Digital Commons Network^™

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 …

Optimization Of Laser Marking With The Help Of Simulation Models, Lyubomir Kostadimov Lazov, Nikolay Angelov Petrov

Turkish Journal of Physics

This article covers the results of several numerical experiments carried out with specific software working under MATLAB for marking of tool steel and electronic elements. CuBr and Nd:YAG lasers were used in this study. Simulations with 3 different durations of pulse of laser radiation were achieved. Numerical calculations were performed with values (for laser sources and technological parameters) based on real experiments.

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)

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 …

Kantowski-Sachs Cosmological Model With Wet Dark Fluid In The General Theory Of Relativity, Arun Ravishankar, Bivudutta Mishra, Pradyumn Kumar Sahoo

Turkish Journal of Physics

The purpose of this study was to investigate the role of wet dark fluid (WDF) in Kantowski-Sachs space-time in the general theory of relativity. In this theory, we solved the field equations for the case where \rho _{WDF}=-2p_{WDF}. Various physical and geometrical properties of the model are also discussed.

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.

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 …

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 …

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

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.

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 …

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

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.

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

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 …

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.

Effect Of Microwave Sintering On Grain Size And Dielectric Properties Of Barium Titanate, Praveena Kuruva, Uma Maheshwara Singh Rajaputra, Srinath Sanyadanam, Ramana Murthy Sarabu

Turkish Journal of Physics

In the present paper, nanosized barium titanate (BaTiO_3) powders were synthesized by microwave hydrothermal method. The structural characterization of as-prepared powders was investigated using X-ray diffraction and Fourier transform infrared spectroscopy. The particle size was estimated using a transmission electron microscope. The nanopowders were sintered at different temperatures using a microwave furnace, followed by characterizations such as X-ray diffraction and field emission scanning electron microscopy. The dielectric constant behavior was observed as a function of frequency (100 Hz to 1 MHz) and temperature. The ferroelectric nature was confirmed from polarization-electric field loops.

Vacuum Properties Of Tarla, Hüsnü Aksakal, Ertan Arikan, Zafer Nergi̇z

Turkish Journal of Physics

The Turkish Accelerator and Radiation Laboratory at Ankara (TARLA) is a part of the Turkish Accelerator Center project, which was designed to produce an infrared free electron laser in the wavelength band of 2-250 mu m. The beamline of TARLA consists of 4 major sections: injector, beam transport line with linacs, optical cavities, and dump. All system components must be kept under ultrahigh vacuum standards to prevent beam scattering with residual gas. In the present study, the vacuum requirements of the beamline are defined and simulation vacuum and gas flow in the accelerator are presented.

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.

Identification Of Spontaneous Fission Fragments By Using Thermally Annealed Padc Films, Abdallah F. Saad, Nama Abdelssadk Hamed, Yasin Kailani Abdalla

Turkish Journal of Physics

One of main requirements in applied nuclear physics is the need of a detector capable of detecting and differentiating different particles. Thus, the fission products from a ^{252}Cf radioactive source, after about 12 half-life periods of alpha decay, are registered using virgin and annealed CR-39 polyallyldiglycol carbonate (PADC) films. In the case of virgin CR-39, a single peak appears corresponding to the heavy group of these products, while the other peak related to the light group is obscured. The annealed CR-39 detectors, on the other hand, were demonstrated to be highly sensitive to the fission fragments, and as a result …

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.

Magnetic Wiggler-Assisted Third-Harmonic Generation Of A Gaussian Laser Pulse In Plasma, Hirdesh Sharma, Harsha Jaloree, Jetendra Parashar

Turkish Journal of Physics

A Gaussian laser pulse propagating through plasma in the presence of a magnetic wiggler produces third-harmonic radiation. The wiggler's magnetic field provides additional momentum required for phase matching. The required wiggler wave number is sensitive to pulse duration and amplitude. The efficiency of the process is significant at the instant at which the phase matching condition is satisfied.

Exact Solution Of Frw Perfect Fluid Model Interacting With Zero-Rest-Mass Scalar Field And Electromagnetic Field In B-D Theory, Kangujam Priyokumar Singh, Chungkham Gokulchandra Singh

Turkish Journal of Physics

Considering a spherically symmetric nonstatic cosmological flat model of the Robertson-Walker universe, the problem of perfect fluid distribution interacting with the gravitational field in the presence of a zero-rest-mass scalar field and electromagnetic field in Brans-Dicke (B-D) theory has been investigated. Exact solutions are obtained by using a general approach of solving the partial differential equations and it has been observed that the electromagnetic field cannot survive the cosmological flat model due to the action caused by the presence of the zero-rest-mass scalar field, and the isotropic pressure p turns out to be negative. The pressure and density are found …

Quasi-Exact Thermodynamic Properties Of A Relativistic Spin-Zero System Under Cornell And Generalized Morse Potentials, Bentol Hoda Yazarloo, Hassan Hassanabadi, Saber Zarrinkamar

Turkish Journal of Physics

The thermodynamic properties of a relativistic spin-zero system are investigated via the Klein-Gordon equation under the Cornell and generalized Morse potentials. In particular, the partition function and mean and free energies are calculated and their behavior versus variations of the potential coefficients is presented.

