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2018

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Articles 151 - 173 of 173

Full-Text Articles in Physical Sciences and Mathematics

Symmetry Reduction Of The First Heavenly Equation And $2+1$-Dimensional Bi-Hamiltonian System, Devri̇m Yazici Jan 2018

Symmetry Reduction Of The First Heavenly Equation And $2+1$-Dimensional Bi-Hamiltonian System, Devri̇m Yazici

Turkish Journal of Physics

The first heavenly equation of Plebanski in the two-component form is known to be a $3+1$-dimensional tri-Hamiltonian system. We show that a particular choice of symmetry reduction applied to the first heavenly equation yields a $2+1$-dimensional bi-Hamiltonian system. For this tri-dimensional system, we present Lagrangian, Hamiltonian, and recursion operators; point symmetries; and integrals of motions.

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Lattice Calculations For Two-Component Fermion Systems With Unequal Masses: Onedimension, Serdar Elhatisari Jan 2018

Lattice Calculations For Two-Component Fermion Systems With Unequal Masses: Onedimension, Serdar Elhatisari

Turkish Journal of Physics

We consider systems of two-component fermions with unequal masses and interacting via a short-range attractive potential. We discuss the case where the two-component fermions form a shallow dimer with large scattering length. The three-fermion and four-fermion systems with such properties are universal and characterized by the twofermion scattering length aff and the ratio of the mass of spin-↑ fermion to the mass of spin-↓ fermion, m↑/m↓. In this study, using lattice effective field theory, we analyze fermion-dimer and dimer-dimer systems and calculate the universal fermion-dimer and dimer-dimer scattering lengths for various values of the mass ratio m↑/m↓. We find that …

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Surface Effect In Explaining The Elastic Scattering Of The $\Alpha +^{12}$C System At Low Energies, Yasemi̇n Küçük Jan 2018

Surface Effect In Explaining The Elastic Scattering Of The $\Alpha +^{12}$C System At Low Energies, Yasemi̇n Küçük

Turkish Journal of Physics

In this paper, the elastic scattering angular distributions data of the $\alpha +$12C reaction at an energy range of 13.0 to 172.5 MeV were analyzed within the framework of optical model formalism. A phenomenological deep real potential was used with a phenomenological Woods-Saxon type imaginary potential. Excellent agreement was obtained in the high-energy region. The phenomenological deep potential was unable to explain the experimental data in the low-energy region. The experimental data at both low and high energies could not be explained at the same time. In order to explain the data simultaneously at low energy and high energy, the …

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High Density Equation Of State And Condensation Of Ideal Bose Gas Using Mayer'sgenerating Function, Suresh Thelakkadan Puthiyaveettil, Udayanandan Kandoth Murkoth Jan 2018

High Density Equation Of State And Condensation Of Ideal Bose Gas Using Mayer'sgenerating Function, Suresh Thelakkadan Puthiyaveettil, Udayanandan Kandoth Murkoth

Turkish Journal of Physics

The equation of state of an ideal collection of bosons in the low-density and high-density regime are found using the method of cluster expansion with Mayer's generating function. The saturation density and the other thermodynamic properties are calculated by the application of Mayer's convergence of the partition function. By calculating the value of saturation density from the singularity of the partition function series, the differences between the Mayer series convergence and the virial series convergence for ideal bosons are also established.

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Modeling Of A Sessile Droplet With The Curvature Dependence Of Surface Tension, Sergo Rekhviashvili, Aslan Sokurov Jan 2018

Modeling Of A Sessile Droplet With The Curvature Dependence Of Surface Tension, Sergo Rekhviashvili, Aslan Sokurov

Turkish Journal of Physics

In this paper, using the Gibbs dividing surface method, the formula that determines the curvature-dependent surface tension in a system with two phases is deduced. The well-known Tolman formula is a special case for this formula. The problem of a sessile droplet is considered. The Bashforth-Adams equation analogue in view of the curvaturedependent surface tension is obtained and the numerical solution of the equation is carried out. We show that if the droplet size is not so large compared to the thickness of the surface layer (micro- or nanodroplets), the dependence of the surface tension on the curvature is very …

