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Sensei

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Everything posted by Sensei

  1. I think more web servers on the Internet have installed PHP module (standard LAMP). So when you will move project from home server to the world, it'll be slightly easier to find where to host it. If you're planning to (or already have) 24/7 running your own server, you might ignore it. What are you planning to write? What are your requirements for server-side scripting language?
  2. Air gas molecules in room temperature and pressure have average 340 m/s velocity. Arrangement of particles constantly changes. Say we have heating element in room, electrons passing through resistor heat it, and resistor is cooled down by air molecules, and accelerates them, they have higher velocity, higher kinetic energy. Then it spreads in whole room. Air molecule hits other air molecule, takes part of its kinetic energy. Repeat as many as you have molecules. Temperature near heating element will be the highest, and the further from it, the smaller temperature. Uniform temperature, uniform pressure, is just laboratory approximation, practically not existing in nature. Walk with precise thermometer (say +-0.1 C or more precision) in hand, and you will find gradient of temperature present around us. To have uniform temperature, to be able to precisely measure temperature in f.e. liquid scientists use magnetic stirrers.
  3. No. Trojan is application which pretends some useful features to user, and does open door to hacker behind, without his/her knowledge.
  4. It might be correlated with fact that in the past it was harder to get to noble degree course, than now. People who would fail to be accepted, now pass through.
  5. To have really good quality of ethanol, you should have everything made of lab glass (boro 3.3). Graham condenser, and preferably (but optional) Dephlegmator. So what if coffee maker will heat "wine" with ethanol, if you won't be able to condense it and turn back to liquid state.. Quart is 946.352946 mL (according to Google). It's plentiful of work actually to get it in such amount. From 800 mL (1 L distillation flask *) you will have at max 16%, 800 mL * 0.16 = 128 mL (today I was getting 80-90 mL with 70% = 63 mL). So to have 950 mL 100% (or rather 990 mL 96%) you need to process at minimum ~6 L of "wine".. More realistic value is 9 L. Single 800 mL distillation takes 2 hours. +30 m for cooling down and setting up next. You can't/shouldn't drink result of 1st distillation. It has 70%-85% typically (mine record is 92% from 1st) vol% of alcohol. There is needed to collect enough to perform 2nd, or even 3rd distillation, to have better/drinkable quality. *) distillation flask can't be filled to nominal volume. Just to 80% of nominal. During heating up volume will increase (you will be shocked how much). Everything what you need to have to distill alcohol you will find in lab glassware equipment shop for laboratories..
  6. Do you read book from 1895 "The Time Machine" by H.G. Wells https://en.wikipedia.org/wiki/The_Time_Machine or based on it films, like directed by author's great-grandson https://en.wikipedia.org/wiki/The_Time_Machine_(2002_film) Why the main character couldn't save his fiancée.. ?
  7. Do you want to emulate exactly the same CPU within the same CPU? Like emulate Intel on Intel machine? Or without such restrictions? Because 15 years old x86 CPU (Duron 1300 MHz) was emulating mine Amiga at speed it never had, literally hundred time faster. Amiga 500 has 7.14 MHz. 1300/7.14=182 times faster by frequency. But old CPUs had much slower instructions, f.e. division was the slowest instruction on Motorola 680x0, 140-158 cycles per div, 70 cycles per multiply, http://oldwww.nvg.ntnu.no/amiga/MC680x0_Sections/timstandard.HTML http://oldwww.nvg.ntnu.no/amiga/MC680x0_Sections/mc68000timing.HTML Current CPUs have it much more optimized, or even do couple instructions in single CPU cycle.
  8. Check whether PSU has correct voltages in the right pins. Starting after several tries (or after a while) suggest it might be cold solder joint, perhaps in PSU. If you have spare PSU, connect it to see whether there is difference.
  9. C'mon. These are vegetarians.. They don't need to eat adult. Lions and hyenas are concentrating on young buffalo and young antelope. Adult are harder to catch, run faster, are more powerful, have large horns that can kill them. Unlike their children. Crocodile-alike reptiles are eating mostly fishes. But when they attack land living animals, they're drowning them. It's much less energy consuming method of attack.
