1.
Hydraulics
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Hydraulics is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids or fluids. At a very basic level, hydraulics is the version of pneumatics. Fluid mechanics provides the foundation for hydraulics, which focuses on the applied engineering using the properties of fluids. In fluid power, hydraulics are used for the generation, control, hydraulic topics range through some parts of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluidics and fluid control circuitry, pumps. The principles of hydraulics are in use naturally in the body within the heart. Free surface hydraulics is the branch of hydraulics dealing with surface flow, such as occurring in rivers, canals, lakes, estuaries. Its sub-field open channel flow studies the flow in open channels, the word hydraulics originates from the Greek word ὑδραυλικός which in turn originates from ὕδωρ and αὐλός. Early uses of water power date back to Mesopotamia and ancient Egypt, other early examples of water power include the Qanat system in ancient Persia and the Turpan water system in ancient Central Asia. The Greeks constructed sophisticated water and hydraulic power systems, an example is the construction by Eupalinos, under a public contract, of a watering channel for Samos, the Tunnel of Eupalinos. An early example of the usage of hydraulic wheel, probably the earliest in Europe, is the Perachora wheel, notable is the construction of the first hydraulic automata by Ctesibius and Hero of Alexandria. Hero describes a number of working machines using hydraulic power, such as the force pump, in ancient China there was Sunshu Ao, Ximen Bao, Du Shi, Zhang Heng, and Ma Jun, while medieval China had Su Song and Shen Kuo. Du Shi employed a waterwheel to power the bellows of a blast furnace producing cast iron, Zhang Heng was the first to employ hydraulics to provide motive power in rotating an armillary sphere for astronomical observation. In ancient Sri Lanka, hydraulics were used in the ancient kingdoms of Anuradhapura. The discovery of the principle of the tower, or valve pit. By the first century AD, several irrigation works had been completed. The coral on the rock at the site includes cisterns for collecting water. They were among the first to use of the siphon to carry water across valleys. They used lead widely in plumbing systems for domestic and public supply, hydraulic mining was used in the gold-fields of northern Spain, which was conquered by Augustus in 25 BC
2.
Damping
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If a frictional force proportional to the velocity is also present, the harmonic oscillator is described as a damped oscillator. Depending on the coefficient, the system can, Oscillate with a frequency lower than in the non-damped case. Decay to the position, without oscillations. The boundary solution between an underdamped oscillator and an overdamped oscillator occurs at a value of the friction coefficient and is called critically damped. If an external time dependent force is present, the oscillator is described as a driven oscillator. Mechanical examples include pendulums, masses connected to springs, and acoustical systems, other analogous systems include electrical harmonic oscillators such as RLC circuits. The harmonic oscillator model is important in physics, because any mass subject to a force in stable equilibrium acts as a harmonic oscillator for small vibrations. Harmonic oscillators occur widely in nature and are exploited in many devices, such as clocks. They are the source of virtually all sinusoidal vibrations and waves, a simple harmonic oscillator is an oscillator that is neither driven nor damped. It consists of a m, which experiences a single force, F, which pulls the mass in the direction of the point x=0 and depends only on the masss position x. Balance of forces for the system is F = m a = m d 2 x d t 2 = m x ¨ = − k x. Solving this differential equation, we find that the motion is described by the function x = A cos , the motion is periodic, repeating itself in a sinusoidal fashion with constant amplitude, A. The position at a time t also depends on the phase, φ. The period and frequency are determined by the size of the mass m, the velocity and acceleration of a simple harmonic oscillator oscillate with the same frequency as the position but with shifted phases. The velocity is maximum for zero displacement, while the acceleration is in the direction as the displacement. The potential energy stored in a harmonic oscillator at position x is U =12 k x 2. In real oscillators, friction, or damping, slows the motion of the system, due to frictional force, the velocity decreases in proportion to the acting frictional force. While simple harmonic motion oscillates with only the force acting on the system
3.
Kinetic energy
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In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes, the same amount of work is done by the body in decelerating from its current speed to a state of rest. In classical mechanics, the energy of a non-rotating object of mass m traveling at a speed v is 12 m v 2. In relativistic mechanics, this is an approximation only when v is much less than the speed of light. The standard unit of energy is the joule. The adjective kinetic has its roots in the Greek word κίνησις kinesis, the dichotomy between kinetic energy and potential energy can be traced back to Aristotles concepts of actuality and potentiality. The principle in classical mechanics that E ∝ mv2 was first developed by Gottfried Leibniz and Johann Bernoulli, Willem s Gravesande of the Netherlands provided experimental evidence of this relationship. By dropping weights from different heights into a block of clay, Émilie du Châtelet recognized the implications of the experiment and published an explanation. The terms kinetic energy and work in their present scientific meanings date back to the mid-19th century, early understandings of these ideas can be attributed to Gaspard-Gustave Coriolis, who in 1829 published the paper titled Du Calcul de lEffet des Machines outlining the mathematics of kinetic energy. William Thomson, later Lord Kelvin, is given the credit for coining the term kinetic energy c, energy occurs in many forms, including chemical energy, thermal energy, electromagnetic radiation, gravitational energy, electric energy, elastic energy, nuclear energy, and rest energy. These can be categorized in two classes, potential energy and kinetic energy. Kinetic energy is the movement energy of an object, Kinetic energy can be transferred between objects and transformed into other kinds of energy. Kinetic energy may be best understood by examples that demonstrate how it is transformed to, for example, a cyclist uses chemical energy provided by food to accelerate a bicycle to a chosen speed. On a level surface, this speed can be maintained without further work, except to overcome air resistance, the chemical energy has been converted into kinetic energy, the energy of motion, but the process is not completely efficient and produces heat within the cyclist. The kinetic energy in the moving cyclist and the bicycle can be converted to other forms, for example, the cyclist could encounter a hill just high enough to coast up, so that the bicycle comes to a complete halt at the top. The kinetic energy has now largely converted to gravitational potential energy that can be released by freewheeling down the other side of the hill. Since the bicycle lost some of its energy to friction, it never regains all of its speed without additional pedaling, the energy is not destroyed, it has only been converted to another form by friction
4.
Thermal energy
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In thermodynamics, thermal energy refers to the internal energy present in a system due to its temperature. Heat is energy transferred spontaneously from a hotter to a system or body. Heat is energy in transfer, not a property of the system, on the other hand, internal energy is a property of a system. The internal energy of a gas can in this sense be regarded as thermal energy. In this case, however, thermal energy and internal energy are identical, systems that are more complex than ideal gases can undergo phase transitions. Phase transitions can change the energy of the system without changing its temperature. Therefore, the thermal energy cannot be defined solely by the temperature, for these reasons, the concept of the thermal energy of a system is ill-defined and is not used in thermodynamics. In an 1847 lecture entitled On Matter, Living Force, and Heat, James Prescott Joule characterized various terms that are related to thermal energy. He identified the terms latent heat and sensible heat as forms of heat each effecting distinct physical phenomena, namely the potential and kinetic energy of particles, Heat transfer Ocean thermal energy conversion Thermal science Example of incorrect use of heat and thermal energy
5.
Dashpot
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A dashpot is a mechanical device, a damper which resists motion via viscous friction. The resulting force is proportional to the velocity, but acts in the direction, slowing the motion. It is commonly used in conjunction with a spring, the process and instrumentation diagram symbol for a dashpot is. Two common types of dashpots exist - linear and rotary, linear dashpots are generally specified by stroke and damping coefficient. Rotary dashpots will have damping coefficients in torque per angular velocity, a less common type of dashpot is an eddy current damper, which uses a large magnet inside a tube constructed of a non-magnetic but conducting material. Like a common viscous damper, the eddy current damper produces a force proportional to velocity. Dashpots frequently use a mechanical bypass to permit fast unrestricted motion in one direction. This permits, for example, a door to be opened quickly without added resistance, for hydraulic dashpots this unrestricted motion is accomplished using a one-way check-valve that allows fluid to bypass the dashpot fluid constriction. Non-hydraulic dashpots may use a gear to permit free motion in one direction. A dashpot is a component in a door closer to prevent it from slamming shut. A spring applies force to close the door, and the dashpot forces fluid to flow through an orifice between reservoirs, which slows the motion of the door. Consumer electronics often use dashpots where it is undesirable for an access door or control panel to suddenly pop open when the door latch is released. The dashpot provides a steady, gentle motion until the door has fully opened. Dashpots are commonly used in dampers and shock absorbers, the hydraulic cylinder in an automobile shock absorber is a dashpot. They are also used on carburetors, where the return of the lever is cushioned just before the throttle fully closes. The British SU carburettors main piston carries a stepped needle and this needle is held in the fuel flow orifice. The manifold vacuum causes this piston to rise allowing more fuel into the airflow, the SUs dashpot has a fixed hydraulic piston, damping the main piston as it moves upward. A valve in the piston disables the damping as the piston returns
6.
Pneumatics
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Pneumatics is a branch of engineering that makes use of gas or pressurized air. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases, a centrally located and electrically powered compressor powers cylinders, air motors, and other pneumatic devices. A pneumatic system controlled through manual or automatic solenoid valves is selected when it provides a lower cost, more flexible, pneumatics also has applications in dentistry, construction, mining, and other areas. Pneumatic systems in fixed installations, such as factories, use compressed air because a sustainable supply can be made by compressing atmospheric air, the air usually has moisture removed, and a small quantity of oil is added at the compressor to prevent corrosion and lubricate mechanical components. Factory-plumbed pneumatic-power users need not worry about poisonous leakage, as the gas is usually just air, smaller or stand-alone systems can use other compressed gases that present an asphyxiation hazard, such as nitrogen—often referred to as OFN when supplied in cylinders. Any compressed gas other than air is an asphyxiation hazard—including nitrogen, compressed oxygen would not asphyxiate, but is not used in pneumatically-powered devices because it is a fire hazard, more expensive, and offers no performance advantage over air. Carbon dioxide is an asphyxiant and can be a hazard if vented improperly. The origins of pneumatics can be traced back to the first century when ancient Greek mathematician Hero of Alexandria wrote about his inventions powered by steam or the wind, german physicist Otto von Guericke went a little further. He invented the pump, a device that can draw out air or gas from the attached vessel. He demonstrated the vacuum pump to separate the pairs of copper hemispheres using air pressures, the field of pneumatics has changed considerably over the years. It has moved from small handheld devices to large machines with multiple parts that serve different functions, both pneumatics and hydraulics are applications of fluid power. Pneumatics uses an easily compressible gas such as air or a suitable pure gas—while hydraulics uses relatively incompressible liquid media such as oil, most industrial pneumatic applications use pressures of about 80 to 100 pounds per square inch. Hydraulics applications commonly use from 1,000 to 5,000 psi, simplicity of design and control—Machines are easily designed using standard cylinders and other components, and operate via simple on-off control. Reliability—Pneumatic systems generally have long operating lives and require little maintenance, because gas is compressible, equipment is less subject to shock damage. Gas absorbs excessive force, whereas fluid in hydraulics directly transfers force, compressed gas can be stored, so machines still run for a while if electrical power is lost. Safety—There is a low chance of fire compared to hydraulic oil. Newer machines are usually overload safe, liquid does not absorb any of the supplied energy. Capable of moving much higher loads and providing much higher due to the incompressibility
7.
