11,700 research outputs found

    Corn/soybean decision logic: Improvements and new crops

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    There are no author-identified significant results in this report

    SMDS measurements and modeling to predict performance

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    The authors describe a performance study of a trial switched multimegabit data service (SMDS) link (intended for inter-LAN connection) from the perspective of customers evaluating the feasibility of the link for some target applications. The goals were to take all measurements on the customer premises and to develop a methodology general enough to be used by customers to evaluate the link. The authors measured a lightly loaded system and developed a model of the SMDS connection suitable for evaluating applications via analysis or simulation. They document their methodology and present the SMDS connection delay values as well as a likely breakdown of the constituents of that delay. They used these data to create a simulation model and to simulate a simple application. In the trial configuration, where geographical distances were small, SMDS network delay was one of the notable components of end-to-end delay in the SMDS connection. However, for most packets, throughput is limited by the T1 capacity for transmitting SMDS cells, not by the SMDS network capacity

    A comparison of radiation damage in liner ICs from cobalt-60 gamma rays and 2.2-MeV electrons

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    The total ionizing dose response of fourteen IC types from eight manufacturers was measured using Co-60 gamma rays and 2.2-MeV electrons for exposure levels of 100 to 20,000 Gy(Si). Key parameter measurements were made and compared for each device type. The data show that a Co-60 source is not a suitable simulation source for some systems because of the generally more damaging nature of electrons as well as the unpredictable nature of the individual device response to the two types of radiations used here

    Method and apparatus for power plant simulation and optimization

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    A system for simulating and optimizing a powerhouse designed to furnish electrical power to a process plant which incorporates a plurality of units for simulating operation of the individual components of the powerhouse, and for calculating the cost of operation of the system as a whole, including the cost of fuel for the powerhouse components and the cost of purchased power needed to satisfy the power demand of the process plant beyond the capacity of the powerhouse. An adaptive search routine varies all of the operative parameters of the powerhouse, on a random basis, and repeats the simulation in order to identify a combination of parameters which represents a lower cost solution. The range of random variation is reduced, as lower cost solutions are not found within a given number of repetitions, in order to identify a precise convergence on the optimum solution. The procedure may be restarted, and repeated many times, with the range of variation each time initially at maximum, in order to insure the identification of the global optimum

    Workers Without Health Insurance: Who Are They and How Can Policy Reach Them?

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    Offers a detailed picture of the 16 million uninsured working population in the U.S., identifies potential causes and effects, and examines the policy implications and options

    Electron-Phonon Interactions in C28_{28}-derived Molecular Solids

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    We present {\it ab initio} density-functional calculations of molecular solids formed from C28_{28}-derived closed-shell fullerenes. Solid C28_{28}H4_4 is found to bind weakly and exhibits many of the electronic structure features of solid C60_{60} with an enhanced electron-phonon interaction potential. We show that chemical doping of this structure is feasible, albeit more restrictive than its C60_{60} counterpart, with an estimated superconducting transition temperature exceeding those of the alkali-doped C60_{60} solids.Comment: Lower quality postscript file for Figure 1 is used in the manuscript in order to meet submission quota for pre-print server. Higher quality postscript file available from author: [email protected] This article has been updated to reflect changes incorporated during the peer review process. It is published in PRB 70, 140504(R) 200

    A study of the social and physical environment in catering kitchens and the role of the chef in promoting positive health and safety behaviour

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    This is the account of a mixed method study of chefs and their kitchens in order to identify the nature of their workplace and how this affects their ability to manage health and safety in the kitchen. It included extended periods of observation, monitoring of physical parameters, analysis of records of reported accidents, and a series of reflexive interviews. The findings were integrated and then fed back in a smaller number of second interviews in order to test whether the findings fitted in with the chefs' understanding of their world. Major factors identified included survival in a market environment, the status of the chef (and the kitchen) within organisations, marked autocracy of chefs, and an increasing tempo building up to service time with commensurate heat, noise, and activity. In particular during the crescendo, a threshold shift in risk tolerance was identified. The factors, their interplay, and their implications for health and safety in the catering kitchen are discussed

    Evaluation of the Loss of Uniaxial Compressive Strength of Sandstones Due to Moisture

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    The reduction in uniaxial compressive strength (UCS) was investigated for sandstones under various moisture levels. Thirty-four UK Darney sandstone samples were tested under six different moisture conditions. The time-dependent moisture gain and loss were also evaluated. For 77 sandstones identified in the literature, the loss of UCS between oven-dry and saturated conditions was up to 45%, with an average of 20%. For Darney stone, the average loss of UCS was around 20%, with UCS around 72 N/mm2 when oven-dry and 58 N/mm2 when fully saturated. During saturation, significant loss of UCS occurred soon after exposure to water with 80% of UCS being lost within the first 2.5–6 hours. For Darney stone 50% of UCS was lost at air-dry conditions. Results from the 78 sandstone types were compared with the equivalent compressive strength defined by BS EN 772–1:2011 for oven-dry, air-dry, and saturated conditions. The estimated values by BS EN 772–1:2011 for dry and saturated UCS agreed well with the available test data and indicated a lower-bound solution. For immersed conditions, BS EN 772–1:2011, however, overestimates the reduction in UCS for a large number of samples and provides an average, instead of a lower-bound solution
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