61
Technology / Re: Pressurizing using gravity
« on: 11/04/2020 03:50:06 »
what does psi stand for?
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62
Chemistry / Re: Can atomic orbitals be paired?
« on: 03/04/2020 02:06:31 »Is there a basis for pairing atomic orbitals?no. Im pretty sure you have asked this question (in one form or another) several times, the answer is still "no"
63
Plant Sciences, Zoology & Evolution / Re: Did COVID's cousin kill the dinosaurs?
« on: 02/04/2020 23:01:31 »A sudden shift of temperature, sunshine, or whatever, might eliminate several land-based species, but unless all the oceans froze (for which we have no evidence) the seagoing dinos (of which there were plenty) would simply have migrated to somewhere warmer or colder that suited them.
The funny thing about climate is that it applies to the *whole planet.*
Obviously many creatures did survive (on land and in the water). As I understand it, the survivors are not related by biochemistry or genetics (as might be expected for pathogen-driven evolution), but by position in their respective food chains (the only apex predator I am aware of that survived this period was sharks, and they can eat pretty much anything), and flexibility in resource/habitat needs (omnivores > carnivores or herbivores).
The extinction at the K-T boundary appears to have included microbes, plants, fungus, vertebrates, and invertebrates. This seems atypical of a virus, to say the least!
64
Physiology & Medicine / Re: Can a dental problem ever cause chest pain/ headaches?
« on: 02/04/2020 21:57:21 »
Artificial valves might increase the risk of problems, but natural ones are not infallible either. If you have a heart murmur (even an innocent one) then there is an increased risk that bacteria to latch on to surfaces inside the heart.
Bacteria from your mouth can enter your bloodstream if your gums have open sores on them. https://www.webmd.com/oral-health/endocarditis-prevention#1
Bacteria from your mouth can enter your bloodstream if your gums have open sores on them. https://www.webmd.com/oral-health/endocarditis-prevention#1
65
Physiology & Medicine / Re: What are some biologically inert volatile substances?
« on: 02/04/2020 16:21:41 »
neutrinos
66
Cells, Microbes & Viruses / Re: Are 85 Covid-19 deaths ON AVERAGE a day per 60 milllion a reason to PANIC?
« on: 02/04/2020 04:00:05 »
with respect to the original question:
https://public.flourish.studio/visualisation/1727839/
https://public.flourish.studio/visualisation/1727839/
67
COVID-19 / Re: How badly do hospitals dealing with COVID19 need O2?
« on: 24/03/2020 14:59:29 »
After doing much research (and a little experimentation) it seems that oxygen concentration from the air is MUCH more energy efficient and less capital intensive. With adequate filtration and humidification, pressure-swing systems seem like the way to go. For example, a system like this: https://www.oxidationtech.com/og50.html can supply enough oxygen for ten people, and goes for about $6k. There are also. plenty of systems that can supply enough oxygen for hundreds (or thousands), but the prices are not listed, and I don't know how quickly they can be set up.
That said, it seems that non-invasive ventilators are not particularly good at improving outcomes (and if I read this correctly, most who get the invasive ventilators die anyway)
https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30110-7/fulltext
However, it also appears that a major concern of this lancet paper is that caregivers are at increased risk due to aerosol generation.
(At the risk of acting like a hammer and viewing all problems as nails), I wonder about the utility of an electrolyzer to generate oxygen for people, and hydrogen for use in an in-line incinerator to sterilize the exhaust, like so:
schematic4.png (286.75 kB . 3308x1304 - viewed 1655 times)
That said, it seems that non-invasive ventilators are not particularly good at improving outcomes (and if I read this correctly, most who get the invasive ventilators die anyway)
https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30110-7/fulltext
However, it also appears that a major concern of this lancet paper is that caregivers are at increased risk due to aerosol generation.
(At the risk of acting like a hammer and viewing all problems as nails), I wonder about the utility of an electrolyzer to generate oxygen for people, and hydrogen for use in an in-line incinerator to sterilize the exhaust, like so:
schematic4.png (286.75 kB . 3308x1304 - viewed 1655 times)
68
COVID-19 / Re: Is the vapour exhaled by people vaping contagious?
« on: 24/03/2020 14:35:00 »
The vapor by itself is NOT contagious--it's an aerosol of the active drugs (nicotine or cannabinoids, or...?) poteentially combined with perfumes/flavors and carrier (for nicotine products, my understanding is that propylene glycol and glycerol are common). This mix may well be a public health hazard (similar to second-hand smoke), but cannot be contagious, because it does not contain bacteria or viruses or funguses, etc.
However, if a person is sick with an airborne disease, I would not be terribly surprised if exhaled vapors would also carry contagions. How contagious this exhalate would be compared to a normal exhaled breath, I'm not sure.
