Enthalpy

A propagating photon, with a real wave vector k, brings an electric field that moves. When the field is immobile, or in near-field, you can interpret it as a photon with an imaginary wave vector k. Adding the idea of photon to near or static electric fields isn't fertile. It's more a means to offer a homogen theory and vocabulary (photons, but then virtual) to a theory (electromagnetism) that works both for propagating and standing waves. Intellectually interesting. Whether the near-field is quantized... Someone proposed an experiment here, but failed to propose figures that support his claim, which look difficult from his qualitative description. Though, I feel the proposed experiment looks far better if changing radically some parameters, and I dearly wish he would come back with better explanations and experimental results - something we can make a scientific opinion about. At least when light couples from one guide to an other by evanescent wave, the idea of photon keeps some merit where the photon is virtual, that is, in the coupling medium.

I doubt that. No mass: maybe "hit" the detector is misleading. The photon bring an electric field that moves one or more electron. The effect on an electron is detected.

I suppose the person uses other muscles to control the ones inaccessible to nerve pulses. Like: electrodes detect the moves of the controlled muscles, other electrodes stimulate the ones disconnected from the brains.

This proposal isn't enough thought through. First, it distorts the advantages and drawbacks of each solution in order to misguide the reader. The advantages of reciprocal piston engine are: Seals less extraordinarily difficult (the Wankel works, among the many rotary piston designs, because seals have been invented for it, but they aren't easy). Combustion not always at the same place, which permits a high temperature and keeps cooling feasible. The advantage is not much the differential thermal expansion, rather the bare feasibility. This is the efficiency advantage over a gas turbine or a rotary engine. Combustion at constant volume instead of constant pressure. This gives a higher temperature for the same fuel amount and improves the efficiency. If one splits the compression and the combustion-expansion, be it at reciprocal pistons or a Wankel: The compression factor uses to collapse because of dead volume, and this alone collapses the efficiency. Combustion at a single place limits the allowable gas temperature hence the efficiency. Constant pressure is bad. Separate expansion permits a bigger expansion factor than the compression factor, which partly regains the disadvantage over combustion at constant volume, but a turbocharger does that better, combining the best of both. Reciprocating piston engines go already in this direction! They presently close the intake valve earlier in a controlled fashion so the compression factor is less than the expansion, at least at moderate power. I should like to remind that split engines have been proposed many times and have shown every time the same known drawbacks. I suggest to check the many thousand existing patents. Then, some claims are difficult to believe unless the proponents have excellent solutions ready. Air speed faster than flame speed, ouch! Only in an ideal world where detonation wouldn't exist. What when the walls are hot, the engine slow, and the driver requests torque? Air+fuel mix is the wrong choice and gives a bad impression of the designers. The obvious better method is to inject the fuel after the compression. Then, it can burn pretty much anything (gasoline, kerosene, Diesel oil, heavy Diesel, vegetable oil...): anything it is designer for, or at an existing engine, anything that fits the pump, the injectors, and if needed, the autoignition temperature. So a real progress would be to burn at constant volume and expand with a bigger ratio. Just one or the other is no significant progress, and the reciprocating pistons plus turbocharger is already a partial solution in this direction. Maybe a reciprocating or Wankel engine can have a second expansion stage, like steam piston engines had. More original attempts try to add closed combustion chambers at gas turbines. Difficult, but very interesting.

Those piezo disks rely on flexural modes, don't they? Then any adhering coating should show low losses, which would eliminate the liquids - they are bad as a chemical barrier anyway. I vote for the plastic bag not touching the piezo element. If the protection must be on the disk, then of a thin, hermetic and elastic material. Metals seem ruled out, alas, as the disks need electrodes, but a ceramic coating like SiO2 or Si3N4 offers an excellent protection. Its deposition needs a high temperature, fine for the piezo ceramics, but which restricts the electrode metals - small worry since the metals that protect against corrosion are the refractory ones. You usual semiconductor process engineer can tell that quickly.

