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 Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US 
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I think that's because the refrigeration cycle of a typical refrigerator/freezer is designed so that the evaporator coils (the cold part) gets down below freezing while it's running (usually below zero degrees Fahrenheit, because the freezer section is typically at or around zero).
This removes a lot of water vapor from the air, because as the air temperature drops, the maximum capacity for water vapor drops (the relative humidity, or the ratio of actual water content and maximum potential water content, goes up) until saturation (relative humidity is 100%) is reached at the coil surface. From here, any further drop in temperature requires that water be removed from the air, in order to keep the relative humidity at or below 100% (excess moisture condenses out of the air, freezing onto the coils as frost).
The superchilled air is then circulated through the freezer, where it begins to heat up due to incoming heat from the room surrounding the freezer. Because the air's water content was removed during cooling, and it's maximum capacity for water is rising again with the temperature, the relative humidity of the air begins to drop significantly. The air then circulates to the refrigerator section as needed to keep that section cool but above freezing, ensuring that the refrigerator air has even lower relative humidity than the freezer air.
The water that freezes onto the coils is melted occasionally through a defrost cycle, where the refrigerant cycle is briefly turned off, and a heating element turned on to quickly heat up the evaporator coils. The melted Frost drains into an external pan, under the fridge where it can slowly evaporate into the room.
This modern way of actively drying the air before it ever gets to the inner airspace is what keeps the freezer/fridge mostly frost free, as the extremely dry air can actually cause any frost in freezer/fridge to directly evaporate at freezing, a process called sublimation.
This same process of subcooling the air to remove water vapor is used by all AC units to properly cool hot air without driving the relative humidity of the cooled air to 100%. If in certain applications, the heat removed from the air is added back to it after initial cooling and water removal (end result is same temperature air with less humidity), and you get a dehumidifier.
This area of study is known as psychrometrics, and has real application in perception of comfort or dessication of items in climate controlled spaces. It is a key design aspect of all refrigeration cycles and their applications.
Good question bruh!
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“The Universe is under no obligation to make sense to you” -NDT
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drawde
Registered: 11/15/09
Posts: 5,268
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 Re: General Science Thread  [Re: Data]
#823806 - 02/16/17 05:50 PM (7 years, 9 months ago) |
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Is anyone here good with python?
I'm sorely lacking someone I can just hit up with random questions.
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King Koopa said:
The amount of pot that Gask smokes is equivalent to a guy shooting heroin on weekends
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poor boy
Village Idiot
Registered: 06/07/13
Posts: 16,230
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Re: General Science Thread [Re: drawde]
#823811 - 02/16/17 06:21 PM (7 years, 9 months ago) |
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hell yeah i am. more so with monty though...
--------------------
Learning to love life by living through loss and mistakes
Lessons learned then gradually surfacing, Letting go, stripping naked to scream
I am not perfect nor do I strive to be, I am alive in this world of face first falls and public breakdowns
I'm a retarded, disfigured clown
Dying to be heard through the simple art of letting this heavy wall finally fall
I'm an equal being of no race, or color, a hallucination if you will
Sneaking into the lives of strangers, and letting them fall apart to a new rhythm just to feel better
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Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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Re: General Science Thread [Re: poor boy]
#823814 - 02/16/17 06:36 PM (7 years, 9 months ago) |
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I'm not good with python, I know just enough to piss myself off trying to implement my ideas.
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“The Universe is under no obligation to make sense to you” -NDT
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drawde
Registered: 11/15/09
Posts: 5,268
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Re: General Science Thread [Re: Data]
#823822 - 02/16/17 08:51 PM (7 years, 9 months ago) |
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I'm really amazed how much utility learning it has afforded and I'm just six weeks in.
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King Koopa said:
The amount of pot that Gask smokes is equivalent to a guy shooting heroin on weekends
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 TrueHerbCrystal
Uncertified Oregrowian
Registered: 02/07/09
Posts: 1,352
Loc: Emerald City
Last seen: 6 years, 2 months
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Re: General Science Thread [Re: Data]
#823831 - 02/17/17 05:04 AM (7 years, 9 months ago) |
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quite intriguing science there Data. Refridgators always fasinated me in how they work.
i got another one: Its about sound.
Sound/music studios are lined with material that absorbs sound and insulates so sound doesnt escape or come inside the room. Does sound from speakers wear out this material over time? Or is the force from the speakers too low to do damage?
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poor boy
Village Idiot
Registered: 06/07/13
Posts: 16,230
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monty python... geeze...