It's possible that it could be more contagious, if the vapor increases the amount of contagion that is released, or if the droplets protect the virus particles (or bacteria, or whatever), or if the droplets increase the local concentration of virus particles by slowing down the dispersion.
It's also possible that it could be less contagious, if the substances in the vapor (or the high temperatures) destroy, damage, or deactivate the contagion.
At the very least, it could be easier to avoid than a normal breath because it's visible.
However, if a person is sick with an airborne disease, I would not be terribly surprised if exhaled vapors would also carry contagions. How contagious this exhalate would be compared to a normal exhaled breath, I'm not sure.
It's possible that it could be more contagious, if the vapor increases the amount of contagion that is released, or if the droplets protect the virus particles (or bacteria, or whatever), or if the droplets increase the local concentration of virus particles by slowing down the dispersion.
It's also possible that it could be less contagious, if the substances in the vapor (or the high temperatures) destroy, damage, or deactivate the contagion.
At the very least, it could be easier to avoid than a normal breath because it's visible.
69
Chemistry / Re: Since Mercury has some properties of an intert gas, how can it be a metal?
« on: 24/03/2020 13:42:39 »
It is true that mercury holds its electrons a little closer in than other transition metals, and that is reflected by its relatively low boiling point (high vapor pressure) compared to other transition metals (about 360 °C for Hg, vs 770 °C for Cd, which is just above Hg on the periodic table). But this is a far cry from those of noble gasses (roughly –100 °C for Xe).
And as pointed out by Kryptid, mercury also conducts electricity like metals do (increasing conductivity with decreasing temperature).
So clearly mercury is NOT a noble gas, and at STP it is a metal. Why is this? The electrons in mercury actually ARE able to interact with neighboring atoms to form a sea of electrons, despite the claims of the OP. I also wouldn't be surprised if there were also some contributions from the empty 6p orbitals.
https://iopscience.iop.org/article/10.1088/0953-8984/11/24/303/meta
This article itself is behind a paywall, but the abstract says:
And as pointed out by Kryptid, mercury also conducts electricity like metals do (increasing conductivity with decreasing temperature).
So clearly mercury is NOT a noble gas, and at STP it is a metal. Why is this? The electrons in mercury actually ARE able to interact with neighboring atoms to form a sea of electrons, despite the claims of the OP. I also wouldn't be surprised if there were also some contributions from the empty 6p orbitals.
https://iopscience.iop.org/article/10.1088/0953-8984/11/24/303/meta
This article itself is behind a paywall, but the abstract says:
Quote
The reason for the lowering of the DOS at the Fermi level below the free electron value is the hybridization of the narrow d band with the much broader sp band. This opens the so-called Fano gap in the sp density of states, pushing states from the middle of the sp band to the edges. However, the overall (sp+d) density of states has no deep or pronounced local minimum at the Fermi energy.
70
Physics, Astronomy & Cosmology / Re: Neutrinos travelling faster than light?
« on: 24/03/2020 03:02:55 »Hi Halc. That explains that then! It's a typical knee jerk reaction from a newbie like myself when he thinks, hey something DOES travel faster than light! I guess that if the article was aimed at a non scientist like myself then it would have said the neutrinos get to Earth earlier than the light 'because ...'.You too can travel faster than the speed of light, quite easily actually.
https://abcnews.go.com/Technology/story?id=99111&page=1
I would expect that, unless otherwise specified, "the speed of light" is typically meant to mean "the speed of light in a vacuum" ie the constant, c.
Yes, light can get slowed down by interactions with matter. It doesn't even have to be particularly special matter for significant differences (even liquid water can slow light down to about 75% of c)
71
Cells, Microbes & Viruses / Re: Are 85 Covid-19 deaths ON AVERAGE a day per 60 milllion a reason to PANIC?
« on: 22/03/2020 16:05:45 »Quote
A storm descends on a small town, and the downpour soon turns into a flood. As the waters rise, the local preacher kneels in prayer on the church porch, surrounded by water. By and by, one of the townsfolk comes up the street in a canoe.
"Better get in, Preacher. The waters are rising fast."
"No," says the preacher. "I have faith in the Lord. He will save me."
Still the waters rise. Now the preacher is up on the balcony, wringing his hands in supplication, when another guy zips up in a motorboat.
"Come on, Preacher. We need to get you out of here. The levee's gonna break any minute."
Once again, the preacher is unmoved. "I shall remain. The Lord will see me through."
After a while the levee breaks, and the flood rushes over the church until only the steeple remains above water. The preacher is up there, clinging to the cross, when a helicopter descends out of the clouds, and a state trooper calls down to him through a megaphone.
"Grab the ladder, Preacher. This is your last chance."
Once again, the preacher insists the Lord will deliver him.
And, predictably, he drowns.
A pious man, the preacher goes to heaven. After a while he gets an interview with God, and he asks the Almighty, "Lord, I had unwavering faith in you. Why didn't you deliver me from that flood?"
