3,138 research outputs found

    Comparison of turbojet-engine altitude performance characteristics and ignition limits with MIL-F-5624A fuel, grades JP-3 and JP-4

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    The performance of MIL-F-5624A fuels, grades JP-3 and JP-4, was investigated in an axial-flow turbojet engine over a range of altitude conditions of 10,000 to 55,000 feet. Examination of the fuel flow, combustion efficiency, and net thrust specific fuel consumption showed the grade JP-4 fuel to be slightly inferior to the grade JP-3 fuel, although the altitude ignition limits were essentially equal for the two fuels over a range of flight Mach numbers and fuel-inlet temperatures

    New Clinical Faculty Training Program: Transforming Practicing Dentists into Part-Time Dental Faculty Members

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    At Indiana University School of Dentistry, a New Clinical Faculty Training (NCFT) program was created with the primary goals of informing new part-time faculty members of clinical policies and assessment guidelines and thus developing qualified and satisfied faculty members. The aim of this study was to determine if participation in the training program improved the participants’ satisfaction and competence in comparison to their colleagues who did not participate in the program. Two cohorts were compared: a control group of part-time faculty members who did not receive formal training when they were hired (n=21; response rate 58.3%); and the intervention group, who had participated in the NCFT program (n=12; response rate 80%). A survey of faculty members in the control group gathered information on their experiences when initially hired, and a pretest was administered to measure their knowledge of clinical policies. After the control group was given an overview of the program, their feedback was collected through post surveys, and a posttest identical to the pretest was given that found statistically significant increases on questions one (p=0.003) and four (p=0.025). In February 2014, 15 new faculty members participated in the pilot implementation of the NCFT program. Of those 15, 12 (the intervention group) completed follow-up surveys identical to the pre survey used with the control group. Statistically significant differences were found for the factors clinical teaching (p=0.005) and assessment training (p=0.008) with better responses for the NCFT group. These results suggest that participation in the program was associated with improved clinical teaching knowledge and job satisfaction

    Nonlinear Soil Response in the Near-Field of a Vibrator Truck: Application to Land Seismic Surveys

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    The nonlinear behavior of soils can significantly modify the wavelet radiated from vibrator trucks. In this paper, we describe a field experiment designed to measure the nonlinear response of a natural soil formation in the near-field of a vibrator truck. A 267-kN (30-ton) vibrator truck performed a step-sweep through a set of 201 discrete frequencies from 50-Hz to 10-Hz, which was repeated at 11 increasing source amplitudes. Steady-state amplitude spectra for the source output measured on the vibrator truck are significantly different than amplitude spectra for receivers located immediately adjacent to the vibrator truck. Spectral ratios between the source and adjacent receivers show a systematic decrease in peak frequency as the source amplitude is increased. Near-field measurements from vibrator trucks provide a more accurate measurement of the source wavelet that includes soil nonlinearity, and may ultimately lead to a method for optimizing the transmission of energy through an arbitrary soil formation.University of California, Los Angeles. Institute of Geophysics and Planetary PhysicsMassachusetts Institute of Technology. Earth Resources Laborator

    Nitrate pharmacokinetics: taking note of the difference

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    Copyright © 2015 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Nitric Oxide: Biology and Chemistry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Nitric Oxide: Biology and Chemistry (2015), DOI: 10.1016/j.niox.2015.04.006It is now recognised that administration of oral nitrate (NO3(-)), in its various forms, increases the level of nitric oxide (NO) metabolites in the circulation of humans. Its application to modulate physiology and alleviate cardiovascular dysfunction in some patients is now recorded and shows particular promise in hypertension, in modifying platelet activation/aggregation, and in conditions where tissue ischemia prevails. The potential of oral NO3(-) to modify exercise/performance via elevation of plasma nitrite concentration ([NO2(-)]) has been applied across a range of human test systems. Herein we discuss how the choice of NO3(-) source, route of administration and resulting pharmacokinetics might influence the outcome of physiological measures and potentially contribute to discrepancies in performance trials. There are but a few examples of detailed pharmacokinetic data on which the majority of researchers base their test protocols in different cohorts/settings. We compare and contrast the results of key publications with the aim of highlighting a consensus of our current understanding and critical considerations for those entering the field

    ‘Extra hands’ or the ‘icing on the cake’?:The boundaries of the volunteer role in formal care settings in England

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    The adult social care sector in England has been encouraged to increase the role of volunteers in service delivery. To understand the volunteer role in care delivery and its impact upon paid care work, we undertook 94 qualitative interviews in seven care settings for older people in England. While the boundaries between care worker and volunteer were clearly established in some organisations, they were more indistinguishable in others. We discuss how both clear and murky boundary making, especially regarding ‘emotional’ and ‘bodily’ aspects of care, can contribute towards paid care work’s invisibility, lack of recognition and poor remuneration

    The contribution of volunteers in social care services for older people

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    Faced with unprecedented challenges, the adult social care sector in England has seen increasing attention given to the potential of volunteers to contribute to service provision. This article reports the findings of a qualitative study that explored the contribution made by volunteers to social care services for older people. The article draws attention to the difficulties associated with recruiting and training volunteers to work in the sector, particularly during a period of reduced public expenditure, which is putting the sector under strain. Given the challenges faced, the article considers whether it is appropriate to involve volunteers in care work
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