8,471 research outputs found

    Development of low modulus material for use in ceramic gas path seal applications

    Get PDF
    Three candidate materials were examined: Brunsbond (R) Pad; plasma sprayed porous NiCrAlY; and plasma sprayed low modulus microcracked zirconia. Evaluation consisted of mechanical, thermophysical, and oxidation resistance testing along with optical microscopy and a feasibility demonstration of attaching the material to a suitable substrate. The goals of the program were the following: feasibility of fastening or depositing the low modulus system onto a broad range of substrate alloys; feasibility of depositing or forming the low modulus system to a thickness of 0.19 cm to 0.38 cm; potential to attain a modulus of elasticity in the range of 3.4 to 6.9 GPa (0.5 to 1.0 MSI), and an ultimate strength of 17.2 MPa (2.5 ksi); suitable thermal conductivity; and static oxidation life of at least 1000 hours at 1311 K. The results of the program indicate that all three systems offer attractive properties as a strain isolator material

    Determinants of anemia and hemoglobin concentration in haitian school-aged children

    Get PDF
    Anemia diminishes oxygen transport in the body, resulting in potentially irreversible growth and developmental consequences for children. Limited evidence for determinants of anemia exists for school-aged children. We conducted a cluster randomized controlled trial in Haiti from 2012 to 2013 to test the efficacy of a fortified school snack. Children (N = 1,047) aged 3–13 years were followed longitudinally at three time points for hemoglobin (Hb) concentrations, anthropometry, and bioelectrical impedance measures. Dietary intakes, infectious disease morbidities, and socioeconomic and demographic factors were collected at baseline and endline. Longitudinal regression modeling with generalized least squares and logit models with random effects identified anemia risk factors beyond the intervention effect. At baseline, 70.6% of children were anemic and 2.6% were severely anemic. Stunting increased the odds of developing anemia (adjusted odds ratio [OR]: 1.48, 95% confidence interval [CI]: 1.05–2.08) and severe anemia (adjusted OR: 2.47, 95% CI: 1.30–4.71). Parent-reported vitamin A supplementation and deworming were positively associated with Hb concentrations, whereas fever and poultry ownership showed a negative relationship with Hb concentration and increased odds of severe anemia, respectively. Further research should explore the full spectrum of anemia etiologies in school children, including genetic causes

    A qualitative analysis of staff-client interactions within a breast cancer assessment clinic

    Get PDF
    Objectives Breast screening clients recalled to an assessment clinic experience high levels of anxiety. The culture of the assessment clinic may impact upon client experience, which may influence their future re-engagement in screening. This study aimed to explore the culture of staff-client interactions within a breast cancer assessment clinic. Materials and methods Following an ethnographic approach, twenty-three client journeys were observed, followed by semi-structured interviews with the clients. The observation and interview data were analysed to produce research themes, which were then explored within two focus groups to add a practitioner perspective. Results Multiple staff-client interaction events were observed over a period of several weeks. Client interview feedback was overwhelmingly positive. Three recurrent and sequential themes emerged: breaking down barriers, preparing the ground and sign-posting. These themes outline the changing focus of staff-client interactions during the client's clinic journey, encompassing how anxieties were expressed by clients, and responded to by practitioners. Conclusion This study was the first to explore in depth the staff-client interaction culture within a breast assessment clinic using an ethnographic approach. A new perspective on professional values and behaviours has been demonstrated via a model of staff-client interaction. The model documents the process of guiding the client from initial confusion and distress to an enhanced clarity of understanding. A recommendation most likely to have a positive impact on the client experience is the introduction of a client navigator role to guide the clients through what is often a lengthy, stressful and confusing process

    Mainstreaming Mental Health Care in 42 Countries.

    Get PDF
    Abstract-Global consensus and national policies have emphasized deinstitutionalization, or a shift in providing mental health care from institutional to community settings. Yet, psychiatric hospitals and asylums receive the majority of mental health funding in many countries, at odds with research evidence that suggests that services should be delivered in the community. Our aim is to investigate the norms, actors, and strategies that influence the uptake of deinstitutionalization internationally. Our study is informed by prior literature on management and implementation science. The success and failure of mental health care operations depend on identifying and overcoming challenges related to implementing innovations within national contexts. We surveyed 78 experts spanning 42 countries on their knowledge and experiences in expanding community-based mental health care and/or downsizing institution-based care. We also asked them about the contexts in which said methods were implemented in a country. We found that mental health care, whether it is provided in institutions or in the community, does not seem to be standardized across countries. Our analysis also showed that moving deinstitutionalization forward requires meaningful engagement of three types of actors: government officials, health care professionals, and local experts. Progress toward deinstitutionalization depends on the partnerships formed among these actors and with diverse stakeholders, which have the potential to garner resources and to scale-up pilot projects. In conclusion, different countries have adapted deinstitutionalization in ways to meet idiosyncratic situations and population needs. More attention should be given to the management and implementation strategies that are used to augment treatment and preventive services

