Physics Commons^™

Simultaneous Radar And Video Meteors, Robert J. Weryk

Electronic Thesis and Dissertation Repository

The goal of this thesis is to better understand the physical and chemical properties of meteoroids by using simultaneous radar and video observations of meteors. The Canadian Meteor Orbit Radar (CMOR) and several Gen-III image-intensified CCD cameras were used to measure common meteors and validate metric errors determined through Monte Carlo modelling and to relate radar electron line density (q) to video photon radiant power (I). By adopting an ionisation coefficient from Jones (1997) and using recorded measurements of q/I, a corresponding estimate of the fraction of meteoroid kinetic energy loss converted into light (luminous efficiency) was found.

It was …

Aspects Of General Relativity In 1+1 Dimensions, Richard D. Mellinger Jr

Physics

What would be the properties of a universe with only one spatial dimension and one time dimension? General relativity in 1+1 dimensions is unique since the two curvature terms in the Einstein field equations cancel. This makes the Einstein field equations algebraic rather than differential equations. This special feature can make 1+1 dimensionality attractive as an instructional tool to simplify the mathematics that many beginners find opaque. We explore the implications and features of the Einstein field equations in 1+1 dimensions and find they provide a surprisingly rich and interesting model. We then study an alternate theory and its implications …

Development Of A Novel Technique For Predicting Tumor Response In Adaptive Radiation Therapy, Rebecca Marie Seibert

Doctoral Dissertations

This dissertation concentrates on the introduction of Predictive Adaptive Radiation Therapy (PART) as a potential method to improve cancer treatment. PART is a novel technique that utilizes volumetric image-guided radiation therapy treatment (IGRT) data to actively predict the tumor response to therapy and estimate clinical outcomes during the course of treatment. To implement PART, a patient database containing IGRT image data for 40 lesions obtained from patients who were imaged and treated with helical tomotherapy was constructed. The data was then modeled using locally weighted regression. This model predicts future tumor volumes and masses and the associated confidence intervals based …

Evaluation Of Polymer Gel Dosimeters For Measurements Of Dose And Let In Proton Beams, Kevin M. Vredevoogd

Dissertations & Theses (Open Access)

This project assessed the effectiveness of polymer gel dosimeters as tools for measuring the dose deposited by and LET of a proton beam. A total of three BANG® dosimeter formulations were evaluated: BANG®-3-Pro-2 BANGkits™ for dose measurement and two BANG®-3 variants, the LET-Baseline and LET-Meter dosimeters, for LET measurement. All dosimeters were read out using an OCT scanner. The basic characteristics of the BANGkits™ were assessed in a series of photon and electron irradiations. The dose-response relationship was found to be sigmoidal with a threshold for response of approximately 15 cGy. The active region of the dosimeter, the volume in …

Utilization Of A Tropospheric-Stratospheric Lidar System To Study Mountain Induced Gravity Waves Over Jenny Jump State Forest, Anthony Teti

Theses

Gravity waves are a dominant driver of the middle and lower atmospheric circulation. Yet such waves have been difficult to study due to their inherent small spatial and temporal scales and synoptic occurrence, and thus require advanced experimental systems. In this thesis first results are presented from a newly constructed tropospheric-stratospheric lidar operating at the New Jersey Institute of Technology-United Astronomy Clubs of New Jersey site in Jenny Jump State Forest in northwest New Jersey. The system utilizes a 4-W 532-nm Nd:YAG laser transmitter and a 4-inch telescope receiver to collect backscattered photons from the lower atmosphere in order to …

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

Dissertations & 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, …

Development And Implementation Of The Use Of Optically Stimulated Luminescent Detectors In The Radiological Physics Center Anthropomorphic Quality Assurance Phantoms, Jennelle Bergene

Dissertations & Theses (Open Access)

The Radiological Physics Center (RPC) uses both on-site and remote reviews to credential institutions for participation in clinical trials. Anthropomorphic quality assurance (QA) phantoms are one tool the RPC uses to remotely audit institutions, which include thermoluminescent dosimeters (TLDs) and radiochromic film. The RPC desires to switch from TLD as the absolute dosimeter in the phantoms, to optically stimulated luminescent dosimeters (OSLDs), but a problem lies in the angular dependence exhibited by the OSLD. The purpose of this study was to characterize the angular dependence of OSLD and establish a correction factor if necessary, to provide accurate dosimetric measurements as …

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 …

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 …

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

Physics

No abstract provided.

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 …

Atomistic Simulations Of The Fusion-Plasma Material Interface, Mostafa Jon Dadras

Doctoral Dissertations

A key issue for the successful performance of current and future fusion reactors is understanding chemical and physical processes at the Plasma Material Interface (PMI). The material surfaces may be bombarded by plasma particles in a range of impact energies (1 eV - a few keV) and kept at a range of temperatures (300 - 1000 K). The dominant processes at the PMI are reflection and retention of impacting particles and sputtering (chemical and physical). Sputtering leads to surface erosion and pollution of the plasma, both of which degrade reactor performance. Retention influences the recycling of the plasma, and in …

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 & 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 …

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.

Hyperpolarized Noble Gas Magnetic Resonance Imaging And Dynamic Spectroscopy For Investigation Of Rat Models Of Lung Inflammation, Matthew S. Fox

Electronic Thesis and Dissertation Repository

Imaging of the lungs using non-ionizing approaches such as hyperpolarized ³He and ¹²⁹Xe magnetic resonance imaging (MRI) is a useful tool both for research and clinical applications. This work focused on development of ¹²⁹Xe MRI techniques to investigate inflammation in rat lungs. A rodent model of inflammation, specifically radiation-induced lung injury (RILI) was developed using a collimated ⁶⁰Co source. A quantitative MRI technique measuring absolute ventilated lung volume (|VLV|) was performed using ¹²⁹Xe and ³He. Following a comparison between |VLV| values obtained from rats using the previously established ³He method and those obtained …

Terahertz Wireless Communication, Ke Su

Dissertations

The goal of this thesis is to explore Terahertz (THz) wireless communication technology. More specifically the objective is to develop and characterize several THz communication systems and study the effect of atmosphere propagation through fog droplets and dust particles on THz communications.

For demonstration, a THz continuous wave (CW) photomixing system is designed. Terahertz signals are phase encoded with both analog ramp signals and pseudorandom binary data, transmitted over a short distance, and detected. The limitation of transmission bandwidth, low single to noise ratio, vibration effects are also analyzed. In order to study and compare propagation features of THz links …

Non-Destructive Evaluation Of Agglomerated Cork Products Using Thz Spectroscopy And Imaging, Han Zhang

Theses

Terahertz spectroscopy from 0.15 to 0.3 THz is used to classify agglomerated cork products. Position dependent scattering of radiation allows one to image the internal structure of cork products. Previous studies have focused on natural (solid) cork stoppers. In this study, the feasibility of classifying agglomerated cork structures using THz imaging and spectroscopy is investigated. Both THz images and spectra are used to classify the agglomerated cork samples. Classification of the samples used three methods: visible examination of the THz images, statistical analysis of the pixel intensities, and a polynomial regression of the THz spectral data averaged over all pixels. …