12,922 research outputs found

    Utility operational experience on the NASA/DOE MOD-0A 200-kW wind turbine

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    The Mod-0A 200 wind turbine was designed and fabricated as part of the Federal Wind Energy Program. Early wind turbine operation and performance data were obtained while gaining initial experience in the operation of large, horizontal axis wind turbines in typical utility environments. The Mod-0A wind turbine was turned over to the Town of Clayton Light and Water Plant, Clayton, NM, for utility operation and on December 31, 1978, the machine had completed ten months of utility operation. The machine is described and the recent operational experience at Clayton, NMis documented

    Work-related psychological health and psychological type among lead elders within the Newfrontiers network of churches in the United Kingdom

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    Building on a series of recent studies concerned with assessing work-related psychological health and psychological type among various groups of church leaders, this study reports new data provided by 134 Lead Elders within the Newfrontiers network of churches in the United Kingdom who completed the Francis Psychological Type Scales (FPTS) together with the two scales of the Francis Burnout Inventory (FBI) concerned with emotional exhaustion and satisfaction in ministry. Compared with other groups of church leaders, Lead Elders within the Newfrontiers network of churches reported lower levels of emotional exhaustion and higher levels of satisfaction in ministry. Compared with other groups of church leaders, there was a higher proportion of extraverts among Lead Elders within the Newfrontiers network of churches. There was only a weak association between psychological type and burnout

    Variational quantum Monte Carlo simulations with tensor-network states

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    We show that the formalism of tensor-network states, such as the matrix product states (MPS), can be used as a basis for variational quantum Monte Carlo simulations. Using a stochastic optimization method, we demonstrate the potential of this approach by explicit MPS calculations for the transverse Ising chain with up to N=256 spins at criticality, using periodic boundary conditions and D*D matrices with D up to 48. The computational cost of our scheme formally scales as ND^3, whereas standard MPS approaches and the related density matrix renromalization group method scale as ND^5 and ND^6, respectively, for periodic systems.Comment: 4+ pages, 2 figures. v2: improved data, comparisons with exact results, to appear in Phys Rev Let

    An Improved Screen Cone Trap for Monitoring Activity of Flying Insects

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    The traps, as originally described, are difficult to build because the components are soldered together, and the traps must be replaced after three to four summers' use because of rusting. We report here a modified version of the trap that is easier to build, more durable, and more versatile

    Geometric phases and anholonomy for a class of chaotic classical systems

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    Berry's phase may be viewed as arising from the parallel transport of a quantal state around a loop in parameter space. In this Letter, the classical limit of this transport is obtained for a particular class of chaotic systems. It is shown that this ``classical parallel transport'' is anholonomic --- transport around a closed curve in parameter space does not bring a point in phase space back to itself --- and is intimately related to the Robbins-Berry classical two-form.Comment: Revtex, 11 pages, no figures

    Topology and Bistability in liquid crystal devices

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    We study nematic liquid crystal configurations in a prototype bistable device - the Post Aligned Bistable Nematic (PABN) cell. Working within the Oseen-Frank continuum model, we describe the liquid crystal configuration by a unit-vector field, in a model version of the PABN cell. Firstly, we identify four distinct topologies in this geometry. We explicitly construct trial configurations with these topologies which are used as initial conditions for a numerical solver, based on the finite-element method. The morphologies and energetics of the corresponding numerical solutions qualitatively agree with experimental observations and suggest a topological mechanism for bistability in the PABN cell geometry

    Variations in Flight Patterns of European Corn Borer (Lepidoptera: Pyralidae) in New York

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    Seasonal flights of Ostrinia nubilalis (Hübner) were monitored in 1981, using blacklight traps in 28 locations in central and western New York state. Calendar date of peak catch and heat unit accumulations indicated the presence of both univoltine and bivoltine biotypes, although before this study, only the latter was assumed to be present in these regions. Both biotypes were evident at 16 of the 28 trapping sites. Trap catches during the last 5 years of a 15-year study (1967-1981), at a fixed location near Geneva, N. Y., indicated the recurrence of a univoltine population that had last been noted in this region before 1964. Losses due to larval contamination of processed snap beans are reported for 1979 and 1980. Growers of susceptible crops must be aware of local flights and the potential for shifts in peak moth emergence before insecticides are applie
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