Hydraulic cylinder
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A hydraulic cylinder is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in construction equipment, manufacturing machinery, Hydraulic cylinders get their power from pressurized hydraulic fluid, which is typically oil. The hydraulic cylinder consists of a barrel, in which a piston connected to a piston rod moves back. The barrel is closed on one end by the cylinder bottom, the piston has sliding rings and seals. The piston divides the inside of the cylinder into two chambers, the chamber and the piston rod side chamber. Flanges, trunnions, clevises, Lugs are common cylinder mounting options, the piston rod also has mounting attachments to connect the cylinder to the object or machine component that it is pushing / pulling. A hydraulic cylinder is the actuator or motor side of this system, the generator side of the hydraulic system is the hydraulic pump which brings in a fixed or regulated flow of oil to the hydraulic cylinder, to move the piston. The piston pushes the oil in the chamber back to the reservoir. The cylinder rod reduces the area of the piston and reduces the force that can be applied for the retraction stroke. For double-acting, double-rod cylinders, when the surface area is equally covered by a rod of equal size on both sides of the head, there is no force difference. Such cylinders typically have their cylinder body affixed to a stationary mount, a hydraulic cylinder consists of the following parts, The main function of cylinder body is to hold cylinder pressure. The cylinder barrel is made from a seamless tube. The cylinder barrel is ground and/or honed internally with a surface finish of 4 to 16 microinch. The piston reciprocates in the cylinder, the main function of the cap is to enclose the pressure chamber at one end. The cap is connected to the body by means of welding, threading, bolts, caps also perform as cylinder mounting components. Cap size is determined based on the bending stress, a static seal / o-ring is used in between cap and barrel. The main function of the head is to enclose the chamber from the other end. The head contains an integrated rod sealing arrangement or the option to accept a seal gland, the head is connected to the body by means of threading, bolts, or tie rod
8.
Hydraulic fluid
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Hydraulic fluid, also called hydraulic liquid, are the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on oil or water. Hydraulic systems like the mentioned above will work most efficiently if the hydraulic fluid used has zero compressibility. The primary function of a fluid is to convey power. In use, however, there are other important functions of fluid such as protection of the hydraulic machine components. Today most hydraulic fluids are based on mineral oil base stocks, natural oils such as rapeseed are used as base stocks for fluids where biodegradability and renewable sources are considered important. Other base stocks are used for specialty applications, such as for fire resistance, some examples include, glycol, esters, organophosphate ester, polyalphaolefin, propylene glycol, and silicone oils. NaK-77, an alloy of sodium-potassium, can be used as a hydraulic fluid in high-temperature and high-radiation environments. Its bulk modulus at 1000 °F is 310,000 psi and its lubricity is poor, so positive-displacement pumps are unsuitable and centrifugal pumps have to be used. Addition of caesium shifts the temperature range to -95 to 1300 °F. The NaK-77 alloy was tested in hydraulic and fluidic systems for the Supersonic Low Altitude Missile, environmentally sensitive applications may benefit from using biodegradable hydraulic fluids based upon rapeseed vegetable oil when there is the risk of an oil spill from a ruptured oil line. Typically these oils are available as ISO32, ISO46, ASTM standards ASTM-D-6006, Guide for Assessing Biodegradability of Hydraulic Fluids and ASTM-D-6046, Standard Classification of Hydraulic Fluids for Environmental Impact are relevant. Brake fluid is a subtype of hydraulic fluid with high boiling point, under the heat of braking, both free water and water vapor in a braking system can boil into a compressible vapor, resulting in brake failure. Glycol-ether based fluids are hygroscopic, and absorbed moisture will greatly reduce the point over time. Mineral oil and silicone based fluids are not hygroscopic, power steering fluid is a subtype of hydraulic fluid. Most are mineral oil or silicone based fluids, while some use automatic transmission fluid, use of the wrong type of fluid can lead to failure of the power steering pump. Fire resistance is a property available with specialized fluids, water-gycol and polyol-ester are some of these specialized fluids that contain excellent thermal and hydrolitic properties, which aid in fire resistance. The hydraulic actuators are controlled by valves, these in turn are operated directly by input from the aircrew or by computers obeying control laws, Hydraulic power is used for other purposes
9.
Pneumatic cylinder
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Pneumatic cylinder are mechanical devices which use the power of compressed gas to produce a force in a reciprocating linear motion. Like hydraulic cylinders, something forces a piston to move in the desired direction, the piston is a disc or cylinder, and the piston rod transfers the force it develops to the object to be moved. Engineers sometimes prefer to use pneumatics because they are quieter, cleaner, because the operating fluid is a gas, leakage from a pneumatic cylinder will not drip out and contaminate the surroundings, making pneumatics more desirable where cleanliness is a requirement. For example, in the puppets of the Disney Tiki Room. Once actuated, compressed air enters into the tube at one end of the piston and, hence, one major issue engineers come across working with pneumatic cylinders has to do with the compressibility of a gas. Many studies have been completed on how the precision of a cylinder can be affected as the load acting on the cylinder tries to further compress the gas used. Under a vertical load, a case where the cylinder takes on the full load, Pneumatic systems are often found in settings where even rare and brief system failure is unacceptable. In such situations locks can sometimes serve as a safety mechanism in case of loss of air supply and, leakage of air from the input or output reduces the pressure and so the desired output. Although pneumatic cylinders will vary in appearance, size and function, however, there are also numerous other types of pneumatic cylinder available, many of which are designed to fulfill specific and specialized functions. Single-acting cylinders use the pressure imparted by compressed air to create a force in one direction. More often than not, this type of cylinder has limited extension due to the space the compressed spring takes up and they have two ports to allow air in, one for outstroke and one for instroke. Stroke length for this design is not limited, however, the rod is more vulnerable to buckling and bending. Additional calculations should be performed as well, telescoping cylinders, also known as telescopic cylinders can be either single or double-acting. The telescoping cylinder incorporates a piston rod nested within a series of stages of increasing diameter. Upon actuation, the rod and each succeeding stage telescopes out as a segmented piston. The main benefit of this design is the allowance for a longer stroke than would be achieved with a single-stage cylinder of the same collapsed length. One cited drawback to telescoping cylinders is the potential for piston flexion due to the segmented piston design. Consequently, telescoping cylinders are primarily utilized in applications where the piston bears minimal side loading, cushion end air cylinders, cylinders with regulated air exhaust to avoid impacts between the piston rod and the cylinder end cover
10.
Electromagnetism
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Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles. The electromagnetic force usually exhibits electromagnetic fields such as fields, magnetic fields. The other three fundamental interactions are the interaction, the weak interaction, and gravitation. The word electromagnetism is a form of two Greek terms, ἤλεκτρον, ēlektron, amber, and μαγνῆτις λίθος magnētis lithos, which means magnesian stone. The electromagnetic force plays a role in determining the internal properties of most objects encountered in daily life. Ordinary matter takes its form as a result of forces between individual atoms and molecules in matter, and is a manifestation of the electromagnetic force. Electrons are bound by the force to atomic nuclei, and their orbital shapes. The electromagnetic force governs the processes involved in chemistry, which arise from interactions between the electrons of neighboring atoms, there are numerous mathematical descriptions of the electromagnetic field. In classical electrodynamics, electric fields are described as electric potential, although electromagnetism is considered one of the four fundamental forces, at high energy the weak force and electromagnetic force are unified as a single electroweak force. In the history of the universe, during the epoch the unified force broke into the two separate forces as the universe cooled. Originally, electricity and magnetism were considered to be two separate forces, Magnetic poles attract or repel one another in a manner similar to positive and negative charges and always exist as pairs, every north pole is yoked to a south pole. An electric current inside a wire creates a corresponding magnetic field outside the wire. Its direction depends on the direction of the current in the wire. A current is induced in a loop of wire when it is moved toward or away from a field, or a magnet is moved towards or away from it. While preparing for a lecture on 21 April 1820, Hans Christian Ørsted made a surprising observation. As he was setting up his materials, he noticed a compass needle deflected away from north when the electric current from the battery he was using was switched on. At the time of discovery, Ørsted did not suggest any explanation of the phenomenon. However, three later he began more intensive investigations
11.
Suspension (vehicle)
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This article is primarily about four-wheeled vehicle suspension. For information on two-wheeled vehicles suspensions see the motorcycle suspension, motorcycle fork, bicycle suspension, Suspension is the system of tires, tire air, springs, shock absorbers and linkages that connects a vehicle to its wheels and allows relative motion between the two. Suspension systems must support both roadholding/handling and ride quality, which are at odds with each other, the tuning of suspensions involves finding the right compromise. The suspension also protects the vehicle itself and any cargo or luggage from damage, the design of front and rear suspension of a car may be different. An early form of suspension on ox-drawn carts had the swing on iron chains attached to the wheeled frame of the carriage. This system remained the basis for all suspension systems until the turn of the 19th century, no modern automobiles use the strap suspension system. Automobiles were initially developed as self-propelled versions of horse-drawn vehicles, however, horse-drawn vehicles had been designed for relatively slow speeds, and their suspension was not well suited to the higher speeds permitted by the internal combustion engine. The first workable spring-suspension required advanced metallurgical knowledge and skill, within a decade, most British horse carriages were equipped with springs, wooden springs in the case of light one-horse vehicles to avoid taxation, and steel springs in larger vehicles. These were often made of steel and usually took the form of multiple layer leaf springs. Leaf springs have been around since the early Egyptians, ancient military engineers used leaf springs in the form of bows to power their siege engines, with little success at first. The use of springs in catapults was later refined and made to work years later. Springs were not only made of metal, a tree branch could be used as a spring. Horse-drawn carriages and the Ford Model T used this system, and it is used today in larger vehicles. This was the first modern system and, along with advances in the construction of roads. In 1901 Mors of Paris first fitted an automobile with shock absorbers, with the advantage of a damped suspension system on his Mors Machine, Henri Fournier won the prestigious Paris-to-Berlin race on 20 June 1901. Fourniers superior time was 11 hrs 46 min 10 sec, while the best competitor was Léonce Girardot in a Panhard with a time of 12 hrs 15 min 40 sec. Coil springs first appeared on a vehicle in 1906 in the Brush Runabout made by the Brush Motor Company. Today, coil springs are used in most cars, in 1920, Leyland Motors used torsion bars in a suspension system
12.
