Thursday, 8 September 2016

Newton's Corpuscular theory

In optics, the corpuscular theory of light, arguably set forward by Pierre Gassendi and Thomas Hobbes states that light is made up of small discrete particles called "corpuscles" (little particles) which travel in a straight line with a finite velocity and possess impetus. This was based on an alternate description of atomism of the time period. And it is supported by Planks Quantum Theory of Light.

Mechanical Philosophy

In the early 17th century, natural philosophers were seeking new information to replace Aristotelianism that had been popular for centuries. Various European philosophers adopted what came to be known as mechanical philosophy sometime between around 1610 to 1650, which described the universe and its contents as a kind of large-scale mechanism, a philosophy that explained the universe is made with matter and motion.[1] This mechanical philosophy was based on Epicureanism, and the work of Leucippus and his pupil Democritus and their atomism, in which everything in the universe, including a person's body, mind, soul and even thoughts, was made of atoms; very small particles of moving matter. During the early part of the 17th century, the atomistic portion of mechanical philosophy was largely developed by Gassendi, René Descartes and other atomists.

Sir Isaac Newton

The corpuscular theory was largely developed by Sir Isaac Newton. Newton's theory remained in force for more than 100 years and took precedence over Huygens' wave front theory, partly because of Newton’s great prestige. When the corpuscular theory failed to adequately explain the diffractioninterference and polarization of light it was abandoned in favour of Huygens' wave theory.To some extent, Newton's corpuscular (particle) theory of light re-emerged in the 20th century, as light phenomenon is currently explained as particle and wave.
Newton's corpuscular theory was an elaboration of his view of reality as interactions of material points through forces. Note Albert Einstein's description of Newton's conception of physical reality:
[Newton's] physical reality is characterised by concepts of spacetime, the material point and force (interaction between material points). Physical events are to be thought of as movements according to law of material points in space. The material point is the only representative of reality in so far as it is subject to change. The concept of the material point is obviously due to observable bodies; one conceived of the material point on the analogy of movable bodies by omitting characteristics of extensionform, spatial locality, and all their 'inner' qualities, retaining only inertiatranslation, and the additional concept of force.
  1. Every source of light emits large numbers of tiny particles known as corpuscles in a medium surrounding the source.
  2. These corpuscles are perfectly elastic, rigid, and weightless.

Wednesday, 10 August 2016

A P J Abdul Kalam Azad

A. P. J. Abdul Kalam
ஆ. ப. ஜெ. அப்துல் கலாம்


11th President of India
In office
25 July 2002 – 25 July 2007
Prime Minister Atal Bihari Vajpayee
Manmohan Singh
Vice President Krishan Kant
Bhairon Singh Shekhawat
Preceded by K. R. Narayanan
Succeeded by Pratibha Patil
Personal details
Born Avul Pakir Jainulabdeen Abdul Kalam
ஆவுல் பக்கிர் ஜைனுலாபுதீன் அப்துல் கலாம்

15 October 1931
Rameswaram, Ramnad District, Madras Presidency, British India
(now in Ramanathapuram District, Tamil Nadu, India
Died 27 July 2015 (aged 83)
Shillong, Meghalaya, India
Cause of death Cardiac arrest(Stroke)
Nationality Indian
Alma mater St. Joseph's College, Tiruchirappalli
Madras Institute of Technology
Profession Professor
Author
Aerospace scientist
Religion Islam

Early life and education

Avul Pakir Jainulabdeen Abdul Kalam was born on 15 October 1931 to a Tamil Muslim family in the pilgrimage centre of Rameswaram on Pamban Island, then in the Madras Presidency and now in the State of Tamil Nadu. His father Jainulabudeen was a boat owner and imam of a local mosque;[9] his mother Ashiamma was a housewife.[10][11][12][13] His father owned a ferry that took Hindu pilgrims back and forth between Rameswaram and the now uninhabited Dhanushkodi.[14][15] Kalam was the youngest of four brothers and one sister in his family.[16][17][18] His ancestors had been wealthy traders and landowners, with numerous properties and large tracts of land. Their business had involved trading groceries between the mainland and the island and to and from Sri Lanka, as well as ferrying pilgrims between the mainland and Pamban. As a result, the family acquired the title of "Mara Kalam iyakkivar" (wooden boat steerers), which over the years became shortened to "Marakier." With the opening of the Pamban Bridge to the mainland in 1914, however, the businesses failed and the family fortune and properties were lost over time, apart from the ancestral home.[19] By his early childhood, Kalam's family had become poor; at an early age, he sold newspapers to supplement his family's income.[20][20][21]
In his school years, Kalam had average grades but was described as a bright and hardworking student who had a strong desire to learn. He spent hours on his studies, especially mathematics.[21] After completing his education at the Schwartz Higher Secondary School, Ramanathapuram, Kalam went on to attend Saint Joseph's College, Tiruchirappalli, then affiliated with the University of Madras, from where he graduated in physics in 1954.[22] He moved to Madras in 1955 to study aerospace engineering in Madras Institute of Technology.[13] While Kalam was working on a senior class project, the Dean was dissatisfied with his lack of progress and threatened to revoke his scholarship unless the project was finished within the next three days. Kalam met the deadline, impressing the Dean, who later said to him, "I was putting you under stress and asking you to meet a difficult deadline".[23] He narrowly missed achieving his dream of becoming a fighter pilot, as he placed ninth in qualifiers, and only eight positions were available in the IAF.[24]

