375 research outputs found

    Towards sustainable agriculture: fossil-free ammonia

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    Citation: Pfromm, P. H. (2017). Towards sustainable agriculture: Fossil-free ammonia. Journal of Renewable and Sustainable Energy, 9(3), 034702. https://doi.org/10.1063/1.4985090About 40% of our food would not exist without synthetic ammonia (NH3) for fertilization. Yet, NH3 production is energy intensive. About 2% of the world's commercial energy is consumed as fossil fuels for NH3 synthesis based on the century-old Haber-Bosch (H.-B.) process. The state of the art and the opportunities for reducing the fossil energy footprint of industrial H.-B. NH3 synthesis are discussed. It is shown that even a hypothetical utterly revolutionary H.-B. catalyst could not significantly reduce the energy demand of H.-B. NH3 as this is governed by hydrogen production. Renewable energy-enabled, fossil-free NH3 synthesis is then evaluated based on the exceptional and continuing cost decline of renewable electricity. H.-B. syngas (H2, N2) is assumed to be produced by electrolysis and cryogenic air separation, and then supplied to an existing H.-B. synthesis loop. Fossil-free NH3 could be produced for energy costs of about $232 per tonne NH3 without claiming any economic benefits for the avoidance of about 1.5 tonnes of CO2 released per tonne NH3 compared to the most efficient H.-B. implementations. Research into alternatives to the H.-B. process might be best targeted at emerging markets with currently little NH3 synthesis capacity but significant future population growth such as Africa. Reduced capital intensity, good scale-down economics, tolerance for process upsets and contamination, and intermittent operability are some desirable characteristics of NH3 synthesis in less developed markets, and for stranded resources. Processes that are fundamentally different from H.-B. may come to the fore under these specific boundary conditions

    Developing a conceptual framework for an evaluation system for the NIAID HIV/AIDS clinical trials networks

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    Globally, health research organizations are called upon to re-examine their policies and practices to more efficiently and effectively address current scientific and social needs, as well as increasing public demands for accountability

    Federal R & D funding by budget function.

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    Latest issue consulted: Fiscal years 2001-03.Imprint varies: Washington, DC, 1978-80-1992-94 ; Arlington, VA, 1993-95-<2002>Distributed to depository libraries in microfiche.Title from cover.Each report covers actual funding of previous fiscal year plus funding estimates for current and next fiscal year.Issue for 1992-94 called also: Data update.Mode of access: Internet.Vols. for <1988-90-1989-91> issued by: National Science Foundation, Directorate for Scientific, Technological, and International Affairs, Division of Science Resources Studies, Government Studies Group; 199 -199 -1992-94 by: Science and Engineering Indicators Program, Division of Science Resources Studies, National Science Foundation; 1993-95-1999-2001 by: Division of Science Resources Studies, Directorate for Social, Behavioral and Economic Sciences, National Science Foundation; 2000-2002- <2001-03> by: Division of Science Resources Statistics, Directorate for Social, Behavioral, and Economic Sciences, National Science Foundation.Issues for 1993-95-2002-04 also available online; later issues only available online
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