studiot

Hello, Roman, and welcome. I don't know if this is homework or not ? - but it really belongs in Earth Science anyway. We don't do people's homwork here, just help them find the answer for themselves. So a suggestion, I wasn't aware that there was any civilisation in what is now the Ukraine before the Babylonians, but I think the answer you are looking for can be found by looking up Hammurabi and how his laws were written. See what you make of this hint and tell us about the homework or source of the question please.

Yes I agree that a rising plume expands horizontally. But the ascent is much more rapid than the widthwise expansion. I agree that diffusion, without an additional forcing function tends to flatten the gradient. We have all agree these matters many times now. But consider a thermally conductive bar, which is being cooled at one end (the cold end) and heated with the extracted heat at the other end (the hot end) via a heat pump. Which way does the heat flow through the bar ? Here is a reference for the benefit of exchemist. I keep saying this but can't seem to get anybody to pick it up. Diffusion is acting, but it is not only the not the only active process it is not the principal process in the cases under consideration.

Of course there isn't. But the operative word is 'some'. This is a very very small fraction and is not accounted for by the dispersion equation. It is also the reason that concentration boundaries are blurred and gradual, even with only the entropic dispersion acting. It is accounted for by the kinetic theory. Clearly some of the hydrogen molecules in their upwards path will collide with molecules many times their mass and bounce back downwards. But in their downwards travel they will encounter a (very slightly) higher density of heavier molecules so will be even more likely to strike one and bounce back upwards again. It should be noted that this mechanism is not always availble in the dispersion equation. When the dispersion equation appears at 'the 'heat equation' the heat always flows in the direction from higher temperature to lower temperature. Thermodynamics laws forbid the sort of dynamic equilibrium that is established for momentum transport. But I'm sure you are well aware of all this. BTW plume was a very good term to use. Finally my commiserations to Ken for his team's loss in the World Cup. The Aussie soccer team doesn't seem to be of the calibre of their rugger teams.

Have you considered that is because they are not mixed ?

"'Weather' tends to keep the troposphere very well mixed as you suggest." Great statement. +1 Diffusion is a very slow and weak process. Weather is a very fast and strong process. In most cases there are no 'streams' of carbon dioxide or methane (or other unwanted gases), just intermittent trickles. So the words 'accumulation' or 'collection' appear again and again in most treatments. Of course, accumulation is the opposite of diffusion. Here is a simple experiment for your consideration. You have a bucket of hydrogen with a removable lid, suspended 100 feet up in the air. What happens when you remove the lid ? Ken seems to think that the hydrogen diffuses downwards towards the ground, as well as upwards and sideways. So what would be the distribution of this diffused hydrogen above, below and to the sides of this bucket if you measured it ? https://www.hse.gov.uk/pubns/gasdetector.pdf https://www.designingbuildings.co.uk/wiki/Ground_gas https://www.claire.co.uk/home/news/1149-british-standard-8485-code-of-practice-for-the-design-of-protective-measures-for-methane-and-carbon-dioxide-ground-gases-for-new-buildings-amended-and-updated https://www.gov.scot/publications/research-project-investigate-prevalence-co2-disused-mineral-mines-implications-residential-buildings/pages/15/ There you go from New York to Scotland to British Standards to................ Ther is just loads of supporting data all to be be had for the googling and reading.

Why go neither the HSE, the Soc of Environmental Health officers or the Association of Building ontrol Officers, nor I believe your bland statements, always qualified by non realistic additons. How would the gas be released as a stream ? It is randomly generated in small quantities underground and slowly percolates upwards through the ground. (methane and hydrogen will even get though a 300 deep concrete slab) there is moves quite rapidly upwards through the building air until it concentrates under the roof. No streams of gas are generally involved or the site cleanup has not been properly carried out. Concentrates is the reverse action from what you are describing. The gas remains getting more and more concentrated, until it either the supply stops or the gas ignites or it is let out. There is a giant ASDA in one town in Somerset that was built on an old rubbish tip and the disposal method was contolled occasional flare burning. Other methods have been used since on further retail development on the same tip. Eventually doors or ventilators will open causing natural air currents or there may be forced ventilation. Either way if the supply stops the gas will eventually dissipate by these processes, just as you say. But that could take a very very long time. The trenches were subject to considerable disturbing agents called winds. It was well known that the gas would 'hang around' much longer on windless days. Ken's thesis, and you appear to support it, is as far as I can tell, that there diffusion reduces the concentration gradient to zero. It is a requirement of the diffusion equation that no diffusion occurs unless there is a forcing function. The pre existence of a concentration gradient constitutes such a forcing function, but slowly subsides to nothing as the concentration gradient is reduced. So Ken is right in that if the cap is suddenly taken off a concentration gradient and nothing else is acting then the concentration will even out to nothing and then diffusion will cease. But that is not the case here as there are always other forces acting continuously and intermittently.