Just a detail about superconductors: only the type I eject the flux. Unfortunately, their maximum current density is too small for most uses, which rely on type II superconductors. These have some losses and let the flux pass through. ---------- For your goal, the Laplace force isn't written with enough details as F = I B L because it's an interaction among vectors rather than scalars, and the result depends on vector directions. If B and I are uniform, L is straight, B and IL are perpendicular and you're interested in the F component perpendicular to both, then F = I B L is good enough and simpler. But for instance if B is parallel to the wire, you get zero F, which already tells that this is a vector computation. The proper expression is, where F, B and dL are vectors: F = integral ( B X idL ) where I write X the vector product of B and dL, and the integral is over the circuit. It's already a simplification where the circuit is thin; if not, we would integrate BXJdV everywhere, with J being the current density. In DC or at low frequencies, charge accumulation is negligible so the current I is uniform over the circuit. Then F = I * integral ( B X dL ). In this topic, you aim a uniform B if I understand properly. Then F = I * B X integral ( dL ) and without charge accumulation, the current flows only over a closed path where integral ( dL ) = 0 so F = 0. ---------- A nonzero F would appear when B varies along the circuit. With the geomagnetic field varying over huge distances, this effect on a small loop is tiny. But if you create the induction and change its direction from one loop side to the other, you get a force on a linear motor. Or a nonzero F can result from a non-uniform I, which implies high frequencies. Observed with radiation pressure. Or if you seek a torque, then the integral isn't B X dL anymore: you also multiply by the distance to the axis, and since the current can have one direction at one axis side and the reverse direction at the other side, motors rotate.

Low-voltage (understand 120V, 240V, 400V... up to 500V in this job) transformers have less and less turns as their core gets bigger with the power. At some point readily attained, the LV coil is indeed a single turn of copper sheet or plate (which doesn't mean "thin" in mechanical engineering) instead of wire, and to increase the power further, the transformer's shape departs from the optimum aspect to keep exceedingly sleek cores, but longer and spaced wider to give room to the windings. At 120Vrms (in star connection) and 60Hz, it takes peak 0.45Wb. Using the laminations at 1.7T peak, a single turn suffices with 0.26m2 core, or 0.51m*0.51m. That's a bit bigger than 1MVA, maybe 3MVA. It is a good reason to have ~1MVA MV/LV transformers. It's also said to be an optimum between transformer cost and LV wiring cost and losses. So even at usual 1MVA and 50Hz 240V, a MV/LV transformer has very few turns. As square wires would be impossible to bend, these transformers have sheet LV windings in a spiral. Excellent for the filling factor, but less for the eddy currents in the LV coil: flux leaking outside the iron core would cut all edges on its path around the currents hence flow through both windings near the core's edges, but the sheet LV winding prevents it (as it's thicker than 8.9mm skin depth at 50Hz) by flowing extra "eddy" currents that mean losses. An answer to this is to split the HV winding, half within the LV and half around, so that the A*t observed from the core outwards look like +- -+ instead of +-. I haven't seen interleaving exaggerated beyond splitting the HV, but this is done in switched mode power supplies where the LV winding is of sheet for the same reasons, though at lower power and higher frequency. No complete solution exists, because the sheet winding is much wider than the skin depth, and also thicker so it really prevents the variable flux pass through, by running currents as needed and especially near the sheet's edges. Though, as the A*t of the primary and secondary nearly cancel out, the losses are reduced by circulating the HV A*t as uniformly as possible, which most A*t in the sheets mimick. Ideally, only the difference of primary and secondary A*t, the magnetizing current, still induces eddy current in the sheets.

