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Electrical Switching In Potassium-Boro-Vanadate-Iron Glasses, H. R. Panchal, D. K. Kanchan

Turkish Journal of Physics

Electrical switching has been observed in 20K_2O : (75-y)V_2O_5 : yB_2O_3 : 5Fe_2O_3 glasses which were prepared by a splat quenching method. To investigate switching phenomenon, glass samples of the same dimension from as quenched material were examined for their I-V characteristics at various ambient temperatures. The exponential decrease of switching voltage is observed with increasing ambient temperature indicating the cause of switching due to Joule's heating. It is also observed that the switching voltage can be controlled by varying the ambient temperature and switching temperature by changing the voltage. The dependence of switching temperature on the amount of V_2O_5 …

Effect Of Ionizing Radiation On The Silicon Impatt Diode Characteristics, M. B. Tagaev

Turkish Journal of Physics

We investigated the effect of ^{60}Co \gamma-irradiation (doses from 10^2 to 2 \times 10^6 Gy), both without and with heat annealing, on silicon IMPATT diode parameters. It is shown that such treatments improve the diode characteristics (particularly decrease the reverse current and increase both the output and the diffusion length of the minority charge carriers) due to radiation-enhanced processes.

The Peculiarities Of The Electrical And Thermoelectrical Properties Of P-Type Ag_2te, Ali̇ İhsan Demi̇rel, S. A. Aliev, F. F. Aliev, F. Z. Guseynov, Sali̇m Orak

Turkish Journal of Physics

The electrical and thermoelectrical properties of p-type Ag_2Te have been investigated. Various peculiarities were observed: the minimum (at T \approx 65 K) and maximum (at T \approx 200 K) on the temperature dependence of conductivity \sigma (T); the weak dependence of Hall coefficient R(T) (in 200-300 K range) and the maximum (at T \approx 100 K and 250 K) on the temperature dependence of thermal power \alpha_0 (T). The investigation results were interpreted by two-bands model. It is shown that mentioned peculiarities have been stimulated by the narrow gap of Ag_2Te and its temperature dependence.

Relative L X-Ray Fluorescene Cross-Sections In Heavy Elements In The Energy Region Of 16-122 Kev, Oğuz Doğan, Mehmet Ertuğrul, Önder Şi̇mşek, Ümi̇t Turgut, Hasan Erdoğan

Turkish Journal of Physics

Relative L1, L\alpha, L\beta and L\gamma x-ray fluorescence cross-sections were observed in Ta, W, Re, Au, Hg, T1, Pb, Bi, Th and U of 16.03, 17.78, 22.58, 25.77, 32.89, 38.18, 43.94, 50.21, 59,5 and 122 keV energies. In this study, L X-ray fluorescence cross-sections were measured at 59.5 and 122 keV and measured values of the other energies were taken from tables by Mann et. al. (1). The experimental relative fluorescene cross-sections were computed for the excitation energies 16.03, 17.78, 22.58, 25.77, 32.89, 38.18, 43.94, 50.21, 59.5 and 122 keV, compared with the theoretically calculated values by Scofield(11). The experimental …

Supersymmetric Electroweak Radiative Corrections To E^+ E^- -> W^+W^-, S. Alam

Turkish Journal of Physics

In this short note we summarize some of the work of our thesis, which is also reported elsewhere in detail. We have examined the one loop quantum corrections to the W pair production in the electron positron annihilation in the context of supersymmetric electroweak theory. We have adopted the On Mass Shell Renormalization scheme of Sakakibara and previously demonstrated the consistency of this scheme. The relevant analytic results are written out. A complete computer program for these corrections has been developed. This program has been checked in several ways to ensure against errors over the life of the calculation where …

Effect Of Illumination Temperature On Thermally Stimulated Current Spectrum Of Tlins_2, Selahatti̇n Özdemi̇r, Rauf Süleymanov, Mahmut Bucurgat, Enver Bulur

Turkish Journal of Physics

The effect of pre-illumination on both thermally stimulated current and photocurrent spectra of TlInS_2 crystal is investigated. The increase in the photosensitivity of the crystal by several orders of magnitude together with the appearance of a new peak in the thermally stimulated current spectrum are observed as a result of the pre-illumination process. The filling of the traps, especially the sensitizing centers, during the pre-illumination is found to be the most favourable physical mechanism to explain the results.

