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Full-Text Articles in Physical Sciences and Mathematics

On Modules Which Satisfy The Radical Formula, Bülent Saraç, Yücel Tiraş Jan 2013

On Modules Which Satisfy The Radical Formula, Bülent Saraç, Yücel Tiraş

Turkish Journal of Mathematics

In this paper, the authors prove that every representable module over a commutative ring with identity satisfies the radical formula. With this result, they extend the class of modules satisfying the radical formula from that of Artinian modules to a larger one. They conclude their work by giving a description of the radical of a submodule of a representable module.


Generalized Sobolev-Shubin Spaces, Boundedness And Schatten Class Properties Of Toeplitz Operators, Ayşe Sandikçi, Ahmet Turan Gürkanli Jan 2013

Generalized Sobolev-Shubin Spaces, Boundedness And Schatten Class Properties Of Toeplitz Operators, Ayşe Sandikçi, Ahmet Turan Gürkanli

Turkish Journal of Mathematics

Let w and \omega be two weight functions on R^{2d} and 1 \leq p,q \leq \infty. Also let M(p,q,\omega) (R^d) denote the subspace of tempered distributions S' (R^d) consisting of f \in S' (R^d) such that the Gabor transform V_g f of f is in the weighted Lorentz space L(p,q,\omega d\mu) (R^{2d}) . In the present paper we define a space Q_{g,w}^{M(p,q,\omega) (R^d) as counter image of M(p,q,\omega) (R^d) under Toeplitz operator with symbol w. We show that Q_{g,w}^{M(p,q,\omega)}(R^d) is a generalization of usual Sobolev-Shubin space Q_s (R^d). We also investigate the boundedness and Schatten-class properties of Toeplitz operators.


On The Nilpotent Graph Of A Ring, Mohammad Javad Nikmehr, Soheila Khojasteh Jan 2013

On The Nilpotent Graph Of A Ring, Mohammad Javad Nikmehr, Soheila Khojasteh

Turkish Journal of Mathematics

Let R be a ring with unity. The nilpotent graph of R, denoted by \Gamma_N(R), is a graph with vertex set Z_N(R)^* = {0 \neq x \in R \mid xy \in N(R) for some 0 \neq y \in R}; and two distinct vertices x and y are adjacent if and only if xy \in N(R), where N(R) is the set of all nilpotent elements of R. Recently, it has been proved that if R is a left Artinian ring, then diam(\Gamma_N(R)) \leq 3. In this paper, we present a new proof for the above result, where R is a finite …


On Some Results On Ip-Graphs, Roghayeh Hafezieh, Moohammadali Iranmanesh Jan 2013

On Some Results On Ip-Graphs, Roghayeh Hafezieh, Moohammadali Iranmanesh

Turkish Journal of Mathematics

The IP-graph of a naturally valenced association scheme and some of its properties have been studied recently. In this paper we introduce the bipartite version of this graph for a naturally valenced association scheme (X,S), denoted by BIP(S). We also investigate some of its properties.


On The Centroid Of Prime Semirings, Hasret Yazarli, Mehmet Ali̇ Öztürk Jan 2013

On The Centroid Of Prime Semirings, Hasret Yazarli, Mehmet Ali̇ Öztürk

Turkish Journal of Mathematics

We define and study the extended centroid of a prime semiring. We show that the extended centroid is a semifield and give some properties of the centroid of a right multiplicatively cancellable prime semiring.


Finitistic Dimension Conjectures For Representations Of Quivers, Sergio Estrada, Salahatti̇n Özdemi̇r Jan 2013

Finitistic Dimension Conjectures For Representations Of Quivers, Sergio Estrada, Salahatti̇n Özdemi̇r

Turkish Journal of Mathematics

Let R be a ring and Q be a quiver. We prove the first Finitistic Dimension Conjecture to be true for RQ, the path ring of Q over R, provided that R satisfies the conjecture. In fact, we prove that if the little and the big finitistic dimensions of R coincide and equal n


Products Of Conjugacy Classes And Products Of Irreducible Characters In Finite Groups, Mohammad Reza Darafsheh, Sajjad Mahmood Robati Jan 2013

Products Of Conjugacy Classes And Products Of Irreducible Characters In Finite Groups, Mohammad Reza Darafsheh, Sajjad Mahmood Robati

