Engineering

Hi there, My first post here Can compressed air be used to direct a helium balloon? I want to make a device that is highly maneuverable. I was thinking some sort of directional nozzles does something like this exist, or is it impractical? Many thanks, Steve

Anyone know?

I want to build an RC car so I can familiarize myself with the machine shop at my school. The car will be simple and I have everything figured out except the differential. I want to put an electric brushless motor on the rear axle, but I don't think I could just have 1 drive shaft for both rear wheels and gear it up that way. I need to figure out how to make a differential so the outer wheel can rotate faster during turns. I know most RC cars have some system like this but I haven't been able to figure out how it works. Also I can't seem to figure out how to invent one myself so I need some links/ideas. The tools available to me are: precision lathes, 2-axis m…

Is there any way to have a 30cm ⌀ source of intense enough white light beam to reach a couple of hundred miles with the least divergence possible, perhaps up to a mile ⌀ ; by 'cheap' methods/lensing/whatever ? A lighthouse fresnel lensing can neatly reach 20 miles; what would it take to make it 200 ? How do airport beacons work ?

Hi all. How can light from multiple sources be simultaneously directed to a single area/direction ? Is there any unusual -or not- shape of lens/material/coating (cone, dome... ?) that refracts light incoming from any direction and bends/focuses it towards the same spot ? Those "solatubes" installable on roofs gather light from nearly all directions and by its mirrored internal surfaces tube it is 'piped' to a single 'destination' If a chamber had its 4 walls and ceiling covered with light bulbs, what optics contraption could be placed in such chamber so the light hitting the contraption be channelized/ducted/refracted/conveyed to the surface where it stands ?…

How are microthrusters fabricated? Are they made by the same fabrication techniques used to make computer chips?

How our World and our Universe were made is a question in our minds, and it is our concern. One can raise the question of how everything was made. Do we have an answer for this question? How was our universe created, and what is everything made out of? Let us think of all the planets, moons, and stars in our universe. Our Modern Science mentions the Big Bang Theory. It is said that what made our universe were clouds of dust and gas. They say an explosion took place; these materials exploded, got together, stuck together, shaped up as spheres, and made up our universe, as moons, planets, and stars. Could this be true? What is ARCOS Theory? ARCOS Explains what ever…

So, I've been looking at compressed air cars: http://www.popularmechanics.com/automotive/new_cars/4251491.html They apparently have zero pollution and low running costs, and seem really really cool! Any idea as to when I can get one? On a more serious note, is the air car a credible alternative to the gasoline cars that are polluting our atmosphere?

What would it take to store all that lack of heat from tons of snow and cold days to be released later in the summer; and all that heat from the summer to be released in the cold of the winter ? Dreaming to eliminate the heating/air conditioning costs on dwellings. A basement or a large room filled with thermal masses ? With some 'magic' material with a huge heat absorption coheficient? Plain rocks ? Scrap metal ingots ? The subsoil, at around 40 feet deep, the temperature is a nearly stable all year to somewhere by 55 F. There is no chambers with thermal insulation walls in there; nature works fine. Injecting some fluid in there? Geothermics works. …

Hello, i was wondering what is the approximate size of a capacitor that would charge to 128vdc aka house power. and what is the electron dissipation rate for such a capacitor. don't really know where to put this so ill try here before moving to physics

I am in need of a non-contact liquid level sensor for small drums. I found that Madison Co. has created a ultrasonic sensor with a range of 4” to 70”, it be used on 30 and 55 gallon drums and requires no software installation or programming. I was wondering if anyone knows of any other companies that make such a sensor so I could compare them and see if they are worth buying or if I should make my own?

First off we have all heard of the tether into space. How much heat could a pressurized helium filled carbon nanotube chamber take before bursting and would it be possible to make such a device? I want heated gas tube inside and helium filled sectional valved outer wall in order to sustain the weight of the tether. The heated gas inside would be non explosive. I do not know anyplace else to discuss this or I would have tried there first.

What is the Thrust to Weight ratio? im planning to build a scale model of a floating island. im going to make it out of toothpicks(building materials), a mini thermonuclear reactor(energy) and fans(propulsion). for the purpose of having a floating, controllable runway with the ability to land other model planes on it. i wana see if it is even possible to make such a thing.

i want to learn about mechanics such as the movements of a bionic arm, but since it is a decently new topic in science, i wouldn't think i might find much. So if you can recommend a good reliable book that just introduces mechanics to its reader would be fine..