Automobile handling
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Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, in the automotive industry, handling and braking are the major components of a vehicles active safety, as well as its ability to perform in Auto Racing. The maximum lateral acceleration is sometimes discussed separately as road holding, automobiles driven on public roads whose engineering requirements emphasize handling over comfort and passenger space are named sports cars. The center of mass height, relative to the track, determines load transfer from side to side and this load transfer presents itself in the form of body lean. In unfortunate circumstances, the vehicle may roll over, height of the center of mass relative to the wheelbase determines load transfer between front and rear. The cars momentum acts at its center of mass to tilt the car forward or backward, respectively during braking and acceleration. Since it is only the force that changes and not the location of the center of mass. When a car is braking, the load on the front tires increases. A lower center of mass is a performance advantage of sports cars, compared to sedans. Some cars have body panels made of lightweight materials partly for this reason, body lean can also be controlled by the springs, anti-roll bars or the roll center heights. In steady-state cornering, front-heavy cars tend to understeer and rear-heavy cars to oversteer, the mid-engine design seeks to achieve the ideal center of mass, though front-engine design has the advantage of permitting a more practical engine-passenger-baggage layout. All other parameters being equal, at the hands of an expert driver a neutrally balanced mid-engine car can corner faster, the rearward weight bias preferred by sports and racing cars results from handling effects during the transition from straight-ahead to cornering. However, the force being generated by the rear tires is acting in the opposite torsional sense. For this reason, a car with 50/50 weight distribution will understeer on initial corner entry, to avoid this problem, sports and racing cars often have a more rearward weight distribution. In the case of racing cars, this is typically between 40/60 and 35/65. This gives the front tires an advantage in overcoming the cars moment of inertia, using wheels and tires of different sizes is a lever automakers can use to fine tune the resulting over/understeer characteristics. This increases the time it takes to settle down and follow the steering and it depends on the height and width, and can be approximately calculated by the equation, I = M /12. Greater width, then, though it counteracts center of gravity height, some high performance cars have light materials in their fenders and roofs partly for this reason Unless the vehicle is very short, compared to its height or width, these are about equal
13.
Hysteresis
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Hysteresis is the dependence of the state of a system on its history. For example, a magnet may have more than one possible magnetic moment in a magnetic field. Plots of a component of the moment often form a loop or hysteresis curve. This history dependence is the basis of memory in a disk drive. Hysteresis occurs in ferromagnetic and ferroelectric materials, as well as in the deformation of rubber bands and shape-memory alloys, in natural systems it is often associated with irreversible thermodynamic change such as phase transitions and with internal friction, and dissipation is a common side effect. Hysteresis can be found in physics, chemistry, engineering, biology and economics and it is incorporated in many artificial systems, for example, in thermostats and Schmitt triggers, it prevents unwanted frequent switching. Hysteresis can be a lag between an input and an output that disappears if the input is varied more slowly, this is known as rate-dependent hysteresis. However, phenomena such as the magnetic hysteresis loops are mainly rate-independent, systems with hysteresis are nonlinear, and can be mathematically challenging to model. The term hysteresis is derived from ὑστέρησις, an ancient Greek word meaning deficiency or lagging behind and it was coined around 1890 by Sir James Alfred Ewing to describe the behaviour of magnetic materials. Some early work on describing hysteresis in mechanical systems was performed by James Clerk Maxwell, subsequently, hysteretic models have received significant attention in the works of Ferenc Preisach, Louis Néel and D. H. Everett in connection with magnetism and absorption. A more formal theory of systems with hysteresis was developed in the 1970s by a group of Russian mathematicians led by Mark Krasnoselskii. One type of hysteresis is a lag between input and output. A simple example is a sinusoidal input X that results in a sinusoidal output Y and this kind of hysteresis is often referred to as rate-dependent hysteresis. If the input is reduced to zero, the continues to respond for a finite time. This constitutes a memory of the past, but a limited one because it disappears as the output decays to zero, the phase lag depends on the frequency of the input, and goes to zero as the frequency decreases. When rate-dependent hysteresis is due to effects like friction, it is associated with power loss. Systems with rate-independent hysteresis have a persistent memory of the past that remains after the transients have died out, the future development of such a system depends on the history of states visited, but does not fade as the events recede into the past. If an input variable X cycles from X0 to X1 and back again, the values of Y depend on the path of values that X passes through but not on the speed at which it traverses the path
14.
Unsprung mass
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In a ground vehicle with a suspension, the unsprung mass is the mass of the suspension, wheels or tracks, and other components directly connected to them, rather than supported by the suspension. Unsprung mass includes the mass of such as the wheel axles, wheel bearings, wheel hubs, tires, and a portion of the weight of driveshafts, springs, shock absorbers. If the vehicles brakes are mounted outboard, their mass is considered part of the unsprung mass. The unsprung mass of a wheel controls a trade-off between a wheels bump-following ability and its vibration isolation, bumps and surface imperfections in the road cause tire compression—which induces a force on the unsprung mass. The unsprung mass then responds to this force with movement of its own, for this reason, lighter wheels are sought especially for high-performance applications. For longer bumps that the follow, greater unsprung mass causes more energy to be absorbed by the wheels. The shock absorbers, if any, damp the motion also. So the wheels execute some vibrations after each bump before coming to rest and these cause sustained wheel bounce in subsequent vehicles, enlarging the bumps. High unsprung mass also exacerbates wheel control issues under hard acceleration or braking, as mentioned above, there is a positive effect of unsprung mass. Unsprung mass is largely a function of the design of a vehicles suspension, heavy components such as the differential can be made part of the sprung mass by connecting them directly to the body. Lightweight materials, such as aluminum, plastic, carbon fiber, the term unsprung mass was coined by the mathematician Albert Healey of the Dunlop tyre company. This lecture was published as a 100-page paper, inboard brakes can significantly reduce unsprung mass, but put more load on half axles and universal joints, and require space that may not be easily accommodated. If located next to a differential or transaxle, waste heat from the brakes may overheat the differential or vice versa, particularly in hard use, such as motor racing. They also make anti-dive suspension characteristics harder to achieve as the moment created by the act of braking is not reacted on the suspension arms, the Chapman strut used the driveshafts as suspension arms, thus requiring only the weight of one component rather than two. Scooter-type motorcycles use an integrated drive system that pivots as part of the rear suspension. This arrangement is linked to the use of small wheels
15.
Spring (device)
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A spring is an elastic object used to store mechanical energy. Springs are usually out of spring steel. There are a number of spring designs, in everyday usage the term often refers to coil springs. When a spring is compressed or stretched from its resting position, the rate or spring constant of a spring is the change in the force it exerts, divided by the change in deflection of the spring. That is, it is the gradient of the force versus deflection curve, an extension or compression springs rate is expressed in units of force divided by distance, for example lbf/in or N/m. A torsion spring is a spring that works by twisting, when it is twisted about its axis by an angle, a torsion springs rate is in units of torque divided by angle, such as N·m/rad or ft·lbf/degree. The inverse of spring rate is compliance, that is, if a spring has a rate of 10 N/mm, the stiffness of springs in parallel is additive, as is the compliance of springs in series. Springs are made from a variety of materials, the most common being spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel, some non-ferrous metals are also used including phosphor bronze and titanium for parts requiring corrosion resistance and beryllium copper for springs carrying electrical current. Simple non-coiled springs were used throughout history, e. g. the bow. In the Bronze Age more sophisticated spring devices were used, as shown by the spread of tweezers in many cultures, coiled springs appeared early in the 15th century, in door locks. The first spring powered-clocks appeared in that century and evolved into the first large watches by the 16th century, in 1676 British physicist Robert Hooke discovered Hookes law which states that the force a spring exerts is proportional to its extension. Compression spring – is designed to operate with a compression load, flat spring – this type is made of a flat spring steel. Machined spring – this type of spring is manufactured by machining bar stock with a lathe and/or milling operation rather than a coiling operation, since it is machined, the spring may incorporate features in addition to the elastic element. Machined springs can be made in the load cases of compression/extension, torsion. Serpentine spring - a zig-zag of thick wire - often used in modern upholstery/furniture, the most common types of spring are, Cantilever spring – a spring which is fixed only at one end. Coil spring or helical spring – a spring is of two types, Tension or extension springs are designed to become longer under load and their turns are normally touching in the unloaded position, and they have a hook, eye or some other means of attachment at each end. Compression springs are designed to become shorter when loaded and their turns are not touching in the unloaded position, and they need no attachment points
16.
Coil spring
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They are made of an elastic material formed into the shape of a helix which returns to its natural length when unloaded. Under tension or compression, the material of a coil spring undergoes torsion, the spring characteristics therefore depend on the shear modulus, not Youngs Modulus. A coil spring may also be used as a torsion spring, the material of the spring is thereby subjected to a bending moment, either reducing or increasing the helical radius. In this mode, it is the Youngs Modulus of the material determines the spring characteristics. Metal coil springs are made by winding a wire around a shaped former - a cylinder is used to form cylindrical coil springs, types of coil spring are, Tension/extension coil springs, designed to resist stretching. They usually have a hook or eye form at each end for attachment, compression coil springs, designed to resist being compressed. A typical use for compression coil springs is in car suspension systems, volute springs are used as heavy load compression springs. A strip of plate is rolled into the shape of both a helix and a spiral, when compressed, the strip is stiffer edge-on than a wire coil, but the spiral arrangement allows the turns to overlap rather than bottoming out on each other. Torsion springs, designed to resist twisting actions, often associated to clothes pegs or up-and-over garage doors. Spring Helical Spring by Sándor Kabai at The Wolfram Demonstrations Project, Institute of Spring Technology Spring Manufacturers Institute, tutorial by Dave Silberstein. You Spring From Morning To Night, April 1949, Popular Science article on the basics of steel coil springs manufacturing
17.
Leaf spring
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A leaf spring is a simple form of spring commonly used for the suspension in wheeled vehicles. Originally called a laminated or carriage spring, and sometimes referred to as a spring or cart spring. A leaf spring takes the form of a slender arc-shaped length of spring steel of rectangular cross-section, in the most common configuration, the center of the arc provides location for the axle, while tie holes are provided at either end for attaching to the vehicle body. For very heavy vehicles, a spring can be made from several leaves stacked on top of each other in several layers. Leaf springs can serve locating and to some extent damping as well as springing functions, while the interleaf friction provides a damping action, it is not well controlled and results in stiction in the motion of the suspension. For this reason some manufacturers have used mono-leaf springs, a leaf spring can either be attached directly to the frame at both ends or attached directly at one end, usually the front, with the other end attached through a shackle, a short swinging arm. The shackle takes up the tendency of the spring to elongate when compressed. Some springs terminated in an end, called a spoon end. There were a variety of springs, usually employing the word elliptical. Elliptical or full elliptical leaf springs referred to two circular arcs linked at their tips and this was joined to the frame at the top center of the upper arc, the bottom center was joined to the live suspension components, such as a solid front axle. Additional suspension components, such as trailing arms, would usually be needed for this design and that employed the lower arc, hence its name. As an example of leaf springs, the Ford Model T had multiple leaf springs over its differential that were curved in the shape of a yoke. As a substitute for dampers, some manufacturers laid non-metallic sheets in between the leaves, such as wood. Today leaf springs are used in heavy commercial vehicles such as vans and trucks, SUVs. For heavy vehicles, they have the advantage of spreading the load more widely over the vehicles chassis, whereas coil springs transfer it to a single point. Unlike coil springs, leaf springs also locate the axle, eliminating the need for trailing arms. A further advantage of a leaf spring over a spring is that the end of the leaf spring may be guided along a definite path. A more modern implementation is the leaf spring
18.
