Direct Generation of a Voltage and Current by Gas Flow Over Carbon Nanotubes
A. K. Sood and Shankar Ghosh
Department of Physics, Indian Institute of Science, Bangalore 560 012, India
published 17 August 2004; PHYSICAL REVIEW LETTERS
Abstract:
We report here a direct generation of measurable voltages and currents when a gas flows over a variety of solids even at the modest speed of a few meters per second. The underlying mechanism is an interesting interplay of Bernoulli’s principle and the Seebeck effect: Pressure differences along streamlines give rise to temperature differences across the sample; these in turn produce the measured voltage. The electrical signal is quadratically dependent on the Mach number M and proportional to the Seebeck coefficient of the solids. Results are presented for doped Si and Ge , single wall and multiwall carbon nanotubes, and graphite. Our results show that gas flow sensors and energy conversion devices can be constructed based on direct generation of electrical signals.
The full paper can be found
here.
This is in continuation with their ongoing reserch on carbon nano tubes. Their
Last paper was taken as a major experimental breakthrough in carbon nano tubes flow sensors and electricity generation and was published in the prestigious
"Science" Journal in its
‘Science Express’ category — one that’s usually reserved for papers having
‘‘timeliness and importance’’.
This one is an extention to demonstrate the phenomenon with common gasses like Oxygen, Nitrogen etc flowing over Semiconductors besides Carbon Nanotubes and generating much larger magnitude of voltage that before.
I'm really glad
business world reported their current work.
TOI is a disappointment for everybody who seeks anything except scantily clad females.
Probability Revisited.
Gokul gave me a nice one some time back ...
If you take two REAL numbers between 0 to 10, what is the probability that the square of one number is greater than the other number ?
By the way...
Probability = No of Favourable Outcomes/ Total No of Outcomes.
Theoretically, both numberator and denominator are infinity. There's a better answer than infinity/infinity though :-)
Inspiration in Conjunctive Normal Form
If--
If you can keep your head when all about you
Are losing theirs and blaming it on you,
If you can trust yourself when all men doubt you,
But make allowance for their doubting too;
If you can wait and not be tired by waiting,
Or being lied about, don't deal in lies,
Or being hated, don't give way to hating,
And yet don't look too good, nor talk too wise:
If you can dream - and not make dreams your master;
If you can think - and not make thoughts your aim;
If you can meet with Triumph and Disaster
And treat those two imposters just the same;
If you can bear to hear the truth you've spoken
Twisted by knaves to make a trap for fools,
Or watch the things you gave your life to, broken,
And stoop and build 'em up with worn-out tools:
If you can make one heap of all your winnings
And risk it on one turn of pitch-and-toss,
And lose, and start again at your beginnings
And never breathe a word about your loss;
If you can force your heart and nerve and sinew
To serve your turn long after they are gone,
And so hold on when there is nothing in you
Except the Will which says to them: "Hold on!"
If you can talk with crowds and keep your virtue,
Or walk with Kings - nor lose the common touch,
If neither foes nor loving friends can hurt you,
If all men count with you, but none too much;
If you can fill the unforgiving minute
With sixty seconds' worth of distance run,
Yours is the Earth and everything that's in it,
And - which is more - you'll be a Man, my son!
View:
'IF' holds the world record as the poem reprinted in more anthologies than any other.Inspiring to say the least.
Counterview:
That should be called Nested-If-O-Mania !
And the PIG Died !
Another puzzle passed on by my insane roomie(offences intended) !
A man has 100 bottles having some liquid. Only 1 among the 100 bottles has poison. He has 100 pigs which he can use for finding out the bottle having poison. A pig dies in 24 hours after it is given poison. The man has to find out in 24 hours which bottle has poison. What is the minimum number of pigs that he requires to use? He can make any combination of the contents of the bottles.
Though I got the correct answer and a theoretically equivallent solution, my roomie was all for his collegue who gave a more elegent solution.
Ok He does talk sense once every thousand years !
A Puzzle out of Another !
I was trawling thru the dustier corners of our old mail server to make sure I dont lose any
important(eh ?) mail if they move it offline !
This is the puzzle I recieved 75+ responses for !!
---
Here it goes ...
A goat is tied by a long rope to one corner of a square house whose sides are 30 metres long. The length of the rope is 60 metres -- long enough to allow the animal to graze over a large part of the property surrounding the house on the back, front and sides. What is the maximum number of square metres of this property can the goat graze?
I was wondering what if the rope's size is incresed to lets say 70 m ? Not as simple as the previous one then.
PS: Assume a greedy goat ;-)
---
The variation in the puzzle(latter part) was just an impulse of thought. But It turned out to be much more interesting than it looked prima facie and probably worth posting :).
