Internal current

The Batch Reaction Subcommittee was chaired by Walter L. Lrank of EQE International. Current members of the subcommittee, listed alphabetically are David J. Christensen, Union Carbide Corporation Warren Greenfield, International Specialty Products Philip P. Malkewicz, Nalco Chemical Company Peter L. McGrath, Olin Corporation Louisa A. Nara, Bayer Corporation Leslie A. Seller, CCPS Staff Consultant Robert Schisla, Eastman Chemical Company Anthony Torres, Eastman Kodak Company Dr. Jan C. Windhorst, Nova Chemicals and Paul Wood, Eli Lilly Company. Eormer subcommittee members who contributed much in getting this project started were Eelix Ereiheiter, CCPS Staff Consultant (deceased) A1 Noren, Monsanto Company-Searle (deceased) John Noronha, Eastman Kodak Company (retired) and Robert Stankovich, Eli Lilly Company. 

Figure 12.20 shows the structure of the side-window circular cage type and linear focused head-on type of photomultiplier which are both preeminent in fluorescence studies. The lower cost of side-window tubes tends to favor their use for steady-state studies, whereas the ultimate performance for lifetime studies is probably at present provided by linear focused devices. In both types internal current amplification is achieved by virtue of secondary electron emission from discrete dynode stages, usually constructed of copper-beryllium (CuBe) alloy, though gallium-phosphide (GaP) first dynodes have been used to obtain higher gains. 

By fixing the chimney to a circular collar, which screws up or down upon the triangular support, Mr. Lows is enabled, in his improvement upon this form of burner, to alter tho direction of the externa] current caused by the contraction of the chimney and by converting the button into a screw, its hoight can also be altered, and the Internal current regulated. 

The superfbid properties of this model are unusual because of the unusual form of the current operator. Fundamental to this model is the internal current operator, which describes the particle fbw between a- and b-states. For the 7th supercell, the internal current operator can be obtained as follows ... 

Although classical mechanics does not provide a diamagnetic contribution to the susceptibility from collective electrons (induced internal currents and surface currents cancel one another out), Landau (383) discovered that the running waves of quantum mechanics are modified by H to give a diamagnetic susceptibility —1/3 that of the paramagnetic susceptibility. Thus... 

Figure 35 (a) Detection of a beating between the ac current provided by an external source and the internal current oscillation in the sliding SDW state (b) linear dependence of the SDW current against the frequency of the internal current oscillation, harmonics, and subharmonics. (After Ref. 110.)... 

The corrosion current density, like the exchange current density, is an internal current, which is not observed in the external circuit. The potential difference AE is the difference between the applied potential and the open-circuit potential, just as t] is the difference between the applied potential and the reversible potential. The big difference is that i is equal to the anodic and cathodic currents of two entirely... 

Remember that this is an internal current, since the the decay transient is followed at open circuit. It is interesting to note, in this... 

High r factors are, however, not without some other complications since they imply porosity of materials. Porosity can lead to the following difficulties (a) impediment to disengagement of evolved gases or of diffusion of elec-trochemically consumable gases (as in fuel-cell electrodes 7i2) (b) expulsion of electrolyte from pores on gas evolution and (c) internal current distribution effects associated with pore resistance or interparticle resistance effects that can lead to anomalously high Tafel slopes (132, 477) and (d) difficulties in the use of impedance measurements for characterizing adsorption and the double-layer capacitance behavior of such materials. On the other hand, it is possible that finely porous materials, such as Raney nickels, can develop special catalytic properties associated with small atomic metal cluster structures, as known from the unusual catalytic activities of such synthetically produced polyatomic metal clusters (133). 

The total current I in the CLPC method is the sum of the internal current Ii , which flows through the ore body, and the external current 1, which flows through the host rocks. The corresponding total current for the CPC method is only the internal current Ij . Therefore there is a link between limiting currents of the CLPC method and the CPC method (Putikov, 1993),... 

An internal irradiation process leads to the appearance of self-sustained currents observable external current corresponds to internal radioactivity, as far as a surface Coulomb barrier for secondary electrons exists. Such a barrier can be destroyed by heating due to electric conductivity enlarging, which results in the involvement of secondary electrons in electric transport. The thermal-stimulated current, connected with traps liberation can be also observed at a fast heating. Spontaneous electric fields, connected with internal currents, can also be observed. Their strength achieves 1 kV/cm and more at a room temperature. 

Currents within the cells are in the range of a few hundred kiloamperes and magnetic fields are generated within the cell by these internal currents and by the currents flowing in adjacent cells and busbars. All three magnetic field components are significant and vary significantly with position. They have a major... 

Even if the polymeric membrane in a PEM fuel cell is designed to permit only the passage of hydrated hydrogen ion, some electric conductivity and gas permeation cannot be avoided. Then at open-circuit, when no current can be observed through the external circuit, two phenomena can occur at the anode side of a PEM fuel cells, called fuel crossover and internal current. They can be described as follows ... 

The sharp slope change of the polarization curve in Fig. 3.5 suggests that after the first steep voltage diminution up to 2 A, attributed to activation and internal current polarization, another type of losses become predominant. 

Schweitzer, Philip A., ed. 1996. Corrosion Engineering Handbook. New York Marcel Dekker. Caplan, F. 1975. Is Your Water Scaling or Corrosive Chemical Engineering September 1 29. NACE International. Current edition. Methods and Controls to Prevent In-Service Environmental Cracking of Carbon Steel Weldments in Corrosive Petroleum Refinery Environments. NACE RP0472. Houston, TX NACE International. 

NACE International. Current edition. Protection of Austenitic Stainless Steels and Other Austenitic Alloys from Polythionic Stress Corrosion Cracking During Shutdown of Refinery Equipment. NACE RP0170. Houston, TX NACE International. 

Wox = x.M - ecLM = lcon x.M TllC current flows to the Surface counter to the electrons and enters the solution as positive ions (cations), Mm+. Since metal is lost to the solution, corrosion occurs over areas where internal current flows to the metal surface or, conversely, where current is flowing from the surface in the aqueous environment, a useful general rule in the analysis of corroding systems. 

If dA( if/dt is negligible with respect to dA(f>g( /dt, the relationship between internal current flow through the depletion layer, and the measured voltage over R can be obtained directly from Eq. 27 and 29. If dA jjjdt is not negligible, a somewhat more elaborate treatment is necessary. Eq. 28 allows dA /dt to be expressed as a function of dA g ldt, and using Eq. 27 and 29, it is found that... 

The furnace temperature Is measured by means of an internal current-volt-age of the furnace and an external IR detector working above and below a user-... 

Question by R. L. Mela, Dynatech Corporation As the spot moves across the plate, internal currents will be generated within the plate. At high speeds, will not these currents become high compared to the useful generated current ... 

Geselowitz, D.B. 1970. On the magnetic field generated outside an inhomogeneous volume conductor by internal current sources. IEEE Trans. Magn. MAG-6 346. 

Additionally, there is the inherent amplifier noise. It consists of two frequency-dependent components, the internal voltage noise source e and the voltage drop across the source resistance R, caused by an internal current noise generator i . The total input noise for the amplifier with a bandwidth of B=f2 -fi is calculated as the sum of its three independent components ... 

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