Particle size surfaces

Carlson, The Effect of Particle Size-Surface Area and Oxygen on the Hydrogen Content of Titanium Hydrides , Ref 160, p 616. See also related paper on p 50 of Ref 160 124) F.W. 

Various finishes can be achieved — gloss, satin (or egg-shell) or matt. This is accomplished by the addition of particles of size 1-5 pm of, for example, silica, china clay or the white pigment, TiCK The degree of mattness depends on various factors, such as particle size, surface treatment of the particles, rate of film formation, and the polymer composition, e.g., urethane/acrylate compared with epoxy/acrylate. The former requires smaller particles larger particles cannot be used as they create a rough surface. 

Particles may be trapped on the biofilm surface or in voids of the biofilm where any organics may be hydrolyzed and further take part in the transformation processes. A number of factors influence adsorption and desorption of particles, such as particle size, surface charge, pH, etc., as well as biofilm surface properties and bulk water flow pattern. Studies of model biofilms have shown that water flows into the biofilm in small channels, making the prediction of transport of particles as well as soluble compounds complex (Norsker et al., 1995). 

Mean particle size Surface area Specific pore volume Dispersion (pm) (m /g) (ml/g) (%)... 

The viscoelastic properties of polypropylene melts containing magnesium hydroxide fire retardant fillers have been studied using parallel plate dynamic rheology [36]. In this work the filler variants differed in particle size, surface area and morphology, ranging from approximately spherical particles formed... 

The relative solubilities reported are very crude estimates based on equilibrium solubility products. These estimates do not take into account variations in solubility as a function of pH, ionic strength, activities of various solution species (e.g., HCO "), redox state, particle size, surface defect types and concentrations, the concentration of various types of adsorbates, including natural organic matter, on mineral surface, or the presence of different types of bacteria or microbial biofilms on mineral surfaces. 

Both stereoisomers were formed, implying a loss of stereochemical integrity during the formation of the second carbon-carbon bond. When the reaction was conducted on ZnO, surface-related processes affected both the rate and stereochemistry. The effect of various quenchers could be explained as competitive adsorption at active sites, with or without interference with electron transfer. A reaction scheme involving formation of dimer, both in the adsorbed state and in solution, was proposed, the former route being the more important On CdS, the reaction could sometimes be induced in the dark as well because of the presence of acceptor-iike surface states. Neither particle size, surface area, nor crystal structure appeared to significantly influence the dimerization observations parallel to those found in the CdS photoinduced dimerization of N-vinylcarbazole... 

Variation in raw materials is one of the major causes of product variation or deviation from specification. The API may represent the most uncontrollable component in the complete product/process validation scheme, as key physical properties such as morphology and particle size/surface area may not be completely defined this early in the sequence. Often times the synthesis of the new API (drug substance) is not finalized, and changes occur during the development of the compound. 

Apart from particle size, surface properties of particulates also have been considered to affect uptake by the intestinal epithelia. Although... 

Magnesium stearate, steatric acid, Lubricant Particle size, surface area... 

There are several different ways of producing these fillers resulting in various forms differing in particle size, surface area, purity, and morphology, which can have a profound influence on their performance as fire retardants. An overview of their principal methods of production is considered in the following text. 

Grade of sihca used (particle size, surface area, density, surface chemistry, etc.)... 

Basically all process parameters, some of which are fixed and some of which are variable, influence the quality of the final product of the precipitation. Usually precipitates with specific properties are desired. These properties could be the nature of the phase formed, chemical composition, purity, particle size, surface area, pore sizes, pore volumes, separability from the mother liquor, and many more, including the demands which arc imposed by the requirements of downstream processes, like drying, pelletizing, or calcination. It is therefore necessary to optimize the parameters in order... 

The principal materials being fed into the reactor are air, gas (or fuel), and the feedstock. The materials coming out of the reactor are, of course, combustion gases, carbon black, water, and the nitrogen which comes into the reactor in the air and passes through unchanged. The question we have then is how is the feedstock converted to carbon black What are the reactions that occur, where do they occur, and under what variables, what are the reactor rates, and what are the mechanisms of carbon black formation What are the key variables in the system relative to controlling particle size, surface area, and structure ... 

Because of low solubility of the compound in pure water, for the oral administration a suspension in an aqueous solution of hydroxyethylcellulose (0.5 %) was used. The solid state physical parameters (particle size, surface area, amorphicity and crystal modification) and the suspension properties (agglomeration tendency, homogenicity and dissolved part of the drug) had to be investigated. For the intravenous administration, an aqueous solution containing saline, DMSO and PEG 400 was used as formulation. 

After biomass removal has been achieved if appropriate, the main objective of the primary recovery stages is to isolate the product from significant impurities which will generally be in the same phase. At this stage of bioseparation, it is necessary to exploit some difference between the product and impurities such as solubility (in water or an organic solvent), particle size, surface affinity, charge and so on. 

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