Enthalpy

I know that problem. I do not know the answer. I had hoped you wouldn't notice it and bring it in the discussion. Gasp. The situation as I see it: Just "positive charge carriers" is the least pleasant common answer, because the only mobile particles are the electrons, so holes behaviour must be explained in terms of electrons even if the reasoning is less direct. I got only that explanation from my professor, and he couldn't answer why in P semiconductors holes drift to the same side as electrons would do in N semiconductor. Later I got the less bad explanation of "electrons have a negative mass hence holes behave normally" and was satisfied with it until recently. I haven't seen a better one, despite both are flawed. "Positive charge carriers" is a simpler one but isn't right. I know an other objection (or an other formulation of the objection) to the "holes have a positive mass" explanation: We know the flow direction of the main current, it's the same whether the electrons have a positive or negative mass. The Lorenz force doesn't depend on the electron's mass, and with no current taken from the transverse electrodes, the electric field corresponding to the Hall voltage compensates the Lorenz force. As the force by the electric field doesn't depend on the electron's mass neither, the Hall voltage shouldn't reverse where electrons have a negative mass. So both common explanations are flawed, or at least incomplete. Maybe it's a matter of speed versus acceleration. Or of velocity near the conduction band minimum compared with the speed around the minimum. Or of aliasing to the Brillouin zone. While the issue is interesting, I don't plan to invest time in it. This is not the only flaw in the usual models about electron conduction in semiconductors and metals. The heat capacity of metals is commonly explained by lattice vibrations plus a negligible contributions by the electrons because only a few ones are near the Fermi level hence can move and store kinetic energy, BUT Hall measures tell that about one electron per atom is mobile in a metal. The bands are not the free electrons' parabola because of interaction with the lattice, that's clear and even unavoidable. At the valence band maximum, the (valence) electron's wavefunction [but I like to say shortly "the electron"] changes its phase by 180° from one atom position to the next. Near the maximum, the phase differs a bit from 180°, so the wavefunction changes less abruptly, and the electron's energy is smaller. Smaller energy from more momentum means an inverted curvature and a negative mass. Real life is in 3D, one should distinguish the directions of the crystal which indeed change the shape of the bands. Also nasty, at least one semiconductor has the maximum of its valence band at nonzero wavenumber - excentered in the Brillouin zone. Other explanations exist, one being that we have folded the free-electron's parabola over the Brillouin zone, so what was a normal increase of energy when nearing the 180°-per-atomic-distance wavenumber is now around the zero wavenumber. Depending on one's background, call it aliasing (signal theory) or stroboscopic effect. Not wrong, but too short: just above that wavenumber, the energy of a free electron continues to increase, while after folding we should have obtained a flat top at the valence band. Because of that, I prefer a wavefunction resulting from orbitals interactions rather than from free electrons; software models for bands also combine orbitals. What stands firm is that the bands can be observed (more or less), they fit rather well what computer models tell, and their (often inverted) curvature also fits the measured Hall voltage in semiconductors and metals.

Yes. I hesitated at it, and got discouraged by the alleged brittleness. Though, I haven't tested it with my own fingers. I'd prefer the balls to accept significant crushing before the lithium gets exposed, and PP is a candidate for that. I've also had an exorbitant price for PMP in the past, but I suppose it was dishonest. The choice of processing temperature looks rather harmless if lithium is injected in a polyolefin sphere: I suppose it could be done at room temperature, or with very little heating. On the other hand, polyethylene is commonly injected around +200°C which wouldn't fit a lithium sphere, unless thermal inertia does a trick. A lower-melting polyolefin would ease this option of shell-injected-around-lithium. Or if not, back to the liner like Parylene, but thick enough to protect the lithium a bit.

Personally, I wouldn't use the hydrogen in a combustion engine. The efficiency is limited, a combustion engine lacks flexibility (minimum rpm for instance), it's heavy. I feel much better to use the hydrogen in a fuel cell to power electric motors: efficient, silent, flexible. One difficulty of burning hydrogen is that is always detonates. A slow combustion is very difficult to obtain, and even with continuous injection of hydrogen and oxygen or air, the flame uses to be a succession of local detonations. Quite destructive for an engine. An other difficulty is that it leaks easily. Worse than other gases. Hydrogen storage is a BIG difficulty, with no real good solution up to now - whether for a combustion engine or a fuel cell. Also, any internal combustion engine that burns a gas is inherently more difficult, because the fuel volume must be compressed too, which costs energy. Compressing 2H2+O2+4N2 costs 7/5 as much as with a liquid fuel. But if the hydrogen is stored under pressure, you may inject it after the air compression in the cycle.

