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Öğe Active control of a small-scalewind turbine blade containing magnetorheological fluid(MDPI AG, 2018) Bolat F.C.; Sivrioglu S.This research study proposes a new active control structure to suppress vibrations of a small-scale wind turbine blade filled with magnetorheological (MR) fluid and actuated by an electromagnet. The aluminum blade structure is manufactured using the SH3055 (BergeyWindpower Co. Inc., Norman, OK, USA) code numbered airfoil which is designed for use on small wind turbines. A dynamic interaction model between the MR fluid and the electromagnetic actuator is constructed to obtain a force relation. A detailed characterization study is presented for the proposed actuator to understand the nonlinear behavior of the electromagnetic force. A norm based multi-objective H2/H? controller is designed using the model of the elastic blade element. The H2/H? controller is experimentally implemented under the impact and steady state aerodynamic load conditions. The results of experiments show that the MR fluid- electromagnetic actuator is effective for suppressing vibrations of the blade structure. © 2018 by the authors.Öğe Determination of structural, spectrometric and nonlinear optical features of 2-(4-hydroxyphenylazo)benzoic acid by experimental techniques and quantum chemical calculations(2013) Cinar M.; Yildiz N.; Karabacak M.; Kurt M.The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and nonlinear optical properties of 2-(4-hydroxyphenylazo)benzoic acid (HABA) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by using density functional (DFT/B3LYP) method with 6-311++G(d,p) basis set. The vibrational spectra of title compound were recorded in solid state with FT-IR and FT-Raman spectrometry in the range of 4000-400 cm -1 and 4000-10 cm -1 ; respectively. The fundamental assignments were done on the basis of the recorded spectra and total energy distribution (TED) of the vibrational modes. The 1 H and 13 C NMR spectra were recorded in deuterated DMSO solution, and gauge-invariant atomic orbitals (GIAOs) method was used to predict the isotropic chemical shifts. The UV-Vis absorption spectra of the compound were observed in the range of 200-800 nm in ethanol, methanol and water solvents. To investigate the nonlinear optical properties, the polarizability, anisotropy of polarizability and molecular first hyperpolarizability were computed. A detailed description of spectroscopic behaviors of compound was given based on the comparison of experimental measurements and theoretical computations. © 2012 Elsevier B.V. All rights reserved.Öğe Asymmetric Friedel-Crafts alkylation of pyrrole with nitroalkenes catalyzed by a copper complex of a bisphenol A-derived Schiff base(Elsevier Ltd, 2015) Özdemir H.S.; Şahin E.; Çakici M.; Kiliç H.The asymmetric Friedel-Crafts (FC) alkylation of pyrrole with nitroalkenes was mediated by CuBr2 and a novel bisphenol A-derived chiral catalyst at room temperature. The catalyst was found to be applicable for the asymmetric FC alkylation of pyrrole with a wide range of nitroalkenes, affording optically active alkylated pyrroles with enantioselectivities up to 94%. Furthermore, enantiomerically pure 3-nitro-2-arylpropanamides were prepared by the oxidative cleavage of the pyrrole rings in the FC products with NaIO4/RuCl3 to demonstrate the synthetic application of the products. © 2015 Elsevier Ltd. All rights reserved.Öğe In vitro inhibitory effects of palonosetron hydrochloride, bevacizumab and cyclophosphamide on purified paraoxonase-I (hPON1) from human serum(Elsevier B.V., 2016) Türkeş C.; Söyüt H.; Beydemir S.In this study, we investigated the effects of the drugs, palonosetron hydrochloride, bevacizumab and cyclophosphamide, on human serum paraoxonase-I (hPON1) enzyme activity in in vitro conditions. The enzyme was purified ~231-fold with 34.2% yield by using ammonium sulphate precipitation, DEAE-Sephadex A-50 ion-exchange chromatography and Sephadex G-200 gel-filtration chromatography from human serum. hPON1 exhibited a single protein band on the SDS polyacrylamide gel electrophoresis. The inhibition studies were performed on paraoxonase activity of palonosetron hydrochloride, bevacizumab and cyclophosphamide. Ki constants were found as 0.033 ± 0.001, 0.054 ± 0.003 mM and 3.419 ± 0.518 mM, respectively. Compared to the inhibition rates of the drugs, palonosetron hydrochloride has the maximum inhibition rate. However, inhibition mechanisms of the drugs were determined as noncompetitive by Lineweaver-Burk curves. © 2016 Elsevier B.V.