Enthalpy

Most (all?) metals have at the same time many holes and many electrons, which is possible because the Fermi level passes through several bands which have opposed curvatures. Big conductivity is found in metals, as they have more electrons or holes that even heavily doped semiconductors. If the valence and conduction bands are well separated as in semiconductors, equilibrium wants either electrons or holes but not many of both at the same time. Though, a significant density of both exists far from equilibrium, as limited by recombination, for instance in a laser diode or in a saturated bipolar transistor - but the carriers are never as dense as in a metal. I can't think of a means to suppress recombination. In many devices, designers seeks to minimize it: nonradiative recombination in light emitters, pair generation in blocking diodes... but the material itself shows a minimum rate of generation and recombination, even when not overshadowed by parasitic processes which are difficult to minimize. In short: if copper and silver don't suffice, go to superconductors.

Thanks for your interest! I've already seen more speculative ideas than thin-film deposition.

Dear all, here's a suggestion to deposit metal catalysts on a thin supporting film. The resulting specific area is favourable, one machine can deposit about any metal and works quickly. The machine resembles the ones that deposit aluminium on polyester film for candy wraps and space blankets. It can be adapted from such a machine, new or second-hand. The machine passes the supporting film between two mandrels and deposits meanwhile the catalyst metal under vacuum. Covering both sides of the film is better, at the same pass even better. Ptfe, Pe and Pp resist many chemicals and may be the supporting film, but they can't be very thin. Nickel, cobalt and alloys can be electrodeposited as standalone films with 8µm thickness and up. Tantalum and niobium can be laminated but not as thin. Thin tantalum deposited on supporting nickel-cobalt would improve the chemical resistance, and the catalyst metal could come atop. Ptfe, Pe and Pp need some surface treatment before the catalyst adheres. A supporting metal film probably needs cleaning. Doing it in the same machine (by plasma?) without breaking the vacuum or low pressure thereafter seems better. Traditionally for semiconductors, an electron gun evaporates the varied metals, even refractory ones. Sputtering is a more recent source, also flexible. A nanosecond pulsed laser should be considered. A machine for candy wraps takes coils over 1m tall, so stacking several souces of catalyst metal seems better. Measuring off-the-fly the deposited thickness at various heights to control the sources is advantageous with expensive metals. Observing the light reflectance at few short wavelengths may suffice. To let the reactants, products and solvents through, the plies must be separated, for instance with a thin wire, as they are stacked or rolled. Alternately, a rolling mill can make corrugations or bumps in the films, possibly at every second ply. If the catalyst coil or stack stays loose, being held together by a loop of metal for instance, it's easier to clean and regenerate - advantage over a sintered ceramic. When seeking compactness, the channels would be thin too, hampering the flow of liquids. An answer is to provide a set of additional wider ways, possibly cut by laser across the stack or coil, to and from the thin channels - possibly as a tree, like animals have arteries, arterioles, capillaries, venules and veins. This applies to sintered materials too. Marc Schaefer, aka Enthalpy

Lightning as a source of Transcranial Magnetic Stimulation had been proposed in 2008, hence before my last post here: https://en.wikipedia.org/wiki/Ball_lightning#Transcranial_magnetic_stimulation whether this shall explain ball lightning (new observations exist meanwhile) as a mere perception is not my point here.

A simpler upper bound on the mean deposition rate of calcite: On the pictures, we see less than 175mm calcite added on the construction over 175,000 years. That would be mean <1µm/year between the construction and present time. The rate varied over this time, and is faster at the stalactites. This tiny deposition rate re-opens the remote possibility of terracotta walls. Would have worked better than raw clay, and would explain the traces of fire if necessary - but the oldest known terracotta is 150,000 years younger, from the Sapiens Sapiens.

