1,455 research outputs found

    Interferometric data for a shock-wave/boundary-layer interaction

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    An experimental study of the axisymmetric shock-wave / boundary-layer strong interaction flow generated in the vicinity of a cylinder-cone intersection was conducted. The study data are useful in the documentation and understanding of compressible turbulent strong interaction flows, and are part of a more general effort to improve turbulence modeling for compressible two- and three-dimensional strong viscous/inviscid interactions. The nominal free stream Mach number was 2.85. Tunnel total pressures of 1.7 and 3.4 atm provided Reynolds number values of 18 x 10(6) and 36 x 10(6) based on model length. Three cone angles were studied giving negligible, incipient, and large scale flow separation. The initial cylinder boundary layer upstream of the interaction had a thickness of 1.0 cm. The subsonic layer of the cylinder boundary layer was quite thin, and in all cases, the shock wave penetrated a significant portion of the boundary layer. Owing to the thickness of the cylinder boundary layer, considerable structural detail was resolved for the three shock-wave / boundary-layer interaction cases considered. The primary emphasis was on the application of the holographic interferometry technique. The density field was deduced from an interferometric analysis based on the Able transform. Supporting data were obtained using a 2-D laser velocimeter, as well as mean wall pressure and oil flow measurements. The attached flow case was observed to be steady, while the separated cases exhibited shock unsteadiness. Comparisons with Navier-Stokes computations using a two-equation turbulence model are presented

    Capital Budgeting for Small Businesses: An Appropriate Modification of Net Present Value

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    This paper sets forth a capital budgeting technique that is both theoretically correct and sensitive to the special financing needs of the small business. This technique involves evaluating cash flows and determining if they are sufficient to meet the loan payment schedule. A sufficient amount of cash flow must remain after debt obligations are met to compensate the equity investment. Net operating cash flows are discounted at the cost of equity while the tax shield from interest and depreciation is discounted at the cost of debt

    A Proposed Capital Budgeting Technique For Liquidity Constrained Small Businesses

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    Although the ad vantages of capital budgeting models using discounted cash flaws are well known, small businesses continue to rely on non-discounted techniques in making capital budgeting decisions. This paper analyzes the financial environment in which small businesses operate that makes traditional capital budgeting models inappropriate. A capital budgeting technique is developed that is sensitive to the needs of small businesses and also meets the three-fold criteria for capital budgeting methods.

    Assessment of cockpit interface concepts for data link retrofit

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    The problem is examined of retrofitting older generation aircraft with data link capability. The approach taken analyzes requirements for the cockpit interface, based on review of prior research and opinions obtained from subject matter experts. With this background, essential functions and constraints for a retrofit installation are defined. After an assessment of the technology available to meet the functions and constraints, candidate design concepts are developed. The most promising design concept is described in detail. Finally, needs for further research and development are identified

    The Unintended Effects of AACSB\u27s 2003 Accreditation Standards

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    The AACSB recently adopted new accreditation guidelines that are less restrictive regarding what constitutes qualified faculty for accreditation purposes. The new standards are less restrictive, with less emphasis on a terminal degree and more on faculty being fully participating. However, the new standard may have a detrimental effect on the quality of collegiate business education. It may also reduce the standing and prestige of business schools within the university community. Finally, it may reduce the value of AACSB accreditation

    Detection limits of organic compounds achievable with intense, short-pulse lasers

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    Many organic molecules have strong absorption bands which can be accessed by ultraviolet short pulse lasers to produce efficient ionization. This resonant multiphoton ionization scheme has already been exploited as an ionization source in time-of-flight mass spectrometers used for environmental trace analysis. In the present work we quantify the ultimate potential of this technique by measuring absolute ion yields produced from the interaction of 267 nm femtosecond laser pulses with the organic molecules indole and toluene, and gases Xe, N2 and O2. Using multiphoton ionization cross sections extracted from these results, we show that the laser pulse parameters required for real-time detection of aromatic molecules at concentrations of one part per trillion in air and a limit of detection of a few attomoles are achievable with presently available commercial laser systems. The potential applications for the analysis of human breath, blood and tissue samples are discussed

    Management of Children With Chronic Wet Cough and Protracted Bacterial Bronchitis CHEST Guideline and Expert Panel Report

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    BACKGROUND: Wet or productive cough is common in children with chronic cough. We formulated recommendations based on systematic reviews related to the management of chronic wet cough in children (aged METHODS: We used the CHEST expert cough panel\u27s protocol for systematic reviews and the American College of Chest Physicians (CHEST) methodologic guidelines and GRADE framework (the Grading of Recommendations Assessment, Development and Evaluation). Data from the systematic reviews in conjunction with patients\u27 values and preferences and the clinical context were used to form recommendations. Delphi methodology was used to obtain consensus for the recommendations/suggestions made. RESULTS: Combining data from the systematic reviews, we found high-quality evidence in children aged 4 weeks\u27 duration) wet/productive cough that using appropriate antibiotics improves cough resolution, and further investigations (eg, flexible bronchoscopy, chest CT scans, immunity tests) should be undertaken when specific cough pointers (eg, digital clubbing) are present. When the wet cough does not improve following 4 weeks of antibiotic treatment, there is moderate-quality evidence that further investigations should be considered to look for an underlying disease. New recommendations include the recognition of the clinical diagnostic entity of protracted bacterial bronchitis. CONCLUSIONS: Compared with the 2006 Cough Guidelines, there is now high-quality evidence for some, but not all, aspects of the management of chronic wet cough in specialist settings. However, further studies (particularly in primary health) are required

    Reflective self-attention: A more stable predictor of connection to nature than mindful attention.

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    There is much to be gained from understanding the individual differences that predict our connection to nature, as those that are more connected tend to be more caring towards the environment and benefit from better well-being. Study 1 (n=137) found that reflective self-attention and mindful attention significantly predicted connection to nature, while anxious self-attention had a borderline significant negative association. With the introduction of personality measures, study 2 (n=161) found that reflective self-attention and openness had a stronger relationship to nature connection than mindful attention. Study 3 (n=99) found reflective self-attention, rather than mindful attention, to be associated with an increase in connection to nature. A pre-reflective and intentional self-attention account of nature connectedness is proposed with intentional self-reflection being a stronger factor than mindful attention
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