Öğe New water mites of the family Hygrobatidae (Acari, Hydrachnidia) from Turkey(2013) Esen Y.; Peši? V.; Erman O.; Kaya Y.In this study, the findings of three water mite species of the family Hygrobatidae collected from different streams in Turkey were evaluated. Hygrobates (s. str.) anatolicus Esen & Peši?, sp. n. is described as new for science. Hygrobates (Rivobates) diversiporus Sokolow, 1927 and Atractides (s. str.) nikooae Peši?, 2004, which were illustrated and thoroughly discussed, are new records for the Turkish fauna. © Yunus Esen et al.Öğe Selective Separation, Preconcentration, and Determination of Au (III) Ions in Environmental Samples by Coprecipitation With a 1,2,4-Triazole Derivative(2013) Ozdes D.; Duran C.; Serencam H.; Şahin D.An effective, simple, lowcost, and accurate separation and preconcentration procedure which has minimal impact on the environment has been developed. It is based on the carrier element-free coprecipitation (CEFC) of Au(III)ions using N-benzyl-2-{[3-methyl-4-(2morpholine-4-ylethyl)-5-oxo-4,5-dihydro-1H-1,2, 4-triazole-1-yl] acetyl)hydrazinecarboxamide (BODAH) as an organic coprecipitant. Determination of the Au(IH) ion levels was performed by flame atomic absorption spectrometry (FAAS). The developed method provided a detection limit of 0.36 ?g L-1 and the relative standard deviation for Au(III)ions was found to be 5.1%. Spike tests and certified reference material analyses were performed to validate the method. The developed method was systematically investigated in different sets of experimental parameters that influence the quantitative recovery of the Au(III)ions. Based on these investigations, the optimum conditions for the determination of Au(III) ions at trace levels were established. The coprecipitation method was applied to anodic slime, gold ore, soil, and water samples to determine their Au(III)levels.Öğe Surface and optical properties of indium tin oxide layer deposition by RF magnetron sputtering in argon atmosphere(Springer Verlag, 2016) Yudar H.H.; Korkmaz Ş.; Özen S.; Şenay V.; Pat S.This study focused on the characterization and properties of transparent and conductive indium tin oxide (ITO) thin films deposited in argon atmosphere. ITO thin films were coated onto glass substrates by radio frequency (RF) magnetron sputtering technique at 75 and 100 W RF powers. Structural characteristics of producing films were investigated through X-ray diffraction analysis. UV–Vis spectrophotometer and interferometer were used to determine transmittance, absorbance and reflectance values of samples. The surface morphology of the films was characterized by atomic force microscope. The calculated band gaps were 3.8 and 4.1 eV for the films at 75 and 100 W, respectively. The effect of RF power on crystallinity of prepared films was explored using mentioned analysis methods. The high RF power caused higher poly crystallinity in the produced samples. The thickness and refractive index values for all samples increased respect to an increment of RF power and were calculated as 20, 50 nm and 1.71, 1.86 for samples at 75 and 100 W, respectively. Finally, the estimated grain sizes for all prepared films decreased with increasing of 2? degrees, and the number of crystallite per unit volume was calculated. It was found that nearly all properties including sheet resistance and resistivity depend on the RF power. © 2016, Springer-Verlag Berlin Heidelberg.Öğe Highly Enantioselective Production of Chiral Secondary Alcohols with Candida zeylanoides as a New Whole Cell Biocatalyst(Wiley-VCH Verlag, 2017) Şahin E.; Dertli E.The increasing demand for biocatalysts in synthesizing enantiomerically pure chiral alcohols results from the outstanding characteristics of biocatalysts in reaction, economic, and ecological issues. Herein, fifteen yeast strains belonging to three food originated yeast species Candida zeylanoides, Pichia fermentans, and Saccharomyces uvarum were tested for their capability for asymmetric reduction of acetophenone to 1-phenylethanol as biocatalysts. Of these strains, C. zeylanoides P1 showed an effective asymmetric reduction ability. Under optimized conditions, substituted acetophenones were converted to corresponding optically active secondary alcohols in up to 99% enantiomeric excess and at high yields. The preparative scale asymmetric bioreduction of 4-nitroacetophenone (1m) by C. zeylanoides P1 gave (S)-1-(4-nitrophenyl)ethanol (2m) with 89% yield and > 99% enantiomeric excess. Compound 2m has been obtained in an enantiomerically pure and inexpensive form. Additionally, these results indicate that C. zeylanoides P1 is a promising biocatalyst for the synthesis of chiral alcohols in industry. © 2017 Wiley-VHCA AG, Zurich, SwitzerlandÖğe Investigation of the effect of RF energy on optical, morphological, chemical and antibacterial properties of PolyTerpenol thin films obtained by