Turkish Journal of Mathematics

Let G be a finite group. If A and B are two conjugacy classes in G, then AB is a union of conjugacy classes in G and \eta(AB) denotes the number of distinct conjugacy classes of G contained in AB. If \chi and \psi are two complex irreducible characters of G, then \chi\psi is a character of G and again we let \eta(\chi\psi) be the number of irreducible characters of G appearing as constituents of \chi\psi. In this paper our aim is to study the product of conjugacy classes in a finite group and obtain an upper bound for \eta …


Global Existence, Decay And Blow Up Solutions For Coupled Nonlinear Wave Equations With Damping And Source Terms, Erhan Pi̇şki̇n, Necat Polat Jan 2013

Global Existence, Decay And Blow Up Solutions For Coupled Nonlinear Wave Equations With Damping And Source Terms, Erhan Pi̇şki̇n, Necat Polat

Turkish Journal of Mathematics

We study the initial-boundary value problem for a system of nonlinear wave equations with nonlinear damping and source terms, in a bounded domain. The decay estimates of the energy function are established by using Nakao's inequality. The nonexistence of global solutions is discussed under some conditions on the given parameters.


Bbm Equation With Non-Constant Coefficients, Amutha Senthilkumar Jan 2013

Bbm Equation With Non-Constant Coefficients, Amutha Senthilkumar

Turkish Journal of Mathematics

In this article, a model for the propagation of long waves over an uneven bottom is considered. We provide both theoretical and numerical results for this model. We also discuss the changes which occur in a solitary wave solution of the BBM equation as it travels through a channel of decreasing depth.


Second Order Approximations In Sequential Point Estimation Of The Probability Of Zero In Poisson Distribution, Eisa Mahmoudi, Mohammad Hatami Kamin Jan 2013

Second Order Approximations In Sequential Point Estimation Of The Probability Of Zero In Poisson Distribution, Eisa Mahmoudi, Mohammad Hatami Kamin

Turkish Journal of Mathematics

In the analysis of the count data, the Poisson model becomes overtly restrictive in the case of over-dispersed or under-dispersed data. When count data are under-dispersed, specific models such as generalized linear models (GLM) are proposed. Other examples are the zero-inflated Poisson model (ZIP) and zero-truncated Poisson model (ZTP), which have been used in literature to deal with an excess or absence of zeros in count data. Thus having a knowledge of the probability of zeros and its estimation in Poisson distribution can be significant and useful. Some estimation problems with unknown parameter cannot attain minimum risk where the sample …


Generalized Derivations Of Prime Rings On Multilinear Polynomials With Annihilator Conditions, Nurcan Argaç, Çağri Demi̇r Jan 2013

Generalized Derivations Of Prime Rings On Multilinear Polynomials With Annihilator Conditions, Nurcan Argaç, Çağri Demi̇r

Turkish Journal of Mathematics

Let K be a commutative ring with unity, R be a prime K-algebra with characteristic not 2, U be the right Utumi quotient ring of R, C the extended centroid of R, I a nonzero right ideal of R and a a fixed element of R. Let g be a generalized derivation of R and f(X_1,..., X_n) a multilinear polynomial over K. If ag(f(x_1,...,x_n))f(x_1,...,x_n)=0 for all x_1,...,x_n \in I, then one of the following holds: (1) aI=ag(I)=0; (2) g(x)=bx+[c,x] for all x\in R, where b,c\in U. In this case either [c,I]I=0=abI or aI=0=a(b+c)I; (3) [f(X_1,...,X_n),X_{n+1}]X_{n+2} is an identity for I.


