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External phase, definition

A disperse system is defined as a heterogenous, two-phase system in which the internal (dispersed, discontinuous) phase is distributed or dispersed within the continuous (external) phase or vehicle. Various pharmaceutical systems are included in this definition, the internal and external phases being gases, liquids, or solids. Disperse systems are also important in other fields of application, e.g., processing and manufacturing of household and industrial products such as cosmetics, foods, and paints. [Pg.242]

By Descartes rule (on alternation of signs), this general equation can have only one positive real root (5) which then must be the root of physical significance and must lie between 0 and Mtot- In application to a real system, use of the equation in this form requires a method for measuring Ma, and hence it is necessary to distinguish experimentally between M and Pa. Often such a measurement is not possible, and what can be measured is Mff°, the total number of monomer equivalents in the external phase. By definition... [Pg.306]

Definition and Classification of Emulsions. Colloidal droplets (or particles or bubbles), as they are usually defined, have at least one dimension between about 1 and 1000 nm. Emulsions are a special kind of colloidal dispersion one in which a liquid is dispersed in a continuous liquid phase of different composition. The dispersed phase is sometimes referred to as the internal (disperse) phase, and the continuous phase as the external phase. Emulsions also form a rather special kind of colloidal system in that the droplets often exceed the size limit of 1000 nm. In petroleum emulsions one of the liquids is aqueous, and the other is hydrocarbon and referred to as oil. Two types of emulsion are now readily distinguished in principle, depending upon which kind of liquid forms the continuous phase (Figure 2) ... [Pg.5]

In an emulsion, the particles of the internal phase are spherical or liquid droplets that are dispersed throughout a liquid external phase. Even though the particles may be liquid only at elevated temperatures (50-80° C) and semisolid or rigid at room temperature, as long as they appear spherical on careful microscopic examination, they are generally considered to be emulsified rather than suspended. Thus, a clue to the presence of a suspended particle is its lack of sphericity or its definitive lattice structure. Exceptions to this general rule are spherical microspheres and related spherical solid microparticles. [Pg.3597]

The concentrations of point defects, and therefore the direction and degree of nonstoichiometry, are determined by the thermodynamic activities of external phases in equilibrium with the nonstoichiometric compound. For example, the concentration of X vacancies may be controlled by maintaining the crystal in equilibrium with another phase containing X at a definite activity. The external phase may be X2 gas (e.g., O2). The equation for formation of X vacancies then may be written... [Pg.346]

This definition of electrochemistry disregards systems in which nonequilibrium charged species are produced by external action in insulators for example, by electric discharge in the gas phase (electrochemistry of gases) or upon irradiation of liquid and sohd dielectrics (radiation chemistry). At the same time, electrochemistry deals with certain problems often associated with other fields of science, such as the structure and properties of sohd electrolytes and the kinetics of ioific reactions in solutions. [Pg.739]

Consistent with the definition of terms adopted for the discussion in this series of papers of integral phases of the residue studies being conducted by the Division of Entomology, University of California Citrus Experiment Station (2, 13-15), the following distinctions are noted Residues may be specified as pretreatment, posttreatment, harvest, or ultimate. The latter refers to the residue on or in foodstuffs, whether fresh or processed, at the time of consumption (2, 13). The location of residues with reference to fruit parts may be extra-surface (external to the cuticle) or subsurface. Subsurface residues may be differentiated with reference to actual location as cuticular residues or specified intracarp residues. Residues in the cuticular layers or in any of the cellular structures or matrices are herein indicated as subsurface (penetrated) residues (2, 13). [Pg.131]

The electronic microscopy method on the EM-125 (fig. 1) for definition of ZnCFO particles size and characteristic of its surface was applied. Known zinc oxide was chosen as the object of comparison. The electronic photos of powders testify, that new composite and zinc oxide have external similarity under the form of particles, wide range on dispersiveness (0,4-6,0 microns for zinc oxide, fig. la 0,3-6,0 microns for ZnCFO, fig. lb) also contain as crystal as amorphous phases in their structure. [Pg.191]

The term ionization may refer to different processes depending on the context. For radiation effects in the gas phase, it usually implies the removal of the least bound electron to infinity. Such a theoretical definition is not feasible in the condensed phase and it is necessary use a heuristic or operational procedure. Thus, in liquid hydrocarbons, one may use the electron scavenging reaction or a conductivity current to quantify the electrons liberated from molecules. It has only been possible to extrapolate the conductivity current at a low irradiation dose and at a relatively low external field to saturation in the cases of liquefied... [Pg.80]

There are three definitions needed to accurately describe this process. (1) Compaction is the compression and consolidation of a two-phase (particulate solid/gas) system by the application of an external force (2) compression causes an increase in the apparent density (or a reduction in volume) by the displacement of air and (3) consolidation is defined as an increase in mechanical strength due to particle-particle interaction [1,2]. [Pg.222]

By definition, quantum control relies upon the unique quantum properties of light and matter, principally the wavelilce nature of both. As such, maintenance of the phase information contained in both the matter and light is central to the success of the control scenarios. Chapter 5 deals with decoherence, that is, the loss of phase information due to the influence of the external environment in reducing the system coherence. Methods of countering decoherence are also discussed. [Pg.365]

There is no thermodynamic equilibrium between the ideally polarizable electrode (more exactly the metal phase) and the solution phase because there is no common component capable of changing its charge and being transferred between the phases, conditions necessary for equilibrium. The state of an ideally polarizable electrode is well defined only if an external source is used to maintain a constant polarization potential, i.e., the double-layer capacitor charged with a definite charge. The polarization potential is an independent parameter of the system. [Pg.204]


See other pages where External phase, definition is mentioned: [Pg.300]    [Pg.217]    [Pg.549]    [Pg.1548]    [Pg.307]    [Pg.556]    [Pg.247]    [Pg.1532]    [Pg.351]    [Pg.642]    [Pg.86]    [Pg.23]    [Pg.507]    [Pg.316]    [Pg.40]    [Pg.229]    [Pg.83]    [Pg.83]    [Pg.270]    [Pg.1395]    [Pg.267]    [Pg.124]    [Pg.138]    [Pg.218]    [Pg.417]    [Pg.20]    [Pg.102]    [Pg.58]    [Pg.354]    [Pg.109]    [Pg.1030]    [Pg.290]    [Pg.158]   
See also in sourсe #XX -- [ Pg.5 , Pg.393 ]




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Phase, definition

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