Concentric parametric studies

Parametric studies showed that mass diffusion in the gas phase could be neglected under most conditions. The calculations also show that the selection of the hypergolic combination (i.e., the gaseous oxidizer and the propellant system) fixes all of the parameters except the initial temperature and the oxidizer concentration. A general solution of the model shows that the ignition-delay time is approximately rated to the gaseous oxidizer concentration by the relation... 

Since the present study aims at carrying out the investigation of the break-down phenomenon and searching for the possible mechanism of the phenomenon, we have chosen the similar condition as in [1] for the wall shear stress to induce break-down The reference temperature in the degradation studies was 60 °C. This value may be lower than the value used in a typical DHS. In a low-pressure system, however, it was necessary to use lower the temperature to avoid the formation of bubbles. For parametric studies, one of the variables was varied while the other variables were fixed at the reference condition (Tanperature 60 °C Re 8,000 Surfactant concentration 200ppm Volume of solution charged 0.010 m ). 

Parametric studies on the impact of total flow rate, relative flow rates and concentration on the flow pattern within droplets... 

In the following section, the micellization model and the free-energy expression used in ref 6 are described. In section ID, the cmc and C t are calculated numerically for various values of o. Because the numerical calculations for a complete parametric study would be too lengthy, approximate, analytical relations for the two concentrations are developed in section IV. Computations based on these relations show that, of all the parameters, a is the only one which drastically affects the ratio between cmc and Cme The last section emphasizes again that Ccrit has a value close to the conventional cmc as long as the expression used for the free energy is a physically acceptable one. 

KwendakwemS, N.J. and Boehm, R.F., Parametric Study of Mixed Convection in a Porous Medium Between Vertical Concentric Cylinders , J. Heat Transfer, Vol. 113, pp. 128-134, 1991. 

A non-isothermal dynamic model has been developed for a shallow fulidized bed combustor, which can be used to predict, at least qualitatively, the transient and steady-state characteristics of such systems. Parametric studies have been conducted to examine the effects of excess air flow rate, bubble size and carbon feed rate. It has been shown that an appreciable carbon concentration gradient does exist in the bed. This explains why it is necessary to use multiple feed points in large fluidized bed combustors. A surprising result obtained is that the temperature iii the bed is essentially uniform under all conditions studied even though the carbon concentration is not uniform laterally. 

A complete parametric study of the unsteady state mass transfer model clearly shows that tp, the pulse period, 4, the polarization, A, the aspect ratio, and DF, the duty factor have a profound effect on the evolution and the final shape of the deposit. Large polarization s and aspect ratios lead to deposition that is mass transfer controlled. This results in keyhole formation, as the concentration gradient inside a high aspect ratio trench is very large. On the other hand, when the deposition is kinetically controlled (i.e. for small values of polarization and aspect ratio) the gradient down the length of the trench is much smaller and deposition proceeds at nearly the bulk concentration. This leads to conformal deposition, as there is negligible variation in the deposition rate at the mouth and at the bottom of the trench. 

In the CAN-BD process, the characteristics of the powders generated (e.g., particle size and morphology, etc.) can be affected by the process operating parameters, i.e., drying temperature, CO2 pressure, solute concentration, flow rates of dense CO2 and aqueous solution, etc. Parametric studies were conducted to determine the particle characteristics that are most sensitive to process parameters. 

Parametric studies utilizing mannitol and myo-inositol indicate that smaller particles are obtained as the solute concentration decreases or the ratio of dense CO2 to liquid solution flow rates increases. 

The structure of this chapter is as follows. In the next section a comparison of the FBR and PBMR will be presented using a simplified ID modeL Advantages and drawbacks of the PBMR will be illustrated. Subsequently, a more detailed 2D model will be developed to study important aspects of radial mass and heat transfer, as well as scale-up problems that might occur in a PBMR. In the last section a short outlook to more sophisticated 3D membrane reactor models is given. Such models are still not suitable for extensive parametric studies. However, they enable a deeper investigation of local velocity and concentration profiles that develop in such reactors. 

DeMontigny, D., Tontiwachwuthikul, P., Chakma, A., 2001, Parametric Studies of Carbon Dioxide Absorption into ffighly Concentrated Monoethanolamine Solutions, Can. J. Chem. Eng., 79,137-142. 

During normal operation of the reactor (fuel temperature of approximately 1000 K), it is clearly impossible to have liquid water present. Nevertheless, water vapor could inadvertently enter the coolant through some structural failure in the system. Lacking knowledge as to credible values of water vapor content, a parametric study was conducted to determine the concentration of water in the void region of the graphite foam that would yield maximum reactivity. 

Figures 13.37 and 13.38 demonstrate that the shear thinning parameters t]o, , S, Kc, and X have straightforward dependences on c and M. The dependences are in part system dependent. One infers that measurements of r] K) at fixed M and a limited number of values of c, followed by determination of the c-dependence of the fitting parameters, should allow quantitative calculation of t](K) at intermediate concentrations not studied experimentally, and similarly if the roles of M and c are interchanged. Extrapolation as always is fraught with additional uncertainty. Interpolation for t](k) via interpolation on its parameters is the modem equivalent of the master curve approach of the last century, except that parametric interpolation can be effective in systems in which a master curve would be inappropriate.

Beside the RDE extraction performances, their stability represents a crucial point that needs to be elucidated. While long-term emulsion stability should be ensured for the therapeutic applications, only short-term stability has to be achieved for environmental applications. For the later applications an emulsion breakage (splitting or coalescence) step is required in the process in order to separate the toxic-loaded emulsion into a toxic-concentrated aqueous solution, which is then valorized and the free oily phase is recycled in the emulsification step. These opposite requirements need more extensive parametric study to determine any delicate compromises. 

Results of nuclear calculations. The results of the parametric study are summarized in Table 24-6 for all cases. The criti< al concentrations and conversion ratios for the cases using thorium as the fertile material are graphed in Figs. 24-21 through 24-25. 

Temperature Two modes of temperature parametric-pumping cycles have been defined—direct and recuperative. In direct mode, an adsorbent column is heated and cooled while the fluid feed is pumped forward and backward through the bed from reservoirs at each end. When the feed is a binary fluid, one component will concentrate in one reservoir and one in the other. In recuperative mode, the heating and cooling takes place outside the adsorbent column. Parametric pumping, thermal and pH modes, have been widely studied for separation of liquid mixtures. However, the primary success for separating gas mixtures in thermal mode has been the separation of propane/ethane on activated carbon [Jencziewski and Myers, Ind. Eng. Chem. Fundam., 9, 216-221 (1970)] and of air/S02 on silica gel... 

The second chapter is devoted to computing the Betti numbers of Hilbert schemes of points. The main tool we want to use are the Weil conjectures. In section 2.1 we will study the structure of the closed subscheme of X which parametrizes subschemes of length nonl concentrated in a variable point of X. We will show that (X )rei is a locally trivial fibre bundle over X in the Zariski topology with fibre Hilbn( [[xi,... arj]]). We will then also globalize the stratification of Hilbn( [[xi,..., x ]]) from section 1.3 to a stratification of Some of the strata parametrize higher order data of smooth m-dimensional subvarieties Y C X for m < d. In chapter 3 we will study natural smooth compactifications of these strata. 

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