Don't apologise, +1, it was meant as a helpful comment/piece of information. We all have to learn these things somewhere along the line. A good example of dilatation is what happens when you walk on wet sand on the beach.

Tank you for that useful addition. +1 It is also what made these chemical agents so dangerous. Mustard gas has a molecular weight of 159 and phosphine 34. Compare with carbon dioxide at 44. That is my definition of an inhibitor, not a poison. But nevermind it will kill you all the same. Well I thought I had provided a pretty comprehensive answer, with several different parts to it. 1) A discussion as to the meaning of the words you guys used, notably stratification and a stement to the effect that there will never be a series of layers, each composed of one gas only, lying one above the other, 2) A discussion about what actually does occur, notably that a concentration gradient develops for all gasses, but the spatial distribution of that gradient varies with the molecular weight of the gas. 3) A discussion of the diffusion equation and the requirements for applying it in a gravitational field. 4) A mathematical outline of the kinetic theory mechanism for this. In what way was that insufficient ? You have still to answer the question why do lighter gases such as hydrogen and methane go straight up when released and collect in and under roofspaces ? Since you now have the maths, why do you need some nerd reference ? Why can you not check it for yourself ? Why do the building regulations require roof venting for this collecting gas and why does it continue straight up towards the stratosphere when it exits the vents ?

Do the maths. The diffusion equation describes the response of the particles to a forcing function. In this case gravity. It also requires the particles to be (1) non interacting and in the versions referred to to be (2) identical, and (3) have no significant disturbing function. What happens when a particle bumps into another, under condition 1 above, that is a) 22 times a heavy (hydrogen into carbon dioxide) ? b) 1.5 times as heavy ? (nitrogen into carbon dioxide) ? Well momentum and energy is preserved so if m is the mass of the lighter molecule and M the mass of the heavier; u and U the before and after velocities of the heavy molecule; and v=0 and V the before and after velocities of the light molecule then [math]Mu = MU + mV \Rightarrow M\left( {u - U} \right) = mV....................1[/math] momentum balance [math]Mu{}^2 = M{U^2} + m{V^2} \Rightarrow M\left( {{u^2} - {U^2}} \right) = m{V^2}..........2[/math] Energy balance Divide equation 2 by 1 V = (u + U) So the lighter molecule is greatly accelerated and the heavier one slightly decelerated. That is the kinetic processes of diffusion tend to speed up the lighter moelcules and slow down the heavier ones. Remember also that in the atmousphere there are very significant disturbing functions. So significant that our very climate depends upon really massive amounts of energy being transported from the tropics to the polar regions, after first being high into the air by rotational forces due to the Earths rotation. This energy effect was not realised until the mid 20th century.

Further explanation. Dilation is a general term in English meaning to get larger and applies to many different properties such as the size of an opening, the duration of a time period in relativity, and so on. Dilatiation is a specific scientific term for an increase ( or decrease if negative) in volume due to stress (mechanics) or other factors such as pore pressure (earth science).

Aha, two processes. Thank you, +1 I will read further. Agreed and this is why I said that prior information is also required by the observer. In your example this would mean there must also be some law akin to Pauli acting, stating that although either of us could pull out a coin at random, the other must then be opposite. This would correspond to the events not being statistically truly independent.

Thank you both. So why does do the lighter gases I mentioned not diffuse downwards to form a homogenous gas body inside a large commercial building (tin sheds I call them) ? I see that you have both avoided this question. The points I am making are 1) That the Earth's atmousphere is never perfectly still. 2) That 'stratification' fully developed into layering is not happening. However there exists a measurable concentration gradient for any gas in the atmousphere, depending upon the difference of its molecular weight and the average for air. In fact as we rise in the atmousphere there exists a concentration gradient for air itself (or its average). 3) A point I didn't make before, If we look high enough the concentration of very light gases like hydrogen will be changed by processes which change or even break up the molecules. 2)

Well I disagree. Let us look at it another way. If the gas was hydrogen or helium or methane what would happen ? The truth is that mixing will occur if there is sufficient activity in the gas body and then gases will keep remixing so appear to to remain unstratified. As you correctly point out, there is a lot of activity in the atmousphere. In perfectly still air there is no mixing. Equally in a tub of denser gas. with no disturbing flow activity the denser gas will remain in the tub. This is just the inverse of the lighter gases I mentioned collecting under roofspaces. I have measured this latter effect and designed buildings in danger of this to be safe. In Australia you have a large amount of spare space and no need to build on former rubbish tips. In the UK we don't have that luxury, but rubbish tips release methane and some much smaller amount of hydrogen, which are very dangerous gases if allowed to collect in upper spaces.