Torsion spring
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A torsion spring is a spring that works by torsion or twisting, that is, a flexible elastic object that stores mechanical energy when it is twisted. When it is twisted, it exerts a force in the opposite direction, a torsion bar is a straight bar of metal or rubber that is subjected to twisting about its axis by torque applied at its ends. A more delicate form used in instruments, called a torsion fiber consists of a fiber of silk, glass, or quartz under tension. This terminology can be confusing because in a torsion spring the forces acting on the wire are actually bending stresses. It is analogous to the constant of a linear spring. The negative sign indicates that the direction of the torque is opposite to the direction of twist. Other uses are in the large, coiled torsion springs used to counterbalance the weight of doors. Small, coiled torsion springs are used to operate pop-up doors found on small consumer goods like digital cameras. It absorbs road shocks as the wheel goes over bumps and rough road surfaces, torsion-bar suspensions are used in many modern cars and trucks, as well as military vehicles. The sway bar used in vehicle suspension systems also uses the torsion spring principle. The torsion pendulum used in pendulum clocks is a wheel-shaped weight suspended from its center by a wire torsion spring. The weight rotates about the axis of the spring, twisting it, the force of the spring reverses the direction of rotation, so the wheel oscillates back and forth, driven at the top by the clocks gears. The balance spring or hairspring in mechanical watches is a fine, spiral-shaped torsion spring that pushes the wheel back toward its center position as it rotates back. The balance wheel and spring function similarly to the torsion pendulum above in keeping time for the watch, the DArsonval movement used in mechanical pointer-type meters to measure electric current is a type of torsion balance. A coil of wire attached to the twists in a magnetic field against the resistance of a torsion spring. Hookes law ensures that the angle of the pointer is proportional to the current, a DMD or digital micromirror device chip is at the heart of many video projectors. It uses hundreds of thousands of mirrors on tiny torsion springs fabricated on a silicon surface to reflect light onto the screen. The torsion balance consists of a bar suspended from its middle by a thin fiber, the fiber acts as a very weak torsion spring
19.
Torsion bar suspension
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A torsion bar suspension, also known as a torsion spring suspension, is a general term for any vehicle suspension that uses a torsion bar as its main weight bearing spring. Vertical motion of the causes the bar to twist around its axis and is resisted by the bars torsion resistance. The effective spring rate of the bar is determined by its length, cross section, shape, material, manufacturers change the torsion bar or key to adjust the ride height, usually to compensate for heavier or lighter engines. Over-rotating the torsion bars can cause the suspension to hit the bump-stop prematurely. Aftermarket forged-metal torsion key kits use relocked adjuster keys to prevent over-rotation, the main advantages of a torsion bar suspension are durability, easy adjustability of ride height, and small profile along the width of the vehicle. It takes up less of the interior volume than coil springs. Torsion bars reached the height of their popularity on mass-production road cars in the middle of the 20th century at the time that unitary construction was being adopted. Using MacPherson struts to achieve independent front suspension with coil springs meant providing strong turrets in the structure of the car. A disadvantage is that torsion bars, unlike coil springs, usually provide a progressive spring rate. In most torsion bar systems, ride height may be changed by simply adjusting bolts that connect the torsion bars to the steering knuckles, in most cars with this type of suspension, swapping torsion bars for a different spring rate is usually an easy task. Some vehicles use torsion bars to provide automatic levelling, using a motor to pre-stress the bars to provide resistance to load and, in some cases. Height adjustable suspension has been used to implement a wheel-change mode where the vehicle is raised on three wheels so that the wheel is lifted off the ground without the aid of a jack. Before World War II, the front wheel drive Citroen Traction Avant had independent front torsion bar suspension, the flexibility of the axle beam provided wheel location features like a twist beam axle. The Czechoslovakian Tatra cars designed by Professor Hans Ledwinka in the mid-1930s used all round independent torsion bar suspension, also in the 1930s, prototypes of the first Volkswagen Beetle incorporated torsion bars—especially its transverse mounting style. The system first saw use in the Swedish Stridsvagn L-60 tank of 1934. It was used extensively in European cars Renault, Citroën and Volkswagen, the Packard used torsion bars at both front and rear, and interconnected the front and rear systems to improve ride quality. Morris Minor and Oxford from the late 1940s onwards used a front torsion bar system very similar to the Citroen, the single torsion bar was mounted through the frame sides behind the rear axle and then attached by arms and links to the front side of the spring U-bolt plates. Axle Flex was discontinued for the 1936 model year, the designer of these cars, Alec Issigonis was inspired by the Traction Avants suspension although the Morris cars were rear-wheel drive and used conventional leaf springs for their rear axles
20.
Friction disk shock absorber
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Friction disk shock absorbers or André Hartford dampers were an early form of shock absorber or damper used for car suspension. They were commonly used in the 1930s but were considered obsolete post-war, the friction disk pattern was invented by Truffault, before 1900. These used oiled leather friction surfaces between bronze disks compressed by adjustable conical springs, with the disk pack floating between arms to both chassis and axle, in the distinctive style. From 1904 these were licensed to several makers including Mors, who had first applied shock absorbers to cars, similar dampers were also applied as steering dampers from this early date. The dampers rely, as their name suggests, on the friction within a stack of disks, clamped together with a spring. The friction disk material was usually a disk between the two faces of the steel arms. As for the development of the clutch and brake shoes, the development of these materials was in its infancy. Treated leather had been used for clutches and although it offered good friction behaviour, it was prone to stiction when first moving off, asbestos-based friction materials were sometimes used for racing, in an attempt to keep dampers working correctly even when overheating. The damping force of a shock absorber is adjusted with the central pivot. A star-shaped spring applies a force to the stack of disks, the damping force is roughly proportional to this force and the clamping nut is provided with a pointer arm to indicate the approximate setting. André Hartford dampers were made in four sizes, according to vehicle weight and these were the combination of two disk diameters, 3¼ & 4½ and as either single or multiplate designs. Single dampers had two friction surfaces, an arm on one side was nested between two arms connected to the other. Multiplate dampers had two and three arms on each side, dampers were mounted to the chassis and axle through Silentbloc bushes at each end. Silentbloc bushes were another development of the early 1930s, a rubber bush bonded into a steel tube. These provided the location that accurate suspension required, but reduced vibration and road noise. Many cars used a different design for front and rear, where the arms were rigidly bolted to the chassis. The invention of Georges de Ram, these were a sophisticated and complex pattern. They were only used on vehicles, notably Bugattis
21.
Arrol-Johnston
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Arrol-Johnston was an early Scottish manufacturer of automobiles, which operated from 1896 to 1931 and produced the first automobile manufactured in Britain. The company also developed the worlds first off-road vehicle for the Egyptian government, george Johnston was by training a locomotive engineer from Neilson, Reid and Company Limited of Springburn, Glasgow. Johnston was commissioned by Glasgow Corporation Tramways in 1894 to build an experimental steam-powered tramcar to replace their fleet of horse-drawn trams, during a final test before a Corporation committee, it caught fire and work was abandoned. The first British-built motor car was conceived and by the end of 1895 was ready for financial backing. In the autumn of that year Johnston was joined by Norman Osborne Fulton and his first task was the development of electrical ignition in place of the incandescent platinum tubes of the Daimler engine. In 1895 Johnston formed a joint venture with Sir William Arrol, an engineer of the Forth Bridge to form the Mo-Car Syndicate Limited, which was to produce his car. Sir William was Chairman and Johnston was Managing Director, and the Syndicate included a Mr. Archibald Coats, Sir Williams main interest in the business was as the financial backer. The first Arrol-Johnston car was a six-seater Dogcart, which went into production at a factory at Camlachie, the Dogcart was a wood-bodied vehicle powered by a 10 hp flat-twin horizontally opposed engine with four pistons mounted beneath the floor, which was started by pulling on a rope. The vehicle boasted chain final drive and its high-wheeled, solid-tyred, transmission and brake control levers were mounted close to the drivers right hand. The companys Camlachie premises were destroyed by fire in 1901, in 1902 William Beardmore took the largest single shareholding in the company, creating a captive customer for his iron and steel components. He later became Chairman when A-J became a public company, A-J was restructured financially in 1903. New finance, mainly from Beardmore, became available, Beardmore wishing to help the firm stave off bankruptcy, george Johnston left as a result of a disagreement and founded the All British Car Company, a venture that was to be short-lived. A-J became effectively a wholly owned subsidiary of William Beardmore and Company In 1905 the companys name was changed to the Arrol-Johnston Car Company Ltd. In the same year, the company introduced a 3023cc 12/15hp model of modern appearance. There was also a version of the dogcart, this was an uncouth 16 hp with the centre cylinder being of greater bore than the outer two. A1905 Dogcart with solid disc wheels still survives in Khartoum. In 1906 came the 24/30 hp vertical four of 4654cc, followed in 1907 by the 38/45 hp of 8832 cc, the 12/15 hp twin survived in production until 1909. This was the year that T. C, pullinger joined Arrol-Johnston, he swept out the old range in favour of the new 15·9 hp of 2835cc
22.
Brooklands
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Brooklands was a 2. 75-mile motor racing circuit and aerodrome built near Weybridge in Surrey, England, United Kingdom. It opened in 1907 and was the worlds first purpose-built motor racing circuit as well as one of Britains first airfields, the Brooklands motor circuit was the brainchild of Hugh F. Locke King, and was the first purpose-built banked motor race circuit in the world. Apparently drawing inspiration from the development at Brooklands, the Indianapolis Motor Speedway was built soon afterwards, requirements of speed and spectator visibility led to the Brooklands track being built as a 100 ft wide,2.75 miles long, banked oval. The banking was nearly 30 feet high in places, in addition to the oval, a bisecting Finishing Straight was built, increasing the track length to 3.25 miles, of which 1.25 miles was banked. It could host up to 287,000 spectators in its heyday, owing to the complications of laying tarmacadam on banking, and the expense of laying asphalt, the track was built in uncoated concrete. This led in later years to a bumpy ride, as the surface suffered differential settlement over time. Along the centre of the track ran a black line. By driving over the line, a driver could take the banked corners without having to use the steering wheel. The Brooklands Mountain Circuit was a section of the track giving a lap 1¼ miles long, running from the Fork to the rear of Members Hill. It was created in 1930 using movable barriers, on 28–29 June 1907, eleven days after the circuit opened, it played host to the worlds first 24-hour motor event, with Selwyn Edge leading three specially converted Napier cars around the circuit. A statement of intent had been made in 1906, and Selwyn Edge entered into a training program to prepare for the event. His car,804 was extensively modified, having a fuel tank, bodywork removed. Over 300 red railway lamps were used to light the track during the night, flares were used to mark the upper boundary of the track. Edge drove his car for the duration, with the drivers of the other two cars taking the more familiar shift approach. During the event Edge covered a distance of 1,581.74 mi at an speed of 65.91 mph. Women were not allowed to compete for several years, edges leading driver, was refused entry despite having been the first English-woman to compete in a motor race in 1903, and holding the Ladies World Land Speed Record. Edge completed 2,545 km at an average 106.06 km/h, the first standard race meeting would be held the next week, on 6 July. George E. Stanley broke the record at Brooklands race track on a Singer motorcycle in 1912
23.
