2,907 research outputs found

    Design and performance of controlled-diffusion stator compared with original double-circular-arc stator

    Get PDF
    The capabilities of two stators, one with controlled-diffusion (CD) blade sections and one with double-circular-arc (DCA) blade sections, were compared. A CD stator was designed and tested that had the same chord length but half the blades of the DCA stator. The same fan rotor (tip speed, 429 m/sec; pressure ratio, 1.65) was used with each stator row. The design and analysis system is briefly described. The overall stage and rotor performances with each stator are compared, as are selected blade element data. The minimum overall efficiency decrement across the stator was approximately 1 percentage point greater with the CD balde sections than with the DCA blade sections

    Experimental Evaluation of Turning Vane Designs for High-speed and Coupled Fan-drive Corners of 0.1-scale Model of NASA Lewis Research Center's Proposed Altitude Wind Tunnel

    Get PDF
    Two turning vane designs were experimentally evaluated for the fan-drive corner (corner 2) coupled to an upstream diffuser and the high-speed corner (corner 1) of the 0.1 scale model of NASA Lewis Research Center's proposed Altitude Wind Tunnel. For corner 2 both a controlled-diffusion vane design (vane A4) and a circular-arc vane design (vane B) were studied. The corner 2 total pressure loss coefficient was about 0.12 with either vane design. This was about 25 percent less loss than when corner 2 was tested alone. Although the vane A4 design has the advantage of 20 percent fewer vanes than the vane B design, its vane shape is more complex. The effects of simulated inlet flow distortion on the overall losses for corner 1 or 2 were small

    Experimental evaluation of corner turning vanes

    Get PDF
    Two types of turning vane airfoils (a controlled-diffusion shape and a circular arc shape) have been evaluated in the high-speed and fan-drive corners of a 0.1-scale model of NASA Lewis Research Center's proposed Altitude Wind Tunnel. The high-speed corner was evaluated with and without a simulated engine exhaust removal scoop. The fan-drive corner was evaluated with and without the high-speed corner. Flow surveys of pressure and flow angle were taken for both the corners and the vanes to determine their respective losses. The two-dimensional vane losses were low; however, the overall corner losses were higher because three-dimensional flow was generated by the complex geometry resulting from the turning vanes intersecting the end wall. The three-dimensional effects were especially pronounced in the outer region of the circular corner

    Detailed flow surveys of turning vanes designed for a 0.1-scale model of NASA Lewis Research Center's proposed altitude wind tunnel

    Get PDF
    Detailed flow surveys downstream of the corner turning vanes and downstream of the fan inlet guide vanes have been obtained in a 0.1-scale model of the NASA Lewis Research Center's proposed Altitude Wind Tunnel. Two turning vane designs were evaluated in both corners 1 and 2 (the corners between the test section and the drive fan). Vane A was a controlled-diffusion airfoil and vane B was a circular-arc airfoil. At given flows the turning vane wakes were surveyed to determine the vane pressure losses. For both corners the vane A turning vane configuration gave lower losses than the vane B configuration in the regions where the flow regime should be representative of two-dimensional flow. For both vane sets the vane loss coefficient increased rapidly near the walls

    Wind tunnel turning vanes of modern design

    Get PDF
    Rehabilitation of the Altitude Wind Tunnel includes the need for new corner turning vanes to match its upgraded performance. The design and experimental performance results from a 0.1-full scale model of the highest speed corner (M = 0.35) are presented and discussed along with some two dimensional inviscid analyses of two vaned corners. With a vane designed by an inverse two dimensional technique, the overall corner loss was about 12% of the inlet dynamic pressure of which about 4% was caused by vane skin friction. Comparable values with a conventionally designed circular arc vane were about 14% overall with about 7% due to skin friction

    The co-development of friends’ delinquency with adolescents’ delinquency and short-term mindsets:The moderating role of co-offending

