Active width

To obtain satisfactory compaction across the entire active width of the roller it is necessary to optimize the relationship roll width to feeder width, l/l. Two opposite effects take place which affect the feeder width ... 

By filling in the following equations for the width of cut apd and the active width bd of the dressing roller and considering that aed is much smaller than tp then ... 

Assuming that the width of cut equals the active width of the dressing tool, the overlapping rate is... 

Active width of one detector row in the longitudinal direction, measured at the isocenter. The collimated section thickness can be different from the effective... 

The Ray test RITA is another position-sensitive, proportional-counting thin layer scanner (Figure 13.2). The active width scanned can be limited from 20 mm down to 15, 10.3, and 1 mm by exchange of the diaphragm. Bioscan also manufactures imaging scanners (Rock et al., 1998 Shulman, 1982 and 1983), including the completely redesigned AR-2000. 

Further evidence pointing in the same direction was provided by Pierce, Wiley and Smith, who found that on steam activation of a particular char at 900°C the saturation uptake increased three-fold, yet the isotherm was still of Type I. They argued that even if the width of the pores was only two molecular diameters before activation, it would increase, by removal of oxides, during the activation so that the second Type I isotherm would correspond to pores more than two molecular diameters wide. (The alternative explanation, that activation produced new pores of the same width as the old, seems unlikely.)... 

Calculations of the interaction energy in very fine pores are based on one or other of the standard expressions for the pair-wise interaction between atoms, already dealt with in Chapter 1. Anderson and Horlock, for example, used the Kirkwood-Miiller formulation in their calculations for argon adsorbed in slit-shaped pores of active magnesium oxide. They found that maximum enhancement of potential occurred in a pore of width 4-4 A, where its numerical value was 3-2kcalmol , as compared with 1-12, 1-0 and 1-07 kcal mol for positions over a cation, an anion and the centre of a lattice ceil, respectively, on a freely exposed (100) surface of magnesium oxide. 

In practice the laser can operate only when n, in Equation (9.2), takes values such that the corresponding resonant frequency v lies within the line width of the transition between the two energy levels involved. If the active medium is a gas this line width may be the Doppler line width (see Section 2.3.2). Figure 9.3 shows a case where there are twelve axial modes within the Doppler profile. The number of modes in the actual laser beam depends on how much radiation is allowed to leak out of the cavity. In the example in Figure 9.3 the output level has been adjusted so that the so-called threshold condition allows six axial modes in the beam. The gain, or the degree of amplification, achieved in the laser is a measure of the intensity. 

The frequency response or switching speed of the bipolar transistor is governed by the same processes which control the speed of thep—n junction, the capacitance associated with the movement of charge into and out of the depletion regions. To achieve high frequencies the dimensions of the active areas and parasitic circuit elements must be reduced. The two critical dimensions are the width of the emitter contact and the base thickness, W. The cutoff frequency,, is the frequency at which = 57 / - b /t > where is the emitter-to-coUector delay time and is the sum of the emitter... 

Doppler broadening arises from the random thermal agitation of the active systems, each of which, in its own test frame, sees the appHed light field at a different frequency. When averaged over a Maxwellian velocity distribution, ie, assuming noninteracting species in thermal equilibrium, this yields a line width (fwhm) in cm C... 

The stmcture of activated carbon is best described as a twisted network of defective carbon layer planes, cross-linked by aHphatic bridging groups (6). X-ray diffraction patterns of activated carbon reveal that it is nongraphitic, remaining amorphous because the randomly cross-linked network inhibits reordering of the stmcture even when heated to 3000°C (7). This property of activated carbon contributes to its most unique feature, namely, the highly developed and accessible internal pore stmcture. The surface area, dimensions, and distribution of the pores depend on the precursor and on the conditions of carbonization and activation. Pore sizes are classified (8) by the International Union of Pure and AppHed Chemistry (lUPAC) as micropores (pore width <2 nm), mesopores (pore width 2—50 nm), and macropores (pore width >50 nm) (see Adsorption). 

Approximately 20%, since S < 2b. It is recommended to have the centre spacing S at least 2 x 152.4, i.e. 305 mm. If the width of the enclosure poses a limitation, a more appropriate configuration such as in Figure 28.34 or the technigue of interleaving as in Figure 28.35 may be adopted to achieve better utilization of the active metal. In our calculations we have considered all these alternatives. 

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