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Akay A.N.,TOBB University of Economics and Technology | Karadeniz H.,Turkish Atomic Energy Authority | Sultansoy S.,TOBB University of Economics and Technology | Sultansoy S.,Azerbaijan Academy of Sciences
International Journal of Modern Physics A | Year: 2010

There are three possible types of particle colliders schemes: familiar (well-known) ringring colliders, less familiar but sufficiently advanced linear colliders, and less familiar and less advanced linacring-type colliders. The aim of this paper is twofold: to present a possibly complete list of papers on linacring-type collider proposals and to emphasize the role of linacring-type machines for future HEP research. © 2010 World Scientific Publishing Company.

Turhan T.,University of Nevsehir | Kose A.,Cekmece Nuclear Research and Training Center | Varinlioglu A.,Cekmece Nuclear Research and Training Center | Sahin N.K.,Ankara Nuclear Research And Training Center | And 4 more authors.
Geoderma | Year: 2012

A comprehensive study was executed to determine the distribution of the natural and anthropogenic radionuclides in surface soils throughout Turkey. In this study, the activity concentrations of 238U, 232Th, 40K and 137Cs in total of 1031 soil samples collected from seven geographical regions of Turkey were measured using the high-resolution gamma spectrometer with HPGe detector. The activity concentrations of 238U, 232Th, 40K and 137Cs in soil samples varied from 2.0 to 220.0Bqkg -1 with a mean of 28.6±0.7Bqkg -1, 1.0 to 158.6Bqkg -1 with a mean of 33.0±0.7Bqkg -1, 26.0 to 1603.2Bqkg -1 with a mean of 448.5±7.3Bqkg -1 and 1.0 to 357.0Bqkg -1 with a mean of 13.4±0.8Bqkg -1, respectively. Elemental concentration mean values of 238U, 232Th and 40K were found as 2.3mgkg -1, 8.1mgkg -1 and 1.4%, respectively. For all surface soil samples the absorbed gamma dose rate and the corresponding effective dose rate due to the external exposure in outdoor were evaluated as 51.9 nGy h -1 (4.7-234.3 nGy h -1) and 0.064mSv y -1 (0.006-0.287mSv y -1), respectively. © 2012 Elsevier B.V.

Kocmen M.A.,Turkish Atomic Energy Authority | Tegmen A.,Ankara University | Tureci D.,75. Yil Anadolu Lisesi | Gulecyuz M.C.,Ankara University | Tureci R.G.,Kirikkale University
Kerntechnik | Year: 2013

The half-space albedo problem and the constant source problem have been solved for a combination of the linearly anisotropic scattering and İnönü's scattering functions. The linear transport equation for extremely anisotropic scattering kernel can be converted into an equivalent equation with a linearly anisotropic scattering kernel and the modified F N method can be used for albedo calculations. © Carl Hanser Verlag, München.

Saglar E.,Hacettepe University | Unlu S.,Turkish Atomic Energy Authority | Babalioglu I.,Ankara University | Gokce S.C.,Ankara University | Mergen H.,Hacettepe University
Journal of Biochemical and Molecular Toxicology | Year: 2014

Acute radiation leads to several toxic clinical states and triggers some molecular pathways. To shed light on molecular mechanisms triggered by ionizing radiation (IR), we examined the expression profiles of endoplasmic reticulum (ER) stress and autophagy-related genes in individuals who were exposed to IR. Blood samples were collected from 50 cancer patients before radiotherapy and on the 5th, 15th, and 25th days of the treatment. Peripheral blood samples from 10 healthy volunteers were also obtained for ex vivo irradiation, divided into five and irradiated at a rate of 373 kGy/h to 0, 0.1, 0.5, 1, and 3Gy γ-rays using a constant gamma source. GRP78, ATG5, LC3, ATF4, XBP1, and GADD153 genes were analyzed by quantitative real-time polymerase chain reaction (QRT-PCR) using beta 2 microglobulin (B2M) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as references. In both groups, expressions of the selected genes have increased. It can be concluded that IR induces ER stress and related authophagy pathway in the peripheral lymphocyte cells proportionally by dose. © 2014 Wiley Periodicals, Inc.

Bulut S.,Ankara Nuclear Research And Training Center | Celenk I.,Ankara Nuclear Research And Training Center | Artan S.,Turkish Atomic Energy Authority
Kerntechnik | Year: 2013

The application of numerical codes is well established in the regulatory practice for nuclear power plants. Therefore, requirements for computer-aided analyses can be found in different places of the nuclear technical rules and standards. These requirements also apply for CFD analyses which reached more and more the spot light of research activities and component design, because computing capacities increased significantly in the past years. Hence, the actual status of CFD as a possible design and analysis tool in the supervising process of nuclear power plants will be discussed in this paper. The focus is set on the prerequisites which have to be fulfilled by codes and in particular by the user who wants to use CFD methods. The prerequisites will be derived directly from the existing German technical rules and standards. Finally, two examples for typical CFD applications for nuclear safety analyses are given. © Carl Hanser Verlag München.

Kocmen M.A.,Turkish Atomic Energy Authority | Oncu T.,Turkish Atomic Energy Authority | Oncu T.,Hacettepe University
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2013

The effects of interfacial insulator layer on the electrical characteristics of Al/p-Si diodes have been investigated using the current-voltage (I-V) characteristics at room temperature. The values of ideality factor (n), barrier height (Øb) and series resistance Rs have been determined from ln(I)-V plots, Cheung functions and the modified Norde functions. Electrical properties obtained from I-V characteristics of the device with interfacial insulator layer have been compared with the ones obtained from I-V characteristics of the device without interfacial insulator layer. The calculated ideality factor and barrier height are 1.49 and 0.595 eV for Al/p-Si diode, and 1.94 and 0.517 eV for Al/SiO2/p-Si diode, respectively, and it is observed that the ideality factor (n) increases and barrier height (Øb) decreases with interfacial insulator layer. The series resistance values obtained from Cheung functions of the diode with and without the interfacial insulator layer are Rs= 71 Ω and Rs= 112 Ω, respectively. Current-voltage characteristics and the power-law dependence was determined to be governed by space charge-limited currents (SCLC).

