Other Physics Commons^™

Development And Implementation Of A Remote Audit To Ol For High Dose Rate (Hdr) 192ir Brachytherapy Using Optically Stimulated Luminescence Dosimetry, Kevin Casey

Dissertations and Theses (Open Access)

This work aimed to create a mailable and OSLD-based phantom with accuracy suitable for RPC audits of HDR brachytherapy sources at institutions participating in NCI-funded cooperative clinical trials. An 8 × 8 × 10 cm³ prototype with two slots capable of holding nanoDot Al₂O₃:C OSL dosimeters (Landauer, Glenwood, IL) was designed and built. The phantom has a single channel capable of accepting all ¹⁹²Ir HDR brachytherapy sources in current clinical use in the United States. Irradiations were performed with an ¹⁹²Ir HDR source to determine correction factors for linearity with dose, dose rate, …

The Double Pendulum: Construction And Exploration, Benjamin J. Knudson

Physics

The exploration of a nonlinear mechanical system, the Double Pendulum, a physical pendulum on the end of a physical pendulum, using analytic and experimental approaches. Also included discussion of the design and construction of the Double Pendulum apparatus to work with Vernier LabPro and LoggerPro. The apparatus outputs live data of the angles to a LoggerPro which collects and produces time evolution graphs as well as a corresponding animation lending itself to comparison with theoretical models. Normal mode frequencies are found both analytically and experimentally for the the general (real) double pendulum. Examples of both simple (periodic) and complex (chaotic) …

Development Of A Pyrotechnic Shock Simulation Apparatus For Spacecraft Applications, Joseph Binder, Matthew Mccarty, Chris Rasmussen

Aerospace Engineering

This report details the research, design, construction, and testing of a pyrotechnic shock simulation apparatus for spacecraft applications. The apparatus was developed to be used in the Space Environments Lab at California Polytechnic State University. It will be used for testing spacecraft components with dimensions up to 24”x12”x12” as well as CubeSats. Additionally, it may be used as an instructional or demonstrational tool in the Aerospace Department’s space environments course. The apparatus functions by way of mechanical impact of an approximately 20 lb stainless steel swinging hammer. Tests were performed to verify the simulator’s functionality. Suggestions for improvement and further …

Boundary Stabilization Of Torsional Vibrations Of A Solar Panel, Prasanta K. Nandi, Ganesh C. Gorain, Samarjit Kar

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we study a boundary stabilization of the torsional vibrations of a solar panel. The panel is held by a rigid hub at one end and is totally free at the other. The dynamics of the overall system leads to hybrid system of equations. It is set to a certain initial vibrations with a control torque as a stabilizer at the hub end only. Taking a non-linear damping as boundary stabilizer, a uniform exponential energy decay rate is obtained directly. Thus an explicit form of uniform stabilization of the system is achieved by means of the exponential energy …

Two Numerical Algorithms For Solving A Partial Integro-Differential Equation With A Weakly Singular Kernel, Jeong-Mi Yoon, Shishen Xie, Volodymyr Hrynkiv

Applications and Applied Mathematics: An International Journal (AAM)

Two numerical algorithms based on variational iteration and decomposition methods are developed to solve a linear partial integro-differential equation with a weakly singular kernel arising from viscoelasticity. In addition, analytic solution is re-derived by using the variational iteration method and decomposition method.

New Explicit Solutions For Homogeneous Kdv Equations Of Third Order By Trigonometric And Hyperbolic Function Methods, Marwan Alquran, Roba Al-Omary, Qutaibeh Katatbeh

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we study two-component evolutionary systems of the homogeneous KdV equation of the third order types (I) and (II). Trigonometric and hyperbolic function methods such as the sine-cosine method, the rational sine-cosine method, the rational sinh-cosh method, sech-csch method and rational tanh-coth method are used for analytical treatment of these systems. These methods, have the advantage of reducing the nonlinear problem to a system of algebraic equations that can be solved by computerized packages.

Gaussian Beam Steering On A Target Plane Via High Speed Orthogonal Mirror-Mounted Galvanometers, Keith Gresiak

Physics

No abstract provided.

