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  1. C

    Why are gas turbine engines not used in automobiles?

    barring a few exceptions i read that it is because they aren't effecient at small scale. can someone elaborate on that? also, would even smaller turbines need some time to start up?
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    Are phosphor sheets used in CRTs transparent?

    and if they are, to what extent?
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    Piston seals

    as far as i understand, piston have cast iron seals because of the properties of cast iron, which make it a sealing material. but i was wondering, if the cylinder and piston are both made of cast iron and closely fitted together, could we avoid using seals all together? friction doesn't depend...
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    How is a wankel engine lubricated?

    i was admiring its animation like when this popped into my head. any answers? also anybody know any latest developments in lubricating closed off engines?
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    Rotary atkinson cycle engine

    http://white-smoke.wetpaint.com/page/Rotary+Engine [Broken] does anyone know of this engine being used in production?
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    Rotary vane engines

    are the 'vanes' of a rotary vane engine a major disadvantage? granted that the vanes would be under considerable stress, but is it so much larger than the stress on connecting rod in reciprocating engines? and is sliding friction on sides very high compared to pistons? also, is sealing a major...
  7. C

    More efficient compressor

    given the same volume and rate of air flow, which would be more efficient compressor between a rotary vane compressor and a bellow?
  8. C

    Medical What's the difference

    what's the difference............ ...................between amphetamine and methamphetamine, effect wise?
  9. C

    Is 59,649,589,127,497,217 a prime no.?

    scratch that. is 5606701775893 a prime number?
  10. C

    I have no knowledge of number theory

    hi, i have only basic knowledge of number theory, but would like to know a hell lot, like maths major level or something(especially about fractals). is there any good site where i could? and please don't suggest wikipedia.
  11. C

    Penguins in new zealand?

    alright, i just read about the 'yellow eyed penguin' that lives in new zealand, and i am wondering how it is possible? how can two genes of same species develop on opposite corners of the world? were new zealand and antartica next to each other in pangea?
  12. C

    Why not just collide particles for fusion?

    why do scientist insist on confinement as the way of producing power, not something like colliding accelerated particles together? and is polywell really the best possible method to produce fuion power as the new trend suggests?
  13. C

    No of blade sets in reaction turbines

    why do we need to have many sets of blades to utilize the gas pressure in reaction turbines properly? why not have just a set of comparatively wider blades?
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    Medical Caffeine and nicotine

    do caffeine and nicotine have the same on the brain? if not, how do they differ?
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    Nanotubes from exhausts?

    i read about this project for making carbon nanotubes from industry exhausts. is this possible/viable? if so, how economical is it? has there ever been any previous work in this area?
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    How to file for a us patent?

    does one have to be a us national to get a us patent? also could anyone enlighten me on what patent cooperation treaty is? thanx
  17. C

    What does exactly constitute plagiarism?

    just what i meant by the question. for example if a bloke wrote a paper on an innovative way to use web technology and another bloke used that paper to sell a product, does it amount to plagiarism or does the new method have to be patented first? im not sure this should be posted in general...
  18. C

    Crankshaft lubrication

    as i have seen, usually in ic engines, the oil is forced into the journal bearings and then it travels along passages in the shaft to connecting rod bearings. but how, does it enter the passages in main bearings with so much centrifugal force. if i understand correctly, the cetrifugal force is...
  19. C

    Murphy's law of thread notification

    why is it that you post on 'pf random thoughts' once and get notifications for eternity but have to keep on checking 'best guitarist ever' for new posts?
  20. C

    Am i the only one who finds this scary?

    http://inhabitat.com/2010/04/30/hydro-lance-recycles-jets-into-high-speed-planeboats/
  21. C

    Average flow rate of water?

    what is the average flow rate of water in the water jackets in an ic engine?
  22. C

    Ic engines temperatures

    can someone tell me what temperatures ic engines generally operate at?
  23. C

    How thick should the walls be?

    if there is a hollow cylinderical hole with maximum internal pressure P in a hollow casing which is likw a cylindrical shell, how do we get how thick the walls will be?
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    Variation of specific heat with temperature

    how does specific heat of gases vary with temperature? is there an equation to describe it?
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    Specific heat of petrol air

    what are the Cp and Cv values of petrol and air?
  26. C

    Ratio of air and fuel in SI

    what is the average air to fuel ratio in spark ignition engines?
  27. C

    This isn't trivial

    this might seem trivial but i have no thermo books on hand and i can't remember what we call those properties whose value depends only on initial and final states of gas but not on the process adopted to reach final state?
  28. C

    Should i take ai as elective?

    i am be computer science third year. i love discrete mathematics and am being told that ai is pretty much algorithms as maths. so should i take it as an elective?
  29. C

    Efficiency of compressors

    for a given volume of gas,is it more efficient to compress smaller volumes of gas more no. of times or compress large volumes of gas less no. of times?
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