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Everything posted by Sensei

  1. Surprising attention to the details by movie makers.. Parallax is widely used to measure distance to stars in this galaxy.. https://en.m.wikipedia.org/wiki/Parallax
  2. Sensei


    With normal human acceptable 1g acceleration, spaceship can reach near speed of light in one year. https://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration "From the planetary frame of reference, the ship's speed will appear to be limited by the speed of light—it can approach the speed of light, but never reach it. If a ship is using 1 g constant acceleration, it will appear to get near the speed of light in about a year, and have traveled about half a light year in distance. For the middle of the journey the ship's speed will be roughly the speed of light, and it will slow down again to zero over a year at the end of the journey."
  3. Henrietta Lacks's immortalised cancer cell line was an important breakthrough.. https://en.m.wikipedia.org/wiki/Henrietta_Lacks Evolution of bacteria gaining resistance to vaccines recorded by camera on timelapse video: At the end of the video there are showed new branches of bacteria highlighted with various colors. Researcher can take samples of two or more such branches and compare differences in DNA between them.
  4. How about different approach: instead of searching for a way to increase power production, search for a way to reduce current power usage? Households in hotter regions of the Earth significant amount of electrical energy use on air conditioning and refrigeration of food. Households in the colder regions of the Earth use significant amounts of energy to heat homes during the winter. Decrease of power usage for TV and computers has been already done by migration to LCD/LED/OLED and to laptops (from power consuming CRT and plasma). So, limit energy used for air conditioning and refrigeration, and you will get the same effect as increased power production, with increased demand for power. See an example of some e-books smart displays. Instead of using power for continuous sustaining display, energy is used only for switching different pixels between one page and another page. https://en.wikipedia.org/wiki/Electronic_paper Personally, I am for turning streets to one large solar panels new generation with built-in electromagnets. They could produce energy and immediately transport it to vehicles flying slightly above them due to magnetic repulsion between streets and vehicles. Mass of cars would be minimal without full size tank nor full size accumulators. Without friction with road, energy spend on acceleration would be much smaller than now. To decelerate/brake there could be used KERS or similar system converting kinetic energy to electrical energy.
  5. What you are searching for is called 3d scanner. https://en.wikipedia.org/wiki/3D_scanning https://www.google.com/search?q=3d+scanner Click this: https://youtu.be/flIBTT-KfmM?t=358 (start at 6 minute to skip ads) But 3D scanner, like human, is only able to see, and recreate as 3D object, what is visible from the all sides from outside of the real object. True 3D scanning, with internal (perhaps complex) structure, would require x-ray machine, with rotation of object, which would recreate slices with the all details (like holes inside).
  6. Generally good +1. With one yet another digit of precision it is 0.2505 mol With one more digit it will be 1.50852*10^23, and 3.017*10^23 But generally good answer.
  7. Number of [math]\pi[/math] is 10[math]_{\pi}[/math], if we will use base-[math]\pi[/math] numeral system..
  8. Nonsense. Heated metal melts and oxidize if there is present air with Oxygen 1. If you apply voltage counted in millions of volts, current passing through conductor unprepared (not designed) for such high voltages, will within milliseconds or microseconds reach melting temperature and burn wire breaking circuit. That happens in majority of electric and electronic devices. It is just a matter of applied voltage. e.g. fan is stopping working in computer power supply unit, which is transforming from 230 V/110 V AC to 12V/5V DC. It is starting giving larger voltage than it should e.g. 13-15 V, and motherboard, CPU and peripheral devices designed for 12V are damaged. Materials have various resistivity [Ohm*m]. Multiplied by area [m^2] of object and divided by length of object [m], gives resistance in Ohms. Conductors have very small resistivity thus very small resistance. Insulators have extremely large resistivity thus very large resistance. But neither resistivity nor resistance nor impedance is constant. It varies as a function of temperature and pressure. There are insulators that start conducting after heating them to the right temperatures under very large pressures. And there are conductors (at room temperature conductors!), which after cooling down to very low temperatures (below 90 K), become superconductors, as measured resistance is 0 (or close to 0). Drop of voltage on superconductor is indistinguishable from 0 V. Current passing throw conductor is heating it. As I mentioned earlier resistivity/resistance depends on temperature. Conductor which is heated due to electrons colliding with its atoms is worse resistor. Wire is also resistor. But with extremely low area and very large length 2) Heated metal melts and oxidize if there is present air with Oxygen1. 1) Therefor the first lightbulbs had vacuum, later replaced by inert gas at low pressure. 2) Imagine wire conductor with resistivity 1 ohm * m and 1 mm diameter and 1 meter long. R=p*A/l = 1 [ohm *m] * PI * (0.0005[m])^2 / 1[m] = 7.854e-7 ohm. Drop of voltage on such element will be extremely small. Heated metals expand, therefor cross-section area A, diameter and length of wire, will be changing as function of temperature.
  9. That's still wrong.. Actually wronger than previous..
  10. In one line you entered the correct value, and one line later you entered wrong value.. Recheck them.
  11. .NET Framework String class implementation: https://docs.microsoft.com/en-us/dotnet/api/system.string.intern?view=netframework-4.8 "The common language runtime conserves string storage by maintaining a table, called the intern pool, that contains a single reference to each unique literal string declared or created programmatically in your program. Consequently, an instance of a literal string with a particular value only exists once in the system."
