1,352 research outputs found

    Study to establish cost predictions for the production of Redox chemicals

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    The chromium and iron chloride chemicals are significant first costs for NASA Redox energy storage systems. This study was performed to determine the lowest cost at which chromium and iron chlorides could be obtained for a complex of redox energy storage systems. In addition, since the solutions gradually become intermixed during the course of operation of Redox units, it was an objective to evaluate schemes for regeneration of the operating solutions. Three processes were evaluated for the production of chromium and iron chlorides. As a basis for the preliminary plant design and economic evaluation, it was assumed that the plant would produce about 25,000 tons of contained chromium as CrCl3 and an equivalent molar quantity of FeCl2. Preliminary plant designs, including materials and energy balances and sizing of major equipment, were prepared, and capital and operating costs were estimated

    On Determining a Labor Relations Policy for the New Mexico State Career Service

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    This thesis has for its purpose to determine whether New Mexico should enact a collective bargaining law or a meet and confer II law, in order to regulate labor relations in the State career service. The reasons for undertaking such a study are clear. Public employees in the State service are organizing at a rapid rate, and the legal structure under which public administrators are negotiating agreements is inadequate. In 1975, the Thirty-Second New Mexico Legislature attempted to resolve this problem by considering two legislative proposals designed to regulate the conduct of employee-management relations in the public employment sector. Neither proposal was enacted into law; yet the need for a firm policy still remains. HB 91, entitled the Public Employee Bargaining Act, proposed to authorize the right of New Mexico public employees to bargain collectively with their employers on matters of wages, hours, benefits, and other conditions and terms of employment. SB 199, entitled the Public Employees Labor Relations Act, proposed not to authorize collective bargaining, but rather to provide a formalized grievance procedures program which would have allowed public employees to meet and confer with their employers in an effort to resolve disputes or complaints arising over general personnel policy and practices. As this study notes, public policies supporting either approach can be found, and in actual practice throughout the various states, are considered the only two viable methods for Legislatures to consider. In order to accomplish the purpose of the study, an extensive research investigation of attorney general opinions, judicial rulings, and current policy in New Mexico and other states was carried out in order to test the hypothesis that when the constructs of a collective bargaining law and a meet and confer law are examined, each on their own merits, and in terms of their individual objectives, the weight of evidence will fall in favor of legislating a public policy endorsing a collective bargaining law rather than a meet and confer law. Basically, the methods employed in this investigation involve a comparative analysis between the two recent New Mexico legislative proposals and the existing legislation of those states which currently regulate labor relations in their public employment sectors

    Properties of high emittance materials

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    High emittance coating materials for beryllium, niobium-zirconium compounds, and stainless steel used in spacecraft radiator

    Non Profit Housing Providers: Can They Survive the \u27Devolution Revolution\u27?

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    This article examines the potential of nonprofit housing providers to participate effectively in housing programs linked to the welfare reform self-sufficiency movement. It reviews proposals for housing reforms which address expanded roles for nonprofit housing providers. With actual experiences of nonprofits as a framework, it explains their organizational patterns. Further, the article explores the supportive services and incentive programs commonly included in self-sufficiency programs employed by nonprofits and suggests modifications to such programs to improve upward mobility for participants. The authors acknowledge that self-sufficiency plans are not for everyone, and suggests alternative schemes for serving those segments of the population which are not likely to benefit from these programs. After reviewing the housing continuum from shelter through transitional housing to permanent housing, with special emphasis on the traditional role nonprofits have played, the authors propose a three part housing strategy that emphasizes responsibility, rather than self-sufficiency, as the standard for continuing housing assistance. The article concludes with the argument that nonprofits need greater regulatory flexibility to enable them to reach their potential

    A study of quantum decoherence in a system with Kolmogorov-Arnol'd-Moser tori

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    We present an experimental and numerical study of the effects of decoherence on a quantum system whose classical analogue has Kolmogorov-Arnol'd-Moser (KAM) tori in its phase space. Atoms are prepared in a caesium magneto-optical trap at temperatures and densities which necessitate a quantum description. This real quantum system is coupled to the environment via spontaneous emission. The degree of coupling is varied and the effects of this coupling on the quantum coherence of the system are studied. When the classical diffusion through a partially broken torus is < hbar, diffusion of quantum particles is inhibited. We find that increasing decoherence via spontaneous emission increases the transport of quantum particles through the boundary.Comment: 19 pages including 6 figure

    Advancement of the 10-species subgingival Zurich Biofilm model by examining different nutritional conditions and defining the structure of the in vitro biofilms

