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Sensei

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Everything posted by Sensei

  1. Do you know that air molecules have speed approximately 340 m/s.. ? Fans are widely used to cool down electronic equipment and devices e.g. CPU.. which has more than 70-80 C during operation.. There is no (significant) evaporation from surface of CPU (as it has no more water than is initially in air).. still fan is cooling it.. @dstebbins Particle hitting at target can be scattered/reflected and having more kinetic energy than it used to have prior collision (taking part of energy of body which has been hit). Particle hitting at target can give part of it's kinetic energy to body and excite it. But soon induced emission will happen and photon with higher energy will be emitted taking body energy with it.
  2. Fermi Paradox finally solved: extraterrestrial intelligent life forms are not revealing to extreme right wing members because they don't want to become their meal..
  3. Cold beverages are refreshing.. in the appropriate moments.. I think so your question miss some details. If you would be on Alaska/Arctic/Antarctic in the middle of winter.. you certainly should prefer hot beverages...
  4. As I said earlier, everybody can make kefir, in just few hours from milk, and have their vitamin D nutrient, even if they're lactose intolerant.. They just have to have knowledge that fermented milk has no lactose (or tiny amount of lactose) (and knowledge what is lactose.. and what is lactose intolerance at all..)... It's much easier than migrate back to Africa, or so, don't you think so.. ? This is a very similar case as in the case of sailors, and a deficiency of vitamin C causing scurvy. After they realized that citruses are healing them, they spread plant on the entire globe and used it. There was just needed knowledge "do you have scurvy? eat citrus".. A bit of history: "James Lind (...) he developed the theory that citrus fruits cured scurvy. " https://en.wikipedia.org/wiki/James_Lind
  5. As I said earlier, after hypothetical collapse of civilization, the most valuable thing will be knowledge. If they have just gigantic pantry, but have no duplicate of wikipedia (also in printed version the most important things like physics, chemistry, biology, etc.), they're not really prepared..
  6. mT = mili Tesla unit KGs = Kilo Gauss unit KA/m = Kilo Ampere per meter unit KJ/m3 = Kilo Joules per m^3 unit KOe = Kilo Oersted
  7. Oh, no.. we have one fantasy universe already in which D.T. became POTUS...
  8. I assume you want it to be transparent/opaque in visible spectrum (so it will still be visible in IR/MW spectrum). Even if you would find compound which reacts to UV light in the way you're interested, there still would be problem with refractive index not equal to 1.0. When light is entering medium which has different refractive index than air, beam of light is bended. e.g. we can see glass because of deformation of image behind it.. Check this video: Why it has to react to UV light? Is it necessary? There are compounds which change light polarization when they're exposed to external electric and magnetic fields. Two such layers rotated 90 degrees (or one layer + polarization filter layer) and there is electronically controlled opaque/transparent window. You can make crystal which is opaque and then turn transparent when you turn on/off electromagnet. Did you hear about liquid crystals? https://en.wikipedia.org/wiki/Liquid_crystal
  9. Really? I mean, really!? He was mocking.. Politicians know very little about computers, and even less about how to program computers and how to make websites.. Any serious webmaster/computer programmer should know that there are practically the only three ways to store session id (but some custom non-standard ways could be developed in e.g. JavaScript/AJAX). Cookies (readable by $_COOKIE[] array in PHP), query string (URI) (readable by $_GET[] array in PHP), and third one which should not be even mentioned as the last reliable.. Cookies is THE BEST out of these three methods! Practically any website which is allowing user to log in to their account must use cookies (as the most reliable way to store session id of currently logged user). In old times, '80 years, lame webmasters were using 2nd method (session id inside of query string). But if such website has links to 3rd party websites, session id will be put to inside of Referer parameter in HTTP-Request (and linked website programmer will be able to read it using e.g. $_SERVER[ 'HTTP_REFERER' ] in PHP: <?php if( isset( $_GET[ 'Index' ] ) ) $index = $_GET[ 'Index' ]; else $index = 0; $index++; if( isset( $_SERVER[ 'HTTP_REFERER' ] ) ) printf( "Referer: " . $_SERVER[ 'HTTP_REFERER' ] . "<br />\r\n" ); printf( "<a href=\"test.php?Index=$index\">Click here (again!)</a><br />\r\n" ); ?> I showed it on the above little program that you can run on your Apache server or other WWW server. After clicking link you will see that second linked website is receiving "index"... If webmaster is using session-id in similar way in query string, it's passed to any linked 3rd party website (and nobody knows what happen with it later), and somebody can in the real-time pretend he/she is logged user instead of the real user, from 3rd party machine.. In the case of cookies this problem does not exist. There are other problems (e.g. availability of cookies inside of sub-domains of the main domain, if they're incorrectly set up). Cookies are essential for properly store session id of the currently logged user (e.g. user of this forum). Such regulation asking for whether user allows using cookies, is kinda like question, whether they want to breath at all.. Can you live without breathing? No. Can you log in to your user account when website is using cookies to store session id? No.. That's because information that you allowed website to use cookies, is stored in cookies (i.e. local data on computer, that's the only data send to website while visiting it).
