Enthalpy

"In the frame of actual science, no possible explanation can be..." now that's an ambitious statement. I have nothing against an electric current, resulting from the different redox potentials, that lets zinc dissolve faster and iron slower.

Fun: I had the same desire as a teen (though not for weapons). The material with lowest loss (unless some miracle happened unnoticed) is silica used for fiber optics. Significant attenuation occurs over some 100km, so at 2*108m/s propagation speed, it stores light for 0.5ms. Smaller loss is possible in vacuum, provided light stays bundled, vacuum is maintained by a tube over the whole path, and excellent dichroic mirrors reflect it at the ends. This is done a gravitational waves detectors: http://en.wikipedia.org/wiki/Gravitational_wave_detector Ligo lets light bounce 75 times in the 4km long arms, but how much light is lost is unclear: http://en.wikipedia.org/wiki/LIGO simplistic signal-to-noise computations would tell "lose exp(1) is desireable" so this would mean the photon survived 1ms. Then, you might put a mirror on the Moon, an other on Earth (let's forget nasty technological limits), and 2*75 bounces would retard by 3 min. Though, it needs of course to suppress the atmosphere, and takes big mirrors: at 0.5µm wavelength, 100m diameter and perfect polish would let light diverge by 2m after one leg, almost good enough for 2*150 bounces.

An emitter in a cavity is a laser. A gain medium is nothing more than an emitter, even a single excited atom. The very limit to make a laser from any emitter is that the de-excitation time is longer than the cavity travel time. The cavity folds the wave. This is aboslutely necessary to make a laser, and even to make a void resonator. One may define the size of a photon in many ways, as usual with a particle. Once you detect the photon with an atom, you may tell that the photon was the size of this atom, but prior to this, the reasonable definition to me is the extension of the wave packet, which relates directly with the linewidth and the lifetime of the emitting transition. I feel we're back to a previous interrogation: to me, a long-lasting atomic transition does mean that the emitted photon is that long - and not that the short photon has a probability to be emitted over a long time. Only when the photon is detected, or the atom observed, can we tell the position of the photon. I understand as an argument in favour, that emission linewidths are routinely computed by opticians from transition lifetimes. A photon shorter than the transition lifetime would have a broader spectrum.

And the coefficient of friction differs radically from the shear-to-yield strength ratio, which tells that the plastic theory does not work at all. Presently there are half a dozen theories often cited, none works. Theoreticians try to mix all these ad explanations and, with enough tuning coefficients, claim to match one observation under one set of conditions. Mechanical designers refer to experimental values and keep in mind that these are not reliable nor reproducible. We lack a working theory. But the one with contact angles (was it from Newton?) is not the solution.

You have to decide whether heat is to be radiated by the material or brought to the users by blown air. In the first case you need a refractory, in the second case a melting paraffin brings excellent capacity (but may burn with a wick). The second factor of choice is material cost. Just a block of aluminium for instance is probably too expensive for a heater. This usually drives the choice to non-technical ceramics.

No absolute electric potential exists, so "the potential" should better be avoided. You may encounter the expression when the reference potential is at infinite distance, but I'd strongly prefer books and professors to formulate it more clearly, as this is a difficulty in understanding electromagnetism. http://en.wikipedia.org/wiki/Electromotive_force "For a time-varying magnetic flux impinging a loop, the electric potential scalar field is not defined due to circulating electric vector field, but nevertheless an emf does work that can be measured as a virtual electric potential around that loop."

Falcon 9 v1.1 has flown, congratulations! An additional stage would enable missions of higher energy, where O2+Rp-1 and electric pumps bring performance. Similar engines can be roll and injection Verniers at the second stage. A quasi-Hohman travel to Jupiter from a Geosynchronous Transfer Orbit (Gto) takes 3850m/s in a single kick, which imposes 13943kg propellant capacity and 32kN thrust for the Heavy launcher. Relaxing this case would permit a fainter, more efficient engine. Performance estimates adjust the tanks filling (this is suboptimum) to start with 13150kg at 200km 28.5° Low-Earth-Orbit (Leo) or, for the Heavy launcher, with 21280kg at 28° Gto. Four 1m nozzles expanding from 60 bar to 289Pa achieve isp=392s=3846m/s. 70% efficient pumps take 58kW and 25kW at the shafts to achieve 68.2 bar. Lithium-polymer bring 475kJ/kg and weigh 20.8kg/t of propellants, up to 290kg at full tank capacity. The truss shall break at 6MN*m. Made of AA7022 tube, it weighs some 350kg. The skin is dropped early, as in http://www.scienceforums.net/topic/60359-extruded-rocket-structure/page-3#entry764231 15mm foam isolate the oxygen for 30min in air, and 8kg multilayer insulation for 80 days in vacuum: can be more. 200µm steel contain the oxygen, 50µm the Rp-1, polymer belts hold the tanks to the truss. The tanks weigh 76kg. The pumped engine shall weigh 150kg, the sensors+transmissions+controls 200kg, four half separation belts 80kg, unaccounted 100kg. Empty mass is 956kg plus up to 290kg battery, or 89kg/t of propellants. Marc Schaefer, aka Enthalpy

