on video) putting hands in their pussies etc. etc. which were not his lovers...

Typical DC does not have frequency, does not have pulses.. It's constant voltage with constant amperage (+- some tolerance). If on one end of wire will be appearing positive charge, and then in the next stage of phase, there will appear negative charge, it's AC. What you're interested is delta between the most extreme levels. 1000 Volts is way too small for air at STP. You should use Cockcroft-Walton generator to generate many thousands of volts (cost less than $10), if you don't have vacuum pump (cost >= $300).. This is what you can have with 50 kV:

WiFi router could be compromised. If it's internally Linux/unix-based (not plain hardware just with ROM), somebody can install something on it that will analyze every packet and send them to him. Colleague hacked his own WiFi router and had terrible slow down of Internet. He had to remove his own changes in router software. Such hacked router can redirect DNS server queries to fake DNS server and while going to any website ending up on hackers websites that just transmit data from/to true one.

I don't have book. You also didn't attach anything to your post. But Rubidium 87 has very large half-life 49.23 billion years. If g is fraction of abundance, g=0.063 (6.3%) of Rubidium 87 decayed to Strontium 87. Sr-87 will have abundance in the sample rock 6.3%, and Rb-87 will have abundance in the rock 100%-6.3% = 93.7%. Measured by mass spectrometer, or using chemical reaction unique to these elements, to separate them, and being able measure their mass and abundance. Rubidium compounds readily (explosively) react with water (RbOH) and are very good soluble in water (similar like Na,K,Cs), while Strontium compounds are barely soluble in water (Sr(OH)2) (like Mg,Ca). The only decay mode of Rb-87 is by beta decay minus to Sr-87: Rubidium-87 -> Strontium-87 + e- + Ve + 0.282271 MeV You can make Spread sheet in Open Office, or Excel, with normal half-life equation, like I did here: Rb 87 Decay.zip And you will see data with 93.7% of Rb-87 and 6.3% of Sr-87 is between 4.5 bln y to 4.8 bln y. Load file in OpenOffice and decrease step in A3 field from 0.15 to lower value, and Edit > Fill > Down, for better precision. ps. Why it's in Mathematics, not Physics section.. ?

Oi, snap! Thanks, I wasn't paying attention to the conversion last night. The numbers are corrected now. So the 13.6eV number is in energy, and energy is equal to mass times the speed of light squared. The weight in a mass measurement is irrelevant because of this. 13.6 eV is energy that's missing.. Electric neutral Hydrogen (proton and electron bound together) has smaller mass-energy than free proton and free electron. Hydrogen release 13.6 eV, as photons, in discharge tube filled by Hydrogen gas, creating spectral lines.. Don't you know how to calculate these lines? That's XIX century knowledge..

21st century "Meccano"-on-steroids-version (aka build your own iPhone in China) Quite hilarious.

Wood watermill and windmill, earlier than industrial revolution, are examples of automatization of human work as well.

Tasks that can be easily automated, are typically hated by people having to do them. They are dreaming about better job.. Imagine work in warehouse: Would you like to work in warehouse?8-12 hours per day scan box, move to the right place on the feet and put on the right shelf.. ? Day by day, the same stupefying job. If I would have such job in warehouse, I would invent robot that would do it for me instead, and just remotely monitor what he is doing. I think so human should do jobs that they at least like, if not, love. Take for example scientists. If they would be fired from university, in the majority of cases, they would work for free at home. Especially theoretical physicists and mathematicians, working on their own theories, trying to discover something.

I tried reproducing your calcs on piece of paper, and getting 0.282 mm radius, and then 0.094 mm^3 volume of drop. Shouldn't you multiply volume by density 13.5 g/cm^3 = 0.0135 g/mm^3 to get mass of sphere? I am getting mass of drop (sphere) 0.00127 g. Or I misunderstood what you meant by 0.1g?

msetlur, you're making stuff up on the spot... If you have radioactive isotope with rest-mass m0 it has energy [math]E_0=m_0 c^2[/math] (let's simplify example to isotope with even Z protons and even N neutrons, because they have all 0 nuclear spin) When it decays by alpha decay, It decays to daughter isotope Z-2,N-2,A-4 and Helium-4 nucleus (alpha particle), with Z=2,N=2,A=4. Daughter isotope has rest-mass m1, therefor in rest-frame it has energy [math]E_1=m_1 c^2[/math] Helium-4 nucleus (alpha particle) has rest-mass m2 and energy [math]E_2=m_2 c^2[/math] But after decay, they're accelerated. Therefor equation of energy will be: [math]E_1=m_1 c^2*\gamma_1[/math] [math]E_2=m_2 c^2*\gamma_2[/math] [math]\gamma_1 = \frac{1}{\sqrt{1-\frac{v_1^2}{c^2}}}[/math] [math]\gamma_2 = \frac{1}{\sqrt{1-\frac{v_2^2}{c^2}}}[/math] Giving finally [math]E_0=E_1+E_2[/math] [math]m_0 c^2 = m_1 c^2*\gamma_1 + m_2 c^2*\gamma_2[/math] Basically rest-mass of initial particle prior decay is equal to relativistic-masses of newly created particles. [math]m_0 = m_1 *\gamma_1 + m_2 *\gamma_2[/math] Alpha decay recorded on video in Cloud Chamber: The longer trace, the more kinetic energy had alpha particle. So, when using different isotopes, you can see their traces will be different length. And compare them. Gammas will be when nuclear spin mismatch between parent isotope and daughter isotope. When Z or N are odd, typically. Kinetic energy of alpha will be decreased by energy released by gammas.

