Engineering

What do these symbols mean in electronics? [math]V_{DDH}[/math] [math]V_{DDL}[/math] [math]V_{SSH}[/math] [math]V_{SSL}[/math]

http://en.wikipedia.org/wiki/DEMO DEMO is a power plant whose conceptual design is set to be completed in 2017 (following lessons learned from ITER) and construction set to complete some time around 2033. The goal of the power plant is to continually produce approximately 2 gigawatts of electricity, and demonstrate the practical feasibility of fusion power as an energy source.

A question has been prompted in my mind, from another forum ( guitars) about the 'feel' (tension) of guitar strings: If two pieces of wire with the same diameter but made from different alloys (bronze and phosphor bronze) are brought to the same tension (pitch), would there be any difference (everything else being equal) in the amount of pressure required to move them laterally ie press them down on to the fret? I don't think there is because metals don't have longitudinal elasticity.....what's the fact?

I have been asked to design a system to measure the force being applied to the working face of a system. Basicly it is a class two lever and i want to measure the force being applied at the load point. The image below shows the object where the load is being applied. The load is applied to the inner face on the left hand side. Can someone suggest a location where I can find information on how and where to attach strain gauges to measure force on such a face?

I'm new to this forum but I'm a science geek. Sorry if this is way off topic for your forum but I thought this would have enough science involved to ask this question and hear an intelligent debate. The car in question is a MR2 Turbo. To cool the engine bay on a MR2 turbo there is the radiator mounted up front and passive cooling over the motor; Air rushes under the car and out the vented engine bay hood. The conflict is that a common modification to the car is putting two 11 inch 850CFM fans under the hood vent. My personal hypothesis on this is that the fans would restrict air flow because they can only move 850CFM thus a limited RPM. A sales rep. told me …

Hi: Which method of radio transmission/reception for wireless computers is more secure -- Frequency-Hopping Spread Spectrum or Direct-Sequence Spread Spectrum? I believe the former is more secure than the latter because it does not constantly remain on the same frequencies. Am I right? Thanks, Green

I'm about to take a vacation to another country, and I'm worried about getting mugged and robbed. I've been hearing recently about a rather new piece of technology that is designed for just this sort of thing. It's called the Technobra, and it notices a jolt in your heart rate and uses GPS and wi-fi technology to alert the authorities of your name and location, so that they can find you anywhere in the world. The problem is: I'm a guy. Is there any kind of this technology that I can use on my vacation?

hey, i want to make a RC helicopter from some old RC cars i used when i was young. some of them go pretty fast so im pretty sure it can get off the ground with one of the engines or whatever moves the wheels on the car. i dont know much about building an RC helicopter though because iv only taken apart the cars and i dont even understand them much. i need help with pretty much everything, what turns and rotates the helicopter, how to make the battery i want run the engine i want, how to make the controller i want work with the car parts i take. im not sure how close i can get to a RC helicopter befor i have to go to a store but if anyone knows links with useful in…

I want to build a home made electric RC Heli, very small and light. I have one of those Mini RC racers, like these and i want to convert one into a heli. They are powered by capacitors, but I don't know If the motor and all can produce much thrust. I can make prop blades out of nylon to keep it light. Does anyone have any suggestions, ideas, or even better; has anyone actually made their own electric micro heli? If it won't work to make it out of the car, what can I use? I want to use capacitors, because Li-Po batterie cost too much. What motor should I use, etc. Thanks for any advice.

Hi 1. What is the benefit of using Fourier analysis? 2. What is the difference between time domain and frequency domain? Regards

Hi all, Can you help me with this question ! What is the range of the frequency that is received by mobile phone? Thanks

How does the device briefly shown here inside a cabinet works ? http://www.youtube.com/watch?v=V1IfzVrNqtU&feature=related The output seems to be a detergent injected with microbubbles. How does the mixing produces the bubbles so small ?

