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Öğe An exergy analysis of a concentric tube heat exchanger using hBN-water nanofluids(Inder Science Publishers, 2021) Budak Ziyadanoğulları, Neşe; Perçin, SüleymanThis study investigated the effects of using nanofluids prepared with hexagonal boron nitride (hBN) nanoparticles on the thermal performance and pressure drop of a concentric tube heat exchanger. Experiments were carried out with water-hBN nanofluids for stable, dispersed, 0.01%, 0.1% and 1% volume concentrations, at different flow rates and Reynolds numbers under parallel and counter-flow conditions. When the experimental results were examined, the exergy loss was higher in the parallel-flow heat exchanger compared to the counter-flow heat exchanger. The highest exergy loss value was obtained for distilled water at the highest Reynolds number (Re = 8,700) for parallel flow operation at 170 W. The exergy loss of water at the highest Reynolds number (Re = 8,700) for parallel flow operation increased by 15.7%, 24.8% and 49.8% for hBN-water concentrations of 0.01%, 0.1% and 1%, respectively. Exergy loss of water at the highest Reynold number (Re = 8,700) for counter flow operation increased by 11.3%, 17.3% and 29.2% for hBN-water concentrations of 0.01%, 0.1% and 1%, respectively. When evaluating the exergy analysis of the system, exergy losses due to pressure drops were negligible for both flows (parallel and counter).Öğe New voltammetric strategy for determination and electrochemical behaviors of metformin by pencil graphite electrode in the NaOH(Indian Chemical Society, 2020) Altunkaynak, Yalçın; Yavuz, Ömer; Levent, AbdulkadirMetformin(MET), an oral antidiabetic drug commonly used in the treatment of diabetes, is a drug that increases insulin sensitivity in the biguanide group [1]. MET shows its pharmacological effect by lowering the glucose level in the blood. In the literature research, there are studies using electrochemical techniques for the analysis of MET in biological fluid and drug forms[1-6]. In this study, the electrochemical properties of MET, one of the drugs used in the treatment of diabetes, were performed using a pencil graphite electrode in NaOH (0.1 M) solution. This compound was recorded with an irreversible and diffusion controlled adsorption oxidation peak at approximately +1.28 V by cyclic voltammetry. With square wave stripping voltammetry, it was observed that the peak current signals of MET in the concentration range of 2.76-24.8 µM in 0.1M NaOH solution increased linearly. At a concentration of 2.76 µM (n = 9), the limit of detection and relative standard deviation were calculated as 9.03 nM (1.495 ngmL-1 ) and 3.25 %, respectively. This method has been successfully applied for MET analysis in pharmaceutical preparations and urine samples without any separation.Öğe A generalization of the Katzman-Zhang algorithm(Elsevier, 2021-03) Yeşil, MehmetIn this paper, we study the notion of special ideals. We generalize the results on those as well as the algorithm obtained for finite dimensional power series rings by Mordechai Katzman and Wenliang Zhang to finite dimensional polynomial rings.Öğe Measuring the sediment thickness in urban areas using H/V spectral ratio method in Batman region, Southeast Turkey(SpringerLink, 2021-02-03) Dinç, Salih; Alpaslan, Nuray; Yılmaz, SalimIn this study, microtremor records measured with a 3-component seismometer in Batman city center, which was established on the plain, were evaluated for the geological structure of the region and soil forming units. The measurements obtained from the field survey were evaluated with the Geopsy program by using the horizontal/vertical spectral ratio (Nakamura 1989) and the geological condition of the area and soil dominant frequency were determined. Soil characteristics of Batman City, which is geologically located on a plain, was evaluated by finding the loose units in the site with the map consisting of shear wave velocities (VS) found by applying the T = Σ4Hi /Vsi formula of Kanai (1983), which was developed for the soft soil layer on the bedrock, to the dominant frequency values (F0) obtained from the microtremor measured and soil classes corresponding to these values; and depth (H) and shear wave velocities (VS) were found by applying Formula (6) and the soil classes corresponding to these values. The dominant frequency at the measurement points and the lithology of the soil forming units were evaluated together to create dominant frequency maps of the region, and the relationship between the geology of the region and obtained microtremor measurements was discussed.Öğe New voltammetric strategy for determination and electrochemical behaviors of oxaliplatin by CPT-BDD electrode(Indian Chemical Society, 2020) Aslan, Mehmet; Levent, AbdulkadirVarious drugs made of metal compounds have been used in many diseases including cancer[1]. Studies on Oxaliplatin in the literature are these [2-6]. Oxaliplatin (OxPt), which is a platinum analogue with anti-cancer effect, was accentuated. OxPt is separated from cisplatin, one of analogues of platinum, by replacing 1,2-diaminocyclohexane with amine groups. In this study, a simple, fast and sensitive voltammetric method was developed for OxPt which shows anticancer effects with cytotoxic properties. The boron-doped diamond (BDD) electrode was activated electrochemically in cathodic direction in 0.5 M H2SO4 medium. Electrochemical properties of OxPt were investigated on BDD electrode surface using square-wave and cyclic voltammetry techniques. OxPt in Britton-Robinson(BR) buffer (pH 5.0) gave a well-determined voltammetric response at +1.01 V (vs. Ag/AgCl) using the square-wave voltammetry technique. The developed voltammetric technique was found to be linear with the concentration range of 1.0-3.5 μM in the BR (pH 5.0) medium and the limit of detection was 0.276 μM (0.109 μg mL-1 ). Recommended method was successfully applied to drug forms of OxPt.Öğe Geochemistry of the cretaceous-tertiary (K/T) transition clays in the Southeastern Turkey(Komitet Zrównoważonej Gospodarki Surowcami Mineralnymi PAN, 2024-04-17) Tetiker, SemaThe mineralogy and chemistry of Upper Cretaceous -Lower Paleocene claystone sediments from Mardin and Batman, southeastern Turkey, were analyzed. The main mineral paragenesis in the Upper Cretaceous member formed chlorite-smectite (C -S) and illite, while the Lower Paleocene member occurred of chlorite -vermiculite (C -V) and vermiculite minerals. The clays were silica -poor but indicated high values of Al, Fe, Mg, Cr, Ni, V, and Zr. Lower contents of the alkali elements (Na, Ca, Mg, K) of the clayey sediments suggests a relatively denser weathering of the source area. The mineralogical compositions, major element ratios, trace, and rare earth element (REE) contents of the sediments show that the Upper Cretaceous member consists of materials with a mainly felsic source lithology, while relatively contributions from basic sources are found in the Lower Paleocene unit. A comparison of the major and trace element contents of the phyllosilicate/clay minerals with the members revealed that the patterns of the clays were different from each other, although the enrichments/decreases varied depending on the origin (basement rocks or detrital) of the derived rocks, minerals, and elements. REE content of clays increased from detrital to phyllosilicate/clay minerals of chemical/diagenetic/neoformation origin during the Lower Paleocene. During the Cretaceous and Tertiary periods, local or regional geodynamic and diagenetic events largely governed the rock sedimentation processes and provenance variations amongst Germav Formation members.
