Bromine is an element in the halogen group.
A structural part designed to support, strengthen or stiffen a structure to resist loads.
The symbols { and } used for grouping or to represent a set.
A horizontally projecting support.
Brackett Series
The series which describes the emission spectrum of hydrogen when the electron is jumping to the fourth orbital.
A sharp tool for making small holes either through thin materials or into soft block materials.
Bragg, Sir William Henry
British physicist, chemist, mathematician and active sporstman who uniquely shared a Nobel Prize with his son.
Bragg, Sir William Lawrence
English physicist who shared the Nobel Prize in Physics in 1915 with his father Sir William Henry Bragg.
Bragg′s Law
A relationship that stipulates the condition for diffraction by a set of crystallographic planes.
Brahe, Tycho
Danish astronomer who made precise observations of the sky.
Braids Theory
Invented by Emil Artin and is a part of the Knot Theory. Braids are collections of lines whose ends are attached to two parallel straight lines.
An organ in the body which makes decisions and controls muscles in the body.
Brake Bias
The distribution of braking between front and rear wheels.
Brake Caliper
The disc brake component that straddles the rotor and houses the piston, cylinder and brake pads.
Brake Disc Rotor
The rotating disc attached to the wheel axle and is clamped with brake pads to decelerate the vehicle.
Brake Fade
A reduction in braking performance due to the brakes overheating.
Brake Graunch
The name given to the noise made by the brakes when they are just slipping when starting (or stopping) from rest. The brake graunch is mainly exhibited on the vehicles fitted with automatic transmission, but can also occur on manual vehicles e.g., on a steep hill. It is caused by brake pad stick-slip when static and dynamic friction is very similar. The term 'creep/groan' is also used to describe the brake graunch.
Brake Horse Power
This is the useful power available at the flywheel of an engine.
Brake Judder
Brake judder is the phenomenon where with medium to heavy braking from high speed, severe vibration is felt throughout the whole vehicle. It is often attributed to a mode of vibration in which the front suspension executes a predominantly fore and aft vibration with the two road wheels in-phase with each other. Excitation is often provided by the oscillatory forcing generated when applying the brakes to a brake disk that has disk thickness variation.
Brake Mean Effective Pressure
This is the average effective cylinder pressure that does useful work calculated from the brake horse power.
Brake Pipes
Pipes used to carry hydraulic brake fluid under pressure.
Brake Power
The engine power as measured at the output shaft.
Brake Servo
A device which multiplies the driver′s physical effort in applying the brakes using the engine manifold vacuum.
Brake Specific CO
The ratio of the rate at which carbon monoxide leaves the engine exhaust manifold to the brake horsepower.
Brake Specific Fuel Consumption
The ratio of the engine fuel consumption to the engine power output.
Brake Specific HC
The ratio of the rate at which hydrocarbons leave the engine exhaust manifold to the brake horsepower.
Brake Specific NOx
The ratio of the rate at which oxides of nitrogen leave the engine exhaust manifold to the brake horsepower.
Brake Squeal
High frequency continuous tone when brakes are applied, this may be a single or multiple tones. The sound is generated by vibration on the surface of the disc itself.
Brake Thermal Efficiency
This is the ratio of Brake Power to Heat of Fuel for a heat engine.
A device used to reduce the speed of a vehicle or object.
Braking Torque
The torque required to bring a motor down to a standstill.
Brakish Water
Water having less salt than sea water, but undrinkable, having salinity values ranging from about 0.5 to 17 parts per thousand.
A diamond penetrator of specified sphero-conical shape used with a Rockwell hardness tester for hard metals.
Branched Polymer
A polymer having a molecular structure of secondary chains that extend from the primary chains.
Brass is an alloy of copper and zinc, but often other elements such as aluminium, iron, manganese, tin and lead are added.
Brass Hammer
A hammer with a brass head.
Brass Lump
The name miner′s would give to a large lump of fools gold.
Brassey, Thomas
One of the most important civil engineering contractors in the world in the nineteenth century, building railways in Britain, Europe, Asia, Australia, North and South America.
A timber tower, or projecting wooden gallery.
Braun, Werner von
German rocket engineer.
Brayton, George
American engineer who patented an internal-combustion engine that was displayed at the 1876 Centennial Exhibition in Philadelphia, Pennsylvania.
Brayton Thermodynamic Cycle
The thermodynamic cycle of the gas turbine engine. Sometimes known as the Joule Cycle.
Braze Welding
A method of welding by using a filler metal that liquefies above 450°C and below the solid state of the base metals.
Joining metals by flowing a thin layer, capillary thickness, of nonferrous filler metal into the space between them.
An assembly of preliminary circuits.
Break Elongation
The elongation of the specimen to the break point.
Breakaway Torque
The torque necessary to put into reverse rotation a bolt that has not been tightened.
Breakdown Maintenance
Maintenance performed after a machine has failed to return it to an operating state.
Breakdown Torque
The maximum torque a motor will develop at rated voltage without a relatively abrupt drop or loss in speed.
Breakdown Voltage
Voltage at which the breakdown of a dialectric or insulator occurs.
Breaking Load
Load which causes fracture in a tensile, compression, flexure or torsion test.
