Flux ratio factor

The bioaffinity parameter a basically reflects the free metal ion concentration, whereas the limiting flux ratio b reflects the total labile metal species concentration. Due to the complexation, the ratio a/b thus changes by a factor (1 +sKcl) in spherical geometry, while the factor (1 I sKc ) (l I Kc ) is required for planar geometry [26]. 

Role of Bombardment in Pattern Transfer Regime. Gokan et al. [18] measured the relative 02 RIE rates of a series of polymers and found that the RIE rates scaled inversely with the mass density of carbon as in their IBE study (several materials deviated from the correlation). The relative RIE rates [18] varied by a factor of 3 and do not show the large variations characteristic of the radical-induced mechanism [10]. These results strongly suggest a bombardment-induced mechanism, but one can not directly apply the IBE results to RIE conditions because IBE neutral-to-ion flux ratios are orders of magnitude lower than under RIE conditions. 

Alumina and other ceramic membranes of various microfiluaiion pore sizes have been used for the separation of yeast (saccharomyces cerevisiae) from the broth and the clarification of thin stillage [Cheryan, 1994]. A typical flux of 110 L/hr-m can be obtained with a crossflow velocity of 4 m/s and a transmembrane pressure of 1.7 bars. The crossflow velocity is found to markedly affect the membrane flux. Concenuation factors (ratios of final to initial concentrations) of 6 to 10 for both the broth and the stillage can be achieved. Backflushing with a frequency of every 5 minutes and a duration of 5 seconds helps maintain the flux, particularly in the initial operating period. The permeate flux for both types of separation reaches steady state after 30 to 90 minutes. 

When the flux ratios are fixed, we may evaluate the mass transfer rate factor 0 from Eq. 8.2.20... 

The use of chiral membrane solvent to achieve transport stereoselectivity is not very widespread. Probably, the only report describing chiral hquid-phase-enhanced stereoselective transport is amino acid enantiomers separation by means of chiral alcohols, nopol and (2S)-(—)-methylbutan-l-ol [38] (see Fig. 3.9). It was shown that optical separation of six pairs of enantiomers of amino acids is possible in this way. However, the chiral discrimination (expressed as a flux ratio for both enantiomers and denoted as a) was moderate and the best result was 1for serine. As a main conclusion, it was stated that the factor involved in chiral discrimination was an asymmetry of the amino acid molecule. 

Fig. 13.3B Pareto-optimal enzyme manipulation factors in simultaneous maximization of DAHPS and PEPCxylase flux ratios (Case A) (a) 1-enzyme ( ) and 2-enzyme (A) manipulation factor and (b) 3-enzyme manipulation factor (o).

In computing the separation factor, one must use appropriate physical parameters, such as operating conditions and equipment size (membrane area in this case) to relate the flux to a driving force. The compositions of streams (1) and (2) may be used however, it is better to use the ratio of permeabilities, transport coefficients, or other measures of the inherent separating ability of the device. One can think of a as a flux ratio scaled for a unit driving force ... 

The assumption that the activation cross section varies with neutron energy as 1/v in the thermal neutron region is valid for most (n,y) reactions. The two reactions that deviate the most from the 1/v assumption are Lu(n,y) Lu (typically +0.4%/K) and Eu(n,y) Eu (typically —0.1%/K). The reaction rates for these two reactions, relative to a monitor reaction like Au(n,y) Au, will depend on the thermal neutron temperature in the irradiation channel used. A new set of equations, the Westcott formalism (Westcott 1955), was developed to account for these cases and used the Westcott g T ) factor, which is a measure of the variation of the effective thermal neutron activation cross-section relative to that of a 1/v reaction. In the modified Westcott formalism, the following differences are also included the Qo(a) value of the Hogdahl formalism is replaced by the So(< ) value, and the thermal to epithermal flux ratio, f, is replaced by the modified spectral index, r a) TJTo). To use this formalism with the kg method (De Corte et al. 1994), it is necessary to measure the neutron temperature, r , for each irradiation and a Lu temperature monitor should be irradiated. The Westcott formalism needs to be implemented only when analyzing for Lu and Eu. There are several other non-1/v nuclides Rh, In, Dy, Ir, and Ir, but for these the error... 

For determination of the Ao-factor, gold was used as comparator, which was coirradiated as dilute Au-Al wire. This Au-Al wire should be coirradiated with each sample. It can, however, be converted to any comparator that is found suitable for coirradiation and that has been coirradiated with gold before. To determine the epithermal-to-thermal flux ratio, coinadiation of a zirconium monitor is suitable. The Ao-factors for 68 elements and their relevant gamma lines of 135 analytically interesting radionuclides have been determined and published by De Corte and coworkers. For nearly all of them, the uncertainly is <2%. An overview is given in Table 2 [31]-[33]. 

Permeability A property of materials which expresses the relationship between magnetic induction and magnetizing force. An indication of the relative abUity to conduct magnetic flux. Power factor The ratio of the active power in watts to the apparent power in voltamperes. It is also the cosine of the phase angle between the voltage and current. 

The axial flux peaking factor within the core is 1.4. Two different values of enrichment (typically, 2.5% in the top half and 4.0% in the lower half) in plutonium bearing fuel pins cause the axial flux peak to be located in a region below the high steam quality upper region in the coolant channel, thereby significantly improving the minimum critical heat flux ratio (MCHFR), as compared to what would be achievable with a uniform axial enrichment. 

Equation (9.23) is to be compared with the Feng and Stewart relations (9.4) which describe the fluxes in the same system under non-reactive conditions, The factor (BA coth BA - 1) has the form sketched in Figure 9.2. From the definition of B given by equation (9.19) it is seen chat 9- 0 as and each tend to zero, their ratio remaining equal to Che... 

The ratio Db/Da is a so-called relative sensitivity factor D. This ratio is mostly determined by one element, e. g. the element for insulating samples, silicon, which is one of the main components of glasses. By use of the equation that the sum of the concentrations of all elements is equal to unity, the bulk concentrations can be determined directly from the measured intensities and the known D-factors, if all components of the sample are known. The linearity of the detected intensity and the flux of the sputtered neutrals in IBSCA and SNMS has been demonstrated for silicate glasses [4.253]. For SNMS the lower matrix dependence has been shown for a variety of samples [4.263]. Comparison of normalized SNMS and IBSCA signals for Na and Pb as prominent components of optical glasses shows that a fairly good linear dependence exists (Fig. 4.49). 

The enhancement factor of CO2 defined as ratio of the flux of CO2 with chemical reaction to that without chemical reaction is shown as follows ... 

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