RF-PECVD technique(Springer New York LLC, 2018) Bayram O.; Simsek O.In this study, it was aimed to obtain PolyTerpenol thin films by radio frequency plasma enhanced chemical vapor deposition technique using Terpinen-4-ol essential oil, which is organic compounds. The surface morphology and chemical properties of polymer thin films were investigated by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy. AFM analyzes of PolyTerpenol thin films revealed that the thin films are homogeneous, smooth and nonporous. The optical properties of the thin films were determined using UV–Vis spectrophotometer. When optical band gaps of thin films were examined, it was found that this value varied from 3.83 to 3.20 eV. The extinction coefficients of the obtained thin films according to the increasing RF energy were calculated as 0.0011, 0.0060, 0.0085 and 0.0150, respectively, at a wavelength of 320 nm. In addition, antibacterial effects of these thin films against Escherichia Coli (E.Coli) bacteria were also investigated. The PolyTerpenol thin films were found to have high antibacterial activity against E. Coli bacteria. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.Öğe An experimental and theoretical investigation of Acenaphthene-5-boronic acid: Conformational study, NBO and NLO analysis, molecular structure and FT-IR, FT-Raman, NMR and UV spectra(Elsevier B.V., 2013) Karabacak M.; Sinha L.; Prasad O.; Asiri A.M.; Cinar M.The solid state Fourier transform infrared (FT-IR) and FT-Raman spectra of Acenaphthene-5-boronic acid (AN-5-BA), have been recorded in the range 4000-400 cm1 and 4000-10 cm 1, respectively. Density functional theory (DFT), with the B3LYP functional was used for the optimization of the ground state geometry and simulation of the infrared and Raman spectra of the molecule. The vibrational wave numbers and their assignments were examined theoretically using the Gaussian 09 set of quantum chemistry codes and the normal modes were assigned by a scaled quantum mechanical (SQM) force field approach. Hydrogen-bonded dimer of AN-5-BA, optimized by counterpoise correction, has also been studied by B3LYP at the 6-311++G(d,p) level and the effects of molecular association through O-H·O hydrogen bonding have been discussed. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by Gauge-Including Atomic Orbital (GIAO) method. Natural bond orbital (NBO) analysis has been applied to study stability of the molecule arising from charge delocalization. UV spectrum of the title compound was also recorded and the electronic properties, such as frontier orbitals, and band gap energies were measured by TD-DFT approach. The first order hyperpolarizability (?), its components and associated properties such as average polarizability and anisotropy of the polarizability (? and ??) of AN-5-BA was calculated using the finite-field approach. © 2013 Elsevier B.V. All rights reserved.Öğe Electrorheological Fluids Equations Involving Variable Exponent with Dependence on the Gradient via Mountain Pass Techniques(Taylor and Francis Inc., 2016) Mashiyev R.A.; Ekincioglu I.This article deals with a quasilinear elliptic equation with variable exponent under a homogenous Dirichlet boundary-value condition, where nonlinearity also depends on the gradient of the solution. By using an iterative method based on Mountain Pass techniques, the existence of a positive solution is obtained. © 2016, Copyright © Taylor & Francis Group, LLC.Öğe The impact of internal aerogel retrofitting on the thermal bridges of residential buildings: An experimental and statistical research(Elsevier Ltd, 2016) Cuce E.; Cuce P.M.In this research, internal thermal superinsulation in residential buildings is experimentally and statistically evaluated in terms of potential thermal bridging effects. As a consequence of significant deviations in thermal resistance values in buildings at post-retrofit, large amounts of heat losses occur through non-insulated building elements such as separating walls. Therefore, it is of vital importance to determine the level of energy loss due to such thermal bridges through an internal thermal superinsulation retrofit conducted in a typical UK building. 20 mm thick fibre-silica opaque aerogel blanket is implemented internally on the walls of a test bedroom, and the heat flux from the separating wall is measured and compared for the cases of pre and post-retrofit. The results reveal that the average amount of heat loss through the non-insulated separating wall at the post-retrofit is 5.86 W/m2, whereas it is only 0.66 W/m2 at the pre-retrofit. The results are also verified through a statistical model, which is presented for the first time in literature. The novel model is capable of providing information about potential energy loss from non-insulated walls as a function of location. © 2016 Elsevier B.V. All rights reserved.