Strongly Gorenstein Flat And Gorenstein Fp-Injective Modules, Chunhua Yang Jan 2013

Strongly Gorenstein Flat And Gorenstein Fp-Injective Modules, Chunhua Yang

Turkish Journal of Mathematics

In this paper, we first study the properties of strongly Gorenstein flat (resp. Gorenstein FP-injective) modules which are special Gorenstein projective (resp. Gorenstein injective) modules, and use them to prove that the global strongly Gorenstein flat dimension and the global Gorenstein FP-injective dimension of a ring R are identical when R is n-FC or commutative coherent. Finally, we show that if R is a commutative Noetherian ring, then, for any R-module M, SGfd_RM=Gpd_RM, and hence SGfd_RM< \infty if and only if Gfd_RM


Some Properties On The Baer-Invariant Of A Pair Of Groups And V_G-Marginal Series, Mohammad Reza Rismanchian, Mehdi Araskhan Jan 2013

Some Properties On The Baer-Invariant Of A Pair Of Groups And V_G-Marginal Series, Mohammad Reza Rismanchian, Mehdi Araskhan

Turkish Journal of Mathematics

The aim of this paper is to present some properties of the Baer-invariant of a pair of groups with respect to a given variety of groups V. We derive some equalities and inequalities of the Baer-invariant of a pair of finite groups, as long as V is considered to be a Schur-Baer variety. Moreover, we present a relative version of the concept of lower marginal series and give some isomorphisms among V_G-marginal factor groups. Also, we conclude a generalized version of the Stallings' theorem.


(P,\\Lambda)-Koszul Algebras And Modules, Ii, Jiafeng Lu Jan 2013

(P,\\Lambda)-Koszul Algebras And Modules, Ii, Jiafeng Lu

Turkish Journal of Mathematics

This paper is a continuous work of [14], where the notions of (p,\lambda)-Koszul algebra and (p,\lambda)-Koszul module were first introduced. More precisely, some new criteria for a positively graded algebra to be (p,\lambda)-Koszul are provided. We also generalize (p,\lambda)-Koszul objects to the nongraded case and define the so-called quasi-(p,\lambda)-Koszul objects. Further, the relationships between (quasi-) (p,\lambda)-Koszul modules and minimal Horseshoe Lemma are established.


On Nash\'S 4-Sphere And Property 2r, Motoo Tange Jan 2013

On Nash\'S 4-Sphere And Property 2r, Motoo Tange

Turkish Journal of Mathematics

D. Nash defined a family of homotopy 4-spheres in [11]. Proving that his manifolds S_{m,n,m',n'} are all real S^4, we show that they have handle decomposition with no 1-handles, two 2-handles and two 3-handles. The handle structures give new potential counterexamples to the Property 2R conjecture.


Optimal Release Policies For A Software System With Warranty Cost And Change-Point Phenomenon, D.R. Prince Williams Jan 2013

Optimal Release Policies For A Software System With Warranty Cost And Change-Point Phenomenon, D.R. Prince Williams

Turkish Journal of Electrical Engineering and Computer Sciences

Determining the software quality and release time of the software is an important role of software reliability. Software reliability growth models (SRGMs) are applications of software reliability. The change-point is defined as the prominent change in the software testing time, in connection with the quality of a software error occurrence or error-detection phenomenon. As a result, the software reliability growth process, based on the change-point, affects the precision of the software reliability prediction, based on the SRGMs. To find the accurate total expected delivery cost with a suitable warranty period of the software system, a new cost model for the …


Novel Control Strategy For Voltage Source Converters Based On Energy Function, Sanaz Namayan Tavana, Gevork Gharehpetian, Mehrdad Abedi, Ali Bidadfar Jan 2013

Novel Control Strategy For Voltage Source Converters Based On Energy Function, Sanaz Namayan Tavana, Gevork Gharehpetian, Mehrdad Abedi, Ali Bidadfar

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a nonlinear control strategy for pulse-width modulated voltage source converters (VSCs). A passivity-based approach, resulting from the Lyapunov direct method, is presented for designing an effective nonlinear VSC controller to improve their dynamic behaviors under perturbed conditions. The differential equations of the converters are obtained and then transformed into a d-q frame. Considering the nonlinearity of the transformed equations, the Lyapunov direct method is utilized to find a solution to improve the transient response. The time derivative of the Lyapunov function guarantees that increasing its dissipative term will result in the trajectory of the VSC system returning …


Adaptive Control Of A Time-Varying Rotary Servo System Using A Fuzzy Model Reference Learning Controller With Variable Adaptation Gain, Ömer Aydoğdu, Özdemi̇r Alkan Jan 2013

Adaptive Control Of A Time-Varying Rotary Servo System Using A Fuzzy Model Reference Learning Controller With Variable Adaptation Gain, Ömer Aydoğdu, Özdemi̇r Alkan