Here's an estimate of the calcite accumulation rate. Speleologists must have better, directly observed figures. Due to vegetation, groundwater can contain much more carbon dioxide than rainwater: 3mmol/L, according to Carbon Dioxide Equilibria and Their Applications, By James N. Butler. This groundwater can dissolve as many 3mmol/L of CaCO3 as bicarbonate and release them as calcite, or 0.3g/L. A reservoir accumulating water drops at 2L/h (100 drops/s from many stalagtites, enough for 20 people) over 20m2 would accumulate calcite (2711kg/m3) at 0.1mm/year if it were uniform - should be more where the drops fall and less at the walls. Walls reinforced with stalagmites and covered with unfired clay need frequent maintenance, so at that rate, calcite wouldn't have accumulated on the walls. But over 20 years, some 2mm calcite may have accumulated at the basin's bottom, with a distribution that hopefully differs from water flowing away. If finding the right calcite layer, this would be an indication for a basin. Layers of calcite depend on each year and their stacking tells a date. I feel easier to check first the composition of the construction stalagmites' surface, which has a different colour. Does this result from fire? Or rather, did some mud, for instance walls' clay, diffuse into the calcite? The bingo would be if the diffused mud has a composition not found nearby in the cave, that is, if the humans have brought clay for their construction.

You should check what air throughput a turbofan needs.

How? An aircraft carrier is protected by its planes, a submarine, some frigates including antimissile ones. Which one shall stop a 2t fléchette of solid steel falling at 5000m/s and 45°? And then, stop 50 salvoes of 20 fléchettes? And, yes, a submarine is better protected than an aircraft carrier. Or much smaller surface warships would be targets of lesser value, hence would be less at risk. I can't agree on that. US and European countries have shortly a small worry with terrorism, which is numerically very small if compared with a more standard war, and must be soon over. The real threat is a true war, say with Russia. If some day the US decide that Nato is obsolete, or Russia's friendship is as important as Europe's, then Poutine will invade the three Baltic republics and parts of Poland without a doubt. Then the rest of Europe, without a military coalition, without a military or political leadership, will have to decide: go to war or accept the blow. While drones look useful, up to now they were meant to bomb Yemen and Pakistan. They have no defence, no agility, only the much overstated stealthiness. Useless against Russia. Typically a result of three decades planning asymmetrical war, and this is damned dangerous.

Hello everybody... This story will be fabulously, incredibly, horribly expensive for sure. Whether it kills EDF, the French near-monopoly electricity producer, and puts France in a Greek situation, will be seen in a few years. Context: in the 70's, EDF is the state-owned monopoly electricity producer and distributor. The government orders to build nuclear powerplants everywhere. Besides the dependence on Africa for uranium and besides a few core melts, France gets electricity. These reactors are 40 years old, some should have long been replaced, but Areva can't develop the EPR reactor, so nothing is done. The EPR building sites abroad will cost delay penalties exceeding much the sale price: a commercial company would be long closed, but the French governement injects taxpayer's money, orders one more EPR for France and "sells" two to Britain (that is, EDF buys and operates), and lets EDF "buy" the reactor activity from Areva for several G€ despite it won't ever make any profit. Meanwhile: Keep the old reactors and hope they don't burst soon. EDF is already overloaded by a huge debt, possibly 70G€. It has no sufficient provision to build new nuclear reactors (200G€? At Hinckley Point's price it's rather 500G€!). It has no money to decommission the old reactors, and has never taken one apart and cleaned the site. It doesn't plan to pay the storage of radioactive waste - taxpayer's money directly of course. Even the upgrades to operate the old reactors 10 years more is to cost possibly 50G€. In front of this obvious nonsense, all successive governments have done the same: nothing. They injected a few G€ here and there so the problem appears after they leave office but worse. No reasonable sales price for the electricity ("cheapest in Europe" but EDF sinks under its debt, and anyway the gross price is cheaper elsewhere). Recently, the Gov even perceived a dividend from EDF. EDF builds two 1.6GW EPR at Hinckley Point for 18G£/pair or, at mean 2*1.3GW: 8.2€/W. In the 90's, one 1.3GW nuclear powerplant cost like 0.3G€, now it's almost *100! Just to compare, Dong Energy bought 300x 6MW wind turbines to Siemens for 2.5G€ http://www.siemens.co.uk/en/news_press/index/news_archive/siemens-to-supply-300-wind-turbines-to-dong-energy.htm and since offshore the mean load is 1/3, the acquisition cost 4.2€/W. That is, just the recent injection of 9G€ of taxpayer's money into Areva and EDF http://lexpansion.lexpress.fr/actualites/1/actualite-economique/nucleaire-l-etat-actionnaire-a-la-manoeuvre-pour-soutenir-la-filiere_1867961.html would have bought wind turbines equivalent to 2.1GW, more than the unfinished EPR at Flamanville. And the 18G£ for Hinckley Point would have bought wind turbines equivalent to 5.1GW: as much as 4 EPR rather than 2 planned there. The price per MWh is also cheaper for wind energy than for Hinckley Point's EPR. What's next? If some French government takes action and lets build nuclear reactors of foreign technology, it may cost 200G€ over the coming 10 years. Whether the consumer or the taxpayer is shorn, this money won't be available for other expenses, so the country will be poorer. If this is done 10 years later, it will cost 50G€ more to maintain the old reactors in activity. Add waste storage and decommissioning to this. Replacing by non-nukes looks unthinkable in France. But the most probable future is that every government will do exactly what the previous ones did: nothing. Until one plant has a catastrophic accident, or until EDF is bankrupt - which may happen sooner than expected, and add >10% GDP of new public debt, putting France at once in the near-junk category at the side of Italy.

