cylinder(redirected from crossed cylinders)
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cylinder, in mathematics, surface generated by a line moving parallel to a given fixed line and continually intersecting a given fixed curve called the directrix; each line of the family of lines forming the cylinder is called a ruling, or generator. If the directrix is a conic section (e.g., a circle or a parabola), the cylinder is called a quadric cylinder. The commonest type of cylinder is the right circular cylinder, in which the directrix is a circle and the lines forming the cylinder are all perpendicular to the plane of the circle. The solid bounded by a cylindrical surface and two parallel planes intersecting the surface in closed curves is also called a cylinder. The perpendicular distance between the planes is the altitude of the cylinder. The volume of the cylinder is equal to the product of the altitude and the area of the base (the area enclosed by either closed curve).
a machine component with a cylindrical chamber in which a piston or plunger can move, thereby changing the volume of the compartment formed on either side of the piston or plunger.
In a cylinder, the energy of a working substance (steam or a fuel-air mixture), which exerts pressure on the piston, may be converted into the energy of the piston motion, as in the case of heat engines; alternatively, the energy of the piston motion may be converted into the energy of a liquid or gas, as in the case of pumps or compressors. If the compartment formed on one side of the piston is used, the cylinder is sealed at one end by a head cover. However, if the compartments formed on both sides of the piston are used, two head covers are provided, along with a push-rod that connects the piston to a slide block.
In reciprocating hydraulic and pneumatic drives—such as those used in metalcutting machine tools, presses, and hoists—and in certain reciprocating engines, the cylinder is a single component. In multicylinder reciprocating engines—for example, internal-combustion engines—the cylinders are frequently housed together in a cylinder block, where they may be arranged in a line (an in-line engine), at an angle (a V-engine), or opposite one another (an opposed-cylinder engine). In pumps and in rotary variable-speed hydraulic engines, the cylinders are often located in the rotor and are arranged radially or parallel to the axis of the rotor.
N. IA. NIBERG
a body bounded by a closed cylindrical surface and two parallel planes that intersect the cylindrical surface. The two parallel planes are called the bases of the cylinder. If the bases are perpendicular to the elements, the cylinder is a right cylinder. In particular, if the bases are circles, the cylinder is a right circular, or circular, cylinder; such a cylinder is often referred to simply as a cylinder. The volume of a right circular cylinder is V = πr2h, and the lateral area is S = 2πrh, where r is the radius of the base and h is the altitude of the cylinder. [28–1678–1 ]
cylinderThe aggregate of all tracks that reside in the same location on every disk surface. On multiple-platter disks, the cylinder is the sum total of every track with the same track number on every surface. On a floppy disk, a cylinder comprises the top and corresponding bottom track.
When storing data, the operating system fills an entire cylinder before moving to the next one. The access arm remains stationary until all the tracks in the cylinder have been read or written.
|The cylinder is the aggregate of the same track number on every platter used for recording.|