&--Sunday, September 30, 2007 ; 6:48 PM
EldwinSchrodinger @ Mini Earth created in the lab
EldwinSchrodinger @ Mini Earth created in the lab
loving you always ♥
Physicists have reproduced the fluid dynamo mechanism that produces the Earth's magnetic field in a laboratory experiment for the first time. Electric currents produced by the circulation of the molten iron and nickel that surround the Earth's core are thought to create the Earth's magnetic field. Now physicists from Latvia and Germany have measured magnetic fields produced in liquid metal in a special facility at Riga, Latvia. The fields match the predictions of fluid dynamo theory (Phys Rev. Lett. 84 4365).
A conducting fluid needs to have a small 'seed' magnetic field before it can generate a self- sustaining field. The seed field induces electric currents in the fluid that in turn create a more powerful, and stable, magnetic field. This creation of the field relies on a positive feedback mechanism. However, the process only works if the metallic fluid is moving very quickly or if it exists in very large quantities.
The Latvian-German team applied a small magnetic field to a container filled with two cubic metres of molten sodium that was rotating at 15 metres per second. The high conductivity and velocity of liquid sodium was fast enough to generate an oscillating magnetic field in the fluid, and this field was maintained when the external magnetic field was turned off.
Labels: Technology
&--Thursday, June 21, 2007 ; 1:14 PM
EldwinSchrodinger @ Sky Elevators.
EldwinSchrodinger @ Sky Elevators.
loving you always ♥
Heard of them? in games, movies etc? if not now you will. if humans were have to travel back and fourth to space with shutters. wouldn't it be rather costly per trip and fuel wastage? with this idea and our current technology its feasible! firstly in recent development of nano technology brings us this very strong micro cables known as carbon nanotube. some of you would wonder. what it is? now here's how it'll look like.
i can say. these guys are strong. and stronger than steel which of course, capable of spanning miles from land to space. the problem is. how to join these nanotubes together to form a 4000mile long cable? now thats the question we scientist would like to find out. =X
but there's something which is bugging me the whole time. how could a nanotube support such great tension at such great heights? furthermore supporting a space station up in space which literally "hangs" from earth's ground. and what device is capable to "holding" the sky elevator in place?
now there setbacks about a space elevator. its vulnerable to bad weather and strong winds. you wont want to stay in a capsule swinging back and fourth wouldn't you? secondly. what if the cable snaps and THAT would be disastrous. now for the good points. its very easy to use and its energy efficient. so If space elevator indeed become a reality, sky elevator can be the easy connection point from the earth to space.
Labels: Technology
&--Friday, March 16, 2007 ; 12:45 PM
EldwinSchrodinger @ capacitors
EldwinSchrodinger @ capacitors
loving you always ♥
Capacitors. Capacitors are the most widely used power source for energy discharge experiments: From Z-pinch driven nuclear fusion to lasers, rail guns, coil guns, EMP generators and hypersonic metal forming, capacitors provide the ultra fast, extremely high power impulses required to achieve the currents to drive the enormous magnetic field these devices require. Although high performance high voltage pulse capacitors are extremely expensive, costing several thousand dollars per kilojoules, the (relatively) lower current requirements of coil guns make it possible for non pulse rated capacitors to be used on them with good results. Amongst the worst capacitors in terms of pulse performance are electrochemical capacitors (these are also very low voltage, thus being unpractical on coil guns) and electrolytic capacitors. However, electrolytic capacitors also happen to be the cheapest capacitors around, so it is not surprising that just about amateur every coil gun uses. Electrolytic capacitors come in many types: Computer grade, inverter grade, and pulse rated. Pulse Rated electrolytic capacitors include those used in camera flashes, and those I use on my multi stage coilgun. They differ from regular electrolytics by making use of thicker aluminium plates and stronger internal connections. The larger ones also have much bigger terminals, which are a direct indication of their intended high peak current. These capacitors are the perfect compromise between price, energy density and performance on a coilgun: They cost less than pulse capacitors and are lighter for the same energy storage, and their performance is only slightly below what a real pulse cap can achieve. Photo Flash capacitors also work well, though the smaller units require so many connections that a lot of resistance builds up on larger banks. Inverter grade capacitors are reasonable since they are made to operate at higher RMS currents and duty cycles than regular electrolytics; the computer grade capacitors. Even the worst electrolytic capacitors can be made to work in a coilgun, provided, as was said in the beginning of this tutorial, that they are of high enough voltage. 450V peak capacitors and 550V peak capacitors are the best ones because they do not require excessive series connection; because they have a very high ESR (Equivalent Series Resistance), electrolytic capacitors should not be placed in series for pulse applications because the ESR of the bank can very quickly become larger than the impedance of the load, and if that happens most of the energy of the discharge will be dissipated internally, damaging the capacitors. With pulse rated electrolytics it is possible to place some in series and thus obtain performance gains. My current systems operate at 900V, though even higher voltages would be desirable. The most efficient coilgun ever developed was fired at 3,5kV per stage.
more cool stuff can be found here
http://www.powerlabs.org/coilguns.htm
http://www.rollette.com/railgun/
Labels: Technology
