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Article Citation - WoS: 34Citation - Scopus: 37Hydroxyapatite-Nanosphere Supported Ruthenium(0) Nanoparticle Catalyst for Hydrogen Generation From Ammonia-Borane Solution: Kinetic Studies for Nanoparticle Formation and Hydrogen Evolution(Royal Soc Chemistry, 2014) Durak, Halil; Gulcan, Mehmet; Zahmakiran, Mehmet; Ozkar, Saim; Kaya, MuratThe development of readily prepared effective heterogeneous catalysts for hydrogen generation from ammonia-borane (AB; NH3BH3) solution under mild conditions still remains a challenge in the field of "hydrogen economy". In this study, we report our finding of an in situ generated, highly active ruthenium nanocatalyst for the dehydrogenation of ammonia-borane in water at room temperature. The new catalyst system consists of ruthenium(0) nanoparticles supported on nanohydroxyapatite (RuNPs@nano-HAp), and can be reproducibly prepared under in situ conditions from the ammonia-borane reduction of Ru3+ ions exchanged into nanohydroxyapatite (Ru3+@nano-HAp) during the hydrolytic dehydrogenation of ammonia-borane at 25 +/- 0.1 degrees C. Nanohydroxyapatite-supported ruthenium(0) nanoparticles were characterized by a combination of advanced analytical techniques. The sum of their results shows the formation of well-dispersed ruthenium(0) nanoparticles with a mean diameter of 2.6 +/- 0.6 nm on the surface of the nanospheres of hydroxyapatite by keeping the host matrix intact. The resulting RuNPs@nano-HAp are highly active catalyst in the hydrolytic dehydrogenation of ammonia-borane with an initial TOF value of 205 min(-1) by generating 3.0 equiv. of H-2 per mole of ammonia-borane at 25 +/- 0.1 degrees C. Moreover, they are sufficiently stable to be isolated and bottled as solid materials, which can be reused as active catalyst under the identical conditions of first run. The work reported here also includes the following results: (i) monitoring the formation kinetics of the in situ generated RuNPs@nano-HAp by hydrogen generation from the hydrolytic dehydrogenation of ammonia-borane as the reporter reaction. The sigmoidal kinetics of catalyst formation and concomitant dehydrogenation fits well to the two-step, slow nucleation, followed by autocatalytic surface growth mechanism, P -> Q (rate constant k(1)) and P + Q -> 2Q (rate constant k(2)), in which P is Ru3+@nano-HAp and Q is the growing, catalytically active RuNPs@nano-HAp; (ii) the compilation of kinetic data for the RuNPs@nano-HAp catalyzed hydrolytic dehydrogenation of ammonia-borane depending on the temperature and catalyst concentration to determine the dependency of reaction rate on catalyst concentration and activation parameters (E-a, Delta H-#, and Delta S-#) of the reaction.Article Citation - WoS: 22Citation - Scopus: 22Optical Properties of Tlins2 Layered Single Crystals Near the Absorption Edge(Springer, 2006) Qasrawi, A. F.; Gasanly, N. M.The sample thickness effect on the optical properties of TlInS2 layered crystals has been investigated at room temperature. The absorption coefficient of the samples calculated from the experimental transmittance and reflectance in the photon energy range of 1.10-3.10 eV has two absorption regions. The first is a long-wavelength region of 1.16-1.28 eV. The second region lies above 2.21 eV with a thickness-dependent indirect band gap. The energy gap decreases from 2.333 to 2.255 eV as the sample thickness increases from 27 to 66 mu m. The differential spectra of absorption coefficient demonstrates the existence of a thickness-dependent impurity level being lowered from 2.360 to 2.307 eV as sample thickness increases from 27 to 66 mu m. (c) 2006 Springer Science + Business Media, Inc.Erratum Citation - Scopus: 1Erratum: Robust Stability of Two-Dimensional Uncertain Discrete Systems (ieee Signal Processing Letters (135))(2003) Kar,H.; Singh,V.[No abstract available]Article Citation - WoS: 7Citation - Scopus: 9Pyrrole Coupling Chemistry: Investigation of Electroanalytic, Spectroscopic and Thermal Properties of N-Substituted Poly(bis-Pyrrole) Films(Royal Soc Chemistry, 2013) Mert, Olcay; Demir, Ayhan S.; Cihaner, AtillaAn etheric member of N-linked polybispyrroles (PolybisPy) based on 1-(3-(2-(2-(3-(1H-pyrrol-1-yl)propoxy)ethoxy)ethoxy)propyl)-1H-pyrrole (1) was electrochemically synthesized for the versatile investigation of its exciting electrochromic and ion receptor properties. It has been fully characterized by electroanalytic, spectroscopic, thermal, and four-probe techniques. It was thereby found that P1 shows strong stability, and a reversible redox process as well as a good electrochromic material property; transparent yellow in the neutral state, light pink in the intermediate state, and blue in the oxidized state. Also, the corresponding polymer (P1) exhibited a selective