While an aircraft carrier in its aeronaval group projects a formidable destruction force, it is effective only against low-tech enemies. For having fought and imagined only unsymmetrical wars in the last decades, the US and Nato members have forgotten what their true role is: protect against strong enemies. Russia can again develop superior technology (their fuel-air bomb distributed by a Katiushka salvo exists nowhere else), china progresses, Iran has centrifuges better than anywhere and cavitating torpedoes. Against a high-tech enemy, an aircraft carrier is a target, not a weapon - just like any big surface ship. One possible anti-carrier weapon is a kinetic energy penetrator, like that but bigger: https://en.wikipedia.org/wiki/Kinetic_energy_penetrator Instead of 20kg launched by a battletank cannon to arrive at 1000m/s, the 2t impactor would arrive at 5000m/s and >45° and be launched from 2,500km distance by a rocket carried on a truck or small boat. The propulsion, design, materials, reentry of such a weapon are trivial. Guidance is not, but is similar to any missile travelling over the atmosphere. Being essentially solid steel and fast, such an impactor is very difficult to destroy or deviate. Its penetration power exceeds much the need against a warship, so the head can instead deliver 20 penetrators, or the truck can launch a salvo of 20 smaller rockets. The penetrator nose's shape too may spread shrapnel to increase the hole's radius at the warship's bottom. This example of weapon looks perfectly deadly, easy to conceal, very difficult to stop - and it is 10,000 times cheaper than its target and much cheaper than its interceptor, so a saturation attack is reasonable. Hence my claim, that all big surface warships are obsolete.

Hello everybody! You may know (but are welcome to ignore) that France has already had trouble with the security of bank chip cards. Well, it didn't really improve, whatever the reason is. In 1984, the bank card association chooses an RSA key length of 320 bits, far too little. Whether the government interfered it everyone's guess. In 1988, academic experts warn that the key is too short. Neither the association nor the government react. Additionally, the symmetric encryption has a 56-bit key: too short as well, broken efficiently in 1998. In 1998, the factorization record is 430 bits, but the association hasn't moved. An enthusiast, Serge Humpich, factors the 320-bit key of the French bank cards association, and shows the association that he can forge bank cards that would be usable for bad purposes. The French state jails Mr. Humpich and censors the Press about it, as if the real enemies had needed newspapers to know the weakness, but makes no serious technical decision. Presently (end 2016), the RSA key length is 768 bits on French bank cards, waooo. When this was decided, the factorization record was 512 bits, and experts warned not to stay too long with 1024-bit keys. The present factorization record is 768 bits too https://en.wikipedia.org/wiki/RSA_numbers#RSA-768 and once a big machine has factored the association's key, any fake bank card can use the factors. Well done again!

