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Articles 421 - 448 of 448
Full-Text Articles in Physical Sciences and Mathematics
Morphism Classes Producing (Weak) Grothendieck Topologies, (Weak) Lawvere--Tierney Topologies, And Universal Closure Operations, Seyed Naser Hosseini, Mehdi Nodehi
Morphism Classes Producing (Weak) Grothendieck Topologies, (Weak) Lawvere--Tierney Topologies, And Universal Closure Operations, Seyed Naser Hosseini, Mehdi Nodehi
Turkish Journal of Mathematics
In this article, given a category X, with \Omega the subobject classifier in Set^{X^{op}, we set up a one-to-one correspondence between certain (i) classes of X-morphisms, (ii) \Omega-subpresheaves, (iii) \Omega-automorphisms, and (iv) universal operators. As a result we give necessary and sufficient conditions on a morphism class so that the associated (i) \Omega-subpresheaf is a (weak) Grothendieck topology, (ii) \Omega-automorphism is a (weak) Lawvere--Tierney topology, and (iii) universal operation is an (idempotent) universal closure operation. We also finally give several examples of morphism classes yielding (weak) Grothendieck topologies, (weak) Lawvere--Tierney topologies, and (idempotent) universal closure operations.
Quasinormability And Diametral Dimension, Ahmet Tosun Terzi̇oğlu
Quasinormability And Diametral Dimension, Ahmet Tosun Terzi̇oğlu
Turkish Journal of Mathematics
Two versions of diametral dimension are shown to coincide for quasinormable Fréchet spaces. The diametral dimension is determined by a single bounded subset in certain cases.
Complete Cotorsion Pairs In The Category Of Complexes, Zhanping Wang, Zhongkui Liu
Complete Cotorsion Pairs In The Category Of Complexes, Zhanping Wang, Zhongkui Liu
Turkish Journal of Mathematics
In this paper, we study completeness of cotorsion pairs in the category of complexes of R-modules. Let (A, B) be a cotorsion pair in R-Mod. It is shown that the cotorsion pair (\widetilde{A}, dg\widetilde{B}) and (\overline{A}, \overline{A}^{\perp}) are complete if A is closed under pure submodules and cokernels of pure monomorphisms, where in Gillespie's definitions \widetilde{A} is the class of exact complexes with cycles in A and dg\widetilde{B} is the class of complexes X with components in B such that the complex Hom(A, X) is exact for every complex A \in \widetilde{A}; and \overline{A} is the class of all complexes …
Slant Submersions From Almost Product Riemannian Manifolds, Yilmaz Gündüzalp
Slant Submersions From Almost Product Riemannian Manifolds, Yilmaz Gündüzalp
Turkish Journal of Mathematics
In this paper, we define the concept of almost product Riemannian submersion between almost product Riemannian manifolds. We introduce slant submersions from almost product Riemannian manifolds onto Riemannian manifolds. We give examples and investigate the geometry of foliations that arise from the definition of a Riemannian submersion. We also find necessary and sufficient conditions for a slant submersion to be totally geodesic.
Factorization Of Composite Polynomials Over Finite Fields, Saeid Mehrabi
Factorization Of Composite Polynomials Over Finite Fields, Saeid Mehrabi
Turkish Journal of Mathematics
This paper presents the reducibility of some composite polynomials and explicitly determines the factorization over finite fields. Also families of irreducible polynomials over finite fields are introduced.
A Class Of 3-Dimensional Almost Cosymplectic Manifolds, İrem Küpeli̇ Erken, Cengi̇zhan Murathan
A Class Of 3-Dimensional Almost Cosymplectic Manifolds, İrem Küpeli̇ Erken, Cengi̇zhan Murathan
Turkish Journal of Mathematics
The main interest of the present paper is to classify the almost cosymplectic 3-manifolds that satisfy \Vert grad\lambda \Vert = const.(\neq 0) and \bigtriangledown_{\xi} h=2ah\phi.
Remarks On The Paper ``On Some New Inequalities For Convex Functions\\" By M. Tunç, Alfred Witkowski
Remarks On The Paper ``On Some New Inequalities For Convex Functions\\" By M. Tunç, Alfred Witkowski
Turkish Journal of Mathematics
In this note, we slightly generalize Theorem 2 in the paper by M. Tunç and point out that the assumption of Theorem 3 is not sufficient. A misuse of the term 'mean' is also discussed.
