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Rail Vehicle Resistance
The rail vehicle resistance (or train resistance or simply resistance) is the total force necessary to maintain a rail vehicle in motion. This force depends on a number of variables and is of crucial importance for the energy efficiency of the vehicle as it is proportional to the locomotive power consumption. For the speed of the vehicle to remain the same, the locomotive must express the proper tractive force, otherwise the speed of the vehicle will change until this condition is met. Davis equation A number of experimental measurements of the train resistance have shown that this force can be expressed as a quadratic equation with respect to speed as shown below: R=A+BV+CV^2 Where R is the resistance, V is the speed of the rail vehicle and A, B, and C are experimentally determined coefficients. The most well-known of these relations was proposed by Davis W. J. Jr. and is named after him. The Davis equation contains mechanical and aerodynamic contributions to resistance. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SBB Re 450 097 ZKB Nachtnetz
SBB may refer to: Arts and entertainment * SBB (band), a Polish progressive rock band, or their self-titled albums: ** ''SBB'' (1974 album) ** ''SBB'' (1978 album, Amiga) * Seán Bán Breathnach, also known as SBB, Irish TV personality * ''Saas Bahu aur Betiyaan'', a television programme on the Indian channel Aaj Tak * Soldier Boy Ben, a superhero in the third season of the television series ''The Boys'' Companies * Swiss Federal Railways () * Serbia Broadband (, ), a cable television and broadband internet service provider in Serbia Technology * Solid bleached board, a paperboard grade * Storage Building Block, an individual tape or disk drive component used in a computer data storage array or library * SwiftBroadband, a satellite-based communication network for aircraft * Screened Bottom Board, also known as Open Mesh Floor, a device used to protect beehives from ''Varroa destructor'' mites Others * Saxon Climbers' Federation (), now part of the German Alpine Club * B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Track Gradient
Track or Tracks may refer to: Routes or imprints * Ancient trackway, any track or trail whose origin is lost in antiquity * Animal track, imprints left on surfaces that an animal walks across * Desire path, a line worn by people taking the shortest/most convenient route across fields, parks or woods * Forest track, a track (unpaved road) or trail through a forest * Fossil trackway, a type of trace fossil, usually preserving a line of animal footprints * Trackway, an ancient route of travel or track used by animals * Trail * Vineyard track, a land estate (defined by law) meant for the growing of vine grapes Arts, entertainment, and media Films * ''Tracks'' (1922 film), an American silent Western film * ''Tracks'' (1976 film), an American film starring Dennis Hopper * ''Tracks'' (2003 film), an animated short film * ''Tracks'' (2013 film), an Australian film starring Mia Wasikowska * ''The Track'' (film), a 1975 French thriller–drama film Literature * ''Tracks'' (novel), wr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooling
Cooling is removal of heat, usually resulting in a lower temperature and/or Phase transition, phase change. Temperature lowering achieved by any other means may also be called cooling. The Heat transfer, transfer of Internal energy, thermal energy may occur via thermal radiation, heat conduction or convection. Examples can be as simple as reducing temperature of a coffee. Devices *Coolant *Cooling towers, as used in large industrial plants and power stations *Daytime passive radiative cooler *Evaporative cooler *Heat exchanger *Heat pipe *Heat sink *HVAC (Heating, Ventilation and Air Conditioning) *Intercooler *Radiative cooling in Heat shields *Radiators in automobiles *Pumpable ice technology *Thermoelectric cooling *Vortex tube, as used in industrial spot cooling See also * Computer cooling * Refridgeration References External links * {{Authority control Heating, ventilation, and air conditioning Broad-concept articles Cooling technology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Momentum
In Newtonian mechanics, momentum (: momenta or momentums; more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass and is its velocity (also a vector quantity), then the object's momentum (from Latin '' pellere'' "push, drive") is: \mathbf = m \mathbf. In the International System of Units (SI), the unit of measurement of momentum is the kilogram metre per second (kg⋅m/s), which is dimensionally equivalent to the newton-second. Newton's second law of motion states that the rate of change of a body's momentum is equal to the net force acting on it. Momentum depends on the frame of reference, but in any inertial frame of reference, it is a ''conserved'' quantity, meaning that if a closed system is not affected by external forces, its total momentum does not change. Momentum is also conserved in special relativity (with a mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axle
An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearing (mechanical), bearings or Bushing (bearing), bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside a central hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type of axle is referred to as a ''spindle (tool), spindle''. Terminology On cars and trucks, several senses of the word ''axle'' occur in casual usage, referring to the shaft itself, its housing, or simply any transverse pair of wheels. Strictly speaking, a shaft that rotates with the wheel, being either Bolt (fastener), bolted or rotating spline, splined in fixed relation to it, is called an ''axle'' or ''axle shaft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass
Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary particle, elementary particles, theoretically with the same amount of matter, have nonetheless different masses. Mass in modern physics has multiple Mass in special relativity, definitions which are conceptually distinct, but physically equivalent. Mass can be experimentally defined as a measure (mathematics), measure of the body's inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. The object's mass also determines the Force, strength of its gravitational attraction to other bodies. The SI base unit of mass is the kilogram (kg). In physics, mass is Mass versus weight, not the same as weight, even though mass is often determined by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolling Friction
Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation (or movement) of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysteresis losses (see below), and permanent (plastic) deformation of the object or the surface (e.g. soil). Note that the slippage between the wheel and the surface also results in energy dissipation. Although some researchers have included this term in rolling resistance, some suggest that this dissipation term should be treated separately from rolling resistance because it is due to the applied torque to the wheel and the resultant slip between the wheel and ground, which is called slip loss or slip resistance. In addition, only the so-called slip resistance involves friction, therefore the name "rolling frict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bearing (mechanical)
A ball bearing A bearing is a machine element that constrains relative motion to only the desired motion and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or the directions of the loads (forces) applied to the parts. The term "bearing" is derived from the verb " to bear"; a bearing being a machine element that allows one part to bear (i.e., to support) another. The simplest bearings are bearing surfaces, cut or formed into a part, with varying degrees of control over the form, size, roughness, and location of the surface. Other bearings are separate devices installed into a machine or mach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Energy
In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Robert and Halliday, David (1960) ''Physics'', Section 7-5, Wiley International Edition The kinetic energy of an object is equal to the work, or force ( F) in the direction of motion times its displacement ( s), needed to accelerate the object from rest to its given speed. The same amount of work is done by the object when decelerating from its current speed to a state of rest. The SI unit of energy is the joule, while the English unit of energy is the foot-pound. In relativistic mechanics, \fracmv^2 is a good approximation of kinetic energy only when ''v'' is much less than the speed of light. History and etymology The adjective ''kinetic'' has its roots in the Greek word κίνησις ''kinesis'', meaning "motion". The dichoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potential Energy
In physics, potential energy is the energy of an object or system due to the body's position relative to other objects, or the configuration of its particles. The energy is equal to the work done against any restoring forces, such as gravity or those in a spring. The term ''potential energy'' was introduced by the 19th-century Scottish engineer and physicist William Rankine, although it has links to the ancient Greek philosopher Aristotle's concept of Potentiality and Actuality, ''potentiality''. Common types of potential energy include gravitational potential energy, the elastic potential energy of a deformed spring, and the electric potential energy of an electric charge and an electric field. The unit for energy in the International System of Units (SI) is the joule (symbol J). Potential energy is associated with forces that act on a body in a way that the total Work (physics), work done by these forces on the body depends only on the initial and final positions of the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Energy
In physical sciences, mechanical energy is the sum of macroscopic potential and kinetic energies. The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is constant. If an object moves in the opposite direction of a conservative net force, the potential energy will increase; and if the speed (not the velocity) of the object changes, the kinetic energy of the object also changes. In all real systems, however, nonconservative forces, such as frictional forces, will be present, but if they are of negligible magnitude, the mechanical energy changes little and its conservation is a useful approximation. In elastic collisions, the kinetic energy is conserved, but in inelastic collisions some mechanical energy may be converted into thermal energy. The equivalence between lost mechanical energy and an increase in temperature was discovered by James Prescott Joule. Many devices are us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Work (physics)
In science, work is the energy transferred to or from an Physical object, object via the application of force along a Displacement (vector), displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the Product (mathematics), product of the force strength and the distance traveled. A force is said to do ''positive work'' if it has a component in the direction of the displacement of the point of application. A force does ''negative work'' if it has a component opposite to the direction of the displacement at the point of application of the force. For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is positive, and is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement). If the ball is thrown upwards, the work done by the gravitational force is negative, and is equal to the weight multiplied by the dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
