Cold or contact welding is a solid-state welding process in which joining takes place without fusion / heating at the interface of the two parts to be welded. Unlike in the fusion-welding processes, no liquid or molten phase is present in the joint. Cold welding was first recognized as a general materials phenomenon in the 1940s. It was then discovered …

You may have a coal fire in you house, or you may know someone who has, and you probably don’t think twice about putting lumps of black coal on to the fire to keep you warm. But did you know that coal is made of fossilized plants? About three hundred million years million years ago, the land was very swampy …

Which is the most famous sheep in the world? A sheep called Dolly. But why is Dolly famous? That is because unlike other sheep’s, Dolly was not born in the usual manner. She is actually a carbon copy of her mother, like an identical twin. This means that she is the twin sister of her mother who is older by …

Claytronics is an emerging field of engineering, drawing on nano technology and computer engineering. Claytronics or programmable matter refers to an assemblage of tiny components called claytronic atoms or catoms, which could assume the form of any object, depending on the programmes controlling the claytronics. This term also refers to the art of making clay caricatures of public figures, begun …

Deoxyribonucleic acid (DNA) is the genetic material found in the chromosomes of all animals and plants. It is made up of only four types of organic nitrogenous bases: adenine (A), guanine (G), thymine (T) and cytosine (C). Of these, A and G are the purines and T and C are the pyrimidines. Chargaff gave the base pairing rule or the …

This is an inflammation of the membranes of the nose and throat with a thick mucous discharge. Catarrh sometimes accompanies a heavy cold, or may occur without a cold, and sometimes may be of nervous origin.

Carnival glass is pressed glass, meaning that hot molten glass which may or may not contain colour of its own is poured into metal moulds and conforms to their shape. While the glass is still hot, various solutions of metallic salts are sprayed onto the surface and the piece is reheated. The result is a piece of iridescent glassware with …

It is a method to determine the age of plants and fossils. Carbon has three naturally occurring isotopes, C12, C13 and C14. Of the three, C14 is radioactive in nature and has a half-life (decays to half the strength) of 5,730 years. Scientists measure the strength of C14 in the plant or fossil, and compare it with the expected strength …

When a satellite, natural or artificial, is orbiting its parent planet (or primary) under some conditions, the satellite revolves around itself (or spins) quite fast relative to its period of rotation around the primary, and under some other conditions, both the periods coincide. The latter phenomenon leads to the satellite facing the primary always with the same side and it …

The activity of measuring the concentration of carbon dioxide (CO 2 ) in respiratory gases during the respiratory cycle of a patient is called capnography. The equipment used in capnography usually plots the partial pressure of CO 2 in the exhaled breath as a wave form, with time on the x-axis and pressure of carbon dioxide on the y-axis. Infrared …