For a DC motor of given W or kW size, it's much a matter of acceptable losses. In the MW size, the flux created by the rotor, and the difficulty to compensate it exactly with the special stator winding, is one limit. If present, the commutator is always a limit at any size: look at a car starter, which accepts big losses for a short time to produce much power in a small volume and mass. Its commutator is huge as compared with the magnetic circuit. When designing a DC machine, the commutator gets impractical or a huge drawback over few MW. At higher power, machines use to be three-phase, and if needed (say, to vary the speed), they have power electronics.

Link provided. I have provided timestamped evidence that I proposed the ideas. Nobody has provided evidence that someone else did. For any patent office, I'd be the inventor.

NaK is liquid below room temperature, Galinstan too. "41% Cs, 47% K, and 12% Na has the lowest melting point of any known metal alloy, at -78 °C" (Wiki about caesium) 78%K 22%Na resists 410nohm*m at RT. Hg resist 961nohm*m at RT. I don't have at hand the resistivity of Ga-In nor Ga-In-Sn (Galinstan). Compare the heat conductivity if the electric one isn't available. NaK reacts with water and humidity. Hg emits toxic vapours. Ga-In and Ga-In-Sn are the most civilized. Consider that about any liquid metal is corrosive to solid metals and to some ceramics. For instance Hg amalgamates Al and most metals, Ga botches steel just by contact, and so on.

One difficulty to polish polymers is that their molecules use to be larger than the irregularities tolerated by optical polish, so if the polishing process rips off macromolecules, the surface keeps optically rough. Also, polishing is often done using materials softer than the target, like cloth against metal, and softer than a polymer excludes every abrasive.

A computation of the effect of a gravitational wave on the light in an interferometer is in Chap 1.4 (Pdf p18/149) of "Seismic Isolation for the Test Masses of the VIRGO Gravitational Wave Antenna" by Claudio Casciano.

No symmetry is an explanation not so rare. I guess many authors and journalists still call it "paradox" by replicating other texts, and possibly to attract readers. Much like Schroedinger's cat is plain garbage, all serious people know it, but this story is still repeated from book to book.

Heat is a good solution. An other permanent magnet wouldn't demagnetize a Nd magnet because it wouldn't be strong enough. Nd magnets keep their full magnetization even it assembled head-to-head so no flux passes through. It makes designs using them much easier than with older magnets like AlNiCo. A strong alternating and damped magnetic field would demagnetize a Nd magnet. It needs like 3T hence can't use a permanent magnet nor a magnetic circuit. The spool that creates this induction consumes several MW which can be provided by the discharge of a really big capacitor, a fraction of m3; the oscillating current suggests a nonpolarized capacitor which is even bulkier. I did nearly this to magnetize SmCo magnets. An oven is easier.

I don't see a strong relationship between negative mass and mass tensor. In most semiconductors with indirect gap, including silicon, the valence electrons near the band edge have an isotropic negative mass (or rather two masses, light and heavy holes) while the conduction electrons near the band edge have a positive mass that isn't isotropic, at least in individual valleys. The electrons' mass can look isotropic if all valleys contribute as much to the conduction, especially if the crystal isn't stressed. Yes, the current is explained by electrons only. It's the only mobile particle in silicon anyway. It's only because the electrons' mass is negative near the valence band's edge that we introduce holes. The mass is a tensor because the material does that. In each direction of a minimum of the conduction band, the Fermi surfaces are ellipsoids rather than spheres. In gallium aresenide for instance, the conduction band minimum is centered in the Brillouin zone, the Fermi surfaces are spheres, and the electron mass is isotropic.

At least one plant in China produces heat with waste. Difficulties: On a big scale, you'd connect the future victims to the radioactivity source with hookahs. Or convert the heat into electricity, but the power is small. Fission produces 200MeV per U burnt in 1 year, plus two radioisotopes that produce 1MeV in 30 years. At equilibrium it must be under 1% of the fission energy, not worth the engineering. On a small scale, near the use, you'd still need a radiation shield almost as thick as with a big source. It exists for space probes in the form of 238Pu (which isn't waste) because this one emits no gammas, so thin shielding is enough. The other nuclides, including the 90Sr waste, emit gammas. Either themselves, or their childrens do, or the betas they emit do it when braked by the radioactive material or by the shield. 90Sr has been used to power lone lighthouses in the Soviet union, and despite some thick shielding, two siberian hunters who had spent the night around the heat source died subsequently from the radiations.

Thank you! Li melts at +180°C, Na at +98°C only, polyolefins are injected at a mild temperature that makes them softer.

