Cr

Cr
Chromium is a bright, blue/white metal with excellent corrosion resistance.
Cr2O3
Chemical formula for Chromium Oxide.
Crack
A fracture type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement.
Crack Growth Analysis
Fatigue analysis technique that assumes the existence of a crack or flaw and looks at this propagation.
Cracking
The thermal decomposition of the molecules of high molecular mass organic compounds to produce molecules of compounds of lower molecular mass.
Crank
That part of the crankshaft, which is in the form of a crank and crank pin.
Crank Angle
Angle that can be measured between the crankshaft and top dead centre.
Crank Rumble
This is an amplitude modulation of engine noise perceived inside a car with a modulation frequency of 0.5 order.
Crank Web
One of the pair of arms which carry the big-end journal.
Crankcase
The middle part of the engine structure surrounding the working parts.
Crankcase Emissions
Pollutants allowed to escape into the atmosphere from the crankcase of an internal combustion engine.
Cranking Amps
The current required by the starter motor to crank an engine.
Crankpin
That part of the crank to which the connecting rod is attached.
Crankshaft
That part of the engine which transmits the reciprocating motion of the pistons to the driven unit in the form of rotary motion.
Crankshaft Journal
The journals running in the main bearings as opposed to those for the big-end bearings.
Crankshaft Pulley
A wheel attached to the front end of the crankshaft which is connected by fan belts to the fan, the alternator, and other devices so that the rotating crankshaft can drive these other parts as well.
Crash
Slang used to describe a program with errors that cause it to stop functioning correctly.
C Rate
Battery discharge rate.
Cray, Seymour
American electrical engineer and supercomputer architect who designed a series of computers that were the fastest in the world for decades, and founded Cray Research which would build many of these machines.
Creep
The time-dependent permanent deformation that occurs under stress.
Creep Limit
Also known as Creep Strength.
Creep Rate
Time rate of deformation of a material subject to stress at a constant temperature.
Creep Recovery
Rate of decrease in deformation that occurs when load is removed after prolonged application in a creep test.
Creep Rupture Strength
Stress required to cause fracture in a creep test within a specified time.
Creep Strength
Maximum stress required to cause a specified amount of creep in a specified time.
Creep Test
Method for determining creep or stress relaxation behaviour.
Creepage Distance
The shortest distance along the surface of an insulator from one conducting part to another, which may be energized or at ground potential.
Crenelated
Notched or indented, usually with respect to tops of walls, as in battlements.
Crest
The peak of a wave disturbance.
Crest Factor
Peak value divided by the R.M.S. value, used as a measure of the severity of a segment of data.
Cretaceous
The geological period from 144.2 million to 65 million years ago.
Crick, Francis
Noted for being one of the co-discoverers of the structure of the DNA molecule in 1953.
Crinolines
The framework of hoops used to support cladding over a boiler.
Cristae
Infoldings of the inner mitochondrial membrane.
Crith
A unit of mass sometimes used in the physics and chemistry of gases. The crith is equal to the mass of a litre of hydrogen at standard temperature and pressure, this is about 89.885 milligrams.
Critical Angle
The minimum angle of incidence for which total internal reflection occurs.
Critical Band
In human hearing, only those frequency components within a narrow band, called the critical band, will mask a given tone.
Critical Chain Reaction
A chain reaction in which an average of one neutron from each fission reaction initiates another reaction.
Critical Constant
Any of three constants associated with the critical point of a pure element or compound: critical density, critical pressure, critical temperature.
Critical Cooling Rate
The minimum rate of continuous cooling just sufficient to prevent undesired transformations.
Critical Damping
The smallest value of damping required for a displaced system to return to its equilibrium position without overshooting or oscillating about that position.
Critical Density
The density of a pure element or compound at a critical point.
Critical Distance
The distance from a sound source at which direct sound and reverberant sound are at the same level.
Critical Frequency
A particular resonant frequency at which damage or degradation in performance is likely.
Critical Mass
The minimum mass of a substance that will allow a chain reaction to continue without dying out.
Critical Molar Volume
The molar volume at the critical point.
Critical Point
The temperature or pressure at which a change in crystal structure, phase or physical properties occurs.
Critical Pressure
The pressure at the critical point.
Critical Resolved Shear Stress
The shear stress, resolved within a slip plane and direction, which is required to initiate slip.
Critical Reynolds Number
The point at which some significant change occurs.
Critical Speeds
Any rotating shaft will have lateral (or flexural) and torsional natural frequencies. If the shaft is subjected to a force at any of these frequencies, the amplitude of vibration will be particularly large.
Critical State
The state of a pure element or compound when it is at a critical point.
Critical Temperature
The temperature at the critical point.
Critical Volume
The volume occupied by a certain mass, usually one gram molecule of a liquid or gaseous substance at its critical point.
CrO2
Chemical formula for Chromium Dioxide.
Crocket
A projecting, foliate ornament of a capital, pinnacle, gable or buttress.
Crookes Dark Space
The dark space between the cathode glow and the negative glow in a vacuum tube, occurring when the pressure is low.
Crookes, William
English chemist and physicist who discovered thallium.
Cross Assembler
An assembler program that runs on a different kind of computer than that for which it generates code.
Cross Compound Turbine
Large steam turbines with parallel shafts and a generator on each shaft. The steam flows through the high pressure turbine, then is crossed-over to the low pressure turbine.
Cross Correlation
The cross-correlation function gives a measure of the extent to which two signals correlate with each other as a function of the time displacement between them.
Cross Cut Chisel
Used for cutting grooves and slots.
Cross Modulation
The modulating of a desired signal carrier by undesired signal modulation as the result of accidental mixing of the two signals in a non-linear device.
Cross Polarization
The polarization orthogonal to a reference polarization component.
Cross Section
A view showing an internal structure as it would be revealed by cutting through the piece in any plane.
Cross Sectional Area
The area of a slice of an object.
Cross Spectrum
The cross spectrum Fxy(f) of fx(t) and fy(t) is the forward Fourier Transform of the cross correlation function Rxy(T). The cross spectrum is in general complex.
Cross Talk
Unwanted breakthrough of one channel into another.
Crosscut Saw
A saw for cutting across the grain of timber.
Crosslinked Polymer
A polymer in which adjacent linear molecular chains are joined at various positions by covalent bonds.
Crossover
An electrical circuit consisting of a combination of high-pass, low-pass and bandpass filters used to divide the audio frequency spectrum (20Hz to 20kHz) into segments suitable for individual loudspeaker use.
Crossover Frequency
In a loudspeaker with multiple radiators, the crossover frequency is the 3dB point of the network dividing the signal energy.
Crosswall
An interior dividing wall of a castle.
Crosswind
Any wind that is blowing perpendicular to a line of travel.
Crowbar
Circuit used to protect the output of a source from a short circuited load.
Crown
A contour on a sheet or roll where the thickness or diameter increases from edge to centre.
Crown Glass
A silicate glass containing oxides of sodium and potassium, used in compound lenses and spectacles; harder than flint glass, with low index and low dispersion.

