Engineering

A Flash Evaporator? We have one in our school, and my teacher was going to throw it away, i put it back in his room though, because i thought that i might as well just ask here to see how it works, and what it does here is a link, we have the exact same one: right here thanks

Hi, I'm looking for materials with as high a specific heat as possible that can be used as a heat sink. They have to be safe to use and not extremely hard to obtain. I know I'm being pretty vague, but can anyone help me out.

I was just getting bored so cud someone pls come up with a link or information on how to make a mobile calls interceptor for frequencies upto 900~1200 Mhz??...and the circuit diagram if possible. Help will be apreciated.

Hello, I need your help with an argument I got myslef into. I may be wrong here due to old information but bare with me and see if you can help me out. I am a designer for an engineering firm and I posted a response in a CAD forum in regards to converting inches to cm or mm. Since I did not know what this person was drafting I posted that 1" = 25.3995mm. This was found in an old math book from the 1950's that had a conversion table in the back of it (yes I typed old - I know old sources are never the best thing to quote - my mistake). The industry standard seems to be 1" = 25.4mm and in the link here THIS LINK post's that "1in = 2.54cm (exactly)". I was baffl…

An idea I had some time ago... The idea is reduce energy storaged internally by a loudspeaker - we do this by making it acoustically 'smaller'. The speed of sound in helium is nearly three times that in air at sea level & around 20c [hmmm - need to check that] so this makes the volume of the cabinet act like an acoustic spring through most of the range over which the mid-low driver operates, as standing waves can now only occur at a higher frequency [for a compact enclosure these would cut-in at around 2kHz instead of 700Hz]. This also speeds up the dissemination of energy by the cabinet, reduces reflected sound passing out thru the driver cone, and a host of…

I have two questions and LOTS of time on my hands. How can I make capacitors? How can I make a rechargeable battery? I'm not looking for incredibly efficient, just working. Thanks in advance. P.S.: If you guys have any other ideas about things I could make, along the lines of linear accelleration, power production, etc, lemme know.

I hope this isn't too stupid, but I have to learn somehow. What would happen if you ran a house current back into the house? When you plug in an appliance, current flows through the appliance (like a light bulb) and back into the outlet. What happens if you remove the appliance/resitor from that circuit (keeping the circuit itself intact)? Will current flow? Will it start a fire? Etc.

Hi, My latest project is a spark gap tesla coil. I started to get the first decent streamers a couple of days ago. I thought some of you might be interested . Here's some specs: 4 MOT (Microwave Oven Transformer) Power Supply. Inductive Ballast (limits the current draw to 10A). Secondary Diameter 110mm (1000 turns of 0.55mm wire). Asynchronous Rotary Spark Gap. 80nF MMC Tank Cap (originally bottle caps). It still needs some more tuning, but so far the results are quite nice. I've attached some pictures of it running. Although the pictures never quite capture the full effect. I've got other details and pictures on my website (http://www.craigsarea.c…

I've been toying around and I had an idea. I have a transformer that can supply 26VAC/15A. If I run this through a bridge rectifier, I get about 24VDC (this rectifier drops about 2V). I have two of these handy little rectifiers that can handle 25A at 50PIV max. For my application, I need electricity much as it is supplied with an arc welder, low voltage (about 2V) and high current (the more the better). Here's the question: Hooking two loads to a source of power in series allows the max current to flow whilst splitting the voltage (in the simplest case). What happens when I wire two rectifiers in series? I have confirmed that the voltage is split between t…

I am planning to build a R/c hovercraft starting from scratch......I will try to use total engg approach.....calculating every possible detail...I just wanted a bit help from the rookies...just lil tip about where to start from? Also if u guys know if thers some software available online to compare the theoretical calculations with... any help would be greatly appreciated...! (mech engg student here...so use of technical terminologies will be more than welcome!)

I have been asked to give the formulae and explain using a diagram Bernoulli's equation. I have been told that the equation is: PT = Pst + Pf + Pv +Ph where PT = Total pressure Pst = static pressure Pf = frictional pressure Pv =Velocity pressure Ph = potential pressure I am having trouble as I cannot find this equation in any text. can someone please help.

http://www.energyinnovations.com/ pasadena company, manufacturing in China systems for large flatroof commerical buildings in Arizona and S. Calif. (not for private homes!) $16.5 million venture capital from Mohr-Davidow Ventures (MDV) ----quote from press release---- ENERGY INNOVATIONS SECURES $16.5 MILLION IN VENTURE FINANCING LED BY MOHR DAVIDOW VENTURES PASADENA, CA – June 21, 2005 –Energy Innovations, Inc., currently developing the world’s first low-cost rooftop photovoltaic (PV) solar concentrator system, today announced it received $16.5 million in new venture funding. The round was led by MDV-Mohr Davidow Ventures, based in Menlo Park, CA, w…

