Other Physics Commons^™

Developing A B-Jet Tagging Algorithm For Alice: Lessons From Cdf, Paul Chester-John Carlson

Physics

This paper compares the detectors and algorithms developed and used at both A Large Ion Collider Experiment (ALICE) and the Collider Detector at Fermilab (CDF). We found that the detectors share many similarities in data collection and analysis methods and that by adapting algorithms that have been tested and used at CDF, ALICE could augment its existing algorithms. The algorithms formed from this adaptation will help ALICE isolate b-jets quickly and explore the quark-gluon plasma, ultimately expanding our understanding of the strong nuclear force and its role in the evolution of our universe.

High Resolution Solar Observations From First Principles To Applications, Angelo P. Verdoni

Dissertations

The expression "high-resolution observations" in Solar Physics refers to the spatial, temporal and spectral domains in their entirety. High-resolution observations of solar fine structure are a necessity to answer many of the intriguing questions related to solar activity. However, a researcher building instruments for high-resolution observations has to cope with the fact that these three domains often have diametrically opposed boundary conditions. Many factors have to be considered in the design of a successful instrument. Modern post-focus instruments are more closely linked with the solar telescopes that they serve than in past. In principle, the quest for high-resolution observations already …

Carbon Nanotube Electronic Structures As Anti-Corrosion Coatings, Sreeya Sreevatsa

Dissertations

A new concept of corrosion prevention is considered in this study. Diode-like and transistor-like structures have been fabricated and analyzed in the study of ionic flow through the resulting potential barriers. The structures were made of functionalized carbon nanotubes. Carbon nanotubes are known for many remarkable properties among which is being chemically inert. Taking advantage of this property, a study of corrosion of steel was undertaken.

In the first case study, successive layers of functionalized carbon nanotubes were deposited to form p-n junctions on steel substrates. It was demonstrated that the corrosion was indeed impeded by the potential barrier formed …

Probing The Complex Magnetic, Electronic And Structural Properties In Correlated Manganese Oxides, Peng Gao

Dissertations

Rare-earth Manganese Oxides (RMnO₃) exhibit two distinct structural phases: the orthorhombic structure and the hexagonal structure. The doped orthorhombic phase exhibits a metal to insulator transition, charge ordering and a strong response of electron transport properties to magnetic fields (colossal magneto-resistance). At low temperatures, this system may also exhibit a finite polarization which couples to external magnetic fields. The hexagonal phase is known to have a large spontaneous polarization at high temperatures which couples to the low temperature magnetic order. These materials are important from the basic point of view of understanding strong electronic correlations and …

Scene-Based Nonuniformity Correction With Reduced Ghosting Using A Gated Lms Algorithm, Russell C. Hardie, Frank Orion Baxley, Brandon J. Brys, Patrick C. Hytla

Electrical and Computer Engineering Faculty Publications

In this paper, we present a scene-based nouniformity correction (NUC) method using a modified adaptive least mean square (LMS) algorithm with a novel gating operation on the updates. The gating is designed to significantly reduce ghosting artifacts produced by many scene-based NUC algorithms by halting updates when temporal variation is lacking. We define the algorithm and present a number of experimental results to demonstrate the efficacy of the proposed method in comparison to several previously published methods including other LMS and constant statistics based methods. The experimental results include simulated imagery and a real infrared image sequence. We show that …

African-American College Student Attitudes Toward Physics And Their Effect On Achievement, Carl Timothy Drake

Dissertations

The purpose of this study was to investigate factors affecting the attitudes that African-American college students have towards introductory college physics. The population targeted for this study consisted of African-American males and females enrolled in introductory college physics classes at an urban public historical black college or university (HBCU) located in the southeastern United States. Nine of the Fennema- Sherman Mathematics Attitude Scales, modified for physics, were used to analyze the attitudes of the 135 participants enrolled in an introductory college physics class. The nine scales used to measure the students' attitudes were Attitude Toward Success in Physics Scale (AS), …

Intermodulation And Parametric Amplification In A Superconducting Stripline Resonator Integrated With A Dc-Squid, B. Abdo, O. Suchoi, E. Segev, O. Shtempluck, M. Blencowe, E. Buks

Dartmouth Scholarship

We utilize a superconducting stripline resonator containing a dc-SQUID as a strong intermodulation amplifier exhibiting a signal gain of 24dB and a phase modulation of 30dB. Studying the system response in the time domain near the intermodulation amplification threshold reveals a unique noise-induced spikes behavior. We account for this response qualitatively via solving numerically the equations of motion for the integrated system. Furthermore, employing this device as a parametric amplifier yields an abrupt rise of 38dB in the generated side-band signal.

