3,253 research outputs found

    Cryogenic fluid management experiment

    Get PDF
    The cryogenic fluid management experiment (CFME), designed to characterize subcritical liquid hydrogen storage and expulsion in the low-q space environment, is discussed. The experiment utilizes a fine mesh screen fluid management device to accomplish gas-free liquid expulsion and a thermodynamic vent system to intercept heat leak and control tank pressure. The experiment design evolved from a single flight prototype to provision for a multimission (up to 7) capability. A detailed design of the CFME, a dynamic test article, and dedicated ground support equipment were generated. All materials and parts were identified, and components were selected and specifications prepared. Long lead titanium pressurant spheres and the flight tape recorder and ground reproduce unit were procured. Experiment integration with the shuttle orbiter, Spacelab, and KSC ground operations was coordinated with the appropriate NASA centers, and experiment interfaces were defined. Phase 1 ground and flight safety reviews were conducted. Costs were estimated for fabrication and assembly of the CFME, which will become the storage and supply tank for a cryogenic fluid management facility to investigate fluid management in space

    Behavior of fluids in a weightless environment

    Get PDF
    Fluid behavior in a low-g environment is controlled primarily by surface tension forces. Certain fluid and system characteristics determine the magnitude of these forces for both a free liquid surface and liquid in contact with a solid. These characteristics, including surface tension, wettability or contact angle, system geometry, and the relationships governing their interaction, are discussed. Various aspects of fluid behavior in a low-g environment are then presented. This includes the formation of static interface shapes, oscillation and rotation of drops, coalescence, the formation of foams, tendency for cavitation, and diffusion in liquids which were observed during the Skylab fluid mechanics science demonstrations. Liquid reorientation and capillary pumping to establish equilibrium configurations for various system geometries, observed during various free-fall (drop-tower) low-g tests, are also presented. Several passive low-g fluid storage and transfer systems are discussed. These systems use surface tension forces to control the liquid/vapor interface and provide gas-free liquid transfer and liquid-free vapor venting

    Real Springer fibers and odd arc algebras

    Get PDF
    We give a topological description of the two-row Springer fiber over the real numbers. We show its cohomology ring coincides with the oddification of the cohomology ring of the complex Springer fiber introduced by Lauda-Russell. We also realize Ozsv\'ath-Rasmussen-Szab\'o odd TQFT from pullbacks and exceptional pushforwards along inclusion and projection maps between hypertori. Using these results, we construct the odd arc algebra as a convolution algebra over components of the real Springer fiber, giving an odd analogue of a construction of Stroppel-Webster

    Rapid Response Plan for Management and Control of the Chinese Mitten Crab, Northeast United States and Atlantic Canada

    Get PDF
    The Rapid Response Plan for Management and Control of the Chinese Mitten Crab is intended to guide efforts to mitigate the further introduction and spread of the Chinese mitten crab in the northeastern United States and Canada. Due to the unique challenges of invasive species introductions to marine and coastal ecosystems, the mitten crab and other existing and potential marine invasive species are more difficult and often more costly to manage or control than freshwater aquatic or terrestrial invasive species. These challenges include ecosystem connectivity across vast geographic areas, ocean currents and tidal influence, and shipping- and ballast-related vectors for larvae. Warming ocean and coastal waters and species range expansions influenced by climate change will further compound these issues. Recent and historical efforts to control or eradicate invasive mitten crab populations in other countries and in other parts of the United States have not been effective. More than a century of efforts to control or eradicate other marine invasive species, such as the European green crab, has also proven unsuccessful. For these reasons, it is prudent to focus available funds and regional capacity for early detection and rapid response planning on prevention, as we must assume that eradication is not likely should Chinese mitten crabs enter Rhode Island, Massachusetts, New Hampshire, Maine or Maritime Canada. The Sea Grant Programs in Massachusetts, New Hampshire and Maine worked with local, state, regional and federal stakeholders to establish a foundation for prevention, early detection and rapid response efforts of the Chinese mitten crab

    Cooling and heating by adiabatic magnetization in the Ni50_{50}Mn34_{34}In16_{16} magnetic shape memory alloy

    Get PDF
    We report on measurements of the adiabatic temperature change in the inverse magnetocaloric Ni50_{50}Mn34_{34}In16_{16} alloy. It is shown that this alloy heats up with the application of a magnetic field around the Curie point due to the conventional magnetocaloric effect. In contrast, the inverse magnetocaloric effect associated with the martensitic transition results in the unusual decrease of temperature by adiabatic magnetization. We also provide magnetization and specific heat data which enable to compare the measured temperature changes to the values indirectly computed from thermodynamic relationships. Good agreement is obtained for the conventional effect at the second-order paramagnetic-ferromagnetic phase transition. However, at the first order structural transition the measured values at high fields are lower than the computed ones. Irreversible thermodynamics arguments are given to show that such a discrepancy is due to the irreversibility of the first-order martensitic transition.Comment: 5 pages, 4 figures. Accepted for publication in the Physical Review

    Visualização de dados de imagens de sensoriamento remoto.