Found some data, but not at 1000°C up to now. Metals Handbook. Properties and selection : iron, steels and high performance alloys. Vol. 1, ASM International, 10th ed 1990. Depending on the C contents and the kind of cast iron, the heat conductivity drops like: 33 to 31W/m/K from 400K to 700K 39 to 37W/m/K from 400K to 700K 50 to 40W/m/K from 400K to 700K more carbon conducts heat better, I didn't expect that. Some more data, limited to 500°C more or less: nvlpubs.nist.gov/nistpubs/jres/12/jresv12n4p441_A2b.pdf Googlebook "ASM specialty handbook: cast irons" by Joseph R. Davis Depending on the needed accuracy, you could take a good fraction of the thermal conductivity of elemental iron for cast iron at real heat. At room and cryo the alloying elements change everything, but at 1000°C they influence less.

Such a core at 60Hz can't achieve 6kV reasonably. Imagine it has 15mm*15mm iron laminations saturating at 1,7T peak: the maximum voltage per turn is 0.1V rms. So even the 100 turns can't fit 120V, let alone 6kV. If connected to 120V without the current limiter, something will go bang, hopefully the fuse. This means also that for <100W power, transformers for 6kV or 20kV use a higher frequency as far as possible. Ignition at gasoline engines uses a sudden current drop, so did CRT television sets. If not, it needs many thousand turns, costly with a winding machine, impossible by hand. The parallel stray inductance doesn't drop at low current; it's independent of the current until a stronger current lets saturate the core. But this inductance is too small for the desired transformer. Imagine a relative permeability of 3000 at the 250mm long laminations: 1A*t induces then 15mT and 3,4µWb so the inductance per square turn is 3,4µH. Even 100 turns (let alone 2 turns) make only 34mH or j13ohm at 60Hz which is too little for proper operation at 120V - where in addition the core would saturate. So: You can't achieve 6kV with such means. Even 120V would be seriously tedious. A ring core is asking for uncomfort. Please keep off the mains as you clearly don't have the necessary knowledge.

Each prospector shall observe and sample many sites spanning a good distance, which takes months. Though, night lasts for 2 weeks on our Moon. The craft gets no heat, no photovoltaic electricity, and the ground cools down from 380K (Equator) or 220K (70°N) to 90K: http://diviner.ucla.edu/ but there is no blizzard, good news. The following figures on a prospector example explain how to spend the night without radioactive heaters. -------- Hibernation -------- The parts of the prospector fall in categories of thermal protection at varied locations. The temperature of these parts swings freely but a skirt protects them at night: - The uncooled niobium nozzle extension and the lower legs must live with sunlight, ground heat, flames and flying pebbles. - A metal sheet protects the cooled part of the engine and the attitude thrusters against flying pebbles, and the upper legs and the fuel tank against flames too. It insulates somewhat against ground heat. The oxygen tank is superinsulated and actively cooled. The arms and tools, eyes, Lunar samples are exposed to daylight but enclosed in pockets during the night. The battery and the electronics get a regulated temperature. The pockets also keep the arms, tools, samples boxes clean during the propulsion phases. The prospector walks away from the landing site, but the legs are still contaminated, and the propellants may leak a bit. If sampling the ground before the body passes isn't clean enough, then a different design must separate the walker from the flyer. To avoid nitrogen at the propellant, replace CCN( C)CCCN( C)CCN( C)CC with farnesane or phytane. In the evening, the prospector finds a smooth terrain, groups its legs, and lowers its skirt of multilayer insulation when the ground is comfortable. Many small masses press to the ground the skirt's last 0.5m, and optionally the arms put regolith there. 17m2 of 25 plies at 270K lose 2W, while 90kg ascent fuel store 150kJ/K and the ground helps, so this group cools by 15K. 3m2 of 25 plies multilayer insulation leak 0.6W in the oxygen tank, polymer belts 0.1W, pipes must insulate (polymer?), so the cryocooler consumes 5W at least and is shut off at night. 200kg ascent oxygen store 340kJ/K and warm by 3K overnight. The Osr cold sink is decoupled mechanically at night, it faces the sky and brings e=0.9 a=0.1 (one tool is a brush), so 4dm2 achieve 2*5W at 265K for the cryocooler. The 13kg Li-poly battery common with the engine provides 5W over a night, so every activity ceases but for a few sensors like seismometers. The prospector folds its arms and eyes in its pockets and closes them. The multilayered insulation is tapered at the joints. 23m2 of 25 plies around the batteries, equipment and pockets at 278K lose 3W, while twenty L=0.2m D=30mm tubes holding this part leak 0.8W as they consist of 2mm balsa and 2*300g/m2 fiberglass composite. The battery can increase easily if needed, the multiplayer insulation too, and alone the thermal inertia would suffice. The 0.5m2 equipment's Osr heat sink achieves 300K, regulation is by mechanical decoupling. Solar cells on several 0.6m2 faces provide 200W electricity and, if any needed, a warm source, otherwise they're insulated. If electric motors can't work in the legs, they can reside at the hips and operate all joints over tendons or shafts and gears. For instance, W=10mm e=50µm steel breaks at 1kN and 200K over 200mm leak only 43mW; titanium improves and composites more. The skirt eases many parts but isn't mandatory neither, if the fuel tank is with the equipment and the legs or hips of sandwich tubes. ---------- Robotics is a challenge at the prospectors, which aren't in permanent contact at the Moon's far side. Beyond walking semi-autonomously, they should gather a list of small unbroken samples alone and pack the man-chosen ones, change the tools at their arms and clean the solar panels, cold sinks, samples containers, clean away or sample the regolith, conduct a list of laser chemical analyses... I've taken 1000kg starting from orbit as a basis for scaling, but the unfolded prospectors would be 2.5m huge then, so over a dozen smaller prospectors are possible and desired to sample more sites, and they should move quickly to explore varied terrains. Prospectors autonomy is a key to relieve the operations team. Marc Schaefer, aka Enthalpy

