Centralized Microgrid Control System in Compliance with IEEE 2030.7 Standard Based on an Advanced Field Unit

The necessity for the utilization of microgrids emerges from the integration of distributed energy resources, electric vehicles, and battery storage systems into the conventional grid structure. In order to achieve a proper operation of the microgrid, the presence of a microgrid control system is crucial. The IEEE 2030.7 standard defines the microgrid control system as a key element of the microgrid that regulates every aspect of it at the point-of-interconnection with the distribution system, and autonomously manages operations such as the transitions of operating modes. In this paper, a microgrid control system is developed to achieve real-time monitoring and control through a centralized approach. The controller consists of a centralized server and advanced field units that are also developed during this work. The control functions of the centralized server ensure the proper operation during grid-connected and island modes, using the real-time data received via the advanced field unit. The developed server and the field unit constitute a complete system solution. The server is composed of control function and communication, database, and user interface modules. The microgrid control functions comprise dispatch and transition core-level functions. A rule-based core-level dispatch function guarantees the security of supply to critical loads during the islanded mode. The core-level transition function accomplishes a successful transition between the operation modes. Moreover, a communication framework and a graphical user interface are implemented. The presented system is tested through thecases based on the IEEE 2030.8 standard

Double-balloon endoscopy in patients with Peutz-Jeghers syndrome

Background/aims: Peutz-Jeghers syndrome is a rare hereditary syndrome characterized by mucocutaneous pigmentation and hamartomatous polyps of the gastrointestinal tract, especially-in the small intestine. Double-balloon endoscopy is a new endoscopic technique that enables both endoscopic visualization of the entire small bowel and therapeutic interventions in a single procedure. In this study, we evaluate the efficacy and safety of double-balloon endoscopy for both treatment and surveillance of patients with Peutz-Jeghers syndrome. Materials and Methods: We retrospectively evaluated 7 consecutive patients who were referred to Dokuz Eylul University, Gastroenterology Department, with the diagnosis of Peutz-Jeghers syndrome between 2007 and 2010. Results: Patients with Peutz-Jeghers syndrome (M/F: 5/2) underwent a total 31 double-balloon endoscopy procedures: 21 by the oral route, 9 by the anal route, and 1 intraoperatively. All of the patients had a history of laparotomy and small bowel resection due to complications such as invagination and ileus. In 7 patients, we found a total of 110 polyps >= 10 mm in diameter (10-100 mm) and polypectomies were performed in all of them. The only complication was a bleeding after polypectomy, which was controlled by sclerotherapy. In 1 patient, because of the intraabdominal adhesions due to past laparotomies, polypectomy was done by intraoperative endoscopy. In 2 of our patients, we made surveillance colonoscopies, found new polyps in the small intestine, and performed polypectomies. Conclusions: Double-balloon endoscopy is an effective and safe endoscopic technique, and represents a milestone for both treatment and surveillance of patients with Peutz-Jeghers syndrome. Polypectomies made in the small intestine might decrease the complication rate due to these polyps and the need for surgery

The effect of macromolecule and growth factor combinations on in vitro development of bovine embryos

WOS: 000356079900009This study was conducted to determine the effects of different macromolecule sources added to synthetic oviduct fluid (SOF) culture medium supplemented with growth factors on the development of bovine embryos and blastocyst morphology. Zygotes were distributed into 5 treatment groups. Cleavage, morula, and blastocyst rates were evaluated under a stereomicroscope. Trophectoderm (TE) and inner cell mass (ICM) cells were determined by differential staining method. It was found that bovine serum albumin (BSA), either alone or in combination with growth factors, as compared to the control or polyvinyl-alcohol (PVA) resulted in higher embryo yield and faster development during early bovine embryo culture. The quality of bovine embryos, based on the number of blastocyst cells and the ratio of ICM to total blastomeres, was affected by the sources of macromolecules and their combinations with growth factors. Growth factors supplemented to SOFaa media with BSA and PVA significantly increased the number of ICM cells and the ratio of ICM cells to total number of cells. In conclusion, replacing BSA with PVA depressed the blastocyst rate and cell numbers, and the number of blastomeres and ICM and TE cell numbers were affected by both the type of macromolecule and the growth factor supplements.Research Foundation of Ondokuz Mayis UniversityOndokuz Mayis University [PYO.VET.1901.09.002]We wish to thank Dr Arslan for statistical analysis. This work was supported by the Research Foundation of Ondokuz Mayis University (PYO.VET.1901.09.002)

