PMU-Based Dynamic Model Calibration of Type 4 Wind Turbine Generators

In today’s power system where the share of renewables is rapidly increasing, the system now exhibits a more dynamic behavior compared to the past. Therefore, the importance of dynamic simulations at every level of the power system is crucial for the system operators. However, calibration of model parameters and their regular controlling are required to simulate the real-life behavior of the system correctly. This paper aims to improve the dynamic simulations by calibrating the parameters of the Type 4 wind turbine generator model. The employed method uses an ensemble Kalman filter to estimate the model states and calibrate parameters. For the simulation environment, SIEMENS PSS®E software (v35.5) and its PythonTM API are utilized. After the sensitivity and collinearity analyses, during the transient event, the erroneous model parameters are calibrated

The effects of prenatal exposure to a 900-MHz electromagnetic field on the 21-day-old male rat heart

Mercantepe, Tolga/0000-0002-8506-1755;WOS: 000364542800018PubMed: 25166431The growing spread of mobile phone use is raising concerns about the effect on human health of the electromagnetic field (EMF) these devices emit. the purpose of this study was to investigate the effects on rat pup heart tissue of prenatal exposure to a 900 megahertz (MHz) EMF. For this purpose, pregnant rats were divided into experimental and control groups. Experimental group rats were exposed to a 900MHz EMF (1h/d) on days 13-21 of pregnancy. Measurements were performed with rats inside the exposure box in order to determine the distribution of EMF intensity. Our measurements showed that pregnant experimental group rats were exposed to a mean electrical field intensity of 13.77V/m inside the box (0.50W/m(2)). This study continued with male rat pups obtained from both groups. Pups were sacrificed on postnatal day 21, and the heart tissues were extracted. Malondialdehyde, superoxide dismutase and catalase values were significantly higher in the experimental group rats, while glutathione values were lower. Light microscopy revealed irregularities in heart muscle fibers and apoptotic changes in the experimental group. Electron microscopy revealed crista loss and swelling in the mitochondria, degeneration in myofibrils and structural impairments in Z bands. Our study results suggest that exposure to EMF in the prenatal period causes oxidative stress and histopathological changes in male rat pup heart tissue

Case report: acute pancreatitis caused by postcholecystectomic hemobilia

Background: Hemobilia is a rare cause of upper GI bleeding and the reasons for the majority of the cases are iatrogenic. It is also one of the rarest vascular complication following laparoscopic cholecystectomy but acute pancreatitis due to postcholecystectomic hemobilia as a late complication of cholecystectomy is not yet described

Can prenatal exposure to a 900 MHz electromagnetic field affect the morphology of the spleen and thymus, and alter biomarkers of oxidative damage in 21-day-old male rats?

Mercantepe, Tolga/0000-0002-8506-1755;WOS: 000365607200007PubMed: 25985826We investigated the effects of a 900 Megahertz (MHz) electromagnetic field (EMF), applied during the prenatal period, on the spleen and thymus of 21-day-old male rat pups. Pregnant Sprague-Dawley rats were divided into control and EMF groups. We applied 900 MHz EMF for 1 h/day to the EMF group of pregnant rats. Newborn male rat pups were removed from their mothers and sacrificed on postnatal day 21. Spleen and thymus tissues were excised and examined. Compared to the control group, thymus tissue malondialdehyde levels were significantly higher in the group exposed to EMF, while glutathione levels were significantly decreased. Increased malondialdehyde and glutathione levels were observed in splenic tissue of rats exposed to EMF, while a significant decrease occurred in superoxide dismutase values compared to controls. Transmission electron microscopy showed pathological changes in cell morphology in the thymic and splenic tissues of newborn rats exposed to EMF. Exposure to 900 MHz EMF during the prenatal period can cause pathological and biochemical changes that may compromise the development of the male rat thymus and spleen