Influence of Specific Surface

The influence of the specific surface of the primary explosives on their initiation efficiency has already been included in the graphs above as reflected by their compaction behavior. It was further studied in a standard detonator number 3 cap with 0.35 g of TNT compressed by 76.5 MPa as a secondary charge [9]. LA was compressed by 13.8 MPa without any reinforcing cap while MF and DDNP were compressed by the same pressure with a reinforcing cap. The results are shown in Fig. 2.10. Both DDNP and LA show a performance relatively independent of speciflc surface with the best performance around 4,000 cm g The behavior of MF is however quite different, as its minimal necessary amount continually increases with increasing specific surface (decreasing crystal size). 

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Charbeneau, G. T. (1961). Influence of specific surface on some properties of silicate cement. Journal of Dental Research, 40, 763. 

Svetlov (Ref 2) described modern Russ nonpermissible expls, which.included Igdanit Usachev (Ref 3) studied the influence of specific surfaces of AN in Igdanit on their expl props. Sp surfaces were caicd by the formula developed by Usachev... 

Sasaki K. et al. (1993) Highly reactive y -dicalcium silicate. V. Influence of specific surface area on hydration. Journal of the American Ceramic Society 76,970-974. 

Influence of specific surface area on dissolution rate of alumina... 

Another largely unexplored area is the change of dynamics due to the influence of the surface. The dynamic behavior of a latex suspension as a model system for Brownian particles is determined by photon correlation spectroscopy in evanescent wave geometry [130] and reported to differ strongly from the bulk. Little information is available on surface motion and relaxation phenomena of polymers [10, 131]. The softening at the surface of polymer thin films is measured by a mechanical nano-indentation technique [132], where the applied force and the path during the penetration of a thin needle into the surface is carefully determined. Thus the structure, conformation and dynamics of polymer molecules at the free surface is still very much unexplored and only few specific examples have been reported in the literature. 

The solution phase is modeled explicitly by the sequential addition of solution molecules in order to completely fill the vacuum region that separates repeated metal slabs (Fig. 4.2a) up to the known density of the solution. The inclusion of explicit solvent molecules allow us to directly follow the influence of specific intermolecular interactions (e.g., hydrogen bonding in aqueous systems or electron polarization of the metal surface) that influence the binding energies of different intermediates and the reaction energies and activation barriers for specific elementary steps. 

The effects of calcium on polymer-solvent and polymer-surface interactions are dependent on polymer ionicity a maximum intrinsic viscosity and a minimum adsorption density as a function of polymer ionicity are obtained. For xanthan, on the other hand, no influence of specific polymer-calcium interaction is detected either on solution or on adsorption properties, and the increase in adsorption due to calcium addition is mainly due to reduction in electrostatic repulsion. The maximum adsorption density of xanthan is also found to be independent of the nature of the adsorbent surface, and the value is close to that calculated for a closely-packed monolayer of aligned molecules. 

The range of specific surface area can vary widely depending upon the particle s size and shape and also the porosity.t The influence of pores can often overwhelm the size and external shape factors. For example, a powder consisting of spherical particles exhibits a total surface area, S, as described by equation (1.6) ... 

Earlier investigations presented in the papers [4,14] suggest a higher selectivity of adsorption in respect to preferentially adsorbed component for adsorbents containing narrower mesopores. Similar effect should be expected for microporous materials In order to study the influence of porosity type on adsorption from liquids the measurements of specific surface excess isotherms were performed for binary liquid mixtures benzene + n-heptane / carbon AC-2 and AC-4 benzene + 2-propanol / carbon AC-2 and AC-4. 

In this paper we present results related to the atomic structure and catalytic properties of Pd overlayers on various substrates. A reaction has been chosen to test the catalytic properties of these systems, it is the 1,3-butadiene hydrogenation, a reaction for which Pd is known to be the best catalyst. In the following, after a short description of the experimental approach, the 1,3-butadiene hydrogenation reaction and the specific properties of Pd for this reaction will be presented. Then the reactivity of several Pd overlayers obtained either by surface segregation in Pd-based alloys or by atomic beam deposition on a metal will be investigated and discussed in terms of structure, composition related to surface segregation and surface stress. The influence of the surface orientation of the substrate will be discussed. 

The surface roughness of filled materials is obviously not related to filler surface imperfections but it is very much determined by the shape of filler particles.The effect of glass fibers in plastics and flatting agents are specific examples of the influence of specific shaped particles on surface roughness. 

Grafting has been used for the preparation of vanadia on titania catalysts [24]. Vanadyl triisobutoxide was used as precursor. The vanadia species were well dispersed. It was observed by electron microscopy that silica was present as an amorphous phase. Moreover, the amount of titania present in the catalysts influences the specific surface area and the pore volume. Lower titania concentrations give rise to both higher specific surface areas and pore volumes. The most stable catalyst contained equimolar titania-silica or pure titania. 

The influence of specific proteins in the complex mixture in the adsorbed layer on cellular reactions has yet to be demonstrated directly, but purified proteins preadsorbed to surfaces and then exposed to blood provide information on the potential of various proteins to influence cellular events. A much more comprehensive study of this type which includes proteins such as von Willebrand factor and a2-macroglobulin is presented in this volume (63). The ability of proteins to enhance or repress cellular reactions when used as pure preadsorbates does not indicate the magnitude of the role played by the protein when present in the complex layer adsorbed from plasma. The protein may be present in very small amounts in the plasma-derived adsorbate relative to the purified preadsorbed layer. For example, von Willebrand factor is present at very low concentrations in plasma (10-15 xg/mL) and is therefore probably present at very low levels in the absorbed layer formed on polymers exposed to plasma. Thus, although von Willebrand factor undoubtedly could be an important factor in surface thrombosis, its influence at the very low adsorption levels likely to exist in vivo must be demonstrated. However, the knowledge of which proteins are potentially important, derived from preadsorption studies, is extremely useful in focusing attention on specific proteins to study in the actual adsorbed layer. 

The most cost-efficient way to improve operational characteristics is to modify the existing polymeric matrixes therefore, currently the group of polymeric materials modified with NS is of special interest. The NS are able to influence the supermolecular stmcture, stimulate self-organization processes in polymeric matrixes in supersmall quantities, and thus contributing to the efficient formation of a new phase medium modified - nanocomposite and qualitative improvement of the characteristics of final product - PCM. This effect is especially visible when NS activity increases which directly depends on the size of specific surface, shape of the particle, and its ultimate composition [22]. Metal ions in the NS used in this work also contribute to the activity increase as they stimulate the formation of new bonds. 

The dependence of Cu/C nanocomposite influence on PEPA viscosity in the concentration range 0.001-0.03% was found. The growth of specific surface of NC particles contributes to partial decrease in PEPA kinematic viscosity at concentrations 0.001% and 0.01% with its further elevation at the concentration 0.03%. The IR investigation of Cu/C nanocomposite FS confirms the quantum-chemical computational experiment regarding the availability of NC interactions with PEPA amine groups. The intensity of these groups increased several times when Cu/C nanocomposite was introduced. 

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