Net flow method

In NEM, a priori knowledge of the process expressed by the decision-maker is incorporated into the optimization routine using four sets of ranking parameters listed below. 

The first parameter gives the relative importance of each objective function or criterion k, expressed as a relative weight (Wk). In this algorithm, the various weights are normalized  

The second parameter refers to the indifference threshold (Qk), which defines the range of variation of each criterion for which it is not possible for the decision-maker to favor the criterion of one solution over the corresponding criterion of another solution. It therefore represents the range of values over which two objective functions are indiscernible. 

The third parameter refers to the preference threshold (Pk). If the difference between two values for a given criterion exceeds this threshold, a preference is given to the better criterion. If the objective is to maximize a particular criterion, then the better solution is that with the larger value for that criterion, and vice versa. 

The fourth parameter refers to the veto threshold (14), which serves to ban a solution relative to another solution if the difference between the values of a criterion is too high to be tolerated. A solution is banned if the veto threshold is violated for at least one of the objective functions, even if the other criteria are acceptable. 

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Operating conditions of gluconic acid production Maximization of overall production rate and the final concentration of the gluconic acid while minimizing the final substrate concentration at the end of fermentation process. Net Flow Method (NFM) Pareto-domain was first found by a procedure which includes an evolutionary algorithm. Halsall-Whitney etd. (2003)... 

Keywords Net flow method, rough set method, thresholds, concordance index, discordance index, preference and non-preference rules, ranking, gluconic acid production. 

Various other evaluation schemes based on the concept of time value of money are also sometimes used. These, together with the Net Present Value and Rate of Return methods, are all grouped together under the title of discounted cash flow methods. 

As flow rates decrease, the perfusion medium in the probe approaches equilibrium with the ECF (Wages et al., 1986). Therefore, the dialysate concentration of an analyte sampled at very lowflow rates more closely approximates the concentration in the extracellular environment (Menacherry et al., 1992). Like no net flux and the zero flow models, this is another steady-state analysis with limited application to transient changes based on behavior or pharmacological manipulations. However, the advent of new techniques in analytical chemistry requiring only small sample volumes from short sampling intervals may signal a potential return to the low flow method. 

The same methods that were explained and applied earlier in this chapter are applicable for replacement analyses. Net-present-worth and discounted-cash-flow methods give the soundest results for maximizing the overall future worth of a concern. However, for the purpose of explaining the basic principles of replacement economic analyses, the simple rate-of-retum-on-investment method of analysis is just as effective as those methods involving the time value of money. Thus, to permit the use of direct illustrations which will not detract from... 

In the present worth (or discounted cash flow) method, each annual net cash flow for a project is discounted to the beginning of the project (year zero), in order to express all cash flows on the same basis. This discounting is done via the following equation ... 

Conventional methods for establishing the existence of active transport are to analyze the effects of metabolic inhibitors, to correlate the rate of metabolism with the extent of ion flow or the concentration ratio between the inside concentration and the outside concentration of the cells, and to measure the current needed in a short-circuited system having identical compositions solution on each side. Measurements indicate that the flow contributing to the short-circuited current, and ary net flow detected are due to active transport, since the electrochemical gradients of all ions are zero (A // = 0, c0 = c,). 

The levelized prices of PV electricity and H2 are derived by net present value cash flow analysis. The net present value cash flow method is described in Appendix A.l. A straight tine, ten-year depreciation schedule is applied with an annual depreciation rate of 9% of capital. The levelized PV electricity and H2 prices are derived by choosing PV electricity and H2 prices to generate a revenue level that results in a cumulative, net cash flow stream with a 0 net present value over the thirty-year capital recovery period. The annual net cash flow streams are discounted at the present value of the 6%-discount rate. Investment funds are allocated in year 1 construction occurs in year 2 and H2 cash flow begins in year 3. The modular design of PV electrolysis plants and H2 distribution systems enables the rapid initiation of H2 marketing and cash flow. 

The levelized PV electricity and H2 prices presented in this study are derived from Eq. 6 by choosing the electricity or H2 price level for the revenue component that produces a zero net present value for the net cash flow streams over the invest ment period, which in this case is equivalent to the internal rate of return. The esti mation of levelized PV electricity and H2 prices by the net present value cash flow method insures that all creditors and shareholders receive their expected rates of return. 

These difficulties have been alleviated by performing the experiments in a different manner (also, membranes are a lot better than they used to be). One way is to simply apply a pressure, ft, equal to the osmotic pressure, to the solution side of the membrane, as illustrated schematically in Figure 12-6. This would prevent any net flow. Alternatively, the deflection of the membrane could be used to measure the initial osmotic pressure directly. Molecules could still diffuse in each direction, however, but both methods provide reliable measurements of n in just a few minutes, before there has been any appreciable diffusion of solvent or solute. 

We can now employ our usual methods to calculate, at any point in the tube, the net flows of species 1 and 2 across a unit area. If we take a plane perpendicular to the direction of the concentration gradients (i.e., the X axis) then there will be a net flow of species 1 across this plane owing to the fact that there is a difference in the number of molecules of species 1 that strike it from opposite sides (Fig. VIII.5). By making the usual assumption of local equilibrium distributions we can use our formula [Eq. (VII.6.6)] for the number of collisions per unit area per second. We then have for the number of collisions of species 1 with a unit area per second, made on the high-concentration side,... 

At typical flow rates, the concentration in the dialysate, Cout, is less than the actual concentration in the extracellular fluid, Cext (23). The ratio of Cout/Cext is defined as relative recovery, R, and must be considered for probe calibration and sampling optimization. In vitro, R is easily calculated because the dialysate and the extracellular fluid are homogenous therefore, probe calibration is easily obtained. However, in in vivo studies, calculation of R is difficult because of the active removal of neurotransmitters by uptake and tortuosity. Movement of analytes is impeded by tissue that surrounds the probe, and this movement cannot be easily accounted for with in vitro calibrations. Therefore, the most common method to determine concentrations in vivo is the zero-net flux method, in which known analyte concentrations are added to the perfusate (Cin), and then the analyte concentration is measured at the probe outlet (Cout)- The difference between analyte concentration at the inlet and outlet is used to establish the actual analyte concentration in the tissue, and the relative recovery rate can be calculated. This calibration method can be used to estimate basal levels of neurotransmitters. For example, the zero-net flux method has been used to determine that basal concentrations of dopamine are approximately 1-3.5 nM (24, 25). Although basal level concentrations... 

The energy balance equations for all the zones need to be established to solve this radiative exchange problem. This is done using the net-radiation method introduced by G. Poljak [5.49], This yields a system of linear equations that, when solved, deliver the unknown temperatures and heat flows. With simple... 

Suppose we place a semipermeable membrane between a saline (salt) solution and pure water. If the saline solution is pressurized under a greater pressure than its osmotic pressure, the direction of flow can be reversed. That is, the net flow of water molecules will be from the saline solution through the membrane into the pure water. This process is called reverse osmosis. The membrane usually consists of cellulose acetate or hollow fibers of a material structurally similar to nylon. This method has been used for the purification of brackish (mildly saline) water. It has the economic advantages of low cost, ease of apparatus construction, and simplicity of operation. Because this method of water purification requires no heat, it has a great advantage over distillation. 

Net Flow and Rough Sets Two Methods for Ranking the Pareto Domain 191... 

Specifically, rest of this chapter begins by very briefly considering MOO in general, followed by a more detailed discussion of the algorithm of net flow and rough set methods, whilst illustrating these with simple examples. The last section of the chapter is devoted to the application of this method to the production of gluconic acid. 

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