Engineering

Hello dear friends! I believe it is known, but not universally: a quiet amplifier can synthesize a quiet resistor that produces less noise than a physical resistor at the same temperature. Amplifiers can be very quiet. Under S/N=3dB they add less noise than a resistive source at 300K produces. Good RF preamplifiers of usual technology at room temperature can offer S/N=0.8dB, adding 20% to the noise power of a resistive source. Cooled or exotic RF preamplifiers can be much better. Audio amplifiers can add even less noise, especially FET amplifiers on a high-impedance source. Here the amplifier with gain -A shall have a high input impedance to simplify the co…

Shown on some reports of third world innovative diy gadgets, they have a led lighting a water filled soda bottle. (This is not the 'skylight' similar approach that funnels sunlight and rain leaks into a dwelling) How does the addition of the soda bottle optical losses improves illumination than the bare led alone ? The difference I see is it creates a non-point of light emission by being a bottle-sized body of emission with some according gentler pupil reaction. Now, the "old" battery mentioned. Why old ? Next, about the skylight bottle. Why is it perceived better than a transparent piece of roofing ? Is it from the strong habit in modern off…

All of the electrochromic film I have seen for sale operates on the principle that when electricity is applied, the film becomes clear, and I understand why that is...but is there an electrochromic film on the market which operates in the opposite way? Is there a film which remains clear or semi-clear until electricity is applied, after which the film becomes opaque?

How do I make a coil or a series of coil constantly move electricity as the magnet passes it in half of a circle/armature. Do I simply make an oval shaped coil that covers the area I needed cover, or do I make a series of coil? Think of it like a motor but instead, the coils are only on half of the armature.

If I needed to generate an adjustable current up to a maximum of .000165 amperes, what would I use as a power source?

The engineering that goes into this aircraft is amazing! I've never seen anything fly like this other than a frisbee!

That 2001 movie and its turning module to make gravity seemed within reason... Why has not been pursued ? No need for it ? Cost ?

I'm asking for suggestions in various categories as some of them might be more important for coursework whereas others might be more recreational and to expand knowledge. I know for example that Knoll is the go to for radiation detection and Lamarsh and Baratta is the most important for intro to nuclear engineering (of course some disagree with dumbing down in it, which is why I ask). Any books that anyone would like to recommend as a must have for core nuclear courses? Other books that I'm looking for are more for my knowledge. For example, I found introductory nuclear physics by krane really helpful in explaining some of the concepts and bridging the gap betwe…

I've been trying to put the math together for this, its out of my league. What i need to answer is: if each charged plate strips/adds electrons to the air molecules they touch, will this configuration of insulators and charged plates produce positive thrust along the main Y axis? -DT PS, "Tah-Dah!"

You can create your own desalination pit in your back yard. Just put a clear plastic sheet over a kiddy pool and have the plastic deliver condensation into a central bucket. Why cannot humanity build desalination containers to float off-shore, like a fleet of a hundred (or thousand, or million) canoes covered with clear plastic. They float on the ocean allowing just enough water into the container so the sun can heat it and the condensation can flow through pipes or hoses towards shore. These containers can even be connected by "wigglers" that generate power from wave action. We could irrigate great deserts to grow trees to capture greenhouse gasses and d…

Hello everyone and everybody! The elastocaloric effect is one more fascinating behaviour of NiTi alloy and other materials including rubber. NiTi, whose crystal can change between martensitic and austenitic easily and often reversibly, is known as a shape memory alloy. But as the heat of formation of the crystals differ, the transition absorbs or releases heat, here when provoqued by mechanical stress. Refrigeration and Niti on Wiki Research tries to build fridges, air conditioners and heat pumps using this effect. NiTi operates around adequate temperatures, survives many cycles, offers some 30K swing, and promises efficiency at least when exploiting its full …

Hi, I have a problem. I need doing simulation in AnSys about explosion methane (as gas), unfortunately program has not such material and I do not know explosion parameters of methane (8.5% in air). I am enclosing picture with parameter of TNT (AnSys has material TNT), and does someone know about what parameters should has methane gas and could you share with me? Best regards

I have a really neat idea. Engineers should be able to build a car that travels on land, air and sea. The main method of locomotion would be in the wheels. For travel on land, the wheels would be vertical, and travel on roads, which of course is possible. They are just called cars, or possibly landcars. For travel through the air, the wheels would slowly turn to a horizontal position, and start rotating within the tires. The wheels would have small wings in them, which would provide lift when rotated. The car could take off and land vertically. The cars would be called aircars, skycars, or flying cars. For travel on the sea or lakes, the car would be driven…

Hi, I see a film series on Netflix called "Better Call Saul". There is a guy called Chuck (Charles). He is allergic to electricity so he can sense if there is electricity. His brother had a guy put a fully charged battery from his phone inside Chuck's pocket without him noticing it and he didn't sense the electricity. Therefore his brother though he was mentally ill. I wonder, is there a current if the battery is not in use? Should he even have sensed it or is his brother mistaken?