God shakes his head. "What did you want from me? I sent you two boats and a helicopter."
73
Chemistry / Re: Can electricity be generated from two hydrogen electrodes?
« on: 18/03/2020 19:24:52 »
Last answer, then I give up:
You *don't* need a pH gradient to do this--what you need is one substance that is easy to remove electrons from (a fuel) and one substance that is easy to give electrons to (an oxidizer). (honestly, it's probably better to keep both sides the same pH and let H+ be your mobile charge carriers in solution.)
There are neutral pH electrolytes, but then you still need a high concentration of highly mobile ions for it to actually be an electrolyte. High or low pH systems are just easy to make, and often work very well.
If you *insist* on using only pH gradient alone as your sole source of energy, you don't need to (can't have) have an oxidizer/fuel pairing that would release energy when electrons are transferred between them... BUT you *will* still need an oxidizer and a fuel to get electrons to move at all. The easiest way to set this up is to use the exact same reaction at both electrodes, but run one in reverse. That way there is no inherent energy output from running the reactions--only from the pH gradient.
If this doesn't result in an epiphany, I'm out.
OK, is it possible to oxidise oxygen at the alkaline solution and reduce protons in the acidic solution?It is easy to reduce protons. It is very difficult (thermodynamically uphill, requiring energy input) to oxidize oxygen. Even if you meant oxidize water (or even hydroxide) to oxygen, that would require energy input.
You *don't* need a pH gradient to do this--what you need is one substance that is easy to remove electrons from (a fuel) and one substance that is easy to give electrons to (an oxidizer). (honestly, it's probably better to keep both sides the same pH and let H+ be your mobile charge carriers in solution.)
There are neutral pH electrolytes, but then you still need a high concentration of highly mobile ions for it to actually be an electrolyte. High or low pH systems are just easy to make, and often work very well.
If you *insist* on using only pH gradient alone as your sole source of energy, you don't need to (can't have) have an oxidizer/fuel pairing that would release energy when electrons are transferred between them... BUT you *will* still need an oxidizer and a fuel to get electrons to move at all. The easiest way to set this up is to use the exact same reaction at both electrodes, but run one in reverse. That way there is no inherent energy output from running the reactions--only from the pH gradient.
If this doesn't result in an epiphany, I'm out.
74
Chemistry / Re: Can electricity be generated from two hydrogen electrodes?
« on: 18/03/2020 18:55:28 »So on both the acidic and alkaline side, there will be protons and electrons consumed but at different rate, right?one of the rates must be negative compared to the other (ie one side consumes protons and electrons, and the other produces them)
75
Chemistry / Re: Can electricity be generated from two hydrogen electrodes?
« on: 18/03/2020 18:18:49 »
You still need something to reduce and something to oxidize if you want Faradaic current. (NOTE that you can run the hydrogen reaction without using up any hydrogen, it just needs to be there--it will be produced by one electrode at precisely the same rate at which it is consumed by the other)
You can also just mix thee solutions and harvest the heat of neutralization.
You can also just mix thee solutions and harvest the heat of neutralization.
76
Chemistry / Re: Can electricity be generated from two hydrogen electrodes?
« on: 18/03/2020 16:41:23 »
You can supply the same pressure of H2 to both sides and still get a current if the pH is different (though the pH will be equalized pretty quickly.)
Or you could have the same pH, and different pressures of H2.
Or you can supply O2 to both sides, and do ORR instead of a hydrogen electrode...
Or you could have the same pH, and different pressures of H2.
Or you can supply O2 to both sides, and do ORR instead of a hydrogen electrode...
77
Chemistry / Re: Can electricity be generated from two hydrogen electrodes?
« on: 18/03/2020 16:30:06 »
*sigh* I assumed you knew what a hydrogen electrode was, since you brought it up...
78
COVID-19 / Re: Could the Covid 19 virus be used as a type of germ warfare?
« on: 18/03/2020 15:04:34 »
Given the unusual relationship between age and severity, one could be forgiven for wondering whether it had been designed by a millenial or genZ for generational warfare.
But paranoid thinking will not help the situation.
A recent analysis of its genome highly suggests natural evolutionary origins...
https://www.nature.com/articles/s41591-020-0820-9.pdf
But paranoid thinking will not help the situation.
A recent analysis of its genome highly suggests natural evolutionary origins...
https://www.nature.com/articles/s41591-020-0820-9.pdf
79
Chemistry / Re: Can electricity be generated from two hydrogen electrodes?
« on: 18/03/2020 14:59:44 »
You'll need to supply H2 to one side.
80
Chemistry / Re: Can electricity be generated from two hydrogen electrodes?
« on: 18/03/2020 14:48:55 »
answered here: https://www.thenakedscientists.com/forum/index.php?topic=78555.20
I recommend reply # 7
I recommend reply # 7