7,166 research outputs found

    Effect of cooling-hole geometry on aerodynamic performance of a film-cooled turbine vane tested with cold air in a two-dimensional cascade

    Get PDF
    The effect of the orientation and cooling-hole size on turbine-vane aerodynamic losses was evaluated. The contribution of individual vane regions to the overall effect was also investigated. Test configurations were based upon a representative configuration having 45 spanwise rows of holes spaced about the entire vane profile. Nominal hole diameters of 0.0254 and 0.0356 cm and nominal hole orientations of 35 deg, 45 deg, and 55 deg from the local vane surface and 0 deg, 45 deg, and 90 deg from the main-stream flow direction were investigated. Flow conditions and aerodynamic losses were determined by vane-exit surveys of total pressure, static pressure, and flow angle

    Incidence loss for fan turbine rotor blade in two-dimensional cascade

    Get PDF
    The effect of incidence angle on the aerodynamic performance of a fan turbine rotor blade was investigated experimentally in a two dimensional cascade. The test covered a range of incidence angles from -15 deg to 10 deg and exit ideal critical velocity ratios from 0.75 to 0.95. The principal measurements were blade-surface static pressures and cross-channel survey of exit total pressure, static pressure, and flow angle. Flow adjacent to surfaces was examined using a visualization technique. The results of the investigation include blade-surface velocity distribution and overall kinetic energy loss coefficients for the incidence angles and exit velocity ratios tested. The measured losses are compared with those from a reference core turbine rotor blade and also with two common analytical methods of predicting incidence loss

    Changing the ideological roots of prejudice: Longitudinal effects of ethnic intergroup contact on social dominance orientation

    Get PDF
    Social Dominance Orientation (SDO) has been reported to be strongly related to a multitude of intergroup phenomena, but little is known about situational experiences that may influence SDO. Drawing from research on intergroup contact theory, we argue that positive intergroup contact is able to reduce SDO-levels. The results of an intergroup contact intervention study among high school students (Study 1, N=71) demonstrated that SDO-levels were indeed attenuated after the intervention. Furthermore, this intervention effect on SDO was especially pronounced among students reporting a higher quality of contact. A cross-lagged longitudinal survey among adults (Study 2, N=363) extended these findings by demonstrating that positive intergroup contact is able to decrease SDO over time. Moreover, we did not obtain evidence for the idea that people high in SDO would engage less in intergroup contact. These findings indicate that intergroup contact erodes one of the important socio-ideological bases of generalized prejudice and discrimination

    Shoot growth of woody trees and shrubs is predicted by maximum plant height and associated traits

    No full text
    1. The rate of elongation and thickening of individual branches (shoots) varies across plant species. This variation is important for the outcome of competition and other plant-plant interactions. Here we compared rates of shoot growth across 44 species from tropical, warm temperate, and cool temperate forests of eastern Australia.2. Shoot growth rate was found to correlate with a suite of traits including the potential height of the species, xylem-specific conductivity, leaf size, leaf area per xylem cross-section, twig diameter (at 40 cm length), wood density and modulus of elasticity.3. Within this suite of traits, maximum plant height was the clearest correlate of growth rates, explaining 50 to 67% of the variation in growth overall (p p 4. Growth rates were not strongly correlated with leaf nitrogen or leaf mass per unit leaf area.5. Correlations between growth and maximum height arose both across latitude (47%, p p p p < 0.0001), reflecting intrinsic differences across species and sites

    Measurement of salinity distributions in salt‐stratified, double‐diffusive systems by optical deflectometry

    Get PDF
    This is the published version. Copyright © 1986 American Institute of PhysicsReliable salinity measurements in double‐diffusive thermohaline solutions are necessary to understand relevant system behavior. An optical technique, which has previously been used to investigate solutediffusion in isothermal systems, is employed to measure the salinity distribution in a double‐diffusive thermohaline system. The technique is verified by comparison with independent salinity measurements, and its use in a double‐diffusive system reveals detailed salinity distribution information. When used with the shadowgraph method of flow visualization, the salinity measurement technique permits a more quantitative interpretation of the shadowgraphic results

    Stroke impact on mortality and psychologic morbidity within the Childhood Cancer Survivor Study.