On The Pollard Decomposition Method Applied To Some Jacobi--Sobolev Expansions, Francisco Marcellán, Yamilet Quintana, Alejandro Urieles
On The Pollard Decomposition Method Applied To Some Jacobi--Sobolev Expansions, Francisco Marcellán, Yamilet Quintana, Alejandro Urieles
Turkish Journal of Mathematics
Let {q_n^{(\alpha,\beta)}}_{n \geq 0} be the sequence of polynomials orthonormal with respect to the Sobolev inner product \langle f,g\rangle_S:=\int_{-1}^1f(x)g(x)w^{(\alpha,\beta)}(x)dx+\int_{-1}^1f'(x)g'(x)w^{(\alpha+1,\beta+1)}(x)dx, where w^{(\alpha,\beta)}(x)=(1-x)^{\alpha}(1+x)^{\beta}, x\in [-1,1] and \alpha,\beta>-1. This paper explores the convergence in the W^{1,p}\left((-1,1), (w^{(\alpha,\beta)},w^{(\alpha+1,\beta+1)})\right) norm of the Fourier expansion in terms of {q_n^{(\alpha,\beta)}}_{n\geq 0} with 1< p
Colombeau Solutions Of A Nonlinear Stochastic Predator--Prey Equation, Uluğ Çapar
Colombeau Solutions Of A Nonlinear Stochastic Predator--Prey Equation, Uluğ Çapar
Turkish Journal of Mathematics
The solution of a random semilinear hyperbolic system with singular initial data is sought as a random Colombeau distribution. The product of 2 additive white noises is well tackled within the theory of random Colombeau distributions. In the special case of a random predator--prey system, the exact Colombeau solution is obtained under some assumptions when the process is driven by doubly reflected Brownian motions.
Some Results On Cyclic Codes Over The Ring R_{2,M}, Reza Sobhani, Maryam Molakarimi
Some Results On Cyclic Codes Over The Ring R_{2,M}, Reza Sobhani, Maryam Molakarimi
Turkish Journal of Mathematics
Let R_{k,m} be the ring F_{2^m}[u_1,u_2,...,u_k]/\gen u_i^2, u_iu_j-u_ju_i. In this paper, cyclic codes of arbitrary length n over the ring R_{2,m} are completely characterized in terms of unique generators and a way for determination of these generators is investigated. A F_{2^m}-basis for these codes is also derived from this representation. Moreover, it is proven that there exists a one-to-one correspondence between cyclic codes of length 2n, n odd, over the ring R_{k-1,m} and cyclic codes of length n over the ring R_{k,m}. By determining the complete structure of cyclic codes of length 2 over R_{2,m}, a mass formula for the …
Symmetry And The Order Of Events In Time: Description Of A Reversible Thermal Energy Converter Composed Of Negative Mass, Randy Wayne
Turkish Journal of Physics
In a previous paper [1], we analyzed the sequence of events that occurs in the time domain of a reversible cyclical thermal energy converter using the Gibbs equation and showed that even when there is no net change of entropy there is an asymmetrical order of quasi-static states along the time axis, when thermal energy is converted into mechanical pressure-volume work. The spontaneous evolution towards an equilibrium state, which is characterized by the unidirectional transport of entropy from the hot reservoir to the cold reservoir, is coincident with this asymmetrical order of events. In this paper, we \"mend\" the above …
Thermodynamic Properties Of The Noncommutative Black Hole In (Z = 3)-Horava-Lifshitz Gravity, Mourad Nach, Khadija Bilal, My Brahim Sedra, Abderrahman El Boukili
Thermodynamic Properties Of The Noncommutative Black Hole In (Z = 3)-Horava-Lifshitz Gravity, Mourad Nach, Khadija Bilal, My Brahim Sedra, Abderrahman El Boukili
Turkish Journal of Physics
In this work, we investigate the effects of noncommutative spaces on the Horava-Lifshitz black hole. We construct the black hole solutions in the noncommutative space of (z = 3)-Horava-Lifshitz gravity. We calculate the horizon and the thermodynamic properties such as the Hawking temperature, the ADM-Mass, and entropy, which reduce to their commutative limits when the noncommutativity parameter tends to zero.
Spin-One Dkp Equation In The Presence Of Nonminimal Vector Woods-Saxon Potential In (1 + 1) Dimensions, Hassan Hassanabadi, Zahra Molaee, Saber Zarrinkamar
Spin-One Dkp Equation In The Presence Of Nonminimal Vector Woods-Saxon Potential In (1 + 1) Dimensions, Hassan Hassanabadi, Zahra Molaee, Saber Zarrinkamar
Turkish Journal of Physics
The Duffin-Kemmer-Petiau equation in the presence of a nonminimal vector Woods-Saxon potential is solved for spin-one particles via the Nikiforov-Uvarov method. The reflection and transmission coefficients of the general form of the DKP equation in the presence of a nonminimal vector interaction are discussed.
