Electric transportation systems

With increasing demands for electric transportation systems and/or electric vehicles, semiconductor power modules such as electric power converters and DC-AC inverters will continue to expand in terms of their applications. In these systems, in order to transmit a high electric current, thick copper electrodes are often directly bonded to ceramic substrates, the structures of which may cause major residual stresses in ceramic parts. Thus, to avoid failure due to residual stress, ceramic materials are required to have a high strength and, in order to further improve the reUabUity of the systems, improvements in the mechanical properties of high-thermal conductivity materials are clearly required. Consequently, the electrical industries are continuing an active search for alternative materials with both high thermal conductivity and superior mechanical properties. 

In electric power systems, it is essential to have permanent control of the power in electricity production, transportation, and consumption. Because of speed and reliability requirements, electric power systems were the first large systems to use a variety of automatic control devices for the protection of different parts of the system. 

An electric power system involves the production and transportation of electrical energy from generating facilities to energy-consuming customers. This is accomplished through a complex network of transmission lines, switching and transformer stations. 

The North American electric power transmission system has been described as the largest, most complex machine ever built by humanity. It is a massive network of generating stations, transmission lines, substations, distribution lines, motors, and other electrical loads all interdependently linked for the conversion, transportation, and control of electrical energy. Approximately 60 percent of all energy utilized in the United States passes through the interconnected electric power system. The major goal of the system is to most efficiently and reliably deliver electric power from generating stations to residential, commercial, and industrial consumers. 

See also Batteries Capacitors and Ultracapacitors Electric Motor Systems Emission Control, Vehicle Environmental Problems and Energy Use Flywheels Fuel Cells Fuel Cell Vehicles Flybrid Vehicles Materials Transportation, Evolution ofEnergy Use and. 

Aimstrong, J. H. (1993). The Railroad What It Is, What It Does, 3rd ed. Omaha Simmons-Boardman Books, Inc. Bilz, F., and Hnlger, S. (1998). A Decade of Three-phase Traction Technoogy for Diesel-Electric Locomotives in North America. Translated from ZEV+DET Glassers Aimalen 121(9)71997. Siemens AG Transportation Systems Group. 

As crude oil reserves dwindle, the marketplace will either transition to the electrifying of the transportation system (electric and fuel-cell vehicles and electric railways), with the electricity being produced by coal, natural gas, nuclear and renewables, or see the development of an industry to produce liquid fuel substitutes from coal, oil shale, and tar sands. It might also turn out to be a combination of both. The transition will vary by nation and will be dictated strongly by the fuels available, the economic and technological efficiencies of competitive systems, the relative environmental impacts of each technology, and the role government takes in the marketplace. 

Pratt, T. H., Static Electricity in Pneumadc Transport Systems, Process Safety Progress, V. 13, No. 3, 1994, p. 109. 

Synaptic vesicles isolated from brain exhibit four distinct vesicular neurotransmitter transport activities one for monoamines, a second for acetylcholine, a third for the inhibitory neurotransmitters GABA and glycine, and a fourth for glutamate [1], Unlike Na+-dependent plasma membrane transporters, the vesicular activities couple to a proton electrochemical gradient (A. lh+) across the vesicle membrane generated by the vacuolar H+-ATPase ( vacuolar type proton translocating ATPase). Although all of the vesicular transport systems rely on ApH+, the relative dependence on the chemical and electrical components varies (Fig. 1). The... 

Metals and semiconductors are electronic conductors in which an electric current is carried by delocalized electrons. A metallic conductor is an electronic conductor in which the electrical conductivity decreases as the temperature is raised. A semiconductor is an electronic conductor in which the electrical conductivity increases as the temperature is raised. In most cases, a metallic conductor has a much higher electrical conductivity than a semiconductor, but it is the temperature dependence of the conductivity that distinguishes the two types of conductors. An insulator does not conduct electricity. A superconductor is a solid that has zero resistance to an electric current. Some metals become superconductors at very low temperatures, at about 20 K or less, and some compounds also show superconductivity (see Box 5.2). High-temperature superconductors have enormous technological potential because they offer the prospect of more efficient power transmission and the generation of high magnetic fields for use in transport systems (Fig. 3.42). 

To study the electrical transport properties of this double-barrier system Pd nanoclusters have been trapped in this gap. Figure 14 shows a typical l(U) curve. The most pronounced feature at 4.2 K is the Coulomb gap at a voltage of about 55 mV, which disappears at 295 K. Above the gap voltage, the l(U) curve is not linear, but increases exponentially, which was explained by a suppression of the effective tunnel barrier by the applied voltage. 

Ventra MD (2008) Electrical transport in nanoscale systems. Cambridge University Press, Cambridge... 

Transport systems may also produce membrane potentials 97 Electrical signals recorded from cells are of two types stereotyped action potentials and a variety of slow potentials 97... 

These transport systems use a primary source of energy to drive active transport of a solute against a concentration gradient. Primary energy sources can be chemical, electrical and solar. In this section, systems will be described mainly that hydrolyse the diphosphate bond of inorganic pyrophosphate, ATP, or another nucleoside triphosphate, in order to drive the active uptake of solutes. Transporters using another primary source of energy will be briefly mentioned. 

In 1900, there were only a few thousand motor vehicles in the United States and the public had a choice between steam, electric, or gasoline automobiles. A gasoline-based transportation system was not a foregone conclusion. The public had become used to horses and the image of sitting near a boiler, battery or gas tank and moving by a series of explosions, was not attractive. 

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