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Multiple-Line Study Of Molecular Gas In Spiral Galaxy Ngc 2903, Selçuk Topal Jan 2018

Multiple-Line Study Of Molecular Gas In Spiral Galaxy Ngc 2903, Selçuk Topal

Turkish Journal of Physics

Multiple molecular lines with radiative transfer modeling are a powerful tool to probe the physics of starforming gas in galaxies. We investigate the gas properties in the center of spiral galaxy NGC 2903 using low-J CO lines, i.e. 12CO(1-0), 12CO(2-1), 12CO(3-2), 13CO(1-0), and HCN(1-0). We apply a nonlocal thermodynamic equilibrium radiative transfer code to derive beam-averaged molecular gas properties. We use two methods (i.e. X2 minimization and likelihood) to define the best model representing the observed line ratios best. The line ratio diagnostics suggest that CO gas in the center of NGC 2903 is thinner and the dense gas fraction …

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On Oxygen-Rich Sr Variables In The Solar Neighborhood, Tuncay Özdemi̇r Jan 2018

On Oxygen-Rich Sr Variables In The Solar Neighborhood, Tuncay Özdemi̇r

Turkish Journal of Physics

Brightness distribution of variable stars was investigated based on good Hipparcos parallaxes of semiregular variables (SRVs) in the solar neighborhood, and it is shown that the order of the variability types Lb, SR, SRb, SRa, and Mira is, statistically, an order of increasing brightness along the red giant branch and asymptotic giant branch. In addition, it is also shown that the majority of Miras are above and majority of SRVs are below the tip of the red giant branch. The periods of SRVs that fall in Wood's sequence C (fundamental mode) of large Magellanic clouds were identified. Statistically, the order …

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Lattice Modeling Of A Real Gas Revisited, Lisha Damodaran, Udayanandan Kandoth Murkoth Jan 2018

Lattice Modeling Of A Real Gas Revisited, Lisha Damodaran, Udayanandan Kandoth Murkoth

Turkish Journal of Physics

The spin-half Ising model has been used with remarkable success in describing magnetism and phase transition in magnetic materials. Likewise, the lattice gas model, which uses the spin-1 Ising model, was employed to investigate the phase transition in liquid-gas systems. In all the earlier lattice gas models, the kinetic energy of atoms occupying the various lattice sites were not considered for finding the equation of state. In this paper we use the Hamiltonian with kinetic energy and a modified equation of state is obtained. The isotherms of this model show the behavior of real gases at all pressures and they …

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Annealing Effect Of Gold Thin Films On The Light Output Performances Of Organic Light Emitting Diodes, Seli̇n Piravadili Mucur, Emi̇ne Teki̇n Jan 2018

Annealing Effect Of Gold Thin Films On The Light Output Performances Of Organic Light Emitting Diodes, Seli̇n Piravadili Mucur, Emi̇ne Teki̇n

Turkish Journal of Physics

Gold thin films (GTFs) are transferred onto a nanostructured surface and their effects on the characteristics of organic light emitting diodes (OLED) are investigated. GTF deposition is realized by the physical vapor deposition technique under high vacuum. Globose gold nanostructures are successfully generated by annealing GTFs at different temperatures. Atomic force microscopy reveals morphological changes affected by film thicknesses and annealing temperatures. In the tailored device architecture, GTFs, [poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene are used as a hole injection layer, a hole transport layer, and an emissive layer, respectively. The performances of the fabricated OLEDs are enhanced in the presence …

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Field Electron Emission Area Revisited: An Integrated Method For The Area Extraction Model, Ahmed Abdulrahman Al-Tabbakh Jan 2018

Field Electron Emission Area Revisited: An Integrated Method For The Area Extraction Model, Ahmed Abdulrahman Al-Tabbakh