World War I
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World War I, also known as the First World War, the Great War, or the War to End All Wars, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history and it was one of the deadliest conflicts in history, and paved the way for major political changes, including revolutions in many of the nations involved. The war drew in all the worlds great powers, assembled in two opposing alliances, the Allies versus the Central Powers of Germany and Austria-Hungary. These alliances were reorganised and expanded as more nations entered the war, Italy, Japan, the trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia. Within weeks, the powers were at war and the conflict soon spread around the world. On 25 July Russia began mobilisation and on 28 July, the Austro-Hungarians declared war on Serbia, Germany presented an ultimatum to Russia to demobilise, and when this was refused, declared war on Russia on 1 August. Germany then invaded neutral Belgium and Luxembourg before moving towards France, after the German march on Paris was halted, what became known as the Western Front settled into a battle of attrition, with a trench line that changed little until 1917. On the Eastern Front, the Russian army was successful against the Austro-Hungarians, in November 1914, the Ottoman Empire joined the Central Powers, opening fronts in the Caucasus, Mesopotamia and the Sinai. In 1915, Italy joined the Allies and Bulgaria joined the Central Powers, Romania joined the Allies in 1916, after a stunning German offensive along the Western Front in the spring of 1918, the Allies rallied and drove back the Germans in a series of successful offensives. By the end of the war or soon after, the German Empire, Russian Empire, Austro-Hungarian Empire, national borders were redrawn, with several independent nations restored or created, and Germanys colonies were parceled out among the victors. During the Paris Peace Conference of 1919, the Big Four imposed their terms in a series of treaties, the League of Nations was formed with the aim of preventing any repetition of such a conflict. This effort failed, and economic depression, renewed nationalism, weakened successor states, and feelings of humiliation eventually contributed to World War II. From the time of its start until the approach of World War II, at the time, it was also sometimes called the war to end war or the war to end all wars due to its then-unparalleled scale and devastation. In Canada, Macleans magazine in October 1914 wrote, Some wars name themselves, during the interwar period, the war was most often called the World War and the Great War in English-speaking countries. Will become the first world war in the sense of the word. These began in 1815, with the Holy Alliance between Prussia, Russia, and Austria, when Germany was united in 1871, Prussia became part of the new German nation. Soon after, in October 1873, German Chancellor Otto von Bismarck negotiated the League of the Three Emperors between the monarchs of Austria-Hungary, Russia and Germany
24.
Lever arm shock absorber
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Lever arm shock absorbers were the first form of hydraulic shock absorber or damper used for car suspension. They appeared in the 1930s and were most commonly used in the 1950s and 1960s, One of the earliest patents for a hydraulic lever arm shock absorber was awarded in 1925 to Georges de Ram, who was already an established maker of friction disk shock absorbers. Hydraulic shock absorbers appeared as a development to replace the previous friction disks and these had, at best, provided a constant damping force, no matter what the size or speed of the suspension movement. With a viscous device using hydraulic oil, the force increased with speed. The first hydraulic shock absorbers were of the rotary vane pattern and these consisted of a cylindrical oil-filled body, bolted to the chassis. A lever arm was attached to the axle and inside the cylinder and this vane had only a small hole in it, through which the hydraulic oil could pass. Resistance to flow through the hole provided the damping effect and these were first developed by Maurice Houdaille around 1906, but remained largely ignored in favour of the simpler friction devices for some years. This type was most common pre-war, although Ferrari continued to use the Houdaille vane-type for Formula One racing cars into the late 1950s, a post-war development was the lever shock absorber. This had a large cast body containing a cylinder and pistons attached to a similar spindle, some used a pair of pistons for bump and rebound, others used a single double-acting piston. Flow of hydraulic oil around the piston took place through valves mounted in the body, separate valves were provided for each direction, giving the useful feature of a different resistance to bump and rebound. These valves were sometimes easily adjustable from outside the damper body, many cars of this period began to use independent front suspension, often a double wishbone. The upper wishbone could conveniently also be used as the lever of the absorber, reducing the mass and bulk of the suspension. The spindle of the shock absorber now became the upper suspension pivot, One of the last mass-production sports cars to still use lever arm shock absorbers was the MG B. This had a lever arm shock absorber as the upper wishbone, a popular handling upgrade in later years was to fit telescopic shock absorbers instead. The lever arm wishbone was still retained, but now as a wishbone with no damping. During the 1960s, the arm was replaced by the telescopic shock absorber. This was encouraged by better roads and motorways, increasing average speeds, the telescopic shock absorber dissipated heat more effectively, owing to its larger working volume of fluid and also the better ratio of surface area to fluid volume
25.
Coilover
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A coilover is an automobile suspension device. Coilover is short for coil spring over shock and it consists of a shock absorber with a coil spring encircling it. The shock absorber and spring are assembled as a prior to installation. This provides damping without torsional loads, some coilovers allow adjustment of ride height and preload, using a simple threaded spring perch similar to a nut. More advanced adjustable coilover systems use a threaded body, along with an adjustable lower mount for ride height adjustment. Stiffness is changed by switching the spring for one with a different spring rate, the coilover style of spring placement is a component of the MacPherson strut suspension system, which uses a design of anti-roll bar as a longitudinal constraint. Coilovers are different from struts or independently mounted shock absorbers, there are two types of coilovers, full coilovers and slip on coilovers
26.
Pounds per square inch
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The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units. Now converting the psi to standard atmospheres,1 atm =101325 Pa =101325 Pa 6894.757293168 Pa / psi ≈14.70 psi Therefore,1 atmosphere is approximately 14.7 pounds per square inch. Pounds per square inch absolute is used to make it clear that the pressure is relative to a rather than the ambient atmospheric pressure. Since atmospheric pressure at sea level is around 14.7 psi, the converse is pounds per square inch gauge or pounds per square inch gage, indicating that the pressure is relative to atmospheric pressure. For example, a bicycle tire pumped up to 65 psi above atmospheric pressure. When gauge pressure is referenced to something other than ambient atmospheric pressure, the kilopound per square inch is a scaled unit derived from psi, equivalent to a thousand psi. Ksi are not widely used for gas pressures and they are mostly used in materials science, where the tensile strength of a material is measured as a large number of psi. The conversion in SI Units is 1 ksi =6.895 MPa, the megapound per square inch is another multiple equal to a million psi. It is used in mechanics for the modulus of the materials. The conversion in SI Units is 1 Mpsi =6.895 GPa, inch of water,0.036 psid Blood pressure – clinically normal human blood pressure,2.32 psig/1.55 psig Natural gas residential piped in for consumer appliance, 4–6 psig. Boost pressure provided by a turbocharger, 6–15 psig NFL football,12. 5–13.5 psig Atmospheric pressure at sea level,14
27.
ThyssenKrupp
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ThyssenKrupp AG /ˈtɪsɛn. krʊp/ is a German multinational conglomerate, based in Duisburg and Essen and divided into 670 subsidiaries worldwide. It is one of the worlds largest steel producers, it was ranked tenth-largest worldwide by revenue in 2015, the company is the result of the 1999 merger of Thyssen AG and Krupp, and now has its operational headquarters in Essen. In addition to production, ThyssenKrupps products range from machines and industrial services to high-speed trains. The subsidiary ThyssenKrupp Marine Systems manufactures frigates, corvettes and submarines for German, ThyssenKrupp has 5,500 employees and generates €1.6 billion in revenue in Spain, where it mainly manufactures elevators. Italy, where the company produces most of its stainless steel, the businesses in those two countries make up 9% of all sales for the company. Construction of the headquarters began in 2007. The first buildings were complete in 2010, the phase of building was completed in June 2015. Situated in the west of Essen, the campus was designed by Chaix & Morel et associeés. Their design was selected for construction in a design competition in 2006. ThyssenKrupp is the result of a merger of two German steel companies, Thyssen AG founded in 1891 under the name Gewerkschaft Deutscher Kaiser, as early as the 1980s, the companies began negotiations on a merger and began closely cooperating in some business areas. In 1997, the companies combined their flat steel activities, with a merger completed in March 1999. Krupp 1811, Friedrich Alfred Krupp establishes a cast steel factory in Essen,1826, After Friedrich Krupps death in 1826, his widow Therese Krupp runs the company together with other relatives and her eldest son Alfred, who was 14 years old at the time. 1833, Krupp manufactures complete rolling machines,1847, Expansion of the railroads increases demand for durable cast steel, triggering the company’s first surge of growth. Supplies include axles, springs and the tires that can withstand increasing speed without cracking. 1859, The Prussian military orders 300 gun barrels, marking development of the second major production segment. 1862, Construction of the first Bessemer steel plant on the continent for mass production of rails, 1864–1872, The company purchases various iron ore mines to avoid dependency on external suppliers. In 1873, Krupp establishes his own shipping company in Rotterdam to transport ore from the Spanish company Orconera Iron Ore Co. in which he owns shares,1872, Alfred Krupp issues a General Directive establishing company hierarchy from foreman to management. Thyssen 1867, Establishment of Thyssen, Fossoul & Co. a company making hoop iron for barrels, crates, baling etc
28.
Multimatic
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Multimatic Inc. is a privately held Canadian corporation supplying engineered components, systems and services to the global automotive industry. Headquartered in Markham, Ontario, Multimatic has manufacturing divisions and engineering facilities in North America, Europe, and Asia, in addition, Multimatic delivers niche vehicle design, development, and production for road and race car applications. Multimatic was ranked 79 on the 2015 Automotive News Top 100 North American Suppliers list, Multimatic engineered and constructed the carbon chassis and suspension systems for the RUF CTR3 and Aston Martin One-77, and is Fords build partner for the 2017 Ford GT. The company has provided engineering input on the Aston Martin V12 Zagato, Aston Martin CC100. Multimatic Motorsports designs, engineers, builds, supports and campaigns racing cars in North America, the company also markets the patented Multimatic DSSV damper through its Dynamic Suspensions brand. DSSV dampers are characterized by the use of valves in place of conventional flexible shims. S. F2000 National Championship from 2011, the Deutsche Tourenwagen Meisterschaft from 2012, Indy Lights from 2015, DSSV dampers were also supplied for Red Bull Racings four consecutive Formula One titles from 2010-2013, and has equipped nearly half the field at the 24 Hours of Le Mans. Official website 2011 Automotive News Top 100 North American Suppliers Automotive News 100 Cool Things Automotive News PACE Awards
29.