--------------------
Learning to love life by living through loss and mistakes
Lessons learned then gradually surfacing, Letting go, stripping naked to scream
I am not perfect nor do I strive to be, I am alive in this world of face first falls and public breakdowns
I'm a retarded, disfigured clown
Dying to be heard through the simple art of letting this heavy wall finally fall
I'm an equal being of no race, or color, a hallucination if you will
Sneaking into the lives of strangers, and letting them fall apart to a new rhythm just to feel better
|
Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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Acoustic Foam is usually made of polyeurethane cells filled with some sort of gas. The structure allows for any force applied to the foam to be as evenly distributed throughout the bulk of the foam as possible. Because of this, and the fact that polyeurethane (and most polymers) can be custom formulated to have certain properties, the chemical makeup of acoustic foam polyeurethane is typically dialed in to be as "gooey" as possible, to provide an efficient means to convert macromotion (sound waves) to molecular motion (heat).
Because of this "gooey" property, and the ability of the foam to evenly distribute force throughout the bulk, it is highly resistant to stress fatigue, and thus will be slow to break down from high amplitude sound waves.
However, in order to behave in this manner, the chemical bonds holding the material together are extremely flexible, long, and weak (low bond energy). While most of the physical energy imparted on the material from sound does not impart enough energy to break or rearrange these bonds, the effects of spontaneous elastomer breakdown does give this polyeurethane material a shelf-life of about 7 years. While this shelf life is affected by the temperature of the foam (and thus slightly affected by the conversion of sound motion into heat), this has such a small effect on the material that it can be considered negligible (a large pipe organ puts out about 10W of sound power, which would be negligible when spread out over the 600 sq.ft. of a 10x10x10 foot room covered in foam).
So the answer is, the normal breakdown of the unstable elastomer material will be so much stronger of a contributor to the life of the acoustic foam than the contribution from the sound waves from a speaker system.
I had to dig for this answer, good question TrueHerbCrystal! If I haven't explained this well enough, feel free to ask more specific questions about the parts that I may have missed.
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“The Universe is under no obligation to make sense to you” -NDT
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TrueHerbCrystal
Uncertified Oregrowian
Registered: 02/07/09
Posts: 1,352
Loc: Emerald City
Last seen: 6 years, 2 months
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Re: General Science Thread [Re: Data]
#824024 - 02/23/17 09:36 AM (7 years, 9 months ago) |
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Amazing! I definitely got thhe basics of how the polyuranthane works. Thanks man  So there is a 7 year lifespan, very nice. 
Got another one for ya: Current TV technology has "organic" properties, such as "OLED" or Organic Light Emitting Diode.
What makes it organic and why is it better than nonorganic LED?
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Thebooedocksaint
Dead Dictator
Registered: 05/11/09
Posts: 5,729
Loc: Wild & Free
Last seen: 1 month, 11 days
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Organic generally, from a chemistry perspective, means carbon, carbon containing molecules, and the chemistry of those molecules.
I'm sure someone with training in materials sci may have a better idea about what an OLED is.
My understanding of LED's in general is pretty weak, but from what I understand about similar phenomena/components it may not be that hard to describe. I would propose what I believe it is, but I'd rather wait to see if Data comes in with a more complete answer/eventually have motivation to look it up.
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"Je pense, donc je suis (I am thinking, therefore I am)." -Rene Descartes
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Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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Boondocks is exactly right. In the case of organic LEDs, the word "organic" simply means that the active emitting region is composed of carbon-based polymer semi-conductors, rather than inorganic silicon-based semiconductors.
OLEDs and LEDs basically work the same way. Two materials (one that is electron rich, and one that is generally missing some electrons) are placed next to each other. Because they are semi-conducting, extra electrons from the first material cannot freely flow to the 2nd material to fill the spaces where electrons should be (called holes for simplification of the model). When no current is applied to the materials, there is only a very thin "depletion layer" where the two materials meet, where electrons and holes can diffuse across the materials and cancel each other out.
The thing about the two materials is that the ground states of their respective electrons are different, meaning that the electron-rich first material contains electrons that have a higher potential energy than an electron that would occupy one of the holes in the electron-deficient second material. This difference in potential energy is known as the energy band gap. The band gap is usually given in electron-volts (eV).
When a current is applied across the junction, it can effectively be thought of as the power supply pumping more electrons into the electron-rich first material, and holes into the electron-deficient second material, until the voltage across the material junction exceeds a critical value necessary for the semi-conductors to allow current to flow through the junction. The higher energy electrons flow into the depletion layer and combine with the holes, thereby instantaneously dropping in potential energy. This results in a quanta of energy equal to the band gap energy being released from the electron-hole merger in the form of a photon, with a frequency equivalent to the energy of the photon (and thus the band gap), as defined by the Planck–Einstein relation:
E = h*f
Where:
- E = energy of the photon (equal to the band gap energy in eV)
- h = planck constant (6.582x10-16 eV*s)
- f = frequency of the photon in Hz
Thus, by controlling the band gap between the two semiconductors through careful dopant concentration and selection, you can precisely dial in the energy (and thus the frequency and color) of all of the photons emitted from the junction when current is flowing. In conventional LEDs, these materials are made up of extremely pure silicon and inorganic (usually metallic) dopants. In OLEDs, the layers are made up of carbon-based (and thus organic) polymers and various dopants to achieve the desired band gap.
