Mechanical Engineering, PRI-SEM
Mechanical engineering, the branch of engineering concerned with the design, manufacture, installation, and operation of engines and machines and with manufacturing processes. It is particularly concerned with forces and motion.
Mechanical Engineering Encyclopedia Articles By Title
prism, in optics, a piece of glass or other transparent material cut with precise angles and plane faces, useful......
productivity, in economics, the ratio of what is produced to what is required to produce it. Usually this ratio......
proportional counter, type of ionization chamber capable of differentiating between various kinds of charged particles......
protractor, any of a group of instruments used to construct and measure plane angles. The simplest protractor comprises......
proving ground, area used for testing devices and equipment, usually, though not always, military. Testing, in......
proximity fuze, an explosive ignition device used in bombs, artillery shells, and mines. The fuze senses when a......
psychological testing, the systematic use of tests to quantify psychophysical behaviour, abilities, and problems......
psychrometer, a hygrometer composed of two similar thermometers. The bulb of one thermometer is kept wet (by means......
pulley, in mechanics, a wheel that carries a flexible rope, cord, cable, chain, or belt on its rim. Pulleys are......
pupil, in optical systems, the virtual image of an aperture associated with mirrors, prisms, and lenses and their......
pyrometer, device for measuring relatively high temperatures, such as are encountered in furnaces. Most pyrometers......
qa, ancient Babylonian liquid measure equal to the volume of a cube whose dimensions are each one handbreadth (3.9......
quad, unit of energy equal to 1 quadrillion (1015) British thermal units (BTUs). The quad is a convenient unit......
Daniel Quare was a celebrated English clock maker who invented a repeating watch mechanism (1680) that sounded......
quart, unit of capacity in the British Imperial and U.S. Customary systems of measurement. For both liquid and......
quarter days, the days that begin each quarter of the year. In England they are March 25 (Lady Day), June 24 (Midsummer......
quipu, accounting apparatus used by Andean peoples from 2500 bce, especially from the period of the kingdom of......
R-7, Soviet/Russian missile and launch vehicle. Under the direction of the rocket pioneer Sergey Korolyov, the......
rack and pinion, mechanical device consisting of a bar of rectangular cross section (the rack), having teeth on......
rad, the unit of absorbed dose of ionizing radiation, defined in 1962 by the International Commission on Radiological......
radar, electromagnetic sensor used for detecting, locating, tracking, and recognizing objects of various kinds......
radial engine, Type of internal-combustion engine used mainly in small airplanes, in which the cylinders (ranging......
radiation measurement, technique for detecting the intensity and characteristics of ionizing radiation, such as......
- Introduction
- Gamma Rays, X-Rays, Interactions
- Neutron Interactions
- Dosimeters, Geiger Counters, Scintillators
- Track-Etch, Detectors, Dosimetry
- Active Detectors
- Counting, Spectroscopy, Systems
- Detection, Efficiency, Instruments
- Gas, Filled, Detectors
- Proportional Counters, Detection, Applications
- Geiger-Muller, Detection, Counting
- Semiconductor, Detectors, Dosimetry
- Silicon Detectors
- Inorganic Scintillators
- Photon Detection, Charge Conversion, Photomultiplier
- Fast Neutron, Detectors, Scintillators
radio interferometer, apparatus consisting of two or more separate antennas that receive radio waves from the same......
radiometer, instrument for detecting or measuring radiant energy. The term is applied in particular to devices......
radiosonde, balloon-borne instrument for making atmospheric measurements, such as temperature, pressure, and humidity,......
rainmaking, any process of increasing the amount of precipitation discharged from a cloud. Primitive methods, such......
Ramadan, in Islam, the ninth month of the Muslim calendar and the holy month of fasting. It begins and ends with......
ramjet, air-breathing jet engine that operates with no major moving parts. It relies on the craft’s forward motion......
Jesse Ramsden was a British pioneer in the design of precision tools. Ramsden was apprenticed as a boy to a cloth......
range finder, any of several instruments used to measure the distance from the instrument to a selected point or......
Rankine cycle, in heat engines, ideal cyclical sequence of changes of pressure and temperature of a fluid, such......
Rankine temperature scale, scale established in 1859 by Scottish engineer and physicist William John Macquorn Rankine......
ratchet, mechanical device that transmits intermittent rotary motion or permits a shaft to rotate in one direction......
Raytheon Company, major American industrial corporation with core manufacturing concentrations in defense and aerospace......
razor, keen-edged cutting implement for shaving or cutting hair. Prehistoric cave drawings show that clam shells,......
reactance, in electricity, measure of the opposition that a circuit or a part of a circuit presents to electric......
Nathan Read was an American engineer and inventor. Read attended and taught at Harvard University, and soon thereafter......
reamer, rotary cutting tool of cylindrical or conical shape used for enlarging and finishing to accurate dimensions......
recoilless rifle, any of several antitank weapons developed during World War II. They are lightweight and can be......
rectifier, device that converts alternating electric current into direct current. It may be an electron tube (either......
reflection, abrupt change in the direction of propagation of a wave that strikes the boundary between different......
refraction, in physics, the change in direction of a wave passing from one medium to another caused by its change......
rehabilitation robot, any automatically operated machine that is designed to improve movement in persons with impaired......
