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Wall geometries

Wagner equation Wagner number Wakamatsu reaction Waldhof fermentor Walkman Wallace plasticity Wallach procedure Wall baffles Wallboard Wall geometries Wallpaper paste Wallpaper pastes Wallpapers Wall plaster Walnut oil... [Pg.1062]

Wall Geometries. Rougher-than-rough waU geometries can reduce transmission probabUities in Knudsen flow by as much as 25% compared to the so-caUed rough-waU cosine reflection (34,35). For this and other reasons, conductance calculations that claim accuracy beyond a few percent may not be realistic. [Pg.373]

The advent of the atomic force microscope has allowed surface properties at nearly molecular length scales to be measured directly for the first time. Recently, a method has been proposed whereby a small ( 3.5 /nn) particle is attached to the cantilever tip of the commercially available, Nanoscope II AFM [67,68]. The particles are attached with an epoxy resin. When the cantilever tip is placed close to a planar surface, the AFM measures directly the interaction force between the particle and the surface. A primary difference between this technique and the surface forces apparatus (SFA) is the size of the substrates, since the SFA generally requires smooth surfaces approximately 2 cm in diameter. Other differences are discussed by Ducker et al. [68]. For our purposes, it suffices to note that the AFM method explicitly incorporates the particle-wall geometry that is the focus of this chapter. [Pg.283]

Using the previous equation for beam bending it is then possible to relate force values to cell wall geometry in foams. Vincent (2004) has measured the distribution/ spectrum of force drops/events from crisp and crunchy cereal foam products, and has foxmd that crisp materials typically showed fracture drops between 0.05 N to 5 N, whereas foams classified as crunchy gave larger force drops in the region of 5-50 N. Substituting these values into the above equations Luyten and van Vhet (2006) have defined the upper and lower values of wall thickness and pore sizes for crisp cereal foams ... [Pg.497]

The variation of the friction with wall geometry, interaction potentials, temperature, velocity, and other parameters has been determined with simulations using simple spherical or short-chain molecules to model the monolayer [24,25,30,61,194]. In all cases, the shear stress shows a linear dependence on pressure that is consistent with Eq. (2) up to the gigapascal pressures expected in real contacts. Moreover, the friction is relatively insensitive to parameters that are not controlled in typical experiments, such as the orientation of crystalline walls, the direction of sliding, the density of the layer, the length of the hydrocarbon chains, and so on. Variations are of order 20%, which is comparable to variations in results from different laboratories [44,217]. Larger variations are only seen for commensurate walls, which may also exhibit a nonlinear pressure dependence [218]. [Pg.243]

Fig. 4. Structure and coordination of the Cu2+ cation located on top of the six-member ring on the zeolite channel wall. Geometries optimized with various models. Fig. 4. Structure and coordination of the Cu2+ cation located on top of the six-member ring on the zeolite channel wall. Geometries optimized with various models.
Changes in the filling pressure of the ventricle (preload) move the end-diastoHc point along the unique end-diastoHc pressure-volume relation (EDPVR), which represents the passive filling mechanics of the chamber that are determined primarily by the thick-walled geometry and nonlinear elasticity of the resting... [Pg.941]

Streeter, D.D., Jr. and Hanna, W.T., Engineering mechanics for successive states in canine left ventricular myocardium I. Cavity and wall geometry, Circ. Res., 33,639-655,1973. [Pg.951]

The times needed to numerically solve the equations of the two models were found to differ by orders of magnitude. This makes the mean-field description an especially promising method for a fast evaluation of reactor designs. When developing a microreaction system it is often unclear how exactly the properties of the channel walls (geometry, thermal conductivity) influence the reaction performance. Usually, the goal is to achieve a temperature distribution as uniform as possible, in order to suppress unwanted side reactions and to increase... [Pg.46]

Numerous workers have described the role of wall-slip effects on measurements made with conventional smooth-walled geometries [Barnes, 1995]. Slip can occur in suspensions at high (ca. 60%) solids volume fiaction, and can involve fluctuating torque in a rotational viscometer under steady... [Pg.52]

The value of the heat emission coefficient depends on various factors and is a function of many derivatives. The heat emission coefficient is mainly determined by the following factors 1) heat carrier-type (gas, steam, droplets of liquid) 2) the type of liquid flow (free or forced flow) 3) wall geometry (length, diameter, and so on) 4) state and properties of a liquid (temperature, pressure, density, heat capacity, heat conductivity, viscosity) 5) motion parameters (flow rate) and 6) wall temperature. [Pg.77]

