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Messages - Mohammad Hassan Murad

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31
Science Discussion Forum / FOSSIL FUEL USE AND GLOBAL WARMING
« on: May 22, 2012, 01:35:04 PM »
        The world has become increasingly dependent on the use of fossil fuels (coal, oil, and natural gas) to support consumer-driven societies and their associated lifestyles. Enormous quantities of these fuels are used daily. The fuels may be burned in a variety of vehicles to propel them down the road, through the air, or across the oceans. The fuels may be utilized to drive industrial manufacturing processes directly, such as by powering an engine, or they may be used indirectly to generate electricity to power the economy by producing the consumer products upon which we’ve become so dependent. Our ability to heat and cool our homes; grow, harvest, transport, and cook our food; provide health care and medicines; and entertain ourselves during our free time all depend on fossil fuels in one way or another. Some activities depend on burning the fuels whereas others depend on utilizing the fossil fuels as raw materials in the chemical industry. Fossil fuels are nonrenewable resources, however, and the supply will eventually run out. It is becoming increasingly apparent that the products of fossil fuel combustion may be causing Earth to warm beyond what is natural and desirable. It is a known fact that both carbon dioxide and water vapor absorb and trap heat radiation. It is also known that the levels of carbon dioxide and some other heat-trapping substances have increased significantly in the atmosphere over the past hundred or so years. The debate among scientists, politicians, and concerned citizens centers on whether the warming of Earth is due to the increase in concentration of these substances. If so, what will be the consequences of this warming? And is there anything we can or should do about it?
        Some people believe this global warming will be good for Earth, some think it will be inconsequential, some think we will adjust to it, and some think it threatens life as we know it. Some people think there is nothing that can or should be done about this warming, whereas others feel it is imperative that we do everything within our power to halt this phenomenon. The average citizen must become knowledgeable enough about this issue to make informed decisions concerning factors affecting this global warming. Such knowledge could influence the type of automobile you purchase, the size of the house you live in, and your lifestyle in general. It could eventually influence where and how you live or, possibly, even if you live. Knowledge is power and only by obtaining, properly assessing, and utilizing this knowledge can we adjust to changing times.

Excerpted from the book
Joesten, M., et al. The World of Chemistry Essentials, 4th edition, Thomson, Brooks/Cole, 2007.

32
Science Discussion Forum / Re: Success of Bangladeshi Talent
« on: May 16, 2012, 03:55:50 PM »
Dear Rashed Sir, I think you made a mistake about the name. Its Sayeef Salahuddin not Saif Salaudding.

Biography

Sayeef Salahuddin received his B.Sc. in Electrical and Electronic Engineering from BUET (Bangladesh University of Engineering and Technology) in 2003 and PhD in Electrical and Computer Engineering from Purdue University in 2007. He joined the faculty of Electrical Engineering and Computer Science at University of California, Berkeley in 2008. His research interests are in the interdisciplinary field of electronic transport in nano structures currently focusing on novel electronic and spintronic devices for low power logic and memory applications. Professor Salahuddin has championed the concept of using 'interacting systems' for switching, showing fundamental advantage of such systems over the conventional devices in terms of power dissipation. He received the Kintarul Haque Gold Medal from BUET in 2003, the Meissner fellowship from Purdue University, 2003-4, an IBM PhD Fellowship 2007-8, a MARCO/FCRP Inventor Recognition Award in 2007, a UC Regents Junior Faculty Fellowship in 2009, a Hellman Faculty Fellowship in 2010, a DOE NISE award in 2010, the 2011 NSF CAREER award and the IEEE Nanotechnology Early Career Award in 2012.

