2,549 research outputs found

    Sabatier Reactor System Integration with Microwave Plasma Methane Pyrolysis Post-Processor for Closed-Loop Hydrogen Recovery

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    The Carbon Dioxide Reduction Assembly (CRA) designed and developed for the International Space Station (ISS) represents the state-of-the-art in carbon dioxide reduction (CDRe) technology. The CRA produces water and methane by reducing carbon dioxide with hydrogen via the Sabatier reaction. The water is recycled to the Oxygen Generation Assembly (OGA) and the methane is vented overboard resulting in a net loss of hydrogen. The proximity to earth and the relative ease of logistics resupply from earth allow for a semi-closed system on ISS. However, long-term manned space flight beyond low earth orbit (LEO) dictates a more thoroughly closed-loop system involving significantly higher recovery of hydrogen, and subsequent recovery of oxygen, to minimize costs associated with logistics resupply beyond LEO. The open-loop ISS system for CDRe can be made closed-loop for follow-on missions by further processing methane to recover hydrogen. For this purpose, a process technology has been developed that employs a microwave-generated plasma to reduce methane to hydrogen and acetylene resulting in 75% theoretical recovery of hydrogen. In 2009, a 1-man equivalent Plasma Pyrolysis Assembly (PPA) was delivered to the National Aeronautics and Space Administration (NASA) for technical evaluation. The PPA has been integrated with a Sabatier Development Unit (SDU). The integrated process configuration incorporates a sorbent bed to eliminate residual carbon dioxide and water vapor in the Sabatier methane product stream before it enters the PPA. This paper provides detailed information on the stand-alone and integrated performance of both the PPA and SDU. Additionally, the integrated test stand design and anticipated future work are discussed

    An investigation to determine the cause of haemorrhagic enteritis in commercial pig grower units in the northern parts of South Africa

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    Necropsies were performed on 36 grower pigs that died peracutely on farms in the northern parts of South Africa. All these pigs were suffering from haemorrhagic enteritis and suspected toxaemia. Samples of the duodenum, jejunum and ileum were taken for histopathological examination and a section of ileum was collected for microbiological examination from each animal. Histological lesions characteristic of enterotoxigenic Clostridium infection were found. Large, Gram-positive bacilli were sometimes abundant in sections and mucosal smears of the intestine. However, only 40% of the cultures were positive for Clostridium perfringens

    IVOA Recommendation: VOTable Format Definition Version 1.3

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    This document describes the structures making up the VOTable standard. The main part of this document describes the adopted part of the VOTable standard; it is followed by appendices presenting extensions which have been proposed and/or discussed, but which are not part of the standard

    Environmental Regulation of Oil and Gas Development on Tribal Lands: Who Has the Authority?

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    14 pages. Collection of 3 papers presented at the Hot Topics in Natural Resources Law program held on Nov. 1, 1995. Includes bibliographical references. Contents: Environmental regulation of oil and gas development on tribal lands : who has authority? / Richard Collins -- Environmental regulation of energy resource development on Indian reservation land / Tom Shipps -- Colorado Oil and Gas [Conservation] Commission jurisdiction over environmental matters on Indian lands / Marla Williams Jurisdiction to regulate the environmental impacts of oil and gas development on the reservation has been contested by tribes, the state, private land owners and federal agencies. Should the state be able to regulate the environmental consequences of this development? Should the tribes? What is the role of the federal government? These questions will be addressed by CU Law Professor Richard Collins, Durango attorney Tom Shipps, and Marla Williams, Colorado Oil and Gas Commissioner

    Environmental Regulation of Oil and Gas Development on Tribal Lands: Who Has the Authority?