If using rotating disks to evaporate a solvent and concentrate a solution, a method that looks less prone to clogging, one may prefer to condense the solvent afterwards or catch the odours. On the appended sketch, a second set of rotating disks interleaved with the first set shall do that. It brings a second liquid to close distance to the first one over a big area where the vapour of the first liquid condense. The second liquid can be cold to favour the condensation. It can be of the same nature of the first solvent. The second liquid can also catch the first solvent's vapour by a strong interaction. Hygroscopic substances are known to absorb water vapour for instance. One hygroscopic substance is ammonia solution, whose vapour might (or not?) impede the transfomation of urea into poisons if heat is used. Both liquids can move slowly through the machine, for instance parallel to the rotation axes here, preferably in opposite directions so the second liquid enters the machine fresh at the end where the first liquid exits concentrated. A good casing lets choose the operating pressure. The disk profile can have a groove at mid-thickness if this avoids drops falling in the other liquid. Marc Schaefer, aka Enthalpy

I have nothing against the possibility of building a DC transformer this way, especially if the ripples are addressed. I have much against its usefulness whatever the power. Three decades ago, power electronics was already the best choice at Itaipú to convert 12GW between three-phase, the DC transport line, and three-phase back. Lenz' law applies here too but with caution... It doesn't differ much from a DC generator by the way. That is, the induced current opposes directly the cause when the self-inductance limits the current in the induced circuit. When the resistance limits the current, this current is in phase with the inducing voltage instead of lagging 90°. In intermediate cases, the phase between the inductor field and the induced current is somewhere in between and the effect of the induced current adds vectorially. At a rotor where the mechanical angle evolves over time, a phase lag in a current or voltage that offsets them in time also changes their mechanical angle as seen by an observer on the rotor. As a consequence, the induced current has a variable angle with the inducing field, and so does the field it creates. Take a DC generator for instance, with just two horizontal poles and a vertical axis as on your drawing. The inductor field creates the maximum voltage (or better EMF) in the loop parallel to the drawing plane at a given time. If the loop is essentially inductive, the current changes most at that time, and is maximum when it doesn't change: when the loop is perpendicular to the drawing plane. The induced current creates a field that fully opposes the inducing field. But if the loop is essentially resistive, the induced current is maximum when the EMF is maximum: when the loop is parallel to the drawing plane. The induced current creates a field perpendicular to the inducing field, which doesn't oppose directly. The effect is much smaller. In a big DC machine (already at MW), the induced current (or more generally the rotor current as it's the same story in a motor) can be stronger than the inductor current and would create a strong field. This is avoided by a special winding at the stator that is mechanically offset by 90° from the inductor winding and through which the rotor current is passed too. Even at smaller power, this is important to reduce the voltage among the loops switched by the commutator and let the commutator live longer. The same effect happens in three-phase machines, but no special winding is added there because the three or more windings suffice to create the field in any direction and with any phase lag - including to compensate the field created by the induced current. One consequence is that the mechanical angles between the fields, voltages and currents change at the stator and rotor - nothing to see at the physical components. Though, it still does need more current and lost power, and it also implies that the lagging consumed current is the main limit of a three-phase generator. It also applies to squirrel-cage motors. The rotor must be resistive so you get a torque. If the rotor gets too inductive, for instance because the induced frequency rises with the slip speed, then the