Thank you for your reply to my post the photos are the most useful informatuiom you have posted so far. Coin cell bateries may be housed in stainless steel, but there are lots of things on you Nintendo that are not and all, including that battery are subject to some forms of corrosion. Given the photograph which also shows failure of two decoupling capacitors, one showing serious leakage and lead corrosion I would question the history of your apparatus, rather than accusing your CR2032.. I can't identify the orange component next to the edge of the board by the battery, but that looks also to have suffered catastophically and may be the source of your issues.

If you do have corrosion or just general contact oxidation to clean off try a glass fibre pen. https://www.amazon.com/s?k=glass+fibre+cleaning+pen&ref=nb_sb_noss

Thank you for that correction, can you elaborate please ? +1

Wow! I think this second quote says it all !

To entangle two particles they have to have some (common) property that can only take two different values, but possess the same energy. In a bonding orbital you have two electrons that have this property since they must have opposite spins, due to the Pauli exclusion principle. Conservations laws, eg momentum may provide a pair of entangled particles in the right circumstances such as pair creation. But you can't just take any old pair of particles that happen to be close and say they are or will become entangled, for example adjacent electrons in the cathode ray stream impinging on your cathode ray tube are not entangled. Does this help ?

Of course there has to be a source of carbon dioxide, why would anyone think otherwise since its normal concentration in free air is so low ? But it doesn't have to be a high pressure or continuous source. Because, as I said, carbon dioxide is heavier than air (has a higher molecular weight) so will tend to accumulate in hollows or ever walled spaces. It will not necessarily mingle with the free air outside the confined space. During my training we were made aware of a recent fatality at a nearby chemical plant in an otherwise open area within the plant having side walls/fences, but no roof. The source was a leak from a CO2 pipe. A worse disaster occurred in the home counties (in the chalk) where they were laying new deep sewers. Over the weekend and for perhaps sometme before there had been a lot of rain. When work recommenced, a man went down the ladder to the bottom of the manhole shaft and collapsed. When his mates looked down and saw this, two more went down to fetch him. They too collapsed. So the last two, instead of calling for professional help, went down to help them. In all 5 workmen suffocated to death in that manhole shaft. It is no matter to be treated lightly. Even the definition of a confined space is a legal definition as are the precautions and training necessary to work safely in one.

More than a few things methinks. 1) Carbon dioxide is not poisonous, that is carbon monoxide. 2) Anyone who has (like myself) confined spaces training or worked for the Health and Safety Executive will be well aware that carbon dioxide is 'heavier' that air and displaces oxygen in confined spaces such as manhole shafts into whichit can settle. There concentrations of 10% or more can cause unconsciousness and death by suffocation (not poisoning) if proper precautions are not made. 10% or 100,000 parts per million represents an enormous increase in the present atmospheric level.

Glad to help and I'm sure you have returned the favour for my bo-bos more times than I have for yours. We all make them.

Very interesting +1 Firstly the question of scale. How long are these paths relative to the size of the particles concerned and thier immediated entangled environment ? Note real world 'detectors' tend to be many many orders of magnitude larger than the particles themselves. Secondly what do the detectors detect ? Just the presence of a particle ? How do you know it is entangled and what it is entangled with ? What about random interfering particles ? and yes all this would become much clearer if you told us what particles you are referring to. For instance If you are talking about photons (or electrons) and spin if you know that it is spin up, how did you fnd this out without interacting with it ? (Entanglement for photons is usually about polarisation) These are samples of what I mean by being more specific.

Presumably you have some references to scientific fact, figures and measurements to back these statements up ?

The answers you get from QM are often already rather vague. As a consequence you need to be a lot more specific with any questions you ask.

Actually no. If we use τ = ict then we get an all positive metric. It is the squares of the space and time coordinate axes that have to be of opposite signs, not their first degrees.