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The New Model

The parameters utilized for this approach are from Breck [57] for the gases He, H2, CO2, O2, N2 and CH4, Poling [58] for the gases CO, Ar, C2H j, n-CsH and SFe, and the universal force field (UFF) values [59] are used for the surface atoms, as summarized in Table 5.2. This potential difference has been termed the suction energy since a positive W translates to a suction force of the molecule from the outside to the inside of the pore, while a negative W translates to a repulsive force directing the molecule away from the pore [23]. From this, a new transport mechanism is proposed in [23] as suction diffusion , where enhanced velocities are predicted as the gas molecules are sucked into the pore. [Pg.99]

The three most common diffusion mechanisms known as activated diffusion, surface diffusion and Knudsen diffusion, usually dominate in small pores (d 3 A), medium pores (3 A d 10 A) and large pores (10 A d 500 A) for light gases, respectively. Separation by differences in diffusivity and/or differences in solubihty can be enhanced [Pg.99]

The first observation to be made from the results in Table 5.3 is that the minimum pore sizes for barrier-free transport of each gas are in the same order as the kinetic diameter with slightly different values because the model takes into acconnt the interaction with [Pg.100]


However, this simple model of a periodic motion occupied the central position in the theory of oscillations from its very beginning (Galileo) up to the time of Poincar6, when it was replaced by the new model—the limit cycle. [Pg.328]

A study of the effect of the mesophase layer on the thermomechanical behaviour and the transfer mechanism of loads between phases of composites will be presented in this study. Suitable theoretical models shall be presented, where the mesophase is taken into consideration as an additional intermediate phase. To a first approximation the mesophase material is considered as a homogeneous isotropic one, while, in further approximations, more sophisticated models have been developed, in which the mesophase material is considered as an inhomogeneous material with progressively varying properties between inclusions and matrix. Thus, improvements of the basic Hashin-Rosen models have been incorporated, making the new models more flexible and suitable to describe the real behaviour of composites. [Pg.151]

Although many interface models have been given so far, they are too qualitative and we can hardly connect them to the mechanics and mechanism of carbon black reinforcement of rubbers. On the other hand, many kinds of theories have also been proposed to explain the phenomena, but most of them deal only with a part of the phenomena and they could not totally answer the above four questions. The author has proposed a new interface model and theory to understand the mechanics and mechanism of carbon black reinforcement of rubbers based on the finite element method (FEM) stress analysis of the filled system, in journals and a book. In the new model and theory, the importance of carbon gel (bound rubber) in carbon black reinforcement of rubbers is emphasized repeatedly. Actually, it is not too much to say that the existence of bound rubber and its changeable and deformable characters depending on the magnitude of extension are the essence of carbon black reinforcement of rubbers. [Pg.519]

The new interface model and the concept for the carbon black reinforcement proposed by the author fundamentally combine the structure of the carbon gel (bound mbber) with the mechanical behavior of the filled system, based on the stress analysis (FEM). As shown in Figure 18.6, the new model has a double-layer stmcture of bound rubber, consisting of the inner polymer layer of the glassy state (glassy hard or GH layer) and the outer polymer layer (sticky hard or SH layer). Molecular motion is strictly constrained in the GH layer and considerably constrained in the SH layer compared with unfilled rubber vulcanizate. Figure 18.7 is the more detailed representation to show molecular packing in both layers according to their molecular mobility estimated from the pulsed-NMR measurement. [Pg.522]

Assumption in the new model that there is hardly any or no chemical cross-Unks in the SH layer, only makes the changeable and deformable characteristics of the SH layer possible. This assumption has almost been verified experimentally. [Pg.538]

There are two words to watch out for or equivalent. What is called equivalent by a designer or contractor may not be equivalent to the laboratory operator. Sometimes this problem arises when a specified item has been superseded by a new and improved model. However new or improved the new model may be, there could be some reason why it would not be right for a particular application. Any substitution must be viewed as suspect. It is always wise, of course, to listen carefully to all suggestions from building professionals and evaluate the reasons they give for a proposed change, but nothing should go imquestioned. [Pg.96]

In contrast to the pre-existing models that merely portrayed membrane potentials, the new generation of models calculated the ion fluxes that give rise to the changes in cell electrical potential. Thus, the new models provided the core foundation for a mechanistic description of cell function. Their concept was applied to cardiac cells by Denis Noble in 1960. [Pg.136]

The first membrane model to be widely accepted was that proposed by Danielli and Davson in 1935 [528]. On the basis of the observation that proteins could be adsorbed to oil droplets obtained from mackerel eggs and other research, the two scientists at University College in London proposed the sandwich of lipids model (Fig. 7.2), where a bilayer is covered on both sides by a layer of protein. The model underwent revisions over the years, as more was learned from electron microscopic and X-ray diffraction studies. It was eventually replaced in the 1970s by the current model of the membrane, known as the fluid mosaic model, proposed by Singer and Nicolson [529,530]. In the new model (Fig. 7.3), the lipid bilayer was retained, but the proteins were proposed to be globular and to freely float within the lipid bilayer, some spanning the entire bilayer. [Pg.121]