Because polymers are manufactured rather than refined, it is much easier to control the purity of the polymers. Additionally, because organic polymers typically have much lower bond energies, they are better able to absorb misalignment during crystal growth without forming large dislocation defects. This allows for large sheets of OLED base layers to be manufactured, doped in precise locations (to give red/green/blue emitting regions on the same sheet), and still be flexible enough to apply to a TFT power supply matrix...thus yielding a lightweight, potentially flexible, and extremely thin display in which every single pixel is actively emitting its own light, and does not need a back light (and thus can produce true black and extremely vivid contrast).
A standard LED display is typically a color LCD (liquid crystal display) with a standard LED array as a backlight. The LEDs cannot be economically utilized as an active display because their silicon-based semiconductors are more brittle, larger, and harder to produce and arrange en masse as a single solid display panel that is capable of 4K resolution and above.
The only disadvantages of OLEDs are the service life (which is much shorter than conventional LEDs due to the sensitivity of the organic polymers involved), and the fact that they are not as efficient as their inorganic counterparts (especially in blue, but blue has always been a problem child for LEDs in general).
Don't let the word "organic" fool you though, this technology still uses the same toxic dopants and awful supply chain practices as conventional LEDs, and the organic polymers are more than likely manufactured using petroleum as the starting component. 
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“The Universe is under no obligation to make sense to you” -NDT
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Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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Re: General Science Thread [Re: Data] 1
#824071 - 02/23/17 09:35 PM (7 years, 9 months ago) |
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I had an interesting idea today at lunch. I'll have to run the math on it, but it may have potential for either a high-power radio amplifier, or a way to get some hyper-efficient solar energy:
The solar winds are a mixture of protons, electrons, alpha particles (helium nuclei), and trace amounts of heavier atomic nuclei, that streams from the sun with an average speed of about 450 miles per second.
Due to the spreading out of the particles as they move away from the suns surface, all of the solar winds that impacts the area of the Earth at the radius of the Earth's orbit comes from a small circular patch of the sun's surface that is about 58km across. The angle between one side of the earth and the opposite side, as seen from the sun, is roughly 2/1000ths of a degree.
If one could apply the small amount of electromagnetic field energy necessary to change the initial path of each electron and each proton coming from this small patch of sun, such that over their long transit from the sun to the Earth, they separate into two beams (on of protons, the other of electrons) that each arrived on opposite sides of the Earth, then one would have access to about 900 MW of electrical energy.
I'm betting that if I do the math, I'll be able to show that we currently have the ability to do this (well, minus the collecting grids, we would have to build those). I'm willing to bet that the electron/proton path corrections can be made with less can 100W of power applied at the suns surface, and that we can achieve that will less than 1MW of transmission power at the earth's surface (which we are perfectly capable of doing right now).
I'm also willing to bet that this technique could be refined to deliver much more than 900MW to the planet...a series of solar orbiters with highly eccentric orbits could provide the planet with a steady stream of electron/proton beams that could utilize much more initial area of the sun (and thus concentrate huge amounts of power for Earth's utilization.
Finally, I think this could be used as a way to take a small communication signal at Earth's surface, amplify it to several GWs worth of transmitting power, and then beam it out towards an intended target. This will take a little more work, but I think I can get electrons and protons to "bunch" together in response to a small changes in velocity due to a radio-frequency signal input. This may take a week or two to work out, but it could be the beginnings of true interstellar communication.
More to come on this.
TL:DR, I might be able to show that we can hijack the sun's solar winds as a way for us to harness a large amount of power for various uses. Its neat, but I still need to do the math.
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“The Universe is under no obligation to make sense to you” -NDT
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poor boy
Village Idiot
Registered: 06/07/13
Posts: 16,230
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Re: General Science Thread [Re: Data]
#824094 - 02/24/17 05:09 PM (7 years, 9 months ago) |
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i know stuff too. i just cant remember right now. stupid drugs...
--------------------
Learning to love life by living through loss and mistakes
Lessons learned then gradually surfacing, Letting go, stripping naked to scream
I am not perfect nor do I strive to be, I am alive in this world of face first falls and public breakdowns
I'm a retarded, disfigured clown
Dying to be heard through the simple art of letting this heavy wall finally fall
I'm an equal being of no race, or color, a hallucination if you will
Sneaking into the lives of strangers, and letting them fall apart to a new rhythm just to feel better
|
drawde
Registered: 11/15/09
Posts: 5,268
|
Re: General Science Thread [Re: Data]
#824154 - 02/26/17 11:03 AM (7 years, 9 months ago) |
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What is the status of Fukushima? There seems to be a 'its not a big deal' narrative now.
