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Moment of truth
The word 'nanotechnology' is first coined by University of Tokyo researcher Norio Taniguchi back in 1974.

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cobalt steel Eng.
A group of alloy steels containing 5% - 12% of cobalt and 14% - 20% of tungsten, usually with a small amount of other metals such as chromium and vanadium.They are very hard and their main use is in high-speed machinary tools and drill bits for drilling hard metals and alloys.

cofactor Biochem.
A nonprotein component essential for the normal catalytic behavior of an enzyme. Cofactors can be organic molecules or inorganic ions including metal ions. They play roles in activating the enzyme by altering its shape in such a way that enzymatic activity can occur, or even participate in the actual enzymatic chemical process.

color index (B-V) Astron.
Numerical measurement of a star color. The V refers to visual magnitude which is the magnitude of the apparent brightness as seen by the naked eye and can be measured by photometry. In early days, photometry was carried out by measuring the exposure of a star on a photographic plate that is more sensitive to the blue than it is to red. This gives a measurement of star brightness weighted towards the blue end of the spectrum. This is the B or photographic magnitude. The difference B - V is also known as the B - V color index. Bluish stars tend to have negative numbers while red stars have positive numbers. For example, a blue star of spectral class B0 will have a color index of about -0.29, while a yellow star of spectral class G0 will have a value of about 0.59.

colligative property Chem.
A property of a solution that depends on the number of solute molecules present and not the nature of the solute. Examples of colligative property are lowering of vapor pressure, elevation of boiling points. For instance, adding table salt to water caused the water to boil at a higher temperature.

compound Chem.
It is a substance made of more than one atoms that are combined in a fixed proportion. It is formed by a chemical process and, unlike a mixture, it cannot be separated by physical means. The atoms, which can be different or similar types, are bound together by chemical bonds.

Condy's fluid Med., Chem.
A mixture of sodium and potassium permanganate (manganate(VII), MnO4-) used as an antiseptic.

Conservation of baryon number Phys.
A conservation law in particle physics that states that in any process, the total baryon number must remain constant. For example, antiprotons are produced when a proton (p) beam is incident on a target of protons:

proton collisions

The total baryon number at the left-hand side of the equation is 2 and the right-hand side is 1 + 1 + 1 - 1 which is also equal to 2. Hence the above process is valid. No violation of the law has been observed, so far.

Conservation of lepton number Phys.
Law in particle physics that states that in any process, the lepton number for electron-type leptons, muon-type leptons and tau-type leptons must each remain constant. All leptons are assigned with a lepton number +1, whereas all antileptons are assigned -1. All other particles will have a value of 0. The Law stipulates that the lepton number from the left-hand side of a equation process must be equal to that from the right-hand side. For example, the negative muon decay process:

negative-muon decay process

On the right, Lm = 1 (for m-) and on the left Lm = 1 (for nm); and on the right Le=0 and on the left Le for electron and the electron antineutrino are +1 and -1, respectively. Hence, the sum of Le = 0. This means that the above muon decay process is valid.

Conservation of strangeness Phys.
A conservation law in particle physics which states that in a process that is governed by the strong or electromagnetic interactions, the total strangeness must remain the same. However, if the process is governed by the weak interaction, the total strangeness either remains the same or changes by one unit. For example, in the weak interaction involving decays of kaon plus (K+, a meson)

kaon decay

The strangeness on the right is +1, while strangeness on the left is 0 (m+ is an antilepton while nm is a lepton). Hence, according to the conservation law, the above mentioned weak interaction decay can occur.

consolute temperature Chem.
The temperature above which two partially miscible liquid components become fully miscible.

constantan Eng.
A copper-nickel alloy with an electrical resistance that changes only very slightly over a limited range of temperature, normally around room temperature. It consists of 50-60% copper and 40-50% nickel. It is used in resistance wire, thermocouples, etc. An example of a constantan is an alloy of 55% copper and 45% nickel, which has a temperature coefficient of resistance of 0.00002.

contact process Chem.
A modern method for industrial production of sulfuric acid. Introduced by a British vinegar merchant P. Phillips in 1831, the process involved roasting of sulfur or pyrite (FeS) in air and pass over a platinum catalyst to produce sulfur trioxide, which can produce concentrated sulfuric acid. The process was further improved by the German chemical company BASF (Badische Anilin -und Soda-Fabrik) in 1915 by replacing the platinum catalyst with the less expensive and more efficient vanadium pentoxide (V2O5).

contour farming Agri.
Farming sloped land on the contour, or at right angle to the natural slope in order to reduce erosion, protect soil fertility and to improve water usage.

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