5,382 research outputs found

    Candidate thermal energy storage technologies for solar industrial process heat applications

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    A number of candidate thermal energy storage system elements were identified as having the potential for the successful application of solar industrial process heat. These elements which include storage media, containment and heat exchange are shown

    Economic Crises: Evidence and Insights from East Asia

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    macroeconomics, Economic Crises, East Asia

    ALCOA #1 (41AN87): A Frankston Phase Settlement along Mound Prairie Creek, Anderson County, Texas

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    The ALCOA #1 (41AN87) site is a Frankston Phase (ca. A.D. 1400-1650) site located on a high alluvial terrace of Mound Prairie Creek, about seven kilometers northeast of Palestine, Texas. Mound Prairie Creek, a perennial stream, flows southeast to east across the county and drains into the Neches River. The site is approximately 10 meters above the Mound Prairie Creek floodplain, and the creek channel is 300 meters to the south. Although the investigations at the site have been rather limited to date, it appears that the ALCOA #1 site is a single component Frankston Phase homestead, or possibly a small hamlet. Other Frankston phase sites are known on Mound Prairie Creek, Hurricane Creek, Walnut Creek, and Brushy Creek, all Neches River tributaries, and the possibility exists that these may be part of a larger related Caddo community and settlement system

    A new look at C*-simplicity and the unique trace property of a group

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    We characterize when the reduced C*-algebra of a group has unique tracial state, respectively, is simple, in terms of Dixmier-type properties of the group C*-algebra. We also give a simple proof of the recent result by Breuillard, Kalantar, Kennedy and Ozawa that the reduced C*-algebra of a group has unique tracial state if and only if the amenable radical of the group is trivial.Comment: 8 page

    Closed loop spray cooling apparatus

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    A closed loop apparatus for spraying coolant against the back of a radiation target is described. The coolant was circulated through a closed loop with a bubble of inert gas being maintained around the spray. Mesh material was disposed between the bubble and the surface of the liquid coolant which was below the bubble at a predetermined level. In a second embodiment, no inert gas was used, the bubble consisting of a vapor produced when the coolant was sprayed against the target

    The Determinants of National Innovative Capacity

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    Motivated by differences in R&D productivity across advanced economies, this paper presents an empirical examination of the determinants of country-level production of international patents. We introduce a novel framework based on the concept of national innovative capacity. National innovative capacity is the ability of a country to produce and commercialize a flow of innovative technology over the long term. National innovative capacity depends on the strength of a nation's common innovation infrastructure (cross-cutting factors which contribute broadly to innovativeness throughout the economy), the environment for innovation in its leading industrial clusters, and the strength of linkages between these two areas. We use this framework to guide our empirical exploration into the determinants of country-level R&D productivity, specifically examining the relationship between international patenting (patenting by foreign countries in the United States) and variables associated with the national innovative capacity framework. While acknowledging important measurement issues arising from the use of patent data, we provide evidence for several findings. First, the production function for international patents is surprisingly well-characterized by a small but relatively nuanced set of observable factors, including R&D manpower and spending, aggregate policy choices such as the extent of IP protection and openness to international trade, and the share of research performed by the academic sector and funded by the private sector. As well, international patenting productivity depends on each individual country's knowledge stock.' Further, the predicted level of national innovative capacity has an important impact on more downstream commercialization and diffusion activities (such as achieving a high market share of high-technology export markets). Finally, there has been convergence among OECD countries in terms of the estimated level of innovative capacity over the past quarter century.

    Formation of plasma around a small meteoroid: 1. Kinetic theory

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    This article is a companion to Dimant and Oppenheim [2017] https://doi.org/10.1002/2017JA023963.This paper calculates the spatial distribution of the plasma responsible for radar head echoes by applying the kinetic theory developed in the companion paper. This results in a set of analytic expressions for the plasma density as a function of distance from the meteoroid. It shows that at distances less than a collisional mean free path from the meteoroid surface, the plasma density drops in proportion to 1/R where R is the distance from the meteoroid center; and, at distances much longer than the mean‐free‐path behind the meteoroid, the density diminishes at a rate proportional to 1/R2. The results of this paper should be used for modeling and analysis of radar head echoes.This work was supported by NSF grant AGS-1244842. (AGS-1244842 - NSF

    Critical research and advanced technology (CRT) support project

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    A critical technology base for utility and industrial gas turbines by planning the use of coal-derived fuels was studied. Development tasks were included in the following areas: (1) Combustion - investigate the combustion of coal-derived fuels and methods to minimize the conversion of fuel-bound nitrogen to NOx; (2) materials - understand and minimize hot corrosion; (3) system studies - integrate and focus the technological efforts. A literature survey of coal-derived fuels was completed and a NOx emissions model was developed. Flametube tests of a two-stage (rich-lean) combustor defined optimum equivalence ratios for minimizing NOx emissions. Sector combustor tests demonstrated variable air control to optimize equivalence ratios over a wide load range and steam cooling of the primary zone liner. The catalytic combustion of coal-derived fuels was demonstrated. The combustion of coal-derived gases is very promising. A hot-corrosion life prediction model was formulated and verified with laboratory testing of doped fuels. Fuel additives to control sulfur corrosion were studied. The intermittent application of barium proved effective. Advanced thermal barrier coatings were developed and tested. Coating failure modes were identified and new material formulations and fabrication parameters were specified. System studies in support of the thermal barrier coating development were accomplished

    Multiple Quantum NMR and Entanglement Dynamics in Dipolar Coupling Spin

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    We investigate numerically the time dependence of the multiple quantum coherences and entanglement in linear chains up to nine nuclear spins of 1/2 coupled by the dipole-dipole interactions. Two models are considered: (1) a spin chain with nearest-neighbor dipole -dipole interactions; (2) a more realistic model with interactions between all spins. It is shown that the entangled states appear between remote particles which do not interact directly (model 1), while the interaction between all spins (model 2) not always results in entanglement between remote spins.Comment: 14 pages, 3 figures. accepted for publication in Physical Review
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