Browsing by Author "Ozbayoglu, Gulhan"
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Article Citation Count: 18Comparison of Different Synthesis Methods to Produce Lithium Triborate and Their Effects on Its Thermoluminescent Property(Springer, 2010) Özbayoğlu, Gülhan; Ozbayoglu, Gulhan; Yilmaz, Aysen; Energy Systems EngineeringLithium triborate (LiB3O5) was produced by different synthesis methods, which included high-temperature solid-state reaction, microwave-assisted high-temperature solid-state reaction, and precipitation-assisted high-temperature solid-state reaction. After the synthesis, metal oxides (CuO and Al2O3) were doped into LiB3O5 to enhance its thermoluminescent (TL) properties, and the TL intensities were compared with each other. The identification and characteristics of undoped and doped LiB3O5 were determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) analyses, differential thermal analyses (DTA), scanning electron microscopy (SEM), and particle size analyzer. The glow curves were obtained by using a TL reader. The results showed that synthesis routes affected the physical and structural properties of lithium triborate, which have an important effect on its TL intensity.Article Citation Count: 4Partitioning of major and trace elements of a Turkish lignite with size and density(oficyna Wydawnicza Politechniki Wroclawskiej, 2011) Özbayoğlu, Gülhan; Energy Systems EngineeringThis research was devoted to determine the concentration and distribution of major and trace elements in a Turkish lignite and to investigate the partitioning behaviour of them in various size and density fractions to estimate the possibility of removal of trace elements by conventional coal cleaning. Three size fractions which were used in industrial coal cleaning processes were chosen. Each size fraction was separated into various density fractions by float and sink tests, which were evaluated for major and trace elements. These tests showed that by applying the same size and density fractions of industrial coal cleaning processes, more than 70% of Mo, Nb, Nd, W, Hg and Zr could be removed, which were approximately equal to the result achieved for ash removal.Article Citation Count: 5Potential of Removing Trace Elements from a Turkish Lignite(Taylor & Francis inc, 2010) Özbayoğlu, Gülhan; Energy Systems EngineeringLignite is a significant source for producing electricity in Turkey. However, the hazardous trace elements content, namely, vanadium (V), chromium (Cr), copper (Cu), arsenic (As), thorium (Th), and uranium (U), are much higher than those observed around the world. In this article, the potential of removing the trace elements from the Lignite obtained from the Soma mine using the gravity separation principles is discussed. The float-sink studies conducted using heavy liquid of 1.3 and 1.9 specific gravities identified that removal of the trace elements from the Soma lignite ranged from 15% to 83%.Article Citation Count: 18Synthesis and thermoluminescence properties of rare earth oxides (Y, Ce-Lu) doped lithium triborate(Elsevier Science Bv, 2011) Özbayoğlu, Gülhan; Ozbayoglu, Gulhan; Yilmaz, Aysen; Energy Systems EngineeringLithium triborate (LiB(3)O(5)) was synthesized by high temperature solid-state reaction method, and then rare earth oxides were doped into LiB(3)O(5) to enhance its thermoluminescent (TL) properties. The identification and characteristics of the obtained compounds were determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) analyses, differential thermal analyses (DTA) and scanning electron microscopy (SEM). The glow curves were obtained using a thermoluminescent (TL) reader. The results revealed that all the rare earth oxides were not good activators for lithium triborate and the obtained compounds could not be used for dosimetric applications.Article Citation Count: 0USE OF BORIC ACID AS A BINDER FOR BRIQUETTING SOME BORON MINE WASTES AND THEIR CALCINED PRODUCTS(Parlar Scientific Publications (p S P), 2010) Özbayoğlu, Gülhan; Ozbayoglu, Gulhan; Ozdemir, Zeynep; Energy Systems EngineeringIn this study, boric acid as a binder for briquetting some boron mine wastes, such as colemanite and ulexite fines and calcined products, which do not meet the market specifications with respect to particle size, were investigated. Effects of water and binder contents, applied pressure, and curing and drying conditions on the briquette quality were evaluated in terms of mechanical strength, water-proofing characteristics and wearing resistance. The best briquettes were obtained at 62.4 MPa pressure (cured at ambient temperature for 24 h and dried at 105 C for 2 h). Only binder free briquettes of uncalcined ulexite gave satisfactory result. The briquette strength increased with an increase in the percentage of binder. The optimum binder content was found to be 5 % by weight for uncalcined ulexite and colemanite as well as calcined colemanite, but 10 To by weight for calcined ulexite. The water-proof briquettes of ulexite and calcined products of ulexite and colemanite fines could be produced. According to wearing resistance, ulexite and colemanite fines as well as calcined product of colemanite showed resistance to abrasion action during transportation and loading.