Recent comments in /f/askscience
skisushi t1_j3uqstf wrote
Reply to comment by doaardvarksswim in During digestion, does ethanol react with lipids to form esters, at a significant conversion rate? by spamarind_soda
Nope. Nearly all death is at equilibrium. Steady state with energy inputs is not equilibrium. Nerves, muscles, etc are constantly utilizing energy to avoid the equilibrium state.
kilotesla t1_j3uolby wrote
Reply to comment by JamesTKierkegaard in Will water ice melt faster if allowed to drain, or remain in the meltwater? by terjeboe
>It's not glass compared to air that's the issue so much as compared to water or ice. The air is the environment in this situation so if the system is in a glass container the heat transfer to the air will be negligible compared to the surface area of the water and ice (which again depends on the shape of the container greatly).
In a series circuit with a very low resistance resistor, a medium value resistor, and a large resistor, fed by a voltage source, the voltage drop across the medium value resistor is affected a lot more by the large resistor than by the smallest resistor. If we have 1 ohm, 33 ohms, and 1000 ohms in series, the drop across the 33 ohm resistor is 3% of the source value, even if we drop the 1 ohm resistor to 0.1 ohms. We can't conclude that the 33 ohm resistor will have a lot of voltage drop because it is huge compared to 0.1 ohms. That doesn't work.
The glass outer surface will be very close to the same temperature as the water. The heat flow per unit area is determined by the temperature difference between the water and ambient. If the outer glass surface were at 1 C instead of zero, the temperature difference with respect to ambient would not change significantly. And the surface temperature wouldn't even be that high.
>Realistically, radiation is going to be a meager source of heat loss, even hot water radiators to heat houses only supply about 5% of their heat contribution through actual radiation, and that's at higher temperatures.
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5% is way too low. Modern "radiators" have fins which enhance convection but not radiation, so convention is typically larger, but radiation is still about 25%, even just counting the outward facing surface.
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In the range of temperatures we are talking about, radiation is reasonably approximated by a linear function of temperature difference. Yes I know, that's counterintuitive with that fourth power, but it's T1^4 - T2^4 , not (T1-T2)^4. On the other hand, natural convection is nonlinear enough that it drops as a fraction of overall heat transfer when the temperature difference gets smaller.
[deleted] t1_j3un0j9 wrote
Reply to comment by [deleted] in Can the human body clear a HPV infection copletely? by Terradubia
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[deleted] t1_j3umb3m wrote
Reply to comment by VT_Squire in Will water ice melt faster if allowed to drain, or remain in the meltwater? by terjeboe
That's like proving that ice will melt faster in 25°C of unlimited water than it will melt in 25°C of unlimited air.
lonelysuffering OP t1_j3ulyd7 wrote
Reply to comment by Archy99 in Can autoimmune illnesses occur without autoantibodies? eg can neutrophils decide to become autoimmune? by lonelysuffering
Right yea autoinflammatorh and autoimmunity. Autoinflammatorh can happen without autoimmunity. The rush of neutrophils to injuries right. Thank you
[deleted] t1_j3ultp9 wrote
Reply to comment by mjbat7 in Can autoimmune illnesses occur without autoantibodies? eg can neutrophils decide to become autoimmune? by lonelysuffering
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[deleted] t1_j3ulqcz wrote
Reply to comment by TerjiD in Will water ice melt faster if allowed to drain, or remain in the meltwater? by terjeboe
In this particular case there is no way for air to get more heat from the surroundings.
[deleted] t1_j3ulian wrote
Reply to comment by wm_berry in What exactly are ashes? by krFrillaKrilla
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[deleted] t1_j3uhan5 wrote
Reply to comment by wm_berry in What exactly are ashes? by krFrillaKrilla
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JamesTKierkegaard t1_j3ueydg wrote
Reply to comment by kilotesla in Will water ice melt faster if allowed to drain, or remain in the meltwater? by terjeboe
It's not glass compared to air that's the issue so much as compared to water or ice. The air is the environment in this situation so if the system is in a glass container the heat transfer to the air will be negligible compared to the surface area of the water and ice (which again depends on the shape of the container greatly). If it's a thin metal container then water remaining will probably win in most configurations simply because it will act as a convective exchange surface. Realistically, radiation is going to be a meager source of heat loss, even hot water radiators to heat houses only supply about 5% of their heat contribution through actual radiation, and that's at higher temperatures.
jeffersonairmattress t1_j3udqxw wrote
Reply to comment by TerjiD in Will water ice melt faster if allowed to drain, or remain in the meltwater? by terjeboe
Yes. Also why ice storage houses has a raised base of spaced straw bales and a drainage system.
