Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Electric local

There are other options for generating small amounts of electricity locally, including micro-turbines fueled by natural gas, diesel engines, and PVs. Micro-turbines can also help... [Pg.24]

Aside from contact electrization, local accumulation of charges takes place as a result of mechanical separation and formation of a double electrical layer (DEL). Mechanical separation of charges is brought about by exfoliation of adhesive films from the metal or semiconducting samples. DEL may arise in response to chemical interactions of two phases or as a result of selective adsorption of similar ions, e.g. in the presence of oriented dipoles on the contact surface of one of the phases. Electrization can also be induced by the donor-acceptor (DA) interaction, since in agreement with the electrostatic theory of adhesion DEL are formed at the interface of two substances at the expense of DA links and govern the efficiency of adhesive interactions [41]. [Pg.272]

Pitting corrosion is often observed by the naked eye, as small holes or impressions on metals. There are still discussions about the precise mechanisms for pitting corrosion. One mechanism of interest to the authors is that a special absorption of chloride ion onto a local area of a material s surface brings about pitting corrosion. As shown in Fig. 6, the absorption of chloride ion breaks the balance of electricity locally. To compensate for it, the hydrogen concentration increases in the area. This leads to the decrease of pH and the local part corrodes as a result. However, it is hard to demonstrate it scientifically. This is still a hypothesis, even though the pitting corrosion clearly depends on the concentration of chloride ion. [Pg.27]

Under the assumption that the instantaneous total molecular dipole moment M can be expressed in terms of effective electrical localized atomic charges q, ... [Pg.767]

Beam pumping and electric submersible pumps (ESP) require a source of power. On land it may be convenient to tap into the local electricity network, or in the case of the beam pump to use a diesel powered engine. Offshore (ESP only) provision for power generation must be made to drive down hole electric pumps. [Pg.259]

In some undersaturated reservoirs with non commercial quantities of gas but too much to flare, gas has be used to fuel gas turbines and generate electricity for local use. [Pg.362]

The application of load in materials produces internal modifications such as crack growth, local plastic deformation, corrosion and phase changes, which are accompanied by the emission of acoustic waves in materials. These waves therefore contain information on the internal behaviour of the material and can be analysed to obtain this information. The waves are detected by the use of suitable sensors, that converts the surface movements of the material into electric signal. These signals are processed, analysed and recorded by an appropriate instrumentation. [Pg.31]

At steady electrical load the background noise is normally low and fairly constant along the SH headers and with time no AE sources come up on the Unit 3 header, while the very few localized events recorded on Unit 4 are spread out over the whole length of the header. [Pg.79]

In contrast to a direct injection of dc or ac currents in the sample to be tested, the induction of eddy currents by an external excitation coil generates a locally limited current distribution. Since no electrical connection to the sample is required, eddy current NDE is easier to use from a practical point of view, however, the choice of the optimum measurement parameters, like e.g. the excitation frequency, is more critical. Furthermore, the calculation of the current flow in the sample from the measured field distribution tends to be more difficult than in case of a direct current injection. A homogenous field distribution produced by e.g. direct current injection or a sheet inducer [1] allows one to estimate more easily the defect geometry. However, for the detection of technically relevant cracks, these methods do not seem to be easily applicable and sensitive enough, especially in the case of deep lying and small cracks. [Pg.255]

Electromagnetic earthquake forerunners show themselves like the electromagnetic phenomena, including electromagnetic emission (EME) in a radio frequency range. This emission caused by collective exiting of the set of local mechano-electrical transformers (MET). The excitation mechanism inside the crust is determined by the fact that elastic tension ranges up to the threshold level within the source area. [Pg.914]

IHP) (the Helmholtz condenser formula is used in connection with it), located at the surface of the layer of Stem adsorbed ions, and an outer Helmholtz plane (OHP), located on the plane of centers of the next layer of ions marking the beginning of the diffuse layer. These planes, marked IHP and OHP in Fig. V-3 are merely planes of average electrical property the actual local potentials, if they could be measured, must vary wildly between locations where there is an adsorbed ion and places where only water resides on the surface. For liquid surfaces, discussed in Section V-7C, the interface will not be smooth due to thermal waves (Section IV-3). Sweeney and co-workers applied gradient theory (see Chapter III) to model the electric double layer and interfacial tension of a hydrocarbon-aqueous electrolyte interface [27]. [Pg.179]

The higher-order bulk contribution to the nonlmear response arises, as just mentioned, from a spatially nonlocal response in which the induced nonlinear polarization does not depend solely on the value of the fiindamental electric field at the same point. To leading order, we may represent these non-local tenns as bemg proportional to a nonlinear response incorporating a first spatial derivative of the fiindamental electric field. Such tenns conespond in the microscopic theory to the inclusion of electric-quadnipole and magnetic-dipole contributions. The fonn of these bulk contributions may be derived on the basis of synnnetry considerations. As an example of a frequently encountered situation, we indicate here the non-local polarization for SFIG in a cubic material excited by a plane wave (co) ... [Pg.1279]

