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Article Citation - WoS: 45Citation - Scopus: 45An Ambipolar Low Band Gap Material Based on Bodipy and Edot(Elsevier Science Bv, 2009) Algi, Fatih; Cihaner, AtillaA novel donor-acceptor type conducting polymer based on BODIPY dye as acceptor and EDOT units as donor parts is synthesized electrochemically. The unique combination of BODIPY and EDOT units provides an ambipolar (n- and p-doping processes) low band gap material (4). This is the first example of p-n junction in an organic pi-conjugated material where BODIPY unit is incorporated directly in the main chain. Furthermore, the polymer film exhibits electrochromic behavior upon p-doping: a color change from light violet (neutral) to indigo (oxidized). (C) 2009 Elsevier B.V. All rights reserved.Article Citation - WoS: 80Citation - Scopus: 85Methylene Blue Photocatalytic Degradation Under Visible Light Irradiation on Copper Phthalocyanine-Sensitized Tio2 Nanopowders(Elsevier Science Bv, 2017) Cabir, Beyza; Yurderi, Mehmet; Caner, Nurdan; Agirtas, Mehmet Salih; Zahmakiran, Mehmet; Kaya, MuratDescribed herein is a new photocatalytic material that shows remarkable catalytic performance in terms of activity and reusability in the photocatalytic degradation of methylene blue (MB) in water. The new catalyst system comprised of copper phthalocyanine modified titanium(IV) oxide (TiO2) nanopowders (CuPc-TiO2\) was prepared by the wet chemical impregnation method to improve the photocatalytic activity of TiO2 and characterized by the combination of various spectroscopic tools including ICP-OES, P-XRD, DR/UV-Vis, FTIR, FE-SEM, SEM-EDX, BFTEM, HRTEM and N-2-adsorption-desorption techniques. The photocatalytic performance of the resulting CuPc-TiO2 in terms of activity and stability was evaluated by the photocatalytic degradation of MB in aqueous solution under mild conditions. Our results revealed that CuPc-TiO2 photocatalyst displayed remarkable activity (TOF = 3.73 mol MB/(mol CuPc + mol TiO2) x h) in the complete (100%) photocatalytic degradation of MB under visible light irradiation (150 W). Moreover, CuPc-TiO2 photocatalyst showed excellent stability against to sintering and clumping throughout the reusability experiments and it retained >80% of its initial activity even at 5th reuse, which makes it reusable photocatalyst in the photocatalytic degradation of MB. (C) 2017 Elsevier B.V. All rights reserved.Article Citation - WoS: 11Citation - Scopus: 13Geometric Distribution of Order k With a Reward(Elsevier Science Bv, 2014) Eryilmaz, SerkanIn this paper, we introduce and study geometric distribution of order k with a reward. In a sequence of binary trials, suppose that each time a success occurs a random reward is received. The distribution of the number of trials until the sum of consecutive rewards is equal to or exceeds the level k is called geometric distribution of order k with a reward. We obtain expressions for the probability mass function of this distribution. (C) 2014 Elsevier B.V. All rights reserved.Article Citation - WoS: 21Citation - Scopus: 24Chaotic Dynamics of Resistively Coupled Dc-Driven Distinct Josephson Junctions and the Effects of Circuit Parameters(Elsevier Science Bv, 2009) Kurt, Erol; Canturk, MehmetTwo distinct Josephson junctions (JJs) connected with a constant coupling resistance R(cp) are theoretically considered to investigate the overall dynamics below and above the critical current I(c). The circuit model of the device is driven by two DC current sources, I(1) and I(2). Each junction is characterized by a nonlinear resistive-capacitive junction (NRCSJ). Having constructed the circuit model, time-dependent simulations are carried out for a variety of control parameter sets. Common techniques such as bifurcation diagrams, two-dimensional attractors and Lyapunov exponents are applied for the determination of chaotic as well as periodic dynamics of the superconducting junction devices. According to the findings, two states (namely superconducting and ordinary conducting) are determined as functions of the source currents. The chaotic current which flows through Rcp exhibits a very rich behavior depending on the source currents I(1) and I(2) and junction capacitances C(1) and C(2). The device characteristics are summarized by a number of three-dimensional phase diagrams in the parameter space. In addition, for certain parameters, hyper-chaotic cases with two positive Lyapunov exponents are encountered. In contrast to earlier studies claiming the need for a sinusoidal feeding current for generating a chaotic signal, our circuitry can easily generate one via a DC source. (C) 2009 Elsevier B.V. All rights reserved.Article Citation - WoS: 3Citation - Scopus: 3q-stieltjes Classes for Some Families of q-densities(Elsevier Science Bv, 2019) Ostrovska, Sofiya; Turan, MehmetThe Stieltjes classes play a significant role in the moment problem allowing to exhibit explicitly infinite families of probability densities with the same sequence of moments. In this paper, the notion of q-moment determinacy/indeterminacy is proposed and some conditions for a distribution to be either q-moment determinate or indeterminate in terms of its q-density have been obtained. Also, a q-analogue of Stieltjes classes is defined for q-distributions and q-Stieltjes classes have been constructed for a family of q-densities of q-moment indeterminate distributions. (C) 2018 Elsevier B.V. All rights reserved.Article Citation - WoS: 38Citation - Scopus: 40Differential Quadrature Solution of Nonlinear Klein-Gordon and Sine-Gordon Equations(Elsevier Science Bv, 2012) Pekmen, B.; Tezer-Sezgin, M.Differential quadrature method (DQM) is proposed to solve the one-dimensional quadratic and cubic Klein-Gordon equations, and two-dimensional sine-Gordon equation. We apply DQM in space direction and also blockwise in time direction. Initial and derivative boundary conditions are also approximated by DQM. DQM provides one to obtain numerical results with very good accuracy using considerably small number of grid points. Numerical solutions are obtained by using Gauss-Chebyshev-Lobatto (GCL) grid points in space intervals, and GCL grid points in each equally divided time blocks. (C) 2012 Elsevier B.V. All rights reserved.Article Citation - WoS: 17Citation - Scopus: 20Prediction of forming limit curve at fracture for sheet metal using new ductile fracture criterion(Elsevier Science Bv, 2018) Dizaji, Shahram Abbasnejad; Darendeliler, Haluk; Kaftanoglu, BilginThe application of ductile fracture criteria (DFCs) in numerical analysis of sheet metal forming processes can lead to the accurate determination of the fracture initiation. In this study, a new uncoupled ductile fracture criterion (DFC) has been developed which considers the effects of material parameters on the forming limit curves (FLCs) and can be easily implemented in the finite element codes. Two different constitutive models have been employed with the new DFC in order to evaluate the results obtained for fracture prediction. Various experimental tests have been utilized to validate the new criterion and its results are also compared with other well-known uncoupled DFCs. It is observed that the new criterion predicts the ductile fracture for all aluminum, steel and stainless steel materials better than the former criteria.Article Citation - WoS: 79Citation - Scopus: 77Doubly Warped Products(Elsevier Science Bv, 2001) Ünal, BIn this paper we study geodesic completeness of Riemannian doubly warped products and Lorentzian doubly warped products. We give necessary conditions for generalized Robertson-Walker spacetimes with doubly warped product spacial parts to be globally hyperbolic. We also state some results about killing and conformal vector fields of doubly warped products.Conference Object Citation - WoS: 2Public Presentation: Who Fears?(Elsevier Science Bv, 2013) Bulca, Meric; Safaei, Ladan AmirHaving a presentation always creates tension among presenters. This study aims at furnishing students with the strategies that both minimize stage fright, and prepare manuscripts with organized content for their speech. As for the strategies, the study suggests ice-breaker mini-presentations throughout the semester in order to encourage the learners to familiarize themselves with speech making before audience. In addition, it leads the participants to follow pre-planned and organized steps prior to the speech. It is observed that following these steps they are more likely to overcome their stage fright as well as to deliver a more organized speech. (C) 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of ALSC 2012Article Citation - WoS: 4Citation - Scopus: 4On Success Runs in a Sequence of Dependent Trials With a Change Point(Elsevier Science Bv, 2018) Eryilmaz, SerkanLet {X-i}(i=1)(n) be a sequence of n dependent binary trials such that the first n(1) in {X-i}(i=1)(n) are of type 1 and follow an exchangeable joint distribution denoted by L-1, and the last n2 elements in {X-i}(i=1)(n) are of type 2 and follow an exchangeable joint distribution denoted by L-2, where n(1) + n(2) = n. That is, the trials within the same group are exchangeable dependent, and the trials in different groups are dependent in a general sense. The exact distributions of the number of success runs of length k in {X-i}(i=1)(n) are obtained under nonoverlapping and at least schemes. (C) 2017 Elsevier B.V. All rights reserved.
