639 research outputs found

    Deflation of Eigenvalues for Iterative Methods in Lattice QCD

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    Work on generalizing the deflated, restarted GMRES algorithm, useful in lattice studies using stochastic noise methods, is reported. We first show how the multi-mass extension of deflated GMRES can be implemented. We then give a deflated GMRES method that can be used on multiple right-hand sides of Ax=bAx=b in an efficient manner. We also discuss and give numerical results on the possibilty of combining deflated GMRES for the first right hand side with a deflated BiCGStab algorithm for the subsequent right hand sides.Comment: Lattice2003(machine

    Farming Systems in the Pastoral Zone of NSW: An Economic Analysis

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    A ‘broad brush’ picture of farming in the pastoral zone of NSW is presented in this report. The pastoral zone of NSW is characterised by wide variations in climatic conditions, soil type and vegetation species. Hence representative faming system analysis was conducted for three sub-regions - the Upper Darling, the Murray-Darling and Far West. The regions were defined and described in terms of their resources, climate and the nature of agriculture. The main enterprises that farmers choose between were described and whole farm budgets and statements of assets and liabilities for the representative farms were developed. The representative farm models were used to compare traditional Merino based sheep enterprises with alternative sheep enterprises where meat was an important source of income. We found that the farming systems that have evolved in these areas are well suited to their respective environments and that the economic incentives to switch to more meat focussed sheep enterprises were not strong.Western Division, farming systems, economic, analysis, New South Wales, Farm Management, Land Economics/Use, Livestock Production/Industries, Production Economics, Research and Development/Tech Change/Emerging Technologies, Q160,

    Wrapping Transition and Wrapping-Mediated Interactions for Discrete Binding along an Elastic Filament: An Exact Solution

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    The wrapping equilibria of one and two adsorbing cylinders are studied along a semi-flexible filament (polymer) due to the interplay between elastic rigidity and short-range adhesive energy between the cylinder and the filament. We show that statistical mechanics of the system can be solved exactly using a path integral formalism which gives access to the full effect of thermal fluctuations, going thus beyond the usual Gaussian approximations which take into account only the contributions from the minimal energy configuration and small fluctuations about this minimal energy solution. We obtain the free energy of the wrapping-unwrapping transition of the filament around the cylinders as well as the effective interaction between two wrapped cylinders due to thermal fluctuations of the elastic filament. A change of entropy due to wrapping of the filament around the adsorbing cylinders as they move closer together is identified as an additional source of interactions between them. Such entropic wrapping effects should be distinguished from the usual entropic configuration effects in semi-flexible polymers. Our results may be applicable to the problem of adsorption of proteins as well as synthetic nano-particles on semi-flexible polymers such as DNA.Comment: 24 pages, 12 figure

    PHASE I ASSESSMENT OF GUARDRAIL LENGTH-OF-NEED

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    Report No. TRP-03-284-1

    ROADSIDE GRADING GUIDANCE - PHASE I

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    Provisions for the design of roadside foreslopes are not readily available. As a result, engineering judgment is often employed. Unfortunately, this can lead to inconsistent designs, where, inevitably, some designs will be too costly and other designs will be too dangerous. Therefore guidance has been compiled to lend consistency to the design of these foreslopes while maintaining the most economical and safe design. This guidance was prepared after conducting a benefit-cost analysis using the Roadside Safety Analysis Program (RSAP). A large test matrix was developed in an attempt to simulate the most possible scenarios, leaving interpolation to a minimum. However, before the analysis could be run, the severity indices associated with foreslopes needed to be updated to accurately reflect vehicle damage and injury levels caused during an encroachment occurring at an average impact speed. Current indices are overestimated because they were based on a survey given out to highway safety officials who were most likely biased toward high-speed accidents. More data is being collected and will be added to the results of this report in phase two. To update the severity indices, accident data from the State of Ohio was analyzed using a program called Global Mapper, which allowed the user to measure topographical features, such as foreslopes, heights, and offsets. A method to account for underreported accidents on flat slopes is presented as well. Finally, equations for determining accident cost as a function of the traffic volume are given in conjunction with examples that demonstrate the use of these equations

    An evolvable space telescope for future astronomical missions

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    Astronomical flagship missions after JWST will require affordable space telescopes and science instruments. Innovative spacecraft-electro-opto-mechanical system architectures matched to the science requirements are needed for observations for exoplanet characterization, cosmology, dark energy, galactic evolution formation of stars and planets, and many other research areas. The needs and requirements to perform this science will continue to drive us toward larger and larger apertures. Recent technology developments in precision station keeping of spacecraft, interplanetary transfer orbits, wavefront/sensing and control, laser engineering, macroscopic application of nano-technology, lossless optical designs, deployed structures, thermal management, interferometry, detectors and signal processing enable innovative telescope/system architectures with break-through performance. Unfortunately, NASA’s budget for Astrophysics is unlikely to be able to support the funding required for the 8 m to 16 m telescopes that have been studied as a follow-on to JWST using similar development/assembly approaches without decimating the rest of the Astrophysics Division’s budget. Consequently, we have been examining the feasibility of developing an “Evolvable Space Telescope” that would begin as a 3 to 4 m telescope when placed on orbit and then periodically be augmented with additional mirror segments, structures, and newer instruments to evolve the telescope and achieve the performance of a 16 m or larger space telescope. This paper reviews the approach for such a mission and identifies and discusses candidate architectures

