7,901 research outputs found

    Effect of Blade Planform Variation on a Small-Scale Hovering Rotor

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    A hover test was conducted on a small-scale rotor model for three sets of tapered rotor blades and a baseline rectangular planform rotor blade. All configurations had the same airfoils, twist, and thrust-weighted solidity. The tapered blade planforms had taper initiating at 50, 75, and 94 percent of the blade radius with a taper ratio of 3 to 1 for each blade set. The experiment was conducted for a range of thrust coefficients, and the data were compared to the predictions of three hover analysis methods. The data show the 94 percent tapered blade was slightly more efficient at the higher rotor thrust levels. The other tapered planform rotors did not show the expected improvement over the baseline rotor, and all configurations had similar performance for low thrust coefficients. None of the analysis methods correlated well with the experimental data

    Rotor blade aerodynamic design

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    Aerodynamic performance aspects of rotor blade design are presented. Design considerations, aerodynamic constraints and design variables are described

    Tracking and Improving Bedside Procedures Through Standardized Documentation

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    Proposal and Goals: We propose to create a standardized electronic procedure note that will replace all documentation for bedside procedures without sedation. ◦Makes notes legible and easily identified ◦Allows uniform tracking of metrics necessary to identify outcomes from a procedure (blood loss, specimens, post-procedure studies, complications) 2.The procedure note will be created in such a way as to allow specialized procedures to be added over time with minor customization to improve physician/nursing work flows and increase efficiency ◦Allows procedures to be sorted and tracked by type ◦Will be constructed to allow attaching CPT codes to patient charts via documentation 3. We propose using this procedure note to create a running database of all bedside procedures ◦Can be utilized by existing software (Qlik) to query all procedure notes to create large anonymized patient listshttps://jdc.jefferson.edu/patientsafetyposters/1071/thumbnail.jp

    Rhodium/phospholane-phosphite catalysts give unusually high regioselectivity in the enantioselective hydroformylation of vinyl arenes

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    Using the phospholane-phosphite ligand, BOBPHOS, almost perfect regioselectivities and high enantioselectivities (up to 92% ee) are observed in Rh catalysed enantioselective hydroformylation of vinyl arenes. This can be achieved under solvent-free conditions.PostprintPeer reviewe

    Two-dimensional aerodynamic characteristics of the OLS/TAAT airfoil

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    Two flight tests have been conducted that obtained extension pressure data on a modified AH-1G rotor system. These two tests, the Operational Loads Survey (OLS) and the Tip Aerodynamics and Acoustics Test (TAAT) used the same rotor set. In the analysis of these data bases, accurate 2-D airfoil data is invaluable, for not only does it allow comparison studies between 2- and 3-D flow, but also provides accurate tables of the airfoil characteristics for use in comprehensive rotorcraft analysis codes. To provide this 2-D data base, a model of the OLS/TAAT airfoil was tested over a Reynolds number range from 3 x 10 to the 6th to 7 x 10 to the 7th and between Mach numbers of 0.34 to 0.88 in the NASA Langley Research Center's 6- by 28-Inch Transonic Tunnel. The 2-D airfoil data is presented as chordwise pressure coefficient plots, as well as lift, drag, and pitching moment coefficient plots and tables

    Insurgent Labor Activists at Yale, 1968-1971

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    At noon on April 30, 1971, some Yale students began busing their own trays. Others flipped food-filled plates and tables onto the floor. Almost 100 students broke chairs and other furniture.Commons, the main dining hall on campus, became a “slippery, sloshing pigpen,” according to the Yale Daily News. Soon, nearly 300 students flooded Commons, throwing metal trays across the hall while policemen and dining managers watched grimly nearby. “Support the Yale workers,” they chanted, doing all they could to halt Commons’s services. That day, over 1,000 service and maintenance employees at Yale, part of Local 35 of the Federation of University Employees, went on strike. Their leader, Vincent Sirabella, was determined to avoid a repeat of three years earlier, when Yale crushed the union’s walkout in less than a week. New on the job, Sirabella faced his opportunity to demonstrate his concern, toughness, and tactical acumen to Yale and to the workers he represented. Failure would almost certainly entail a spell of pitiful wages and poor working conditions for his workers, as well as ejection from his job. It was up to him to rally his workers against the monolithic, aggressive, superrich institution that was Yale

