59,198 research outputs found

    Proof-of-concept engineering workflow demonstrator

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    When Microsoft needed a proof-of-concept implementation of bespoke engineering workflow software for their customer, BAE Systems, it called on the software engineering skills and experience of the Microsoft Institute for High Performance Computing. BAE Systems was looking into converting their in-house SOLAR software suite to run on the MS Compute Cluster Server product with 64-bit MPI support in conjunction with an extended Windows Workflow environment for use by their engineer

    A REGIONAL BAN OF ALACHLOR AND ATRAZINE IN SOUTHEASTERN MINNESOTA: THE ECONOMIC AND ENVIRONMENTAL EFFECTS

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    Crop Production/Industries, Environmental Economics and Policy,

    A laboratory investigation of the variability of cloud reflected radiance fields

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    A method to determine the radiative properties of complex cloud fields was developed. A Cloud field optical simulator (CFOS) was constructed to simulate the interaction of cloud fields with visible radiation. The CFOS was verified by comparing experimental results from it with calculations performed with a Monte Carlo radiative transfer model. A software library was developed to process, reduce, and display CFOS data. The CFSOS was utilized to study the reflected radiane patterns from simulated cloud fields

    Merging White Dwarfs and Thermonuclear Supernovae

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    Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure, and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and our suggestion that these supernovae instead result from mergers of carbon-oxygen white dwarfs, including those that produce sub-Chandrasekhar mass remnants. I then turn to possible observational tests, in particular those that test the absence or presence of electron captures during the burning.Comment: 8 pages, 1 figures, accepted for publication in Phil. Tr. A, proc. of New windows on transients across the Universe, ed. P. O'Brien et al.; v2 includes changes following comments by the 2 referee

    Radiative properties of cirrus clouds inferred from broadband measurements during FIRE

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    It is well known that clouds are significant modulators of weather and climate because of their effects on the radiation field and thus on the energy balance of the earth atmosphere system. As a result, the accurate prediction of weather and climate depends to a significant degree on the accuracy with which cloud radiation interactions can be described. The broadband radiative and microphysical properties of five cirrus cloud systems are reported, as observed from the NCAR Sabreliner during the FIRE first Cirrus IFO, in order to better understand cirrus cloud-radiation interactions. A broadband infrared (BBIR) radiative transfer model is used to deduce BBIR absorption coefficients in order to assess the impact of the cirrus clouds on infrared radiation. The relationships of these absorption coefficients to temperature and microphysical characteristics are explored

    Temperature sensitivity of Eppley broadband radiometers

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    Broadband radiometers manufactured by Eppley Laboratories Inc. are commonly used to measure irradiance from both ground-based and aircraft platforms. Namely, the pyranometer (Model PSP) measures irradiance in the .3 to 3.0 micron spectral region while the pyrgeometer (Model PIR) senses energy in the 4 to 50 micron region. The two instruments have a similar thermopile construction but different filters to achieve the appropriate spectral selection. During the fall of 1986, the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE) commenced with the first cirrus Intensive Field Observation (IFO) conducted in Central Wisconsin. Due to the nature of this field project, pyranometers and pyrgeometers manufactured by Eppley were flown on NCAR's high altitude research aircraft, the Sabreliner. Inherent in the construction of these radiometers is temperature compensation circuitry designed to make the instrument sensitivity nominally constant over a temperature range from -20 to +40 C. Because the Sabreliner flew at high altitudes where temperatures were as cold as -70 C, it was necessary to determine the radiometers relative sensitivity to temperatures below -20 C and apply appropriate corrections to the FIRE radiation data set. A procedure to perform this calibration is outlined. It is meant to serve as a supplement to calibration procedures

    A Morse index theorem for elliptic operators on bounded domains

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    Given a selfadjoint, elliptic operator LL, one would like to know how the spectrum changes as the spatial domain ΩRd\Omega \subset \mathbb{R}^d is deformed. For a family of domains {Ωt}t[a,b]\{\Omega_t\}_{t\in[a,b]} we prove that the Morse index of LL on Ωa\Omega_a differs from the Morse index of LL on Ωb\Omega_b by the Maslov index of a path of Lagrangian subspaces on the boundary of Ω\Omega. This is particularly useful when Ωa\Omega_a is a domain for which the Morse index is known, e.g. a region with very small volume. Then the Maslov index computes the difference of Morse indices for the "original" problem (on Ωb\Omega_b) and the "simplified" problem (on Ωa\Omega_a). This generalizes previous multi-dimensional Morse index theorems that were only available on star-shaped domains or for Dirichlet boundary conditions. We also discuss how one can compute the Maslov index using crossing forms, and present some applications to the spectral theory of Dirichlet and Neumann boundary value problems.Comment: 21 pages; weaker regularity assumptions than in the first versio

    New method for critical failure prediction of complex systems

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    Rigorous analytical technique, called criticality determination methodology /or CD technique/ determines the probability that a given complex system will successfully achieve stated objectives. The CD technique identifies critical elements of the system by a failure mode and effects analysis
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