    Studies on Viruses in Water

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    A new procedure for the detection of viral antigens in fecal material was developed. The test is performed by first diluting a fecal sample with phosphate buffered saline to give a liquid consistency. The pH is then adjusted to 8.5-9.0 and the solids are allowed to settle for five minutes. Supernatant fluid from above the fecal sediment is placed on the upper surface of a well of an inverted Immulon microtiter plate and incubated for one hour at 37 degrees C to allow virus to adsorb to the plastic. The Immulon plate is then washed three times with a Tween 20 solution and dried. Adsorbed virus is stained with fluorescein labled antiviral antibody containing Evan\u27s Blue dye. The stained preparations are examined by epi-fluorescence microsopy for the presence of viral aggregates and virus-containing cellular membranes. The test is applied in a continuous water monitoring procedure that can be used to upplement methods in which infectious viruses are isolated from water. In another study a protamine sulfate procedure for concentrating and an immunofluorescent cell procedure for assaying infectious virus (IV, reovirus that is infectious without proteolytic enzyme treatment), and potentially infectious virus (PIV, enzyme enhanceable reovirus) from polluted waters have been developed. The presence of PIV inthe environment had not previously been investigated. In following these procedures, protamine sulfate concentratiosn of 0.005 percent for the first precipitation of the sample, and 0.0025 percent for the second were used. With these protamine concentrations and 0.25 percent fetal bovine serum, IV and PIV are concentrations over 500-fold from river water inoculated with virus. Virus recoveries are between 80 and 100 percent. The IV and PIV fractions are assayed respectively before and after treatment with 200 ug fo chymotrypsin per millileter. When PIV is precipitated from river water, and the precipitate is dissolved and stored at 20 degrees C as a protamine-virus concentrate, only 5 percent of the viral infectivity is lost after 14 days. Therefore, reovirus can be precipitated from water at the sampling site, and only the protamine concentrate needs to be taken to the laboratory to be examined for virus content. When reoviruses are treated with chlorine, PIV is more resistant to inactivation thatn IV, and PIV appears to be at least as resistant to chlorination as poliovirus and coxsackievirus A-2. Granular media filtration systems (i.e., sand, anthracite coal and sand; anthracite coal; sand and garnet) are ineffectual in the removal of the acteriophage MS 2 from water when used as in-line direct filters. Batch assays have indicated a 93 percent reduction of MS 2 can occur when polyelectrolytes are added to the water. In addition, alum concentrations of 20, 30, 40, and 50 mg/1 remove 80 to 98 percent of the virus by precipitation. No reduction of MS 2 was observed at alum concentrations from 1 to 10 mg/1

    Cost-Benefit Analysis of Crash Cushion Systems

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    Crash cushions vary in geometry and cost. In this study, crash cushions were categorized in three different categories: redirecting with repair costs greater than 1,000(RGM),redirectingwithrepaircostslessthan1,000 (RGM), redirecting with repair costs less than 1,000 (RLM), and nonredirecting sacrificial (NRS). Typically, RGM systems are less expensive initially, but life-cycle costs are high. RLM systems typically reciprocate this trend. NRS crash cushions (e.g., sand barrels) are generally less expensive but require total replacement after a crash has occurred, which may be impractical at high-traffic volume locations. Due to limited funding, there is often a need to identify the most cost-effective crash cushion category for highway scenarios with different roadway, traffic, and roadside characteristics. This study was commissioned to determine benefit-cost ratios for each crash cushion category in a wide range of roadway and roadside characteristics using the probability-based encroachment tool, Roadside Safety Analysis Program. Only RGM and RLM systems were cost effective for freeways and divided rural arterials, but all three categories competed against the unprotected condition on undivided rural arterials and local roads

    Orion Crew Exploration Vehicle Launch Abort System Guidance and Control Analysis Overview

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    Aborts during the critical ascent flight phase require the design and operation of Orion Crew Exploration Vehicle (CEV) systems to escape from the Crew Launch Vehicle (CLV) and return the crew safely to the Earth. To accomplish this requirement of continuous abort coverage, CEV ascent abort modes are being designed and analyzed to accommodate the velocity, altitude, atmospheric, and vehicle configuration changes that occur during ascent. Aborts from the launch pad to early in the flight of the CLV second stage are performed using the Launch Abort System (LAS). During this type of abort, the LAS Abort Motor is used to pull the Crew Module (CM) safely away from the CLV and Service Module (SM). LAS abort guidance and control studies and design trades are being conducted so that more informed decisions can be made regarding the vehicle abort requirements, design, and operation. This paper presents an overview of the Orion CEV, an overview of the LAS ascent abort mode, and a summary of key LAS abort analysis methods and results

    An evolvable space telescope for future astronomical missions 2015 update

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    In 2014 we presented a concept for an Evolvable Space Telescope (EST) that was assembled on orbit in 3 stages, growing from a 4x12 meter telescope in Stage 1, to a 12-meter filled aperture in Stage 2, and then to a 20-meter filled aperture in Stage 3. Stage 1 is launched as a fully functional telescope and begins gathering science data immediately after checkout on orbit. This observatory is then periodically augmented in space with additional mirror segments, structures, and newer instruments to evolve the telescope over the years to a 20-meter space telescope. In this 2015 update of EST we focus upon three items: 1) a restructured Stage 1 EST with three mirror segments forming an off-axis telescope (half a 12-meter filled aperture); 2) more details on the value and architecture of the prime focus instrument accommodation; and 3) a more in depth discussion of the essential in-space infrastructure, early ground testing and a concept for an International Space Station testbed called MoDEST. In addition to the EST discussions we introduce a different alternative telescope architecture: a Rotating Synthetic Aperture (RSA). This is a rectangular primary mirror that can be rotated to fill the UV-plane. The original concept was developed by Raytheon Space and Airborne Systems for non-astronomical applications. In collaboration with Raytheon we have begun to explore the RSA approach as an astronomical space telescope and have initiated studies of science and cost performance
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