Crown Gold
2 carats of alloy (usually copper sometimes silver) and 22 carats of gold so called from the gold crown of 1526 which used this alloy.

Crown of Thorns Tuner
A mechanical tuning device for magnetron tubes that changes the frequency of the cavities by changing the inductance.
CRT
An evacuated tube containing an anode and a cathode that generates cathode rays when operated at a high voltage.
Crude Oil
Unrefined oil as it comes directly from the well.

Cruise Control
Control system used to maintain the vehicle speed without the invention of a driver.
Crumb
A unit of information in computer science, equal to 2 bits.
Crumple Zones
Exist at the front and rear of the vehicle to help absorb the impact of a collision.
Crush Resistance
Load required to produce fracture in a glass sphere subjected to crush loading.
Crushing Load
Maximum compressive force applied during a compression or crushing test.
Cryogenic
Operating at extremely low temperatures.
Cryogenic Gas
A gas that has been liquified by lowering the temperature, usually to a temperature under about -100C.
Cryogenic Liquefaction
The process through which gases such as nitrogen, hydrogen, helium, and natural gas are liquefied under pressure at very low temperatures.
Cryogenic Storage
Extreme low-temperature storage.
Cryohydrate
A mixture of ice and another substance in definite proportions such that a minimum melting or freezing point is attained.
Cryometer
A thermometer for measuring low temperatures.
Cryosphere
The component of the climate system consisting of all snow, ice, and permafrost on and beneath the surface of the earth and ocean.
Cryostat
Container used to isolate thermally a fluid from its environment and maintain it at low temperatures.
Cryptarithm
A number puzzle.
Cryptography
Field of mathematics and computer science concerned with information security and related issues, particularly encryption and authentication.
Crystal
A material in which the atoms are arranged in a definite geometric pattern.
Crystal Controlled Oscillator
Oscillator that uses a quartz crystal in its feedback path to maintain a stable output frequency.
Crystal Field Splitting Energy
Ligands complexed to a metal ion will raise the energy of some of its d orbitals and lower the energy of others, the difference in energy is called the crystal field splitting energy.
Crystal Field Theory
The colour, spectra, and magnetic properties of metal-ligand complexes can be explained by modelling the effect of ligands on metal′s d orbital energies.
Crystal Orientation
Arrangements in space of the axes of a crystal lattice with respect to a coordinate system.
Crystal Oven
A closed oven maintained at a constant temperature in which a crystal and its holder are enclosed to reduce frequency drift.
Crystal Structure
For crystalline materials, the manner in which atoms or ions are arrayed in space. It is defined in terms of the unit cell geometry and the atom positions within the cell.
Crystal System
A scheme by which crystal structures are classified according to unit cell geometry.
Crystalline
The state of a solid material characterized by a periodic and repeating three-dimensional arrays of atoms, ions, or molecules.
Crystallite
A region within a crystalline polymer in which all the molecular chains are ordered and aligned.
Crystallization
Act or process of forming crystals or bodies by elements or compounds solidifying.
Crystals of Silver
Old name for Silver Nitrate.