    Get PDF
    BackgroundPoor socioeconomic and health-related quality of life (HRQOL) outcomes in survivors of childhood cancer can lead to distress and overall negatively impact the lives of these individuals. The current report has highlighted the impact of stroke and stroke recurrence on mortality, psychological HRQOL, and socioeconomic outcomes within the Childhood Cancer Survivor Study (CCSS).MethodsThe CCSS is a retrospective cohort study with longitudinal follow-up concerning survivors of pediatric cancer who were diagnosed between 1970 and 1986. Mortality rates per 100 person-years were calculated across 3 periods: 1) prior to stroke; 2) after first stroke and before recurrent stroke; and 3) after recurrent stroke. Socioeconomic outcomes, the standardized Brief Symptoms Inventory-18, the Medical Outcomes Study 36-Item Short Form Health Survey, and the CCSS-Neurocognitive Questionnaire also were assessed.ResultsAmong 14,358 participants (median age, 39.7&nbsp;years), 224 had a stroke after their cancer diagnosis (single stroke in 161 patients and recurrent stroke in 63 patients). Based on 2636 deaths, all-cause late mortality rates were 0.70 (95% CI, 0.68-0.73) prior to stroke, 1.03 (95% CI, 0.73-1.46) after the first stroke, and 2.42 (95% CI, 1.48-3.94) after the recurrent stroke. Among 7304 survivors, those with stroke were more likely to live with a caregiver (single stroke odds ratio [OR], 2.3 [95% CI, 1.4-3.8]; and recurrent stroke OR, 5.3 [95% CI, 1.7-16.8]) compared with stroke-free survivors. Stroke negatively impacted task efficiency (single stroke OR, 2.4 [95% CI, 1.4-4.1] and recurrent stroke OR, 3.3 [95% CI, 1.1-10.3]) and memory (single stroke OR, 2.1 [95% CI, 1.2-3.7]; and recurrent stroke OR, 3.5 [95% CI, 1.1-10.5]).ConclusionsStroke and stroke recurrence are associated with increased mortality and negatively impact HRQOL measures in survivors of pediatric cancer

    Psychometric evaluation of the Chinese version of the Utrecht Grief Rumination Scale

    Get PDF
    Given the severe mental health consequences that may ensue after bereavement, it is crucial to better understand malleable cognitive factors that are associated with poorer bereavement outcomes. Grief rumination (i.e. repetitive thinking about the causes and consequences of a loss) is a malleable cognitive process that is concurrently and longitudinally associated with post-loss mental health problems. To assess grief rumination, the English and Dutch Utrecht Grief Rumination Scales (UGRS) were recently developed. The current study examined the reliability and validity of a Chinese version of the UGRS. Three hundred and ninety-three Chinese adults (56% women) bereaved on average 16.88 months ago filled out online questionnaires assessing demographic and loss-related characteristics, grief rumination (UGRS), trait rumination, trait mindfulness, and anxious, depressive, and prolonged grief symptoms. Confirmatory factor analyses showed that a second-order five-factor hierarchical model provided the best factor structure for the Chinese UGRS. UGRS scale and subscale scores demonstrated acceptable internal consistency. Grief rumination had a moderate association with trait rumination and a low negative association with trait mindfulness, providing convergent and discriminant validity evidence. Test-criterion validity evidence was also provided. UGRS scores could distinguish bereaved groups with different relationships with the deceased. Moreover, the grief rumination was associated with symptoms of anxiety, depression, and prolonged grief even after controlling for demographic and loss-related variables, trait rumination, and trait mindfulness. The Chinese UGRS appears a valid and reliable instrument to assess grief rumination in Chinese bereaved individuals

    Knowledge, Attitudes, and Interactions with Chaplains and Nursing Northwell Health Outcomes: A Survey Study

    Get PDF
    © 2020, Springer Science+Business Media, LLC, part of Springer Nature. We conducted a cross-sectional survey of nursing Northwell Health (n = 51) in an academic hospital finding a significant inverse relationship between the frequency of chaplaincy interaction and perceived stress (r = − 0.27, p = 0.05). We also found a significant positive relationship between rated importance of having a chaplain at the hospital and secondary trauma (r = 0.30, p = 0.03). There was a significant positive relationship between religiosity and rated importance for having a chaplain (r = 0.30, p = 0.03) and rated helpfulness of chaplains (r = 0.32, p = 0.02). Similarly, there was a significant positive relationship between spirituality and average length of conversations with a chaplain, rated importance for having a chaplain, and helpfulness of chaplains (r = 0.32, p = 0.03; r = 0.44, p = 0.001; and r = 0.52, p = 0.0001, respectively). Interaction with chaplains is associated with decreased employee perceived stress for nursing Northwell Health who provide care for severely ill patients

    General Relativistic Contributions in Transformation Optics

    Full text link
    One potentially realistic specification for devices designed with transformation optics is that they operate with high precision in curved space-time, such as Earth orbit. This raises the question of what, if any, role does space-time curvature play in determining transformation media? Transformation optics has been based on a three-vector representation of Maxwell's equations in flat Minkowski space-time. I discuss a completely covariant, manifestly four-dimensional approach that enables transformations in arbitrary space-times, and demonstrate this approach for stable circular orbits in the spherically symmetric Schwarzschild geometry. Finally, I estimate the magnitude of curvature induced contributions to satellite-borne transformation media in Earth orbit and comment on the level of precision required for metamaterial fabrication before such contributions become important.Comment: 14 pages, 3 figures. Latest version has expanded analysis, corresponds to published versio
    corecore