Compression (physics)
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It is contrasted with tension or traction, the application of balanced outward forces, and with shearing forces, directed so as to displace layers of the material parallel to each other. The compressive strength of materials and structures is an important engineering consideration, in uniaxial compression the forces are directed along one direction only, so that they act towards decreasing the objects length along that direction. If the stress vector itself is opposite to x, the material is said to be under compression or pure compressive stress along x. In a solid, the amount of compression depends on the direction x. If the stress vector is purely compressive and has the same magnitude for all directions and this is the only type of static compression that liquids and gases can bear. In a mechanical longitudinal wave, or compression wave, the medium is displaced in the waves direction, when put under compression, every material will suffer some deformation, even if imperceptible, that causes the average relative positions of its atoms and molecules to change. The deformation may be permanent, or may be reversed when the compression forces disappear, in the latter case, the deformation gives rise to reaction forces that oppose the compression forces, and may eventually balance them. Liquids and gases cannot bear steady uniaxial or biaxial compression, they will deform promptly and permanently, however they can bear isotropic compression, and may be compressed in other ways momentarily, for instance in a sound wave. The deformation may not be uniform and may not be aligned with the compression forces, what happens in the directions where there is no compression depends on the material. Most materials will expand in those directions, but some special materials will remain unchanged or even contract, by inducing compression, mechanical properties such as compressive strength or modulus of elasticity, can be measured. Compression machines range from small table top systems to ones with over 53 MN capacity. Gases are often stored and shipped in highly compressed form, to save space, slightly compressed air or other gases are also used to fill balloons, rubber boats, and other inflatable structures. Compressed liquids are used in equipment and in fracking. In internal combustion engines the explosive mixture gets compressed before it is ignited, in the Otto cycle, for instance, the second stroke of the piston effects the compression of the charge which has been drawn into the cylinder by the first forward stroke. This compression, moreover, obviates the shock which would otherwise be caused by the admission of the steam for the return stroke. Buckling Container compression test Compression member Compressive strength Longitudinal wave P-wave Rarefaction Strength of materials
30.
Rubber
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Natural rubber, also called India rubber or caoutchouc, as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds, plus water. Malaysia and Indonesia are two of the leading rubber producers, forms of polyisoprene that are used as natural rubbers are classified as elastomers. Currently, rubber is harvested mainly in the form of the latex from the tree or others. The latex is a sticky, milky colloid drawn off by making incisions in the bark, the latex then is refined into rubber ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup, the coagulated lumps are collected and processed into dry forms for marketing. Natural rubber is used extensively in many applications and products, either alone or in combination with other materials, in most of its useful forms, it has a large stretch ratio and high resilience, and is extremely waterproof. The major commercial source of rubber latex is the Pará rubber tree. This species is preferred because it grows well under cultivation, a properly managed tree responds to wounding by producing more latex for several years. Congo rubber, formerly a source of rubber, came from vines in the genus Landolphia. These cannot be cultivated, and the drive to collect latex from wild plants was responsible for many of the atrocities committed under the Congo Free State. The latex exhibits the quality as the natural rubber from rubber trees. In the wild types of dandelion, latex content is low, in Nazi Germany, research projects tried to use dandelions as a base for rubber production, but failed. In collaboration with Continental Tires, IME began a pilot facility, many other plants produce forms of latex rich in isoprene polymers, though not all produce usable forms of polymer as easily as the Pará. Some of them require more processing to produce anything like usable rubber. Some produce other desirable materials, for example gutta-percha and chicle from Manilkara species, the term gum rubber is sometimes applied to the tree-obtained version of natural rubber in order to distinguish it from the synthetic version. The first use of rubber was by the cultures of Mesoamerica. The earliest archeological evidence of the use of latex from the Hevea tree comes the Olmec culture. The Pará rubber tree is indigenous to South America, charles Marie de La Condamine is credited with introducing samples of rubber to the Académie Royale des Sciences of France in 1736
31.
Stretching
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PNF is considered an optimal stretching method when the aim is to increase range of motion, especially as regards short-term changes. Generally an active PNF stretch involves a shortening contraction of the muscle to place the target muscle on stretch. This is followed by a contraction of the target muscle. PNF can be used to supplement daily stretching and to make gains in range of motion – for example. In addition to being safe and time efficient, the rapidly achievable gains in range of motion may also help promote compliance with the exercise, in the early to mid 1900s physiologist Charles Sherrington popularized a model for neuromuscular facilitation and inhibition. This subsequently led Herman Kabat, a neurophysiologist, to develop the clinical PNF stretching technique using natural movement patterns and he believed combinations of movement would be better than the traditional moving of one joint at a time. Initial PNF techniques were used to aid the rehabilitation of clients with spasticity, Kabat started an institute in Washington, DC and by 1951 had two offices in California as well. His assistants Margaret Knott and Dorothy Voss in California, applied PNF to all types of therapeutic exercise, the patterns of movement associated with PNF are composed of multijoint, multiplanar, diagonal, and rotational movements of the extremities, trunk & neck. There are 2 pairs of foundational movements for the extremities, UE D1 flexion & extension. There are also 2 pairs of foundational movements for the extremities, LE D1 flexion & extension. Various PNF stretching techniques based on Kabat’s concept are, Hold Relax, Contract Relax, Contract Relax, Passive placement of the restricted muscle into a position of stretch followed by an isotonic contraction of the restricted muscle. Most isometric contractions in PNF stretching techniques should be held for a minimum of 3 seconds at a sub maximal effort to avoid muscle fatigue and injury. After the contraction period the patient is instructed to relax the muscle that was just contracting. Through Golgi tendon organ, the muscle is relaxed. Hold Relax, Very similar to the Contract Relax technique and this is utilized when the agonist is too weak to activate properly. The patients restricted muscle is put in a position of stretch followed by a contraction of the restricted muscle. After the allotted time the muscle is passively moved to a position of greater stretch. Contraction times and efforts will remain the same as the Contract Relax technique and this technique utilizes the autogenic inhibition, which relaxes a muscle after a sustained contraction has been applied to it for longer than 6 seconds
32.
Bending
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In applied mechanics, bending characterizes the behavior of a slender structural element subjected to an external load applied perpendicularly to a longitudinal axis of the element. The structural element is assumed to be such that at least one of its dimensions is a fraction, typically 1/10 or less. When the length is longer than the width and the thickness. For example, a closet rod sagging under the weight of clothes on clothes hangers is an example of a beam experiencing bending. On the other hand, a shell is a structure of any form where the length. A large diameter, but thin-walled, short tube supported at its ends, in the absence of a qualifier, the term bending is ambiguous because bending can occur locally in all objects. Therefore, to make the usage of the more precise, engineers refer to a specific object such as, the bending of rods, the bending of beams, the bending of plates. A beam deforms and stresses develop inside it when a load is applied on it. In the quasi-static case, the amount of bending deflection and the stresses that develop are assumed not to change over time. In a horizontal beam supported at the ends and loaded downwards in the middle and these last two forces form a couple or moment as they are equal in magnitude and opposite in direction. This bending moment resists the sagging deformation characteristic of a beam experiencing bending, the stress distribution in a beam can be predicted quite accurately when some simplifying assumptions are used. In the Euler–Bernoulli theory of beams, a major assumption is that plane sections remain plane. In other words, any deformation due to shear across the section is not accounted for, also, this linear distribution is only applicable if the maximum stress is less than the yield stress of the material. For stresses that exceed yield, refer to article plastic bending, at yield, the maximum stress experienced in the section is defined as the flexural strength. Simple beam bending is often analyzed with the Euler–Bernoulli beam equation, the conditions for using simple bending theory are, The beam is subject to pure bending. This means that the force is zero, and that no torsional or axial loads are present. The material is isotropic and homogeneous, the beam is initially straight with a cross section that is constant throughout the beam length. The beam has an axis of symmetry in the plane of bending, the proportions of the beam are such that it would fail by bending rather than by crushing, wrinkling or sideways buckling
33.
Steel
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Steel is an alloy of iron and other elements, primarily carbon, that is widely used in construction and other applications because of its high tensile strength and low cost. Steels base metal is iron, which is able to take on two forms, body centered cubic and face centered cubic, depending on its temperature. It is the interaction of those allotropes with the elements, primarily carbon. In the body-centred cubic arrangement, there is an atom in the centre of each cube. Carbon, other elements, and inclusions within iron act as hardening agents that prevent the movement of dislocations that otherwise occur in the lattices of iron atoms. The carbon in steel alloys may contribute up to 2. 1% of its weight. Steels strength compared to pure iron is possible at the expense of irons ductility. With the invention of the Bessemer process in the mid-19th century and this was followed by Siemens-Martin process and then Gilchrist-Thomas process that refined the quality of steel. With their introductions, mild steel replaced wrought iron, further refinements in the process, such as basic oxygen steelmaking, largely replaced earlier methods by further lowering the cost of production and increasing the quality of the product. Today, steel is one of the most common materials in the world and it is a major component in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons. Modern steel is generally identified by various grades defined by assorted standards organizations, the noun steel originates from the Proto-Germanic adjective stakhlijan, which is related to stakhla. The carbon content of steel is between 0. 002% and 2. 1% by weight for plain iron–carbon alloys and these values vary depending on alloying elements such as manganese, chromium, nickel, iron, tungsten, carbon and so on. Basically, steel is an alloy that does not undergo eutectic reaction. In contrast, cast iron does undergo eutectic reaction, too little carbon content leaves iron quite soft, ductile, and weak. Carbon contents higher than those of steel make an alloy, commonly called pig iron, while iron alloyed with carbon is called carbon steel, alloy steel is steel to which other alloying elements have been intentionally added to modify the characteristics of steel. Common alloying elements include, manganese, nickel, chromium, molybdenum, boron, titanium, vanadium, tungsten, cobalt, and niobium. Additional elements are important in steel, phosphorus, sulfur, silicon, and traces of oxygen, nitrogen, and copper. Alloys with a higher than 2. 1% carbon content, depending on other element content, cast iron is not malleable even when hot, but it can be formed by casting as it has a lower melting point than steel and good castability properties
34.
Elasticity (physics)
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In physics, elasticity is the ability of a body to resist a distorting influence or deforming force and to return to its original size and shape when that influence or force is removed. Solid objects will deform when adequate forces are applied on them, if the material is elastic, the object will return to its initial shape and size when these forces are removed. The physical reasons for elastic behavior can be different for different materials. In metals, the atomic lattice changes size and shape when forces are applied, when forces are removed, the lattice goes back to the original lower energy state. For rubbers and other polymers, elasticity is caused by the stretching of polymer chains when forces are applied, perfect elasticity is an approximation of the real world. The most elastic body in modern science found is Quartz fibre which is not even a perfect elastic body, so perfect elastic body is an ideal concept only. Most materials which possess elasticity in practice remain purely elastic only up to very small deformations. In engineering, the amount of elasticity of a material is determined by two types of material parameter, the first type of material parameter is called a modulus, which measures the amount of force per unit area needed to achieve a given amount of deformation. The SI unit of modulus is the pascal, a higher modulus typically indicates that the material is harder to deform. The second type of measures the elastic limit, the maximum stress that can arise in a material before the onset of permanent deformation. Its SI unit is also pascal, when describing the relative elasticities of two materials, both the modulus and the elastic limit have to be considered. Rubbers typically have a low modulus and tend to stretch a lot, of two rubber materials with the same elastic limit, the one with a lower modulus will appear to be more elastic, which is however not correct. When an elastic material is deformed due to a force, it experiences internal resistance to the deformation. The various moduli apply to different kinds of deformation, for instance, Youngs modulus applies to extension/compression of a body, whereas the shear modulus applies to its shear. The elasticity of materials is described by a curve, which shows the relation between stress and strain. The curve is nonlinear, but it can be approximated as linear for sufficiently small deformations. For even higher stresses, materials exhibit behavior, that is, they deform irreversibly. Elasticity is not exhibited only by solids, non-Newtonian fluids, such as viscoelastic fluids, in response to a small, rapidly applied and removed strain, these fluids may deform and then return to their original shape. Under larger strains, or strains applied for longer periods of time, because the elasticity of a material is described in terms of a stress-strain relation, it is essential that the terms stress and strain be defined without ambiguity
35.
