Enthalpy

Hydrogen seems to be the most "compressible" atom, from the measures of liquid and solid compressibility I made. Its volume (vague notion, yes) also depends hugely on the atom it is bound to: oxygen reduces the size of hydrogen, carbon little so. Under pressure, the volume of hydrogen can shrink well below the liquid or solid known at 1 atm. If the density increases enough, hydrogen becomes a metal, so the bonds extend then to the whole crystal, instead of pairs of atoms. With even more pressure, I suppose we observe directly the degeneracy pressure, because hydrogen has no electron shell deeper than the binding electrons. Other atoms would first resist by these deeper shells.

"Paraffin" includes diverse products, for which you can choose the melting point according to your needs. I find beewax (nearly a paraffin) appealing (if the melting temperature fits) for being natural, nontoxic, and welcome by consumers. I expect little thermal difference between concrete, clay... Just take the material that is easy to proceed, something like porcelain. If the cup must be heated on an oven through its bottom, you can't expect the bottom to insulate - unless you find some trick. That's one reason speaking for a heat storing cup being heatedby the contained coffee rather than on an oven.

Hi thedanimal, welcome here! The least bad I see is a paraffin chosen for its melting point, something like 40°C depending on consumers' preference. While freezing, paraffin releases heat - a good amount compared with its mass. Not toxic, but enclose it to avoid the contact with coffee. Wouldn't you prefer a well insulated cup that keeps the coffee hot? Or a plunger that stores heat. It doesn't need to be the cup itself.

How strong could this radiation be? Any hope to measure it? Because, well, last time I hoped to produce extreme UV with an undulator, the figures were so disappointing... And I computed with a short-period magnetic field. Since gravitation fields tend to be vast, I fear the radiated power is below detection. What could be the best case? Electrons orbiting a small black hole near the horizon? Even if the orbital period is 1ms (no idea) radiation will be imperceptible I fear. Could many electrons self-organize in bunches as in an X ray laser to emit more power?

Hello dear friends! Some "chiral" molecules have a right and a left form. http://en.wikipedia.org/wiki/Chiral_resolution http://iupac.org/publications/pac/69/7/1469/pdf/ Biology demands pure enantiomers, especially for drugs, but identical chemical properties make this difficult. Most racemates mix tightly the enantiomers one-to-one when they crystallize, but a few ones separate spontaneously into right and left crystals. To my understanding, such a purified carboxylic acid can separate chiral amines by making salt crystals of differing properties - and purified amines can separate chiral acids. Or such a substance can serve in a chromatography column to separate a produced racemate. Could chiral solvents be useful? I haven't read about them. I imagine they could dissolve a racemate and, as they evaporate, let one enantiomer crystallize first and the other later. ---------- For substances that separate spontaneously, a historical separation process puts two enantiomorph distant crystal seeds in a solution to better control the separation in two forms. One could make a quick machine that concentrates light on little more than the crystal's size, so the optical rotation effect is very perceivable, and analyze only deflected light, which then comes necessarily through the crystal. Optionally, sort the crystals by size first, say by upwind. Use several rays to avoid the bad crystal axis. Sorting machines have often an air jet to spew away the desired items. An air valve reacts in ~20ms, the rest of the circuit must be optimized. ---------- The very controlled Czochralski's process grows huge, nearly-perfect single crystals of semiconductors. http://en.wikipedia.org/wiki/Czochralski_process It has a liquid bath of the material, under slightly melting conditions, and one single zone under slightly solidifying conditions (colder) where a single crystal is already present (at the beginning, it's a seed cut from a previous crystal), so the solid grows only at that crystal, reproducing its organization, orientation... Semiconductors crystals are grown very slowly to have very few dislocation. Because of the crystal's perfection, and because impurities have time to dissolve again, silicon purity passes from 1ppm in the melt to 0.1ppb in the crystal. I suggest to adapt it to chiral separation. Organic compounds can be dissolved instead of molten; the local under- or over-saturation could result from temperature too. Harvesting both enantiomers keeps the solution racemic. Jaws can hold the growing boule once the diameter is attained. The huge selectivity resulting from controlled growth is advantageous. The choice of the seeds determines the crystalline form, for instance the most stable. Nice at polymorph substances. Maybe some final products that normally mix R and S molecules in their crystals would also grow only-S and only-R crystal forms, under such good conditions? This would save the amide step. Czochraslki could crystallize with high selectively more compounds beyond racemates, for instance the amide obtained from a pure enantiomeric amine with an acid. Marc Schaefer, aka Enthalpy