My friends and I were thinking of building an air cannon, to play around with motion equations, and secondly, to have a blast by utilising it in various ways. The conceptual idea is pretty simple, a cylinder of pressurised air, connected by a butterfly valve to a relatively long, rigid PVC tube, which would act as the main barrel. We were then thinking to then mount our settup onto a a flat wooden base, and then simply add an axel, on which one could regulate angle. As I said, the idea's simple, but I thought to ask some more experienced members here, for perhaps some hints in regards to how to achieve optimum performance. Any thoughts?

you want to design a: 1-cannon that will blast an: 2-object as high as possible in the atmosphere, and again, reaching outer space is a bonus.. what are your ideas for 1 and 2?

any reason why it would not be possible to have two sets of blades on a turbine. one would be in front and would turn the first rotor clockwise and another would be behind and turn a second rotor counterclockwise.(no stator)so the relative movement between the two rotors is much greater than the movement for one rotor and stator in for the same wind blowing at it. the first rotor could have 3 blades like a standard wind turbine. the second rotor obviously is blocked whenever it is directly behind the first so it would have maybe six? (or more) so that some blades are always exposed. so the rpm of the standard turbine would be x rpm relative the rest of the turbine. …

MORE INFORMATION ABOUT NDE RESIDUAL STRESS The residual stress in a metal do not depend on it hardness, but from the module of elasticity or Young module and from its chemical composition (density). The hardness of a metal indicates its ability to absorb energy elastic, plastic or kinetic energy, but through it not possible to determine the value of residual stress. In a metal with the same hardness we will have a different values of this stress. Therefore, the problem will be to measure the values that vary so exactly proportional to the residual stress values in a given metal. The residual stresses tend to equilibrate themselves in the surface of the material. …

Do you think a Stirling motor can be used to power a small automobile with at least one person inside? Im guessing that with me in it, plus the motor and the body Im drawing out, it will be about 160-180 pounds. Could a stirling motor push that much on wheels do you think? Ive been wondering this question for a while. Im currently making my own stirling motor, and am wondering If you guys think If It would work or not. I beleive that It will, and I will probably still try even If Im told It doesnt work, why not. Im not so much worried about speed, just so long as Its a bit faster than walking, Im cool with it. Im tired of walking 1&1/2 miles to school twice a…

Which of field engineering is most useful & demandable in todays world? Merged post follows: Consecutive posts mergedI think so energy engg. & mechanical engg.

I want to bend some resistor wire into a coil shape and then insulate it electrically. However, the coil will be used to stir and heat liquid so the material must not insulate the heat from the resistor wire. I would also like to experiment with this at home so can it be achievable in a DIY sense? The coil will be no bigger than a hand-held whisk (just for an example of size!) Any ideas welcome Thanks Paul

Is there a material(preferably some sort of clear or white crystal) that will give off light when exposed to low levels of heat(like body temp)?

wasn't sure if this belongs in this section but its here now.. To be clear, this isn't a fanatical thing or talking up the movie. I like most of the more recent movies for what they are, movies, but they have a very logical and real use of the possible technologies we are looking at. wouldn't think I am the first one to think of this so direct a link if anyone knows of anything related. existing technology, ideas, theoretical ideas or trialed technology, etc... the question for discussion is, with the idea that the power source was possible now, in what ways would a suit similar to that in Iron Man be made? in relation to the mechanics of the movement of it,…

Hi everybody I have a question about a solar-assisted cooling system ,used to cool milk The systeme basic components are electric compressors and an absorption machine, When optimizing the compressor cycle, by lowering the temperature in the condensor, an important saving of energy can be made...........this lowering is the result of introducing the absorption machie ............; my question is: how does the lowering of temperature in the condensor influence the electric energy consumption? i mean how could it be calculated? for instance, if the compressor cools a volume of water at 7°C (instead of 9°C) to bring it to 2°C (knowing its capacity (2500kw) effi…

Alright, so I want a small, {inch or two}, sensor of some sort that, when bumbed, {just slightly}, sends out an electrical signal. What should I use and how much is it? Thank you.

Me and my friend have gotten into sword dueling...not serious dueling, we just pick up a couple of sticks or something and see who can hit the other first. Anyway, since I've always been a with Star Wars fan, lightsabers have always captured my attention, specifically how to build one. And ever since we started dueling, I was attracted to the possibility of making a training saber. The way I envision it, it would basically be a piece of metal with some kind of voltage going through it, so that it would give a jolt whenever it came in contact with skin. It would certainly make the match more fun, since the opponent would have to guard himself even against the smallest brus…

you want an object to reach as high as possible in the atmosphere, if it reaches space, even better... how can you do that while attaching it to a balloon? this includes a lot of physics and design, maybe even chemistry, but a LOT of innovation..i have some ideas, but wanna hear yours first.