Shell models and the possibility of application to fusion plasmas

Gü,rcan, Ö,D,Hennequin, P,Vermare, L,Garbet, X,Diamond, P H Published jointly by The Institute of Physics and 2010 Plasma physics and controlled fusion Vol.52 No.4

<P>An extensive study of spectral shell models with possibilities for application to fusion plasmas is discussed. A set of shell models addressing various aspects of the characteristics of fusion plasmas have been derived. Difficulties associated with plasma medium, namely its intrinsic excitability, and importance of mescals have been discussed. The numerical implementation of shell models is discussed. It was observed that depending on the parameter regime, they may lead to steady state or display characteristics of predator–prey dynamics.</P>

Intrinsic non-inductive current driven by ETG turbulence in tokamaks

Singh, Rameswar,Kaw, P. K.,Singh, R.,Gü,rcan, Ö,. D. American Institute of Physics 2017 Physics of plasmas Vol.24 No.10

Investigation of the performance of a thermoelectric generator system utilizing the thermal energy of air compressed in a compressor

Gürcan Ali,Yakar Gülay 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.6

The present study includes a numerical analysis on the electrical power output of a thermoelectric generator system placed between a compressor and the intercooler of a turbocharged tractor. Although current literature already includes reports on thermal energy of exhaust gases used by thermoelectric generators in automobiles, this study is oriented on the utility of the thermal energy of the compressed outlet air from the compressor by the thermoelectric generators. This is the uniquness of the present study. Numerical results showed that the highest and the lowest performances occurred at outdoor temperatures of 268 K and 303 K, respectively. From a single thermoelectric module, while a 1.23 W power output was obtained at outdoor temperature of 268 K, a 0.7 W power output was obtained at 303 K. The thermoelectric generator system used in this study consisted of 28 thermoelectric generator modules. The power output generated by this system can be used for any electrically powered devices on a tractor, such as a tractor refrigerator with a thermoelectric cooler whose power requirement can be easily satisfied by using the thermoelectric generator system. In a turbocharged tractor with a thermoelectric generator, the temperature of the air entering into the intercooler for a single thermoelectric generator module was decreased by 1.6% at an outdoor temperature of 268 K in comparison with the one without the thermoelectric generator.

Densification and properties of in-situ synthesized ZrB2- SiC composities from ZrO2, B4C and SiC system

Kübra Gürcan 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.4

Zirconium diboride-silicon carbide (ZrB2-SiC) ceramics were in-situ synthesized and densified by the spark plasma sintering(SPS) method using ZrO2, B4C and SiC as starting powders. Both synthesis and densification processes were successfullyaccomplished in a single SPS cycle with one step heating schedules which were designed by considering thermodynamiccalculations made by Factsage software. One step synthesis/densification schedule at 1950 oC with a 30 min hold time under50 MPa uniaxial pressure lead to obtain ZrB2-SiC ceramics up to 93% of its theoretical density. Considering the literature,low hardness values (max. 17.55 GPa) were achieved which were directly attributed to the low bonding between ZrB2 and SiCgrains in terms of the residual stresses occurred during the synthesis and cooling steps. Fracture toughness of the ceramics was4.12 MPa.m1/2 and crack deflection and microcracking were believed to be primary toughening mechanisms of ZrB2-SiCcomposites.

Effects of pretreatments on seed dormancy and germination in endemic Uludağ flax (Linum olympicum Boiss.) (Linaceae)

Serap Kırmızı,Gürcan Güleryüz,Hülya Arslan 한국원예학회 2018 Horticulture, Environment, and Biotechnology Vol.59 No.5

