Diyarbakr, Turkey
Diyarbakr, Turkey

Dicle University is a public university located on eastern side of the Tigris river. The university is one of the oldest and largest higher education institutions in southeastern Anatolia, Turkey.Built on a twenty-seven-thousand-acre area in the eastern side of the historical city of Diyarbakır, Dicle University takes its name from the river which splits the university from the city. Apart from its main campus in Diyarbakır, the university has vocational schools in counties like Ergani, Çermik, Çüngüş, Bismil, and Silvan. Wikipedia.

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Ocak Y.S.,Dicle University
Journal of Alloys and Compounds | Year: 2012

ZnO thin films were formed on a p-Si semiconductor and a glass by DC sputtering technique. The ZnO films were analyzed using UV-vis spectroscopy and X-ray diffraction (XRD). Electrical and photoelectrical parameters of ZnO/p-Si heterojunction were determined by current-voltage (I-V), capacitance-voltage (C-V) and capacitance-frequency (C-f) of the device in dark and under the light with 100 mW/cm 2 and AM 1.5 illumination property. The device had a good rectifying property with 1.35 ideality factor, 0.76 eV barrier height and 6.69 kΩ series resistance values. It was seen that I-V, C-V and C-f measurements of the heterojunction had good sensitivity to the light and the device behaves as a photodiode and a photocapacitor. © 2011 Elsevier B.V. All rights reserved.

Ozer S.Y.,Dicle University
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology | Year: 2011

Objective The purpose of this study was to compare the shaping ability (apical transportation and straightening) of 3 nickel-titanium rotary instruments (ProTaper Universal, Hero 642 Apical, FlexMaster) with noncutting tips in curved root canals of extracted human teeth using cone beam computed tomography (CBCT). Study design Sixty mesiobuccal root canals of maxillary molars with curvatures of 25° to 47° were equally divided into 3 groups and embedded in silicone impression material. The root canals were scanned using CBCT (Next Generation i-CAT) and after scanning working length was determined with a hand file to preserve the original curvature. After preparation, teeth were placed into their original positions on the silicone impression material and postinstrumentation scans were performed using the same parameters (4-cm field of view at 0.125-mm voxel). Pre- and postinstrumentation images obtained from root cross-sections located 2, 3, and 4 mm above the apical foramen were compared using Adobe Photoshop software. Transportation was measured by superimposition of final and initial images. Any distance (mm) between prepared and anatomic canal centers was defined as apical transportation. Canal curvatures were measured before and after instrumentation using computed tomography and images were exported to ImageJ software. Differences in the degree and radius of curvature were regarded as straightening. Data were analyzed by ANOVA. Results Mean transportation values were 0.10 ± 0.03 mm for ProTaper Universal, 0.09 ± 0.03 mm for Hero 642 Apical, and 0.07 ± 0.02 mm for FlexMaster, and the differences were not significant. Mean values for straightening among the groups were not significantly different (P > .05). The performances of all instruments were similar. Conclusion Apical transportation occurred with all the instruments despite their noncutting tips. © 2011 Mosby, Inc. All rights reserved.

Fifty-five samples of asphaltites from 12 different veins in irnak area and two oil samples from Raman and Diner Oil fields in South East (SE) Turkey have been analyzed by organic geochemical methods (total organic carbon, rock-eval pyrolysis, gas chromatography of saturated fractions, gas chromatography-mass spectrometry and stable carbon isotope). The total organic carbon (TOC) contents in asphaltites ranged from 12% to 65%. The Tmax values range between 428 °C and 465 °C. The hydrogen index (HI) values vary between 270 and 531 mg HC/g TOC. The levels of biodegradation of the asphaltites were studied by GC analyses of the saturated fractions and none to moderate biodegradation has been found. Maturity of the asphaltite samples were assessed biomarker ratios provided by GC-MS analysis. Stable carbon isotope (13C) analyses of Raman-Diner oils produced values about -27‰ and the asphaltene fractions of the asphaltite samples revealed similar values about 26.8‰. It is presumed that the asphaltites are of oil origin and has been solidified in veins close to surface and the geochemical correlation and encountering to the oil seeps in crevices suggest similarities between the irnak area asphaltites and Raman-Diner oils. © 2011 Elsevier Ltd All rights reserved.