Friction
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Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction, Dry friction resists relative lateral motion of two surfaces in contact. Dry friction is subdivided into static friction between non-moving surfaces, and kinetic friction between moving surfaces, fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces, skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body. Internal friction is the force resisting motion between the making up a solid material while it undergoes deformation. When surfaces in contact move relative to other, the friction between the two surfaces converts kinetic energy into thermal energy. This property can have consequences, as illustrated by the use of friction created by rubbing pieces of wood together to start a fire. Kinetic energy is converted to thermal energy whenever motion with friction occurs, another important consequence of many types of friction can be wear, which may lead to performance degradation and/or damage to components. Friction is a component of the science of tribology, Friction is not itself a fundamental force. Dry friction arises from a combination of adhesion, surface roughness, surface deformation. The complexity of interactions makes the calculation of friction from first principles impractical and necessitates the use of empirical methods for analysis. Friction is a non-conservative force - work done against friction is path dependent, in the presence of friction, some energy is always lost in the form of heat. Thus mechanical energy is not conserved, the Greeks, including Aristotle, Vitruvius, and Pliny the Elder, were interested in the cause and mitigation of friction. They were aware of differences between static and kinetic friction with Themistius stating in 350 A. D. that it is easier to further the motion of a moving body than to move a body at rest. The classic laws of sliding friction were discovered by Leonardo da Vinci in 1493, a pioneer in tribology and these laws were rediscovered by Guillaume Amontons in 1699. Amontons presented the nature of friction in terms of surface irregularities, the understanding of friction was further developed by Charles-Augustin de Coulomb. Coulomb further considered the influence of sliding velocity, temperature and humidity, the distinction between static and dynamic friction is made in Coulombs friction law, although this distinction was already drawn by Johann Andreas von Segner in 1758. Leslie was equally skeptical about the role of adhesion proposed by Desaguliers, in Leslies view, friction should be seen as a time-dependent process of flattening, pressing down asperities, which creates new obstacles in what were cavities before
36.
Brake
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A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a vehicle, wheel, axle, or to prevent its motion. Most brakes commonly use friction between two surfaces pressed together to convert the energy of the moving object into heat, though other methods of energy conversion may be employed. For example, regenerative braking converts much of the energy to electrical energy, other methods convert kinetic energy into potential energy in such stored forms as pressurized air or pressurized oil. Eddy current brakes use magnetic fields to convert energy into electric current in the brake disc, fin, or rail. Still other braking methods even transform kinetic energy into different forms, Brakes are generally applied to rotating axles or wheels, but may also take other forms such as the surface of a moving fluid. In practice, fast vehicles usually have significant air drag, almost all wheeled vehicles have a brake of some sort. Even baggage carts and shopping carts may have them for use on a moving ramp, most fixed-wing aircraft are fitted with wheel brakes on the undercarriage. Some aircraft also feature air brakes designed to reduce their speed in flight, notable examples include gliders and some World War II-era aircraft, primarily some fighter aircraft and many dive bombers of the era. These allow the aircraft to maintain a speed in a steep descent. The Saab B17 dive bomber and Vought F4U Corsair fighter used the deployed undercarriage as an air brake, Friction brakes on automobiles store braking heat in the drum brake or disc brake while braking then conduct it to the air gradually. When traveling downhill some vehicles can use their engines to brake, when the brake pedal of a modern vehicle with hydraulic brakes is pushed against the master cylinder, ultimately a piston pushes the brake pad against the brake disc which slows the wheel down. On the brake drum it is similar as the cylinder pushes the brake shoes against the drum which also slows the wheel down, Brakes may be broadly described as using friction, pumping, or electromagnetics. Typically the term brake is used to mean pad/shoe brakes and excludes hydrodynamic brakes. Friction brakes are often rotating devices with a pad and a rotating wear surface. Other brake configurations are used, but less often, a drum brake is a vehicle brake in which the friction is caused by a set of brake shoes that press against the inner surface of a rotating drum. The drum is connected to the rotating roadwheel hub, drum brakes generally can be found on older car and truck models. However, because of their low production cost, drum brake setups are also installed on the rear of some low-cost newer vehicles, compared to modern disc brakes, drum brakes wear out faster due to their tendency to overheat
37.
Leather
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Leather is a durable and flexible material created by tanning animal rawhide and skin, often cattle hide. It can be produced at manufacturing scales ranging from cottage industry to heavy industry, people use leather to make various goods—including clothing, bookbinding, leather wallpaper, and as a furniture covering. It is produced in a variety of types and styles. Several tanning processes transform hides and skins into leather, Chrome-tanned leather, invented in 1858, is tanned using chromium sulfate and it is more supple and pliable than vegetable-tanned leather and does not discolor or lose shape as drastically in water as vegetable-tanned. It is also known as wet-blue for its color derived from the chromium, more exotic colors are possible when using chrome tanning. The chrome tanning method usually only takes a day to finish, and it is reported that chrome-tanned leather adds up to 80% of the global leather supply. Vegetable-tanned leather is tanned using tannins and other found in different vegetable matter, such as tree bark prepared in bark mills, wood, leaves, fruits. It is supple and brown in color, with the exact shade depending on the mix of chemicals and it is the only form of leather suitable for use in leather carving or stamping. Vegetable-tanned leather is not stable in water, it tends to discolor, so if left to soak and then dried it shrinks, in hot water, it shrinks drastically and partly congeals—becoming rigid, and eventually brittle. Boiled leather is an example of this, where the leather has been hardened by being immersed in hot water, historically, it was occasionally used as armour after hardening, and it has also been used for book binding. Aldehyde-tanned leather is tanned using glutaraldehyde or oxazolidine compounds and this is the leather that most tanners refer to as wet-white leather due to its pale cream or white color. It is the type of chrome-free leather, often seen in shoes for infants. Formaldehyde tanning is another aldehyde tanning method, brain-tanned leathers fall into this category, and are exceptionally water absorbent. Brain tanned leathers are made by a process that uses emulsified oils, often those of animal brains such as deer, cattle. They are known for their softness and washability. Chamois leather also falls into the category of aldehyde tanning, and like brain tanning, produces a porous, chamois leather is made using marine oils that oxidize easily to produce the aldehydes that tan the leather to color it. Rose-tanned leather is a variation of oil tanning and brain tanning. Rose-tanned leather tanned leaves a powerful rose fragrance even years from when it is manufactured and it has been called the most valuable leather on earth, but this is mostly due to the high cost of rose otto and its labor-intensive tanning process
38.
Ford Model T
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The Ford Model T is an automobile that was produced by Ford Motor Company from October 1,1908, to May 26,1927. The Ford Model T was named the most influential car of the 20th century in the 1999 Car of the Century competition, ahead of the BMC Mini, Citroën DS, and Volkswagen Type 1. With 16.5 million sold it stands eighth on the top ten list of most sold cars of all time as of 2012, although automobiles had already existed for decades, they were still mostly scarce and expensive at the Model Ts introduction in 1908. Positioned as reliable, easily maintained mass market transportation, it was a runaway success, in a matter of days after the release,15,000 orders were placed. The first production Model T was produced on August 12,1908 and left the factory on September 27,1908, at the Ford Piquette Avenue Plant in Detroit, Michigan. On May 26,1927, Henry Ford watched the 15 millionth Model T Ford roll off the line at his factory in Highland Park. There were several cars produced or prototyped by Henry Ford from the founding of the company in 1903 until the Model T was introduced, although he started with the Model A, there were not 19 production models, some were only prototypes. The production model immediately before the Model T was the Model S, a version of the companys largest success to that point. The follow-up was the Ford Model A, the company publicity said this was because the new car was such a departure from the old that Henry wanted to start all over again with the letter A. The Model T was Fords first automobile mass-produced on moving assembly lines with completely interchangeable parts, Henry Ford said of the vehicle, I will build a car for the great multitude. It will be enough for the family, but small enough for the individual to run. It will be constructed of the best materials, by the best men to be hired, after the simplest designs that modern engineering can devise. But it will be so low in price that no man making a good salary will be unable to own one –, although credit for the development of the assembly line belongs to Ransom E. The Model T was designed by Childe Harold Wills, and Hungarian immigrants Joseph A. Galamb, Henry Love, C. J. Smith, Gus Degner and Peter E. Martin were also part of the team. Production of the Model T began in the quarter of 1908. Collectors today sometimes classify Model Ts by build years and refer to these as model years and this is a retroactive classification scheme, the concept of model years as we conceive it today did not exist at the time. The nominal model designation was Model T, although design revisions did occur during the two decades of production. The Model T had a front-mounted 177-cubic-inch inline four-cylinder engine, producing 20 hp, according to Ford Motor Company, the Model T had fuel economy on the order of 13–21 mpg‑US
39.
Nickel titanium
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Nickel titanium, also known as Nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages e. g. Nitinol 55, Nitinol 60. Nitinol alloys exhibit two closely related and unique properties, shape memory effect and superelasticity, Shape memory is the ability of nitinol to undergo deformation at one temperature, then recover its original, undeformed shape upon heating above its transformation temperature. The word Nitinol is derived from its composition and its place of discovery, william J. Buehler along with Frederick Wang, discovered its properties during research at the Naval Ordnance Laboratory in 1959. Buehler was attempting to make a better missile nose cone, which could resist fatigue, heat, having found that a 1,1 alloy of nickel and titanium could do the job, in 1961 he presented a sample at a laboratory management meeting. The sample, folded up like an accordion, was passed around, one of them applied heat from his pipe lighter to the sample and, to everyones surprise, the accordion-shaped strip stretched and took its previous shape. While the potential applications for nitinol were realized immediately, practical efforts to commercialize the alloy did not take place until a decade later and this delay was largely because of the extraordinary difficulty of melting, processing and machining the alloy. Even these efforts encountered financial challenges that were not readily overcome until the 1980s, the discovery of the shape-memory effect in general dates back to 1932, when Swedish chemist Arne Ölander first observed the property in gold-cadmium alloys. The same effect was observed in Cu-Zn in the early 1950s, at high temperatures, nitinol assumes an interpenetrating simple cubic structure referred to as austenite. At low temperatures, nitinol spontaneously transforms to a more complicated crystal structure known as martensite. There are four transition temperatures associated to the austenite-to-martensite and martensite-to-austenite transformations, when the alloy is fully martensite and is subjected to heating, austenite starts to form at the austenite start temperature, As, and finishes at the austenite finish temperature, Af. The cooling/heating cycle shows thermal hysteresis, the hysteresis width depends on the precise nitinol composition and processing. Its typical value is a range spanning about 20-50 K. Crucial to nitinol properties are two key aspects of this phase transformation, first is that the transformation is reversible, meaning that heating above the transformation temperature will revert the crystal structure to the simpler austenite phase. The second key point is that the transformation in both directions is instantaneous, martensites crystal structure has the unique ability to undergo limited deformation in some ways without breaking atomic bonds. This type of deformation is known as twinning, which consists of the rearrangement of atomic planes without causing slip and it is able to undergo about 6–8% strain in this manner. When martensite is reverted to austenite by heating, the austenitic structure is restored. Thus the name shape memory refers to the fact that the shape of the high temperature austenite phase is remembered, even though the alloy is severely deformed at a lower temperature. A great deal of pressure can be produced by preventing the reversion of deformed martensite to austenite — from 35,000 psi to, in many cases, more than 100,000 psi
40.
