Akademik Çıktılar

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A Petri Net-based inference network for design automation under nondeterminism applied to mechatronic systems
(Pergamon Press Ltd, 1998) Erden, Z; Erkmen, AM; Erden, A
This paper introduces the completed part of an ongoing research, in which a Petri Net-based design inference network is developed for the representation and analysis of the functions and their interrelationships through information flow for the conceptual design stage of mechatronic systems in order to facilitate design automation. The theoretical framework behind the network is based on transition of Hybrid Automata into Petri Nets and application of this framework is introduced by a mechatronic design example.
Sputtering yield and dynamical analysis of Ni(100) surface: A comparison of four different Ar-surface interaction potentials
(Elsevier Science Bv, 2000) Güvenç, ZB; Hundur, Y; Hippler, R
The sputtering process of the Ar + Ni(100) collision system is investigated by means of constant energy molecular dynamics simulations. The Ni(100) is mimicked by an embedded-atom potential, and the interaction between the projectile and the surface is modelled by using four different screened Coulomb type potentials. The Ni atom emission from the lattice is analysed over the range of 10-40 eV collision energy. The maximum penetration depths of Ar, probability distributions of kinetic energy of the reflected Ar, and energy of the Ar and sputtered Ni atoms in the same collision events are evaluated as functions of the impact energy and sputtering time. Further, angular distributions of the scattered Ar are obtained. The calculated sputtering yields are compared with the available theoretical and experimental data. (C) 2000 Elsevier Science B.V. All rights reserved.
Geometrization of the Lax pair tensors
(World Scientific Publ Co Pte Ltd, 2000) Baleanu, D; Baleanu, Dumitru; Baskal, S; 56389
The tensorial form of the Lax pair equations are given in a compact and geometrically transparent form in the presence of Cartan's torsion tensor. Three-dimensional space-times admitting Lax tensors are analyzed in detail. Solutions to Lax tensor equations include interesting examples as separable coordinates and the Toda lattice.
Reactions of small Ni clusters with a diatomic molecule: MD simulation of D(2)+Ni(n) (n=7-10) systems
(Elsevier Science Bv, 2000) Durmus, P; Böyükata, M; Özçelik, S; Güvenç, ZB; Jellinek, J
The kinetics of the reactions of nickel clusters with a deuterium molecule are studied, Dissociative chemisorption probabilities of the D(2) molecule on the small Ni(n) (n=7-10) clusters are computed by a quasi-classical molecular dynamics computer simulation technique. Structures of the clusters are obtained by an embedded-atom potential, and the interaction between the D(2) and Ni(n) is modelled by an LEPS (London-Eyring-Polanyi-Sato) function (energy surface). This analysis includes the chemisorption probabilities as functions of the impact parameter and of the relative translational energy of the D(2). The corresponding reactive cross-sections for the ground state of the molecule are calculated as functions of the collision energy and the size of the cluster. The role of the size of the clusters is examined. An indirect mechanism to the reaction, which involves formation of molecular adsorption as precursors to dissociative adsorption in the low collision energy region (less than 0.1eV), is observed. Results are discussed by comparing with the other similar theoretical and experimental studies. (C) 2000 Elsevier Science B.V. All rights reserved.
Lax tensors and separable coordinates in (2+1) dimensions
(inst Physics Acad Sci Czech Republic, 2000) Baleanu, D; Baleanu, Dumitru; Baskal, S; 56389
We study the Lax tensors of the separable coordinates in (2+1) dimensions. The Lax tensors of the dual manifolds are investigated.
Finite size scaling by using scaling functions in two-dimensional q = 2 and 7 state Potts models
(World Scientific Publ Co Pte Ltd, 2001) Demirtürk, S; Aydın, Meral; Seferoglu, N; Aydin, M; Gündüç, Y
The scaling behaviors of the percolation cumulant and the surface renormalization are studied on q = 2 and 7 state Potts models. The results show that the scaling functions can be safely used to determine infinite lattice transition points and the thermal and magnetic exponents indicating that these functions have very small correction to scaling contributions.
Multi-Hamilton-Jacobi quantization of O(3) nonlinear sigma model
(World Scientific Publ Co Pte Ltd, 2001) Baleanu, Dumitru; Baleanu, D; Güler, W; Güler, Yurdahan; 56389
The O(3) nonlinear sigma model is investigated using multi-Hamilton-Jacobi formalism. The integrability conditions are investigated and the results are in agreement with those obtained by Dirac's method. By choosing an adequate extension of phase space we describe the transformed system by a set of three Hamilton-Jacobi equations and calculate the corresponding action.
Hamilton-Jacobi treatment of chiral schwinger model
(Kluwer Academic/plenum Publ, 2001) Baleanu, D; Baleanu, Dumitru; Güler, Y; 56389
We investigate the path integral quantization of the bosonic chiral Schwinger model using multi-Hamilton-Jacobi procedure. The integrability conditions require the extension of the initial phase space. The Wess-Zumino term was recovered calculating the action corresponding to the extended system.
