1

General Science / Re: Hydrogen gas transportation

« Last post by chiralSPO on Today at 02:46:44 »

Water doesn't get compressed

not really (Water is compressible—not much, but enough. Also, I'm not sure why you would say this, as it means that there is less room for added gas—a more compressible liquid would "make room" for the added gas as the pressure increases...)

you can inject any amount of gas into the water tank, as long as it can hold that pressure.

not really (at some point the pressure is high enough that it will liquify, and then there is less compressibility)

The reason to use water is to make hydrogen less dangerous during transportation

How? I can't think of any benefit from adding water. It just means that higher pressures will be needed to store the same amount of hydrogen (which is more dangerous), and more mass being carried (requiring more energy). If the hydrogen catches fire, the water won't do anything to stop it...

2

General Science / Re: Hydrogen gas transportation

« Last post by vdblnkr34 on Today at 01:34:54 »

I didnt get to the part what to use to build it. The idea to compress hydrogen into water as a preventative matter. And bigger the capacity.

Filling the tank with water leaves less room for hydrogen and makes it heavier.

Not really. Water doesn't get compressed, gas does Basically you can inject any amount of gas into the water tank, as long as it can hold that pressure. The reason to use water is to make hydrogen less dangerous during transportation. Can be used something else.

3

Physics, Astronomy & Cosmology / Re: Is there a limit to how hot things can get?

« Last post by Eternal Student on Today at 01:19:51 »

Hi.

Then you have discovered an insect that does not obey Stefan's Law,...

    I'm not sure about Steafn's law.   I'm familiar with the Stefan-Boltzmann law but I've only seen that proven for Black bodies.  There are some things that are not black bodies.

   Wikipedia uses this notation for the Stefan-Boltzmann law:
              j* = total power radiated (per unit surface area) =   ε.σ.T⁴ .     
with σ = constant;    T = temperature in kelvin     but  noteably  ε = emissivity   with  0 ≤ ε ≤ 1   and the following comment....

In the still more general (and realistic) case, the emissivity depends on the wavelength, ε = ε (λ).

   I'm not sure what wavelength they were talking about,  I guess it's the peak wavelength of the whole spectrum of emissions.  Anyway, if it is that then something approximating Wien's law implies  λ_peak ~ 1/T.   Hence, ε = ε(λ(T) )  =   a function of Temperature in disguise.
    So, all I'm asking is that  ε(T)  ~  1/T⁴    over a small range of T,   then the power radiated does lose all of it's dependence on T for that range of temperatures.

Best Wishes.

4

Chemistry / Re: How well understood is the Chemistry of the trans-uranic elements?

« Last post by Eternal Student on Today at 00:49:49 »

Hi.

Thanks @Bored chemist .  It might have been more realistic to think about ligands that just offer a significant polarisation,  a  δ+  on the ligand etc.

   I agree that the main problem is (or was) finding some external factor that rivals the size of the nuclear energy changes.   As I mentioned a little earlier,  when I was a schoolchild I recall being taught that nuclear reactions are completely unaffected by any physical (or chemical) conditions external to the nucleus.  The decay of a nucleus was the textbook example of being as random a process as you will ever find in nature.
     I don't think that's on a school syllabus any longer.   At least some Nuclear reactions are not as random as we once thought.   On a side note, I wonder if Schrodinger's cat thought experiment needs to be re-written.  They usually have a radioactive substance decaying (or not decaying) as the random process determining if the poison is released.   Are there any more good examples of a process we believe to be genuinely random left in science?

Best Wishes.

5

Physics, Astronomy & Cosmology / Re: Is there a limit to how hot things can get?

« Last post by alancalverd on Yesterday at 22:39:37 »

Not if the total power emitted by the fly doesn't change at all with its temperature.   Suppose it always emits  1 W of radiation regardless of the temperature of the fly.

Then you have discovered an insect that does not obey Stefan's Law, and may therefore be an alternative explanation to the Big Bang. The universe was created by a mathematical housefly!

The forum doesn't need to confuse people with complications.

That's half the fun!

6

Physics, Astronomy & Cosmology / Re: Is there a limit to how hot things can get?

« Last post by alancalverd on Yesterday at 22:37:09 »

Is the thermopile powered, thus allowing you to deduce the electron flow, or is it passive, thus meaning you do not know the temperature of it?

A thermopile is a series of thermocouples. If you know the temperature of one set of junctions then the voltage across the  others depends on their temperature difference - no external power involved. But if you break the circuit and inject some current you can raise the temperature of the assembly by ohmic heating. Come to think of it, I'd probably use an auxiliary heater, even simpler.

7

New Theories / Re: What is the real meaning of the most-distant-quasar/galaxy?

« Last post by Kryptid on Yesterday at 21:41:26 »

So, how that "gravitational singularity, a billionth the size of a nuclear particle" could suddenly be considered as Infinite space without breaking the BBT theory?
We also know that there is no empty space with no energy. Therefore, if the Universe started off with an infinite size then by definition it should have some sort of energy.

That does seem counter-intuitive at first, but a singularity of zero size would have made reference to our observable Universe, not the Universe as a whole. To help you understand, consider looking at it backwards through time. You start off with a universe of infinite size, with roughly the same (low) density everywhere. Our observable Universe is a sphere of limited size within this larger Universe. As you go further back in time, the density of all matter increases and the "bubble" that represents our observable Universe gets smaller. However, the Universe as a whole is still remains infinitely large because no degree of shrinkage can change that. So as you go further and further back in time, our observable Universe continues to shrink until it shrinks to zero (or close to zero) size at the moment of the Big Bang. The total Universe is still infinitely-large at this point, however. It's just that the density everywhere is infinite (or at least very, very high).

8

Chemistry / Re: How well understood is the Chemistry of the trans-uranic elements?

« Last post by Bored chemist on Yesterday at 21:29:28 »

adding a handful of singly (or doubly) positively charged ligands at a radius of 150 picometers

How would you get them to stay (either near to your centre atom or even to each other)?

Essentially, in order to change the rate of a nuclear reaction you have to change the energies involved by an amount comparable with the decay energy.
And the problem is that chemical energies- like ligands are about a million times smaller than typical nuclear energies.

9

Chemistry / Re: How well understood is the Chemistry of the trans-uranic elements?

« Last post by chiralSPO on Yesterday at 20:47:23 »

Thanks @chiralSPO .

you're welcome!

10

Physics, Astronomy & Cosmology / Re: Is there a limit to how hot things can get?

« Last post by chiralSPO on Yesterday at 20:45:41 »

I can't help wondering about the original question.
"Is there a limit to how hot things can get?".
I wonder if the answer is "As hot as they were".

 (about 14 billion years ago)

I believe this is correct.