Confined Bipolarons In The Strong Coupling Limit, R. Tuğrul Senger, Ati̇lla Erçelebi̇

Turkish Journal of Physics

Within the framework of the strong-coupling polaron theory and the bulk phonon approximation we report the possibility and criteria in achieving stable bipolaron states in confined media. We use a simple model of two electrons constrained within an anisotropic three dimensional parabolic potential box of tunable barrier slopes. Conforming the confining potential from one geometry to the other, we obtain an explicit tracking of the stability criteria as a function of the degree of confinement uncovering all low dimensional major geometric configurations of common interest.

Implications Of \Delta\Rho And Charm Ii Data For Z' Physics, Durmuş Ali̇ Demi̇r

Turkish Journal of Physics

We discuss the constraints on the Z^{\prime} model parameters coming from Z-pole and low-energy \nu_{\mu}-e scattering data in the frame work of GUT-motivated models. We find that when the coupling constant of the extra U(1) is small (large) the parameter space is mainly determined by the Z-pole (the low-energy \nu_{\mu}-e scattering) data.

Electroweak Symmetry Breaking In Low-Scale Quantum Gravity, M. Boz, A. Demi̇r, Namik Kemal Pak

Turkish Journal of Physics

We discuss the implications of low-scale quantum gravity on electroweak symmetry breaking by computing one-loop gravitational corrections to the Higgs potential. We conclude that these radiative corrections are quite large after summing over the graviton and dilaton Kaluza-Klein towers, and there is no possibility of electroweak symmetry breaking unless one allows for the complex vacuum expectation value for the Higgs field.

Projectile Fragmentation In Emulsion At (4.1-4.5) A Gev/C, A. El-Naghy, S. A. H. Abou-Steit, M. Mohery

Turkish Journal of Physics

The fragmentation process has been investigated for 4.5A GeV/c^{28}Si nuclei in emulsion and compared with the results of 4.5A GeV/c^{24}Mg and 4.1A GeV/c^{22}Ne in order to test the validity of the different theoretical models. It has been found that a single parameter distribution is insufficient to explain exactly the fragmentation process. Correlation studies have shown to be necessary for distinguishing between the different theoretical models for the fragmentation. The impact parameter, which defines the nature of the collision, has been found to influence considerably the shape of the charge yield distribution. The angular distributions of the projectile fragments can be …

Electrodynamics With Toroid Polarization, V. M. Dubovik, B. H. Saha

Turkish Journal of Physics

A modified system of equations of electrodynamics of continuous media has been obtained. Beside the Lagrangian system an alternative gauge-like formalism has been developed to introduce the toroid moment contributions in the obtained equations. The two potential formalism that was worked out by us earlier has been developed further where along with the two vector potentials we introduce two scalar potentials thus taking into account all four basic equations of electromagnetism.

Stellar Observations Made At The Malatya Danjon Astrolabe Station, Orhan Gölbaşi, Hüseyi̇n Kiliç, Fernand Chollet

Turkish Journal of Physics

We give here the first results of astrometric stellar observations made at the Malatya Station with the modified astrolabe of Paris observatory. This campaign is conducted as part of a cooperation between Inönü University and the Paris Observatory. The astrolabe, which is strictly similar to that of Santiago de Chile, can use two reflecting prisms instead of the trnsparent prism of the Danjon Astrolabe. Consequently, it is possible to observe at the two zenith distances of 30° and 60°. The time is supplied by a GPS receiver which gives UTC with the necessary precision. As the station is a new …

Canonical Treatment Of Regular Lagrangians With Holonomic Constraints As Singular Systems, Eqab M. Rabei

Turkish Journal of Physics

Regular Lagrangians with holomonic constraints are treated as singular systems using the canonical method. The Lagrange multipliers are introduced as generalized coordinates. The regular Lagrangians are extended to be singular and the Hamiltonian formulation is obtained. The equations of motion are written as total differential equations in terms of the time t and the Lagrange multipliers. It is also shown that Lagrange multipliers can be determined from the integrability conditions.

Magnetisation In Two-Dimensions, Bengü Kaplan

Turkish Journal of Physics

We discuss the magnetisation deviation in two-dimensions (2d) for an iron film for which the anisotropy is much smaller and hence the magnetisation is a stronger function of temperature. The magnetisation deviation can be adequately described by an RPA (random phase approximation) approach. Our results fit the experimental data at high fields and hence can be used to estimate the value of the effective exchange interaction (J_{2d}) for monolayer (ML) films.

