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Equilibrium Predictions (equilibrium + prediction)

Distribution by Scientific Domains
Life Sciences50%

Selected Abstracts

Stochastic Modeling of Affinity Adsorption

BIOTECHNOLOGY PROGRESS, Issue 3 2001
John Hubble
A stochastic model is described that allows surface proximity and packing effects to be incorporated into predictions of adsorption kinetics and equilibrium of affinity adsorption. Equilibrium predictions show that, depending on conditions chosen, the results obtained for equilibrium conditions can exhibit either a Freundlich- or a Langmuir-type relationship. Under conditions of surface density imposed adsorption constraints, the time taken for equilibrium to be reached increases as the "off" constant is decreased. This suggests that for resins having a high immobilized ligand density binding kinetics may be more highly limited by the "off" constant than by mass transfer limitations. [source]

POSTED OFFER MARKETS IN NEAR-CONTINUOUS TIME: AN EXPERIMENTAL INVESTIGATION

ECONOMIC INQUIRY, Issue 3 2009
DOUGLAS D. DAVIS
This paper reports an experiment conducted to evaluate a "near-continuous" variant of the posted offer trading institution, where the number of periods in a market session is increased by reducing sharply each period's maximum length. Experimental results suggest that although decisions in time-truncated periods are not equivalent to periods of longer duration, extensive repetition improves considerably the drawing power of equilibrium predictions in some challenging environments. Nevertheless, significant deviations remain in the near-continuous framework. We also observe that the extra data collected in the near-continuous framework allow new insights into price convergence and signaling. (JEL C92, L12, L11) [source]

The dynamics of top-down and bottom-up effects in food webs of varying prey diversity, composition, and productivity

OIKOS, Issue 2 2007
Jeremy W. Fox
Prey diversity is thought to mediate the strength of top-down and bottom-up effects, but few experiments directly test this hypothesis. I assembled food webs of bacteria and bacterivorous protist prey in laboratory microcosms with all combinations of five productivity levels, two top predator treatments (present or absent), and three prey compositions. Depauperate food chains contained one of two edible prey species, while more diverse food webs contained both edible prey species plus two additional less-edible/inedible prey. Equilibrium theory predicts that prey diversity should weaken the top-down and bottom-up effects on trophic level biomasses, due to density compensation among prey species. Top-down effects should increase with productivity in food chains, but decrease with productivity in food webs. Results revealed highly dynamic top-down effects, the strength of which varied more over time than among treatments. Further, top-down effects did not merely vary in absolute strength over time, but also in relative strength across different prey compositions and productivity levels. It might be expected that equilibrium models would qualitatively reproduce time-averaged results. However, time-averaged data largely failed to support equilibrium predictions. This failure may reflect strong temporal variability in treatment effects combined with nonlinear density dependence of species' per-capita growth rates. Strong temporal variability in the strength of top-down effects has not previously been demonstrated, but likely is common in nature as well. [source]

Optical Pyrometry of Fireballs of Metalized Explosives

PROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 3 2006
Samuel Goroshin
Abstract Fast-response optical diagnostics (a time-integrated spectrometer and two separate fast-response three-color pyrometers) are used to record the transient visible radiation emitted by a fireball produced when a condensed explosive is detonated. Measurement of the radiant intensity, in several narrow wavelength bands, is used to estimate the temperature of the condensed products within the fireball. For kg-scale conventional oxygen-deficient homogeneous TNT and nitromethane explosive charges, the radiant intensity reaches a maximum typically after tens of milliseconds, but the measured fireball temperature remains largely constant for more than 100,ms, at a value of about 2,000,K, consistent with predictions using equilibrium thermodynamics codes. When combustible metal particles (aluminum, magnesium or zirconium) are added to the explosive, reaction of the particles enhances the radiant energy and the fireball temperature is increased. In this case the fireball temperatures are lower than equilibrium predictions, but are consistent with measurements of particle temperature in single particle ignition experiments. [source]