The PCM algorithm is as follows. First, the cavity siuface is determined from the van der Waals radii of the atoms. That fraction of each atom s van der Waals sphere which contributes to the cavity is then divided into a nmnber of small surface elements of calculable surface area. The simplest way to to this is to define a local polar coordinate frame at tlie centre of each atom s van der Waals sphere and to use fixed increments of AO and A(p to give rectangular surface elements (Figure 11.22). The surface can also be divided using tessellation methods [Paschual-Ahuir d al. 1987]. An initial value of the point charge for each surface element is then calculated from the electric field gradient due to the solute alone ... [Pg.612]

Solidification. The heat of the electric arc melts a portion of the base metal and any added filler metal. The force of the arc produces localized flows within the weld pools, thus providing a stirring effect, which mixes the filler metal and that portion of the melted base metal into a fairly homogeneous weld metal. There is a very rapid transfer of heat away from the weld to the adjacent, low temperature base metal, and solidification begins nearly instantaneously as the welding heat source moves past a given location. [Pg.345]

The choice of technology, the associated capital, and operating costs for a chlor—alkaU plant are strongly dependent on local factors. Especially important are local energy and transportation costs, as are environmental constraints. The primary difference ia operating costs between diaphragm, mercury, and membrane cell plants results from variations ia electricity requirements for the three processes (Table 25) so that local energy and steam costs are most important. [Pg.519]

Electroporation. When bacteria are exposed to an electric field a number of physical and biochemical changes occur. The bacterial membrane becomes polarized at low electric field. When the membrane potential reaches a critical value of 200—300 mV, areas of reversible local disorganization and transient breakdown occur resulting in a permeable membrane. This results in both molecular influx and efflux. The nature of the membrane disturbance is not clearly understood but bacteria, yeast, and fungi are capable of DNA uptake (see Yeasts). This method, called electroporation, has been used to transform a variety of bacterial and yeast strains that are recalcitrant to other methods (2). Apparatus for electroporation is commercially available, and constant improvements in the design are being made. [Pg.247]

The interface between conductor shield and insulation is the region of the highest stress in the cable insulation stmcture. Any imperfections at this interface, especially sharp protmsions of the conductor shield into the insulation, will cause high local electrical stress that may reduce the dielectric strength of finished cable. Calculation of the stress enhancement, for a 15 kV cable with a 4.4 mm (175 mil) insulation thickness, indicates that the common round 50 p.m (2 mil) radius protmsions increase the electrical stress by a factor of 30 and a sharp 5 fim protmsion will increase the electric stress by as much as 210 times (11,20). [Pg.329]

The demand for DRI varies depending on local market conditions. In industrialized countries, DRI primarily is used as a supplement to scrap for controlling residual elements in electric arc furnace steelmaking. In regions where scrap is scarce, DRI is used as a replacement in production of all grades of steel. In 1993, Latin America produced 9.4 X 10 t (39.3%) of the world s DRI. Middle East/North Africa produced 6.1 X 10 t (25.6%), Asia/Oceania produced 4.4 X 10 t (18.4%), and CIS/Eastem Europe produced 1.7 x 10 t (7.1%). North America produced 1.2 x 10 t (5.0%) Africa, 0.9 x 10 t (3.8%) and Western Europe, 0.2 x 10 t (0.8%) (1). Nearly 79% of the DRI produced is consumed in steel mills adjacent to the DR plants called captive plants. Plants which are designed to sell and ship DRI on the open market are called merchant plants. [Pg.431]

Coals of the western part of Germany usuady occur ia thinner seams and ia more local areas. The maia produciag areas are west of Cologae with opea-cast mines at Vide, Frechea, Garsdorf, and Frimmersdorf. This brown coal is important to electric power generation (27). [Pg.154]


See other pages where Electric local is mentioned: [Pg.116]    [Pg.126]    [Pg.226]    [Pg.380]    [Pg.116]    [Pg.126]    [Pg.226]    [Pg.380]    [Pg.79]    [Pg.365]    [Pg.1064]    [Pg.169]    [Pg.170]    [Pg.738]    [Pg.1279]    [Pg.1446]    [Pg.1586]    [Pg.2482]    [Pg.2494]    [Pg.2501]    [Pg.2553]    [Pg.2753]    [Pg.2861]    [Pg.2884]    [Pg.255]    [Pg.292]    [Pg.399]    [Pg.401]    [Pg.127]    [Pg.5]    [Pg.272]    [Pg.160]    [Pg.160]    [Pg.204]    [Pg.329]    [Pg.123]   
See also in sourсe #XX -- [ Pg.331 , Pg.332 ]

See also in sourсe #XX -- [ Pg.71 ]

See also in sourсe #XX -- [ Pg.85 ]




SEARCH



Electric Field Local

Electric moments localized

Electrical local

Electrical local

Local analyses electrical conductivity

Local electric charge density

Local electric charge density potential

Local electric polarization

Local electrical potential

Local electrical properties

Localization, electrical double layer

Localized electric fields

Localized electrical effect parameter

Localized electrical effect parameter formation

Localized electrical effects

Localized electrical effects separation

Localized molecular orbitals electric moments

Orbitals localized, electric moments

Small local electric field

The Local Electric Field

© 2024 chempedia.info