If the mirrors are closer to an other than the size of the photon, then you have made a laser. This is exactly why laser designers want a long de-excitation time for the lasing transition. A too quick natural transition means spontaneous emission too often, no lasing. A laser is also known (including experimentally) to work with a single photon. This means that the usual explanation of the laser, where one photon stimulates the emission of a sibling, is a bit short. From my electronics background, I prefer to imagine that electrons have a too stiff position in atoms, giving them a high impedance that maches vacuum badly, so that coupling is inefficient and the transitions takes long. In a cavity, resonance increases the impedance seen by the electron (at some places - I've suggested to put the lasing atoms only there for efficiency) and improves the coupling, so that emission is faster. In a Yag, this time can drop from ns fo fs. More photons add their field in the cavity, which also increases the coupling with the atoms. This explains why lasing centers synchronize with an other. By "size" of the photon, I understand the length (and width if useful) of the wave packet. This has very practical implications: these "coherence time" and "coherence length" limit the path difference over which one can get interferences.

Said theory was proposed several centuries ago and is known to be irremediably wrong. Contradicted by experiments, both quantitatively and qualitatively. Anyway, a solid is deformable, and a surface isn't flat.

It's called gravity gradient and is taken into account in the design of any satellite. Gravity gradiometers do it all the day in submarines. They are used for navigation.

With really a single photon, the wave function cannot be measured, I believe. You detect the photon once, it happened to be here, or there, or there. Some experiments tell "single photon" but use many of them, so that the number of photons detected around each position permits to reconstruct a wavefunction. It's rather "one photon at a time", which just needs faint light intensity, but is conceptually difficult, because we use to ignore when the photon was emitted. Most often, we just know at what mean rhythm photons are detected.

I'm pleased with that explanation. Two different time scales here. The transition energy defines the photon's period, frequency, wavelength. The duration of the transition defines the frequency breadth, wavelength width, and stretch of the photon over time and distance.

Just a sub-sub-detail: integers are often slower than doubles or floats. It's often the case for multiplication - just because Cpu designers don't pay much attention to integers - and always for division, because integer division uses an exact algorithm which take about one cycle per bit (or slightly less now) while double division and sqrt are approximate and iterative algorithms that double the accurate bits at each iteration. Presently, Cpu take one cycle per multiply or add on doubles (or even on double pairs, some Cpu on double quadruplets) while an int multiply can need several cycles. And did I read that since the Core2, integer computations are made by the Sse hardware? Though, if building hardware purposely, integers do save gate counts and may be faster, sure. Sorry for interrupting, I understand operation speed is not a part of the algorithm's intrinsic speed. Any improvement on such a well-known (...and useless!) problem would be remarquable.

That's enough to state that you don't know Relativity. You shouldn't try to explain it to other people. By the way, not telling for which observer mass, length, time are changed does not permit sound statements. And under "Are you sure?" you could have understood "you're wrong" and stopped timely. In your own theory, or your own understanding, maybe. But in Relativity yes. Mine as well. In daily life, and almost always in engineering and physics, it is more convenient to offset all accelerations by 1g - so much that our intuitive perception includes the offset. Could that be a reason? Also, the Euclidean space (-time) is very convenient and fits our normal life experience, so that adding a gravity force separate from acceleration is a small cost to keep a big simplicity. After all, the best specialists for GR can completely compute just very few situations: the Universe, a black hole, and very little more. The rest are corrections applied to classical mechanics when relativistic effects are small. Why should normal people in their daily life prefer a mental image that specialists can't use?