Turkish Journal of Physics

For electron field emitters, the emitter's physical and geometrical parameters, namely the emitter work function and its geometrical factor, are extracted from the slope of the Fowler-Nordheim (FN) plot. The literature contains few investigations and reviews of extended parameter extraction models based on the slope and intercept of the FN plot. However, due to the complexity of these reviews, there is a great need for an integrated approach to the area extraction model whereby a simplified account of the derivation and implementation of the model is presented and made convenient, especially for scholars other than physicists and engineers. This is …

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Characterizing Decaying Dark Matter: X-Ray Emission From Sterile Neutrinos, Murat Hüdaverdi̇ Jan 2018

Characterizing Decaying Dark Matter: X-Ray Emission From Sterile Neutrinos, Murat Hüdaverdi̇

Turkish Journal of Physics

Recently, an unknown emission line at E $\sim$3.5 keV from several astrophysical objects has been detected. The line is suggested to be originating from decaying dark matter particles. The results have drawn great attention from the astrophysics and particle physics community. Since the detected line is significantly weak there has also been a long debate over the origin of this mysterious signal. The most accepted scenario is a radiatively decaying sterile neutrino of 7.1 keV in mass producing a monochromatic 3.5 keV line, which is observable in X-ray energy ranges. The problem has not been settled and further observations from …

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Investigation Of The Influence Of Various Reflector Elements Material Types On The Core Nuclear Parameters Of The 2 Mw Triga Mark-Ii Research Reactor Using The Monte Carlo Code, Abdelaziz Darif, Abdelouahed Chetaine, Mohammed Mghar, Ouadie Kabach Jan 2018

Investigation Of The Influence Of Various Reflector Elements Material Types On The Core Nuclear Parameters Of The 2 Mw Triga Mark-Ii Research Reactor Using The Monte Carlo Code, Abdelaziz Darif, Abdelouahed Chetaine, Mohammed Mghar, Ouadie Kabach

Turkish Journal of Physics

The influence of variation in the kind of material of neutron reflector elements on the core neutronic parameters of the Moroccan Triga Mark-II research reactor was examined. The comparison was made between three kinds of reflector element materials: graphite, beryllium, and beryllium oxide. MCNP5 Monte Carlo computations of the effective neutron multiplication factor (${k}_{{eff}})$ of the reactor according to the number of reflector material elements inserted in the reactor core for these three reflector elements materials families were carried out. The results found could be used in order to increase the ${k}_{{eff}}$ parameter without changing the size of the reactor.

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Quark Gluon Plasma And Upsilon Suppression, Rismita Ghosh, Aparajita Bhattacharya, Ballari Chakrabarti Jan 2018

Quark Gluon Plasma And Upsilon Suppression, Rismita Ghosh, Aparajita Bhattacharya, Ballari Chakrabarti

Turkish Journal of Physics

The time-dependent suppression probability P(t) of upsilon particles has been estimated due to the screening when embedded in the medium of quark gluon plasma where the screened potential is represented by an optical potential of type $V(r,\lambda) = - [\frac{V_{0}+iW_{0}}{1+exp((r-R)\lambda)}]$. A similar type of variation of suppression probability has been obtained by others. It has been observed that $t_{\frac{1}{2}}$ for melting of $\Upsilon$ is $\sim$ 1.5 fm/c. The variation of the screening radii of heavy mesons $(J/\psi, \Upsilon)$ for 1S and 2S states with respect to plasma radius have also been investigated with the same complex screening potential. We have …

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Bessel And Bessel Vortex Beams Generated By Blunt-Tip Axicon, Ramazan Şahi̇n Jan 2018

Bessel And Bessel Vortex Beams Generated By Blunt-Tip Axicon, Ramazan Şahi̇n

Turkish Journal of Physics

A theoretical prediction of the propagation characteristics of Laguerre--Gaussian beams after passing through a blunt-tip axicon is presented. An ideal axicon generates theoretically perfect diffraction-free and smooth-on-axis intensity Bessel beams, while experiments and calculations show that a zeroth-order Bessel beam deviates from its perfect behavior. Strong intensity modulation occurs due to interference around the center of the beam. The origin of these oscillations should be explored to increase the quality of beam shaping. This research shows that these oscillations can be reduced by stopping the beam center for a small portion or by optimizing input beam parameters. On the other …

