119 research outputs found

    Stator flux optimization on direct torque control with fuzzy logic

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    The Direct Torque Control (DTC) is well known as an effective control technique for high performance drives in a wide variety of industrial applications and conventional DTC technique uses two constant reference value: torque and stator flux. In this paper, fuzzy logic based stator flux optimization technique for DTC drives that has been proposed. The proposed fuzzy logic based stator flux optimizer self-regulates the stator flux reference using induction motor load situation without need of any motor parameters. Simulation studies have been carried out with Matlab/Simulink to compare the proposed system behaviors at vary load conditions. Simulation results show that the performance of the proposed DTC technique has been improved and especially at low-load conditions torque ripple are greatly reduced with respect to the conventional DTC.Comment: 8 pages, 8 figures, Itca 2012 conferenc

    Climate change impact assessment on mild and extreme drought events using copulas over Ankara, Turkey

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    From Springer Nature via Jisc Publications RouterHistory: received 2019-10-26, accepted 2020-05-04, registration 2020-05-04, pub-electronic 2020-05-22, online 2020-05-22, pub-print 2020-08Publication status: PublishedFunder: University of ManchesterAbstract: Climate change, one of the major environmental challenges facing mankind, has caused intermittent droughts in many regions resulting in reduced water resources. This study investigated the impact of climate change on the characteristics (occurrence, duration, and severity) of meteorological drought across Ankara, Turkey. To this end, the observed monthly rainfall series from five meteorology stations scattered across Ankara Province as well as dynamically downscaled outputs of three global climate models that run under RCP 4.5 and RCP 8.5 scenarios was used to attain the well-known SPI series during the reference period of 1986–2018 and the future period of 2018–2050, respectively. Analyzing drought features in two time periods generally indicated the higher probability of occurrence of drought in the future period. The results showed that the duration of mild droughts may increase, and extreme droughts will occur with longer durations and larger severities. Moreover, joint return period analysis through different copula functions revealed that the return period of mild droughts will remain the same in the near future, while it declines by 12% over extreme droughts in the near future

    Inactivating KISS1 mutation and hypogonadotropic hypogonadism

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    Gonadotropin-releasing hormone (GnRH) is the central regulator of gonadotropins, which stimulate gonadal function. Hypothalamic neurons that produce kisspeptin and neurokinin B stimulate GnRH release. Inactivating mutations in the genes encoding the human kisspeptin receptor (KISS1R, formerly called GPR54), neurokinin B (TAC3), and the neurokinin B receptor (TACR3) result in pubertal failure. However, human kisspeptin loss-of-function mutations have not been described, and contradictory findings have been reported in Kiss1-knockout mice. We describe an inactivating mutation in KISS1 in a large consanguineous family that results in failure of pubertal progression, indicating that functional kisspeptin is important for puberty and reproduction in humans. (Funded by the Scientific and Technological Research Council of Turkey [TÜBİTAK] and others.)http://www.nejm.org/nf201

    Minimally invasive treatment of patients with bronchobiliary fistula: a case series

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    <p>Abstract</p> <p>Introduction</p> <p>Bronchobiliary fistula is an uncommon complication secondary to hepatobiliary surgery. Bilioptysis is a pathognomic finding for bronchobiliary fistulas. Diagnosis may be easily established in the light of clinical history, which can be aided by imaging studies to pinpoint the exact location. Some diagnostic procedures such as endoscopic retrograde cholangiopancreatectomy are also useful for treatment.</p> <p>Case presentation</p> <p>We present three Turkish patients with bronchobiliary fistula secondary to previous hepatic surgery due to hydatid cyst in two, a 19-year-old and a 47-year-old man, and iatrogenic trauma of the common bile duct by endoscopy in a 35-year-old man. All of the patients were successfully treated by minimally invasive methods including percutaneous drainage and endoscopic retrograde cholangiopancreatography.</p> <p>Conclusion</p> <p>We suggest that bronchobiliary fistula could be managed through conservative treatment methods which do not require in-hospital follow-up, particularly in uncomplicated cases. Otherwise, surgical management can be unavoidable.</p

    EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

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    More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369
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