Turkish Journal of Electrical Engineering and Computer Sciences

The constant parameters in a conventional fuzzy controller lead to a poor performance for time-varying systems. In this study, a fuzzy model reference learning controller (FMRLC) with a newly defined variable adaptation gain is designed and implemented in the adaptive fuzzy control of a time-varying rotary servo (TVRS) system. In the design of the FMRLC, a knowledge-base modification algorithm with variable adaptation gain is used instead of a fuzzy relation table. Hence, it is provided that the learning and adaptation mechanism continuously updates the knowledge base of the adaptive fuzzy controller against any parameter variations, such as changing loads. By …


Optimized Operation And Maintenance Costs To Improve System Reliability By Decreasing The Failure Rate Of Distribution Lines, Hamed Hashemi Dezaki, Seyed Hossein Hosseinian, Hossein Askarian Abyaneh, Seyed Mohammad Mousavi Agah Jan 2013

Optimized Operation And Maintenance Costs To Improve System Reliability By Decreasing The Failure Rate Of Distribution Lines, Hamed Hashemi Dezaki, Seyed Hossein Hosseinian, Hossein Askarian Abyaneh, Seyed Mohammad Mousavi Agah

Turkish Journal of Electrical Engineering and Computer Sciences

Improving distribution system reliability has received a great deal of attention in recent years. Because of the limitation in expected budgets, it is desirable to determine the most efficient strategy to improve system reliability. This paper proposes a novel method to determine the optimized operation and maintenance costs in order to decrease the failure of system components. The proposed objective function includes the average system frequency interruption index (ASIFI) value. To achieve the best strategy to decrease failures of system components, it is necessary to find the minimum value of the objective function, considering the constraints of operation and maintenance …


Model Of A Photovoltaic Panel Emulator In Matlab-Simulink, Hayretti̇n Can Jan 2013

Model Of A Photovoltaic Panel Emulator In Matlab-Simulink, Hayretti̇n Can

Turkish Journal of Electrical Engineering and Computer Sciences

Being able to behave electrically similar to photovoltaic (PV) panels, PV emulator systems make it possible to perform different PV system tests under various operation conditions. In this paper, a model of a PV panel emulator is presented using the Power System Blockset under MATLAB-Simulink. The simulation of the emulator system is developed for testing a controller prior to a real-time implementation. The model can handle the dependence of all of the parameters in the model with respect to solar radiation and temperature. The simulation results show that the output characteristics of the simulator have good agreement with those of …


Improved Hilbert Moment Thermal Qcd Sum Rules For B_S Meson And Stability With Respect To Moment Parameter, Elşen Veli̇, Gülşah Kaya, Arzu Türkan, Eni̇s Yazici Jan 2013

Improved Hilbert Moment Thermal Qcd Sum Rules For B_S Meson And Stability With Respect To Moment Parameter, Elşen Veli̇, Gülşah Kaya, Arzu Türkan, Eni̇s Yazici

Turkish Journal of Physics

In this paper, we deal with the temperature dependence of the leptonic decay constant and mass of B_s meson in the framework of the Hilbert moment QCD sum rule. In our calculations, we improve the thermal QCD sum rules, taking into account the thermal spectral density and the perturbative 2-loop order corrections to the correlation function. Moreover, we investigate the stability of the results with respect to the Hilbert moment parameter. Our numerical calculations demonstrate that the mass and decay constant are insensitive to the variation of temperature up to T \cong 100 MeV; however, after this value, they start …


Effect Of Stepwise Replacement Of Lif By Zno On Structural And Optical Properties Of Lif.B_2o_3 Glasses, Susheel Arora, Virender Kundu, Dev Raj Goyal, Anup Singh Maan Jan 2013

Effect Of Stepwise Replacement Of Lif By Zno On Structural And Optical Properties Of Lif.B_2o_3 Glasses, Susheel Arora, Virender Kundu, Dev Raj Goyal, Anup Singh Maan

