706 research outputs found

    Large Deviation Principles and Complete Equivalence and Nonequivalence Results for Pure and Mixed Ensembles

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    We consider a general class of statistical mechanical models of coherent structures in turbulence, which includes models of two-dimensional fluid motion, quasi-geostrophic flows, and dispersive waves. First, large deviation principles are proved for the canonical ensemble and the microcanonical ensemble. For each ensemble the set of equilibrium macrostates is defined as the set on which the corresponding rate function attains its minimum of 0. We then present complete equivalence and nonequivalence results at the level of equilibrium macrostates for the two ensembles.Comment: 57 page

    The Large Deviation Principle for Coarse-Grained Processes

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    The large deviation principle is proved for a class of L2L^2-valued processes that arise from the coarse-graining of a random field. Coarse-grained processes of this kind form the basis of the analysis of local mean-field models in statistical mechanics by exploiting the long-range nature of the interaction function defining such models. In particular, the large deviation principle is used in a companion paper to derive the variational principles that characterize equilibrium macrostates in statistical models of two-dimensional and quasi-geostrophic turbulence. Such macrostates correspond to large-scale, long-lived flow structures, the description of which is the goal of the statistical equilibrium theory of turbulence. The large deviation bounds for the coarse-grained process under consideration are shown to hold with respect to the strong L2L^2 topology, while the associated rate function is proved to have compact level sets with respect to the weak topology. This compactness property is nevertheless sufficient to establish the existence of equilibrium macrostates for both the microcanonical and canonical ensembles.Comment: 19 page

    Tunnel junctions for InP-on-Si solar cells

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    Growing, by metalorganic chemical vapor deposition, a tunnel junction is described, which makes possible and ohmic back contact in an n-on-p InP solar cell on a silicon substrate. The junction between heavily doped layers of p-type InGaAs and n-type InP shows resistance low enough not to affect the performance of these cells. InP solar cells made on n-type Si substrates with this structure were measured with an efficiency of 9.9 percent. Controls using p-type GaAs substrates showed no significant difference in cell performance, indicating that the resistance associated with the tunnel junction is less than about 0.1 ohm/sq cm

    Surf Clams Off the Virginia Coast

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    A study of the hard and soft clam resources of Virginia : annual contract report for the period 1 July 1969 through 30 June 1970, Contract no. 3-77-R-1

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    The fallowing report contains results of our studies from 1 July 1969 through 30 June-1970. Included in this report is a complete summary of all studies related to soft clams. This includes growth rates, recruitment studies, distribution of juveniles, and effects of the dredge on the substrate and on adjacent bottoms. Hard clam studies reported in this report include studies on growth, recruitment, distribution of young, and effects of .the escalator on the bottom

    Levels of the herbicide Diquat in two estuarine molluscs and in the water and mud

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    Soft clams Mya arenaria and oysters Crassostrea virginica were exposed to 0.35 ppm of the herbicide Diquat during June and July 1967 in Nomini Creek Virginia, a tributary of the Potomac. No detectable residue was found in oyster meats or in the water. Meats of soft clams minus the rough integument surrounding the neck, showed no Diquat. The integument, however, contained from 0.00 to 0.05 ppm. Mud samples contained from 1.17 to 7 .14 ppm. It was assumed that Diquat was strongly sorbed on clay particles in sediments; residues in clam integuments were due to trapped clay particles

    Report to the York River Oyster Research Corporation on the physiological response of oysters to several polymeric materials and their derivatives

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    The physiological responses of several polymeric materials and their derivatives, associated with the manufacturing process of pulp, were tested on oysters. It was thought that, when fed in small quantities, these substances might increase shell or meat size or be of value as possible nutritive supplements . The substances tested were divided into two classes. The first, consisting of basic polymeric materials, may occur in natural water s as the result of chemical changes. Representatives of these were indulin C and dextrose. The second class is composed of chemically pure derivatives of the preceding substances. These may appear in trace amounts in natural waters and represent breakdown products of the lignin and carbohydrate substances similar to indulin C and to dextrose. Representatives of this group tested in the following study were glycolic acid, lactic acid, vanillin and catechol

    Survey of cultchless spat planted by the VMRC in Nomini and lower Machodoc Creek

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    As part of a major repletion activity by the VMRC, cultchless spat were planted in Lower Machodoc Creek and Nomini Creek in October and November 1973. The Virginia Institute of Marine Science surveyed these plantings on 10 and 11 December, 1973. The areas planted and surveyed are shown in figures 1 and 2. In Lower Machodoc Creek, 5.35 acres were planted with 240.5 bushels of cultchless spat during October, 1973. Within this area, five sub-areas were seeded, each with about one million spat. In Nomini Creek there were two planting areas. The largest was located in Nomini Cut, and seven one acre sub-areas were delimited here; each receiving about one million spat. One area (15) was planted up-river from Nomini Cut
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