# Search results

1. ### Sunlight Intensity Concentrator - Idea to boost solar energy

OK i see what I did wrong in my math, your right 1300 W/m^2
2. ### Sunlight Intensity Concentrator - Idea to boost solar energy

Where's this figure from?
3. ### Sunlight Intensity Concentrator - Idea to boost solar energy

I never did say anything about a mirror, I don't know where that idea originated. I'm thinking more along the lines of capturing the energy of the expanding sphere of sunlight before it dissipates to much. If you imagine the wavefronts of my drawing in 3-D you see how the closer we get the more...
4. ### Sunlight Intensity Concentrator - Idea to boost solar energy

I'm not saying we have to harvest every last bit of power the sun gives off, just a 100 sq meter portion of it. As for frying cities, would there not be a way to have a satellite closer to earth, splitting the energy up to a few other satellites and so on until it is reasonable to shot the power...
5. ### Sunlight Intensity Concentrator - Idea to boost solar energy

So I had this idea and I want to run it by some people and see if it's 1) possible 2) worthy of pursuing further 3) a good idea. I don't have a degree in engineering or physics, I'm currently studying chemistry and am taking physics 2 (E&M) right now, so excuse me if I don't use the correct...
6. ### Where is the alcohol peak on 5-iodovanillin?

Well I posted on another forum and they said that it is probably to to rapid exchange of the phenolic proton on there. Makes sense because I used acetone and ketones have a lower pka value than phenols. So yes it is solved. Thanks tho
7. ### Kinetic friction and lost mechanical energy

Ok so there is no ratio. I think your getting force and energy confused also. Be aware that force has units of Newtons= kg*m/s^2 and energy has units of Joules= N*m= kg*m^2/s^2. The mechanical energy lost is equal to the thermal energy generated. So if T is thermal energy then using conservation...
8. ### Schools Local university doesn't offer physics major

Where is this university? I want to go to school for free! All I can say is I'm a sophomore in chemistry right now and I study physics probably 10 hours a weeks, chemistry another 10 hours a week plus other classes (about 3 hours for each hour in class). But I believe I'm more motivated that the...
9. ### Kinetic friction and lost mechanical energy

I agree with you that u= tan(theta). As for the ratio- the ratio of mechanical energy lost to what? Thermal energy maybe?
10. ### Where is the alcohol peak on 5-iodovanillin?

So I'm pretty sure I got 5-iodovanillin. The melting point in the literature is 183-185 C and I got 182.7-183.5 C. But my NMR spectrum isn't showing the alcohol peak. It barely shows up on the SDBS spectrum also (http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi). Does anybody know why...
11. ### Hybridization of carbanion in rings

ok I can see it now that was very helpful, so if you draw the resonance structures and they end up looking the same but rotated, is that a way you can tell they are especially stable? Does this theory have anything in common with VSEPR? My book only mentions VSEPR and nothing about valence...
12. ### Hybridization of carbanion in rings

So this question asked me to determine whether this compound was aromatic, antiaromatic, or nonaromatic and also asked how many pi electrons there were. I figure since there are four groups of electrons the carbanion is sp3 hybridized and I think I'm correct because that is what this thread...
13. ### Polarization of an Insulator

OK so what your saying is the electrons still do move, but only within the atom or molecule?
14. ### Polarization of an Insulator

So I just started Physics 2 Electricity and Magnetism and I'm already scared for my life. The professor first did a demonstration where he charged up a Teflon rod on some sort of cloth and moved an aluminium can with the rod. I understand how that happens. The can is a metal and conductor so the...
15. ### Dehydration / demoisturization

I've used perlite in the past to get food nice and crispy. But make sure you don't let the food come in contact with the perlite, might be dangerous, I'm not sure.
16. ### Is a Satellite free falling?

Have you ever herd of the thought experiment with the bullet going faster and faster? Imagine firing a gun. The bullet goes really far but hits the ground eventually. If you could make a super powerful gun that fires the bullet really fast, the bullet would still be falling toward the ground...
17. ### BP and MP of Caffeine

OK, you think they would put the pressure they measure at if it wasn't at 1 atm.
18. ### BP and MP of Caffeine

Pubchem says the BP of caffine is 178 deg C (sublimes) and the melting point is 236.2 deg C. Below is the only phase diagram I found for caffeine. Aren't the MP and BP measured at 1 atm? If so according to this phase diagram it shouldn't sublimate correct? Assuming the phase diagram is wrong...
19. ### Schools Enlistment is ending, seeking advise on applying to universitys

Hello PF members, I'm a 21 year old combat engineer in the marine corps. My 4 year contract is about to end next July and I want to start preparing myself for undergrad school. I've already started the application process (for fall of 2013), but some of it's confusing. It asks for high school...
20. ### Concentrated Photovoltaics, Parabolic Mirrors

thanks for all the replies, looks like I got a lot to learn.
21. ### Concentrated Photovoltaics, Parabolic Mirrors

I don't see any issues, other than what Enthalpy said, but I don't know much about electricity. I understand what leakage current is, but can't make sense of reverse leakage current.
22. ### Concentrated Photovoltaics, Parabolic Mirrors

The idea of a parabolic mirror to focus light onto a small solar panel popped into my mind the other day. I searched Google and this is about the best thing I found- http://www.greenrhinoenergy.com/solar/technologies/pv_concentration.php and...
23. ### Military and then education?

Hello Power Biggs, I joined the military right after high school and will be pursing higher education when I get out next year. There are many opportunities to get an education while in the US military, for example TA which provides you \$4,500 a year for college and of course you have the GI...