Diffusivities comparison with literature data

Park, et al. used holographic relaxation spectroscopy to measure Dp of a dye and a labeled protein through polyacrylamide gels over distances orders of magnitude larger than any structure in the gel(105). On comparison with literature data on other small diffusants in the same medium. Park, et al. found... 

These two thin liquid films, which are also called diffusion films, diffusion layers, or Nernst films, have thicknesses that range between 10 and 10 cm (in this chapter centimeter-gram-second (CGS) units are used, since most published data on diffusion and extraction kinetics are reported in these units comparison with literature values is, therefore, straightforward). 

Assuming a specimen thickness of 23 micrometers we calculated permeabilities and diffusion coefficients for comparison with literature values. Our data and the data used for comparison are listed in Table III, which is organized along the same lines as Yasuda s compilation (13). Our values compare well with the limited data available (14-18) when one makes allowance for the differences in film morphology that are likely to exist. 

Comparison may be made with literature data on solution viscosities. The probe diffusion coefficient does not simply track the solution viscosity instead. Dpi] typically increases markedly with increasing polymer concentration and molecular weight. The probe rotational diffusion coefficient, for which there are Umited sets of experiments, either has the same concentration dependence as the viscosity or, in other systems, has a concentration dependence that is significantly weaker than the concentration dependence of the viscosity or the probe translational diffusion coefficient. 

The analysis of the literature data shows that zeolites modified with nobel metals are among perspective catalysts for this process. The main drawbacks related to these catalysts are rather low efficiency and selectivity. The low efficiency is connected with intracrystalline diffusion limitations in zeolitic porous system. Thus, the effectiveness factor for transformation of n-alkanes over mordenite calculated basing on Thiele model pointed that only 30% of zeolitic pore system are involved in the catalytic reaction [1], On the other hand, lower selectivity in the case of longer alkanes is due to their easier cracking in comparison to shorter alkanes. 

Most currently available diffusion coefficient data are for polyolefins. Appendix I provides a comprehensive list of Devalues taken from the scientific literature for LDPE, HDPE and PP. The diffusion data presented in the three tables of Appendix I were critically (i.e. not based on subjective decisions) selected from several hundreds of papers and reports published over the last four decades. A similar publication, but with far less data, was published more than 15 years ago (Flynn, 1982). In comparison with Flynn (1982) the criteria used to select the data in Appendix I were primarily based on considerations linked to relevance of the data for predicting migration into and from food packaging made from these polymers. The inclusion of experimental diffusion data in the present collection required that ... 

Thiele et al.8°) modeled the initial polymerization of styrene. A comparison with the experiment showed that there is a satisfactory correlation of W and P up to q < 0.4. On the basis of the literature and experimental data, it has been concluded that kt in isothermal suspension polymerization becomes diffusion-controlled at q > 0.25 initiation efficiency if) becomes diffusion-controlled at q > 0.4 and kp and km become diffusion-controlled at q > 0.75. 

The propagation and termination rate constants have been determined for many systems (5,12,43-46). In most cases, the propagation rate constant is lower than that for a reaction carried out in the same conditions but without a template. The termination rate constant in the template polymerization is much lower in comparison with the blank reaction. Retarded termination may be caused by retarded segmental diffusion of the template-boimd radicals. This leads to the template increasing the overall rate of polymerization. Much experimental data from the literature confirm this, and it is sometimes called the kinetic template effect. 

Current numerical efforts are focused on LES benchmarking. Nonreacting jets and jet flames from the Sandia database library will be stndied. Combustion models will initially be based on flamelet concepts, but models which address finite-rate chemistry will also be considered [13, 14]. Flame, emissions, and noise predictions will be compared to experimental data. Predictions of swirl combustor flowfields with comparison to data from the literature and the authors own experiments are also underway. Ear-field sound predictions of diffuser flow are currently underway. Coupled diffuser-combustor studies addressing unsteady inlet flow effects and trapped-vortex combustor studies focusing on cavity acoustic resonance effects are planned. 

The method developed here for the description of chemical equilibria including adsorption on charged surfaces was applied to interpret phosphate adsorption on iron oxide (9), and to study electrical double-layer properties in simple electrolytes (6), and adsorption of metal ions on iron oxide (10). The mathematical formulation was combined with a procedure for determining constants from experimental data in a comparison of four different models for the surface/solution interface a constant-capacitance double-layer model, a diffuse double-layer model, the triplelayer model described here, and the Stem model (11). The reader is referred to the Literature Cited for an elaboration on the applications. 

Therefore, to evaluate the reliability of the SW potential, we must, instead, examine how good the agreement is between properties obtained using it and from experiments or first-principles simulations. Such a comparison is made here on the basis of an extensive literature search of experiments, first-principles simulations and other empirical potential simulations done on liquid silicon. We compare results for density (p), structure factor (S(q)), radial distribution function (g(r)), and diffusivity (D) obtained from various reports with the SW silicon data. 

The permeation mechanisms depend mainly on the chemical nature of the polymer backbone and the characteristics of the diffusing molecules. It is well-known that diffusing gas molecules, except for CO, have no, or at least very few, interactions with polymer materials. It is important to know the conditions of permeation measurements carried out however this information is unfortunately often forgotten in the literature. Added to this fact, few data about permeation in literature are available as well as in great diversity of units which makes it difficult to establish comparisons. 

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