Chemometric quantitative analysis of pyridoxine HCl and thiamine HCl in a vitamin combination by principal component analysis, classical least squares, and inverse least squares techniques
(Marcel dekker inc, 2001) Dinç, E; Baleanu, Dumitru; Baleanu, D; Onur, F; 56389
Three chemometric techniques were described for the analysis of pyridoxine hydrochloride and thiamine hydrochloride within a vitamin combination in the presence of spectral interferences. For these techniques, the training set was prepared by using synthetic mixtures containing two vitamins in multiple possible combinations for the range of 8-40 mu /mL in 0.1 M HCl. The absorbance values for the training set were obtained by direct measurements at 18 wavelengths in the region 222-305 nm for the zero order spectra. The numerical values were calculated by using the 'Maple V' software. Mean recoveries and relative standard deviations for the principal component analysis, classical least squares and inverse least squares techniques were found as 100.7% and 0.95%; 100.5% and 1.38% and, 99.3% and 1.04 for pyridoxine hydrochloride; and 99.7% and 1.03%; 99.1% and 1.05% and, 99.6% and 1.58% for thiamine hydrochloride, respectively. These three chemometric techniques were successfully applied to vitamin tablets marketed in Turkey. The results were compared with each other and good coincidence was observed.
Hamilton-Jacobi quantization of constrained systems
(inst Physics Acad Sci Czech Republic, 2001) Baleanu, D; Baleanu, Dumitru; Güler, Y; 56389
The path integral quantization of contrained systems is analysed using Hamilton-Jacobi formalism. The integrability conditions are investigated and the results are in agreement with those obtained by Dirac's method.
Eley-Rideal and hot atom reactions between hydrogen atoms on Ni(100): electronic structure and quasiclassical studies
(Amer inst Physics, 2001) Guvenc, ZB; Sha, XW; Jackson, B
The reactions of gas-phase H (or D) atoms with D (or H) atoms adsorbed onto a Ni(100) surface are studied. Electronic structure calculations based on density functional theory are used to examine the interaction of H atoms with the Ni(100) surface, as well as the interactions between two H atoms near the metal surface. A model potential-energy surface based on ideas from effective medium theory is fit to the results of these electronic structure calculations. Quasiclassical trajectory methods are used to simulate the interaction of low energy H and D atom beams with H and D-covered Ni(100) surfaces. It is found that hot-atom processes dominate the formation of molecular hydrogen. The distribution of energy in the product molecules is examined with regard to the various pathways available for reaction. The initial adsorbate coverage is varied and is shown to control the relative amounts of reflection, reaction, sticking, and subsurface penetration. Our results are compared with those from similar studies on Cu(111) and available experimental data for Ni(100). (C) 2001 American Institute of Physics.
Hamilton-Jacobi treatment of a non-relativistic particle on a curved space
(Iop Publishing Ltd, 2001) Baleanu, Dumitru; Baleanu, D; Güler, Y; Güler, Yurdahan; 56389
In this paper a non-relativistic particle moving on a hypersurface in a curved space and the multidimensional rotator are investigated using the Hamilton-Jacobi formalism. The equivalence with the Dirac Hamiltonian formalism is demonstrated in both Cartesian and curvilinear coordinates. The energy spectrum of the multidimensional rotator is equal to that of a pure Laplace-Beltrami operator with no additional constant arising from the curvature of the sphere.
Nonnormal regression. i. skew distributions
(Taylor & Francis inc, 2001) Islam, MQ; Tiku, ML; Yildirim, F
In a linear regression model of the type y = thetaX + e, it is often assumed that the random error e is normally distributed. In numerous situations, e.g., when y measures life times or reaction times, e typically has a skew distribution. We consider two important families of skew distributions, (a) Weibull with support IR: (0, infinity) on the real line, and (b) generalised logistic with support IR: (-infinity, infinity). Since the maximum likelihood estimators are intractable in these situations, we derive modified likelihood estimators which have explicit algebraic forms and are, therefore, easy to compute. We show that these estimators are remarkably efficient, and robust. We develop hypothesis testing procedures and give a real life example.
Nonnormal regression. II. Symmetric distributions
(Taylor & Francis inc, 2001) Tiku, ML; Islam, MQ; Selçuk, AS
Salient features of a family of short-tailed symmetric distributions, introduced recently by Tiku and Vaughan [1], are enunciated. Assuming the error distribution to be one of this family, the methodology of modified likelihood is used to derive MML estimators of parameters in a linear regression model. The estimators are shown to be efficient, and robust to inliers. This paper is essentially the first to achieve robustness to infers. The methodology is extended to long-tailed symmetric distributions and the resulting estimators are shown to be efficient, and robust to outliers. This paper should be read in conjunction with Islam et al. [2] who develop modified likelihood methodology for skew distributions in the context of linear regression.
