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Hi Cap'n ...."That would work if all of the noise was of the same wavelength "... Can you please explain, I want to understand your thinking. ¿Is it related to the distance travelled by a valley and a peak of a high frequency is much shorter than at a low frequency and that would determine the needed lenghtening of one branch?? I see something there, but unclear. The noise in EACH branch of the pipe would be EQUAL at all moments. One branch would have to be delayed properly... I think. Even if the bang, bang, bang, source noise changed to bing, bang, bung, will still be the same in each branch, the point is how to achieve cancellation. And the speed of sound propagation is a constant. reng, For a nice initial question, you do not know what you are saying on you last reply. It is to cancel the noise, not the bursts timing:-( Miguel

Hmmmm.... A mousetrap provides a considerable force during a 180º half a revolution short travel; and what you want to move (¿a propeller?) takes comparatively much less force and much longer revolutions... If you can come up wth a set of gears to use the spring force to multiply the spinning, something could kind of work... briefly. Like a wind-up toy. Miguel

Hi. Not much that I can help with, but your question touches a point that has always been spinning in my head... Imagine that a SINGLE pipe collects all the cylinders exhausts; if that pipe is split in two equal branches downstream; they both carry in-phase pressure waves along their lenghts... The peaks and valleys of the noise waveform coincide equally along both branches. By the law of physics, if both equal branches are joined together later downstream, the peaks and valleys would add and the noise result would be again the same. But if one branch is made a certain amount longer than the other, in such way the longer branch yields 180 degrees out of phase noise, joining them again downstream would cause the peaks to be cancelled by the valleys, attenuating the noise to a theoretically great degree. Or am I missing something ? How could this cancellation of waves principle be achieved? Miguel

Hey Scientist 5614 : ¿Can you read the word after " /stuff/ " in your link ? Try in reverse ! Still believe it possible ? Miguel

Hi Neonblack. The very hot stylus playing a phonograph record touches a location on the vinyl so briefly, that does not burn it. Like passing your hand over a candle flame. The speed at which the record groove passes, does not give a chance to melt. But repeated play does show the wear effect. That is one of the reasons records were changed from original 78 rpm to 33.3 To reduce stylus temperature. I think a very focused laser thermometer could read it, if can be properly aimed. Evercurious : I would really like to enjoy your calculations whenever you have the opportunity. For the radio waves, I have seen insulators burned at the base of ~100W mistuned antennas. Put some aluminum foil confetti in a microwave oven and if you can measure the temperature, you will have your answer. Or put a junk CD held vertical inside a microwave oven for 3 seconds and enjoy the show... Miguel

Hi. Rent "The bedsitting room" movie. It's all there, plus the weirdest scenes you can imagine. Miguel

¿ Heating something with the power source from a Universal Serial Bus connection ? Well, you will be able to connect a 6 V portable flashlight bulb, maybe two as a heat source. That is about how much heat you can obtain from it. The USB power is +5Volt, current limited to a number of milliamperes determined by the USB chosen integrated circuit specifications used by the manufacturer of the motherboard. If the current is limited to 500mA, the maximum power obtainable is 2,5 Watts. You may try to connect a rheostat and measure at what resistance the voltage drops 5% to 4.75V. That is as low resistance as you can connect to drain power from it. Should be around a couple of watts. But all this near senseless aproach can be done much better by tapping to the +5V PC power supply line, capable of much, much more current, maybe 50 extra watts, instead of playing with a power weak USB port. Miguel

Hi. The fog deposited on the windshield is condensed vapor from humid carpets caused by wet shoes entering the vehicle, a wet umbrella, a leak in the heater core or poorly sealed door/window and blown towards the cold glass at several duct points. Miguel

Hi. You say "...an incredible amount of heat... 1500 degrees C... " (in an instant) That is not heat. That is temperature. Yes, it is done every day, millions of times. You too : Turn on a light bulb. I do not know exactly the temperature, but an halogen lamp filament should be very close if not beyond 1500 C. A turntable needle also does get that hot. Fast. But its MASS is small, which means its amount of HEAT is too. Miguel

Yes, look at a plain car cigarrette lighter. That is what you want, already made and available. My seventysomething Chevette did have under the carburetor, an electrical heating grid, about half inch thick to aid vaporize gasoline. You can find one at the wreckyard and recognize it by a couple of thick wires getting to it. Miguel

