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Physics, Astronomy & Cosmology / Would a Mylar sheet with holes to allow some heat to pass prevent over-heating?

« on: 21/10/2016 06:51:22 »

I have heard mylar blankets can trap some 90% of your body heat. The issue being, they're so good at it, they can also cause overheating, and I understand this as the reason we don't see the material used more widely than it already is. This made me wonder, however.

Could you poke minuscule holes in the mylar, so that it only traps 85%, or 70%, or 50% of the heat? Then, perhaps, you could have overlapping layers of mylar, and a simple adjustment could let you control this?

I expect this is a stupid question, and I apologize. I don't know much about how heat radiates. The issue I see with this idea is that, say the air was at -30C, traces of that could get through the tiny holes so that it's not a matter of 50% of the heat escaping, but of 50% of your heat escaping and cold air absorbing heat as well.


If someone could please help me to understand this, I would appreciate it. Thank you.

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Chemistry / Could Vulcanized Rubber be Invented with Primitive Technology?

« on: 17/10/2016 21:48:08 »

I have question related to my writing. I apologize if this is considered too speculative.

My question is how technically possible it would be for ancient people to invent vulcanized rubber. From what I've heard, formic acid is necessary to prepare the rubber before sulfur can be added. I'm not sure how John Ray isolated it from ants, and his method might have only been possible by the 17th century.

Normal non-vulcanized rubber has been around since early times, so that aspect is easily arranged.

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Chemistry / Could Mussel Byssus be Processed into a Rubber-Like Material?

« on: 17/10/2016 21:04:06 »

I was wondering if mussel byssus might be able to be processed into a rubber-like material. I'm not sure if Chemistry is the right area for this post, and I hope it is not too speculative.

I was interested in a rubber-like material which may be resistant to temperature and saltwater, and wondered if this might be a good ingredient.


Thank you for considering this question.

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Technology / Can an Electro-Laser use AC (Alternating Current)?

« on: 24/07/2016 13:10:10 »

You know those electro lasers the military was working on a few years ago? They ionize a plasma channel through the air with a laser, then send electricity through the plasma like a wire. I was curious if you could get AC working with such a system, or if it has to be strictly DC.

I'm sorry if this should be obvious to me. Please forgive my ignorance.

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Technology / How do you Calculate the Effectiveness of a Faraday Cage?

« on: 24/07/2016 13:06:32 »

In short: I'm wondering how many watts (approximately) of energy it takes, for charge to break through a Faraday cage. Specifically with aircraft. Whether it would be tens, or hundreds, or even thousands.

This is more direct than my other questions. I want to work out how effective a Faraday cage UAVs and other aircraft have. More specifically, how much charge you need to hit them with till you can get through the Faraday cage.

Microwave jammers capable of messing with aircraft have been gaining interest lately.

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Physics, Astronomy & Cosmology / Which Electromagnetic Wave Builds Electric Charge (in Metal) the Fastest?

« on: 20/07/2016 09:15:53 »

Forks in microwave ovens are known to spark. However, as far as I've heard, laser in the infrared and visible light spectrum don't build much or any charge on metal. I was curious about which electromagnetic wave builds charge the fastest/most efficiently. I expect one of the ionizing types of radiation?

PS: I assume that this only happens with metal, but for all I know some EMW might build a charge in other things.

Thank you for your help.

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Technology / How Powerful a Microwave would you need for an Effective Weapon?

« on: 19/07/2016 04:30:12 »

I am trying to estimate an effective range and power for a microwave weapon for a story. The idea is mainly something that short circuits electronics, and microwave radiation fields that ionize any missiles that come near. That, combined with a large spark coil, is intended to fry anything that gets near the radiation field, making an automatic point-defence system.

The question is, how powerful would this need to be? Initial estimates are at a 10kw microwave emitter, probably at the same frequency as a microwave oven. I'm not sure of exact wavelength, as I haven't been able to find good charts on attenuation lengths in air and other mediums.

I'm sorry if this question is not suitable for this board, I wasn't sure where or how I should put it. Thank you for any advice you can give.