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    Obtaining Oxygen

    But, don't be stupid enough to breathe this, if any peroxide vapor is in the mix, it would be very dangerous for you.
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    West Antarctica's ice sheet loss "appears unstoppable"

    Al Gore should go down there and stop it from moving...
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    Volume Measurement (Dry Method)

    Hi TechFan, Very clever. For the accuracy checks, I would test machined cubes or cylinders with volumes that can be precisely measured. When filling with pressurized air, realize the air temp can be quite different from RT, at least initially. I would add a temp sensor inside to tell...
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    Can I run this with a solar panel?

    And of course, if your solar panel is not pointed directly at the sun, preferably in the middle of a sunny day, it will give you less power than it is rated for...
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    Making a pressure cooker from scratch - need help with equations

    Tobias, What you said: 'and couldn't find anyone engaging in a similar project.', should be a major clue for you... I'd recommend you Google 'Darwin awards', a group you don't wish to join...
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    Making a pressure cooker from scratch - need help with equations

    Tobias, You have chosen a question that is not likely to get answered by anyone who knows better, since no one would want to see you kill yourself or others. Bottom line, pressure vessel design is not for amateurs (and is guaranteed to cost more than a commercial device, even for someone...
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    Alternate shapes for compressed cylinders

    Because for the vast majority of applications, weight and/or cost is also a prime factor. Cost is related to the amount of material used in the tank and its processing cost. The lowest weight format for any pressure vessel is a sphere, which is why these are used in weight sensitive aircraft...
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    What would be the best method for heating copper tubing via nichrome?

    Note also that the nichrome will expand when heated and may not stay tight on the ceramic paper....
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    Heating 800 watts nichrome wire with a battery.

    There is no fixed value of 'temperature' given the specification of a "800W Nichrome wire". A stable temperature is achieved once power in (800W, assuming you set the voltage correctly) equals power out (heat flow). So, the answer depends on what is surrounding the wire (vacuum, still air...
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    What would be the best method for heating copper tubing via nichrome?

    I'd probably get some ceramic paper or thin ceramic cloth and wrap the Cu tube with it, then wrap nichrome around both with many turns. I would then wrap this with many layers of ceramic paper or cloth and keep it all together with standard steel wire twisted upon itself. The nichrome...
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    Good thermal conductor but insulator

    You might also consider simple hard anodized aluminum. The anodized layers should give you a thick enough oxide to prevent any electrical conduction. Of course, anything contacting it should not be able to break through this oxide layer.
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    Astronomy Day is coming at my university; any suggestions for demos?

    If you can find a rubber sheet, say 3' x 3' and stretch it evenly on a rigid frame, then put a weight in the middle to simulate a massive object (say the sun), you can show a model of space-time and explain how the models dimple makes smaller objects orbit the central object. This would be an...
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    Good thermal conductor but insulator

    First throught was diamond, but 'easy' to fabricate rules that out. Second thought is BeO ceramic, but must be processed very carefully to prevent Be poisoning. You may want to research thermally conductive ceramics - there may be some that are not dangerous to process. There are some...
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    Chemical for cleaning printed picture on plastic material?

    Sorry, I have no recommendations specifically for 'ink'.
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    Chemical for cleaning printed picture on plastic material?

    You'd need to experiment - the items I've mentioned are known to be non-toxic. There are many toxic options, but you would be risking the health of the personnel. If you want to go the ultrasonic route, best to contact the companies who sell these units and ask for their recommendations...
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    Chemical for cleaning printed picture on plastic material?

    Hi David, Best to do some testing with samples that you don't care about ruining. Start with warm water, then perhaps with a little soap added (try Dawn or equivalent). If that doesn't work, I'd try Isopropyl Alcohol. A lot depends on what material you are trying to remove from the...
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    Plate thickness

    Use a caliper if it already exists. Or, is this a homework type problem to calculate the minimum t to hold the 17kg? If you just want to make something, use 1/4" alum.
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    Strength and weight of materials

    Let's say you have a piece of Aluminum 6061-T6, with cross section 1" x 1" (length does not matter). This alloy has a tensile (yield) strength of about 40,000 psi. This means you'd need to tie one end vertically to a rigid beam, and hang 40,000 pounds on the other end to barely deform this...
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    Stability of quarks

    Are there any good theories why neutrons in *most* nucleii are somehow stabilized against beta decay, whereas free neutrons have a known half-life? I'd like something better than 'it's all due to the weak force'... Also, would the light quarks theoretically be stable in their free form?
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    What is this material?

    Galinstan is a nontoxic alternative for Mercury in thermometers. These are generally not compatible with aluminum, but you'll need to do some research to see what metals they are compatible with. I would not attempt any electroplating - simply get tubes of compatible metals of the correct...
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    Engineering What can I do with Chemical engineering?

    You can feel good about yourself by finding things that are *less* damaging to the environment, without necessarily finding things that are completely benign (though that's the best outcome)... Replacing some current extremely toxic compounds with some slightly toxic would be good trade IMHO.
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    What is this material?
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    Reprocessed Uranium

    Appreciate the clarification :-} Was thinking mostly of the French...
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    Reprocessed Uranium

    Purely political - mostly by those who oppose nuclear power. This lack of US reprocessing gives an artificial argument against nuclear power (where do we store the waste???), while solving the problem removes this 'issue'. Other countries reprocess in a very safe way.
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    Pu from spent fuels can't be used for weapons?

    I suppose you can chemically isolate the Pu, then subject it to isotope enrichment as is done with natural U, but it would be a terribly radioactive process. Easier to just remove the fuel after slight burn-up to limit the amount of Pu240. If you can guarantee a suspect country would not...
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    Electromagnet directly connected to power supply not working

    Check the amp rating (I) on the charger (likely 1A or 2A). At 5V output, the resistance R it could handle is 5/I (remember V=I*R ? ). Your wire must have a resistance R the same or greater than this. Your R will be r per foot * (length in feet). Ignore the inductance for this. Make...
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    Dummy Load Selection

    The only way to make a 'smaller' 2.5W rated resistor is to dramatically increase either the airflow across it (forced airflow), or some form of liquid cooling, direct or through a metal interface. Heatpipes would also transfer the heat elsewhere, but I doubt that's what you're after. The...
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    My AA batteries short circuited, ruined?

    Looks like a D-cell can do about 1A max, so your 6V charger should be able to do this also. Going to 1.5A or 2.0A would not hurt if that's what you have. Obviously, if you modify the power...
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    Wormholes with a different gravitational potential at each end

    I tend to dismiss the entire concept of 'wormholes', until and if they are found or created. Just because something appears to be possible mathmatically (with all the assumptions and approximations inherent in the math equations), doesn't make it necessarily physically possible. Therefore...