Deger C.,Marmara University | Ozdemir M.,Turkish Atomic Energy Authority | Yildiz F.,Kocaeli University
Journal of Magnetism and Magnetic Materials | Year: 2016

Behavior of spin waves was investigated in patterned Mu-metal thin film both theoretically and experimentally. The Mu-metal(111) thinfilms with 7 nm thickness were grown by thermal evaporation technique in high vacuum condition. X-ray diffraction measurements showed that the film has a highly FCC crystalline structure. Saturation magnetization and coercive field values of sample obtained from vibrating sample magnetometer are around 500 emu/cm3 and 10 Oe respectively at room temperature. The patterns were square shaped and size of squares were changed between 40-80 μm. Theoretical model and computer program were developed for analyzing the FMR spectra. There is no magnetic anisotropy for in-plane and out-of-plane geometry by both theoretical and experimental investigations. Magnetostatic modes were observed for out-of-plane geometry and these modes were highly compatible with outputs of simulation model. © 2016 Elsevier B.V.

Turhan S.,Turkish Atomic Energy Authority | Parmaksiz A.,Ankara Nuclear Research And Training Center | Kose A.,Ekmece Nuclear Research and Training Center | Yuksel A.,Ekmece Nuclear Research and Training Center | And 2 more authors.
Fuel | Year: 2010

The objective of this study is to determine radiological characteristics of pulverized fly ash (PFA) collected from the 15 coal-burning thermal power plants (TPPs) in operation by means of gamma spectrometric technique and to assess the radiological impacts from the utilization of PFA samples examined as filling and cover material in earthwork applications. Also, the annual effective doses received by workers handling PFA and members of the public living in a house near the PFA pile/landfill were estimated using methods specified in the Radiation Protection 122. The activity concentrations of 226Ra, 232Th and 40K measured in PFA samples were tabulated for each TPP. The activity results show that Turkish PFA may have relatively high natural radioactivity content, depending on its origin reaching in the case of Kangal PFA 2720 Bq kg-1 of 226Ra. The values of external exposure indexes (radium equivalent activity index and gamma index) calculated for PFA samples are within the recommended safety limits. As well, the highest mean total annual effective doses estimated as 7.3 × 10-5 Sv y-1 for workers and 1.5 × 10-4 Sv y-1 for members of the public are significantly lower than the annual limit of 1.0 × 10-3 Sv y-1. © 2010 Elsevier Ltd. All rights reserved.

This study has been performed to assess the condensation module of RELAP5/MOD3.3 code, which is still widely used in the nuclear industry, for in-tube condensation in the presence on noncondensable gas under forced convection conditions. The experimental works, conducted at the Massachusetts Institute of Technology (MIT), the University of California-Berkeley (UCB), and the Middle East Technical University (METU), have been utilized in order to realize the assessment process in the wide range of parameters. To investigate the relationship between mixture Reynolds number and interface temperature, the theoretical model based on the energy balance at the interface has been developed and the results have been compared with the RELAP5/MOD3.3 findings. The entrance, interfacial waviness, suction and interfacial shear stress effects have been considered in the modeling to obtain accurate estimation of the heat transfer coefficient, particularly at the entrance region. The comparisons show that the proposed model predicts the heat transfer coefficient reasonably well with a maximum mean deviation of 17.3% for the simulated cases. On the other hand, RELAP5/Mod3.3 cannot evaluate the relationship between the mixture Reynolds number and the interface noncondensable gas concentration and predicts the heat transfer coefficients with the mean deviations around 150%, 85% and 50% for the METU, the UCB and the MIT databases, respectively. The findings reveal that the RELAP5/MOD3.3's capability to simulate the condensation with noncondensable gas phenomenon drastically decreases with increasing mixture Reynolds number. © 2013 Elsevier Ltd. All rights reserved.

Can S.,Kocaeli University | Karsli N.G.,Kocaeli University | Yesil S.,Turkish Atomic Energy Authority | Aytac A.,Kocaeli University
Journal of Polymer Engineering | Year: 2016

The main aim of this study was to improve the mechanical properties of the recycled poly(ethylene terephthalate)/poly(ethylene 2,6-naphthalate) (r-PET/PEN) blends by enhancing the miscibility between PET and PEN with the usage of chain extenders. This idea was novel for the recycled PET-based r-PET/PEN blends, as investigation of the effects of the chain extender usage on the properties of r-PET/PEN blends has not been studied in the literature, according to our knowledge. 1,4-Phenylene-bis-oxazoline (PBO), 1,4-phenylene-di-isocyanate (PDI), and triphenyl phosphite (TPP) were selected as chain extenders. The maximum tensile strength value was observed for the 1.0PDI sample. Moreover, PDI-based blends exhibited better Izod impact strength when compared with all other samples. The miscibility and degree of crystallinity values of all blends were discussed by means of thermal analysis. 1H-nuclear magnetic resonance (1H-NMR) analysis was carried out to determine transesterification reaction levels. According to 1H-NMR results, the increase in the level of transesterification was around 40% with the usage of PDI. The optimum loading level for selected chain extenders was determined as 1 wt.%, and PDI-based blends exhibited better properties when compared with those of the blends based on PBO and TPP at this loading level. © 2016 Walter de Gruyter GmbH, Berlin/Boston 2016.

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