Curvature effect

Kofman R ef a/1989 Solid-liquid transition of metallic clusters occurrence of surface melting Physica A 157 631 Kofman R ef al 1994 Surface melting enhanced by curvature effects Surf. Sc/. 303 231... 

The experimental data are predicted well by the ASM and RSM models but the k-Z model fails to account for most of the curvature effects. 

Cavitation. The subject of cavitation in pumps is of great importance. When the Hquid static pressure is reduced below its vapor pressure, vaporization takes place. This may happen because (/) the main stream fluid velocity is too high, so that static pressure becomes lower than vapor pressure (2) localized velocity increases and static pressure drops on account of vane curvature effect, especially near the inlets (J) pressure drops across the valve or is reduced by friction in front of the pump or (4) temperature increases, giving a corresponding vapor pressure increase. 

The previous analysis of the electronic structure of the carbon nanotubes assumed that we could neglect curvature effects, treating the nanotube as a single... 

When a droplet reaches the peak of its appropriate curve, due to being in a region of RH greater than the RH for that critical size, it will continue to grow in an uncontrolled fashion. As it gets larger, the curvature effect decreases its vapor pressure and it enters a region of increased supersaturation relative to that at the peak of the Kohler curve. A particle that turns into a droplet and passes the critical size is said to be an activated CCN. 

V. Nayagam and F. A. Williams, Curvature effects on edge-flame propagation in the premixed-flame regime, Combust. Sci. Tech. 176 2125-2142,2004. 

Stuart SJ, Berne BJ (1999) Surface Curvature Effects in the Aqueous Ionic Solvation of the Chloride Ion. J Phys Chem A 103(49) 10300-10307... 

SPT provides a conceptual basis relating the nonpolar free energy contribution to the solvent-exposed surface area. An attractive approximation is to ignore curvature effects and write... 

Because surface curvature depends on radius and different atoms have different sizes, and because the atomic surface tension depends on atomic number, the atomic surface tensions also include surface curvature effects, which has recently been studied as a separate effect.7 Local surface curvature may also correlate with nearest-neighbor proximity and thus may be implicitly included to some extent when semiempirical atomic surface tensions depend on interatomic distances in the solute. 

The curvature effect of the double helix of DNA, caused by the binding of dimers of active receptors to the HRE sequences, has been obtained by means of experiments of transfection of lineal DNA structures to cells that previously did not express the gene under study. The reality of the cells in vivo must be... 

The first point to be made is that the structure of the bilayers changes due to an imposed curvature. These curvature effects are easily monitored in an SCF analysis. Unless one is willing to do a three-dimensional analysis, the method is restricted to homogeneously curved bilayers, i.e. cylindrical or spherically shaped vesicles. 

Given the thinness of a diffusion flamelet, it is possible to neglect as a first approximation curvature effects, and to establish a local coordinate system centered at the reaction interface. By definition, X is chosen to be normal to the reaction surface. Furthermore, because the reaction zone is thin compared with the Kolmogorov scale, gradients with respect to X2 and X3 will be much smaller than gradients in the x direction (i.e., the curvature is small).112 Thus, as shown in Fig. 5.18, the scalar fields will be locally onedimensional. 

For moderately doped substrates, when the surface is free of oxide the change of potential is mostly dropped in the space charge layer and in the Helmholtz double layer. The reactions are very sensitive to geometric factors. The reaction that is kinetically limited by the processes in the space charge layer is sensitive to radius of curvature, while that limited by the processes in the Helmholtz layer is sensitive to the orientation of the surface. Depending on the relative effect of each layer the curvature effect versus anisotropic effect can vary. 

Using this graph and the relationship it contains, one can now address the question of whether and under what conditions a laminar flame can exist in a turbulent flow. As before, if allowance is made for flame front curvature effects, a laminar flame can be considered stable to a disturbance of sufficiently short wavelength however, intense shear can lead to extinction. From solutions of the laminar flame equations in an imposed shear flow, Klimov [50] and Williams [51] showed that a conventional propagating flame may exist... 

Two-level factorial designs are useful for estimating first-order factor effects and interaction effects between factors, but they cannot be used to estimate additional second-order curvature effects such as those represented by the terms P, and P22 -in the model... 

Up to now we discussed planar grafting layers. It is of much interest to consider the case where polymers are grafted to curved surfaces. The first study taking into account curvature effects of stretched and tethered poly-... 

Green 8c E. James Jr, "Radius of Curvature Effect on Detonation Velocity , 4th-ONRSympDeton (1965), pp 86-91 (The effect of the radius of curvature of the detonation front on the detonation velocity of certain explosives were measured. The results were used to calculate the reaction zone thicknesses for various expls. For example, such thickness was found as 0.064 mm for 85/15-HMX/Viton, using Holston HMX, whereas for the same type plastic-bonded expl made from British Bridgwater HMX it was 0.182mm) 28) C.G. Dunkle, private... 

The classic extrusion model gives insight into the screw extrusion mechanism and first-order estimates. For more accurate design equations, it is necessary to eliminate a long series of simplifying assumptions. These, in the order of significance are (a) the shear rate-dependent non-Newtonian viscosity (b) nonisothermal effects from both conduction and viscous dissipation and (c) geometrical factors such as curvature effects. Each of these... 

M. L. Hami and J. F. T. Pittman, Finite Element Solutions for Flow in a Single-Screw Extruder, Including Curvature Effects , Polym. Eng. Sci., 20, 339 (1980). 

Moreover, flight clearance and curvature effects were also accounted for. Figure 9.37 indicates that, in this particular case, the simple Newtonian model provides a reasonable estimate, although it overestimates the rate of melting. Note that the predicted curve should approach the closed circles and triangles, which are the measured solid bed width at the melt film, rather than the open circles and triangles, which are the corresponding values at the root of the screw. As observed experimentally, the width near the root of the screw is reduced as a result of melt pool circulation. 

Modihcations of this model, including a nonlinear temperature prohle in the melt him, channel curvature effects, and an approximate method to account for the flight clearance effect, are presented by Tadmor and Klein (1), together with expressions for power calculations. Numerous other improvements of the melting model have been suggested in the literature (33,41 -6). A detailed discussion of these, however, is beyond the scope of this text. 

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