Da

da
Prefix representing a multiplication of 10
DAB
Abbreviation of Digital Audio Broadcasting.
DAC
Abbreviation of Digital-to-Analogue Converter.
Dacite
Volcanic rock that characteristically is light in colour and contains 62% to 69% silica and moderate a mounts of sodium and potassium.
Daguerre, Louis-Jacques-Mande
French artist and inventor; developed the daguerreotype photochemical process.
dalton
The atomic mass unit is sometimes called the dalton, after John Dalton.
Dalton, John
He developed atomic theory that accounts for the law of conservation of mass, law of definite proportions and law of multiple proportions.
Dalton′s Law of Partial Pressures
The total pressure of a mixture of gases, which do not interact chemically, is equal to the sum of the partial pressures.
Dam
Generally serves the purpose of retaining water.
dam
Abbreviation of decametre, unit length equal to 10m.
Damped Natural Frequency
The frequency at which a damped system will oscillate in a free vibration situation.
Damped Wave
A ringing sinusoidal oscillation or oscillatory wave consisting of an initial pulse or peak followed by additional peaks of diminishing amplitude.
Damper
Device used to reduce unwanted vibrations of a system.
Damping
Dissipation of energy in a system, either through time or distance.
Damping Factor
The ratio of actual damping in a system to its critical damping.
Damping Pad
Material applied to add damping to another material to reduce structural vibrations. This layer may be constrained or unconstrained.
Damping Ratio
Also known as Damping Factor, the ratio of actual damping in a system to its critical damping.
Damps
Any dangerous vapours in caves, mines etc.
Dangling Bonds
A chemical bond associated with an atom on the surface layer of a crystal.
Danjon Scale
A scale measuring the darkness of lunar eclipses.
DAQ
Abbreviation of Data Acquisition.
daraf
A unit of electrical elastance, which is the ability of an electric potential to charge a capacitor.
Darcets Alloy
A low melting point alloy.

darcy
A CGS unit of permeability.
Darcy, Henry
Hydraulic Engineer, best known for Darcy′s law.
Dark Current
Thermally induced current of a detector in the absence of an optical signal.
Dark Field Imaging
Using a single diffracted beam to form the image in a TEM.
Dark Matter
Matter that is in space but is not visible to us because it emits no radiation by which to observe it.
Darlington Pair
Two directly coupled transistors in which the emitter of the first drives the base of the second.
Darwin, Charles
Darwin struck upon the theory of evolution.
Dashpot
A damping device, usually consisting of a cylinder and a piston in which relative motion of either displaces a fluid such as air or oil, resulting in friction.
Data
A series of facts or statements that may have been collected, stored, processed or manipulated but have not been organized.
Data Acquisition
Collecting and measuring electrical signals from sensors, transducers, and test probes or fixtures and inputting them to a computer for processing.
Data Mile
Unit of distance used in radar technology. The data mile equals exactly 6000 ft.
Data Mining
Using automated data anlysis techniques to find themes or relationships.
Data Processing
The execution of a systematic sequence of operations performed upon data. Synonymous with information processing.
Data Transmission
The transfer of information from one place to another or from one part of a system to another.
Database
Information organised into interrelated tables of data and information.
Datalogger
An electronic device that automatically records and stores signals from transducers for later analysis.
Date
A number or series of numbers used to identify a given day with the least possible ambiguity.
Date Stamp
Information added to data to indicate the date at which it was collected.
Daughter Isotope
In a nuclear equation the compound remaining after the parent isotope (the original isotope) has undergone decay.
DaughterBoard
A board that rides piggyback on another board, such as the motherboard or an expansion card.
Davenport, Thomas
Blacksmith and inventor who established the first commercially successful electric streetcar.
Davisson-Germer Experiment
An experiment that conclusively confirmed the wave nature of electrons.
Davy, Sir Humphry
English scientist who invented the first electric light in 1800.
Day
Traditional unit of time marked by one rotation of the Earth on its axis.