Th

Th
Thorium is used as an alternative reactor fuel to uranium, thorium being converted readily into uranium in the reactor.
Thallium
A soft, silvery-grey, reactive metal which is only found as a minor constituent of various minerals.
THC
Abbreviation of Total Hydrocarbons.
Theodolite
A theodolite is an instrument used in surveying for measuring horizontal and vertical angles.
Theorem
A theorem is a statement that has been proven to be true.
Theoretical Density
This is the density of a material calculated from the atomic weight and crystal structure.
Theoretical Probability
The chances of events happening as determined by calculating results that would occur under ideal circumstances.
Theoretical Rocket
An ideal Rocket.
Theoretical Yield
The amount of product obtained when all of the limiting reagent reacts.
Theory
Theories are well-established explanations for experimental data.
Theory of Relativity
Lists all Theory of Relativity topics in the Encyclopaedia
Theory of Relativity Books
Lists all Theory of Relativity Books in the Encyclopaedia
Theory of Relativity Calculations
Lists all Theory of Relativity Calculations in the Encyclopaedia
Theory of Relativity Conversions
Lists all Theory of Relativity Conversions in the Encyclopaedia
Theory of Relativity Weblinks
Lists all Theory of Relativity Weblinks in the Encyclopaedia
Therm
Unit of energy in the British and American system of units. Mainly used in the gas industry.
Thermal Conduction
The transfer of thermal energy by collisions of the atoms or molecules within a substance.
Thermal Conductivity
A measure of the ability of a material to conduct heat.
Thermal Conductivity Gauge
A pressure gauge consisting of a heated surface. The heat transported by the gas molecules from the surface is related to gas pressure.
Thermal Cycling
Subjecting a product to pre-determined temperature changes, between hot and cold extremes.
Thermal Diffusivity
The ratio of heat conducted to the heat stored per unit volume.
Thermal Efficiency
Quantity of heat produced in relation to fuel input.
Thermal Electromotive Force
The electromotive force generated in a circuit containing two dissimilar metals when one junction is at temperature different from that of the other.
Thermal Energy
The internal energy in substances, the vibration of atoms and molecules within substances.
Thermal Energy Storage
The storage of thermal energy in a system such as molten salt.
Thermal Equilibrium
Two objects are in thermal equilibrium if there is no energy flow from one to the otherand both are at the same temperature.
Thermal Expansion
The change in length of a material with change in temperature.
Thermal Fatigue
A type of fatigue failure that introduces the cyclic stresses by fluctuating thermal stresses.
Thermal Gradient
The rate at which the temperature changes with position.
Thermal Growth
Movement of the machine parts associated with a change in machinery temperature between the static and operating conditions.
Thermal Imaging Camera
A camera that detects infrared radiation and renders it as visible light thus allowing you to see the temperature of objects in the environment.
Thermal Inertia
A bulk material property related to thermal conductivity and volumetric heat capacity.
Thermal Insulation
The materials and methods used to reduce heat transfer.
Thermal Magnetic Trip Element
A single circuit breaker trip element that combines the action of a thermal and a magnetic trip element.
Thermal Noise
Random noise associated with the thermodynamic interchange of energy necessary to maintain thermal equilibruim between the circuit and its surroundings.
Thermal NOx
Nitrogen oxides generated from atmospheric nitrogen during combustion.
Thermal Relay
A switching relay in which a small heater warms a bimetal element which bends to provide the switching force.
Thermal Resistance
The property of a material, device or system that impedes the flow of heat.
Thermal Runaway
A conduction that exists when heat causes more electron-hole pairs to be generated, which, in turn, causes more heat and which may eventually cause diode destruction.
Thermal Shock
Stresses induced in a material because of a rapid temperature change or a thermal gradient.
Thermal Spring
A spring whose temperature is 6.5°C or more above mean annual air temperature.
Thermal Stress
A residual stress introduced within a body resulting from a change in temperature.
Thermal Trip Element
A circuit breaker trip element that uses the increased bending of a bimetallic strip caused by increased current to open a circuit.
Thermalox
Alternative name for Beryllium Oxide.
Thermie
Unit of heat energy.
Thermion
A thermion is an electrically charged particle emitted from a heated body.
Thermionic Emission
The production of electron emission by thermal means.
Thermistor
A resistor that varies in value according to its temperature.
Thermit Crucible
The vessel in which the thermit reaction takes place.
Thermit Mixture
A mixture of metal oxide and finely divided aluminum with the addition of alloying metals as required.
Thermit Mould
A mould formed around the parts to be welded to receive the molten metal.
Thermit Welding
A group of welding processes in which fusion is produced by heating with superheated liquid metal and slag resulting from a chemical reaction between a metal oxide and aluminum, with or without the application of pressure.
Thermite Process
The method of obtaining liquid metal by reduction of the oxide with aluminium powder.