A Magnetization And Gmr Study On Multilayered Fe/Ag/Co Thin Film, Cengi̇z Bi̇rli̇kseven, Alpan Bek, Hüseyi̇n Zafer Durusoy

Turkish Journal of Physics

Single layer Fe(20Å) and Co(20Å) and multilayered Ag(20Å)/[Fe(20Å)/Ag(40Å)/Co(20Å)/Ag (40Å)] x 3/Ag(20Å) films were prepared in UHV by magnetron sputtering technique onto the silicon substates. Films were determined to have polycrystalline nature through SEM examination. Magnetization measurements were made on single and multilayer films. Due to the polycrystalline structure of the films, rounded magnetization curves were obtained. The GMR effect showed a rounded behaviour which also is an indication of the polycrystallinity of the films. The GMR effect, measured in Fe/Ag/Co multilayer structure, was analyzed with the help of magnetization behaviour of the multilayer structure and magnetization behaviour of the single …

Low-Magnetic Field Microwave Absorption In Superconductors And Conducting Polymers, I. L. Khairullin, P. K. Khabibullaev, V. Yu. Sokolov, A. A. Zakhidov

Turkish Journal of Physics

Low-magnetic field microwave absorption (MA) in superconductors and conducting polymers is analysed in a low-field signal (LFS) version of the MA detecting method. The temperature dependences, hysteretic benavior and other properties of a LFS are compared in superconducting versus non-superonducting systems. Spin selective hopping processes between polarons and bipolarons is proposed to be one of the possible mechanisms of a LFS in non-degenarate conducting polymers.

Efficient Dynamic Unstructured Methods And Applications For Transonic Flows And Hypersonic Stage Separation, Xiaobing Luo

Mechanical & Aerospace Engineering Theses & Dissertations

Relative-moving boundary problems have a wide variety of applications. They appear in staging during a launch process, store separation from a military aircraft, rotor-stator interaction in turbomachinery, and dynamic aeroelasticity.

The dynamic unstructured technology (DUT) is potentially a strong approach to simulate unsteady flows around relative-moving bodies, by solving time-dependent governing equations. The dual-time stepping scheme is implemented to improve its efficiency while not compromising the accuracy of solutions. The validation of the implicit scheme is performed on a pitching NACA0012 airfoil and a rectangular wing with low reduced frequencies in transonic flows. All the matured accelerating techniques, including the …

Apex: Cross-Platform Analysis Program For Exafs, Nicholas Dimakis, Grant Bunker

Physics & Astronomy Faculty Publications

We have developed version 1.0 of a freely available (including source code) suite of basic X-Ray Absorption Fine Structure (XAFS) data analysis programs for data reduction and single scattering analysis. This package is based on the University of Washington (UW/NRL) Fortran 77 programs that are available on the International XAFS Society (IXS) database, complemented by a graphical TCL/TK scripting language based user interface which runs virtually unchanged between platforms, using the native look and feel of the corresponding platform. The package has been tested on MacOS 8.1, Linux, IRIX, Windows95 and NT. Particular emphasis is placed on simplicity, reliability, and …

Rapid Single- And Multiple-Scattering Exafs Debye-Waller Factor Calculations On Active Sites Of Metalloproteins, Nicholas Dimakis, M-Ali Al-Akhras, Grant Bunker

Physics & Astronomy Faculty Publications

This paper describes recent results using our approach to calculating self-consistently single (SS) and multiple-scattering (MS) Debye- Waller factors (DWF) on active sites of metalloproteins. The calculation of MS DWF, together with the Feff7 program allows us to simulate ab-initio EXAFS spectra for a given temperature systems with no adjustable parameters. In our latest report (Dimakis N., and Bunker G., 1998) we calculate, using density functional and semiempirical approaches, the SS and MS DWF for small molecules and compared them to Raman, infrared and EXAFS spectra. In this report calculation of DWFs is done for tetrahedral Zn imidazole, a complex …

Detecting An Association Between Gamma Ray And Gravitational Wave Bursts, Lee Samuel Finn, Soumya Mohanty, Joseph D. Romano

