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Hi, Why the alcohol thermometer is less precise than the mercury one? If I remember correctly, it is because the thermal expansion coefficient of alcohol is not constant, but I am not sure. Thank you for your time. Regards, ORF

Hi, I have measured a set of V-I values, and I have to provide the value of the resistance. I have used ac and dc current. The circuit was quite simple: power supply -> ammeter -> resistance -> [power supply] wave generator -> ammeter -> resistance -> [wave generator] Voltage was measured...

Summary: If a forest is scorched, after a while it will regrow(wont it?); but if it is periodically burnt to ashes, could it eventually die? (as a ecosystem) What is the time-scales in order to recover a forest after a blaze? Hello, If a forest is scorched, after a while it will regrow (wont...

Hello all, in the near future, open science (open science != open access) will be real in Europe. It is a bit controversial, specially in some fields. What do you think about it? As far as I know, researchers in Astronomy exploit it successfully. But I am not sure about the impact of open...

Hello, because of the "kinetic isotopic effect", https://en.m.wikipedia.org/wiki/Kinetic_isotope_effect can the ratio of the common isotopes of N, C, P, H, O, S determine the position of an individual in the food chain? (eg, have carnivore animals higher proportion of light isotopes than...

Hello, I was told every country needs a constant electricity production source (like coal or nuclear powerplants), and up to some proportion, renewable sources (photovoltaics, hydro, wind turbines, etc). So, my question is: what limits the amount of renewable sources? (the grid, storage...?)...

Hello, I have pure KCl, but its natural radioactivity is low. I would like to increase it at least by a factor of 10. Is there any simple way (diy) for enriching the natural KCl in 40K? Alternatively, is there a compound with higher concentration of potassium (in volume) than KCl, and that you...

Hello, The explanation for this, min 0:54 is that you have Fe2O3 in the match head, and after burning it, pure iron is obtained 2 Fe2O3 + 3 C -> 2 Fe + 3 CO2 I think the chemical explanation is fine, but I don't understand why Fe2O3 is added (as colorant, if the red phosphorus is already...

Hello, is std::bind reentrant? If not, the bound values have to been stored somewhere? Thank you for your time. Regards, ORF https://en.wikipedia.org/wiki/Reentrancy_(computing)

Hello, I don't know how to compute that number, but probably is a kind of reference value... Q: How many ion-pairs are there in normal conditions* in the air? (This is not homework, it is just out of curiosity.) Thank you for your time. Regards, ORF * 1 atm, 300K.

Hello I am not sure about what should be the best format for a input text file. I think before start shooting in the dark, it's better to ask experienced people. The (C++) program has to create a net. The nodes will be defined in a input text file. For convenience, the net will be a bunch of...

Hello This is the video: Question: why does the ant seem to be trapped by the ink circle? Thank you for your time. Regards, ORF

Hello In nuclear physics, the mass excess is caused by the nuclear binding energy. Question: is there any macroscopic example where the "mass excess" is non-negligible? Thank you for your time. Regards.

hello I needed to count the number of processes (with the same name). I found that this bash script works, #!/bin/bash exit $(ps cax | grep firefox | wc -l); and the exit value can be caught by this code #include <stdlib.h> // sytem #include <iostream> // std::cout, std::endl int main() {...

Hello How the surface tension is measured for molten metals? I have heard about the sessile drop, but it seems to be a very inaccurate method... Thank you for your time. Regards.

Hello I have used a random number generator to create a list of uniformly random numbers, between 0 and 1. The usual check that I do is sorting the list, and histograming the difference between the following and the previous one. The shape of the histogram should follow an negative...

Hello I have read this article about why doesn't the stomach digest itself https://www.scientificamerican.com/article/why-dont-our-digestive-ac/ but also during the digestion along the small intestine, there are enzymes. How does the small intestine defend against these enzymes? ( I suppose...

Hello I found this video on YouTube, It seems that most of the counts are noise of the PMT... Thank you for your time. Regards.

Hello During a simulation of light in gamma-scintillator interaction, it seems that there are a lot of Cerenkov photons. I don't know their contribution to the final intensity (it will need a long time to compute it). The textbooks usually say that the gamma ray will produce secondary...

Hello I found some webs, but I would like to know a bit more https://en.wikipedia.org/wiki/Electroejaculation http://www.ivf-infertility.com/ivf/ejaculation.php "is to directly stimulate the seminal vesicles." I don't know how exactly works in "natural conditions", but it seems to me that the...

Hello Does radioactivity help fungi to grow? The article is 10 years old, I do not know if there is something newer... https://www.scientificamerican.com/article/radiation-helps-fungi-grow/ Thank you for your time. Regards, ORF

Hello In evolution, the archetype rule is the "natural selection" rule. Are the other selection rules? (technological selection rules, cultural rules, etc) Thank you for your time. Regards, ORF

Hello What are the "debugging symbols" ? I have a naive idea about what the debugging symbols are, but based only in my short experience: for me, they are a kind of flags that can be read during the execution of the program, so you can track the execution. I have also discovered that if you...

Hello How mosquito CO2 detection system works? I found that the detection is made by npa neurons, but nothing is said about how the detection occurs (so, CO2 enters the neuron, and what happen next?) https://www.nih.gov/news-events/nih-research-matters/how-mosquitoes-detect-people Thank you...

Hello Why polyphenols make caffeine (from tea) work slower than caffeine from coffee? Thank you for your time. Regards, ORF

Hello I would like to know more about the history of the discovery of the isotopes, what there was before, and the short term impact on the chemistry and nuclear physics. Is this topic discussed in any book/review? Thank you for your time. Regards, ORF

Hello. Can a microorganism change behavior of an animal? ( including humans). Thank you for your time. Regards, ORF

Hello As far as I know, the reaction velocity depends on the isotope ("kinetic isotope effect"). So, is the isotope ratio (for example, for Nitrogen or Carbon isotopes) dependent on the trophic level? Thank you for your time. Regards, Alvaro.

Hello I would like to copy a huge amount of data (10-20TB) to 5-10 hdd (internal/external). I thought about using the usual "cp/rsync" utilities, but it will take a long time. After a quick search, I found this unix utility...

Hello Why the uranium glass glows green if it's under UV light? The most accurate thing I have found it's a brief history of uranium glass: somewhere it's said the more uranium oxide you put in the glass, the more intense will be the green light when exposed to UV light. Thank you for your...