I realize that going from tens of nm to a few nm is a huge leap. As I understand the biggest hurdle in my concept would be to transfer enough gaseous substrate through such a tiny pore. As I heard about ballistic, extremely efficient transport of water molecules in carbon nanotubes of certain...
Thanks for your suggestions.
Nevertheless, I can imagine that first the catalyst would be deposited on the entire surface of the membrane, and next deposition with an inert layer of some kind would cover it, to inhibit carbon film formation. Nanoholes could be cleared by passing a reactive gas...
Would it be feasible to synthesize carbon nanotubes from a carbon gas source that had passed through a man crafted nanopores (nanoholes, nanochannels), the outflowing end of which is covered with a catalyst? This artificial membrane would separate gas source chamber from a product chamber...
@Henryk Thank you for answering. But I do not understand your point. Isn't it that lens are doing just that: squeezing radiant power into a smaller area?
@berkeman Thanks for your time. Yes, I think I get it. With shrinking the pathway, light rays approach to being perpendicular to fiber walls. I guess that after passing the acceptance angle of the fiber, they will be dispersed. Right?
I am ignorant about laser physics, but i have this idea of collimating monochromatic light with an optical fiber/cable that is cone shaped: at inlet the cone has a wide diameter (several hundred microns - like an ordinary optical fiber, which might be used as a light source), on the other end it...
After 4 pages of posts, I will try to recapitulate what I understood. I will use as simple and widely understood laws of physics as possible.
1. spaceship is propelled with constant drive power: P. That's because
2. it uses constant mass of propellant per second: mp
3. which has final velocity...
The thing that I learned most from this thread is that it seems one can't talk about power, force, etc. generally but only in specified context (as Gerenuk underlined).
Thank you K^2 and all you people for your effort. You've helped me a lot!
Ok. So I understand (after small tutorial from wikipedia) that p is photons momentum and P=.5*c*mass*g. Thus finally I've got confirmed that Power is linearly dependent on Force... ;-). Just joking. I understand that it holds only for this specific experiment.
Ooops, you're right - that makes 5,3 kW.
Obviously, that's why I have cut the text out, but you were faster :)
Then, what constrains engineers from making much bigger rotors, as it'd reduce power, i.e. energy consumption for hover flight - blades' mass and strength? New lighter...
Ok, last defense line of my wicked intuition:
what if a saucer is kept hovering in a gravitational field by an external, constant power laser from the ground. We have both const. power & force. How would you calculate power, given the force?
After reading all the posts, I am leaning...
Ok, last defense line of my wicked intuition:
what if a saucer is kept hovering in a gravitational field by an external, constant power laser from the ground. We have both const. power & force. How would you calculate power, given the force?
After reading all the posts, I am leaning...
K^2, I went through your helicopter formulas - as an ignoramus in physics I am impressed, though not totally convinced.
It seems from your
P = \frac{1}{2} \frac{(Mg)^{\frac{3}{2}}}{\sqrt{A\rho}}
that by simply increasing disc area A one can easily decrease required power...