63 research outputs found

    Generation and transport of a low energy intense ion beam

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    The paper describes experiments on the generation and transport of a low energy (70-120 keV), high intensity (10-30 A/cm(2)) microsecond duration H+ ion beam (IB) in vacuum and plasma. The IB was generated in a magnetically insulated diode (MID) with an applied radial B field and an active hydrogen-puff ion source. The annular IB, with an initial density of j(i)similar to10-20 A/cm(2) at the anode surface, was ballistically focused to a current density in the focal plane of 50-80 A/cm(2). The postcathode collimation and transport of the converging IB were provided by the combination of a "concave" toroidal magnetic lens followed by a straight transport solenoid section. With optimized MID parameters and magnetic fields in the lens/solenoid system, the overall efficiency of IB transport at the exit of the solenoid 1 m from the anode was similar to 50% with an IB current density of 20 A/cm(2). Two-dimensional computer simulations of post-MID IB transport supported the optimization of system parameters. (C) 2004 American Institute of Physics

    Determinants of women's satisfaction with maternal health care: a review of literature from developing countries.

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    BACKGROUND: Developing countries account for 99 percent of maternal deaths annually. While increasing service availability and maintaining acceptable quality standards, it is important to assess maternal satisfaction with care in order to make it more responsive and culturally acceptable, ultimately leading to enhanced utilization and improved outcomes. At a time when global efforts to reduce maternal mortality have been stepped up, maternal satisfaction and its determinants also need to be addressed by developing country governments. This review seeks to identify determinants of women's satisfaction with maternity care in developing countries. METHODS: The review followed the methodology of systematic reviews. Public health and social science databases were searched. English articles covering antenatal, intrapartum or postpartum care, for either home or institutional deliveries, reporting maternal satisfaction from developing countries (World Bank list) were included, with no year limit. Out of 154 shortlisted abstracts, 54 were included and 100 excluded. Studies were extracted onto structured formats and analyzed using the narrative synthesis approach. RESULTS: Determinants of maternal satisfaction covered all dimensions of care across structure, process and outcome. Structural elements included good physical environment, cleanliness, and availability of adequate human resources, medicines and supplies. Process determinants included interpersonal behavior, privacy, promptness, cognitive care, perceived provider competency and emotional support. Outcome related determinants were health status of the mother and newborn. Access, cost, socio-economic status and reproductive history also influenced perceived maternal satisfaction. Process of care dominated the determinants of maternal satisfaction in developing countries. Interpersonal behavior was the most widely reported determinant, with the largest body of evidence generated around provider behavior in terms of courtesy and non-abuse. Other aspects of interpersonal behavior included therapeutic communication, staff confidence and competence and encouragement to laboring women. CONCLUSIONS: Quality improvement efforts in developing countries could focus on strengthening the process of care. Special attention is needed to improve interpersonal behavior, as evidence from the review points to the importance women attach to being treated respectfully, irrespective of socio-cultural or economic context. Further research on maternal satisfaction is required on home deliveries and relative strength of various determinants in influencing maternal satisfaction

    Monte Carlo Transport Simulation Techniques for Stellarator Fusion Experiments

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    We describe an implementation of a particle orbit-following simulation approach to the Monte Carlo calculation of neoclassical transport coecients which has been developed for application to the H-1NF Heliac. We compare and contrast some Monte Carlo transport coecient estimators that can be used in such computer codes, from both physical and computational perspectives, and we make recommendations for their use. Transport coecient calculations are performed for the H-1NF in conditions that will be available after the full National Facility upgrade.</jats:p
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