Physics & Astronomy Faculty Publications

If γ-ray bursts (GRBs) are accompanied by gravitational wave bursts (GWBs) the correlated output of two gravitational wave detectors evaluated in the moments just prior to a GRB will differ from that evaluated at other times. We can test for this difference without prior knowledge of either the GWB wave form or the detector noise spectrum. With a model for the GRB source population and GWB spectrum we can put a limit on the in-band rms GWB signal amplitude. Laser-Interferometer Gravitational Wave Observatory I detector observations coincident with 1000 GRB observations could lead us to exclude with 95% confidence associated …

Critical Adsorption Near Edges, Andreas Hanke, M. Krech, F. Schlesener, S. Dietrich

Physics & Astronomy Faculty Publications

Symmetry breaking surface fields give rise to nontrivial and long-ranged order parameter profiles for critical systems such as fluids, alloys, or magnets confined to wedges. We discuss the properties of the corresponding universal scaling functions of the order parameter profile and the two-point correlation function, and determine the critical exponents η∥ and η⊥ for the so-called normal transition.

Measurement Of Inclusive D*± And Associated Dijet Cross Sections In Photoproduction At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

Inclusive photoproduction of D*± mesons has been measured for photon-proton centre-of-mass energies in the range 130 < W < 28OGeV and photon virtuality Q2 < IGeV2. The data sample used corresponds to an integrated luminosity of 37 pb-1. Total and differential cross sections as functions of the D* transverse momentum and pseudorapidity are presented in restricted kinematical regions and the data are compared with next-to-leading order (NLO) perturbative QCD calculations using the "massive charm" and "massless charm" schemes. The measured cross sections are generally above the NLO calculations, in particular in the forward (proton) direction. The large data sample also allows the study of dijet production associated with charm. A significant resolved as well as a direct photon component contribute to the cross section. Leading order QCD Monte Carlo calculations indicate that the resolved contribution arises from a significant charm component in the photon. A massive charm NLO parton level calculation yields lower cross sections compared to the measured results in a kinematic region where the resolved photon contribution is significant.

Measurement Of Jet Shapes In High-Q2 Deep Inelastic Scattering At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

The shapes of jets with transverse energies, EjetT, up to 45 GeV produced in neutral- and charged-current deep inelastic e+p scattering (DIS) at Q2 > 100 GeV2 have been measured with the ZEUS detector at HERA. Jets are identified using a cone algorithm in the η-φ plane with a cone radius of one unit. The jets become narrower as EjetT increases. The jet shapes in neutral- and charged-current DIS are found to be very similar. The jets in neutral-current DIS are narrower than those in resolved processes in photoproduction and closer to those in direct-photon processes for the same ranges in …

Exclusive Electroproduction Of Ρ0 And J/Ψ Mesons At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci

Faculty Publications

Exclusive production of ρ0 and J/ψ mesons in e+p collisions has been studied with the ZEUS detector in the kinematic range 0.25 < Q2 < 50 GeV2, 20 < W < 167 GeV for the ρ0 data and 2 < Q2 < 40 GeV2, 50 < W < 150 GeV for the J/ψ data. Cross sections for exclusive ρ0 and J/ψ production have been measured as a function of Q2, W and t. The spin-density matrix elements r0400, r11-1i and Re r510 have been determined for exclusive ρ0 production as well as r0400 and r041-1 for exclusive J/ψ production. The results are discussed in the context of theoretical models invoking soft and hard phenomena.

Measurement Of The Diffractive Cross Section In Deep Inelastic Scattering Using Zeus 1994 Data, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

The DIS diffractive cross section, dσdiffγ*p→XN/dMx, has been measured in the mass range Mx < 15 GeV for γ*p c.m. energies 60 < W < 200 GeV and photon virtualities Q2 = 7 to 140 GeV2. For fixed Q2 and Mx, the diffractive cross section rises rapidly with W, dσdiffγ*p→X N (Mx, W, Q2)/dMx ∝ Wadiff with adiff = 0.507 ± 0.034 (stat) +0.155-0.046 (syst) corresponding to a t-averaged pomeron trajectory of ̄αℙ = 1.127 ± 0.009 (stat) +0.039-0.012 (syst) which is larger than ̄αℙ observed in hadron-hadron scattering. The W dependence of the diffractive cross section is found to be the same as that of the total cross section for scattering of virtual photons on protons. The data are consistent with the assumption that the diffractive structure function FD(3)2 factorizes according to cursive greek chiℙFD(3)2(cursive greek chiℙ, β, Q2) = (cursive greek chi0//cursive greek chiℙ)nFD(2)2(β, Q2). They are also consistent with QCD based models which incorporate factorization breaking. The rise of cursive greek chiℙFD(3)2 with decreasing cursive greek chiℙ and the weak dependence of FD(2)2 on Q2 suggest a substantial contribution from partonic interactions.