The following website would be helpful to the readers
http://www.eecs.berkeley.edu/Faculty/Homepages/salahuddin.html

33
Science Discussion Forum / Amicable Numbers
« on: May 16, 2012, 12:54:08 PM »
Amicable Numbers

A pair of numbers is amicable if each is the sum of the proper divisors of the other. The smallest pair is 220 and 284. The proper divisors of 220 sum to,
                                           1 + 2 + 4 + 5 + 10 + 11 + 20 + 22 + 44 + 55 + 110 = 284
and similarly,
                                                              1 + 2 + 4 + 71 + 142 = 220.
According to the philosopher Iamblichus (c. AD 250–330), the followers of Pythagoras “call certain numbers amicable numbers, adopting virtues and social qualities to numbers, such as 284 and 220; for the parts of each have the power to generate the other,” and Pythagoras described a friend as “one who is the other I, such as are 220 and 284.”

The first few amicable pairs are: (220, 284), (1184, 1210), (2620, 2924), (5020, 5564), (6232, 6368)

In the Bible (Genesis 32:14), Jacob gives 220 goats (200 female and 20 male) to Esau on their reunion. There are other biblical references at Ezra 8:20 and 1 Chronicles 15:6, while 284 occurs in Nehemiah 11:18. These references are all to the tribe of Levi, whose name derives from the wish of Levi’s mother to be amicably related to his father. They were also used in magic and astrology. Ibn Khaldun (1332–1406) wrote that “the art of talismans has also made us recognize the marvelous virtues of amicable (or sympathetic) numbers. These numbers are 220 and 284. . . . Persons who occupy themselves with talismans assure that these numbers have a particular influence in establishing union and friendship between individuals.” (Ore 1948, 97)

To see the full article download the following attached file.

34
Science Discussion Forum / Grand Unified Theory (GUT)
« on: May 15, 2012, 07:48:20 PM »
                                                                                   Toward a Grand Unified Theory

Ever since Sir Isaac Newton identified the gravitational force, all the forces of nature have come very close to unification in theory. Electricity and magnetism were found to be linked as the same force early in the twentieth century. Then, after gravity and electromagnetism, two more forces were discovered at the beginning of the twentieth century: the “strong” and “weak” nuclear forces of the atomic nucleus.
Whereas the electromagnetic and gravitational forces operate over relatively large distances, the strong and weak nuclear forces operate over distances confined to the diameter of an atom. The strong force holds the individual parts of the nucleus together, and the weak force, through “beta radiation,” is responsible for the decay of the nucleus itself. A subatomic particle called a “neutrino” reacts within the core of the atom and participates in some nuclear reactions. Although neutrinos do not react with mass, they interact with other subnuclear particles through the weak force. Most of the neutrinos that affect Earth are generated in the center of the Sun’s thermonuclear core.
The theory developed by Sheldon Glashow (Born 1932), Abdus Salam (1926-1996), and Steven Weinberg (Born 1933) is called the electroweak theory. For the first time it precisely detailed the interaction of the electromagnetic (large) force and the weak (small) force. It also stated that the neutrino and the electron are members of the same family of particles; in effect, the neutrino is the electron’s “little brother.” The theory predicted the existence of what are called “neutral currents.” When the electron changes its identity to a neutrino and vice versa, the theory predicts that a “charged current” will be manifested in advance of the change of charge. Concurrently, a “neutral current” is present as the neutrino “acts without changing identity.”

The unification of all the forces into a single, unified mathematical theory has been a dream of physicists. The development of the electroweak theory brought that “grand unified theory” one step closer to being discovered.


Excerpted from
Magill’s Choice Science and Scientists, Salem Press Inc., 2006.
Weinberg, S. A Unified Physics by 2050?, Scientific American, Special edition 2003.

35
Science Discussion Forum / Newton & the apple story
« on: April 26, 2012, 06:36:10 PM »
     Sir Isaac Newton (1642-1727) was born on Christmas Day of 1642 at the farm of his mother’s parents near Grantham in Lincolnshire, after his father had died. He was raised by his maternal grandparents and then enrolled in Trinity College, Cambridge, in 1661, to study mathematics under Isaac Barrow (1630-1677). After completing his degree in 1665, he returned home for nearly two years to escape an outbreak of the plague. During this isolation, he began to formulate his ideas about universal gravitation after making a connection between the fall of an apple and the motion of the Moon.