  10. The life cycle of a fly can range from days to years depending on species and conditions (as adult). http://www.orkin.com/flies/house-fly/ "The average life span for a house fly in the wild is less than one month."
  11. Only poorly written key-logger will be fooled this way. Because proper one, will check which window has focus using HWND GetFocus() https://msdn.microsoft.com/en-us/library/windows/desktop/ms646294(v=vs.85).aspx Key-logger/app also can use GetWindowText() to extract text already present in system-compatible GUI. https://msdn.microsoft.com/en-us/library/windows/desktop/ms633520(v=vs.85).aspx
  12. Fast dark matter would in couple hundred thousands years escape from galaxy such as Milky Way (which has diameter 100-180 kly)
  13. If paddles would have tiny holes, like strainer, it would work even better to create droplets. That's job for what we call 'pearls'. Tiny 2mm, 1mm or less size spherical pieces of glass. I have 250 pieces in my distillation flask. But for high temperature one can imagine using other material than glass for producing them.
  14. Any body is emitting photons. Energy of photons depends on temperature. The higher temperature, the more energy have emitted by it photons. That's why IR thermometers work from distance, without having to touch body. They analyze black body spectrum radiation of body. Devices used to heat houses with electricity or gas, doesn't matter, all emit IR and microwave photons. In not visible spectrum of light. Additionally they accelerate air gas particles. They have more kinetic energy, which is then transferred further in house by convection. https://en.wikipedia.org/wiki/Convective_heat_transfer https://en.wikipedia.org/wiki/Convection
  15. ROM is Read-Only Memory. Nothing magic at all. https://en.wikipedia.org/wiki/Read-only_memory It's like electronic version of CD/DVD. It's burned once in factory, and never can be changed. Rarely used these days. BIOS is typically in EPROM https://en.wikipedia.org/wiki/EPROM Which means Erasable-Programmable ROM. It requires significant actions to be erased, and reprogrammed. Read article. "The programming process is not electrically reversible. To erase the data stored in the array of transistors, ultraviolet light is directed onto the die." Or EEPROM https://en.wikipedia.org/wiki/EEPROM ROM/EPROM is the same in the same model of device. Or at least should be if virus didn't overwrite it (EPROM) with its code. Or you didn't upgrade BIOS by your self. ROM/EPROM can be read by anybody. If you would store there (in EPROM) data they would be the worst secure ever. Typically ROM/EPROM is not telling computer what it is. But it contains CPU program, which CPU is executing row by row.
  16. Try this in Windows scientific calculator (you might need enable option in menu, default is basic one): 10 power 0.5 = 3.1622776601683793319988935444327 Power ^2 it back, 10! Repeat it: 10 power 0.5 = 3.1622776601683793319988935444327 this time copy to clipboard (ctrl-c), Open new calculator application. Paste it, ctrl-v. Power ^2 = 9.9999999999999999999999999999955 In different OS-es it might work differently (different calculators). But that's what I have in Windows XP 32 bit at least. Later this day, I will check how it's in Windows 7 64 bit.
  17. Hi! Are you watching Air Crash Investigation on Discovery/National Geographic Channel.. ? I am always watching it, when have chance. Today was episode with airplane which lost front window, and captain pilot was sucked out on 5 km. Luckily stewards caught him in the right moment, when half of pilot was outside. 2rd pilot decrease altitude and landed so they could drag him back ASAP. He survived, although with several seriously broken and frozen parts of body. What was cause? Day prior accident, the front window was replaced. Engineer unscrew window, and decided to replace screws to brand new, instead of reusing old one. He went to storage, found exactly the same screw as he had in the hand, and asked grandpa-like storage manager about 90 similar 7D screws. But he told him that this model of airplane is using 8D screws. Engineer ignored this info, because 8D was not what he unscrew, and what was used already by airplane. He found 7D in storage and used them. Airplane was flying for 4 years with wrong screws without accident.. https://en.wikipedia.org/wiki/British_Airways_Flight_5390 Best Regards! ps. Who is flying tomorrow.. ?