    The 1979 Southeastern Virginia Urban Plume Study (SEV-UPS): Surface and airborne studies

    Get PDF
    The operation of two surface monitoring stations (one in downtown Norfolk, Virginia, one south of the city near the Great Dismal Swamp) and the collection of 40 hours of airborne measurements is described. Surface site measurements of ozone, oxides of nitrogen, sulfur dioxide, temperature, dew point, b sub seat, and condensation nuclei were made. Instrument calibrations, quality assurance audits, and preliminary data analysis in support of the Urban Plume Study were also made. The air pollution problems that were addressed are discussed. Data handling procedures followed for the surface stations are presented. The operation of the aircraft sampling platform is described. Aircraft sampling procedures are discussed. A preliminary descriptive analysis of the aircraft data is given along with data or plots for surface sites, airborne studies, hydrocarbon species, and instrument performance audits. Several of the aircraft flights clearly show the presence of an urban ozone plume downwind of Norfolk in the direction of the mean wind flow

    In situ sensors for measurements in the global trosposphere

    Get PDF
    Current techniques available for the in situ measurement of ambient trace gas species, particulate composition, and particulate size distribution are reviewed. The operational specifications of the various techniques are described. Most of the techniques described are those that have been used in airborne applications or show promise of being adaptable to airborne applications. Some of the instruments described are specialty items that are not commercially-available. In situ measurement techniques for several meteorological parameters important in the study of the distribution and transport of ambient air pollutants are discussed. Some remote measurement techniques for meteorological parameters are also discussed. State-of-the-art measurement capabilities are compared with a list of capabilities and specifications desired by NASA for ambient measurements in the global troposphere

    Spatial adaptivity of the SAAF and Weighted Least Squares (WLS) forms of the neutron transport equation using constraint based, locally refined, isogeometric analysis (IGA) with dual weighted residual (DWR) error measures

    Get PDF
    This paper describes a methodology that enables NURBS (Non-Uniform Rational B-spline) based Isogeometric Analysis (IGA) to be locally refined. The methodology is applied to continuous Bubnov-Galerkin IGA spatial discretisations of second-order forms of the neutron transport equation. In particular this paper focuses on the self-adjoint angular flux (SAAF) and weighted least squares (WLS) equations. Local refinement is achieved by constraining degrees of freedom on interfaces between NURBS patches that have different levels of spatial refinement. In order to effectively utilise constraint based local refinement, adaptive mesh refinement (AMR) algorithms driven by a heuristic error measure or forward error indicator (FEI) and a dual weighted residual (DWR) or goal-based error measure (WEI) are derived. These utilise projection operators between different NURBS meshes to reduce the amount of computational effort required to calculate the error indicators. In order to apply the WEI to the SAAF and WLS second-order forms of the neutron transport equation the adjoint of these equations are required. The physical adjoint formulations are derived and the process of selecting source terms for the adjoint neutron transport equation in order to calculate the error in a given quantity of interest (QoI) is discussed. Several numerical verification benchmark test cases are utilised to investigate how the constraint based local refinement affects the numerical accuracy and the rate of convergence of the NURBS based IGA spatial discretisation. The nuclear reactor physics verification benchmark test cases show that both AMR algorithms are superior to uniform refinement with respect to accuracy per degree of freedom. Furthermore, it is demonstrated that for global QoI the FEI driven AMR and WEI driven AMR produce similar results. However, if local QoI are desired then WEI driven AMR algorithm is more computationally efficient and accurate per degree of freedom

    Zero-Gravity Atmospheric Cloud Physics Experiment Laboratory engineering concepts/design tradeoffs. Volume 1: Study results

    Get PDF
    The work is summarized which was accomplished from January 1974 to October 1974 for the Zero-Gravity Atmospheric Cloud Physics Laboratory. The definition and development of an atmospheric cloud physics laboratory and the selection and delineation of candidate experiments that require the unique environment of zero gravity or near zero gravity are reported. The experiment program and the laboratory concept for a Spacelab payload to perform cloud microphysics research are defined. This multimission laboratory is planned to be available to the entire scientific community to utilize in furthering the basic understanding of cloud microphysical processes and phenomenon, thereby contributing to improved weather prediction and ultimately to provide beneficial weather control and modification
    • …
    corecore