induced current still increases with the EMF but it creates a field parallel to the inductor field and less torque. Starting rheostats, double rotor windings, and now electronics, are all meant to address this weakness of a smaller torque at low speed. One funny case appeared as I developed the contactless chipcard (RFID, NFC). I put a resonant LC circuit on the card and noticed that the induction in the reader's field increased much when I brought the card close. It puzzled me as I had expect the consequence to reduce the cause. My explanation is that the induced current creates a field at nearly 90° phase lag with the inductor field, hence capable of exceeding it without compensating it. Back to your example: you've drawn a resistive load, so the rotor current creates a field that combines at 90° with the inductor (stator) field, so it doesn't oppose directly, nor does it change the EMF much, neither at the primary nor at the secondary winding.

Hi Soderdahl, nice to see you again! You can take the heat capacity of pure iron for its alloys containing a few % other elements. A polynom here http://webbook.nist.gov/cgi/cbook.cgi?ID=C7439896&Mask=2 A monography there http://www.nist.gov/data/PDFfiles/jpcrd298.pdf For accuracy, distinguish between alpha and gamma iron and the transitions between them. The heat conductivity differs a lot between pure elements and their alloys. I'll check if I have data.

Some press papers claim an oxygen and methane engine is under development that uses a full-flow staged combustion cycle as in http://www.scienceforums.net/topic/81051-staged-combustion-rocket-engines/ and while this has been done for axygen and methane, and may perhaps work with a handful of amines http://www.scienceforums.net/topic/83156-exotic-pumping-cycles-for-rocket-engines/?p=805383 also there and following messages http://www.scienceforums.net/topic/82965-gas-generator-cycle-for-rocket-engines-variants/ I believe soots prevents methane in a fuel-rich pre-chamber. A more exotic cycle would make sense, where methane follows an expansion cycle, oxygen a staged combustion, and each pumps itself: I plan to consider coupled shafts later. Here uncoupled: Besides hydrogen, only methane fits. Ethane, propane, cyclopropane, spiropentane... stay liquid around 300K and a few 10bar. Hard-to-light fuels are excluded. Each turbine drives a pump for the same propellant. Leaks are less critical, seals are easier. Each turbopump is smaller. Not needing to pump the oxygen, the methane expansion cycle achieves a decent chamber pressure. As the methane side limits the chamber pressure, the oxygen turbine is cooler than in a usual oxygen-rich staged combustion. Two cycles must be started at the same time. The methane engine developed by SpaceX uses probably this cycle, without coupling. "Lower turbine temperature", "easier seals", "both propellants gaseous", "no soot" - and misleading "full-flow staged combustion". The hybrid cycle brings technological advantages, but how efficient is it? This depends much on arbitrary choices. 800K=527°C out of the cooling jacket, already a lot. Flowing down protects the chamber better than up. A strong engine needs several long chambers. This holds when the engine throttles to 60% thrust, so at 100%, methane exits the jacket at 515K. P/2 expansion to the turbine is best, the isentropic work to 455K is 2760J/mol. A turbine 79% efficient, pump 74%, injector 88%, and no loss elsewhere (which is unfair) leave 187bar in the chamber. Taking the usual oxygen-rich staged combustion Rd-170 as a reference, which obtains 3307m/s gas speed from Rg-1 "kerosene" at 535bar/245bar/0.8bar: Bulkier methane in a fair extrapolation of this cycle would burn at 228bar and gain 8s, Pmdeta 3s, cyclopropane 10s. The present hybrid cycle at 187bar gains 4s only. Does some decent amine mix work in a recombination prechamber? This full-flow cycle does bring performance and the same advantages. Some improvement paths: Shutting some chambers off to throttle would gain much. Or heat the methane by an exchanger at the preburner mainly. Heavy, but the main chambers are fewer and shorter, and a staged injection can regulate the methane temperature when throttling. Cyclopropane then? Couple the shafts. While the hybrid methane cycle eases the turbopump seals, it gains only 1s over Pmdeta. I'd prefer the hard-to-light fuel. Marc Schaefer, aka Enthalpy

