infinity

Angular Distribution of Diffraction Orders in Diffraction Grating

noreply@blogger.com (Anonymous) — Thu, 6 Feb 2014 22:13:00 +0530

When monochromatic light falls on a diffraction grating diffraction patterns are produced on the other side of the grating. The angular distribution of the diffraction orders are given by

( a + b ) * sin(theta) = n*lambda

or, theta = asin(n*lambda / ( a + b ) )

where,
'( a + b )' is called grating element,

'theta' is angle of diffraction,
'n' is the order of diffraction
and 'lambda' is the wavelength of light used.

To demonstrate the variation of diffraction angle with orders, a program written using OCTAVE is presented below.
------------------------------------------------------------------------------------------------------------------

clear all
close all

ge = 2.54/15000; % ge(grating element) = (a + b)
lambda = 5893e-8; % wavelength of sodium light
n = [1 2 3];

theta = asind(n*lambda/ge);

plot(n,theta,'mh','MarkerSize',20)
xlabel('n'), ylabel('theta'),title('Angular Distribution of Diffraction Orders in Diffraction Grating')
grid on
axis([0 4 0 95])
print('fig(1).jpg')

-----------------------------------------------------------------------------------------------------------------
The result of above program is shown on the figure.

Glimpses of Hiking to Lakuri Bhanjyang.

noreply@blogger.com (Anonymous) — Tue, 7 Jan 2014 16:01:00 +0530

240 degree panoramic view from Lakuri Bhanjyang.

Tea at Lamatar-5, Dhungin, Lalitpur
(1 and half hours from Kirtipur using Public vehicles, trek starts here)

View of the city from the way towards Lakuri.

Simple map of the trekking route hanged on a home at Lakuri peak
(almost 2 hrs from Dhungin, on foot).

At Khaja ghar with "Dal", "Bhat", "Tarkari".

On the way from Lakuri to Panauti.

Boarder of Lalitpur and Kavrepalanchok District.

On the way from Lakuri to Panauti.

Panauti Bus Park (almost 4 hrs from Lakuri, on foot)

"Pi" and popular misconception.

noreply@blogger.com (Anonymous) — Sat, 2 Nov 2013 10:39:00 +0530

The number π is a mathematical constant that is the ratio of a circle's circumference to its diameter. It has been represented by the Greek letter "π" since the mid-18th century, though it is also sometimes romanticized as "pi".

Being an irrational number, π cannot be expressed exactly as a ratio of any two integers (fractions such as 22/7 are commonly used to approximate π but no fraction can be its exact value).In fact, pi has been calculated to over two quadrillion decimal places and still there is no pattern.

The value of pi to 100 significant figures is

3.14159265358979323846264338327950288419716939937510582097

4944592307816406286208998628034825342117067...

The value of pi up to 100,000 digits can be viewed on the site

http://www.geom.uiuc.edu/~huberty/math5337/groupe/digits.html

There is also a movie featuring the pattern of pi whose trailer can be viewed below.

What's The Way of Life?

noreply@blogger.com (Anonymous) — Mon, 10 Jun 2013 22:08:00 +0530

I just watched the movie "Empire of The Sun" and I loved this movie so much that I can't stop myself from writing this. Some stills are presented below.
You can view the trailer here:
http://www.youtube.com/watch?v=IKbg7RmW8rY

The most strong part is the song(background music) which is available here:
http://www.youtube.com/watch?v=77EDgeq5e78

ITER - The Way to New Energy

noreply@blogger.com (Anonymous) — Thu, 6 Jun 2013 22:12:00 +0530

If you haven't heard about ITER, chances are you will soon. The scale and scope of the ITER project rank it among the most ambitious science endeavors of our time. Building began in 2010 on the ITER platform in Cadarache, France where 34 nations are collaborating to realize the ITER project's First Plasma in November 2020.

Over the past 50 years, immense progress has been made in the fields of plasma science and fusion technology. Still, harnessing fusion power and delivering it for industrial applications remains one of the greatest challenges of our time.

ITER is based on the 'tokamak' concept of magnetic confinement, in which the plasma is contained in a doughnut-shaped vacuum vessel. The fuel—a mixture of deuterium and tritium, two isotopes of hydrogen—is heated to temperatures in excess of 150 million°C, forming a hot plasma. Strong magnetic fields are used to keep the plasma away from the walls; these are produced by superconducting coils surrounding the vessel, and by an electrical current driven through the plasma. Scroll over the machine with your cursor to identify the different parts of the machine.

