Disperse particles, deposition

Polystyrene latex particles were coagulated by the addition of Ba(N03)2. The number of dispersed particles deposited onto a planar polystyrene surface was determined 15 min after the addition of salt by optical microscopy. The light microscope does not permit the aggregation of the deposited particles to be determined subsequent examination by the electron microscope gives this information. Clint et al. obtained the following results ... 

Water column model. A comprehensive chemical mass balance in the water column should account for mass change with time, advection and dispersion, particle deposition, soluble release, particle resuspension from the bed, evaporation to air and degradation. Over a differential distance x in the direction of flow (L) these processes are. 

In another study of the physical behavior of soap-LSDA blends, Weil and Linfield [35] showed that the mechanism of action of such mixtures is based on a close association between the two components. In deionized water this association is mixed micellar. Surface tension curves confirm the presence of mixed micelles in deionized water and show a combination of optimum surface active properties, such as low CMC, high surface concentration, and low surface concentration above the CMC. Solubilization of high Krafft point soap by an LSDA and of a difficulty soluble LSDA by soap are related results of this association. Analysis of dispersions of soap-LSDA mixtures in hard water shows that the dispersed particles are mixtures of soap and LSDA in the same proportion as they were originally added. These findings are inconsistent with the view that soap reacts separately with hard water ions and that the resulting lime soap is suspended by surface adsorption of LSDA. The suspended particles are responsible for surface-active properties and detergency and do not permit deposits on washed fabric unlike those found after washing with soap alone. 

EXPLOSION Finely dispersed particles form explosive mixtures in air. Prevent deposition of dust closed system, dust explosion-proof electrical equipment and lighting. Prevent build-up of electrostatic charges (e.g., by grounding). ... 

Drug delivery to the respiratory tract has been characterized in the past decade by an increase in knowledge of drug droplet or particle manufacture, behavior, aerosol dispersion, lung deposition and clearance. The number of diseases for which aerosol therapy may be applicable has increased dramatically. The pharmaceutical scientist is no longer limited to pulmonary diseases as therapeutic targets. Substantial progress has been made in every area of pharmaceutical aerosol science, and it is anticipated that this will ultimately lead to many new therapies. 

Scale deposits are converted to dispersed particles which can be circulated out of the wellbore. A chelating agent such as ethylenediamine tetraacetic acid can aid in dissolving calcium sulfate deposits. Hydrochloric acid following the basic treatment can also be used to dissolve calcium sulfate (167). 

The method of thermal vacuum deposition has been used to obtain tin and silicon deposit on TEG surface. The main difficulty at metal component deposition on graphite support is to obtain uniform metal coating on the surface of disperse particles. The system of uninterrupted mixing of TEG powder during the material evaporation has been created. Its principle... 

Disadvantages Upon delivery, coughing and other unpleasant sensations may be induced as the carrier particles deposit in the mouth and throat A larger amount of powder needs to be moved and dispersed in terms of energy requirements, the gains in dispersion may be offset by the increase in payload... 

A different approach which also starts from the characteristics of the emissions is able to deal with some of these difficulties. Aerosol properties can be described by means of distribution functions with respect to particle size and chemical composition. The distribution functions change with time and space as a result of various atmospheric processes, and the dynamics of the aerosol can be described mathematically by certain equations which take into account particle growth, coagulation and sedimentation (1, Chap. 10). These equations can be solved if the wind field, particle deposition velocity and rates of gas-to-particle conversion are known, to predict the properties of the aerosol downwind from emission sources. This approach is known as dispersion modeling. 

Conventional routes to ceramics involve precipitation from solution, drying, size reduction by milling, and fusion. The availability of well-defined mono-dispersed particles in desired sizes is an essential requirement for the formation of advanced ceramics. The relationship between the density of ceramic materials and the sizes and packing of their parent particles has been examined theoretically and modeled experimentally [810]. Colloid and surface chemical methodologies have been developed for the reproducible formation of ceramic particles [809-812]. These methodologies have included (i) controlled precipitation from homogeneous solutions (ii) phase transformation (iii) evaporative deposition and decomposition and (iv) plasma- and laser-induced reactions. 

Various studies and some patents have been published on the use of membrane catalysts for the direct synthesis of H202 [73-81]. The redox treatment of the membrane influences the properties both in the synthesis and decomposition of H202. Formation of a hydrophobic layer improves the selectivity, because it limits the consecutive decomposition of hydrogen peroxide, limiting the chemisorption of H2 and re-adsorption of H202 [73]. Either polymeric or ceramic-type membranes could be used, but the latter are preferable to allow more robust operations. The mono- or bi-metallic Pd-based active component could be deposited either in the form of dispersed particles (e.g., by precipitation-deposition) or of a thin film (e.g., by... 

An important step towards treatment of SO2 conversion to sulfate and deposition of both species that avoids absolute uncertainties of dispersion and deposition rates was taken by Lewis and Stevens, who investigated the mathematical basis of one form of hybrid receptor modeling (.16). Their model assumes that one measures concentrations of SO2 and SO4 relative to that of some species borne by particles from the plant. They assumed that (1) dispersion, deposition and transformation of the three species (SO2, SO4 and fine primary particles) are linear or pseudo first-order processes, but may have complex dependences on time (2) dispersion affects all three pollutants identically (3) dry deposition is the only type of deposition which occurs (4) deposition velocity is the same for all fine particles, but may be different for SO2 (5) secondary sulfate is produced only by homogeneous oxidation of SO2. 

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