Investigation Of Dominant States In The Collisions Of Ar Vii And Kr Xxiv With H_2 And He Targets, Abdel Aziz Habib, Alaa Abo Zalam, Hassan Ramadan
Investigation Of Dominant States In The Collisions Of Ar Vii And Kr Xxiv With H_2 And He Targets, Abdel Aziz Habib, Alaa Abo Zalam, Hassan Ramadan
Turkish Journal of Physics
In thermal plasma, the ion--atom collisions proceed most probably through resonance processes. One of the important processes is the resonant transfer excitation followed by emission of X-rays (RTEX), which causes self-cooling for plasma. In addition, it is identical to the dielectronic recombination (DR) in electron-ion collisions. The present work deals with the calculation of DR cross-sections (\sigma^{DR}s) and DR rate coefficients (\alpha^{DR}s) as well as RTEX cross-sections (\sigma^{RTEX}s) for Mg-like ions [Ar^{6+} and Kr^{24+}] with L-shell and K-shell excitation for \Deltan = 0 and \Delta n \neq 0. Comparison between the present results and other calculations for the rates are …
Study Of Zone Center Phonons In Wolframite Znwo_4, Ruby Jindal, Murari Mohan Sinha, Hem Chandra Gupta
Study Of Zone Center Phonons In Wolframite Znwo_4, Ruby Jindal, Murari Mohan Sinha, Hem Chandra Gupta
Turkish Journal of Physics
A short-range force constant model was applied to investigate the phonons in wolframite ZnWO_4 crystals in their monoclinic phase having space group P2/c and symmetry C_{2h}. The normal symmetry coordinates for the monoclinic wolframite were computed. The zone center phonons were calculated by using 8 stretching and 6 bending force constants. The calculated results are in very good agreement with the observed ones. The infrared frequencies were assigned for the first time. The potential energy distribution was also investigated for determining the significance of the contribution from each force constant toward the Raman and infrared wavenumbers.
A Simple Method To Extract The Parameters Of The Single-Diode Model Of A Pv System, Ahmed A. El Tayyan
A Simple Method To Extract The Parameters Of The Single-Diode Model Of A Pv System, Ahmed A. El Tayyan
Turkish Journal of Physics
This article suggests a simple method of modeling and simulation of photovoltaic systems. The main goal is to find the parameters (I_{ph}, I_o, R_s, R_{sh}, and a) of the single-diode model by adjusting the P-V curve and/or I-V curve at parameters provided by the manufacturer specification sheets (I_{sc}, V_{oc}, I_{mp}, and V_{mp}). An empirical model is incorporated into the single-diode model in order to remove its implicit nature and to ease the calculations. Calculations using this method can be extended to generate the I-V curves at temperatures and irradiances other than the standard test condition (STC)
Study Of Solid-State Stability Of The Zoto Binary System, Sandeep A. Waghuley
Study Of Solid-State Stability Of The Zoto Binary System, Sandeep A. Waghuley
Turkish Journal of Physics
The ZOTO binary system contains different compositions of zinc oxide (ZnO) and tin oxide (SnO_2). These are important semiconductors and have been intensively explored for various applications. SnO_2, ZnO, and different mole ratios (70:30, 40:60, 30:70, and 20:80 SnO_2:ZnO) of the ZOTO system were prepared through proper thermal treatment in powder form. The comparative solid-state stability was investigated using thermogravimetric and differential thermal analysis (TG-DTA). The stability study showed that the SnO_2 material absorbs much lower heat (Ea = -72.06 kJ/g mol) compared with ZnO and their compositions. Thus the SnO_2 material shows stability at near room temperature operation. The …
Molecular Dynamic Simulation On Iron Corrosion-Reduction In High Temperature Molten Lead-Bismuth Eutectic, Artoto Arkundato, Zaki Su'ud, Mikrajuddin Abdullah, Widayani Sutrisno
Molecular Dynamic Simulation On Iron Corrosion-Reduction In High Temperature Molten Lead-Bismuth Eutectic, Artoto Arkundato, Zaki Su'ud, Mikrajuddin Abdullah, Widayani Sutrisno
Turkish Journal of Physics
Molecular dynamic simulation on iron in high-temperature molten lead-bismuth eutectic has been carried out to investigate the iron corrosion and its mitigation. The aim of the work is to investigate the corrosion and evaluate proper oxygen content of injection for significant and effective reduction. To study the phenomena we calculated the diffusion coefficients, radial distribution functions and mean square displacement of iron, and also observed the micro-structure of iron before and after oxygen injection into coolant. The present calculation shows that a significant and effective reduction of corrosion can be achieved by injection of 7.68 \times 10^{-2}-1.55 \times 10^{-1} wt\% …
The Development Of A Novel Technique To Evaluate The Cr-39 Track Response To Alpha Particles, Khalil Ibrahim Mohammad, Muzahim Ibrahim Azawe
The Development Of A Novel Technique To Evaluate The Cr-39 Track Response To Alpha Particles, Khalil Ibrahim Mohammad, Muzahim Ibrahim Azawe
Turkish Journal of Physics
A novel technique is presented for the assessment of the track response of the detector CR-39 to alpha particles by photothermal deflection spectroscopy and image analysis. The 2 new techniques can be implemented to CR-39 as in situ measurements. The proposed techniques offer the possibility of monitoring nuclear radiation directly. Photothermal deflection is described to detect the change in the thermal and optical properties of the track nuclear detector CR-39 when irradiated to alpha particles. In situ image analysis of the photothermal deflection spot is presented to assess the detection of the CR-39 of any nuclear particle or radiation instantaneously.
