Plasticity is the capacity to resist plastic deformation (dislocation movement of a solid material undergoing non-reversible changes of shape in response to applied forces), while toughness measures the ability of a material to resist crack propagation. The rocks, subjected to external forces, are deformed continuously and permanently, without however being subjected to rupture phenomena and without …

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In Metrology, tolerance means the limit or acceptable limits of the variations of a physical dimension, a physical property of a manufactured object, of a system, or other measured values such as temperature, humidity, or time. In other words, it is the maximum allowable error in the measurement is specified in terms of some value. The tolerance in mechanical devices is …

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Strain gauge accelerometer. LVDT accelerometer Capacitive. Piezoresistive and Piezoelectric accelerometer. Laser accelerometer. MEMS accelerometer. Gravimeter.


The gravimeter is a particular type of accelerometer specifically designed to measure the acceleration of gravity. According to the equivalence principle of general relativity, the effects of gravity and acceleration are the same; therefore, an accelerometer cannot distinguish between the two cases. As gravimeters, it is possible to use improved versions of accelerometers for static measurements, in …

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Wimshurst machine

The Wimshurst influence machine is is a historic electrostatic generator, a machine for generating high voltages developed between 1880 and 1883 by British inventor James Wimshurst (1832-1903). The appearance is particular and is characterized by two vertically mounted discs that rotate in the opposite direction and two metal balls for discharging. It produces electrical discharges of a …

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An airfoil (in American English) or aerofoil (in British English) is a structure shaped to produce an aerodynamic reaction – lift – at right-angles to its direction of motion. Familiar examples include the wings of an airplane, a blade (of a propeller, rotor, or turbine), or sail (as seen in cross-section).

Unit operation

In chemical engineering and related fields, a unit operation is a basic step in a process; it consists of a single physical transformation that can take place inside a chemical apparatus of a chemical plant. Unit operations involve a physical change or chemical transformation such as separation, crystallization, evaporation, filtration, polymerization, isomerization, and other reactions.


The belt is a mechanical transmission element used to connect two shafts in a slightly elastic, but integral way, through the use of pulleys, whose center distance is rather high. The most common belts are distinguished, according to their shape, in flat, trapezoid (or trapezoidal) and toothed. The most widely used material is the rubberized fabric, synthetic …

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In metallurgy, the fracture is a sudden break of metal materials due to stresses, caused by stress, applied at a point far from that in which the fracture begins. There are two major types of fractures: fragile and ductile (or tenacious).

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