Thanks for your interest! A drawing, yes... I ought to, among other things... Already noted in the "to do" list, but a long time ago. In 2011, when I published the idea (badly redacted) elsewhere. How strong, as you say: it must be tried. I consider it will resemble very closely black ice, which forms by rain on roads in cold air - the process is the same. I feel it's hard, but this is not a measure. Similar processes happen at an ice rink, where ice uses to be hard. I guess liquid water melts a little bit if the preexisting ice before freezing, and this makes the good interface. One fundamental difference: as usual processes freeze water outside in, gas repelled by the crystallization concentrate at the center point (ice cube) or center plane (ice plate). This is a mechanical weak point, and is unaesthetic in sculptures. In contrast, pouring new water at the free surface permits gas to escape the freezing front.

Hello you all! Common industrial methods to produce (water) ice are: For ice blocks, put water in flat containers, chill from the outside by a liquid circulated between many containers. For ice chunks, chill metal tubes by a liquid circulating inside, pour water outside, break the obtained ice regularly. For ice chips, put water droplets in a cold gas. Droplets won't make thick ice, and the first two methods limit the thickness or take too long, because of water's freezing heat (335kJ/kg or 308MJ/m3) and ice's heat conductivity (1.7W/m/K). If you allow an efficient cold plate to be at -10°C, the slowness of growth is 18,000,000s/m at 1m thickness, and: 1mm takes 9.1s, 1m takes 105 days 1min freezes 0.85mm, 1h freezes 6.6mm, 10h freeze 21mm so flat metal moulds dipping in a circulating liquid at -10°C produce plates 40mm thick in 10 nightly hours. -40°C would only double the thickness and cost more energy. I propose instead to grow ice at the surface of already existing ice, hence by the stored cold, but the pre-existing ice is cooled from its growing face, thus speed isn't limited by heat conduction through the ice. One machine raises the existing ice against a cold plate (not too rigid) for a few seconds, then sinks it less than 1mm under the water level for a few seconds (possibly aided by a wave), so all the new water layer freezes (important to stabilize an even surface). One cycle gains about 0.5mm in 20s, so the thickness gains 90mm per hour. Less thickness per cycle would increase the rate. If the ice can be grown around a mandrel, then existing ice is cooled by gas or a liquid bath or jets on a fraction of a turn, and the proper small amount of additional water is brought (spray, bath, brush, sponge...) during the rest of the turn. Cooling and water can alternate several times a turn. Or build a large head that moves (for instance with small circular oscillations) over the growing ice face. It carries many nozzles blowing cold gas and many water pipettes, for instance in an alternating pattern like a chessboard. In a continuous process variant of the many nozzles and pipettes, the thickening bar passes under gates or a continous roof blowing cold gas and adding a bit of water. These machines are energy-efficient, as they need little more cold than the latent heat of fusion, and at a temperature not much colder than 0°C. The three last ones can be nicely fast. Because water ends freezing at its free surface, the produced ice is compact, clear and bubble-free - nice for sculptures. In circumstances where electricity production constraints daytime peak demand, for instance in Japan after Fukushima's disaster, ice produced at night to cool houses during the day is a possible contribution to even electricity consumption. Marc Schaefer, aka Enthalpy

Hello everybody! You know hydrogen is thought as a way of storing energy, before transformation in a fuel cell for instance. Storing liquid hydrogen isn't very easy because it needs really cold temperatures, and pressurizing gaseous hydrogen needs heavy tanks with little capacity, so research is being done to adsorb hydrogen in a solid in the hope to store much hydrogen in a small volume under reasonable conditions. My own two-cents suggestion is to use abnormally light metallic alloys for this purpose. That is, alloys whose volume is bigger than the sum of the volumes of their constituents. My hope is, of course, that more free room is available to hydrogen in the alloy then. Alloys known for their abnormally low density (and modulus) include: - Bell bronze (20% Sn, 80% Cu) - Invar (36% Ni, 64% Fe) Also Mn-Cu (vibration damping alloy) has abnormally low modulus, but I haven't found its density. ---------- Both Ni-Fe and bell bronze alloy elements with slightly different molar volumes. Is this a key to abnormally low alloy density? On the other hand, Ni-Ti has in some metallurgical states a very low Young's modulus but still an abnormally high density, so Young's modulus isn't a reliable indicator. ---------- Shape memory alloys (like Ni-Ti) change their volume over temperature. Provided they store an interesting amount of hydrogen, the density change could be a means to release the gas at will. ---------- Well, I guess competitors like zeolite are already better than any metallic alloy, but anyway, that was my message in a bottle. Marc Schaefer, aka Enthalpy

In a commercial document, I'd put a picture where the duct has bends, just to show it's possible.