    Get PDF
    The companions in crime hypothesis suggests that co-offending moderates the link between peer delinquency and adolescent delinquency. However, this hypothesis has rarely been investigated longitudinally. Hence, this study investigated the co-development of friends’ delinquency and adolescents’ delinquency, as well as the co-development of friends’ delinquency and short-term mindsets (impulsivity and lack of school future orientation). Whether this co-development is stronger when adolescents engage in co-offending was also investigated. Three data waves with two year lags from an ethnically-diverse adolescent sample (at wave 1: N = 1365; 48.6% female; M(age) = 13.67; age range = 12.33–15.09 years) in Switzerland were used. The results from parallel process latent growth modeling showed that the co-development between friends’ delinquency and adolescents’ delinquency was stronger when adolescents engaged in co-offending. Thus co-offending likely provides direct access to a setting in which adolescents continue to model the delinquency they learned with their peers

    Insluiten Ă©n uitsluiten?: over het morele belang van resocialisatie van gedetineerden in Nederland

    Get PDF
    De voorbereiding van gedetineerden op de terugkeer in de maatschappij wordt in de praktijk resocialisatie genoemd. In 1953 werd in de Beginselenwet Gevangeniswezen opgenomen dat de tenuitvoerlegging van straffen hier mede dienstbaar aan moet zijn. Het ideaal en de praktijk van resocialisatie zijn echter in de loop der jaren onder druk komen te staan. De verzakelijkingtendens en bezuinigingen bij overheidsinstellingen, selectiviteit van gedetineerden bij de toekenning van voorzieningen gericht op resocialisatie en de roep om strenger straffen zijn hier voorbeelden van. De aandacht in beleidsnota’s is tegenwoordig voornamelijk gericht op instrumentele doelstellingen zoals effectiviteit en het verminderen van recidivecijfers. Een aantal morele waarden komt daarmee in het geding. Een voorstel wordt gedaan om de aandacht bij resocialisatie te richten op het herstellen van de band tussen gedetineerden en de gemeenschap en – vanuit de humanistiek – om existentiële leerprocessen en horizontale communicatie over morele verantwoordelijkheid te bevorderen. Op deze wijze kan opnieuw vormgegeven worden aan de intrinsieke doelstellingen van resocialisatie

    Can a supported self-management program for COPD upon hospital discharge reduce readmissions? A randomized controlled trial

    Get PDF
    Introduction: Patients with COPD experience exacerbations that may require hospitalization. Patients do not always feel supported upon discharge and frequently get readmitted. A Self-management Program of Activity, Coping, and Education for COPD (SPACE for COPD), a brief self-management program, may help address this issue. Objective: To investigate if SPACE for COPD employed upon hospital discharge would reduce readmission rates at 3 months, compared with usual care. Methods: This is a prospective, single-blinded, two-center trial (ISRCTN84599369) with participants admitted for an exacerbation, randomized to usual care or SPACE for COPD. Measures, including health-related quality of life and exercise capacity, were taken at baseline (hospital discharge) and at 3 months. The primary outcome measure was respiratory readmission at 3 months. Results: Seventy-eight patients were recruited (n=39 to both groups). No differences were found in readmission rates or mortality at 3 months between the groups. Ten control patients were readmitted within 30 days compared to five patients in the intervention group (P>0.05). Both groups significantly improved their exercise tolerance and Chronic Respiratory Questionnaire (CRQ-SR) results, with between-group differences approaching statistical significance for CRQ-dyspnea and CRQ-emotion, in favor of the intervention. The “Ready for Home” survey revealed that patients receiving the intervention reported feeling better able to arrange their life to cope with COPD, knew when to seek help about feeling unwell, and more often took their medications as prescribed, compared to usual care (P<0.05). Conclusion: SPACE for COPD did not reduce readmission rates at 3 months above that of usual care. However, encouraging results were seen in secondary outcomes for those receiving the intervention. Importantly, SPACE for COPD appears to be safe and may help prevent readmission with 30 days
    • …
    corecore