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A Note On Noncompact And Nonmetricit Quadratic Curvature Gravity Theories, Suat Dengi̇z Jan 2018

A Note On Noncompact And Nonmetricit Quadratic Curvature Gravity Theories, Suat Dengi̇z

Turkish Journal of Physics

In this note, we evaluate the Weyl-invariant quadratic curvature tensors for the particular Weyl gauge field constructed in the $3+1$-dimensional noncompact Weyl-Einstein-Yang-Mills model. We subsequently extend the model to its higher curvature version. We also compute the Weyl-invariant extension of the topological Gauss-Bonnet term for this specific choice of vector field.

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Predictions On Three-Particle Azimuthal Correlations In Proton-Proton Collisions, Şener Özönder Jan 2018

Predictions On Three-Particle Azimuthal Correlations In Proton-Proton Collisions, Şener Özönder

Turkish Journal of Physics

The ridge signal, which is long-ranged in rapidity, in di-hadron correlations in high-multiplicity p-p and p-A collisions opened up a whole new research area in high-energy QCD. Although the ridge had been observed in A-A collisions and interpreted as a result of the radial flow of quark-gluon plasma, it had not appeared until recently in the data of small collision systems such as p-p and p-A, nor had it been predicted theoretically or seen in event generators. There are two competing approaches that attempt to explain the systematics of the di-hadron ridge signal: hydrodynamics and gluon saturation physics (color glass …

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Stephen Hawking - A Great Mind (8 January 1942 -- 14 March 2018), Mukhtar Ahmed Rana Jan 2018

Stephen Hawking - A Great Mind (8 January 1942 -- 14 March 2018), Mukhtar Ahmed Rana

Turkish Journal of Physics

Hawking induced a knowledge revolution in theoretical physics. His bedrock concepts and explanations reshaped modern physics.

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Nature Of Entropy In A Scalar-Tensor Theory Of Gravity, Onur Siğinç, Mustafa Salti, Hi̇lmi̇ Yanar, Oktay Aydoğdu Jan 2018

Nature Of Entropy In A Scalar-Tensor Theory Of Gravity, Onur Siğinç, Mustafa Salti, Hi̇lmi̇ Yanar, Oktay Aydoğdu

Turkish Journal of Physics

This work is devoted to studying the generalized nature of the entropy function in a specific form of the scalar-tensor-vector (STeVe) theory of gravity for the Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetime in the state of thermal equilibrium. For this purpose, we define an equilibrium picture of thermodynamics by making use of a suitable set of the dark energy density and dark pressure descriptions, which defines an energy-momentum tensor obeying the local energy conservation law. Furthermore, we also discuss our results numerically in order to get additional implications.

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Isotopic Distribution In Projectile Fragments Above The Coulomb Barrier, Ayşegül Kaya, Ni̇hal Büyükçi̇zmeci̇, Riza Oğul Jan 2018

Isotopic Distribution In Projectile Fragments Above The Coulomb Barrier, Ayşegül Kaya, Ni̇hal Büyükçi̇zmeci̇, Riza Oğul

Turkish Journal of Physics

We have studied fragmentation properties of projectiles in peripheral heavy-ion collisions within a statistical ensemble approach. Distributions of projectile fragments are calculated for the reaction systems 86Kr on 58;64Ni and are compared to the experimental data for the same reactions at projectile energy of 15 MeV/nucleon. We assume that the projectile nuclei capture many neutrons from the targets as a result of the multinucleon transfer reactions (direct and fast reactions) at the first step of the dynamical stage of the collisions, and then the excited spectators are formed during the preequilibrium process (multistep reactions) long before the statistical equilibrium stage, …

