Moreno
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Why IP telephony haven't become a landline communication standard yet? Some people say this is because Internet is less reliable than phone. But why is it less reliable if exactly the same hardware is used for signal transmission? If hardware is different, where exactly the difference is?
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This article mentions something about employing quantum tunneling for long distance communication. I guess there might be some pdf version somewhere. http://ieeexplore.ieee.org/document/7945581/
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For massive particles typically yes, but radio waves do not consist of massive particles. Therefore I want to know what is the distance through which can they tunnel.
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Is it possible make it somehow that two remote moderate size antennas send information to each other by means of quantum tunneling only, without scattering and absorption anywhere?
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Can electromagnetic waves experience tunneling effect? It is claimed that photons (light) - can. What about radio waves? If yes, what would be exactly the physical details of the process, such as maximal distance this effect can take place, from which point to which point they will tunnel, what is needed to create this effect, etc.
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Still, I want to discuss all advantages and disadvantages of DC current transfer more in detail. What are all the weak points of this technology?
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What are the main reasons centralized electric networks use alternative currents aside the fact AC/AC transformers are cheap and is it guarantied we will never switch to DC in distributed electric systems? Can we design a bipolar DC outlet? What about DC/DC converter prospects?
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There is a large difference between "practical" and "theoretical" answer to your question. I suspect that theoretically it may stay inside for indefinite period of time if we would be able to master box creation on quantum level. There exist such things as a "total internal reflection" and similar quantum phenomenon. The problem is we cannot rule the matter on the atomic scale for now. Even better if your ray of light would stay inside of box as a standing wave.
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1) Heat exchangers indicate hot exhaust and therefore poor plasma conductivity at relatively moderate temperatures. Those are older designs, definitely some ways around it have to be found. Some ways to obtain "cold plasma". 2) I afraid you will need to wait for a long time. For now no researchers do even envision electrically rechargeable batteries which could closely compete with fossil fuels in energy density. Therefore range extenders will be topical in the nearest 50 years at least.
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MHD gen. doesn't need a lubrication system in comparison to free piston and hence no oil filter or oil changes, no friction looses. It may not need cooling system as well, if made of tungsten or ceramics. Hence no radiator, no cooling energy looses. No moving parts. No noise or vibration. I'm not sure what efficiency fuel cells can reach, if they use methanol, gasoline or other hydrocarbon fuel. Perhaps not higher than 20%? And definitely they are bulkier, more fragile and expensive.
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1) Probably it wasn't a correct link. 2) Probably we would need to ionize exhaust components somehow. For example, use electric discharges, lasers, electron beam or rf waves of certain frequencies to get relatively "cold" plasma at 2000-2500 C. If we would succeed to ionize 1/1000 of exhaust atoms it would be regarded as a relatively well conducting plasma. The key is to make it well conducting at nearly any temperature and we would need some external impact for this.
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Free piston engines aren't bad, but coming late. I guess there have to be plenty of problems too. What do you mean under: "converting fossil fuel to laser energy"? Where did you take it from? I'm not sure MHD generator has to be based on Bryton cycle and requires regenerators. Better it would be a one stage cycle with relatively "cool" exhaust.
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In my understanding power to weight ratio of MHD generator is much better than ICE/fuel cells. What is about cost? Is it too high? This one work assumes MHD generators can reach 60-65% efficiencies ultimately. Carnot efficiency at 1.500 C suppose to be around 80% and 90% at 3000 C hot sink and 300 C exhaust temperature. http://veprints.unica.it/616/1/PhD_Roberto_Pintus.pdf
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What do you think about perspectives of MHD generators to replace ICE in series hybrids as a range extender? May it ultimately happen?
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Can long term bright light exposure cause irreversible or long term eyesight damage? A bright light from LED lights, for example? Let say UV component isn't significant and brightness is insufficient to cause bleeding or real burn. What exactly health issues can happen and what medication can help?