DC Link Capacitor Optimization for Integrated Modular Motor Drives

In this paper, selection of optimum DC link capacitor for Integrated Modular Motor Drives (IMMD) is presented. First, a review of IMMD technologies is given and current research and future prospects are studied. Inverter topologies and gate drive techniques are evaluated in terms of DC link performance. The urge for volume reduction in IMMD poses a challenge for the selection of optimum DC link capacitor. DC Link capacitor types are discussed and critical aspects in selecting the DC links capacitor are listed. Analytical modeling of DC link capacitor parameters is performed and it is verified by simulations conducted using MATLAB/Simulink. Optimum selection of DC link capacitor is achieved based on the electrical, thermal and economical model

Acute Buried Bumper Syndrome with Gastric Perforation and Peritonitis: A Rare Complication of Percutaneous Endoscopic Gastrostomy: Case Report

Percutaneous endoscopic gastrostomy (PEG) is a broadly accepted procedure of enteral feeding for patients with inadequate oral intake. The side effects and complications of PEG are becoming more evident with its increasing use. Here, we report a case of buried bumper syndrome, gastric perforation and peritonitis after PEG. In our case, perforated area was closed endoscopically by using hemoclips. The patient was treated with intravenous broad spectrum antibiotics for 10 days and fed by parenteral nutrition. The patient responded well to medical treatment therefore there was not any need for a surgical exploration. Follow up endoscopy was performed 15 days later which showed closure of the perforation area. A new PEG tube was inserted 1 month later

Investigation of Turn-on and Turn-off Characteristics

In this paper, turn-on and turn-off switching behavior of 650V enhancement-mode GaN power FETs are investigated. An analytical model is developed to analyze the current-voltage characteristics of the device during switching transients both with and without the effects of parasitic components. In addition, the effect of the temperature and circuit parameters on the switching characteristics are investigated

Comparison of Inverter Topologies Suited for Integrated Modular Motor Drive Applications

In this paper, various inverter topologies are compared for integrated modular motor drive (IMMD) applications. Two-level voltage source inverter (2L-VSI), three level voltage source inverter (3L-VSI) and series/parallel combinations of these topologies with system level modularity are compared in terms of voltage and current harmonic spectrum, passive component sizes and motor drive efficiency. New generation wide band-gap GaN power semiconductor devices are utilized in modular topologies and they are compared with a conventional IGBT motor drive. The effect of phase-shifting between the PWM carrier signals of parallel connected modules and its contribution to size reduction is investigated. IMMD structure has proven to have a superior efficiency compared to conventional motor drives, thanks to the utilization of GaNs. It has been shown that over 98% motor drive efficiency can be achieved for 8kW IMMD by using a newly proposed topology where 2L-VSI converters are connected both in series and parallel on the DC link

Ectopic pancreas presenting with intractable diarrhea: Case report

Ectopic pancreas is an uncommon congenital anomaly, which is usually found incidentally in clinical practice. It presents with nonspecific gastrointestinal symptoms like epigastric pain and dyspepsia and rarely with the clinical findings of obstructive jaundice or intestinal obstruction, or it may mimic gastrointestinal system cancer. Herein, we describe a case of ectopic pancreas in the duodenum, which was the cause of the intractable diarrhea. In our patient, upper gastrointestinal endoscopy and endoscopic ultrasonography revealed a 1.5 cm submucosal lesion, which was umbilicated centrally with a normal in appearance overlying mucosa. Endoscopic biopsy of the lesion was normal. Pathological examination of the lesion after surgical excision was compatible with ectopic pancreas. After total excision of the lesion, the clinical findings of the patient normalized. Ectopic pancreas presenting with diarrhea has not been reported previously in the literature