I need to clarify the logic, yes. If electrons conduct the main current, the Hall effect sweeps them to one side. If holes conduct the main current, the Hall effect sweeps them to the same side. And since their charges are opposite, the sign of the Hall effect depends on the charge of the (main) carriers. But holes conceived only as the absence of electrons do not suffice: Holes are just a simplification to help reasoning. It's still electrons that move, whatever their density, the band filling, and their mass. A hole moving in one direction means that an electron moves in the opposite direction. When the Lorenz force sweeps an electron to the right, the hole sweeps to the left. So if the electrons still behaved normally in, say, a P semiconductor, we would observe the same sign for the Hall voltage as in an N semiconductor. It is the electron's negative mass, in situations where the band's curvature is inverted like in a P semiconductor, that gives the hole a positive mass, and lets it behave as a normal particle but with a positive charge, explaining the sign of the Hall voltage. This also tells that the hole is a useful idea where the band curvature in inverted, rather than when a band is almost full. And indeed, holes are commonly defined in metals, where they explain the sign of the Hall effect when needed, exactly as they do in semiconductors. I haven't found within a reasonable time a real band diagram for a metal with mainly hole conductivity. But at least the (heavily simplified!) sketch there helps understand: http://www.doitpoms.ac.uk/tlplib/semiconductors/energy_band_intro.php The band overlap tells it's a a metal (there would be many mode bands, and the Fermi level very far from their minima and extrema). Some bands have a normal curvature near the Fermi level, and the electrons have a positive mass there, usually not their mass in vacuum. Other bands have an inverted curvature near the Fermi level, the electrons there have a negative mass, so holes are more useful. Both electrons and holes conduct is most metals. The main current as well as the Hall voltage results from both, with varied contributions.

Hi Nikolai, welcome here! You don't need to explain why the wave disappears at the screen, because it doesn't. This is a common but wrong interpretation of QM. The electron interacts with some particle (probably an electron) at the screen, it does so as a wave (more accurately, a wave describing both electrons at once). What we need is that when the incoming electron interacts with a single other at the screen, some properties of the electron don't split, like the charge. I'd suggest you to check images by the atomic force microscope. They result from observing the same electron pair all the time, all over the orbital. https://www.zurich.ibm.com/st/atomic_manipulation/pentacene.html You could also meditate the X-ray diffraction by crystals. There, the photon isn't destroyed (at least when it contributes to the diffraction pattern) and it interacts with many atoms.

Wow, half a dozen people scouring the Internet and spending their time here, just to claim that I brought nothing. This attempt defeats itself. I read happily that you spent your time searching for radio-controlled cranes and excavators and only found a pump truck used for concrete. Just like you didnt' find any mention of a concrete pump used to dump water on the spent fuel pool. Just as I'm equally happy to read that of course, other people thought at it before, but are not allowed to tell it. Just like my grandfather invented Crispr-cas9 in 1930, but the government decided to keep it secret. Conclusion: I did invent the radio-controlled cranes and excavators used at Fukushima. Just like I invented the concrete pump dousing water on the spent fuel pool there. And if not, bring evidence against.

Strange, what are you doing together with the infernal trio?

That's why I recommend the non-halogenated Parylene. Do you see other difficulties with that particular coating (or with others I suggested)? Woud lithium prevent the polymerization or induce other reactions? Other alkaline metals have a strong action on alkenes, used for instance for metathesis.

This is a common description of holes, but some details are usually imperfect. If one imagines electrons have a positive mass even where the band's curvature is inverted, then in the Hall effect, the electrons will move to the side deduced from positive electron mass, and the holes move to the opposite direction, and since the holes and electrons have opposite charges, the sign of the Hall voltage would remain the same. The very reason for opposed Hall voltage is the negative electron mass, for instance near the maximum of a valence band, because this negative mass sends the electrons to the opposite direction. The negative mass is a consequence of the crystal, sure. And when the electrons have a negative mass, it is useful to introduce the idea of hole, because the hole has then a positive mass. A hole current is just an electron current in the opposite direction. In a valence band too. Now in a metal, whenever a band has an inverted curvature near the Fermi level, the electrons there have a negative mass, and we prefer to speak of holes. This happens at many metals and it doesn't need an almost-full band. The situation is often more complicated because metals can have several bands that intercept the Fermi level, and with varied curvatures.

The ones I tried to bend became white and opaque.

Thanks Swansont! Just one other example is the cooler for the #4 spent fuel pool, since dousing with more and more water wasn't sustainable. I wrote "Liebherr manufactures truck coolers of the proper size" on Mar 29, 2011 and immediately, the government proposed to ship some to Japan. This proposal wasn't adopted, but it shows that my suggestions were read. One nice report by Areva, possibly the one I had in mind http://hps.org/documents/areva_japan_accident_20110324.pdf on page 22 about reactors 1 and 3 "The reinforced concrete reactor building seems undamaged" have a look Nor is it reasonable from Areva to speculate about the reactor's status while noone had firm information. At that date, only Tepco was on site. Areva's drawings are merely speculations, and titling "accident progression" doesn't help. Did they have any kind of evidence that the drywell's tap was still on place on #3?