Turkish Journal of Physics

Zinc fluoroborate glasses with compositions xZnO.(40 - x) LiF.60B_2O_3 (x = 0, 5, 10, 15, and 20) were synthesized by the melt-quench method. The amorphous nature of the glassy samples was confirmed by XRD analysis. The nature of the bonds formed and the role of various species in the composition of the glasses were examined using FTIR spectroscopy. FTIR analysis showed shifting of an absorption band with the addition of ZnO. A UV-visible study was carried out to calculate the optical band gap energy, E_gIt was found that E_gdecreased with increase in concentration of ZnO up to x = 15 …


The Effect Of Neutron Irradiation On The Properties Of Tl_{0.6}Pb_{0.3}Cd_{0.1}Ba_2ca_2cu_{3}O_{9-Delta} Superconductors, Kareem Ali Jasim, Tariq Jaffar Alwan, Khalid Hadi Mahdi, Hazim Louis Mansour Jan 2013

The Effect Of Neutron Irradiation On The Properties Of Tl_{0.6}Pb_{0.3}Cd_{0.1}Ba_2ca_2cu_{3}O_{9-Delta} Superconductors, Kareem Ali Jasim, Tariq Jaffar Alwan, Khalid Hadi Mahdi, Hazim Louis Mansour

Turkish Journal of Physics

The effect of neutron irradiation on phase purity, crystal structure, and electrical resistivity of Tl_{0.6}Pb_{0.3}Cd_{0.1} Ba_2Ca_2Cu_3O_{9-delta} superconductors has been studied before and after irradiation by electrical resistance measurements and X-ray diffraction techniques. The zero-resistance superconducting transition temperature, T_{c(offset)}, of samples systematically decreases by about 5 K with the increase of neutron irradiation fluence up 18.12 \times 10^{10} n cm^{-2}. The crystalline phases showed that the compounds have 2 phases, a high-Tc phase (1223) and low-Tc phase (1212), in addition to the impurity phase. The irradiation led to a decrease in oxygen content and volume fraction of high-Tc phase (1223).


Equilibrium Shapes And Deformations Of Some Rare Earth Nuclei In Cranked Nilsson-Strutinsky Shell Correction Approach, Antony Joseph, Kizhakkath Kalam Girija Jan 2013

Equilibrium Shapes And Deformations Of Some Rare Earth Nuclei In Cranked Nilsson-Strutinsky Shell Correction Approach, Antony Joseph, Kizhakkath Kalam Girija

Turkish Journal of Physics

The nuclear potential energies of neutron-deficient even-even rare earth nuclei ^{150-160}Dy, ^{150-160}Er, ^{150-160}Yb, ^{158,162,166-176}Hf, ^{160,164-178}W, and ^{162,166,170-180}Os are computed within the framework of the cranked Nilsson--Strutinsky shell correction method. The ground state potential energy surface diagrams of these nuclei are analysed in terms of quadrupole deformation and the triaxiality parameter. The nuclear shapes and deformations in the ground state are found to be functions of Z and N. Even though most of the isotopes in this region seem to be prolate in the ground state, oblate and triaxial shapes are also predicted for some isotopes. It is also found that …


Analyses Of Elastically Scattered Charged Pions From Calcium Isotopes And The ^{48}Ca-^{54}Fe Isotone At 180 Mev, Zuhair Fayyad Mahmoud Shehadeh Jan 2013

Analyses Of Elastically Scattered Charged Pions From Calcium Isotopes And The ^{48}Ca-^{54}Fe Isotone At 180 Mev, Zuhair Fayyad Mahmoud Shehadeh

Turkish Journal of Physics

The elastic scattering of 180 MeV positively and negatively charged pions, incident on a set of calcium isotopes and the isotone ^{48}Ca - ^{54}Fe, has been analyzed within the framework of a recently updated simple local optical potential. This potential, particularly at the tail region, has been originally determined from available phase shifts using inverse scattering theory and the Klein--Gordon equation as a guide. The analysis is carried out with and without considering the squared potential term in the Klein-Gordon equation. Coulomb effects are accounted for by implementing Stricker's prescription. The numerical results for the angular distributions with isotopic and …


A Fission Model Approach To Alpha Decay And Cluster Radioactivity Of Dy, Er, And Yb Isotopes, Kizhakkath Kalam Girija, Antony Joseph Jan 2013

A Fission Model Approach To Alpha Decay And Cluster Radioactivity Of Dy, Er, And Yb Isotopes, Kizhakkath Kalam Girija, Antony Joseph