[deleted] t1_j3udhgm wrote
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spamarind_soda OP t1_j3ubw8y wrote
Reply to comment by CrateDane in During digestion, does ethanol react with lipids to form esters, at a significant conversion rate? by spamarind_soda
Interesting. Thanks!
finalattack123 t1_j3uahgd wrote
Reply to comment by thred_pirate_roberts in Will water ice melt faster if allowed to drain, or remain in the meltwater? by terjeboe
The ice cube will melt unevenly. It happens all the time when I poor myself whiskey. Though the whiskey isn’t ice cold. You can easily see the lower half melt faster and become misshapen.
Key element - big chunk of ice
[deleted] t1_j3ua9li wrote
tdTomato_Sauce t1_j3u8q8u wrote
Reply to Does the immune system have a limit on memory for vaccines? Can we vaccinate against any and all microorganisms if we wanted to? by AdiSoldier245
One thing to consider in this train of thought is that those antibodies and cells are not being constantly produced or maintained. This is the beauty of “immunological memory”.
These cells die off in massive numbers once you clear a pathogen (or following vaccination), leaving behind a tiny colony of memory cells that lies relatively dormant until you encounter the same pathogen (or vaccinate antigen) again.
When that happens, they multiply enormously and mount a whole new immune response, then repeat. This is basically what allows an enormous & diverse immune library.
Using the computing analogy, it’s like running a program vs storing program files. You can’t run all your programs at once, but you can store a lot of program files.
There is obviously a lot more happening in the grand scheme of immunity but hope this is easier to understand!
[deleted] t1_j3u736b wrote
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root_over_ssh t1_j3u71oi wrote
Draining will be faster.
Let's assuming you have a glass of ice in a room with a constant air temperature.
The air will begin to melt the ice and soon you'll have a glass of ice water. The ice is no longer in contact with the air directly and is now submerged in a water that is only slightly above freezing temperatures. It takes a lot of energy at this point to keep warming, so now thay air has to heat the water first before there is a significant temperature gradient to melt the ice more.
Now, if you have the same amount of ice in a strainer, you have 2 changes going on - when the water is removed, they're now 2 separate systems in this constant air temperature exam, the ice doesn't impact the water and the water doesn't impact the ice. Since the water is being removed from the ice "system", you now have less mass to heat up as well and maintain a higher temperature gradient between the air and temperature of the ice.
While water is a better conductor of heat, heating ice with water that is heated by air is still far less efficient than heating the ice from the air directly.
kilotesla t1_j3tzhd4 wrote
Reply to comment by januarytwentysecond in Will water ice melt faster if allowed to drain, or remain in the meltwater? by terjeboe
Those sound like valid results to me. One thing that I'd want to be a little bit careful of is the initial temperature of the bowl. If you had a bowl that started out at room temperature, and it was thick and heavy, it's thermal mass could contribute to the faster melting.
One other question is whether the ice was in the form of cubes, such that air could flow in between them in the strainer case, or whether it was perhaps frozen in the bowls so it was one solid hunk of ice
kilotesla t1_j3tz1rk wrote
Reply to comment by JamesTKierkegaard in Will water ice melt faster if allowed to drain, or remain in the meltwater? by terjeboe
That's good advice that the specifics matter. Since there will be heat transfer by radiation as well as convection, the emissivity of the surface of the container also matters, and if it's polished metal, the low emissivity would retard melting. Also, if the thermal mass of the container is significant, its starting temperature would matter.
When considered in comparison to air, glass is not a poor conductor of heat. It's conductivity is 33 times higher than that of air, and it's likely pretty thin, such that the heat transfer through the air will be the dominant thermal resistance. Air of course has the advantage that it is moving and so carrying heat by convection, not just conduction but it's still going to be the dominant thermal resistance.
[deleted] t1_j3ty0ni wrote
Reply to comment by Coffeinated in During digestion, does ethanol react with lipids to form esters, at a significant conversion rate? by spamarind_soda
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jawshoeaw t1_j3usbqt wrote
Reply to Does the immune system have a limit on memory for vaccines? Can we vaccinate against any and all microorganisms if we wanted to? by AdiSoldier245
Interestingly there is a limit to the bloods ability to transport proteins and it’s viscosity. Too many cells make the blood too thick and too may proteins make the blood too thick. And having antibodies doesn’t work if you have like one molecule-there’s a minimum amount required to work. That said, I’ve never heard of someone maxing out via vaccines.