Legend has it that Newton’s interest turned to gravity when he was struck on the head by a falling apple. Is it an apocryphal story?

I'll be saying more on this topic in my forthcoming post.

36
Science Discussion Forum / Galileo & the leaning tower of Pisa
« on: April 26, 2012, 06:22:32 PM »
Aristotle’s Errors
     One of Aristotle’s predictions, which was passed down to the seventeenth century, concerned the behavior of falling bodies. Aristotle, adhering to his philosophy that all effects require a cause held that all motion (effect) required a force (cause), and hence that falling (a motion) required a force (the weight, or what we now know as mass, of the object falling). The Italian astronomer and mathematician Galileo Galilei was one of a number of scientists who questioned the Aristotelian view of the workings of nature and turned to experimentation to find answers. According to legend, Galileo dropped a bullet and a cannonball from the tower to show that all objects fall with the same acceleration.

Did Galileo really drop two objects from the tower?

I'll discuss this topic in details in my forthcoming post.

37
Science Discussion Forum / Re: Earliest mathematicians
« on: April 26, 2012, 05:39:27 PM »
For the interested readers, who want to know more about the earliest history and historical development of egyptian, babylonian, mesopotamian, greek mathematics, I would like to recommend the following books of my collection.

Newman, J. R. The World of Mathematics Vol. 1-4, Simon & Schuster, 1956.
Boyer, C. B., Merzbach, U. T. A History of Mathematics, foreword by Isaac Asimov, 2nd ed. Wiley, 1991
Boyer, C. B., Merzbach, U. T. A History of Mathematics, foreword by Isaac Asimov, 3rd ed. Wiley, 2011
Cooke, R. The History of Mathematics A Brief Course, Wiley, 2005
Hodgkin, L. A History of Mathematics From Mesopotamia to Modernity, Oxford University Press, 2005.
Martzloff, J. C., Wilson, S. History of Chinese Mathematics, Springer, 2006
Gregersen, E. (ed.) The Britannica Guide to History of Mathematics, Britannica Education Publishing, 2011
Stillwell, J. Mathematics and Its History, 3rd ed. Springer, 2010.
Robson, E., Stedall, J. The Oxford Handbook of The History Of Mathematics, Oxford University Press, 2009.
Burton, D. The History of Mathematics An Introduction, McGraw-Hill, 2005.
Kleiner, I. Excursions in the History of Mathematics, Birkhäuser, 2012.
González-Velasco, E. A. Journey through Mathematics Creative Episodes in Its History, Springer, 2011.
Gow, J. A Short History of Greek Mathematics, Cambridge library collection, Cambridge University Press, first published in 1884, digital version printed in 2010.
Robson, E. Mathematics in Ancient Iraq A Social History, Princeton University Press, 2008.
Tabak, J. Mathematics and the Laws of Nature Developing the Language of Science The History of Mathematics, Revised ed. Facts on File, 2011.

38
Science Discussion Forum / Tale of an Imaginary Number
« on: April 26, 2012, 04:23:48 PM »
     In our college mathematics probably we all have learned about the imaginary number i. We were simply introduced i as a number.
Is it a number?
What kind of number is i ?
Where does the name imaginary come from?
Is it really an imaginary number? If yes then how did this number get involved into the real mathematics?
Can imaginary number do the same thing or different thing as real number do or more?
British mathematical physicist Roger Penrose calls i magic number. What is magical about i?

To explore this readers are requested to download and read the attached file. Author hopes to have some constructive comments from the scholars.

39
Science Discussion Forum / What is an Imaginary Number?
« on: April 26, 2012, 02:31:18 PM »
In our college mathematics probably we all have learned about the imaginary number. We were simply introduced i as a number. Our traditional introduction to imaginary number does not make us see the inner beauty. And it does not fascinate us. Have we ever thought about imaginary number as follows?
1. Is imaginary number a number?
2. What kind of number is i?
3. Where did the name imaginary come from?
4. Is it really an imaginary number? If yes then how did this number get involved into the real mathematics?
5. Can imaginary number do the same thing or different thing as real number do or more?
British mathematical physicist Sir Roger Penrose calls i magic number. What is magical about i?

