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Black Annealing
Box annealing or pot annealing ferrous alloy sheet, strip or wire.
Black Box
A unit whose output is a specified function of the input, but for which the method of converting input to output is not necessarily specified.
Black Hole
A massive star that has collapsed to such a small size that its gravitational force is so strong that not even light can escape from its 'surface'.
Black, Joseph
Scottish chemist who laid the foundations for thermodynamics.
Black Lead
Natural crystalline form of carbon, used to make vessels that resist high temperatures and in making pencils.
Black Light
Electromagnetic radiation not visible to the human eye.
Black Oils
Lubricants containing asphaltic materials, which impart extra adhesiveness, used for open gears and steel cables.
Black Oxide
Black finish on a metal produced by immersing it in hot oxidizing salts or salt solutions.
Blackbody
A hypothetical body that absorbs without reflection all of the electromagnetic radiation incident on its surface.
Blackbody Radiation
The electromagnetic radiation emitted by an ideal black body.
Blackett, Patrick Maynard Stuart
English chemist who developed the cloud chamber.
Blackman Window
A weighting that is applied in the time domain to reduce leakage within a Fourier Transform analysis.
Blackman-Harris Window
A weighting that is applied in the time domain to reduce leakage within a Fourier Transform analysis. The Blackman-Harris window has much the same performance as the Kaiser-Bessel window, except that it suppreses the sidelobes more than 92dB at a cost of an 11% wider noise bandwidth.
Blacksmith Hammer
A special hammer for hitting and shaping heated iron.
Blacksmithing
The ancient art of forging and working metal, especially iron.
Blacksmiths Vice
A vice with a long leg that transfers some of the forces into the floor.
Blackwood
A hardwood from East Africa.
Blade
An arm of a propeller or a rotating wing.
Blade Clearance
Gap between blade and casing on a gas turbine.
Blade Passing Frequency
A potential vibration frequency on any bladed machine (turbine, axial compressor, fan, etc.). It is represented by the number of blades times shaft-rotating frequency.
Blakeslee, Albert F
American botanist who applied the drug colchicine to dividing cells of plants, causing a doubling of the number of chromosomes with altered traits in the treated organisms.
Blank
A piece of metal cut or formed to regular or irregular shape for subsequent processing by forming, bending or drawing.
Blank Carburizing
Simulating the carburizing operation without introducing carbon.
Blanking Distance
Minimum sensing range in an ultrasonic proximity sensor.
Blast Furnace
A vertical shaft type furnace used for reducing iron ore to pig iron when cast or hot metal for further melting. This product is used in an open hearth or basic oxygen furnaces for production of steel.
Blast Furnace Gas
A by product obtained during the reduction of iron ore by coke in the blast furnace.

BLDC Motor
Abbreviation of Brushless DC Motor.
Bleach
A dilute solution of sodium hypochlorite or calcium hypochlorite which kills bacteria and destroys coloured organic materials by oxidizing them.
Bleed Air
Hot air, at high pressure, taken usually from the bypass section of a gas turbine engine, for heating, de-icing and other useful work.
Bleeder
A defect wherein a casting lacks completeness due to molten metal draining or leaking out of some part of the mould cavity after pouring has stopped.
Bleeder Current
A current drawn continously from a souce.
Bleeder Resistor
A resistor that allows a small current drain on a power source to discharge filter capacitors or to stabilize an output.
Blind Experiment
The subjects do not know whether they are in the treatment group or the control group.
Blind Hole
A hole made in a workpiece that does not pass through it.
Blind Reference Oil
A reference oil, the identity of which is unknown by the test facility.
Blink
A unit of time equal to 0.864 second. This unit is also called the metric second.
Blister
A defect in metal, on or near the surface, resulting from the expansion of gas in a subsurface zone.
Bloch, Felix
Won the 1952 Nobel Prize in Physics with Edward Mills Purcell for their "development of new methods for nuclear magnetic precision measurements."
Block Brazing
A brazing process in which bonding is produced by the heat obtained from heated blocks applied to the parts to be joined.
Block Companding
Normalising of the digital representation of an audio signal within a certain time period.
Block Copolymer
A linear copolymer in which identical mer units are clustered in blocks along the molecular chain.
Block Diagram
A diagram in which the major components of an equipment or a system are represented by squares, rectangles, or other geometric figures, and the normal order of progression of a signal or current flow is represented by lines.
Block Plane
A small plane designed for cutting across end grain.
Blocking
A condition in an amplifier, caused by overdriving one or more stages, in which the amplifier is insensitive to small signals immediately after reception of a large signal.
Blocking Diode
A diode connected in series with a solar cell or cells and a storage battery to keep the battery from discharging through the cell when there is no output, or low output, from the solar cell.
Blondel
Another name for an Apostlib.
Blood
A liquid that circulates inside the bodies of animals.
Blood Cells
Any cells contained in the blood.
Blood Group
A human is born with one of four main types of blood.
Blood Pressure
The pressure of blood in the main arteries in an animal.
Blood Vessel
A tube that carries blood around the body of an animal.
Bloom
Generally a rolled product from an ingot generally greater than 36 square inches in area, this is the first operation in the production of bars or structurals.
Blow By
Passage of unburned fuel and combustion gases past the piston rings of internal combustion engines, resulting in fuel dilution and contamination of the crankcase oil.
Blow Down Cock
A valve mounted low-down on the boiler, often around the foundation ring, which is used to periodically vent water from the boiler.
Blow Holes
Voids or holes in a casting that may occur due to entrapped air or shrinkage during solidification of heavy sections.
Blowby
The combustion products and unburned air-and-fuel mixture that blows past the piston rings and enters the crankcase.
Blowdown Wind Tunnel
An open-circuit wind tunnel in which gas stored under pressure is allowed to expand through a test section to provide a stream of gas or air to test a model.
Blowhole
A defect in a casting caused by trapped steam or gas.
Blown Flaps
Aerodynamic surface over which bleed air is discharged at high speed to prevent breakaway of the normal airflow.
Blue Brittleness
Brittleness exhibited by some steels after being heated to some temperature within the range of 150 to 350C.
Blue Shift
The apparant (Doppler) shift of the wavelength towards the higher frequency region of radiation emitted by an approaching object.
Blue Supergiant
A supergiant star with spectral type O or B.
Blue Vitriol
An old fashioned name for hydrated copper sulphate.
Blueprint
A pen or ink line drawing reproduced (printed) on sensitised paper by direct exposure.
Blueprinted Engine
Ensuring the dimensions of the parts in the engine are more accurate and, therefore, closer to the original engine blueprint values.
Blume, John A
The father of earthquake engineering.
Blumlein, Alan Dower
Most famously responsible for inventing and patenting a stereo recording system.
Blunder
A gross mistake caused by carelessness or poor judgement.
Blur Circle
The image of a point-source object formed by an optical system on its focal surface.