Kinesiology >> Human Motion

Types of Motions

Classification based on path of motion

·  translatory motion (linear motion, translation)： a motion in which all parts of the moving body move toward the same direction

·  linear (or rectilinear) motion： a motion in which all parts of a moving body move in the same direction and the path follows a straight line
·  curvilinear motion： a motion in which the net motion of a moving body move toward the same direction although the path follows a curved line, e.g. the path of the center of mass of the body during level walking
		circular motion： a special form of curvilinear motion, which is the motion when a body moves along a circumference of a circle

·  rotary motion (angular motion, rotation)： a motion in which the object acts as a radius and all parts of the moving object rotate in the same angular direction and follow a circular path about a pivot point

·  angular motion： the rotary motion with one side of the moving object fixed, e.g. rotation of a limb

·  spin： the rotary motion with the axis of rotation around the center of mass

　

Classification based on repetition of motion

·  single motion： movement performed only once

·  repeated motion： same movement pattern that is done many times in a given time

·  reciprocal motion

·  oscillation： repeated motions in a small amplitude

·  pendulum motion： repeated motions like a pendulum

　

Classification based on degree of freedom

·  degree of freedom (DOF)： a minimum number of kinematic variables required to specified all positions and orientations of the segments in a body system i.e.

·  the number of planes in which the segments move

·  the number of the primary axes which the segments possess

·  Examples:

·  The joint that moves in one plane possesses one axis and has one degree of freedom

·  For the glenohumeral joint, there are three angular degrees of freedom and three linear degrees of freedom.

　

Classification based on relative segment kinematics

·  kinematic chain： a series of connected segment links

·  open kinematic chain motion： the joint motion with the distal segment moves free in space, e.g. raising lower leg or throwing a ball

·  closed kinematic chain motion： the joint motion with the distal segment is fixed, e.g. standing up or squatting down

·  In Neumann's book, "distal-on-proximal segment kinematics" and "proximal-on-distal segment kinematics" were used in stead of open and closed kinematic chain motion, respectively (Neumann 2002, p.7).

·  What kind of kinematic chain is performed as one-legged squatting?

　

Classification based on presence of muscle contraction

·  active motion： the motion that is caused by muscle contraction

·  passive motion： the motion that is created by sources other than muscle, such as from gravity

　

Classification based on joint kinematics

·  osteokinematic movement： movements between 2 bony segments

·  arhtrokinematic movement： movements between 2 articular surfaces

Prafulla Chandra Ray

Prafulla Chandra Ray (1861-1944)

  

Many scientists are happy to make their discoveries, but are not interested in making a business of it. But a few rare ones understand why it's important to build bridges between science and industry. Prafulla Chandra Ray was the first Indian to realize this.

EARLY LIFE AND EDUCATION: 

Prafulla Chandra was born on 2 August 1861 in Raruli-Katipara, a village in the District of Khulna (in present day Bangladesh). After attending the village school, he went to Kolkata, where he studied at Hare School and the Metropolitan College. The lectures of Alexander Pedler in the Presidency College, which he used to attend, attracted him to chemistry, although his first love was literature. He proceeded to the University of Edinburgh on a Gilchrist scholarship where he obtained both his B.Sc. and D.Sc. degrees.

In 1889, Prafulla Chandra was appointed an Assistant Professor of Chemistry in the Presidency College, Kolkata. His publications on mercurous nitrite and its derivatives brought him recognition from all over the world. Equally important was his role as a teacher - he inspired a generation of young chemists in India thereby building up an Indian school of chemistry. Famous Indian scientists like Meghnad Saha and Shanti Swarup Bhatnagar were among his students. Here also he got a dedicated team and he started working on compounds of gold, platinum,iridium, etc. with mercaptyl radicals and organic sulphides. A number of papers were published on this work in the Journal of the Indian Chemical Society.

CONTRIBUTION: 

In 1904 Prafulla Chandra proceeded to Europe on a study tour and visited many famous chemical laboratories. In England, Germany, France and other European countries, he was welcomed by scientists at universities and research institutions. He had useful discussions with them. They praised his famous work on Mercurous Nitrite, Ammonium Nitrite etc. Some universities conferred honorary Doctorates on him. He made the acquaintance of famous scientists like William Ramsay, James Dewar, Perkin, Van't Hoff and Berthelot.

