Geometries, from various experimental

Good consistency of the parameters derived from various experimental data is observed for rigid materials with regular pore geometry and sharp boundary between solid surface and pore space. The contrast between empty pores and silica is large both for X-rays and positrons. However, in the case of chemically modified silica this interface boundary is characterized by the presence of transition layer for which the structure and density is not satisfactory established. Thus, pore dimensions determined by using different techniques exhibit some discrepancy. 

They compared the PME method with equivalent simulations based on a 9 A residue-based cutoflF and found that for PME the averaged RMS deviations of the nonhydrogen atoms from the X-ray structure were considerably smaller than in the non-PME case. Also, the atomic fluctuations calculated from the PME dynamics simulation were in close agreement with those derived from the crystallographic temperature factors. In the case of DNA, which is highly charged, the application of PME electrostatics leads to more stable dynamics trajectories with geometries closer to experimental data [30]. A theoretical and numerical comparison of various particle mesh routines has been published by Desemo and Holm [31]. 

The parameters in the original parameterization are adjusted in order to reproduce the correct results. These results are generally molecular geometries and energy differences. They may be obtained from various types of experimental results or ah initio calculations. The sources of these correct results can also be a source of error. Ah initio results are only correct to some degree of accuracy. Likewise, crystal structures are influenced by crystal-packing forces. 

We used DFT to optimize the geometries of various Hammett bases on cluster models of zeolite Brpnsted sites. For p-fluoronitrobenzene and p-nitrotoluene, two indicators with strengths of ca. -12 for their conjugate acids, we saw no protonation in the energy minimized structures. Similar calculations using the much more strongly basic aniline andogs of these molecules demonstrated proton transfer from the zeolite cluster to the base. We carried out F and experimental NMR studies of these same Hammett indicators adsorbed into zeolites HY and HZSM-5. 

Electron diffraction provides experimental diffraction spectra for comparison with computed spectra obtained from various intuitive geometrical models, but this technique alone is generally insufficient to locate the hydrogen atoms. A quantum approach, on the other hand, indicates the positions of the H atoms, which can then be introduced into the calculation of the theoretical spectra in order to complete the determination of the geometry. 

We have to conclude from our experimental observations that the carbon black has a direct dependence upon the molecular structure of the feedstock. This dependence is fairly broad in that, as long as the feedstock is predominately aromatic, other variables of reactor geometry, rates and ratios of feed materials, and temperature can be adjusted to produce various grades of carbon black. Commercial production of carbon blacks have added incentive of optimizing the economic variables of efficiency, yield, and throughput. 

The comparison of the structures of free and crystalline molecules has been based predominantly on the application of various experimental techniques, but theoretical calculations play an ever increasing role. Thus, it is important to comment upon the inherent differences in the physical meaning of the structural information originating from such different sources [114], The consequences of intramolecular vibrations on the geometry of free molecules have already been... 

A particle starting from the base of the bed first accelerates from rest to a peak velocity, and then decelerates until it again reaches zero velocity at the top of the spout, where it reverses its direction of movement. In addition, a radial profile of longitudinal velocity exists at a particular level, the velocity at the axis of the spout being higher than at other radial positions. Velocity profiles, both in the vertical and the radial directions, have been measured by several investigators, with various solid materials and bed geometries. Two different experimental techniques have been used visual observation and particle-impact measurement. 

Measure the specimen compliance C for various values of crack length a, for a given specimen geometry, from the EOAD versus LOAD-POINT DISPLACEMENT curves. Note that this may be done experimentally or numerically from a finite-element analysis. 

Smith et al. showed (albeit without correction for the gas phase flow pattern) that kio data from various scales (7=0.4 to 1.8 m), geometries (T/D = 2 to 3, ///7 = 1), and agitator types (6,12,18 flat-blade, 6-concave-blade, 6-perforated blade disc turbines) could all be correlated by an equation of the form of equation (15.16), so equation (15.16) may apply to other scales and configurations, though this has yet to be demonstrated experimentally. A more recent review , however, presents different values for the index Y for coalescing and non-coalescing systems. It should be borne in mind that this was based on earlier data without correction for the effect of gas flow pattern. 

Comparison of experimental derived curves of distribution by reagents residence times with curves calculated from (1.9) and (1.11) allows to receive numerical values of Bo h n and consequently to estimate degree of deviation of flows structures in reaction zone of various geometry from idealized models. 

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