Linum olympicum Boiss. (Linaceae) is an endemic species to Turkey, and has both medicinal and ornamental properties. In this study, we investigated the effects of GA3 and cold stratification (1 or 4 months) on the germination and mean germination time in relation to breaking dormancy in this species under darkness (20 °C) and light (20/10 °C, 12/12 h) conditions. Seeds were collected from specimens that spread on limestone or granite screes, ledges of rocky or turfy slopes, and hilltops of the alpine belt from Uludağ Mt. (Bursa, Turkey, 2200–2300 m). We show that a combination of hormone and cold stratification treatments promoted seed germination under darkness and light conditions. Non-stratified seeds germinated to 73% following 1000 mg L−1 GA3 treatment and also it was 83% after 1 month cold stratification. After 4 months of cold stratification treatment, 10% and 53.3% of seeds successfully germinated after incubation in light and dark conditions, respectively. Hormone and cold stratification treatments also reduced mean germination time. Our results revealed that seeds of L. olympicum have physiological dormancy and require prolonged time for cold stratification and darkness for germination, rather than responding to the photoperiod. Germination requirements of L. olympicum have not been studied previously, and the data obtained could be used for the ex situ protection of this alpine species.

Carrying Capacity in Terms of the Sustainable Tourism : A Case in Saint Nicholas Museum in Myra-Demre

Ahmet AKTAŞ,Şeyla DEMİRCAN 세계문화관광학회 2011 Conference Proceedings Vol.12 No.-

In the archeological cultural inventory of Antalya Governorate a lot of religious structure remains were identified in Demre and Saint Nicholas Church is the cathedral. Nowadays the area known as Saint Nicholas Museum is visited especially from May to October during the DMK one day tours. Tourism implementer's aim of drawing tourists can pass over the carrying capacity of that district or area. The main goal of our study is to draw attention to the problems about carrying capacity which is faced in touristic areas and substantially affects sustainable tourism. In our study it was tried to obtain data to determine the relation between the density of visitors of the (Father Christmas Museum) Saint Nicholas Church in Demre and the carrying capacity of the area. The study includes the guides registered to Antalya Tourist Guides Guild. The questionnaire survey which was used to collect data was applied to 163 guides who were chosen by simple random sampling. Data analysis was done by SPSS 13.0 and t test and Anova test were used. Through a training program for guides which focuses on Saint Nicholas and the religious edifice remains from Demre the narrations and messages of the guides leading tours in the area should harmonize with the cultural tourism policy of the administration and should get the best out of belief tourism.

Portal Hypertension in Children: A Tertiary Center Experience in Turkey

Emine Nur Sunar Yayla,Sinan Sarı,Neslihan Gürcan Kaya,Ödül Eğrİtaş Gürkan,Hakan Sözen,İbrahim Onur Özen,Aydın Dalgıç,Buket Dalgıç 대한소아소화기영양학회 2023 Pediatric gastroenterology, hepatology & nutrition Vol.26 No.6

Purpose: Portal hypertension (PH) and its complications have a significant impact on morbidity and mortality. This study aimed to evaluate the etiology; clinical, laboratory, and endoscopic findings; treatment approaches; long-term outcomes; and prognosis of pediatric PH. Methods: This retrospective study included 222 pediatric patients diagnosed with PH between 1998 and 2016, and data encompassing clinical, laboratory, and radiological features; treatments; and complications were analyzed. Results: The most common causes of PH were portal vein thrombosis (20.3%), progressive familial intrahepatic cholestasis (18.9%), and biliary atresia (12.2%). Among the enrolled patients, 131 (59.0%) were included in the cirrhotic group and 91 (41.0%) in the noncirrhotic group. Hepatomegaly and increased transaminase levels were more frequent in the cirrhotic group than in the non-cirrhotic group. Additionally, portal gastropathy, esophageal varices, and variceal bleeding were more frequent in the non-cirrhotic group, whereas ascites, hepatopulmonary syndrome and hepatic encephalopathy were more common in the cirrhotic group. The incidence of hepatomegaly was higher in the presinusoidal group than in the prehepatic group (p<0.001). Hyperbilirubinemia was more frequent in the prehepatic group (p=0.046). The frequency of esophageal varices was similar between the prehepatic and presinusoidal groups; however, variceal bleeding was more frequent in the prehepatic group (p=0.002). Conclusion: Extrahepatic portal vein obstruction, genetic-metabolic diseases, and biliary atresia were the most prevalent causes of PH in our country. In patients with PH, hepatomegaly, increased transaminase levels, and synthesis dysfunction were suggestive of cirrhotic PH. Notably, PH in patients without cirrhosis might be more severe than that in those with cirrhosis.