Diagrams external

Figure C2.16.7. A schematic energy band diagram of a p-n junction witliout external bias (a) and under forward bias (b). Electrons and holes are indicated witli - and + signs, respectively. It should be remembered tliat tlie energy of electrons increases by moving up, holes by moving down. Electrons injected into tlie p side of tlie junction become minority carriers. Approximate positions of donor and acceptor levels and tlie Feniii level, are indicated.

Extended-zone and reduced-zone representations of band diagram for ID lattice with no external potential. 

Energy level diagram for a molecule showing pathways for deactivation of an excited state vr Is vibrational relaxation Ic Is Internal conversion ec Is external conversion, and Isc Is Intersystem crossing. The lowest vibrational energy level for each electronic state Is Indicated by the thicker line. 

A schematic diagram of a six-vessel UOP Cyclesorb process is shown in Figure 15. The UOP Cyclesorb process has four external streams feed and desorbent enter the process, and extract and raffinate leave the process. In addition, the process has four internal recycles dilute raffinate, impure raffinate, impure extract, and dilute extract. Feed and desorbent are fed to the top of each column, and the extract and raffinate are withdrawn from the bottom of each column in a predeterrnined sequence estabUshed by a switching device, the UOP rotary valve. The flow of the internal recycle streams is from the bottom of a column to the top of the same column in the case of dilute extract and impure raffinate and to the top of the next column in the case of dilute raffinate and impure extract. 

The sohd line in Figure 3 represents the potential vs the measured (or the appHed) current density. Measured or appHed current is the current actually measured in an external circuit ie, the amount of external current that must be appHed to the electrode in order to move the potential to each desired point. The corrosion potential and corrosion current density can also be deterrnined from the potential vs measured current behavior, which is referred to as polarization curve rather than an Evans diagram, by extrapolation of either or both the anodic or cathodic portion of the curve. This latter procedure does not require specific knowledge of the equiHbrium potentials, exchange current densities, and Tafel slope values of the specific reactions involved. Thus Evans diagrams, constmcted from information contained in the Hterature, and polarization curves, generated by experimentation, can be used to predict and analyze uniform and other forms of corrosion. Further treatment of these subjects can be found elsewhere (1—3,6,18). 

FIG. 27-48 Simplified flow diagram for circulating AFBC (with external heat exchanger). 

FIG. 28-15 Sch( niatic diagram of the (icctrochcmical cell used for crevice corrosion testing. Not shown are three hold-down screw s, gas inlet tiil)e, and external thermocouple tiil)e. 

The potential dependence of the velocity of an electrochemical phase boundary reaction is represented by a current-potential curve I(U). It is convenient to relate such curves to the geometric electrode surface area S, i.e., to present them as current-density-potential curves J(U). The determination of such curves is represented schematically in Fig. 2-3. A current is conducted to the counterelectrode Ej in the electrolyte by means of an external circuit (voltage source Uq, ammeter, resistances R and R") and via the electrode E, to be measured, back to the external circuit. In the diagram, the current indicated (0) is positive. The potential of E, is measured with a high-resistance voltmeter as the voltage difference of electrodes El and E2. To accomplish this, the reference electrode, E2, must be equipped with a Haber-Luggin capillary whose probe end must be brought as close as possible to... 

Of all vibration frequeneies, the most dangerous are the synehronous vibrations, where an externally foreed vibration exeites one of the natural (resonant) frequeneies in the maehine. Campbell diagrams eonstrueted by the manufaeturers will help the operator avoid these frequeneies during run-up or eoimuissioning of tlie maehine in question. 

Figure 12.11 Schematic diagram of the ion pore of the K+ channel. From the cytosolic side the pore begins as a water-filled channel that opens up into a water-filled cavity near the middle of the membrane. A narrow passage, the selectivity filter, links this cavity to the external solution. Three potassium ions (purple spheres) bind in the pore. The pore helices (red) are oriented such that their carboxyl end (with a negative dipole moment) is oriented towards the center of the cavity to provide a compensating dipole charge to the K ions. (Adapted from D.A. Doyle et al.. Science 280 69-77, 1998.)...

When analysing meehanieal systems, it is usual to identify all external forees by the use of a Free-body diagram , and then apply Newton s seeond law of motion in the form ... 

The external loop valve is the more commonly used sampling system and offers a wider choice of readily adjustable sample sizes. A modified form of the external loop sample valve has become very popular for quantitative LC analysis, a diagram of which is shown in Figure 3. 

Optimizing the use of flie external MSA The pinch diagram (Fig. 3.12) demonstrates that below the pinch, the load of the waste stream has to be removed by the external MSA, S3. This renders the remainder of this example identical to Example 2.2. ThereftKc, the optimal flowrate of S3 is 0.0234 kg mol/s and the optimal outlet composition of S3 is 0.(X)85. Furthermore, the minimum total annualized cost of the benzene recovery system is 41,560/yr (see Fig. 2.13). 

So far, an MOC solution has been identified through a two-stage process. First, the use of process MSAs is maximized by constructing the pinch diagram with the lean composite stream composed of process MSAs only. In the second stage, the external MSAs are screened to remove the remaining load at minimum cost. 

Suppose that the process does not have any process MSAs. How can a lean composite line be developed The following shortcut method can be employed to construct the pinch diagram for external MSAs. A more rigorous method is presented in Chapter Six. 

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