Really really sure?

None. With presently extrapolable technology, we have no method at all. The best feasible method I see (though not desireable!) is to cover a thin film with a superthin alpha emitter to catch the recoil. But it's incapable to send anything to the nearest star within, say, one full human life. It would need to carry an energy source more concentrated than radioactivity, fission, fusion - something like antimatter. Or to find energy in situ or bring it there - how?

Did you play with matchsticks once again? Here comes the fire brigade, with tools of adequate size. Many aeroplanes, especially military cargo planes, have desirable performance as a water bomber: sturdy, good capacity, good climb rate, reasonable flight speed... The Bombardier 415 adds the precious ability to refill its tanks by scooping water from sea or a lake: http://en.wikipedia.org/wiki/CL-415 and I should like to explain how more usual airframes can obtain this ability. The plane flies a few metres above water and lowers a boom that scoops water to the tank(s). The boom is articulated at the airframe. Downlift comes primarily from the steering winglets. Its design is inspired by a refueling boom. A lightweight ski(s) follows the water's height. The winglet-ski combination shall alleviate shocks at the airframe by the waves. Elasticity can be built in between the winglets and the ski. Design anyway this place as the weakest mechanically. The opening of the scoop can be lower than the ski. The scoop - or its opening - is smaller than depicted. Its drag is smaller than the touchdown of a waterboat. Two-axis articulation of the boom may be better when the wind doesn't align with a small lake. Alternately, the lower tip of the boom can be well profiled to plunge deeper into the water without a ski. This may be better at rough sea. The spherical tank is to give a visual impression of the volume that the aeroplane used in the illustration can lift. Putting it (or them) outside the fuselage, like before the wheels, over the wheels or under the wing is probably better, as flushing it quickly is very important, but shouldn't destabilize the plane. Water flowing in quickly is dangerous. It needs jet breakers at the tank, and protections for the personnel. I'd let it spill over when the tank is full and provide it a wide way out of the airframe. Yes, you can take a bigger aeroplane, of course. Maybe a C-130 Hercules. But to use smaller lakes, preferably a not too fast aeroplane. Or design one purposely. A remote control would be nice as well. Marc Schaefer, aka Enthalpy ==================================================================== Only the Canadair-Bombardier CL-215 (and CL-415 with turboprop) were built purposely. Scooping procedure is summarized by pilots: http://bernard.dumas.perso.infonie.fr/Ecopage.htm http://pelican.46.free.fr/Caracteristiques/body_caracteristiques.html Splashdown at 75kts, give power once arrived at 60kts, then open the scoops to take 500kg/s water. End scooping, accelerate up to take-off at 78kts, accelerate further to 96kts then climb. Scooping takes much propulsive force, but less so in a seaplane moving slower than its stalling speed. The CL-215 flies rather slowly, as a further design advantage, enjoying a big propulsive force. In contrast, the Casa CN-235 flies faster, and would scoop in flight, hence above its stalling speed, or around 50m/s (100kts). Many cargo planes are a bit less favourable: faster, and their flatter ascent angle meaning less available propulsion force. Commuter airliners fit even less because they're faster and not as sturdy. As a seaplane, the CL-215 touches down and takes off parallel to the swell, not against the wind direction. A cargo plane must scoop parallel to the swell also. Then, at 50m/s and 10% from parallel direction, with 3m swell period (at the Mediterranean), the advantageous ski oscillates with 0.6s period and can be kept. I estimate the Casa CN-235 has over 10kN excess propulsive force available, from its 9.0m/s climb rate and 10.1t empty mass. This allows only to scoop 200kg/s at 50m/s, needing 30s and 1.5km to load 6000kg, instead of 0.3km. Irrelevant at sea, but a drawback on a lake - the penalty for a mass-produced aeroplane. Forces at the boom and the airframe are nearly simple... I take a slope of 1:2 for the boom. 200kg/s water turning from -50m/s to +50m/s create 20kN drag and 5kN down at the rear of the boom. The airframe pulls the articulated front end of the boom with zero N*m, (nearly) 20kN forward and 10kN up, but water impinging at the tank pulls the airframe 10kN forward and 5kN up. As a sum, the airframe feels 10kN drag and 5kN down. The rear end of the boom is pulled up (by the plane minus the water) with 5kN, to be compensated by >3m2 airfoil. At least one nice aspect: if the boom articulates at the right height (suppress the door), the airframe won't feel a pitch moment. Airborne scooping procedure could then be: stabilize at 50m/s and 5m, lower the boom, press the ski down with the airfoil, give power, then open the scoop. The airframe feels immediately 5kN (0.5t) down force, which would lower it by 0.5m after 1.4s, but is to be compensated. Water flowing in makes the plane heavier by 0.2t/s, to be compensated. Then close the scoop, raise the boom, accelerate and climb away, you guessed. The operation pulls toward water an airframe not designed for sea and this is more risky than with the CL-215. On the other hand, the cargo plane doesn't have to splash down, a risky operation avoided. I want that the pilot has a fast (typically pyrotechnic) emergency button to sever the boom from the airframe, in addition to the fast release of water. When scooping (and when dropping water as well) it would be better to control the plane by its landing flaps instead of its elevator. Build faster actuators there if needed. A pair of rods between the wheel fastenings, the water tank(s) and a point about 1/3 out at the wing would improve strength. Keeping the cabin pressure constant, even near sea level, would be nice to the crew. And improve all protections against corrosion... Marc Schaefer, aka Enthalpy ==================================================================== For safe operation, the ski should drag very little when not scooping. This must prohibit a scoop built deep below the ski, changed my mind. The ski may have a portion of its width reaching slowly deeper, where the scoop gets steadily water, as the best possible design. I like the latest design of the retractable scoop at Canadair's CL-415. It's a sector of a cylinder that plunges into water by rotating around its horizontal axis. Fits the ski nicely. The plane will not scoop into the wind but parallel to the swell, flying hence sideways, so the boom must move on two axis. I'd place the emergency button that severs the ski or the boom from the airframe just like the trigger button on a combat plane: at the yoke, with a latch. ==================================================================== The current fleet of water bombers is ageing: the original CL-215 was designed five decades ago, and existing planes show fatigue, the Canadair as well as modified airframes. Several airplane manufacturers think at a follower (including ultralight aircrafts, which may explain why I saw so many fly over as I was thinking at the design), and I just have to add my own frenzy to the existing mess. Among the older CL-215, Spain has lost 7 from 30 acquired, France 4 from 16. Among the CL-415, 7 have been lost from 60 built. Breaks in flight seem to be the main cause of accident, due to low flight over difficult terrain, and turbulence by wind and fire. Unspecialized airplanes use to be less solid; the C130 Hercules as a water bomber has been abandoned in Europe after two of them broke. So I consider a specialized design should have such qualities: It must be controlled remotely. The pilot stays on the ground, possibly aided by a scooper-dropper shared among several planes. The airframe must be solid and resilient against stalling. It should better be slow and drop its water well above the stalling speed. Climb rate is important, finesse far less. Carrying capability doesn't need room, as water is dense. And this is how I imagine the design: A biplane. Out-fashioned, but still naturally solid with cross struts. With more area, it lifts more weight at lower speed. The landing flaps control the pitch (though the elevator must be controllable). The water tank(s) can act as an emergency water rocket to lift the plane. A single turboprop. But I'd add a parachute, as some ultralight planes have, to land the whole airframe not too hard. Of course, scoop in flight as described above, without needing a sea plane. Though experience shall tell if it's better. The landing flaps, with fast actuators, act more rapidly on the flight than the elevator does. This is useful near the water, the terrain, or if stalling. Accordingly, the elevator is at the rear. With its wings more closely stacked than usual, and especially if the upper one is a bit before the lower, a biplane keeps more lift when stalling. When using an added tank of emergency gas to put the main tanks at 30b, flushing 10t of water lifts (and pushes forward if desired) a 10+10t aeroplane during 4s, enough to recover from stalling. Use many small nozzles. The parachute is fastened to many parts of the aeroplane, in case the frame breaks. It's probably better to let the plane decide alone if using stall recovery processes or the parachute, since the pilot has only visual information. The remote control must be tamper-proof, and the plane may take over if remote control is lost. The water tank(s) must be vertical and narrow to reduce the longitudinal movements of weight. Marc Schaefer, aka Enthalpy ==================================================================== Pictures of a biplane water bomber! Something like 10t water in the size of a CN-235 but flying slower - or scale up and down. Fowler landing flaps would probably operate too slowly. A compromise would be simple flaps put permanently lower than the wing's trailing edge, as the Fieseler Storch had, but this increases drag. Neither the size of the elevator nor the scheme to retract the main landing gear (to the front here) have been checked. Marc Schaefer, aka Enthalpy ==================================================================== This water bomber shall fly continuous 16h thanks to hydrogen, so it can operate far from its base and saves ground time. A vacuum-insulated tank stores 360kg liquid hydrogen, as I describe there http://www.scienceforums.net/topic/73798-quick-electric-machines/#entry738806 enough for 12 fuels cells of Honda's FCX Clarity type (each 100kWe and 100kg, 60%) at mean 900kWe. Full 11750kg include 6250kg water, 1200kg fuel cells, 700kg hydrogen and tank. With L/D=12 at 35m/s and 70% propeller efficiency, the plane climbs 4.4m/s or scoops with its ski. With L/d=15 at 60m/s and 75%, cruise takes 620kW. Eight tanks limit water movements. Pairs of opposite tanks share pressure-gas and drop valves. Tanks in the wings would ease the pitch balance, worsen the roll a bit, but would be difficult to empty in 2s. Tandem wings would accept more pitch torque but have regular strength. Hydrogen mass creates a small torque. Put the fuel cells to adjust the center of mass. The biplane strengthens this water bomber and packs 150m2 in little room (though looking like an old monster) while making stall less brutal. Tip walls are not sketched but bring much to biplanes. Four 2.4m propellers look easier than two 4m pieces, and electric motors are simpler than turbines anyway; they blow only the upper wing, so the lower wing should be more offset to the aft than sketched. Again, mainly the flaps control height and pitch, for swift reactions near the terrain and the sea. The nose gear could retract near the fuel cells, and the main gear in the Kármán or behind the water. Several remote-control crews should share the 16h; one scooper-dropper can operate several aircrafts. Previous considerations about automatic anti-stall manoeuvres, lift and acceleration by water jet... still apply. Infrared and radar imagery would widen the operation conditions, if desired to nighttime; bigger tanks would easily bring the continuous operation to over 48h. Marc Schaefer, aka Enthalpy

