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JKMSMKJ said...on 'Reverse Osmosis':
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The 'crazy' and 'semi-' joke reminds me of this article (blogpost) which argues 'Most Crackpots are Engineers!'! And also a remark by Prof. Likharev in one of our Stat Mech course: "When Engineers try to do Fundamental Physics, the Results are usually Pathetic."
I wonder if you have also come across such people, quacks I mean... :) ;May 20, 2010 6:44 AM
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Frankly, no!
My interactions with Engineers at IIT KGP were minimal.
The fault was entirely mine. Shy and unsocial, all the time sitting alone under the Mango tree at the Co-Op Canteen or under the Neem tree at Harry's, with a cup of tea, woolgathering.
But, Prof. Amalendu Mukherjee (ME) tunneled through my repulsive barrier early on and we had nice discussions whenever we met. He was too good at Physics to dabble in it frivolously. And he was too busy developing 'Bond Graphs' for which he won international fame. He knows Physics like the back of his hand. But that's about it. Somehow he found in me a patient listener (as long as I am not asked to talk!). At Harry's I introduced him to our new recruit, I think, AT: "Meet Amalendu; 'a lion in sheep's clothing'. He can rip anyone apart if they talk wrong Physics fundamentals".
A very learned Professor, interested in the best things of life, like music, arts, philosophy etc. We met briefly this January at KGP and he recalled how I published a Paper with his son, Abhro, when he was in Class XII, a different story!
Professor Swapan Mazumdar of CE was also very knowledgeable of Physics but our interactions were brief but enjoyable.
Professor R. N. Banerjee of IEM was a student of B. Sc (Hons) Physics at IIT KGP, but shifted to ME and then IEM. But he is a turn-coat Engineer, always a Physicist at heart; so he doesn't count!
I had a fruitful interaction with Professors of IEM that led somewhat undeservedly to a paper for me in IJPR, with the present Director, Professor D. Acharya, 20 years ago, when we were all relatively KIDS! Talk of Inter-Disciplinary Research!
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Composite stage effects in unbalancing of series production systems
Authors: A. Mishra a; D. Acharya a; N. P. Rao a;G. P. Sastry ab
a Department of Industrial Engineering and Management,, Indian Institute of Technology, Kharagpur, India,
b Department of Physics, Indian Institute of Technology, Kharagpur, India
International Journal of Production Research, Volume 23, Issue 1 January 1985 , pages 1 - 20
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But my problems were with Chemistry.
Now, I respect Chemistry wholeheartedly. Everything started with atoms and molecules. Chemists are down-to-earth. They HAVE to dabble in things that matter. They are practical. They can't take recourse to idealizations like we Physics chaps do. We are happy to get the unphysical 13.6 eV for the ideal Hydrogen atom. They have to get the energy levels of the real Hydrogen Molecule. We give up! No exact solution. They have to take recourse to all sorts of approximations and GET it close to the experimental value. Not easy!
My troubles with Chemistry started with my foray into my son's Class XI Chemistry Book. As expected,they start with the Periodic Table. And at once QM starts in its most difficult form. s,p,d,f, etc and Molecular Orbitals and the like.
But the Indian text books are sloppy.
They get the energy E of the photon emitted by the electron jumping from the first excited state to the ground state of the H atom ok. Then they equate E = mc*2, and get the mass of that photon! When I say photon is massless, they are offended.
I gave up.
But B Tech First Year students read Chemistry before they read Physics. And ask their Chemistry teachers all sorts of funny questions.
Only Prof SR of Chemistry penetrated my Repulsive Barrier and asked two such 'weird QM questions' and I am happy that I could satisfy him at the Harry's.
Q1: "When an electron jumps from a higher Bohr orbit to a lower one, what distance does it cover? In what time? With what speed? Does it exceed the speed of light? Does it not violate Relativity?"
[A perfectly legitimate question flowing from the Bohr Orbit Diagrams, and 'Electron Jumps']
My Answer: "Don't think of the electron as a 'bird' jumping from an upper branch to a lower branch. Think of it as a monkey swinging between the two branches before letting the upper one 'go' and settling on the lower one. It swings with the Bohr Frequency. The monkey is charged with static electricity (like the electron). Its tail acts as an antenna. So, it radiates EM Waves like any antenna. The frequency of the wavelet emitted corresponds to the frequency of the monkey's oscillations. It swings for a time equal to the 'lifetime' of the excited state. The photon emitted has the frequency of the monkey's oscillations. The lifetime of the 'emitted wave packet' (photon) is the same as the lifetime of the swing. The emitted photon wave packet travels with the group velocity of light.
Q2: "What is the example of a 'Particle in a Box' in Chemistry? What happens if the walls of the Box move to and fro?"
My Answer: "Two protons forming a Hydrogen Molecule Ion is the best Chemical example. Protons are the walls. The electron shuttling between the two and bonding them is a 'Particle in the Box'.
