Vagal Nerve Schwannoma Clinically Mimicking Gastrointestinal Stromal Tumor: Report of a Case

Introduction: Mesenchymal tumors of the gastrointestinal (GI) tract are mainly comprised of a spectrum of spindle cell tumors which include gastrointestinal stromal tumors (GISTs), leiomyomas or leiomyosarcomas, and schwannomas. As all of these tumors of the GI are located in the submucosal layer of the bowell wall, differential diagnosis is very difficult. Histopathological evaluation using immunohistochemical staining is required for the definitive diagnosis.Presentation of case: A 20-year-old female patient was presented with an upper abdominal pain and dyspepsia since 2 months duration.This case  is initially thought as GIST but finally diagnosed as vagal nerve schwannoma by histopathological evaluation after resection of the mass.Conclusion: Schwannomas should be considered in the differential diagnosis of other mesenchimal tumors, such as gastrointestinal stromal tumors and leiomyomas or leiomyosarcomas, indeed it can grow in any part of the peripheral nerves along the gastrointestinal tract. Histopathological evaluation including immunohistochemical staining is required for the definitive diagnosis

Efficiency analysis of induction air heater and investigation of distribution of energy losses

U ovom se radu analizira prototip indukcijskog grijača zraka konstruiranog za dovod higijenskog zraka. Cilj je rada odrediti raspodjelu gubitaka energije i ispitati učinke diskova na toplinsku učinkovitost prototipa. Analiza je provedena primjenom prvog zakona termodinamike. U radu su izračunati i prezentirani gubici zbog prirodne konvekcije i zračenja, gubici ispuštanja i gubici zbog kinetičke energije. Izračunato je da je maksimalna toplinska učinkovitost 29,9 % bez diskova. Ustanovljeno je da, kako bi se osigurala konkurentnost indukcijskih grijača zraka u odnosu na druge grijače, toplinska učinkovitost se može povećati do 90 % odgovarajućom izolacijom i konstrukcijom. Ustanovljeno je da primjena diskova smanjuje učinkovitost i ukupni se gubitak energije smanjio smanjenjem broja diskova.In this study, an induction air heater prototype that is designed to supply hygienic air was analysed. The purpose of this paper is to determine the distribution of energy losses and investigate the effects of inducer discs on the thermal efficiency of the prototype. The analysis was carried out by applying the 1st Law of Thermodynamics. In the study, the natural convection and radiation losses, the discharge losses and the losses due to kinetic energy were calculated and presented. The maximum thermal efficiency was calculated to be 29,9 % without discs. It was seen that, to ensure the competitiveness of the induction air heater among other air heaters, the thermal efficiency can be boosted up to 90 % with appropriate insulation and construction. It was seen that utilizing the discs decreased the efficiency and the total energy loss was reduced as the number of discs was decreased

Analysis of efficiency of tunnel type induction furnace inductors with respect to variation of diameter of heated workpiece

UNVER, Umit/0000-0002-6968-6181WOS: 000427552600013In this study, calculations of net efficiency of heating process of aluminum billets those diameters are different from the diameter of the inductor were aimed. The targeted aluminum extrusion facilities utilize induction furnaces. In the heating experiments, an induction coil that was designed to heat circle divide 178 mm aluminum billets was used. The discs diameters are in accordance with the standard billet diameters. Additionally, a computer simulation of induction heating of discs was performed and the results were evaluated. It was observed that concentric or eccentric location of discs in the inductor induces an increment in the disc temperature and electrical power consumption and contrarily does not affect the heating efficiency. Therefore, it was determined that there is no need to construct some additional mechanisms to supply concentric location of the billet in the inductor. Finally, a user friendly efficiency scale function was obtained for the circle divide 178 mm inductor which is used for heating different diameter billets than the inductors design diameter

Introduction of a Novel Design Approach for Tunnel-Type Induction Furnace Coil for Aluminium Billet Heating

UNVER, Umit/0000-0002-6968-6181; KELESOGLU, Alper/0000-0001-7139-6653WOS: 000425983400006In this paper, a user-friendly algorithm was developed by analysis of induction heating of aluminium in a radial direction using analytic, numerical and experimental methods. The aim of this study was to investigate the design data required for the coil and the power supply. The mathematical model of the heating process was simplified into one dimension. The general equation of heat conduction was solved analytically in cylindrical coordinates. The results are validated with the results of experimental and numerical methods. In the study, it is seen that the radial temperature distribution can be modelled with a second-degree equation with a 7% error rate. An important benefit of this paper is the homogenization time coefficient that is a useful tool for calculating the total resting time. Finally, a basic and user-friendly method was described to investigate the length of a tunnel-type induction furnace coil design.Kirikkale University Scientific Studies Coordination Unit [2014/057]This study was granted by Kirikkale University Scientific Studies Coordination Unit with the Project No: 2014/057. We also gratefully thank to Mr. I. Muzaffer UNVER and Mr. Lenny CRAGG for their valuable supports

Analysis of a novel high performance induction air heater

UNVER, Umit/0000-0002-6968-6181; KELESOGLU, Alper/0000-0001-7139-6653WOS: 000441484700007This study represents an experimental and numerical investigation of the enhanced prototypes of the induction air heaters. For this purpose, flow field is enhanced in order to avoid turbulence. The air mass flow rate, outlet construction and the application of insulation of the outer surface of the heater were selected as the performance enhancing parameters. Depending on the exit construction, the new designed prototypes are named as K-2 and K-3. Experiments were performed under two groups for three various flow rates. In the first group, non-insulation situation is examined. In the second group tests, insulation is applied to the outside of windings and inlet-outlet flaps which constitute the boundary of the control volume for the prevention of heat losses. The increasing flow rate boosted the thermal efficiency by 9%. Each of insulation and enlarging exit cross section increased the thermal efficiency by 13%. It was observed that the thermal power transferred to air with the new prototypes increased about 246 W more than the previous designs. The thermal efficiencies of the K-2 and K-3 type heaters were calculated as 77.14% and 87.1%, respectively.University of Yalova Scientific Research Coordination Unit [2015/YL/059]This study was granted by University of Yalova Scientific Research Coordination Unit with the Project No:2015/YL/059. We would like to thank I. Muzaffer UNVER from KEMAS Co. and Mehmet OZDESLIK from Sistem Teknik Co. for their valuable contributions in this study