From the Beeb: the UE has imposed to compute and store hash values for all images that shall be censored http://www.bbc.com/news/technology-38207977 Facebook, Microsoft, Twitter and Youtube collaborate. It's the same process that France and others had already imposed to all Internet access providers. Each and everytime you and I put a new image on the Web, someone in a poor country (often the Philippines) has to check it, and if for some reason a government dislikes it, its hash value lands in a red list. Obviously, the permitted images get screened and hashed too since this avoids the repeated human screening. And the same happens for each and every new Internet address - for instance a new message on a forum. And as soon as artificial intelligence gets half-way as efficient and cheap as the Philippino, it replaces him. Of course, the UE tells this will avoid "violent or extremist material". But once the process exists, it is able to censor whatever a government and its agencies want, hence it will serve for arbitrary censorship. This is a basic, fundamental and unavoidable law of all governments. You can be certain that copyrighted material will be blocked that way from uploading - it must already be the case. Just like everything the government or its agencies dislike.

British MPs want to develop energy storage because renewables are intermittent: http://www.bbc.com/news/uk-37664880 which is obvious logic and will become an ever stronger need as the fraction of renewables increases.

MHD is little known because its poor results have prompted little investigation (unless some succeeded in unknown submarines), so I expect no off-the-shelf software for it. Even if the naive models with uniform magnetic, electric and velocity fields combined with fluid resistivity did work, MHD would have a quite poor efficiency - but these models are known to be very wrong because the electric currents create turbulence in the flow. One expert for MHD is Jean-Pierre Petit, but he's long retired and speaks little English. Don't let his reputation of crank stop you. https://www.jp-petit.org/science/mhd/mhd_fr.htm https://en.wikipedia.org/wiki/Jean-Pierre_Petit One demonstrator boat has been built by Mitsubushi Heavy Industries https://en.wikipedia.org/wiki/Yamato_1 so in 1991, knowledge was available there, but not necessarily for disclosure. 15km/h with superconductors in helium isn't so appealing.

Hydrogen and fuel cells make good aeroplanes... Other people believe it strongly enough to have developed some. http://www.aviationpros.com/press_release/12264576/hy4-maiden-flight-of-the-hydrogen-powered-airplane This four-seater is still rather slow (150-200km/h) and resembles more a motor glider, but it claims already 750-1500km range, much for this plane category, and a strong advantage of fuel cells. No word about sales, so it must be a demonstrator rather, but to my opinion, its performance is market-ripe. And the members of the team (a wide consortium) speculate loudly about commercial transport soon.

You are deeply underestimating the difficulty of making inventions. This is the usual case of non-creative people. And here I even feel the usual aggressivity of non-creative people who tell "anybody could have invented it" after I did. In this case, I have even proofs that I proposed the ideas before they were adopted, and you failed to show any other source for the ideas, but you still try to denigrate. If it was so obvious, why didn't you propose the solutions?

Permanent magnetic and electric dipoles don't interact. B (and H but not M) result from the magnetic dipole, E from the electric one. B as well as E are depicted there https://en.wikipedia.org/wiki/Dipole The Poynting vector isn't used for static fields because it's not useful. From its formal definition of a vector product of E and H, since the parallel dipoles create E and H fields parallel everywhere, the Poynting vector is zero everywhere here. When you write "dipole" it usually implies that it's insensitive to external influences, so admitting that the toroidal magnet has a permeability of nearly one (almost true for ferrites and rare earth, wrong for AlNiCo) the fields just add. Generally, the flux of one source can't be determined, only the flux of the sum, but here a dipole has no size hence the large magnet puts no flux in it, so we could say that the dipole's flux is unmodified.

Very wrong.

Your description is surprizing because the wires' colour is expected to change from one setup to the other. In case you don't know exactly what you're doing, pease keep your hands off HF. This stuff is really bad for your flesh and bones.