In your simple model, the protons are at rest. But in practice they 'vibrate'. This is the model of a 'Particle in a Box with oscillating walls'. You have to solve it using the Born-Oppenheimer Approximation in Molecular Spectroscopy and get the vibration-rotation-electronic level diagrams'
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Apparently Prof SR is pleased. But I WAS more pleased than him. Bravo, Harry's Chai!
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As I told you earlier, we fought with the then Director, Prof. KLC in 1990 or so and won the rights to teach QM to all B Tech Students in their Second Year.
But how?
There were six Sections. And we were six newly promoted Professors, asking for it. So, we had to teach the six Sections.
But our backgrounds and interests were different: Professors: STA (Nuclear Physics),SB (X-Ray Crystallography, AVK: (Spectroscopy), NKM (X-Ray Diffraction), DB (Particle Physics & Group Theory), GPS (General Physician & Surgeon).
We met and decided that we will have only the Mid-Term and End-Term Question Papers and the Tutorial Sheets common.
Otherwise, everyone will teach as they like.
Result: No two sections had the same Lecture Notes. DB wanted to take the most 'talented and interested' section: ECE & CSE; so he can teach all his math tricks. I wanted to take the most rowdy but intelligent section: CH E. Challenging to keep them awake. No math at all as far as possible. Hand-waving pure gul!
Others chose other sections.
It was like the Elephant (QM) and the six blind Professors. One would touch the trunk, the other the ears, the next the tusks, another the tail, last but one the feet, and the junior-most me the teat!
[Readers Digest Joke# 1: Mam trying to teach the KG Class the difference between bipeds and quadrupeds by example: "What is it that the cow has four and I have two?"
Smart kid: "Teat?"
Now that we are on the subject of animals:
Readers Digest Joke# 2: The Selection Committee of the Navy intent on taking the cadet in because of his wonderful Physicals. But the chap is dumb. So, ask the simplest possible question;
Q: "Name two grass-eating animals".
No answer.
Baffled, repeat question; "Can't you name two animals that eat grass?"
"Sorry, but I heard: 'two admirals'"]
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Another example of Dr Dracula:
One noon, Prof VS entered my Room and said he wanted help. Apparently, a 3rd Year stubborn student (AVM) challenged his low-marking for the QM question on Hydrogen atom. I asked VS to show me the script. The question was if an electron in a non-central potential can have its Schrodinger Equation separable. The book answer is: 'No'. AVM said, 'Maybe'. But couldn't give a counter-example.
I asked VS to send AVM to me.
AVM met me that afternoon and agreed with the marking because he couldn't give the needed example.
He left satisfied apparently.
But that set me thinking. Him too.
By next morning, he came and showed that it IS separable in the non-central Electric Dipole Potential. I showed him my own overnight calculation. Both matched.
We agreed to go ahead and solve the Schrodinger Equation for the electron in a dipole potential.
I first tried the classical motion and showed him that a cone exists on which 'closed orbits' are possible. In our next meeting, both of us agreed that all closed orbits have the same Energy: 'Exactly Zero'.
We tackled, with VS, the QM equation. Stuck up with solving the Radial Equation. No solutions by the 'series' method or any other method. DB concured.
Left it at that and AVM went to Princeton.
Two years later while sipping Chai at Harry's, I realized that no solutions SHOULD be there. Reason: 'Bertrand's Theorem'. The 'orbits' have to be unstable. Indeed they are 'knife-edge' orbits.
In a couple of days, the classical Cone emerged from the QM Radial Equations with the help of the Sommerfeld(again!)- Wislon Rules.
Energy exactly zero for all solutions (orbits), but possible dipole moments quantized!
Problem solved in toto, and published:
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Bound' states of an electron in the far-field of a polar molecule
Author: G P Sastry , V Srinivas and A V Madhav
Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721 302, India
European Journal of Physics
Volume 17, Number 5, Page: 275, 1996
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Just now I saw our paper cited, as a Problem given out to Princeton Students:
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[PDF]
Motion of a Point Charge near an Electric Dipole 1 Problem 2 Solution
by KT McDonald - Related articles:
[4] G.P. Sastry, V. Srinivas and A.V. Madhav, 'Bound' states of an electron in the far-field of a polar molecule, Eur. J. Phys. 17, 275-278 (1996), ...
www.physics.princeton.edu/~mcdonald/examples/dipole.pdf - Similar
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Long Live Woolgathering at Harry's!
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Now that this blogpost has both Elephants and Monkeys, let me sum it up with another joke told by Abdul Mazeed (of the Three Cheers' Fame):
[Joke # 3: Mr and Mrs Monkey were watching a herd of elephants passing by under their tree.
A beautiful young 'maiden-elephant' stood for a while under the tree.
Mr Monkey at once fell for her beauty and jumped upon her.
And started making Love.
Mrs Monkey got jealous and picked up a huge coconut and flung it on the 'maiden-elephant's head.
It winced.
Mr. Monkey: "Oh, sorry! Did I hurt you?"]
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