Zeus Results On The Measurement And Phenomenology Of F2 At Low Cursive Greek Chi And Low Q2, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti

Faculty Publications

Measurements of the proton structure function F2 for 0.6 < Q2 < 17 GeV2 and 1.2 × 10-5 < cursive Greek chi < 1.9 × 10 -3 from ZEUS 1995 shifted vertex data are presented. From ZEUS F2 data the slopes dF2/d ln Q2 at fixed cursive Greek chi and din F2/d ln(1/cursive Greek chi) for cursive Greek chi < 0.01 at fixed Q2 are derived. For the latter, E665 data are also used. The transition region in Q2 is explored using the simplest non-perturbative models and NLO QCD. The data at very low Q2 ≤ 0.65 GeV2 are described successfully by a combination of generalised vector meson dominance and Regge theory. From a NLO QCD fit to ZEUS data the gluon density in the proton is extracted in the range 3 × 10-5 < cursive Greek chi < 0.7. Data from NMC and BCDMS constrain the fit at large cursive Greek chi. Assuming the NLO QCD description to be valid down to Q2 ∼ 1 GeV2, it is found that the qq̄ sea distribution is still rising at small cursive Greek chi and the lowest Q2 values whereas the gluon distribution is strongly suppressed.

Measurement Of Multiplicity And Momentum Spectra In The Current And Target Regions Of The Breit Frame In Deep Inelastic Scattering At Hera, J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, J. Repond, R. Stanek, R. Yoshida, Margarita C. K. Mattingly, G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi

Faculty Publications

Charged particle production in neutral current deep inelastic scattering (DIS) has been studied using the ZEUS detector. The evolution of the mean multiplicities, scaled momenta and transverse momenta in Q2 and cursive Greek chi for 10 < Q2 < 5120 GeV2 and cursive Greek chi > 6 × 10-4 has been investigated in the current and target fragmentation regions of the Breit frame. Distributions in the target region, using HERA data for the first time, are compared to distributions in the current region. Predictions based on MLLA and LPHD are inconsistent with the data.

Heavy Metal Pollution In Lake Victoria, J. W. A. Kandoro, M. H. Mikidadi

Tanzania Journal of Science

This work presents the Energy dispersive x-ray flouorences (EDXRF) analysis of water and plant samplesfrom Lake Victoria at Mwanza for heavy metal pollution. Water and plant (Water hyacinth) samples were collected from Lake Victoria around Mwanza municipality from twenty seven locations. There were varying elemental concentrations from different locations reflecting the activities carried out in the vicinity of the lake. Maximum concentration values of up to 1640 mg/L for Pb, 23.3 mg/L for Mn, 42.8 mg/L for Cr, 15.1mg/L for Pb, 23.3mg/L for Cu, and 742.5 mg/L for Zn, were observed. Possible sources of the elements are discussed, from which …

A Person Computer Programme For Fitting Of Moessbauer Spectra, J. W. A. Kandoro

Tanzania Journal of Science

A Computer code for fitting spectra obtained in Moessbauer spectroscopy on a personal computer is described. The code is designed around a least-squares routine which fits the characteristics peaks in a Moessbauer spectrum with Lorentzian shaped peaks and the background of a spectrum with a polynomial function. The least squares routing is based on the Newton-Raphson algorithm. The method is implemented in a computer program written in quick basic for which prove that the program in quick basic for IBM compatible personal computer. Tests are described which prove that the program is able to provide reliable values for the parameters.

Search For Higgs Bosons Produced In Association With A Vector Boson In Pp̅ Collisions At √S = 1.8 Tev, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We search for Higgs bosons produced in association with a massive vector boson in 91 ± 7 pb^-1 of pp̅ collisions at √s =1.8 TeV recorded by the Collider Detector at Fermilab. We assume the Higgs scalar H⁰ decays to a bb̅ pair with branching ratio β, and we consider the hadronic decays of the vector boson V (W or Z). Observations are consistent with background expectations. We place 95% confidence level upper limits on σ (pp̅→H⁰V) β as a function of the scalar mass (MH⁰) …