  10. Decimal system is just one of infinite quantity of numeral systems.. Somebody can write [math]\pi[/math] using e.g. binary system. At least couple the most significant digits of it. And it will be series of zeros and ones: %11.00100100001 Numeral system does not even have to use integer base. https://en.wikipedia.org/wiki/Non-integer_representation There are base-e, base-[math]\pi[/math], base-[math]\sqrt{2}[/math] numeral systems.
  11. Mass spectrometry could be used to literally separate two isotopes in macroscopic amounts... https://en.wikipedia.org/wiki/Calutron ..unfortunately it was used in the most disgusting accident of this world.. to create nuclear weapons used to attack Hiroshima and Nagasaki..
  12. To measure elementary charge ("e") there are used x-ray photons fired at drop of oil, to ionize it ("eject electron"), between two electrostatically charged pieces of metals.. https://en.wikipedia.org/wiki/Oil_drop_experiment
  13. What if studiot is just AI/AGI on my "hard disk".. ? How would you define "existence".. ? ps. Imagine temptation of shutting/not shutting down D.T. or V.P....
  14. You must be on heavy hangover.. in the part of my message that you "accidentally" cut out in your quote, I said to use thermistor in electronic breadboard with Arduino ("Arduino temperature sensor"), to precisely control temperature.. ^^^^ result of googling for "arduino temperature sensor"...
  15. Charge of particle is intrinsic essential property..
  16. Two thousands years ago, you would have wife and awaiting children at such age.. Surround test tube by aluminum foil, place precise thermometer inside. The easiest would be to use Arduino, with temperature sensor, with custom made program which will read temperature and keep steady temperature..
  17. Two thousands years ago, you would have wife and awaiting children at such age.. Surround test tube by aluminum foil, place precise thermometer inside. The easiest would be to use Arduino, with temperature sensor, with custom made program which will read temperature and keep steady temperature..
  18. Electromagnetism is split to electrostatic forces and magnetic forces. Sometimes they overlap in specific experiment. Charged particles are creators of electric field around them, and moving charged particles are creators of magnetic field around them. Unpaired electrons are creators of magnetic field around them. Particles with mass and energy are creators of gravitational field around them. Strengths of forces diminish with distance differently! (in curved space/spacetime such diminishing with distance (e.g. inverse square law) would be extremely complicated) There is experiment in which electrostatic forces and gravitational forces overlap. It's oil drop experiment.
  19. Entire world in day at noon is saturated ("flood") by tremendous high frequency photons with 428 THz ... 749 THz.. ps. Saturation means that nothing can be put in anymore.. If world would be saturated by photons, everything would melt, and then turn state of the matter, and then change to plasma..
  20. The more appropriate mathematical naming conventions: x is called exponent. https://en.wikipedia.org/wiki/Exponentiation 32 * (1/2)^x = 1 (1/2)^x = 1/32 2^-x = 1/32 2^-x = 32^-1 2^x = 32 2^5 = 32 log2(32)=5
  21. Did you have logarithms at school? e.g. if you would like to calculate number of the all possible values of the single byte you should use 2^8 = 256. reverse of it is log2(256)=8 e.g. 32 bit unsigned integer: 2^32 = 4294967296, log2(4294967296) = 32 ps. You can use Wolfram Alpha to calculate such things e.g. http://www.wolframalpha.com/input/?i=log2(32)
  22. Migration will be caused by overpopulation plus global warming. Too hot regions of planet for agricultural production in the future, will cause exodus from Africa to colder regions of the planet. Eventual migration from North America can be caused by eruption of Yellowstone Caldera.
  23. Domestication of cattle happened just relatively recently, approximately 10,500 years ago. There was not enough time for natural selection. Also, intolerance does not kill, so even if tolerance would be developed in some people, people with intolerance would still survive, still spreading their genes, and mixing with people with tolerance (disallowing tolerance to lactose in genes to prevail, and becoming dominant in population). There is also very easy way to turn milk to become drinkable by people with intolerance - simply make kefir. Put spoon of old kefir to container with fresh milk and wait couple hours. https://en.wikipedia.org/wiki/Kefir "As a result of the fermentation, very little lactose remains in kefir. People with lactose intolerance are able to tolerate kefir, provided the number of live bacteria present in this beverage consumed is high enough (i.e., fermentation has proceeded for adequate time). It has also been shown that fermented milk products have a slower transit time than milk, which may further improve lactose digestion.[11]"
  24. Maybe you would like to rephrase it to "does quantum physics in lab operate on too large energies to be able to detect so subtle things like gravity?"..
  25. Depends on the particle. Neutrinos don't. Google for "Photon-neutrino scattering".. Google for "Photon-neutrino scattering site:cern.ch" (to limit just to CERN). 21k articles.
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