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Öğe ASSESSMENT OF PILLAR DIMENSIONS OF CANKIRI-TURKEY ROCK SALT MINE BY NUMERICAL ANALYSES(INT SCIENTIFIC CONFERENCE SGEM, 2011) Ozsen, Hakan; Ozkan, Ihsan; Sensogut, CemCankiri rock salt formation is one of the most important rock salt sources of Turkey. Rock salt production in this area is performed by underground room and pillar mining method approximately 150 m under existing topography. However, pillar dimensions which are used in Cankiri rock salt mine are determined by trial and error method. Aim of this study is to create a model which will overlap long and short term rock mechanics analysis results with in-situ stresses and in-situ deformations. By the evaluation of these results pillar dimensions were determined by numerical methods. Numerical analyses were carried out with PHASE(2) software which uses a hybrid numerical modeling method. Firstly the pillar dimensions applied at the present time were investigated then different pillar dimensions were tested in order to investigate the boundary conditions of safe pillar dimensions.Öğe DETERMINATION OF COMBUSTION DEGREE OF SOME COAL SAMPLES FROM THE SHORT AND SULPHUR ANALSIS RESULTS BY USING ARTIFICIAL NEURAL NETWORKS(INT SCIENTIFIC CONFERENCE SGEM, 2011) Ozsen, Seral; Ozsen, Hakan; Sensogut, CemCoal is the most consumed fossil fuel in the world. Determination of the thermal properties of coal is a very important matter and it is not straightforward because of the heterogeneous structure of the coal. The short and elementary analysis results of coals with different carbonization degrees are different. The mineral composition of a coal also affects the thermal behavior. To detect thermal properties of coals, thermal analysis devices are generally used in many widespread methods. The most widely used methods in thermal analysis of coals are Differential Thermal Analysis (DTA) and Thermogravimetry (TG). In this study however, a different analysis method to determine combustion degree of coals was applied. By utilizing from some properties of coals obtained by short analysis and sulphur analysis, an Artificial Neural Network (ANN) was trained to predict the combustion degrees of coals. For this application 84 coal samples were prepared from 28 different locations in TURKEY. Among these, 67 samples were used in training ANN and the remaining 17 were used in test procedure. For the test samples, the trained ANN was used to predict the combustion degrees of them by presenting 8 different properties obtained from short and Sulphur analysis results. Then the mean squared error (mse) was calculated between the real combustion degrees which were also determined from the TG method and predicted combustion degrees of ANN. The test mse was found to be 2.9x10(-4). This result means that the trained ANN could predict combustion degree of a coal sample with a mean error of 2.9x10(-4). When the time and effort spend on determining thermal property of a coal sample with a classical method is considered, this gives another alternative to the experimenter for determining combustion degree of that sample in more short and effortless manner.Öğe Effect of salt crystallization on stones of historical buildings and monuments, Konya, Central Turkey(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Zedef, Veysel; Kocak, Kerim; Doyen, Adnan; Ozsen, Hakan; Kekec, BlIgehanIn this study, we investigated the chemical and physical properties of the volcanic rocks used as building stones in historical places and monuments. The chemical weathering effect of salt crystallization on these stones was measured on the laboratory conditions (in most cases, used samples were very small). For this purpose, the dry weight loss (DWL) test was conducted. The rocks of dacite, andesite and tuffs of volcanic origin have different durability against salt crystallization. The most stable rocks are dacites (DWL 2.06%) which were used in the construction of Hittite monuments at Eflatun. The durability of the stones is closely related to their chemical, mineralogical, petrographical and mechanical properties. The stones used in the historical buildings are generally much more stable than present-day building stones. (c) 2005 Elsevier Ltd. All rights reserved.Öğe Effect of salt crystallization on weathering of pyroclastic rocks from Cappadocia, Turkey(SPRINGER HEIDELBERG, 2017) Ozsen, Hakan; Bozdag, Ali; Ince, IsmailSalt crystallization is the most significant factor in the degradation of the natural stones used in cultural and historical structures. Stones decay partially or fully as a result of this exposure. This study is the investigation of the degradation of historical monuments (underground cities and semiunderground settlements) carved in pyroclastic rocks in Cappadocian Region which takes part in World Cultural Heritage List. Samples of pyroclastic rocks were collected from six different quarries in Cappadocia, Turkey. To understand the contribution of salt crystallization to this weathering, dry weight loss (DWL) tests were performed on these samples. To investigate the correlations between salt crystallization and other rock properties, porosity, water absorption, ultrasonic velocity, uniaxial compressive strength, Brazilian tensile strength, and point load index were also measured. During the SC process of weathering, the results showed that porosity and water absorption increased for all the samples whereas ultrasonic velocity, uniaxial compressive strength, tensile strength, and point load index values decreased. Evaluation of the data obtained from these tests showed very high logarithmic correlations between the dry weight loss values and the mechanical properties.Öğe Measurement and mathematical modelling of the creep behaviour of Tuzkoy rock salt(PERGAMON-ELSEVIER SCIENCE LTD, 2014) Ozsen, Hakan; Ozkan, Ihsan; Sensogut, Cem[Abstract not Available]