A centrifuge would be big to achieve 1g with a reasonable angular speed. It has definite drawbacks, as every object and person would feel a strong Coriolis force during any move. I wonder: for what benefit? Humans have already spent 2 years in true zero gravity, hence worse than on the Moon or Mars.

3 Tesla is a BIG induction. Even in a small volume, such an induction stores a big magnetic energy. The capacitor (bank) providing this energy plus the losses is bulky, like 0.2m3, and expensive. The coil and the circuit are difficult to design and build. So this isn't the good method. Heat your magnets instead.

Yes, I have to put time in other activities. I believe the analogy with alkenes and polyenes holds - in fact, I understand (or mis- maybe) polyenes by analogy with semiconductors, insulators and metals. The analogy is so deep that long polyenes need doping to become good conductors, and the absorption spectrum of dyes refects the multiple energy levels. Yes, the curvature is in the (h, E) space. Nothing observable easily in xyzt. What's the state of an electron, and what does Pauli's exclusion mean here? It gets complicated as soon as there are several electrons. The electronic "states" in a solid usually refer to a definite energy and momentum. By definition, such states extend to the whole solid. When the solid is the wire of a high voltage line, the states are 1000km long and 10cm wide. Definite momentum means indefinite position. These states, with definite energy, are useful because the Fermi-Dirac statistics tells that, in a band about 1eV tall and at a temperature of 26meV, and depending on where the Fermi level is relative to the band, some states are (almost) certainly occupied, other empty, and just a fraction of them are sometimes ocupied - this is where movement happens, for instance if an electric field picks an electron from a state flowing to the left and puts it in a state flowing to the right. It explains nicely why a full band in an insulator doesn't conduct. As an other advantage, we know from Fourier transform or series that any waveform is a linear combination of these states, so they're a good base. Though, these states are not the only possible base. One simple example: take the exp(+ikx) and exp(-ikx) states [*exp(iwt) implicitly]. You can write them as weighed sums of cos(kx) and sin(kx), so the complete collection of sin and cos for all permitted k is a base too, and not even a bad one as it's orthogonal too, so it's just equally correct to have one electron pair in each of these standing waves rather than a pair in each propagating wave. Pauli rule means that electron (pairs at most) occupy states that are orthogonal to an other. So not only is the choice of the base subjective to describe the waveform of an electron. It's worse: we have no other reason than human-rated simplicity to claim that the set of electrons fills one kind of waveform base rather than an other. The set of electrons below the Fermi level fills the available states, but we don't know what kind of states. Only after a successful interaction can we tell "the absorbing electron had such a state and now it has such". So "delocalized to the whole solid" applies to the available states which have a definite momentum. For other states, say orthogonal wavelets, the momentum would be less defined and the position better defined. And the electrons? Well, there is no reason to attribute them a set of waveforms rather than an other. In some cases - and this doesn't differ much from vacuum - we do have information about an electron's position. Say, if it has been injected in the conduction band from a deep dopant level: for some time we know it's near to the dopant atom. Then, the adequate wavefunction to describe it isn't one plane wave with definite momentum - but the wave can be described as a weighed sum of plane waves if this is advantageous. Or as a Gaussian or a sum of Gaussians, which is interesting because it keeps its shape during a diffusion process. ---------- As a sidenote, in the BCS theory for supraconductivity, two electronic states that propagate in opposite direction with definite momentum make a series of nodes and antinodes which, as the momenta are not exactly opposite, propagate, and the nodes interact with the charge wave of the lattice compressed or expanded by a phonon. Since the two electrons that can be put in this state are delocalized to the size of the solid, there is no need to "explain" how they should couple despite their repulsion. They aren't near to an other. ---------- Band structure from orbitals... Yes they do result from atomic orbitals, but that's accessible to software rather than qualitative or algebraic understanding. While electrons in a band don't result directly from atomic orbitals (and transition metals like Cu rearrange the electrons a lot) the orthogonality of all electron (pairs) still holds, including that delocalized electron waveforms are orthogonal to the electrons local to the atoms. Being already orthogonal, the available atomic orbitals are interesting candidates to define mathematically the delocalized states, but that's all. Heavy weighting and summing may be necessary, just like you don't find the original 2s and 2p orbitals of the carbon atom in a CH4 molecule. A striking example that the deep local atomic orbitals influence the band structure: C, Si and Ge have the same crystal structure and the same number of valence electrons, but the conduction band minimum has a different momentum for each material. This tells that simplistic models like the periodic potential are insufficient.