Thermocell
Abbreviation of Thermogalvanic Cell.
Thermochemical Equation
An equation representing a chemical reaction that describes both the stoichiometry and the energetics of the reaction.
Thermochemistry
The study of heat absorbed or released during chemical changes.
Thermocline
A vertical temperature gradient in some layer of a body of water, which is appreciably greater than the gradients above and below it.
Thermocouple
A device for measuring temperatures.
Thermocouple Meter Movement
A meter movement that uses the current induced in a thermocouple by the heating of a resistive element to measure the current in a circuit; used to measure ac or dc.
Thermodynamic Equilibrium
A system is at thermodynamic equilibrium if the energy it gains from its surroundings is exactly balanced by the energy it loses, no matter how much time is allowed to pass.
Thermodynamic Free Energy
The energy in a physical system that can be converted to do work.
Thermodynamic Properties
Basic qualities used in defining the condition of a substance, such as temperature, pressure, volume, enthalpy, entropy.
Thermodynamics
The study of energy transfers and transformations.
Thermodynamics Books
Lists all Books in the Encyclopaedia
Thermodynamics Calculations
Lists all Calculations in the Encyclopaedia
Thermodynamics Conversions
Lists all Conversions in the Encyclopaedia
Thermodynamics Weblinks
Lists all Weblinks in the Encyclopaedia
Thermoelectric Cooling
Cooling based on the Peltier effect.
Thermoelectric Device
Most use the Seebeck effect devices similar to Peltier devices, but applying hot and cold sources to the surfaces.
Thermoelectricity
Phenomena in which a temperature difference creates an electric potential or an electric potential creates a temperature difference.
Thermoelectron
An electron emitted by a very hot object.
Thermogalvanic Cell
A galvanic cell consisting of two identical half cells that are kept at different temperatures.
Thermogram
A continuous trace of temperature variation with time, typically produced by a thermograph.
Thermography
The detection and display of infrared radiation.
Thermohygrograph
An instrument for measuring humidity and temperature.
Thermoluminescence
The luminescence produced in a solid when its temperature is raised.
Thermometer
An instrument for measuring temperature.
Thermometry
The science of temperature measurement.
Thermophotovoltaics
A generator burns fuel to heat a material that emits light. The light is then filtered and converted into electricity in photovoltaic (PV) cells.
Thermopile
Electronic device that converts thermal energy into electrical energy, composed of thermocouples in series or less commonly in parallel.
Thermoplastic
A polymer that softens or melts on heating, and becomes rigid again on cooling.
Thermosetting Plastic
A polymer that solidifies on heating and cannot be remelted.
Thermosphere
The region of the Earth′s atmosphere above the mesopause, starting at 80 km altitude, where the air temperature increases with altitude.
Thermostat
A device which automatically maintains temperature.
Thermostatic Control
Device which operates system or part of system based on temperature change.
Thermostatic Valve
Valve controlled by temperature change response elements.
Thermotropism
Movement of a plant in response to temperature.
Theta
A letter of the Greek alphabet.
Thevenin′s Theorem
Theorem that replaces any complex network with a single voltage source in series with a single resistance.
Thick Film Components
Passive circuit components having a thickness of 0.00001m
Thickener for Lubricating Grease
A substance composed of finely divided particles dispersed in a liquid lubricant to form the product′s structure.
Thickness Planer
A power-fed rotary planer that trims the surface of a board to a certain thickness.
Thigmotropism
Response of a plant to touch such as tendrils on a climbing plant wrapping themselves around other plants or supports.
Thin Film Components
Passive circuit elements deposited on a substrate to a thickness of 0.000001m
Thin Film Lubrication
A condition of lubrication in which the film thickness of the lubricant is such that the friction between the surfaces is determined by the properties of the surfaces as well as by the viscosity of the lubricant.
Thin Layer Chromatography
A technique for separating components in a mixture on the basis of their differing polarities.
Thin Rod
The moment of inertia of a thin rod.
Thin Shell Concrete Structure
A curved concrete surface whose thickness is small in relation to its length and width.
T-Hinge
Surface hinge with the short member attached to the jamb and the long member attached to the door.
Thio-
A prefix that means, replace an oxygen with sulphur.
Thiokol
The trade name of a synthetic rubber, derived from sodium tetrasulphide and organic dichlorides.
Third Brush
A generator in which a third, movable brush is used to control current output.
Third Class Lever
The force is applied between the load and the fulcrum.
Third Ionization Energy
Energy required to remove an electron from an isolated +2 ion.
Third Law of Thermodynamics
For changes involving only perfect crystalline solids at absolute zero, the change of the total entropy is zero.
Third Octave
Unit of frequency interval describing a band of frequencies such that the highest frequency is 21/3 times the lowest.
Thixotropic Fluid
A liquid that becomes less viscous when stirred.
