Archives July 2013

"When the plumbers and sanitary engineers had done their work... diseases began to vanish." Lewis Thomas, medical researcher and essayist It was probably more the need to get rid of foul smells than an understanding of the health hazards of human waste that led to the first proper sewage systems. While most early settlements grew up next to natural waterways—-into which waste from latrines was readily channeled—the emergence of major cities exposed the inadequacy of this approach. Early civilizations, like that of the Babylonians, dug cesspits below floor level in their houses and created crude drainage systems for removing storm water. But it was not until around 2500 B.C.E. in the Indus Valley that networks of precisely made brick-lined sewage drains were constructed along the streets to convey waste from homes. Toilets in homes on the street side were connected directly to these street sewers and were flushed manually with more...

India is a great country having extensive borders. Its total borderline is nearly 15000 kms. Its northen frontier stretches from Kashmir and goes up to Arunachal Pradesh and Assam, touching the border of Burma and Bangladesh. On the periphery of India, lie many countries. In the north, Kashmir is surrounded by Afghanistan, Pakistan, Tibet and China. Ladakh is the tri-junction where the frontiers of these three countries kiss each other. Afghanistan is though now friendly towards India, Pakistan and China are hostile. Along the entire Himalayan range lies the kingdom of Bhutan. The Himalayan kingdom has a benevolent king. Its customs, costumes, religion and manners are quite akin to India. There is the beautiful Himalayan kingdom of Nepal. Nepal is a country, situated in the heart of the mighty  Himalayas. Its capital is Kathmandu. Kathmandu is a lovely valley. India and Nepal are closely linked culturally and historically. The borders more...

"I wanted to work in the visible spectrum... and everybody else was working in the infrared." Nick Holonyak The LED (light-emitting- diode) is a semiconductor device. All semiconductors have a variable ability to conduct electric current because of impurities (caused by trace chemical additives) in their structure. An N-type impurity adds an extra electron to the semiconductor, and a P-type impurity provides an electron hole. Electrons, negatively charged particles, naturally move from areas with many electrons (negative) to areas with few electrons (positive). In a diode, an N-type material is placed next to a. P-type one, and the two are sandwiched between electrodes. This setup only allows electric current (a stream of electrons) to flow in one direction, from the N-type side's electrode to the P-type side's electrode. When an electron drops into an electron hole, it releases energy in the form of a photon. As a result, when electrons more...

Introduction. Today, India is facing a lot of problems. But population problem is worst from all of them. Due to this problem we fall short of our resources. The countries having limited population are fully developed in nil the sectors. India is a great country. It has 2.4% area of the whole world. At the time of our independence in 1947, the population of our country was merely 33 crore but now we have crossed more than one thousand millions. Present Indian position. Indian population has increased four times .since our independence. We stand in the second position after China in world population. It will create havoc if it continues to increase at the same  rate in next twenty-five years. Due to this population problem in India, all our plannings or policies become unsuccessful. Reasons of population explosion. In India, the main reason behind  this grim problem is illiteracy. The more...

Today man's knowledge of science is very wide and highly advanced. It has helped him to discover and invent many things for his comforts and efficiency Computer is the latest and the most efficient and beneficial invention of science. In 1854, George Boole invented the logic system which is the basis for today's digital computers. In 1937, the first electro machine calculator was developed by Howard and Dilton. In 1946, the first computer came into existence. It  was named as ENIAC (Electronic Numerical Integrator and Calculator). It was developed by Dr. John Nouchly and J.P. Eckert of University of Pennasylvannia U.S.A. In 1951 Remington Rand Corporation of USA brought out a commercial computer named UNIVAC (Universal Automatic Computer). Transistor technology gave birth to second generation of computers. These were smaller in size, more reliable, and have higher speed of operation. A third generation computer consisted of IBN - 370 types. more...

Co-education is a system of education in which boys and girls learn together in the same school or college at the same time. In India this system has become very popular nowadays. Needless to say that it is not a new thing for us. It has been in practice from a long time, though not like today. But with the coming of Muslims in India, co-education came to an end because of the Purdha system of which the muslims were the great advocates. Time is changing very fast and with the change of age and expansion of education co-education is no longer a taboo now. What to talk of big towns and cities, even in villages and small towns boys and girls study together without any problem. Actually the idea of common people has sharply changed. They are no longer narrow-minded. Apart from this, there are many advantages of co-education more...

In India, the legislature at the central level is called Parliament. The Indian Parliament is bicameral. It consists of  two houses. The lower house is called the Lok Sabha or the House of the people. The upper house is called the Raiya  Sabha or the council of States. The President of India is .in integral part of the Indian Parliament. The two houses of  Parliament  are constituted in different ways. They do not enjoy equal powers. The first elected Parliament came into in  April 1952. Lok Sabha, as the name itself signifies, is the body representative of the people. It consists of members of directly elected by the people. The maximum strength of Lok sabha  has been fixed at 552. Out of these, 530 members are has  by the people from different states and to 20 members are  elected from the union territories. Besides, the President In the power to more...

Sir William Hamilton (1899-1978) already had some experience of working with water-based mechanics when he invented the jet boat. In 1954, he had built a jet pump, the first of its kind. The pump was essentially a system for water propulsion. It used a propeller to create a centrifugal force that caused a forward thrust action underwater, drawing water through and back inside the pump. The jet boat works in a similar way to the jet pump. Simply put, a traditional screw propeller accelerates a large volume of water by a small amount and, in agreement with Newton's Third Law of Physics—for every action there is an equal and opposite reaction—a large amount of thrust is created. This thrust is used to drive the boat and allows it to move speedily through the currents. Hamilton lived and worked in New Zealand. There his boat was able to power quickly through more...

Being a woman in science in the early 1900s was difficult for American neurophysiologist Ida Hyde (1857-1945). Born in Davenport, Iowa, to German immigrant parents, she struggled to find a university that would accept her. She eventually earned a bachelor's degree at Cornell University and later became the first woman to earn a PhD in science at the University of Heidelberg, in Germany. Despite this, Hyde was still not acknowledged for her invention of the microelectrode until after her death. Since then, the microelectrode has revolutionized neuro-physiology. Hyde's electrode was so small that at the time her methods were among the first capable of studying single cells. Hyde's research focused on the breathing mechanism and nervous systems of a range of organisms, from grasshoppers to humans. During her research, she invented the microelectrode so that she could deliver electrical or chemical stimuli to a cell and record the electrical activity more...

"The Catseye is what great design is all about. Simple, functional, and beautiful" James May, presenter of British TV show Top Gear One night in 1933 when the road mender Percy Shaw (1890-1976) was driving home in Yorkshire, he saw the light of his car headlamps reflected in the eyes of a cat beside the road. This gave Shaw the inspiration that by replicating this effect he could produce a practical way of helping drivers navigate poorly lit roads. Shaw's challenge was to create a device bright enough to illuminate roads at night, robust enough to cope with cars constantly driving across it, and that also required minimum maintenance. Shaw came up with a small-device that could be inserted into the road as -a marker. It consisted of four glass beads placed in two pairs facing in opposite directions, embedded in a flexible rubber dome. When vehicles drove over the more...


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