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De- de Broglie Wavelength
- The wavelength associated with a particle or body.
- Dead Centre
- A centre that does not rotate.
- Dead Room
- Room characterized by a relatively large amount of sound absorption and a relatively short reverberation time.
- Debug
- To correct mistakes in both software and hardware.
- Deburr
- To remove sharp edges.
- Debye
- Unit of dipole moment.
- deca
- Prefix representing a multiplication of 10.
- Decade
- Ten times any quantity or frequency range. The range of the human ear is about 3 decades.
- Decagon
- A polygon with ten sides.
- Decalescence
- A decrease in temperature that occurs while heating metal through a range in which change in structure occurs.
- decametre
- Abbreviated as dam, unit length equal to 10m.
- Decantation
- To a separate the supernatant liquid from a solid precipitate by pouring the liquid off, being careful that all of the solid remains in the vessel.
- Decarburization
- The loss of carbon from the surface of a ferrous alloy.
- Decaying Orbit
- An unstable orbit from which the orbiting object will gradually spiral into the body it is orbiting.
- Deceleration
- Negative acceleration is called deceleration .
- deci
- Prefix representing a multiplication of 10-1
- Decibel
- The human ear responds logarithmically and it is convenient to deal in logarithmic units in audio systems.
- decilitre
- Abbreviated as dl, unit volume equal to 10-1litre.
- Decillion
- A number equal to 1033.
- Decimal Number
- A number written to the base 10.
- Decimal Prefixes
- The decimal prefixes from pico to tera.
- Decimation
- .. to lose one tenth of one's military forces in battle or as punishment...
Decimation is a terminology used in signal processing for the discarding of data
in oder to compact the data or to match the sampling rate to another data set.
- decimetre
- Abbreviated as dm, unit length equal to 10-1m.
- Decoction
- Continuous application of boiling heat to a reaction mixture.
- Decompounded
- Doubly compounded, or composed of three or more substances.
- Decrepitation
- Rapid physical decomposition of some crystals when heated. Characterized by a crackling noise.
- Decruitment
- The rapid decline in the loudness of a tone that decreases continuously in level.
- Deduction
- A conclusion derived by reasoning.
- De-Emphasis
- Filtering applied to an audio signal after storage or transmission to undo a linear
distortion due to emphasis.
- Deep Etching
- Severe etching of a metallic surface for examination.
- Defect Structure
- Relating to the kinds and concentrations of vacancies and interstitials in a ceramic compound.
- Defective Matrix
- A matrix A is defective if A has an eigenvalue whose geometric multiplicity is less than its algebraic multiplicity.
- Deficient Number
- A positive integer that is larger than the sum of its proper divisors.
- Deflagration
- To cause a substance to burn rapidly, with flame.
- Degas
- Removing air from a liquid, usually by ultrasonic or vacuum methods.
- Degenerate Orbital
- A set of orbitals are said to be degenerate if they all have the same energy.
- Degree
- A unit describing a plane angle, 1 degree = 1/90 right angle.
- Degree of Polymerization
- The average number of mer units per polymer chain molecule.
- Degrees of Freedom
- The number of degrees-of-freedom of a mechanical system is equal to the minimum
number of independent co-ordinates required to define completely the positions of all parts of the system at any instant of time.
- Dehydrator
- A separator that removes water from the system fluid.
- Del Operator
- The del or grad operation means to take the derivative with respect to distance, in 3 dimensions.
- Delamination
- Occurs when a composite material formed from a number of layers is stressed, thermally or otherwise, such that the layers begin to separate.
- Delay Line
- A transmission line or circuit that imposes a desired amount of propagation delay on an incident signal.
- Deliquescence
- Deliquescent compounds absorb so much moisture from the air that they dissolve.
- Deliquium
- Change of salt from a solid to a fluid state by contact with air only.
- Delta
- A letter of the Greek alphabet.
- Delta Iron
- An allotropic form of iron stable above 1400°C.
- Demodulation
- The process of recovering intelligence from a signal, some parameter of which was modified to carry the intelligence.
- de Moivre
- Named after the analyst and probability theorist Abraham de Moivre.
- Denaturation
- The breaking down of the three-dimensional structure of a protein resulting in the loss of its function.
- Denatured Alcohol
- Poison is added to industrial ethanol so that the tax is not charged for industrial usage.
- Dendrite
- A crystal that has a tree-like branching pattern.
- Denier
- A unit used in measuring the thickness (fineness) of yarn. It is the mass in grams of 9000m of yarn.
- Denominator
- The quantity or value on the bottom of a fraction.
- Dense Line
- The line that contains the shortest path between two points.
- Density
- The derived SI unit of density is kgm-3
- Density Function
- A mathematical function used to determine probabilities for a continuous random variable.
- Dentils
- Tooth-like ornaments used in the cornice compositions of main and porch roofs and gables.
- Deoxyribonucleic Acid
- The biological macromolecule that carries the genetic information of all eukaryotic and prokaryotic cells.
- Dependent Variable
- The dependent or response variable is the variable whose behaviour is to be measured as a result of an experiment.
- Dephlegmation
- To remove water from a solution, usually one of an acid or alcohol.
- Dephlogisticated Air
- An old name for oxygen.
- Depth Gauge
- A tool used in measuring the depth of holes or recesses.
- Depth Micrometer
- A micrometer in which the spindle projects through a flat accurately machined bar.
- Depth of Field
- The distance along the optical axis through which an object can be located and clearly defined when the lens is in focus.
- Depth of Focus
- The distance along the optical axis through which an image can be clearly focused.
- Depuration
- To free from impurities, purify.
- Derived SI Units
- These are multiplications and divisions of the basic units to form derived units.
- Derived Units
- Derived units are units constructed from a base system of units.
- Desalination
- Removal of dissolved salts from seawater.
- Desiccator
- A sealed container in which a drying agent is used to dry material that contains water.
- Design Limit
- The operational limit of a product, beyond which it not required to function properly.
- Desquamation
- The process of removing scaly crusts which form on a surface.
- Destructive Interference
- When the peaks of one wave match the troughs of another, the waves interfere destructively.
- Detector
- A device that receives energy in one form and supplies an ouput in another form.
- Deterministic Signal
- For a deterministic signal the physical phenomenon can be represented by a mathematical relationship to a reasonable degree of accuracy.
- Detonation
- Any rapid chemical reaction accompanied by noise and often heat and light, e.g., explosions.
- Deuterium
- An isotope of hydrogen that contains one neutron and one proton in its nucleus.
- Deutsches Institut für Normung
- German national organisation for standards.
- Devitrification
- The process in which a glass (noncrystalline or vitreous solid) transforms to a crystalline solid.
- Dew Point
- The temperature at which water vapour begins to condense.
- Dextrorotatory
- A chiral molecule which rotates plane-polarized light to the right.
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