A novel method for prediction of gas turbine power production: Degree-day method

Gas turbines are widely used in the energy production. The quantity of the operating machines requires a special attention for prediction of power production in the energy marketing sector. Thus, the aim of this paper is to support the sector by making the prediction of power production more computable. By using the data from an operating power plant, correlation and regression analysis are performed and linear equation obtained for calculating useful power production vs atmospheric air temperature and a novel method, the gas turbine degree day method, was developed. The method has been addressed for calculating the isolation related issues for buildings so far. But in this paper, it is utilized to predict the theoretical maximum power production of the gas turbines in various climates for the first time. The results indicated that the difference of annual energy production capacity between the best and the last province options was calculated to be 7500 MWh approximately

Analysis of a novel high performance induction air heater

This study represents an experimental and numerical investigation of the enhanced prototypes of the induction air heaters. For this purpose, flow field is enhanced in order to avoid turbulence. The air mass flow rate, outlet construction and the application of insulation of the outer surface of the heater were selected as the performance enhancing parameters. Depending on the exit construction, the new designed prototypes are named as K-2 and K-3. Experiments were performed under two groups for three various flow rates. In the first group, non-insulation situation is examined. In the second group tests, insulation is applied to the outside of windings and inlet-outlet flaps which constitute the boundary of the control volume for the prevention of heat losses. The increasing flow rate boosted the thermal efficiency by 9%. Each of insulation and enlarging exit cross section increased the thermal efficiency by 13%. It was observed that the thermal power transferred to air with the new prototypes increased about 246 W more than the previous designs. The thermal efficiencies of the K-2 and K-3 type heaters were calculated as 77.14% and 87.1%, respectively

Analysis of the effect of construction parameters on energetic and exergetic efficiency of induction air heaters

KELESOGLU, Alper/0000-0001-7139-6653; UNVER, Umit/0000-0002-6968-6181WOS: 000428177300005This study is concerned with the energy and exergy efficiency analysis of a novel air heater that operates with induction principle. The aim of this paper is investigation of the energy and the exergy efficiency augmentation of the new K-1 induction air heater prototype. Energy and exergy performance of the K-1 prototype was analysed and compared with the previous K-0 prototype. The analyses were performed with experimental study and with computational fluid dynamics (CFD) simulations. The new design boosted the energy efficiency about 22.98%. The exergy efficiency was calculated to be around 11.5% max. The CFD simulation results showed that a 1 m/s increase in the inlet velocity yields 3.1% and 0.06% augmentation in the energy and the exergy efficiency respectively. The inlet temperature increase negatively affects the energy and the actual exergy efficiencies. It was concluded that efficiencies of these heaters can be enhanced with more appropriate construction

Design of a passive rainwater harvesting system with green building approach

In this study, a passive rainwater harvesting system was designed. The system is planned to be installed on the roof of the building of Engineering Faculty of Yalova University. The meteorological rain data of Yalova province was analysed and the most suitable rainwater silo dimensions were determined accordingly. A suitable location for the silo was recommended considering the statics of the building. The passive rainwater harvesting system requires no additional pump power and no complex filtration systems. A rainwater delivery system is designed from the roof to the reservoirs for flushing without any additional energy consumption according to the storage location. The minimum height between the tank and the floor was determined to compensate the pressure losses along the critical length. The results of the economic analysis showed that this system can save about 8.5 tons of water/year and 2900 €/year water costs from one building

Objective analysis of voice changes in a hemodialysis session and its correlation with ultrafiltration

WOS: 000350554300017PubMed ID: 25457372Introduction: The aim of the study is to analyze the voice changes occurring during a hemodialysis session objectively and to investigate the statistical correlation between voice changes and ultrafiltration, blood pressure, dry weight and the other variables of the patients. Materials and methods: A total of 169 patients were included in the study. Electronic voice recordings of the patients were performed with the aim of making objective voice analysis before and after dialysis. Fundamental frequency measurements occurring at the level of the larynx (Fo) and harmonic-to-noise ratio (HNR) were measured from these voice recordings. Results: When the voice recordings obtained from 169 hemodialysis patients before and after dialysis were investigated, it was observed that a significant increase occurred in the Fo (from 164.52 +/- 43.36 Hz to 193.19 +/- 47.08 Hz, p < 0.01). When the change in HNR was investigated, a significant reduction was determined in the post-dialysis measurements (4.6 +/- 3.23 dB) compared to the pre-dialysis measurements (16.10 +/- 4.06 dB, p < 0.01). Mean 2.49 +/- 0.83 L of ultrafiltration was performed and a significant reduction was observed in post-session body weights of the patients (p < 0.01). There was a highly statistical significance between the measurements of post-dialysis Fo and post-dialysis body weights. A highly significant correlation was determined between the amount of ultrafiltration performed and a significant increase observed in Fo before and after dialysis. Also a significant correlation was determined between the reduction in the mean post-session blood pressures and the reduction in the HNRs. Conclusion: Objective voice analysis is suggesting that it can be a simple and applicable method that can be used to determine the dry weight