Was anyone watching this? It took a long time for the news to even mention that firefighters were trying to get close. It took a half hour for ONE fire hose to start on the fire. Can anyone figure out what is wrong with the performance of the Paris Fire Dept? I suspect that the fire trucks had trouble getting through barriers for terrorists. Why not scramble tanker planes to drop water on the fire? Were there any local fire hydrants? Can anyone figure out how to prevent this happening to other historical buildings? Maybe install a sprinkler system, I don't know.

Hello everyone. As part of a school project, I would like to make a machine similar to this video: https://www.youtube.com/watch?v=VtTZ855O5ds&t=107s, to convert the mechanical energy of the swell in electrical energy.However, with little knowledge of motorization etc, I would like to know what types of generators and / or DC motors would be most suitable for the system presented on the video.Thank you for your help.

I'm doing a project that requires gears and don't need/want anything expensive, so those hobby gear-kits look like they'll work, but I need the gears to be a specific size, and the only ones I've seen just come in standard sizes. So I was wondering if anyone knew of a site online that sells inexpensive plastic hobby gears custom cut to size? Thanks.

Hello nice people! Metal Matrix Composites (MMC) mix ceramic powder, nanotubes, other small things with a matrix of metal like magnesium, aluminium, titanium, iron alloys. The goal is to increase the stiffness, the compression resistance, have a small density, and hopefully keep a decent tensile resistance and toughness. I haven't searched for long, but apparently they use a single range of particle size, to about 40% volume filing factor. Though, a suspension becomes quickly a slurry, and with about 40% volume of solid particles, it doesn't flow any more. I understand that particles touch an other as their arrangement isn't optimum, so they immobilize the suspension,…

I'm currently trying to choose a lattice structure/geometry that finds the tradeoff between strength (for compression & shear mostly) and heat transfer. I want to maximize strength and minimize heat transfer through the lattice. Does anyone have any recommendations on this front? The less material, the better! Thanks a ton in advance.

How to neutralize mind control please?

Anyone have any suggestions for a strong material that can be used in a 3D printer, but has super low thermal conductivity?

Explosion and reported brief radioactive contamination at a Russian missile test facility in Nyonoksa, 47km from Severodvinsk https://www.bbc.com/news/world-europe-49301438 https://thebarentsobserver.com/en/security/2019/08/latest-rosatom-says-five-employees-killed-blast-while-testing-isotope-and-liquid https://www.france24.com/en/20190810-russia-says-five-died-missile-test-explosion https://www.rt.com/russia/466194-rosatom-killed-arkhangelsk-blast/ https://www.thedrive.com/the-war-zone/29356/russia-admits-mysterious-missile-engine-explosion-involved-nuclear-isotope-power-source the newspapers of varied origins and quality seem to have very few sources, Rosatom and the …

Hello I am building a spacecraft at my garage . For engine I have compressed air inside a closed box and by pressing a button I create a small gap where the air could come out . My box is made of a material tough enough to resist the pressure of the air inside . Also it is not very ductile meaning it cannot be easily plastically deformed resulting in reduce of the pressure . Now I want to make the body of my spacecraft.Any ideas? P.S I want to go to and die at the Moon so I can have the incredible view of Earth for the rest of my life.

Is this concept acceptable for a non-nuclear atrocity believer? HIGH BANDWIDTH CONVENTIONAL SUBMARINES CLOSE TRANSFER WITH THE GROUND Maybe, we could achieved an international network, dedicated to nuclear submarines efficiency, that way reducing the response time, so the risk associated with such lag responses :() :() :() The formidable investment, will be rewarded by a new era of stability :() My first estimation, for a complete network mapping of all oceanic floor, in case of an alien invasion : 361 132 000 km² of oceanic floor 361 132 000 / 25 = 14 Millions km …

Hi. These single-hose 'portable' airconditioners... how can they cool any room at all ? The hot exhaust expels the heat from its condenser cooled by the room air cooled by the evaporator + the heat extracted from the room air by the evaporator + the building heat entering the room under the door and leaks + the compressor heat. Can someone explain ?