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Maxwell's demon and the second law of thermodynamics
Moreno replied to Moreno's topic in Classical Physics
There is also an interesting questions rase regarding our universe heat death. Some people claim that irreversible increase in entropy doesn't apply to our universe because it is infinite and therefore can't be regarded as a thermodynamically closed system. This statement however looks a bit speculative to me because it doesn't explain how entropy reversal is happening in our universe and order increases due to the fact (assumed) it is infinite. Even if it is infinite it doesn't mean we cannot apply such notion as an "average energy density per space" and deny that energy density is prone to equalization practically everywhere in observed universe (which is something like 13 billions of light years). So, the concept of infinite universe doesn't explain why we aren't in the state of the heat death already if we assume that the first or the second law of thermodynamics are never violated. -
Maxwell's demon and the second law of thermodynamics
Moreno replied to Moreno's topic in Classical Physics
Well, my question was kind of: "The thermal fluctuations which surround as (Brownian motion) are extremely small in comparison to our own size and therefore can be hardly useful. But what about extremely tiny conscious creatures from a parallel universe? Would they be able to get any useful energy from these fluctuation which are very small by our dimensions, but significant by their scale? Can extremely small amounts of useful energy (by our scale) be obtained from Brownian motion or not at all?". Another example: "Humans create a tunnel in a parallel universe in which atoms and molecules are huge by our size. Each molecule may be the size of human. The energy of thermal photons these giant molecules absorb and radiate is also huge. Would humans be able to harness any useful energy from Brownian motion in this parallel universe?". -
Maxwell's demon and the second law of thermodynamics
Moreno replied to Moreno's topic in Classical Physics
Sorry, can you develop your questions? Why would they? -
Maxwell's demon and the second law of thermodynamics
Moreno replied to Moreno's topic in Classical Physics
Let to do a curious thought experiment. Modern physics do not set a theoretical limit on how small elementary particles can be with exception of Planck length (1.6 x 10-35 m). What if there can be a small elementary particles (as small to protons as protons to tennis balls) and these extremely small elementary particles are capable to form matter indistinguishable in physical and chemical properties from the common matter known to us. And there exist a tiny conscious creatures made of these tiny elementary particles and each such creature is the size of a common molecule. If these tiny creatures would got in our World somehow, would they be able to gain use of thermal fluctuation in our world associated with Brownian motion an harness energy of fluctuations for some useful purposes (in one word to construct a perpetuum mobile of 2 kind)? -
Here some authors describe "an infinite wavelength resonant antenna". http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.132.4668&rep=rep1&type=pdf If we have a radio wave with infinite wavelength, as they said, what would be the propagation properties of such radio wave? And how much data can it encode/carry?
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Why?
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Usually, it is claimed that An Anisothermal plasma has very hot electrons and much "cooler" ions. https://en.wikipedia.org/wiki/Anisothermal_plasma https://www.comsol.com/blogs/thermodynamic-equilibrium-of-plasmas/ However, I'm not sure if 2000-3000 C dissociated water has many free electrons. We need to have much higher temperatures (more than 10.000 C) to ionize water. But dissociated water consists of H+ and OH- ions, mostly. Is there too large difference between H+ and OH- ion temperatures to talk about non-equilibrium plasma?
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Why exactly? I'm interested in MHD generators. How we define equilibrium or non-equilibrium plasma?
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Is plasma heated to 2000-3000 C and composed of H+ and OH- ions equilibrium or non equilibrium plasma?
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Some sources claim that sucrose is more dangerous than fructose or glucose: https://en.wikipedia.org/wiki/Tooth_decay#Dietary_sugars https://en.wikipedia.org/wiki/Sucrose#Tooth_decay Also, in order to get tooth decay caused by eating fruits you need to consume a really excessive amount of fruits. https://www.ccsmiles.com/does-eating-fruit-damage-your-teeth/ Do you know someone who consumes 17 servings of fruit every day?!