This is a simple mathematical equation that can help to answer the question: - how many people live in the world? f.e. 7 billion - how long does an average person live? f.e. 70 years 70y * 365.25 = approximately 26,000 days of life per person. 7 bln / 26,000 days = approximately 270,000 people would have to fly to cosmos daily to all of them being at least once in cosmos. Do you find it realistic?

I can't believe my own eyes... Did you read entire my post... ?

You're missing the point.. Now everybody with idea of device, and having more than 500 usd+ can simply make thing using 3D printer (now everybody should have 3D printer or ready access to it!) Lego/Meccano has to learn KIDS how devices are made. So they can see and learn internals.

This Porsche looks to me very sophisticated. Elements can be used just once in the one right place. The whole LEGO technic, true one, must be universal. Once you build device from the box, other time, completely different device, so elements must be universal, or will be useless for other projects. Where is Meccano? https://en.wikipedia.org/wiki/Meccano James May in Toy Stories, built Meccano bike, and Meccano bridge: https://www.youtube.com/results?search_query=james+may+meccano+motorbike+full+episode https://www.youtube.com/results?search_query=james+may+meccano+bridge For kid, engineer-to-be (robotics etc), metal Meccano with electric motor engines, means being in heaven. The next essential step will be Arduino, Raspberry Pi, and sending orders to device by wire/wifi from laptop/desktop/through internet..

Obviously you can make tree in Java. Like in any OO environment. You just have to make class with left branch of tree, and right branch of tree. If it's binary tree. Eventually containing information whether it's 'leaf' or 'branch', and eventually containing quantity of elements, or other things related to project. f.e. 3D KD-Tree has axis integer and median float/double. There are also trees with other quantity of branches or leafs. The most common Octree.

Lego Technic should be the most favorite toy of the world. But price disallows. Looks like a lot of fun..

Too little data. You didn't tell us which curve type you're interested in. There is Bezier curve. https://en.wikipedia.org/wiki/Bézier_curve There is B-Spline curve. https://en.wikipedia.org/wiki/B-spline There is Catmull-Rom curve.. https://en.wikipedia.org/wiki/Cubic_Hermite_spline Sounds like homework. See Xerxes note.

Somebody who would like to run Android SDK, with emulator of mobile phone device, must have 64 bit CPU, which has virtualization feature, and Windows 7+ 64 bit (this is the smallest problem). It's nearly impossible to write and test any Java application for Android, on 32 bit CPU, because emulator of modern smartphone needs a few GB of memory to be run. With 512 MB or 1 GB it'll be crawling. Without virtualization emulator won't even start for 2 years IIRC. Emulator has also some requirements for the gfx card used. Somebody who would like to be good at security must be versatile in programming smartphone, as they're attacked the most these days, and once they're intercepted, they can be used for further attacks in intranet. CPU should be as fast as possible, to have good emulator speed.

Photons have property called energy. Energy of single photon is: E=h*f where h is Planck constant 6.62607*10^-34 J*s and f is frequency in Hz (s^-1). Frequency has equation f=c/wavelength or f=1/T Therefor we can substitute: E=h*c/wavelength E=h/T Photons with small energy are called radio waves, photons with slightly higher energy are called microwaves, then infrared photons (IR), then visible light, then ultraviolet (UV), then x-rays and gamma ray photons, with the largest energy. https://en.wikipedia.org/wiki/Electromagnetic_spectrum Matter (or antimatter) is emitting photons in the all directions (inverse-square law), energies of these photons correspond to temperature of object. It's called black body radiation. Even if human don't see IR or microwaves, objects are emitting them, and electronic devices can detect them and record on video. f.e. Some mediums/materials are transparent to one photon energy/frequency/wavelength, and opaque to other photon energy. Photons can be also reflected, refracted or absorbed by medium. X-rays photons are emitted by excited atom electrons. Gamma photons are emitted by f.e. excited atom nucleus, during annihilation, during decay of unstable particles and isotopes.

You can't be serious with this "source"...

We should start from the fact that speed of sound is not constant, and depends on medium (f.e. speed of sound is much higher in solids/liquids than in gases), and variable properties of medium (f.e. pressure/temperature). You can actually hear how speed of sound changes with altitude on this video taken from starting homemade rocket: Start at 2m15s

GetDIBits() function doesn't allow to specify which part of bitmap will be captured (just start row and height). Programmer would have to make duplicate of device context (HDC) and/or bitmap (HBITMAP) first. It takes HDC as argument (which will be returned by, enumeration of windows (EnumWindows()) present in the desktop, and then GetDC() (or copy of it)) So it'll be already truncated to size of HWND window it belongs to (from screen-shot OP provided, playfield to analyze is significant area of window). OCR? Optical Character Recognition? There is no characters to recognize in Tetris game playfield.. Just blocks with different colors. Once you have bitmap or device context, one can use GetPixel() https://msdn.microsoft.com/en-us/library/windows/desktop/dd144909(v=vs.85).aspx to read pixel color, as COLORREF structure. If it's black, no block is present in specified location.

It's possible to make such application, which will be periodically screen-capturing specified window, and then analyze pixel by pixel, received bitmap. In C/C++, in Windows application, you can use GetDIBits function https://msdn.microsoft.com/en-us/library/windows/desktop/dd144879(v=vs.85).aspx

Did you try eBay? http://www.ebay.com/bhp/hydro-electric How about googling for "Tesla Water turbine"?