Karakus A.,Dicle University
Construction and Building Materials | Year: 2011

Stone Mastic Asphalt (SMA) improved for road construction which has been utilized in Europe and America for 40 years is a rather new process in Turkey. SMA basically consists of 93-94% aggregate and mineral fillers, 6-7% bitumen and additives. Road and construction industry consume stone in large amounts. Stone used are obtained from nearby quarries and carried to the location where they are to be used, destroying the nature and causing large costs. The constantly increasing demand on quarries harms the general structure of the earth thus causing the emergence of large scale environmental problems. The use of basalt waste from stone processing plants as aggregates and mineral filler in SMA might help to meet this increasing demand thus solving environmental problems. In this study, primarily some important material properties of fine and coarse basalt waste, taken from basalt processing plants in Diyarbakir, such as sieve analysis, chemical analysis, specific gravity, water absorption, Los Angeles abrasion loss value, soundness of aggregate by Na2SO4, flakiness index and stripping strength were determined. Then by using this waste material, a SMA was designed according to Turkish Highway Technical Specifications. Marshall stability and flow tests have been carried out on designed SMA specimens. Test results indicate that properties of the basalt waste and the SMA produced were within the specified limits and that these waste materials can be used as aggregates and mineral filler in SMA. © 2011 Elsevier Ltd. All rights reserved.

Ozler A.,Dicle University
European review for medical and pharmacological sciences | Year: 2012

There are many studies evaluating the role of inflammation in the pathogenesis of preeclampsia. However, little is known about the relationship between the severity of inflammation and the severity of preeclampsia due to insufficient of studies reporting this matter. To investigate the maternal serum concentrations of IL-6, TNF-alpha and Neopterin in patients with mild preeclampsia and severe preeclampsia and HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome in preeclampsia and determine their association with the severity of the disease. Patients, hospitalized with the diagnosis of preeclampsia between October 2011 and March 2012, were included in the study. The patients with preeclampsia were divided into three groups as mild preeclampsia, severe preeclampsia and HELLP syndrome. The control group was comprised of normotensive and uncomplicated pregnant women. The serum levels of IL-6, TNF-alpha and Neopterin (NEO) were determined, using enzyme-linked immunosorbent assay. Spearman's rank correlation tests were used for the correlations between the serum levels of inflammatory markers and the severity of preeclampsia. There was no observed significant difference among mean serum TNF-alpha and IL-6 levels of four groups (p > 0.05). The median serum concentration of NEO in subjects with mild preeclampsia of 14.1 nmol/L and severe preeclampsia of 14.8 nmol/L was significantly higher than that of 10.3 nmol/L in normotensive controls (p = 0.013; p = 0.000 respectively). In addition, the median serum concentration of NEO was detected to be highest in subjects with HELLP syndrome. The serum levels of NEO was well correlated with the severity of preeclampsia (r = 0.533, p = 0.000). The serum levels of NEO, an important marker of cellular immunity, associated with severity of disease in patients with preeclampsia.

Salti M.,Dicle University
International Journal of Theoretical Physics | Year: 2013

The main goal of the present work is to investigate the validity of the second law of gravitational thermodynamics in an expanding Gödel-type universe filled with generalized Chaplygin gas interacting with cold dark matter. By assuming the Universe as a thermodynamical system bounded by the apparent horizon, and calculating separately the entropy variation for generalized Chaplygin gas, cold dark matter and for the horizon itself, we obtained an expression for the time derivative of the total entropy. We conclude that the 2nd law of gravitational thermodynamics is conditionally valid in the cosmological scenario where the generalized Chaplygin gas interacts with cold dark matter. © 2013 Springer Science+Business Media New York.

