Solid-liquid mixing objectives

The attractiveness of the network-of-zone method to compute solid-liquid mixing flows resides in its relative simplicity while being capable of capturing the main flow phenomena for a wide range of concentrations. The objective of the present work is to assess the real capability of this approach in the case of a complex mixing problem involving a coaxial mixer. Coaxial mixers are very popular for the preparation of pastes and slurries in the chemical, food, and coating industries. Another mixer setup is also tested. 

The primary objectives of solid-liquid mixing are to create and maintain a slurry and/or to promote and enhance the rate of mass transfer between the solid and liquid phases. The mixing operation promotes the... 

Determination of the maximum particle concentration is also of interest since it no longer constitutes a purely kinematical problem. Rather, the suspension contained within the unit cell is now a mixed object possessing both solid-like and liquid-like features. In particular, it behaves like a solid insofar as mutual impenetrability demands are concerned, whereas it behaves like a liquid in its ability to change its configuration (i.e., it can flow ). 

The duties to be achieved in processing these highly viscous materials include blending and/or the incorporation of fine solids. In blending operations two or more materials, often having widely differing viscosities and volume ratios, have to be mixed to yield a product of desired uniformity or mixture quality. For the dispersion of Fine solids into viscous liquids the objective is to produce a final mix with an acceptably low level of agglomerates of the basic individual particles. 

Suspended solids are often the process objective that requires a specific degree of uniformity. Five guides to better liquid/solid mixing are ... 

Convection involves the transfer of heat by means of a fluid, including gases and liquids. Typically, convection describes heat transfer from a solid surface to an adjacent fluid, but it can also describe the bulk movement of fluid and the associate transport of heat energy, as in the case of a hot, rising gas. Recall that there are two general types of convection forced convection and natural (free) convection. In the former, fluid is forced past an object by mechanical means, such as a pump or a fan, whereas the latter describes the free motion of fluid elements due primarily to density differences. It is common for both types of convection to occur simultaneously in what is termed mixed convection. In such instance, a modified form of Fourier s Law is applied, called Newton s Law of Cooling, where the thermal conductivity is replaced with what is called the heat transfer coefficient, h ... 

The fact that the structure of a solid monomer influences its polymerization substantially now seems obvious. It is not as clear whether structural phenomena can effect polymerization if the monomer is a liquid. It has long been known that ordered regions or clusters exist in liquids, and several years ago it was assumed that in some cases these regions in liquid monomers can influence the polymerization. One of the most vivid examples—namely, polymerization in the liquid-crystalline state—was accomplished by Krentzel and co-workers (I, 2, 3). The object of their study was p-methacrylylhydroxybenzoic acid, which forms conventional crystals in the pure state and does not polymerize in the solid state. However, when mixed with alkoxybenzoic acid, it forms liquid crystals of both smectic and nematic forms. Polymerization of p-meth-acryllylhydroxybenzoic acid in various forms of liquid crystals was compared with polymerization of the same substance dissolved in dioxane and dimethylformamide (DMF). 

Since the object of interest is dropped into the calorimeter, this type of calorimeter is often referred to as a Drop Calorimeter. Since the object of interest exchanges heat by mixing with the calorimeter object (liquid or solid) the technique is referred to as the Mixture... 

Next we shall describe some of the objectives used in sample pre-treatment. The objective of these procedures is to reduce the volume of the samples. Portioning, evaporation concentration, chemical separation, absorption and so forth are techniques used alone or in an appropriate combination for liquid samples. Drying, sieving, pulverisation, mixing, reduction, ashing and so forth are techniques used alone or in an appropriate combination, for preparing samples of solids for measurement. 

Explosives are solid or liquid ) substances, alone or mixed with one another, which are in a metastable state and are capable, for this reason, of undergoing a rapid chemical reaction without the participation of external reactants such as atmospheric oxygen. The reaction can be initiated by mechanical means (impact, -> Impact Sensitivity friction, -> Friction Sensitivity), by the action of heat (sparks, open flame, red-hot or white-hot objects), or by detonating shock (-> Blasting Cap with or without a - Booster charge). The resistance of the metastable state to heat is known as - Stability. The ease with which the chemical reaction can be initiated is known as -> Sensitivity. 

Discussion In addition to the obvious occurrence of water in the liquid form and in the solid form, as ice and snow, water is present in many materials Avhich on casual examination seem to be dry. In these cases the water is so intimately mixed with the other substances present that it must be separated from them before it can be recognized. Often pressure alone is sufficient to do this, that is water can be squeezed out of apparently dry objects but in other instances the object must be heated so as first to vaporize the water, which later condenses, before its presence can be detected. There is danger, however, of being misled in these latter cases, for heating may have produced water by chemical changes in the substances of which the material is composed, instead of merely separating water which already existed as a constituent of a mixture. 

The density of the mixed solution should be based on the percentage of each liquid and its density. Because the solid object is suspended in the mixed solution, it should have the same density as this solution. The density of the mixed solution is ... 

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