Cooling jackets waste pressure from the propellant flowing through. How much is unclear: seemingly 20% at the RL10-B2, losing 2s specific impulse, at the Vinci possibly more. The azimutal flow direction is short and broad, as opposed to the axial one, that's how I want to save propellant pressure, and several inlets and outlets in 360° would improve further. Though, the fluid layer near the surface must be replenished quickly for good heat transfer, and a slower fluid may need help for that, for instance by successive jumps that achieve a vortex pair in each channel. ---------- Ariane 6 could use an eight-chamber Vinci at the main stage, with a common set of turbopumps and actuators, and D=1.3m nozzles on a circle in the D=5.4m body. This matches Vulcain's thrust (8*171kN vs 1359kN), gains 14s (Isp=443s vs 429s) and hopefully dry mass, especially if the uncooled nozzle section is of niobium instead of SiC - and must be cheaper. The D=1.3m nozzles expand to 0.07bar hence can't start at ground level. The P120 push enough for Ariane 62 and 64, and the Vinci can start in flight. A hypothetical Ariane 60 would stop the nozzles at the cooled D=0.7m section, where the expansion to 0.34bar can be stable in the air and provides Isp = 4025m/s = 411s and 8*159kN in vacuum, and at sea level Isp = 3037m/s = 310s and 8*120kN. Inducing voluntarily a clean flow separation, for instance with the means I describe there http://saposjoint.net/Forum/viewtopic.php?f=66&t=2411 would enable the D=1.3m nozzles and improve the sea-level performance to Isp = 3270m/s = 334s and 8*129kN to lift-off 88t, enough to put 7t in Leo. Ariane 6 has four places for strap-on solids (to reuse the Ariane 4 launch pad?) but these could be liquids too http://www.scienceforums.net/topic/65217-rocket-boosters-sail-back/#entry915939 or combinations with smaller solids to fine-tune the performance. For instance the Zefiro 23 works at sea level, its stronger successor supposedly too. Marc Schaefer, aka Enthalpy

But was that the original question? Several billion years is the mean time it takes for nuclei to have a chance to come to the conditions permitting the fusion. Once they're at the proper distance, the beta decay and other operations must be snappy. Everything has to be quick, faster than the protons need to come apart if the fusion doesn't proceed.

Like the other answers, I have nothing against producing work with that wheel. It just needs some means to remove the humidity from the hygroscopic substance when at the bottom of the path. This removal takes some form of energy, for instance heat, in which case the operation would be an engine.

Welcome, IshanAmin! I don't see where your report is.