I know someone else can make the same proposals. But I feel my suggestions less immediate than that. Radio-controlling excavators and cranes isn't done usually, and I had not heard about it before. A crane driver would improbably have suggested that one. The interpretation of the 38Cl didn't exist on the Internet before I told it. Quite the opposite, several academics tried to model how much 38Cl would be produced depending on the fuel's condition and position, to inconclusive results. Other proposals were accepted, less spectacular than these. It took the reaction time (by people in a hurry!) before my suggestions were applied on site. The time to commission the Antonov after I proposed the concrete pump, the time to adapt the excavators, and just the time to read my intepretation about radiochlorine. Other people can (and often do) have the same ideas as I, but improbably at the same time.

One more primer option is Parylene. Together with halogenated variants, it serves as a conformal coating against moisture on electronic boards. https://en.wikipedia.org/wiki/Parylene Heat splits the precursor to a diene which polymerizes when touching surfaces near room temperature, leaving no voids. Used commonly on metals, ceramics and polymers, but often after a first siloxane layer probably unsuited to lithium. Since adherence isn't vital at the float, I hope to spare the first layer. What lithium does to the monomer is unclear to me; a bit of untypical material is acceptable if the outer material is sound. The price is a drawback: up to 1k$/kg for the precursor and one day to deposit 0.1mm, after what handling and processing is easier. The coating chamber can process many balls. Some kind of moving support like the previous rolls must avoid shadowed locations. ---------- I like increasingly a polyolefin hull on the lithium. Low density permits several mm thickness, and then polyethylene or polypropylene resists shocks, deformations and tearing better than thin metal does. If a polymer is injected around a lithium ball, a shell in two successive parts looks easier. A primer like parylene must ease the operations. Other polyolefins use to need a higher injection temperature, but lithium limits it. ---------- Supposedly, lithium can be injected instead of cast, much like a polymer: heated to a creeping solid rather than a liquid, with much pressure to inject it. Material pressure fills the mould better, preferibly in combination with vacuum. Production is faster as the part is obtained solid. Solidification can make internal voids and a less accurate shape, which injection improves. The shape is more accurate. Lithium injection could be made in the protective hull then. The hull would be nearly complete instead of two halfs, with the injection hole tapped when the lithium is cold. Marc Schaefer, aka Enthalpy

It was a report by Areva, published on the day following the first explosion. Why assume something like this? Any reason for it? I proposed a concrete pump truck to douse the nuclear fuel, there on Mar 17, 2011 http://saposjoint.net/Forum/viewtopic.php?f=66&t=2657&start=60#p31130 the trucks were sent thereafter and used http://saposjoint.net/Forum/viewtopic.php?f=66&t=2657&start=100#p31257 I proposed to add remote controls to hydraulic heavy equipment, there on Mar 17, 2011 http://saposjoint.net/Forum/viewtopic.php?f=66&t=2657&start=60#p31131 and it took about a week to make the adaptation before using them on site. I told there why the 38Cl observation was a mistake http://saposjoint.net/Forum/viewtopic.php?f=66&t=2657&start=160#p31368 while nobody else could make a sensible interpretation of it, criticity again or not. and so on.

One fundamental reason for irregular filling is that electrons repel an other, so the energy levels you observe by, say, having all 3d and 4s void and available for one single electron do not apply for further electrons, when some are already present as 3d or 4s. An other, less simple reason is that wavefunctions for electrons must be antisymmetric, and this influences the orbital shape a lot. The mere presence of an other electron changes the shape of the other orbital - provided you want to consider orbitals as functions of one single location. Have a look at ortho and parahelium, which differ by the spin alignment of both electrons: http://www.ipf.uni-stuttgart.de/lehre/online-skript/f40_03.html and http://hyperphysics.phy-astr.gsu.edu/hbase/atomic/grotrian.html#c1 You observe that Cr and Cu put one electron more on 3d and one less on 4s. (click to enlarge) So why would Ca organize its electrons as [Ar]4s2 while, with just one proton more, Sc+ would put them as [Ar]4s3d? It could possibly be that 3d is, as a mean, nearer to the nucleus than 4s, so one proton more favours 3d. I'm not quite convinced because s orbitals have a density at the nucleus while d have zero density there. Less simple: chemists are interested in atoms and ions in crystals, solvents... rather than alone in vacuum, and 3d may be more favourable in the context.