# cylinder

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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 sectionconic section
or conic
, curve formed by the intersection of a plane and a right circular cone (conical surface). The ordinary conic sections are the circle, the ellipse, the parabola, and the hyperbola.
(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).

## Cylinder

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

## Cylinder

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 ]

## cylinder

[′sil·ən·dər]
(civil engineering)
A steel tube 10-60 inches (25-152 centimeters) in diameter with a wall at least ⅛ inch (3 millimeters) thick that is driven into bedrock, excavated inside, filled with concrete, and used as a pile foundation.
A domed, closed tank for storing hot water to be drawn off at taps. Also known as storage calorifier.
(computer science)
The virtual cylinder represented by the tracks of equal radius of a set of disks on a disk drive.
(engineering)
A container used to hold and transport compressed gas for various pressurized applications.
The piston chamber in a pump from which the liquid is expelled.
(mathematics)
A solid bounded by a cylindrical surface and two parallel planes, or the surface of such a solid.
(mechanical engineering)

## cylinder

In a lock, the cylindrically shaped assembly containing the tumbler mechanism and the keyway, which can be actuated only by the correct keys.

## cylinder

1. Maths a solid consisting of two parallel planes bounded by identical closed curves, usually circles, that are interconnected at every point by a set of parallel lines, usually perpendicular to the planes. Volume base area × length.
2. a surface formed by a line moving round a closed plane curve at a fixed angle to it
3. Engineering the chamber in a reciprocating internal-combustion engine, pump, or compressor within which the piston moves
4. Archaeology a cylindrical seal of stone, clay, or precious stone decorated with linear designs, found in the Middle East and Balkans: dating from about 6000 bc

## cylinder

(storage)
The set of tracks on a multi-headed disk that may be accessed without head movement. That is, the collection of disk tracks which are the same distance from the spindle about which the disks rotate. Each such group forms the shape of a cylinder. Placing data that are likely to be accessed together in cylinders reduces the access significantly as head movement (seeking) is slow compared to disk rotation and switching between heads.

## cylinder

The 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.

Cylinder The cylinder is the aggregate of the same track number on every platter used for recording.
References in periodicals archive ?
That scene is shown on a Neo-Assyrian cylinder seal of about 800 BC.
An emphasis on animals with elaborate horns emerged; some cylinder seals show them standing in parallel rows where the lower animals are depicted larger than those above, an arrangement that may indicate perspective.
The oldest cylinder seal dates from the Early Dynastic Period at the start of the third millennium BC, while the youngest dates from the Persian Period in the second half of the first millennium BC.
On the contrary, this is turned on its head in cylinder seals.
This seems to have changed with the reign of Tudhaliya IV, who requested divine honors for his person while alive; see van den Hout, BiOr 52 (1995): 545-73; Herbordt in The Iconography of Cylinder Seals, 87f
Ruth Mayer-Opificius ("War and Warfare on Cylinder Seals in the Ancient Near East") makes a good argument that the heraldic combat scenes among animals found on many seals are in fact representative of actual war among human antagonists.
Bet Mirsim 1: Cylinder seal with cuneiform signs and hieroglyphics (Rockefeller Museum).
Limited Tenders are invited for Procurement Of Hag Cylinder Seal Kits
Tenders are invited for Procurement Of Boom Cylinder Seal Kits And Other Spares For L And T Make Pc450c-7 Model 3.
One interesting feature on the MC 22 is a reportedly unique hydraulic clamp cylinder design that helps prevent oil leakage from cylinder seal wear.
Tenders are invited for Procurement of Power Cylinder Seal kits & Valve Diaphragms for U-5, 6, 7 and WTP-II.
One is his identification of the horned animals on the Uruk-period cylinder seal in figure 38 as "bulls.

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