Oruc V.,Dicle University
Journal of Fluids and Structures | Year: 2012

The results of PIV measurements are presented in this paper for the water flow downstream of a circular cylinder surrounded with a screen (meshed outer control element) which had a streamlined shape. The diameter of cylinder, D was 50. mm and the Reynolds number based on the cylinder diameter was 5200. The characteristic length of the control element, L was tested for different cases so that the values of L/. D were 2, 2.4, 2.8 and 3.2 in the experiments. It was noted that a forced reattachment of the shear layers separated from the cylinder was achieved by setting up the screen around the cylinder. As a consequence, the formation of vortical flow pattern was suppressed and turbulence statistics of the flow such as the intensity of turbulence, Reynolds shear stress, and turbulent kinetic energy were drastically diminished in comparison to the bare cylinder case. It was also found that the variable parameter of L/. D did not dominantly influence the characteristics of the distribution of turbulence statistics along streamwise and transverse directions, however, the turbulence level decreased slightly for a smaller case of L/. D. © 2012 Elsevier Ltd.

Kilickap E.,Dicle University
Expert Systems with Applications | Year: 2010

Drilling of glass fibre reinforced plastic (GFRP) composite is substantially different from metallic materials due to its mechanical properties. The drilling of this material may generate delamination of drilled holes on workpiece. The purpose of this paper is to investigate the influence of the cutting parameters, such as cutting speed and feed rate, and point angle on delamination produced when drilling a GFRP composite. The damage generated associated with drilling GFRP composites were observed, both at the entrance and the exit during the drilling. Hence it is essential to obtain optimum cutting parameters minimizing delamination at drilling of GFRP composites. Moreover, this paper presents the application of Taguchi method and analysis of variance (ANOVA) for minimization of delamination influenced by drilling parameters and drill point angle. The optimum drilling parameter combination was obtained by using the analysis of signal-to-noise ratio. The conclusion revealed that feed rate and cutting speed were the most influential factor on the delamination, respectively. The best results of the delamination were obtained at lower cutting speeds and feed rates. © 2010 Elsevier Ltd. All rights reserved.

Kilickap E.,Dicle University
International Journal of Advanced Manufacturing Technology | Year: 2010

This investigation presents the use of Taguchi and response surface methodologies for minimizing the burr height and the surface roughness in drilling Al-7075. The Taguchi method, a powerful tool to design optimization for quality, is used to find optimal cutting parameters. Response surface methodology is useful for modeling and analyzing engineering problems. The purpose of this paper was to investigate the influence of cutting parameters, such as cutting speed and feed rate, and point angle on burr height and surface roughness produced when drilling Al-7075. A plan of experiments, based on L 27 Taguchi design method, was performed drilling with cutting parameters in Al-7075. All tests were run without coolant at cutting speeds of 4, 12, and 20 m/min and feed rates of 0.1, 0.2, and 0.3 mm/rev and point angle of 90 °, 118°, and 135°. The orthogonal array, signal-to-noise ratio, and analysis of variance (ANOVA) were employed to investigate the optimal drilling parameters of Al-7075. From the analysis of means and ANOVA, the optimal combination levels and the significant drilling parameters on burr height and surface roughness were obtained. The optimization results showed that the combination of low cutting speed, low feed rate, and high point angle is necessary to minimize burr height. The best results of the surface roughness were obtained at lower cutting speed and feed rates while at higher point angle. The predicted values and measured values are quite close to each other; therefore, this result indicates that the developed models can be effectively used to predict the burr height and the surface roughness on drilling of Al-7075. © 2009 Springer-Verlag London Limited.

Degertekin S.O.,Dicle University
Computers and Structures | Year: 2012

Harmony search (HS) algorithm was conceptualized using an analogy with music improvisation process where music players improvise the pitches of their instruments to obtain better harmony. Although the efficiency of HS algorithm has been proved in different engineering optimization applications, it is known that HS algorithm is quite sensitive to the tuning parameters. Several variants of HS algorithm have been developed to decrease the parameter-dependency character of HS algorithm. In this study, two improved harmony search algorithms called efficient harmony search algorithm (EHS) and self adaptive harmony search algorithm (SAHS) are proposed for sizing optimization of truss structures. Four classical truss structure weight minimization problems are presented to demonstrate the robustness of the proposed algorithms. The results of the present algorithms are compared with those of HS algorithm and other meta-heuristic algorithms recently developed in literature. © 2011 Elsevier Ltd. All rights reserved.

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