Hyperspectral Imaging Of A Turbine Engine Exhaust Plume To Determine Radiance, Temperature, And Concentration Spatial Distributions, Spencer J. Bowen

Theses and Dissertations

The usefulness of imaging Fourier transform spectroscopy (IFTS) when looking at a rapidly varying turbine engine exhaust scene was explored by characterizing the scene change artifacts (SCAs) present in the plume and the effect they have on the calibrated spectra using the Telops, Inc.-manufactured Field-portable Imaging Radiometric Spectrometer Technology, Midwave Extended (FIRST-MWE). It was determined that IFTS technology can be applied to the problem of a rapidly varying turbine engine exhaust plume due to the zero mean, stochastic nature of the SCAs, through the use of temporal averaging. The FIRST-MWE produced radiometrically calibrated hyperspectral datacubes, with calibration uncertainty of 35% …

True-Time Delay Steering Of Phased Array Radars Using Slow Light, Mark Bashkansky, Zachary Dutton, Armen Gulian, David Walker, Fredrik Fatemi, Michael Steiner

Mathematics, Physics, and Computer Science Faculty Articles and Research

Application of slow light linear delay to squint-free (true-time delay) steering of phased array radar antennae is discussed. Theoretical analysis is provided on true-time delay radar requirements, including delay precision, amplitude precision, and bandwidth. We also discuss an improvement to the slow light technique based on stimulated Brillouin scattering by using a Faraday rotator mirror that provides temporally stable, linear (with pump power) delay, applicable to practical implementations. Future directions are considered.

Modeling The Magnetic Pickup Of An Electric Guitar, Nicholas G. Horton, Thomas R. Moore

Student-Faculty Collaborative Research Publications

The magnetic pickup of an electric guitar uses electromagnetic induction to convert the motion of a ferromagnetic guitar string into an electrical signal. Although the magnetic pickup is often cited as an everyday application of Faraday's law, few sources mention the distortion that the pickup generates when converting string motion into an electric signal, and even fewer attempt to analyze and explain this distortion. By modeling the magnet and ferromagnetic wire as surfaces with magnetic charge, an intuitive model that accurately predicts the output of a magnetic guitar pickup can be constructed. More
importantly, this model can be understood and …

Terahertz Response Of Microfluidic-Jetted Fabricated 3d Flexible Metamaterials, Yew Li Hor

Dissertations

Conventional materials exhibit some restrictions on their electromagnetic properties. Especially in terahertz region, for example, materials that exhibit magnetic response are far less common in nature than materials that exhibit electric response. However, materials can be designed, namely artificial man-made metamaterials that exhibit electromagnetic properties that are not found in natural materials by adjusting, for example, the dielectric, magnetic or structural parameters of the constituent elements.

This dissertation demonstrates the use of new fabrication techniques to construct metamaterials in THz range via a material deposition system. The metamaterials are fabricated by stacking alternative layers with conventional designs such as single …

Synchrotron Radiation-Based Characterization Of Gan- Based Mqw Structures And Strongly Correlated Materials, Sean M. O'Malley

Dissertations

The following dissertation applies synchrotron radiation-based characterization techniques to the fields of gallium nitrides, multiferroic manganites, and self-assembled nano-domain oxide films. These material systems were chosen due to their unusual properties and potential device applications, which have made them very attractive to the scientific community.

Synchrotron-based High Resolution X-ray Diffraction (HRXRD) was used to characterize the structural properties of GaN-based multiple quantum well (MQW) structures grown on trapezoidal shaped GaN ridges. Results where interpreted within the framework of vapor-phase diffusion and surface-migration effects during the metalorganic vapor phase epitaxial growth. The relatively short diffusion length of group- III precursors and …

Modeling Weak Gravitational Lensing Through C++, Christopher Cepero

Undergraduate Review

Gravitational Lensing has become an integral part of astrophysics and the study of matter in the universe. In weak gravitational lensing, an object appears distorted when viewed from the observer’s perspective. This is caused by the bundle of light being distorted by an object of considerable mass. Because the distance to each part of this bundle is not the same, the rays of light are affected differently causing a shearing and magnification of the image. This alteration in the image we see can be modeled using the thin lens approximation. By integrating the equations for light travel based on general …

An Optical Scalar Approach To Weak Gravitation Lensing, Louis Bianchini

Undergraduate Review

We assume a thick gravitational lens governed by a Baltz n=1 matter density model. From the gravitational potential we then derive expressions for a Weyl tensor component and Ricci tensor component. A perturbative approach is taken to solve for the convergence and shear as given by Sach’s equation. By applying the geodesic deviation equation to a bundle of light rays with our expressions for the optical scalars we are able to derive expressions for the image shape and size at any point along the path from source to observer, in the case of an axially symmetric lens and source.