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Article Citation - WoS: 4Citation - Scopus: 5An Unconventional Finite Difference Scheme for Modified Korteweg-De Vries Equation(Hindawi Ltd, 2017) Koroglu, Canan; Aydin, AyhanA numerical solution of the modified Korteweg-de Vries (MKdV) equation is presented by using a nonstandard finite difference (NSFD) scheme with theta method which includes the implicit Euler and a Crank-Nicolson type discretization. Local truncation error of the NSFD scheme and linear stability analysis are discussed. To test the accuracy and efficiency of the method, some numerical examples are given. The numerical results of NSFD scheme are compared with the exact solution and a standard finite difference scheme. The numerical results illustrate that the NSFD scheme is a robust numerical tool for the numerical integration of the MKdV equation.Article Citation - WoS: 18Citation - Scopus: 18Growth, Electrical and Structural Characterization of Β-Gase Thin Films(Springer, 2003) Parlak, M; Qasrawi, AF; Erçelebi, ÇGaSe thin films were deposited onto the glass substrates kept at 200degrees and 300degreesC by the thermal evaporation of GaSe crystals under the pressure of 10(-5) Torr. X-ray analysis of the films revealed that films grown at 200. C are amorphous in nature while the films grown at 300degreesC are polycrystalline beta-GaSe. The temperature dependent electrical conductivity measurements in the region of 320-100 K for the films grown at 300degreesC showed that the transport mechanisms are the thermionic emission of charged carriers and the variable range hopping above and below 180 K, respectively. Space charge limited current (SCLC) studies have also been performed on these films through the current-voltage measurements at different temperatures and a dominant hole trap at 0.233 eV from the top of the valance band with a trap density of similar to1.6 x 10(11) cm(-3) is identified. (C) 2003 Kluwer Academic Publishers.Article Citation - WoS: 10Citation - Scopus: 11Strain Engineering of Germanium Nanobeams by Electrostatic Actuation(Nature Portfolio, 2019) Ayan, Arman; Turkay, Deniz; Unlu, Buse; Naghinazhadahmadi, Parisa; Oliaei, Samad Nadimi Bavil; Boztug, Cicek; Yerci, SelcukGermanium (Ge) is a promising material for the development of a light source compatible with the silicon microfabrication technology, even though it is an indirect-bandgap material in its bulk form. Among various techniques suggested to boost the light emission efficiency of Ge, the strain induction is capable of providing the wavelength tunability if the strain is applied via an external force. Here, we introduce a method to control the amount of the axial strain, and therefore the emission wavelength, on a suspended Ge nanobeam by an applied voltage. We demonstrate, based on mechanical and electrical simulations, that axial strains over 4% can be achieved without experiencing any mechanical and/or electrical failure. We also show that the non-uniform strain distribution on the Ge nanobeam as a result of the applied voltage enhances light emission over 6 folds as compared to a Ge nanobeam with a uniform strain distribution. We anticipate that electrostatic actuation of Ge nanobeams provides a suitable platform for the realization of the on-chip tunable-wavelength infrared light sources that can be monolithically integrated on Si chips.Editorial Citation - Scopus: 1Existence and Uniqueness of Fixed Point in Various Abstract Spaces and Related Applications(Hindawi Publishing Corporation, 2015) Karapnar,E.; Du,W.-S.; Kumam,P.; Petruşel,A.; Romaguera,S.[No abstract available]Article Citation - WoS: 13Citation - Scopus: 15Investigation of electrical characteristics of Ag/ZnO/Si sandwich structure(Springer, 2019) Gullu, H. H.; Surucu, O. Bayrakli; Terlemezoglu, M.; Yildiz, D. E.; Parlak, M.; Bayraklı Sürücü, Ö.In this study, temperature-dependent current-voltage (I-V), frequency-dependent capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements are carried out for the electrical characterization of a zinc oxide (ZnO) thin film-based diode. The sandwich structure in the form of Ag/ZnO/Si/Al is investigated at temperatures between 220 and 360 K and in the frequency region of 1 kHz-1 MHz. ZnO thin film layer is deposited on a p-Si wafer substrate as a transparent conductive oxide layer by taking into consideration possible electronic applications with intrinsic attractive material properties. At each temperature step, the I-V curves showed about two orders of magnitude rectifying behavior and, according to the Schottky diode relation, the saturation current, zero-bias barrier height and ideality factor were extracted as a function of the temperature. In the case of non-ideal diode characteristics due to the inhomogeneties in the diode as observed from the characteristics of the calculated parameters, effective barrier height values are evaluated. In addition, based on the existence of the interface layer, density of interface states in the band gap region and parasitic resistances were determined by the capacitance measurements.Book Part Citation - WoS: 1Citation - Scopus: 2Bamboo Fiber-Reinforced Composites(Igi Global, 2016) Sanal, IremNowadays, there has been an increased interest in the applications of bio-composites based on natural fibers, with the increasing emphasis on materials and processes which are environmental friendly and sustainable. Environmental friendly, fully biodegradable reinforced polymers or `green' composite materials will play a major role in making the products of the future to protect our environment. The use of biodegradable and environment-friendly plant-based natural fibers has been a promising choice for