Mechanical Engineering, OCH-RAN
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
Ellen Ochoa is an American administrator and former astronaut who was the first Hispanic woman to travel into space......
October, 10th month of the Gregorian calendar. Its name is derived from octo, Latin for “eight,” an indication......
odometer, device that registers the distance traveled by a vehicle. Modern digital odometers use a computer chip......
Hans Joachim Pabst von Ohain was a German designer of the first operational jet engine. After obtaining his doctorate......
ohm, abbreviation Ω, unit of electrical resistance in the metre-kilogram-second system, named in honour of the......
ohmmeter, instrument for measuring electrical resistance, which is expressed in ohms. In the simplest ohmmeters,......
onager, in weaponry, ancient Roman torsion-powered weapon, similar to a catapult. It consisted of a single vertical......
opinion poll, a method for collecting information about the views or beliefs of a given group. Information from......
optical axis, the straight line passing through the geometrical centre of a lens and joining the two centres of......
optical image, the apparent reproduction of an object, formed by a lens or mirror system from reflected, refracted,......
optical interferometer, instrument for making precise measurements for beams of light of such factors as length,......
optical pumping, in physics, the use of light energy to raise the atoms of a system from one energy level to another.......
oscillator, any of various electronic devices that produce alternating electric current, commonly employing tuned......
oscillograph, instrument for indicating and recording time-varying electrical quantities, such as current and voltage.......
oscilloscope, device that plots the relationships between two or more variables, with the horizontal axis normally......
William Oughtred was an English mathematician and Anglican minister who invented the earliest form of the slide......
ounce, unit of weight in the avoirdupois system, equal to 116 pound (437 12 grains), and in the troy and apothecaries’......
p-n junction, in electronics, the interface within diodes, transistors, and other semiconductor devices between......
David Packard was an American electrical engineer and entrepreneur who cofounded the Hewlett-Packard Company, a......
Robert Morris Page was an American physicist known as the “father” of U.S. radar. Page changed his major from theology......
panzer, series of battle tanks fielded by the German army in the 1930s and ’40s. The six tanks in the series constituted......
Panzerfaust, shoulder-type German antitank weapon that was widely used in World War II. The first model, the Panzerfaust......
Panzerschreck, shoulder-type rocket launcher used as an antitank weapon by Germany in World War II. The Panzerschreck......
parallel circuit, an electrical path that branches so that the current divides and only part of it flows through......
Paris Gun, any of several long-range cannon produced by the German arms manufacturer Krupp in 1917–18 during World......
parsec, unit for expressing distances to stars and galaxies, used by professional astronomers. It represents the......
particle accelerator, any device that produces a beam of fast-moving, electrically charged atomic or subatomic......
pascal (Pa), unit of pressure and stress in the metre-kilogram-second system (the International System of Units......
Blaise Pascal was a French mathematician, physicist, religious philosopher, and master of prose. He laid the foundation......
Pascaline, the first calculator or adding machine to be produced in any quantity and actually used. The Pascaline......
Lewis Paul was an English inventor who devised the first power spinning machine, in cooperation with John Wyatt.......
Wolfgang Paul was a German physicist who shared one-half of the Nobel Prize for Physics in 1989 with the German-born......
Peacekeeper missile, intercontinental ballistic missile (ICBM) that was part of the United States’ strategic nuclear......
pebble chopper, primordial cutting tool, the oldest type of tool made by forerunners of modern humans. The tool......
peck, unit of capacity in the U.S. Customary and the British Imperial Systems of measurement. In the United States......
pendulum, body suspended from a fixed point so that it can swing back and forth under the influence of gravity.......
pentode, vacuum-type electron tube with five electrodes. Besides the cathode filament, anode plate, and control......
percussion lock, in firearms, ignition system of small arms that utilizes an explosive that detonates when sharply......
period, in geology, the basic unit of the geologic time scale; during these spans of time specific systems of rocks......
periscope, optical instrument used in land and sea warfare, submarine navigation, and elsewhere to enable an observer......
Jacob Perkins was an American inventor who produced successful innovations in many fields. About 1790 Perkins built......
pH meter, electric device used to measure hydrogen-ion activity (acidity or alkalinity) in solution. Fundamentally,......
Royal Philips (formerly Philips Electronics) is a major Dutch manufacturer of consumer electronics, electronic......
phon, unit of loudness level. The loudness level of a sound is a subjective, rather than an objective, measure.......
photocathode, an element of a photoelectric cell (q.v.) that emits electrons when struck by light, making possible......
photocomposition, method of assembling or setting type by photographing characters on film from which printing......
photoelectric cell, an electron tube with a photosensitive cathode that emits electrons when illuminated and an......
photometer, device that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared......
photometry, in astronomy, the measurement of the brightness of stars and other celestial objects (nebulae, galaxies,......
photomultiplier tube, electron multiplier tube that utilizes the multiplication of electrons by secondary emission......
Jean Picard was a French astronomer who first accurately measured the length of a degree of a meridian (longitude......
pike, medieval infantry weapon, a long spear with a heavy wooden shaft 10 to 20 feet (3 to 6 metres) long, tipped......
pint, unit of capacity in the British Imperial and U.S. Customary systems of measurement. In the British system......
pistol, small firearm designed for one-hand use. According to one theory, pistols owe their name to the city of......
piston and cylinder, in mechanical engineering, sliding cylinder with a closed head (the piston) that is moved......
pitot tube, instrument for measuring the velocity (speed) of a flowing fluid. Invented by Henri Pitot (1695–1771),......
planer, metal-cutting machine in which the workpiece is firmly attached to a horizontal table that moves back and......
pliers, hand-operated tool for holding and gripping small articles or for bending and cutting wire. Slip-joint......
plow, most important agricultural implement since the beginning of history, used to turn and break up soil, to......
Polaris missile, first U.S. submarine-launched ballistic missile (SLBM) and the mainstay of the British nuclear......
population inversion, in physics, the redistribution of atomic energy levels that takes place in a system so that......
Poseidon missile, U.S. submarine-launched ballistic missile introduced in 1971 to replace the Polaris missile.......
pound, unit of avoirdupois weight, equal to 16 ounces, 7,000 grains, or 0.45359237 kg, and of troy and apothecaries’......
Francis Ashbury Pratt was an American inventor. With Amos Whitney he founded the Pratt & Whitney Co. in Hartford......
precision, reference to how close a set of repeated measurements are to one another. Precision is frequently distinguished......
pressure gauge, instrument for measuring the condition of a fluid (liquid or gas) that is specified by the force......
price index, measure of relative price changes, consisting of a series of numbers arranged so that a comparison......
printed circuit, electrical device in which the wiring and certain components consist of a thin coat of electrically......
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......