Dispersion of solids

The more common requirement to control routine disposal and dispersion of solid, liquid or gaseous pollutants is based upon different criteria, e.g. their persistence in the environment (as with the effects attributed to ozone-depleting gases, or the problem of heavy metal contamination... 

For preparing lakes, a solution of aluminium sulfate (or chloride) is mixed with sodium carbonate, forming fresh alumina Al(OH)3. The colorant is then added and adsorbed on the surface of alumina. Usually the content of colorant in the lake ranges from 10 to 40%." The product is filtered, washed with water, dried, and milled. The product is allowed to contain unreacted alumina but must not contain more than 0.5% HCl-insoluble matter and not more than 0.2 % ether-extractable matter. - Lakes are insoluble in most solvents used for pure dyes, and they have high opacity and better stability to light and heat. Lakes impart their color by dispersion of solid particles in the food. The coloring properties of lakes depend on particles, crystal structures, concentrations of dye, etc. 

In terms of the two-phase system which comprises dispersions of solids in liquids, the minimum energy requirement is met if the total interfacial energy of the system has been minimized. If this requirement has been met, chemically, the fine state of subdivision is the most stable state, and the dispersion will thus avoid changing physically with time, except for the tendency to settle manifest by all dispersions whose phases have different densities. A suspension can be stable and yet undergo sedimentation, if a true equilibrium exists at the solid-liquid interface. If sedimentation were to be cited as evidence of instability, no dispersion would fit the requirements except by accident—e.g., if densities of the phases were identical, or if the dispersed particles were sufficiently small to be buoyed up by Brownian movement. 

Description Homogeneous dispersion of solid drug in a polymer mix... 

Large-scale ultrasonic irradiation is extant technology. Liquid processing rates of 200 liters/minute are routinely accessible from a variety of modular, in-line designs with acoustic power of several kW per unit (83). The industrial uses of these units include (1) degassing of liquids, (2) dispersion of solids into liquids, (3) emulsification of immiscible liquids, and (4) large-scale cell disruption (74). While these units are of limited use for most laboratory research, they are of potential importance in eventual industrial application of sonochemical reactions. 

Because of the requirements of insolubility in water, in organic solvents and in the medium that it is being used to colour, the application processes for using pigments are quite different from those for dyes. Coloration with pigments is essentially a process of dispersion of solid particles of the pigment in a semi-solid medium. 

Batch equilibrium tests are conducted on solid phase suspensions, prepared with previously air-dried solids, ground to uniform powdery texture for mixing with various concentrations of the pollutants of interest in solution. The concentrations of these pollutants or the COMs leachate in the solution are designed to evaluate the capability of the suspended solids to adsorb all the pollutants possible with increasing amounts of available pollutants, consistent with interaction characteristics dictated by the surface properties of the solids and the pollutants [1,16,22-26,66,67,71]. For a successful and proper study of solid particle sorption of pollutants, the requirement for complete dispersion of solid particles in solution is absolute [143 -145]. Common practice is to use a solution to solid ratio of 10 1 [1], together with efficient sample agitation at a constant temperature (e.g.,48 h at 20 °C). 

The first wave-dispersion-type screw was developed and patented by Kruder in 1975 [18], and the device was trademarked as the Wave screw. Numerous other wave dispersion screws were developed later based on Kruder s design. The term wave dispersion screw refers to screws with metering sections that have two or more channels with a flight between them that is selectively undercut to allow the dispersion of solid polymer fragments and molten resin. Several commercially available screws utilize this type of technology and are discussed in this section. These screws include Double Wave screws, Energy Transfer screws. Variable Barrier Energy Transfer screws, DM2 screws, and Fusion screws. 

Two basic processes are used to create smoke clouds the condensation of vaporized material and the dispersion of solid or liquid particles. Materials can either be released slowly via a pyrotechnic reaction or they can instantaneously be scattered using an explosive material. Technically, a dispersion of fine solid particles in air is termed a smoke, while liquid particles in air create a fog. A smoke is created by particles in the 10 -10 " meter range, while larger suspended particles create a dust (1). ... 

Colloid chemistry investigates substance mixtures. These substance mixtures can be heterogenous, such as emulsions (in which tiny droplets of one liquid are dispersed in another), suspensions (consisting of a fine dispersion of solid particles in a liquid volume phase), and aerosols (in which liquid droplets are dispersed in the gas phase). However, there are also homogenous mixtures in which the solute is present in larger, supermolecular aggregates. These homogenous mixtures include micellar solutions and liquid crystalline... 

In 1906 Albert Einstein (Nobel Prize, 1921) published his first derivation of an expression for the viscosity of a dilute dispersion of solid spheres. The initial theory contained errors that were corrected in a subsequent paper that appeared in 1911. It would be no mistake to infer from the historical existence of this error that the theory is complex. Therefore we restrict our discussion to an abbreviated description of the assumptions of the theory and some highlights of the derivation. Before examining the Einstein theory, let us qualitatively consider what effect the presence of dispersed particles is expected to have on the viscosity of a fluid. 

Would you walk up to a soda fountain and order a triple, chocolate-flavored colloidal dispersion No Yet that s what you do when you ask for a chocolate sundae. Ice cream is a colloidal dispersion of solids in a liquid so is chocolate syrup. Whipped cream is a colloidal dispersion of air in a liquid. 

Dispersion of Solid (third phase) in Water/Reactor Solid Solute (M)/ Adsorptive (M) Main Purpose References... 

Gas anti-solvent processes (GASR, gas anti-solvent recrystallization GASP, gas antisolvent precipitation SAS, supercritical anti-solvent fractionation PCA, precipitation with a compressed fluid anti-solvent SEDS, solution-enhanced dispersion of solids) differ in the way the contact between solution and anti-solvent is achieved. This may be by spraying the solution in a supercritical gas, spraying the gas into the liquid solution. 

In the food industry it has often been difficult to obtain true viscosity measurements (unithj.j) of complex fluid foods such as coarse fruit suspensions. These are usually non-Newtonian suspensions. Fruit concentrates are dispersions of solid particles (pulp) in aqueous media (serum). Their rheological properties are of interest in practical applications related to processing, storage stability, and sensory properties. Expensive rheometers are often not available in quality control and product development laboratories. However, viscosity is nonetheless an important quality factor of these products. 

SN1 and reactions Two varieties of nucleophilic substitution, with unimolecular and bimolecular ratedetermining stages, respectively, sol A colloidal dispersion of solid particles in a liquid, solid A rigid form of matter that maintains the same shape whatever the shape of its container, solid emulsion A colloidal dispersion of a liquid in a solid. Example butter, an emulsion of water in butterfat. solid solution A solid homogeneous mixture of two or more substances. 

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