Georg von Reichenbach was a German maker of astronomical instruments who introduced the meridian, or transit, circle,......
relative aperture, the measure of the light-gathering power of an optical system. It is expressed in different......
rem, unit of radiation dosage (such as from X rays) applied to humans. Derived from the phrase Roentgen equivalent......
repeating rifle, rifled shoulder arm typically designed with a spring-loaded tubular or box magazine holding metallic......
resistance, in electricity, property of an electric circuit or part of a circuit that transforms electric energy......
resistor, electrical component that opposes the flow of either direct or alternating current, employed to protect,......
responsive environments, the use of sensory technology and computer equipment to create a collaborative relationship......
reversing thermometer, oceanographic device for measuring underwater temperature and pressure. It consists of two......
revolver, typically, a repeating pistol that utilizes a multichambered revolving cylinder behind one barrel. Some......
rheostat, adjustable resistor used in applications that require the adjustment of current or the varying of resistance......
Jean Richer was a French astronomer whose observations of the planet Mars from Cayenne, French Guiana, in 1671–73......
Richter scale (ML), quantitative measure of an earthquake’s magnitude (size), devised in 1935 by American seismologists......
ricochet, in gunnery, rebound of a projectile that strikes a hard surface, or the rebounding projectile itself.......
rifle, firearm with a rifled bore—i.e., having shallow spiral grooves cut inside the barrel to impart a spin to......
Richard Roberts was a British inventor known for his great versatility. Roberts began his career as an uneducated......
Sir William Chandler Roberts-Austen was an English metallurgist noted for his research on the physical properties......
Roberval balance, linked mechanism invented in 1669 by the French mathematician Gilles Personne de Roberval and......
robot, any automatically operated machine that replaces human effort, though it may not resemble human beings in......
rod, old English measure of distance equal to 16.5 feet (5.029 metres), with variations from 9 to 28 feet (2.743......
roentgen, unit of X-radiation or gamma radiation, the amount that will produce, under normal conditions of pressure,......
Rolamite, mechanical roller-band device that functions as an almost frictionless suspension system for rollers;......
roller, farm implement used to break up lumps left by harrows and to compact the soil, eliminating large air spaces.......
roller bearing, one of the two members of the class of rolling, or so-called antifriction, bearings (the other......
Rolls-Royce PLC, major British manufacturer of aircraft engines, marine propulsion systems, and power-generation......
Roman republican calendar, dating system that evolved in Rome prior to the Christian era. According to legend,......
root-mean-square voltage, equivalent direct current (DC) voltage of an alternating current (AC) source. Certain......
Elmo Roper was an American pollster, the first to develop the scientific poll for political forecasting. Three......
rotary engine, internal-combustion engine in which the combustion chambers and cylinders rotate with the driven......
router, portable electric power tool used in carpentry and furniture making that consists of an electric motor,......
Royal Armouries, in the United Kingdom, a collection of weapons and armour that was originally situated in the......
Sir Henry Royce, Baronet was an English industrialist who was one of the founders of Rolls-Royce Ltd., manufacturer......
Réaumur temperature scale, scale established in 1730 by the French naturalist René-Antoine Ferchault de Réaumur......
sabre, heavy military sword with a long cutting edge and, often, a curved blade. Most commonly a cavalry weapon,......
SAE number, code for specifying the viscosity of lubricating oil, established by the U.S. Society of Automotive......
salinometer, device used to measure the salinity of a solution. It is frequently a hydrometer that is specially......
Samsung, South Korean company that is one of the world’s largest producers of electronic devices. Samsung specializes......
sarin, synthetic organophosphate compound that is highly toxic to the nervous system. Exposure to sarin—which is......
Saturday, seventh day of the week...
Horace Bénédict de Saussure was a Swiss physicist, geologist, and early Alpine explorer who developed an improved......
Thomas Savery was an English engineer and inventor who built the first steam engine. (Read James Watt’s 1819 Britannica......
saw, tool for cutting solid materials to prescribed lengths or shapes. Most saws take the form of a thin metal......
sawing machine, device for cutting up bars of material or for cutting out shapes in plates of raw material. The......
scanning electron microscope (SEM), type of electron microscope, designed for directly studying the surfaces of......
scanning tunneling microscope (STM), type of microscope whose principle of operation is based on the quantum mechanical......
Wilhelm Schickard was a German astronomer, mathematician, and cartographer. In 1623, he invented one of the first......
Eugène Schneider was one of the great industrialists of the 19th century and a prominent figure in French politics.......
Schwarzlose machine gun, early Austrian water-cooled machine gun (q.v.) operating on the blowback principle. A......
scissors, cutting instrument consisting of a pair of opposed metal blades that meet and cut when the handles at......
screw, in machine construction, a usually circular cylindrical member with a continuous helical rib, used either......
screwdriver, tool, usually hand-operated, for turning screws with slotted heads. For screws with one straight diametral......
scruple, unit of weight in the apothecaries’ system, equal to 20 grains, or one-third dram, and equivalent to 1.296......
Robert C. Seamans, Jr. was an American aeronautical engineer who pioneered in the development of advanced systems......
Secchi disk, in oceanography, circular plate about 30 centimetres (one foot) in diameter, painted a flat white......
second, fundamental unit of time, now defined in terms of the radiation frequency at which atoms of the element......
selenium cell, photoelectric device used to generate or control an electric current. Selenium photocells are commonly......
semiautomatic pistol, handgun that utilizes either recoil or blowback to discharge the empty cartridge, reload,......