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Article Citation - WoS: 45Citation - Scopus: 48Refractive Index, Band Gap and Oscillator Parameters of Amorphous Gase Thin Films(Wiley-v C H verlag Gmbh, 2005) Qasrawi, AF; Department of Electrical & Electronics EngineeringGaSe thin films are obtained by evaporating GaSe crystals onto ultrasonically cleaned glass substrates kept at room temperature under a pressure of similar to 10(-5) Torr. The X-ray analysis revealed that these films are of amorphous nature. The reflectance and transmittance of the films are measured in the incident photon energy range of 1.1-3.0 eV. The absorption coefficient spectral analysis revealed the existence of long and wide band tails of the localized states in the low absorption region. The band tails width is calculated to be 0.42 eV. The analysis of the absorption coefficient in the high absorption region revealed an indirect forbidden band gap of 1.93 eV. The transmittance analysis in the incidence photon wavelength range of 500-1100 nm allowed the determination of refractive index as function of wave length. The refractive index-wavelength variation leads to the determination of dispersion and oscillator energies as 31.23 and 3.90 eV, respectively. The static refractive index and static dielectric constant were also calculated as a result of the later data and found to be 9.0 and 3.0, respectively.Article Citation - WoS: 9Citation - Scopus: 10The Synthesis, Characterization and Energy Transfer Efficiency of a Dithienylpyrrole and Bodipy Based Donor-Acceptor System(Tubitak Scientific & Technological Research Council Turkey, 2009) Atalar, Taner; Cihaner, Atilla; Algi, FatihA dithienylpyrrole-BODIPY based donor-acceptor system with 1,4-phenylene spacer as a model system for energy transfer was designed and synthesized. Absorption and emission spectra have revealed an efficient resonance energy transfer from dithienylpyrrole as donor to BODIPY as acceptor.Article Connectedness of the Cut System Complex on Nonorientable Surfaces(Univ Kragujevac, Fac Science, 2022) Ali, Fatema; Atalan, FeriheLet N be a compact, connected, nonorientable surface of genus g with n boundary components. In this note, we show that the cut system complex of N is connected for g < 4 and disconnected for g >= 4. We then define a related complex and show that it is connected for g >= 4.Article Citation - WoS: 2Citation - Scopus: 2Comparative Simulation of PI and Fuzzy Control for Fluid Catalytic Cracking Unit(Iranian Institute of Research and Development in Chemical Industries, 2025) Atiyaha, Safa Khalaf; Al-Timimi, Buthainah Ali; Ali, Ahmed Yaseen; Ahmed, Mohamed Salih; Albayati, Talib M.; Abdullah, Ghassan H.; Mel, Maizirwan; Salih Ahmed, MohamedThe fluid catalytic cracking unit converts heavy feedstocks into more valuable gasoline and oil products, representing an essential component in refineries. The variables, including gas oil supply temperature (Tf), gas oil supply flow rate (Ff), and air temperature (Ta), are controlled and manipulated by this unit, which poses a significant challenge due to its complex interactions. To address these complexities, this study investigates the control of riser and regenerator temperatures (TR, TG) in an industrial Universal Oil Products (UOP) fluid catalytic cracking unit using proportional-integral and fuzzy logic controllers. The fuzzy logic controller, with five fuzzy sets generating 25 rules, is implemented through MATLAB simulation. The simulation program is formulated based on the principles of mass and energy balance of the unit. The performance of the controllers, including PI and fuzzy logic controllers, is evaluated and compared by introducing disturbances in the gas oil supply temperature, gas oil supply flow rate, and air temperature. The results show that the fuzzy logic controller outperforms the PI controller, exhibiting a lower integral absolute error. Compared to the PI controller, the fuzzy logic controller demonstrates improved performance, characterized by stable responses and shorter settling times. These findings highlight the effectiveness of the fuzzy logic controller in achieving better control performance for Fluid Catalytic Cracking Units (FCCU).Article Citation - WoS: 12Citation - Scopus: 14Coating of Titanium Implants With Boron Nitride by Rf-Magnetron Sputtering(indian Acad Sciences, 2016) Gokmenoglu, Ceren; Ozmeric, Nurdan; Cakal, Gaye; Dokmetas, Nihan; Ergene, Cansu; Kaftanoglu, BilginSurface modification is necessary for titanium implants since it is unable to induce bone apposition. The beneficial effects of boron on bone formation, composition and physical properties make it suitable as a coating material. In the present study, surface properties of boron nitride (BN) coating on titanium implants were evaluated. Twenty-four implants and 12 abutments were coated with BN by RF-magnetron sputtering system. ATR-FTIR measurements were conducted to assess surface chemistry and morphology of BN-coated implants. Adhesion tests were performed by CSM nanoscratch test device to determine adhesion of BN to titanium surface. Surface profilometry and atomic force microscopy (AFM) was used to evaluate surface roughness. Mean roughness values were calculated. Contact angle measurements were done for evaluation of wettability. Surface characterization of coated implants was repeated after RF power of the system was increased and voltage values were changed to evaluate if these settings have an impact on coating quality. Three