Breaking Stress
Also known as the ultimate tensile strength. This is the maximum stress that can be applied to a material.
Breakloose Torque
The torque required to effect reverse rotation when a pre-stressed threaded assembly is loosened.
Movements which pump air in and out of the body.
X-rays emitted when a charged particle (such as an electron) is decelerated by passing through matter.
Bremsstrahlung Effect
The emission of electromagnetic radiation as a consequence of the acceleration of charged elementary particles.
Brewsters Law
Unpolarised light can be polarised by reflection. When unpolarised light is reflected from the surface of an optical material (glass, say) then preferential reflection occurs for the electric-field vector that is perpendicular to plane of incidence.
A shaped and burnt block of clay.
Brick Bolster
A wide bladed chisel designed for cutting bricks.
Bricklayer Hammer
A special hammer for chipping cement blocks and bricks.
A structure built to span an obstacle - such as a river.
Bridge Circuit
A circuit usually diagrammed as a square formation of components which gives a null indication on a sensing device when a balance is achieved.
Bridge Rectifier
A full-wave rectifier in which there are four arms - each containing a diode.
Briggsian Logarithm
Another name for the Common Logarithm.
In acoustic terms this refers to too much high frequency energy.
Bright Dip
For high-purity aluminium an acid/copper solution is used to produce a bright clean surface.
Bright Field Imaging
A imaging mode in a TEM that uses only Unscattered Electrons to form the image.
The visual sensation of the luminous intensity of a light source.
In concert hall acoustics, a bright, clear, ringing sound, rich in harmonics, is called brilliant.
Ancient name for Sulphur.
Brindley, James
Leading canal builder in the UK.
Brinell Hardness
Characterizes the indentation hardness of materials through the scale of penetration of an indenter.
Brinell Hardness Test
A test for determining the hardness of a material by forcing a hard steel or carbide ball of specified diameter into it under a specified load.
A form of mechanical damage in which metal is displaced or upset without attrition.
Bristol Metal
A brass made with 75.5% copper and 24.5% zinc.
British Association Threads
A British system of threads with 47.5° included angle with rounded roots and crest. Even numbers are the preferred sizes.
British Standard Brass
A specialist thread form based upon the Whitworth thread and consisting of 26 threads per inch whatever the thread diameter.
British Standard Fine
A thread form based upon the British Standard Whitworth form but with a finer thread.
British Standard Pipe
A family of standard screw thread types that has been adopted internationally for interconnecting and sealing pipe ends.
British Standard Whitworth
A symmetrical V thread with an angle between the threads measured in the axial plane of 55°. 1/6 of the V, i.e. the point is truncated with arcs blended tangentially into the flanks.
British Thermal Unit
The amount of heat required to raise the temperature of 1 pound of water by 1° Fahrenheit.
Brittle Crack Propagation
A very sudden propagation of a crack with the absorption of no energy except that stored elastically in the body.
Brittle Fracture
Separation of a solid with little or no macroscopic plastic deformation.
The tendency of a material to fracture without first undergoing significant plastic deformation.
A long, tapered cutting tool with serration′s which, when forced through a hole or across a surface, cuts a desired shape or size.
Broad Axe
An axe with a wide blade that is used for felling trees.
Broad Band Signal
A random signal containing a wide range of frequency components. Some types of electrical noise in a cable and acoustic noise from turbulent flow tend to be broad band.
Broadband Coating
A multi-layer antireflection coating with reduced reflection over a broad spectral band.
Broadband Noise
Noise with components over a wide range of frequencies.
Broadside Array
An array in which the direction of maximum radiation is perpendicular to the plane containing the elements.
Broglie, Louis-Victor de
He demonstrated mathematically that electrons and other subatomic particles exhibit wavelike properties.
Brominated Flame Retardants
A group of chemicals used in plastics and textiles to give flame retardant properties.
An element in the halogen group.


A colourless volatile liquid that has an ether-like odour.



A colorless, nonflammable gas with no distinctive smell.

Bronze is an alloy of copper and tin. However, the name is now applied to other alloys that do not contain tin.
Brookfield Viscosity
Apparent viscosity determined by Brookfield viscometer.
Brösted Acid
A material that gives up hydrogen ions in a chemical reaction.
Brösted Base
A material that accepts hydrogen ions in a chemical reaction.
Brown Dwarf
These straddle the domain between stars and giant planets.
Brown, Robert
Discovered the brownian movement of minute particles.
Brownian Motion
Small particles suspended in liquid move spontaneously in a random fashion.
Brunel, Isambard Kingdom
Creator of the Great Western Railway, bridge builder and revolutionary naval architect.
Bruno, Giordano
Scientist, which, for his beliefs, the church burnt at the stake.
Brun′s Constant
The sum of the reciprocals of all twin primes.
Brush DC Motors
The Brush DC motors use commutators and carbon brushes to apply current through the windings as the motor rotates.
Sliding contacts, usually carbon, that make electrical connection to the rotating part of a motor or generator.
Brushless DC Motors
The BLDC motor uses electronic commutation to control the current through the windings.