The goal is to discover things we never knew or expected, and to see relationships and connections among the elements, whether previously suspected or not. It follows that this process is not driven by hypothesis and should be as model-independent as possible. We should use the unprecedented experimental opportunities that the genome sequences provide to take a fresh, comprehensive and open-minded look at every question in biology. If we succeed, we can expect that many of the new models that emerge will defy conventional wisdom , (Brown and Botstein, 1999). [Pg.186]

An initial suggestion made by Ford Doolittle shows a jumble of interconnections between the lines of development, rather than simple branches in the phylogenetic tree. These interconnections resemble a mycelium and have almost nothing in common with the original model, except for the termini of the three kingdoms. In a review article in Science, Elizabeth Pennisi (2001) chose the colourful metaphor of a tangled bramble bush to describe the new model. [Pg.277]

Fig. 5 Initial fold length L against undercooling AT = To - T for both melt- and solution-crystallized polyethylene, from different solvents [16]. Dashed line gives previous calculations (Model A [9], old model in Fig. 4), solid line shows the results from the new model in Fig. 4 after re-adjusting the energy of fusion per - CH2 - unit from E= 1.07 to E- 1.42 kcal/mol... Fig. 5 Initial fold length L against undercooling AT = To - T for both melt- and solution-crystallized polyethylene, from different solvents [16]. Dashed line gives previous calculations (Model A [9], old model in Fig. 4), solid line shows the results from the new model in Fig. 4 after re-adjusting the energy of fusion per - CH2 - unit from E= 1.07 to E- 1.42 kcal/mol...
One year later, the new model took its final name of Extended Hiickel Theory, and was cast in the concise, attractively simple form that has survived to date in a comprehensive paper on hydrocarbons, Roald Hoffmann (4) was able to show that many different properties of these compounds could be correctly calculated, thus establishing the operative validity of the method. [Pg.3]

The new model is called quasi-ballistic because the electron motion in the quasi-free state is partly ballistic—that is, not fully diffusive, due to fast trapping. It is intended to be applied to low- and intermediate-mobility liquids, where the mobility in the trapped state is negligible. According to this, the mean... [Pg.340]

Brabender make a whole range of instruments for testing flour. These instruments are the standard ones in use in the UK, Germany and North America. The company has recently produced new versions of these instruments that use electronic measuring systems rather than the mechanical systems previously employed. The new models use the same name but with the suffix E. Thus, the new model Extensograph is the Extensograph-E. [Pg.143]

We obtain an r.m.s. deviation of 0.84 kcal/mol with an optimal a of 0.181. One can also note the similarity between the a value of this model and that of the two-parameter model with a free a and /3. This suggests that the model is robust in the sense that the actual polar and non-polar free energy contributions are more or less invariant, as long as deviations from linear response are taken into account in a proper way. The FEP-derived model could be considered preferable to the two-parameter model since it contains only one free parameter, viz. oc. The results of adding a constant yto the new model was also investigated. Remarkably, the optimal value for such a y was found to be -0.02 kcal/mol, i.e. virtually zero. [Pg.180]

While the regression coefficient (r2 = 0.78) was lower than the one in previous models (e.g., Eq. 18), the new model was satisfying from a mechanistic point of view. [Pg.469]

The new model has also been applied to the calculation of thermally averaged probability density functions for the out-of-plane inversion motion of the CH and H3O ions [9]. Such probability densities can be obtained experimentally by means of Coulomb Explosion Imaging (CEI) techniques (see, for example, Refs. [10,11]), and the results in Ref. [9] will be useful in the interpretation of the resulting images, just as analogous calculations of the bending probability distribution for the CHj ion were instrumental in the interpretation of its CEI images (see Refs. [9,12] and references therein). [Pg.210]

The new melting model presented in this section qualitatively fits the experimental data observed by many previous researchers. Like the Tadmor and Klein model [8], this model is based on simplistic assumptions and linear mathematics for the melt films. The new model, however, does not require the reorganization of the solid bed like the Tadmor and Klein model. Furthermore, the new model allows viscous dissipation and melting in all four melt films, and does not restrict all melting to the Zone C film. Melting in the Zone D melt film becomes highly important when the boundary conditions are switched from barrel rotation to the actual conditions of screw rotation. [Pg.218]

A new model of the cotton-dust analyzer was constructed to overcome some of the shortcomings of the prototype. It was more compact and easier to operate than the original machine. The sizing-screen arrangement in the new model was more accessible than in the original machine to facilitate the evaluation of various screen sizes. It was also equipped with an air regulator to maintain a constant air pressure on the spray bar for Improved airflow characteristics. Also, a high-efficiency particulate air... [Pg.54]


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