425 research outputs found

    Photovoltaic module on-orbit assembly for Space Station Freedom

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    One of the elements of the Space Station Freedom power system is the Photovoltaic (PV) module. These modules will be assembled on-orbit during the assembly phase of the program. These modules will be assembled either from the shuttle orbiter or from the Mobile Servicing Center (MSC). The different types of assembly operations that will be used to assemble PV Modules are described

    .NET as a Teaching Tool: Working Paper Series--03-06

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    In the introductory business programming courses, the BASIC programming language was used for many years followed by Visual Basic more recently. In the intermediate and advanced business programming courses COBOL has been the language used for decades, but it has been replaced by Java more recently. This has come with the benefit of the use of objects, but has also come with the costs of a more awkward Graphical User Interface, and more cumbersome data file management than with COBOL. The use of .NET as a teaching tool solves this problem. The shift from VB to VB.NET in the introductory programming courses is a natural one, and the use of C# in the intermediate programming courses addresses the unwieldy nature of data file management in Java, but retains the benefits of object-orientation. The Graphical User Interface available in Visual Basic is retained in VB.NET, which is available for all languages used within .NET, including C#. The .NET development environment offers a seamless development environment for both introductory and intermediate programming courses

    Applied Force and sEMG Muscle Activity Required To Operate Pistol Grip Control in an Electric Utility Aerial Bucket

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    Electric utility line workers report high levels of fatigue in forearm muscles when operating a conventional pistol grip control in aerial buckets. This study measured the applied force and surface electromyographic (sEMG) signals from four upper extremity muscles required to operate the pistol grip control in two tasks. The first task was movement of the pistol grip in six directions (up/down, forward/rearward, clockwise/counter-clockwise), and the second task was movement of the bucket from its resting position on the truck bed to an overhead conductor on top of a 40 ft tall pole. The force applied to the pistol grip was measured in 14 aerial bucket trucks, and sEMG activity was measured on eight apprentice line workers. The applied force required to move the pistol grip control in the six directions ranged from 12 to 15 lb. The sEMG activity in the extensor digitorum communis (EDC) forearm muscle was approximately twice as great or more than the other three muscles (flexor digitorum superficialis, triceps, and biceps). Line workers exerted 14 to 30% MVCEMG to move the pistol grip in the six directions. Average %MVCEMG of the EDC to move the bucket from the truck platform to an overhead line ranged from 26 to 30% across the four phases of the task. The sEMG findings from this study provide physiologic evidence to support the anecdotal reports of muscle fatigue from line workers after using the pistol grip control for repeated, long durations

    Weed Control in Corn

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    Weeds are tough competitors with all crops. And the corn years of your rotation provide as good an opportunity as you\u27ll get to really kill weeds

    A Killer for Weeds in Soybeans

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    Timely use of the rotary hoe is an effective killer for weeds in soybeams. In this article, three Iowa State College scientists report directly to you on their tests comparing different weed-control methods

    The Gas Transfer through Polar Sea Ice Experiment: Insights into the Rates and Pathways that Determine Geochemical Fluxes

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    Sea ice is a defining feature of the polar marine environment. It is a critical domain for marine biota and it regulates ocean-atmosphere exchange, including the exchange of greenhouse gases such as CO2 and CH4. In this study, we determined the rates and pathways that govern gas transport through a mixed sea ice cover. N2O, SF6, 3He, 4He, and Ne were used as gas tracers of the exchange processes that take place at the ice-water and air-water interfaces in a laboratory sea ice experiment. Observation of the changes in gas concentrations during freezing revealed that He is indeed more soluble in ice than in water; Ne is less soluble in ice, and the larger gases (N2O and SF6) are mostly excluded during the freezing process. Model estimates of gas diffusion through ice were calibrated using measurements of bulk gas content in ice cores, yielding gas transfer velocity through ice (kice) of ∼5 × 10−4 m d−1. In comparison, the effective air-sea gas transfer velocities (keff) ranged up to 0.33 m d−1 providing further evidence that very little mixed-layer ventilation takes place via gas diffusion through columnar sea ice. However, this ventilation is distinct from air-ice gas fluxes driven by sea ice biogeochemistry. The magnitude of keff showed a clear increasing trend with wind speed and current velocity beneath the ice, as well as the combination of the two. This result indicates that gas transfer cannot be uniquely predicted by wind speed alone in the presence of sea ice

    Intraoperative Fluid Management a Modifiable Risk Factor for Surgical Quality - Improving Standardized Practice.

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    We aimed to determine a safe zone of intraoperative fluid management associated with the lowest postoperative complication rates without increased acute kidney injury (AKI) risk for elective colorectal surgery patients. Elective colorectal surgeries between 2018 and 2020 were included. Unadjusted odds ratios for postoperative ileus, prolonged length of stay (LOS), and AKI were plotted against the rate of intraoperative ringer's lactate (RL) infusion (mL/kg/h) and total intraoperative volume. Binary logistic regression analysis, including fluid volumes as a confounder, was used to identify risk factors for postoperative complications. A total of 2,900 patients were identified. Of them, 503 (17.3%) patients had ileus, 772 (26.6%) patients had prolonged LOS, and 240 (8.3%) patients had AKI. The intraoperative fluid resuscitation rate (mg/kg/h) was less impactful on postoperative ileus, LOS, and AKI than the total amount of intraoperative fluid. A total fluid administration range between 300 mL and 2.7 L was associated with the lowest complication rate. Total intraoperative RL ≥2.7 L was independently associated with a higher risk of ileus (adjusted OR 1.465;95% CI 1.154-1.858) and prolonged LOS (adjusted OR 1.300;95% CI 1.047-1.613), but not AKI. Intraoperative RL≤300 ml was not associated with an increased risk of AKI. Total intraoperative RL≥2.7L was independently associated with postoperative ileus and prolonged LOS in elective colorectal surgery patients. A new potential standard for intraoperative fluids will require anesthesia case planning (complexity and duration) to ensure total fluid volume meets this new opportunity to improve care
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