Thomson Cross Section
σe = 0.665245854x10-28m2
Thomson Effect
Describes the heating or cooling of a current-carrying conductor with a temperature gradient.
Thomson, Sir Joseph John
British physicist and Nobel laureate, credited for the discovery of the electron and of isotopes, and the invention of the mass spectrometer.
Thorium
Thorium is used as an alternative reactor fuel to uranium, thorium being converted readily into uranium in the reactor.
Thou
An abbreviation of thousandths of an inch. A unit of length used by engineers.
Thousand
A number equal to 103.
Thousandths of an Inch
Often abbreviated as thou. A unit of length used by engineers.
Thread
A helical projection of uniform section on the internal or external surface of cylinder or cone.
Thread Angle
The angle formed by the two sides of the thread with each other.
Thread Axis
A line running lengthwise through the centre of the screw.
Thread Crest
The top surface joining the two sides of a thread.
Thread Depth
The distance between the crest and the root of a thread.
Thread Flank
The thread flanks join the thread roots to the crest.
Thread Height
This is the radial distance between the minor and major diameters of the thread.
Thread Length
The length of the portion of the fastener with threads.
Thread Micrometer
A micrometer in which the spindle is ground to a point having a conical angle of 60 degrees.
Thread Pitch
The distance from a point on one screw thread to a corresponding point on the next thread.
Thread Pitch Diameter
The diameter of a screw thread measured from the thread pitch line on one side to the thread pitch line on the opposite side.
Thread Rolling
Chipless, cold-forming material-displacement process where a rolling head is pressed into the workpiece to create threads.
Thread Root
The bottom surface joining the sides of two adjacent threads.
Thread Runout
The portion at the end of a threaded shank which is not cut or rolled to full depth, but which provides a transition between full depth threads and the fastener shank or head.
Threaded Insert
A threaded coil that′s used to restore an original thread size hole that has damaged threads.
Threads per Inch
The number of threads in a linear inch along the length of a threaded component.
Three Body Abrasion
A particulate wear process by which particles are pressed between two sliding surfaces.
Three Dimensional
Having length, width, and thickness i.e. space.
Three Dimensional Radar
A radar set that measures the range, bearing and altitudes of a target.
Three Electrode Cell
An electrochemical cell containing a working electrode, a counter electrode, and a reference electrode.
Three Element Array
An array with two parasitic elements and a driven element.
Three Phase Electricity
Multiple phase power supply or load that uses at least three wires where a different voltage phase from a common generator is carried between each pair of wires.
Three-Hinged Arch
A curved structure with hinges usually at each abutment and at the crown.
Three-Way Catalyst
A pollution control device which reduces all three noxious substances: HC, CO, and NOx.
Three-Way Edge Clamp
C-clamp design with a third screw that applies right angle pressure to the edge.
Threshold
The wood or metal beveled floor piece at door openings that commonly separates non-continuous floor types.
Threshold of Feeling
The threshold of feeling for a specified signal is the minimum effective sound pressure of that signal which, in a specified fraction of the trials, will stimulate the ear to a point at which there is the sensation of discomfort.
Threshold of Hearing
The equation defining the threshold of hearing.
Threshold of Pain
The minimum sound pressure level of a sound outside the ear that will produce a transition from discomfort to definite pain.
Threshold Shift
Temporary threshold shift occurs when a person has been exposed for a few hours to noise levels of about 80 dB and above.
Throttle Pedal
A pedal that when pressed is connected to the engine and demands more torque.
Throttling
An irreversible adiabatic steady flow process in which the fluid is caused to flow through an obstruction in a pipe with a resulting drop in pressure.
Through Hole
Hole or cavity cut in a solid shape that connects with other holes or extends all the way through the workpiece.
Thrust
The force exerted in any direction by a fluid jet.
Thrust Bearing
A bearing designed to only take axial or thrust load.
Thrust Specific Fuel Consumption
Fuel consumption per unit of thrust.
Thrust Vectoring
Using a directional rocket nozzle to guide flight.
Thrust Washer
A washer that is used to reduce the rotational friction of a shaft with under axial load.
Thrusters
Small reaction engines on a spacecraft that can provide thrust used to control its orbit, orientation and attitude.
Thulium
A metallic element that is a member of the rare earth group.
Thumb Drive
Another name for Flash Drive.
Thumbscrew
A screw or bolt whose head is in the shape of a flattened, vertical fin, so that the bolt can be turned by the fingers.
Thylakoid
Closed cisterna, or disc, formed by the pigment-bearing internal membranes of chloroplasts.
Thyratron
A gas-tube rectifier with a grid electrode that has the ability to initiate current flow when the anode is positive.
Thyristor
A component rather like a diode but will not conduct until a voltage is applied to its third terminal known as the gate.
THz
Abbreviation of terahertz, 1012 Hz.