Dave model

The Dave model considers a force balance on a porous medium (the fiber bed). The total force from the autoclave pressure acting on the medium is countered by both the force due to the springlike behavior of the fiber network and the hydrostatic force due to the liquid resin pressure within the porous fiber bed. Borrowing from consolidation theories developed for the compaction of soils [23,24], the Dave model describes one-dimensional consolidation... 

TRACE II Toxic Release Analysis of Chemical Emissions Safer Emergency Systems, Inc. Darlene Davis Dave Dillehay 756 Lakefield Road Westlake Villa, CA 91361 (818) 707-2777 Models toxic gas and flammable vapor cloud dispersion. Intended for risk assessment and planning purposes, rather than realtime emergencies. 

Support for this work by 3M Company and permission to publish is gratefully acknowledged. We thank Dave Lindemann for the finite-element modeling and 3M s Division Engineering, especially Don Peacock, for all their work. Bob Maline of 3M s Specialty Materials Division was supervisor of pilot plant operations. 

Wang TSC, Li SW (1977) Clay minerals as heterogeneous catalysts in preparation of model humic substances. Z Pfanzenemaehr Bodenkd 140 669-676 Weed SB, Dave CB, Cook MG (1969) Weathering of micas by fungi. Soil Sci Soc... 

There are a number of estimates of the actinic flux at various wavelengths and solar zenith angles in the literature (e.g., see references in Madronich, 1987, 1993). Clearly, these all involve certain assumptions about the amounts and distribution of 03 and the concentration and nature (e.g., size distribution and composition) of particles which determine their light scattering and absorption properties. Historically, one of the most widely used data sets for actinic fluxes at the earth s surface is that of Peterson (1976), who recalculated these solar fluxes from 290 to 700 nm using a radiative transfer model developed by Dave (1972). Demerjian et al. (1980) then applied them to the photolysis of some important atmospheric species. In this model, molecular scattering, absorption due to 03, H20, 02, and C02, and scattering and absorption by particles are taken into account. 

MgBr+/IBT(a) Dave et al. [24] Malkin s autocatalytic model Adiabatic temperature analyzed by regression analysis 30.2 1.49 x 104 2.17... 

In overcoming the shortcomings of the earlier models, Dave et al. [21,22] proposed a comprehensive three-dimensional consolidation and resin flow model that can be used to predict the following parameters during cure (1) the resin pressure and velocity profiles inside the composite as a function of position and time, (2) the consolidation profile of the laminate as a function of position and time, and (3) resin content profile as a function of position and time. 

Dave, R., Kardos, J., Dudukovic, M. Process Modeling of Thermosetting Matrix Composites A Guide For Autoclave Cure Cycle Selection, American Society for Composites, First Technical Conference, Dayton, OH, Oct. 1986... 

Probably the first major publication of a process model for the autoclave curing process is one by Springer and Loos [14]. Their model is still the basis, in structure if not in detail, for many autoclave cure models. There is little information about results obtained by the use of this model only instructions on how to use it for trial and error cure cycle development. Lee [16], however, used a very similar model, modified to run on a personal computer, to do a parametric study on variables affecting the autoclave cure. A cure model developed by Pursley was used by Kays in parametric studies for thick graphite epoxy laminates [18]. Quantitative data on the reduction in cure cycle time obtained by Kays was not available, but he did achieve about a 25 percent reduction in cycle time for thick laminates based on historical experience. A model developed by Dave et al. [17] was used to do parametric studies and develop general rules for the prevention of voids in composites. Although the value of this sort of information is difficult to assess, especially without production trials, there is a potential impact on rejection rates. 

Morin, K. A., Cheery, J. A., Dave, N. K Lim, T. P and Vivyurka, A. J., 1988. Migration of acidic ground water seepage from uranium-tailings impoundments. 1. Field study and conceptual hydrogeochemical model. J. Contaminant Hydrology, v. 2, pp. 271-303. 

We thank John Bendler for performing the molecular modeling calculations and for many helpful discussions. Monty Alger and Lorraine Rogers provided some of the permeability data, while John Campbell, Dave Dardaris, Gary Faler, Ed Fewkes, Paul Howson, Rick Joyce, Jerry Lynch and John Maxam contributed to the results described in this report. 