  12. Isn't this algorithm with cutoff like self-fulfilling prophecy.. ?
  13. Explosives, including dynamite, are creating blast wave (which can be seen on fast recording cameras), later comes debris of elements that were on path of explosion. Shock wave, blast wave arrives the first, later material debris, and they together cause injury in humans and destroy infrastructure. e.g. explosive material is put to inside of grenade. What kills people around explosion? Small metal debris of grenade, not explosive material directly. So, no, you did not invent a thing which will help you survive an explosion. Unfortunately.. So, stop spreading this nonsense.
  14. When someone is talking about invention of agriculture is really thinking about seeding and harvesting grain. It is inedible raw! Human had first to figure out how to process grain by blending and mixing it with water and placing on hot stone heated by fire to make pancakes to make it edible. It is not so straight forward and obvious. Attempt of eating unknown plants might end up in death if they are poisonous. Somebody had to be the first one to try every currently known plants, including toxic and poisonous. Knowledge which plants are edible is shared by older generations. Easy to lose knowledge in the world without even paper..
  15. You're going, like I in the first source code, from 1, and increasing loop counter. Try going from half of range, and then decreasing by 1, till it's bigger than 0. BTW, we can see your code gave wrong answers, e.g. 1.001: 33033 33000 It should be 1001/1000, isn't?
  16. You cannot enter numbers like this to computer.. Decimal number parser (and entire decimal number C++ class) would have to be modified to support parenthesis, and then keep number as a p/q instead of regular number. It has (infinitely) repeating decimal period. 1.(210526315789473684) https://en.wikipedia.org/wiki/Repeating_decimal Other examples: 1/3 = 0.33333(3) 4/3 = 1.33333(3) Check section "Converting repeating decimals to fractions" in the above article.
  17. I made little brute-force algorithm for you. Executable is in Release folder. // RationalSeeker v1.0.1 (c) 2019 by Sensei : main project file. #include "stdafx.h" using namespace System; int main(array<System::String ^> ^args) { if( args->Length == 1 ) { try { String ^arg = args[ 0 ]; Decimal rational = Decimal::Parse( arg ); Console::WriteLine( L"Rational " + rational ); Decimal temp_rational = rational; Int64 temp = 1; while( Math::Floor( temp_rational ) != temp_rational ) { temp_rational *= 10; temp *= 10; } Int64 integer = (Int64) temp_rational; Console::WriteLine( L"Integer " + integer ); Int64 half = integer / 2; for( Int64 i = 1; i < half; i++ ) { if( ( ( integer % i ) == 0 ) && ( ( temp % i ) == 0 ) ) { Int64 numerator = integer / i; Int64 denominator = temp / i; Console::WriteLine( numerator+ L"/" + denominator + L"=" + rational ); //break; } } } catch( Exception ^e ) { Console::Error->WriteLine( e->ToString() ); } } else { Console::Error->WriteLine( L"Required parameter missing!" ); } return 0; } It first get rid of fractional part by multiplication by 10 in the loop. Then goes in the second loop through the all numbers from 1 to half of integer (it could go through the all primes including 1 instead, but first we would have to have array of the all primes). Edit: fixed variable names, and decreased archive size considerably.. RationalSeeker.zip ps. If you want to find it faster, replace: for( Int64 i = 1; i < half; i++ ) { by for( Int64 i = half; i > 0; i-- ) {
  18. ..there is infinite quantity of answers.. 102/100 = 1.02 204/200 = 1.02 306/300 = 1.02 [...] 1020/1000 = 1.02 etc. etc.
  19. Mass of what? Mass of small things is measured on weigh. Mass of uniform things is calculated from average density muliplied by volume of an object. e.g. mass of the all oceans can be calculated from volume, obtained from depth maps, muliplied by density 1 kg/L. Mass of astronomical objects like planets is calculated from gravitational acceleration of an object. Mass of macroscopic objects is sum of masses of constituents. Measure mass of single average grain of sand, calculate volume of a beach, and you will know average quantity of grains. The same is with atoms. Therefore we can convert mass to moles in chemistry.
  20. There are studies measuring correlation of results in IQ tests of differently related siblings. Single egg twins, two eggs twins and regular siblings. https://www.mun.ca/biology/scarr/IQ_Correlations.html
  21. There is no "intelligence gene", but there are genes responsible of control of how well brain is feed by nutrients and controlling oxygenation of the brain. https://www.google.com/search?q=oxygenation+of+brain+intelligence Nutrition of a women in the prenatal phase, nutrition of a newborn child and later development of human being has influence of intelligence. In countries (or regions of the Earth) where there is food shortage, due to costs and availability, people have worse average IQ. People to become intelligent require stimulation of the brain, during childhood, and later in life. Again, it is easier for people and families who don't fight every day to survive.
  22. Because it is diluted to ~10%. In ready dish even more diluted. You also did not have severe burns from hydrochloric acid which is in your stomach. Apart from bases, https://en.wikipedia.org/wiki/Base_(chemistry) Hydrogen Peroxide perhaps? https://en.wikipedia.org/wiki/Hydrogen_peroxide#Safety "In high concentrations, hydrogen peroxide is an aggressive oxidizer and will corrode many materials, including human skin. In the presence of a reducing agent, high concentrations of H2O2 will react violently."
  23. Yeah. Burst of neutrinos from supernova will come the first. Then red alarm for Hubble telescope...
  24. It is acid and OP said: "I am not necessarily interested in things which would cause severe burns like acid".
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