Career as a scientist

This was my first stage, in which I learnt leadership from three great teachers—Dr Vikram Sarabhai , Prof Satish Dhawan and Dr Brahm Prakash. This was the time of learning and acquisition of knowledge for me.
A P J Abdul Kalam[25]
After graduating from the Madras Institute of Technology in 1960, Kalam joined the Aeronautical Development Establishment of the Defence Research and Development Organisation (DRDO) as a scientist. He started his career by designing a small hovercraft, but remained unconvinced by his choice of a job at DRDO.[26] Kalam was also part of the INCOSPAR committee working under Vikram Sarabhai, the renowned space scientist.[13] In 1969, Kalam was transferred to the Indian Space Research Organisation (ISRO) where he was the project director of India's first Satellite Launch Vehicle (SLV-III) which successfully deployed the Rohini satellite in near-earth orbit in July 1980; Kalam had first started work on an expandable rocket project independently at DRDO in 1965.[1] In 1969, Kalam received the government's approval and expanded the programme to include more engineers.[25]

Kalam addresses engineering students at IIT Guwahati
In 1963 to 1964, he visited NASA's Langley Research Center in Hampton, Virginia; Goddard Space Flight Center in Greenbelt, Maryland; and Wallops Flight Facility.[11][27] Between the 1970s and 1990s, Kalam made an effort to develop the Polar Satellite Launch Vehicle (PSLV) and SLV-III projects, both of which proved to be successful.
Kalam was invited by Raja Ramanna to witness the country's first nuclear test Smiling Buddha as the representative of TBRL, even though he had not participated in its development. In the 1970s, Kalam also directed two projects, Project Devil and Project Valiant, which sought to develop ballistic missiles from the technology of the successful SLV programme.[28] Despite the disapproval of the Union Cabinet, Prime Minister Indira Gandhi allotted secret funds for these aerospace projects through her discretionary powers under Kalam's directorship.[28] Kalam played an integral role convincing the Union Cabinet to conceal the true nature of these classified aerospace projects.[28] His research and educational leadership brought him great laurels and prestige in the 1980s, which prompted the government to initiate an advanced missile programme under his directorship.[28] Kalam and Dr V S Arunachalam, metallurgist and scientific adviser to the Defence Minister, worked on the suggestion by the then Defence Minister, R. Venkataraman on a proposal for simultaneous development of a quiver of missiles instead of taking planned missiles one after another.[29] R Venkatraman was instrumental in getting the cabinet approval for allocating 388 crores for the mission, named Integrated Guided Missile Development Programme (IGMDP) and appointed Kalam as the chief executive.[29] Kalam played a major part in developing many missiles under the mission including Agni, an intermediate range ballistic missile and Prithvi, the tactical surface-to-surface missile, although the projects have been criticised for mismanagement and cost and time overruns.[29][30]
Kalam served as the Chief Scientific Adviser to the Prime Minister and the Secretary of the Defence Research and Development Organisation from July 1992 to December 1999. The Pokhran-II nuclear tests were conducted during this period in which he played an intensive political and technological role. Kalam served as the Chief Project Coordinator, along with Rajagopala Chidambaram, during the testing phase.[11][31] Media coverage of Kalam during this period made him the country's best known nuclear scientist.[32] However, the director of the site test, K Santhanam, said that the thermonuclear bomb had been a "fizzle" and criticisied Kalam for issuing an incorrect report.[33] Both Kalam and Chidambaram dismissed the claims.[34]
In 1998, along with cardiologist Soma Raju, Kalam developed a low cost coronary stent, named the "Kalam-Raju Stent".[35][36] In 2012, the duo designed a rugged tablet computer for health care in rural areas, which was named the "Kalam-Raju Tablet".[37]