Numerical Experiments For Determining Laser-Induced Temperature Fields, Lyubomir Kostadinov Lazov, Nikolay Angelov Petrov
Numerical Experiments For Determining Laser-Induced Temperature Fields, Lyubomir Kostadinov Lazov, Nikolay Angelov Petrov
Turkish Journal of Physics
Based on the equation of energy balance and the equation of heat conductivity with the help of specialized software, tentative engineering calculations were performed for the process of laser marking by melting and structural changes. The functional capabilities of the software product were examined. Distribution of temperature by layers for samples of tool steel was obtained.
A Different Point Of View: A Continuous Tracing Of Acid-Base Titration With Fiber-Optic Sensor, Şerafetti̇n Yaltkaya, Esra Kendi̇r
A Different Point Of View: A Continuous Tracing Of Acid-Base Titration With Fiber-Optic Sensor, Şerafetti̇n Yaltkaya, Esra Kendi̇r
Turkish Journal of Physics
Our main aim was to investigate variations in the refractive index of a solution during chemical reaction. The variation of refractive index was measured through the entire acid--base titration process, especially near the equivalence point. To determine the equivalence point, the conductivity of the solution and the refractive index were measured simultaneously. In this preliminary study, sodium hydroxide and hydrochloric acid were used as the base and the acid solution, respectively. To measure the refractive index variation, a fiber-optic refractive index sensor was designed. The fiber-optic probe was dipped into the solution and acted as a refractive index sensor according …
Development And Utilization Of A Retarding Analyzer For Field Emission Investigation Of Lab_6/W Emitter, Ahmed Abdurrahman Ahmed Al-Tabbakh, Mahendra A. More, Dilip S. Joag
Development And Utilization Of A Retarding Analyzer For Field Emission Investigation Of Lab_6/W Emitter, Ahmed Abdurrahman Ahmed Al-Tabbakh, Mahendra A. More, Dilip S. Joag
Turkish Journal of Physics
A cold field emission from LaB_6/W-coated cathodes has been investigated with a high-accuracy and low-cost retarding field analyzer instrument. Guidelines are provided for measurements of Fowler-Nordheim (FN) characteristics and total energy distributions using a single set-up and direct detection technique to address presumed shortages in sophisticated instrumental requirements for integral investigation. Electron emission from LaB_6 nanoprotrusions, deposited on a tungsten microtip, was successfully investigated. Results emphasize a metallic behavior of the emitter in accordance with the FN theory. No size effects were observed for protrusions of 300 nm in radii.
Exact Traveling Wave Solutions Of The Perturbed Klein--Gordon Equation With Quadratic Nonlinearity In (1+1)-Dimension, Part I: Without Local Inductance And Dissipation Effect, Zai-Yun Zhang
Turkish Journal of Physics
In this paper, the auxiliary ordinary differential equation is employed to solve the perturbed Klein-Gordon equation with quadratic nonlinearity in the (1+1)-dimension without local inductance and dissipation effect. By using this method, we obtain abundant new types of exact traveling wave solutions.