I came up with this while cleaning: You know how dust forms in a circle on a t.v. that hasn't been cleaned... well, I am pretty sure this is due to the static electricity. So, I was wondering if I could use place mats (like under lamps) that used static electricity to collect the dust on the surrounding surface thereby elimanting the need to dust. I was thinking you could plug it in or charge it etc. How feasible is this idea and if it is feasible how would you create the static?

The International Technology Roadmap for Semiconductors (ITRS) predicts 9nm linewidth processes by 2016, making it then possible to build complex electronic systems of the order of microns in size. The same roadmap predicts that whilst process linewidth scales by a factor of approximately five the wirebonded I/O pads will only shrink by a factor of two, showing the difficulty in making these connections. Further the transistors that drive these pads will take up significant area on the IC. Such systems may not be purely electronic; so-called smart dust and microrobots might have sensors, micromechanical (MEMS) elements, biomolecules, and use electronics as an interface to…

Well, time for some electronics questions that are so basic you'll think I ride the short-bus to school... Basically, there's a plant I want to grow, and it requires cool water around it's roots. Because I don't have the time to put icecubes on the damn soil all day, I decided that I wanted to find a way too cool it down automaticly. And I found the perfect things: Peltier junctions (apparently also called Thermo-electric coolers), which transform electrical energy into a heat difference across the device, with one side cooling and the other warming up. I can find lots of them, with lots of statistics on them, but here's the problem: Although I took a bit of el…

Hello, I am new here, so hi all again Here goes my question: Why is it unattractive to use a low reaction (having most of the static-pressure rise in the stator) for a single-stage axial-flow cooling fan for electronic equipment? Reasons. Greetings.

Yesterday I saw on the science channel Rutan Space Ship One. Interesting, he is the public private sector. The government will never share there expertise with Rutan. If they do they will control him and his ship. Any thoughts here? pljames

This new invention of the Hidrogen Car seems to be not so good idea. I once tried to do this but i get to realize that the process to get the hidrogen fuel, makes more pollution that the gas or diesel theirselfs, so, whats your opinion?

Could an EMP be used to disable the detonation device of a nuclear missile? Or are simple pressure sensors all that is needed for detonation?

These 2 are the best multirole combat jets i consider of USA and Russia? But... which one is the true best? Or in which specs is one better from the other? I trust in soviet engineering though. I (L) Berkut

I have a technical question about the alternator and the battery charge. When you strart up your vehicle on a low battery, eventually the battery will reach full charge. The charge generated by the alternator recharges the battery. When you have a full battery, however, what happens to the charge that the alternator produces. Is it simply pumped into the fully charged battery or where does it go? Seems like a tremendous inefficiency because performance doesn't seem to be influenced much by battery charge. In all situations, the alternator cranks out charge (irrespective of battery charge and applicance energy draw). Would appreciate it if someone with more experience or m…

Hi, I'm curious whether anyone knows of any software available for the simulation of single electron transistors (SET), or more importantly, circuits composed of SETs. Thanks!

would it be possible to have a giant particle accelerator in orbit around the sun? find a nice, big space(like between some of the farther planets) and have some strategically placed asteroids with powerful magnets orbit the sun. well, could it work?

hey all . At the moment I have a forty dollar gift voucher for a hardware store and my plans are to turn that forty dollars into something more (because Im broke and bored ). I have friends who would buy a case if I could make my ideas come true . I'm intending to build the case from scratch and I just want some advice on a couple things I'm tossing around in my head . Whats the best way of making a mould ? at the moment I'm thinking of just plastering a couple layers of wroughted mesh , any other (easier) alternatives . What kind of polymer is best & cheapest to use in a mould ? Any other advice from people who've attempted this .

I'm taking part in a local water-rocket competition. I was thinking about building a rocker-aeroplane hybrid as the distance rocket. I used a delta wing design(swept-back at 25 degree) with a T-tail. However, my rocket has a tendencency to stall after launch (approx 30m). Further trimming odes not fix this. Does anyone have any ideas? P.S.: I have built a conventional rocket for the distance category in the evnt that this fails or the wind is too strong. (so don't suggest me to build a conventional one: I have already built it) For the duration category, I got problems with the parachute deployment system. the problem is either holding the nose cone stable during …