    Measuring the Efficacy of Leaders to Assess Information and Make Decisions in a Crisis: The C-LEAD Scale

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    Based on literature and expert interviews, we developed the Crisis Leader Efficacy in Assessing and Deciding scale (C-LEAD) to capture the efficacy of leaders to assess information and make decisions in a public health and safety crisis. In Studies 1 and 2, we find that C-LEAD predicts decision-making difficulty and confidence in a crisis better than a measure of general leadership efficacy. In Study 3, C-LEAD predicts greater motivation to lead in a crisis, more crisis leader role-taking, and more accurate performance while in a crisis leader role. These findings support the scale's construct validity and broaden our theoretical understanding of the nature of crisis leader efficacy.

    Effect of blade planform variation on the forward-flight performance of small-scale rotors

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    An investigation was conducted in the Glenn L. Martin Wind Tunnel to determine the effect of blade planform variation on the forward-flight performance of four small-scale rotors. The rotors were 5.417 ft in diameter and differed only in blade planform geometry. The four planforms were: (1) rectangular; (2) 3:1 linear taper starting at 94 percent radius; (3) 3:1 linear taper starting at 75 percent radius; and (4) 3:1 linear taper starting at 50 percent radius. Each planform had a thrust-weighted solidity of 0.098. The investigation included forward-flight simulation at advance ratios from 0.14 to 0.43 for a range of rotor lift and drag coefficients. Among the four rotors, the rectangular rotor required the highest torque for the entire range of rotor drag coefficients attained at advanced ratios greater than 0.14 for rotor lift coefficients C sub L from 0.004 to 0.007. Among the rotors with tapered blades and for C sub L = 0.004 to 0.007, either the 75 percent tapered rotor or the 50 percent tapered rotor required the least amount of torque for the full range of rotor drag coefficients attained at each advance ratio. The performance of the 94 percent tapered rotor was generally between that of the rectangular rotor and the 75 and 50 percent tapered rotors at each advance ratio for this range of rotor lift coefficients

    Measuring the Efficacy of Leaders to Assess Information and Make Decisions in a Crisis: The C-LEAD Scale

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    Based on literature and expert interviews, we developed the Crisis Leader Efficacy in Assessing and Deciding scale (C-LEAD) to capture the efficacy of leaders to assess information and make decisions in a public health and safety crisis. In Studies 1 and 2, we find that C-LEAD predicts decision-making difficulty and confidence in a crisis better than a measure of general leadership efficacy. In Study 3, C-LEAD predicts greater motivation to lead in a crisis, more crisis leader role-taking, and more accurate performance while in a crisis leader role. These findings support the scale’s construct validity and broaden our theoretical understanding of the nature of crisis leader efficacy

    Is England's public health nutrition system in crisis? A qualitative analysis of the capacity to feed all in need during the COVID-19 pandemic

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    Methodology: An exploratory methodology was adopted to examine experiences relating to capability and capacity among formal and informal helpers within the PHN domain. An online survey, mainly open-ended questions, was used to capture experiences over the period 2010 - 2020. A mixed sampling strategy, including snowball and convenience sampling, via social media and social network contact-sharing approaches, was adopted. Data was analysed using an inductive thematic approach. Results: A total of 89 participants representing the PHN system in England were recruited over two months. Three main themes and eight sub-themes were identified. The first reflected unequivocal accounts of the impact of austerity and the inability of PHN services to meet demand for food security. The second articulated capacity and capability issues within the system, with geographical variations in service delivery, and a lack of connectivity between central, local government, and third sector providers. These were attributed to widening nutrition and health inequalities. Participants felt that the government needed to invest more technical and financial resources to support public health nutrition. They also felt that schools could play a larger role at local level, but there was a need for a clear national recovery plan, setting out a comprehensive and fully supported national strategy to eradicate food insecurity in England Conclusions: Further in-depth research is needed to continue to track the impact of recovery strategies on food insecure people and the capacity of the PHN system. Urgent investment in the capacity and coordination of PHN services is needed to support food insecure people in England. The UK could include the ratification of the right to food in national laws, in line with global commitments already agreed to by the UK State Party
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