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What is the propagation speed of radiant heat?

How does heat radiate ? What is that emission of heat ? Is it some sort of rays, electromagnetic waves, particles, molecular vibration ? A body placed between a radiated heat source and its target can block or absorb it. What is actually traveling trough the air from the hot body to the being heated one ? Miguel

Could SZn be used as paint, mixed in some clear base to be applied onto walls to provide some glow from its luminiscent properties ? Has it been done?

Hello all... Two identical air compressors in series, both running at the same rpm. But the second in reversed flow, as to force expansion of the air compressed by the first one. ¿ Will there be pressure in the pipe joining them ? A-------C~~~~~?~~~~~E-------A A= atmosphere C= compressor ?= is there pressure in this joining pipe? E= expander (reversed compressor sort of a vacuum pump) ------ = pipe ~~~~ = radiator or finned pipe or cooling coil Anyone remembers ROVAC ? Miguel

Heating a home in general is considered more expensive than cooling, if both energy sources are at the same rate. Cooling process is lossy because of the compressor, evaporator and condenser inefficiencies, but the temperature gradient overcomes those losses. Cooling happens when the temperature is about 32 Celsius, and you want to extract heat for a delta temperature of about 10 degrees to get a comfortable 22 Celsius. Heating happens when temperature is around 0 Celsius and you want to add heat to reach about comfortable 20 Celsius. The delta temperature is twice for typical heating, the cost is nearly twice for heating. If you want to heat / cool the same amount of degrees, cooling is more expensive. Miguel

Hello Am not familiar with such item being available on commercial scale, but will make a couple of phone calls and will find out some more. It is all about energy. I read somewhere that a person yelling non stop for cannot remember how many years, would produce the energy to warm a cup of coffe. Dealing with such extreme does not make it simple. Besides, the range obtainable in real time electrical transmission would be near nothing, surpassed in range by far by the plain voice range itself. A piezoelectric flame lighter strikes a crystal and creates a respectable high voltage at a minute current and for a brief moment, but the strike is considerable respect to voice induced vibration. Get a piezoelectric transducer out of a defunct telephone ringer -or many!- (the larger diameter the better) and connect it to an oscilloscope to measure its voltage, then load it with some resistance to simulate either charging a capacitor (diode rectification of course in circuit) or operating a circuit. I do not think it has to be much more efficient than talking in front of a loudspeaker and measuring its output as a microphone. I say piezoelectric because has a remote chance of surpassing the 0,2V of a Ge rectifier. Storing that energy for brief, very brief transmissions is doable, but in real time, cannot see it. Not much more I can think at the moment Miguel

Hi. A long antenna is not really necessary, as a pocket radio with a few turns coil on a ferrite rod and a few picofarads tunes to AM. A tuned circuit of a few microfarads and a coil on iron core can extract some tiny energy from mains radiation; of course a long antenna would improve it. Miguel

Hello. The nearest related technology I know of about your question is not that new, from an article in the seventies. An U.S. embassy in Moscow received a present from the russian government, a nice piece of folklore art or something like that and ended hanging on the wall of the ambassador's office after exhaustive inspection from security to avoid spyonage bugs. Well, they found much later the thing had a few millimetres long and innocent metal wire in something like a resonating cavity (think of a microguitar). That was it. A microwave beam was aimed to the thing from a nearby building, and the voices and conversations in that office modulated the wire tuned to the incoming beam, re-radiating or bouncing the signal picked by a receiver in another nearby bulding. Isn't that clever? Entirely passive! A piezoelectric transducer, to charge a capacitor with collected energy from noises could emit very brief bursts of data on micropower transmission to a limited distance, if a very engineered device is built. But the energy is way too small, unless your piezoelectric wafer is truly large and exposed to large noise, leakless capacitors for storage, etc... I don't see voice as capable of. An alternate power source may be the 50/60Hz radiation around us, collected and rectified by some sort of 'crystal radio' tuned to mains frequency. It is an interesting subject, keep stirring the idea, some will come out of it. Miguel

Hi. Sintering, coating, magnetizing, demagnetizing, anodizing, tempering, annealing, painting, stripping, cutting, punching, stamping, cleaning, lubricating, packing, gluing, labeling, engraving, burning, freezing, heating, cooling, drying, wetting, humidifying, compressing, expanding, oxidizing, tarnishing, dyeing, vulcanizing, deburring, polishing, filing, grinding, sanding, tumbling, hammering, bolting, nailing, crimping, screwing, insulating, measuring, calibrating, irradiating, there have to be dozens more... Hope helps somewhat. Miguel

Hi. ¿Was it April first?