    Get PDF
    Resumo: Geralmente, os dados de sensoriamento remoto são representados em imagens que reproduzem feições da superfície terrestre. Entretanto, imagens são compostas por dados quantitativos multivariados que podem ser trabalhados de diversas formas para produzir visualizações diferentes das reproduções pictóricas tradicionais. Dados que podem parecer sem valor, como das áreas cobertas por nuvens, podem revelar-se fonte de importante informação para o planejamento de trabalhos futuros. O Brasil tem grande importância na produção agrícola mundial e as culturas mais importantes no país são a soja, o milho e a cana-de-açúcar, que ocuparam 27,7, 15,9 e 8,7 milhões de hectares, respectivamente, na safra 2012/2013. Aproximadamente 40% desta produção se localiza em São Paulo, Paraná, Santa Catarina e Rio Grande do Sul. Imagens de satélite mostram potencial na estimativa de áreas ocupadas pela agricultura de larga escala. Entretanto, para que se possa obter imagens úteis é preciso que não haja nuvens, o que não é comum nos períodos chave dentro do calendário agrícola dessas culturas na região estudada. Obter imagens livres de nuvens ainda é um grande desafio para o monitoramento da agricultura em escala estadual ou nacional. Este trabalho objetivou demonstrar que o tratamento gráfico de dados oriundos de imagens de sensoriamento remoto pode produzir resultados úteis. Para tanto, foi analisada a frequência de imagens livres de nuvens sobre estados ou mesorregiões, ao longo dos meses, com base em uma série temporal de 2000 a 2013, a partir de dados obtidos pelo sensor MODIS e extraídos utilizando uma rotina do R. Abstract: Our goal was to demonstrate that the graph data processing of remote sensing images can produce useful results. We analyzed the frequency of cloud free images over Brazilian states, using a time series from 2000 to 2013, extracted from the MODIS sensor data and using a routine R

    On Binary Matroid Minors and Applications to Data Storage over Small Fields

    Full text link
    Locally repairable codes for distributed storage systems have gained a lot of interest recently, and various constructions can be found in the literature. However, most of the constructions result in either large field sizes and hence too high computational complexity for practical implementation, or in low rates translating into waste of the available storage space. In this paper we address this issue by developing theory towards code existence and design over a given field. This is done via exploiting recently established connections between linear locally repairable codes and matroids, and using matroid-theoretic characterisations of linearity over small fields. In particular, nonexistence can be shown by finding certain forbidden uniform minors within the lattice of cyclic flats. It is shown that the lattice of cyclic flats of binary matroids have additional structure that significantly restricts the possible locality properties of F2\mathbb{F}_{2}-linear storage codes. Moreover, a collection of criteria for detecting uniform minors from the lattice of cyclic flats of a given matroid is given, which is interesting in its own right.Comment: 14 pages, 2 figure

    Passive Retention/Expulsion Methods for Subcritical Storage of Cryogens

    Get PDF
    Development of passive retention/expulsion system for subcritical storage of cryogenic material during low gravity situation

    Fast Neutron And Gamma-ray Detectors For The Csiro Air Cargo Scanner

    Get PDF
    oS(FNDA2006)074 © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence

    Enhancing mental health with Artificial Intelligence: Current trends and future prospects

    Get PDF
    Artificial Intelligence (AI) has emerged as a transformative force in various fields, and its application in mental healthcare is no exception. Hence, this review explores the integration of AI into mental healthcare, elucidating current trends, ethical considerations, and future directions in this dynamic field. This review encompassed recent studies, examples of AI applications, and ethical considerations shaping the field. Additionally, regulatory frameworks and trends in research and development were analyzed. We comprehensively searched four databases (PubMed, IEEE Xplore, PsycINFO, and Google Scholar). The inclusion criteria were papers published in peer-reviewed journals, conference proceedings, or reputable online databases, papers that specifically focus on the application of AI in the field of mental healthcare, and review papers that offer a comprehensive overview, analysis, or integration of existing literature published in the English language. Current trends reveal AI's transformative potential, with applications such as the early detection of mental health disorders, personalized treatment plans, and AI-driven virtual therapists. However, these advancements are accompanied by ethical challenges concerning privacy, bias mitigation, and the preservation of the human element in therapy. Future directions emphasize the need for clear regulatory frameworks, transparent validation of AI models, and continuous research and development efforts. Integrating AI into mental healthcare and mental health therapy represents a promising frontier in healthcare. While AI holds the potential to revolutionize mental healthcare, responsible and ethical implementation is essential. By addressing current challenges and shaping future directions thoughtfully, we may effectively utilize the potential of AI to enhance the accessibility, efficacy, and ethicality of mental healthcare, thereby helping both individuals and communities
    corecore