Öğe Enhanced Pinning Properties of Laser-Irradiated Bulk MgB2 Superconductors(Springer New York LLC, 2017) Erdem O.; Yanmaz E.In order to investigate the effect of laser irradiation on the superconducting properties of MgB2, a pellet-shaped sample was produced and cut into two pieces. The dot-shaped molten patterns, with the distance of 100 µm between them, were formed on the surface of one of the pieces by using an Nd:YVO4 laser. The grains of the irradiated sample were significantly grown due to the laser-induced sintering. The modified surface appeared to have dense and compacted grains as a result of increasing interconnectivity among the superconducting grains. The critical current densities at 5 K in a field of 3 T were found to be 5.38 × 104 and 8.96 × 104 A cm?2 for the reference and the irradiated samples, respectively. The increment of critical current density for the irradiated sample is presumably connected with the changing of pinning mechanism after the laser irradiation. For the irradiated sample which showed a higher value of critical current density at 5 K under high fields, ?? pinning was obtained as a dominant pinning mechanism, while the normal point pinning was dominant for the reference one. These results point out that the superconducting properties of bulk MgB2 can be changed and improved via laser irradiation in a short time. © 2016, Springer Science+Business Media New York.Öğe Some physicochemical properties of wild and cultivated pomegranates (Punica granatum L.)(Scibulcom Ltd., 2017) Gozlekci S.; Ercisli S.; Choudhary R.; Cakir O.; Sagbas H.I.The fruits of seven wild grown pomegranate genotypes and well-known cultivar Hicaznar were analysed for several physical (fruit mass, shape index, calyx length, peel yield, peel thickness, aril yield and juice yield) and chemical (soluble solid content, titratable acidity, pH, soluble solid content/acidity, total phenolic content, antioxidant activity and total anthocyanin) properties. There were statistical differences within wild genotypes and also between wild genotypes and cv. Hicaznar in terms of most of the parameters. The average fruit mass ranged from 127-192 g among wild genotypes and cv. Hicaznar had 394 g fruit mass. The wild genotypes, in general, had lower aril and juice yields than cv. Hicaznar. However they have higher total phenolic content and antioxidant activity than cv. Hicaznar.Öğe Direct and fast growth of GaAs thin films on glass and polyethylene terephthalate substrates using a thermionic vacuum arc(Springer New York LLC, 2015) Pat S.; Korkmaz Ş.; Özen S.; Şenay V.Using a thermionic vacuum arc, single?crystal gallium arsenide (GaAs) layers of micron thickness were grown on PET and glass substrates in 2 min. We present a new deposition mechanism and parameters for GaAs thin films produced in a very short time. Crystal direction was found to be (111) plane for the GaAs/PET sample and (022) plane and (133) plane for the GaAs/glass sample, respectively. The average roughness values of the deposited thin films were determined to be approximately 30 nm for GaAs/PET and 60 nm for GaAs/glass. The structures can be seen clearly in field emission scanning electron microscopy and atomic force microscopy. The obtained optical band is nearly the same with literatures values of the GaAs. Although produced structures in different crystal formations, only aggregations dimensions and absorbance of the layers were changed. Obtained refractive index values are nearly same with database info. © 2015, Springer Science+Business Media New York.Öğe Solar Pond Window Technology for Energy-Efficient Retrofitting of Buildings: An Experimental and Numerical Investigation(Springer Verlag, 2017) Cuce E.; Cuce P.M.Windows are responsible for an important proportion of heat loss from building envelope due to inadequate insulative characteristics of traditional glazing products. In this respect, advanced glazing solutions are of vital importance to mitigate energy demand of buildings, thus to reduce carbon emissions. Therefore, in this research, a novel glazing technology called solar pond window is introduced, and it is numerically and experimentally investigated for different design configurations. The optimum design of this novel glazing covers four 5-mm-thick glass panes, two 20-mm-thick water layers, and one 20-mm-thick Krypton layer in the middle. The average heat transfer coefficient (U-value) of the optimum case is found to be about 0.40 W/m 2 K. If air is used as insulative gas in the interlayer, the U-value of the glazing is determined to be around 0.90 W/m 2 K, which is still competitive with the U-value range of argon-filled triple-glazed windows with low-e coatings. The fabrication cost of the optimum design of solar pond window is around €120/m 2. Overall, solar pond window technology is a cost-effective and energy-efficient glazing, which has a great potential to be the future of fenestration products as well as being capable of meeting the latest building fabric standards. © 2016, King Fahd University of Petroleum & Minerals.