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    BACKGROUND: Periodontitis is caused by a highly complex consortium of bacteria that establishes as biofilms in subgingival pockets. It is a disease that occurs worldwide and its consequences are a major health concern. Investigations in situ are not possible and the bacterial community varies greatly between patients and even within different loci. Due to the high complexity of the consortium and the availability of samples, a clear definition of the pathogenic bacteria and their mechanisms of pathogenicity are still not available. In the current study we addressed the need of a defined model system by advancing our previously described subgingival biofilm model towards a bacterial composition that reflects the one observed in diseased sites of patients and analysed the structure of these biofilms. RESULTS: We further developed the growth media by systematic variation of key components resulting in improved stability and the firm establishment of spirochetes in the 10-species subgingival Zurich biofilm model. A high concentration of heat-inactivated human serum allowed the best proliferation of the used species. Therefore we further investigated these biofilms by analysing their structure by confocal laser scanning microscopy following fluorescence in situ hybridisation. The species showed mutual interactions as expected from other studies. The abundances of all organisms present in this model were determined by microscopic counting following species-specific identification by both fluorescence in situ hybridisation and immunofluorescence. The newly integrated treponemes were the most abundant organisms. CONCLUSIONS: The use of 50% of heat-inactivated human serum used in the improved growth medium resulted in significantly thicker and more stable biofilms, and the quantitative representation of the used species represents the in vivo community of periodontitis patients much closer than in biofilms grown in the two media with less or no human serum. The appearance of T. denticola, P. gingivalis, and T. forsythia in the top layer of the biofilms, and the high abundance of T. denticola, reflects well the microbial situation observed at diseased sites. The improved model biofilms will allow further investigations of interactions between individual species and of the effects of atmospheric or nutritional changes, as well as interactions with tissue cells

    Tethers in space handbook, second edition

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    The Tethers in Space Handbook, Second Edition represents an update to the initial volume issued in September 1986. As originally intended, this handbook is designed to serve as a reference manual for policy makers, program managers, educators, engineers, and scientists alike. It contains information for the uninitiated, providing insight into the fundamental behavior of tethers in space. For those familiar with space tethers, it includes a summary of past and ongoing studies and programs, a complete bibliography of tether publications, and names, addresses, and phone numbers of workers in the field. Perhaps its most valuable asset is the brief description of nearly 50 tether applications which have been proposed and analyzed over the past 10 years. The great variety of these applications, from energy generation to boosting satellites to gravity wave detection is an indication that tethers will play a significant part in the future of space development. This edition of the handbook preserves the major characteristics of the original; however, some significant rearrangements and additions have been made. The first section on Tether Programs has been brought up to date, and now includes a description of TSS-2, the aerodynamic NASA/Italian Space Agency (ASI) mission. Tether Applications follows, and this section has been substantially rearranged. First, the index and cross-reference for the applications have been simplified. Also, the categories have changed slightly, with Technology and Test changed to Aerodynamics, and the Constellations category removed. In reality, tether constellations may be applicable to many of the other categories, since it is simply a different way of using tethers. Finally, to separate out those applications which are obviously in the future, a Concepts category has been added. A new section included here on Conference Summaries recognizes the fact that the tether community is growing internationally, and that meetings provide a means of rapid communication and interaction. Finally, the Bibliography section has been considerably updated to include all known references. These are listed by author and by subject and include the papers to be presented at the Third International Conference in May 1989

    Invertible Dirac operators and handle attachments on manifolds with boundary

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    For spin manifolds with boundary we consider Riemannian metrics which are product near the boundary and are such that the corresponding Dirac operator is invertible when half-infinite cylinders are attached at the boundary. The main result of this paper is that these properties of a metric can be preserved when the metric is extended over a handle of codimension at least two attached at the boundary. Applications of this result include the construction of non-isotopic metrics with invertible Dirac operator, and a concordance existence and classification theorem.Comment: Accepted for publication in Journal of Topology and Analysi

    Changes in extracellular pH during electrical stimulation of isolated rat vagus nerve

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    Double-barrelled pH-sensitive micro-electrodes were used to record changes of extracellular pH during repetitive stimulation of isolated rat vagus nerves. It was found that a small initial alkaline shift was followed by a prolonged acidification. The acidification was correlated in time with the poststimulus undershoot of the extracellular K+ activity and with the recovery phase of the nerve conduction velocity. In the presence of ouabain, the acid component of the pH change was completely abolished (indicating a metabolic origin), whereas the alkaline component remained unaltered. These pH changes were too small to make a significant contribution to the activity-related changes in conduction velocity of the vagal C-fibres
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