voltammetric response towards Na+ among the alkali series in an organic medium. Moreover, P1 film was employed for the detection of Ag+ ions in the solution with cyclic voltammetry without precipitants or complexing ligands, and SEM images confirmed the deposition of metallic silver on the film surface. These prominent features also make P1 a good candidate for many practical uses, such as the recovery of metals and ion sensors.Article Citation - WoS: 10Citation - Scopus: 10Electroinitiated Polymerization of 2-Allylphenol(Springer-verlag, 2000) Cihaner, A; Önal, AMRedox behaviour of 2-allylphenol (2APhOH) was studied by using cyclic voltammetry (CV) and electroinitiated polymerization was conducted at the measured peak potentials. Constant potential electrolysis (CPE) of the monomer was carried out in acetonitrile-sodium perchlorate, solvent-electrolyte couple, at room temperature. Polymerization of the monomer yielded insoluble polymer films on the surface of the electrode together with the low molecular weight polymers in the bulk of the solution. The structural analysis of the polymers were carried by H-1-NMR and FTIR spectroscopy. Molecular weight of the soluble polymer was determined by GPC. Thermal properties of the polymer film and soluble polymer were studied by DSC. The course of electroinitiated polymerization was monitored by in-situ UV-VIS spectroscopy.Article Citation - WoS: 2Citation - Scopus: 9Dressing the Wound -: Organizing Informal Sector Workers(Monthly Review Foundation, 2005) Selçuk, FÜ[No Abstract Available]Article Citation - WoS: 26Citation - Scopus: 28Utilization of Triso Fuel With Reactor Grade Plutonium in Candu Reactors(Elsevier Science Sa, 2010) Sahin, Suemer; Sahin, Haci Mehmet; Acir, AdemLarge quantities of plutonium have been accumulated in the nuclear waste of civilian LWRs and CANDU reactors. Reactor grade plutonium and heavy water moderator can give a good combination with respect to neutron economy. On the other hand. TRISO type fuel can withstand very high fuel burn-up levels. The paper investigates the prospects of utilization of TRISO fuel made of reactor grade plutonium in CANDU reactors. TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 68%. The fuel compacts conform to the dimensions of CANDU fuel compacts are inserted in rods with zircolay cladding. In the first phase of investigations, five new mixed fuel have been selected for CANDU reactors composed of (1) 4% RG-PuO2+ 96% ThO2; CD 6% RG-PuO2 + 94% ThO2; (3) 10% RG-PuO2+ 90% ThO2; 20% RG-PuO2+ 80% ThO2; (5) 30% RG-PuO2 + 70% ThO2. Initial reactor criticality (k(infinity,0) values) for the modes (1), (2), (3), (4) and are calculated as 1.4294, 1.5035, 1.5678, 1.6249, and 1.6535, respectively. Corresponding operation lifetimes are similar to 0.65, 1.1, 1.9.3.5, and 4.8 years and with burn ups of 30000, 60000, 100000. 200000 and 290000 MW d/tonne, respectively. The higher initial plutonium charge is the higher burn ups can be achieved. In the second phase, a graphical-numerical power flattening procedure has been applied with radially variable mixed fuel composition in the fuel bundle. Mixed fuel fractions leading to quasi-constant power production are found in the 1st, 2nd. 3rd and 4th row to be as 100% PuO2, 80/20% PuO2/ThO2, 60/40% PuO2/ThO2, and 40/60% PuO2/ThO2, respectively. Higher plutonium amount in the flattened case increases reactor operation lifetime to >8 years and the burn up to 580 000 MW d/tonne. Power flattening in the bundle leads to higher power plant factor and quasi-uniform fuel utilization, reduces thermal and material stresses, and avoids local thermal peaks. Extended burn-up grade implies drastic reduction of the nuclear waste material per unit energy output for final waste disposal. (C) 2010 Elsevier BM. All rights reserved.Article Citation - WoS: 21Citation - Scopus: 22Quadruple Fixed Point Theorems Under Nonlinear Contractive Conditions in Partially Ordered Metric Spaces(Hindawi Ltd, 2012) Karapinar, Erdal; Shatanawi, Wasfi; Mustafa, ZeadWe prove a number of quadruple fixed point theorems under phi-contractive conditions for a mapping F : X-4 -> X in ordered metric spaces. Also, we introduce an example to illustrate the effectiveness of our results.Conference Object Aldose Reductase Natural Inhibitors From Ethyl Acetate Extracts From Southern Turkey(Taylor & Francis inc, 2010) Onay, Melih; Coruh, Nursen; Isgor, Belgin[No Abstract Available]Article Citation - WoS: 10Citation - Scopus: 11Fixed Point Theorems Via Auxiliary Functions(Hindawi Publishing Corporation, 2012) Karapinar, Erdal; Salimi, PeymanWe prove new fixed point theorems in the framework of partially ordered metric spaces. The main result is an extension and a generalization of many existing results in the literature. An example is also considered to illustrate the main result.