Of particular importance is the assumption of thin-walled geometry. From Eq. (7.3) we see that the pressure is independent of the z coordinate. Consequently, the finite element utilized for pressure calculation need have no thickness. That is, the element is a plane shell—generally a triangle or quadrilateral. This has great implications for users of plastics CAE. It means that a finite element model of the component is required that has no thickness. In the past this was not a problem. Almost all common CAD systems were using surface or wireframe modeling and thickness was never shown explicitly. The path from the CAD model to the FEA model was clear and direct. [Pg.588]

Figure 10. Undeformed shape of the free wall of a normal rat left ventricle. The network superimposed on the wall geometry illustrates the finite-element substructure in the mathematical model. (Reproduced from Janz and Waldron Predicted effect of chronic apical aneurysms on the passive stiffness of the human left ventricle, Circ Res 42 255,1978 with permission from the American Heart Association.)... Figure 10. Undeformed shape of the free wall of a normal rat left ventricle. The network superimposed on the wall geometry illustrates the finite-element substructure in the mathematical model. (Reproduced from Janz and Waldron Predicted effect of chronic apical aneurysms on the passive stiffness of the human left ventricle, Circ Res 42 255,1978 with permission from the American Heart Association.)...
In Figure 12 (left panel), the predicted free wall geometry of the human LV with an apical transmural fibrous-muscular aneurysm encompassing approximately 10% of the wall volume, is displayed. The right panel shows the predicted... [Pg.48]

A number of researchers have measured descending cluster velocities in the wall layer for a variety of flow conditions and different wall geometries, with most data between 0.5 and 2.0 m/s. The data have been well summarized by Griflith and Louge (1998) and are correlated by equation (22). [Pg.523]

Golriz MR. Influence of wall geometry on temperature distribution and heat transfer in circulating fluidized bed boilers. In Avidan AA, ed. Circulating Fluidized Bed Technology IV. New York AIChE, 1994, pp 693-700. [Pg.540]

A telltale sign of ICEP is the presence of non-uniform ICEO flow around the particle, which leads to complex hydrodynamic interactions with other particles and walls. For example, the basic quadrupolar flow in Fig. la causes two symmetric particles to move toward each other along the field axis and then push apart in the normal direction [13, 15]. A finite cloud of such particles would thus become squashed into a disk-like spreading pancake perpendicular to the field axis [3]. The same flow field can also cause particles to be repelled from insulating walls (perpendicular to the field) [16] or attracted toward electrodes (normal to the field), but these are only guiding principles. Broken symmetries in particle shape or wall geometry, however, can cause different motion due to combined effects of DEP and ICEP, even opposite to these principles, and the interactions of multiple particles can also be influenced strongly by walls. Such effects have not yet been fully explored in experiments or simulations. [Pg.527]

The improvement of heat transfer by optimized channel and wall geometries and the choice of best-suited materials contribute to the enhancement of process speed and to a better control of selectivity. Adapted selectivity can be achieved by realizing well-defined temperature proto-... [Pg.1624]

For testing different mean-field models developed in this work we use a simple wall geometry wherein electrolyte is confined to a half-space x > 0 by a charged wall with a surface charge a. This reduces all the equations to ID and the standard PB equation reads. [Pg.214]

For the wall geometry and symmetric 1 1 electrolyte the dipolar PB equation becomes. [Pg.218]

In Fig. 1 we plot the results of the dipolar PB equation for the wall geometry. The dielectric constant is no longer uniform but grows in the wall vicinity. Increased electrostatic screening reflects the excess of solvent molecules near a wall on account of dielectrophoresis (a transport of dipoles in nonuniform field). The saturation effect of the Langevin function is, therefore, not dominant. As a consequence of increased screening near a wall, the counterions are depleted from the wall region. [Pg.219]


See other pages where Wall geometries is mentioned: [Pg.35]    [Pg.631]    [Pg.35]    [Pg.330]    [Pg.51]    [Pg.497]    [Pg.294]    [Pg.221]    [Pg.576]    [Pg.834]    [Pg.2691]    [Pg.138]    [Pg.108]    [Pg.478]    [Pg.733]    [Pg.178]    [Pg.321]    [Pg.182]    [Pg.188]    [Pg.189]   


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