Right. Most appliances do not care for the frequency (light bulb, toaster) some are slightly affected but the buil-in tolerances absorb the deficit (radios, stereos, computers) and some other will change its behavior (washing machines, turntables, fans... whatever has synchronous motors) Miguel

Hi In simple words, the core on a transformer (or electromagnet) is capable of absorbing a given amount (the point where it saturates) of the magnetism the sorrounding coil produces. That amount of magnetism takes some time to grow and decay every cycle of the alternating current. Different alloys or sizes of the core allow more (or less) magnetic saturation. That is why an electromagnet to pull automobiles and junk is not the size of a pencil. It needs to be bigger to handle such magnetic field. At 50 Hz, the time a cycle of power lasts is slightly longer than at 60 Hz, thus the core can reach saturation earlier if was designed/calculated for 60Hz, when driven to full power demand. Usually in typical products, that is not always the case, a 60Hz transformer should be capable of handling 50Hz within design tolerances. But by feeding 50 Hz in the primary cannot obtain 60 Hz on the secondary |(nor reverse) Hope it helps better. Miguel

Hi. The same transformer that works on 60Hz can be made to work in 50 Hz with a different iron core that will have a higher saturation cohefficient. Miguel

Hi. Go to a computer repair shop, and politely ask for a defunct UPS -uninterruptible power supply- that is destined to the garbage can, or get a rain check for whenever they have one. That's it. Usually discarded when its internal batteries die, you can connect yours instead and done. 12V in, 240V out. I have AC in my car with one of those. Miguel

Hi. ...."I've been experimenting with capacitors (50-100uF from camera circuits). I'm wondering how I can charge a capacitor. I can't just plug it into a source of EMF, I probably need to design or find some sort of circuit, right? ---->Right, and the best circuit is the one it was connected to within the camera. Use the whole thing and not only the capacitor. ...."What's the best way to charge metallic objects? I don't have a Van de Graaf machine and can't produce enough charge by induction by rubbing two materials. Can I use a capacitor to charge metallic objects?".... ---->You can charge a metallic object that is isolated by contacting the charged capacitor between the object and ground And yes, the capacitor from a disposable camera flash is rated at least 350 Volts, and around 150 µF. The 1,5 volt cell charges it to 350 V by means of that small circuit you didn't pay attention to. If you touch the charged terminals of the capacitor you will get the nasty giggles. Miguel

Hi. ¿Any modern progress in the subject, can it be done? Some rubber parts change their properties with time or exposure to something, turning soft and gummy... Is it because they were poorly vulcanized, or they are not rubber, or had a different manufacturing process ? Miguel

To pass and detect ultrasound trough a metal wall, the simplest way is to cement piezoelectric transducers as emitter side and at the other side as ultrasonic microphone. Attaching an oscilloscope to the last will show the waveform easily. What would be the waveform? Depends on the fed waveform, bouncing paths, elasticity of material, lenght of propagation, route, attenuation versus frequency response properties... You can obtain a piezoelectric microphone by removing the ringer of a modern defunct telephone. That will work. Miguel

Hi. Am back. Your launcher has to be obviously a plain swing. The egg will sit on a craddle which allows only exiting forward and keeps it from falling backwards or move sideways. A swing will allow precise repeatability by inscribing markings on a attached scale from which point should be released. The suspension strings should be not strings, but any solid wire, like galvanized, smoothly pivoting on steady eyelets... just for precision and repeatability. The swinging "sitting" launching surface carrying the egg will hit a stop at about 45 degrees so the egg launches at a 45 degree angle (UPWARDS and forward) not horizontally forward nor downwards. WHY? Because you want the egg to have the minimum AT LEAST vertical speed at the moment of entering the cup opening. Launching it upwards (I mean 45 degrees) by stopping the swing, the egg has no impacts at launch, just momentum and slides out of its craddle. Now the nice part... the egg will have a vertical speed component decreasing by gravity pull until it is zero (the apex ot the trajectory) THAT is the point where the cup opening has to be. The cup can still be two feet away, but higher than the launching point. Like tossing a basketball so enters the ring barely above it and barely in motion. At steeper launching angles, like 80 degrees (almost vertical) the cup entrance will be nearly 2 feet higher than the launching point, its vertical speed component will also reach zero, and the horizontal speed component will be much less than if launching at 45 degrees, giving even better chance of easy success. Make one, have your partner make another, compare and combine the best of both. Remember trying different lenghts of "strings" Miguel

Hey ! A medium sized cup means nothing ! Get the mandatory maximum internal dimensions to comply with the rules and make/carve that cup from sponge. A couple of inches bottom and sides should suffice. Try to make the egg enter in 45 degrees angle and glue the cup down so it won't fall. For the launcher, any precise repeatable contraption should work, make sure it won't impact the egg at takeoff. If you are good at basketball, can be launched by hand if just 2 feet away. Good luck Miguel

Only two feet away? Well, nobody said what size is the cup ! Get a huge and deep one, fill with water and calibrate your launcher of any kind by trying with a boiled egg of the same exact weight for repeatability. Miguel

Still lost in space... V^2 is VERY different from 1/V^2 And where do you get "potential V increases linearly with the distance" from ? Miguel

Sorry, cannot follow your thinking... I lost you. Your first post says "...E doesn't change ..." And on your post above, says "...the potential difference increases (like x^2)..." No clue what you are thinking nor saying. Do not know what do you mean by E, by potential; by x. If potential E does not change and capacitance decreases; energy will decrease. Miguel

Hi. If you increase the distance between plates the capacity diminishes greatly. Then, the energy does too. Miguel

- "A car battery self discharges if left on a concrete floor" - "Slowing the coolant flow in an engine cools it down because allows more time to release the heat at the radiator" Miguel

Hi. Make an instrument to measure the propagation speed of gravity. Miguel