Mhd Mixed Convective Flow Of Viscoelastic And Viscous Fluids In A Vertical Porous Channel, R. Sivaraj, B. R. Kumar, J. Prakash

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we analyze the problem of steady, mixed convective, laminar flow of two incompressible, electrically conducting and heat absorbing immiscible fluids in a vertical porous channel filled with viscoelastic fluid in one region and viscous fluid in the other region. A uniform magnetic field is applied in the transverse direction, the fluids rise in the channel driven by thermal buoyancy forces associated with thermal radiation. The equations are modeled using the fully developed flow conditions. An exact solution is obtained for the velocity, temperature, skin friction and Nusselt number distributions. The physical interpretation to these expressions is examined …

Studying Beam Dynamics At Cesrta, Matthew (Matt) Randazzo

Physics

The Cornell Electron Storage Ring Test Accelerator (CesrTA) is a particle accelerator acting primarily as a laboratory for studying accelerator physics under a variety of conditions. Here, the experimental program on electron cloud effects is one of the highest-priority research and development projects during the International Linear Collider (ILC) Technical Design Phase 1. These electron clouds are of particular concern for the design of future low emittance rings like those in the ILC because of how they can adversely affect the performance of accelerators. The impact of electron clouds on the dynamics of individual bunches along a train known as …

Evolution Of 3-D Magnetic Topology In Flare-Productive Active Regions, Yixuan Li

Dissertations

Solar eruptive phenomena, such as flares and coronal mass ejections (CMEs), derive their energy from complex magnetic fields and are the principal source of disturbances that affect space weather. Although physical mechanism and dynamic morphology of flares have been a subject of intense research, many aspects of the flaring process still remain unclear. The objective of this dissertation is to advance the understanding of the physics behind solar flares based on observations, simulations and nonlinear force-free (NLFF) field modeling of magnetic fields.

The data used in this study are obtained from several ground-based or space-borne instruments, including BBSO/DVMG, Hinode/SOT/SP, SDO/HMI …

Magnetic Vortices On Closely Packed Spherically Curved Surfaces, Robert Streubel, Denys Makarov, Florian Kronast, Volodymyr Kravchuk, Manfred Albrecht, Oliver G. Schmidt

Robert Streubel Papers

We investigate the change of magnetic vortex states driven by curvature. The equilibrium state and magnetization reversal of soft magnetic permalloy (Py, Ni ₈₀Fe ₂₀) caps on self-assembled spherical particles with diameters of 100, 330, and 800 nm are investigated, revealing the vortex ground state for individual caps and closely packed cap arrays. The magnetic coupling between vortices is substantially reduced due to the shape of the cap as apparent in a much weaker dependence of the magnetization reversal process on the separation distance. Interestingly, the remaining coupling is still sufficiently large to introduce chirality frustrated vortex states …

Magnetic Ordering And Structural Phase Transition In Strained Ultrathin Srruo3/Srtio3 Superlattice, Mingquiang Gu, Xiaoshan Wu, Guoping Zhang

Symposium 2012

No abstract provided.

Characterization Of A Thermal Reservoir For Consistent And Accurate Annealing Of High Sensitivity Thermoluminescence Dosimeters In Brachytherapy Dosimetry, William Patrick Donahue

Honors Scholar Theses

Unlike regular TLD, an accurate and consistent annealing of the high-sensitivity TLD at 240 ˚C for 15 minutes is challenging using conventional annealing ovens because the temperature in the oven chamber varies drastically over the 15-minute period after the opening (to put the TLD tray in) and closing of oven door. The temperature in the oven drops dramatically after the door is opened and ramps up gradually after the door is closed, often accompanied with significant temperature overshoot. Because an overshoot by more than 5 ˚C can significantly reduce the sensitivity of the TLD and the ramp-up profile varies with …

Investigation Of Negative Differential Resistance Phenomena In Quantum Well Heterostructures, Nazariy Andrushchak

Graduate Theses and Dissertations

Increasing interest in entirely new possibilities for quantum mechanical description of carriers transport is becoming more evident with the developing advancements in epitaxial growth technique. Consequently, molecular beam epitaxy (MBE) technique is considered to be the most precise technique that allows the growth of ultra-thin layers of different compositions.