Prafulla Chandra Ray wanted to use the marvels of science for lifting up the masses. Many of his articles on science got published in renowned journals of his time. Ray was a very passionate and devoted social worker and he participated eagerly and actively in helping out the famine struck people in Bengal in 1922. He promoted the khadi material and also set up many cottage industries. He was a true rationalist and he was completely again the caste system and other irrational social systems etc. He persistently carried on this work of social reformation till he passed away.

ACHIEVEMENTS:

The first volume of Ray’s celebrated work, The History of Hindu Chemistry, was published in 1902. The second volume was published in 1908. It was Marcellin Pierre Eugene Berthelot (1827-1907), who inspired Ray to undertake this monumental work. In the preface to the first edition Ray wrote:” …I was brought into communication with M. Berthelot some five years ago – a circumstance which has proved to be a turning point, if I may so say, in my career as a student of the history of chemistry. The illustrious French savant, the Doyen of the chemical world, who has done more than any other persons to clear up the sources and trace the progress of chemical science in the West, expressed a strong desire to know all about the contribution of the Hindus, even went the length of making a personal appeal to me to help him with information on the subject. In response to his sacred call I submitted to him, in 1898, a short monograph on Indian alchemy; it was based chiefly on Rasendra Samgraha, a work which I have since then found to be a minor importance and not calculated to throw much light on the vexed question as to the origin of the Hindu Chemistry. M. Berthelot not only did me the honour of reviewing it at length but very kindly presented me with a complete set of his monumental work, in three volumes, on the chemistry of the Middle Ages, dealing chiefly with the Arabian and Syrian contributions on the subject, the very existence of which I was not till then aware of. On perusing the contents of these works I was filled with the ambition of supplementing them with one on Hindu chemistry.” Ray’s Hindu Chemistry was immediately recognized as a unique contribution in annals of history of science. Berthelot himself wrote a 15-page review in Journal des Savant in its issue of January 1903. Renowned international journals like Nature and Knowledge wrote very highly of the book. In 1912 the Vice Chancellor of Durham University, while conferring the Honorary DSc degree on Prafulla Chandra Ray, noted: “…his fame chiefly rests on his monumental History of Hindu Chemistry, a work of which both the scientific and linguistic attainments are equally remarkable, and of which, if on any book, we may pronounce that it is definitive.”

Bengal Chemicals

A century ago, many chemicals and medicines had to be imported from abroad. Most Indians could not afford them. P.C. Ray was then a professor at Presidency College, Kolkata. He thought that if a factory could be set up in India, it could make chemicals at much cheaper rates, using local raw materials. Therefore, in 1893, P.C. Ray started the Bengal Chemical & Pharmaceutical Works (or Bengal Chemicals in short). He put his entire savings of Rs. 700 in it. Those days it was a huge sum of money.

The factory started to make things like surgical instruments, talcum powder, toothpaste and glycerine soap. The cost of these items was lesser than imported ones. Most Indians could buy them easily. Seeing P.C. Ray, many other rich citizens began to establish other industries. His company still exists today and makes important drugs & chemicals like vitamins, cosmetics and anti-asthma drugs.

FOR THE SAKE OF SCIENCE:

Prafulla Chandra worked in this college for twenty years. He remained a bachelor all his life. All these twenty years he lived in a simple room on the first floor of the college. Some of his students who were poor and could not live anywhere else shared his room. In 1936, when he was 75 years old, he retired from the Professorship.

LEGACY:

Tagore, when presiding over his seventieth birthday celebration, said:

It is stated in the Upanishads that The One said, 'I shall be Many'. The beginning of Creation is a move towards self-immolation. Prafulla Chandra has become many in his pupils and made his heart alive in the hearts of many. And that would not have been at all possible had he not unreservedly made a gift of himself. The glory of this power in Prafulla Chandra as teacher will never be worn out by decrepitude. It will extend further in time through the ever-growing intelligence of youthful hearts ; by steady perseverance they will win new treasures of knowledge.

In 1941 the Calcutta University and the public celebrated his eightieth birthday. Acharya Prafulla Chandra Ray passed away on the 16th of June 1944; he died in the same room he had occupied for twenty-five years. He was 83 years old at the time.

This summarises the effect and influence that Prafulla Chandra had on his followers and countrymen.