Does Ajb really need or want to discredit you? At least I have received no such message from Ajb. And, well, I feel he's really patient and even-tempered.

Hello nice people! Fractional distillation is accomplished by varied apparatus: http://en.wikipedia.org/wiki/Fractional_distillation http://en.wikipedia.org/wiki/Spinning_cone http://www.solvent--recycling.com/spinning_band_packed_column.html but I haven't seen precisely the one I imagine: The rotating disks expose a good area of liquid film for evaporation and condensation, while the pools are separated excepted for narrow pipes that avoid diffusion. This permits one temperature per pool and disk, and hundreds of disks are feasible. Thanks to the good stage separation at the liquid and the vapour, the theoretical separation efficiency must be attained - which competing columns with many stages don't. ---------- The rotation axis is essentially horizontal; a slight tilt can let the liquid flow gently in the direction opposite to the vapour, possibly with active valves at the pipes - or use pumps. Limited clearances between the disks and the upper part of the vessel shall minimize vapour diffusion between the stages - use labyrinths or even seals if you prefer. Active valves at the liquid can regulate to zero the pressure differences between the stages. The vessel can resist over- or under-pressure. Adding a carrier gas to the vapour would allow the liquid to evaporate gently, without bubbles: this makes evaporation more selective. The disks can be corrugated or sintered for increased area. The apparatus can have several feeds and exits as usual. ---------- Take 2mm thick stiff metal if the disks are seriously wide, then you can stack them at 8mm intervals for instance, which means 1000 disks and separation steps in an apparatus only 8m long - this is a difference with competing methods, the reason why I suggested the use for difficult separations. Other methods like particle beds can have more steps but don't separate properly the liquids at each step. One apparatus can be flexibly divided into several sections aligned, with warmer and cooler ends alternating between them, and many inlets and outlets. That way, when you don't need 1000 successive separation steps but 10, you get the throughput of 100 apparatus in parallel - or the combination you prefer. Now it looks compact even if you evaporate without boiling. The helices at the shaft between the disks, to prevent mixing the liquid trickling from adjacent disks, don't need to be machined in the shaft; spring wire fit around the shaft should suffice. ---------- What uses? I expect the rotating disks to evaporate and condense the compounds less quickly than other methods do, but: - The gentle process, without spat nor local pressure and temperature fluctuations, keeps the evaporation selectivity; - Hundreds of disks cumulate their selectivity; - The process wastes very little power (one evaporation heat for hundreds of repeated steps) so it can be upscaled; - The horizontal axis eases upscaling as well. Hence I hope distillation by rotating disks may find some use where compounds are difficult to separate. Marc Schaefer, aka Enthalpy

Oops, I'm late here... Here a suggestion of how the ambulance could look like (sections are odd, don't get fooled): It's tall enough that the medics can stand, and permits to walk around the beds. The doors could slide to the roof instead, if durable enough - check how fire engines do it. On this sketch the rotors lift the cabin by its floor. A dense truss to the landing sledge would strengthen the floor but prevent shock damping. As the rotors are not synchronous, they should be made as quiet as possible. Marc Schaefer, aka Enthalpy

