Entropy of Open Lattice Systems

We investigate the behavior of the Gibbs-Shannon entropy of the stationary nonequilibrium measure describing a one-dimensional lattice gas, of L sites, with symmetric exclusion dynamics and in contact with particle reservoirs at different densities. In the hydrodynamic scaling limit, L to infinity, the leading order (O(L)) behavior of this entropy has been shown by Bahadoran to be that of a product measure corresponding to strict local equilibrium; we compute the first correction, which is O(1). The computation uses a formal expansion of the entropy in terms of truncated correlation functions; for this system the k-th such correlation is shown to be O(L^{-k+1}). This entropy correction depends only on the scaled truncated pair correlation, which describes the covariance of the density field. It coincides, in the large L limit, with the corresponding correction obtained from a Gaussian measure with the same covariance.Comment: Latex, 28 pages, 4 figures as eps file

Residential Solar Photovoltaics: Comparison of Financing Benefits, Innovations, and Options

This report examines relatively new, innovative financing methods for residential photovoltaics (PV) and compares them to traditional self-financing. It provides policymakers with an overview of the residential PV financing mechanisms, describes relative advantages and challenges, and analyzes differences between them where data is available. Because these innovative financing mechanisms have only been implemented in a few locations, this report can inform their wider adoption

Shift Equivalence of Measures and the Intrinsic Structure of Shocks in the Asymmetric Simple Exclusion Process

We investigate properties of non-translation-invariant measures, describing particle systems on \bbz, which are asymptotic to different translation invariant measures on the left and on the right. Often the structure of the transition region can only be observed from a point of view which is random---in particular, configuration dependent. Two such measures will be called shift equivalent if they differ only by the choice of such a viewpoint. We introduce certain quantities, called translation sums, which, under some auxiliary conditions, characterize the equivalence classes. Our prime example is the asymmetric simple exclusion process, for which the measures in question describe the microscopic structure of shocks. In this case we compute explicitly the translation sums and find that shocks generated in different ways---in particular, via initial conditions in an infinite system or by boundary conditions in a finite system---are described by shift equivalent measures. We show also that when the shock in the infinite system is observed from the location of a second class particle, treating this particle either as a first class particle or as an empty site leads to shift equivalent shock measures.Comment: Plain TeX, 2 figures; [email protected], [email protected], [email protected], [email protected]

Adapting Roof Support Methods for Anchoring Satellites on Asteroids

The use of anchorage in satellite and spacecraft design has been largely restricted to harpoon-inspired technology based on anticipated low strengths of cometary and asteroid material. Initial results from the Rosetta mission to comet 67P/Churyumov- Gerasimenko, however, have demonstrated both larger-than-expected compressive strengths of cometary materials and the importance of adequate anchorage to mitigate the risk of mission failure. The field of rock mechanics can provide unique insight into the design of these satellite and lander anchors by drawing on existing roof bolt technology. This study compared the behavior of tensioned point anchor and untensioned fully-grouted roof bolts with a polyurethane-anchored bolt under environmental conditions similar to those anticipated in space. These conditions include variation in possible material types as well as variations in regolith properties, anchorage length, and low operating temperatures.;Using a Box-Behnken experimental design, this study first compared the effects of anchor depth and rock strength on each of the three anchorage types in a competent rock strength regime. The study then examined the effects of compaction, water content, and temperature on each anchor type in a regolith environment. The subsequent data analysis identified one anchor type as the overall best anchor for these environments. This finding has led to a preliminary design recommendation to advise space agencies on satellite anchor construction based on the target orbital body\u27s anticipated environmental and exogeologic conditions

Assessment of Personality through Behavioral Observations in Work Simulations

This study outlines the development of a rating scale designed to measure personality-related behavior in the context of work simulations. The tool, labeled the Work Simulation Personality Rating Scale (WSPRS), was validated in an assessment center by rating the personality of 123 assessment center participants. Scores from the WSPRS were correlated with corresponding traits from a self-reported personality inventory, and a Trait Activation Potential (TAP) framework was adopted to predict which traits would display best convergence based on assessment center observations. Correlations between the WSPRS dimensions and self-report trait scales ranged from .11 (Neuroticism) to .31 (Extraversion), with the rank-order of convergence exactly reproducing the ordering of the TAP judgments made by the experts

Antarctic Mode Water

An estimate of Southern Ocean volume in temperature-salinity (T-S) classes is made with a focus on cold water masses south of the Polar Front, at depths shallower than 2,000 m. The volumetric diagram for waters below 5° C shows a deficit at temperatures near 0° C and 34.2 psu, surrounded by a ring of larger volumes, related to water mass formation near the Polar Front and near the continental margins as well as mixing effects. The cold, fresh extreme of the Antarctic Intermediate Water T-S relation shows a volumetric maximum, apparently distinct from the interior T-S relationship. We identify this mode as Antarctic Mode Water with a volumetric maximum centered near 2.0° C and 33.9 psu. This maximum lies on a large-scale ridge of high volume representing the Antarctic Surface Water mixed layers south of the Polar Front, at the northern edge of the seasonal sea-ice cover. Additional maxima on the diagram near freezing temperatures seem to be related to processes operating on the slope and shelf, though the data coverage in these regions is much reduced. The origin of the Antarctic Mode Water is ultimately due to sea-ice melt, which systematically shifts the T-S relation of surface water to lower salinities, whereas its thickness and distribution is linked to circumpolar northward Ekman transport and the eddy fluxes of the Polar Front

On the Two Species Asymmetric Exclusion Process with Semi-Permeable Boundaries

We investigate the structure of the nonequilibrium stationary state (NESS) of a system of first and second class particles, as well as vacancies (holes), on L sites of a one-dimensional lattice in contact with first class particle reservoirs at the boundary sites; these particles can enter at site 1, when it is vacant, with rate alpha, and exit from site L with rate beta. Second class particles can neither enter nor leave the system, so the boundaries are semi-permeable. The internal dynamics are described by the usual totally asymmetric exclusion process (TASEP) with second class particles. An exact solution of the NESS was found by Arita. Here we describe two consequences of the fact that the flux of second class particles is zero. First, there exist (pinned and unpinned) fat shocks which determine the general structure of the phase diagram and of the local measures; the latter describe the microscopic structure of the system at different macroscopic points (in the limit L going to infinity in terms of superpositions of extremal measures of the infinite system. Second, the distribution of second class particles is given by an equilibrium ensemble in fixed volume, or equivalently but more simply by a pressure ensemble, in which the pair potential between neighboring particles grows logarithmically with distance. We also point out an unexpected feature in the microscopic structure of the NESS for finite L: if there are n second class particles in the system then the distribution of first class particles (respectively holes) on the first (respectively last) n sites is exchangeable.Comment: 28 pages, 4 figures. Changed title and introduction for clarity, added reference

Geothermal Brief: Market and Policy Impacts Update

Utility-scale geothermal electricity generation plants have generally taken advantage of various government initiatives designed to stimulate private investment. This report investigates these initiatives to evaluate their impact on the associated cost of energy and the development of geothermal electric generating capacity using conventional hydrothermal technologies. We use the Cost of Renewable Energy Spreadsheet Tool (CREST) to analyze the effects of tax incentives on project economics. Incentives include the production tax credit, U.S. Department of Treasury cash grant, the investment tax credit, and accelerated depreciation schedules. The second half of the report discusses the impact of the U.S. Department of Energy's (DOE) Loan Guarantee Program on geothermal electric project deployment and possible reasons for a lack of guarantees for geothermal projects. For comparison, we examine the effectiveness of the 1970s DOE drilling support programs, including the original loan guarantee and industry-coupled cost share programs