5,060 research outputs found
An obstruction based approach to the Kochen-Specker theorem
In [1] it was shown that the Kochen Specker theorem can be written in terms
of the non-existence of global elements of a certain varying set over the
partially ordered set of boolean subalgebras of projection operators on some
Hilbert space. In this paper, we show how obstructions to the construction of
such global elements arise, and how this provides a new way of looking at
proofs of the theorem.Comment: 14 pages, 6 figure
The origin ofhigh hydraulic resistance for filter cakes ofdef ormable particles: cell-bed deformation or surface-layer effect?
This study reports a numerical approach for modeling the hydraulic resistance ofa filter cake ofdef ormable cells. First, a mechanical and osmotic model that describes the volume fraction ofsolids in a bed ofyeast cells as a function ofthe compressive pressure it experiences
is presented. The effects ofpressure on the compressibility ofyeast cells beds were further investigated both by filtration experiments and by centrifugal experiments based on the multiple speed equilibrium sediment height technique. When comparing the latter measurements
with compression model calculations, we observed that the method based on centrifugal experiments suffers from rapid relaxation of the compressed bed. Concerning the filtration experiments, specific resistance ofwell-defined bed ofcells were calculated by a combination of
the compression model with a formulation for hydraulic resistivity developed using the Lattice Boltzmann method. We further explain the experimental values observed for the hydraulic resistance ofcell beds, assuming that the first layer ofcells in contact with the membrane partially blocks the membrane area open to flow. In such a case, the blocked area seems to be a constant fraction of the normal cell–cell
contact area
Kochen-Specker Obstruction for Position and Momentum Using a Single Degree of Freedom
It is shown that, given a reasonable continuity assumption regarding
possessed values, it is possible to construct a Kochen-Specker obstruction for
any coordinate and its conjugate momentum, demonstrating that at most one of
these two quantities can have a noncontextual value.Comment: This version replaces v1, which contained a faulty continuity
condito
Growth and Survival of Largemouth Bass in Newly Stocked South Dakota Impoundments
The present study was designed to evaluate the effect of five different stocking combinations and differences in climatic and morphological conditions within South Dakota on initial growth and survival of the largemouth bass (Micropertus salmoides). Forage species stocked with bass included gold shiners (Notemigonus crysoleucas), fathead minnow (Pimephales promelas), black bullhead (Ictalurus melas), and bluegill (Lepomis macrochirus). Bass only stocking was also evaluated. First eyar survival values for 16 eastern South Dakota ponds ranged from 1 to 100%, with a mean of 50.2%. Bass exhibited poorest survival when stocked with black bullheads. Analysis of variance indicated no significant difference (P\u3e.05) in first year bass growth due to the different forage options stocked. Differences in first year bass growth were significant due to geographic region of the state stocked, however. First year bass growth rates in 34 ponds ranged from 101.0 to 196.5 mm with a mean of 153.2 mm. Second year growth of bass calculated from fish sampled in September 1980 averaged 275.7 mm for eight southeastern South Dakota ponds. Index of relative weight (Wr) was computed to determine bass condition. Calculated Wr values ranged from 100.1 to 134.6, with an average for 34 ponds of 113.6. No significant differences were observed among quadrats or combinations. Stepwise multiple regression of selected chemical, physical, and biological parameters indicated that the number of growing days, turbidity, presence/absence of fathead minnows, and salinity were important factors influencing first year bass growth in this study
Direct Calculation of Configurational Entropy: Pair Correlation Functions and Disorder
Techniques such as classical molecular dynamics [MD] simulation provide ready access to the thermodynamic data of model material systems. However, the calculation of the Helmholtz and Gibbs free energies remains a difficult task due to the tedious nature of extracting accurate values of the excess entropy from MD simulation data. Thermodynamic integration, a common technique for the calculation of entropy requires numerous simulations across a range of temperatures. Alternative approaches to the direct calculation of entropy based on functionals of pair correlation functions [PCF] have been developed over the years. This work builds upon the functional approach tradition by extending the recently developed entropy pair functional theory [EPFT] to three new material systems. Direct calculations of entropy for the BCC iron and FCC copper (modeled with the modified embedded atom method [MEAM] potential) and the Diamond Cubic silicon system (modeled with the Tersoff potential) are compared against a target entropy as determined by thermodynamic integration. The sources of and correction to the high temperature error in several proposed functional approaches is explored in depth. Finally, a working code is provided to the community via Github to implement the extended EFPT to compute entropy using trajectory files generated from a single simulation
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