79,254 research outputs found

    Foreword

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    Decision-making for unmanned aerial vehicle operation in icing conditions

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    With the increased use of unmanned aerial systems (UAS) for civil and commercial applications, there is a strong demand for new regulations and technology that will eventually permit for the integration of UAS in unsegregated airspace. This requires new technology to ensure sufficient safety and a smooth integration process. The absence of a pilot on board a vehicle introduces new problems that do not arise in manned flight. One challenging and safety-critical issue is flight in known icing conditions. Whereas in manned flight, dealing with icing is left to the pilot and his appraisal of the situation at hand; in unmanned flight, this is no longer an option and new solutions are required. To address this, an icing-related decision-making system (IRDMS) is proposed. The system quantifies in-flight icing based on changes in aircraft performance and measurements of environmental properties, and evaluates what the effects on the aircraft are. Based on this, it determines whether the aircraft can proceed, and whether and which available icing protection systems should be activated. In this way, advice on an appropriate response is given to the operator on the ground, to ensure safe continuation of the flight and avoid possible accidents

    INEL Spray-forming Research

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    Spray forming is a near-net-shape fabrication technology in which a spray of finely atomized liquid droplets is deposited onto a suitably shaped substrate or mold to produce a coherent solid. The technology offers unique opportunities for simplifying materials processing without sacrificing, and oftentimes substantially improving, product quality. Spray forming can be performed with a wide range of metals and nonmetals, and offers property improvements resulting from rapid solidification (e.g., refined microstructures, extended solid solubilities and reduced segregation). Economic benefits result from process simplification and the elimination of unit operations. Researchers at the Idaho National Engineering Laboratory (INEL) are developing spray-forming technology for producing near-net-shape solids and coatings of a variety of metals, polymers, and composite materials. Results from several spray forming programs are presented to illustrate the range of capabilities of the technique as well as the accompanying technical and economic benefits. Low-carbon steel strip greater than 0.75 mm thick and polymer membranes for gas/gas and liquid/liquid separations that were spray formed are discussed; recent advances in spray forming molds, dies, and other tooling using low-melting-point metals are described

    The Supreme Court As Risk Manager: An Analysis of Skinner

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    Examining a recent case in which the U.S. Supreme Court approved the collection of blood and urine samples from railroad employees, the authors conclude that, in attempting to improve railroad safety, both majority and minority opinions reflected undue emphasis on technical issues and inadequate attention to the intangible social values underlying traditional Constitutional rights to privacy

    L^2 part of the heavy-quark potential from dual QCD and heavy-quark spectroscopy

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    We use the classical approximation to the dual QCD field equations to calculate the term in the heavy-quark potential that is proportional to angular momentum squared. This potential combined with the potentials obtained in our earlier work gives a result which is essentially the dual of the potential acting between a monopole-antimonopole pair carrying Dirac electric dipole moments and rotating in a relativistic superconductor. These potentials are used to fit the masses of the low-lying states of the ccĚ… and bbĚ… systems. The agreement, achieved with only four parameters, two of which are roughly determined in advance, is better than 1%. We also predict the masses of the lightest cbĚ… states

    IDENTIFYING POLICY RELEVANT VARIABLES FOR REDUCING CHILDHOOD MALNUTRITION IN RURAL MALI

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    The paper uses OLS and Logit analyses of household survey data to identify and compare determinants of the health and nutritional status of Malian children living in three distinct agricultural production zones (cotton, millet/sorghum, and irrigated rice). These preliminary results suggest that improvements in health center coverage (e.g., reducing the average distance to a health center from 20 to 10 kilometers) and more diversity in complementary foods after six months of age (two or more different foods during a 24 hour period) have the potential to significantly improve standardized height for age scores. Other factors of importance are mother's incomes, prenatal visits, and parents' standardized heights (reflecting either genetic traits or generations of poor nutrition). Recommendations for reducing Mali's high prevalence of malnutrition include the need to raise awareness of the problem among rural populations. Because rural health workers, local administrators, and parents do not recognize malnutrition as a problem, newly empowered decentralized governments will need some external assistance to get the issue on local agendas and identify potential solutions.Food Consumption/Nutrition/Food Safety,

    A hybrid perturbation Galerkin technique with applications to slender body theory

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    A two step hybrid perturbation-Galerkin method to solve a variety of applied mathematics problems which involve a small parameter is presented. The method consists of: (1) the use of a regular or singular perturbation method to determine the asymptotic expansion of the solution in terms of the small parameter; (2) construction of an approximate solution in the form of a sum of the perturbation coefficient functions multiplied by (unknown) amplitudes (gauge functions); and (3) the use of the classical Bubnov-Galerkin method to determine these amplitudes. This hybrid method has the potential of overcoming some of the drawbacks of the perturbation method and the Bubnov-Galerkin method when they are applied by themselves, while combining some of the good features of both. The proposed method is applied to some singular perturbation problems in slender body theory. The results obtained from the hybrid method are compared with approximate solutions obtained by other methods, and the degree of applicability of the hybrid method to broader problem areas is discussed
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