I am preparing an article on this beautiful fascinating subject and hope to post it soon.

40
Science Discussion Forum / Re: What is gravitation?
« on: April 26, 2012, 01:41:49 PM »
Author keeps the hope to write more on this topic. Thanks for your constructive comment.

41
Science Discussion Forum / Re: Solar power
« on: April 25, 2012, 06:03:03 PM »
Thank you Tariq for giving us the information about Solar Energy. To know more about this type of energy I would like to recommend you and readers to read the following book

Tabak, J. Solar and Geothermal Energy, Facts on File, 2009

and  the following article
Crabtree, G. W., Lewis, N. S. Solar energy conversion, 37-42, Physics Today March 2007.

42
Science Discussion Forum / What is gravitation?
« on: April 25, 2012, 04:50:58 PM »
What is gravitation? Is it simply one of the four fundamental forces of nature, or something else?
What is gravitation according to Sir Isaac Newton?
What is gravitation according to Albert Einstein?
What major change Einstein had brought us about Newtonian picture of gravitation?
Lets have a look.

GRAVITATION
          Gravitation is a universal attractive force exerted by any two physical bodies on each other, even though they may be separated by a large distance. Gravitation is responsible for making objects fall to the surface of the Earth (gravitational attraction of the object by the Earth), for the nearly circular motions of the planets around the sun (gravitational attraction of the planets by the sun), for the structure of stars and planets (gravitational attraction balanced by pressure forces of constituent particles towards each other), and for the structure of star clusters and galaxies (hundreds of millions of stars would fly apart from each other if not held together by gravity). Gravitation also controls the rate at which the universe expands, and is responsible for the growth of small inhomogeneities in the expanding universe into galaxies and clusters of galaxies. Gravity is the weakest of the four fundamental forces known to physics, but it dominates on large scales because it is a long-distance force that is locally always attractive (in contrast to the far stronger electromagnetic force, which can both attract and repel, and cancels itself out on large scales). Thus gravitation is a dominant force in every day life, as well as in the motions of stars and planets and in the evolution of the cosmos. Indeed, it is one of the forces that makes our existence possible by enabling the formation and stability of plants like Earth that are hospitable to life. Without gravity (at approximately the strength it has on Earth) evolution of life would be difficult if not impossible. This fact can naturally lead to speculation that the existence and specific nature of gravitation could be part of a grand design allowing self-assembling structures to come into existence and lead to intelligent life. In this way, gravity can have theological significance.

Classical physics



            Italian astronomer Galileo Galilei (1564–1642) first recognized in the early seventeenth century that when air resistance can be neglected, objects accelerate at the same rate towards the surface of the earth, irrespective of their physical composition. Thus a feather and a cannon ball will arrive at the same time at the earth’s surface if simultaneously released from rest at the same height in a vacuum chamber. This means there is a universal rate of acceleration downwards caused by the earth’s gravitational field—approximately 32 feet per second squared—irrespective of the nature of the object considered. Gravitational potential energy can be converted to kinetic energy, with total energy conserved, as for example in a roller coaster or a pole vaulter. This enables gravity to do useful work, as in a clock driven by weights or a water mill, but it also means people must work to go uphill. Gravity can also be a danger to people, who can fall or be hurt by falling objects. Despite this danger, gravity is an essential part of the stability of every day life—it is the reason that objects stay firmly rooted on the ground rather than floating into the air.
In the late seventeenth century, Isaac Newton (1642–1727) showed that the gravitational attraction of objects towards the earth and the motion of the planets around the sun could be described accurately by assuming a universal attractive force between any two bodies, proportional to each of their masses and to the inverse of the square of the distance between them. The attractive nature of gravity results because masses are always positive. On this basis he was able to explain both the universal acceleration towards the surface  of the earth observed by Galileo and the laws of motion of planets around the sun that had been observationally established earlier in the century by Johannes Kepler (1571–1630).
This was the first major unification of explanation attained in theoretical physics, showing that two phenomena that initially appeared completely unrelated had a unified origin. Newton’s account of gravitation also explained why the direction of gravity varies at different places on the surface of the earth (always being directed towards its center), allowing “up” to be different directions at different places on the earth’s surface (Australia and England, for example). In conformity with the rest of theoretical physics, Newton’s theory of gravity can be reformulated as a variational principle (Hamilton’s principle or Lagrange’s equation s) based on minimization of particular combinations of kinetic energy and gravitational potential energy along the trajectory followed by a particle. Gravity by itself is a conservative theory (energy is conserved), so there is no friction associated with the motion of stars and planets in the sky, and their motion is fully reversible; the past and future directions of time are indistinguishable, as far as gravity is concerned. Newton was puzzled as to how the force of gravity, as described by his equations, could succeed in acting at a distance when there was no apparent contact between the bodied concerned. Pierre Laplace (1749-1827), a French physicist and mathematician, essentially resolved this puzzle by introducing the idea of a gravitational force field that fills the empty space between massive bodies and mediates the gravitational force between them. The concept of such fields became one of the major features of classical physics, particularly in the case of electromagnetism. In quantum theory the idea gravitational fields is revised and understood as a force mediated by the interchange of force carrying particles.