  18. One of the best examples of spin IMHO is radioactivity. Say we have radioactive isotope with even quantity of protons and neutrons, f.e. Uranium-238 has 92 protons, and 146 neutrons. Both even. So it's composite boson with spin 0. It's decaying: U-238 -> Th-234 + He-4 + 4.267 MeV To Thorium-234, which has also spin 0. Helium-4 has also spin 0. So decay is immediate. And decay energy is split immediately to Th-234 and He-4. Appropriately to their masses to conserve both energy (E=mass of uranium-238 nucleus * c^2) and momentum (initially 0). But if radioactive isotope is fermion, it has fractional nucleus spin. f.e. Uranium-235 has 92 protons, and 143 neutrons. Spin 7/2 It's decaying: U-235 -> Th-231 + He-4 + 4.86 MeV Th-231 has 90 protons and 141 neutrons, spin 5/2. 7/2 dismatch 5/2 obviously. So there is needed gamma photon to be emitted by excited nucleus after decay.. Excited nucleus has more mass, and more total energy, than in ground state. So alpha particle is accelerated to smaller velocity, and has smaller kinetic energy, and smaller relativistic mass than like it would be in 1st case with U-238.
  19. This movement of daughter isotopes and products is final stage. This is decay energy, easily calculated as I am showing in article from my signature. Because you are not familiar with it. Say we have Uranium-238, with m0 = 238 g/6.022141*10^23 = 3.95208282e-22 g It's decaying to Thorium-234, and Helium-4. If you subtract rest-mass of U-238 from rest-mass of Th-234 and rest-mass of He-4, you will have missing-mass, in u units, multiply it by 931.494061 MeV and you will have decay energy in MeV units. m0 = 238.051 u m1 = 234.044 u m2 = 4.0026 u m0-m1-m2=238.051 u-234.044 u- 4.0026 u=0.0044 u 0.0044 u * 931.494061 MeV/u = ~4.1 MeV (actual value is Uranium-238 -> Thorium-234 + alpha + 4.26992 MeV) Basically rest-mass m0 of isotope prior decay, is equal to relativistic-mass of daughter isotope plus relativistic-mass of alpha particle (for composite Boson as is U-238).
  20. It doesn't matter. What matter, if it can predict everything what we know today.. Starting from spectral lines of Hydrogen, then to Deuterium, and Helium..
  21. How about radioactivity? [math]m(t)=\frac{m_0}{2^\frac{t}{t_{1/2}}}[/math] m0 - initial mass of radioactive isotope f.e.[math]^{14}_6C[/math] https://en.wikipedia.org/wiki/Carbon-14 t1/2 - half-life for [math]^{14}_6C[/math] is 5730 years. so after 5730 years we find that [math]m =\frac{1}{2}m_0[/math] There is no motion involved in this calc. We find animal body, carbon ore, ancient artifact, we know how much of Carbon-14 it should have, and measure what is actually mass of this isotope, and finding out how much of time was needed to decay isotope to have such effect. Reverse of above equation. Instead of measuring mass m at time t, measure time t from known m0 and m and t1/2.. Radioactive dating article: https://en.wikipedia.org/wiki/Radiometric_dating
  22. One can move in +1m in X axis in f.e. 1 second, or 2 seconds, or 1 hour, or +1m Y axis in 1 second, or 2 seconds, or +1m Z axis in 1 second, or 2 seconds, (or any other distance d, less than c, in time less than t=d/c) Then how can you say "and thus no fourth dimension is needed to explain it.".. ?
  23. Sensei

    Crude Oil

    How is called process in which vodka is produced?
  24. Very cool design. +1 It's seamless approach to solution how to mount and power it.
  25. HTTP server does not know what is in layer above it. Doesn't have any idea about HTML. One can have list of image files, or any other files for example, that have nothing to do with HTML. It's as easy to make HTTP server replying HTML as any other file type. According to https://en.wikipedia.org/wiki/CERN_httpd CERN HTTPD was written on NextSTEP, later ported to Unix. They're using HTTP ports/protocols to be as invisible/hard to detect transmissions as possible. BTW, scienceforums.net is on nginx..
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