Braslau, N., and J. V. Dave (1973). Effect of aerosols on the transfer of solar energy through realistic model atmospheres, Parts I and II. J. Appl Meterorol. 12, 601-619. 

Abraham and Dave have found a striking prediction of the drop model, which demonstrates that it really should not be applicable to a small cluster. In Eq. (38) of the drop model, we interpreted Ff — iFb of Eq. (37) as the area of a cluster times the surface free energy per unit area in bulk material. It could just as well be interpreted as the number of molecules on the cluster surface times the surface free energy per surface atom in bulk material. When this is done, one can calculate the number of surface molecules in a cluster of i molecules. Abraham pointed out that the drop model then regards a 10-molecule cluster as having 20 surface molecules ... 

Dave, R., Kardos, J. L. and Dudukovic, M. R, 1987. A model for resin flow during composite processing. Part 1 General mathematical development . Polymer Composites, 8, 29-38. 

Dave, R., 1990. A unified approach to modelling resin flow during composite processing , Journal of Composite Materials, 24, 22-41. 

The FCC unit comprises of two basic parts, a reactor/riser in which hydrocarbon cracking reactions occur and a regenerator in which catalyst regains its activity by burning coke deposited on it during cracking. More detailed description of the process is available in Avidan and Shinnar (1990). Recently, Dave and Saraf (2(X)2) reviewed the extensive literature available on modelling of industrial FCC units. 

Dave and Saraf (2002) modified the original scheme of Ancheyta et al. (1999) by assuming gasoline and LPG also convert to coke. Figure 1 presents the modified kinetic study, used in the present work. Since rate constants for this model are dependent upon feed quality, they are obtained by tuning industrial data available. In the present work, five lump kinetic model developed by Dave and Saraf (2002) is used for multi objective analysis for objective functions gasoline production maximisation versus minimisation of CO emission from regenerator. 

Dave and Saraf (2002) described regenerator as two-region (the dense bed and the dilute phase) model, essentially following the scheme of Krishna et al. (1985) with some modification. Bulk of the coke combustion reaction occurs in the dense bed and the dilute phase is the region above the dense bed, after burning of carbon monoxide and catalyst entrainment are the main effects of this section. The dense bed is modelled as a... 

It should be noted that using five lump model (Dave and Saraf, 2002), maximisation of conversion is equivalent to maximisation of gasoline conversion. 

It should be noted that again five lump model (Dave and Saraf, 2002) is used. It was assumed that composition of feed is maintained constant by fixing recycle ratio. Appropriate bounds on the decision variables are specified and the constraints for this problem are same as that are listed in problem 1. 

Dave, D.J. and Saraf, D.N., 2002, A model suitable for rating and optimization of industrial FCC units, selected for publication in Indian Chemical Engineer. 

A. Patel, A. Agrawal, and R. Dave, Investigation of the effects of process variables on derived properties of spray dried solid-dispersions using polymer based response surface model and ensemble artificial neural network models, Eur. J. Pharm. Biopharm., 86,404-417,2014. 

In the emerging model, procurement departments must act more strategically. We described their traditional role in Chapter 14. The procurement function is often the interface between supply chain partners, and partnerships will make new demands on the fxmction. Dave Malmberg of CGR Management Consultants has defined four stages marking the evolution of the procurement function s role. 

Epstein CB, Waddle JA, Hale W, Dave Y, Thornton TL, Gamer HR, et al. Genomewide responses to mitochondrial dysfunction. Mol Biol Cell 2001 12 297-308. Goldstein AL, McCusker JH. Development of Saccharomyces cerevisiae as a model pathogen a system for the genetic identification of gene products required for survival in the mammaUan host environment. Genetics 2001 159 499-513. 

The author wishes to acknowledge the contribution of Arun Ranade of Particle Technology Inc. who assembled and tested the prototype instrument and Monash Kochar of Brookhaven who built the production model under the supervision of Walter Tscharnuter. Experimental work was carried out by Tom Ledwandowski of Du Pont under the supervision of Dave Fields. The author also wishes to thank Reg Davies for his support for this project and to the Du Pont Company for permission to publish. 

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