Einstein and after

          In the early twentieth century, Albert Einstein (1879–1955) radically reshaped the understanding of gravity through his proposal of the general theory of relativity, based on the idea that space-time is curved, with the space-time curvature determined by the matter in it. This theory predicts the motion of planets round the sun more accurately than Newtonian theory can, and also predicts radically new phenomena, in particular, black holes and gravitational radiation. Insofar as science has been able to test these predictions, they are correct. A problem with the theory is that it predicts that under many conditions (for example, at the start of the universe and at the end of gravitational collapse to form a black hole), space-time singularities will occur. Scientists still do not properly understand this phenomenon, but presumably it means that they will have to take the effect of quantum theory on gravity into account. General Relativity does not do so; it is a purely classical theory. Quantum gravity theories try to develop a theory of gravity that generalizes Einstein’s theory and is also compatible with quantum theory. Even the way to start such a project is unclear. Approaches include twistor theory, lattice theories, noncommutative geometries, loop variable theories, and superstring theories. None has reached a satisfactorily developed state, however, much less been tested and shown to be correct. Indeed, in many ways such theories are likely to be untestable. The most ambitious are the superstring theories, now extended into a metatheory of uncertain nature known as M-theory, which promises to provide a unified theory of all fundamental forces and particles. M-theory still has far to go before making good on that promise. Despite the lack of a definite quantum theory of gravity, various attempts have been made to develop quantum theories of cosmology. These theories also face considerable conceptual and calculational problems. The satisfactory unification of quantum theory and general relativity theory, perhaps in some unified theory of all the fundamental forces, remains one of the most significant outstanding problems of theoretical physics. The desire to develop a practical antigravity machine remains one of humanity’s outstanding wishes. No present theory offers a way to such a machine, but the negative gravitational effect of the vacuum energy will continue to inspire some to hope that one day such a machine might exist. 

Based on the entry by George F. R. Ellis published in Encyclopedia of Science and Religion ed. J. Wentzel Vrede van Huyssteen, Thompson Gale, 2003.

To explore more
D’Inverno, R. Introducing Einstein’s Relativity. Oxford: Oxford University Press, 1996.
Ellis, G. F. R., and Williams, R. M. Flat and Curved Spacetimes. Oxford: Oxford University Press, 2000.
Hawking, S. W., Ellis, G. F. R. The Large-scale Structure of Spacetime. Cambridge, UK: Cambridge University Press, 1973.
Misner, C. W.; Thorne, K. S.; and Wheeler, J. A. Gravitation. San Francisco: W. H. Freeman, 1973.
Thorne, K. S. Black Holes and Time Warps. New York: Norton, 1994.

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