Hi. Do this: connect the speakers from your stereo together; (no amplifier at all involved) gently push/tap one cone and observe the other following nearly the same motion. With sound, the motion is much less, but happens. The sound becomes an electrical signal , goes trough the wires and becomes again vibration at the other speaker. Miguel

No, your question is not idiot, but perhaps lacks the words "fully reversible" There is no such thing; there is always losses, its one of the laws of physics, you just need to read more about the basics; and in the future when you re-visit this same post, will understand the responses. No, you cannot inject heat, carbon monoxide and smog into an automobile exhaust pipe to make the engine turn and expel clean air and fill the gasoline tank while getting a ride. Even with piezoelectric or motor/generator, cannot recover the same amount of electrical energy by reversing the action. Miguel

Hello. If I understand your question, you are trying to electrically heat something in the most efficient way. To heat water (or something else) as you say, there is NO more efficient way. Any electrical heater will work THE SAME. How many Watts you put in; and the temperature will rise the same amount with a modern ceramic heater, or a carbon resistor, a light bulb or a 1920 coffe brewer. The efficiency can be improved by confining the heat and eliminating heat losses with insulation, but a given power will always produce the same amount of heating. Go to a store and look for plain room heaters, you will see many models. If all are 1500Watts, all will yield the same heat, no matter if modern or antique or whatever the advertisement in the box says. Hope it helps, Miguel -I do not know what you mean by USB-

Hi. If you only have wire and a piece of iron; and cannot read schematics, forget about building an inverter. Go to a computer service center and politely ask for a discarded Uninterruptible Power Supply UPS. They are usually discarded when batteries fail, but all the guts still may work. The guts are exactly what you want: an inverter. Miguel

Hi. This is not my field of expertise at all, am begging your assistance. In a gasoline automobile engine, given the intake manifold absolute pressure, the displacement, the revolutions per unit of time, the air temperature and a throttle position reading ; is it possible to precisely calculate the air mass flow ? Or more information would be needed ? Miguel

The excavator won't be capable to push it in ? Then have the excavator removing soil from nearly under it until it falls into the hole. Gravity always works. Miguel

Hi. Hard drive motors do not have enough torque to use them as propulsion on a RC car. But they could be used for RC airplanes. The plan to use hard drive motors just because you have them at $0 is not a good decision as they add too much complexity to your project. Their control circuitry is meant to spin them at a steady speed to ensure data stream uniformity which does not go well with other applications. Miguel

Hi. Dig a huge hole in the ground next to the rock, and push it in. Then spread the soil all over the yard or where needed. Will take you 15 minutes of excavator rental. Miguel

Hi. Three terminal hard drive motors are three phase motors. You will not make them spin applying 12V DC to them. Follow the traces of those three terminals and do a web search for the integrated circuit that connects to. Look for its application notes and then you can saw-off the portion of the board containing the circuit and ancillary components to make it run. Miguel

NOPE !! The refrigeration compressors -or pumps if called that way- do NOT pump ANY liquids. They handle ONLY gas. The compressed gas becomes liquid AFTER it is cooled in the condenser stage downstrean the compressor outlet. After they absorb heat in the refrigerator evaporator, the refrigerant becomes gas again and that is what enters the compressor inlet. Compressors do not compress liquids. They are almost incompressible. Miguel

Hi. Yes, gases as refrigerant gases, air, etc. Seen it done to evacuate chambers; and can be improved as shown here: http://www.sas.org/E-Bulletin/2003-12-12/labNotesAS/body.html Miguel

Hi. Use the inlet side of a compressor rescued from a discarded refrigerator. It really sucks ! Miguel

Hi. Use paraffin as a filler in a box sorrounding the electronics instead. And consider a tethered robot if you want real time video. Miguel

.... And if you use the laptop on batteries, does the television gets interference ? If it does, you will be chasing your tail with the wall outlets; the interference is radiofrequency emitted by the laptop and picked by the television receiver with not much to do with the electrical wiring. Miguel

Hi. Yes, what you describe is commonly used to heat homes. But you do not need mirrors, you need the pipes painted black in a sealed box with a glass cover. If you circulate air trough the pipes, it will heat the home during the day. If you circulate water, it can be stored hot in tanks and its heat released also during nights. You can obtain about 1 KWatt/m². Make it 5m x 5m on top of your roof and your home will stay toasty all winter. Search for "solar heating" Miguel