2,780 research outputs found

    Magnetic bearings: Fifty years of progress

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    Magnetic bearings are just beginning to be flown in spacecraft systems, but their development spans more than 50 years. The promise of completely noncontacting, unlubricated rotating systems operating at speeds substantially beyond the range of conventional bearings, and with no wear and virtually no vibration, has provided the incentive to develop magnetic bearing technology for many diverse applications. Earnshaw theorized in 1842 that stable magnetic suspension is not possible in all three spatial directions unless the magnetic field is actively controlled. Since that time, researchers have attempted to successfully support spinning rotors in a stable manner. Development of magnetic suspension systems over the past fifty years has included progress on both passive (permanent magnet) and active (electromagnet) systems. The improvements in bearing load capacity, stiffness, and damping characteristics are traced. The trends in rotor size, rotational kinetic energy, and improvements in active control systems capabilities are also reviewed. Implications of superconductivity on suspension system design and performance are discussed

    Effect of Preconditioning on Performance and Health of Feeder Steers

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    Preconditioning may be defined as preparing a calf to better endure stress associated with shipment from the ranch to the feedlot. The South Dakota preconditioning (“Green Tag”) program requires calves be castrated, dehorned and healed by sale time, vaccinated for IBR, BVD, PI and 7-way clostridia, treated for parasites, and be weaned and bunk adjusted for at least 30 days to be considered preconditioned. It is suggested to vaccinate calves at least two weeks before weaning to reduce stress. Advantages to the program would seem to be heavier calves at sale time, reduced transit shrink, reduced sickness and death loss and improved performance in the feedlot. This research is part of a two year study to determine the effects of the “Green Tag” program on calf health and performance

    Geology of Hadley Rille

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    The regional setting, external and internal shape, and materials of Hadley Rille near the Apollo 15 landing site are described. The petrography presented includes lithologies, regolith, talus, and outcrops. The stratigraphy exposed on the rille wall is also considered

    Effect of composition and density on the ablative performance of phenolic-nylon

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    Composition and density effects on ablative performance of phenolic-nylo

    UR-302 Using Quantum Computing to Determine the Optimal Path on Cascading Graphs

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    Quantum computing has completely changed the computing paradigm. These special computers leverage the unique properties of quantum mechanics to solve problems that a classical computer cannot solve in polynomial time. Quantum mechanics such as superposition and entanglement are used to boost computational power exponentially in many problems . Many traditionally NP-complete problems, such as breaking the encryption of public-private key systems, are solvable with quantum computing in polynomial time. In this project, we will review quantum computing basics using real quantum computers and build on those basics to solve a subset of a graph optimization problems using both existing and new methodologies. Our research focuses on a subset of graphs named “Cascading Graphs” and finding the “best” path based on a predetermined metric. To solve this problem, we plan to use a mixed approach for finding a mathematical algorithm and creating an implementation of the algorithm in a quantum computer. This mixed approach will be based on a cycle consisting of trying a find a mathematically rigorous proof and testing different cases to help build an understanding of the problem, which will then be verified using a quantitative approach

    Characterizing the metabolic phenotype of intestinal villus blunting in Zambian children with severe acute malnutrition and persistent diarrhea

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    Background: Environmental enteric dysfunction (EED) is widespread throughout the tropics and in children is associated with stunting and other adverse health outcomes. One of the hallmarks of EED is villus damage. In children with severe acute malnutrition (SAM) the severity of enteropathy is greater and short term mortality is high, but the metabolic consequences of enteropathy are unknown. Here, we characterize the urinary metabolic alterations associated with villus health, classic enteropathy biomarkers and anthropometric measurements in severely malnourished children in Zambia. Methods/Principal findings: We analysed 20 hospitalised children with acute malnutrition aged 6 to 23 months in Zambia. Small intestinal biopsies were assessed histologically (n = 15), anthropometric and gut function measurements were collected and the metabolic phenotypes were characterized by 1H nuclear magnetic resonance (NMR) spectroscopy. Endoscopy could not be performed on community controls children. Growth parameters were inversely correlated with enteropathy biomarkers (p = 0.011) and parameters of villus health were inversely correlated with translocation and permeability biomarkers (p = 0.000 and p = 0.015). Shorter villus height was associated with reduced abundance of metabolites related to gut microbial metabolism, energy and muscle metabolism (p = 0.034). Villus blunting was also related to increased sucrose excretion (p = 0.013). Conclusions/Significance: Intestinal villus blunting is associated with several metabolic perturbations in hospitalized children with severe undernutrition. Such alterations include altered muscle metabolism, reinforcing the link between EED and growth faltering, and a disruption in the biochemical exchange between the gut microbiota and host. These findings extend our understanding on the downstream consequences of villus blunting and provide novel non-invasive biomarkers of enteropathy dysfunction. The major limitations of this study are the lack of comparative control group and gut microbiota characterization

    Documentation of Apollo 15 samples

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    A catalog is presented of the documentation of Apollo 15 samples using photographs and verbal descriptions returned from the lunar surface. Almost all of the Apollo 15 samples were correlated with lunar surface photographs, descriptions, and traverse locations. Where possible, the lunar orientations of rock samples were reconstructed in the lunar receiving laboratory, using a collimated light source to reproduce illumination and shadow characteristics of the same samples shown in lunar photographs. In several cases, samples were not recognized in lunar surface photographs, and their approximate locations are known only by association with numbered sample bags used during their collection. Tables, photographs, and maps included in this report are designed to aid in the understanding of the lunar setting of the Apollo 15 samples

    Is England's public health nutrition system in crisis? A qualitative analysis of the capacity to feed all in need during the COVID-19 pandemic

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    Methodology: An exploratory methodology was adopted to examine experiences relating to capability and capacity among formal and informal helpers within the PHN domain. An online survey, mainly open-ended questions, was used to capture experiences over the period 2010 - 2020. A mixed sampling strategy, including snowball and convenience sampling, via social media and social network contact-sharing approaches, was adopted. Data was analysed using an inductive thematic approach. Results: A total of 89 participants representing the PHN system in England were recruited over two months. Three main themes and eight sub-themes were identified. The first reflected unequivocal accounts of the impact of austerity and the inability of PHN services to meet demand for food security. The second articulated capacity and capability issues within the system, with geographical variations in service delivery, and a lack of connectivity between central, local government, and third sector providers. These were attributed to widening nutrition and health inequalities. Participants felt that the government needed to invest more technical and financial resources to support public health nutrition. They also felt that schools could play a larger role at local level, but there was a need for a clear national recovery plan, setting out a comprehensive and fully supported national strategy to eradicate food insecurity in England Conclusions: Further in-depth research is needed to continue to track the impact of recovery strategies on food insecure people and the capacity of the PHN system. Urgent investment in the capacity and coordination of PHN services is needed to support food insecure people in England. The UK could include the ratification of the right to food in national laws, in line with global commitments already agreed to by the UK State Party
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