Automatic Detection Of Polypoid Skin Lesions: The Squash Sign, Saurabh G. Karnik

Masters Theses

“Earlier detection of malignant melanoma can save lives. Automatic in-vivo methods of melanoma detection including smart-phone applications are now available, but specificity is low, i.e. too many benign lesions are detected as possible melanomas. Polypoids, elevated and rounded lesions are one class of benign lesions. These raised lesions with piecewise circular borders, predominantly intradermal nevi and cutaneous polyps (IDNs), are always benign. Variegated coloring present in polypoid lesions can lead physicians to perform an unneeded biopsy. Contact dermatoscope plates with gel squash these lesions, leaving a “squash sign” marker of benignancy which can be automatically detected. We present a method …

Significance And Analysis Of Milia-Like Cysts In Dermoscopy Skin Lesion Images, Sneha K. Mahajan

Masters Theses

“Milia-like cysts (MLCs) are dermoscopic structures frequently observed in seborrheic keratoses(SKs), which are the most common type of skin lesions. Diverse appearances of these skin lesions make them difficult to differentiate from melanoma, a deadly type of skin cancer. Classified by size into two main groups, starry MLCs and cloudy MLCs, the presence of these structures in a skin lesion has been known to help differentiate benign lesions from melanoma. Though the presence of cloudy MLCs is not exclusively associated with SKs, they can be a useful tool to differentiate SKs from melanoma. This research study determines the statistical occurrence …

Representing Social Enterprise, Alicia E. Plerhoples

Georgetown Law Faculty Publications and Other Works

This article explores the representation of social enterprises—i.e., nonprofit and for-profit organizations whose managersstrategically and purposefully work to create social, environmental, and economic value or achieve a social good through the use of business techniques—in the Social Enterprise & Nonprofit Law Clinic at Georgetown University Law Center. Representation of social enterprises helps create a dynamic curriculum through which law students learn to merge corporate legal theory with transactional law practice. Through service to social enterprises, law students (i) learn about corporate governance and corporate legal theory as well as business models and mechanisms that support social and environmental value creation …

Narratives Of The European Crisis And The Future Of (Social) Europe, Philomila Tsoukala

Georgetown Law Faculty Publications and Other Works

This article examines two distinct types of narratives prevalent in academic writing and popular press regarding the causes of the crisis in Europe. The first type, a morality tale, attributes the crisis to profligate southern states that refused to abide by the strictures of the Stability and Growth Pact. The second type is focused on the structural reasons for the crisis, emphasizing the nature of the European Union as a non-optimal currency area, and the euro as a factor in the creation of trade imbalances and competitiveness problems within the euro zone. Each type of narrative suggests a different type …

A Conforming Method For Regional Marginal Loss Surplus Allocation, Xiaolong Wang

Masters Theses

"The marginal transmission loss model is used in electricity markets across the United States to measure a resource's marginal contribution to system loss. This model prices loss into the locational marginal price as a marginal loss component. Marginal loss pricing will render a net revenue surplus within an energy balanced system. This marginal loss surplus (MLS) is typically allocated back to scheduling coordinators in proportion to the measured demand on a system-wide basis. However, when the system experiences heterogeneous loss across different regions, the system-wide allocation method fails to recognize the regional differences in actual loss costs. As a result, …

Dynamic Mechanical Analysis And Computer Simulation Of Polyurea Aerogels, Victoria Ann Prokopf

Masters Theses

"Historically, the use of aerogels has been limited due to their poor mechanical properties. However, polyurea aerogels have proven to be mechanically strong under quasi-static conditions. Polyurea aerogels can be created by filling molds of the desired shape with a liquid solution that then creates a solid gel filled with liquid. The liquid can be removed from the gel by supercritical drying. This thesis outlines dynamic testing as well as simulation for polyurea aerogels.

Testing has been conducted in dynamic tension and bending for densities of polyurea aerogels ranging from 0.12 g/cm³ to 0.31 g/cm³. In most …