16,272 research outputs found

    Environmental effects on silicon solar cells

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    Test results indicate that solder coating cells produces protective or deleterious effect, depending on the environment. Major problem for solder coated cells is in control of solder thickness and uniformity. Problem area for non-solder coated cells is not identified

    One loop effective potential in heterotic M-theory

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    We have calculated the one loop effective potential of the vector multiplets arising from the compactification to five dimensions of heterotic M-theory on a Calabi-Yau manifold with h^{1,1}>1. We find that extensive cancellations between the fermionic and bosonic sectors of the theory cause the effective potential to vanish, with the exception of a higher order curvature term of the type which might arise from string corrections.Comment: Latex, 28 pages, 1 figur

    Investigation of the stall-induced shock wave (hammershock) at the inlet to the engine

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    The peak static pressures measured at the inlet to the engine during stall are presented for a turbojet and two turbofan engines. It is shown for one turbofan and the turbojet that the static pressure ratio across the hammershock does not exceed significantly the normal shock pressure ratio necessary to stop the flow. The second turbofan engine did not follow this rule. Possible reasons for the departure are discussed. For the two turbofan engines the influence of the stall method on the hammershock intensity was investigated. Data related to the spatial distribution of pressure in the hammershock are also presented

    Assessing the Rationality of Farmland Price Movements

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    Replaced with revised version of poster 06/03/11.Agricultural Finance, Farm Management,

    Using Land Values to Predict Future Farm Income

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    land values, almon lag, farm profitability, Agribusiness, Agricultural Finance, Farm Management, Financial Economics, Production Economics,

    The Moderated Relationship of Appearance Valence on Appearance Self Consciousness: Development and Testing of New Measures of Appearance Schema Components

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    This paper describes the creation and psychometric properties of two independent measures of aspects of appearance schematicity - appearance salience and valence, assessed by the CARSAL and CARVAL, and their relation to appearance self-consciousness. Five hundred and ninety two participants provided data in a web based task. The results demonstrate the sound psychometric properties of both scales. This was demonstrated by good item total characteristics, good internal reliability of each scale, and the independence of the two scales shown through principal components analysis. Furthermore, the scales show independent and moderated relationships with valid measures of appearance related psychosocial distress. Negatively valenced appearance information was associated with increased appearance self-consciousness. More crucially, the impact of negative valence on appearance self-consciousness was exacerbated by the moderating effect increased salience of appearance. © 2012 Moss, Rosser

    X-type and Y-type junction stability in domain wall networks

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    We develop an analytic formalism that allows one to quantify the stability properties of X-type and Y-type junctions in domain wall networks in two dimensions. A similar approach might be applicable to more general defect systems involving junctions that appear in a range of physical situations, for example, in the context of F- and D-type strings in string theory. We apply this formalism to a particular field theory, Carter's pentavac model, where the strength of the symmetry breaking is governed by the parameter ϵ<1|\epsilon|< 1. We find that for low values of the symmetry breaking parameter X-type junctions will be stable, whereas for higher values an X-type junction will separate into two Y-type junctions. The critical angle separating the two regimes is given by \alpha_c = 293^{\circ}\sqrt{|\epsilon|} and this is confirmed using simple numerical experiments. We go on to simulate the pentavac model from random initial conditions and we find that the dominant junction is of \ytype for |\epsilon| \geq 0.02 and is of \xtype for |\epsilon| \leq 0.02.Wealsofindthatforsmall. We also find that for small \epsilontheevolutionofthenumberofdomainwalls the evolution of the number of domain walls \qsubrm{N}{dw}inMinkowskispacedoesnotfollowthestandard in Minkowski space does not follow the standard \propto t^{-1}scalinglawwiththedeviationfromthestandardlorebeingmorepronouncedas scaling law with the deviation from the standard lore being more pronounced as \epsilonisdecreased.Thepresenceofdissipationappearstorestorethe is decreased. The presence of dissipation appears to restore the t^{-1}$ lore.Comment: 24 pages, 13 figures; typos fixe

    Mean First Passage Time in Periodic Attractors

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    The properties of the mean first passage time in a system characterized by multiple periodic attractors are studied. Using a transformation from a high dimensional space to 1D, the problem is reduced to a stochastic process along the path from the fixed point attractor to a saddle point located between two neighboring attractors. It is found that the time to switch between attractors depends on the effective size of the attractors, τ\tau, the noise, ϵ\epsilon, and the potential difference between the attractor and an adjacent saddle point as:  T=cτexp(τϵΔU) ~T = {c \over \tau} \exp({\tau \over \epsilon} \Delta {\cal{U}})~; the ratio between the sizes of the two attractors affects ΔU\Delta {\cal{U}}. The result is obtained analytically for small τ\tau and confirmed by numerical simulations. Possible implications that may arise from the model and results are discussed.Comment: 14 pages, 3 figures, submitted to journal of physics

    Star-forming galaxies in low-redshift clusters: Data and integrated galaxy properties

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    This paper is a continuation of an ongoing study of the evolutionary processes affecting cluster galaxies. Both CCD R band and H alpha narrow-band imaging was used to determine photometric parameters (m_(r), r_(24), H alpha flux and equivalent width) and derive star formation rates for 227 CGCG galaxies in 8 low-redshift clusters. The galaxy sample is a subset of CGCG galaxies in an objective prism survey of cluster galaxies for H alpha emission. It is found that detection of emission-line galaxies in the OPS is 85%, 70%, and 50% complete at the mean surface brightness values of 1.25 x 10^(-19), 5.19 x 10^(-20), and 1.76 x 10^(-20) W m^(-2) arcsec^(-2), respectively, measured within the R band isophote of 24 mag arcsec^(-2) for the galaxy. The CCD data, together with matched data from a recent H alpha galaxy survey of UGC galaxies within 3000 km s^(-1), will be used for a comparative study of R band and H alpha surface photometry between cluster and field spirals.Comment: Accepted for publication in A&A. 11 pages, including 6 figure
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