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The Field Blocking On The Interface With Nonlinear Response Between Nonlinearfocusing Media, Sergey Savotchenko Jan 2018

The Field Blocking On The Interface With Nonlinear Response Between Nonlinearfocusing Media, Sergey Savotchenko

Turkish Journal of Physics

We consider the nonlinear nonsymmetrical spatially distributed excitations near the thin layer with nonlinear properties separated with two media with Kerr-type focusing (positive) nonlinearity. We use the nonlinear Schrödinger equation with nonlinear potential containing two parameters to describe the new types of nonlinear stationary states. The problem is reduced to the solution of nonlinear Schrödinger equations on half spaces with the nonlinear boundary conditions at the interface plane. We obtain and analyze the two types of nonlinear excitations describing the effect of the field blocking passing through the interface into one half-space from another one. The field blocking effect is …

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A Phenomenological Calculation For W+W- Diboson Production For The Largehadron Collider And Future Circular Collider, Kamuran Di̇lsi̇z, Hasan Oğul Jan 2018

A Phenomenological Calculation For W+W- Diboson Production For The Largehadron Collider And Future Circular Collider, Kamuran Di̇lsi̇z, Hasan Oğul

Turkish Journal of Physics

The Large Hadron Collider (LHC) at CERN has been designed to collide beams of protons at 7, 8, 13, and 14 TeV center-of-mass energies and a new hadron collider called the Future Circular Collider (FCC), which is larger and more energetic than the LHC, is being planned for the near future. The maximum planned energy for FCC is 100 TeV center-of-mass energy. In this regard, we present the leading order and next-to-leading order cross-section predictions of two simultaneously produced opposite-sign W bosons at 7, 8, 13, 14, and 100 TeV center-of-mass energies by using the MCFM MC generator. The results …

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Effect Of Al And Ga Codoping On The Morphological, Electronic, And Opticalproperties Of Zno Transparent Conductive Thin Films Prepared By Spray Pyrolysistechnique, Worapot Sripianem, Ratchatee Techapiesancharoenkij Jan 2018

Effect Of Al And Ga Codoping On The Morphological, Electronic, And Opticalproperties Of Zno Transparent Conductive Thin Films Prepared By Spray Pyrolysistechnique, Worapot Sripianem, Ratchatee Techapiesancharoenkij

Turkish Journal of Physics

Codoping a semiconductor thin film with two or more dopants is a feasible technique to improve the electrical properties of the thin film. In this work, we studied the codoping of Al and Ga n-type impurities in a ZnO film (AGZO) deposited on a glass substrate by the spray pyrolysis method. The total doping concentration, [Al + Ga]/[Al + Ga + Zn], was 5 at.% with varying Al:Ga codoping proportions of 0:5, 1.25:3.75, 2.5:2.5, 3.75:1.25, and 5:0 at.%. The effect of Al/Ga codoping on the structural, texture, morphological, optical, and electrical properties of the AGZO films were investigated using X-ray …

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One-Dimensional Fluid And Hybrid Numerical Analysis Of The Plasma Properties Inthe Discharge Channel Of A Hall Thruster, Çinar Yüncüler, İsmai̇l Rafatov, Demet Uluşen Aksoy Jan 2018

One-Dimensional Fluid And Hybrid Numerical Analysis Of The Plasma Properties Inthe Discharge Channel Of A Hall Thruster, Çinar Yüncüler, İsmai̇l Rafatov, Demet Uluşen Aksoy

Turkish Journal of Physics

One-dimensional fluid and hybrid fluid-kinetic numerical codes are developed and applied to the analysis of axial distributions of plasma properties in the discharge channel of a Hall-effect thruster. Within the hybrid model ions are described by the kinetic Vlasov equation, while electrons and neutral atoms are treated as fluids. The results obtained from fluid and hybrid models are compared. Different operating regimes such as damped, periodic, and aperiodic irregular oscillations about the stationary state are observed and discussed. Thrust and efficiency of the thruster for different input parameters are estimated.

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