The dioxide emissions favour the use of propane because if you don't use it, it gets torched at the production well. The efficient use of propane needs an adequate engine.

Danijel Gorupec's question were absolutely sensible and important. BiotechFusion, if you can't give consideration to suggestions when they don't fit your way of thinking, you won't be able to progess neither. Being kind with other people would also be a requisite to get help. Good luck!

I see. Good luck then.

Service pack 1 for the wound graphite stage over a P120. Balsa doesn't insulate the tank heads so foam must do it, 10mm thick or less at oxygen (+16kg) and 15mm at hydrogen (+24kg). The core between the tanks must be removed once the cylinder is wound. It can be molten, taken down... but a hole is necessary. I imagine the graphite fibres can by-pass the hole(s) when they're laid down and get a local reinforcement. Ask the experts. I addressed only the azimutal contraction of the skins at cold. The axial one creates in the core a shear stress that decreases exponentially from the temperature transition over a distance (e*s*E/G)1/2 (thicknesses and moduli) and is small, about 300kPa if G=1GPa.

Ahum. Maybe I can make a better answer than a single word. The potential field results from some interaction with the electron, which is often an electric potential because an electron is most sensitive to it due to its charge, and is in most cases the electric potential from nuclei and other electrons. But for simplicity, said potential is often modelled as an energy of undefined nature, with some distribution over space - like a tub for a quantum well, a ring for a benzene molecule. Then the equation for the electron gives a set of solutions where the rest mass and the kinetic energy don't necessarily appear as such, depending on how you decide to write them. Among these solutions, some depend on the time only by exp(j2pi*Et/h). Their amplitude is constant over time. They're called "stationary", and are indeed immobile, static, motionless and so on - except that the electron can have a kinetic energy, a momentum, an angular momentum. So ol' Schrödinger's equation not only describes the movements of electrons, but also immobile electrons. Stationary solutions are useful because where the electron is confined in one or few atoms, the energies associated with the varied stationary solutions are well separated, especially as compared with kT at room temperature, and then the usual case is that the electrons in the well fill the modes of lowest energy and leave the others unused, with certainty. As well, we know that when an electron is trapped, all the possible wavefunctions are linear combinations of the stationary solutions. And here we see moving wavefunctions, that do evolve over time, just as combinations of immobile solutions. Take a 1-D nanowire as an example. The first stationary solution is a half-wave (with certain boundary conditions) and the second a full wave over the length, with a phase exp(j2pi*E1t/h) and exp(j2pi*E2t/h). When the wave is a superposition of both, like 1/sqrt(2) of each, say during the emission or absorption of a photon, the superposition reinforces the wave at one half of the nanowire at some times and weakens the other, and at other times it reinforces the other half. This results from both waves of the superposition being in phase or in opposition. The phase condition evolves with time because both phases rotate, with frequencies E1/h and E2/h. A reinforcing superposition at one nanowire half happens again with a frequency of (E1-E2)/h. As the resulting wave isn't stationary, the electron has a movement, in this case from one nanowire half to the other, with that frequency (E1-E2)/h, at which it also emits or absorbs light because of the accelerating charge. And now we see the mass appear, because E1 and E2 depend on it through E=(hk/2pi)2/(2m) where the nanowire length sets possible values of k, and so does (E1-E2)/h, the frequency of the electron's movement.

Welcome, holdensteady! The cheapest way is to burn the tyres. The thick black smoke is carbon in small particles. Partly because tyres are produced with a load of carbon black, and partly because the combustion makes soot. You know that carbon black is widely available and cheap?

Hi Donci6552, electrolysis is tricky and it's hard to predict and even to explain afterwards. Even if you had anodized the metal properly, the layer's colour depends on details of the alloy. "Magnesium" is probably a magnesium alloy. For instance pure Al makes a brilliant oxide layer but Al-Zn alloys a grey one. Apparently, Mg can be anodized in aqueous electrolytes. But is a bicarbonate the best choice?