Are you sure?

NO. Your maths are way off. 0.01c is unattainable with isp=6000s, and is unrealistic with Vasimr because the energy source isn't concentrated enough. 120,000s refers to the ejected mass, but the required energy comes from a heavy fuel and reactor - this isp figure is just dishonest from its promoters and you got fooled by it. Vasimr cannot move a big payload. Even if it had 100MWe available, at isp=120,000s and 100% energy efficiency it would provide only 170N. The cold sink at 500K for 100MWth (if the thermal conversion were 50% efficient from a hot temperature) would need 28,000m2. If this cold sink is material and weighs 1kg/m2, it adds 28t. A 50t ship accelerating at 6mm2/s would take 16 years to attain 0.01c, but 1GWe nuclear reactors weighing thousands of tonnes must be refilled yearly - impossible in deep space. Then, the nearest star is still 5 centuries away. Even if the payload is smaller, the mass of the reactor and the fuel scales with the thrust, keeping such speeds impossible. Oh, and just in case, I should like to remind that fusion reactors don't work. Vasimr may be good to hop within the Solar system with careful trajectory planning. It should be excellent to put satellites in geostationary orbit. But it's incapable of joining the next star. Because, again, it does not exist. Nor is it even feasible. You're mixing what has been vaguely imagined, what is possible, and what exists. Science-fiction is not science.

Are you sure? Gravitational waves are presently described as transverse quadripolar waves. Shall they have an axial effect? Through the axial gradient of a circularly polarized wave acting on a rotating, transversally elongated mass? That would multiply again by zero dot nothing. Up to now, no single one has been observed despite the unimaginable sensitivity of the detectors. Shall they bring matter to light-years? Human technology doesn't produce gravitational waves, even at the strength that we could detect. So if you know a means, just tell! The Orion drive is science-fiction, not technology. It cannot achieve 50% c (even if it were working) because nuclear energy isn't that much concentrated.

Much simulation work has been and is done on this topic and related ones (not by FEA). Though, astronomer now know that these simulations don't work properly, because they predicted instability (for planets around a binary star for instance) but the configurations have been observed. Looks like the algorithm was unstable, not the celestial configuration. So the present situation is rather: we ignore it. For instance Jupiter and Saturn have many moons. Some moons are in resonance, others are not and don't get ejected neither. This is a hint that many planets may orbit smoothly a star.