Those structures can be designed to investigate the wave-nature of carriers, which broadens the possibilities in device design and fabrication for a specific area. In this thesis the fundamental study of the real space charge transfer (RST) mechanism that took place in quantum well heterostructures and led to the negative differential …

Verification Of The Clinical Implementation Of The Respiratory Gated Beam Delivery Technique With Synchrotron-Based Proton Irradiation, Yoshikazu Tsunashima

Dissertations and Theses (Open Access)

The clinical advantage for protons over conventional high-energy x-rays stems from their unique depth-dose distribution, which delivers essentially no dose beyond the end of range. In order to achieve it, accurate localization of the tumor volume relative to the proton beam is necessary. For cases where the tumor moves with respiration, the resultant dose distribution is sensitive to such motion. One way to reduce uncertainty caused by respiratory motion is to use gated beam delivery. The main goal of this dissertation is to evaluate the respiratory gating technique in both passive scattering and scanning delivery mode. Our hypothesis for the …

Out-Of-Surface Vortices In Spherical Shells, Volodymyr P. Kravchuk, Denis D. Sheka, Robert Streubel, Denys Makarov, Oliver G. Schmidt, Yuri Gaididei

Robert Streubel Papers

The interplay of topological defects with curvature is studied for out-of-surface magnetic vortices in thin spherical nanoshells. In the case of an easy-surface Heisenberg magnet it is shown that the curvature of the underlying surface leads to a coupling between the localized out-of-surface component of the vortex with its delocalized in-surface structure, i.e., polarity-chirality coupling. © 2012 American Physical Society.

Breaking Glass: Exploring The Relationship Between Kinetic Energy And Radial Fracturing In Plate Glass, Andrea Hulman

Scripps Senior Theses

When glass breaks from the impact of an object, it exhibits a distinctive shattering pattern comprised of two different regions. This pattern was investigated using experimental impacts and predicted using Young’s Modulus. Results were not as expected, and it is likely that there exists error in some measurements. Further investigation of this topic is recommended.

Electric Susceptibility For Strongly Magnetized Electron-Positron Plasma At Finite Temperature And Density, Paul L. Springsteen ^, Efrain J. Ferrer *, Angel Sanchez

COURI Symposium Abstracts, Spring 2012

We study the electric response of a relativistic electron-positron plasma at finite density and temperature in the presence of a strong magnetic field. The results are found by calculating the polarization tensor of such a system in the one-loop approximation. It was determined that a photon traveling through this medium acquires a Debye mass that depends on the magnitude of the magnetic field, temperature and chemical potential. We also found that the system electric susceptibility is anisotropic, with a component transverse to the magnetic field, which is that of vacuum, and a longitudinal component, which decreases with the temperature and …

Using Radial Basis Functions To Interpolate Along Single-Null Characteristics, Maria Babiuc-Hamilton, Clyde E. Meador

Physics Faculty Research

The Cauchy-Characteristic Extraction (CCE) technique is the most precise method available for the computation of the gravitational waves obtained from numerical simulations of binary black hole mergers. This technique utilizes the characteristic evolution to extend the simulation to null infinity, where the waveform is computed in inertial coordinates. Although we recently made CCE publicly available to the numerical relativity community, there is still room for improvement, and the most important is enhancing the overall accuracy of the code, by upgrading the numerical methods used for interpolation and differentiation. One of the most promising ways is to use the Radial Basis …

Parameterized Special Theory Of Relativity (Pstr), Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

We have parameterized Einstein’s thought experiment with atomic clocks, supposing that we knew neither if the space and time are relative or absolute, nor if the speed of light was ultimate speed or not. We have obtained a Parameterized Special Theory of Relativity (PSTR), first introduced in 1982. Our PSTR generalized not only Einstein’s Special Theory of Relativity, but also our Absolute Theory of Relativity, and introduced three more possible Relativities to be studied in the future. After the 2011 CERN’s superluminal neutrino experiments, we recall our ideas and invite researchers to deepen the study of PSTR, ATR, and check …