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Article Citation - WoS: 7Citation - Scopus: 6Temperature-Dependent Structural Transition, Electronic Properties and Impedance Spectroscopy Analysis of Tl2ingas4< Crystals Grown by the Bridgman Method(Elsevier Sci Ltd, 2018) Qasrawi, A. F.; Alkarem, Qotaibah A.; Gasanly, N. M.In this work, we report the temporary structural modifications associated with the in situ heating of the Tl2InGaS4 crystals in the temperature range of 300-420 K. The analysis of the X-ray diffraction patterns revealed the temperature-independent possible phase transformations between the monoclinic and triclinic phases. The temperature analysis of the lattice parameters, crystallite size, strain, dislocation density and stacking faults has shown a temporary enhancement in the crystallinity of this compound above 375 K. Significant increase in the grain size accompanied to decrease in the strain, defect density and stacking faults was observed above this temperature. The scanning electron microscopy imaging has shown that the crystals are layer structured with high quality layers of thicknesses of similar to 12 nm. In addition the energy dispersive X-ray analysis has shown that the crystal comprise no detectable impurity. Moreover, the room temperature optical characterizations has shown that the Tl2InGaS4 exhibit an energy band gap of 2.5 eV. The temperature dependent electrical resistivity measurements indicated highly resistive crystal with activation energy values of 0.84 and 0.19 eV above and below 375 K, respectively. On the other hand, room temperature impedance spectroscopy analysis in the frequency domain of 10-1800 MHz has shown that the crystal exhibits negative resistance and negative capacitance effects below and above 1580 MHz. The crystals are observed also to behave as band stop filter with notch frequency of 1711 MHz.Article Citation - WoS: 9Citation - Scopus: 10Determination of the Relationship Between Uniaxial and Triaxial Swelling Equations for Clay Bearing Rocks(Springer Heidelberg, 2013) Bilir, M. Erdinc; Sari, Y. Dursun; Ozarslan, Ahmet; Genis, Melih; Sel, IbrahimDesign in swelling mediums is mostly based on uniaxial data since the standards proposed by the International Society for Rock Mechanics Commission on Swelling Rocks for uniaxial tests are in the form of recommendations, triaxial sets are not highly available; and there is no standard developed for triaxial tests. The main purpose of this study is to define the relationship between the uniaxial and the triaxial swelling equations and to predict the triaxial values using the uniaxial data. The other purpose of the study is to contribute to the development of the standards and to expand the data available in the literature about triaxial swelling behavior. Numerous uniaxial and triaxial swelling tests were performed on the samples from seven different locations, in Turkey, in a state of the art swelling laboratory. As a result of the determination of the triaxial swelling behavior of these samples, the relationships between the uniaxial and the triaxial swelling data for the individual samples as well as the whole set of samples are expressed by the equations derived from the statistical analyses.