polymers to make them `greener'. In addition to being obtained from renewable sources, natural fibers suitable for composites are biodegradable and have enhanced properties. Bamboo is an excellent example for the development of sustainable natural fibers, since it can grow very fast per day, and the fibers of bamboo have excellent mechanical performance. Additionally, research in the development of bamboo-reinforced composites should be increased in the future, considering their enhanced properties, economical benefits and environmental friendly nature.Article Citation - WoS: 1Citation - Scopus: 1Experimental Determination of Resistance Characteristics of Support Details Used in Prestressed Concrete Bridge Girders(Asce-amer Soc Civil Engineers, 2009) Baran, Eray; Rohne, Ryan; French, Catherine E.; Schultz, Arturo E.Static load tests were performed on support details used at the ends of prestressed concrete pedestrian bridge girders to determine the resistance characteristics of girder supports in the direction perpendicular to the longitudinal axis of the girders. The specimens tested represent support details that have also been widely used in prestressed concrete highway bridges in Minnesota and in other states. Two specimens, one representing the free-end detail and one representing the restrained-end detail were subjected to a combination of vertical and lateral loads. The applied loading was intended to simulate the loading conditions to which the girder ends would be subjected in the event of an over-height vehicle collision with the bridge. The tests revealed two types of lateral load resisting mechanisms depending on the type of support detail. The specimen with the free-end detail resisted the lateral loading through sliding friction between the components of the support assembly. Deformation of this specimen was a combination of shear deformation of the bearing pad and sliding of various support components. The restrained-end detail exhibited larger lateral load capacity than the free-end detail due to the resistance provided by the anchor rods that were intended to prevent the lateral movement of the girder ends. Failure of the specimen with restrained-end detail was due to the concrete breakout and bending of the anchor rods.Conference Object Citation - Scopus: 2Handling Nat Traversal and Mobility for Multimedia Traffic(2006) Gaylani,N.; Erten,Y.M.Network Address Translator (NAT) traversal is a problem for many applications because a host in a private network cannot be contacted by a node which is outside this network unless the communication is initiated by the host itself. This restriction poses further problems when one of the hosts moves during an active session to a new location which is also behind a NAT. In this study we have proposed solutions to the above problems based on Mobile IP and SIP messaging. Our solutions are based on hole punching and the assumption that the hosts already know the details of each other. Hence it will not be required to consult the proxy or location servers when reestablishing the communication and this should reduce the required handoff time. © 2006 IEEE.Article Efficient New Process Uses Kinematic Male Parts: Rapid Prototyping in Sheet Metal Forming;(2009) Franzen,V.; Sebastiani,G.; Kwiatkowski,L.; Brosius,A.; Erman Tekkaya,A.; Shankar,R.[No abstract available]Conference Object Transmutation of Minor Actinides in Candu Reactors(2010) Şahin,S.; Şahin,H.M.; Acir,A.; Al-Kusayer,T.A.Large quantities of nuclear waste plutonium have been accumulated in the civilian LWRs and CANDU reactors in form of minor actinides (MAs). Reactor grade plutonium and other transuranium elements can be used as a booster fissile fuel material in form of mixed ThO2/MAO2 fuel in a CANDU fuel bundle in order to assure reactor criticality. Following fuel compositions have been selected for investigations; Reactor grade plutonium: Circled digit one 96 % thoria (ThO2) + 4 % PuO2 and Circled digit two 91 % ThO2 + 5 % UO2 + 4 % PuO2. The latter is used for the purpose of denaturing the new 233U fuel with 238U. The behavior of the criticality k∞ and the burn-up values of the reactor have been pursued by full power operation for > ∼ 8 years. The reactor starts with k∞ = ∼ 1.39 and the criticality drops down asymptotically to values k∞ > 1.06, still acceptable and useable in a CANDU reactor. Reactor criticality k ∞ remains nearly constant between the 4th year and 7th year of plant operation and then a slight increase is observed thereafter, along with a continuous depletion of thorium fuel. Totality of nuclear waste actinides after the extraction of uranium isotopes: The best fuel compositions with respect to power flattening as well as long term reactivity have been found by mixing thoria with 14 % minor actinides in form of MAO 2 in the central fuel bundle and decreasing the MAO2 content in radial direction at discrete levels down to 2 % at the periphery. The temporal variation of the criticality k∞ and the burn-up values of the reactor have been calculated for a period of 10 years, operated at full power. The criticality starts at time zero near to k∞ = ∼ 1.24 for both fuel compositions. A sharp decrease of the criticality has been observed during the first year as a consequence of rapid plutonium burnout in the actinide fuel. The criticality becomes quasi constant after the 2 nd year after sufficient 233U is accumulated and remains close to k∞,end = ∼1.06 over ∼ 10 years. Quasi-uniform power generation density has been realized in the fuel bundle throughout the reactor operation. In all investigated cases, plutonium burns up rapidly and after the 2nd year, the CANDU reactor begins to operate practically as a thorium burner.