What is fusion?

Fusion is the process at the core of our Sun. What we see as light and feel as warmth is the result of a fusion reaction: hydrogen nuclei collide, fuse into heavier helium atoms and release tremendous amounts of energy in the process.

In the stars of our universe, gravitational forces have created the necessary conditions for fusion. Over billions of years, gravity gathered the hydrogen clouds of the early Universe into massive stellar bodies. In the extreme density and temperature of their cores, fusion occurs.

For more details visit the links below:

http://www.iter.org/
http://www.iter.org/fusionlinks

WORKSHOP ON PLASMA PHYSICS AND INTRODUCTION OF PLASMA EXPERIMENTS AT UNIVERSITY COURSES

noreply@blogger.com (Anonymous) — Thu, 20 Dec 2012 11:35:00 +0530

A Report

WORKSHOP ON PLASMA PHYSICS AND INTRODUCTION OF PLASMA EXPERIMENTS AT UNIVERSITY COURSES

Plasma Physics studies and research have been considered important globally because of its several important industrial applications such as nuclear energy studies, material science, neutron generation, thin film deposition, surface modification, magneto-hydrodynamic generator, Plasma accelerators. To introduce these areas through different presentations by experts working in these fields, a one day workshop was organized jointly by the Department of Natural Sciences, School of Science, Kathmandu University & Central Department of Physics, Tribhuvan University on 17^th of December, 2012. The program was held at the CV Raman Auditorium hall at KU, Dhulikhel. There were altogether 26 participants in the program. The workshop was focussed basically in explaining the different aspects of Plasma studies and their application in different fields of life.

The program was inaugurated by Professor Dr. Panna Thapa, Dean of School of Sciences, Kathmandu University (K.U.). In his welcome speech, Prof. Thapa outlined a brief introduction of the various programs run by Kathmandu university and also expressed his best wishes for the success of the workshop. The program was attended by different Professors and Associate Professors of Tribhuvan University (T.U.) and K.U. Two internationally established experts on the subject Dr. Richard Kamendje (Fusion and Plasma Physicist, International Atomic Energy Agency, Vienna, Austria) and Dr. Suryakant Gupta (FCIPT Division, Institute for Plasma Research, Gandhinagar, India) were invited to participate in the workshop and guide our researchers. The inaugural by Prof. Thapa was followed by a brief description about the history and growth of Plasma Physics studies in Nepal by Professor Dr. Lok Narayan Jha, the pioneer of Plasma Physics in Nepal, Head of Central Department of Physics, T.U. Professor Dr. Jeevan Jyoti Nakarmi, T.U., the first PhD student of Dr. Jha, also shared his part along with the research areas he and his students are interested and working in. Associate Professor Dr. Raju Khanal, T.U., an active member of Plasma Physics research and development of Plasma Physics studies in Nepal, hosted the event. He too discussed his research interests and briefly discussed about his students’ research and different papers published in international journals. The Head of Department of Natural Sciences, K.U., Assoc. Professor Dr. Deepak Prasad Subedi, also an active member of Plasma Physics research and studies in Nepal, described about the experimental achievements in Nepal under his supervision. He explained about thin film deposition, surface modification and other industrial applications of Plasma Physics. Along with these experts of Plasma Physics, students of T.U. and K.U., who had some prior exposure to Plasma Physics/technology, actively participated in the program.

Dr. Kamendje gave a brief introduction to IAEA with lots of information about participation and opportunities for a developing nation like ours. He summarised the events related to the fusion since 1957 to the recent dates. Dr. Gupta, with his delightful presentation, shared the various applications of Plasma technology and importance of Plasma instrumentation.

The program was concluded with a short discussion about how to implement the wide aspects of Plasma Physics in Nepal. The workshop was full of motivation and worth attending. Everyone praised the event and supported the fact that the continuation of such programs will give much exposure to anyone related to this field.