Turkish Journal of Physics

Rare earth nuclei are probable candidates for exhibiting cluster radioactivity. In the present work, a theoretical study of alpha decay and heavy cluster emission from Dy, Er, and Yb nuclei in the mass range 150 < A < 190 has been carried out in a fission model approach. Some of the proton-rich isotopes of these nuclei are found to have long half-lives, but within the measurable range. Many of the neutron-rich isotopes under consideration are far from beta stability and the most probable light clusters predicted are highly exotic in nature and the corresponding half-lives are extremely short. However, the decays of most probable heavy clusters predicted have half-lives in the measurable range. The calculations on neutron-rich isotopes indicate the emergence of new magic numbers for protons and neutrons. The centrifugal barrier effect on decay rate of some proton-rich Er isotopes is also investigated.


Best Possible Tilt Angle For Optimal Solar Radiation On An Inclined Surface For Photovoltaic And Solar Thermal Application In Yenagoa, Nigeria, Kenneth Priye Ainah, John Tarilanyo Afa Jan 2013

Best Possible Tilt Angle For Optimal Solar Radiation On An Inclined Surface For Photovoltaic And Solar Thermal Application In Yenagoa, Nigeria, Kenneth Priye Ainah, John Tarilanyo Afa

Turkish Journal of Physics

Due to the increased use of solar energy resources globally, the study of the available solar resources is essential for systems that use solar energy. This paper uses the Duffie and Beckhman method for estimating the best possible tilt angle for solar radiation using some climatic data such as declination, latitude, and clear index for photovoltaic and solar thermal systems application in the city of Yenagoa. This research was conducted with different tilt angle ranging from 15° to 65° tilt and it was shown that the best tilt angle for solar energy system application for Yenagoa falls in the range …


Planar Waveguide With Left-Handed Material Guiding Film For Refractometry Applications, Taher M. El-Agez, Sofyan A. Taya, Mohamed M. Shabat, Hani M. Kullab Jan 2013

Planar Waveguide With Left-Handed Material Guiding Film For Refractometry Applications, Taher M. El-Agez, Sofyan A. Taya, Mohamed M. Shabat, Hani M. Kullab

Turkish Journal of Physics

A symmetric 3-layer slab waveguide with a left-handed material as a guiding layer is examined analytically for cover refractive index detection. The TM mode dispersion relation of the proposed waveguide is investigated. The sensitivity of the proposed sensor to changes in the cover refractive index and the power flowing within each layer are presented. Some unusual features are found; for example, the sensitivity of the proposed sensor is negative. Moreover, the sensitivity improvement compared with the conventional 3-layer waveguide sensor is approximately a factor of 6.


Bound States And The Oscillator Strengths For The Klein-Gordon Equation Under Möbius Square Potential, Hassan Hassanabadi, Bentol Hoda Yazarloo, Saber Zarrinkamar Jan 2013

Bound States And The Oscillator Strengths For The Klein-Gordon Equation Under Möbius Square Potential, Hassan Hassanabadi, Bentol Hoda Yazarloo, Saber Zarrinkamar

Turkish Journal of Physics

The Klein-Gordon equation under the equal scalar and vector Möbius square potentials in D-dimensions is solved by using the Nikiforov-Uvarov method. The energy eigenvalues and the corresponding eigenfunctions are obtained and numerically calculated. The oscillator strengths are determined and discussed in terms of parameters of the system.


Theoretical Modeling And Numerical Solutions Of Some Standard Thermoluminescence Detector Crystals, Erdem Uzun Jan 2013

Theoretical Modeling And Numerical Solutions Of Some Standard Thermoluminescence Detector Crystals, Erdem Uzun

Turkish Journal of Physics

MCP-100, MYS-N, MTS-7, MTS-100, and MCP-N standard thermoluminescence detector materials are annealed and irradiated. Glow curves and all trap parameters are determined. For these materials new theoretical energy band models are suggested and differential equations governing the charge carrier traffics are derived. The equations are solved by using computer-based numerical methods. During the simulations, experimental data measured in the previous step are given to computer code as the initial conditions. Experimental and numerical results show that the electron-band structures of standard thermoluminescence crystals are represented fairly well by the suggested models.