different voltage values were used for this purpose. Hexagonal-BN was determined in FTIR spectra. RF-coating technique provided adequate adherence of BN coatings to the titanium surface. A uniform BN coating layer was formed on the titanium implants with no deformation on the titanium surface. Similar roughness values were maintained after BN coating procedure. Before coating, the contact angles of the implants were in between 63(ay) and 79(ay), whereas BN coated implants' contact angles ranged between 46(ay) and 67(ay). BN-coated implant surfaces still have hydrophilic characteristics. The change in voltage values seemed to affect the surface coating characteristics. Especially, the phase of the BN coating was different when different voltages were used. According to our results, BN coating can be sufficiently performed on pretreated implant surfaces and the characteristics of BN coated surfaces can be changed with the change in parameters of RF-magnetron sputtering system.Article Citation - WoS: 1Citation - Scopus: 1Fesenko Reciprocity Map(Amer Mathematical Soc, 2009) Ikeda, K. I.; Serbest, E.In recent papers, Fesenko has defined the non-Abelian local reciprocity map for every totally ramified arithmetically profinite (APF) Galois extension of a given local field K, by extending the work of Hazewinkel and Neukirch-Iwasawa. The theory of Fesenko extends the previous non-Abelian generalizations of local class field theory given by Koch-de Shalit, and by A. Gurevich. In this paper, which is research-expository in nature, we give a detailed account of Fesenko's work, including all the skipped proofs.Article An Application of Stochastic Maximum Principle for a Constrained System With Memory(Ankara Univ, Fac Sci, 2025) Savku, EmelIn this research article, we study a stochastic control problem in a theoretical frame to solve a constrained task under memory impact. The nature of memory is modeled by Stochastic Differential Delay Equations and our state process evolves according to a jump-diffusion process with time-delay. We work on two specific types of constraints, which are described in the stochastic control problem as running gain components. We develop two theorems for corresponding deterministic and stochastic Lagrange multipliers. Furthermore, these theorems are applicable to a wide range of continuous-time stochastic optimal control problems in a diversified scientific area such as Operations Research, Biology, Computer Science, Engineering and Finance. Here, in this work, we apply our results to a financial application to investigate the optimal consumption process of a company via its wealth process with historical performance. We utilize the stochastic maximum principle, which is one of the main methods of continuous-time Stochastic Optimal Control theory. Moreover, we compute a real-valued Lagrange multiplier and clarify the relation between this value and the specified constraint.Conference Object Citation - WoS: 9Citation - Scopus: 12Stochastic Comparisons Between Lifetimes of Reliability Systems With Exchangeable Components(Springer, 2016) Koutras, Markos V.; Triantafyllou, Ioannis S.; Eryilmaz, SerkanIn this article we present several results pertaining to the stochastic comparison of the lifetimes of two reliability systems with exchangeable components. More specifically, we provide signature-based sufficient and necessary conditions for establishing hazard rate and reverse hazard rate orderings. Finally, focusing on the class of consecutive-type systems, we illustrate how the general results can be exploited to deduce several stochastic orderings among members of this class.Conference Object Citation - WoS: 2Citation - Scopus: 1Rational Forms That Imply the Uniqueness of Fixed Points in Partial Metric Spaces(Yokohama Publ, 2019) Karapinar, Erdal; MathematicsIn this paper, we investigate the existence and uniqueness of fixed points of Jaggi type contractions by using a simulation function in the framework of partial metric spaces. Our results improve, extend and unify several results on the topic in the literature.Article Citation - WoS: 11Citation - Scopus: 13Choice Functions for Autonomous Search in Constraint Programming: Ga Vs. Pso(Univ Osijek, Tech Fac, 2013) Soto, Ricardo; Crawford, Broderick; Misra, Sanjay; Palma, Wenceslao; Monfroy, Eric; Castro, Carlos; Paredes, Fernando; Computer EngineeringThe variable and value ordering heuristics are a key element in Constraint Programming. Known together as the enumeration strategy they may have important consequences on the solving process. However, a suitable selection of heuristics is quite hard as their behaviour is complicated to predict. Autonomous search has been recently proposed to handle this concern. The idea is to dynamically replace strategies that exhibit poor performances by more promising ones during the solving process. This replacement is carried out by a choice function, which evaluates a given strategy in a given amount of time via quality indicators. An important phase of this process is performed by an optimizer, which aims at finely tuning the choice function in order to guarantee a precise evaluation of strategies. In this paper we evaluate the performance of two powerful choice functions: the first one supported by a genetic algorithm and the second one by a particle swarm optimizer. We present interesting results and we demonstrate the feasibility of using those optimization techniques for Autonomous Search in a Constraint Programming context.