Non-nuclear weapons exist to produce EMP and have been used, for instance against Al Jazzera's transmitter in Bagdad. Several methods exist. Sakharov invented the older one, where explosives compress a magnetic flux. http://en.wikipedia.org/wiki/Explosively_pumped_flux_compression_generator It fits in a (possibly winged) bomb. More recently, semiconductor switches (and I suppose driven sparks before) enable a simpler discharge in an antenna. France and Germany cooperated on its development, but the US are often ahead in weapons, and I suspect this one already existed. They fit in a hand luggage. I'm convinced, from the observed effects, that one was used in Aoste and in one more southern city of Italy. The threat is already old and very well known. Over 20 years ago, all military equipment was required to resist EMP weapons. The requirements are often disguised as "lightning"; protection implies metal housing (easy) with perfect seals (uneasy), EM-tight ventilation (uneasy), surge arresters at all cables (difficult at weak or fast signals). Because these weapons exists, work, leave little clues, they are used, and are weapons of choice for secret services. I strongly advocate that airliners be protected against EMP weapons, since the disruption of the electronics at landing, even if reversible, means a crash. Such a weapon was suggested to explain the car crash that killed the princess Diana - in case an external explanation were necessary. Though, I feel similar weapons that stop temporarily the brains working, probably adapted (since 1992 in France) from Transcranial Magnetic Stimulation (Wikipedia), are an easier explanation. What effect on a car? From a flux compressor at 10m, at least all electric circuit are destroyed, even without electronics. At several 100m, civilian electronics is destroyed. Reversible service loss of unprotected electronics must occur at maybe 1km - not quite sure. A strong, unadjusted switch-and-antenna would destroy sensitive electronics at 10m and probably more, disrupt its operations at over 100m, which means a car crash because of ABS and the like. This has been demonstrated by amateurs. The effect of a strong EMP on the brains is an other worry, even if the weapon is not designed specifically for that. I suppose the driver is disabled, which produces an accident as surely as disabling the electronics. Other means exist, alas. Cars carry a remote control to disable them. This has been demonstrated by hackers who could use it. I may have seen it in action in France on a Peugeot-Citroën car. As usual, this foolish weakness in nations' resilience was introduced by governmental agencies in their countries; as usual, this was to improve law enforcement, safety, blah blah - and is one means more for the government's thugs to control people.

Any heavy object passing too near would disrupt the Solar system. A speedy object less so.

Thanks for your interest! If Czochralski permits to produce chiral solvents for cheaper, it may spread their use. Crystallization would be made either from a melt (improbable, as many organic compounds decompose before) or from a solution. All processes use a solvent, Czochralski is just a far better controlled process. Only for organics, or even only drugs, which are the essential reason for chiral purity. If Czochralski can produce pure enantiomers of a few standard acids and amines, which in turn permit to screen drugs, I'll be satisfied. I want to use standard crystallization temperatures. Maybe the link from silicon to organics wasn't clear enough. Silicon is crystallized from the molten element, but organics should crystallize rather from a solution at a reasonable temperature. And, yes, only a few compounds are known to separate spontaneously into left and right (I suppose the isomers are separated in a previous step usually). To my understanding, these exceptional compounds serve to screen others, for instance: a pure left amine makes with a racemate acid two amides with different crystallization properties, because the two amides are isomers but not enantiomers. Hence the usefulness of having these special compounds abundent, pure and cheap.

Silicon carbide exists as a compact material. The linked examples are agglomerated, hence they would leak. Cutting SiC should be avoided, yes. You better sinter it from the beginning in its shape. Are you sure you want SiC? Many ceramics exist, and 300°C is nothing for them. The most common (after clay and porcelain...) is alumina. Zirconia is rather common as well. Alumina exists as a powder that you mix with water (just like Portland cement) and mould in the final shape. Slightly easier than compact SiC, but damned expensive as well, are carbon fibres in a silicon matrix. Carbon cloth is put in shape, liquid silicon is poured to soak it and maintained for some time. SiC forms by dissolving some carbon. Brake materials for Porsche are made that way. Available on request, we paid like 200€ for each 10mm*50mm*300m part in a previous job.