I want to investigate myself but don't have much time at the moment, though it's been on my mind a lot.
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King Koopa said:
The amount of pot that Gask smokes is equivalent to a guy shooting heroin on weekends
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figgurate
Stranger
Registered: 02/22/17
Posts: 20
Last seen: 7 years, 8 months
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Re: General Science Thread [Re: drawde]
#824161 - 02/26/17 06:45 PM (7 years, 9 months ago) |
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Literally takes 2 seconds to find out yourself lol.
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drawde
Registered: 11/15/09
Posts: 5,268
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Re: General Science Thread [Re: figgurate]
#824166 - 02/26/17 08:43 PM (7 years, 9 months ago) |
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I'm looking for someone who is well researched into it who can impart their findings unto me.
I'm well aware search engines exist that lead you to articles...
I watched a few youtube videos on the subject today. One discovery channel video that was like 'everything is fine, nothing to see here', and another video of someone debunking a video claiming the event is apocalyptic.
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King Koopa said:
The amount of pot that Gask smokes is equivalent to a guy shooting heroin on weekends
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Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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Re: General Science Thread [Re: drawde]
#824167 - 02/27/17 02:11 AM (7 years, 9 months ago) |
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I try to stay out of current events as much as possible, because as you've pointed out there are "sources" that can claim to debunk other "sources" on just about everything.
Having said that, the story we get in the nuclear industry is that "we got lucky and it wasn't nearly as bad as it could have been, but we still need to upgrade all of our shit so it doesn't happen again, because we might not be lucky next time". I have not done extensive research on the matter with respect to trying to definitively verify or deny this stance, or its biases.
That being said, I will offer some tidbits to think about. In January, Scandinavian countries noted a spike in Iodine-131 (a short lived isotope with a half life of about 8 days I think). The source of the spike is expected to be a pharma accident, since nobody is owning up to it and there was no satellite information to indicate a Nuclear test in the far north.
When the chernobyl unit melted down, the cold war was very much in effect. Despite this, the entire world managed to figure it out when radiation air monitors and body radiation monitors started going apeshit at nearly all nuclear-related facilities all over the world. Even in a time of extreme paranoia and withholding of information, the world could figure out when a major radiological release had occurred.
This has not been the case with fukushima. We have had no spurious alarms in our radiation air monitors, even the ones outside in the open air surrounding the US nuclear facilities.
I've also done a calculation in the past, regarding the spread of the reported release of isotopes into the Pacific. I will try to see if I can find it, but I do remember the risks to the food supoly was minuscule. The vast majority of isotopes decay away very quickly, and most of the rest do not bioaccumulate,and thus are evenly spread out to the point of being nonexistent. What remains will tend to accumulate in bony tissue of apex predators, which are the parts of fish that we don't like to eat too much of, and the majority of which will end up as marine snow in the deep ocean before ending up on our plates.
The immediate safety of humans aside,this was a serious event, and while it does tend to get immensely overblown by the extremely nuclear-paranoid, the lessons learned cannot be ignored. In the US, major projects and emergency plans have been designed and put in place at all reactors, at the request of the NRC, as a direct result of Fukushima. With public opinion so low in the US for nuclear power, we are almost forced to grossly overreact to situations like this in order to satisfy the mostly uneducated, fear-driven responses of the general public. It hurts the budget, but I'm not really one to complain about more strict safety protocols at nuclear plants
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“The Universe is under no obligation to make sense to you” -NDT
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figgurate
Stranger
Registered: 02/22/17
Posts: 20
Last seen: 7 years, 8 months
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Re: General Science Thread [Re: Data]
#824169 - 02/27/17 06:25 AM (7 years, 9 months ago) |
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drawde
Registered: 11/15/09
Posts: 5,268
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Re: General Science Thread [Re: figgurate]
#824171 - 02/27/17 07:31 AM (7 years, 9 months ago) |
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Thanks D, makes me feel better people inside the industry view it that way.
This Iodine thing sounds interesting to look into and speculate about.
Quote:
figgurate said:
https://www.sciencedaily.com/releases/2016/06/160630214454.htm
2 seconds.
Hey asshole, we are open to asking each other questions here and generating conversation. This is a slow moving board in case you haven't noticed.
About 50% of the traffic here could be googled but we elect to be social and have discourse, something you seem to need work on.
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King Koopa said:
The amount of pot that Gask smokes is equivalent to a guy shooting heroin on weekends
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figgurate
Stranger
Registered: 02/22/17
Posts: 20
Last seen: 7 years, 8 months
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Re: General Science Thread [Re: drawde]
#824172 - 02/27/17 07:58 AM (7 years, 9 months ago) |
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Why you callin me an asshole? I helped you and answered your stupid question. You should be thanking me.
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