Equilibrium density

The trapping efficiency of polymeric, microporous adsorbents [e.g., polystyrene, polyurethane foam (PUF), Tenax] for compound vapors will be affected by compound vapor density (i. e., equilibrium vapor pressure). The free energy change required in the transition from the vapor state to the condensed state (e.g., on an adsorbent) is known as the adsorption potential (calories per mole), and this potential is proportional to the ratio of saturation to equilibrium vapor pressure. This means that changes in vapor density (equilibrium vapor pressure) for very volatile compounds, or for compounds that are gases under ambient conditions, can have a dramatic effect on the trapping efficiency for polymeric microporous adsorbents. 

Adsorption and electrokinetic effects of amino acids, solid-aqueous interface, 311-26 Adsorption density, equilibrium PAA at various pH values, 299f PAA on hematite, 304f SDS with and without polymer, 298f,303f... 

Exchange current density Equilibrium constant Thermal energy Rate constant Boltzmann constant Thickness of Debye layer... 

A simplified extraction model assumes that both liquids are ideal mixtures and neglects any changes in density. Equilibrium concentrations are then estimated by solving the equation set. 

With known site densities, equilibrium constants for each site, and each solution component, and a way to relate surface potential to surface charge, the distribution of aqueous and surface species can now be solved in the same way as solutions with no surfaces. Bethke (1996) gives details of the method. 

The foregoing equations have resulted from the stated assumptions of the models employed. These models are examples of many models that have been proposed for electrochemical reactions. The equations are accepted here because of their simplicity of form and the fact that they do predict relationships between exchange current density, equilibrium half-cell potential, and concentration, which are frequently observed experimentally. The theories and resulting equations are obviously more complicated for surface reactions, such as the reduction of dissolved oxygen, 02 + 4H+ + 4e — 2H20. Theories for this reaction have proposed as many as eight individual steps. 

Note if you get a definite layer or layers of particles after 24 hours at the boundaries where you added the different solutions, then the column has not reached density equilibrium and should be allowed to set for a while longer. 

Apparent densities, equilibrium forces and retention times obtained with the duplicate 3 factorial design used to study earplug production... 

The direct method includes direct observation by electron microscope and field emission technique structural analysis using X-ray, neutron and electron diffractometry, or channelling technique and also resonance techniques such as ESR, NMR, and Mossbauer absorption. The techniques used in the indirect method include the measurement of a property sensitive to the nonstoichiometric composition, such as lattice constant, density, equilibrium partial pressure, and electric conductivity. The defect structure is estimated from the correspondence between the defect model assumed and the measured change of the property. With the indirect method, it is rather difficult to estimate defect structures more complex than the simple point defect. 

Meyer R W, Kellogg R M, Warren W G 1981 Relative density, equilibrium moisture content and dimensional stability of western hemlock bark. Wood Fiber 13 86-96... 

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