Hello, I am looking for some freeware that would allow me to take a scanned topography map and run a hydrolgy analysis. I would like to simulate a rainfall to see where the runoff accumulates. I have no budget for this which is why I am asking for freeware advice. I know the answer might be a complicated process involving several small programs. Any help would be appreciated. Thank you

In digital-to-analog converters, what is charge redistribution? Does it have something to do with switched capacitors?

I'm desperately trying to verify a FEM analysis done on a system of two permanent magnets. I'm trying to analytically find the force between two large neodymium magnets spaced 1/8 inch apart. This problem would be easier if the magnets were oriented such that their magnetized planes were parallel with each other, but this analysis requires that the magnets be PERPENDICULAR to each other. Since the magnets are close to each other, considering the dimensions of the magnets themselves, I cannot make the magnets into dipoles. The question is, then: HOW DO I ANALYTICALLY (NO FEA OR ONLINE CALCULATORS) determine the force (normal and transverse) between these two perpendicu…

In the wikipedia article on solar thermal rockets they write that: "Direct solar heating involves exposing the propellant directly to solar radiation. The rotating bed concept is one of the preferred concepts for direct solar radiation absorption; it offers higher specific impulse than other direct heating designs by using a retained seed (tantalum carbide or hafnium carbide) approach. The propellant flows through the porous walls of a rotating cylinder, picking up heat from the seeds, which are retained on the walls by the rotation. The carbides are stable at high temperatures and have excellent heat transfer properties." What is a retained seed? Is it a crystal?

What future technology will allow us to make computer chips smaller than 1 nm?

we are experiencing what appears to be a slow air leak in the following setup: low pressure sensor connected to a tygon tube via 1/8" hose barb; the tygon tube is submerged in a liquid; the hydrostatic pressure of the liquid compresses the air in the tube; the sensor measures the air pressure; the linear relationship between hydrostatic pressure and liquid level enables liquid level determination problem: over the course of several weeks we've noticed a slow, steady drop in pressure while a constant liquid level is maintained. of note, the small "slug" of water at the bottom of the tube climbs slowly and steadily indicating an air leak. two questions: 1 - if…

Hi all, this will be my first post. I have decided to attempt to build my own wind turbine using canablised parts for as cheap as possible. Iknow I can get the wind to drive a permenant magnet motor. But which one? I need a high voltage (30v ish), high current, low rpm (400 ish) motor that I can canablise Any ideas? Thanks in advance Tranq

I didn't know where to put it but I think it belongs best to electronics. In How a Projector works? they write that the composite video and S-video signals are routed to a Video Decoder circuit. Most digital projectors include a video decoder and a light engine. The video decoder converts video data received by the projector into pixel and color data. My question is: How exactly does the video decoder do this conversion?

I've been doing some digital electronics in my studies lately, and I'm just not getting this part. Well, rather, I can do all the work just fine, I'm just not understanding something that my lecturer claims is unimportant. I'm sure many of you know what it is, but to make the problem I have clear I'm going to explain: S NAND (NOT)Q = A = Q R NAND Q = B = (NOT)Q They both seem simple enough, but I'm not getting how it /starts/. On start-up, S and R are defined, but I can't fathom how S[or R] NAND (NULL) gives a value at all. My best guess would be to set S and R = logic 0 to start with, so that regardless of (NULL) the NAND would be logic 1, but A and B can't…

Can anyone help me with this problem? I have a large glass bottle washer in the factory in which I work. The bottles are transported around the machine (upside down) in round metal carriers. As the bottles travel thorugh the machine they are subjected to a variety of treatments to enusre they are clean. After the treatments are complete the bottles enter a spray rinse section which uses a blend of hard and softwater to achive a hardness of around 120ppm. Once the bottles are finished in the rinse section the bottle carriers are turned 180 degrees and we rely upon gravity for the bottles to fall out. If we drift away from this hard/soft water mix of 120ppm the bottl…

Long ago, I read in a science-fiction novel about a guy that went skydiving from orbit. He had on a spacesuit with ablative plating and everything. My question is: with today's technolgy, is it possible to do that? Assuming we had a really well-built spacesuit with ablative plating and some means of deorbiting, can it be done? Assuming it can be done, can we drop the prospective thrill-seeker at a given point on the planet, and if so, how much accuracy can we expect? I'm not picturing landing from orbit onto a moving vehicle, but perhaps getting within a few miles or so of one's destination sounds nice. On a related note, what's the smallest orbital vehicle we have th…