Mors (automobile)
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The Mors automobile factory was an early French car manufacturer. It was one of the first to part in automobile racing, beginning in 1897, due to the belief of the company founder, Émile Mors. By the turn of the century, automobile racing had become largely a contest between Mors and Panhard et Levassor, Mors was one of the first automobiles to use the V engine configuration. The Mors 60 horsepower Grand Prix car was powered by a 10 litre V4 side valve engine, with magneto ignition and dry sump lubrication, the car had a steel chassis and a four-speed transmission that drove the rear wheels via chain drive, and rear-wheel brakes. In 1902, Mors added pneumatic shock absorbers to their cars, with this car, Henri Fournier was able to win the highly significant Paris-Berlin race, with the drive chain breaking immediately afterwards. Plans to return to auto racing were cancelled due to World War I, andré Citroën became chairman of Mors in 1908 and restored the companys viability. In 1925, Citroën bought Mors outright and closed it down, the company produced a number of models which were sold widely in Europe and in the USA. In 1905 these ranged from 2.3 litres to the 8.1 litre 40/52 HP, post-1918 only sleeve valve engines were used. The marque was resurrected briefly when a few electric cars were made during World War II by a subsidiary electrical company of Émile Mors. Central Automobile Company was the US importer of Mors automobiles in New York, the 1904 Mors 18 HP was a touring car. Equipped with a tonneau, it could seat 4 to 6 passengers, the vertically mounted water-cooled straight-4, situated at the front of the car, produced 18 HP. The pressed steel-framed car was quite modern, with a cellular radiator, the Mors 11 HP sold for US$5000. The St. Louis Car Company also manufactured the American Mors, after making the American Mors for three years, the company turned to the manufacture of a car of their own design, the Standard Six. Frank Leslies Popular Monthly Georgano, Nick, the Beaulieu Encyclopedia of the Automobile. ISBN 1-57958-293-1 Kimes, Beverley Rae, & Clark Jr, Henry Austin, Standard Catalog of American cars, 1805-1942
41.
Auto racing
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Auto racing is a sport involving the racing of automobiles for competition. Almost as soon as automobiles had been invented, races of various sorts were organised, by the 1930s specialist racing cars had developed. There are now numerous different categories, each with different rules and it was won by the carriage of Isaac Watt Boulton. Internal combustion auto racing events began soon after the construction of the first successful gasoline-fueled automobiles, the first organized contest was on April 28,1887, by the chief editor of Paris publication Le Vélocipède, Monsieur Fossier. It ran 2 kilometres from Neuilly Bridge to the Bois de Boulogne, on July 22,1894, the Parisian magazine Le Petit Journal organized what is considered to be the worlds first motoring competition, from Paris to Rouen. One hundred and two competitors paid a 10-franc entrance fee, the first American automobile race is generally held to be the Thanksgiving Day Chicago Times-Herald race of November 28,1895. Press coverage of the event first aroused significant American interest in the automobile, brooklands, in Surrey, was the first purpose-built motor racing venue, opening in June 1907. It featured a 4.43 km concrete track with high-speed banked corners, One of the oldest existing purpose-built automobile racing circuits in the United States, still in use, is the 2. 5-mile -long Indianapolis Motor Speedway in Speedway, Indiana. It is the largest capacity venue of any variety worldwide, with a top capacity of some 257. NASCAR was founded by Bill France, Sr. on February 21,1948, the first NASCAR Strictly Stock race ever was held on June 19,1949, at Daytona Beach, Florida. From 1962, sports cars temporarily took a seat to GT cars. From 1972 through 2003, NASCARs premier series was called the Winston Cup Series, the changes that resulted from RJRs involvement, as well as the reduction of the schedule from 48 to 31 races a year, established 1972 as the beginning of NASCARs modern era. The IMSA GT Series evolved into the American Le Mans Series, the European races eventually became the closely related Le Mans Series, both of which mix prototypes and GTs. The best-known variety of racing, Formula One, which hosts the famous Monaco Grand Prix. In single-seater, the wheels are not covered, and the cars often have aerofoil wings front, in Europe and Asia, open-wheeled racing is commonly referred to as Formula, with appropriate hierarchical suffixes. In North America, the Formula terminology is not followed, the sport is usually arranged to follow an international format, a regional format, and/or a domestic, or country-specific, format. In North America, the used in the National Championship have traditionally been similar though less sophisticated than F1 cars. The series most famous race is the Indianapolis 500, the other major international single-seater racing series is GP2
42.
Drag racing
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Drag racing is a type of motor racing in which automobiles or motorcycles compete, usually two at a time, to be first to cross a set finish line. Electronic timing and speed sensing systems have used to record race results since the 1960s. This article covers the legal sport, before each race, each driver is allowed to perform a burnout, which heats the driving tires and lays rubber down at the beginning of the track, improving traction. Each driver then lines up at the starting line, current NHRA trees, for example, feature one blue light, then three amber, one green, and one red. When the first light beam is broken by a front tire, the vehicle is pre-staged. When the second beam is broken, the vehicle is staged. Vehicles may then leave the beam, but must remain in the stage beam until the race starts. Once one competitor is staged, their opponent has a set amount of time to stage or they will be disqualified, indicated by a red light on the tree. Otherwise, once both drivers are staged, the system chooses a short delay at random, then starts the race, the light sequence at this point varies slightly. For example, in NHRA Professional classes, three amber lights on the tree flash simultaneously, followed 0.4 seconds later by a green light. In NHRA Sportsman classes, the amber lights illuminate in sequence from top to bottom,0.5 seconds apart, if a vehicle leaves the start line before the green light illuminates, the red light for that lane illuminates instead, and the driver is disqualified. As a red light infraction is only assessed to the driver with the worse infraction, even if both drivers leave early, the green light is automatically lit for the driver that left last, and they still may win the pass. Several measurements are taken for each race, reaction time, elapsed time, reaction time is the period from the green light illuminating to the vehicle leaving the starting line. Elapsed time is the period from the leaving the starting line to crossing the finish line. Speed is measured through a speed trap covering the final 66 feet to the finish line, except where a breakout rule is in place, the winner is the first vehicle to cross the finish line, and therefore the driver with the lowest combined reaction time and elapsed time. Because these times are measured separately, a driver with an elapsed time can actually win if that drivers advantage in reaction time exceeds the elapsed time difference. In heads-up racing, this is known as a holeshot win, in categories where a breakout rule is in effect, if a competitor is faster than his or her predetermined time, that competitor loses. If both competitors are faster than their predetermined times, the competitor who breaks out by less time wins, regardless, a red light foul is worse than a breakout, except in Junior Dragster where exceeding the absolute limit is a cause for disqualification
43.
Nitrogen
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Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772, although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. Nitrogen is the lightest member of group 15 of the periodic table, the name comes from the Greek πνίγειν to choke, directly referencing nitrogens asphyxiating properties. It is an element in the universe, estimated at about seventh in total abundance in the Milky Way. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2, dinitrogen forms about 78% of Earths atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids, in the nucleic acids, the human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, many industrially important compounds, such as ammonia, nitric acid, organic nitrates, and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen, the second strongest bond in any diatomic molecule. Synthetically produced ammonia and nitrates are key industrial fertilisers, and fertiliser nitrates are key pollutants in the eutrophication of water systems. Apart from its use in fertilisers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric, Nitrogen is a constituent of every major pharmacological drug class, including antibiotics. Many notable nitrogen-containing drugs, such as the caffeine and morphine or the synthetic amphetamines. Nitrogen compounds have a long history, ammonium chloride having been known to Herodotus. They were well known by the Middle Ages, alchemists knew nitric acid as aqua fortis, as well as other nitrogen compounds such as ammonium salts and nitrate salts. The mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold, the discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air. Though he did not recognise it as a different chemical substance, he clearly distinguished it from Joseph Blacks fixed air. The fact that there was a component of air that does not support combustion was clear to Rutherford, Nitrogen was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as air or azote, from the Greek word άζωτικός. In an atmosphere of nitrogen, animals died and flames were extinguished
44.
Cavitation
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Cavitation is the formation of vapour cavities in a liquid – i. e. small liquid-free zones – that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to changes of pressure that cause the formation of cavities where the pressure is relatively low. When subjected to pressure, the voids implode and can generate an intense shock wave. Cavitation is a significant cause of wear in some engineering contexts, collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal causing a type of wear also called cavitation, the most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior, inertial cavitation and non-inertial cavitation, inertial cavitation is the process where a void or bubble in a liquid rapidly collapses, producing a shock wave. Inertial cavitation occurs in nature in the strikes of mantis shrimps and pistol shrimps, in man-made objects, it can occur in control valves, pumps, propellers and impellers. Non-inertial cavitation is the process in which a bubble in a fluid is forced to oscillate in size or shape due to form of energy input. Such cavitation is often employed in ultrasonic cleaning baths and can also be observed in pumps, propellers, since the shock waves formed by collapse of the voids are strong enough to cause significant damage to moving parts, cavitation is usually an undesirable phenomenon. It is very often specifically avoided in the design of such as turbines or propellers. However, it is useful and does not cause damage when the bubbles collapse away from machinery. Inertial cavitation was first studied by Lord Rayleigh in the late 19th century, when a volume of liquid is subjected to a sufficiently low pressure, it may rupture and form a cavity. This phenomenon is coined cavitation inception and may occur behind the blade of a rotating propeller or on any surface vibrating in the liquid with sufficient amplitude. A fast-flowing river can cause cavitation on rock surfaces, particularly there is a drop-off. Other ways of generating cavitation voids involve the local deposition of energy, vapor gases evaporate into the cavity from the surrounding medium, thus, the cavity is not a perfect vacuum, but has a relatively low gas pressure. Such a low-pressure bubble in a liquid begins to collapse due to the pressure of the surrounding medium. As the bubble collapses, the pressure and temperature of the vapor within increases, at the point of total collapse, the temperature of the vapor within the bubble may be several thousand kelvin, and the pressure several hundred atmospheres. Inertial cavitation can occur in the presence of an acoustic field