    Get PDF
    14 pages. Collection of 3 papers presented at the Hot Topics in Natural Resources Law program held on Nov. 1, 1995. Includes bibliographical references. Contents: Environmental regulation of oil and gas development on tribal lands : who has authority? / Richard Collins -- Environmental regulation of energy resource development on Indian reservation land / Tom Shipps -- Colorado Oil and Gas [Conservation] Commission jurisdiction over environmental matters on Indian lands / Marla Williams Jurisdiction to regulate the environmental impacts of oil and gas development on the reservation has been contested by tribes, the state, private land owners and federal agencies. Should the state be able to regulate the environmental consequences of this development? Should the tribes? What is the role of the federal government? These questions will be addressed by CU Law Professor Richard Collins, Durango attorney Tom Shipps, and Marla Williams, Colorado Oil and Gas Commissioner

    Developing a national indicator of functional connectivity

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    Habitat loss is a significant driver of biodiversity loss, causing fragmentation into small, isolated patches of suitable land cover. This reduces the permeability of landscapes to the movement of individuals and reduces the likelihood of metapopulation persistence. Quantifying functional connectivity, the ability of a focal species to move between resource patches, is therefore essential for conservation management. There is substantial evidence supporting a technique based on ‘population synchrony’- the degree of correlation in time-series of annual population growth rates between different long-term monitoring sites, to provide a measure of functional connectivity. However, synchronised population dynamics are not only driven by the movement of individuals between sites, but also shared environmental conditions which must be accounted for. Here, we use species survey data from over four decades to investigate average levels and temporal trends in population synchrony for 58 British bird and butterfly species. We first show that population synchrony is significantly associated with synchrony in some seasonal climatic variables. Once we accounted for spatiotemporal climatic patterns, we found that synchrony in butterflies declined over time by 71% between 1985 and 2000 but increased by 64% in recent years. Synchrony in birds showed some decline between 1999 and 2005, after which there appears to being recovery, however most species (74%) show no significant overall change in synchrony. Our proposed indicator provides a ‘species-eye-view’ of functional connectivity using widely available abundance data. Developing such indicators of functional connectivity, which can be updated annually, is crucial to improve the effectiveness of land management strategies for conservation under increasing environmental change

    US Conference of Mayors Impact of the Mortgage Foreclosure Crisis on Vacant and Abandoned

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    Development of Models to Simulate Tracer Tests for Characterization of Enhanced Geothermal Systems

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    A recent report found that power and heat produced from enhanced (or engineered) geothermal systems (EGSs) could have a major impact on the U.S energy production capability while having a minimal impact on the environment. EGS resources differ from high-grade hydrothermal resources in that they lack sufficient temperature distribution, permeability/porosity, fluid saturation, or recharge of reservoir fluids. Therefore, quantitative characterization of temperature distributions and the surface area available for heat transfer in EGS is necessary for the design and commercial development of the geothermal energy of a potential EGS site. The goal of this project is to provide integrated tracer and tracer interpretation tools to facilitate this characterization. This project was initially focused on tracer development with the application of perfluorinated tracer (PFT) compounds, non-reactive tracers used in numerous applications from atmospheric transport to underground leak detection, to geothermal systems, and evaluation of encapsulated PFTs that would release tracers at targeted reservoir temperatures. After the 2011 midyear review and subsequent discussions with the U.S. Department of Energy Geothermal Technology Program (GTP), emphasis was shifted to interpretive tool development, testing, and validation. Subsurface modeling capabilities are an important component of this project for both the design of suitable tracers and the interpretation of data from in situ tracer tests, be they single- or multi-well tests. The purpose of this report is to describe the results of the tracer and model development for simulating and conducting tracer tests for characterizing EGS parameters

    ‘Who Is British Music?’ Placing Migrants in National Music History

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    In 2013, trucks and vans were driving across London, bearing the message ‘In the UK illegally? Go home or face arrest.’ These mobile billboards declared the number of arrests that had taken place ‘in your area’ in the previous week and provided a number to which people could text the message ‘HOME’ to initiate voluntary repatriation. In 2016, Theresa May, who had organised this scheme as home secretary, became prime minister, following the upheaval caused by the country's plebiscite to leave the European Union. One of the main strands of argument of the successful ‘Brexit’ campaign centred on the ‘deep public anxiety . . . about uncontrolled immigration’ and promised to reduce numbers of immigrants to the country. This desire to control the nation's borders continued to dominate the official soundscape of Britain's government. At the 2016 annual Tory conference, May endeavoured to draw clear lines on issues of belonging, territory, citizenship, and the fuzzy notion of British values, discursively excluding not only migrants, but also anyone with an international(ist) outlook from the national debate: ‘If you believe you are a citizen of the world’, she posited, ‘you are a citizen of nowhere.
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