26 research outputs found

    Conceptual Design and Sensitivity Analysis of MRI Magnets from REBCO HTS Tapes

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    An actively shielded wide-bore magnet system has been designed for magnetic resonance imaging. The gradient-based optimization solver of COMSOL Multiphysics has been used to obtain an optimum geometrical arrangement of symmetrical electromagnets in the magnetic resonance imaging (MRI) system. To generate a high and homogeneous magnetic field, we employed a second-generation rare-earth barium-copper-oxide (REBCO) high-temperature superconductor (HTS), which was wound into 10 double pancake coils (DPC). The dimensions of the DPC sets have been chosen considering the size of REBCO HTS tapes, and the optimized design solution provides magnetic field, stray field, and current passing through the HTS tapes on each DPC set. The design details of a 1.5 T actively shielded magnet as well as the sensitivity analysis of the inhomogeneity, stray field, and currents with respect to coil positions have been presented. Optimum parameters for various designs are listed. The inhomogeneity of 1.23 ppm in the 200 mm diameter of spherical volume (DSV) and a stray field of as low as 0.05 G outside of the 5 m distance were achieved. Additionally, a low peak field of 2.40 T in DPC sets has been accomplished. © 2002-2011 IEEE

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Mehmet Orhan Kürümoğlu’nun hayatı, bakanlık ve senatörlük dönemi ve AP'den ayrılışı

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    Ankara : İhsan Doğramacı Bilkent Üniversitesi İktisadi, İdari ve Sosyal Bilimler Fakültesi, Tarih Bölümü, 2016.This work is a student project of the The Department of History, Faculty of Economics, Administrative and Social Sciences, İhsan Doğramacı Bilkent University.by Öztürk, İbrahim Mert

    A study of olive mill wastewaters obtained from different treatment processes effects on chemical and microbial properties of a Typic Xerofluvent soil and wheat yield

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    This study was carried out to investigate the potential for the usability of treated olive mill wastewater (OMW) as an organic amendment in agricultural soils under Mediterranean climate conditions. OMW was treated by two different treatment processes as economical (E-OMW) and advanced (A-OMW). the treated OMWs and raw OMW (R-OMW) were applied to a loamy soil at a rate of 100 m3 ha–1 year–1 for 2 years. Soils were sampled 15 days and about 5 months (at harvest) after OMW application for chemical and microbial analyses in each year. the total concentrations of N, P, Cu, Zn, and phenol of R-OMW decreased after both treatment processes while salinity (EC) and the total amounts of K, Na, and Ca increased. the applications of OMW caused changes in soil chemical (pH, EC, Pext, Kext) and microbial (microbial biomass-C (MB-C), microbial biomass-N (MB-N), basal soil respiration (BSR), N-mineralization (N-min)) characteristics (P < 0.05). in the second year of the experiment, initial samplings showed that the values of soil pH and EC increased significantly under all OMW applications compared to the control. High Pext concentrations were determined in soils amended with R-OMW, while there were high Kext concentrations in soils amended with the treated OMWs. the increases determined in MB-C and MB-N at all sampling times resulted in high MB-C/TOC and MB-N/TN ratios in soils amended with the treated OMWs. the wheat grain yield over the 2-year period showed that the application of the treated OMWs had a positive effect. It was determined that no negative effects occurred for either soil properties or wheat growth with the treated OMW applied at rates of up to 100 m3 ha–1. the addition of treated OMW after removal of its phenolic components may be considered as a good option for evaluating this waste in countries where OMW causes serious environmental pollution
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