That sort of things? http://vortexengine.ca/PPP/AVEtec_Business_Case.pdf

It does work, as is known experimentally (...sorry for the disappointment - inventor's daily life). One strong limit to desalination through evaporation is the amount of heat, hence the collector area, neeed to produce a bit of fresh water. One (already operational) improvement is to reuse the heat many times. Condensation of vapour releases the heat invested in evaporating, and that released heat serves to evaporate more water. Of course, temperature drops at each heat exchange, so it can't be done at +100°C everywhere: it takes pumps to establish a pressure drop, hence a temperature drop, across all cells - but electricity is obtained from Solar cells, for the smaller pumping power needed. That way, Solar heat can be used 10-20 times. Though, this is not the preferred way presently, because even if reusing the heat, vaporization uses so hugely more energy than the separation of water and salt really needs, which is very little. Meanwhile we have reverse osmosis (see Wiki) which takes just a few times more energy than the theoretical minimum and is convenient : affordable hardware, reasonable maintenance, compact... Reverse osmosis is so much better that even Solar cells to feed its pump are cheaper than light concentrators for evaporation. It's an industry meanwhile. You can try to put figures on vaporization, and reuse heat many more times (how?) to try to match the economics of reverse osmosis, but that will be hard. Improvements must be possible in the reverse osmosis apparatus: better membrane materials, processes to assemble the wide-and-thin membrane (it's a fibre) in a small volume and still allow water to flow easily, avoid dirt accumulation... Fun: mixing sweet and salty water does produce a little bit of energy. Someone has found a way to exploit that, a tthe size of an estuary, and one demo plant exists (in Norway?). I like your sketch, as it focusses on the essentials.

There is no matter at c, and slowing light below c won't make the photons fermions.

My long background was waves (radio, acoustics, signal) before learning QM, that helped me a lot. Conceptually, more than for the maths.

Are you a hangman? We have already had someone here asking where to shoot in the brains to kill quickly, before two inmates inTaiwan were executed that way.

Hi Key010123, welcome here! Please forgive my nonconstructive answer, but is research on the Ising model still useful in 2013? Meanwhile Mankind has observed exactly (you know, Weiss, Bloch, all that stuff) thanks to the proper apparatus what makes a ferromagnetic material, and very little "modelling" is necessary in addition to the observation... Why should time be invested in an a priori model that does not reflect the microscopic observations, does not make more accurate predictions, nor is easier to compute? I feel the usefulness has dropped quite a lot since the time of Ising, who had no observation capability at the atomic size. Present research is on spintronics, with ferromagnetic semiconductors.

These two are linked by a Fourier transform, yes. But I believe others are not. For instance the angular momentum components along x, y and z. If one is known, the others are not. I see no Fourier transform between them. More must exist, in the first line those that result from angular momentum, like the magnetic momentum in x, y and z.

And the stated m*V2/R is centrifugal, which compensates the centripetal gravitation force.

Cutting does not work for every species. For these species that can't make roots from a branch, I wonder if methods from genetical engineering work, like: inject in an egg the genes from an other individual to be multiplied. Banana trees may be multiplied by cutting. The fruits they carry are not necessarily all identical. At least for cherries, prunes... the flesh has the tree's genes, but the stone is a new individual resulting from two parents.

Oops. Taking 1/16 m2 as the cell area, not 1m2, the power is 3W, obviously too little to move the skateboard. So only a battery makes sense. If the skateboard is to be powered by Sunlight, then have a big panel at home and leave it there to charge the battery(ies). Or have a big one with you that you unfurl or deploy when not moving. I prefer to charge the battery on the mains.

You don't like the full interconnection matrix to connect many chips? This one is predictibly doable, as it uses established silicon technology - nice for a thesis. It has a clear interest. If your chip can connect 100 or 1000 Core processors, server manufacturers will want it. Some sort of Xeon processor that has already a fast serial link. If no money is available for a prototype chip, you can breadboard a smaller demo with an Fpga. Or even, simulate the chip.

Second try with an other set of figures... It needs absolutely clear weather at a sunny location. Any cloud divides Sunlight by 100 and stops the skateboard immediately. Trees as well. The user wears on his chest and back two panels of 0.25m*0.25m and 10% efficiency to be half-way affordable. At 45° to Sun's direction (it can be high in the sky), they produce 50W. This must suffice for a well-designed skateboard, since an occasional cyclist produces 200W in an effort. I feel a battery is absolutely necessary, and the user must also be able to move the skateboard without added effort if no electricity is available. Then, I wonder if Solar cells bring something to the battery, which can be charged on the mains. Alternately, the user can have the Solar cells at home and move only the battery with him. Here we get the same situation as a bicycle. They have batteries but no Solar cells. What I doubt is that customers will pay expensive Solar cells to get a very unreliable means to move, subject to any slight disturbance.

Thanks for your interest! Cutting, as a vegetative propagation, does reproduce the same individual. Though, not every species is capable of it. Cloning might then be an alternative to get a whole copy (including the roots) of an individual. As the operation would be done for each new tree, it would demand a very low cost. Some simple genetic operations are made for calf, but a calf is ten times more valuable than a tree.