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see English units of measurementEnglish units of measurement,
principal system of weights and measures used in a few nations, the only major industrial one being the United States. It actually consists of two related systems—the U.S.
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(also rod cell), a photoreceptor of the human and lower vertebrate eye. The rod cells respond to faint light. They and the cone cells are located in the outermost part of the retina. The cells consist of a basal synapse (connected with deeper-lying retinal cells), the nucleus, an internal segment containing ergastoplasm, the myoid (a contractile element of the rod cells), the ellipsoid (a mass of mitochondria), and an external segment made up of disks. A connective fiber with nine pairs of threads typical of cilia and departing from a pair of centrioles unites the internal and external segments. The disks of the outer segment, which are composed partly of visual pigment, are formed by an invagination of the cytoplasmic membrane. At the retinal periphery, there are more rod cells than cone cells. The retinas of nocturnal and crepuscular animals contain only rods.


Vinnikov, la. A. Tsitologicheskie i molekuliarnye osnovy retseptsii. Leningrad, 1971.




in the theory of oscillations, an elastic solid body whose length greatly exceeds its transverse dimensions. When a rod is excited, for example, by an impact, free oscillations arise in the rod. The oscillatory displacements of the particles of the rod may be directed either along the rod’s axis—longitudinal oscillations—or perpendicular to the axis—torsional and flexural oscillations. For torsional oscillations, any cross section of the rod is twisted with respect to an adjacent cross section. For flexural oscillations, the points of the axis of the rod are displaced in a transverse direction, and fibers parallel to and lying on various sides of the axis undergo tensile and compressive strains.

Any oscillation of a rod may be represented as the sum of the simplest sinusoidals of the various types of natural oscillations in the rod. The frequencies f of the oscillations depend on the length l of the rod, the density p of the material, the shape and area S of the cross section, the elastic reaction to the given type of deformation, and the conditions of attachment of the rod’s ends. For example, for longitudinal oscillations of a free rod,

where E is Young’s modulus and n is an integer corresponding to the number of the harmonic component. For torsional oscillations of a round free rod,

where G is the shear modulus. In the case of flexural oscillations, the natural frequencies do not form a harmonic series, since the rate of propagation of flexural waves is dependent on frequency. For a rod secured at both ends,

where I is the moment of inertia of the cross section with respect to a neutral axis of the rod and the coefficient αn assumes the values α1 = 4.73, α2 = 7.85,. . . The form of the free oscillations of the rod depends on which of the free oscillations are found in the spectrum; this, in turn, is determined by the method of excitation.

Under the action of a sinusoidal driving force the rod oscillates at the frequency of the force f (forced oscillations). When the frequency of the force coincides with one of the rod’s natural frequencies, the phenomenon of resonance occurs.

The practical importance of oscillations of a rod is varied. Any beam in a structural design may be considered as a rod on whose natural frequencies the strength of the structure depends. Dangerous oscillations arising along a ship’s length because of an engine imbalance may be considered as oscillations of a rod. Rods are used in some musical instruments, such as xylophones. A tuning fork is a curved rod with two free ends.


Morse, P. Kolebaniia i zvuk. Moscow-Leningrad, 1949. (Translated from English.)
Strutt, J. W. (Lord Rayleigh). Teoriia zvuka, 2nd ed., vol. 1. Moscow, 1955. (Translated from English.)


(design engineering)
A bar whose end is slotted, tapered, or screwed for the attachment of a drill bit.
A thin, round bar of metal or wood.
A rodlike sedimentary particle characterized by a width-length ratio less than 2/3 and a thickness-width ratio more than 2/3. Also known as roller.
One of the rod-shaped sensory bodies in the retina which are sensitive to dim light.
A relatively long and slender body of material used in, or in conjunction with, a nuclear reactor; may contain fuel, absorber, or fertile material or other material in which activation or transmutation is desired.


1. In plastering, a straightedge, usually of wood, for leveling the face of a wall.
2. A solid (metal, wood, or plastic) product that is long in relation to its cross section.

straightedge, rod

1. A rigid, straight piece of wood or metal used to strike off a concrete, mortared, or plastered surface; a screed, 2.
2. A long piece of seasoned, planed wood having straight, parallel edges; used in construction to lay out straight lines and to align framing.


wand or staff carried as a symbol of office and authority. [Western Culture: Misc.]


1. a straight slender shoot, stem, or cane of a woody plant
2. See fishing rod
a. a unit of length equal to 5½ yards
b. a unit of square measure equal to 30¼ square yards
4. a metal shaft that transmits power in axial reciprocating motion
5. any of the elongated cylindrical cells in the retina of the eye, containing the visual purple (rhodopsin), which are sensitive to dim light but not to colour
6. short for hot rod
References in periodicals archive ?
Each servo-pneumatic axis consists of: rodless pneumatic cylinder type DGPIL-25-600 (Festo) with integral feedback transducer (built-in Temposomc encoders for continual positioning feedback to the master control unit), 5/3 servopneumatic valve (directional proportional control valve) type MPYE-5-1/8-HF-010B (Festo), axis interface type SPC-AIF, positioning axis sub-controller type SPC-200 (the use of a sub-controller card permits control of up to four axes) and Ethernet/Can Bus interface (Festo).
Hunter's new HLM Series represents a proprietary new concept in automated matchplate molding technology: combining and integrating magnetically coupled rodless cylinders and linear bearings (for movements of the squeeze platen, cope flask, sand measuring hopper and other components) are an industry first.
Figure 1 represents the layout of one axis which comprises the linear drive (1) which essentially is a rodless pneumatic cylinder of DGP-X type.
Some years ago, Tol-O-Matic developed a system called PrecisionAire, which used a magnetic particle brake to help control the motion of a rodless cylinder.
Although there are various methods of achieving high speed linear motion, including motor driven rack and pinion and belt drive systems or rodless pneumatic cylinders, one of the most efficient and flexible mechanisms for high speed assembly of small parts is the linear motion (LM) guide and ballscrew drives.
The Ultran slide, which provides high load carrying capabilities within an Ultran rodless cylinder, is now available in a 1 1/16 16-in.
Cases are fed into and out of the elevator by rodless cylinder pushers.
Bimba's product line has expanded over the years to include Space-Saving Flat-Cylinders, Roundline NFPA-Interchangeable Double-Wall Cylinders, Flow Controls, Pneu-Turn Rotary Actuators, Linear Thrusters, Ultran Rodless Cylinder, Position Feedback Cylinders, ISO Cylinders, and EF1 Aluminum-Extruded Body Cylinders.
combines and integrates magnetically coupled rodless cylinders and linear bearings for movements of the squeeze platen, cope flask, sand measuring hopper and other components.
HOERBIGER ORIGA has extended its Origa System Plus (OSP-P) programme of rodless cylinders with a new guidance component designed to withstand the heaviest loads.
Engineers at the two companies made the decision to use Norgren's V22 Fieldbus II pneumatic valve systems and Lintra rodless cylinders.
Rodless actuators guide and support the load with a carriage which moves along the actuator body.