Photo: Participants of the workshop

-Report by: Mr. Taya Nath Chetry: Participant of the workshop

Exponential decreasing nature of plasma density in a one dimensional slab by ambipolar diffusion

noreply@blogger.com (Anonymous) — Sat, 4 Aug 2012 16:51:00 +0530

This program help to visualize the exponential decreasing nature of plasma density in a one dimensional slab by ambipolar diffusion. I have chosen the particular point at distance x = 0.01m from the slab to simulate the decay of density.

% This is a program to plot the decay of plasma by ambipolar diffusion in one dimensional slab:
clear all
close all

n_o = 1e12; % initial density in m^-3
L = 0.024; % length of edge from centre of the slab in m
D = 0.4; % ambipolar diffusion coeffecient in m^2/sec
T = (2*L/pi)^2/D; % tau:mean time between collision

t = 0:.00002:.002;

x = .010;

n = n_o*exp(-(t./T)).*cos(pi*x./2/L); % density distribution

comet(t,n),xlabel('t(time of decay)'),ylabel('n(density of plasma)'),
title('exponential decay of plasma dendity at position "x = .010m" of slab')

Decay of plasma by ambipolar diffusion in one dimensional slab

noreply@blogger.com (Anonymous) — Sat, 4 Aug 2012 16:47:00 +0530

I have made a program using "GNU OCTAVE" to plot the decay of plasma by ambipolar diffusion in one dimensional slab.This program can be run in MATLAB also.You can know the beauty of this program only after you run this.

% This is a program to plot the decay of plasma by ambipolar diffusion in one dimensional slab:
clear all
close all

n_o = 1e12; % initial density in m^-3
L = 0.024; % length of edge from centre of the slab in m
D = 0.4; % ambipolar diffusion coeffecient in m^2/sec
T = (2*L/pi)^2/D; % tau:mean time between collision

x = linspace(-.024,.024);

for t = 0:.00002:.001;
n = n_o*exp(-(t./T)).*cos(pi*x./2/L); % density distribution

plot(x,n),xlabel('x(slab dimension)'),ylabel('n(density of plasma)')
axis([-0.024 0.024 0 1e12])

pause(.1) % pause the fig for .1 sec
end

A program to plot the dispersion relation for electromagnetic waves in plasma

noreply@blogger.com (Anonymous) — Tue, 26 Jun 2012 21:15:00 +0530

% A program to plot the dispersion relation for electromagnetic waves in
% plasma with B_o = 0

clear all
close all

% assign the value of constants
no = 1e18; % neutral density in m^-3
e = 1.6021e-19; % charge of electron in C
Eo = 8.8541e-12; % permittivity of free space in Fm^-1
me = 9.1095e-31; % mass of electron in kg
w_p = sqrt(no*e^2/Eo/me);% plasma frequency
c = 3e8; % speed of light in vacuum
k = linspace(-2*pi/2000,2*pi/2000,1000);
% mathematical relation of w with k
w = sqrt(w_p^2 + c^2*k.^2); % frequency of electromagnetic wave
plot(k,w)
xlabel('wave vector(k)'), ylabel('ferquency of electromagnetic wave (w)'),title('Dispersion relation for electromagnetic waves in plasma with B_o = 0')
grid on

A program to plot the dispersion relation for electron plasma waves

noreply@blogger.com (Anonymous) — Sat, 23 Jun 2012 10:54:00 +0530

I have made a program to plot the dispersion relation for electron plasma wave using MATLAB. The M-file code and plot are shown below.

% A program to plot the dispersion relation for electron plasma waves

% assign the value of constants

no = 1e18; % neutral density in m^-3
e = 1.6021e-19; % charge of electron in C
Eo = 8.8541e-12; % permittivity of free space in Fm^-1
me = 9.1095e-31; % mass of electron in kg
KT_e = 100; % temperature in ev
v_th = sqrt(2*KT_e/me); %thermal velocity
w_p = sqrt(no*e^2/Eo/me); % plasma frequency
k = linspace(-2*pi/1000000,2*pi/1000000,1000);
% mathematical relation of w with k
w = sqrt(w_p^2 + 3/2*v_th^2*k.^2); %frequency of electron plasma wave:
%w^2 = w_p^2 + 3/2*v_th^2*k.^2
plot(k,w)
xlabel('wave vector(k)'), ylabel('electron plasma ferquency(w)'),title('Dispersion relation for electron plasma wave')
grid on