69 research outputs found

    A CFD-based design methodology for hydraulic turbines applied to a case study in Turkey

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    Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Hydraulic turbines are turbo machines which produce electricity from hydraulic energy. Francis type turbines are the most common one in use today. The design of these turbines requires high engineering effort since each turbine is tailor made due to different head and discharge values. Therefore each component of the turbine is designed specifically. During the last decades, Computational Fluid Dynamics (CFD) has become very useful tool to predict hydraulic machinery performance and save time and money for designers. This paper describes a design methodology to optimize a Francis turbine by integrating theoretical and experimental fundamentals of hydraulic machines and commercial CFD codes.dc201

    Conceptual design of a hydroelectric power plant for a rehabilitation project

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    This study presents the conceptual design of a hydroelectric power plant, as a part of a large scale rehabilitation project for an existing power plant in Antalya, Turkey. The aim of the rehabilitation project is to increase the power and efficiency of the plant and its scope includes CFD aided turbine design, model production and tests, the design, production and implementation of the turbine, generator and the SCADA system. This study is the first attempt, as a preliminary study, to handle the problem and perform a conceptual design of the hydroelectric power plant. The existing plant is modeled to estimate the head and flow rate characteristics at various sections of the system. The net head and flow rate of the turbine are estimated. Transient analyses of the system are also performed to evaluate water hammer characteristics. The results of the transient analyses provide the inputs for the design of by-pass pipeline and pressure relief valve. The estimated net head and flow rate from the simulations are used as inputs for the preliminary design. The dimensions of the spiral case, the diameter of the stay vanes and guide vanes, wicket gate heights, runner diameter and rotational speed, runaway characteristics and preliminary output power are determined. The best efficiency point and the design point of the turbine are also obtained as the net head versus the flow rate. These results provide an idea on the feasibility of the increase in power.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

    Electrospun fluorescent nanofibers for explosive detection

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    Development of an instant on-site visual detection method for 2,4,6 trinitrotoluene (TNT) has become a significant requirement of the hour towards a secured society and a greener environment. Despite momentous advances in the respective field, a portable and reliable method for quick and selective detection of TNT still poses a challenge to many reasons attributing to inappropriate usage in subordinate areas and untrained personnel. The recent effort on the fluorescent based detection represents as one of easy method in terms of fast response time and simple on/off detection. Therefore, this chapter provides a consolidation of information relating to recent advances in fluorescence based TNT detection.Further, the main focus will be towards advances in the nanofibers based TNT detection and their reason to improving thesensitivity. © Springer International Publishing Switzerland 2015

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    20-Year Risks of Breast-Cancer Recurrence after Stopping Endocrine Therapy at 5 Years

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    The administration of endocrine therapy for 5 years substantially reduces recurrence rates during and after treatment in women with early-stage, estrogen-receptor (ER)-positive breast cancer. Extending such therapy beyond 5 years offers further protection but has additional side effects. Obtaining data on the absolute risk of subsequent distant recurrence if therapy stops at 5 years could help determine whether to extend treatment
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