A permanent magnetic field, for instance Earth's one, is not attenuated by seawater. You can use the compass. An AC magnetic field is attenuated. At rather low frequency, when the distance is well under a wavelength, the attenuation depends on water's conductivity, hence on salinity mainly. If the distance clearly exceeds a wavelength, no pure magnetic field exists, but rather an electromagnetic field, for which the attenuation of E and B is measured and follows an exp(). Consider a few cm for exp(-1) at 1GHz, varying as sqrt(F) more or less. Radiocomm with submarines is done at very low frequency like 10kHz, with huge antennas from an aeroplane in the vicinity.

The effect works in the other direction too. If the atom is in a resonant cavity that favours the emission, the photon is emitted more quickly. Such lasers with one atom have been built too.

Obviously no-one can prove whether anybody else had the same idea within the same timeframe but didn't submit or publish it. The rules of patent offices hence base on evidence: who has described what at what time. To this rules, I'm the inventor because my evidence tell it, unless someone comes with better evidence. No snobbery nor narcissism in that, just the rule of the proof. Many people here would like inventions to be obvious, and similar ideas to be identical. This is not the case. Have a look at what patent offices accept as "new" idea: the changes are tiny. One example: At a symposium about micro and mini satellites, I described an aerodynamic fin for satellites on low Earth orbit, taking advantage of the very faint atmosphere. I even loudly supposed it was already done. A year later, a guy from the French space agency got a patent that tells "static aerodynamic fins for satellites are well known, but I have invented the tiltable aerodynamic fin for satellites and apply for a patent". The patent office granted him a patent. Having described the fin before (without telling it to be fixed), I found said invention to be thinny. While the decisions by patent offices are always discussable, they take into account that ideas are rare, and inventing anything is difficult. That's why, while robots are not new at a nulear power plant, and remote control neither, and a concrete pump had already been remote controlled, I do claim that remote-controlled cranes at Fukushima were a full invention, and so too was pouring water at Fukushima using a concrete pump. One example of innovation (not exactly an invention, but it illustrates how small progress always is): Electric cars had existed for over a century ("la jamais contente") and were in use. Lithium batteries existed for over a decade, including the very same chemistry. Elon Musk realized that an electric car with that lithium battery could have some useable range and imagined that some customers would be interested. He invested big money in it. As things happen, customers indeed want to buy the cars. Feel free to say "existed already" and "anyone could have done it". Fact is that other people didn't, or at least not properly. It is a significant innovation that relies on a tiiiiiny change. One other example is my contactless chipcard. Nikola Tesla had already tinkered around it, over a century ago. Contactless cards existed for decades, by radio and by induction, but without a battery the range was like 5mm. I put a resonant circuit and chose the proper operation frequency to obtain 10cm range (plus some datacomms). With that range, billions of RFID (or NFC) cards are in use. Previously, it was a tiny market. Again, feel free to say "existed already": yes, but not as I did it, and with the tiny change mine is better. And say "just a resonant circuit, anyone could have invented it" if you wish: fact is that the science and components were available for a century, but before me the other people did it worse despite the existing need. And I put 7 months of hard work to succeed with a resonant circuit at 13.56MHz (trying other very different solutions too). Inventors realize after few years how difficult innovation is and how tiny any progress is, and rarely say "it was obvious". Inventing is never obvious, quite the opposite. Only describing an existing invention may be obvious. And the inventions easiest to describe are often the most difficult to make.