Defect Studies In Strain-Relaxed Si_{1-X}Ge_X Alloys, Şeref Kalem
Defect Studies In Strain-Relaxed Si_{1-X}Ge_X Alloys, Şeref Kalem
Turkish Journal of Physics
Raman light scattering, low-temperature photoluminescence, light-scattering tomography, and hydrogenation were used to investigate optical properties of defects in strain-relaxed Si_{1-x}Ge_x (0.05 \le x \le 0.50) alloys. The photoluminescence emission was characterized by typical zero-phonon, phonon-assisted, and dislocations-related emissions, which are dependent on Ge composition x. However, luminescence spectra exhibited above band-gap features, which are likely associated with the presence of Si-rich regions in the alloys. The results are correlated with light-scattering tomography, revealing the presence of dislocations and Si precipitates. The excess peak at 519 cm^{-1} in Ge-rich samples is supportive of this observation. At low Ge content, a dislocation-related …
Recombination Mechanisms In Hydrogenated Silicon Nanocrystalline Thin Films, Zaki M. Saleh, Salam M. Kmail, Samah F. Assaf, Atif F. Qasrawi
Recombination Mechanisms In Hydrogenated Silicon Nanocrystalline Thin Films, Zaki M. Saleh, Salam M. Kmail, Samah F. Assaf, Atif F. Qasrawi
Turkish Journal of Physics
The photoconductivity dependences on temperature and illumination intensity were investigated for thin films of hydrogenated nanocrystalline silicon (nc-Si:H) grown by very-high-frequency, plasma-enhanced chemical vapor deposition. The nanocrystalline phase was achieved by heavy hydrogen dilution of silane (SiH_4). We find that the activation energy of the photoconductivity is sensitive to the incident illumination intensity for illumination intensities below 6 mW/cm^2. The photocurrent follows a power-law dependence on illumination intensity (I_{ph}\propto F^{gamma}), with gamma ranging from 0.36 to 0.83. The illumination dependence of the photocurrent suggests 2 different recombination mechanisms depending on temperature. In the lower temperature regime (300-340 K), recombination appears …
Synthesis And Optical Characterization Of Zn_{1-X}Mg_Xs: Eu Nanoparticles, Alexander Nwabueze Amah, Audu Onoja, Richard Akpagher
Synthesis And Optical Characterization Of Zn_{1-X}Mg_Xs: Eu Nanoparticles, Alexander Nwabueze Amah, Audu Onoja, Richard Akpagher
Turkish Journal of Physics
Zn_{1-x}Mg_xS: Eu^{3+} nanoparticles were synthesized by a facile co-precipitation technique with varying magnesium concentrations (0 =< x =< 0.20). X-ray diffraction results showed a mixture of cubic and hexagonal structures. There was an observed peak shift towards higher angles, decrease in peak intensities, disappearance of other peaks, and increase in diffraction peak broadening as Mg concentration increased. The estimated average particle sizes ranged from 2.0 nm to 8.79 nm. Scanning electron microscopy results showed smooth and uniform surface morphology. Energy dispersive X-ray studies indicated that the samples contained mainly Zn, S, and Eu because of the low detection limit for Mg. UV-Vis absorption spectrophotometer results showed a blue shift in energy due to quantum confinement as Mg concentration increased.
Effects Of The Different Types Of Nuclear Radiations On The Optically Stimulated Luminescence, Ayşe Güneş Tanir, Mustafa Hi̇cabi̇ Bölükdemi̇r, Tülay Neşe Kizilirmak
Effects Of The Different Types Of Nuclear Radiations On The Optically Stimulated Luminescence, Ayşe Güneş Tanir, Mustafa Hi̇cabi̇ Bölükdemi̇r, Tülay Neşe Kizilirmak
Turkish Journal of Physics
This study aims to investigate the effects of different nuclear radiation fields on an optically stimulated luminescence (OSL) dosimeter using Al_2O_3:C material. The Al_2O_3:C material was exposed to alpha- and beta-particles and gamma-photons, and the luminescence signals were measured by stimulation with a blue light emitting diode. It is concluded that the OSL technique is suitable for obtaining an adequate blue light stimulated luminescence signal in alpha, beta, and gamma radiation fields, and if the source activity was low, the statistical distributions were large.
Level Structure Of ^{210}Po By Means Of Surface Delta Interaction, Ali Khalaf Hasan, Abdul Ridha Hussain Subber
Level Structure Of ^{210}Po By Means Of Surface Delta Interaction, Ali Khalaf Hasan, Abdul Ridha Hussain Subber
Turkish Journal of Physics
Within the framework of the shell model, we consider the residual interaction to be a surface delta interaction. This interaction has been applied in the calculation of the energy levels of ^{210}Po, which belong to N = 126 magic closed shell nuclei. The pure and the configuration mixings are applied in the calculations of matrix elements. The predicted energy levels are compared with experimental data.