Öğe Analysis of structures by total potential optimization using meta-heuristic algorithms (TPO/MA)(Nova Science Publishers, Inc., 2013) Toklu Y.C.; Toklu N.E.Use of meta-heuristic algorithms in analysis of structures is much more recent thantheir use in design of structures. Effectively, while design optimization makes use ofgenetic algorithms, simulated annealing, swarm optimization, etc. since about half acentury with an increasing interest, these techniques are being used in structural analysissince a decade only.Total Potential Optimization using Meta-heuristic Algorithms (TPO/MA), thoughbeing an emerging method at the moment, has proved to be very efficient in solvingnonlinear problems, involving both material and geometric nonlinearities. Thecapabilities of the method in treating under-constrained problems and problems with nonuniquesolutions are much more advanced than the classical methods including the wellknownFinite Element Method. © 2013 Nova Science Publishers, Inc. All rights reserved.Öğe Development of teacher academic optimism scale: The validity and reliability study(Pegem Akademi Yayincilik Egitim Danismanlik Hizmetleri, 2018) Ergen Y.; Elma C.The study aims to develop a valid and reliable academic optimism scale that can be used to determine teachers' academic optimism levels. The study was conducted through a total number of 404 primary school teachers who worked in the central districts of Malatya Province during 2014-2015 academic year. The content validity and face validity of the scale were determined via expert recommendations. An explanatory factor analysis and a confirmatory factor analysis were conducted to determine the construct validity of the scale. After the expert opinions, 80 items reduced to 64 and the data was collected by the use of these 64 items. An exploratory factor analysis revealed 5 factors reducing 64 items in to 33 and explaining 58.56% of the total variation in the data. The five-factor model obtained through an explanatory factor analysis after removal of one item as a result of the confirmatory factor analysis was observed to be highly consistent. Different from previous related research, the result showed that a new dimension as "Maneger Trust" emerged as a part of "Teacher Academic Optimism Scale". And finally this scale could be used as a valid and reliable instrument in the future studies.Öğe Examination of absorption effects at the Compton to coherent scattering intensities X-rays using Fe-Ca and Fe-Ti binary compounds with WDXRF(American Institute of Physics Inc., 2017) Boydaş E.; Boydaş M.G.; Allm B.Matrix absorption effects have been examined with scattered X-rays by using WDXRF system for Fe-Ca and Fe-Ti binary compounds. Fe as analyte and elements which some of them the K absorption edge just below the characteristic K X-ray energies of the analyte (Fe) as matrix have been chosen. Pure and binary with Fe ratio ranging from 10% to 90% samples were prepared with these elements. These samples have been analyzed in WDXRF system. At the end of measurement, the coherent and Compton scattering X-rays data of Rh K? X-rays from these samples have been obtained. Matrix absorption effects have been examined by calculating coherent / Compton scattered X-rays intensity ratio. © 2017 Author(s).Öğe A Novel approach for modeling mechanical behavior of porous media(2011) Altan B.S.; Mollamahmutoglu M.A multi-scale novel homogenization technique is introduced to model mechanical behavior of open-cell porous media. The proposed method consists of primarily four components. The first component is based on two assumptions. First, a random porous structure can be approximated by superimposing regular grids that are interacting with each other at "junction" points. The second component consists of replacing each grid by an equivalent continuum. The forces at the junction points are also replaced by interacting body forces. The third component is to represent the equivalent media by single medium by expressing the "average stresses" in the elastic mixture in terms of the "average displacement" It is discussed how to extract the information about the geometrical and mechanical properties of the grids by comparing the analytical and experimental data for the dispersion of waves propagating in porous medium.