Dual metrics for a class of radiative space-times
(World Scientific Publ Co Pte Ltd, 2001) Baleanu, D; Baleanu, Dumitru; Baskal, S; 56389
Second-rank nondegenerate Killing tensors for some subclasses of space-times admitting parallel null one-planes ace investigated. Lichnerowicz radiation conditions are imposed to provide a physical meaning to space-times whose metrics are described through their associated second-rank Killing tensors. Conditions under which the dual space-times retain the same physical properties are presented.
Fragmentation of water clusters: molecular-dynamics simulation study
(Springer-verlag, 2001) Erkoç, S; Kökten, H; Güvenç, Z
The fragmentation of water clusters, [(H2O)(n): n = 2-8], have been investigated by using molecular-dynamics simulation method. In the simulations a polarizable-dissociable potential energy function for water has been used. Particular attention has been paid to investigate the effect of structural properties and cluster size of the fragmentation.
Structure and reactivity of Ni(n) (n=7-14, 19) clusters
(Wiley, 2001) Böyükata, M; Güvenç, ZB; Özçelik, S; Durmus, P; Jellinek, J
Results of a computer simulation study of Ni-n (n = 7-14, 19) clusters, their structures, energetics, and reactivity with a D-2 molecule are presented. The clusters are described by an embedded atom potential, whereas the interaction between the molecule and the clusters is modeled by an LEPS (London-Eyring-Polanyi-Sato) potential energy function. The focus is on structures of the dusters and their reactive channels. The total numbers of stable isomers of the clusters are obtained by sampling their phase space, and the isomers' energy spectra are determined. On the reactive side, dissociative chemisorptions cross sections and decay-rate constants are calculated. (C) 2001 John Wiley & Sons, Inc.
Dynamics of the D(2)+Ni(100) collision system: Analysis of the reactive and inelastic channels
(Wiley-blackwell, 2001) Böyükata, M; Güvenç, ZB; Jackson, B; Jellinek, J
The reactive and scattering channels of the D(2)(v, j) + Ni(100) collision system are studied using quasiclassical molecular dynamics simulations. The interaction between the D(2) and the atoms of the surface is modeled by a LEPS (London-Eyring-Polani-Sato) potential energy function. The molecule is aimed at three different impact sites (atop, bridge, and center) of a rigid Ni(100) surface along the normal direction with various collision energies less than or equal to1.0 eV. Dissociative chemisorption probabilities are computed for different rotational states of the molecule. Probability distributions of the final rovibrational states of the ground-state Dp molecule scattered from those impact sites are also computed as a function of the collision energy. Higher collision energy results in excitation of higher rotational and/or vibrational states of the scattered molecule. At collision energies below 0.1 eV an indirect dissociation mechanism (through molecular adsorption) dominates the reaction. (C) 2001 John Wiley & Sons, Inc.
The hamilton-jacobi treatment of supersymmetric quantum mechanics
(World Scientific Publ Co Pte Ltd, 2001) Baleanu, Dumitru; Baleanu, D; Güler, Y; Güler, Yurdahan; 56389
We study the Hamilton-Jacobi quantization of supersymmetric quantum mechanics. The equations of motion of the Grassmann variables are obtained from the integrability conditions. The results are in agreement with those obtained by Dirac's procedure.
Spectrophotometric multicomponent analysis of a mixture of metamizol, acetaminophen and caffeine in pharmaceutical formulations by two chemometric techniques
(Pergamon-elsevier Science Ltd, 2001) Dinç, E; Baleanu, Dumitru; Baleanu, D; Onur, F; 56389
Inverse least squares (ILS) and factor-based (principal component analysis (PCA)) techniques were proposed for the spectrophotometric multicomponent analysis of a ternary mixture consisting of metamizol, acetaminophen and caffeine, without prior separation. In these chemometric techniques, the measurements of the absorbance values were realized in the spectral range from 225 to 285 nm in the intervals of Delta lambda = 5 nm at the 13 wavelengths in the zero-order spectra of the different ternary mixtures of these active ingredients in 0.1 M HCl. The prepared calibrations of both techniques using the absorbance data and concentration matrix data sets were used to predict the concentration of the unknown concentrations of metamizol acetaminophen and caffeine in their ternary mixture. The 'MAPLE V' software was used for the numerical calculations, Mean recoveries and relative standard deviations for ILS and PCA techniques were found to be 99.8 and 1.68%, 99.9 and 1,66% for caffeine, 99.8 and 1.84%, 100.4 and 2.85% for metamizol, and 99.7 and 1.04%, 99.6 and 1.34/ for acetaminophen, respectively, for the first and second techniques. The techniques were successfully applied to two pharmaceutical formulations marketed in Turkey and results were compared with a new high-performance liquid chromatography method. (C) 2001 Elsevier Science B.V. All rights reserved.

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